SU(3) symmetry breaking in decay constants and electromagnetic properties of pseudoscalar heavy mesons

TL;DR

This paper investigates SU(3) symmetry breaking effects on decay constants and radii of pseudoscalar heavy mesons using light-front framework, providing specific ratios and insights into quark mass dependencies.

Contribution

It introduces a method to estimate decay constant ratios and radii of heavy mesons considering SU(3) symmetry breaking, with results largely independent of heavy quark masses.

Findings

Estimated $f_{D_s}/f_D=1.29\u00b10.07$ and $f_{B_s}/f_B=1.32\u00b10.08$.

Calculated mean square radii: rom 0.690 to 0.790 for $D_s^+$ and $D^+$, and from 0.662 to 0.769 for $B_s^0$ and $B^0$.

Abstract

In this paper, the decay constants and mean square radii of pseudoscalar heavy mesons are studied in the SU(3) symmetry breaking. Within the light-front framework, the ratios $f_{D_s}/f_D$ and $f_{B_s}/f_B$ are individually estimated using the hyperfine splittings in the $D_{(s)}^*-D_{(s)}$ and $B_{(s)}^*-B_{(s)}$ states and the light quark masses, $m_{s,q}$ ($q=u,d$), to extract the wave function parameter $\beta$. The values $f_{D_s}/f_D= 1.29\pm0.07$ and $f_{B_s}/f_B= 1.32\pm 0.08$ are obtained, which are not only chiefly determined by the ratio of light quark masses $m_s/m_q$, but also insensitive to the heavy quark masses $m_{c,b}$ and the decay constants $f_{D,B}$. The dependence of $f_{B_c}/f_B$ on $\Delta M_{B_cB^*_c}$ with the varied charm quark masses is also shown. In addition, the mean square radii are estimated as well. The values $\sqrt{<r^2_{D_s^+}><r^2_{D^+}>} =0.740^{-0.041}_{+0.050}$ and $\sqrt{<r^2_{B_s^0}><r^2_{B^0}>} =0.711^{-0.049}_{+0.058}$ are obtained, and the sensitivities of $<r^2_P >$ on the heavy and light quark masses are similar to those of the decay constants.