Friday, July 6, 2012

1207.1287 (V. Bertone et al.)

Kaon Mixing Beyond the SM from Nf=2 tmQCD and model independent
constraints from the UTA
   [PDF]

V. Bertone, N. Carrasco, M. Ciuchini, P. Dimopoulos, R. Frezzotti, V. Gimenez, V. Lubicz, G. Martinelli, F. Mescia, M. Papinutto, G. C. Rossi, L. Silvestrini, S. Simula, C. Tarantino, A. Vladikas
We present the first unquenched lattice QCD results for the matrix elements of the operators describing neutral kaon oscillations in extensions of the Standard Model. Owing to the accuracy of our calculation on \Delta S=2 weak Hamiltonian matrix elements, we are able to provide a refined Unitarity Triangle analysis improving the bounds coming from model independent constraints on New Physics. In our non-perturbative computation we use a combination of Nf=2 maximally twisted sea quarks and Osterwalder-Seiler valence quarks in order to achieve both O(a)-improvement and continuum-like renormalization properties for the relevant four-fermion operators. The calculation of the renormalization constants has been performed non-perturbatively in the RI-MOM scheme. Based on simulations at three values of the lattice spacing and a number of quark masses we have extrapolated/interpolated our results to the continuum limit and physical light/strange quark masses.
View original: http://arxiv.org/abs/1207.1287

No comments:

Post a Comment