Total Cross-Section Measurements

Total Cross-Section Measurements
Author: G. Giacomelli
Publisher: Elsevier
Total Pages: 152
Release: 2013-10-22
Genre: Science
ISBN: 1483181529

Total Cross-Section Measurements discusses the cross-sectional dimensions of elementary hadron collisions. The main coverage of the book is the resonance and high energy area of the given collision. A section of the book explains in detail the characteristic of a resonance region. Another section is focused on the location of the high energy region of collision. Parts of the book define the meaning of resonance in nuclear physics. Also explained are the measurement of resonance and the identification of the area where the resonance originates. Different experimental methods to measure the total cross section of a charged particle are given. One such method is the transmission method. Bubble chamber measurement is another method that is covered in the book. Systems of analysis such as the pion-nucleon system, the K–-nucleon system, and K+- nucleon system are discussed. The book is an excellent guide for nuclear physicists and students of physics.

Top Quark Pair Production

Top Quark Pair Production
Author: Anna Christine Henrichs
Publisher: Springer Science & Business Media
Total Pages: 231
Release: 2013-10-04
Genre: Science
ISBN: 3319014870

Before any kind of new physics discovery could be made at the LHC, a precise understanding and measurement of the Standard Model of particle physics' processes was necessary. The book provides an introduction to top quark production in the context of the Standard Model and presents two such precise measurements of the production of top quark pairs in proton-proton collisions at a center-of-mass energy of 7 TeV that were observed with the ATLAS Experiment at the LHC. The presented measurements focus on events with one charged lepton, missing transverse energy and jets. Using novel and advanced analysis techniques as well as a good understanding of the detector, they constitute the most precise measurements of the quantity at that time.

Top-Quark Pair Production Cross Sections and Calibration of the Top-Quark Monte-Carlo Mass

Top-Quark Pair Production Cross Sections and Calibration of the Top-Quark Monte-Carlo Mass
Author: Jan Kieseler
Publisher: Springer
Total Pages: 172
Release: 2016-06-15
Genre: Science
ISBN: 3319400053

This thesis presents the first experimental calibration of the top-quark Monte-Carlo mass. It also provides the top-quark mass-independent and most precise top-quark pair production cross-section measurement to date. The most precise measurements of the top-quark mass obtain the top-quark mass parameter (Monte-Carlo mass) used in simulations, which are partially based on heuristic models. Its interpretation in terms of mass parameters used in theoretical calculations, e.g. a running or a pole mass, has been a long-standing open problem with far-reaching implications beyond particle physics, even affecting conclusions on the stability of the vacuum state of our universe. In this thesis, this problem is solved experimentally in three steps using data obtained with the compact muon solenoid (CMS) detector. The most precise top-quark pair production cross-section measurements to date are performed. The Monte-Carlo mass is determined and a new method for extracting the top-quark mass from theoretical calculations is presented. Lastly, the top-quark production cross-sections are obtained – for the first time – without residual dependence on the top-quark mass, are interpreted using theoretical calculations to determine the top-quark running- and pole mass with unprecedented precision, and are fully consistently compared with the simultaneously obtained top-quark Monte-Carlo mass.

Measurement of the Top Quark Mass in the Dilepton Final State Using the Matrix Element Method

Measurement of the Top Quark Mass in the Dilepton Final State Using the Matrix Element Method
Author: Alexander Grohsjean
Publisher: Springer Science & Business Media
Total Pages: 155
Release: 2010-10-01
Genre: Science
ISBN: 364214070X

The main pacemakers of scienti?c research are curiosity, ingenuity, and a pinch of persistence. Equipped with these characteristics a young researcher will be s- cessful in pushing scienti?c discoveries. And there is still a lot to discover and to understand. In the course of understanding the origin and structure of matter it is now known that all matter is made up of six types of quarks. Each of these carry a different mass. But neither are the particular mass values understood nor is it known why elementary particles carry mass at all. One could perhaps accept some small generic mass value for every quark, but nature has decided differently. Two quarks are extremely light, three more have a somewhat typical mass value, but one quark is extremely massive. It is the top quark, the heaviest quark and even the heaviest elementary particle that we know, carrying a mass as large as the mass of three iron nuclei. Even though there exists no explanation of why different particle types carry certain masses, the internal consistency of the currently best theory—the standard model of particle physics—yields a relation between the masses of the top quark, the so-called W boson, and the yet unobserved Higgs particle. Therefore, when one assumes validity of the model, it is even possible to take precise measurements of the top quark mass to predict the mass of the Higgs (and potentially other yet unobserved) particles.

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

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.

Total Photon Absorption Cross Section Measurements, Theroretical Analysis and Evaluations for Energies Above 10 MeV

Total Photon Absorption Cross Section Measurements, Theroretical Analysis and Evaluations for Energies Above 10 MeV
Author: H. A. Gimm
Publisher:
Total Pages: 84
Release: 1978
Genre: Absorption
ISBN:

Atomic photoabsorption cross sections have been calculated in the energy range from 10 MeV to 350 MeV. For Pb, Ta, Sn and Cu total y-ray absorption cross sections were measured between 10 MeV and 160 MeV and compared with the theoretical results. An estimate of the uncertainties in the calculated atomic cross sections is given.