Quark orbital angular momentum from lattice QCD

Journal Article · Fri Dec 01 00:00:00 EST 2000 · Physical Review D

DOI:https://doi.org/10.1103/PhysRevD.62.114504· OSTI ID:40205220

Mathur, N; Dong, S J; Liu, K F; Mankiewicz, L; Mukhopadhyay, N C

We calculate the quark orbital angular momentum of the nucleon from the quark energy-momentum tensor form factors on the lattice with the quenched approximation. The disconnected insertion is estimated stochastically which employs the Z{sub 2} noise with an unbiased subtraction. This reduced the error by a factor of 3--4 with negligible overhead. The total quark contribution to the proton spin is found to be 0.30{+-}0.07. From this and the quark spin content we deduce the quark orbital angular momentum to be 0.17{+-}0.06 which is {approx}34% of the proton spin. We further predict that the gluon angular momentum is 0.20{+-}0.07; i.e., {approx}40% of the proton spin is due to the glue.

• Sponsoring Organization: (US)
• OSTI ID: 40205220
• Journal Information: Physical Review D, Vol. 62, Issue 11; Other Information: DOI: 10.1103/PhysRevD.62.114504; Othernumber: PRVDAQ000062000011114504000001; 033023PRD; PBD: 1 Dec 2000; ISSN 0556-2821
• Publisher: The American Physical Society
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANGULAR MOMENTUM
ENERGY-MOMENTUM TENSOR
FORM FACTORS
GLUONS
NUCLEONS
ORBITAL ANGULAR MOMENTUM
PROTONS
QUANTUM CHROMODYNAMICS
QUARKS
SPIN