Related papers: Nonperturbative corrections and showering in NLO-m…
Comparisons of experimental data with theoretical predictions for collider processes containing hadronic jets rely on shower Monte Carlo event generators to include corrections to perturbative calculations from hadronization, parton…
We study kinematic effects due to the approximation of on-shell, collinear partons in shower Monte Carlo event generators. We observe that the collinearity approximation, combined with the requirements of energy-momentum conservation, gives…
We review the methods developed for combining the parton shower approximation to QCD with fixed-order perturbation theory, in such a way as to achieve next-to-leading-order (NLO) accuracy for inclusive observables. This has made it possible…
We present predictions for the hadroproduction of $t\bar{t}b\bar{b}$ final states at the LHC with collision energies $\sqrt{s}$ = 8TeV and 14TeV at NLO accuracy matched with parton shower, as obtained with PowHel+ PYTHIA. We quantify the…
Perturbative Quantum Chromodynamics has experienced an impressive progress in the last few years, boosted by the requirements of the LHC experimental program. In this contribution, I briefly review a selection of recent results in QCD and…
We present a selection of results from our recent study of $pp\to t\bar{t}W^\pm$ production matched to partons showers at NLO QCD at the LHC. Theoretical predictions are obtained at perturbative orders $\mathcal{O}(\alpha_s^3\alpha)$ and…
To explore the interplay of NLO matching and next-to-leading logarithmic (NLL) parton showers, we consider the simplest case of $\gamma^*$ and Higgs-boson decays to $q\bar q$ and $gg$ respectively. Not only should shower NLL accuracy be…
We discuss current issues associated with the dependence of jet distributions at the LHC on the behavior of QCD parton showers for high rapidities.
We present a process-independent technique to consistently combine next-to-leading order parton-level calculations of varying jet multiplicity and parton showers. Double counting is avoided by means of a modified truncated shower scheme.…
Higher order calculations are necessary to predict and describe measurements in high energy collider physics. In recent years multiple approaches to combine multiple next-to-leading (NLO) order corrections with parton showers had been…
In this publication, uncertainties in and differences between the MC@NLO and POWHEG methods for matching next-to-leading order QCD calculations with parton showers are discussed. Implementations of both algorithms within the event generator…
We study the medium modification of jets correlated with large transverse momentum photons at the LHC via a transport and perturbative QCD hybrid model which incorporates the contributions from both elastic collisions and radiative energy…
We are developing a consistent method to combine tree-level event generators for hadron collision interactions with those including one additional QCD radiation from the initial-state partons, based on the limited leading-log (LLL)…
The merging of matrix elements and parton showers is an established calculational tool for the description of multi-jet final states at hadron colliders. These methods have recently been promoted to next-to-leading order accuracy in the…
This lecture discusses the physics implemented by Monte Carlo event generators for hadron colliders. It details the construction of parton showers and the matching of parton showers to fixed-order calculations at higher orders in…
We consider a model of transverse momentum production in which non-perturbative smearing takes place throughout the perturbative evolution, by a simple modification to an initial state parton shower algorithm. Using this as the important…
We present an algorithm to combine multiple matrix elements at LO and NLO with a parton shower. We build on the unitarized merging paradigm. The inclusion of higher orders and multiplicities reduce the scale uncertainties for observables…
We discuss non-perturbative QCD contributions to jet observables, computing their dependence on the jet radius R, and on the colour and transverse momentum of the parton initiating the jet. We show, using analytic QCD models of power…
In these proceedings we investigate the impact of offshell and non-resonant contributions to kinematic distributions in $t\bar{t}$ final states by comparing several next-to-leading-order~(NLO) + parton shower (PS) generators which differ in…
In this talk we discuss recent results on the impact of LHC jet data on global fits of parton distribution functions using theoretical predictions at NNLO in QCD supplemented by electroweak (EW) corrections.