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Ratios of heavy hadron semileptonic decay rates

High Energy Physics - Phenomenology 2011-03-23 v2

Abstract

Ratios of charmed meson and baryon semileptonic decay rates appear to be satisfactorily described by considering only the lowest-lying (S-wave) hadronic final states and assuming the kinematic factor describing phase space suppression is the same as that for free quarks. For example, the rate for DsD_s semileptonic decay is known to be (17.0±5.3)(17.0 \pm 5.3)% lower than those for D0D^0 or D+D^+, and the model accounts for this difference. When applied to hadrons containing bb quarks, this method implies that the BsB_s semileptonic decay rate is about 1% higher than that of the nonstrange BB mesons. This small difference thus suggests surprisingly good local quark-hadron duality for BB semileptonic decays, complementing the expectation based on inclusive quark-hadron duality that these differences in rates should not exceed a few tenths of a percent. For Λb\Lambda_b semileptonic decay, however, the inclusive rate is predicted to be about 13% greater than that of the nonstrange BB mesons. This value, representing a considerable departure from a calculation using a heavy quark expansion, is close to the corresponding experimental ratio Γ(Λb)/Γˉ(B)=1.13±0.03\Gamma(\Lambda_b)/ \bar \Gamma(B) = 1.13 \pm 0.03 of total decay rates.

Keywords

Cite

@article{arxiv.1012.5098,
  title  = {Ratios of heavy hadron semileptonic decay rates},
  author = {Michael Gronau and Jonathan L. Rosner},
  journal= {arXiv preprint arXiv:1012.5098},
  year   = {2011}
}

Comments

12 pages, no figures. References added