ELECTROWEAK MEASUREMENTS FROM RUN II AT THE TEVATRON

2004 ◽  
Vol 19 (06) ◽  
pp. 794-807
Author(s):  
T. R. WYATT
Keyword(s):  
Cross Section ◽  
Branching Ratio ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Total Decay Width ◽  
Decay Modes ◽  
Leptonic Decays ◽  
Vector Bosons ◽  
First Time ◽  
Intermediate Vector

The CDF and DØ detectors were fully commissioned for physics running in Run II at the Tevatron [Formula: see text] collider in early 2002. Since then both experiments have collected data samples corresponding to an integrated luminosity of around ∫L=200 pb -1 at a [Formula: see text] centre-of-mass energy of [Formula: see text]. Datasets corresponding ∫L=120 pb-1 have been analyzed for physics so far. Recent electroweak measurements from Run II are reviewed. Cross section times branching ratio measurements (σ· Br ) are presented for the intermediate vector bosons (IVB's) in their leptonic decay modes: W→ℓν and Z→ℓ+ℓ-. For the first time, a combination of the σ· Br results from the CDF and DØ experiments is made; this includes using a consistent choice of the total inelastic [Formula: see text] cross section for the luminosity determinations of the two experiments. Quantities derived from these σ· Br values are also updated. These include: R ℓ the ratio of the σ· Br values for W and Z; Br (W→ℓν), the leptonic branching ratio of the W; and Γw, the total decay width of the W. Other measurements using events containing W and Z leptonic decays are presented, including studies that probe the QCD phenomenology of W/Z production and searches for events containing two intermediate vector bosons.

scholarly journals Study of the process $$e^+e^- \rightarrow \eta \pi ^0\gamma $$ in the energy range $$\sqrt{s} = {1.05-2.00}$$ GeV with the SND detector

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
M. N. Achasov ◽  
A. Yu. Barnyakov ◽  
A. A. Baykov ◽  
K. I. Beloborodov ◽  
A. V. Berdyugin ◽  
...  
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Center Of Mass ◽  
Wide Energy Range ◽  
Mass Energy ◽  
Center Of Mass Energy ◽  
Wide Energy ◽  
Radiation Processes ◽  
Using Data ◽  
First Time

AbstractThe process $$e^+e^-\rightarrow \eta \pi ^0\gamma $$ e + e - → η π 0 γ is studied in the center-of-mass energy range 1.05–2.00 GeV using data with an integrated luminosity of 94.5 $$\hbox {pb}^{-1}$$ pb - 1 collected by the SND detector at the VEPP-2000 $$e^{+}e^{-}$$ e + e - collider. The $$e^+e^-\rightarrow \eta \pi ^0\gamma $$ e + e - → η π 0 γ cross section is measured for the first time. It is shown that the dominant mechanism of this reaction is the transition through the $$\omega \eta $$ ω η intermediate state. The measured cross section of the subprocess $$e^+e^-\rightarrow \omega \eta \rightarrow \eta \pi ^0\gamma $$ e + e - → ω η → η π 0 γ is consistent with previous measurements in the $$e^+e^-\rightarrow \pi ^+\pi ^-\pi ^0\eta $$ e + e - → π + π - π 0 η mode. It is found, with a significance of $$5.6\sigma $$ 5.6 σ , that the process $$e^+e^-\rightarrow \eta \pi ^0\gamma $$ e + e - → η π 0 γ is not completely described by hadronic vector-pseudoscalar intermediate states. The cross section of this missing contribution, which can originate from radiation processes, e. g. $$e^+e^-\rightarrow a_{0}(1450)\gamma $$ e + e - → a 0 ( 1450 ) γ , is measured. It is found to be 15–20 pb in the wide energy range from 1.3 to 1.9 GeV.

scholarly journals Measurement of the inelastic pp cross-section at a centre-of-mass energy of 13 TeV

2018 ◽  
Vol 2018 (6) ◽  
Author(s):  
R. Aaij ◽  
◽  
B. Adeva ◽  
M. Adinolfi ◽  
Z. Ajaltouni ◽  
...  
Keyword(s):  
Cross Section ◽  
Centre Of Mass ◽  
Mass Energy

SEARCH FOR CHARGINOS AND NEUTRALINOS WITH THE DELPHI DETECTOR AT LEP

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 775-777
Author(s):  
◽  
THOMAS ALDERWEIRELD
Keyword(s):  
Cross Section ◽  
Production Cross Section ◽  
Production Cross ◽  
Branching Fraction ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Delphi Detector ◽  
Upper Limit

Search for charginos and neutralinos are presented, based on the data samples recorded in 1999 and 2000 by the DELPHI detector at centre-of-mass energies from 192 to 209 GeV. No evidence for a signal was found. The lower chargino mass limits are 5-6 GeV /c2 higher than those obtained at a centre-of-mass energy of 189 GeV. The (μ, M 2) MSSM domain excluded by combining the chargino searches with neutralino searches at the Z resonance implies a limit on the mass of the lightest neutralino which, for a heavy sneutrino, is constrained to be above 37.6 GeV /c2 for tan β≥1. Upper limit at 95% CL on the neutralino production cross-section times branching fraction are derived.

