Valence quark contributions for the {gamma}N{yields}P{sub 11}(1440) form factors

Journal Article · Thu Apr 01 04:00:00 EDT 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.81.074020· OSTI ID:21409482

Ramalho, G ^[1]; Tsushima, K ^[2]

---

1. Centro de Fisica Teorica de Particulas, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)
2. Excited Baryon Analysis Center (EBAC) and Theory Center, Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)

Using a covariant spectator quark model we estimate valence quark contributions to the F{sub 1}*(Q{sup 2}) and F{sub 2}*(Q{sup 2}) transition form factors for the {gamma}N{yields}P{sub 11}(1440) reaction. The Roper resonance, P{sub 11}(1440), is assumed to be the first radial excitation of the nucleon. The present model requires no extra parameters except for those already fixed by previous studies of the nucleon. Our results are consistent with the experimental data in the high Q{sup 2} region, and those from lattice QCD. We also estimate the meson cloud contributions, focusing on the low Q{sup 2} region, where they are expected to be dominant.

• OSTI ID: 21409482
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 7 Vol. 81; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BARYONS
BOSONS
COMPOSITE MODELS
DIMENSIONLESS NUMBERS
ELEMENTARY PARTICLES
ENERGY-LEVEL TRANSITIONS
EXCITATION
FERMIONS
FIELD THEORIES
FORM FACTORS
HADRONS
MATHEMATICAL MODELS
MESONS
N BARYONS
N*BARYONS
N-1440 BARYONS
NUCLEONS
PARTICLE MODELS
PARTICLE PROPERTIES
QUANTUM CHROMODYNAMICS
QUANTUM FIELD THEORY
QUARK MODEL
QUARKS