High Energy Physics - Phenomenology
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Showing new listings for Friday, 22 November 2024
- [1] arXiv:2411.13634 [pdf, html, other]
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Title: Individual Neutrino Masses From a SupernovaComments: 18 pages, 13 figures, 2 tables. Comments welcome!Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
A nearby supernova will carry an unprecedented wealth of information about astrophysics, nuclear physics, and particle physics. Because supernova are fundamentally neutrino driven phenomenon, our knowledge about neutrinos -- particles that remain quite elusive -- will increase dramatically with such a detection. One of the biggest open questions in particle physics is related to the masses of neutrinos. Here we show how a galactic supernova provides information about the masses of each of the three mass eigenstates \emph{individually}, at some precision, and is well probed at JUNO. This information comes from several effects including time delay and the physics within the supernova. The time delay feature is strongest during a sharp change in the flux such as the neutronization burst; additional information may also come from a QCD phase transition in the supernova or if the supernova forms a black hole. We consider both standard cases as dictated by local oscillation experiments as well as new physics motivated scenarios where neutrino masses may differ across the galaxy.
- [2] arXiv:2411.13641 [pdf, html, other]
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Title: Bounds on the bubble wall velocityComments: 47 pages, 8 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Determining the bubble wall velocity in first-order phase transitions is a challenging task, requiring the solution of (coupled) equations of motion for the scalar field and Boltzmann equations for the particles in the plasma. The collision terms appearing in the Boltzmann equation present a prominent source of uncertainty as they are often known only at leading log accuracy. In this paper, we derive upper and lower bounds on the wall velocity, corresponding to the local thermal equilibrium and ballistic limits. These bounds are completely independent of the collision terms.
For the ballistic approximation, we argue that the inhomogeneous plasma temperature and velocity distributions across the bubble wall should be taken into account. This way, the hydrodynamic obstruction previously observed in local thermal equilibrium is also present for the ballistic approximation. This is essential for the ballistic approximation to provide a lower bound on the wall velocity. We use a model-independent approach to study the behaviour of the limiting wall velocities as a function of a few generic parameters, and we test our developments in the singlet extended Standard Model. - [3] arXiv:2411.13664 [pdf, html, other]
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Title: Optimal Sensitivity of Anomalous Charged Triple Gauge Couplings through $W$ boson helicity at the $e^+e^-$ collidersComments: 18 pages, 8 figures, 3 tablesSubjects: High Energy Physics - Phenomenology (hep-ph)
We study the estimation of anomalous charged triple gauge couplings (cTGCs) parameterized in a model-independent Standard Model effective field theory (SMEFT) framework via $WW$ production followed by semi-leptonic decay at the $e^+e^-$ colliders. The anomalous $(WWV~(V=\gamma,Z))$ couplings are given in terms of Wilson coefficients of three CP-conserving and two CP-violating dimension-6 operators in the HISZ basis. We adopt the optimal observable technique (OOT) to extract the sensitivity of these anomalous couplings and compare it with the latest experimental limits on anomalous couplings studied at the LHC. The limits on the anomalous couplings obtained via OOT are significantly tighter than the ones obtained using standard $\chi^2$ analysis. The impact of different helicity combinations of the $W$ boson pair in determining optimal sensitivity is analyzed. The constraints on CP-violating operators from the electron electric dipole moment (EDM) are also discussed.
- [4] arXiv:2411.13729 [pdf, html, other]
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Title: Probing the Inert Doublet Model via Vector-Boson Fusion at a Muon ColliderComments: 41 pages, 14 figures, 6 tablesSubjects: High Energy Physics - Phenomenology (hep-ph)
In this work, we explore the discovery potential of the Inert Doublet Model (IDM) via the vector boson fusion (VBF) channel at a muon collider with centre-of-mass energy of 10 TeV. The Inert Doublet Model is a two-Higgs-doublet model variant with an unbroken discrete $\mathbb{Z}_2$ symmetry, featuring new stable scalar particles that can serve as dark matter candidates. Current dark matter data constrain the phenomenologically viable parameter space of the IDM and render certain collider signatures elusive due to tiny couplings. However, VBF-type processes can still exhibit significant enhancements compared to the Standard Model, presenting a promising avenue to probe the IDM at a high-energy muon collider. We consider as our specific target process $\mu^+\mu^-\to \nu_\mu\bar{\nu}_\mu AA\to \nu_\mu\bar{\nu}_\mu jj \ell\ell HH$, where $H$ and $A$ are the lightest and second-lightest new scalars and $\ell$ can be electrons or muons. We perform both cut-based and machine-learning improved sensitivity analyses for such a signal, finding a population of promising benchmark scenarios. We additionally investigate the impact of the collider energy by comparing sensitivities to the target process at 3 TeV and 10 TeV. Our results provide a clear motivation for a muon collider design capable of reaching a 10 TeV centre-of-mass energy. We furthermore discuss constraints stemming from new-physics corrections to the Higgs to di-photon decay rate as well as the trilinear Higgs coupling in detail, using state-of-the-art higher-order calculations.
- [5] arXiv:2411.13756 [pdf, html, other]
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Title: Scotogenic dark matter from gauged $B-L$Subjects: High Energy Physics - Phenomenology (hep-ph)
We propose a $U(1)_{B-L}$ gauge extension to the SM, in which the dark sector is stabilized through a matter parity symmetry preserved after spontaneous symmetry breaking. The fermion spectrum includes three neutral right-handed fields with $B-L$ charges $(-4,-4, 5)$, that make the model free of gauge anomalies. Two of these neutral fermion fields serve as mediators in a scotogenic mechanism for light-active Majorana neutrino masses. The corresponding neutrino mass matrix has rank 2, predicting a massless state and a lower bound for neutrinoless double beta decay. Regions in the parameter space consistent with dark matter relic abundance are accomplished by the lightest neutral mediator.
- [6] arXiv:2411.13837 [pdf, html, other]
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Title: Probing Compressed Mass Spectrum Supersymmetry at the LHC with the Vector Boson Fusion TopologySubjects: High Energy Physics - Phenomenology (hep-ph)
We present a phenomenology study probing pair production of supersymmetric charginos and neutralinos ("electroweakinos") with the vector boson fusion (VBF) topology in proton-proton collisions at CERN's Large Hadron Collider (LHC). In particular, we examine the compressed-mass spectrum phase space that has been traditionally challenging due to experimental constraints. The final states considered have two jets, large missing transverse momentum, and one, two, or three light leptons. Different model scenarios are considered for the production and decays of the electroweakinos. A novel high-performance and interpretable sequential attention-based machine learning algorithm is employed for signal-background discrimination and is observed to significantly improve signal sensitivity over traditional methods. We report expected signal significances for integrated luminosities of $137$, $300$, and $3000$ $\textrm{fb}^{-1}$ corresponding to the current data acquired at the LHC, expectation for the end of Run 3, and the expectation for the high-luminosity LHC. Our methodology results in projected 95\% confidence level bounds that cover chargino masses up to 1.1 TeV in compressed-mass spectrum scenarios within the R-parity conserving minimal supersymmetric standard model. This parameter space, currently beyond the reach of ATLAS and CMS searches at the LHC, is traditionally challenging to explore due to significant Standard Model backgrounds and low signal cross-sections.
