Mon·Mar 9, 2020Monday·March 9, 2020

1. 01*

   (Anti-)Deuteron production in pp collisions at $\sqrt{s}=13$ TeV

   ALICE Collaboration

   The study of (anti-)deuteron production in pp collisions has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high energy hadronic collisions. In this paper the production of (anti-)deuterons is studied as a function of the charged particle multiplicity in inelastic pp collisions at $\sqrt{s}=13$ TeV using the ALICE experiment. Thanks to the large number of accumulated minimum bias events, it has been possible to measure (anti-)deuteron production in pp collisions up to the same charged particle multiplicity ($\mathrm{d}{\mathrm{N}}_{\mathrm{ch}}/\mathrm{d}\eta \sim 26$) as measured in p-Pb collisions at similar centre-of-mass energies. Within the uncertainties, the deuteron yield in pp collisions resembles the one in p-Pb interactions, suggesting a common formation mechanism behind the production of light nuclei in hadronic interactions. In this context the measurements are compared with the expectations of coalescence and Statistical Hadronisation Models (SHM).

   nucl-exhep-exEPJC(2020)·89 citations
2. 02*

   Lepton Pair Production Through Two Photon Process in Heavy Ion Collisions

   Spencer Klein🇺🇸 · Al Mueller🇺🇸 · Bo-Wen Xiao🇨🇳 · Feng Yuan🇺🇸

   This paper investigates the electromagnetic production of lepton pairs with low transverse momentum in relativistic heavy ion collisions. We estimate the initial photons' transverse momentum contributions by employing models where the average transverse momentum squared of the incoming photon can be calculated in the equivalent photon approximation. We further derive an all order QED resummation for the soft photon radiation, which gives an excellent description of the ATLAS data in ultra-peripheral collisions at the LHC. For peripheral and central collisions, additional $p_T$-broadening effects from multiple interaction with the medium and the magnetic field contributions from the quark-gluon plasma are also discussed.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2020)·90 citations
3. 03*

   Effects of finite nucleon size, vacuum polarization, and electromagnetic spin-orbit interaction on nuclear binding energies and radii in spherical nuclei

   Tomoya Naito🇯🇵 · Xavier Roca-Maza🇮🇹 · Gianluca Colò🇮🇹 · Haozhao Liang🇯🇵

   The electromagnetic effects of the finite size of the nucleon are implemented self-consistently on top of the Skyrme Hartree-Fock calculation, where the electric form factors of both protons and neutrons are considered. Furthermore, the vacuum polarization and the electromagnetic spin-orbit interaction are taken into account. The self-consistent finite-size effects give a different Coulomb potential from the conventional one and affect the neutrons as well. The contribution of the finite-size effects to the total energy reaches $7\mathrm{MeV}$ in ${}^{208}\mathrm{Pb}$. The vacuum polarization and the electromagnetic spin-orbit interaction are also non-negligible, especially in the heavy nuclei. These effects provide a comparable contribution of the total energy to that of the isospin symmetry-breaking terms of the nuclear interaction. The mirror nuclei mass difference in ${}^{48}\mathrm{Ca}$--${}^{48}\mathrm{Ni}$ is also studied, and its value is improved by approximately one order of magnitude.

   ↳ nucl-thnucl-exPRC(2020)·13 citations
4. 04*

   Commissioning of the CALIFA Barrel Calorimeter of the R${}^3$B Experiment at FAIR

   P Cabanelas · H Alvarez-Pol · J M Boillos · E Casarejos · J Cederkall · D Cortina · M Feijoo · D Galaviz · E Galiana R Gernhäuser · P Golubev · D González · A-L Hartig and 14 other authors

   CALIFA is the high efficiency and energy resolution calorimeter for the R${}^3$B experiment at FAIR, intended for detecting high energy charged particles and $\gamma$-rays in inverse kinematics direct reactions. It surrounds the reaction target in a segmented configuration of Barrel and Forward End-Cap pieces. The CALIFA Barrel consists of 1952 detection units made of CsI(Tl) long-shaped scintillator crystals, and it is being commissioned during the Phase0 experiments at FAIR. The first setup for the CALIFA Barrel commissioning is presented here. Results of detector performance with $\gamma$-rays are obtained, and show that the system fulfills the design requirements.

   ↳ physics.ins-detnucl-exJ.Phys.Conf.Ser.(2020)·0 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.