Wed·Nov 13, 2019Wednesday·November 13, 2019

1. 01*

   Measurement of the azimuthal anisotropy of charged-particle production in Xe+Xe collisions at $\sqrt{s_{\mathrm{NN}}}=5.44$ TeV with the ATLAS detector

   ATLAS Collaboration

   This paper describes the measurements of flow harmonics $v_2$-$v_6$ in 3 $\mu {\mathrm{b}}^{-1}$ of Xe+Xe collisions at $\sqrt{s_{\mathrm{NN}}}=5.44$ TeV performed using the ATLAS detector at the LHC. Measurements of the centrality, multiplicity and $p_{\mathrm{T}}$ dependence of the $v_n$ obtained using two-particle correlations and the scalar product technique are presented. The measurements are also performed using a template-fit procedure, which was developed to remove non-flow correlations in small collision systems. This non-flow removal is shown to have a significant influence on the measured $v_n$ at high $p_{\mathrm{T}}$, especially in peripheral events. Comparisons of the measured $v_n$ with measurements in Pb+Pb collisions and $p$+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV are also presented. The $v_n$ values in Xe+Xe collisions are observed to be larger than those in Pb+Pb collisions for $n=2$, 3 and 4 in the most central events. However, with decreasing centrality or increasing harmonic order $n$, the $v_n$ values in Xe+Xe collisions become smaller than those in Pb+Pb collisions. The $v_n$ in Xe+Xe and Pb+Pb collisions are also compared as a function of the mean number of participating nucleons, $⟨N_{\text{part}}⟩$, and the measured charged-particle multiplicity in the detector. The $v_3$ values in Xe+Xe and Pb+Pb collisions are observed to be similar at the same $⟨N_{\text{part}}⟩$ or multiplicity, but the other harmonics are significantly different. Comparisons of the $v_n$ measurements with theoretical calculations are also made.

   nucl-exhep-exPRC(2020)·85 citations
2. 02*

   Emergence of simple patterns in many-body systems: from macroscopic objects to the atomic nucleus

   R.F. Garcia Ruiz🇨🇭 · A.R. Vernon🇬🇧

   Strongly correlated many-body systems often display the emergence of simple patterns and regular behaviour of their global properties. Phenomena such as clusterization, collective motion and appearance of shell structures are commonly observed across different size, time, and energy scales in our universe. Although at the microscopic level their individual parts are described by complex interactions, the collective behaviour of these systems can exhibit strikingly regular patterns. This contribution provides an overview of the experimental signatures that are commonly used to identify the emergence of shell structures and collective phenomena in distinct physical systems. Examples in macroscopic systems are presented alongside features observed in atomic nuclei. The discussion is focused on the experimental trends observed for exotic nuclei in the vicinity of nuclear closed-shells, and the new challenges that recent experiments have posed in our understanding of emergent phenomena in nuclei.

   nucl-exnlin.AOphysics.atom-phphysics.hist-ph+1EPJA(2020)·28 citations
3. 03*

   Evolution of fluctuations in the initial state of heavy-ion collisions from RHIC to LHC

   Giuliano Giacalone🇫🇷 · François Gelis🇫🇷 · Pablo Guerrero-Rodríguez🇫🇮 · Matthew Luzum🇧🇷 · Cyrille Marquet🇫🇷 · Jean-Yves Ollitrault🇫🇷

   Fluctuations in the initial state of heavy-ion collisions are larger at RHIC energy than at LHC energy. This fact can be inferred from recent measurements of the fluctuations of the particle multiplicities and of elliptic flow performed at the two different energies. We show that an analytical description of the initial energy-density field and its fluctuations motivated by the color glass condensate (CGC) effective theory predicts and quantitatively captures the measured energy evolution of these observables. The crucial feature is that fluctuations in the CGC scale like the inverse of the saturation scale of the nuclei.

   ↳ nucl-thhep-exhep-phnucl-exSpringer Proc.Phys.(2020)·6 citations
4. 04*

   Strangeness production in p--Pb collisions at 8.16 TeV

   Meenakshi Sharma (for the ALICE Collaboration)🇮🇳

   A Large Ion Collider Experiment (ALICE) is one of the four big experiments installed at the CERN Large Hadron Collider (LHC) and it is suited to study pp, p--Pb and Pb--Pb collisions. It aims to study the strongly interacting matter at extreme conditions of temperature and density under which the quarks decouple to form a new state of matter called the Quark Gluon Plasma (QGP). Such a state of matter existed a few microseconds after the Big Bang in which the universe was created. Several experimental observables, sensitive to the evolution of the system after the nuclear collisions, reveal important information about the properties of the QGP. Among such observables is the production rate of strange quarks. It is now confirmed that the strange quarks would be produced with higher probability in a QGP scenario with respect to that expected in a pure hadron gas scenario. Therefore, studies of strangeness production can help to determine the properties of the created system. The studies are now revised at much higher LHC energies and are compared with the lower energy measurements to clarify the full picture. The work which will be presented here is related to the strangeness production in p--Pb collisions with ALICE detector. These collisions in particular, can contribute to the understanding of the differences between small and large interacting systems. The excellent tracking and particle identification capabilities of ALICE can be used to reconstruct the strange hadrons by means of the tracks of their weak decays. The analysis status of strange ($K_s^0$ and $\Lambda$) hadrons in p--Pb at $8.16\text{ TeV}$ at mid-rapidity as a function of $p_{\mathrm{T}}$ and centrality will be presented. The comparison of the experimental results with the EPOS and DPMJet predictions will be also discussed.

   ↳ hep-exnucl-exSpringer Proc.Phys.(2021)·5 citations
5. 05*

   Extraction of the neutron charge radius from a precision calculation of the deuteron structure radius

   A.A. Filin🇩🇪 · V. Baru🇩🇪 · E. Epelbaum🇩🇪 · H. Krebs🇩🇪 · D. Möller🇩🇪 · P. Reinert🇩🇪

   We present a high-accuracy calculation of the deuteron structure radius in chiral effective field theory. Our analysis employs the state-of-the-art semilocal two-nucleon potentials and takes into account two-body contributions to the charge density operators up to fifth order in the chiral expansion. The strength of the fifth-order short-range two-body contribution to the charge density operator is adjusted to the experimental data on the deuteron charge form factor. A detailed error analysis is performed by propagating the statistical uncertainties of the low-energy constants entering the two-nucleon potentials and by estimating errors from the truncation of the chiral expansion as well as from uncertainties in the nucleon form factors. Using the predicted value for the deuteron structure radius together with the very accurate atomic data for the difference of the deuteron and proton charge radii we, for the first time, extract the charge radius of the neutron from light nuclei. The extracted value reads $r_n^2=-0.106\begin{array}{c}+0.007\\ -0.005\end{array}{\text{fm}}^2$ and its magnitude is about $1.7\sigma$ smaller than the current value given by the Particle Data Group. In addition, given the high accuracy of the calculated deuteron charge form factor and its careful and systematic error analysis, our results open the way for an accurate determination of the nucleon form factors from elastic electron-deuteron scattering data measured at the Mainz Microtron and other experimental facilities.

   ↳ nucl-thnucl-exPRL(2020)·78 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.