- [7] arXiv:2411.13845 [pdf, html, other]
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Title: Transverse spin effects and light-quark dipole moments at lepton collidersComments: 6 pages, 3 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
We propose to probe light-quark dipole interactions at lepton colliders using the azimuthal asymmetry of a collinear dihadron pair $(h_1h_2)$ produced in association with another hadron $h'$. This asymmetry, arising from quantum interference in the quark spin space, is exclusively sensitive to dipole interactions at the leading power of the new physics scale and simultaneously probes both the real and imaginary components of the dipole couplings. By combining all possible channels of $h'$, this method allows for disentangling the up and down quark dipole moments and has the potential to significantly strengthen current constraints by one to two orders of magnitude.
- [8] arXiv:2411.13895 [pdf, html, other]
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Title: Neutrino mass genesis in Scoto-Inverse Seesaw with Modular $A_4$Comments: 28 Pages, 11 Figures and 02 tablesSubjects: High Energy Physics - Phenomenology (hep-ph)
We propose a hybrid scotogenic inverse seesaw framework in which the Majorana mass term is generated at the one-loop level through the inclusion of a singlet fermion. This singlet Majorana fermion also serves as a viable thermal relic dark matter candidate due to its limited interactions with other fields. To construct the model, we adopt an $A_4$ flavour symmetry in a modular framework, where the odd modular weight of the fields ensures their stability, and the specific modular weights of the couplings yield distinctive modular forms, leading to various phenomenological consequences. The explicit flavour structure of the mass matrices produces characteristic correlation patterns among the parameters. Furthermore, we examine several testable implications of the model, including neutrinoless double beta decay ($0\nu\beta\beta$), charged lepton flavour violation (cLFV), and direct detection prospects for the dark matter candidate. These features make our model highly testable in upcoming experiments.
- [9] arXiv:2411.13910 [pdf, html, other]
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Title: Quantum gravity corrections to the spontaneous excitation of an accelerated atom interacting with a quantum scalar fieldSubjects: High Energy Physics - Phenomenology (hep-ph); General Relativity and Quantum Cosmology (gr-qc); Quantum Physics (quant-ph)
The Generalized Uncertainty Principle (GUP) extends the Heisenberg Uncertainty Principle by suggesting a minimum observable scale that includes the effects of quantum gravity, which is supposed to potentially result in observable effects far below the Planck energy scale, providing us the opportunity to explore the theory of quantum gravity through physical processes at low energy scale. In present work, we study the corrections induced by the GUP to the spontaneous radiation properties of a two-level atom interacting with a real massless scalar quantum field based on the DDC formalism. The GUP alters the correlation function of the scalar field, consequently affecting the radiative properties of atoms. We compute the rate of change in the mean atomic energy for an atom undergoing inertial motion, uniform acceleration, and uniform circular motion. We show that the GUP can enhance the spontaneous emission rate of an excited state atom in inertial motion; however, it does not alter the stability of the ground-state atom in vacuum. For an atom in uniformly accelerated and uniformly circular motion, the GUP can change both its spontaneous emission and spontaneous excitation rates, and the proper acceleration $a$ can significantly amplify the effect of the GUP on the spontaneous transition rates of the atom.
- [10] arXiv:2411.14041 [pdf, html, other]
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Title: Sensitivities to New Resonance Couplings to $W$-Bosons at the LHCComments: 22 pages, 2 tables, 11 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
We propose a search strategy at the HL-LHC for a new neutral particle $X$ that couples to $W$-bosons, using the process $p p \rightarrow W^{\pm} X (\rightarrow W^{+} W^{-})$ with a tri-$W$-boson final state. Focusing on events with two same-sign leptonic $W$-boson decays into muons and a hadronically decaying $W$-boson, our method leverages the enhanced signal-to-background discrimination achieved through a machine-learning-based multivariate analysis. Using the heavy photophobic axion-like particle (ALP) as a benchmark, we evaluate the discovery sensitivities on both production cross section times branching ratio $\sigma(p p \rightarrow W^{\pm} X) \times \textrm{Br}(X \rightarrow W^{+} W^{-})$ and the coupling $g_{aWW}$ for the particle mass over a wide range of 170-3000 GeV at the HL-LHC with center-of-mass energy $\sqrt{s} = 14$ TeV and integrated luminosity $\mathcal{L} = 3$ $\textrm{ab}^{-1}$. Our results show significant improvements in discovery sensitivity, particularly for masses above 300 GeV, compared to existing limits derived from CMS analyses of Standard Model (SM) tri-$W$-boson production at $\sqrt{s} = 13$ TeV. This study demonstrates the potential of advanced selection techniques in probing the coupling of new particles to $W$-bosons and highlights the HL-LHC's capability to explore the physics beyond the SM.
- [11] arXiv:2411.14044 [pdf, html, other]
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Title: Analysis of hidden-charm pentaquarks as triangle singularities via deep learningComments: Proceedings of the 10th International Conference on Quarks and Nuclear Physics (QNP 2024). 6 pages, 3 figures, 2 tablesSubjects: High Energy Physics - Phenomenology (hep-ph)
Identifying the nature of near-threshold enhancements is hindered by the limited resolution of experimental data leading to multiple conflicting interpretations. A prominent example of ambiguous line shape is the set of pentaquark signals observed by LHCb in 2019. Some of these signals can be interpreted as hadronic molecule, compact state, virtual state, or due to a kinematical triangle mechanism. In this work, we leverage the model-selection capability of deep neural networks to analyze and identify the nature of $P_{c\bar{c}}(4457)^+$. We trained a set of deep neural networks using line shapes with enhancements produced by triangle singularities and those produced by nearby poles. The training dataset for the triangle enhancements are generated by using a set of hadrons satisfying the required mass condition. The training line shapes for the pole-based classifications are generated using uniformized independent $S$-matrix poles configured to appear close to the relevant threshold. We found that, despite the presence of experimental uncertainties, the triangle mechanism is ruled out by the experimental data. The results also suggest that the data favor the pole-shadow pair interpretation for the $P_{c\bar{c}}(4457)^+$, which corresponds to a characteristic pole structure involving a resonance in a two-channel scattering system. Our result is consistent with the initial analysis done by LHCb favoring the Breit-Wigner fit over the triangle singularity. The present analysis offers an alternative approach to studying line shapes, supplementing the standard fitting methods.
- [12] arXiv:2411.14050 [pdf, other]
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Title: Investigating the universality of five-point QCD scattering amplitudes at high energyComments: 46 pages (main) + 14 pages (appendices & references), 9 figures, 2 tables; analytic results collected at this https URLSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
We investigate $2 \to 3$ QCD scattering amplitudes in multi-Regge kinematics, i.e. where the final partons are strongly ordered in rapidity. In this regime amplitudes exhibit intriguing factorisation properties which can be understood in terms of effective degrees of freedom called \emph{reggeons}. Working within the Balitsky/JIMWLK framework, we predict these amplitudes for the first time to next-to-next-to-leading logarithmic order, and compare against the limit of QCD scattering amplitudes in full colour and kinematics. We find that the latter can be described in terms of universal objects, and that the apparent non-universality arising at NNLL comes from well-defined and under-control contributions that we can predict. Thanks to this observation, we extract for the first time the universal vertex that controls the emission of the central-rapidity gluon, both in QCD and $N = 4$ super Yang-Mills.
