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Title: Lattice calculation of electric dipole moments and form factors of the nucleon

Abstract

In this paper, we analyze commonly used expressions for computing the nucleon electric dipole form factors (EDFF) $$F_3$$ and moments (EDM) on a lattice and find that they lead to spurious contributions from the Pauli form factor $$F_2$$ due to inadequate definition of these form factors when parity mixing of lattice nucleon fields is involved. Using chirally symmetric domain wall fermions, we calculate the proton and the neutron EDFF induced by the CP-violating quark chromo-EDM interaction using the corrected expression. In addition, we calculate the electric dipole moment of the neutron using a background electric field that respects time translation invariance and boundary conditions, and we find that it decidedly agrees with the new formula but not the old formula for $$F_3$$. In conclusion, we analyze some selected lattice results for the nucleon EDM and observe that after the correction is applied, they either agree with zero or are substantially reduced in magnitude, thus reconciling their difference from phenomenological estimates of the nucleon EDM.

Authors:
 [1];  [2];  [3];  [4];  [5];  [6]
  1. Univ. of Connecticut, Storrs, CT (United States). Physics Dept.
  2. Kyoto Univ. (Japan). Center for Gravitational Physics. Yukawa Inst. for Theoretical Physics; Univ. of Tsukuba (Japan). Center for Computational Sciences
  3. Univ. of Connecticut, Storrs, CT (United States). Physics Dept.; Brookhaven National Lab. (BNL), Upton, NY (United States). RIKEN/BNL Research Center
  4. Brookhaven National Lab. (BNL), Upton, NY (United States). Physics Dept. RIKEN/BNL Research Center
  5. Brookhaven National Lab. (BNL), Upton, NY (United States). RIKEN/BNL Research Center
  6. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Univ. of California, Santa Barbara, CA (United States). Kavli Inst. for Theoretical Physics; Stony Brook Univ., NY (United States). Dept. of Physics and Astronomy; Brookhaven National Lab. (BNL), Upton, NY (United States). RIKEN/BNL Research Center
Publication Date:
Research Org.:
Univ. of Connecticut, Storrs, CT (United States); Kyoto Univ. (Japan); Brookhaven National Lab. (BNL), Upton, NY (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26); USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25); National Science Foundation (NSF); Ministry of Education, Culture, Sports, Science and Technology (MEXT) (Japan)
OSTI Identifier:
1374994
Report Number(s):
JLAB-THY-17-2449; DOE/OR/23177-4122; arXiv:1701.07792; RBRC-1226; BNL-114795-2017-JA
Journal ID: ISSN 2470-0010
Grant/Contract Number:
FG02-92ER40716; AC02-98CH10886; SC0012704; AC05-06OR23177; JP16H03978; JP17H02906; 26400261; NSF PHY11-25915
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 96; Journal Issue: 1; Journal ID: ISSN 2470-0010
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; electric moment; form factors; lattice QCD; CP violation; chiral symmetry; EDM; EDFF; parity; lattice; CP

Citation Formats

Abramczyk, M., Aoki, S., Blum, T., Izubuchi, T., Ohki, H., and Syritsyn, S. Lattice calculation of electric dipole moments and form factors of the nucleon. United States: N. p., 2017. Web. doi:10.1103/PhysRevD.96.014501.
Abramczyk, M., Aoki, S., Blum, T., Izubuchi, T., Ohki, H., & Syritsyn, S. Lattice calculation of electric dipole moments and form factors of the nucleon. United States. doi:10.1103/PhysRevD.96.014501.
Abramczyk, M., Aoki, S., Blum, T., Izubuchi, T., Ohki, H., and Syritsyn, S. 2017. "Lattice calculation of electric dipole moments and form factors of the nucleon". United States. doi:10.1103/PhysRevD.96.014501.
@article{osti_1374994,
title = {Lattice calculation of electric dipole moments and form factors of the nucleon},
author = {Abramczyk, M. and Aoki, S. and Blum, T. and Izubuchi, T. and Ohki, H. and Syritsyn, S.},
abstractNote = {In this paper, we analyze commonly used expressions for computing the nucleon electric dipole form factors (EDFF) $F_3$ and moments (EDM) on a lattice and find that they lead to spurious contributions from the Pauli form factor $F_2$ due to inadequate definition of these form factors when parity mixing of lattice nucleon fields is involved. Using chirally symmetric domain wall fermions, we calculate the proton and the neutron EDFF induced by the CP-violating quark chromo-EDM interaction using the corrected expression. In addition, we calculate the electric dipole moment of the neutron using a background electric field that respects time translation invariance and boundary conditions, and we find that it decidedly agrees with the new formula but not the old formula for $F_3$. In conclusion, we analyze some selected lattice results for the nucleon EDM and observe that after the correction is applied, they either agree with zero or are substantially reduced in magnitude, thus reconciling their difference from phenomenological estimates of the nucleon EDM.},
doi = {10.1103/PhysRevD.96.014501},
journal = {Physical Review D},
number = 1,
volume = 96,
place = {United States},
year = 2017,
month = 7
}

Journal Article:
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  • Here, we analyze commonly used expressions for computing the nucleon electric dipole form factors (EDFF) F 3 and moments (EDM) on a lattice and find that they lead to spurious contributions from the Pauli form factor F 2 due to inadequate definition of these form factors when parity mixing of lattice nucleon fields is involved. Using chirally symmetric domain wall fermions, we calculate the proton and the neutron EDFF induced by the CP-violating quark chromo-EDM interaction using the corrected expression. In addition, we calculate the electric dipole moment of the neutron using a background electric field that respects time translationmore » invariance and boundary conditions, and we find that it decidedly agrees with the new formula but not the old formula for F 3. Finally, we analyze some selected lattice results for the nucleon EDM and observe that after the correction is applied, they either agree with zero or are substantially reduced in magnitude, thus reconciling their difference from phenomenological estimates of the nucleon EDM.« less
  • We perform the calculation of the nucleon dipole magnetic moment in full detail using the Gordon decomposition of the free quark current. This calculation has become necessary because of frequent misuse of the Gordon decomposition by some authors in computing the nucleon dipole magnetic moment.
  • The nucleon`s strange form factors {ital G}{sup {ital S}}{sub {ital E}}({ital Q}{sup 2}) and {ital G}{sup {ital S}}{sub {ital M}}({ital Q}{sup 2}), and the neutron`s electromagnetic form factors {ital G}{sup {ital n}}{sub {ital E}}({ital Q}{sup 2}) and {ital G}{sup {ital n}}{sub {ital M}}({ital Q}{sup 2}), are obtained from the light-cone quark model including the quark anomalous moments due to the meson-loop corrections. The anomalous magnetic and strange moments of the constituent quark make significant contributions: Without them, {ital G}{sup {ital S}}{sub {ital M}}(0) vanishes, {ital r}{sup 2}{sub {ital S}} becomes positive, and the neutron charge radius is too small.