This thesis presents details of the search for the Standard Model Higgs boson, in
the low mass region (100 ≤ MH < 150 GeV), with the ATLAS detector at CERN.
In this range, a Higgs boson may be produced in association with a W or Z-boson
and decay predominantly to two b-quarks (H → b¯b). Specifically events having
large Higgs boson transverse momentum (pT > 200 GeV) and large recoiling W-
boson transverse momentum (pT > 200 GeV) are considered as a means to reduce
the contribution from background processes. In this high pT (boosted) regime,
novel jet-substructure techniques are applied to the reconstructed jets resulting
from the Higgs boson decay. In order to use these jet-substructure techniques,
b-tagging efficiency scale factors in the jet-substructure regime have also been
derived for the first time. Details of their derivation are presented for many b-
tagging algorithms, with 14.3 fb¯¹ of ATLAS proton-proton collision data in 2012
at √s = 8 TeV. These, and their associated systematic uncertainties, are then
applied to the Higgs boson search. No significant measurement of Higgs boson
production was made, based on 20.4 fb¯¹ of ATLAS proton-proton collision data
in 2012 at √s = 8 TeV. For a Higgs boson mass of 125 GeV, an exclusion
limit of 6.12 x σSM was found at the 95% confidence level, and a signal strength
of 0:93 ± 2:63 was measured, consistent with both background-only and signal
(Standard Model Higgs boson) plus background hypotheses