{ "id": "hep-ph/9604208", "version": "v3", "published": "1996-04-01T19:34:15.000Z", "updated": "1996-06-26T13:59:30.000Z", "title": "Charm and Bottom Semileptonic Decays", "authors": [ "Patrick J. O'Donnell", "Gursevil Turan" ], "comment": "Latex, 19 pages, two figures are attached, a minor change in the manuscript related to this", "journal": "Phys.Rev.D56:295-302,1997", "doi": "10.1103/PhysRevD.56.295", "categories": [ "hep-ph" ], "abstract": "We review the present status of theoretical attempts to calculate the semileptonic charm and bottom decays and then present a calculation of these decays in the light--front frame at the kinematic point $q^2=0$. This allows us to evaluate the form factors at the same value of $q^2$, even though the allowed kinematic ranges for charm and bottom decays are very different. Also, at this kinematic point the decay is given in terms of only one form factor $A_{0}(0)$. For the ratio of the decay rates given by the E653 collaboration we show that the determination of the ratio of the Cabibbo--Kobayashi--Maskawa (CKM) matrix elements is consistent with that obtained from the unitarity constraint. At present, though, the unitarity method still has greater accuracy. Since comparisons of the semileptonic decays into $\\rho$ and either electrons or muons will be available soon from the E791 Fermilab experiment, we also look at the massive muon case. We show that for a range of $q^2$ the $SU(3)_F$ symmetry breaking is small even though the contributions of the various helicity amplitudes becomes more complicated. For $B$ decays, the decay $B \\rightarrow K^{*} \\ell \\bar{\\ell}$ at $q^2=0$ involves an extra form factor coming from the photon contribution and so is not amenable to the same kind of analysis, leaving only the decay $B \\rightarrow K^{*}\\nu \\bar{\\nu}$ as a possibility. As the mass of the decaying particle increases we note that the $SU(3)$ symmetry becomes badly broken at $q^2=0$.", "revisions": [ { "version": "v3", "updated": "1996-06-26T13:59:30.000Z" } ], "analyses": { "subjects": [ "13.20.He", "13.20.Fc", "12.39.Ki" ], "keywords": [ "semileptonic decays", "kinematic point", "e791 fermilab experiment", "decaying particle increases", "helicity amplitudes" ], "tags": [ "journal article" ], "publication": { "publisher": "APS", "journal": "Phys. Rev. D" }, "note": { "typesetting": "LaTeX", "pages": 19, "language": "en", "license": "arXiv", "status": "editable", "inspire": 417284 } } }