A measurement of the longitudinal and transverse parts of the π+ electroproduction cross-section at 1175 MeV pion-nucleon centre-of-mass energy

1975 ◽  
Vol 13 (13) ◽  
pp. 485-488 ◽  
Author(s):  
G. Bardin ◽  
J. Duclos ◽  
J. Julien ◽  
A. Magnon ◽  
B. Michel ◽  
...  
Keyword(s):  
Cross Section ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Pion Nucleon

scholarly journals Observation of the decay $$ {\Lambda}_{\mathrm{b}}^0 $$ → χc1pπ−

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
R. Aaij ◽  
◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  
Keyword(s):  
Branching Fractions ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Proton Proton ◽  
Proton Collisions ◽  
Lhcb Detector ◽  
Using Data ◽  
Cabibbo Suppressed ◽  
First Time ◽  
Proton Proton Collisions

Abstract The Cabibbo-suppressed decay $$ {\Lambda}_{\mathrm{b}}^0 $$ Λ b 0 → χc1pπ− is observed for the first time using data from proton-proton collisions corresponding to an integrated luminosity of 6 fb−1, collected with the LHCb detector at a centre-of-mass energy of 13 TeV. Evidence for the $$ {\Lambda}_{\mathrm{b}}^0 $$ Λ b 0 → χc2pπ− decay is also found. Using the $$ {\Lambda}_{\mathrm{b}}^0 $$ Λ b 0 → χc1pK− decay as normalisation channel, the ratios of branching fractions are measured to be$$ {\displaystyle \begin{array}{c}\frac{\mathcal{B}\left({\Lambda}_{\mathrm{b}}^0\to {\upchi}_{\mathrm{c}1}{\mathrm{p}\uppi}^{-}\right)}{\mathcal{B}\left({\Lambda}_{\mathrm{b}}^0\to {\upchi}_{\mathrm{c}1}{\mathrm{p}\mathrm{K}}^{-}\right)}=\left(6.59\pm 1.01\pm 0.22\right)\times {10}^{-2},\\ {}\frac{\mathcal{B}\left({\Lambda}_{\mathrm{b}}^0\to {\upchi}_{\mathrm{c}2}{\mathrm{p}\uppi}^{-}\right)}{\mathcal{B}\left({\Lambda}_{\mathrm{b}}^0\to {\upchi}_{\mathrm{c}1}{\mathrm{p}\uppi}^{-}\right)}=0.95\pm 0.30\pm 0.04\pm 0.04,\\ {}\frac{\mathcal{B}\left({\Lambda}_{\mathrm{b}}^0\to {\upchi}_{\mathrm{c}2}{\mathrm{p}\mathrm{K}}^{-}\right)}{\mathcal{B}\left({\Lambda}_{\mathrm{b}}^0\to {\upchi}_{\mathrm{c}1}{\mathrm{p}\mathrm{K}}^{-}\right)}=1.06\pm 0.05\pm 0.04\pm 0.04,\end{array}} $$ B Λ b 0 → χ c 1 pπ − B Λ b 0 → χ c 1 pK − = 6.59 ± 1.01 ± 0.22 × 10 − 2 , B Λ b 0 → χ c 2 pπ − B Λ b 0 → χ c 1 pπ − = 0.95 ± 0.30 ± 0.04 ± 0.04 , B Λ b 0 → χ c 2 pK − B Λ b 0 → χ c 1 pK − = 1.06 ± 0.05 ± 0.04 ± 0.04 , where the first uncertainty is statistical, the second is systematic and the third is due to the uncertainties in the branching fractions of χc1,2→ J/ψγ decays.

scholarly journals Measurement of the proton-antiproton elastic and total cross section at a centre-of-mass energy of 540 GeV

1982 ◽  
Vol 117 (1-2) ◽  
pp. 126-130 ◽  
Author(s):  
R. Battiston ◽  
M. Bozzo ◽  
P.L. Braccini ◽  
F. Carbonara ◽  
R. Carrara ◽  
...  
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Proton Antiproton
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