A study on invariant mass reconstruction techniques for a boosted tau pair, in the context of boosted Higgs pair searches in the b¯bτhadτhad channel at the LHC with the ATLAS detector

Abstract

The LHC has proven to be one of the most ambitious and powerful particle colliders to date, being capable to explore the TeV energy scale and to produce a particle compatible with the Higgs boson, such discovery was confirmed in 2012 by the CMS and ATLAS experiments. While exploring possibilities for physics beyond the Standard Model, the ATLAS collaboration further searches for heavy resonances decaying into a Higgs boson pair. The understanding of the final states involving the decays of a pair of Higgs bosons are crucial channels in the search of heavy resonances, which are predicted by theories encompassed in minimal supersymmetric Standard Model extensions or other theories beyond the Standard Model. A pair of highly collimated tau leptons in the final state challenges the reconstruction of Higgs particles due to the partial overlap of the hadronic tau jets in the detector. Particularly, in this work, we studied the boosted topology of the decay chain X → hh → b¯bτ+τ− in a fully hadronic final state, implementing a reconstruction technique for the invariant mass of a boosted tau pair, applying the collinear mass approximation method and compare the results with the visible decay system.