Thu·Nov 7, 2019Thursday·November 7, 2019

1. 01*

   Balance functions of charged hadron pairs $(\pi ,K,p)\otimes (\pi ,K,p)$ in Pb--Pb collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=$2.76 TeV

   Jinjin Pan🇺🇸

   We present the first balance function (BF) measurement of charged hadron pairs $(\pi ,K,p)\otimes (\pi ,K,p)$ in Pb--Pb collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=$2.76 TeV. The BF measurements are carried out as two-dimensional (2D) differential correlators vs. the relative rapidity ($\Delta y$) and azimuthal angle ($\Delta \phi$) of hadron pairs, and studied as a function of collision centrality. While the BF azimuthal widths of all pairs substantially decrease from peripheral to central collisions, the longitudinal widths exhibit mixed behaviors: BF of $\pi \pi$ and cross-species pairs narrow in more central collisions whereas those of $KK$ and $pp$ are found invariant with collision centrality. This dichotomy is qualitatively consistent with the presence of strong radial flow effects and the existence of two waves of quark production in relativistic heavy ion collisions. We additionally present first measurements of the BF integrals and find that hadron pairing probabilities are very different from single hadron ratios and feature minimal collision centrality dependence. Overall, the results presented provide new and challenging constraints for theoretical models of hadron production and transport in relativistic heavy ion collisions.

   nucl-ex1 citation
2. 02*

   Probing QCD matter via $K^{\ast 0}(892)$ and $\varphi (1020)$ resonance production at RHIC

   Md Nasim (for the STAR Collaboration)🇮🇳

   We present the measurements of invariant yields of $K^{\ast 0}$ and $\varphi$ resonances at midrapidity in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7 - 200 GeV using the STAR detector. The transverse momentum ($p_T$) spectra and $p_T$-integrated yields of $K^{\ast 0}$ and $\varphi$ have been studied. The ratios between resonance ($K^{\ast 0}$ and $\varphi$) to non-resonance particles ($K$) are presented as a function of centrality. It is found that $K^{\ast 0}/K^{-}$ ratios are suppressed in the most central collisions as compared to peripheral ones for all studied collision energies. On the other hand, $\varphi /K^{-}$ ratios are weakly depend on centrality. These results can be understood by considering the effect of more hadronic rescattering for $K^{\ast 0}$ (lifetime $\sim$ 4 fm/c) as compared to $\varphi$ (lifetime $\sim$ 42 fm/c). We have also presented the measurement of the first-order azimuthal anisotropy (known as directed flow, $v_1$) of $\varphi$ meson as a function of rapidity ($y$) at midrapidity in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7 - 200 GeV. The slope of $\varphi$-meson $v_1$ ($d{v}_1/dy$) has been compared to the $d{v}_1/dy$ of other identified particles. We have found that all particles that consist of produced quarks show similar behaviour for $\sqrt{s_{NN}}$ $>$ 14.5 GeV.

   nucl-exSpringer Proc.Phys.(2020)·2 citations
3. 03*

   First search for Lorentz violation in double beta decay with scintillating calorimeters

   O. Azzolini🇮🇹 · J.W. Beeman🇺🇸 · F. Bellini🇮🇹 · M. Beretta🇮🇹 · M. Biassoni🇮🇹 · C. Brofferio🇮🇹 · C. Bucci🇮🇹 · S. Capelli🇮🇹 · L. Cardani🇮🇹 · P. Carniti🇮🇹 · N. Casali🇮🇹 · D. Chiesa🇮🇹 and 33 other authors

   We present the search for Lorentz violation in the double beta decay of ^{82}Se~with CUPID-0, using an exposure of 9.95 kg x y. We found no evidence for the searched signal and set a limit on the isotropic components of the Lorentz violating coefficient of ${\mathring{a}}_{\text{of}}^{(3)}<4.1\cdot 10^{-6}$ GeV (90\% Credible Interval). This results is obtained with a Bayesian analysis of the experimental data and fully includes the systematic uncertainties of the model. This is the first limit on ${\mathring{a}}_{\text{of}}^{(3)}$ obtained with a scintillating bolometer, showing the potentiality of this technique.

   nucl-exphysics.ins-detPRD(2019)·38 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.