Photon asymmetries in $nd\rightarrow$ $^3Hγ$ using EFT($π/!/!/!/$) 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 $np\rightarrow$ $dγ$ $A^{np}_γ$, the circular polarization of outgoing photon in $np\rightarrow$ $dγ$ $P^{np}_γ$, the neutron spin rotation in hydrogen $\frac{1}ρ\frac{dϕ^{np}}{dl}$, the neutron spin rotation in deuterium $\frac{1}ρ\frac{dϕ^{nd}}{dl}$ and the circular polarization of $γ$-emission in $nd\rightarrow$ $^3Hγ$ $P^{nd}_γ$ 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 $a^{nd}_γ$ and the photon asymmetry in relation to deuteron polarization $A^{nd}_γ$ in $nd\rightarrow$ $^3Hγ$ process. We finally compare our EFT($//!/!/!/pi$) photon asymmetries results with the experimental values and the previous calculations based on the DDH model.