Measurement of Associated Z+charm Production and Search for W' Bosons in the CMS Experimented at the LHC
Measurement of Associated Z+charm Production and Search for W' Bosons in the CMS Experimented at the LHC

Author: Alberto Escalante del Valle

Publisher:

Published: 2017

Total Pages:

ISBN-13:

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Do we understand how elementary particles interact with each other? Are we able to predict the result of the collisions of these elementary particles at the LHC? The objective of this thesis is to investigate the validity of our current theoretical model, the Standard Model of particle physics, to explain the production of two low rate processes in proton-proton collisions at the LHC. The rst half of the thesis studies the potential production of new types of interactions, mediated by new W0 bosons, present in many extensions of the Standard Model. This is the rst search of this kind at a centre of mass energy of 13 TeV in CMS and uses a dataset of 2.3 fb{u100000}1 to search for an excess in the production of events with a muon and large missing transverse energy. As a result of this study, the analysed data is found to be in agreement with predictions of the Standard Model and disfavours the production of new W0 ! processes. This analysis alone is not able to exclude the production of all kind of W0 interactions. However, it puts strong constrains to its potential cross section and decay to a muon and a neutrino, W0B(W0 ! )

Associated Production of W+ Charm in 13 TeV Proton-proton Collisions Measured with CMS and Determination of the Strange Quark Content of the Proton
Associated Production of W+ Charm in 13 TeV Proton-proton Collisions Measured with CMS and Determination of the Strange Quark Content of the Proton

Author: Svenja Karen Pflitsch

Publisher:

Published: 2020

Total Pages: 148

ISBN-13: 9783030527631

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The associated production of a W boson and a single charm quark (W+c) is the only process in proton-proton collisions that directly probes the strange quark content of the proton. In this thesis, W+charm production is measured in proton-proton collisions at the LHC at 13 TeV, as recorded by the Compact Muon Solenoid (CMS) experiment. The analysis focuses on the identification of W bosons in their leptonic decay to a muon and a neutrino and charm quarks are tagged via the full reconstruction of D*-Mesons. The measured cross sections of W+c production are used, in combination with other relevant CMS results and the most precise HERA DIS data, in a QCD analysis to determine the strange quark content of the proton. The resulting strange quark distribution and suppression, with respect to the other light sea quarks, are in good agreement with those obtained in neutrino scattering experiments and extend their kinematic reach.

Measurement of Associated W + Charm Production in Pp Collisions at $\sqrt{s}$
Measurement of Associated W + Charm Production in Pp Collisions at $\sqrt{s}$

Author:

Publisher:

Published: 2014

Total Pages: 63

ISBN-13:

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Measurements are presented of the associated production of a W boson and a charm-quark jet (W + c) in pp collisions at a center-of-mass energy of 7 TeV. The analysis is conducted with a data sample corresponding to a total integrated luminosity of 5 inverse femtobarns, collected by the CMS detector at the LHC. W boson candidates are identified by their decay into a charged lepton (muon or electron) and a neutrino. The W + c measurements are performed for charm-quark jets in the kinematic region $p_T^{jet} \gt$ 25 GeV, $

W and Z Bosons at the LHC
W and Z Bosons at the LHC

Author: Ann-Karin Sanchez

Publisher: Sudwestdeutscher Verlag Fur Hochschulschriften AG

Published: 2013-01

Total Pages: 184

ISBN-13: 9783838136226

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Processes involving W and Z bosons decaying leptonically are among the best understood at hadron colliders. This and their copious production allow for a wide range of studies. The study of hard-diffractive event observables, such as a large rapidity gap in W or Z boson events, is strongly influenced by the underlying multiparton interactions. At present, the description of these processes relies largely on the generator specific tuning of data. Therefore, the measurement and extensive study of such events can be used in the understanding and implementation of detailed simulations of diffraction. Moreover, the measurements of single pomeron exchange are sensitive to the structure of the pomeron and the dynamics of diffraction. A detailed overview towards the observation of a diffractive signal with improvements of Monte Carlo simulations containing multiparton interactions is given. Finally, a precise measurement of the W and Z transverse momenta is presented. The distributions can potentially be used to constrain the gluon distribution function to high precision at LHC energies.

