Mon·Jan 25, 2016Monday·January 25, 2016

1. 01*

   Scaling properties of the mean multiplicity and pseudorapidity density in $e^{-}+e^{+}$, $e^{\pm }$+p, p($\bar{\mathrm{p}}$)+p, p+A and A+A(B) collisions

   Roy A. Lacey (1,2)🇺🇸 · Peifeng Liu (2)🇺🇸 · Niseem Magdy (1)🇺🇸 · M.Csanád (1,3)🇺🇸 · B. Schweid (2)🇺🇸 · N. N. Ajitanand (1)🇺🇸 · J. Alexander (1)🇺🇸 · R. Pak (4) ((1) Department of Chemistry, Stony Brook University, Stony Brook, NY, USA (2) Dept. of Physics, Stony Brook University, Stony Brook, NY, USA (3) Eotvos University, Department of Atomic Physics, Budapest, Hungary (4) Brookhaven National Laboratory, Upton, New York, USA)🇺🇸

   The pseudorapidity density (dN/deta) for p+p, p+A and A+A(B) collisions, and the mean multiplicity <Nch> for ee, ep, and p+p collisions, are studied for an inclusive range of beam energies (Root_s). Characteristic scaling patterns are observed for both dN/deta and <Nch>, consistent with a thermal particle production mechanism for the bulk of the soft particles produced in all of these systems. They also validate an essential role for quark participants in these collisions. The scaled values for dN/deta and <Nch> are observed to factorize into contributions which depend on log(Root_s) and the number of nucleon or quark participant pairs (Npp). Quantification of these contributions give expressions which serve to systematize dN/deta and <Nch> measurements spanning nearly four orders of magnitude in Root_s, and to predict their values as a function of Root_s and Npp.

   nucl-exhep-exhep-phnucl-thUniverse(2018)·36 citations
2. 02*

   $N^{\ast }$ decays to $N\omega$ from new data on $\gamma p\to \omega p$

   I. Denisenko🇩🇪 · A.V. Anisovich🇩🇪 · V. Crede🇺🇸 · H. Eberhardt🇩🇪 · E. Klempt🇩🇪 · V.A. Nikonov🇩🇪 · A.V. Sarantsev🇩🇪 · H. Schmieden🇩🇪 · U. Thoma🇩🇪 · A. Wilson🇩🇪

   Data on the reaction $\gamma p\to \omega p$ with $\omega \to {\pi }^0\gamma$, taken with unpolarized or polarized beams in combination with an unpolarized or polarized proton-target, were analyzed within the Bonn-Gatchina (BnGa) partial wave analysis. Differential cross sections, several spin density matrix elements, the beam asymmetry $\Sigma$, the normalized helicity difference $E$, and the correlation $G$ between linear photon and longitudinal target polarization were included in a large data base on pion and photo-induced reactions. The data on $\omega$ photoproduction are used to determine twelve $N^{\ast }\to N\omega$ branching ratios; most of these are determined for the first time.

   nucl-exPLB(2016)·30 citations
3. 03*

   Effect of cluster-shell competition of ${}^{12}$C on $E0$ transitions in ${}^{16}$O

   H. Matsuno🇯🇵 · N. Itagaki🇯🇵

   In ${}^{16}$O, we investigate the relation between the $E0$ monopole transition matrix elements and cluster-shell competition using antisymmetrized quasi cluster model (AQCM), where the dissolution of $alpha$ clusters into quasi clusters due to the effect of the spin-orbit force is introduced. We focus on the structure change when the strength of the spin-orbit force is varied. The ground state dominantly has a compact four $alpha$ structure (doubly magic structure of the $p$ shell), which is rather independent of the strength. However the first excited state ($0_2^{+}$) has ${}^{12}$C$+alpha$ cluster structure and this state is largely affected by the increase of the strength; the subclosure configuration of the $p_{3/2}$ shell for the ${}^{12}$C cluster part becomes more important than three $alpha$ configuration. The $E0$ transition from the ground state with compact four $alpha$ configuration to the $0_2^{+}$ state with ${}^{12}$C$+alpha$ cluster configuration is suppressed when increasing the spin-orbit strength. Although the $E0$ operator itself does not have the spin dependence, the matrix element is sensitive to the difference of intrinsic spin structures of the two states. The $E0$ transition characterizes the persistence of four $alpha$ structure in the $0_2^{+}$ state.

   ↳ nucl-thnucl-ex1 citation
4. 04*

   Much ado about Zero

   Asis Kumar Chaudhuri🇮🇳

   A brief historical introduction for the enigmatic number Zero is given. The discussions are for popular consumption.

   ↳ math.HOhep-phnucl-exnucl-th+10 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.