Würzburg 2018 – scientific programme

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T: Fachverband Teilchenphysik

T 33: Higgs II

T 33.3: Talk

Tuesday, March 20, 2018, 17:00–17:15, Z6 - HS 0.004

Higgs tagging calibration in g→ bb events with the ATLAS experiment — •Ruth Jacobs, Tatjana Lenz, and Norbert Wermes — Physikalisches Institut, Universität Bonn

The most likely decay of the SM Higgs boson is into two b-quarks. A recent result from the ATLAS collaboration showed evidence for the H→ bb decay in the vector boson associated production mode. To access other production modes, such as gluon gluon fusion, in connection with the H→ bb decay, it is useful to consider Higgs bosons with a large transverse momentum, as the relative background contribution is reduced in this kinematic regime. Other possible sources for these so-called boosted Higgs bosons are decays of heavy resonances, predicted by theories beyond the SM.
In the case of a boosted H→ bb decay, the b-quark fragmentation products are reconstructed using a single large-R jet. A Higgs boson identification algorithm ("Higgs tagging") can be used to decide whether a jet originated from a Higgs boson decay, based on the large-R jet properties. Since the Higgs tagging algorithm is optimized on simulated events, it is important to study whether the large-R jet properties are well described in the simulation. One possibility is to use data events of gluons splitting into b-quark pairs, which are available in sufficient amount at the LHC, compared to Z→ bb or H→ bb. The g→ bb data sample is used to validate the modelling of different large-R jet properties in Monte Carlo simulation. It can also be used to derive a data-based calibration for a Higgs tagging algorithm in close-by b-jet events.