# Search for non-resonant Higgs boson pair production in the $bb\ell\nu\ell\nu$ final state with the ATLAS detector in $pp$ collisions at $\sqrt{s} = 13$ TeV

## TL;DR

This paper reports a search for non-resonant Higgs boson pair production in the $bb\,\ell\nu\ell\nu$ final state using ATLAS data, setting upper limits on the production cross-section relative to the Standard Model prediction.

## Contribution

It introduces a neural network-based discriminant to identify Higgs pair production events in the $bb\,\

## Key findings

- Set an upper limit of 1.2 pb on the production cross-section.
- Observed data is consistent with the Standard Model within uncertainties.
- The analysis improves sensitivity using machine learning techniques.

## Abstract

A search for non-resonant Higgs boson pair production, as predicted by the Standard Model, is presented, where one of the Higgs bosons decays via the $H\rightarrow bb$ channel and the other via one of the $H \rightarrow WW^*/ZZ^*/\tau\tau$ channels. The analysis selection requires events to have at least two $b$-tagged jets and exactly two leptons (electrons or muons) with opposite electric charge in the final state. Candidate events consistent with Higgs boson pair production are selected using a multi-class neural network discriminant. The analysis uses 139 fb$^{-1}$ of $pp$ collision data recorded at a centre-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. An observed (expected) upper limit of 1.2 ($0.9^{+0.4}_{-0.3}$) pb is set on the non-resonant Higgs boson pair production cross-section at 95% confidence level, which is equivalent to 40 ($29^{+14}_{-9}$) times the value predicted in the Standard Model.