Mon·Sep 14, 2015Monday·September 14, 2015

1. 01*

   Study of Charmonium Production in Asymmetric Nuclear Collisions by the PHENIX Experiment at RHIC

   Alexandre Lebedev (for the PHENIX Collaboartion)🇺🇸

   The measurement of quarkonia production in relativistic heavy ion collisions provides a powerful tool for studying the properties of the hot and dense matter created in these collisions. To be really useful, however, such measurements must cover a wide range of quarkonia states and colliding species. The PHENIX experiment at RHIC has successfully measured J/psi, psi-prime, chi_c and Upsilon production in different colliding systems at various energies. In this talk I will present recent results from the PHENIX collaboration on charmonium production in d+Au, Cu+Au and U+U collisions at 200 GeV/c.

   nucl-ex2 citations
2. 02*

   Contact-interaction Faddeev equation and, inter alia, proton tensor charges

   Shu-Sheng Xu🇨🇳 · Chen Chen🇨🇳 · Ian C.Cloet🇺🇸 · Craig D. Roberts🇺🇸 · Jorge Segovia🇪🇸 · Hong-Shi Zong🇨🇳

   A confining, symmetry-preserving, Dyson-Schwinger equation treatment of a vector-vector contact interaction is used to formulate Faddeev equations for the nucleon and Delta-baryon in which the kernel involves dynamical dressed-quark exchange and whose solutions therefore provide momentum-dependent Faddeev amplitudes. These solutions are compared with those obtained in the static approximation and with a QCD-kindred formulation of the Faddeev kernel. They are also used to compute a range of nucleon properties, amongst them: the proton's sigma-term; the large Bjorken-x values of separate ratios of unpolarised and longitudinally-polarised valence u- and d-quark parton distribution functions; and the proton's tensor charges, which enable one to directly determine the effect of dressed-quark electric dipole moments (EDMs) on neutron and proton EDMs.

   ↳ nucl-thhep-lathep-phnucl-exPRD(2015)·60 citations
3. 03*

   Chiral Three-Nucleon Interactions in Light Nuclei, Neutron-$\alpha$ Scattering, and Neutron Matter

   J. E. Lynn🇩🇪 · I. Tews🇩🇪 · J. Carlson🇺🇸 · S. Gandolfi🇺🇸 · A. Gezerlis🇨🇦 · K. E. Schmidt🇺🇸 · A. Schwenk🇩🇪

   We present quantum Monte Carlo calculations of light nuclei, neutron-$\alpha$ scattering, and neutron matter using local two- and three-nucleon ($3N$) interactions derived from chiral effective field theory up to next-to-next-to-leading order (N${}^2$LO). The two undetermined $3N$ low-energy couplings are fit to the ${}^4$He binding energy and, for the first time, to the spin-orbit splitting in the neutron-$\alpha$ $P$-wave phase shifts. Furthermore, we investigate different choices of local $3N$-operator structures and find that chiral interactions at N${}^2$LO are able to simultaneously reproduce the properties of $A=3,4,5$ systems and of neutron matter, in contrast to commonly used phenomenological $3N$ interactions.

   ↳ nucl-thnucl-exPRL(2016)·323 citations
4. 04*

   Production of strange and charmed baryons in pion induced reactions

   Sang-Ho Kim🇯🇵 · Atsushi Hosaka🇯🇵 · Hyun-Chul Kim🇰🇷 · Hiroyuki Noumi🇯🇵

   We study the strangeness and charm productions induced by the pion beam, i.e. the ${\pi }^{-}$p $\to$ $K^{\ast 0}\Lambda$ and ${\pi }^{-}$p $\to$ $D^{\ast -}{\Lambda }_c^{+}$ reactions, based on two different theoretical frameworks: an effective Lagrangian method and a Regge approach. In order to estimate the magnitude of the charm production relative to that of the strangeness production, we assume that the coupling constants for the charmed meson and baryon vertices are the same as those for the strangeness channel. We found that the total cross section for the charm production was about $10^3-10^6$ times smaller than that for the strangeness production, depending on theoretical approaches and kinematical regions. We also discuss each contribution to observables for both reactions. In general, the Regge approach explains the experimental data very well over the whole energy region.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2015)·33 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.