- [13] arXiv:2411.14051 [pdf, html, other]
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Title: TeV Window to Grand Unification: Higgs's Light Color Triplet PartnerComments: 9 pagesSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex)
The color-triplet partner of the Higgs doublet, called a $T$-particle, is a universal feature of Grand Unification. It has been shown some time ago that this particle can be accessible for direct production in collider experiments. In this paper we point out that the $T$-particle represents a simultaneous low-energy probe of baryon number violation as well as of the origin of the neutrino mass, linking the mediation of proton decay with oscillations of the neutron into a sterile neutrino. We point out a triple correlation between its collider signatures, proton decay measurements and the searches for the magnetic resonance disappearance of free neutrons in cold neutron experiments. In this way, the $T$-particle can provide a diversity of correlated experimental windows into Grand Unification.
- [14] arXiv:2411.14091 [pdf, html, other]
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Title: Towards a precision calculation of $N_{\rm eff}$ in the Standard Model IV: Impact of positronium formationComments: 16 pages, 2 figures, 2 tablesSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We present in this work the first assessment of the previously unexplored effect of positronium formation on the value of the effective number of neutrino species in the Standard Model, $N_{\mathrm{eff}}^{\mathrm{SM}}$. We find that the expected impact on $N_{\mathrm{eff}}^{\mathrm{SM}}$ crucially depends on the temperature at which positronium equilibrates as well as the rate at which this equilibration happens. The dominant factor limiting the formation process is the melting of positronium at high temperatures driven by Debye screening of the electrostatic potential and scatterings with real photons. Using simple physical arguments, we estimate that positronium forms at temperatures around $50-80$ keV. If formation and equilibration were instantaneous, the resulting change in $N_{\mathrm{eff}}^{\mathrm{SM}}$ would be at most $|\Delta N_{\mathrm{eff}}| \sim 10^{-4}$, comparable to other uncertainties in the current benchmark value for $N_{\mathrm{eff}}^{\mathrm{SM}}$. A more gradual formation could however yield a larger change, necessitating in turn a more detailed investigation before we can conclusively neglect the effect of positronium formation on $N_{\mathrm{eff}}^{\mathrm{SM}}$.
- [15] arXiv:2411.14126 [pdf, html, other]
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Title: Indications for new scalar resonances at the LHC and a possible interpretationComments: 24 pages, 14 figure files, uses RevtexSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex)
There have been indications of several new resonances at the Large Hadron Collider (LHC). Two of them, at about 95 GeV and 650 GeV, have been indicated by more than one experiments and have reached statistical significance worthy of a serious investigation. Conservatively using only the numbers given by the experimental collaborations, we find combined global significances around 3$\sigma$ and 4$\sigma$ respectively for the 95 GeV and 650 GeV putative resonances. There are some more which may soon become very significant. We show that the data on only the 650 GeV resonance, assuming they stand the test of time, predict the existence of a doubly-charged scalar, and make the extensions of the scalar sector like those by gauge singlet scalars, the 2-Higgs doublet models or the Georgi-Machacek model, highly disfavored. We provide the readers with a minimalistic model that can explain all the indications. Such a model can also accommodate the hints of a singly charged scalar at about 375 GeV, and a doubly charged scalar at about 450 GeV, as found by both the major LHC Collaborations, the combined global significance for each of them being above $2.5\sigma$. Our analysis comes with the obvious caveat that the allowed parameter space that we find depends on the available data on all the new resonances, and may change in future.
- [16] arXiv:2411.14128 [pdf, other]
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Title: Exploration of new experimental strategies for the detection of ultralight dark matter : laboratory searches on ground and in spaceComments: PhD thesisSubjects: High Energy Physics - Phenomenology (hep-ph); General Relativity and Quantum Cosmology (gr-qc)
Ultralight dark matter (ULDM), as a class of low mass (< 1 eV) dark matter (DM) candidates, is a compelling alternative to historically dominant models such as WIMPs and has recently gained significant attention in the scientific community. In this thesis, we study various experimental schemes for the direct detection of ULDM, both on ground and in space. More precisely, we propose a theoretical modeling of current and futuristic experiments, and we derive an estimation of their respective sensitivity. We mainly concentrate on three distinct phenomenologies. The first one is the coupling between a DM U(1) field, known as the dark photon (DP), and electromagnetism, which induces a small electric field oscillating at the DP Compton frequency. We study how to detect this electric field using atoms inside a cavity and through dish antennas. The second main phenomenology considered in this thesis is the oscillation of rest mass and transition frequencies of atoms and test masses. These oscillations could be produced by the non-universal coupling of standard matter with a scalar ULDM candidate (dilaton or axion-like particle). We study how to detect such couplings in classical tests of the universality of free fall (UFF), atom interferometry and using LISA. Finally, we study the effect of vacuum birefringence and dichroism induced by the coupling between axions and photons, and how it could be detected with optical cavities, fibers, and LISA.
- [17] arXiv:2411.14206 [pdf, html, other]
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Title: Clarity through the Neutrino Fog: Constraining New Forces in Dark Matter DetectorsPablo Blanco-Mas, Pilar Coloma, Gonzalo Herrera, Patrick Huber, Joachim Kopp, Ian M. Shoemaker, Zahra TabriziComments: 11 pages, 4 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex)
The PANDAX-4T and XENONnT experiments present indications of Coherent Elastic Neutrino Nucleus Scattering (CE$\nu$NS) from ${}^{8}$B solar neutrinos at 2.6$\sigma$ and 2.7$\sigma$, respectively. This constitutes the first observation of the neutrino "floor" or "fog", an irreducible background that future dark matter searches in terrestrial detectors will have to contend with. Here, we first discuss the contributions from neutrino-electron scattering and from the Migdal effect in the region of interest of these experiments, and we argue that they are non-negligible. Second, we make use of the recent PANDAX-4T and XENONnT data to derive novel constraints on light scalar and vector mediators coupling to neutrinos and quarks. We demonstrate that these experiments already provide world-leading laboratory constraints on new light mediators in some regions of parameter space.
- [18] arXiv:2411.14234 [pdf, html, other]
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Title: Steering in Neutrino Oscillations with Non-Standard InteractionComments: 8 pages, 2 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
In this study, we analyze the influence of Non-Standard Interaction (NSI) on steering in three-flavor neutrino oscillations, with a focus on the NO$\nu$A and DUNE experimental setups. DUNE, having a longer baseline, exhibits a more pronounced deviation towards NSI in steering compared to NO$\nu$A. Within the energy range where DUNE's maximum flux appears, the steering value for DUNE shows a $21\%$ deviation from the Standard Model (SM) to NSI for normal ordering (NO), while for inverted ordering (IO), the steering value increases by approximately $15\%$ relative to the SM. We conduct a comparative analysis of nonlocality, steering, and entanglement. Additionally, we express steering in terms of three-flavor neutrino oscillation probabilities and explore the relationship between steering inequality and concurrence.
