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

We study the parity-violating effects in $nd\rightarrow$ $^3Hγ$ 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 ($P_γ$) in $nd\rightarrow$ $^3Hγ$ process. We calculate $P_γ$ at the leading order in terms of LECs. We compare our results with the previous $P_γ$ calculation based on the model of Desplanques, Donoghue, and Holstein.