Lattice QCD (QCDLAT)
In collaboration with Rome I and Madrid, we are studying neutral meson oscillations in the static limit. The renormalization and mixing properties of both Wilson-like and Ginsparg-Wilson light quarks have been analysed. This analysis is extended to the O(1/mb) operators contributing beyond the static approximation.
In the framework of the CLS effort, we are involved in a large scale PRACE simulation project for the generation of Nf=2+1 ensembles with pion masses approaching the physical point and open boundary conditions. Several quantities (decay constants, quark masses, meson spectroscopy ecc.) are studied both in the Wilson fermion and the twisted mass formalism; the latter are used for valence quarks in a mixed action setup.
The above computations require renormalization and O(a) improvement. This is carried out by the Alpha collaboration, of which Rome II is an active participant. We are applying Schroedinger Functional and Gradient Flow renormalization schemes for an accurate computation of the renormalization parameters and improvement coefficients of the quark masses, with particular emphasis to the control of the RG running over scales ranging from Lambda-QCD to M_W. Moreover, we apply new Schroedinger Functional Ward identities to the computation of the scale independent ratio of the renormalization parameters of the scalar and pseudoscalar densities.
Tor Vergata is actively participating in the Editorial Board of the FLAG collaboration, which reviews, among others, lattice results related to pion, kaon, D- and B-meson physics with the aim of making them easily accessible to the particle-physics community.