Thu·Jan 18, 2024Thursday·January 18, 2024

1. 01*

   Flow and correlations measurements in small and large systems

   Lucia Anna Tarasovičová (for the ALICE, CMS and ATLAS Collaboration)🇸🇰

   Measurements of flow coefficients and correlations between different types of particles are used to characterise the properties of the quark-gluon plasma created in heavy-ion collisions. Moreover, these precise measurements became a key observable in understanding the possible origin of the collective-like behaviour in small collision systems. Recent results of flow and correlations measurements of light and heavy hadrons, in pp, p-Pb, and Pb-Pb collisions are presented.

   nucl-exhep-exPoS(2024)·0 citations
2. 02*

   First study of antihyperon-nucleon scattering $\bar{\Lambda }p\to \bar{\Lambda }p$ and measurement of $\Lambda p\to \Lambda p$ cross section

   BESIII Collaboration: M. Ablikim · M. N. Achasov · P. Adlarson · O. Afedulidis · X. C. Ai · R. Aliberti · A. Amoroso · Q. An · Y. Bai · O. Bakina · I. Balossino · Y. Ban and 646 other authors

   Using $(10.087\pm 0.044)\times 10^9$ $J/\psi$ events collected with the BESIII detector at the BEPCII storage ring, the processes $\Lambda p\to \Lambda p$ and $\bar{\Lambda }p\to \bar{\Lambda }p$ are studied, where the $\Lambda /\bar{\Lambda }$ baryons are produced in the process $J/\psi \to \Lambda \bar{\Lambda }$ and the protons are the hydrogen nuclei in the cooling oil of the beam pipe. Clear signals are observed for the two reactions. The cross sections in $-0.9\le \cos {\theta }_{\Lambda /\bar{\mathrm{\Lambda }}}\le 0.9$ are measured to be $\sigma (\Lambda p\to \Lambda p)=(12.2\pm 1.6_{\mathrm{stat}}\pm 1.1_{\mathrm{sys}})$ mb and $\sigma (\bar{\Lambda }p\to \bar{\Lambda }p)=(17.5\pm 2.1_{\mathrm{stat}}\pm 1.6_{\mathrm{sys}})$ mb at the $\Lambda /\bar{\Lambda }$ momentum of $1.074$ GeV/$c$ within a range of $\pm 0.017$ GeV/$c$, where the ${\theta }_{\Lambda /\bar{\Lambda }}$ are the scattering angles of the $\Lambda /\bar{\Lambda }$ in the $\Lambda p/\bar{\Lambda }p$ rest frames. Furthermore, the differential cross sections of the two reactions are also measured, where there is a slight tendency of forward scattering for $\Lambda p\to \Lambda p$, and a strong forward peak for $\bar{\Lambda }p\to \bar{\Lambda }p$. We present an approach to extract the total elastic cross sections by extrapolation. The study of $\bar{\Lambda }p\to \bar{\Lambda }p$ represents the first study of antihyperon-nucleon scattering, and these new measurements will serve as important inputs for the theoretical understanding of the (anti)hyperon-nucleon interaction.

   ↳ hep-exnucl-exPRL(2024)·37 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.