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تسجيل مستخدم جديدIndirect measurement of $sin^2 theta_W$ (or $M_W$) using $mu^+mu^-$ pairs from $gamma^*/Z$ bosons produced in $pbar{p}$ collisions at a center-of-momentum energy of 1.96 TeV
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Drell-Yan lepton pairs are produced in the process $pbar{p} rightarrow mu^+mu^- + X$ through an intermediate $gamma^*/Z$ boson. The forward-backward asymmetry in the polar-angle distribution of the $mu^-$ as a function of the invariant mass of the $mu^+mu^-$ pair is used to obtain the effective leptonic determination $sin^2 theta^{lept}_{eff}$ of the electroweak-mixing parameter $sin^2 theta_W$, from which the value of $sin^2 theta_W$ is derived assuming the standard model. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.2 fb-1 of integrated luminosity from $pbar{p}$ collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of $sin^2 theta^{lept}_{eff}$ is found to be 0.2315 +- 0.0010, where statistical and systematic uncertainties are combined in quadrature. When interpreted within the context of the standard model using the on-shell renormalization scheme, where $sin^2 theta_W = 1 - M_W^2/M_Z^2$, the measurement yields $sin^2 theta_W$ = 0.2233 +- 0.0009, or equivalently a W-boson mass of 80.365 +- 0.047 GeV/c^2. The value of the W-boson mass is in agreement with previous determinations in electron-positron collisions and at the Tevatron collider.
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Drell-Yan lepton pairs are produced in the process $pbar{p} rightarrow e^+e^- + X$ through an intermediate $gamma^*/Z$ boson. The lepton angular distributions are used to provide information on the electroweak-mixing parameter $sin^2theta_W$ via its
observable effective-leptonic $sin^2theta_W$, or $sin^2theta^{lept}_{eff}$. A new method to infer $sin^2theta_W$, or equivalently, the W-boson mass M_W in the on-shell scheme, is developed and tested using a previous CDF Run II measurement of angular distributions from electron pairs in a sample corresponding to 2.1 fb-1 of integrated luminosity from $pbar{p}$ collisions at a center-of-momentum energy of 1.96 TeV. The value of $sin^2theta^{lept}_{eff}$ is found to be 0.2328 +- 0.0010. Within a specified context of the standard model, this results in $sin^2theta_W$ = 0.2246 +- 0.0009 which corresponds to a W-boson mass of 80.297 +- 0.048 GeV/c^2, in agreement with previous determinations in electron-position collisions and at the Tevatron collider.
At the Fermilab Tevatron proton-antiproton ($pbar{p}$) collider, Drell-Yan lepton pairs are produced in the process $p bar{p} rightarrow e^+e^- + X$ through an intermediate $gamma^*/Z$ boson. The forward-backward asymmetry in the polar-angle distribu
tion of the $e^-$ as a function of the $e^+e^-$-pair mass is used to obtain $sin^2theta^{rm lept}_{rm eff}$, the effective leptonic determination of the electroweak-mixing parameter $sin^2theta_W$. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.4~fb$^{-1}$ of integrated luminosity from $pbar{p}$ collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of $sin^2theta^{rm lept}_{rm eff}$ is found to be $0.23248 pm 0.00053$. The combination with the previous CDF measurement based on $mu^+mu^-$ pairs yields $sin^2theta^{rm lept}_{rm eff} = 0.23221 pm 0.00046$. This result, when interpreted within the specified context of the standard model assuming $sin^2 theta_W = 1 - M_W^2/M_Z^2$ and that the $W$- and $Z$-boson masses are on-shell, yields $sin^2theta_W = 0.22400 pm 0.00045$, or equivalently a $W$-boson mass of $80.328 pm 0.024 ;{rm GeV}/c^2$.
At the Fermilab Tevatron proton-antiproton ($pbar{p}$) collider, high-mass electron-neutrino ($e u$) pairs are produced predominantly in the process $p bar{p} rightarrow W(rightarrow e u) + X$. The asymmetry of the electron and positron yield as a fu
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Differential cross sections for the production of $Z$ bosons or off-shell photons $gamma^*$ in association with jets are measured in proton-antiproton collisions at center-of-mass energy $sqrt{s}=1.96$ TeV using the full data set collected with the C
ollider Detector at Fermilab in Tevatron Run II, and corresponding to 9.6 fb$^{-1}$ of integrated luminosity. Results include first measurements at CDF of differential cross sections in events with a $Z/gamma^*$ boson and three or more jets, the inclusive cross section for production of $Z/gamma^*$ and four or more jets, and cross sections as functions of various angular observables in lower jet-multiplicity final states. Measured cross sections are compared to several theoretical predictions.
The transverse momentum cross section of $e^+e^-$ pairs in the $Z$-boson mass region of 66-116 GeV/$c^2$ is precisely measured using Run II data corresponding to 2.1 fb$^{-1}$ of integrated luminosity recorded by the Collider Detector at Fermilab. Th
e cross section is compared with quantum chromodynamic calculations. One is a fixed-order perturbative calculation at ${cal O}(alpha_s^2)$, and the other combines perturbative predictions at high transverse momentum with the gluon resummation formalism at low transverse momentum. Comparisons of the measurement with calculations show reasonable agreement. The measurement is of sufficient precision to allow refinements in the understanding of the transverse momentum distribution.
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