# ttbb as a probe of New Physics at the LHC

## TL;DR

This paper investigates the $tar t b ar b$ final state at the LHC as a sensitive probe for new physics models coupling predominantly to third-generation quarks, analyzing various resonance spins and proposing improved observables.

## Contribution

It introduces a new observable to reduce Monte Carlo dependence and explores unexcluded parameter space for new physics models using LHC data.

## Key findings

- Identifies parameter regions where $t\bar t b\bar b$ is most sensitive
- Proposes an observable that minimizes Monte Carlo reliance
- Provides preliminary discovery estimates at 13 TeV

## Abstract

We study the $t\bar t b \bar b$ final state at the LHC as a probe of New Physics that couples mainly to third generation of quarks. We analyze New Physics simplified models with resonances of spin 0, 1 and 2. The sensitivity of the final states $t\bar t b\bar b$, $t\bar t t \bar t$, $b \bar b b \bar b$ and $t \bar t$ on each of these models is used to identify an important region in parameter space that is still not excluded and where $t\bar t b \bar b$ is the most sensitive final state. We indicate possible experimental hints and discuss potential issues of observables that rely mainly in Montecarlo predictions. A new observable is proposed that, at the price of requiring more statistics, reduces the impact of Montecarlo predictions. We use preliminary 13 TeV results to give a raw estimate on the discovery reach and propose simple improvements on the observables.