Matrix elements of four-quark operators and \Delta L=2 hyperon decays

TL;DR

This paper calculates hadronic matrix elements of four-quark operators relevant for neutrinoless double beta decays of hyperons using the MIT bag model, providing insights into lepton number violation processes.

Contribution

It introduces a method to compute these matrix elements without relying on the factorization approximation, enhancing the accuracy of decay rate predictions.

Findings

Matrix elements computed without factorization approximation

Estimated decay rate for   p e- e- decay

Comparison of results with traditional approaches

Abstract

The study of neutrinoless double beta decays of nuclei and hyperons require the calculation of hadronic matrix elements of local four-quark operators that change the total charge by two units \Delta Q=2 . Using a low energy effective Lagrangian that induces these transitions, we compute these hadronic matrix elements in the framework of the MIT bag model. As an illustrative example we evaluate the amplitude and transition rate of \Sigma- -> p e- e-, a decay process that violates lepton number by two units (\Delta L=2). The relevant matrix element is evaluated without assuming the usual factorization approximation of the four-quark operators and the results obtained in both approaches are compared.