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Title: Isovector and isoscalar tensor charges of the nucleon from lattice QCD

Here, we present results for the isovector and flavor diagonal tensor charges gu–dT, guT, gdT, and gsT needed to probe novel tensor interactions at the TeV scale in neutron and nuclear β-decays and the contribution of the quark electric dipole moment (EDM) to the neutron EDM. The lattice QCD calculations were done using nine ensembles of gauge configurations generated by the MILC collaboration using the HISQ action with 2+1+1 dynamical flavors. These ensembles span three lattice spacings a ≈ 0.06, 0.09 and 0.12 fm and three quark masses corresponding to the pion masses Mπ ≈ 130, 220 and 310 MeV. Using estimates from these ensembles, we quantify all systematic uncertainties and perform a simultaneous extrapolation in the lattice spacing, volume and light quark masses for the connected contributions. The final estimates of the connected nucleon (proton) tensor charge for the isovector combination is gu–dT = 1.020(76) in the MS¯ scheme at 2 GeV. The additional disconnected quark loop contributions needed for the flavor-diagonal matrix elements are calculated using a stochastic estimator employing the truncated solver method with the all-mode-averaging technique. We find that the size of the disconnected contribution is smaller than the statistical error in the connected contribution. Thismore » allows us to bound the disconnected contribution and include it as an additional uncertainty in the flavor-diagonal charges. After a continuum extrapolation, we find guT = 0.774(66), gdT = –0.233(28) and gu+dT = 0.541(67). The strangeness tensor charge, that can make a significant contribution to the neutron EDM due to the large ratio ms/mu,d, is gsT = 0.008(9) in the continuum limit.« less
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [4] ;  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Univ. of Washington, Seattle, WA (United States)
  3. John von Neumann Institute for Computing, DESY, Zeuthen (Germany)
  4. Univ. of California, Berkeley, CA (United States)
Publication Date:
OSTI Identifier:
1248743
Report Number(s):
LA-UR-15-23801
Journal ID: ISSN 1550-7998; PRVDAQ
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Physical Review. D, Particles, Fields, Gravitation and Cosmology
Additional Journal Information:
Journal Volume: 92; Journal Issue: 9; Journal ID: ISSN 1550-7998
Research Org:
Los Alamos National Laboratory (LANL)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS Atomic and Nuclear Physics; Nucleon charges, Disconnected quark loops, quark EDM