Potential of di-Higgs observation via a calibratable jet-free $HH\to 4b$ framework

TL;DR

This paper introduces a novel jet-free framework that significantly improves the detection sensitivity of the Higgs pair production channel $HH o 4b$ at the LHC, enabling more precise measurements of the Higgs self-coupling.

Contribution

The paper presents a calibratable, jet-free analysis method using mass-decorrelated discriminants and multiclass classification, enhancing $HH$ detection sensitivity beyond existing approaches.

Findings

Over fivefold increase in search significance compared to previous methods

Calibration of $HH$ signal response using $ZZ o 4b$ process

Potential for $HH$ observation with current LHC data, constraining $$ within HL-LHC projections.

Abstract

We present a calibratable, jet-free framework that enhances the search significance of the flagship LHC channel $HH \to 4b$ by more than a factor of five compared to existing approaches. The method employs a mass-decorrelated discriminant to identify $h_1 h_2 \to 4b$ with variable $h_{1,2}$ masses and a simultaneous estimator of $(m_{h_1}, m_{h_2})$, both derived from multiclass classification on all-particle inputs. The $HH$ signal response can be calibrated using $ZZ \to 4b$. Using a highly realistic simulation framework validated through multiple tests, we demonstrate the method's robustness and identify two prerequisites essential for achieving this level of sensitivity. Results indicate that with LHC Run 2 and 3 data, observation-level sensitivity to $HH$ appears within reach, enabling constraints on $\kappa_\lambda$ comparable to HL-LHC projections and offering an accelerated path to precision measurements of the Higgs trilinear coupling.