Naslov
The overline{;;;B};;; → π form factors from QCD and their impact on |Vub|

Autori
Leljak, Domagoj ; Melić, Blaženka ; van Dyk, Danny

Izvornik
Journal of High Energy Physics (1126-6708) 2021 (2021), 7; 036, 34

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
flavour physics ; weak quark transitions ; CKM matrix ; Vub ; qcd ; form factors ; sum rules

Sažetak
We revisit light-cone sum rules with pion distribution amplitudes to determine the full set of local B→π form factors. To this end, we determine all duality threshold parameters from a Bayesian fit for the first time. Our results, obtained at small momentum transfer q2, are extrapolated to large q2 where they agree with precise lattice QCD results. We find that a modification to the commonly used BCL parametrization is crucial to interpolate the scalar form factor between the two q2 regions. We provide numerical results for the form factor parameters -- including their covariance -- based on simultaneous fit of all three form factors to both the sum rule and lattice QCD results. Our predictions for the form factors agree well with measurements of the q2 spectrum of the semileptonic decay B¯0→π+ℓ−ν¯. From the world average of the latter we obtain |Vub|= (3.77±0.15)⋅10−3, which is in agreement with the most recent inclusive determination at the 1σ level.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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