840 research outputs found
UFO 2.0: the âUniversal Feynman Outputâ format
We present an update of the Universal FeynRules Output model format, commonly known as the UFO format, that is used by several automated matrix-element generators and high-energy physics software. We detail different features that have been proposed as extensions of the initial format during the last ten years, and collect them in the current second version of the model format that we coin the Universal Feynman Output format. Following the initial philosophy of the UFO, they consist of flexible and modular additions to address particle decays, custom propagators, form factors, the renormalisation group running of parameters and masses, and higher-order quantum corrections
New developments in FeynRules
The program FeynRules is a Mathematica package developed to facilitate the
implementation of new physics theories into high-energy physics tools. Starting
from a minimal set of information such as the model gauge symmetries, its
particle content, parameters and Lagrangian, FeynRules provides all necessary
routines to extract automatically from the Lagrangian (that can also be
computed semi-automatically for supersymmetric theories) the associated Feynman
rules. These can be further exported to several Monte Carlo event generators
through dedicated interfaces, as well as translated into a Python library,
under the so-called UFO model format, agnostic of the model complexity,
especially in terms of Lorentz and/or color structures appearing in the
vertices or of number of external legs. In this work, we briefly report on the
most recent new features that have been added to FeynRules, including full
support for spin-3/2 fermions, a new module allowing for the automated
diagonalization of the particle spectrum and a new set of routines dedicated to
decay width calculations.Comment: 6 pages. Contribution to the 15th International Workshop on advanced
computing and analysis techniques (ACAT 2013), 16-21 May, Beijing, Chin
Direct Detection of Dark Matter with MadDM v.2.0
We present MadDM v.2.0, a numerical tool for dark matter physics in a generic
model. This version is the next step towards the development of a fully
automated framework for dark matter searches at the interface of collider
physics, astro-physics and cosmology. It extends the capabilities of v.1.0 to
perform calculations relevant to the direct detection of dark matter. These
include calculations of spin-independent/spin-dependent nucleon scattering
cross sections and nuclear recoil rates (as a function of both energy and
angle), as well as a simplified functionality to compare the model points with
existing constraints. The functionality of MadDM v.2.0 incorporates a large
selection of dark matter detector materials and sizes, and simulates detector
effects on the nuclear recoil signals. We validate the code in a wide range of
dark matter models by comparing results from MadDM v.2.0 to the existing tools
and literature.Comment: 38 pages, 8 figures, 5 tables; v2. Matches the version accepted for
publication in Physics of the Dark Universe. We have improved table IV by
validating the other sps points of the MSS
Computing decay rates for new physics theories with FeynRules and MadGraph5/aMC@NLO
We present new features of the FeynRules and MadGraph5/aMC@NLO programs for
the automatic computation of decay widths that consistently include channels of
arbitrary final-state multiplicity. The implementations are generic enough so
that they can be used in the framework of any quantum field theory, possibly
including higher-dimensional operators. We extend at the same time the
conventions of the Universal FeynRules Output (or UFO) format to include decay
tables and information on the total widths. We finally provide a set of
representative examples of the usage of the new functions of the different
codes in the framework of the Standard Model, the Higgs Effective Field Theory,
the Strongly Interacting Light Higgs model and the Minimal Supersymmetric
Standard Model and compare the results to available literature and programs for
validation purposes.Comment: 32 pages, 2 figures. Published versio
Automated mass spectrum generation for new physics
We describe an extension of the FeynRules package dedicated to the automatic
generation of the mass spectrum associated with any Lagrangian-based quantum
field theory. After introducing a simplified way to implement particle mixings,
we present a new class of FeynRules functions allowing both for the analytical
computation of all the model mass matrices and for the generation of a C++
package, dubbed ASperGe. This program can then be further employed for a
numerical evaluation of the rotation matrices necessary to diagonalize the
field basis. We illustrate these features in the context of the
Two-Higgs-Doublet Model, the Minimal Left-Right Symmetric Standard Model and
the Minimal Supersymmetric Standard Model.Comment: 11 pages, 1 table; version accepted by EPJ
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