Study of Muons Associated with Jets in Proton-antiproton Collisions at Sqrt.s

Study of Muons Associated with Jets in Proton-antiproton Collisions at Sqrt.s
Author: David Austen Smith
Publisher:
Total Pages:
Release: 1989
Genre:
ISBN:

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Production of heavy quark flavors in proton-antiproton collisions with a center-of-mass energy of 1.8 $\times$ 10$\sp{12}$ electron volts is studied for events containing hadronic jets with a nearby muon track, where both the jet and the muon are produced at large angles from the incident beams. The muon tracking system and pattern recognition are described. Detailed calculations of the muon background due to meson decay and hadron noninteractive punchthrough are presented, and other background sources are evaluated. Distributions of muon transverse momentum relative to the beam and the jet axis agree with QCD expectations for semileptonic charm and beauty decay. Muon identification cuts and background subtraction leave 57.5 $\pm$ 17.1 muon-jet pairs, a rate consistent with the established production cross sections for charm and beauty quarks and the acceptance for minimum ionizing particles overlapping with nearby jets. A small dimuon sample clarifies the muon signature. No signatures of undiscovered phenomena are observed in this new energy domain.

Study of Double Parton Scattering Using Four-Jet Scenarios

Study of Double Parton Scattering Using Four-Jet Scenarios
Author: Paolo Gunnellini
Publisher: Springer
Total Pages: 290
Release: 2015-08-24
Genre: Science
ISBN: 3319222139

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This thesis addresses in a very new and elegant way several measurements and the extraction of so-called double parton scattering. The new and elegant way lies in the combination of measurements and a very smart extraction of double parton scattering results, which is easy to apply and overcomes many of the technical difficulties of older methods. Many new phenomena in particle physics can be observed when particles are collided at the highest energies; one of the highlights in recent years was the discovery of the Higgs boson at the Large Hadron Collider at CERN. Understanding the production mechanism of the Higgs boson at the LHC requires detailed knowledge of the physics of proton-proton collisions. When the density of partons in the protons becomes large, there is a non-negligible probability that more than one parton participates in the interaction and the so-called double parton scattering becomes important. In some cases very particular final state signatures can be observed, which can be regarded as an indication of such double partonic scattering and where the different interactions can be separated. Such multiple partonic interactions play an important role when precise predictions from known processes are required.