Measurement of the Top Quark Mass in the Lepton+Jets Channel Using the Lepton Transverse Momentum

Measurement of the Top Quark Mass in the Lepton+Jets Channel Using the Lepton Transverse Momentum
Author:
Publisher:
Total Pages:
Release: 2011
Genre:
ISBN:

This letter reports a measurement of the top quark mass, M{sub top}, in data from p{bar p} collisions at (square root)s = 1.96 TeV corresponding to 2.7 fb−1 of integrated luminosity at the Fermilab Tevatron using the CDF II detector. Events with the lepton+jets topology are selected. An unbinned likelihood is constructed based on the dependence of the lepton transverse momentum, P{sub T}, on M{sub top}. A maximum likelihood fit to the data yields a measured mass M{sub top} = 176.9 ± 8.0{sub stat} ± 2.7{sub syst} GeV/c2. In this measurement, the contribution by the jet energy scale uncertainty to the systematic error is negligible. The result provides an important consistency test for other M{sub top} measurements where explicit use of the jet energy is made for deriving the top quark mass.

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.

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 Top-quark Mass Using Charged Particle Tracking

Measurements of the Top-quark Mass Using Charged Particle Tracking
Author:
Publisher:
Total Pages:
Release: 2009
Genre:
ISBN:

We present three measurements of the top-quark mass in the lepton plus jets channel with approximately 1.9 fb−1 of integrated luminosity collected with the CDF II detector using quantities with minimal dependence on the jet energy scale. One measurement exploits the transverse decay length of b-tagged jets to determine a top-quark mass of 166.9{sub -8.5}{sup +9.5} (stat) ± 2.9 (syst) GeV/c2, and another the transverse momentum of electrons and muons from W-boson decays to determine a top-quark mass of 173.5{sub -8.9}{sup +8.8} (stat) ± 3.8 (syst) GeV/c2. These quantities are combined in a third, simultaneous mass measurement to determine a top-quark mass of 170.7 ± 6.3 (stat) ± 2.6 (syst) GeV/c2.

The Top Quark Mass, Systematic Limitations, and My Tracker-driven Measurements

The Top Quark Mass, Systematic Limitations, and My Tracker-driven Measurements
Author: Ford Garberson
Publisher:
Total Pages: 376
Release: 2009
Genre:
ISBN: 9781109483871

I perform my measurements of the top quark mass in the lepton plus jets channel with approximately 1.9 fb-1 of integrated luminosity collected with the CDF II detector using quantities with minimal dependence on the jet energies. One measurement exploits the transverse decay length of b-tagged jets to determine a top quark mass of 166.9+9.5-8.5 (stat) +/- 2.9 (syst) GeV/c2, and another the transverse momentum of electrons and muons from Wdecays to determine a top quark mass of 173.5+8.8-8.9 (stat) +/- 3.8 (syst) GeV/c2. I combine these quantities in a third, simultaneous mass measurement to determine a top quark mass of 170.7 +/- 6.3 (stat) +/- 2.6 (syst) GeV/ c2.

The Top Quark Mass, Systematic Limitations, and My Tracker-Driven Measurements

The Top Quark Mass, Systematic Limitations, and My Tracker-Driven Measurements
Author:
Publisher:
Total Pages: 199
Release: 2008
Genre:
ISBN:

Top quark mass measurements have achieved an unexpected level of accu- racy in the last several years. This accuracy is only possible because of a new procedure that calibrates away the dominant jet energy uncertainty of past mea- surements. In this thesis I present some studies illustrating my suspicions that this procedure is leading them to claim overly optimistic results. Additionally, I present three measurements of the top quark mass that will be almost entirely independent of jet energies, and will thus serve as important cross checks of the standard measurements once enough statistics have been collected. I perform my measurements of the top quark mass in the lepton plus jets channel with approximately 1.9 fb-1 of integrated luminosity collected with the CDF detector using quantities with minimal dependence on the jet energies. One measurement exploits the transverse decay length of b-tagged jets to determine a top quark mass of 166.9+9.5 (stat)±2.9 (syst) GeV/c2, and another the transverse momentum of electrons and muons from W decays to determine a top quark mass of 173.5+8.8 - (stat) ± 3.8 (syst) GeV/c2. I combine these quantities in a vi third, simultaneous mass measurement to determine a top quark mass of 170.7 ± 6.3 (stat) ± 2.6 (syst) GeV/c2.

Measurement of the Top-quark Mass in the Lepton+jets Channel Using a Matrix Element Technique with the CDF II Detector

Measurement of the Top-quark Mass in the Lepton+jets Channel Using a Matrix Element Technique with the CDF II Detector
Author:
Publisher:
Total Pages: 9
Release: 2011
Genre:
ISBN:

A measurement of the top-quark mass is presented using Tevatron data from proton-antiproton collisions at center-of-mass energy √ = 1.96 TeV collected with the CDF II detector. Events are selected from a sample of candidates for production of t{bar t} pairs that decay into the lepton+jets channel. The top-quark mass is measured with an unbinned maximum likelihood method where the event probability density functions are calculated using signal and background matrix elements, as well as a set of parameterized jet-to-parton transfer functions. The likelihood function is maximized with respect to the top-quark mass, the signal fraction in the sample, and a correction to the jet energy scale (JES) calibration of the calorimeter jets. The simultaneous measurement of the JES correction ([Delta]{sub JES}) amounts to an additional in situ jet energy calibration based on the known mass of the hadronically decaying W boson. Using the data sample of 578 lepton+jets candidate events, corresponding to 3.2 fb−1 of integrated luminosity, the top-quark mass is measured to be m{sub t} = 172.4 ± 1.4 (stat + [Delta]{sub JES}) ± 1.3 (syst) GeV/c2.

Top Quark Mass Measurement in the Lepton + Jets Channel Using a Matrix Element Method and \textit{in Situ} Jet Energy Calibration

Top Quark Mass Measurement in the Lepton + Jets Channel Using a Matrix Element Method and \textit{in Situ} Jet Energy Calibration
Author:
Publisher:
Total Pages: 7
Release: 2010
Genre:
ISBN:

A precision measurement of the top quark mass m{sub t} is obtained using a sample of t{bar t} events from p{bar p} collisions at the Fermilab Tevatron with the CDF II detector. Selected events require an electron or muon, large missing transverse energy, and exactly four high-energy jets, at least one of which is tagged as coming from a b quark. A likelihood is calculated using a matrix element method with quasi-Monte Carlo integration taking into account finite detector resolution and jet mass effects. The event likelihood is a function of m{sub t} and a parameter [Delta]{sub JES} used to calibrate the jet energy scale in situ. Using a total of 1087 events, a value of m{sub t} = 173.0 ± 1.2 GeV/c2 is measured.