Tue·Nov 22, 2022Tuesday·November 22, 2022

1. 01*

   Characterizing system dynamics with two-particle transverse momentum correlations in pp collisions at $\sqrt{s}=7\text{TeV}$ and p$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02\text{TeV}$

   Victor Gonzalez (for the ALICE Collaboration)🇺🇸

   The two-particle differential transverse momentum correlator $G_2$ recently measured in Pb$-$Pb collisions, emerged as a powerful tool to gain insight into particle production mechanisms and to infer transport properties such as the ratio of shear viscosity to entropy density of the medium created in Pb$-$Pb collisions. In this poster, recent ALICE measurements of this correlator in pp collisions at $\sqrt{s}=7$ and p$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV are presented to search, in particular, for viscous effects expected to arise in fluid-like systems produced in these collisions. The strength and shape of the correlator are studied as a function of produced particle multiplicity to look for longitudinal broadening that might reveal the presence of viscous effects in these smaller systems. The measured correlators and their evolution from pp and p$-$Pb to Pb$-$Pb are additionally compared to predictions from Monte Carlo models, and the potential presence of viscous effects is discussed.

   nucl-exhep-exPoS·1 citation
2. 02*

   The legacy of A.H. Wapstra and the future of the Atomic Mass Evaluation

   David Lunney🇫🇷

   This contribution pays homage to Aaldert Wapstra, the founder of the Atomic Mass Evaluation (AME) in its present form. Producing an atomic mass table requires detailed evaluation and combination of the various decay and reaction energies as well as data from inertial mass measurements. Therefore, a brief summary of all mass measurements published since the last ENAM (2004) is given (as of 2008). The status of the AME is then discussed and as well as attempts for its continuation. (Since this paper was the written, coordination of the Atomic Mass Evaluation was taken over by the Chinese Academy of Sciences, Institute of Modern Physics, in Lanzhou.)

   nucl-ex0 citations
3. 03*

   Prompt and non-prompt charm baryons with ALICE

   Jianhui Zhu🇨🇳

   Recent measurements of prompt charm-baryon production at midrapidity in pp and p--Pb collisions show baryon-to-meson yield ratios significantly higher than those in ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ collisions, suggesting that the charm fragmentation is not universal across different collision systems. Thus, more precise and broader measurements of prompt charm-baryon production are crucial to study the charm quark hadronization in a partonic-rich environment like the one produced in pp collisions at the LHC energies. Prompt charm baryon-to-meson yield ratios in proton--nucleus collisions provide important information about possible additional modification of hadronization mechanisms, on cold nuclear matter effects, and on the possible presence of collective effects that could modify the production of heavy-flavor hadrons. The non-prompt charm-hadron production can provide information about the beauty sector and can be used to study flavor dependence of heavy-quark hadronization. In this contribution, the most recent results on prompt and non-prompt charm-hadron yield ratios in pp and p--Pb collisions and on charm fragmentation fractions and charm production cross section at midrapidity per unit of rapidity measured by ALICE are discussed.

   nucl-exhep-exPoS(2022)·1 citation
4. 04*

   Measurement of substructure-dependent jet suppression in Pb+Pb collisions at 5.02 TeV with the ATLAS detector

   ATLAS Collaboration

   The ATLAS detector at the Large Hadron Collider has been used to measure jet substructure modification and suppression in Pb+Pb collisions at a nucleon-nucleon center-of-mass energy $\sqrt{s_{{}_{\mathrm{NN}}}}=5.02\mathrm{TeV}$ in comparison with $pp$ collisions at $\sqrt{s}=5.02\mathrm{TeV}$. The Pb+Pb data, collected in 2018, have an integrated luminosity of $1.72\mathrm{n}{\mathrm{b}}^{-1}$, while the $pp$ data, collected in 2017, have an integrated luminosity of $260{\mathrm{pb}}^{-1}$. Jets used in this analysis are clustered using the anti-$k_t$ algorithm with a radius parameter $R=0.4$. The jet constituents, defined by both tracking and calorimeter information, are used to determine the angular scale $r_{\mathrm{g}}$ of the first hard splitting inside the jet by reclustering them using the Cambridge-Aachen algorithm and employing the soft-drop grooming technique. The nuclear modification factor, $R_{\mathrm{AA}}$, used to characterize jet suppression in Pb+Pb collisions, is presented differentially in $r_{\mathrm{g}}$, jet transverse momentum, and in intervals of collision centrality. The $R_{\mathrm{AA}}$ value is observed to depend significantly on jet $r_{\mathrm{g}}$. Jets produced with the largest measured $r_{\mathrm{g}}$ are found to be twice as suppressed as those with the smallest $r_{\mathrm{g}}$ in central Pb+Pb collisions. The $R_{\mathrm{AA}}$ values do not exhibit a strong variation with jet $p_{\mathrm{T}}$ in any of the $r_{\mathrm{g}}$ intervals. The $r_{\mathrm{g}}$ and $p_{\mathrm{T}}$ dependence of jet $R_{\mathrm{AA}}$ is qualitatively consistent with a picture of jet quenching arising from coherence and provides the most direct evidence in support of this approach.

