0000000000281111
AUTHOR
Zhomart Tyulemissov
Ab initio three-loop calculation of the W -exchange contribution to nonleptonic decays of double charm baryons
We have made an ab initio three-loop quark model calculation of the $W$-exchange contribution to the nonleptonic two-body decays of the doubly charmed baryons $\Xi_{cc}^{++}$ and $\Omega_{cc}^{+}$. The $W$-exchange contributions appear in addition to the factorizable tree graph contributions and are not suppressed in general. We make use of the covariant confined quark model previously developed by us to calculate the tree graph as well as the $W$-exchange contribution. We calculate helicity amplitudes and quantitatively compare the tree graph and $W$-exchange contributions. Finally, we compare the calculated decay widths with those from other theoretical approaches when they are available.
Analysis of the semileptonic and nonleptonic two-body decays of the double heavy charm baryon states Ξcc++,Ξcc+ and Ωcc+
We calculate the semileptonic and a subclass of sixteen nonleptonic two-body decays of the double charm baryon ground states Ξcc++,Ξcc+ and Ωcc+ where we concentrate on the nonleptonic decay modes. We identify those nonleptonic decay channels in which the decay proceeds solely via the factorizing contribution precluding a contamination from W exchange. We use the covariant confined quark model previously developed by us to calculate the various helicity amplitudes which describe the dynamics of the 1/2+→1/2+ and 1/2+→3/2+ transitions induced by the Cabibbo-favored effective (c→s) and (d→u) currents. We then proceed to calculate the rates of the decays as well as polarization effects and ang…
Analysis of the nonleptonic two-body decays of the Λ hyperon
We systematically study two-body nonleptonic decays of light lambda hyperon $\Lambda \to p \pi^- (n\pi^0)$ with account for both short- and long-distance effects. The short-distance effects are induced by five topologies of external and internal weak $W^\pm$ exchange, while long-distance effects are saturated by an inclusion of the so-called pole diagrams with intermediate $\frac{1}{2}^+$ and $\frac{1}{2}^-$ baryon resonances. The contributions from $\frac12^+$ resonances are calculated straightforwardly by account for nucleon and $\Sigma$ baryons whereas the contributions from $\frac{1}{2}^-$ resonances are calculated by using the well-known soft-pion theorem in the current-algebra approac…