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

Abstract

We study the parity-violating effects in $nd\to$ ${}^{3}H\gamma$ 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 $nd\to$ ${}^{3}H\gamma$ 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.

Comments: submitted paper