Big Dipper, Help Me Find A Way -- Dip-hunting at hadron colliders

TL;DR

This paper introduces a neural network-based method to identify potential BSM scalar signals at hadron colliders by analyzing interference patterns, extending traditional bump-hunting techniques.

Contribution

It develops a parametric neural network framework to infer BSM scalar parameters from observed interference patterns, enabling a new diagnostic approach called 'dip-hunting'.

Findings

Neural networks can learn likelihood ratios for BSM signals with interference effects.

The approach provides a robust diagnostic tool in perturbative regimes.

Dip-hunting extends traditional bump-hunting strategies for future discoveries.

Abstract

Destructive interference between signal and background processes poses a fundamental challenge in searches for top-philic scalar resonances, significantly reducing experimental sensitivity to well-motivated extensions of the Higgs sector. Traditional bump-hunting strategies fail in this instance because interference effects invalidate the narrow-width approximation across large regions of the BSM parameter space. As a result, experimental analyses typically rely on detailed simulations to accurately model these effects throughout the full analysis chain. In this work, we consider the inverse problem in a proof-of-principle study: given an observed pattern in a discriminating distribution, what is the likelihood that it originates from a BSM scalar? To address this, we employ parametric neural networks to learn the likelihood ratio as a function of both background and key BSM parameters, based on a ratio-of-signed-mixtures framework. We perform inference by testing the compatibility of observed data with a scan over the parameter space of a minimal scalar extension of the Standard Model. While BSM parameter extraction remains inherently model-dependent, our approach provides a robust diagnostic in perturbative regimes and motivates a complementary strategy of `dip-hunting'. This strategy extends traditional bump-hunts and could point the way as we navigate towards future discoveries.