In:
Journal of High Energy Physics, Springer Science and Business Media LLC, Vol. 2023, No. 4 ( 2023-04-24)
Kurzfassung:
We present a strategy for calculating the rare decay of a Σ + ( uus ) baryon to a proton ( uud ) and di-lepton pair using lattice QCD. To determine this observable one needs to numerically evaluate baryonic two-, three-, and four-point correlation functions related to the target process. In particular, the four-point function arises from the insertion of incoming and outgoing baryons, together with a weak Hamiltonian mediating the s → d transition and an electromagnetic current creating the outgoing leptons. As is described in previous work in other contexts, this four-point function has a highly non-trivial relation to the physical observable, due to proton and proton-pion intermediate states. These lead to growing Euclidean time dependence and, in the case of the two-particle intermediate states, to power-like volume effects. We discuss how to treat these issues in the context of the Σ + → pℓ + ℓ − decay and, in particular, detail the relation between the finite-volume estimator and the physical, complex-valued amplitude. In doing so, we also make connections between various approaches already described in the literature.
Materialart:
Online-Ressource
ISSN:
1029-8479
DOI:
10.1007/JHEP04(2023)108
Sprache:
Englisch
Verlag:
Springer Science and Business Media LLC
Publikationsdatum:
2023
ZDB Id:
2027350-2
Permalink