Measurement of the W Boson Mass with the D/O Detector Using the Electron ET Spectrum PDF Download

Author: Ian Malcolm Adam
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Category :
Languages : en
Pages : 656

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Author:
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Category :
Languages : en
Pages : 179

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This thesis is a description of the measurement of the W boson mass using the D0 Run II detector with 770 pb−1 of p{bar p} collision data. These collisions were produced by the Tevatron at √s = 1.96 TeV between 2002 and 2006. We use a sample of W → e[nu] and Z → ee decays to determine the W boson mass with the transverse momentum distribution of the electron and the transverse mass distribution of the boson. We measure M{sub W} = XXXXX ± 37 (stat.) ± 26 (sys. theo.) ± 51 (sys. exp.) MeV = XXXXX ± 68 MeV with the transverse momentum distribution of the electron and M{sub W} = XXXXX ± 28 (stat.) ± 17 (sys. theo.) ± 51 (sys. exp.) MeV = XXXXX ± 61 MeV with the transverse mass distribution.

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Languages : en
Pages : 9

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I present the first measurement of the W boson mass in the electron decay channel using the Run II D0 detector at the Fermilab Tevatron Collider. The data used was collected from 2002 to 2006 and the integrated luminosity is 1 fb−1. The W boson mass was determined from the likelihood fit to the measured data distribution. The mass value is found to be 80.401 ± 0.023(stat) ± 0.037(syst) GeV = 80.401 ± 0.044 GeV using the transverse mass spectrum, which is the most precise measurement from one single experiment to date. This result puts tighter constraints on the mass of the standard model Higgs boson. I also present three other measurements that can help to reduce the theoretical uncertainties for the future W mass measurements.

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Languages : en
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We present a preliminary measurement of the[ital W] boson mass using data collected by the D[null] experiment at the Fermilab Tevatron during the 1994-1995 collider run 1b. We use[ital W][r-arrow][ital e][nu] decays to extract the[ital W] mass from the observed spectrum of transverse mass of the electron ([vert-bar][eta][vert-bar][lt] 1. 2) and the inferred neutrino We use[ital Z][sup 0][r-arrow][ital ee] decays to constrain our model of the detector response. We measure[ital m][sub W]/[ital m][sub Z]= 0.8815[+-] 0.0011([ital stat])[+-] 0.0014([ital syst]) and[ital m][sub W]= 80.38[+-] 0.07 ([ital W stat])[+-] 0.13([ital syst]) GeV. Combining this result with our previous measurement from the 1992-1993 data, we obtain[ital m][sub W]= 80.37[+-] 0.15 GeV (errors combined in quadrature).

Author:
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Category :
Languages : en
Pages : 120

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This thesis describes a measurement of the W boson mass from a fit to the transverse momentum spectrum of the muon in W decay. In past measurements this technique was used as a cross-check, however, now presents the best method in terms of systematic uncertainty. We discuss all sources of systematic uncertainty with emphasis on those to which the muon p{sub T} measurement is particularly sensitive, specifically, those associated with modeling the production and decay of W bosons. The data were collected with the CDF II detector between March 2002 and September 2003 and correspond to an integrated luminosity of (191 ± 11) pb−1. We measure the W mass to be (80.316 ± 0.066{sub stat.} ± 0.051{sub syst.}) GeV/c2 = (80.316 ± 0.083) GeV/c2.

Author: Ian E. Vollrath
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ISBN: 9780494280812
Category :
Languages : en
Pages : 216

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This thesis describes a measurement of the W boson mass from a fit to the transverse momentum spectrum of the muon in W decay. In past measurements this technique was used as a cross-check, however, now presents the best method in terms of systematic uncertainty. We discuss all sources of systematic uncertainty with emphasis on those to which the Muon pT measurement is particularly sensitive, specifically, those associated with modelling the production and decay of W bosons. The data were collected with the CDF II detector between March 2002 and September 2003 and correspond to an integrated luminosity of (191 +/- 11) pb-1. We measure the W mass to be (80.316 +/- 0.066stat. +/- 0.051syst.) GeV/c2 = (80.316 +/- 0.083) GeV/ c2.

