Quark pseudoscalar vertex and quark mass function with clover fermions: Spontaneous symmetry breaking, operator product expansion, symmetry restoration at small volume

Journal Article · Sat May 01 00:00:00 EDT 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.81.094504· OSTI ID:21409963

Boucaud, Ph; Leroy, J -P; Le Yaouanc, A; Micheli, J; Pene, O ^[1]; Rodriguez-Quintero, J ^[2]

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1. Laboratoire de Physique Theorique, Universite de Paris XI, Batiment 210, 91405 Orsay Cedex (France)
2. Departamento Fisica Aplicada, Fac. Ciencias Experimentales, Universidad de Huelva, 21071 Huelva (Spain)

We study the quark mass function on hypercubic lattices in a large range of physical volumes and cutoffs. To avoid the very large Wilson term artefact, we exploit the relation between the quark mass function and the pseudoscalar vertex in the continuum. We extrapolate to the chiral limit. In function of the physical volume, we observe a striking discontinuity in the properties of chiral extrapolation around a physical volume L{sub c{approx_equal}}6 GeV{sup -1}=1.2 fm. It is present in the quark mass function, which collapses to zero, as well as in the pion mass and the quark condensate as directly calculated from the pseudoscalar correlator. It is strongly reminiscent of the phenomenon of chiral symmetry restoration observed by Neuberger and Narayanan at N{sub C}={infinity} around the same physical length. In the case of spontaneous symmetry breaking, we confirm that the operator product expansion of the quark mass function, involving the quark condensate, is not operative at the available momenta, even taking into account the unusually large high order corrections to the Wilson coefficient calculated by Chetyrkin and Maier; the gap remains large, around a factor 2, even at the largest momenta available to us (p{approx_equal}6 GeV).

• OSTI ID: 21409963
• Journal Information: Physical Review. D, Particles Fields, Vol. 81, Issue 9; Other Information: DOI: 10.1103/PhysRevD.81.094504; (c) 2010 The American Physical Society; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CHIRAL SYMMETRY
CHIRALITY
CORRECTIONS
EXTRAPOLATION
GEV RANGE 01-10
MASS
OPERATOR PRODUCT EXPANSION
PIONS
QUARK CONDENSATION
QUARKS
SYMMETRY BREAKING
BOSONS
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
GEV RANGE
HADRONS
MATHEMATICAL SOLUTIONS
MESONS
NUMERICAL SOLUTION
PARTICLE PROPERTIES
PSEUDOSCALAR MESONS
SERIES EXPANSION
SYMMETRY