Related papers: HELAS and MadGraph/MadEvent with spin-2 particles
Fortran subroutines to calculate helicity amplitudes with massive spin-3/2 particles, such as massive gravitinos, which couple to the standard model and supersymmetric particles via the supercurrent, are added to the HELAS (HELicity…
Fortran subroutines to calculate helicity amplitudes with goldstinos, which appear as the longitudinal modes of massive gravitinos in high energy processes, are added to the HELAS (HELicity Amplitude Subroutines) library. They are coded in…
The program MadGraph is presented which automatically generates postscript Feynman diagrams and Fortran code to calculate arbitrary tree level helicity amplitudes by calling HELAS[1] subroutines. The program is written in Fortran and is…
HELAC is a FORTRAN based package that is able to compute efficiently helicity amplitudes for arbitrary scattering processes within the standard electroweak theory. The algorithm exploits the virtues of the Dyson-Schwinger equations as…
HELAC-PHEGAS is a FORTRAN based package that is able to compute automatically and efficiently tree-order helicity amplitudes and cross sections for arbitrary scattering processes within the standard electroweak theory and QCD. The algorithm…
Spin-2 particles and in particular gravitons are predicted in many new physics scenarios at the TeV scale. Depending on the details of models such new states might show up as a continuum, massless particles, or TeV scale resonances.…
We develop the helicity formalism for spin-2 particles and apply it to the case of gravity in flat extra dimensions. We then implement the large extra dimensions scenario of Arkani-Hamed, Dimopoulos and Dvali in the program AMEGIC++,…
We develop a method to calculate helicity amplitudes of an arbitrary tree-level process in Feynman-Diagram (FD) gauge for an arbitrary gauge model with MadGraph5_aMC@NLO. We start from the 't Hooft-Feynman gauge Lagrangian in FeynRules and…
We develop the formal tools needed to construct helicity amplitudes for massive gravitino in N=1 SUGRA. We start by considering the helicity states for massive spin-3/2 particles, which involves the solutions of Rarita-Schwinger equation.…
The spinor helicity formalism (SHF) has been efficiently applied to compute perturbative amplitudes in plenty of processes and reactions in gauge theories (including gravity), mostly in the massless case. Some work has been done in order to…
Both 3- and 4-point scattering amplitudes for spin-1 massless particles (gluons) and spin-2 massless particles (gravitons) are reviewed through self-contained step-by-step derivation. Gluon and graviton interactions are computed from…
We present a fully automated framework to compute production spin-density matrices for generic collider processes at tree level within \textsc{MadGraph5\_aMC@NLO}. The method assembles helicity amplitudes into event-by-event production…
We present the latest developments of the MadGraph/MadEvent Monte Carlo event generator and several applications to hadron collider physics. In the current version events at the parton, hadron and detector level can be generated directly…
We present an application that automatically writes the Helas library corresponding to the Feynman rules of any Lagrangian, renormalizable or not, in quantum field theory. The code, written in Python, takes the Universal FeynRules Output as…
We present the implementation of the dipole subtraction formalism for the real radiation contributions to any next-to-leading order QCD process in the MadGraph/MadEvent framework. Both massless and massive dipoles are considered. Starting…
We present a prescription to calculate manifestly gauge invariant tree-level helicity amplitudes for arbitrary scattering processes with off-shell initial-state gluons within the kinematics of high-energy scattering. We show that it is…
The novel massive spinor-helicity formalism of Arkani-Hamed, Huang and Huang provides an elegant way to calculate scattering amplitudes in quantum chromodynamics for arbitrary quark spin projections. In this note we compute two families of…
Support for interactions of spin-3/2 particles is implemented in the FeynRules and ALOHA packages and tested with the MadGraph 5 and CalcHEP event generators in the context of three phenomenological applications. In the first, we implement…
Using the classical recursion relations we compute scattering amplitudes in a spontaneously broken Gauge-Higgs theory into final states involving high multiplicities of massive vector bosons and Higgs bosons. These amplitudes are computed…
Manifestly Lorentz covariant Feynman rules are given in terms of a "scalar" field for each helicity, dramatically simplifying the calculation of amplitudes with massless particles. The spinor helicity formalism is properly identified as a…