Wed·Aug 27, 2014Wednesday·August 27, 2014

1. 01*

   Short Range Correlations at Large xbj through Inclusive Electron-nucleus Scattering

   Zhihong Ye🇺🇸

   The experiment, E08-014, in Hall-A at Jefferson Lab aims to study the short-range correlations (SRC) which are necessary to explain the nuclear strength absent in the mean field theory. The cross sections for ${}^2\mathrm{H}$, ${}^3\mathrm{He}$, ${}^4\mathrm{He}$, ${}^{12}\mathrm{C}$, ${}^{40}\mathrm{Ca}$ and ${}^{48}\mathrm{Ca}$, were measured via inclusive quasielastic electron scattering from these nuclei in a ${\mathrm{Q}}^2$ range between 0.8 and $2.8(GeV/c{)}^2$ for $x_{bj}>1$. The cross section ratios of heavy nuclei to ${}^2\mathrm{H}$ were extracted to study two-nucleon SRC for $1<x_{bj}<2$, while the study of three-nucleon SRC was carried out from the cross section ratios of heavy nuclei to ${}^3\mathrm{He}$ for $x_{bj}\ge 2$. Meanwhile, the isospin dependence in SRCs has also been examined through the cross section ratio of ${}^{48}\mathrm{Ca}$ and ${}^{40}\mathrm{Ca}$.

   nucl-ex4 citations
2. 02*

   Shell-gap reduced level densities in ${}^{89,90}$Y

   M. Guttormsen🇳🇴 · A.C. Larsen🇳🇴 · F.L. Bello Garrote🇳🇴 · Y. Byun · T.K. Eriksen🇳🇴 · F. Giacoppo🇳🇴 · A. Görgen🇳🇴 · T.W. Hagen🇳🇴 · M. Klintefjord🇳🇴 · H.T. Nyhus · T. Renstrøm🇳🇴 · S.J. Rose🇳🇴 and 5 other authors

   Particle-$\gamma$ coincidences from the ${}^{89}$Y($p,p^{\prime }\gamma$)${}^{89}$Y and ${}^{89}$Y($d,p\gamma$)${}^{90}$Y reactions were utilized to obtain $\gamma$-ray spectra as function of excitation energy. The Oslo method was used to extract the level density from the particle-$\gamma$ coincidence matrices. The impact of the $N=50$ shell closure on the level densities is discussed within the framework of a combinatorial quasi-particle model.

   nucl-exnucl-thPRC(2014)·13 citations
3. 03*

   Level densities and thermodynamical properties of Pt and Au isotopes

   F. Giacoppo🇳🇴 · F. L. Bello Garrote🇳🇴 · L. A. Bernstein🇺🇸 · D. L. Bleuel🇺🇸 · T. K. Eriksen🇳🇴 · R. B. Firestone🇺🇸 · A. Görgen🇳🇴 · M. Guttormsen🇳🇴 · T. W. Hagen🇳🇴 · B. V. Kheswa🇳🇴 · M. Klintefjord🇳🇴 · P. E. Koehler🇳🇴 and 6 other authors

   The nuclear level densities of ${}^{194-196}$Pt and ${}^{197,198}$Au below the neutron separation energy have been measured using transfer and scattering reactions. All the level density distributions follow the constant-temperature description. Each group of isotopes is characterized by the same temperature above the energy threshold corresponding to the breaking of the first Cooper pair. A constant entropy excess $\Delta S=1.9$ and $1.1$ $k_B$ is observed in ${}^{195}$Pt and ${}^{198}$Au with respect to ${}^{196}$Pt and ${}^{197}$Au, respectively, giving information on the available single-particle level space for the last unpaired valence neutron. The breaking of nucleon Cooper pairs is revealed by sequential peaks in the microcanonical caloric curve.

   nucl-exnucl-thPRC(2014)·13 citations
4. 04*

   Hoyle band and $\alpha$ condensation in ${}^{12}\mathrm{C}$

   Y. Funaki🇯🇵

   The excited states in ${}^{12}\mathrm{C}$ are investigated by using an extended version of the so-called Tohsaki-Horiuchi- Schuck-Röpke (THSR) wave function, where both the $3\alpha$ condensate and ${}^8\mathrm{Be}+\alpha$ cluster asymptotic configurations are included. A new method is also used to resolve spurious continuum coupling with physical states. We focus on the structures of the "Hoyle band" states, $2_2^{+}$, and $4_2^{+}$ states, which are recently observed above the Hoyle state and of the $0_3^{+}$ and $0_4^{+}$ states, which are also quite recently identified in experiment. Their resonance parameters and decay properties are reasonably reproduced. All these states have gaslike configurations of the $3\alpha$ clusters with larger root mean square radii than that of the Hoyle state. The Hoyle band is not simply considered to be the ${}^8\mathrm{Be}(0^{+})+\alpha$ rotation as suggested by previous cluster model calculations, nor to be a rotation of a rigid-body triangle-shaped object composed of the $3\alpha$ particles. This is mainly due to the specificity of the Hoyle state, which has the $3\alpha$ condensate structure and gives a rise to the $0_3^{+}$ state with a prominent ${}^8\mathrm{Be}(0^{+})+\alpha$ structure as a result of very strong monopole excitation from the Hoyle state.

