Two-pion exchange contributions to nuclear charge asymmetry

Journal Article · Sat Apr 01 04:00:00 EST 1995 · Bulletin of the American Physical Society

OSTI ID:375035

Coon, S A; Niskanen, J A

An explicit 2{pi} exchange (TPE) potential based on non-relativistic {pi}NN and {pi}{Delta}N vertices with the baryon mass differences taken into account in the vertices is extended to the study of mirror nuclear systems. For the latter study, one must also include baryon mass differences in the intermediate state energy denominators. The TPE potential includes box and crossed box diagrams with two nucleons and those with one nucleon and one {Delta}. Nuclear charge asymmetry is characterized, in part, by a positive value for the difference {Delta}a = {vert_bar}a{sub nn}{vert_bar} {minus} {vert_bar}a{sub pp}{vert_bar} {approx} O(1 fm) and a positive value for the {sup 3}H - {sup 3}He binding energy difference {Delta}E {approx} O(100 keV). The charge asymmetry from baryon mass differences in the vertices is small on this scale and in the wrong direction compared to the empirical values. The contribution from baryon mass differences in the intermediate state energy denominators is positive and is of the order of the empirical scales, in contrast to the previous estimate of {Delta}a {approx} +0.3 fm obtained from an SU(2) symmetric covariant field theoretical potential. This discrepancy between models of TPE is being investigated.

• OSTI ID: 375035
• Report Number(s): CONF-9304297--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 2 Vol. 40; ISSN 0003-0503; ISSN BAPSA6
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ASYMMETRY
EXCHANGE INTERACTIONS
HELIUM 3
MIRROR NUCLEI
PIONS
TRITIUM