   nucl-exhep-exPRC(2023)·75 citations
5. 05*

   Beam energy dependence of the linear and mode-coupled flow harmonics in Au+Au collisions

   STAR Collaboration: B. E. Aboona🇺🇸 · J. Adam🇨🇿 · J. R. Adams🇺🇸 · G. Agakishiev🇷🇺 · I. Aggarwal🇮🇳 · M. M. Aggarwal🇮🇳 · Z. Ahammed🇮🇳 · A. Aitbaev🇷🇺 · I. Alekseev🇷🇺 · D. M. Anderson🇺🇸 · A. Aparin🇷🇺 · J. Atchison🇺🇸 and 345 other authors

   The linear and mode-coupled contributions to higher-order anisotropic flow are presented for Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 27, 39, 54.4, and 200 GeV and compared to similar measurements for Pb+Pb collisions at the Large Hadron Collider (LHC). The coefficients and the flow harmonics' correlations, which characterize the linear and mode-coupled response to the lower-order anisotropies, indicate a beam energy dependence consistent with an influence from the specific shear viscosity ($\eta /s$). In contrast, the dimensionless coefficients, mode-coupled response coefficients, and normalized symmetric cumulants are approximately beam-energy independent, consistent with a significant role from initial-state effects. These measurements could provide unique supplemental constraints to (i) distinguish between different initial-state models and (ii) delineate the temperature ($T$) and baryon chemical potential (${\mu }_B$) dependence of the specific shear viscosity $\frac{\eta }{s}(T,{\mu }_B)$.

   nucl-exPLB(2023)·14 citations
6. 06*

   A Review of NEST Models for Liquid Xenon and Exhaustive Comparison to Other Approaches

   M. Szydagis🇺🇸 · J. Balajthy🇺🇸 · G.A. Block🇺🇸 · J.P. Brodsky🇺🇸 · E. Brown🇺🇸 · J.E. Cutter🇺🇸 · S.J. Farrell🇺🇸 · J. Huang🇨🇭 · A.C. Kamaha🇺🇸 · E.S. Kozlova🇷🇺 · C.S. Liebenthal🇺🇸 · D.N. McKinsey🇺🇸 and 14 other authors

   This paper will discuss the microphysical simulation of interactions in liquid xenon, the active detector medium in many leading rare-event searches for new physics, and describe experimental observables useful for understanding detector performance. The scintillation and ionization yield distributions for signal and background will be presented using the Noble Element Simulation Technique (NEST), which is a toolkit based on experimental data and simple, empirical formulae, which mimic previous microphysics modeling, but are guided by data. The NEST models for light and charge production as a function of the particle type, energy, and electric field will be reviewed, as well as models for energy resolution and final pulse areas. NEST will be compared to other models or sets of models, and vetted against real data, with several specific examples pulled from XENON, ZEPLIN, LUX, LZ, PandaX, and table-top experiments used for calibrations.

   ↳ hep-exastro-ph.IMnucl-exphysics.ins-detFront.Detect.Sci.Tech.(2024)·62 citations
7. 07*

   Effects of Non-Vanishing Net Charge in Balance Functions

   Claude Pruneau🇺🇸 · Victor Gonzalez🇺🇸 · Brian Hanley🇺🇸 · Ana Marin🇩🇪 · Sumit Basu🇸🇪

   We investigate the impact of non-vanishing net-charge in collision systems on measurements of balance functions and their integrals. We show that the nominal balance function definition yields integrals that deviate from unity because of the non-vanishing net-charge. However, the integral of unified balance functions is shown to appropriately converge to unity when measured in a sufficiently wide experimental acceptance. We furthermore explore the rate of convergence of unified balance functions integrals and study distortions imparted on the shape of balance functions when measurements are carried out in limited transverse momentum ($p_{\mathrm{T}}$) and rapidity ($y$) acceptances, such as those featured by experiments at the Large Hadron Collider or the Relativistic Heavy Ion Collider. We show that the shape and integral of unified balance functions may be strongly biased by reductions in the rapidity and transverse momentum acceptances of existing experiments.

