Thu·Aug 4, 2011Thursday·August 4, 2011

1. 01*

   Resolving the Axial Mass Anomaly in neutrino Scattering

   A. Bodek🇺🇸 · H.S. Budd🇺🇸 · M. E. Christy🇺🇸

   We present a parametrization of the observed enhancement in the transverse electron quasielastic (QE) response function for nucleons bound in carbon as a function of the square of the four momentum transfer (Q2) in terms of a correction to the magnetic form factors of bound nucleons. The parametrization should also be applicable to the transverse cross section in neutrino scattering. If the transverse enhancement originates from meson exchange currents (MEC), then it is theoretically expected that any enhancement in the longitudinal or axial contributions is small. We present the predictions of the "Transverse Enhancement" model (which is based on electron scattering data only) for the neutrino and anti-neutrino differential and total QE cross sections for nucleons bound in carbon. The 2Q2 dependence of the transverse enhancement is observed to resolve much of the long standing discrepancy ("Axial Mass Anomaly}) in the QE total cross sections and differential distributions between low energy and high energy neutrino experiments on nuclear targets.

   nucl-exhep-exhep-phnucl-thAIP Conf.Proc.(2012)·2 citations
2. 02*

   Higher-order anisotropic flows and dihadron correlations in Pb-Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV in a multiphase transport model

   Jun Xu🇺🇸 · Che Ming Ko🇺🇸

   Using a multiphase transport model that includes both initial partonic and final hadronic scatterings, we have studied higher-order anisotropic flows as well as dihadron correlations as functions of pseudorapidity and azimuthal angular differences between trigger and associated particles in Pb-Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV. With parameters in the model determined previously from fitting the measured multiplicity density of mid-pseudorapidity charged particles in central collisions and their elliptic flow in mid-central collisions, the calculated higher-order anisotropic flows from the two-particle cumulant method reproduce approximately those measured by the ALICE Collaboration, except at small centralities where they are slightly overestimated. Similar to experimental results, the two-dimensional dihadron correlations at most central collisions show a ridge structure at the near side and a broad structure at the away side. The short- and long-range dihadron azimuthal correlations, corresponding to small and large pseudorapidity differences, respectively, are studied for triggering particles with different transverse momenta and are found to be qualitatively consistent with experimental results from the CMS Collaboration. The relation between the short-range and long-range dihadron correlations with that induced by back-to-back jet pairs produced from initial hard collisions is also discussed.

   ↳ nucl-thhep-phnucl-exPRC(2011)·55 citations
3. 03*

   Shear-Viscosity to Entropy-Density Ratio from Giant Dipole Resonances in Hot Nuclei

   Nguyen Dinh Dang🇯🇵

   The Green-Kubo relation and fluctuation-dissipation theorem are employed to calculate the shear viscosity $\eta$ of a finite hot nucleus directly from the width and energy of the giant dipole resonance (GDR) of this nucleus. The ratio $\eta /s$ of shear viscosity $\eta$ to entropy density $s$ is extracted from the experimental systematics of the GDR in copper, tin and lead isotopes at finite temperature $T$. These empirical results are then compared with the predictions by several independent models, as well as with almost model-independent estimations. Based on these results, it is concluded that the ratio $\eta /s$ in medium and heavy nuclei decreases with increasing temperature $T$ to reach $(1.3-4)\times \hslash /(4\pi k_B)$ at $T=$ 5 MeV.

   ↳ nucl-thhep-phnucl-exPRC(2011)·27 citations
4. 04*

   A study of Lambda hypernuclei within the Skyrme-Hartree-Fock Model

   Neelam Guleria🇮🇳 · Shashi K.Dhiman🇮🇳 · Radhey Shyam🇮🇳

   We investigate the properties of the single Lambda hypernuclei within a Skyrme-Hartree-Fock (SHF) model. The parameters of the Skyrme type effective lambda-nucleon (Lambda N) interaction are obtained by fitting to the experimental Lambda binding energies of hypernuclei with masses spanning a wide range of the periodic table. Alternative parameter sets are also obtained by omitting nuclei below mass number 16 from the fitting procedure. The SHF calculations are performed for the binding energies of the Lambda single-particle states over a full mass range using the best fit parameter sets obtained in these fitting procedures and the results are compared with the available experimental data. The data show some sensitivity to the parameter sets obtained with or without including the nuclei below mass 16. The radii of the Lambda orbits in the hypernuclear ground states and the Lambda effective mass in nuclear matter show some dependence on different parameter sets. We present results for the total binding energy per baryon of the hypernuclei over a large mass region to elucidate their stability as a function of the baryon number. We have also employed the our best fit Lambda N parameter sets to investigate the role of hyperons in some key properties of neutron stars.

   ↳ nucl-thhep-phnucl-exNPA(2012)·50 citations
5. 05*

   Correlations of Heavy Quarks Produced at Large Hadron Collider

   Mohammed Younus🇮🇳 · Umme Jamil🇮🇳 · Dinesh K. Srivastava🇮🇳

   We study the correlations of heavy quarks produced in relativistic heavy ion collisions and find them to be quite sensitive to the effects of the medium and the production mechanisms. In order to put this on a quantitative footing, as a first step, we analyze the azimuthal, transverse momentum, and rapidity correlations of heavy quark-anti quark ($Q\overline{Q}$) pairs in $pp$ collisions at $\mathcal{O}$(${\alpha }_s^3$). This sets the stage for the identification and study of medium modification of similar correlations in relativistic collision of heavy nuclei at the Large Hadron Collider. Next we study the additional production of charm quarks in heavy ion collisions due to multiple scatterings, {\it viz.}, jet-jet collisions, jet-thermal collisions, and thermal interactions. We find that these give rise to azimuthal correlations which are quite different from those arising from prompt initial production at leading order and at next to leading order.

   ↳ hep-phhep-exnucl-exnucl-thJ.Phys.(2012)·7 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.