Thu·Jan 24, 2019Thursday·January 24, 2019

1. 01*

   Measurement of ${\mathrm{D}}^0$, ${\mathrm{D}}^{+}$, ${\mathrm{D}}^{\ast +}$ and ${{\mathrm{D}}^{+}}_s$ production in pp collisions at $\sqrt{\text{s}}=5.02\mathbf{TeV}$ with ALICE

   Alice Collaboration

   The measurements of the production of prompt ${\mathrm{D}}^0$, ${\mathrm{D}}^{+}$, ${\mathrm{D}}^{\ast +}$, and ${{\mathrm{D}}^{+}}_s$ mesons in proton--proton (pp) collisions at $\sqrt{s}=5.02$ TeV with the ALICE detector at the Large Hadron Collider (LHC) are reported. D mesons were reconstructed at mid-rapidity ($|y|<0.5$) via their hadronic decay channels ${\mathrm{D}}^0\to {\mathrm{K}}^{-}{\pi }^{+}$, ${\mathrm{D}}^{+}\to {\mathrm{K}}^{-}{\pi }^{+}{\pi }^{+}$, ${\mathrm{D}}^{\ast +}\to {\mathrm{D}}^0{\pi }^{+}\to {\mathrm{K}}^{-}{\pi }^{+}{\pi }^{+}$, ${\mathrm{D}}_{\mathrm{s}}^{+}\to \varphi {\pi }^{+}\to {\mathrm{K}}^{+}{\mathrm{K}}^{-}{\pi }^{+}$, and their charge conjugates. The production cross sections were measured in the transverse momentum interval $0<p_{\mathrm{T}}<36\mathrm{GeV}/c$ for ${\mathrm{D}}^0$, $1<p_{\mathrm{T}}<36\mathrm{GeV}/c$ for ${\mathrm{D}}^{+}$ and ${\mathrm{D}}^{\ast +}$, and in $2<p_{\mathrm{T}}<24\mathrm{GeV}/c$ for ${{\mathrm{D}}^{+}}_s$ mesons. Thanks to the higher integrated luminosity, an analysis in finer $p_{\mathrm{T}}$ bins with respect to the previous measurements at $\sqrt{s}=7$ TeV was performed, allowing for a more detailed description of the cross-section $p_{\mathrm{T}}$ shape. The measured $p_{\mathrm{T}}$-differential production cross sections are compared to the results at $\sqrt{s}=7$ TeV and to four different perturbative QCD calculations. Its rapidity dependence is also tested combining the ALICE and LHCb measurements in pp collisions at $\sqrt{s}=5.02$ TeV. This measurement will allow for a more accurate determination of the nuclear modification factor in p-Pb and Pb-Pb collisions performed at the same nucleon-nucleon centre-of-mass energy.

   nucl-exhep-exEPJC(2019)·139 citations
2. 02*

   Charged-particle angular correlations in XeXe collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=$ 5.44 TeV

   CMS Collaboration

   Azimuthal correlations of charged particles in xenon-xenon collisions at a center-of-mass energy per nucleon pair of $\sqrt{s_{{}_{\mathrm{NN}}}}=$ 5.44 TeV are studied. The data were collected by the CMS experiment at the LHC with a total integrated luminosity of 3.42 $\mu$b${}^{-1}$. The collective motion of the system formed in the collision is parameterized by a Fourier expansion of the azimuthal particle density distribution. The azimuthal anisotropy coefficients $v_2$, $v_3$, and $v_4$ are obtained by the scalar-product, two-particle correlation, and multiparticle correlation methods. Within a hydrodynamic picture, these methods have different sensitivities to non-collective and fluctuation effects. The dependence of the Fourier coefficients on the size of the colliding system is explored by comparing the xenon-xenon results with equivalent lead-lead data. Model calculations that include initial-state fluctuation effects are also compared to the experimental results. The observed angular correlations provide new constraints on the hydrodynamic description of heavy ion collisions.

   ↳ hep-exnucl-exPRC(2019)·83 citations
3. 03*

   Heavy ion jet physics studies using precision jet substructure and quark-gluon jet classification

   Yang-Ting Chien🇺🇸

   In the first talk I discuss the usefulness of jet grooming for testing jet quenching mechanisms, and I present a calculation of soft-drop jet mass distribution in proton-proton and heavy ion collisions. In the second talk I discuss the comprehensive studies of quark and gluon jet substructure as a way to search for qualitatively new jet modification signatures. I emphasize the importance of precise understanding of jet substructure as well as powerful analysis tools in future heavy ion jet physics studies, with direct applications to hard probes using heavy flavors and hadronically-decaying electroweak bosons.

   ↳ hep-phhep-exnucl-exnucl-thPoS(2019)·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.