Thu·Apr 30, 2020Thursday·April 30, 2020

1. 01*

   Nuclear Mass Measurements Map the Structure of Atomic Nuclei and Accreting Neutron Stars

   Z. Meisel🇺🇸 · S. George🇩🇪 · S. Ahn🇺🇸 · D. Bazin🇺🇸 · B. A. Brown🇺🇸 · J. Browne🇺🇸 · J. F. Carpino · H. Chung · R. H. Cyburt · A. Estradé🇺🇸 · M. Famiano🇺🇸 · A. Gade🇺🇸 and 19 other authors

   We present mass excesses (ME) of neutron-rich isotopes of Ar through Fe, obtained via TOF-$B\rho$ mass spectrometry at the National Superconducting Cyclotron Laboratory. Our new results have significantly reduced systematic uncertainties relative to a prior analysis, enabling the first determination of ME for ${}^{58,59}\mathrm{Ti}$, ${}^{62}\mathrm{V}$, ${}^{65}\mathrm{Cr}$, ${}^{67,68}\mathrm{Mn}$, and ${}^{69,70}\mathrm{Fe}$. Our results show the $N=34$ subshell weaken at Sc and vanish at Ti, along with the absence of an $N=40$ subshell at Mn. This leads to a cooler accreted neutron star crust, highlighting the connection between the structure of nuclei and neutron stars.

   nucl-exnucl-thPRC(2020)·31 citations
2. 02*

   Mapping the frontiers of the nuclear mass surface

   Zach Meisel

   Nuclear masses play a central role in nuclear astrophysics, significantly impacting the origin of the elements and observables used to constrain ultradense matter. A variety of techniques are available to meet this need, varying in their emphasis on precision and reach from stability. Here I briefly summarize the status of and near-future for the time-of-flight magnetic-rigidity (TOF-$B\rho$) mass measurement technique, emphasizing the complementary and interconnectedness with higher-precision mass measurement methods. This includes of recent examples from TOF-$B\rho$ mass measurements that map the evolution of nuclear structure across the nuclear landscape and significantly impact the results and interpretation of astrophysical model calculations. I also forecast expected expansion in the known nuclear mass surface from future measurement at the Facility for Rare Isotope Beams.

   nucl-exJ.Phys.Conf.Ser.(2020)·8 citations
3. 03*

   Measurement and simulation of gamma-ray background in a low energy accelerator facility

   Sathi Sharma🇮🇳 · M. Saha Sarkar🇮🇳

   The gamma-ray background in the indoor environment has been measured up to 3 MeV to evaluate the feasibility of studying low cross-section (nanobarn to picobarn range) astrophysical reactions at the Facility for Research in Experimental Nuclear Astrophysics (FRENA), Saha Institute of Nuclear Physics, Kolkata. An n-type coaxial HPGe detector with 20% relative efficiency has been placed at different locations in the accelerator and beam halls for the measurement. The measured activity has been compared with that at two laboratories (with standard brick walls) with and without passive and active radiation shielding. As the halls at FRENA are well shielded by concrete, the contribution of the shielding in indoor gamma-ray background has been delineated by simulation using a 4p-geometry model.

   ↳ physics.ins-detnucl-exJINST(2020)·2 citations
4. 04*

   Heavy-ion physics: freedom to do hot, dense, exciting QCD

   Maria Elena Tejeda-Yeomans🇲🇽

   In these two lectures I review the basics of heavy-ion collisions at relativistic energies and the physics we can do with them. I aim to cover the basics on the kinematics and observables in heavy-ion collider experiments, the basics on the phenomenology of the nuclear matter phase diagram, some of the model building and simulations currently used in the heavy-ion physics community and a selected list of amazing phenomenological discoveries and predictions.

