Search for Higgs boson pair production in the b[bar over b]b[bar over b] final state from pp collisions at √s = 8 TeV the ATLAS detector

Abstract

A search for Higgs boson pair production pp→hh is performed with 19.5 fb [superscipt −1] of proton–proton collision data at √s=8 TeV, which were recorded by the ATLAS detector at the Large Hadron Collider in 2012. The decay products of each Higgs boson are reconstructed as a high-momentum b[bar over b]b[bar over b] system with either a pair of small-radius jets or a single large-radius jet, the latter exploiting jet substructure techniques and associated b-tagged track-jets. No evidence for resonant or non-resonant Higgs boson pair production is observed. The data are interpreted in the context of the Randall–Sundrum model with a warped extra dimension as well as the two-Higgs-doublet model. An upper limit on the cross-section for pp→G[subscript ∗KK]→hh→b[bar overb]b[bar overb] of 3.2 (2.3) fb is set for a Kaluza–Klein graviton G[subscript ∗KK] mass of 1.0 (1.5) TeV, at the 95 % confidence level. The search for non-resonant Standard Model hh production sets an observed 95 % confidence level upper limit on the production cross-section σ(pp→hh→b[bar over b]b[bar over b]) of 202 fb, compared to a Standard Model prediction of σ(pp→hh→b[bar over b]b[bar over b])=3.6±0.5.