Journal Article

EFT at FASERν

Tabrizi, Zahra, Kopp, Joachim, Soreq, Yotam, Falkowski, Adam, González-Alonso, Martín

2021

Overview

A bstract We investigate the sensitivity of the FASER ν detector to new physics in the form of non-standard neutrino interactions. FASER ν , which will be installed 480 m downstream of the ATLAS interaction point, will for the first time study interactions of multi-TeV neutrinos from a controlled source. Our formalism — which is applicable to any current and future neutrino experiment — is based on the Standard Model Effective Theory (SMEFT) and its counterpart, Weak Effective Field Theory (WEFT), below the electroweak scale. Starting from the WEFT Lagrangian, we compute the coefficients that modify neutrino production in meson decays and detection via deep-inelastic scattering, and we express the new physics effects in terms of modified flavor transition probabilities. For some coupling structures, we find that FASER ν will be able to constrain interactions that are two to three orders of magnitude weaker than Standard Model weak interactions, implying that the experiment will be indirectly probing new physics at the multi-TeV scale. In some cases, FASER ν constraints will become comparable to existing limits — some of them derived for the first time in this paper — already with 150 fb − 1 of data.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V,Springer,Springer Nature,SpringerOpen
• Subject: Classical and Quantum Gravitation / CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS / Effective Field Theories / Elementary Particles / Field theory / Flavor (particle physics) / High energy physics / High Energy Physics - Experiment / High Energy Physics - Phenomenology / Inelastic scattering / Neutrino Physics / Neutrinos / Particle decay / Physics / Physics and Astronomy / Quantum Field Theories / Quantum Field Theory / Quantum Physics / Regular Article - Theoretical Physics / Relativity Theory / Standard model (particle physics) / String Theory / Transition probabilities