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Category :
Languages : en
Pages : 254

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In the first part, we describe what is the W boson mass in the context of the Standard Model. We discuss the prominent role this physical observable plays in the determination of the internal self consistency of the Electroweak Sector. We review measurements and calculation of the W boson mass done in past and argue about the importance and feasibility of improving the experimental determination. We give a description of the Fermilab Tevatron Collider and the D0 detector, highlighting the relevant parts for the measurement described in this Dissertation. In the second part, we give a detailed description of a measurement of the W boson mass using the D0 Central Calorimeter. The measurement uses 1.68 x 106 candidates from W → en decays, corresponding to 4.3 fb-1 of integrated luminosity collected from 2006 to 2009. We measure the mass using the transverse mass, electron transverse momentum, and missing transverse energy distributions. The transverse mass and electron transverse momentum measurements are the most precise and are combined to give MW = 80.367 ± 0.013(stat) ± 0.023 (syst) GeV = 80.367 ± 0.026 GeV. This is combined with an earlier D0 result determined using an independent 1 fb-1 data sample, also with central electrons only, to give MW = 80.375± 0.023 GeV. The uncertainty in the measurement is dominated by the determination of the calorimeter electron energy scale, the W sample size, the knowledge of the parton distribution function. In the third part, we discuss methods of reducing the dominant uncertainties in the W boson mass measurements. We show that introducing electrons detected in the End Calorimeters greatly reduce the measurement systematic uncertainty, especially the on related to the parton distribution functions. We describe a precise calibration of the End Calorimeter using Z → ee events corresponding to 4.3 fb-1 of integrated luminosity. The calibration is an important milestone in a measurement that explores a larger part of the D0 Calorimeter. We present parametrized models that describe the response of the End Calorimeters to electron showers and soft hadronic particles, giving special attention to the specific challenges of a measurement in the forward region: the inhomogeneity of the uninstrumented materials, the large hadronic energy flow in the calorimeter and the jet misidentification probability.

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Category :
Languages : en
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We give a detailed description of the measurement of the $W$ boson mass, $M_W$, performed on an integrated luminosity of 4.3 fb$^{-1}$, which is based on similar techniques as used for our previous measurement done on an independent data set of 1 fb$^{-1}$ of data. The data were collected using the D0 detector at the Fermilab Tevatron Collider. This data set yields $1.68\times 10^6$ $W\rightarrow e\nu$ candidate events. We measure the mass using the transverse mass, electron transverse momentum, and missing transverse energy distributions. The $M_W$ measurements using the transverse mass and the electron transverse momentum distributions are the most precise of these three and are combined to give $M_W$ = 80.367 $\pm$ 0.013 (stat) $\pm$ 0.022 (syst) GeV = 80.367 $\pm$ 0.026 GeV. When combined with our earlier measurement on 1 fb$^{-1}$ of data, we obtain $M_W$ = 80.375 $\pm$ 0.023 GeV.

Author: Oleh Kivernyk
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ISBN:
Category :
Languages : en
Pages : 0

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This thesis describes a measurement of the W boson mass with the ATLAS detector based on the data-set recorded by ATLAS in 2011 at a centre-of-mass energy of 7 TeV, and corresponding to 4.6 inverse femtobarn of integrated luminosity. Measurements are performed through template fits to the transverse momentum distributions of charged leptons and to transverse mass distributions of the W boson, in electron and muon decay modes in various kinematic categories. The individual measurements are found to be consistent and their combination leads to a value of m_W = 80371.1 ± 18.6 MeV. The measured value of the W boson mass is compatible with the current world average of m_W = 80385 ± 15 MeV. The uncertainty is competitive with the current most precise measurements performed by the CDF and D0 collaborations.

Author:
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Category :
Languages : en
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The W boson mass has been extracted using W-pairs decaying into evqq and mvqq final states. The events were selected from the data collected with the ALEPH detector during the years 1998, 1999 and 2000, corresponding to a total integrated luminosity of about 650 pb-1. A kinematic fit imposing four-momentum conservation is then applied to improve the invariant mass resolution. The W boson mass is obtained from the invariant mass spectrum by a Monte Carlo reweighting method. Since the statistical and systematical uncertainties are at the same level, the latter are investigated in great detail. The presented W boson mass is then included in a preliminary world average which is used to extract a upper limit on the Higgs boson mass.