Weak decay of hypernuclei

Journal Article · Tue Jul 01 04:00:00 EDT 1997 · Physical Review, C

DOI:https://doi.org/10.1103/PhysRevC.56.339· OSTI ID:531920

Parreno, A; Ramos, A ^[1]; Bennhold, C ^[2]

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1. Departament dEstructura i Constituents de la Materia, Facultat de Fisica, Diagonal 647, E-08028 Barcelona (Spain)
2. Center of Nuclear Studies, Department of Physics, The George Washington University, Washington, DC 20052 (United States)

The nonmesonic weak decay of {Lambda} hypernuclei is studied in a shell model framework. A complete strangeness-changing weak {Lambda}N{r_arrow}NN transition potential, based on one boson exchange, is constructed by including the exchange of the pseudoscalar mesons {pi}, K, {eta} as well as the vector mesons {rho},{omega}, and K{sup {asterisk}}, whose weak-coupling constants are obtained from soft meson theorems and SU(6){sub w}. General expressions for nucleons in arbitrary shells are obtained. The transition matrix elements include realistic {Lambda}N short-range correlations and NN final state interactions based on the Nijmegen baryon-baryon potential. The decay rates are found to be especially sensitive to the inclusion of the strange mesons K and K{sup {asterisk}} even though the role of kaon exchange is found to be reduced with recent couplings obtained from one-loop corrections to the leading order in chiral perturbation theory. With the weak couplings used in this study the rates remain dominated by the pion-exchange mechanism since the contributions of heavier mesons either cancel each other or are suppressed by form factors and short-range correlations. The total decay rate therefore remains in agreement with present measurements. However, the partial rates which are even more sensitive to the inclusion of heavier mesons cannot be reconciled with the data. The proton asymmetry changes by 50{percent} once heavier mesons are included and agrees with the available data. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 531920
• Journal Information: Physical Review, C, Journal Name: Physical Review, C Journal Issue: 1 Vol. 56; ISSN PRVCAN; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CHIRAL SYMMETRY
COUPLING CONSTANTS
ETA MESONS
FINAL-STATE INTERACTIONS
FORM FACTORS
HYPERNUCLEI
KAONS
LAMBDA BARYONS
NUCLEAR DECAY
NUCLEAR FORCES
NUCLEON-HYPERON INTERACTIONS
NUCLEONS
OBE MODEL
PERTURBATION THEORY
PIONS
PSEUDOSCALAR MESONS
SHELL MODELS
STRANGENESS
SU-6 GROUPS
TRANSITION AMPLITUDES
VECTOR MESONS