Mon·Apr 13, 2015Monday·April 13, 2015

1. 01*

   Search for Neutrinoless Double-Beta Decay of ${}^{130}$Te with CUORE-0

   K. Alfonso · D.R. Artusa · F.T. Avignone III · O. Azzolini · M. Balata · T.I. Banks · G. Bari · J.W. Beeman · F. Bellini · A. Bersani · M. Biassoni · C. Brofferio and 106 other authors

   We report the results of a search for neutrinoless double-beta decay in a 9.8~kg$\cdot$yr exposure of ${}^{130}$Te using a bolometric detector array, CUORE-0. The characteristic detector energy resolution and background level in the region of interest are $5.1\pm 0.3\mathrm{keV}$ FWHM and $0.058\pm 0.004(stat.)\pm 0.002(syst.)$~counts/(keV$\cdot$kg$\cdot$yr), respectively. The median 90%~C.L. lower-limit sensitivity of the experiment is $2.9\times 10^{24}\mathrm{yr}$ and surpasses the sensitivity of previous searches. We find no evidence for neutrinoless double-beta decay of ${}^{130}$Te and place a Bayesian lower bound on the decay half-life, $T_{1/2}^{0\nu }>$~$2.7\times 10^{24}\mathrm{yr}$ at 90%~C.L. Combining CUORE-0 data with the 19.75~kg$\cdot$yr exposure of ${}^{130}$Te from the Cuoricino experiment we obtain $T_{1/2}^{0\nu }>4.0\times 10^{24}\mathrm{yr}$ at 90%~C.L.~(Bayesian), the most stringent limit to date on this half-life. Using a range of nuclear matrix element estimates we interpret this as a limit on the effective Majorana neutrino mass, $m_{\beta \beta }<270$ -- $760\mathrm{meV}$.

   nucl-exhep-exphysics.ins-detPRL(2015)·304 citations
2. 02*

   Fission barrier, damping of shell correction and neutron emission in the fission of A$\sim$200

   K. Mahata🇮🇳 · S. Kailas🇮🇳 · S. S. Kapoor

   Decay of ${}^{210}$Po compound nucleus formed in light and heavy-ion induced fusion reactions has been analyzed simultaneously using a consistent prescription for fission barrier and nuclear level density incorporating shell correction and its damping with excitation energy. Good description of all the excitation functions have been achieved with a fission barrier of 21.9 $\pm$ 0.2 MeV. For this barrier height, the predicted statistical pre-fission neutrons in heavy-ion fusion-fission are much smaller than the experimental values, implying the presence of dynamical neutrons due to dissipation even at these low excitation energies ($\sim$ 50~MeV) in the mass region A $\sim$ 200. When only heavy-ion induced fission excitation functions and the pre-fission neutron multiplicities are included in the fits, the deduced best fit fission barrier depends on the assumed fission delay time during which dynamical neutrons can be emitted. A fission delay of (0.8 $\pm$ 0.1 )$\times 10^{-19}$ s has been estimated corresponding to the above fission barrier height assuming that the entire excess neutrons over and above the statistical model predictions are due to the dynamics. The present observation has implication on the study of fission time scale/ nuclear viscosity using neutron emission as a probe.

   nucl-exnucl-thPRC(2015)·31 citations
3. 03*

   Cross-checking the symmetry energy at high densities

   Gao-Chan Yong🇨🇳

   The nuclear symmetry energy determines the birth of neutron stars and the elementary nucleosynthesis in the universe. To constrain the nuclear symmetry energy, besides the studies in astrophysics, many terrestrial nuclear experiments are being carried out using a wide variety of advanced new facilities. In this paper, by cross-checking two unrelated experimental measurements using the newly updated transport model, we obtained a slightly soft symmetry energy at supra-saturation nuclear densities. While extrapolating to low nuclear densities, this result is compatible with the recent finding by comparing the available data on the electric dipole polarizability with the theoretical predictions. Our finding is expected to push the studies of nuclear physics and astrophysics forward.

   ↳ nucl-thnucl-exPRC(2016)·36 citations
4. 04*

   Robust correlations between quadrupole moments of low-lying $2^{+}$ states within random-interaction ensembles

   Y. Lei🇨🇳

   In the random-interaction ensembles, three proportional correlations between quadrupole moments of the first two $I^{\pi }=2^{+}$ states robustly emerge, including $Q(2_1^{+})=\pm Q(2_2^{+})$ correlations consistently with realistic nuclear survey, and the $Q(2_2^{+})=-\frac{3}{7}Q(2_1^{+})$ correlation, which is only observed in the $sd$-boson space. These correlations can be microscopically characterized by the rotational SU(3) symmetry and quadrupole vibrational U(5) limit, respectively, according to the Elliott model and the $sd$-boson mean-field theory. The anharmonic vibration may be another phenomenological interpretation for the $Q(2_1^{+})=-Q(2_2^{+})$ correlation, whose spectral evidence, however, is insufficient.

   ↳ nucl-thnucl-exPRC(2016)·7 citations
5. 05*

   Anomalous decay and scattering processes of the eta meson

   Bastian Kubis🇩🇪 · Judith Plenter🇩🇪

   We amend a recent dispersive analysis of the anomalous $\eta$ decay process $\eta \to {\pi }^{+}{\pi }^{-}\gamma$ by the effects of the $a_2$ tensor meson, the lowest-lying resonance that can contribute in the $\pi \eta$ system. While the net effects on the measured decay spectrum are small, they may be more pronounced for the analogous ${\eta }^{\prime }$ decay. There are nonnegligible consequences for the $\eta$ transition form factor, which is an important quantity for the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment. We predict total and differential cross sections, as well as a marked forward-backward asymmetry, for the crossed process $\gamma {\pi }^{-}\to {\pi }^{-}\eta$ that could be measured in Primakoff reactions in the future.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2015)·110 citations
6. 06*

   Lepton-pair production in ultraperipheral collisions at AFTER@LHC

   J.P. Lansberg🇫🇷 · L. Szymanowski🇵🇱 · J. Wagner🇵🇱

   We investigate the potentialities offered by the study of lepton-pair production in ultraperipheral collisions at a fixed-target experiment using the proton and ion LHC beams. In these collisions, exclusive or semi-exclusive lepton-pair production can be used as luminosity monitor as well as a check of the equivalent-photon approximation, via the measurement of the Bethe-Heitler cross section. It can also serve as a probe of the inner hadron structure via the measurement of the lepton-pair azimuthal asymmetry which is sensitive to the timelike virtual Compton scattering. We also briefly discuss the possibility offered by the study of eta(c) production. Finally, we outline the possibilities for lepton-pair production by Pomeron-Odderon fusion in exclusive pp and pA collisions.

   ↳ hep-phhep-exnucl-exnucl-thJHEP(2015)·22 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.