Helac - A Monte Carlo Generator for Multi-Jet Processes

Abstract

The status of the multi-purpose event generator HELAC is briefly presented. The aim of this tool is the full simulation of events within the Standard Model (SM) at current and future high energy experiments, in particular the LHC. Some results related to the production of multi-jet final states at the LHC are also discussed.

HELAC-Onia: An automatic matrix element generator for heavy quarkonium physics

“…After applying the spin projection, the two external wavefunctions for open 5 We write the Fock states in the spectroscopic form of n = 2S+1 L [c] J , where S, L, J identify the spin, orbital momentum, total angular momentum states respectively, and c = 1, 8 means that the intermediate state QQ can be in color-singlet or color-octet state. 6 In HELAC-Onia, we also generalize the projectors in the case of the heavy quarks in different flavors that form a heavy quarkonium like B c . But for simplicity, we only consider the same flavor case here.…”

Simulation of photon-photon interactions in hadron collisions with Sherpa

“…Besides the well-established multi-purpose generators [1,2] and their modern versions [3,4], new codes have emerged which put special emphasis on the correct description of multi-particle production through the corresponding exact treelevel matrix elements [5,6,7,8]. In the case of QCD and QCD-associated final states, techniques are available to combine higher order real corrections with resummation described by parton shower programs.…”

“…In the case of QCD and QCD-associated final states, techniques are available to combine higher order real corrections with resummation described by parton shower programs. Such techniques are implemented for example in the generators ALPGEN [5], HELAC [6], MADEVENT [9] and SHERPA [8]. Given the decreasing accuracy of resummation with increasing hardness of radiation, it is important at current and future colliders to have at hand techniques to predict and reliably describe signals of, and backgrounds to, new physics.…”

“…AMEGIC++ proves to be competitive to other high-multiplicity generators, like e.g. ALPGEN [5], CompHEP [25], HELAC [6] and MADGRAPH [26]. In the near future, SHERPA will also include a new matrix element generator for the production of very large multiplicity final states [27].…”

MadGraph/MadEvent : a multipurpose event generator

“…At the matrix element level, these include the development of general purpose event generators, such as CompHEP/CalcHEP [1,2], SHERPA [3] and WHIZARD [4], high efficiency multiparton generators which go beyond the usual Feynman diagram techniques, such as ALP-GEN [5] and HELAC [6].…”