Dr Silvano Simula (INFN - Roma Tre)
Electromagnetic effects on the leptonic decay rates pi+ -> mu+ nu and K+ -> mu+ nu are evaluated for the first time on the lattice. Following a method recently proposed in Ref.  the emission of virtual photons at leading order in the e.m. coupling is evaluated on the lattice with the subtraction of the infrared divergence computed for a point-like meson at finite lattice volume. The physical decay rate is then obtained by adding the emission of real photons regularized with a photon mass. Using the gauge ensembles produced by ETMC with Nf=2+1+1 dynamical quarks the feasibility of the lattice approach is demonstrated and preliminary results for the decay rates of charged pion and kaon will be presented. . N. Carrasco et al., Phys. Rev. D91 (2015) 074506.
Prof. Vittorio Lubicz (University of Roma Tre)
Dr Cecilia Tarantino (University of Roma Tre) Prof. Christopher T. Sachrajda (University of Southampton) Dr Francesco Sanfilippo (University of Southampton) Prof. Guido Martinelli (University of Rome "La Sapienza") Dr Nazario Tantalo (University of Roma Tor Vergata) Dr Silvano Simula (INFN - Roma Tre)