Related papers: The Four-Jet Rate in e+e- Annihilation
The process e+ e- -> 3 jets offers the opportunity to measure the strong coupling constant. For an accurate determination, precise theoretical calculations are necessary. I will give an overview on the status of the next-to-next-to-leading…
Recent results on QCD studies in e+e- annihilations at LEP are presented. Data recorded by the LEP experiments at centre-of-mass energies between 91.2 to 206 GeV are included. The main topic is the measurement of alpha_s from event-shape…
We present the first explicit formulae for the complete set of one-loop helicity amplitudes necessary for computing next-to-leading order corrections for e^+ e^- annihilation into four jets, for W, Z or Drell-Yan production in association…
A study of perturbative QCD calculations combined with power corrections to model hadronisation effects is presented. The QCD predictions are fitted to differential distributions and mean values of event shape observables measured in e+e-…
Jet broadening is an event-shape variable probing the transverse momenta of particles inside jets. It has been measured precisely in e+e- annihilations and is used to extract the strong coupling constant. The factorization of the associated…
The resummed differential thrust rate in e+e- annihilation is calculated using Soft-Collinear Effective Theory (SCET). The resulting distribution in the two-jet region T~1 is found to agree with the corresponding expression derived by the…
We consider the dijet cross section in $e^+ e^-$ annihilation using the Georgi jet algorithm, or the maximizing jet algorithm. The cross section is factorized into the hard, collinear and soft parts. Each factorized function is computed to…
We study electron-positron annihilations into six jets at the parton level in perturbative Quantum Chromo-Dynamics. We use helicity amplitude methods. Results are presented for the case of the Durham and Cambridge jet clustering algorithms…
Three-jet event-shape distributions can be exploited to investigate the dependence of hadronisation effects on the colour and the geometry of the underlying hard event. We present here the first comparison of data in e+e- annihilation and…
Data from e+e- annihilation into hadrons collected by the JADE experiment at centre-of-mass energies between 14 GeV and 44 GeV were used to study moments of event shape distributions. The data were compared with Monte Carlo models and with…
We show how the resummation of large logarithms can be incorporated into the method of effective charges. As an example, we apply this approach to the event shape variables thrust and heavy jet mass in e+e- annihilation. We find that,…
The inclusive four-particle phase space integral of any $1\to 4$ matrix element in massless QCD contains divergences due to the soft and collinear emission of up to two particles in the final state. We show that any term appearing in this…
The reaction $e^+e^-$ annihilation into three jets was recently computed for massive quarks at next-to-leading order in perturbative QCD. We discuss some results of our calculation for b jets produced at the Z resonance.
We compute the invariant mass of dijets produced in $e^+ e^-$ annihilation processes up to four loops in perturbation theory for both anti-$k_t$ and $k_t$ jet algorithms. The calculations, performed within the eikonal approximation and…
We propose a framework for the implementation of a subtraction formalism at NNLO in QCD, based on an observable- and process-independent cancellation of infrared singularities. As a first simple application, we present the calculation of…
The strong coupling constant is a fundamental parameter of nature. It can be extracted from experiments measuring three-jet events in electron-positron annihilation. For this extraction precise theoretical calculations for jet rates and…
I describe a class of iterative jet algorithms that are based on maximizing a fixed function of the total 4-momentum rather than clustering of pairs of jets. I describe some of the properties of the simplest examples of this class,…
This article gives the perturbative NNLO results for the most commonly used event shape variables associated to three-jet events in electron-positron annihilation: Thrust, heavy jet mass, wide jet broadening, total jet broadening, C…
In this paper, using soft-collinear effective theory we study the invariant mass distribution for dijet production in $e^+e^-$-annihilation. Near threshold, where the dijet takes most of the energy, there arise the large threshold…
We give perturbative predictions for the distribution of the $C$-Parameter event shape variable in $e^+e^-$ annihilation, including resummation of large logarithms in the two-jet (small-$C$) region, matched to next-to-leading order results.…