Measurement of Associated Z Boson and Charm Quark Production in Proton-proton Collisions at Square Root of S Equals to 13 TeV
Measurement of Associated Z Boson and Charm Quark Production in Proton-proton Collisions at Square Root of S Equals to 13 TeV

Author: Luis Pinto Cabrera

Publisher:

Published: 2020

Total Pages:

ISBN-13:

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"This thesis presents the measurements of the differential production cross-sections of a Z boson in association with at least one charm-quark-initiated jet, where the Z boson decays leptonically into a muon-antimuon pair. Data recorded in proton-proton collisions by the ATLAS detector at the Large Hadron Collider (LHC) during the years of 2015 to 2018 is utilised, when the LHC was running at a center of mass energy of 13 TeV. The studied data corresponds to a total integrated luminosity of 139 fb^-1. The measurements are compared to simulated data produced at next-to-leading-order and normalized to theoretical predictions at next-to-next-leading order. The results show that predictions underestimate the total number of events by 50% but display a good modelling of all distribution shapes of the chosen observables in data. The discrepancy can be attributed to a problem in the normalisation but further studies need to be made to settle the issue"--

Particle Physics Reference Library
Particle Physics Reference Library

Author: Herwig Schopper

Publisher: Springer Nature

Published: 2020

Total Pages: 632

ISBN-13: 3030382079

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This first open access volume of the handbook series contains articles on the standard model of particle physics, both from the theoretical and experimental perspective. It also covers related topics, such as heavy-ion physics, neutrino physics and searches for new physics beyond the standard model. A joint CERN-Springer initiative, the "Particle Physics Reference Library" provides revised and updated contributions based on previously published material in the well-known Landolt-Boernstein series on particle physics, accelerators and detectors (volumes 21A, B1,B2,C), which took stock of the field approximately one decade ago. Central to this new initiative is publication under full open access

First Differential Measurements of tZq Production and Luminosity Determination Using Z Boson Rates at the LHC
First Differential Measurements of tZq Production and Luminosity Determination Using Z Boson Rates at the LHC

Author: David Walter

Publisher: Springer

Published: 2024-03-05

Total Pages: 0

ISBN-13: 9783031509308

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This thesis describes two groundbreaking measurements in the precision frontier at the LHC: the first ever differential measurement of the Z-associated single top quark (tZq) production, and the luminosity measurement using Z boson production rate for the first time in CMS. Observed only in 2018, the tZq process is of great importance in probing top quark electroweak couplings. These couplings are natural places for new phenomena to happen in the top quark sector of the standard model. Yet, they are the least explored directly. One has to obtain a firm understanding of the modeling of sensitive distributions to new top-Z interactions. The present analysis marks a major milestone in this long-term effort. All distributions relevant for new phenomena, and/or modeling of tZq, are studied in full depth using advanced Machine Learning techniques.The luminosity and its uncertainty contributes to every physics result of the experiment. The method minutely developed in this thesis provides a complementary measurement that results in a significant overall reduction of uncertainties.

A Measurement of Z([small Nu] [small N̄ū])[small Gamma] Production and a Search for New Physics in Monophoton Events Using the CMS Detector at the LHC
A Measurement of Z([small Nu] [small N̄ū])[small Gamma] Production and a Search for New Physics in Monophoton Events Using the CMS Detector at the LHC

Author: James Joseph Buchanan

Publisher:

Published: 2019

Total Pages: 0

ISBN-13:

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This thesis presents several studies of monophoton final states using 35.9 fb^-1 of 13 TeV proton-proton collision data collected by the CMS experiment at the LHC in 2016. The standard model Z([small nu] [small n̄ū])[small gamma] cross section is measured as a function of photon transverse momentum. No significant deviations from standard model predictions are observed. The results are also interpreted in the context of several new physics models. Limits are placed on new particle masses in simplified models of dark matter, the suppression scale of a dark matter effective field theory model, and the graviton mass scale in a model of extra spatial dimensions.