The double-soft integral for an arbitrary angle between hard radiators
EUROPEAN PHYSICAL JOURNAL C 78:8 (2018) ARTN 687
NNLO QCD corrections to associated W H production and H → b ¯ b decay
Physical Review D American Physical Society 97:7 (2018) 74022
Abstract:
We present a computation of the next-to-next-to-leading-order (NNLO) QCD corrections to the production of a Higgs boson in association with a W boson at the LHC and the subsequent decay of the Higgs boson into a bb¯ pair, treating the b quarks as massless. We consider various kinematic distributions and find significant corrections to observables that resolve the Higgs decay products. We also find that a cut on the transverse momentum of the W boson, important for experimental analyses, may have a significant impact on kinematic distributions and radiative corrections. We show that some of these effects can be adequately described by simulating QCD radiation in Higgs boson decays to b quarks using parton showers. We also describe contributions to Higgs decay to a bb¯ pair that first appear at NNLO and that were not considered in previous fully differential computations. The calculation of NNLO QCD corrections to production and decay sub-processes is carried out within the nested soft-collinear subtraction scheme presented by some of us earlier this year. We demonstrate that this subtraction scheme performs very well, allowing a computation of the coefficient of the second-order QCD corrections at the level of a few per mill.A journey through small-x resummation
Chapter in From My Vast Repertoire...: Guido Altarelli's Legacy, (2018) 173-204
Abstract:
The study of QCD in the high-energy regime where Q is the typical scale of the process under consideration and s is the centreof-mass energy, is a complex and fascinating one. On the one hand, this region is perturbative since Q2 R2 QCD. On the other hand, subtle all-order effects must be taken into account for its proper description. Analyses of this region shed more light on many interesting aspects of QCD, from more formal ones — like for instance a quantum field theory approach to Regge theory (see e.g. [Gribov et al. (1983); Lipatov (1997)]) — to more phenomenological ones — like for example the onset of parton saturation in proton and heavy–ion collisions (see e.g. [Mueller (2001)]) or the interplay between the Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGLAP) [Altarelli and Parisi (1977); Gribov and Lipatov (1972a); Dokshitzer (1977)] and Balitsky–Fadin–Kuraev–Lipatov (BFKL) [Lipatov (1976); Fadin et al. (1975); Kuraev et al. (1977); Balitsky and Lipatov (1978)] evolution and its implications for the physics of parton distribution functions (PDFs), see e.g. [Forte et al. (2009)].Nested soft-collinear subtractions in NNLO QCD computations.
The European physical journal. C, Particles and fields 77:4 (2017) 248-248
Abstract:
We discuss a modification of the next-to-next-to-leading order (NNLO) subtraction scheme based on the residue-improved sector decomposition that reduces the number of double-real emission sectors from five to four. In particular, a sector where energies and angles of unresolved particles vanish in a correlated fashion is redundant and can be discarded. This simple observation allows us to formulate a transparent iterative subtraction procedure for double-real emission contributions, to demonstrate the cancellation of soft and collinear singularities in an explicit and (almost) process-independent way and to write the result of a NNLO calculation in terms of quantities that can be computed in four space-time dimensions. We illustrate this procedure explicitly in the simple case of [Formula: see text] gluonic corrections to the Drell-Yan process of [Formula: see text] annihilation into a lepton pair. We show that this framework leads to fast and numerically stable computation of QCD corrections.ZZ production in gluon fusion at NLO matched to parton shower
Physical Review D American Physical Society (APS) 95:3 (2017) 034042