The Dipole Formalism for Next-to-Leading Order QCD Calculations with Massive Partons

By S. Catani, Stefan Dittmaier, M. Seymour, Z. Trocsanyi. 2002

559 citations recorded by the source corpus.

Abstract The dipole subtraction method for calculating next-to-leading order corrections in QCD was originally only formulated for massless partons. In this paper we extend its definition to include massive partons, namely, quarks, squarks and gluinos. We pay particular attention to the quasi-collinear region, which gives rise to terms that are enhanced by logarithms of the parton masses, M . By ensuring that our subtraction cross section matches the exact real cross section in all quasi-collinear regions we achieve uniform convergence both for hard scales Q ∼ M and Q ⪢ M . Moreover, taking the masses to zero, we exactly reproduce the previously-calculated massless results. We give all the analytical formulae necessary to construct a numerical program to evaluate the next-to-leading order QCD corrections to arbitrary observables in an arbitrary process.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/c9e58480c478b1cdb5ad4141b530c211845d5bd2

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Citations in the corpus

Fully differential NNLO computations with MATRIX (2017, methodology): “cluster_submit_line[1-99] Lines in cluster submit file to add cluster-specific options.”
Next-to-leading-order electroweak corrections to the production of four charged leptons at the LHC (2016, methodology): “The phase-space integration has been carried out with a multi-channel Monte Carlo integrator with an implementation of the dipole-subtraction formalism [50, 51, 53, 56] for collinear-safe and collinear-unsafe observables.”
Electroweak radiative corrections for collider physics (2019, background): “[54, 370] differ in the massless limit, is the bremsstrahlung case of final–final type.”
NLO matrix elements and truncated showers (2010, background): “Like in [44] the discussion is restricted to a dipole-like factorisation [45, 46].”
Reweighting QCD matrix-element and parton-shower calculations (2016, methodology): “The variables yi j,k , z̃i , xi j,a , x jk,a , x j,ab, u j and v j are defined in [23,36,37]”
QCD matrix elements and truncated showers (2009, methodology): “It relies on the factorisation of real-emission matrix elements in the CS subtraction framework [55, 43].”
HatHor for single top-quark production: Updated predictions and uncertainty estimates for single top-quark production in hadronic collisions (2014, methodology): “To achieve this cancellation, the CataniSeymour subtraction formalism [47, 48] is employed in MCFM, i.”
Soft photon radiation in particle decays in SHERPA (2008, background): “The massive dipole splitting functions are needed for the calculation of the approximation to the infrared subtracted single hard photon emission matrix element ˜ β 1 . They are taken directly from [17] for spin- 1 emitters and are generalised from [ 19 ] for all other cases.”
NLO electroweak automation and precise predictions for W + multijet production at the LHC (2014, methodology): “Both Monte Carlo tools, Munich and Sherpa, employ the dipole subtraction scheme [64, 65] for the cancellation of infrared singularities.”
Hadronic top-quark pair-production with one jet and parton showering (2011, background): “Also note that the computation of [7, 8] has employed dipole subtraction with massive partons [35] for the cancellation of the soft and collinear divergences between the real and virtual contributions.”
N-jettiness subtractions for NNLO QCD calculations (2015, background): “The goal of typical NLO subtraction schemes like FKS subtractions [1–3] or CS subtractions [4–6] is to construct subtraction terms that reproduce the correct IR-singular behaviour of the full real-emission amplitude point-by-point in phase space.”