Nuclear Experiment
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Showing new listings for Friday, 22 November 2024
- [1] arXiv:2411.14337 [pdf, html, other]
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Title: Scaling Properties of ${\phi}$-Meson and Light Charged Hadron Production in Small and Large Systems at PHENIXRachid Nouicer (for the PHENIX Collaboration)Comments: Submitted to European Physics Journal (EPJ) Web of Conferences, The International Conference on Strangeness in Quark Matter (SQM 2024)Subjects: Nuclear Experiment (nucl-ex)
Recent results on the identified charged-hadron ($\pi^\pm$, $K^\pm$, $p$, $\bar{p}$) production at midrapidity region ($|\eta|<$ 0.35) have been measured by the PHENIX experiment in ${\rm {\it p}+Al}$, ${\rm ^{3}He+Au}$, ${\rm Cu+Au}$ collisions at $\sqrt{s_{_{NN} }}$ = 200 GeV and ${\rm U+U}$ collisions at $\sqrt{s_{_{NN} }}$ = 193 GeV. These measurements are presented through the invariant transverse-momentum ($p_T$) and transverse-mass ($m_T$) spectra for different collision centralities. The averaged freeze-out temperature value for different systems was found to be $166.1 \pm 2.2$ MeV, and do not exhibit any dependence on the collision centrality and $\langle N_{\rm part} \rangle$ values. The particle ratios of $K/\pi$ and $p/\pi$ have been measured in different centrality ranges of large and small collision systems. The values of $K/\pi$ ratios measured in all considered collision systems were found to be consistent with those measured in $p$$+$$p$ collisions. Furthermore, the identified charged-hadron nuclear-modification factors ($R_{AB}$) are also presented. Enhancement of proton $R_{AB}$ values over meson $R_{AB}$ values was observed in central ${\rm ^{3}He+Au}$, ${\rm Cu+Au}$, and ${\rm U+U}$ collisions. The proton $R_{AB}$ values measured in ${\rm {\it p}+Al}$ collision system were found to be consistent with $R_{AB}$ values of $\phi$, $\pi^\pm$, $K^\pm$, and $\pi^0$ mesons, suggesting that the size of the system produced in ${\rm {\it p}+Al}$ collisions is too small for recombination to cause a noticeable increase in proton production.
- [2] arXiv:2411.14355 [pdf, html, other]
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Title: Measurement of two-neutrino double electron capture half-life of $^{124}$Xe with PandaX-4TPandaX Collaboration: Zihao Bo, Wei Chen, Xun Chen, Yunhua Chen, Zhaokan Cheng, Xiangyi Cui, Yingjie Fan, Deqing Fang, Zhixing Gao, Lisheng Geng, Karl Giboni, Xunan Guo, Xuyuan Guo, Zichao Guo, Chencheng Han, Ke Han, Changda He, Jinrong He, Di Huang, Houqi Huang, Junting Huang, Ruquan Hou, Yu Hou, Xiangdong Ji, Xiangpan Ji, Yonglin Ju, Chenxiang Li, Jiafu Li, Mingchuan Li, Shuaijie Li, Tao Li, Zhiyuan Li, Qing Lin, Jianglai Liu, Congcong Lu, Xiaoying Lu, Lingyin Luo, Yunyang Luo, Wenbo Ma, Yugang Ma, Yajun Mao, Yue Meng, Xuyang Ning, Binyu Pang, Ningchun Qi, Zhicheng Qian, Xiangxiang Ren, Dong Shan, Xiaofeng Shang, Xiyuan Shao, Guofang Shen, Manbin Shen, Wenliang Sun, Yi Tao, Anqing Wang, Guanbo Wang, Hao Wang, Jiamin Wang, Lei Wang, Meng Wang, Qiuhong Wang, Shaobo Wang, Siguang Wang, Wei Wang, Xiuli Wang, Xu Wang, Zhou Wang, Yuehuan Wei, Weihao Wu, Yuan Wu, Mengjiao Xiao, Xiang Xiao, Kaizhi Xiong, Yifan Xu, Shunyu Yao, Binbin Yan, Xiyu Yan, Yong Yang, Peihua Ye, Chunxu Yu, Ying Yuan, Zhe Yuan, Youhui Yun, Xinning Zeng, Minzhen Zhang, Peng Zhang, Shibo Zhang, Shu Zhang, Tao Zhang, Wei Zhang, Yang Zhang, Yingxin Zhang, Yuanyuan Zhang, Li Zhao, Jifang Zhou, Jiaxu Zhou, Jiayi Zhou, Ning Zhou, Xiaopeng ZhouComments: 18 pages, 5 figures, 3 tablesSubjects: Nuclear Experiment (nucl-ex)