   ↳ hep-phnucl-exPRC(2023)·7 citations
8. 08*

   Soft dipole resonance in neutron-rich ${}^8$He

   Takayuki Myo🇯🇵 · Myagmarjav Odsuren · Kiyoshi Kato

   In neutron-rich ${}^8$He, we study the soft dipole resonance, which is regarded as a dipole oscillation of four valence neutrons against the ${}^4$He core, and its effect on the low-energy electric dipole strength with a ${}^4$He+$n$+$n$+$n$+$n$ five-body cluster model. This work is an extended study of an earlier letter [T. Myo and K. Katō, Phys. Rev. C106, L021302 (2022)]. The five-body unbound $1^{-}$ states of ${}^8$He are obtained with the complex energy eigenvalues by using the complex scaling method and the dipole strength is calculated in terms of the complex-scaled Green's function. Two kinds of the dominant excitation modes are confirmed in the dipole strength below 20 MeV of the excitation energy. The strengths below 10 MeV are exhausted by the ${}^7$He+$n$ channel, which sequentially decays to ${}^6$He+$n$+$n$. Above 10 MeV, the strengths arise from the soft dipole mode of four neutrons ($4n$) oscillating against the ${}^4$He core. We further explore the possibility of the soft dipole resonance for this state by carefully searching for the resonance pole and finally predict the corresponding resonance with the excitation energy of 14 MeV and the decay width of 21 MeV. The soft dipole resonance exhausts about half of the dipole strength in the relative motion between the ${}^4$He core and $4n$.

   ↳ nucl-thnucl-exPTEP(2022)·8 citations
9. 09*

   The Future of US Particle Physics -- The Snowmass 2021 Energy Frontier Report

   Meenakshi Narain · Laura Reina · Alessandro Tricoli · Michael Begel · Alberto Belloni · Tulika Bose · Antonio Boveia · Sally Dawson · Caterina Doglioni · Ayres Freitas · James Hirschauer · Stefan Hoeche and 23 other authors

   This report, as part of the 2021 Snowmass Process, summarizes the current status of collider physics at the Energy Frontier, the broad and exciting future prospects identified for the Energy Frontier, the challenges and needs of future experiments, and indicates high priority research areas.

   ↳ hep-exhep-lathep-phhep-th+196 citations
10. 10*

    Commissioning and first performances of the ALICE MID RPCs

    Livia Terlizzi (for the ALICE Collaboration)🇮🇹

    ALICE (A Large Ion Collider Experiment) at the CERN Large Hadron Collider (LHC) is designed to study p-p and Pb-Pb collisions at ultra-relativistic energies. ALICE is equipped with a Muon Spectrometer (MS) to study the heavy charmonia in p-p and heavy ion collisions via their muonic decay. At first, in the LHC Run 1 and 2 the selection of interesting events for muon physics in the MS was performed with a dedicated Muon Trigger system based on Resistive Plate Chambers (RPCs) operated in maxi-avalanche mode. During the Long Shutdown 2 (LS2) of LHC ALICE underwent a major upgrade of its apparatus: since Run 3 (started in July 2022), in order to fully profit from the increased luminosity of Pb-Pb collisions (from 20 kHz in Run 2 to 50 kHz in Run 3), the ALICE experiment is running in continuous readout (triggerless) mode and the Muon Trigger became the Muon IDentifier (MID). In order to reduce the RPC ageing and to increase the rate capability, it was decided to use a new front-end electronics FEERIC with a pre-amplification stage to minimize the charge released per hit inside the gas gap. A description of the MID upgrades, together with the results and performances of the RPCs from the commissioning, is presented in this talk.

    ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2023)·2 citations
11. 11*

    Toy model to understand oscillatory behavior in timelike nucleon form factors

    Ri-Qing Qian🇨🇳 · Zhan-Wei Liu🇨🇳 · Xu Cao🇨🇳 · Xiang Liu🇨🇳

    To understand the oscillatory behavior exhibited in the timelike electromagnetic form factors of nucleons, we propose a toy model based on the Jost function of the $N\bar{N}$ pair into the timelike form factors with the help of the distorted-wave Born approximation. By constructing a simple square-well potential reflecting the final-state interaction of $N\bar{N}$, we naturally represent the damped oscillatory phenomenon in the timelike electromagnetic form factors of nucleons. Especially, our study reveals that the ``period" of the oscillation is approximately determined by the Yukawa interaction range $1/m_{\pi }$. Other possible potentials are also discussed. The threshold enhancements of the cross sections for $e^{+}{e}^{-}\to n\bar{n}$, $\Lambda \bar{\Lambda }$, and ${\Lambda }_c{\bar{\Lambda }}_c$ can also be understand within this scenario.

