Thu·Jan 15, 2015Thursday·January 15, 2015

1. 01*

   Search for unbound 15Be states in the 3n+12Be channel

   A. N. Kuchera🇺🇸 · A. Spyrou🇺🇸 · J. K. Smith🇺🇸 · T. Baumann🇺🇸 · G. Christian🇺🇸 · P. A. DeYoung🇺🇸 · J. E. Finck🇺🇸 · N. Frank🇺🇸 · M. D. Jones🇺🇸 · Z. Kohley🇺🇸 · S. Mosby🇺🇸 · W. A. Peters🇺🇸 · M. Thoennessen🇺🇸

   15Be is expected to have low-lying 3/2+ and 5/2+ states. A first search did not observe the 3/2+ [A. Spyrou et al., Phys. Rev. C 84, 044309 (2011)], however, a resonance in 15Be was populated in a second attempt and determined to be unbound with respect to 14Be by 1.8(1) MeV with a tentative spin-parity assignment of 5/2+ [J. Snyder et al., Phys. Rev. C 88, 031303(R) (2013)]. Search for the predicted 15Be 3/2+ state in the three-neutron decay channel. A two-proton removal reaction from a 55 MeV/u 17C beam was used to populate neutron-unbound states in 15Be. The two-, three-, and four-body decay energies of the 12Be + neutron(s) detected in coincidence were reconstructed using invariant mass spectroscopy. Monte Carlo simulations were performed to extract the resonance and decay properties from the observed spectra. The low-energy regions of the decay energy spectra can be described with the first excited unbound state of 14Be (E_x=1.54 MeV, E_r=0.28 MeV). Including a state in 15Be that decays through the first excited 14Be state slightly improves the fit at higher energies though the cross section is small. A 15Be component is not needed to describe the data. If the 3/2+ state in 15Be is populated, the decay by three-neutron emission through 14Be is weak, less than or equal to 11% up to 4 MeV. In the best fit, 15Be is unbound with respect to 12Be by 1.4 MeV (unbound with respect to $14Be by 2.66 MeV) with a strength of 7%.

   nucl-exPRC(2015)·14 citations
2. 02*

   $\beta$-delayed $\gamma$-proton decay in ${}^{56}$Zn: analysis of the charged-particle spectrum

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

   A study of the $\beta$ decay of the proton-rich $T_z$ = -2 nucleus ${}^{56}$Zn has been reported in a recent publication. A rare and exotic decay mode, $\beta$-delayed $\gamma$-proton decay, has been observed there for the first time in the $fp$ shell. Here we expand on some of the details of the data analysis, focussing on the charged particle spectrum.

   nucl-exActa Phys.Polon.B(2015)·1 citation
3. 03*

   Competition between $\beta$-delayed proton and $\beta$-delayed $\gamma$ decay of the exotic $T_z$ = -2 nucleus ${}^{56}$Zn and fragmentation of the IAS

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

   A very exotic decay mode at the proton drip-line, $\beta$-delayed $\gamma$-proton decay, has been observed in the $\beta$ decay of the $T_z$ = -2 nucleus ${}^{56}$Zn. Three $\gamma$-proton sequences have been observed following the $\beta$ decay. The fragmentation of the IAS in ${}^{56}$Cu has also been observed for the first time. The results were reported in a recent publication. At the time of publication the authors were puzzled by the competition between proton and $\gamma$ decays from the main component of the IAS. Here we outline a possible explanation based on the nuclear structure properties of the three nuclei involved, namely ${}^{56}$Zn, ${}^{56}$Cu and ${}^{55}$Ni, close to the doubly magic nucleus ${}^{56}$Ni. From the fragmentation of the Fermi strength and the excitation energy of the two populated 0${}^{+}$ states we could deduce the off-diagonal matrix element of the charge-dependent part of the Hamiltonian responsible for the mixing. These results are compared with the decay of ${}^{55}$Cu with one proton less than ${}^{56}$Zn. For completeness we summarise the results already published.

   nucl-exJPS Conf.Proc.(2015)·1 citation
4. 04*

   Subleading harmonic flows in hydrodynamic simulations of heavy ion collisions

   Aleksas Mazeliauskas🇺🇸 · Derek Teaney🇺🇸

   We perform a principal component analysis (PCA) of $v_3(p_T)$ in event-by-event hydrodynamic simulations of Pb+Pb collisions at the Large Hadron Collider (LHC). The PCA procedure identifies two dominant contributions to the two-particle correlation function, which together capture 99.9\% of the squared variance. We find that the subleading flow (which is the largest source of flow factorization breaking in hydrodynamics) is predominantly a response to the radial excitations of a third-order eccentricity. We present a systematic study of the hydrodynamic response to these radial excitations in 2+1D viscous hydrodynamics. Finally, we construct a good geometrical predictor for the orientation angle and magnitude of the leading and subleading flows using two Fourier modes of the initial geometry.

   ↳ nucl-thhep-phnucl-exPRC(2015)·62 citations
5. 05*

   Neutrino-Nucleus Interactions at the LBNF Near Detector

   Ulrich Mosel🇩🇪

   The reaction mechanisms for neutrino interactions with an ${}^{40}Ar$ nucleus with the LBNF flux are calculated with the Giessen-Boltzmann-Uehling-Uhlenbeck (GiBUU) transport-theoretical implementation of these interactions. Quasielastic scattering, many-body effects, pion production and absorption and Deep Inelastic Scattering are discussed; they all play a role at the LBNF energies and are experimentally entangled with each other. Quasielastic scattering makes up for only about 1/3 of the total cross section whereas pion production channels make up about 2/3 of the total. This underlines the need for a consistent description of the neutrino-nucleus reaction that treats all channels on an equal, consistent footing. The results discussed here can also serve as useful guideposts for the Intermediate Neutrino Program.

   ↳ hep-exhep-phnucl-exnucl-thAIP Conf.Proc.(2015)·4 citations
6. 06*

   The Relativistic Green's function model and charged-current inclusive neutrino-nucleus scattering at T2K kinematics

   Andrea Meucci🇮🇹 · Carlotta Giusti🇮🇹

   We compare the results of the relativistic Green's function model with the experimental data of the charged-current inclusive differential neutrino-nucleus cross sections published by the T2K Collaboration. The model, which is able to describe both MINER$\nu$A and MiniBooNE charged-current quasielastic scattering data, underpredicts the inclusive T2K cross sections.

   ↳ nucl-thhep-phnucl-exPRD(2015)·15 citations
7. 07*

   $(h_{11/2}{)}^2$ alignments in neutron-rich ${}^{132}$Ba with negative-parity pairs

   Yang Lei🇨🇳 · Zhengyu Xu

   The shell-model collective-pair truncation with negative-parity pairs is adopted to study the $(h_{11/2}{)}^2$ alignment in ${}^{132}$Ba. The proton $(h_{11/2}{)}^2$-alignment state is predicted as an $E\sim 4.6$ MeV and $\tau \sim 0.5\mu$s isomer with relatively strong E3 decay channels. The oblately deformed neutron $(h_{11/2}{)}^{-2}$ alignment in the yrast band and four negative-parity bands are confirmed, even although two of these negative-parity bands favor the prolate deformation, which directly manifests the $\gamma$ unstability of ${}^{132}$Ba.

   ↳ nucl-thnucl-exPRC(2015)·7 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.