Tue·Dec 26, 2023Tuesday·December 26, 2023

1. 01*

   Measurements of ${\Lambda }_{\mathrm{c}}^{+}/{\mathrm{D}}^0$ ratio as a function of multiplicity at midrapidity at $\sqrt{s_{\text{NN}}}=5.02\text{TeV}$

   Oveis Sheibani (on behalf of ALICE collaboration)🇺🇸

   In this contribution, the measurement of prompt ${\Lambda }_{\mathrm{c}}^{+}/{\mathrm{D}}^0$ ratio as a function of multiplicity in p--Pb collisions at mid-rapidity at $\sqrt{s_{\text{NN}}}=5.02\text{TeV}$ is discussed. By performing this measurement as a function of multiplicity in pp and p--Pb collisions, we can evaluate the $p_{\mathrm{T}}$-differential baryon to meson enhancement and compare them to results in ${\mathrm{e}}^{-}{\mathrm{e}}^{+}$ and ${\mathrm{e}}^{-}\mathrm{p}$ collisions, where lower ${\Lambda }_{\mathrm{c}}^{+}/{\mathrm{D}}^0$ ratios at low and intermediate $p_{\mathrm{T}}$ have been observed, with the origin of this different behavior being still debated. In these measurements, we aim to compare the p--Pb results to pp collisions to investigate the possible effects of cold nuclear matter on charm-baryon production, and to Pb--Pb collisions for investigating the impact of quark--gluon plasma on charm quark hadronization.

   nucl-exhep-exhep-ph2 citations
2. 02*

   Searching for Two-Neutrino and Neutrinoless Double Beta Decay of ${}^{134}$Xe with the PandaX-4T Experiment

   PandaX Collaboration: Xiyu Yan🇨🇳 · Zhaokan Cheng🇨🇳 · Abdusalam Abdukerim🇨🇳 · Zihao Bo🇨🇳 · Wei Chen🇨🇳 · Xun Chen🇨🇳 · Chen Cheng🇨🇳 · Xiangyi Cui🇨🇳 · Yingjie Fan🇨🇳 · Deqing Fang🇨🇳 · Changbo Fu🇨🇳 · Mengting Fu🇨🇳 and 84 other authors

   ${}^{134}$Xe is a candidate isotope for neutrinoless double beta decay~($0\nu \beta \beta$) search. In addition, the two-neutrino case ($2\nu \beta \beta$) allowed by the Standard Model of particle physics has not yet been observed. Utilizing the 10.4% of ${}^{134}$Xe in the natural xenon in the PandaX-4T detector and its first 94.9-day exposure, we have established the most stringent constraints on $2\nu \beta \beta$ and $0\nu \beta \beta$ of ${}^{134}$Xe half-lives, with limits of $2.8\times 10^{22}$ yr and $3.0\times 10^{23}$ yr at 90% confidence level, respectively. The $2\nu \beta \beta$ ($0\nu \beta \beta$) limit surpasses the previously reported best result by a factor of 32 (2.7), highlighting the potential of large monolithic natural xenon detectors.

   nucl-exPRL(2024)·31 citations
3. 03*

   New Insights into Global Spin Alignment of Vector Mesons Using Relativistic Heavy-Ion Collisions from STAR

   Baoshan Xi🇨🇳

   In these proceedings, we present new measurements from STAR of the global spin alignment(${\rho }_{00}$) of $\varphi$ mesons in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 19.6, 14.6 GeV using BES-II data and of $J/\psi$ mesons in isobar collisions ${}_{44}^{96}\mathrm{Ru}+{}_{44}^{96}\mathrm{Ru}$ and ${}_{40}^{96}\mathrm{Zr}+{}_{40}^{96}\mathrm{Zr}$ at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV. The energy-dependent spin alignment for $\varphi$ mesons from BES-II data is consistent with that published from BES-I and showcases a significant improvement in precision. We performed a new measurement assessing the rapidity dependence of $\varphi$ meson ${\rho }_{00}$, and our findings are consistent with theoretical predictions. The global spin alignment of $J/\psi$ mesons with respect to first order event plane aligns with a value of $1/3$ within the statistical error. Additionally, we discuss the procedure of measuring the global spin alignment of ${\rho }^0$ mesons at RHIC and provide the projection for errors.

