15 research outputs found
Light fermionic NNLO QCD corrections to top-antitop production in the quark-antiquark channel
We present the NNLO corrections to top pair production in the quark-antiquark
channel proportional to the number of light quark flavors . While the
double real corrections were derived previously, here we compute the
real-virtual and virtual-virtual contributions in this partonic channel. Using
the antenna subtraction formalism, we show that the subtraction terms correctly
approximate the real-virtual contributions in all their infrared limits.
Combined with the integrated forms of the double real and real-virtual
subtraction terms, we show analytically that the explicit infrared poles cancel
at the real-virtual and virtual-virtual levels respectively, thereby
demonstrating the validity of the massive extension of the NNLO antenna
formalism. These NNLO corrections are implemented in a Monte Carlo parton level
generator providing full kinematical information on an event-by event basis.
With this program, NNLO differential distributions in the form of binned
histograms are obtained and presented here.Comment: 42 pages, 8 figure
Single-inclusive jet production in electron-nucleon collisions through next-to-next-to-leading order in perturbative QCD
We compute the perturbative corrections to
inclusive jet production in electron-nucleon collisions. This process is of
particular interest to the physics program of a future Electron Ion Collider
(EIC). We include all relevant partonic processes, including deep-inelastic
scattering contributions, photon-initiated corrections, and parton-parton
scattering terms that first appear at this order. Upon integration over the
final-state hadronic phase space we validate our results for the deep-inelastic
corrections against the known next-to-next-to-leading order (NNLO) structure
functions. Our calculation uses the -jettiness subtraction scheme for
performing higher-order computations, and allows for a completely differential
description of the deep-inelastic scattering process. We describe the
application of this method to inclusive jet production in detail, and present
phenomenological results for the proposed EIC. The NNLO corrections have a
non-trivial dependence on the jet kinematics and arise from an intricate
interplay between all contributing partonic channels.Comment: 9 pages, 4 figure
Top quark pair production at NNLO in the quark-antiquark channel
We present the derivation of the NNLO two-parton final state contributions to
top pair production in the quark-antiquark channel proportionnal to the leading
colour factor . Together with the three and four-parton NNLO
contributions presented in a previous publication, this enables us to complete
the phenomenologically most important NNLO corrections to top pair
hadro-production in this channel. We derive this two-parton contribution using
the massive extension of the NNLO antenna subtraction formalism and implement
those corrections in a parton-level event generator providing full kinematical
information on all final state particles. In addition, we also derive the heavy
quark contributions proportional to . Combining the new leading-colour and
heavy quark contributions together with the light quark contributions derived
previously, we present NNLO differential distributions for LHC and Tevatron. We
also compute the differential top quark forward-backward asymmetry at Tevatron
and find that our results are in good agreement with the measurements by the D0
collaboration.Comment: 48 pages, 9 figure
Antenna subtraction for the production of heavy particles at hadron colliders
The antenna subtraction method developed originally for the computation of
higher order corrections to jet observables from a colourless initial state is
extended for hadron collider processes involving a pair of massive particles
and jets in the final state at the next-to-leading order (NLO) level. Due to
the presence of coloured initial states, the subtraction terms need to be
divided into three categories (final-final, initial-final and initial-initial).
In this paper, we outline their construction and derive the necessary
ingredients: phase space factorisation, antenna functions and also integrated
antennae, including the effects of massive final states in all of those
building parts. As a first application, we explicitly construct the
colour-ordered real radiation and the corresponding antenna subtraction terms
required at NLO for the production of a top quark pair and for the production
of a top quark pair in association with a hard jet. The latter constitutes an
essential ingredient for the computation of the hadronic production of a
top-antitop pair at NNLO.Comment: 80 pages, LaTeX, version accepted for publication in JHE
NNLO QCD subtraction for top-antitop production in the channel
We present the computation of the double real and real-virtual contributions
to top-antitop pair production in the quark-antiquark channel at leading
colour. The amplitudes contributing to the
real-virtual part are computed with OpenLoops, and their numerical stability in
the soft and collinear regions is found to be sufficiently high to perform a
realistic NNLO calculation in double precision. The subtraction terms required
at real-real and real-virtual levels are constructed within the antenna
subtraction formalism extended to deal with the presence of coloured massive
final state particles. We show that those subtraction terms approximate the
real-real and real-virtual matrix elements in all their singular limits.Comment: 54 pages, 10 figure
Antenna subtraction with massive fermions at NNLO: Double real initial-final configurations
We derive the integrated forms of specific initial-final tree-level
four-parton antenna functions involving a massless initial-state parton and a
massive final-state fermion as hard radiators. These antennae are needed in the
subtraction terms required to evaluate the double real corrections to
hadronic production at the NNLO level stemming from the partonic
processes and .Comment: 24 pages, 1 figure, 1 Mathematica file attache
Double real radiation corrections to production at the LHC: the all-fermion processes
We present the double real radiation corrections to the hadronic
production stemming from partonic processes with fermions only. For this
purpose, we extend the NNLO antenna subtraction formalism developed originally
for the computation of jet observables in annihilation to include the
evaluation of hadronic observables involving a massive pair of particles. In
all partonic processes, we checked the validity of our subtraction terms given
for leading and subleading colour contributions numerically by showing that the
ratio between real radiation matrix elements and subtraction terms approaches
unity in all single and double unresolved configurations.Comment: 68 pages, 9 figure