Interference radiative phenomena in the production of heavy unstable particles

Fadin, V.S.; Khoze, V. A.; Martin, A.

doi:10.1103/physrevd.49.2247

Cited by 111 publications

(224 citation statements)

References 13 publications

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“…Note that (mm2) is not a double-counting of the Coulomb-exchange diagram in Figure 9, since the two diagrams refer to different loop momentum regions. It is well known that for the process e − e + → W − W + → f 1f2 f 3f4 the soft-photon corrections related to the final state cancel for the inclusive cross section [42,43]. The diagrams of type (im) in Figure 10 cancel pairwise when the sum over incoming positrons and electrons is performed.…”

Section: Soft-photon Correctionsmentioning

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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Section: Soft-photon Correctionsmentioning

confidence: 99%

Four-fermion production near the W pair-production threshold

et al. 2008

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“…Even though there is an effective theory framework available for systematically taking into account these corrections [42], a full explicit calculation of electroweak effects at NNLO is still lacking. If we are interested in the total cross section only, the situation is somewhat simpler, since the non-factorizable corrections cancel [43], and the replacement E → E + iΓ t becomes correct with NLO accuracy. Furthermore, some of the electroweak corrections have be taken into account by including them in the matching coefficients [44].…”

Section: The Case Of the Top Quarkmentioning

confidence: 99%

“…(7), are to be evaluated as indicated in Eqs. (42) and (43). Using the threshold expansion [11], the Fourier transform of the leading order Green function can be computed as the sum of all ladder diagrams with the exchange of potential gluons between the heavy quarks and can be written as…”

Section: Potentialmentioning

confidence: 99%

Heavy quark pair production near threshold with potential non-relativistic QCD

Pineda

Signer²

2007

Nuclear Physics B

106

133

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We study the effect of the resummation of logarithms for tt production near threshold and inclusive electromagnetic decays of heavy quarkonium. This analysis is complete at next-to-next-to-leading order and includes the full resummation of logarithms at next-to-leading-logarithmic accuracy and some partial contributions at next-to-next-to-leading logarithmic accuracy. Compared with fixed-order computations at next-to-next-to-leading order the scale dependence and convergence of the perturbative series is greatly improved for both the position of the peak and the normalization of the total cross section. Nevertheless, we identify a possible source of large scale dependence in the result. At present we estimate the remaining theoretical uncertainty of the normalization of the total cross section to be of the order of 10% and for the position of the peak of the order of 100 MeV.

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“…Indeed, comparison between purely hadronic decays W + W − → q 1q2 + q 3q4 and semileptonic decays W + W − → q 1q2 + ℓν with the same kinematics could be a sensitive probe of the confinement dynamics. However, the current consensus is that large interference effects are unlikely to be generated during the perturbative phase [2,3,4] of parton shower development that follows immediately on the electroweak decays of the W ± , but the question remains open whether significant interference effects might appear during the subsequent non-perturbative hadronization phase [5,6,7,8,9,10]. These might result either from effects on the parton-tohadron conversion process -due to the fact that the decay products of the W ± overlap in space and time, hadronic clusters might be formed by coalescence of partons from the W + and W − showers, a possibility we term exogamy -or from the statistics of final-state hadrons -most importantly Bose-Einstein correlations among pions.…”

mentioning

confidence: 99%

Signatures of parton exogamy in e+e− → W+W− → hadrons

Ellis

Geiger

1997

Physics Letters B

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We propose possible signatures of 'exogamous' combinations between partons in the different W + and W − hadron showers in e + e − → W + W − events with purely hadronic final states. Within the space-time model for hadronic shower development that we have proposed previously, we find a possible difference of about 10 % between the mean hadronic multiplicity in such purely hadronic final states and twice the hadronic multiplicity in events in which one W ± decays hadronically and the other leptonically, i.e., < N had (2W ) > = 2 < N had (W ) >, associated with the formation of hadronic clusters by 'exogamous' pairs of partons. We discuss the dependence of this possible difference in multiplicity on the center-of-mass energy, on the hadron momenta, and on the angular separation between the W ± dijets. If it were observed, any such multiplicity difference would indicate that the W ± do not hadronize independently, and hence raise questions about the accuracy with which the W ± mass could be determined from purely hadronic final states.

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Interference radiative phenomena in the production of heavy unstable particles

Cited by 111 publications

References 13 publications

Four-fermion production near the W pair-production threshold

Four-fermion production near the W pair-production threshold

Heavy quark pair production near threshold with potential non-relativistic QCD

Signatures of parton exogamy in e+e− → W+W− → hadrons

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