Search for the Higgs Boson in the Vector Boson Fusion Channel at the ATLAS Detector

The search for the Higgs boson has been a cornerstone of the physics program at the Large Hadron Collider in Geneva Switzerland. The ATLAS experiment successfully discovered the Higgs using the so-called "Golden Channels" of $H^0\rightarrow\gamma\gamma$ and $H^0\rightarrow ZZ^{(*)}$ using data samples collected during the 2011 and 2012 run periods. In order to check if the discovered Higgs is consistent with purely Standard Model behaviour, it is necessary to further confirm the existence of the Higgs in each production mode and decay channel predicted by the Standard Model. For this dissertation, a search for the Higgs was conducted using the $H^0\rightarrow b\bar{b}$ decay channel, where the Higgs is produced by the inverse pair decay of two weak bosons exchanged by a scattered quark pair, also known as Vector Boson Fusion (VBF). This analysis uses data samples collected during the 2011 run period by the ATLAS detector totalling 4.2 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}=7\;\text{TeV}$. No excess of events above background expectation is observed and 95\% confidence level upper limits on the Standard Model Higgs cross section times branching ratio, $\sigma(VBF)\times\text{BR}(H^0\rightarrow b\bar{b})$, are derived for Higgs masses in the range $115<m_H<130\;\text{GeV}$. An observed 95\% confidence level upper limit of 18.7 times the Standard Model cross section is obtained for a Higgs boson mass of 125 GeV.