Photon asymmetries in $nd\rightarrow$ $^3H\gamma$ using EFT($\pi/!/!/!/$) approach

TL;DR

This paper uses pionless effective field theory to calculate parity-violating observables in neutron-deuteron radiative capture, matching low-energy constants to DDH estimates and comparing results with experimental data and prior models.

Contribution

It provides a novel EFT($ ot\pi$) framework calculation of parity-violating photon asymmetries in $nd ightarrow{}^3H\gamma$, linking LECs to DDH estimates and experimental results.

Findings

Calculated photon asymmetries $a^{nd}_\gamma$ and $A^{nd}_\gamma$ in $nd ightarrow{}^3H\gamma$.

Matched EFT LECs to DDH best estimates for parity violation.

Compared EFT results with experimental data and previous DDH-based calculations.

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.