Spin Polarization inγd→ $\vec{n}$p

S.I Ando,K Kubodera,Y H Song,C H Hyun

doi:10.1051/epjconf/20122002003

S.I Ando, K Kubodera + Show 2 more

Open Access

https://doi.org/10.1051/epjconf/20122002003

Copy DOI

Abstract

The study of spin observables is an important and active issue in low energy nuclear physics. In this contribution we report our recent calculation on the γd → p reaction at low photon energies. Our main goal is to calculate the neutron spin polarization Py′ , but we also calculate the total cross section as well as the differential cross section. Although the results for the total and differential cross sections are found to agree reasonably well with the data, the results for Py′ show significant discrepancy with the experiment. We comment on this discrepancy.

Highlights

With high-precision nuclear potentials that are available, we can calculate accurately the binding energies, wave functions and a large number of reaction observables for few-nucleon systems.the full explanation of spin observables in few-nucleon systems still remains a challenging problem
We report our recent calculation on the neutron spin asymmetry Py in the dγ
We conclude that our dEFT calculation up to next-to leading order (NLO), which contains no adjustable parameters after the two low-energy constants (LECs) (L1 and L2) have been fixed, can reproduce the total cross section data reasonably well

Summary

Introduction

With high-precision nuclear potentials that are available, we can calculate accurately the binding energies, wave functions and a large number of reaction observables for few-nucleon systems. In SNPA, the nuclear wave functions are generated with the use of high-precision phenomenological nucleon-nucleon potentials that accurately reproduce thousands of neutron-proton and proton-proton scattering data along with the deuteron properties. For the spin polarization Py , there is a large discrepancy between the state-of-the-art SNPA calculation [2] and the data This discrepancy gives a further indication of the seriousness of the “Py puzzle”, and one is led to ask whether the problem lies with theory or experiment. It is hoped that the present study will provide useful information regarding the Py puzzle

Formalism

Transition Amplitudes

Differential cross section and neutron spin polarization

Results and Discussion

14 This work

Conclusions