Chiral corrections to the f_V^T/f_V ratio for vector mesons

TL;DR

This paper calculates the leading chiral corrections to the ratio of tensor to vector decay couplings in vector mesons, revealing that only the rho meson is affected by pion logarithms, with results supported by lattice data.

Contribution

It provides a theoretical calculation of chiral corrections to the f_V^T/f_V ratio for vector mesons, highlighting the role of chiral symmetry and flavor structure, and extends to all orders in strange quark mass expansion.

Findings

Leading chiral logarithms are fixed by chiral symmetry from tadpole contributions.

Only the rho meson is sensitive to pion logarithms among the vector mesons.

Lattice data are consistent with the theoretical predictions.

Abstract

In this letter we compute the leading chiral corrections to the ratio between the tensor and the vector decay couplings for the lowest lying vector meson multiplet (rho, K^*, phi). We show that the leading chiral logarithms arise from tadpole contributions and are therefore entirely fixed by chiral symmetry, while the next to leading corrections are purely analytic. Interestingly, the flavour structure of the chiral logarithms implies that only the rho meson is sensitive to pion logarithms. By examining SU(2)_L\times SU(2)_R\times U(1)_S theories we show that this result can be easily understood and that it holds to all orders in the m_s expansion. Recent lattice data seem to comply with our results.