One-loop Singular Behaviour of QCD and SUSY QCD Amplitudes with Massive Partons

By S. Catani, Stefan Dittmaier, Z. Trocsanyi. 2000

201 citations recorded by the source corpus.

We discuss the structure of infrared and ultraviolet singularities in on-shell QCD and supersymmetric QCD amplitudes at one-loop order. Previous results, valid for massless partons, are extended to the case of massive partons. Using dimensional regularization, we present a general factorization formula that controls both the singular ǫ-poles and the logarithmic contributions that become singular for vanishing masses. We introduce generalized Altarelli–Parisi splitting functions and discuss their relations with the singular terms in the amplitudes. The dependence on the regularization scheme is also considered.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/f3dbb3d3db2bd46a34ea1eed0233a6475d4dfe13

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In Nuclear and High Energy Physics

Citations in the corpus

Soft photon radiation in particle decays in SHERPA (2008, background): “Since masses are to be taken fully into account the quasi-collinear limit defined in [17,18] replaces the more familiar collinear one.”
Erratum: On the structure of infrared singularities of gauge-theory amplitudes (2009, methodology): “Furthermore, by combining our results with methods developed in [86–90], which relate the singularities of massive and massless amplitudes, our formalism can be generalized to the massive case.”
QCD matrix elements and truncated showers (2009, background): “Equation (34) corresponds to the leading term of the massive Altarelli-Parisi splitting function for z → 1 [45].”
NLO matrix elements and truncated showers (2010, unknown): “ln −kµ ⊥ . (30) A relation for p2 ij is immediately obtained, p2 ij −m 2 i −m 2 j = k2 ⊥ z(1−z) − 1−z z m2 i − z 1−z m2 j . (31) Taking the quasi-collinear limit amounts to the simultaneous rescaling [45] k⊥ →λk⊥ , mi →λmi , mj →λmj , mij →λmij . (32) Then, 2pipj → λ 2(p2 ij −mi −m2j) and, independe”
NLO QCD matrix elements + parton showers in e+e− → hadrons (2012, background): “By incorporating full colour information in D(A), it is easily possible to obtain the exact same singularity structure as in the real-emission matrix element [21, 22].”
Event generation with SHERPA 1.1 (2008, background): “n brather than aaligned along the beam axis and ˆs→ˆs/ ¯z. The Altarelli–Parisi splitting functions, Pab(z), are taken in the quasi-collinear limit and include mass eﬀects of the emitting parton, cf. [87], Pqq(z) = CF 1 + z2 1−z −2µ2 qg , Pgq(z) = TR z2 + (1 −z)2 −µ2 qq¯ , Pgg(z) = CA z 1 −z + 1 ”
GoSam-2.0: a tool for automated one-loop calculations within the Standard Model and beyond (2014, methodology): “A first commonly used approach relies on the comparison between the numerical values of the infrared pole coefficients computed by the automated tool with their known analytic results dictated by the universal behaviour of the infrared singularities [66].”
Electroweak radiative corrections for collider physics (2019, background): “[400] to predict the complete IR structure of virtual NLO QCD corrections in DR or MR for any generic process.”