- [19] arXiv:2411.14255 [pdf, html, other]
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Title: A Brief Introduction to PACIAE 4.0An-Ke Lei, Zhi-Lei She, Yu-Liang Yan, Dai-Mei Zhou, Liang Zheng, Wen-Chao Zhang, Hua Zheng, Larissa V. Bravina, Evgeny E. Zabrodin, Ben-Hao SaSubjects: High Energy Physics - Phenomenology (hep-ph)
Parton And-hadron China Institute of Atomic Energy (PACIAE) is a multipurpose Monte Carlo event generator developed to describe a wide range of high-energy collisions, including lepton-lepton, lepton-hadron, lepton-nucleus, hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. It is built based on the PYTHIA program, and incorporates parton and hadron cascades to address the nuclear medium effects. PACIAE 4.0 is the new generation of PACIAE model surpassing the version 3.0. In PACIAE 4.0, the old fixed-format FORTRAN 77 code has been refactored and rewritten by the free-format modern Fortran and C++ languages. The C++-based PYTHIA 8.3 is interfaced in, while previous versions connected to the Fortran-based PYTHIA 6.4 only. Several improvements are also introduced, which enable PACIAE 4.0 to contain more physics and features to model the high-energy collisions. This is the first attempt to transition PACIAE from Fortran to C++.
- [20] arXiv:2411.14306 [pdf, html, other]
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Title: The nature of $\chi_{c1}\left(3872\right)$ and $T_{cc}^+\left(3875\right)$Comments: 8 pages, 3 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); High Energy Physics - Lattice (hep-lat)
Two decades ago the $\chi_{c1}\left(3872\right)$ was discovered in the hadron spectrum with two heavy quarks. The discovery fueled a surge in experimental research, uncovering dozens of so called XYZ exotics states lying outside the conventional quark model, as well as theoretical investigations into new forms of matter, such as quark-gluon hybrids, mesonic molecules, and tetraquarks, with the potential of disclosing new information about the fundamental strong force. Among the XYZs, the $\chi_{c1}\left(3872\right)$ and $T_{cc}^+\left(3875\right)$ stand out for their striking characteristics and unlashed many discussions about their nature. Here, we address this question using the Born--Oppenheimer Effective Field Theory (BOEFT) and show how QCD settles the issue of their composition. Not only we describe well the main features of the $\chi_{c1}\left(3872\right)$ and $T_{cc}^+\left(3875\right)$ but obtain also model independent predictions in the bottomonium sector. This opens the way to systematic applications of BOEFT to all XYZs.
- [21] arXiv:2411.14348 [pdf, html, other]
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Title: Neutrino Flavour Waves Through the Quantum Vacuum: A Theory of OscillationsComments: 24 pages, 4 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
We propose a theory for neutrino oscillations, in which the flavour neutrinos are treated as waves of massless particles propagating in a "refractive quantum vacuum" and obeying a relativistically covariant equation of motion. The difference in strength between weak interactions and mass-generating interactions is argued to allow for the production and detection of flavour neutrinos in weak interactions as massless particles. They experience the mass-generating interactions as coherent forward scattering in the Brout-Englert-Higgs vacuum, which induces macroscopically multi-refringent effects. The flavour neutrino wave is then found to have a universal effective refractive mass in vacuum and a unique group velocity for a given energy. The coherence of the wave is manifest throughout and, at every moment of the propagation, the energy of the waves is the same. The standard oscillation probability in vacuum is obtained and the effects of matter are incorporated in a natural way.
New submissions (showing 21 of 21 entries)
- [22] arXiv:2411.13636 (cross-list from hep-th) [pdf, html, other]
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Title: Cosmological Correlators at the Loop LevelComments: 47 pagesSubjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
Cosmological correlators encode rich information about physics at the Hubble scale and may exhibit characteristic oscillatory signals due to the exchange of massive particles. Although many 1-loop processes, especially those that break de Sitter (dS) boosts, can generate significant leading signals for various particle models in cosmological collider physics, the precise results for these correlators or their full signals remain unknown due to the lack of symmetry. In this work, we apply the method of partial Mellin-Barnes (PMB) representation to the calculation of cosmological correlators at the loop level. As a first step, we use the PMB representation to calculate four-point cosmological correlators with bubble topology. We find that both the nonlocal and local signals arise from the factorized part, validating the cutting rules proposed in previous work, and are free from UV divergence. Furthermore, the UV divergence originates solely from the background piece and can be manifestly canceled by introducing the appropriate counterterm, similar to the procedure in flat spacetime. We also demonstrate how to renormalize the 1-loop correlators in Mellin space. After a consistency check with known results for the covariant case, we provide new analytical results for the signals generated from a nontrivial dS-boost-breaking bubble.
- [23] arXiv:2411.13637 (cross-list from astro-ph.CO) [pdf, html, other]
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Title: Do Observations Prefer Thawing Quintessence?Comments: 12 pages, 8 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
In light of recent observations, we study evidence for thawing quintessence over a cosmological constant as dark energy, with emphasis on the effect of the choice of priors. Working with a parametrization for the equation of state parameter motivated by the theory, we find a preference for thawing quintessence compared to a bare cosmological constant {\it only} if we use priors which are heavily informed by the data itself. If we extend the priors to physically better motivated ranges, the evidence for thawing quintessence disappears.
- [24] arXiv:2411.14063 (cross-list from gr-qc) [pdf, html, other]
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Title: Probing dark matter halo profiles with multi-band observations of gravitational wavesComments: 13 pages, 5 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics of Galaxies (astro-ph.GA); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
In this paper, we evaluate the potential of multiband gravitational wave observations to constrain the properties of static dark matter spikes around intermediate-mass ratio inspirals. The influence of dark matter on the orbital evolution of the compact binary is incorporated as a correction to the inspiral Newtonian gravitational waveform. We show that the observations from the proposed space-based detector GWSat, sensitive within the deci-Hz frequency band, when combined with that of the third-generation ground-based detectors like the Einstein Telescope and Cosmic Explorer, will produce significantly improved error estimates for all parameters. In particular, our results demonstrate that the joint multiband approach substantially refines the bounds on the dark matter spike parameters-namely, the power-law index and spike density-by factors of approximately $10^6$ and $10^3$, respectively, compared to observations employing only third-generation gravitational wave detectors.
- [25] arXiv:2411.14127 (cross-list from hep-lat) [pdf, html, other]
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Title: Non-perturbative thermal QCD at very high temperatures: computational strategy and hadronic screening massesLeonardo Giusti, Davide Laudicina, Matteo Bresciani, Mattia Dalla Brida, Tim Harris, Michele Pepe, Pietro RescignoComments: arXiv admin note: substantial text overlap with arXiv:2410.12626Subjects: High Energy Physics - Lattice (hep-lat); High Energy Physics - Phenomenology (hep-ph)
We discuss a recently introduced strategy to study non-perturbatively thermal QCD up to temperatures of the order of the electro-weak scale, combining step scaling techniques and shifted boundary conditions. The former allow to renormalize the theory for a range of scales which spans several orders of magnitude with a moderate computational cost. Shifted boundary conditions remove the need for the zero temperature subtraction in the Equation of State. As a consequence, the simulated lattices do not have to accommodate two very different scales, the pion mass and the temperature, at the very same spacing. Effective field theory arguments guarantee that finite volume effects can be kept under control safely. With this strategy the first computation of the hadronic screening spectrum has been carried out over more than two orders of magnitude in the temperature, from $T\sim 1$ GeV up to $\sim 160$ GeV. This study is complemented with the first quantitative computation of the baryonic screening mass at next-to-leading order in the three-dimensional effective theory describing QCD at high temperatures. Both for the mesonic and the baryonic screening masses, the known leading behaviour in the coupling constant is found to be not sufficient to explain the non-perturbative data over the entire range of temperatures. These findings shed further light on the limited applicability of the perturbative approach at finite temperature, even at the electro-weak scale.
