| dc.contributor.advisor | Quadt, Arnulf Prof. Dr. | |
| dc.contributor.author | Drechsler, Eric | |
| dc.date.accessioned | 2019-01-04T11:25:36Z | |
| dc.date.available | 2019-01-04T11:25:36Z | |
| dc.date.issued | 2019-01-04 | |
| dc.identifier.uri | http://hdl.handle.net/11858/00-1735-0000-002E-E54A-6 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-7194 | |
| dc.language.iso | eng | de |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | |
| dc.subject.ddc | 530 | de |
| dc.title | Measurement of the Higgs Boson Production Cross Section in Hadronic Final States in 13 TeV Proton-Proton Collisions with the ATLAS Detector | de |
| dc.type | doctoralThesis | de |
| dc.contributor.referee | Blumenschein, Ulrike Dr. | |
| dc.date.examination | 2018-03-14 | |
| dc.subject.gok | Physik (PPN621336750) | de |
| dc.description.abstracteng | The couplings of the Standard Model Higgs boson to fermions provide valuable insights into the nature of electroweak symmetry breaking in the Yukawa sector.
This thesis summarises the measurement of the Higgs boson production cross section in decays to two hadronically decaying -leptons. The measurement is based on 36.1 fb⁻¹ proton-proton collision data at a centre-of-mass energy of 13 TeV recorded in 2015 and 2016 with the Atlas detector at the Large Hadron Collider.
A cut-based and a multivariate analysis approach are investigated, based on the reconstructed mass and boosted decision trees, respectively. The two dominant Higgs
boson production modes, the gluon-gluon fusion and vector-boson fusion, are targeted for a mass hypothesis of mH = 125 GeV. Their characteristic event topologies are exploited to
separate Higgs decays from background processes.
The main background sources arise from Drell-Yan and multijet events. The background
estimation relies on both simulation and data-driven methods.
An excess of events over the predicted background was found, corresponding to an
observed (expected) significance of 4.15 (3.56) standard deviations for the multivariate
analysis. The signal strength for the multivariate analysis was measured as μ = 1.15±0.39
and is compatible within total uncertainties with the cut-based result of μ = 0.73 ± 0.34.
The measured total cross section times branching ratio for the H(tt) had had process
is CBA = 1.06 ± 0.49 pb for the cut-based analysis and MVA = 1.67 ± 0.57 pb for the
multivariate approach, quoted with the respective total uncertainty.
This result constitutes a direct evidence of the Higgs boson couplings to fermions and
confirms the Standard Model prediction for a Higgs boson mass of mH = 125 GeV. | de |
| dc.contributor.coReferee | Zinonas, Zinonos Dr. | |
| dc.contributor.thirdReferee | Lai, Stan Prof. Dr. | |
| dc.subject.eng | Higgs | de |
| dc.subject.eng | Boson | de |
| dc.subject.eng | Particle Physics | de |
| dc.subject.eng | Tau Decays | de |
| dc.subject.eng | ATLAS | de |
| dc.subject.eng | LHC | de |
| dc.subject.eng | Run II | de |
| dc.subject.eng | BDT | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-11858/00-1735-0000-002E-E54A-6-4 | |
| dc.affiliation.institute | Fakultät für Physik | de |
| dc.identifier.ppn | 1045680974 | |