Thu·Oct 14, 2021Thursday·October 14, 2021

1. 01*

   General balance functions of identified charged hadron pairs of $(\pi ,\mathrm{K},\mathrm{p})$ in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV

   ALICE Collaboration

   First measurements of balance functions (BFs) of all combinations of identified charged hadron $(\pi ,\mathrm{K},\mathrm{p})$ pairs in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV recorded by the ALICE detector are presented. The BF measurements are carried out as two-dimensional differential correlators versus the relative rapidity ($\Delta y$) and azimuthal angle ($\Delta \phi$) of hadron pairs, and studied as a function of collision centrality. The $\Delta \phi$ dependence of BFs is expected to be sensitive to the light quark diffusivity in the quark$-$gluon plasma. While the BF azimuthal widths of all pairs substantially decrease from peripheral to central collisions, the longitudinal widths exhibit mixed behaviors: BFs of $\pi \pi$ and cross-species pairs narrow significantly in more central collisions, whereas those of $\mathrm{KK}$ and $\mathrm{pp}$ are found to be independent of collision centrality. This dichotomy is qualitatively consistent with the presence of strong radial flow effects and the existence of two stages of quark production in relativistic heavy-ion collisions. Finally, the first measurements of the collision centrality evolution of BF integrals are presented, with the observation that charge balancing fractions are nearly independent of collision centrality in Pb$-$Pb collisions. Overall, the results presented provide new and challenging constraints for theoretical models of hadron production and transport in relativistic heavy-ion collisions.

   nucl-exhep-exPLB(2022)·31 citations
2. 02*

   Temperature and Density Conditions for Alpha Clustering in Excited Self-Conjugate Nuclei

   Bernard Borderie · Adriana Raduta · Enrico De Filippo · Elena Geraci · Nicolas Le Neindre · Giuseppe Cardella · Gaetano Lanzalone · Ivano Lombardo · Olivier Lopez · Concettina Maiolino · Angelo Pagano · Massimo Papa and 3 other authors

   Starting from experimental studies on alpha-clustering in excited self-conjugate nuclei (from ${}^{16}$O to ${}^{28}$Si), temperature and density conditions for such a clustering are determined. Measured temperatures have been found in the range of 5.5 - 6.0 MeV whereas density values of 0.3 - 0.4 times the saturation density are deduced, i.e., 0.046 to 0.062 $f{m}^{-3}$. Such a density domain is also predicted by constrained self-consistent mean field calculations. These results constitute a benchmark for alpha clustering from self-conjugate nuclei in relation to descriptions of stellar evolution and supernovae.

   nucl-exnucl-thSymmetry(2021)·0 citations
3. 03*

   Precise Beam Energy Determination for Hall A after the CEBAF 12 GeV Upgrade

   S. N. Santiesteban🇺🇸 · L. Tracy🇺🇸 · D. Flay🇺🇸 · D. W. Higinbotham🇺🇸 · D. Marchand🇫🇷 · P. Vernin🇫🇷 · A Saha🇺🇸

   Precise and accurate measurements of the beam energy delivered to the experimental halls at the Thomas Jefferson Accelerator Facility (Jefferson Lab) is required by many experiments for proper data analysis and physics event reconstruction. During the 6 GeV era of Jefferson Lab, the energy delivered to experimental Hall A was determined to 2E-4 dE/E with multiple measurements; but after the machine was upgraded to 12 GeV, the accelerator's beam energy calculations needed to be re-calibrated. In order to link the 6 GeV era calibrations to the 12 GeV era, the Hall A ARC energy measurement system was left unmodified. After the upgrade, this system was used to determine the absolute beam energy being delivered into Hall A and find the new calibrations for the main machine. To ensure the validity of these results, they have been cross checked using elastic scattering data as well as spin precession data.

   ↳ physics.acc-phnucl-exphysics.ins-det4 citations
4. 04*

   Fixed particle number constraint in a simple model of a thermal expanding system and $pp$ collisions at the LHC

   M.D. Adzhymambetov🇺🇦 · S.V. Akkelin🇺🇦 · Yu.M. Sinyukov🇺🇦

   Two-boson momentum correlations at fixed particle number constraint are studied in a simple analytically solvable model of a thermal expanding system. We show that the increase of expansion rate, as well as increase of particle multiplicity, enhances the ground-state contribution to particle momentum spectra and leads to suppression of the Bose-Einstein momentum correlations. The relations of these findings to the multiplicity-dependent measurements of the Bose-Einstein momentum correlations in high-multiplicity $p+p$ collision events at the LHC are discussed.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2022)·1 citation

* 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.