Strong-Isospin Violation in the Neutron-Proton Mass Difference from Fully-Dynamical Lattice QCD and PQQCD

Journal Article · Sun Apr 01 04:00:00 EDT 2007 · Nuclear Physics B

DOI:https://doi.org/10.1016/j.nuclphysb.2006.12.023· OSTI ID:882225

Beane, Silas; Orginos, Konstantinos; Savage, Martin

We determine the strong-isospin violating component of the neutron-proton mass difference from fully-dynamical lattice QCD and partially-quenched QCD calculations of the nucleon mass, constrained by partially-quenched chiral perturbation theory at one-loop level. The lattice calculations were performed with domain-wall valence quarks on MILC lattices with rooted staggered sea-quarks at a lattice spacing of b = 0.125 fm, lattice spatial size of L = 2.5 fm and pion masses ranging from m{sub {pi}} {approx} 290 MeV to {approx} 350 MeV. At the physical value of the pion mass, we predict M{sub n}-M{sub p}|{sup d-u} = 2.26 {+-} 0.57 {+-} 0.42 {+-} 0.10 MeV where the first error is statistical, the second error is due to the uncertainty in the ratio of light-quark masses, {eta} = m{sub u}/m{sub d}, determined by MILC, and the third error is an estimate of the systematic due to chiral extrapolation.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA
• Sponsoring Organization: USDOE - Office of Energy Research (ER)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 882225
• Report Number(s): JLAB-THY-06-494; DOE/ER/40150-3861
• Journal Information: Nuclear Physics B, Journal Name: Nuclear Physics B Vol. 768
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
EXTRAPOLATION
MASS DIFFERENCE
NUCLEONS
PERTURBATION THEORY
PIONS
QUANTUM CHROMODYNAMICS
QUARKS
VALENCE