nucl-th digest · Jun 29, 2015

Heavy quarkonia in strong magnetic fields

We investigate the influence of a homogeneus and constant strong external magnetic field on the heavy-meson spectrum. Quarkonium states

c c ˉ

and

b b ˉ

are described within a non-relativistic framework and by means of a suitable potential model based on the Cornell parametrization. In particular, in this work we propose a model which takes into account the possible anisotropies emerging at the level of the static quark-antiquark potential, as observed in recent lattice studies. The investigation is perfomed both with and without taking into account the anisotropy of the static potential, in order to better clarify its effects

Comments:: 10 pages, 9 figures, 3 tables, minor changes, references added
Subjects:: High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:: 1506.07890 [pdf]

PRD(2015)·98 citations

[Submitted on 26 Jun 2015] (cross-list from hep-ph)

Extended Goldberger-Treiman relation obtained in a three-flavor parity doublet model

Hiroki Nishihara🇯🇵 · Masayasu Harada🇯🇵

We study masses and decay widths of positive and negative parity nucleons using a three-flavor parity doublet model, in which we introduce three representations, $[(3, 3 ˉ) \oplus (3 ˉ, 3)]$ , $[(3, 6) \oplus (6, 3)]$ , and $[(8, 1) \oplus (1, 8)]$ of the chiral U $(3)_{L} \times$ U $(3)_{R}$ symmetry. We find an extended version of the Goldberger-Treiman relation among the mass differences and the coupling constants for pionic transitions. This relation leads to an upper bound for the decay width of $N (1440) \to N (939) + π$ independently of the model parameters. We perform the numerical fitting of the model parameters and derive several predictions, which can be tested in future experiments or lattice QCD analysis. Furthermore, when we use the axial coupling of the excited nucleons obtained from lattice QCD analyses as inputs, we find that the ground state nucleon $N (939)$ consists of about 80% of $[(3, 6) \oplus (6, 3)]$ component, and that the chiral invariant mass of $N (939)$ is roughly $500$ -- $800$ MeV.

Comments:: 10 pages, 6 figures and 8 tables, version accepted for publication in Physical Review D
Subjects:: High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:: 1506.07956 [pdf]

PRD(2015)·28 citations

Monday·June 29, 2015

Heavy quarkonia in strong magnetic fields

Extended Goldberger-Treiman relation obtained in a three-flavor parity doublet model

Affiliations