## Physics & Astronomy ETDs

7-12-2014

#### Abstract

This work involves an analysis of data recorded at the Large Hadron Collider combined with a program to develop detectors for future collider experiments. Using the full 4.9 fb$^{-1}$ of 7 TeV data collected in 2011 and the 19.2 fb$^{-1}$ of 8 TeV data collected in 2012, the $B_c(2S)$ meson has been observed with the ATLAS detector in the hadronic decay mode $B_c(2S)\rightarrow B_c\pi^{+}\pi^{-}$, $B_c\rightarrow J/\psi\pi$. This new state has been found in the mass difference distribution with invariant mass $6845 \pm 7_{stat.} \pm 4_{syst.}$ \MeV. To prepare for the high radiation environment at the High Luminosity LHC, diamond sensors are being developed. Their leakage current and resistivity are measured at fluences and temperatures relevant to the ATLAS upgrade. No evidence of dependence of the resistivity on fluence or temperature has been observed for the ranges [-10 $^\circ$C, +20 $^\circ$C] and [0, $1.0\ imes10^{16} \rm{n_{eq}/cm^2}$]. To study the radiation damage of the sensors in the ATLAS Pixel Detector, their leakage current is monitored at the level of single pixel modules. The result agrees with a prediction based on the Hamburg model.

Physics

Doctoral

#### Department Name

Physics & Astronomy

Seidel, Sally

Seidel, Sally

Errede, Steven

Gorelov, Igor

#### Fourth Committee Member

Allahverdi, Rouzbeh

English

#### Keywords

LHC, ATLAS, Bc meson, Diamond sensor, Pixel detector

Dissertation

COinS