Speaker
John Alison
(University of Chicago (US))
Description
The discovery of a Higgs boson at the Large Hadron Collider motivates an
enhanced effort to search for new physics via the Higgs sector. Many new
physics models predict rates of Higgs boson pair production significantly
higher than the SM rate.
TeV-scale resonances such as the first Kaluza-Klein excitation of the
graviton predicted in the bulk Randall-Sundrum model or a heavy neutral
scalar of two-Higgs-doublet models can decay into pairs of Higgs bosons.
Enhanced non-resonant pp->hh production can also arise in models such as
those with new, light, coloured scalars or direct $t\bar{t}hh$ vertices.
This poster presents an analysis based on the Run 2 ATLAS search in the 4b
final state which set limits on both resonant and non-resonant Higgs boson
pair production.
Two complementary Higgs boson reconstruction techniques are employed. The
first---``resolved''---technique reconstructs Higgs boson candidates from
pairs of nearby anti-kt jets with radius parameter R = 0.4, each b-tagged
with a multivariate b-tagging algorithm. This resolved technique offers
good efficiency over a wide range of Higgs boson momenta and so can be used
to reconstruct di-Higgs-boson resonances with mass up to 1200~\GeV.
At higher masses the anti-kt R-0.4 jets begin to merge, motivating the use
of a second---``boosted''---Higgs boson reconstruction technique that
maintains acceptance for these higher-mass resonances through the use of
large radius jets and jet substructure techniques. In boosted regime, the
Higgs boson candidate is reconstructed as a single, trimmed anti-kt R=1.0
jet which must have two associated b-tagged anti-kt R = 0.2 track-jets.
This poster presents the first run-2 results and lessons learned.
Author
Collaboration ATLAS
(ATLAS)
