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Abstract / Description of output
We present a strategy for calculating the rare decay of a Σ+(uus) baryon to a proton (uud) and dilepton pair using lattice QCD. To determine this observable one needs to numerically evaluate baryonic two, three, and fourpoint correlation functions related to the target process. In particular, the fourpoint 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 fourpoint function has a highly nontrivial relation to the physical observable, due to proton and protonpion intermediate states. These lead to growing Euclidean time dependence and, in the case of the twoparticle intermediate states, to powerlike 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 finitevolume estimator and the physical, complexvalued amplitude. In doing so, we also make connections between various approaches already described in the literature.
Original language  English 

Article number  108 
Pages (fromto)  138 
Number of pages  38 
Journal  Journal of High Energy Physics 
Volume  2023 
Issue number  4 
DOIs  
Publication status  Published  24 Apr 2023 
Keywords / Materials (for Nontextual outputs)
 Algorithms and theoretical Developments
 Hadronic Matrix Elements
 Weak Decays
 Lattice QCD
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European network for Particle physics, Lattice field theory and Extreme computing
1/01/19 → 30/09/23
Project: Research
