Photon Asymmetries in $${nd\rightarrow}$$ n d → 3 Hγ Using EFT( $${/\!\!\!\pi}$$ / π ) Approach

Abstract

The parity-violating Lagrangian of the weak nucleon-nucleon ($NN$) interaction in the pionless effective field theory (EFT($//!/!/!/pi$)) approach contains five independent unknown low-energy coupling constants (LECs). The photon asymmetry with respect to neutron polarization in $np\rightarrow$ $d\gamma$ $A^{np}_\gamma$, the circular polarization of outgoing photon in $np\rightarrow$ $d\gamma$ $P^{np}_\gamma$, the neutron spin rotation in hydrogen $\frac{1}{\rho}\frac{d\phi^{np}}{dl}$, the neutron spin rotation in deuterium $\frac{1}{\rho}\frac{d\phi^{nd}}{dl}$ and the circular polarization of $\gamma$-emission in $nd\rightarrow$ $^3H\gamma$ $P^{nd}_\gamma$ are the parity-violating observables which have been recently calculated in terms of parity-violating LECs in the EFT($//!/!/!/pi$) framework. We obtain the LECs by matching the parity-violating observables to the Desplanques, Donoghue, and Holstein (DDH) best value estimates. Then, we evaluate photon asymmetry with respect to the neutron polarization $a^{nd}_\gamma$ and the photon asymmetry in relation to deuteron polarization $A^{nd}_\gamma$ in $nd\rightarrow$ $^3H\gamma$ process. We finally compare our EFT($//!/!/!/pi$) photon asymmetries results with the experimental values and the previous calculations based on the DDH model.