Pion properties at finite nuclear density based on in-medium chiral perturbation theory

作者：Goda Soichiro^*; Jido Daisuke

来源：Progress of Theoretical and Experimental Physics, 2014, 2014(3): 033D03.

DOI：10.1093/ptep/ptu023

The in-medium pion properties, i. e. the temporal pion decay constant ft, the pion mass m(pi)(*), and the wave function renormalization in symmetric nuclear matter are calculated in an in-medium chiral perturbation theory up to the next-to-leading order of the density expansion O(k(F)(4)). The chiral Lagrangian for the pion-nucleon interaction is determined in vacuum, and the low-energy constants are fixed by experimental observables. We carefully define the in-medium state of the pion and find that the pionwave function renormalization plays an essential role in the in-medium pion properties. We show that the linear density correction is dominant and the next-to-leading corrections are not so large at the saturation density, while their contributions can be significant at higher densities. The main contribution of the next-to-leading order comes from the double scattering term. We also discuss whether the low-energy theorems, the Gell-Mann-Oakes-Renner relation and the Glashow-Weinberg relation, are satisfied in the nuclear medium beyond the linear density approximation. We also find that the wave function renormalization is enhanced as much as 50% at the saturation density including the next-to-leading contribution, and that the wave function renormalization can be measured in the in-medium pi(0) -> gamma gamma decay.

• 出版日期2014-3