45 research outputs found
Form factors and branching ratio for the B -> l nu gamma decay
Form factors parameterizing radiative leptonic decays of heavy mesons for photon energy are computed in the language
of dispersion relation. The contributing states to the absorptive part in the
dispersion relation are the multiparticle continum, estimated by quark triangle
graph and resonances with quantum numbers and which includes
and and thier radial excitations, which model the higher
state contributions. Constraints provided by the asymptotic behavior of the
structure dependent amplitude, Ward Identities and gauge invariance are used to
provide useful information for parameters needed. The couplings
and are predicted if we restrict to
first radial excitation; otherwise using these as an input the radiative decay
coupling constants for radial excitations are predicted. The value of the
branching ratio for the process is found to
be in the range . A detailed comparison is given with other
approaches.Comment: 22 pages+two ps figures; Paper has been throughly revised and Sudakov
resummation has been discussed; published versio
Frações de fósforo após extrações sucessivas com resina e incubação, em Latossolos e Luvissolos do semi-árido de Pernambuco
MIBiG 3.0: a community-driven effort to annotate experimentally validated biosynthetic gene clusters
Microbial Biotechnolog
Study of the plasma plume generated during near IR femtosecond laser irradiation of silicon targets
Apolipoprotein(a): Structure-Function Relationship at the Lysine-Binding Site and Plasminogen Activator Cleavage Site
Plastic deformation in nonstoichiometric UO2+x single crystals—I. Deformation at low temperatures
Measurement of hadron and lepton-pair production at 130 GeV<root s<140 GeV at LEP
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