   nucl-exhep-exEPJ Web Conf.(2024)·1 citation
4. 04*

   Hypertriton Production in Au+Au Collisions from STAR BES-II

   Yuanjing Ji🇺🇸

   Hypernuclei are bound states of nuclei with one or more hyperons. Precise measurements of hypernuclei properties and their production yields in heavy ion collisions are crucial for the understanding of their production mechanisms. The second phase of the Beam Energy Scan at RHIC (BES-II) offers us a great opportunity to investigate collision energy and system size dependence of hypernuclei production. In these proceedings, we present new measurements on transverse momentum ($p_T$), rapidity (y), and centrality dependence of ${}_{\mathrm{\Lambda }}^3\mathrm{H}$ production yields in Au+Au collisions from $\sqrt{s_{NN}}$ = 3 to 7.7 GeV. These results are compared with phenomenological model calculations, and physics implications on the hypernuclei production mechanism are also discussed.

   nucl-exEPJ Web Conf.(2024)·2 citations
5. 05*

   A demonstrator for a real-time AI-FPGA-based triggering system for sPHENIX at RHIC

   J. Kvapil (1)🇺🇸 · G. Borca-Tasciuc (2)🇺🇸 · H. Bossi (3)🇺🇸 · K. Chen (4)🇨🇳 · Y. Chen (4)🇺🇸 · Y. Corrales Morales (3)🇺🇸 · H. Da Costa (1)🇺🇸 · C. Da Silva (1)🇺🇸 · C. Dean (3)🇺🇸 · J. Durham (1)🇺🇸 · S. Fu (5)🇺🇸 · C. Hao (6)🇺🇸 and 19 other authors

   The RHIC interaction rate at sPHENIX will reach around 3 MHz in pp collisions and requires the detector readout to reject events by a factor of over 200 to fit the DAQ bandwidth of 15 kHz. Some critical measurements, such as heavy flavor production in pp collisions, often require the analysis of particles produced at low momentum. This prohibits adopting the traditional approach, where data rates are reduced through triggering on rare high momentum probes. We explore a new approach based on real-time AI technology, adopt an FPGA-based implementation using a custom designed FELIX-712 board with the Xilinx Kintex Ultrascale FPGA, and deploy the system in the detector readout electronics loop for real-time trigger decision.

   ↳ physics.ins-dethep-exnucl-exJINST(2024)·1 citation
6. 06*

   Design and early operation of a new-generation internal beam dump for CERN's Super Proton Synchrotron

   A. Romero Francia🇨🇭 · A. Perillo Marcone🇨🇭 · S. Pianese🇨🇭 · K. Andersen🇨🇭 · G. Arnau Izquierdo🇨🇭 · J.A. Briz🇨🇭 · D. Carbajo Perez🇨🇭 · E. Carlier🇨🇭 · T. Coiffet🇨🇭 · L.S. Esposito🇨🇭 · J.L. Grenard🇨🇭 · D. Grenier🇨🇭 and 13 other authors

   The Super Proton Synchrotron (SPS) is the last stage in the injector chain for CERN's Large Hadron Collider, and it also provides proton and ion beams for several fixed-target experiments. The SPS has been in operation since 1976, and it has been upgraded over the years. For the SPS to operate safely, its internal beam dump must be able to repeatedly absorb the energy of the circulating beams without sustaining damage that would affect its function. The latest upgrades of the SPS led to the requirement for its beam dump to absorb proton beams with a momentum spectrum from 14 to 450~GeV/$c$ and an average beam power up to $\sim$270~kW. This paper presents the technical details of a new design of SPS beam dump that was installed in one of the long straight sections of the SPS during the 2019--2020 shutdown of CERN's accelerator complex. This new beam dump has been in operation since May 2021, and it is foreseen that it will operate with a lifetime of 20~years. The key challenges in the design of the beam dump were linked to the high levels of thermal energy to be dissipated -- to avoid overheating and damage to the beam dump itself -- and high induced levels of radiation, which have implications for personnel access to monitor the beam dump and repair any problems occurring during operation. The design process therefore included extensive thermomechanical finite-element simulations of the beam-dump core and its cooling system's response to normal operation and worst-case scenarios for beam dumping. To ensure high thermal conductivity between the beam-dump core and its water-cooling system, hot isostatic pressing techniques were used in its manufacturing process. A comprehensive set of instrumentation was installed in the beam dump to monitor it during operation and to cross-check the numerical models with operational feedback.

