Searching for new physics from SMEFT and leptoquarks at the P2 experiment

TL;DR

The P2 experiment's high-precision measurements can significantly improve constraints on new physics models like SMEFT and leptoquarks, surpassing current limits and resolving existing experimental tensions.

Contribution

This paper evaluates P2's sensitivity to SMEFT operators and leptoquarks, providing expected limits that extend to energy scales up to 15 TeV and demonstrating potential to resolve degeneracies and tensions.

Findings

P2 can test energy scales up to 15 TeV for SMEFT and leptoquarks.

P2 limits often exceed current LHC and APV constraints.

P2 can help resolve tensions in the weak charge of $^{133}$Cs.

Abstract

The P2 experiment aims at high-precision measurements of the parity-violating asymmetry in elastic electron-proton and electron-$^{12}$C scatterings with longitudinally polarized electrons. We discuss here the sensitivity of P2 to leptoquarks, which within the P2 energy range can be described in the language of Standard Model Effective Field Theory (SMEFT). We give the expected P2 limits on the SMEFT operators and on the leptoquark parameters, which will test energy scales up to 15 TeV. In many cases those limits exceed current constraints from LHC and atomic parity violation (APV) experiments. We also demonstrate that degeneracies of different SMEFT operators can partially be resolved by use of APV experiments and different targets (protons and $^{12}$C) at P2. Moreover, we show that P2 could confirm or resolve potential tensions between the theoretical and experimental determinations of the weak charge of $^{133}$Cs.