Speaker
Prof.
Guido Martinelli
(Universita' di Roma "La Sapienza" and Cern)
Description
We investigate the topological properties of $N_f = 2 + 1$ QCD with
physical quark masses, both at zero and finite temperature. At zero
temperature both finite size and finite cut-off effects have been
studied by comparing the continuum extrapolated results for the
topological susceptibility $\chi$ with the predictions from chiral
perturbation theory. At finite temperature, we explore a region going
from $T_c$ up to around $4T_c$, where continuum extrapolated results for the
topological susceptibility and for the fourth moment of the topological
charge distribution are obtained. While the fourth moment converges to
the dilute instanton gas prediction the topological susceptibility
differs strongly both in the size and in the temperature dependence.
This results in a shift of the axion dark matter window of almost one
order of magnitude with respect to the instanton computation.
Primary author
Prof.
Guido Martinelli
(Universita' di Roma "La Sapienza" and Cern)
Co-authors
Dr
Claudio Bonati
(Università di Pisa)
Mr
Francesco Sanfilippo
(University of Southampton)
Prof.
Giovanni Villadoro
(ICTP)
Massimo D'Elia
(University of Pisa and INFN)
Mr
Michele Mesiti
(University of Pisa and INFN - Sezione di Pisa)
