Feyn Calc - Computer-algebraic calculation of Feynman amplitudes

Mertig, R.; Böhm, M.; Denner, Ansgar

doi:10.1016/0010-4655(91)90130-d

Cited by 1,398 publications

(1,204 citation statements)

References 7 publications

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“…Feynman diagrams have been drawn with the packages Axodraw [43] and Jaxodraw [44]. We acknowledge the use of the computer programs FORM [45] and FeynCalc [46] for some parts of the calculation.…”

Section: Acknowledgmentmentioning

confidence: 99%

Electroweak non-resonant NLO corrections to in the resonance region

2010

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We analyse subleading electroweak effects in the top anti-top resonance production region in e + e − collisions which arise due to the decay of the top and anti-top quarks into the W + W − bb final state. These are NLO corrections adopting the nonrelativistic power counting v ∼ α s ∼ √ α EW . In contrast to the QCD corrections which have been calculated (almost) up to NNNLO, the parametrically larger NLO electroweak contributions have not been completely known so far, but are mandatory for the required accuracy at a future linear collider. The missing parts of these NLO contributions arise from matching coefficients of non-resonant productiondecay operators in unstable-particle effective theory which correspond to off-shell top production and decay and other non-resonant irreducible background processes to tt production. We consider the total cross section of the e + e − → W + W − bb process and additionally implement cuts on the invariant masses of the W + b and W −b pairs.

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Section: Acknowledgmentmentioning

confidence: 99%

Electroweak non-resonant NLO corrections to in the resonance region

2010

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“…However, here we depart from the "correct" matching procedure and omit the factor ̟ −1/2 , since it was already included in Section 3.1 (see discussion after (28)). The diagrams for the e − (p 1 )e + (p 2 ) → W − (k 1 )W + (k 2 ) scattering process are generated with FeynArts [37] and the algebra is performed with FeynCalc [38]. At one loop, there are 65 two-point diagrams, 84 three-point diagrams and 31 four-point diagrams (generically counting up-type quarks, down type quarks, leptons and neutrinos), some of which are shown in Figure 7.…”

Section: Production Verticesmentioning

confidence: 99%

Four-fermion production near the W pair-production threshold

et al. 2008

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We perform a dedicated study of the four-fermion production process e − e + → µ −ν µ ud X near the W pair-production threshold in view of the importance of this process for a precise measurement of the W boson mass. Accurate theoretical predictions for this process require a systematic treatment of finite-width effects. We use unstable-particle effective field theory (EFT) to perform an expansion in the coupling constants, Γ W /M W , and the non-relativistic velocity v of the W boson up to next-to-leading order in Γ W /M W ∼ α ew ∼ v 2 . We find that the dominant theoretical uncertainty in M W is currently due to an incomplete treatment of initial-state radiation. The remaining uncertainty of the NLO EFT calculation translates into δM W ≈ 10 -15 MeV, and to about 5 MeV with additional input from the NLO four-fermion calculation in the full theory.

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“…(9), as shown in Fig.1. We have used the software packages FeynArts [19] to draw the Feynman diagrams and generate the corresponding Feynman amplitudes, then used FeynCalc [20] to calculate these Feynman amplitudes. It is easy to get the analytical result of δV ij since the quark's self-energy functions at one-loop level are simple.…”

Section: One-loop Renormalization Of Ckm Matrixmentioning

confidence: 99%

Renormalization of the Cabibbo–Kobayashi–Maskawa matrix at one-loop level

Zhou

2004

J. Phys. G: Nucl. Part. Phys.

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We have investigated the present renormalization prescriptions of Cabibbo-Kobayashi-Maskawa (CKM) matrix at one-loop level. We emphasize at one prescription which is formulated with reference to the case of no mixing of quark's generations and point out that it doesn't make the physical amplitude involving quark mixing ultraviolet finite. We then propose a revised prescription to solve this problem and simultaneously keep the unitarity of the CKM matrix. Through explicit calculations we also prove that in order to keep the CKM matrix gauge independent the unitarity of the CKM matrix must be preserved.11.10. Gh, 12.15.Lk, 12.15.Hh

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Feyn Calc - Computer-algebraic calculation of Feynman amplitudes

Cited by 1,398 publications

References 7 publications

Electroweak non-resonant NLO corrections to in the resonance region

Electroweak non-resonant NLO corrections to in the resonance region

Four-fermion production near the W pair-production threshold

Renormalization of the Cabibbo–Kobayashi–Maskawa matrix at one-loop level

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