Extraction of the D ^{∗}Dπ coupling from D ^{∗} decays
Abstract
The decays D ^{∗} → Dπ and D ^{∗} → Dγ are well described by heavy meson chiral perturbation theory. With the recent measurement of B(D ^{∗+} → D ^{+}γ), the D ^{∗0}, D ^{∗+} and D _{s}^{∗} branching fractions can be used to extract the D ^{∗}Dπ and D ^{∗}Dγ couplings g and β. The D ^{∗} → Dγ decays receive important corrections at order √ m_{q} and, from the heavy quark magnetic moment, at order 1/ m_{c}. Here all the decay rates are computed to one loop, to first order in m_{q} and 1/ m_{c}, including the effect of heavy meson mass splittings, and the counterterms at order m_{q}. A fit to the experimental data gives two possible solutions, g = 0.27 _{0.020.02}^{+0.04+0.05}, β= 0.85 _{0.1  0.1}^{+0.2 + 0.3} GeV ^{} or g = 0.76 _{0.03 0.1}^{+0.03+0.2}, β = 4.90 _{0.30.7}^{+0.3+5.0} GeV ^{1}. The first errors are experimental, while the second are estimates of the uncertainty induced by the counterterms. (The experimental limit Γ _{D ∗+} < 0.13 MeV excludes the g = 0.76 solution.) Predictions for the D ^{∗} and B ^{∗} widths are given.
 Publication:

Nuclear Physics B
 Pub Date:
 September 1998
 DOI:
 10.1016/S05503213(98)003745
 arXiv:
 arXiv:hepph/9803227
 Bibcode:
 1998NuPhB.529...62S
 Keywords:

 High Energy Physics  Phenomenology
 EPrint:
 22 pages, 6 figs., minor typos corrected, comment on large Nc scaling of the counterterms added, to appear in Nucl.Phys.B