Bc decays from highly improved staggered quarks and NRQCD
نویسندگان
چکیده
We calculate semileptonic form factors for the decays Bc→ ηc lν and Bc→ J/ψ lν over the entire q2 range, using a highly improved lattice quark action for charm at several lattice spacings down to a = 0.045 fm. We have two ways of treating the b quark: either with an O(αs) improved NRQCD formalism or by extrapolating a heavy mass mh to mb in the relativistic formalism. Comparison of the two approaches provides an important cross-check of methodologies in lattice QCD. Nonperturbative renormalisation of the currents in the relativistic theory also allows us then to fix NRQCD-charm normalisation for b to c decays such as B→ D and B→ D∗.
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