    ↳ nucl-thhep-exhep-phnucl-exPRD(2023)·17 citations
12. 12*

    Probing the Non-exponential Decay Regime in Open Quantum Systems

    S. M. Wang🇺🇸 · W. Nazarewicz🇺🇸 · A. Volya🇺🇸 · Y. G. Ma🇨🇳

    The most important law of radioactivity is that of the exponential decay. In the realm of quantum mechanics, however, this decay law is neither rigorous nor fundamental. The deviations from the exponential decay have been observed experimentally at the early stage of a decay process, but there is little evidence for non-exponential behavior at long times. Yet such long-term non-exponentiality is expected theoretically to probe the non-resonant background components of the initial wave function which preserve the structural interference and the memory of how the state was created. In this paper, we propose new observables that can be used for experimental investigations of the post-exponential decay regime, including the decay of threshold resonances, particle correlations in three-body decays, and interference between near-lying resonances. While the specific examples presented in this work pertain to atomic nuclei, the properties of non-exponential decay are generic, i.e., they apply to other many-body open quantum systems, such as hadrons, atoms, molecules, and nanostructures.

    ↳ nucl-thnucl-exquant-phPRResearch(2023)·24 citations
13. 13*

    QCD Equation of State of Dense Nuclear Matter from a Bayesian Analysis of Heavy-Ion Collision Data

    Manjunath Omana Kuttan🇩🇪 · Jan Steinheimer🇩🇪 · Kai Zhou🇩🇪 · Horst Stoecker🇩🇪

    Bayesian methods are used to constrain the density dependence of the QCD Equation of State (EoS) for dense nuclear matter using the data of mean transverse kinetic energy and elliptic flow of protons from heavy ion collisions (HIC), in the beam energy range $\sqrt{s_{\mathrm{NN}}}=2-10GeV$. The analysis yields tight constraints on the density dependent EoS up to 4 times the nuclear saturation density. The extracted EoS yields good agreement with other observables measured in HIC experiments and constraints from astrophysical observations both of which were not used in the inference. The sensitivity of inference to the choice of observables is also discussed.

    ↳ hep-phhep-exnucl-exnucl-thPRL(2023)·65 citations
14. 14*

    Dead-cone searches in heavy-ion collisions using the jet tree

    Leticia Cunqueiro🇮🇹 · Davide Napoletano🇮🇹 · Alba Soto-Ontoso🇨🇭

    We explore the possibility of using the dead cone of heavy quarks as a region of the Lund plane where medium-induced gluon radiation can be isolated and characterised. The filling of the dead cone by medium-induced gluons is expected to be the result of the interplay between the minimum angle of such radiation due to transverse momentum broadening and the dead-cone angle. Since the measurement of a fully corrected Lund plane in heavy-ion collisions is currently challenging, we propose to use jet grooming techniques to identify a particular splitting in the jet tree that is both perturbative and sensitive to the dead-cone effect. To that end, we propose a new jet substructure groomer, dubbed Late-$k_t$, that selects the most collinear splitting in a QCD jet above a certain transverse momentum cutoff $k_{t,\mathrm{cut}}$. The role of $k_{t,\mathrm{cut}}$ is to guarantee perturbative splittings, while selecting the most collinear splitting enhances the sensitivity to mass effects. As a proof of concept, we study the angular distribution of the splitting tagged by Late-$k_t$ both analytically and with Monte Carlo simulations. First, we derive the logarithmic resummation structure in vacuum and demonstrate its capability to distinguish between inclusive and heavy-flavoured jets. Next, we extend the calculation for in-medium jets and show that medium-induced emissions lead to an enhancement of collinear emissions below the dead cone angle. Numerically, we demonstrate an excellent resilience of Late-$k_t$ against uncorrelated thermal background, thus confirming this observable as a potential candidate to unveil medium dynamics around the dead cone regime.

    ↳ hep-phhep-exnucl-exnucl-thPRD(2023)·27 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.