Tue·Jun 28, 2016Tuesday·June 28, 2016

1. 01*

   Photon asymmetry measurements of $\overrightarrow{\gamma }\mathrm{p}\to {\pi }^0\mathrm{p}$ for E${}_{\gamma }$=320$-$650 MeV

   S. Gardner · D. Howdle · M.H. Sikora · Y. Wunderlich · S. Abt · P. Achenbach · F. Afzal · P. Aguar-Bartolome · Z. Ahmed · J.R.M. Annand · H.J. Arends · K. Bantawa and 88 other authors

   High statistics measurements of the photon asymmetry $\mathrm{\Sigma }$ for the $\overrightarrow{\gamma }$p$\to {\pi }^0$p reaction have been made in the center of mass energy range W=1214-1450 MeV. The data were measured with the MAMI A2 real photon beam and Crystal Ball/TAPS detector systems in Mainz, Germany. The results significantly improve the existing world data and are shown to be in good agreement with previous measurements, and with the MAID, SAID, and Bonn-Gatchina predictions. We have also combined the photon asymmetry results with recent cross-section measurements from Mainz to calculate the profile functions, $\check{\mathrm{\Sigma }}$ (= ${\sigma }_0\mathrm{\Sigma }$), and perform a moment analysis. Comparison with calculations from the Bonn-Gatchina model shows that the precision of the data is good enough to further constrain the higher partial waves, and there is an indication of interference between the very small $F$-waves and the $N(1520)3/2^{-}$ and $N(1535)1/2^{-}$ resonances.

   nucl-exEPJA(2016)·19 citations
2. 02*

   Finite-Size Scaling of Non-Gaussian Fluctuations Near the QCD Critical Point

   Roy A. Lacey (1,2)🇺🇸 · Peifeng Liu (1,2)🇺🇸 · Niseem Magdy (1)🇺🇸 · B. Schweid (1,2)🇺🇸 · N. N. Ajitanand (1) ((1) Department of Chemistry, Stony Brook University, (2) Dept. of Physics, Stony Brook University)🇺🇸

   An effective Finite-Size Scaling (FSS) of moment products from recent STAR measurements of the variance $\sigma$, skewness $S$ and kurtosis $\kappa$ of net-proton multiplicity distributions, are reported for a broad range of collision centralities in Au+Au ($\sqrt{s_{NN}}=7.7-200$ GeV) collisions. The products $S\sigma$ and $\kappa {\sigma }^2$, which are directly related to the hgher-order baryon number susceptibility ratios ${\chi }_B^{(3)}/{\chi }_B^{(2)}$ and ${\chi }_B^{(4)}/{\chi }_B^{(2)}$, show scaling patterns consistent with earlier indications for a second order phase transition at a critical end point (CEP) in the plane of temperature vs. baryon chemical potential ($T,{\mu }_B$) of the QCD phase diagram. The resulting scaling functions validate the earlier estimates of $T^{\text{cep}}\sim 165$ MeV and ${\mu }_B^{\text{cep}}\sim 95$ MeV for the location of the CEP, and the critical exponents used to assign its 3D Ising model universality class.

   nucl-exhep-exnucl-th11 citations
3. 03*

   Three Magnetic Rotation Bands in 84^Rb

   Shuifa Shen · Xin Zhao · Guangbing Han · Shuxian Wen · Yupeng Yan🇹🇭 · Xiaoguang Wu · Lihua Zhu🇨🇳 · Chuangye He🇨🇳 · Guangsheng Li

   High-spin states in ${}^{84}$Rb are studied by using the ${}^{70}$Zn(${}^{18}$O, p3n)${}^{84}$Rb reaction at beam energy of 75 MeV. Three high-lying negative-parity bands are established, whose level spacings are very regular, i.e., there don't exist signature splitting. The dipole character of the transitions of these three bands is assigned by the $\gamma$-$\gamma$ directional correlations of oriented states (DCO) intensity ratios and the multipolarity M1 is suggested by the analogy to multiparticle excitations in neighboring nuclei. The strong M1 and weak or no E2 transitions are observed. All these characteristic features show they are magnetic rotation bands.

   nucl-ex0 citations
4. 04*

   J/$\psi$ suppression at forward rapidity in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

