Sharpening the shape analysis for higher-dimensional operator searches

TL;DR

This paper introduces a systematic method for optimally estimating shape deformations in collider distributions caused by higher-dimensional operators, improving sensitivity in new physics searches.

Contribution

It presents a simple, systematic approach to minimize estimation uncertainty of operator effects in collider simulations, especially addressing interference term challenges.

Findings

Method applied to ${ m O}_{3W}$ operator in $W^+W^-$ production.

Derived bounds on ${ m O}_{3W}$ using 8 TeV CMS data.

Enhanced accuracy in shape deformation estimations.

Abstract

When the Standard Model is interpreted as the renormalizable sector of a low-energy effective theory, the effects of new physics are encoded into a set of higher dimensional operators. These operators potentially deform the shapes of Standard Model differential distributions of final states observable at colliders. We describe a simple and systematic method to obtain optimal estimations of these deformations when using numerical tools, like Monte Carlo simulations. A crucial aspect of this method is minimization of the estimation uncertainty: we demonstrate how the operator coefficients have to be set in the simulations in order to get optimal results. The uncertainty on the interference term turns out to be the most difficult to control and grows very quickly when the interference is suppressed. We exemplify our method by computing the deformations induced by the ${\cal O}_{3W}$ operator in $W^+W^-$ production at the LHC, and by deriving a bound on ${\cal O}_{3W}$ using $8$ TeV CMS data.