Tue·May 31, 2016Tuesday·May 31, 2016

1. 01*

   Observation of the 2${}^{+}$ isomer in ${}^{52}$Co

   S.E.A. Orrigo🇪🇸 · B. Rubio🇪🇸 · W. Gelletly🇬🇧 · B. Blank🇫🇷 · Y. Fujita🇯🇵 · J. Giovinazzo🇫🇷 · J. Agramunt🇪🇸 · A. Algora🇪🇸 · P. Ascher🇫🇷 · B. Bilgier🇹🇷 · L. Cáceres🇫🇷 · R.B. Cakirli🇹🇷 and 16 other authors

   We report the first observation of the 2${}^{+}$ isomer in ${}^{52}$Co, produced in the $\beta$ decay of the 0${}^{+}$, ${}^{52}$Ni ground state. We have observed three $\gamma$-rays at 849, 1910, and 5185 keV characterizing the $\beta$ de-excitation of the isomer. We have measured a half-life of 102(6) ms for the isomeric state. The Fermi and Gamow-Teller transition strengths for the $\beta$ decay of ${}^{52m}$Co to ${}^{52}$Fe have been determined. We also add new information on the $\beta$ decay of the 6${}^{+}$, ${}^{52}$Co ground state, for which we have measured a half-life of 112(3) ms.

   nucl-exPRC(2016)·10 citations
2. 02*

   Asymmetric vector mesons produced in nuclear collisions

   I.M. Dremin🇷🇺 · V.A. Nechitailo🇷🇺

   It is argued that the experimentally observed phenomenon of asymmetric shapes of vector mesons produced in nuclear media during high energy nucleus-nucleus collisions can be explained as Fano-Feshbach resonances. It has been observed that the mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape with some excess in the low-mass wing of the resonance. It is clear that the whole phenomenon is related to some interaction with the nuclear medium. Moreover, it can be further detalized in quantum mechanics as the interference of direct and continuum states in Fano-Feshbach effect. To reveal the nature of the interaction it is proposed to use a phenomenological model of the additional contribution due to Cherenkov gluons. They can be created because of the excess of the refractivity index over 1 just in the low-mass wing as required by the classical Cherenkov treatment. In quantum mechanics, this requirement is related to the positive real part of the interaction amplitude in this wing. The corresponding parameters are found from the comparison with $\rho$-meson data and admit reasonable explanation.

   ↳ hep-phhep-exnucl-exnucl-thEPJA(2016)·0 citations
3. 03*

   Solving the $R_{AA}\otimes v_2$ puzzle

   Jacquelyn Noronha-Hostler🇺🇸

   For the past ten years $R_{AA}(p_T)$, the nuclear modification factor that encodes the suppression of high $p_T$ particles due to energy loss within the medium was fairly well described by many theoretical models. However, the same models systematically under-predicted the high $p_T$ elliptic flow, $v_2$, which is experimentally measured as the correlation between soft and hard hadrons. All previous calculations neglected the effect of event-by-event fluctuations of an expanding viscous hydrodynamical background as well as the soft-hard flow harmonic correlations in the experimentally measured $v_2$. In this talk I show how event-by-event viscous hydrodynamics (computed using the v-USPhydro code) coupled to an energy loss model (BBMG) is able to simultaneously describe soft physics observables as well as the high-$p_T$ $R_{AA}$ and $v_2$. Suggestions for future more differential calculations at the LHC run2 are made to explore soft-hard flow correlations.

   ↳ nucl-thhep-phnucl-exJ.Phys.Conf.Ser.(2016)·2 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.