Parity-violating photon circular polarization in nd $\rightarrow$ ³H$\gamma$ with effective field theory at thermal energy

Abstract.

We study the parity-violating effects in nd $\rightarrow$ ³H$\gamma$ process using pionless effective field theory (EFT( /$\pi$) at thermal energy. For the weak NN interaction the parity-violating Lagrangian contains five independent low-energy coupling constants (LECs). One can fix the coupling constants by comparison of the calculated observables with a sufficient number of experimental data. So, we need five observables to obtain LECs. One of the five parity-violating observables is the photon circular polarization ($P_{\gamma}$ in nd $\rightarrow$ ³H$\gamma$ process. We calculate $P_{\gamma}$ at the leading order in terms of LECs. We compare our results with the previous $P_{\gamma}$ calculation based on the model of Desplanques, Donoghue and Holstein.