- [26] arXiv:2411.14146 (cross-list from hep-th) [pdf, html, other]
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Title: One Loop Thermal Effective ActionComments: 48 pagesSubjects: High Energy Physics - Theory (hep-th); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph)
We compute the one loop effective action for a Quantum Field Theory at finite temperature, in the presence of background gauge fields, employing the Heat-Kernel method. This method enables us to compute the thermal corrections to the Wilson coefficients associated with effective operators up to arbitrary mass dimension, which emerge after integrating out heavy scalars and fermions from a generic UV theory. The Heat-Kernel coefficients are functions of non-zero background `electric', `magnetic' fields, and Polyakov loops. A major application of our formalism is the calculation of the finite temperature Coleman-Weinberg potentials in effective theories, necessary for the study of phase transitions. A novel feature of this work is the systematic calculation of the dependence of Polyakov loops on the thermal factors of Heat-Kernel coefficients and the Coleman-Weinberg potential. We study the effect of Polyakov loop factors on phase transitions and comment on future directions in applications of the results derived in this work.
- [27] arXiv:2411.14176 (cross-list from gr-qc) [pdf, html, other]
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Title: Dark universe inspired by the Kaluza-Klein gravityComments: 13 pages, 4 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
We explore the potential implications of Kaluza-Klein (KK) gravity in unifying the dark sector of the Universe. Through dimensional reduction in KK gravity, the 5D spacetime framework can be reformulated in terms of a 4D spacetime metric, along with additional scalar and vector fields. From the 4D perspective, this suggests the existence of a tower of particle states, including KK gravitons with massive spin-0 and spin-1 states, in addition to the massless spin-2 gravitons of general relativity (GR). By assuming a minimal coupling between the self-interacting scalar field and the gauge field, a "mass" term emerges for the spin-1 gravitons. This, in turn, leads to long-range gravitational effects that could modify Newton's law of gravity through Yukawa-type corrections. We draw an analogy with superconductivity theory, where the condensation of a scalar field results in the emergence of massive spin-1 particles producing repulsive forces, along with an increase of the gravitational force due the correction to Newton's constant. Assuming an environment-dependent mass for the spin-1 graviton, near the galactic center the repulsive force from this spin-1 graviton is suppressed by an additional attractive component from Newton's constant corrections, resulting in a Newtonian-like, attraction-dominated effect. In the galaxy's outer regions, the repulsive force fades due to its short range, making dark matter appear only as an effective outcome of the dominant attractive corrections. This approach also explains dark matter's emergence as an apparent effects on cosmological scales while our model is equivalent to the scalar-vector-tensor gravity theory. Finally, we examine the impact of dark matter on the primordial gravitational wave (PGW) spectrum and show that it is sensitive to dark matter effects, providing an opportunity to test this theory through future GW observatories.
Cross submissions (showing 6 of 6 entries)
- [28] arXiv:2310.00586 (replaced) [pdf, html, other]
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Title: On the Observables of Renormalizable InteractionsComments: 9 pages, 1 figure, v4: Correction to the color factor in the top-quark loop. (As a result, the running of the Higgs mass became easier to observe.)Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
We reconsider the renormalization of scalar mass and point out that the quantum correction to the physical observable, as opposed to the bare parameter, of a renormalizable operator, is technically insensitive to ultraviolet physics and independent of the regularization scheme. It is expressed as the difference in the same quantities at different energy scales, maintaining the same asymptotics. Thus, any sensible regularization cancels out the divergences, including the quadratic ones, and yields the same finite corrections. To this end, we first show that the vacuum polarization of quantum electrodynamics is independent of the regularization scheme and a gauge-dependent quadratic divergence is canceled in the observable. We then calculate the quantum correction to the Higgs mass squared by the top-quark loop. It is again finite and regularization-scheme independent. For large external momentum, the correction of the pole mass-squared is dominated by power running, resulting in an order of 1 percent correction. In particular, the effect of heavy fields on the scalar mass correction is suppressed.
- [29] arXiv:2310.16710 (replaced) [pdf, html, other]
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Title: CP-like Symmetry with Discrete and Continuous Groups and CP Violation/RestorationComments: 50 pages, 1 figure, published versionJournal-ref: JHEP 10 (2024) 213Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
We study physical implications of general CP symmetry including CP-like symmetry. Various scattering amplitudes of CP asymmetry are calculated in CP-like symmetric models. We explicitly show that the CP-like transformation leads to a specific relation between different CP asymmetries. The resultant relation is similar to the one obtained in GUT baryogenesis and sphaleron processes, where we also obtain a required condition for generating particle number asymmetry in CP-like symmetric models. In addition, we propose a generalization of a CP-like transformation for continuous symmetry groups. Since the CP transformation is an outer automorphism, which depends on the internal symmetry group, it turns out that the physical CP and CP-like symmetries can be mutually converted through the spontaneous symmetry breaking (SSB) of the internal symmetry. We investigate properties of physical CP asymmetry in both CP and CP-like symmetric phases, and find that the spontaneous CP violation and restoration can be observed even in models with continuous groups. We demonstrate that CP-like symmetric models with continuous Lie groups can be naturally realized in physical CP symmetric models through the SSB.
- [30] arXiv:2311.09488 (replaced) [pdf, html, other]
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Title: Top quark flavor changing couplings at a muon colliderComments: 21 pagesJournal-ref: Adv.High Energy Phys. 2024 (2024) 2038180Subjects: High Energy Physics - Phenomenology (hep-ph)
There is growing interest in the development of a muon collider that would make it possible to produce lepton collisions at energies of several TeV. Among others, there can be significant contributions to electroweak gauge boson, Higgs boson and top quark physics. In this work we pay attention to the latter, in particular, effective flavor-changing (FC) top-quark interactions. We discuss the flavor changing $t \bar q$ ($q=u,c$) production processes that can be a good probe of the dimension-six top quark four-fermion and fermion-boson operators in the SMEFT. We consider all sixteen operators that can generate flavor-changing top quark couplings. After comparing with the current LHC bounds, we find potential limits three or four orders of magnitude stronger for four-fermion operators. Concerning fermion-boson couplings, for the tensor operators $Q_{uW}$ and $Q_{uB}$ we obtain the highest sensitivity. We also observe that the effective $W$ approximation (EWA) does not apply with $Q_{uB}$.