   ↳ physics.acc-phhep-exnucl-exphysics.ins-detPhys.Rev.Accel.Beams(2024)·4 citations
7. 07*

   The imprint of conservation laws on correlated particle production

   Peter Braun-Munzinger🇩🇪 · Krzysztof Redlich🇵🇱 · Anar Rustamov🇩🇪 · Johanna Stachel🇩🇪

   The study of event-by-event fluctuations of net-baryon number in a subspace of full phase space is a promising direction for deciphering the structure of strongly interacting matter created in head-on collisions of relativistic heavy nuclei. Such fluctuations are generally suppressed by exact baryon number conservation. Moreover, the suppression is stronger if baryon number is conserved locally. In this report we present a conceptually new approach to quantify correlations in rapidity space between baryon-antibaryon, baryon-baryon, and antibaryon-antibaryon pairs and demonstrate their impact on net-baryon number fluctuations. For the special case of Gaussian rapidity distributions, we use the Cholesky factorization of the covariance matrix, while the general case is introduced by exploiting the well-known Metropolis and Simulated Annealing methods. The approach is based on the use of the canonical ensemble of statistical mechanics for baryon number and can be applied to study correlations between baryons as well as strange and/or charm hadrons. It can also be applied to describe relativistic nuclear collisions leading to the production of multi-particle final states. One application of our method is the search for formation of proton clusters at low collision energies emerging as a harbinger of the anticipated first-order chiral phase transition. In a first step, the results obtained are compared to the recent measurements from the CERN ALICE collaboration. Such investigations are key to explore the phase diagram of strongly interacting matter and baryon production mechanisms at energy scales from several GeV to several TeV.

   ↳ nucl-thhep-phnucl-exJHEP(2024)·25 citations
8. 08*

   The $z_g$ distribution for heavy flavour jets in dense quark-gluon plasma

   Boris Blok (Technion)🇮🇱 · Chang Wu (Technion)🇮🇱

   We study the $z_g$ distribution for heavy flavour, i.e. bottom and charm quark, jets propagating through the dense QCD medium. We extend the late emission approximation for Armesto-Salgado-Wiedemann (ASW) formula to heavy flavours. % We consider both the normalised and $N_{\mathrm{jet}}$ normalised $z_g$ distributions, and the ratio of the latter distributions to the vacuum ones, called the R ratio. We demonstrate that since there is no collinear singularity in the medium, there is no principal need to use the Sudakov safety technique for medium-induced emission (MIE). We see that contrary to the vacuum case, the normalised $z_g$ distribution is sensitive to the dead cone angle value. In particular, for the case of $N_{jet}$ normalised distribution with ${\theta }_g\le {\theta }_{cut}$, it is possible to directly probe the dead cone gluons in the medium. Our results can be useful to guide the experimental measurements of the heavy flavour jet substructure in dense QCD medium.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2025)·6 citations
9. 09*

   Saturation of nuclear matter in the relativistic Brueckner Hatree-Fock approach with a leading order covariant chiral nuclear force

   Wei-Jiang Zou🇨🇳 · Jun-Xu Lu🇨🇳 · Peng-Wei Zhao🇨🇳 · Li-Sheng Geng🇨🇳 · Jie Meng🇨🇳

   Nuclear saturation is a crucial feature in nuclear physics that plays a fundamental role in understanding various nuclear phenomena, ranging from properties of finite nuclei to those of neutron stars. However, a proper description of nuclear saturation is highly nontrivial in modern nonrelativistic~\textit{ab initio}~studies because of the elusive three-body forces. In this letter, we calculate the equation of state for nuclear matter in the relativistic Brueckner-Hartree-Fock (RBHF) framework with the leading order covariant chiral nuclear force. We show that a simultaneous description of the nucleon-nucleon scattering data and the saturation of the symmetric nuclear matter can be achieved. In this regard, the relativistic effects nicely explain the saturation of nuclear matter. As a result, the present study based on the covariant chiral nuclear force shows that in the RBHF framework, one can achieve saturation with a leading order covariant chiral nuclear force with only two-body forces, in contrast to the vast majorities of studies in the non-relativistic framework, where the next-to-next-to-leading order two-body and three-body chiral forces are needed. This study sets the foundation for studying nuclear saturation with the covariant chiral force in the RBHF framework, which allows for a systematic understanding of one of the key features of nuclear physics more microscopically.

   ↳ nucl-thhep-phnucl-exPLB(2024)·18 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.