nucl-th digest · May 28, 2018

Tensor correlations in $^{4}$ He and $^{8}$ Be with antisymmetrized quasi cluster model

H. Matsuno · Y. Kanada-En'yo · N. Itagaki

In this paper, we extend the framework of improved version of simplified method to take into account the tensor contribution ( $i$ SMT) and propose AQCM-T, tensor version of antisymmetrized quasi cluster model (AQCM). Although AQCM-T is phenomenological, we can treat the $^{3} S$ - $^{3} D$ coupling in the deuteron-like $T = 0$ $N N$ -pair induced by the tensor interaction in a very simplified way, which allows us to proceed to heavier nuclei. Also we propose a new effective interaction, V2m, where the triplet-even channel of the Volkov No.2 interaction is weakened to 60% so as to reproduce the binding energy of $^{4}$ He after including the tensor term of a realistic interaction. Using AQCM-T and the new interaction, the significant tensor contribution in $^{4}$ He is shown, which is almost comparable the central interaction, where $D$ -state mixes by 8% to the major $S$ -state. The AQCM-T model with the new interaction is also applied to $^{8}$ Be. It is found that the tensor suppression gives significant contribution to the short-range repulsion between two {\alpha} clusters.

nucl-thPRC(2018)·9 citations

Quenching of nuclear matrix elements for

0 ν β β

decay by chiral two-body currents

We examine the leading effects of two-body weak currents from chiral effective field theory on the matrix elements governing neutrinoless double-beta decay. In the closure approximation these effects are generated by the product of a one-body current with a two-body current, yielding both two- and three-body operators. When the three-body operators are considered without approximation, they quench matrix elements by about 10%, less than suggested by prior work, which neglected portions of the operators. The two-body operators, when treated in the standard way, can produce much larger quenching. In a consistent effective field theory, however, these large effects become divergent and must be renormalized by a contact operator, the coefficient of which we cannot determine at present.

nucl-thPRC(2018)·62 citations

Monday·May 28, 2018

Tensor correlations in $^{4}$ He and $^{8}$ Be with antisymmetrized quasi cluster model

Quenching of nuclear matrix elements for $0 ν β β$ decay by chiral two-body currents

Affiliations

Tensor correlations in 4He and 8Be with antisymmetrized quasi cluster model

Quenching of nuclear matrix elements for 0νββ decay by chiral two-body currents

Affiliations

Tensor correlations in $^{4}$ He and $^{8}$ Be with antisymmetrized quasi cluster model

Quenching of nuclear matrix elements for $0 ν β β$ decay by chiral two-body currents