- [31] arXiv:2312.08045 (replaced) [pdf, html, other]
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Title: Theories Without Models: Uncontrolled Idealizations in Particle PhysicsSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th); History and Philosophy of Physics (physics.hist-ph)
The perturbative treatment of realistic quantum field theories, such as quantum electrodynamics, requires the use of mathematical idealizations in the approximation series for scattering amplitudes. Such mathematical idealisations are necessary to derive empirically relevant models from the theory. Mathematical idealizations can be either controlled or uncontrolled, depending on whether current scientific knowledge can explain whether the effects of the idealization are negligible or not. Drawing upon negative formal results in asymptotic analysis (failure of Borel summability) and renormalization group theory (failure of asymptotic safety), we argue that the mathematical idealizations applied in perturbative quantum electrodynamics should be understood as uncontrolled. This, in turn, leads to the problematic conclusion that such theories do not have theoretical models in the standard understanding of this term. The existence of unquestionable empirically successful theories without theoretical models has significant implications both for our understanding of the theory-model relationship in physics and the concept of empirical adequacy.
- [32] arXiv:2404.15136 (replaced) [pdf, html, other]
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Title: QCD topology and axion properties in an isotropic hot and dense mediumComments: 10 pages, 10 figures; accepted for publication in EPJCSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
We study the QCD topology and axion properties at finite temperature and chemical potential in the framework of the two-flavor Nambu$-$Jona-Lasinio model. We find that the behaviors of the two lowest cumulants of the QCD topological charge distribution and axion properties are highly sensitive to the critical behavior of the chiral phase transition. In particular, the topological susceptibility and the axion mass follow the response of the chiral condensate to temperature and chemical potential, showing that both quantities decrease monotonically with the increment of temperature and/or chemical potential. However, it is important to note that the normalized fourth cumulant behaves differently depending on the temperature. At low temperatures, it is a non-monotonic function of the chemical potential, while at high temperatures, it monotonically decreases. Additionally, its value invariably approaches the asymptotic value of $b_2^{\text {inst }}=-1/12$, predicted by the dilute instanton gas model. We also observe that with the increase in chemical potential at relatively low temperatures, the axion self-coupling constant exhibits a sharp peak around the critical point, which can even be more than twice its vacuum value. After that, the self-coupling drops sharply to a much lower value than its vacuum value, eventually approaching zero in the high chemical potential limit. The finding that the axion self-coupling constant is significantly enhanced in high-density environments near the chiral phase transition could lead to the creation or enhancement of an axion Bose-Einstein condensate in compact astrophysical objects.
- [33] arXiv:2406.17824 (replaced) [pdf, html, other]
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Title: Fully heavy tetraquark resonant states with different flavorsComments: 10 pages,7 figures,8 tables. arXiv admin note: text overlap with arXiv:2401.14899Journal-ref: Phys.Rev.D 110,034030 (2024)Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); High Energy Physics - Lattice (hep-lat)
We use the quark potential model to calculate the mass spectrum of the S-wave fully heavy tetraquark systems with different flavors, including the $ bc\bar b\bar c, bb\bar c\bar c, cc\bar c\bar b $ and $ bb\bar b\bar c $ systems. We employ the Gaussian expansion method to solve the four-body Schrödinger equation, and the complex scaling method to identify resonant states. The $ bc\bar b\bar c, bb\bar c\bar c, cc\bar c\bar b $ and $ bb\bar b\bar c $ resonant states are obtained in the mass regions of $ (13.2,13.5) $, $ (13.3,13.6) $, $ (10.0,10.3) $, $ (16.5,16.7) $ GeV, respectively. Among these states, the $ bc\bar b\bar c $ tetraquark states are the most promising ones to be discovered in the near future. We recommend the experimental exploration of the $ 1^{++} $ and $ 2^{++} $ $ bc\bar b\bar c $ states with masses near $ 13.3 $ GeV in the $ J/\psi\Upsilon $ channel. From the root-mean-square radii, we find that all the resonant states we have identified are compact tetraquark states.
- [34] arXiv:2407.11653 (replaced) [pdf, html, other]
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Title: Particle Conversions Beyond the WKB Approximation and Solar-Induced Gravitational Waves from Dark Photon Dark MatterComments: 17 pages, 5 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
We investigate the conversion of kinetic mixing dark photon dark matter into gravitational waves within the magnetic field of the Sun. Our study reveals that the WKB approximation is invalid in this scenario. We derive an analytic solution for the conversion probability with unitary evolution feature. This solution aligns in form with previous studies on photon-gravitational wave conversion. Interestingly, it is applicable in situations where the WKB approximation fails. We extend the unitary evolution solution to other conversion processes, such as axion-photon and dark photon-photon conversions. When the WKB approximation conditions are met, this solution reduces to the WKB result. We compute the characteristic strain of gravitational waves resulting from dark photon conversion in the solar magnetic field, spanning frequencies from $10^{-5}$ Hz to $10^6$ Hz. Our findings indicate that the characteristic strain derived from the unitary evolution solution differs significantly from that of the WKB solution. The resulting strain signal is far below the sensitivity of current gravitational wave interferometers. Nevertheless, we have proposed an exotic gravitational wave source, which could be useful in non-minimal dark sector models.
- [35] arXiv:2407.16806 (replaced) [pdf, html, other]
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Title: Discovery Potential of Future Electron-Positron Colliders for a 95 GeV ScalarPramod Sharma, Anza-Tshilidzi Mulaudzi, Karabo Mosala, Thuso Mathaha, Mukesh Kumar, Bruce Mellado, Andreas Crivellin, Maxim Titov, Manqi Ruan, Yaquan FangComments: 10 pages, 7 captioned figures, 1 TableSubjects: High Energy Physics - Phenomenology (hep-ph)
The Large Electron Positron collider observed an indication for a new Higgs boson with a mass around $95$\,GeV-$100$\,GeV in the process $e^+e^-\to Z^*\to ZS$ with $S\to b\bar b$. The interest in this excess re-emerged with the di-photon signature at $\approx$\,95\,GeV at the Large Hadron Collider. In fact, a combined global significance of $3.4\sigma$ is obtained once $WW$ and $\tau\tau$ signals are included in addition. In this article, we perform a feasibility study for discovering such a new scalar $S$ at future electron-positron colliders using the recoil-mass method applied to $e^{+} e^{-} \to ZS$ with $Z \rightarrow \mu^{+} \mu^{-}$ and $S \to b \bar{b}$. For this, we employ a Deep Neural Network to enhance the separation between the Standard Model background and the signal, reducing the required integrated luminosity necessary for discovery by a factor of two to three. As a result, an $SU(2)_L$ singlet Higgs with a mass of $\approx$\,95\,GeV can be observed with more than 5$\sigma$ significance at a 250\,GeV centre-of-mass energy collider with $5~ {\rm ab}^{-1}$ integrated luminosity if it has a mixing angle of at least $0.1$ with the Standard Model Higgs, which means that a discovery can be achieved within the whole 95\% confidence-level region preferred by Large Electron Positron excess. Furthermore, including more decay channels such as $S\to \tau\tau$ and $Z\to e^+e^-$ further enhances the discovery potential of future $e^+e^-$ accelerators, like CEPC, CLIC, FCC-ee and ILC.
