FIRST MEASUREMENT OF THE LEFT-RIGHT ASYMMETRY IN Z-BOSON PRODUCTION

1993 ◽  
Vol 08 (24) ◽  
pp. 2237-2248 ◽  
Author(s):  
◽  
K. ABE ◽  
I. ABT ◽  
P. D. ACTON ◽  
C. E. ADOLPHSEN ◽  
...  
Keyword(s):  
Z Boson ◽  
Linear Collider ◽  
Center Of Mass ◽  
Positron Beam ◽  
Beam Polarization ◽  
Boson Production ◽  
Weak Mixing Angle ◽  
Center Of Mass Energy ◽  
Average Electron ◽  
Left Right Asymmetry

We present the first measurement of the left-right cross-section asymmetry (A LR ) in Z-boson production observed at the SLAC Linear Collider. In 1992 the SLD detector recorded 10 224 Z events produced by the collision of longitudinally polarized electrons with an unpolarized positron beam at a center-of-mass energy of 91.55 GeV. The average electron beam polarization during the run was (22.4 ± 0.6)%. We measure A LR to be 0.100 ± 0.0440 (stat.) ±0.004 (syst.) , which determines the effective weak mixing angle to be [Formula: see text].

scholarly journals Probe of the Anomalous Quartic Couplings with Beam Polarization at the CLIC

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
A. Senol ◽  
M. Köksal ◽  
S. C. İnan
Keyword(s):  
Confidence Level ◽  
Semileptonic Decay ◽  
Linear Collider ◽  
Decay Channel ◽  
Center Of Mass ◽  
Positron Beam ◽  
Beam Polarization ◽  
Electron Positron ◽  
Integrated Luminosity

We have investigated the anomalous quartic couplings defined by the dimension-8 operators in semileptonic decay channel of thee+e-→νeW-W+ν-eprocess for unpolarized and polarized electron (positron) beam at the Compact Linear Collider. We give the 95% confidence level bounds on the anomalousfS0/Λ4,fS1/Λ4, andfT0/Λ4couplings for various values of the integrated luminosities and center-of-mass energies. The best sensitivities obtained on anomalousfS0/Λ4,fS1/Λ4, andfT0/Λ4couplings through the processe+e-→νeW-W+ν-ewith beam polarization ats=3 TeV and an integrated luminosity ofLint=2000 fb-1are[-4.05;3.67]×10-12 GeV-4,[-3.08;2.12]×10-12 GeV-4, and[-1.98;0.64]×10-13 GeV-4, which show improvement over the current bounds.

scholarly journals Measurements of the differential cross sections of the production of Z + jets and γ + jets and of Z boson emission collinear with a jet in pp collisions at $$ \sqrt{s} $$ = 13 TeV

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
◽  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Z Boson ◽  
Center Of Mass ◽  
Z Bosons ◽  
Differential Cross Sections ◽  
Pp Collisions ◽  
Center Of Mass Energy ◽  
Cms Experiment ◽  
Theoretical Predictions

Abstract Measurements of the differential cross sections of Z + jets and γ + jets production, and their ratio, are presented as a function of the boson transverse momentum. Measurements are also presented of the angular distribution between the Z boson and the closest jet. The analysis is based on pp collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 35.9 fb−1 recorded by the CMS experiment at the LHC. The results, corrected for detector effects, are compared with various theoretical predictions. In general, the predictions at higher orders in perturbation theory show better agreement with the measurements. This work provides the first measurement of the ratio of the differential cross sections of Z + jets and γ + jets production at 13 TeV, as well as the first direct measurement of Z bosons emitted collinearly with a jet.

scholarly journals Z-boson production in p-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ = 8.16 TeV and Pb-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ = 5.02 TeV

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
S. Acharya ◽  
◽  
D. Adamová ◽  
A. Adler ◽  
J. Adolfsson ◽  
...  
Keyword(s):  
Z Boson ◽  
Decay Channel ◽  
Theoretical Calculations ◽  
Center Of Mass ◽  
Laboratory Frame ◽  
Distribution Functions ◽  
Boson Production ◽  
Free Nucleon ◽  
Parton Distribution Functions ◽  
Nuclear Modifications

Abstract Measurement of Z-boson production in p-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ s NN = 8.16 TeV and Pb-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ s NN = 5.02 TeV is reported. It is performed in the dimuon decay channel, through the detection of muons with pseudorapidity −4 < ημ< −2.5 and transverse momentum $$ {p}_{\mathrm{T}}^{\mu } $$ p T μ > 20 GeV/c in the laboratory frame. The invariant yield and nuclear modification factor are measured for opposite-sign dimuons with invariant mass 60 < mμμ< 120 GeV/c2 and rapidity 2.5 <$$ {y}_{\mathrm{cms}}^{\mu \mu} $$ y cms μμ < 4. They are presented as a function of rapidity and, for the Pb-Pb collisions, of centrality as well. The results are compared with theoretical calculations, both with and without nuclear modifications to the Parton Distribution Functions (PDFs). In p-Pb collisions the center-of-mass frame is boosted with respect to the laboratory frame, and the measurements cover the backward (−4.46 <$$ {y}_{\mathrm{cms}}^{\mu \mu} $$ y cms μμ < −2.96) and forward (2.03 <$$ {y}_{\mathrm{cms}}^{\mu \mu} $$ y cms μμ < 3.53) rapidity regions. For the p-Pb collisions, the results are consistent within experimental and theoretical uncertainties with calculations that include both free-nucleon and nuclear-modified PDFs. For the Pb-Pb collisions, a 3.4σ deviation is seen in the integrated yield between the data and calculations based on the free-nucleon PDFs, while good agreement is found once nuclear modifications are considered.

scholarly journals The measurement of the $$H\rightarrow \tau \tau $$ signal strength in the future $$e^{+}e^{-}$$ Higgs factories

2020 ◽  
Vol 80 (1) ◽  
Author(s):  
Dan Yu ◽  
Manqi Ruan ◽  
Vincent Boudry ◽  
Henri Videau ◽  
Jean-Claude Brient ◽  
...  
Keyword(s):  
Linear Collider ◽  
Simulation Analysis ◽  
Center Of Mass ◽  
International Linear Collider ◽  
Signal Strength ◽  
Relative Accuracy ◽  
Hadronic Decay ◽  
Beam Polarization ◽  
Baseline Design ◽  
Electron Positron

AbstractThe Circular Electron Positron Collider and the International Linear Collider are two electron-positron Higgs factories. They are designed to operate at a center-of-mass energy of 240 and 250 GeV and accumulate 5.6 and 2 $$ab^{-1}$$ab-1 of integrated luminosity. This paper estimates their performance on the $$H \rightarrow \tau ^{+}\tau ^{-}$$H→τ+τ- benchmark measurement. Using the full simulation analysis, the CEPC is expected to measure the signal strength to a relative accuracy of 0.8%. Extrapolating to the ILC setup, we conclude the ILC can reach a relative accuracy of 1.1% or 1.2%, corresponding to two benchmark beam polarization setups. The physics requirement on the mass resolution of the Higgs boson with hadronic decay final states is also discussed, showing that the CEPC baseline design and reconstruction fulfill the accuracy requirement of the $$H\rightarrow \tau ^{+}\tau ^{-}$$H→τ+τ- signal strength.

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