Wed·Sep 14, 2022Wednesday·September 14, 2022

1. 01*

   Effect of radial flow on two particle correlations with identified triggers at intermediate $p_T$ in p-Pb collisions at $\sqrt{s_{NN}}=$ 5.02 TeV

   Debojit Sarkar🇮🇳 · Subikash Choudhury🇮🇳 · Subhasis Chattopadhyay🇮🇳

   Results from the two-particle correlation between identified triggers (pions (${\pi }^{\pm }$) , protons (p/$\bar{p}$))) and un-identified charged particles at intermediate transverse momentum ($p_T$) in p-Pb collisions at $\sqrt{s_{NN}}=$ 5.02 TeV have been presented. The events generated from a hybrid Monte-Carlo event generator, EPOS 3.107 that implements a flux-tube initial conditions followed by event by event 3+1D viscous hydrodynamical evolution, have been analysed to calculate two-dimensional correlation functions in $\Delta \eta$-$\Delta \varphi$. The strength of angular correlations at small relative angles (jet-like correlations), quantified in terms of near-side jet-like per-trigger yield has been calculated as a function of the event multiplicity. The yield associated with pion triggers exhibit negligible multiplicity dependence, while the proton-triggered yield shows a gradual suppression from low to high multiplicity events. In small collision systems like p-Pb where jet modification is expected to be less dominant, the observed suppression may be associated with the hydrodynamical evolution of the bulk system that generates an outward radial flow. Analogous measurements in Au-Au collisions at RHIC energy have shown a hint of dilution in proton-triggered correlation at its highest multiplicity suggesting that the soft physics processes in p-Pb and heavy ion collisions may have qualitative similarity.

   nucl-exhep-exhep-phPLB(2016)·10 citations
2. 02*

   $B\rho$-defined Isochronous Mass Spectrometry and Mass Measurements of ${}^{58}$Ni Fragments

   M. Zhang🇨🇳 · X. Zhou · M. Wang · Y. H. Zhang🇨🇳 · Yu. A. Litvinov🇩🇪 · H. S. Xu🇨🇳 · R. J. Chen🇺🇸 · H. Y. Deng🇨🇳 · C. Y. Fu🇨🇳 · W. W. Ge · H. F. Li · T. Liao and 16 other authors

   A novel isochronous mass spectrometry, termed as $B\rho$-defined IMS, is established at the experimental cooler-storage ring CSRe in Lanzhou. Its potential has been studied through high precision mass measurements of ${}^{58}$Ni projectile fragments. Two time-of-flight detectors were installed in one of the straight sections of CSRe, thus enabling simultaneous measurements of the velocity and the revolution time of each stored short-lived ion. This allows for calculating the magnetic rigidity $B\rho$ and the orbit length $C$ of each ion. The accurate $B\rho (C)$ function has been constructed, which is a universal calibration curve used to deduce the masses of the stored nuclides. The sensitivity to single stored ions, quickness, and background-free characteristics of the method are ideally suited to address nuclides with very short lifetimes and tiniest production yields. In the limiting case of just a single particle, the attained mass resolving power allows one us to determine its mass-over-charge ratio $m/q$ with a remarkable precision of merely $\sim 5$ keV. Masses of $T_z=-3/2$ fp-shell nuclides are re-determined with high accuracy, and the validity of the isospin multiplet mass equation is tested up to the heaviest isospin quartet with $A=55$. The new masses are also used to investigate the mirror symmetry of empirical residual proton-neutron interactions.

   nucl-exEPJA(2023)·32 citations
3. 03*

   Decay of the $\Lambda (1405)$ Hyperon to ${\Sigma }^0{\pi }^0$ Measured at GlueX

   Nilanga Wickramaarachchi🇺🇸 · Reinhard A. Schumacher🇺🇸 · Grzegorz Kalicy (for the GlueX Collaboration)🇺🇸

   Among the light baryons, the $J^{\pi }={\frac{1}{2}}^{-}$ $\Lambda (1405)$ hyperon is an important special case as it sits just below the $N\bar{K}$ threshold and decays almost exclusively to $\Sigma \pi$. Some long-standing hypotheses for $\Lambda (1405)$ are that it could be a $N\bar{K}$ bound state or a $\Sigma \pi$ continuum resonance. It may also be considered as a simple quark-model resonance, the $P$-wave companion of the $\Lambda (1520)$. In recent years chiral unitary models have suggested that there are two isospin zero poles present in this mass region, and that the "line shape" of the $\Lambda (1405)$ depends to what extent each of the two poles are stimulated in a given reaction. Below the $N\bar{K}$ threshold, the $\Lambda (1405)$ decays to the three $\Sigma \pi$ charge combinations. The ${\Sigma }^0{\pi }^0$ mode is purely $I=0$ and it is uncontaminated by complications arising from $I=1$ scattering processes contributing to the reaction mechanism in the ${\Sigma }^{+}{\pi }^{-}$ and ${\Sigma }^{-}{\pi }^{+}$ decays. It is also not affected from production and decay of the nearby ${\Sigma }^0(1385)$ hyperon. The GlueX experiment at Jefferson Lab has been used to study the $\Lambda (1405)\to {\Sigma }^0{\pi }^0$ decay mode. We focus on the preliminary results of $d\sigma /d{M}_{{\Sigma }^0{\pi }^0}$ and fits to the line shape of the $\Lambda (1405)$ region in the $-(t-t_{min})$ range 0 - 1.5 GeV${}^2$ from analyzing the reaction $\gamma p\to K^{+}{\Lambda }^{\ast }$ using the data collected during the first phase of the GlueX program.

   nucl-exhep-exhep-phEPJ Web Conf.(2022)·20 citations
4. 04*

   Hadronization effects on transverse momentum dependent jet fragmentation function in small systems

   Xiang-Pan Duan🇨🇳 · Wenbin Zhao🇺🇸 · Guo-Liang Ma🇨🇳

   The transverse momentum $j_{\mathrm{T}}$-dependent jet fragmentation functions have been investigated in proton+proton (p $+$ p) and proton+lead (p $+$ Pb) collisions at $\sqrt{s_{\mathrm{NN}}}=5.02\mathrm{TeV}$ with a multiphase transport model containing both a simple quark coalescence mechanism and a new hybrid hadronization mechanism with coalescence and fragmentation processes. Hadronized by the new hadronization mechanism, the AMPT model achieves a quantitative description of the $j_{\mathrm{T}}$-dependent jet fragmentation functions measured by ALICE. Besides, no obvious jet-medium interaction and cold nuclear matter effects on the $j_{\mathrm{T}}$-dependent jet fragmentation functions in p $+$ Pb collisions were observed. We found the $j_{\mathrm{T}}$-dependent jet fragmentation functions are dominated by the quark coalescence contribution for the new hadronization mechanism, which can be decomposed into narrow and wide parts. The root mean square value of the wide part depends on the jet radius $R$ and jet transverse momentum $p_{\mathrm{T},\mathrm{jet}}$, which is sensitive to different hadronization mechanisms and their components. Therefore, the $j_{\mathrm{T}}$-dependent jet fragmentation functions are proposed as a sensitive probe to study the non-perturbative hadronization effect of jets in small colliding systems.

   ↳ hep-phnucl-exnucl-thEur.Phys.J.Plus(2023)·4 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.