Chris Hays

Boosted objects: a probe of beyond the standard model physics

We present the report of the hadronic working group of the BOOST2010 workshop held at the University of Oxford in June 2010. The first part contains a review of the potential of hadronic decays of highly boosted particles as an aid for discovery at the LHC and a discussion of the status of tools developed to meet the challenge of reconstructing and isolating these topologies. In the second part, we present new results comparing the performance of jet grooming techniques and top tagging algorithms on a common set of benchmark channels. We also study the sensitivity of jet substructure observables to the uncertainties in Monte Carlo predictions.

Prospects for new physics in τ→lμμ at current and future colliders.

A bstractThe discovery of lepton flavour violating interactions will be striking evidence for physics beyond the Standard Model. Focusing on the three decays τ∓ → μ±μ∓μ∓, τ∓ → e±μ∓μ∓ and τ∓ → e∓μ∓μ±, we evaluate the discovery potential of current and future high-energy colliders to probe lepton flavour violation in the τ sector. Based on this potential we determine the expected constraints on parameters of new physics in the context of the Type-II Seesaw Model, the Left-Right Symmetric Model, and the Minimal Supersymmetric Standard Model. The existing and ongoing 13 TeV run of the Large Hadron Collider has the potential to produce constraints that outperform the existing e+e− collider limits for the τ∓ → μ±μ∓μ∓ decay and achieve a branching fraction limit of ≲ 10−8. With a future circular e+e− collider, constraints on the τ → lμμ branching fractions could reach as low as a few times 10−12.