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

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.