Null-plane Bethe-Salpeter dynamics: Mass spectra, decay constants of pseudoscalar mesons, and the pion form factor

Journal Article · Sat Sep 01 04:00:00 EDT 1990 · Physical Review, D (Particles Fields); (USA)

DOI:https://doi.org/10.1103/PhysRevD.42.1604· OSTI ID:6233251

Gupta, K K; Mitra, A N; Singh, N N ^[1]

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1. Department of Physics, University of Delhi, Delhi (India)

A new relativistic definition of the reduced mass ({mu}{sub 12}) of a {ital q{bar q}} pair, so as to be in conformity with the standard Wightman-Garding definition of its relative four-momenta {ital q}{sub {mu}}, is introduced into the kernel of an ongoing Bethe-Salpeter (BS) program on a two-tier basis. The new definition of {mu}{sub 12} (involving the hadron mass {ital M}) is found to produce a natural Regge asymptotic behavior ({ital M}{sup 2}{approximately}{ital N}) in the hadron mass spectra, while retaining the property of an asymptotically linear ({approximately}{ital r}) confinement in the three-dimensional structure of the BS kernel. The relativistic structure of {mu}{sub 12} is responsible for a significant improvement in the fits to the ground-state masses of {ital q{bar q}} and {ital Q{bar q}} mesons as compared to its nonrelativistic definition {ital m}{sub 1}{ital m}{sub 2}/({ital m}{sub 1}+{ital m}{sub 2}). The leptonic decay constants {ital f}{sub {ital p}} and the charge radii thus calculated are also in excellent agreement with data ({pi},{ital k}) where available, while {ital f}{sub {ital p}} predictions for {ital Q{bar q}} mesons have good overlap with recent lattice predictions. Further, the scaling property ({approximately}{ital k}{sub {mu}}{sup {minus}2}) of the hadron's electromagnetic form factor at large {ital k}{sup 2} is a consequence of the on-shell'' form of its null-plane wave function. All these results (which are indicated in the barest outline) are preceded by a perspective summary of the theoretical premises and practical working of the BS equation with a four-fermion interaction kernel as a necessary background on a two-tier basis.

• OSTI ID: 6233251
• Journal Information: Physical Review, D (Particles Fields); (USA), Journal Name: Physical Review, D (Particles Fields); (USA) Vol. 42:5; ISSN PRVDA; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

645202 -- High Energy Physics-- Particle Interactions & Properties-Theoretical-- Electromagnetic Interactions & Properties
645203* -- High Energy Physics-- Particle Interactions & Properties-Theoretical-- Weak Interactions & Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BASIC INTERACTIONS
BETHE-SALPETER EQUATION
BOSON EXPANSION
BOSON-EXCHANGE MODELS
BOSONS
CHIRAL SYMMETRY
COUPLING CONSTANTS
DECAY
DYSON REPRESENTATION
ELECTRODYNAMICS
ELECTROMAGNETIC FORM FACTORS
ELEMENTARY PARTICLES
EQUATIONS
FIELD THEORIES
FORM FACTORS
FUNCTIONS
GAUGE INVARIANCE
HADRONS
INTERACTIONS
INVARIANCE PRINCIPLES
LADDER APPROXIMATION
LEPTONIC DECAY
MASS SPECTRA
MATHEMATICAL MODELS
MESONS
OBE MODEL
PARTICLE DECAY
PARTICLE MODELS
PARTICLE PROPERTIES
PERIPHERAL MODELS
PIONS
PSEUDOSCALAR MESONS
QUANTUM ELECTRODYNAMICS
QUANTUM FIELD THEORY
QUARKONIUM
SPECTRA
SYMMETRY
SYMMETRY BREAKING
VERTEX FUNCTIONS
WAVE FUNCTIONS
WEAK INTERACTIONS
WEAK PARTICLE DECAY