Thu·Aug 11, 2011Thursday·August 11, 2011

1. 01*

   Partial Decay Widths of Negative Parity Baryons in the 1/Nc Expansion

   C. Jayalath🇺🇸 · J. L. Goity🇺🇸 · E. Gonzalez de Urreta🇦🇷 · N. N. Scoccola🇦🇷

   The partial decay widths of lowest lying negative parity baryons belonging to the 70-plet of SU(6) are analyzed in the framework of the 1/Nc expansion The channels considered are those with single pseudo-scalar meson emission. The analysis is carried out to sub-leading order in 1/Nc and to first order in SU(3) symmetry breaking. Conclusions about the magnitude of SU(3) breaking effects along with predictions for some unknown or poorly determined partial decay widths of known resonances are obtained.

   ↳ nucl-thhep-phnucl-exPRD(2011)·17 citations
2. 02*

   Thermal Photons and Collective Flow at the Relativistic Heavy-Ion Collider

   H. van Hees🇩🇪 · C. Gale🇨🇦 · R. Rapp🇺🇸

   We update our calculations of thermal-photon production in nuclear collisions at the Relativistic Heavy-Ion Collider (RHIC). Specifically, we address the recent experimental observation of an elliptic flow of direct photons comparable in magnitude to that of pions, which is at variance with expectations based on quark-gluon plasma (QGP) dominated photon radiation. Our thermal emission rate is based on previous work, i.e., resummed leading-order QGP emission and in-medium hadronic rates in the confined phase. These rates are nearly degenerate at temperatures close to the expected QCD-phase change. The rates are convoluted over an improved elliptic-fireball expansion with transverse- and elliptic-flow fields quantitatively constrained by empirical light- and strange-hadron spectra. The resulting direct-photon spectra in central Au-Au collisions are characterized by hadron-dominated emission up to transverse momenta of ~2-3 GeV. The associated large elliptic flow in the hadronic phase mitigates the discrepancy with the measured photon-v2 compared to scenarios with QGP-dominated emission.

   ↳ hep-phnucl-exnucl-thPRC(2011)·191 citations
3. 03*

   Nuclear medium effects from hadronic atoms

   E. Friedman🇮🇱 · A. Gal🇮🇱

   The state of the art in the study of pionic, kaonic and Sigmionic atoms, along with the in-medium nuclear interactions deduced for these hadrons, is reviewed. A special emphasis is placed on recent developments in antikaon-nuclear physics, where a strongly attractive density dependent antikaon-nuclear potential of order 150-200 MeV in nuclear matter emerges by fitting K^- atom data. This has interesting repercussions on antikaon quasibound nuclear states, on the composition of strange hadronic matter and on kaon condensation in self bound hadronic systems.

   ↳ nucl-thhep-phnucl-ex2 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.