RI/MOM renormalization constants (N_f=4) and the strong coupling constant (N_f=2+1+1) from twisted-mass QCD

Abstract

We study RI/MOM renormalization constants of bilinear quark operators for $N_f=4$ and the strong coupling constant for $N_f=2+1+1$ using Wilson twisted-mass fermions. We use the "egalitarian" method to remove H(4) hypercubic artifacts non-perturbatively, which enables us to study physical quantities in a wide range of momenta. We then apply OPE in studying the running behavior of $Z_q$ and ${\alpha }_s$, from which we are able to extract the Landau gauge dimension-two gluon condensate $<A^2>$ which is of phenomenological interest.

Comments: 7 pages, talk presented at The XXIX International Symposium on Lattice Field Theory - Lattice 2011, July 10-16, 2011, Squaw Valley, Lake Tahoe, California