   ↳ nucl-thnucl-exPRC(2015)·78 citations
5. 05*

   Tests of Lorentz symmetry in single beta decay

   Jorge S. Diaz🇩🇪

   Low-energy experiments studying single beta decay can serve as sensitive probes of Lorentz invariance that can complement interferometric searches for deviations from this spacetime symmetry. Experimental signatures of a dimension-three operator for Lorentz violation that are unobservable in neutrino oscillations are described for the decay the polarized and unpolarized neutrons as well as for measurements of the spectral endpoint in beta decay.

   ↳ hep-phhep-exnucl-exAdv.High Energy Phys.(2014)·25 citations
6. 06*

   Measurement of azimuthal correlations between D mesons and charged hadrons with ALICE at the LHC

   Fabio Colamaria (on behalf of the ALICE Collaboration)🇮🇹

   The comparison of angular correlations between charmed mesons and charged hadrons produced in pp, p-Pb and Pb-Pb collisions can give insight into the mechanisms through which charm quarks lose energy in a QGP medium, produced in ultra-relativistic heavy-ion collisions, and can help to recognize possible modifications of their hadronization induced by the presence of the QGP. The analysis of pp and p-Pb data and the comparison with predictions from pQCD calculations, besides constituting the necessary reference for interpreting Pb-Pb data, can provide relevant information on charm production and fragmentation processes. In addition, possible differences between the results from pp and p-Pb collisions can give information on the presence of cold nuclear matter effects, affecting the charm production and hadronization in the latter collision system. A study of azimuthal correlations between D${}^0$, D${}^{+}$, and D${}^{\ast +}$ mesons and charged hadrons in pp collisions at $\sqrt{s}$ = 7 TeV and p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV are presented. D mesons were reconstructed from their hadronic decays at central rapidity in the transverse-momentum range $3\le p_{\mathrm{T}}^{\mathrm{D}}\le 16$ GeV/$c$ and were correlated to charged particles reconstructed in the pseudorapidity range $|\eta |<0.8$. Perspectives for the measurement in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV will also be presented.

   ↳ hep-exnucl-exEPJ Web Conf.(2014)·5 citations
7. 07*

   Extrapolations of nuclear binding energies from new linear mass relations

   D. Hove · A.S. Jensen · K. Riisager

   We present a method to extrapolate nuclear binding energies from known values for neighbouring nuclei. We select four specific mass relations constructed to eliminate smooth variation of the binding energy as function nucleon numbers. The fast odd-even variations are avoided by comparing nuclei with same parity. The mass relations are first tested and shown to either be rather accurately obeyed or revealing signatures of quickly varying structures. Extrapolations are initially made for a nucleus by applying each of these relations. Very reliable estimates are then produced either by an average or by choosing the extrapolation where the smoothest structures enter. Corresponding mass relations for $Q_{\alpha }$ values are used to study the general structure of super-heavy elements. A minor neutron shell at $N=152$ is seen, but no sign of other shell structures are apparent in the super-heavy region. Accuracies are typically substantially better than $0.5$~MeV.

   ↳ nucl-thnucl-exPRC(2013)·4 citations
8. 08*

   Decay Law of Relativistic Particles: Quantum Theory Meets Special Relativity

   K. Urbanowski🇵🇱

   Late time properties of moving relativistic particles are studied. Within the proper relativistic treatment of the problem we find decay curves of such particles and we show that late time deviations of the survival probability of these particles from the exponential form of the decay law, that is the transition times region between exponential and non-expo\-nen\-tial form of the survival amplitude, occur much earlier than it follows from the classical standard approach boiled down to replace time $t$ by $t/{\gamma }_L$ (where ${\gamma }_L$ is the relativistic Lorentz factor) in the formula for the survival probability. The consequence is that fluctuations of the corresponding decay curves can appear much earlier and much more unstable particles have a chance to survive up to these times or later. It is also shown that fluctuations of the instantaneous energy of the moving unstable particles has a similar form as the fluctuations in the particle rest frame but they are seen by the observer in his rest system much earlier than one could expect replacing $t$ by $t/{\gamma }_L$ in the corresponding expressions for this energy and that the amplitude of these fluctuations can be even larger than it follows from the standard approach. All these effects seems to be important when interpreting some accelerator experiments with high energy unstable particles and the like (possible connections of these effects with GSI anomaly are analyzed) and some results of astrophysical observations.

   ↳ hep-phastro-ph.HEhep-thnucl-ex+1PLB(2014)·33 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.