Statistical Neutron Emission Model for Neutrino Nuclear Response

I.H Hashim,K.C Wei,H Ejiri,W.N Amelia,S.A Hamzah,S.S Saroni,F Othman,M.H Koh,G Krishnan,F Mohd Noor

doi:10.1051/epjconf/201715600005

I.H Hashim, K.C Wei + Show 8 more

Open Access

https://doi.org/10.1051/epjconf/201715600005

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Abstract

The studies of neutrino fundamental properties are widely investigated by double beta decay and inverse beta decay. Recent muon capture experiment provides promising ways to directly evaluate the neutrino nuclear responses. This study provides theoretical explanation for neutrino nuclear responses by muon capture experiment. The effects of muon binding energy towards nuclear excitation region and pre-equilibrium (PEQ) and equilibrium (EQ) neutron decay mode will be discussed. The interpretation of muon strength model by comparison of calculator output and recent experimental data may provide relevant information towards determination of nuclear matrix element (NME) and its missing parameter.

Highlights

Theoretical calculations of the weak responses are challenging since they are sensitive to the nuclear correlations and nuclear medium effects
The ß+ strengths are obtained by measuring prompt [6] and delayed gamma rays [9,10,11] from (μ,xn) reactions with x being the number of the emitted neutrons
The prompt gamma rays originating from bound states are excited byμcapture help the probing of ß+ responses at low lying bound states [6,9]

Summary

Introduction

Theoretical calculations of the weak responses (matrix elements) are challenging since they are sensitive to the nuclear correlations and nuclear medium effects. Observation of M(ß+) are hard as of no high energy resolution nuclear probes It has been pointed out in early 1970s that muon capture reactions (MCR) are alternative to probe the ß+ responses [1]. Theμcapture strength distribution as a function of the excitation energy is derived so as to reproduce the measured reaction branches on the basis of the equilibrium (EQ) and PEQ neutron emission mechanism. The results of this investigation will shed light on the unknown effective axial-vector coupling constant, gA,eff and spin iso-spin nuclear parameter, gp which lead to big uncertainties in determining the nuclear matrix element. It will help the theorists group to decide whether these unknown parameters are suitable with their model or requires adjustment to their parameters

Theory of Neutron Statistical Model

Results and Discussion

Conclusions