   ↳ nucl-thhep-phnucl-exCERN Yellow Rep.School Proc.(2021)·11 citations
5. 05*

   Pomeron-LQCD model of $J/\Psi$ photo-production on the nucleon

   T.-S. H. Lee🇺🇸

   Based on the vector meson dominance assumption, a Hamiltonian model has been developed to investigate $J/\Psi$ photo-production reaction on the nucleon by using the $J/\Psi$-nucleon potential extracted from a lattice QCD calculation of Phys. Rev. D{\bf 82}, 091501 (2010). It is found that the predicted total cross sections are comparable to the recent data of $J/\Psi$ photo-production reaction from Jefferson Laboratory. The model is then extended to include the two-gluon exchange amplitude modeled by Donnachie and Lanshoff within Regge Phenomenology. The resulting Pomeron-LQCD model can then explain the data up to invariant mass $W=$ 300 GeV. Future improvements needed to reduce the uncertainties of the predictions are discussed. The need of an accurate extraction of $J/\Psi$-N potential at short distances from LQCD is illustrated.

   ↳ nucl-thhep-lathep-phnucl-ex5 citations
6. 06*

   Complete NLO QCD study of single- and double-quarkonium hadroproduction in the colour-evaporation model at the Tevatron and the LHC

   Jean-Philippe Lansberg🇫🇷 · Hua-Sheng Shao🇫🇷 · Nodoka Yamanaka🇫🇷 · Yu-Jie Zhang🇨🇳 · Camille Noûs🇫🇷

   We study the Single-Parton-Scattering (SPS) production of double quarkonia (J/psi+J/psi, J/psi+Upsilon, and Upsilon+Upsilon) in pp and pp(bar) collisions at the LHC and the Tevatron as measured by the CMS, ATLAS, LHCb, and D0 experiments in the Colour-Evaporation Model (CEM), based on the quark-hadron-duality, including Next-to-Leading Order (NLO) QCD corrections up to alpha_s^5. To do so, we also perform the first true NLO --up to alpha_s^4-- study of the p_T-differential cross section for single-quarkonium production. This allows us to fix the non-perturbative CEM parameters at NLO accuracy in the region where quarkonium-pair data are measured. Our results show that the CEM at NLO in general significantly undershoots these experimental data and, in view of the other existing SPS studies, confirm the need for Double Parton Scattering (DPS) to account for the data. Our NLO study of single-quarkonium production at mid and large p_T also confirms the difficulty of the approach to account for the measured p_T spectra; this is reminiscent of the impossibility to fit single-quarkonium data with the sole 3S18 NRQCD contribution from gluon fragmentation. We stress that the discrepancy occurs in a kinematical region where the new features of the improved CEM are not relevant.

   ↳ hep-phhep-exnucl-exnucl-thPLB(2020)·46 citations
7. 07*

   Critical point fluctuations: Finite size and global charge conservation effects

   Roman V. Poberezhnyuk🇺🇦 · Oleh Savchuk🇺🇦 · Mark I. Gorenstein🇺🇦 · Volodymyr Vovchenko🇩🇪 · Kirill Taradiy🇩🇪 · Viktor V. Begun🇵🇱 · Leonid Satarov🇩🇪 · Jan Steinheimer🇩🇪 · Horst Stoecker🇩🇪

   We investigate simultaneous effects of finite system size and global charge conservation on thermal fluctuations in the vicinity of a critical point. For that we consider a finite interacting system which exchanges particles with a finite reservoir (thermostat), comprising a statistical ensemble that is distinct from the common canonical and grand canonical ensembles. As a particular example the van der Waals model is used. The global charge conservation effects strongly influence the cumulants of particle number distribution when the system size is comparable to that of the reservoir. If the system size is large enough to capture all the physics associated with the interactions, the global charge conservation effects can be accurately described and corrected for analytically, within a recently developed subensemble acceptance method. The finite size effects start to play a significant role when the correlation length grows large due to proximity of the critical point or when the system is small enough to be comparable to an eigenvolume of an individual particle. We discuss our results in the context of fluctuation measurements in heavy-ion collisions.

   ↳ hep-phnucl-exnucl-thPRC(2020)·31 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.