Measurements of the X c and X b Quarkonium States in pp Collisions with the ATLAS Experiment

Measurements of the X c and X b Quarkonium States in pp Collisions with the ATLAS Experiment
Author: Andrew Chisholm
Publisher: Springer
Total Pages: 193
Release: 2015-09-14
Genre: Science
ISBN: 3319231200
GET BOOK

Download Measurements of the X c and X b Quarkonium States in pp Collisions with the ATLAS Experiment Book in PDF, Epub and Kindle

This thesis, which won one of the six 2015 ATLAS Thesis Awards, concerns the study of the charmonium and bottomonium bound heavy quark bound states. The first section of the thesis describes the observation of a candidate for the chi_b(3P) bottomonium states. This represented the first observation of a new particle at the LHC and its existence was subsequently confirmed by D0 and LHCb experiments. The second part of the thesis presents measurements of the prompt and non-prompt production of the chi_c1 and chi_c2 charmonium states in proton-proton collisions. These measurements are compared to several theoretical predictions and can be used to inform the development of theoretical models of quarkonium production.

Measurements of ZH and WH Production in the H → Bb Decay Channel in Pp Collisions at 13 TeV with the ATLAS Detector

Measurements of ZH and WH Production in the H → Bb Decay Channel in Pp Collisions at 13 TeV with the ATLAS Detector
Author: ATLAS Collaboration CERN
Publisher:
Total Pages:
Release: 2020
Genre:
ISBN:
GET BOOK

Download Measurements of ZH and WH Production in the H → Bb Decay Channel in Pp Collisions at 13 TeV with the ATLAS Detector Book in PDF, Epub and Kindle

Abstract: Measurements are presented of the Standard Model Higgs boson decaying into a bb ̄ pair and produced in association with a W or Z boson decaying into leptons, using proton-proton collision data collected between 2015 and 2018 by the ATLAS detector. The measurements use data delivered by the Large Hadron Collider at a centre-of-mass energy of s√=13 TeV, corresponding to an integrated luminosity of 139 fb−1. The production of a Higgs boson in association with a W or Z boson is established, with observed (expected) significances of 4.0 (4.1) and 5.3 (5.1) standard deviations, respectively. Cross-sections of associated production of a Higgs boson decaying into bottom quark pairs with an electroweak gauge boson, W or Z, decaying into leptons are measured as a function of the gauge boson transverse momentum in kinematic fiducial volumes. The cross-section measurements are all consistent with the Standard Model expectations, and the total uncertainties vary from 30% in the high gauge boson transverse momentum regions to 85% in the low regions

Measurement of Quarkonium Polarization to Probe QCD at the LHC

Measurement of Quarkonium Polarization to Probe QCD at the LHC
Author: Valentin Knünz
Publisher: Springer
Total Pages: 179
Release: 2017-01-07
Genre: Science
ISBN: 3319499351
GET BOOK

Download Measurement of Quarkonium Polarization to Probe QCD at the LHC Book in PDF, Epub and Kindle

This thesis discusses in detail the measurement of the polarizations of all S-wave vector quarkonium states in LHC proton-proton collisions with the CMS detector. Heavy quarkonium states constitute an ideal laboratory to study non-perturbative effects of quantum chromodynamics and to understand how quarks bind into hadrons. The experimental results are interpreted through an original phenomenological approach, which leads to a coherent picture of quarkonium production cross sections and polarizations within a simple model, dominated by one single color-octet production mechanism. These findings provide new insights into the dynamics of heavy quarkonium production at the LHC, an important step towards a satisfactory understanding of hadron formation within the standard model of particle physics.

Measurement of the W Charge Asymmetry in the Pp Collisions at [arrow]"

Measurement of the W Charge Asymmetry in the Pp Collisions at [arrow]
Author:
Publisher:
Total Pages: 19
Release: 2011
Genre:
ISBN:
GET BOOK

Download Measurement of the W Charge Asymmetry in the Pp Collisions at [arrow]" Book in PDF, Epub and Kindle

This letter reports a measurement of the muon charge asymmetry from W Boson produced in proton-proton collisions at a centre-of-mass energy of 7 TeV with the ATLAS experiment at the LHC. The asymmetry is measured in the W → [mu][nu] decay mode as a function of the muon pseudorapidity using a data sample corresponding to a total integrated luminosity of 31 pb-1. The results are compared to predictions based on next-to-leading order calculations with various parton distribution functions. The measurement provides information on the u and d quark momentum fractions in the proton.

A Measurement of the W±Z Production Cross Section and Limits on Anomalous Trilinear Gauge Couplings in Proton-proton Collisions at √s

A Measurement of the W±Z Production Cross Section and Limits on Anomalous Trilinear Gauge Couplings in Proton-proton Collisions at √s
Author: Advait Neel Nagarkar
Publisher:
Total Pages: 73
Release: 2012
Genre:
ISBN:
GET BOOK

Download A Measurement of the W±Z Production Cross Section and Limits on Anomalous Trilinear Gauge Couplings in Proton-proton Collisions at √s Book in PDF, Epub and Kindle

I present a measurement of the W±Z production cross section in the leptonic final states in pp collisions at √s = 7 TeV and limits on anomalous trilinear gauge couplings, using 4.64 fb-1 of data collected using the ATLAS experiment at the LHC. The production cross section has been determined to be 19.0+1.4-1.3(stat.)±0.9(syst.)±0.4(lumi.) pb, in agreement with the Standard Model (SM) expectation of 17.6+1.1-1.0 pb. A search for anomalous trilinear gauge couplings has been conducted and limits have been set at the 95% confidence level; the result is consistent with the SM couplings.