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SUMMARY:D. Giusti - Methods for high-precision determinations of radiative
 -leptonic decay form factors using lattice QCD
DTSTART:20230703T141500Z
DTEND:20230703T151500Z
DTSTAMP:20260827T235300Z
UID:indico-event-364@indico.hiskp.uni-bonn.de
DESCRIPTION:In the region of hard photon energies\, radiative leptonic dec
 ays represent important probes of the internal structure of hadrons. Moreo
 ver\, radiative decays can provide independent determinations of Cabibbo-K
 obayashi-Maskawa matrix elements with respect to purely leptonic or semile
 ptonic channels. Prospects for a precise determination of leptonic decay r
 ates with emission of a hard photon are particularly interesting\, especia
 lly for the decays of heavy mesons for which currently only model-dependen
 t predictions\, based on QCD factorization and sum rules\, are available t
 o compare with existing experimental data.We present a study of lattice-QC
 D methods to determine the relevant hadronic form factors for radiative le
 ptonic decays of pseudoscalar mesons and provide numerical results for $D_
 s^{+} \\to \\ell^{+} \\nu_\\ell \\gamma$ using a domain-wall action for al
 l quark flavors. We show how to best control two sources of systematic err
 or inherent in the calculation\, specifically the unwanted excited states 
 created by the meson interpolating field\, and unwanted exponentials in th
 e sum over intermediate states.With moderate statistics\, thanks to the us
 e of an infinite-volume approximation method and improved estimators\, we 
 are able to provide rather precise\, first-principles results for the stru
 cture-dependent vector and axial form factors in the full kinematical (pho
 ton-energy) range. Our preliminary continuum-extrapolated lattice determin
 ations may then be employed to compute the differential decay rate and the
  corresponding branching fraction and make comparisons with existing exper
 imental data.\n\nhttps://indico.hiskp.uni-bonn.de/event/364/
LOCATION:Nußallee 14-16/3.013 (HISKP) - Seminar Room II (HISKP)
URL:https://indico.hiskp.uni-bonn.de/event/364/
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