Impact of background effects on the inclusive Vcb determination

Mannel, Thomas; Rahimi, Muslem; Vos, Kimberley

doi:10.1007/jhep09(2021)051

Cited by 9 publications

(9 citation statements)

References 36 publications

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“…Experimentally, in order to obtain the semileptonic B → X c , the B → X u background has to be dealt with. On the other hand, as pointed out in [14], this V 2 ub /V 2 cb suppressed contribution can also be calculated in the local OPE. Naively taking the B → X c rate and setting ρ → 0 works up to 1/m 2 b , but at order 1/m 3 b additional four-quark operators (weak annihilation) have to be introduced that cure the divergence arising in the ρ 3 D term (see e.g.…”

Section: Ratios For Semileptonic B → Xmentioning

confidence: 64%

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Standard Model predictions for lepton flavour universality ratios of inclusive semileptonic B decays

Rahimi

Vos

2022

J. High Energ. Phys.

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We present Standard Model predictions for lepton flavour universality ratios of inclusive B → X(c)$$ \ell {\overline{\nu}}_{\ell } $$ ℓ ν ¯ ℓ . For the ℓ = μ, e, these ratios are very close to unity as expected. For the τ mode, we update the SM prediction for the branching ratio including power-corrections in the heavy-quark expansion up to 1/$$ {m}_b^3 $$ m b 3 . These inclusive ratios serve as an important cross-check of the exclusive B → D(*)$$ \ell {\overline{\nu}}_{\ell } $$ ℓ ν ¯ ℓ modes, in which tensions exists between the predictions and measurements in those modes.

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Section: Ratios For Semileptonic B → Xmentioning

confidence: 64%

“…Here L µν is the lepton tensor and W µν the hadronic tensor as defined in e.g. [14]. Expressing the W µν tensor in Lorentz scalars as usual then gives…”

Section: Inclusive Decay Of B → C ν With Massive Leptonsmentioning

confidence: 99%

Standard Model predictions for lepton flavour universality ratios of inclusive semileptonic B decays

Rahimi

Vos

2022

J. High Energ. Phys.

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“…In addition, new branching ratio measurements with (different) q 2 thresholds would be the natural input for the RPI V cb determination. Further measurements of B → X ν would be highly desirable, such that they can be directly used in our analysis by implementing both the b → c and b → u in the local OPE [67]. This way uncertainties from subtracting the b → u contributions can be avoided, increasing the experimental precision.…”

Section: The B → X C ν Branching Fractionmentioning

confidence: 99%

First extraction of inclusive $V_{cb}$ from $q^2$ moments

Bernlochner¹,

Fael²,

Olschewsky³

et al. 2022

Preprint

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We present the first determination of V cb from inclusive B → X c ν using moments of the dilepton invariant mass, q 2 . These moments are reparametrization invariant quantities and depend on a reduced set of non-perturbative parameters. This reduced opens a new path to extract these parameters up to 1/m 4 b purely from data and thereby reducing the uncertainty on V cb . In this paper, we present our first determination of V cb using this method. Combining the recent measurements of q 2 moments by Belle and Belle II, our default fit gives |V cb | = (41.69 ± 0.63) • 10 −3 . This results presents an important independent cross check of, and is consistent with, the previous state-of-the-art inclusive determinations using lepton energy and hadronic invariant mass moments.

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“…Recently, it was suggested in Ref. [38] to instead measure observables in B → Xlν l decays and subtract the B → X u lν l component using HQE based predictions . Using the linearity of the numerator and denominator in Eq.…”

Section: Subtraction Of Thementioning

confidence: 99%

The forward-backward asymmetry and differences of partial moments in inclusive semileptonic B decays

Herren

2022

Preprint

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Global fits to moments of kinematic distributions measured in inclusive semileptonic B → X c lν l enable the determination of the Cabibbo-Kobayashi-Maskawa matrix element |V cb | together with non-perturbative matrix elements of the heavy quark expansion. In current fits, only two distinct kinematic distributions are employed and, as a consequence, higher moments of these distributions need to be taken into account to extract the relevant non-perturbative matrix elements. The moments of a given distribution are highly correlated and experimental uncertainties increase for higher moments. To address these issues, Turczyk suggested the inclusion of the charged lepton forward-backward asymmetry A F B in global fits, since it provides information on non-perturbative parameters beyond the commonly used moments.It is possible to construct differences of partial moments of kinematic distributions, which can provide additional information on the non-perturbative parameters beyond A F B and are studied in this work for the first time. Further, experimental cuts on the four-momentum transfer square are studied and are shown to preserve the shape of the angular distribution, in contrast to commonly used cuts on the lepton energy. Finally, the impact of final-state radiation and experimental lepton identification requirements on measurements of A F B and differences of partial moments are discussed.

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Impact of background effects on the inclusive Vcb determination

Cited by 9 publications

References 36 publications

Standard Model predictions for lepton flavour universality ratios of inclusive semileptonic B decays

Standard Model predictions for lepton flavour universality ratios of inclusive semileptonic B decays

First extraction of inclusive $V_{cb}$ from $q^2$ moments

The forward-backward asymmetry and differences of partial moments in inclusive semileptonic B decays

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