- [36] arXiv:2408.04511 (replaced) [pdf, html, other]
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Title: Dirac Algebra Formalism for Two Higgs Doublet Models: the One-Loop Effective PotentialComments: 18 pages, further clarifications added, results generalised after lifting the constraint on ζ^2, to appear in Physics Letters BSubjects: High Energy Physics - Phenomenology (hep-ph)
We present a novel covariant bilinear formalism for the Two Higgs Doublet Model (2HDM) which utilises the Dirac algebra associated with the SL(2,C) group that acts on the scalar doublet field space. This Dirac-algebra approach enables us to obtain a fully O(1,3)-covariant and IR-safe expression for the one-loop effective potential. We illustrate how the formalism can be used to evaluate the breaking of global symmetries of the 2HDM potential by loop effects, in a field-reparameterisation invariant manner.
- [37] arXiv:2409.00241 (replaced) [pdf, html, other]
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Title: Investigation of the semileptonic decay $ \Xi^{++}_{cc}\rightarrow \Xi^+_{c} \bar{\ell}\nu_{\ell}$ within QCD sum rulesComments: 17 Pages, 6 Figures and 4 TablesSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); High Energy Physics - Lattice (hep-lat)
We study the semileptonic decay of the doubly heavy baryon $ \Xi^{++}_{cc} $ into the singly heavy baryon $ \Xi^+_{c}$ within the three-point QCD sum rule approach in two possible lepton channels. Our analysis includes perturbative as well as nonperturbative condensation contributions up to dimension 5. We evaluate the form factors of this semileptonic decay entering the amplitude described by the vector and axial vector transition currents. The fit functions of the form factors with respect to the transferred momentum squared are utilized to predict the decay widths and branching ratios of the $ \Xi^{++}_{cc}\rightarrow \Xi^+_{c} \bar{\ell}\nu_{\ell}$ channels. We compare our findings with other predictions in the literature. Our outcomes can be useful for experimental groups in their search for the weak decays of doubly heavy baryons and may be checked via future experiments such as LHCb.
- [38] arXiv:2409.03373 (replaced) [pdf, html, other]
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Title: Doubly heavy tetraquark bound and resonant statesComments: 17 pages, 13 figures, version accepted by PRDJournal-ref: PhysRevD.110.094041 (2024)Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); High Energy Physics - Lattice (hep-lat); Nuclear Theory (nucl-th)
We calculate the energy spectrum of the S-wave doubly heavy tetraquark systems, including the $ QQ^{(\prime)}\bar q\bar q$, $QQ^{(\prime)}\bar s\bar q$, and $ QQ^{(\prime)}\bar s\bar s$ ($Q^{(\prime)}=b,c$ and $q=u,d$) systems within the constituent quark model. We use the complex scaling method to obtain bound states and resonant states simultaneously, and the Gaussian expansion method to solve the complex-scaled four-body Schrödinger equation. With a novel definition of the root-mean-square radii, we are able to distinguish between meson molecules and compact tetraquark states. The compact tetraquarks are further classified into three different types with distinct spatial configurations: compact even tetraquarks, compact diquark-antidiquark tetraquarks and compact diquark-centered tetraquarks. In the $ I(J^P)=0(1^+) $ $QQ\bar q\bar q$ system, there exists the $ D^*D $ molecular bound state with a binding energy of $ -14 $ MeV, which is the candidate for $ T_{cc}(3875)^+ $. The shallow $\bar B^*\bar B$ molecular bound state is the bottom analog of $T_{cc}(3875)^+$. Moreover, we identify two resonant states near the $D^*D^*$ and $\bar B^*\bar B^*$ thresholds. In the $ J^P=1^+ $ $bb\bar q\bar q\,(I=0)$ and $bb\bar s\bar q$ systems, we obtain deeply bound states with a compact diquark-centered tetraquark configuration and a dominant $\chi_{\bar 3_c\otimes 3_c}$ component, along with resonant states with similar configurations as their radial excitations. These states are the QCD analog of the helium atom. We also obtain some other bound states and resonant states with ``QCD hydrogen molecule" configurations. Moreover, we investigate the heavy quark mass dependence of the $ I(J^P)=0(1^+) $ $ QQ\bar q\bar q $ bound states. We strongly urge the experimental search for the predicted states.
- [39] arXiv:2409.05428 (replaced) [pdf, html, other]
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Title: Strong decays of the fully-charm tetraquark states with explicit P-waves via the QCD sum rulesComments: 12 pages, 2 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
We introduce a relative P-wave to construct the vector doubly-charm diquark $(\widetilde{V})$, therefore, the scalar and tensor tetraquark currents to investigate the decay widths of the fully-charm tetraquark states with the $J^{PC}=0^{++}$, $1^{+-}$ and $2^{++}$ via the QCD sum rules. We observe that the total width of the ground state $\widetilde{V}\overline{\widetilde{V}}$-type scalar tetraquark state is compatible with that of the $X(6552)$ within the range of uncertainties, and the branching ratios are quite different from that of the first radial excitation of the $A\bar{A}$-type scalar tetraquark state. Other predictions can be verified in the future experiments to shed light on the nature of the fully-charm tetraquark states.
- [40] arXiv:2409.07235 (replaced) [pdf, html, other]
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Title: Phenomenological model for the $\gamma^*\gamma \to \eta \pi^+ \pi^-$ reaction in the $f_1(1285)$ energy regionComments: 10 pages, 6 figures, 1 table, version to appear in Phys. Rev. DSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); Nuclear Theory (nucl-th)
Motivated by the ongoing analysis by the BESIII Collaboration on the single-tagged $e^+e^-\to e^+e^- \eta \pi^+\pi^-$ reaction, we present a phenomenological study of the diphoton fusion to $\eta \pi^+ \pi^-$, focusing on the production mechanism of the $f_1(1285)$ resonance. Contributions from the $f_1(1285)\to a_0(980)^\pm\, \pi^\mp$ and $f_1(1285)\to \sigma/f_0(500)\, \eta$ channels are included without introducing free parameters within an effective Lagrangian approach. Assuming the destructive interference between the amplitudes, we predict the invariant mass distributions, angular distributions, and total cross sections of the $\gamma^*\gamma \to \eta\pi^+\pi^-$ process, which will be tested by the forthcoming BESIII measurements.
- [41] arXiv:2409.16417 (replaced) [pdf, other]
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Title: KrkNLO matching for colour-singlet processesComments: 40 pages, 11 figures. Additional discussion of the NLO matching condition. Version accepted for publication by JHEPSubjects: High Energy Physics - Phenomenology (hep-ph)
Matched calculations combining perturbative QCD with parton showers are an indispensable tool for LHC physics. Two methods for NLO matching are in widespread use: MC@NLO and POWHEG. We describe an alternative, KrkNLO, reformulated to be easily applicable to any colour-singlet process. The primary distinguishing characteristic of KrkNLO is its use of an alternative factorisation scheme, the 'Krk' scheme, to achieve NLO accuracy. We describe the general implementation of KrkNLO in Herwig 7, using diphoton production as a test process. We systematically compare its predictions to those produced by MC@NLO with several different choices of shower scale, both truncated to one-emission and with the shower running to completion, and to ATLAS data from LHC Run 2.
