e+e−→W+W−→4f(+γ) at LEP2

The complete electroweak O(α) corrections have been calculated for the chargedcurrent four-fermion production processes e + e − → ν τ τ + µ −ν µ , udµ −ν µ , and udsc. Here, technical details of this calculation are presented. These include the algebraic reduction of spinor chains to a few standard structures and the consistent implementation of the finite width of the W boson. To this end, a generalization of the complex-mass scheme to the one-loop level is proposed, and the practical application of this method is described. Finally, the effects of the complete O(α) corrections to various differential cross sections of physical interest are discussed and compared to predictions based on the double-pole approximation, revealing that the latter approximation is not sufficient to fully exploit the potential of a future linear collider in an analysis of W-boson pairs at high energies.August 2011 1 Some of the problems appearing in a first attempt of such a calculation were already described in Ref. [ 25]. 2 The recently proposed approach [ 35] to describe unstable particles within an effective field theory is equivalent to a pole expansion.

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“…we can approximate the mass and wave-function renormalization counterterms as 22) and the resulting approximation…”

Section: (Ii) a Simplified Version Of The Complex Renormalizationmentioning

confidence: 99%

Electroweak corrections to charged-current e+e−→4 fermion processes: Technical details and further results

et al. 2005

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“…if the photon energy k 0 ∼ Γ W ). A detailed comparison [46] between the various results in DPA [195,610,[619][620][621][622][623] as well as several uncertainty estimates within the different approaches confirmed the validity of the DPA within a precision margin of 0.5% for W-pair production in the energy range 170 GeV √ s 300 GeV, which in particular covers the energy range of LEP2 where W-pair production was accessible within good precision. Note that the DPA necessarily breaks down near the threshold energy √ s = 2M W , because at least one of the two W bosons is shifted out of resonance below threshold.…”

Section: Multiple Resonances In Pole Approximation and Gauge-boson Pa...mentioning

confidence: 79%

“…These results were obtained by generalizing the corresponding corrections to EW gauge-boson pair production processes first derived for W-pair production [606][607][608]613]. In the following, we briefly review some features of W-pair production in e + e − annihilation in double-pole approximation (DPA), which was worked out for cross-section predictions for LEP2 in different variants by various groups [195,610,[619][620][621][622][623] (see also Ref. [46]).…”

Section: Multiple Resonances In Pole Approximation and Gauge-boson Pa...mentioning

confidence: 87%

Electroweak Radiative Corrections for Collider Physics

Denner,

Dittmaier

2019

Preprint

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Current particle phenomenology is characterized by the spectacular agreement of the predictions of the Standard Model of particle physics (SM) with all results from collider experiments and by the absence of significant signals of non-standard physics, despite the fact that we know that the SM cannot be the ultimate theory of nature. In this situation, confronting theory and experiment with high precision is a promising direction to look for potential traces of physics beyond the SM. On the theory side, the calculation of radiative corrections of the strong and electroweak interactions is at the heart of this task, a field that has seen tremendous conceptual and technical progress in the last decades. This review aims at a coherent introduction to the field of electroweak corrections and tries to fill gaps in the literature between standard textbook knowledge and the current state of the art. The SM and the machinery for its perturbative evaluation are reviewed in detail, putting particular emphasis on renormalization, on one-loop techniques, on modern amplitude methods and tools, on the separation of infrared singularities in real-emission corrections, on electroweak issues connected with hadronic initial or final states in collisions, and on the issue of unstable particles in quantum field theory together with corresponding practical solutions.

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“…For LEP2 accuracy, it was sufficient to include these corrections in the so-called double-pole approximation (DPA), where only the leading term in an expansion about the poles in the two W-boson propagators is taken into account. Different versions of such a DPA have been used in the literature [ 4,5,6,7,8]. Although several Monte Carlo programs exist that include universal corrections, only two event generators, YFSWW [ 5,6] and RacoonWW [ 7,9,10], include non-universal corrections.…”

Section: Introductionmentioning

confidence: 99%

Erratum to “Complete electroweak O(α) corrections to charged-current e+e
Denner
¹
,
Dittmaier
²
,
Roth
³

et al. 2011
Physics Letters B
49
2
103
0
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The complete electroweak O(α) corrections are calculated for the charged-current four-fermion production processes e + e − → ν τ τ + µ −ν µ , udµ −ν µ , and udsc. The calculation is performed using complex gauge-boson masses, supplemented by complex couplings to restore gauge invariance. The evaluation of the occurring one-loop tensor integrals, which include 5-and 6-point functions, requires new techniques. Explicit numerical results are presented for total cross sections in the energy range from the W-pair-production threshold region up to a scattering energy of 2 TeV. A comparison with the predictions based on the "double-pole approximation" (DPA) provided by the generator RacoonWW reveals corrections beyond DPA of < ∼ 0.5% in the energy range 170−300 GeV, in agreement with previous estimates for the intrinsic DPA uncertainty. The difference to the DPA increases to 1−2% for √ s ∼ 1−2 TeV. At threshold, where the DPA becomes unreliable, the full O(α) calculation corrects an improved Born approximation (IBA) by about 1.6%, also consistent with an error estimate of the IBA.

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e+e−→W+W−→4f(+γ) at LEP2

Abstract: The results on e + e − → W + W − → 4f (+γ) obtained by different groups are compared with each other. Differences in the results for the total cross section of up to about 0.6 % are traced back to different ways of implementing the double-pole approximation.

Cited by 11 publications

References 17 publications

Electroweak corrections to charged-current e+e−→4 fermion processes: Technical details and further results

Electroweak corrections to charged-current e+e−→4 fermion processes: Technical details and further results

Electroweak Radiative Corrections for Collider Physics

Erratum to “Complete electroweak O(α) corrections to charged-current e+e
Denner
¹
,
Dittmaier
²
,
Roth
³

et al. 2011
Physics Letters B
49
2
103
0
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e+e−→W+W−→4f(+γ) at LEP2

Abstract: The results on e + e − → W + W − → 4f (+γ) obtained by different groups are compared with each other. Differences in the results for the total cross section of up to about 0.6 % are traced back to different ways of implementing the double-pole approximation.

Cited by 11 publications

References 17 publications

Electroweak corrections to charged-current e+e−→4 fermion processes: Technical details and further results

Electroweak corrections to charged-current e+e−→4 fermion processes: Technical details and further results

Electroweak Radiative Corrections for Collider Physics

Erratum to “Complete electroweak O(α) corrections to charged-current e+eDenner1, Dittmaier2, Roth3 et al. 2011Physics Letters B4921030View full textAdd to dashboardCite

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Erratum to “Complete electroweak O(α) corrections to charged-current e+e
Denner
¹
,
Dittmaier
²
,
Roth
³

et al. 2011
Physics Letters B
49
2
103
0
View full text Add to dashboard Cite