Physics Letters B (Mar 2017)

Consistency between SU(3) and SU(2) covariant baryon chiral perturbation theory for the nucleon mass

  • Xiu-Lei Ren,
  • L. Alvarez-Ruso,
  • Li-Sheng Geng,
  • Tim Ledwig,
  • Jie Meng,
  • M.J. Vicente Vacas

DOI
https://doi.org/10.1016/j.physletb.2017.01.024
Journal volume & issue
Vol. 766, no. C
pp. 325 – 333

Abstract

Read online

Treating the strange quark mass as a heavy scale compared to the light quark mass, we perform a matching of the nucleon mass in the SU(3) sector to the two-flavor case in covariant baryon chiral perturbation theory. The validity of the 19 low-energy constants appearing in the octet baryon masses up to next-to-next-to-next-to-leading order [1] is supported by comparing the effective parameters (the combinations of the 19 couplings) with the corresponding low-energy constants in the SU(2) sector [2]. In addition, it is shown that the dependence of the effective parameters and the pion-nucleon sigma term on the strange quark mass is relatively weak around its physical value, thus providing support to the assumption made in Ref. [2] that the SU(2) baryon chiral perturbation theory can be applied to study nf=2+1 lattice QCD simulations as long as the strange quark mass is close to its physical value.

Keywords