87 research outputs found
A numerical formulation of resummation in effective field theory
In this article we show how the resummation of infrared and collinear
logarithms within Soft-Collinear Effective Theory (SCET) can be formulated in a
way that makes it suitable for a Monte-Carlo implementation. This is done by
applying the techniques developed for automated resummation using the branching
formalism, which have resulted in the general resummation approach CAESAR/ARES.
This work builds a connection between the two resummation approaches, and paves
the way to automated resummation in SCET. As a case study we consider the
resummation of the thrust distribution in electron-positron collisions at
next-to-leading logarithm (NLL). However, the results presented here are easily
generalizable to more complicated observables and processes as well as to
higher orders in the logarithmic accuracy.Comment: 47 page
Constraining Light-Quark Yukawa Couplings from Higgs Distributions
We propose a novel strategy to constrain the bottom and charm Yukawa
couplings by exploiting LHC measurements of transverse momentum distributions
in Higgs production. Our method does not rely on the reconstruction of
exclusive final states or heavy-flavour tagging. Compared to other proposals it
leads to an enhanced sensitivity to the Yukawa couplings due to distortions of
the differential Higgs spectra from emissions which either probe quark loops or
are associated to quark-initiated production. We derive constraints using data
from LHC Run I, and we explore the prospects of our method at future LHC runs.
Finally, we comment on the possibility of bounding the strange Yukawa coupling.Comment: Added analysis of the Higgs transverse momentum distribution. Version
published in Physical Review Letter
Higgs and Z-boson production with a jet veto
We derive first next-to-next-to-leading logarithmic resummations for jet-veto
efficiencies in Higgs and Z-boson production at hadron colliders. Matching with
next-to-next-to-leading order results allows us to provide a range of
phenomenological predictions for the LHC, including cross-section results,
detailed uncertainty estimates and comparisons to current widely-used tools.Comment: 6 pages and 2 figures, plus 8 pages and 2 figures of supplemental
material. v2 contains additional references and small textual change
Momentum-space resummation for transverse observables and the Higgs at NLL+NNLO
We present an approach to the momentum-space resummation of global, recursive
infrared and collinear safe observables featuring kinematic zeros away from the
Sudakov limit. In the hadro-production of a generic colour singlet, we consider
the family of inclusive observables which do not depend on the rapidity of the
radiation, prime examples being the transverse momentum of the singlet, and
in Drell-Yan pair production. We derive a resummation formula valid up
to next-to-next-to-next-to-leading-logaritmic accuracy for the considered
observables. This formula reduces exactly to the customary resummation
performed in impact-parameter space in the known cases, and it also predicts
the correct power-behaved scaling of the cross section in the limit of small
value of the observable. We show how this formalism is efficiently implemented
by means of Monte Carlo techniques in a fully exclusive generator that allows
one to apply arbitrary cuts on the Born variables for any colour singlet, as
well as to automatically match the resummed results to fixed-order
calculations. As a phenomenological application, we present state-of-the-art
predictions for the Higgs-boson transverse-momentum spectrum at the LHC at
next-to-next-to-next-to-leading-logarithmic accuracy matched to fixed
next-to-next-to-leading order.Comment: Journal versio
Merging WW and WW+jet with MINLO
We present a simulation program for the production of a pair of W bosons in
association with a jet, that can be used in conjunction with general-purpose
shower Monte Carlo generators, according to the POWHEG method. We have further
adapted and implemented the MINLO' method on top of the NLO calculation
underlying our WW+jet generator. Thus, the resulting simulation achieves NLO
accuracy not only for inclusive distributions in WW+jet production but also WW
production, i.e. when the associated jet is not resolved, without the
introduction of any unphysical merging scale. This work represents the first
extension of the MINLO' method, in its original form, to the case of a genuine
underlying 2->2 process, with non-trivial virtual corrections.Comment: 22 pages, 9 figure
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