Couplings between pion and charmed mesons

Abstract

We compute the couplings $D{D}^{\ast }\pi$,$D_1{D}^{\ast }\pi$,$D^{\ast }{D}^{\ast }\pi$, $D_1{D}_1\pi$ using QCD sum rules. These couplings are important inputs in the meson exchange model calculations used to estimate the amount of $J/\psi$ absorption due to pions and rho mesons in heavy ion collisions. Our sum rules are constructed at the first order in the pion momentum $p_{\mu }$, which give the couplings that are not trivially related to the soft-pion theorem. Our calculated couplings, which somewhat depend upon the values of the heavy meson decay constants, are $g_{D{D}^{\ast }\pi }=8.2\pm 0.1$, $g_{D_1{D}^{\ast }\pi }=15.8\pm 2\mathrm{GeV}$, $g_{D^{\ast }{D}^{\ast }\pi }=0.3\pm 0.03$ and $g_{D_1{D}_1\pi }=0.17\pm 0.04$.

Comments: 16 pages including 4 postscript figures. To be published in European Physical Journal C