Search for Microscopic Black Holes in Multijet Final States with the ATLAS Detector using 8 TeV Proton-Proton Collisions at the Large Hadron Collider

• Author / Creator

  Saddique, Asif

• Microscopic black holes are expected to produce a high multiplicity of Standard Model (SM) particles having large transverse momenta in the final state. In this thesis, a search for microscopic black holes in multijet final states with the ATLAS 2012 data using 8~TeV centre of mass energy of proton-proton collisions at the Large Hadron Collider is performed in a data sample corresponding to an integrated luminosity of $20.3$ fb$^{-1}$. The search is simplified to multijet final states because most of the expected SM particles produced from black hole decay would lead to hadronic jets. The data events with high-transverse momenta have been analysed for different exclusive jet multiplicities, i.e. $2,3,...,7$, and inclusive jet multiplicities, i.e. $\geq 3,4,...,7$. In this multijet analysis, Quantum Chromodynamics (QCD) multijet production is the main background. For all the multijet final states, the data distributions for the sum of jet transverse momenta ($H{T}=\sum p{T}$) in an event have been observed to be consistent with QCD expectations. For inclusive multijet final states, model-independent and model-dependent exclusion limits at a 95$\%$ confidence level are set on the production of new physics and non-rotating black holes, respectively. The model-independent upper limit on cross section times acceptance times efficiency is 0.29 fb to 0.14 fb for jet multiplicities $\geq3$ to $\geq7$ for $H_{T}>4.0$ TeV. The model-dependent lower limits on minimum black hole mass are set for different non-rotating black hole models.

• Subjects / Keywords

  • Microscopic Black Holes, ATLAS, LHC

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R31Z42062

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.