Related papers: QCD matrix elements and truncated showers
We present hadron-level predictions from the Monte Carlo generator Cascade and parton level calculations of open b quark, b-flavored hadron and inclusive b-jet production in the framework of the kt-factorization QCD approach for the LHC…
In the algorithm presented here, the ME+PS approach to merge samples of tree-level matrix elements into inclusive event samples is combined with the POWHEG method, which includes exact next-to-leading order matrix elements in the parton…
First, we present a combined analysis of ${\rm p}{\rm p} \to \mu^+ \nu_\mu {\rm e}^- \bar \nu_{\rm e}$ and ${\rm p}{\rm p} \to \mu^+ \nu_\mu {\rm e}^- \bar \nu_{\rm e} {\rm j}$ at next-to-leading order, including both QCD and electroweak…
We present first results from a new parton shower event generator, Deductor. Anticipating a need for an improved treatment of parton color and spin, the structure of the generator is based on the quantum density matrix in color and spin…
The method to merge matrix elements for multi particle production and parton showers in electron-positron annihilations and hadronic collisions and its implementation into the new event generator SHERPA is described in detail. Examples…
We compare fixed order and parton shower matched predictions for the process ${pp\rightarrow \ell^+\nu_{\ell} \ell^-\bar{\nu}_{\ell} \ell^{\pm}{\nu}_{\ell} b\bar{b}+X}$ at NLO in QCD, including the orders $\mathcal{O}(\alpha_s^3\alpha^6)$…
We present in detail a calculation of the next-to-leading order QCD corrections to the process $e^+e^-\to 3$ jets with massive quarks. To isolate the soft and collinear divergencies of the four parton matrix elements, we modify the phase…
Within the framework of the constituent quark model, it is shown that the single hadron fragmentation function of a parton can be expressed as a convolution of shower diquark or triquark distribution function and quark recombination…
An earlier developed $k_T$-factorization framework to calculate the associated prompt photon and hadronic jets production cross sections at high energies is extended now to the electron-proton deep inelastic scattering. The proposed method…
We consider the impact of varying alpha_s choices (and scales) on each side of the so-called "matching scale" in MLM-matched matrix-element + parton-shower predictions of collider observables. We explain how inconsistent prescriptions can…
In this talk I gave a brief summary of leading order, next-to-leading order and shower calculations. I discussed the main ideas and approximations of the shower algorithms and the related matching schemes. I tried to focus on QCD issues and…
We consider idealized parton shower event generators that treat parton spin and color exactly, leaving aside the choice of practical approximations for spin and color. We investigate how the structure of such a parton shower generator is…
A new Monte Carlo model is proposed for radiative corrections to Bhabha scattering by extending QEDPS developed for multi-photon emission in muon pair production in $e^+e^-$ annihilation. This is the QED version of the model known as parton…
Presently available perturbative QCD calculations combining hard process matrix element with the Parton Shower Monte Carlo programs feature hard process matrix element calculated often beyond the leading order (LO), that is including…
We propose a novel technique for the combination of multi-jet merged simulations in the five-flavor scheme with calculations for the production of b-quark associated final states in the four-flavor scheme. We show the equivalence of our…
We have previously described a mathematical formulation for a parton shower based on the approximation of strongly ordered virtualities of successive parton splittings. Quantum interference, including interference among different color and…
We extend the GENEVA Monte Carlo framework using the transverse momentum of a colour-singlet system as the resolution variable. This allows us to use next-to-next-to-next-to leading logarithm (N$^3$LL) resummation via the \radish formalism…
We present a conceptually new framework for describing jet evolution in the dense medium produced in ultra-relativistic nucleus-nucleus collisions using perturbative QCD and its implementation into the Monte Carlo event generator JEWEL. The…
A parton shower method for the photonic radiative correction is applied to the single W-boson production processes. The energy scale for the evolution of the parton shower is determined so that the correct soft-photon emission is…
We derive a new method for initial-state collinear showering in Monte-Carlo event generators which is based on the use of unintegrated parton correlation functions. Combined with a previously derived method for final-state showering, the…