   ALICE Collaboration

   The inclusive J/$\psi$ production has been studied in Pn-Pb and pp collisions at the centre-of-mass energy per nucleon pair $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV, using the ALICE detector at the CERN LHC. The J/$\psi$ meson is reconstructed, in the centre-of-mass rapidity interval $2.5<y<4$ and in the transverse-momentum range $p_{\mathrm{T}}<12$ GeV/$c$, via its decay to a muon pair. In this Letter, we present results on the inclusive J/$\psi$ cross section in pp collisions at $\sqrt{s}=5.02$ TeV and on the nuclear modification factor $R_{\mathrm{AA}}$. The latter is presented as a function of the centrality of the collision and, for central collisions, as a function of the transverse momentum $p_{\mathrm{T}}$ of the J/$\psi$. The measured $R_{\mathrm{AA}}$ values indicate a suppression of the J/$\psi$ in nuclear collisions and are then compared to our previous results obtained in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV. The ratio of the $R_{\mathrm{AA}}$ values at the two energies is also computed and compared to calculations of statistical and dynamical models. The numerical value of the ratio for central events (0-10\% centrality) is $1.17\pm 0.04(\mathrm{stat})\pm 0.20(\mathrm{syst})$. In central events, as a function of $p_{\mathrm{T}}$, a slight increase of $R_{\mathrm{AA}}$ with collision energy is visible in the region $2<p_{\mathrm{T}}<6$ GeV/$c$. Theoretical calculations provide a good description of the measurements, within uncertainties.

   nucl-exhep-exPLB(2017)·250 citations
5. 05*

   Event-Shape Engineering and Jet Quenching

   Peter Christiansen🇸🇪

   Event-Shape Engineering (ESE) is a tool that enables some control of the initial geometry in heavy-ion collisions in a similar way as the centrality enables some control of the number of participants. Utilizing ESE, the path length in and out-of plane can be varied while keeping the medium properties (centrality) fixed. In this proceeding it is argued that this provides additional experimental information about jet quenching. Finally, it is suggested that if ESE studies are done in parallel for light and heavy quarks one can determine, in a model independent way, if the path-length dependence of their quenching differs.

   ↳ hep-phnucl-exJ.Phys.Conf.Ser.(2016)·10 citations
6. 06*

   Proton-skins in momentum space and neutron-skins in coordinate space in heavy nuclei

   Bao-Jun Cai🇺🇸 · Bao-An Li🇺🇸 · Lie-Wen Chen🇨🇳

   Neutron-skins in coordinate space and proton-skins in momentum space are predicted to coexist in heavy nuclei and their correlation is governed by Liouville's theorem and Heisenberg's uncertainty principle. An analysis of their correlation within a further extended Thomas-Fermi (ETF${}^{+}$) approximation incorporating effects of nucleon short-range correlations reveals generally that protons move faster than neutrons in neutron-skins of heavy nuclei.

   ↳ nucl-thastro-ph.SRnucl-exPRC(2016)·21 citations
7. 07*

   Measurement of forward-backward multiplicity correlations in lead-lead, proton-lead and proton-proton collisions with the ATLAS detector

   ATLAS Collaboration

   Two-particle pseudorapidity correlations are measured in $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV Pb+Pb, $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV $p$+Pb, and $\sqrt{s}$ = 13 TeV $pp$ collisions at the LHC, with total integrated luminosities of approximately 7 $\mu {\mathrm{b}}^{-1}$, 28 ${\mathrm{nb}}^{-1}$, and 65 ${\mathrm{nb}}^{-1}$, respectively. The correlation function $C_{\mathrm{N}}({\eta }_1,{\eta }_2)$ is measured as a function of event multiplicity using charged particles in the pseudorapidity range $|\eta |<2.4$. The correlation function contains a significant short-range component, which is estimated and subtracted. After removal of the short-range component, the shape of the correlation function is described approximately by $1+⟨a_1^2⟩{\eta }_1{\eta }_2$ in all collision systems over the full multiplicity range. The values of $\sqrt{⟨a_1^2⟩}$ are consistent between the opposite-charge pairs and same-charge pairs, and for the three collision systems at similar multiplicity. The values of $\sqrt{⟨a_1^2⟩}$ and the magnitude of the short-range component both follow a power-law dependence on the event multiplicity. The $\eta$ distribution of the short-range component, after symmetrizing the proton and lead directions in $p$+Pb collisions, is found to be smaller than that in $pp$ collisions with comparable multiplicity.

   ↳ hep-exnucl-exPRC(2017)·54 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.