6533b827fe1ef96bd1286839

RESEARCH PRODUCT

Renormalization of the weak hadronic current in the nuclear medium

Teemu SiiskonenMorten Hjorth-jensenJouni Suhonen

subject

PhysicsNuclear and High Energy PhysicsParticle physicsNuclear Theory010308 nuclear & particles physicsHigh Energy Physics::LatticeNuclear TheoryMomentum transferHadronFOS: Physical sciencesInverseType (model theory)7. Clean energy01 natural sciencesNuclear Theory (nucl-th)RenormalizationPseudoscalar0103 physical sciencesNuclear Experiment010306 general physicsNucleonPseudovector

description

The renormalization of the weak charge-changing hadronic current as a function of the reaction energy release is studied at the nucleonic level. We have calculated the average quenching factors for each type of current (vector, axial vector and induced pseudoscalar). The obtained quenching in the axial vector part is, at zero momentum transfer, 19% for the sd shell and 23% in the fp shell. We have extended the calculations also to heavier systems such as $^{56}$Ni and $^{100}$Sn, where we obtain stronger quenchings, 44% and 59%, respectively. Gamow--Teller type transitions are discussed, along with the higher order matrix elements. The quenching factors are constant up to roughly 60 MeV momentum transfer. Therefore the use of energy-independent quenching factors in beta decay is justified. We also found that going beyond the zeroth and first order operators (in inverse nucleon mass) does not give any substantial contribution. The extracted renormalization to the ratio $C_P/C_A$ at q=100 MeV is -3.5%, -7.1$%, -28.6%, and +8.7% for mass 16, 40, 56, and 100, respectively.

https://doi.org/10.1103/physrevc.63.055501