Mesonic cloud contribution to the nucleon and delta masses

Journal Article · Fri Feb 02 04:00:00 EST 2001 · Phys.Rev.C

OSTI ID:775026

Ernst, D J

Pion-nucleon elastic scattering in the dominant P{sub 33} channel is examined in the model in which the interaction is of the form {pi} + N {leftrightarrow} N, {Delta}(1232). A Low equation formalism is employed which uses covariant phase space and normalizations, a finite nucleon mass, and generates the invariant scattering amplitude which is free of kinematic singularities. New expressions are found for the elastic pion-nucleon scattering amplitude which differ from existing formula both in the kinematics and in the treatment of the renormalization of the nucleon mass and coupling constant. Fitting the model to the phase shifts in the P{sub 33} channel does not uniquely fix the parameters of the model. The cutoff for the pion-nucleon form factor is found to lie in the range {beta} = 750 {+-} 350 MeV/c. The masses of the nucleon and the {Delta} which would arise if there were no coupling to mesons are found to be m{sub N}{sup (0)} = 1179 {+-} 218 MeV and m{sub {Delta}}{sup (0)} = 1491 {+-} 198 MeV. The difference in these bare masses, a quantity which would be accounted for by a residual gluon interaction, is found to be {delta}m{sup (0)} = 341 {+-} 116 MeV.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (US)
• Sponsoring Organization: USDOE Office of Energy Research (ER) (US)
• DOE Contract Number: AC05-84ER40150
• OSTI ID: 775026
• Report Number(s): JLAB-THY-01-04; DOE/ER/40150-1808; nucl-th/0102033
• Journal Information: Phys.Rev.C, Journal Name: Phys.Rev.C Vol. 64
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CLOUDS
COUPLING CONSTANTS
ELASTIC SCATTERING
FORM FACTORS
LOW EQUATION
NUCLEONS
PHASE SHIFT
PHASE SPACE
SCATTERING AMPLITUDES