Connected and disconnected contributions to nucleon axial form factors using N_f = 2 twisted mass fermions at the physical point

¹ Department of Physics, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
² Computation-based Science and Technology Research Center, The Cyprus Institute, 20 Kavafi Str., Nicosia 2121, Cyprus
³ Temple University,1925 N. 12th Street, Philadelphia, PA 19122-1801, USA
⁴ NIC, DESY, Platanenallee 6, D-15738 Zeuthen, Germany
⁵ Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA

^* Speaker, e-mail: k.hadjiyiannakou@cyi.ac.cy

Published online: 26 March 2018

Abstract

We present results on the isovector and isoscalar nucleon axial form factors including disconnected contributions, using an ensemble of N_f = 2 twisted mass cloverimproved Wilson fermions simulated with approximately the physical value of the pion mass. The light disconnected quark loops are computed using exact deflation, while the strange and the charm quark loops are evaluated using the truncated solver method. Techniques such as the summation and the two-state fits have been employed to access ground-state dominance.