Radiative Correction to e+ e- -&gt;   in Electroweak Theory

Fujimoto, J.; Igarashi, M.; Shimizu, Y.

doi:10.1143/ptp.77.118

Cited by 25 publications

(8 citation statements)

References 1 publication

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“…The parameter ε is defined as: 11) where the coefficient λ is of order 1 and cannot be calculated explicitly without knowledge of the full quantum gravity theory. In the following analysis we will assume that λ = ±1 in order to study both the cases of positive and negative interference.…”

Section: Large Extra Dimensionsmentioning

confidence: 99%

Electroweak measurements in electron–positron collisions at W-boson-pair energies at LEP

2013

Physics Reports

593

446

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Electroweak measurements performed with data taken at the electron-positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3 fb −1 collected by the four LEP experiments ALEPH, DELPHI, L3 and OPAL, at centre-of-mass energies ranging from 130 GeV to 209 GeV.Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron-positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose-Einstein correlations between the two W decay systems arising in WW production, are searched for and upper limits on the strength of possible effects are obtained. The data are used to determine fundamental properties of the W boson and the electroweak theory. Among others, the mass and width of the W boson, m W and Γ W , the branching fraction of W decays to hadrons, B(W → had), and the trilinear gauge-boson selfcouplings g

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Section: Large Extra Dimensionsmentioning

confidence: 99%

Electroweak measurements in electron–positron collisions at W-boson-pair energies at LEP

2013

Physics Reports

593

446

View full text Add to dashboard Cite

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“…At the W-pair threshold weak corrections of up to 1.2% are expected for cos θ = 0 [34,35]. At the energies considered in this analysis the corrections are smaller, e.g.…”

Section: Qed Born Cross-sectionmentioning

confidence: 73%

Multi-photon production in ee collisions at $\sqrt{s} = $ 181-209 GeV

Abbiendi¹,

Ainsley²,

Åkesson³

et al. 2003

Eur. Phys. J. C

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The process e + e − → γγ(γ) is studied using data collected by the OPAL detector at LEP between the years 1997 and 2000. The data set corresponds to an integrated luminosity of 672.3 pb −1 at centre-of-mass energies lying between 181 GeV and 209 GeV. Total and differential cross-sections are determined and found to be in good agreement with the predictions of QED. Fits to the observed angular distributions are used to set limits on parameters from several models of physics beyond the Standard Model such as cut-off parameters, contact interactions of the type e + e − γγ, gravity in extra spatial dimensions and excited electrons. In events with three photons in the final state the mass spectrum of photon pairs is investigated. No narrow resonance X → γγ is found and limits are placed on the product of the Xγ production crosssection and branching ratio.

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“…The data analysed were collected with the DELPHI detector [1] at LEP 2, at collision energies, √ s, ranging from 161 GeV up to 208 GeV, corresponding to a total integrated luminosity of 656.4 pb −1 . The studied reaction is an almost pure QED (Quantum ElectroDynamics) process which, at orders above α 2 , is mainly affected by QED corrections, such as soft and hard bremsstrahlung and virtual corrections, compared to which the weak corrections due to the exchange of virtual massive gauge bosons are very small [2][3][4]. Therefore, any significant deviation between the measured and the predicted QED cross-sections could unambiguously be interpreted as a manifestation of non-standard physics.…”

Section: Introductionmentioning

confidence: 94%

Determination of the $e^ + e^- \to \gamma \gamma (\gamma)$ cross-section at LEP 2

et al. 2004

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Determination of the e + e − → γγ (γ) cross-section at LEP 2 DELPHI CollaborationAbstract A test of the benchmark QED process e + e − → γγ(γ) is reported, using the data collected with the DELPHI detector at LEP 2. The data analysed were recorded at centre-of-mass energies ranging from 161 GeV to 208 GeV and correspond to a total integrated luminosity of 656.4 pb −1 . The Born cross-section for the process e + e − → γγ(γ) was determined, confirming the validity of QED at the highest energies ever attained in electron-positron collisions. Lower limits on the parameters of a number of possible deviations from QED, predicted within theoretical frameworks expressing physics beyond the Standard Model, were derived.(Accepted by Eur. Phys. J. C) IntroductionAn analysis of the process e + e − → γγ(γ) is reported. The data analysed were collected with the DELPHI detector [1] at LEP 2, at collision energies, √ s, ranging from 161 GeV up to 208 GeV, corresponding to a total integrated luminosity of 656.4 pb −1 . The studied reaction is an almost pure QED (Quantum ElectroDynamics) process which, at orders above α 2 , is mainly affected by QED corrections, such as soft and hard bremsstrahlung and virtual corrections, compared to which the weak corrections due to the exchange of virtual massive gauge bosons are very small [2][3][4]. Therefore, any significant deviation between the measured and the predicted QED cross-sections could unambiguously be interpreted as a manifestation of non-standard physics. Moreover, the differential crosssection terms expressing interferences between QED and various non-standard physics processes, behave very differently from the QED term in their dependence on the scattering angle of the photons with respect to the incident electron/positron. Depending on the possible new physics scenario, a departure of the measured differential cross-section of e + e − → γγ from the Standard Model expectations, could then be interpreted as a measure of the energy scale of the QED breakdown [5,6], of the characteristic energy scales of e + e − γγ contact interactions [7], of the mass of excited electrons within composite models [8] or of the string mass scale [9,10] (which could be of the order of the electroweak scale in the framework of models with gravity propagating in large extra-dimensions).The data recorded by DELPHI at LEP 2 were treated according to common reconstruction procedures, selection criteria and treatment of systematic uncertainties. Previous results concerning the process e + e − → γγ(γ), using DELPHI LEP 1 data are reported in reference [11]. An analysis of the LEP 2 data collected in 1996 and 1997 can be found in reference [12], while the analysis of the 1998 and 1999 DELPHI data, from which the present analysis framework evolved is reported in [13]. The results reported in the previous publications concerning the analyses of LEP 2 data are superseded by the results hereby reported. The most recently published results from the other LEP collaborations can be found in references [14][15...

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Radiative Correction to e+ e- -> in Electroweak Theory

Cited by 25 publications

References 1 publication

Electroweak measurements in electron–positron collisions at W-boson-pair energies at LEP

Electroweak measurements in electron–positron collisions at W-boson-pair energies at LEP

Multi-photon production in ee collisions at $\sqrt{s} = $ 181-209 GeV

Determination of the $e^ + e^- \to \gamma \gamma (\gamma)$ cross-section at LEP 2

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