Abstract:
Weextend the factorization formalism for a somewhat complex process W+ → B+ℓ+ℓ−
in the non-zero limit of invariant squared-mass of dilepton, q2, at the lowest order in
1/mb up to O(αs), inspired by the investigation of heavy-light meson production within
the context of heavy quark effective theory (HQET) factorization. In current study, we
have extended the HQET factorization formula for the decay W+ → B+ℓ+ℓ− and cal
culated the form factors up to next-to-leading order (NLO) corrections in αs. We have
shown that the amplitude of decay W+ → B+ℓ+ℓ− can be written into a convolution
between the perturbatively calculable hard-scattering kernel and the non-perturbative
light-cone distribution amplitude (LCDA) defined in HQET. The validity of HQET fac
torization depends on the assumed scale hierarchy mW ∼ mb ≫ ΛQCD. We calculated
the form factors associated to W+ → B+ℓ+ℓ− process in HQET factorization,revealing
details on its phenomenology. Furthermore, we conduct an exploratory phenomenolog
ical investigation on W+ → B+ℓ+ℓ− by using the LCDAs with an exponential model
for B+ meson. According to our research, the branching ratio for W+ → B+ℓ+ℓ− is
below 10−10. This channel in high luminosity LHC experiments may serve to further
restrict the value of λB even when the branching ratios are small.