Detailed studies of two-neutrino double electron capture (2$\nu$DEC) is a crucial step towards searching for the neutrino-less mode to explore the Majorana nature of neutrinos. We have measured precisely the half-life of the 2$\nu$DEC process in $^{124}$Xe, utilizing a total exposure of 1.73 tonne$\cdot$year from the commissioning run and the first science run of the PandaX-4T experiment. A time-dependent background model in the $\mathcal{O}$(10 keV) energy is constructed for the first time in PandaX-4T data. With an unbinned maximum likelihood fit, we determine the half-life of the 2$\nu$DEC process to be $(1.03\pm0.15_{\rm stat}\pm0.06_{\rm sys})\times 10^{22}$$\,$yr. Furthermore, we have evaluated the branching ratio for both electrons captured from the $K$ shell ($KK$) to be $(65\pm5)\%$, which aligns with the $^{124}$Xe nuclear model calculations within 1.5$\,$$\sigma$.
New submissions (showing 2 of 2 entries)
- [3] arXiv:2411.13622 (cross-list from nucl-th) [pdf, html, other]
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Title: Probing small neutron skin variations in isotope pairs by hyperon-antihyperon production in antiproton--nucleus interactionsFalk Schupp, Josef Pochodzalla, Michael Bölting, Martin Christiansen, Theodoros Gaitanos, Horst Lenske, Marcell SteinenComments: 9 figuresSubjects: Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
We propose a new method to measure the evolution of the neutron skin thickness between different isotopes with small statistical and systematic uncertainties. We consider antiproton--nucleus interactions close to the production threshold of $\Lambda \overline{\Lambda }$ and $\Sigma^-\overline{\Lambda }$ pairs. At low energies, $\Lambda \overline{\Lambda }$ pairs are produced in $\overline{\text{p}} +\text{p}$ collisions, while $\Sigma^-\overline{\Lambda }$ pairs can only be produced in $\overline{\text{p}} +\text{n}$ interactions. Within a simple geometrical picture we show that the double ratio for the production of $\Sigma^-\overline{\Lambda }$ and $\Lambda \overline{\Lambda }$ pairs for two different isotopes are directly related to the variation of the neutron skin thickness between the two nuclei. Performing high statistics calculations with the Gießen Boltzmann--Uehling--Uhlenbeck (GiBUU) transport model for several isotope pairs covering a wide range of elements we verify a strong correlation between the double ratio from the full transport simulations and the schematic model. This correlation enables us to quantify the high potential of the proposed method for precise studies of neutron skin variations in isotope chains.
- [4] arXiv:2411.13845 (cross-list from hep-ph) [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.
- [5] arXiv:2411.13963 (cross-list from nucl-th) [pdf, html, other]
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Title: Proton-neutron pair correlations in neutron-rich nucleiComments: 8 pages, 5 figuresSubjects: Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
[Background] Nuclear pairing is a well-established many-body correlation, particularly among like particles in a spin-singlet state. However, the strength of spin-triplet proton-neutron (pn) pairing in nuclei has remained a long-standing and unresolved issue. [Purpose] The relative strength of spin-triplet pn pairing compared to spin-singlet one is investigated by introducing and analyzing the polarizability of the response to pn pair transfers. [Method] The nuclear energy-density functional method is employed. The ground state of the target nucleus is described using the Hartree-Fock-Bogoliubov approximation, which accounts for the conventional superfluidity of like-particle pairs. The response to pn pair transfers is then analyzed using the pn quasiparticle random-phase approximation. [Results] The spin-singlet pn-pair correlation is strongest at $N=Z$ and decreases monotonically with the increasing number of excess neutrons, whereas the spin-triplet pn-pair correlation is shown to depend non-monotonically on the neutron number and can be enhanced in cases where the pn-pair transfers involving the $\pi j_> \otimes \nu j_<$ configuration occur at low energy. [Conclusions] The shell effect, which uniquely appears in spin-triplet pn-pair correlation, serves as a key indicator of the strength of pn-pair correlations.
