Nucleon axial coupling from Lattice QCD

Chia Cheng Chang, Amy Nicholson, Enrico Rinaldi, Evan Berkowitz, Nicolas Garron, David Brantley, Henry Monge-Camacho, Chris Monahan, Chris Bouchard, M.A. Clark, Balint Joo, Thorsten Kurth, Kostas Orginos, Pavlos Vranas, Andre Walker-Loud

Mar 2018

Abstract

We present state-of-the-art results from a lattice QCD calculation of the nucleon axial coupling, $g_{A}$ , using M $" o b i u s D o m a i n - W a l l f e r m i o n s s o l v e d o n t h e d y n a m i c a l $ N_{f} = 2 + 1 + 1 $ H I S Q e n s e m b l e s a f t e r t h e y a r e s m e a r e d u s i n g t h e g r a d i e n t - f l o w a l g o r i t h m . R e l e v a n t t h r e e - p o i n t c o r r e l a t i o n f u n c t i o n s a r e c a l c u l a t e d u s i n g a m e t h o d i n s p i r e d b y t h e F e y n m a n - H e l l m a n n t h e o r e m, a n d d e m o n s t r a t e s i g n i f i c a n t i m p r o v e m e n t i n s i g n a l f o r f i x e d s t o c h a s t i c s a m p l e s . T h e c a l c u l a t i o n i s p e r f o r m e d a t f i v e p i o n m a s s e s o f $ m_{π} \sim \4 00, 350, 310, 220, 130 $ ̃ M e V, t h r e e l a t t i c e s p a c i n g s o f $ a \sim \0 .15, 0.12, 0.09 $ ̃ f m, a n d w e d o a d e d i c a t e d v o l u m e s t u d y w i t h $ m_{π} L \sim \3 .22, 4.29, 5.36 $ . C o n t r o l o v e r a l l r e l e v a n t s o u r c e s o f s y s t e m a t i c u n c e r t a i n t y a r e d e m o n s t r a t e d a n d q u a n t i f i e d . W e a c h i e v e a p r e l i m i n a r y v a l u e o f $ g_{A} = 1.285 (17) $, w i t h a r e l a t i v e u n c e r t a i n t y o f 1.33$ %.

Type

Journal article

Publication

EPJ Web of Conferences

Nucleon axial coupling from Lattice QCD

Abstract

Enrico Rinaldi

Research Scientist