Thu·Nov 16, 2017Thursday·November 16, 2017

1. 01*

   ${\Sigma }^0$ production in proton nucleus collisions near threshold

   J. Adamczewski-Musch · G. Agakishiev · O. Arnold · E.T. Atomssa · C. Behnke · J.C. Berger-Chen · J. Biernat · A. Blanco · C. Blume · M. Böhmer · P. Bordalo S. Chernenko · C. Deveaux and 91 other authors

   The production of ${\Sigma }^0$ baryons in the nuclear reaction p (3.5 GeV) + Nb (corresponding to $\sqrt{s_{NN}}=3.18$ GeV) is studied with the detector set-up HADES at GSI, Darmstadt. ${\Sigma }^0$s were identified via the decay ${\Sigma }^0\to \Lambda \gamma$ with subsequent decays $\Lambda \to p{\pi }^{-}$ in coincidence with a $e^{+}{e}^{-}$ pair from either external ($\gamma \to e^{+}{e}^{-}$) or internal (Dalitz decay ${\gamma }^{\ast }\to e^{+}{e}^{-}$) gamma conversions. The differential ${\Sigma }^0$ cross section integrated over the detector acceptance, i.e. the rapidity interval $0.5<y<1.1$, has been extracted as $\Delta {\sigma }_{{\Sigma }^0}=2.3\pm (0.2{)}^{stat}\pm {\left({}_{-0.6}^{+0.6}\right)}^{sys}\pm (0.2{)}^{norm}$ mb, yielding the inclusive production cross section in full phase space ${\sigma }_{{\Sigma }^0}^{total}=5.8\pm (0.5{)}^{stat}\pm {\left({}_{-1.4}^{+1.4}\right)}^{sys}\pm (0.6{)}^{norm}\pm (1.7{)}^{extrapol}$ mb by averaging over different extrapolation methods. The ${\Lambda }_{all}$/${\Sigma }^0$ ratio within the HADES acceptance is equal to 2.3 $\pm$ $(0.2{)}^{stat}$ $\pm$ ${(}_{-0.6}^{+0.6}{)}^{sys}$. The obtained rapidity and momentum distributions are compared to transport model calculations. The ${\Sigma }^0$ yield agrees with the statistical model of particle production in nuclear reactions.

   nucl-exPLB(2018)·22 citations
2. 02*

   Lévy femtoscopy with PHENIX at RHIC

   Mate Csanad (for the PHENIX Collaboration)🇭🇺

   In this paper we present the measurement of charged pion two-particle femtoscopic correlation functions in 200 GeV Au+Au collisions, in 31 average transverse mass bins, separately for positive and negative pion pairs. Lévy-shaped source distributions yield a statistically acceptable description of the measured correlation functions, with three physical parameters: correlation strength parameter lambda, Lévy index alpha and Lévy scale parameter R. The transverse mass dependence of these Lévy parameters is then investigated and their physical interpretation is also discussed, and the appearance of a new scaling variable is observed.

   nucl-exUniverse(2017)·11 citations
3. 03*

   Non-Gaussian elliptic-flow fluctuations in PbPb collisions at $\sqrt{s_{{}_{\text{NN}}}}=$ 5.02 TeV

   CMS Collaboration

   Event-by-event fluctuations in the elliptic-flow coefficient $v_2$ are studied in PbPb collisions at $\sqrt{s_{{}_{\text{NN}}}}=$ 5.02 TeV using the CMS detector at the CERN LHC. Elliptic-flow probability distributions $p(v_2)$ for charged particles with transverse momentum 0.3 $<p_{\mathrm{T}}<$ 3.0 GeV and pseudorapidity $|\eta |<$ 1.0 are determined for different collision centrality classes. The moments of the $p(v_2)$ distributions are used to calculate the $v_2$ coefficients based on cumulant orders 2, 4, 6, and 8. A rank ordering of the higher-order cumulant results and nonzero standardized skewness values obtained for the $p(v_2)$ distributions indicate non-Gaussian initial-state fluctuation behavior. Bessel-Gaussian and elliptic power fits to the flow distributions are studied to characterize the initial-state spatial anisotropy.

   nucl-exhep-exPLB(2019)·85 citations
4. 04*

   Femtoscopy via Levy sources with PHENIX at RHIC

   Mate Csanad (for the PHENIX Collaboration)🇭🇺

   Charged pion two-particle correlation functions were measured in 0-30% centrality 200 GeV Au+Au collisions with the PHENIX experiment at RHIC. The measured correlation functions can be statistically well described based on the assumption of Levy-shaped source distributions. In this proceedings paper we present the Levy parameters of the measured correlation functions: correlation strength parameter lambda, Levy index alpha and Levy scale parameter R as a function of pair transverse mass mT, in 31 bins from 228 to 871 MeV, separately for positive and negative pion pairs. We discuss the physical interpretation of the mT dependence of the parameters.

   nucl-exNuovo Cim.C(2018)·0 citations
5. 05*

   Half-lives of neutron-rich ${}^{128-130}$Cd

   Dunlop · R. · Bildstein · V. · Dillmann · I. · Jungclaus · A. · Svensson · C. E. · Andreoiu · C. and 74 other authors

   The $\beta$-decay half-lives of ${}^{128\text{–}130}$Cd have been measured with the newly commissioned GRIFFIN $\gamma$-ray spectrometer at the TRIUMF-ISAC facility. The time structures of the most intense $\gamma$-rays emitted following the $\beta$-decay were used to determine the half-lives of ${}^{128}$Cd and ${}^{130}$Cd to be $T_{1/2}=246.2(21)$ ms and $T_{1/2}=126(4)$ ms, respectively. The half-lives of the 3/2${}^{+}$ and 11/2${}^{-}$ states of ${}^{129}$Cd were measured to be $T_{1/2}(3/2^{+})=157(8)$ ms and $T_{1/2}(11/2^{-})=147(3)$ ms. The half-lives of the Cd isotopes around the $N=82$ shell closure are an important ingredient in astrophysical simulations to derive the magnitude of the second $r$-process abundance peak in the $A\sim 130$ region. Our new results are compared with recent literature values and theoretical calculations.

   nucl-exPRC(2016)·23 citations
6. 06*

   Anisotropy of thermal dileptons

   V.V. Goloviznin🇷🇺 · A.M. Snigirev🇷🇺 · G.M. Zinovjev🇺🇦

   The meaningful specific anisotropy in the angle distribution of leptons with respect to the three-momentum of pair is predicted as a feasibility signature of synchrotron-like mechanism resulting from the quarks interacting with a collective confining color field in the heavy ion collisions. The lepton pair production rate and the spectrum of pair invariant mass are presented for this new dilepton source that is apparently not taken into consideration in the available phenomenological estimates.

   ↳ hep-phnucl-exnucl-th1 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.