Nuclear Theory·nucl-th
4 papers—1 primary·3 cross-listed
In a single j-shell calculation we consider the effects of several different interactions on the values of Gamow-Teller (B(GT)'s) and magnetic moments. The interactions used are MBZE, J=0 pairing, J_{max} pairing and half and half.
Takayasu Sekihara (Osaka U., RCNP)🇯🇵 · Eulogio Oset (Valencia U. & Valencia U., IFIC)🇪🇸
We study the semileptonic decays of , , and mesons into the light scalar mesons [, , , and ] and the light vector mesons [, , , and ]. With the help of a chiral unitarity approach in coupled channels, we compute the branching fractions for scalar meson processes of the semileptonic decays in a simple way. Using current known values of the branching fractions, we make predictions for the branching fractions of the semileptonic decay modes with other scalar and vector mesons. Furthermore, we calculate the , , , and invariant mass distributions in the semileptonic decays of mesons, which will help us clarify the nature of the light scalar mesons.
Ryo Yoshiike🇯🇵 · Kazuya Nishiyama🇯🇵 · Tositaka Tatsumi🇯🇵
Considering the density wave of scalar and pseudoscalar condensates, we study the response of quark matter to a weak external magnetic field. In an external magnetic field, the energy spectrum of the lowest Landau level becomes asymmetric about zero, which is closely related to chiral anomaly, and gives rise to the spontaneous magnetization. This mechanism may be one of candidates for the origin of the strong magnetic field in pulsars and/or magnetars.
H. M. Mansour🇪🇬 · M. Abu-Shady🇪🇬
The linear sigma model at finite temperature and chemical potential is systematically studied using the coherent-pair approximation, in which fully taking quantum of fields are included. The expectation value of the chiral Hamiltonian density is minimized and the resulting equations for the nucleon are solved. The qualitative features of the quantized sigma and pion fields are strong sensitive to the change of temperature and baryonic chemical potential and are in agreement with the mean-field approximation calculations. It is noticed that the nucleon mass increases with increasing coherence parameter. In addition, the nucleon mass increases with increasing temperature and the baryonic chemical potential and then it decreases at higher values of the temperature and baryonic chemical potential. The obtained results show that the mean-square radius of the proton and the neutron increase with increasing temperature or the baryonic chemical potential and that the pion-nucleon coupling constant decreases with the temperature or chemical potential. We conclude that the coherent-pair approximation successfully give better description of the nucleon properties at finite temperature and baryonic chemical potential
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