Boosting the discovery using τs in the ATLAS detector at the Large Hadron Collider

Almost ten years into the highly successful program both in ATLAS and CMS, our understanding of the Standard Model (SM) of particle physics has deepened. Nonetheless, what lies beyond the SM remains one of the most urgent questions of physics in the 21st century. To move forward, one must think outside of the box and leap into uncharted waters.

Searches today are aiming at the high-energy frontier, while low-mass resonances are mostly overlooked by the Large Hadron Collider (LHC). Consequently, far-reaching hints of new physics may silentlyhide in the data.

Motivated by numerous New Physics (NP) scenarios that often predict light states, such as extended Higgs sectors, axion physics, or dark sector models, among others, the PI will develop new techniques to search for low-mass resonances decaying into two collimated low-pT hadronic τ leptons. τs, being the heaviest, third-generation leptons, provide a unique experimental opportunity to search for low-lying states that would otherwise go undetected.

In particular, novel methods to identify boosted hadronic τ+τ− pairs will be established.

These techniques will then be used to pave a new path towards discovery of low-mass resonances produced through various production modes.

As part of this proposal, the PI will also develop new trigger-level capabilities to further extend the reach of this program at Run-3.

As a former leader of the ATLAS Beyond the Standard Model physics group, and current leader of low-mass resonance searches, the PI is ideally positioned to establish a strong research team and take this project to completion, laying the groundwork for the discovery of new physics beyond the SM.