- [6] arXiv:2411.14366 (cross-list from hep-ex) [pdf, other]
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Title: Direct-photon production in inelastic and high-multiplicity proton-proton collisions at $\sqrt{s} =$ 13 TeVComments: 27 pages, 6 captioned figures, authors from page 21, submitted to PLB, figures at this http URLSubjects: High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex)
In this letter, we present the first measurement of direct photons at the transverse momentum of $ 1 < p_{\rm T} < 6$ GeV/$c$ at midrapidity $|\eta| < 0.8$ in inelastic and high-multiplicity proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV. The fraction of virtual direct photons in the inclusive virtual photon spectrum is obtained from a fit to the dielectron invariant mass spectrum. In the limit of zero invariant mass, this fraction is equal to the relative contribution of real direct photons in the inclusive real photon spectrum. Contributions from decays of light-flavour neutral mesons are estimated using independent measurements in proton-proton collisions at the same energy and the same event class. The yield of direct photons in inelastic pp collisions is compared to perturbative QCD calculations. The integrated photon yield is studied as a function of charged-particle multiplicity and is compared to the results from other experiments and theoretical calculations. The results show a significant increase of direct-photon yield with charged-particle multiplicity.
Cross submissions (showing 4 of 4 entries)
- [7] arXiv:2410.00389 (replaced) [pdf, html, other]
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Title: Precise Mass Measurement of the Longest Odd-Odd Chain of \boldmath $1^+$ Ground StatesB. Liu, M. Brodeur, J.A. Clark, I. Dedes, J. Dudek, F. G. Kondev, D. Ray, G. Savard, A.A. Valverde, D.P. Burdette, A.M. Houff, R. Orford, W.S. Porter, F. Rivero, K.S. Sharma, L. VarrianoSubjects: Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
Precise mass measurements of the odd-odd $^{108, 110, 112, 114, 116}$Rh ground and isomeric states were performed using the Canadian Penning Trap at Argonne National Laboratory, showing a good agreement with recent JYFLTRAP measurements. A new possible isomeric state of $^{114}$Rh was also observed. These isotopes are part of the longest odd-odd chain of identical ground state spin-parity assignment, of 1$^+$, spanning $^{104-118}$Rh, despite being in a region of deformation. Realistic phenomenological mean-field calculations using ``universal'' Wood-Saxon Hamiltonian were performed, explaining this phenomenon for the first time. In addition, multi-quasiparticle blocking calculations were conducted to study the configuration of low-lying states in the odd-odd Rh nuclei and elucidate the observed anomalous isomeric yield ratio of $^{114}$Rh.
- [8] arXiv:2410.02473 (replaced) [pdf, html, other]
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Title: Simulating collectivity in dense baryon matter with multiple fluidsComments: Proceedings of SQM2024, Strasbourg (France), 3-7 June 2024. 4 pages, 3 figures. v2: version accepted for the publicationSubjects: Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
We report on construction of a modern multi-fluid approach to heavy-ion collisions at FAIR/BES energies (MUFFIN) and show the reproduction of basic experimental observables in Au-Au collisions in the RHIC Beam Energy Scan program. We also show the $p_T$-differential and $p_T$-integrated polarization of (anti-)$\Lambda$ hyperons. In MUFFIN simulations, we observe a strong splitting between polarizations of $\Lambda$ and anti-$\Lambda$. The splitting is driven purely by a finite baryon chemical potential.