Fri·Nov 28, 2014Friday·November 28, 2014

1. 01*

   Measurement of the two-photon exchange contribution to the elastic $e^{\pm }p$ scattering cross sections at the VEPP-3 storage ring

   I. A. Rachek🇷🇺 · J. Arrington🇺🇸 · V. F. Dmitriev🇷🇺 · V. V. Gauzshtein🇷🇺 · R. E. Gerasimov🇷🇺 · A. V. Gramolin🇷🇺 · R. J. Holt🇺🇸 · V. V. Kaminskiy🇷🇺 · B. A. Lazarenko🇷🇺 · S. I. Mishnev🇷🇺 · N. Yu. Muchnoi🇷🇺 · V. V. Neufeld🇷🇺 and 8 other authors

   The ratio of the elastic $e^{+}p$ to $e^{-}p$ scattering cross sections has been measured precisely, allowing the determination of the two-photon exchange contribution to these processes. This neglected contribution is believed to be the cause of the discrepancy between the Rosenbluth and polarization transfer methods of measuring the proton electromagnetic form factors. The experiment was performed at the VEPP-3 storage ring at beam energies of 1.6 and 1.0 GeV and at lepton scattering angles between $15^{\circ }$ and $105^{\circ }$. The data obtained show evidence of a significant two-photon exchange effect. The results are compared with several theoretical predictions.

   nucl-exhep-exhep-phPRL(2015)·134 citations
2. 02*

   Excitation functions of ${}^{nat}$Pb(d,x)${}^{206,205,204,203,202}$Bi, ${}^{203cum,202m,201cum}$Pb and ${}^{202cum,201cum}$Tl reactions up to 50 MeV

   F. Ditrói🇭🇺 · F. Tárkányi🇭🇺 · S. Takács🇭🇺 · A. Hermanne🇧🇪 · A.V. Ignatyuk

   Cross-sections of deuteron induced nuclear reactions on lead were measured up to 50 MeV using the standard stacked foil irradiation technique and high resolution $\gamma$-ray spectrometry. Experimental cross-sections and derived integral yields are presented for the ${}^{nat}$Pb(d,x)${}^{206,205,204,203,202}$Bi, ${}^{203cum,202m,201cum}$Pb and ${}^{202cum,201cum}$Tl reactions. The experimental data were compared with the results from literature and with the data in the TENDL-2013 library (obtained with TALYS code). The cross-section data were analyzed also with the theoretical results calculated by using the ALICE-IPPPE-D and EMPIRE-D codes.

   nucl-exJournal of Radionalytical Nuclear Chemist…·0 citations
3. 03*

   Probing the momentum-dependence of the symmetry potential by the free n/p ratio of preequilibrium emission

   He-Lei Liu · Gao-Chan Yong🇨🇳 · De-Hua Wen🇨🇳

   Based on an isospin and momentum-dependent transport model, we studied the effect of momentum-dependent symmetry potential on the free neutron to proton ratio of preequilibrium nucleon emission. It is found that for ${}^{132}Sn{+}^{124}Sn$ reaction at 400 MeV/nucleon incident beam energy, free n/p ratio of preequilibrium nucleon emission mainly probe the momentum-dependence of symmetry potential at nucleon momentum around 400 $\sim$ 600 MeV/c. Whereas for 200 MeV/nucleon incident beam energy, this observable mainly probe the momentum-dependence of symmetry potential at nucleon momentum around 200 $\sim$ 400 MeV/c. To probe the symmetry energy/potential using free n/p ratio, not all the details of the momentum-dependence of the symmetry potential are important, the values of symmetry potential at only certain momentum range are crucial for an observable. It is important to input reasonable density- and momentum-dependence of the symmetry potential according to the magnitude of incident beam energy of heavy-ion collisions. The present experimental data on the symmetry potential are not enough for probing the density-dependent symmetry energy. More experimental data (such as nucleon and nuclei's scattering experiments at different nucleonic momenta and densities) on the symmetry potential are therefore needed to pin down the density-dependent symmetry energy.

   ↳ nucl-thnucl-exPRC(2015)·9 citations
4. 04*

   Charmonium Spectroscopy in Strong Magnetic Fields by QCD Sum Rules: S-Wave Ground States

   Sungtae Cho🇰🇷 · Koichi Hattori🇯🇵 · Su Houng Lee🇰🇷 · Kenji Morita🇯🇵 · Sho Ozaki🇰🇷

   We investigate quarkonium mass spectra in external constant magnetic fields by using QCD sum rules. We first discuss a general framework of QCD sum rules necessary for properly extracting meson spectra from current correlators computed in the presence of strong magnetic fields, that is, a consistent treatment of mixing effects caused in the mesonic degrees of freedom. We then implement operator product expansions for pseudoscalar and vector heavy-quark current correlators by taking into account external constant magnetic fields as operators, and obtain mass shifts of the lowest-lying bound states ${\eta }_c$ and $J/\psi$ in the static limit with their vanishing spatial momenta. Comparing results from QCD sum rules with those from hadronic effective theories, we find that the dominant origin of mass shifts comes from a mixing between ${\eta }_c$ and $J/\psi$ with a longitudinal spin polarization, accompanied by other subdominant effects such as mixing with higher excited states and continua.

   ↳ hep-phhep-latnucl-exnucl-thPRD(2015)·95 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.