This paper presents an outline of the generation of mass for the massive Standard Model particles (fermions, $W^\pm$, $Z^0$) through electroweak symmetry breaking via the Higgs mechanism, and how the Higgs boson emerges from this framework. A Monte Carlo study was done on the decay $H\rightarrow\tau\tau$, with one leptonically and one hadronically decaying tau, with two different production channels for the $H$, gluon-gluon fusion (gg) and vector boson fusion (VBF), at $\sqrt s = 7\tev$ with a Higgs mass $m_H = 120\gev$. The kinematics of these two production channels were compared and it was found that the transverse momentum of muons produced in VBF were higher on average than those produced in gg. This differance was greater in muons originating from the leptonically decaying tau in the Higgs decay, than those produced by other processes in the underlying event. In the latter, however, the difference was still noticable. Jets were slightly more abundant in VBF than in gg, and were in VBF more distributed along the beam axis. The separation in pseudorapidity between the two jets with highest transverse momentum was found to be greater in VBF than in gg. An attempt to reconstruct the Higgs mass using Monte Carlo data run through a simulation of the ATLAS detector was done. The estimator used was the transverse mass of the system consisting of the visible part of the hadronically decaying tau, the lepton from the leptonically decaying tau and the total missing transvese energy. In gg the mean of the transvese mass distribution was found to be $89.26\gev$ with a root mean square uncertainty (RMS) of $23.86\gev$. In VBF the mean was found to be $85.57\gev$ with RMS $27.08\gev$.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-239238 |
| Date | January 2014 |
| Creators | Isacson, Max |
| Publisher | Uppsala universitet, Högenergifysik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | FYSAST ; FYSKAND1026 |
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