0000000000143623
AUTHOR
Juergen G. Körner
J/ψ dissociation cross sections in a relativistic quark model
We calculate the amplitudes and the cross sections of the charm dissociation processes J/\psi \pi => D \bar D, D* \bar D, D \bar D*, D* \bar D* within a relativistic constituent quark model. We consistently account for the contributions coming from both the box and triangle diagrams that contribute to the dissociation processes. The cross section is dominated by the D* \bar D and D* \bar D* channels. When summing up the four channels we find a maximum total cross section of about 2.3 mb at sqrt(s) \approx 4.1 GeV. We compare our results to the results of other model calculations.
Semileptonic decays ofBcmesons into charmonium states in a relativistic quark model
We use the framework of a relativistic constituent quark model to study the semileptonic transitions of the ${B}_{c}$ meson into $(\overline{c}c)$ charmonium states where $(\overline{c}c)={\ensuremath{\eta}}_{c}(^{1}S_{0})$, $J/\ensuremath{\psi}(^{3}S_{1})$, ${\ensuremath{\chi}}_{c0}(^{3}P_{0})$, ${\ensuremath{\chi}}_{c1}(^{3}P_{1})$, ${h}_{c}(^{1}P_{1})$, ${\ensuremath{\chi}}_{c2}(^{3}P_{2})$, $\ensuremath{\psi}(^{3}D_{2})$. We compute the ${q}^{2}$ dependence of all relevant form factors and give predictions for their semileptonic ${B}_{c}$ decay modes including also their $\ensuremath{\tau}$ modes. We derive a formula for the polar angle distribution of the charged lepton in the $(l{\ens…
Exclusive/inclusive ratio of semileptonicΛbdecays
We present theoretical evidence that the exclusive/inclusive ratio of semileptonic ${\ensuremath{\Lambda}}_{b}$ decays exceeds that of semileptonic B decays where the experimental exclusive/inclusive ratio amounts to about 66%. We start from the observation that the spectator quark model provides a lower bound on the leading order Isgur-Wise function of the ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}{\ensuremath{\Lambda}}_{c}$ transition in terms of the corresponding $\stackrel{\ensuremath{\rightarrow}}{B}{D,D}^{*}$ mesonic Isgur-Wise function. Using experimental data for the $\stackrel{\ensuremath{\rightarrow}}{B}{D,D}^{*}$ mesonic Isgur-Wise functions this bound is established. Ap…