This website requires JavaScript.

# Electroweak box diagrams on the lattice for pion and neutron decay

Dec 2022

CKM matrix is unitary by construction in the standard model(SM). The recentanalyses on the first row of CKM matrix show $\approx 3\sigma$ tension withunitarity. Nonperturbative calculations of the radiative corrections can reducethe theory uncertainty in CKM matrix elements. Here we compute the electroweakbox contribution to the pion and kaon $\beta$ decays using seven $N_f=2+1+1$HISQ-Clover lattice with various pion mass and lattice spacing. The continuumand chiral limit is taken using the leading dependence on $M_\pi$ and $a$,where $M_\pi$ extrapolation is taken to the physical pion mass and $SU(3)$symmetric mass for pion and kaon box contribution, respectively. Our resultsare $\square_{\gamma W}^{VA} |_{\pi} = 2.820 (28) \times 10^{-3}$ and $\square_{\gamma W}^{VA} |_{K} = 2.384 (17) \times 10^{-3}$.

Q1论文试图解决什么问题？
Q2这是否是一个新的问题？
Q3这篇文章要验证一个什么科学假设？
0