Two-Pion Exchange Nucleon-Nucleon Potential: Relativistic Chiral Expansion

Journal Article · Thu Aug 01 04:00:00 EDT 2002

OSTI ID:798245

Higa, R; Robilotta, M R

We present a relativistic procedure for the chiral expansion of the two-pion exchange component of the NN potential, which emphasizes the role of intermediate pi N subamplitudes. The relationship between power counting in pi N and NN processes is discussed and results are expressed directly in terms of observable subthreshold coefficients. Interactions are determined by one and two-loop diagrams, involving pions, nucleons and other degrees of freedom, frozen into empirical subthreshold coefficients. The full evaluation of these diagrams produces amplitudes containing many different loop integrals. Their simplification by means of relations among these integrals leads to a set of intermediate results. Subsequent truncation to order(q{sup 4}) yields the relativistic potential, which depends on four loop integrals, representing bubble, triangle, crossed box and box diagrams. The bubble and triangle integrals are the same as in pi N scattering and we have shown that they also determine the chiral structures of box and crossed box integrals. Relativistic threshold effects were found to begin to contribute at order(q{sup 5}) only and our results should coincide with those of the standard heavy baryon approach. Checking this explicitly, we found differences due to the Goldberger-Treiman discrepancy and terms of order(q{sup 3}), possibly associated with the iteration of the OPEP.

• 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: 798245
• Report Number(s): JLAB-THY-02-30; DOE/ER/40150-2124
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
AMPLITUDES
BARYONS
BUBBLES
DEGREES OF FREEDOM
ENANTIOMORPHS
EVALUATION
NUCLEON-NUCLEON POTENTIAL
NUCLEONS
PIONS
SCATTERING