Monolepton production in SMEFT to $\mathcal{O}(1/{\Lambda }^4)$ and beyond

Abstract

We calculate $pp\to {\ell }^{+}\nu ,{\ell }^{-}\bar{\nu }$ to $\mathcal{O}(1/{\Lambda }^4)$ within the Standard Model Effective Field Theory (SMEFT) framework. In particular, we calculate the four-fermion contribution from dimension six and eight operators, which dominates at large center of mass energy. We explore the relative size of the $\mathcal{O}(1/{\Lambda }^4)$ and $\mathcal{O}(1/{\Lambda }^2)$ results for various kinematic regimes and assumptions about the Wilson coefficients. Results for Drell-Yan production $pp\to {\ell }^{+}{\ell }^{-}$ at $\mathcal{O}(1/{\Lambda }^4)$ are also provided. Additionally, we develop the form for four fermion contact term contributions to $pp\to {\ell }^{+}\nu ,{\ell }^{-}\bar{\nu },pp\to {\ell }^{+}{\ell }^{-}$ of arbitrary mass dimension. This allows us to estimate the effects from even higher dimensional (dimension $>8$) terms in the SMEFT framework.