Search for anomalous Higgs boson production in association with single top quarks using the CMS detector
(2015)
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- Authors
- Supervisors
- Giammanco, Andrea
- Abstract
- This thesis describes a search for production of a Higgs boson in association with a single top quark, conducted in the CMS experiment at the CERN Large Hadron Collider (LHC). This process offers a unique way to study certain aspects of the interaction between the Higgs boson and the top quark. The search targets the anomalous case of a negative top quark Yukawa coupling constant, which leads to a significant enhancement of the tH production cross section with respect to the expectation in the standard model. The study exploits data collected in proton-proton collisions at a centre-of-mass energy of 8 TeV, corresponding an accumulated luminosity of about 20/fb. In the considered final state the top quark decays producing a muon or an electron, and the Higgs boson decays into a pair of b quarks. The event selection takes advantage of multiple b-quark jets as well as a jet in the forward region in pseudorapidity. The selected sample of events is largely dominated by the top quark pair production, and artificial neural networks are applied in order to identify signal-like events. A special attention is given to construction of input variables in the multijet final state. Observed data are found to be compatible with the background-only expectation, and an upper limit on the tH production cross section is set. The observed limit at the 95% confidence level is 1.8 pb, which exceeds the expected cross section of the anomalous tH production by a factor of 7.6. Data that will be collected by the LHC in the years to come will allow to rule out (or discover) the considered anomalous tH production.
- Affiliations
UCLouvain SST/IRMP - Institut de recherche en mathématique et physique
Citations
Popov, A. (2015). Search for anomalous Higgs boson production in association with single top quarks using the CMS detector. https://hdl.handle.net/2078.5/188952