- [42] arXiv:2409.20045 (replaced) [pdf, html, other]
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Title: Bubble wall velocity from number density current in (non)equilibriumComments: v2, 43 pages, 7 figures, major revision, a proof is added for the collision integral to vanish in local dynamical equilibrium, the necessity is introduced for the scalar-wall contribution to the total number density current, the clarification is emphasized for the conservation and violation of total number density current across the shock front and bubble wall, respectivelySubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
Cosmological first-order phase transitions (FOPTs) serve as comprehensive probes into our early Universe with associated generations of stochastic gravitational waves and superhorizon curvature perturbations or even primordial black holes. In characterizing the FOPT, phenomenological parameters like transition temperatures, strength factors, bubble separations, and energy budgets can be easily extracted from the macroscopic equilibrium features of the underlying particle physics models except for the terminal wall velocity of the bubble expansion, making it the last key parameter to be determined most difficultly due to the non-equilibrium nature of the microscopic transition model. In this paper, we propose a new model-independent approach to calculate the bubble wall velocity by virtue of an extra junction condition from the conservation and violation of the total number density current across the shock front (if any) and bubble wall, respectively.
- [43] arXiv:2405.08714 (replaced) [pdf, html, other]
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Title: On Holographic Vacuum MisalignmentComments: 49 pages, 5 figures; Version accepted for publicationSubjects: High Energy Physics - Theory (hep-th); High Energy Physics - Lattice (hep-lat); High Energy Physics - Phenomenology (hep-ph)
We develop a bottom-up holographic model that provides the dual description of a strongly coupled field theory, in which the spontaneous breaking of an approximate global symmetry yields the SO(5)/SO(4) coset relevant to minimal composite-Higgs models. The gravity background is completely regular and smooth, and has an end of space that mimics confinement on the field theory side. We add to the gravity description a set of localised boundary terms, that introduce additional symmetry-breaking effects, capturing those that would result from coupling the dual strongly coupled field theory to an external, weakly coupled sector. Such terms encapsulate the gauging of a subgroup of the global $SO(5)$ symmetry of the dual field theory, as well as additional explicit symmetry-breaking effects. We show how to combine spurions and gauge fixing and how to take the appropriate limits, so as to respect gauge principles and avoid violations of unitarity.
The interplay of bulk and boundary-localised couplings leads to the breaking of the SO(5) symmetry to either its SO(4) or SO(3) subgroup, via vacuum misalignment. In field theory terms, the model describes the spontaneous breaking of a SO(4) gauge symmetry to its SO(3) subgroup. We expose the implications of the higgsing phenomenon by computing the spectrum of fluctuations of the model, which we interpret in four-dimensional field-theory terms, for a few interesting choices of parameters. We conclude by commenting on the additional steps needed to build a realistic composite Higgs model. - [44] arXiv:2406.20009 (replaced) [pdf, html, other]
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Title: Lanczos, the transfer matrix, and the signal-to-noise problemComments: Improved spurious eigenvalue filtering, analysis of large-iteration behavior, presentation, and comparison with multi-state fitsSubjects: High Energy Physics - Lattice (hep-lat); High Energy Physics - Phenomenology (hep-ph); Nuclear Theory (nucl-th)
This work introduces a method for determining the energy spectrum of lattice quantum chromodynamics (LQCD) by applying the Lanczos algorithm to the transfer matrix and using a bootstrap generalization of the Cullum-Willoughby method to filter out spurious eigenvalues. Proof-of-principle analyses of the simple harmonic oscillator and the LQCD proton mass demonstrate that this method provides faster ground-state convergence than the "effective mass," which is related to the power-iteration algorithm. Lanczos provides more accurate energy estimates than multi-state fits to correlation functions with small imaginary times while achieving comparable statistical precision. Two-sided error bounds are computed for Lanczos results and guarantee that excited-state effects cannot shift Lanczos results far outside their statistical uncertainties. Further, Lanczos results avoid the exponential signal-to-noise degradation present in he power-iteration method / effective mass.
- [45] arXiv:2407.13823 (replaced) [pdf, html, other]
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Title: Schwinger vs Coleman: Magnetic Charge RenormalizationComments: 40 pages plus appendices, 12 figuresJournal-ref: Journal of High Energy Physics (2024) 1-49Subjects: High Energy Physics - Theory (hep-th); High Energy Physics - Phenomenology (hep-ph)
The kinetic mixing of two U(1) gauge theories can result in a massless photon that has perturbative couplings to both electric and magnetic charges. This framework can be used to perturbatively calculate in a quantum field theory with both kinds of charge. Here we re-examine the running of the magnetic charge, where the calculations of Schwinger and Coleman sharply disagree. We calculate the running of both electric and magnetic couplings and show that the disagreement between Schwinger and Coleman is due to an incomplete summation of topological terms in the perturbation series. We present a momentum space prescription for calculating the loop corrections in which the topological terms can be systematically separated for resummation. Somewhat in the spirit of modern amplitude methods we avoid using a vector potential and use the field strength itself, thereby trading gauge redundancy for the geometric redundancy of Stokes surfaces. The resulting running of the couplings demonstrates that Dirac charge quantization is independent of renormalization scale, as Coleman predicted. As a simple application we also bound the parameter space of magnetically charged states through the experimental measurement of the running of electromagnetic coupling.
- [46] arXiv:2408.13107 (replaced) [pdf, html, other]
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Title: Quarkyonic equation of state with a momentum dependent interaction and neutron star structureComments: 9 pages, 10 figures, 1 table. Comments are welcomeJournal-ref: Nuclear Physics A 1054 (2025) 122982Subjects: Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
The structure and basic properties of dense nuclear matter still remain one of the open problems of Physics. In particular, the composition of the matter that composes neutron stars is under theoretical and experimental investigation. Among the theories that have been proposed, apart from the classical one where the composition is dominated by hadrons, the existence or coexistence of free quark matter is a dominant guess. An approach towards this solution is the phenomenological view according to which the existence of quarkyonic matter plays a dominant role in the construction of the equation of state (EOS). According to it the structure of the EOS is based on the existence of the quarkyonic particle which is a hybrid state of a particle that combines properties of hadronic and quark matter with a corresponding representation in momentum space. In this paper we propose a phenomenological model for quarkyonic matter, borrowed from corresponding applications in hadronic models, where the interaction in the quarkyonic matter depends not only on the position but also on the momentum of the quarkyonic particles. This consideration, as we demonstrate, can have a remarkable consequence on the shape of the EOS and thus on the properties of neutron stars, offering a sufficiently flexible model. Comparison with recent observational data can place constraints on the parameterization of the particular model and help improve its reliability.
- [47] arXiv:2408.16283 (replaced) [pdf, html, other]
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Title: Premerger phenomena in neutron-star binary coalescencesComments: 53 pages, 22 figures, 4 tables. To appear as an invited review for a special issue of Universe (Feature Papers 2024 - Compact Objects; Ed. N. Chamel)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
A variety of high-energy events can take place in the seconds leading up to a binary neutron-star merger. Mechanisms involving tidal resonances, electrodynamic interactions, or shocks in mass-loaded wakes have been proposed as instigators of these precursors. With a view of gravitational-wave and multimessenger astrophysics more broadly, premerger observations and theory are reviewed emphasising how gamma-ray precursors and dynamical tides can constrain the neutron-star equation of state, thermodynamic microphysics, and evolutionary pathways. Connections to post-merger phenomena, notably gamma-ray bursts, are discussed together with how magnetic fields, spin and misalignment, crustal elasticity, and stratification gradients impact observables.