Nucleon scalar and tensor charges using lattice QCD simulations at the physical value of the pION mass
Date
2017Author
Alexandrou, ConstantiaConstantinou, Martha
Dimopoulos, Petros
Frezzotti, R.
Hadjiyiannakou, Kyriakos
Jansen, K.
Kallidonis, Christos
Kostrzewa, B.
Koutsou, Giannis
Mangin-Brinet, M.
Vaquero Avilès-Casco, A.
Wenger, U.
ISSN
2470-0010Source
Physical Review DVolume
95Issue
11Google Scholar check
Metadata
Show full item recordAbstract
We present results on the light, strange and charm nucleon scalar and tensor charges from lattice QCD, using simulations with Nf=2 flavors of twisted mass clover-improved fermions with a physical value of the pION mass. Both connected and disconnected contributions are included, enabling us to extract the isoscalar, strange and charm charges for the first time directly at the physical point. Furthermore, the renormalization is computed nonperturbatively for both isovector and isoscalar quantities. We investigate excited state effects by analyzing several sink-source time separations and by employing a set of methods to probe ground state dominance. Our final results for the scalar charges are gSu=5.20(42)(15)(12), gSd=4.27(26)(15)(12), gSs=0.33(7)(1)(4), and gSc=0.062(13)(3)(5) and for the tensor charges gTu=0.794(16)(2)(13), gTd=-0.210(10)(2)(13), gTs=0.00032(24)(0), and gTc=0.00062(85)(0) in the MS scheme at 2 GeV. The first error is statistical, the second is the systematic error due to the renormalization and the third the systematic arising from estimating the contamination due to the excited states, when our data are precise enough to probe the first excited state. © 2017 American Physical Society.