Nuclear Theory·nucl-th
4 papers—2 primary·2 cross-listed
In this contribution, we present the open-flavor strong decays of light baryons computed within the framework of quark model. The transition amplitudes are computed using a modified operator, where a mechanism strange suppression is taken into account. Also we discus the strange suppression within an extension of the quark model.
Ling-Yun Dai🇩🇪 · Johann Haidenbauer🇩🇪 · Ulf-G. Meißner🇩🇪
Results for the antinucleon-nucleon () interaction obtained at next-to-next-to-next-to-leading order in chiral effective field theory (EFT) are reported. A new local regularization scheme is used for the pion-exchange contributions that has been recently suggested and applied in a pertinent study of the force within chiral EFT. Furthermore, an alternative strategy for estimating the uncertainty is utilized that no longer depends on a variation of the cutoffs. The low-energy constants associated with the arising contact terms are fixed by a fit to the phase shifts and inelasticities provided by a phase-shift analysis of scattering data. An excellent description of the amplitudes is achieved at the highest order considered. Moreover, because of the quantitative reproduction of partial waves up to , there is also a nice agreement on the level of observables. Specifically, total and integrated elastic and charge-exchange cross sections agree well with the results from the partial-wave analysis up to laboratory energies of MeV, while differential cross sections and analyzing powers are described quantitatively up to - MeV. The low-energy structure of the amplitudes is also considered and compared to data from antiprotonic hydrogen.
We have measured the total kinetic energy release (TKE), its variance and associated fission product distributions for the neutron induced fission of 232Th and 235U for En = 2 - 90 MeV. The neutron energies were determined on an event by event basis by time of flight measurements with the white spectrum neutron beam from LANSCE. The TKE decreases non-linearly with increasing neutron energy for both systems, while the TKE variances are sensitive indicators of nth chance fission. The associated fission product distributions show the decrease in TKE with increasing beam energy that is due to the increasing probability of symmetric fission, which has a lower associated TKE, and the decreasing TKE associated with asymmetric fission, presumably due to the decreasing importance of the A = 132 shell structures.
Maurício Hippert🇧🇷 · Eduardo S. Fraga🇧🇷
Statistical moments of particle multiplicities in heavy-ion collision experiments are an important probe in the exploration of the phase diagram of strongly interacting matter and, particularly, in the search for the QCD critical end point. In order to appropriately interpret experimental measures of these moments, however, it is necessary to understand the role of experimental limitations, as well as background contributions, providing expectations on how critical behavior should be affected by them. We here present a framework for calculating moments of particle multiplicities in the presence of correlations of both critical and spurious origins. We also include effects from resonance decay and a limited acceptance window, as well as detector efficiency. Although we focus on second-order moments, for simplicity, an extension to higher-order moments is straightforward.
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