Rare FCNC radiative leptonic B_s,d → γ l⁺l⁻ decays in the SM

Autor(en)

Dmitri Melikhov, Anastasiia Kozachuk, Nikolai Nikitin

Abstrakt

We report our recent results [1] for long-distance QCD effects in the flavour-changing neutral current radiative leptonic decays B → γ ℓ⁺ ℓ⁻, ℓ = {e, µ }. One encounters here two distinct types of long-distance effects: those encoded in the B → γ transition form factors induced by the b → q quark currents, and those related to the charm-loop effects. We calculate the B → γ form factors in a broad range of the momentum transfers making use of the relativistic dispersion approach based on the constituent quark picture which has proven to provide reliable predictions for many weak-transition form factors. Concerning the description of the charm-loop contributions, we point out two observations: First, the precise description of the charmonium resonances, in particular, the relative phases between ψ and ψ ^′, has impact on the differential distributions and on the forward-backward asymmetry, A_FB, in a broad range of q² ≥ 5 GeV². Second, the shape of A_FB in B → γ ℓ⁺ ℓ⁻ and in B → V ℓ⁺ ℓ⁻ (V the vector meson) in the q²-region between ψ and ψ ^′ provides an unambiguous probe of the relative phases between ψ and ψ ^′. Fixing the latter will lead to a sizeable reduction of the theoretical uncertainties in A_FB at q² = 5 − 9 GeV² where it has the sensitivity to physics beyond the SM.

Organisation(en)

Teilchenphysik

Externe Organisation(en)

Österreichische Akademie der Wissenschaften (ÖAW), Lomonosov Moscow State University (MSU), A.I. Alikhanov Institute of Theoretical and Experimental Physics (ITEP)

Journal

Proceedings of Science (PoS)

Band

336

Anzahl der Seiten

8

DOI

https://doi.org/10.22323/1.336.0274

Publikationsdatum

2019

Peer-reviewed

Ja

ÖFOS 2012

103034 Teilchenphysik

ASJC Scopus Sachgebiete

General

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/rare-fcnc-radiative-leptonic-bsd---ll-decays-in-the-sm(764407f3-c767-4d39-aefd-35dec8e3f441).html