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

Leljak, Domagoj; Melić, Blaženka; van Dyk, Danny (2021) The overline{B} → π form factors from QCD and their impact on |Vub|. Journal of High Energy Physics, 2021 (7). ISSN 1126-6708

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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.

Item Type: Article
Uncontrolled Keywords: flavour physics ; weak quark transitions ; CKM matrix ; Vub ; qcd ; form factors ; sum rules
Subjects: NATURAL SCIENCES > Physics
NATURAL SCIENCES > Physics > Physics of Elementary Particles and Fields
Divisions: Theoretical Physics Division
Project titleProject leaderProject codeProject type
Raspadi i vremena života teških hadronaMelić, BlaženkaIP-2019-04-7094HRZZ
Sinergijom do uspjeha: RBI-T-WINNING i ESIF udruženi u jačanju izvrsnosti Zavoda za teorijsku fiziku Instituta Ruđer BoškovićMelic, BlazenkaKK.
Depositing User: Domagoj Leljak
Date Deposited: 03 Aug 2021 09:46
DOI: 10.1007/jhep07(2021)036

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