Jul 26 – 30, 2021
US/Eastern timezone

Non-Perturbative Bounds for Semileptonic Decays in Lattice QCD

Jul 29, 2021, 2:45 PM
15m
Oral presentation Standard Model Parameters Standard Model Parameters

Speaker

Manuel Naviglio (INFN - National Institute for Nuclear Physics, Dipartimento di Fisica dell’Università di Pisa)

Description

We present a new method aiming at a non-perturbative, model-independent determination of the momentum dependence of the form factors entering hadronic semileptonic decays using unitarity and analyticity constraints. We extend the original proposal of Ref. [1] and, using suitable two-point functions computed non-perturbatively, we determine the form factors at low-momentum transfer $q^2$ from those computed explicitly on the lattice at large $q^2$, without making any assumption about their $q^2$ dependence. As a training ground we apply the new method to the analysis of the lattice data of the semileptonic $D \to K \ell \nu_\ell$ decays obtained in Ref. [2] both at finite values of the lattice spacing and at the physical pion point in the continuum limit. We show that, starting from a limited set of data at large $q^2$ it is possible to determine quite precisely the form factors in a model independent way in the full kinematical range, obtaining a remarkable agreement with the direct calculation of the form factors of Ref. [2]. This finding opens the possibility to obtain non-perturbatively the form factors entering the semileptonic $B$ decays in their full kinematical range.

References

[1] L. Lellouch, Nucl. Phys. B 479(1996), 353-391 doi:10.1016/0550-3213(96)00443-9 [arXiv:hep-ph/9509358 [hep-ph]]
[2] V. Lubicz et al. [ETM],Phys. Rev. D 96 (2017) no.5, 054514 [erratum: Phys. Rev. D 99 (2019) no.9, 099902; erratum: Phys. Rev. D 100 (2019) no.7, 079901] doi:10.1103/PhysRevD.96.054514 [arXiv:1706.03017 [hep-lat]].

Primary authors

Dr Matteo Di Carlo (University of Edinburgh) Guido Martinelli (Sapienza Universita e INFN, Roma I (IT)) Manuel Naviglio (INFN - National Institute for Nuclear Physics, Dipartimento di Fisica dell’Università di Pisa) Dr Francesco Sanfilippo (INFN - Sezione di Roma Tre) Dr Silvano Simula (INFN - Sezione di Roma Tre) Ludovico Vittorio (SNS, Pisa)

Presentation materials