Fri·Jul 18, 2025Friday·July 18, 2025

1. 01*

   ${\overline{\Sigma }}^{\pm }$ production in pp and p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV with ALICE

   ALICE Collaboration

   The transverse momentum spectra and integrated yields of anti-$\Sigma$ hyperons (${\overline{\Sigma }}^{\pm }$) have been measured in pp and p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with the ALICE experiment. Measurements are performed via the newly accessed decay channel ${\overline{\Sigma }}^{\pm }\to \overline{\mathrm{n}}{\pi }^{\pm }$. A new method of antineutron reconstruction with the PHOS electromagnetic spectrometer is developed and applied to this analysis. The $p_{\mathrm{T}}$ spectra of ${\overline{\Sigma }}^{\pm }$ are measured in the range $0.5<p_{\mathrm{T}}<3$ GeV/$c$ and compared to predictions of the PYTHIA 8, DPMJET, PHOJET, EPOS LHC and EPOS4 models. The EPOS LHC and EPOS4 models provide the best descriptions of the measured spectra both in pp and p-Pb collisions, while models which do not account for multiparton interactions provide a considerably worse description at high $p_{\mathrm{T}}$. The total yields of ${\overline{\Sigma }}^{\pm }$ in both pp and p-Pb collisions are compared to predictions of the Thermal-FIST model and dynamical models PYTHIA 8, DPMJET, PHOJET, EPOS LHC and EPOS4. All models reproduce the total yields in both colliding systems within uncertainties. The nuclear modification factors $R_{\mathrm{pPb}}$ for both ${\overline{\Sigma }}^{+}$ and ${\overline{\Sigma }}^{-}$ are evaluated and compared to those of protons, $\Lambda$ and $\Xi$ hyperons, and predictions of EPOS LHC and EPOS4 models. No deviations of $R_{\mathrm{pPb}}$ for ${\overline{\Sigma }}^{\pm }$ from the model predictions or measurements for other hadrons are found within uncertainties.

   nucl-exhep-exEPJC(2026)·3 citations
2. 02*

   Medium-induced modification of azimuthal correlations of electrons from heavy-flavor hadron decays with charged particles in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}=5.02}$ TeV

   ALICE Collaboration

   The azimuthal-correlation distributions between electrons from the decays of heavy-flavor hadrons and associated charged particles in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV are reported for the 0-10% and 30-50% centrality classes. This is the first measurement to provide access to the azimuthal-correlation observables in the heavy-flavor sector in Pb-Pb collisions. The analysis is performed for trigger electrons from heavy-flavor hadron decays with transverse momentum $4<p_{\mathrm{T}}^{\mathrm{e}}<16$ GeV/$c$, considering associated particles within the transverse-momentum range $1<p_{\mathrm{T}}^{\mathrm{assoc}}<7$ GeV/$c$, and a pseudorapidity difference of $|\Delta \eta |<1$ between the trigger electron and associated particles. The per-trigger nuclear modification factor ($I_{\mathrm{AA}}$) is calculated to compare the near- and away-side peak yields to those in pp collisions at $\sqrt{s}=5.02$ TeV. In 0-10% central collisions, the $I_{\mathrm{AA}}$ indicates a hint of enhancement of associated-particle yields with $p_{\mathrm{T}}<3$ GeV/$c$ on the near side, and a suppression of yields with $p_{\mathrm{T}}>4$ GeV/$c$ on the away side. The $I_{\mathrm{AA}}$ for electron triggers from heavy-flavor hadron decays is compared with that for light-flavor and strange-particle triggers to investigate the dependence on different fragmentation processes and parton-medium dynamics, and is found to be the same within uncertainties.

   nucl-exhep-exEPJC(2026)·0 citations
3. 03*

   Precise Measurement of ${}^{216}$Po Half-life with Exact Parent-daughter Pairing in PandaX-4T

   PandaX Collaboration: Chenxiang Li · Zihao Bo · Wei Chen · Xun Chen · Yunhua Chen · Chen Cheng · Xiangyi Cui · Manna Deng · Yingjie Fan · Deqing Fang · Xuanye Fu · Zhixing Gao and 98 other authors

   We report a precise measurement of ${}^{216}\mathrm{Po}$ half-life using the PandaX-4T liquid xenon time projection chamber (TPC). ${}^{220}\mathrm{Rn}$, emanating from a ${}^{228}\mathrm{Th}$ calibration source, is injected to the detector and undergoes successive $\alpha$ decays, first to ${}^{216}\mathrm{Po}$ and then to ${}^{212}\mathrm{Pb}$. PandaX-4T detector measures the 5-dimensional (5D) information of each decay, including time, energy, and 3-dimensional positions. Therefore, we can identify the ${}^{220}\mathrm{Rn}$ and ${}^{216}\mathrm{Po}$ decay events and pair them exactly to extract the lifetime of each ${}^{216}\mathrm{Po}$. With a large data set and high-precision ${}^{220}$Rn-${}^{216}$Po pairing technique, we measure the ${}^{216}\mathrm{Po}$ half-life to be $143.7\pm 0.5$ ms, which is the most precise result to date and agrees with previously published values. The leading precision of this measurement demonstrates the power of 5D calorimeter and the potential of exact parent-daughter pairing in the xenon TPC.

   nucl-exhep-exPRC(2026)·0 citations
4. 04*

   Parton Distribution Functions and their Generalizations

   Cédric Lorcé (Ecole Polytechnique, CPHT)🇫🇷 · A. Metz (Temple U.)🇺🇸 · B. Pasquini (Pavia U. and INFN, Pavia)🇮🇹 · P. Schweitzer (Connecticut U.)🇺🇸

   This article is an introduction to parton distribution functions and their generalizations which describe the quark and gluon structure of hadrons, and can be measured in various high-energy scattering processes. We provide the theoretical background, highlight both historical and recent developments, explain the connections between the different functions, and expose in which processes these functions can be accessed and what we can learn from them about hadron structure.

   ↳ hep-phhep-exhep-latnucl-ex+1Encyclopedia of Particle Physics, Volume …·35 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.