Factorization and Resummation for Massive Quark Effects in Exclusive Drell-Yan

Mar 28, 2017
67 pages
Published in:
  • JHEP 08 (2017) 114
  • Published: Aug 25, 2017
e-Print:
Report number:
  • DESY-16-199,
  • UWTHPH-2017-3,
  • HU-EP-16-42

Citations per year

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Abstract: (Springer)
Exclusive differential spectra in color-singlet processes at hadron colliders are benchmark observables that have been studied to high precision in theory and experiment. We present an effective-theory framework utilizing soft-collinear effective theory to incorporate massive (bottom) quark effects into resummed differential distributions, accounting for both heavy-quark initiated primary contributions to the hard scattering process as well as secondary effects from gluons splitting into heavy-quark pairs. To be specific, we focus on the Drell-Yan process and consider the vector-boson transverse momentum, qT_{T} , and beam thrust, T \mathcal{T} , as examples of exclusive observables. The theoretical description depends on the hierarchy between the hard, mass, and the qT_{T} (or T \mathcal{T} ) scales, ranging from the decoupling limit qT_{T} ≪ m to the massless limit m ≪ qT_{T} . The phenomenologically relevant intermediate regime m ∼ qT_{T} requires in particular quark-mass dependent beam and soft functions. We calculate all ingredients for the description of primary and secondary mass effects required at NNLL^{′} resummation order (combining NNLL evolution with NNLO boundary conditions) for qT_{T} and T \mathcal{T} in all relevant hierarchies. For the qT_{T} distribution the rapidity divergences are different from the massless case and we discuss features of the resulting rapidity evolution. Our results will allow for a detailed investigation of quark-mass effects in the ratio of W and Z boson spectra at small qT_{T} , which is important for the precision measurement of the W-boson mass at the LHC.
Note:
  • 42 pages + appendices, 21 figures; v2: journal version
  • Jets
  • QCD Phenomenology
  • soft collinear effective theory
  • Drell-Yan process
  • vector boson: transverse momentum
  • transverse momentum: momentum spectrum
  • heavy quark: pair production
  • heavy quark: mass
  • mass: effect
  • gluon: splitting