Measurement of the pair production of $b$-jets in proton-proton collisions at $\sqrt{s}$ = 7~TeV with the ATLAS detector

In hadronic collisions, a large amount of processes with large momentum transfer produce a pair of high-$p_{\textrm T}$ jets. Their production rate and event properties can be predicted with good precision using perturbative Quantum Chromodynamics (QCD). The production of bottom-quarks in such collisions is a benchmark process in perturbative QCD because they probe the underlying strong dynamics at a well-defined scale. Because of their large mass, bottom-flavoured particles hold the most direct correspondence between the parton-level production and the observed hadron level. The large pair production rate of bottom-quarks and their corresponding decay products makes them important as background source for many analyses including searches for new physics. Besides this, quarks of the third generation could take an exceptional position among the quarks concerning the sensitivity to new massive objects. Studies on the fraction of jets containing bottom-flavoured particles, known as $b$-jets, relative to all-flavour jets could reveal such new phenomena. In this thesis the production rate of and the correlation between pairs of $b$-jets is measured. The invariant dijet mass spectrum is searched for indications for a new resonance in context of physics beyond the Standard Model. At the Large Hadron Collider (LHC) two proton beams at a centre-of-mass energy of $\sqrt s = 7$~TeV collide, producing a large number of such pairs of $b$-jets. This measurement makes use of the data recorded with the ATLAS detector. The total integrated luminosity available for the analysis is about 34~pb$^{-1}$. $b$-jets are identified via their long lifetime and the reconstruction of their charged decay products. For this analysis differences between jets originating from light objects, like gluons and light quarks, compared to jets containing bottom-flavoured objects have to be taken into account. The jet energy scale of $b$-jets is established and the additional uncertainty on the jet energy measurement is determined. Detector effects in the jet reconstruction special to $b$-jets are studied in order to make the measurement independent of the detector and to correct them to hadron level. Then the cross section measured is compared to next-to-leading order Monte-Carlo predictions. These next-to-leading order predictions are in agreement with ATLAS data. Consequently, the underlying production mechanism is confirmed to also be valid in this new energy regime of the LHC. However, first indications for deviations in the description of next-to-leading processes are discovered. Up to an invariant dijet mass of about 1.7~TeV no evidence for a new resonance decaying into a pair of high-$p_{\textrm T}$ $b$-jets is found. Therefore, model-independent upper limits are calculated for signals following a Gaussian distribution with different signal widths.