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  • SPheno_and_Monte Carlo_tools

Last edited by Martin Gabelmann Dec 11, 2019
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SPheno_and_Monte Carlo_tools

SPheno and Monte-Carlo tools

Model files for MC tools

SARAHwrites all necessary files to implement a new model in different MC tools. We show how these model files together with the parameter values obtained by SPheno can be used in a straight forward form. For the output of the models files check

  • CalcHep: SARAH interface to CalcHep and CompHep
  • MadGraph: UFO output of SARAH
  • WHIZARD: SARAH interface to WHIZARD/OMEGA

Interplay SARAH–SPheno–MC-Tool

The tool chains SARAH–SPheno–MC-Tools have one very appealing feature: the implementation of a model in the spectrum generator (SPheno) as well as in a MC tool is based on just one single implementation of the model in SARAH. Thus, the user does not need to worry that the codes might use different conventions to define the model. In addition, SPhenoalso provides all widths for the particles so that this information can be used by the MC-Tool to save time.

CalcHep

CalcHep is able to read the numerical values of the masses and mixing matrices from a SLHA spectrum file based on the SLHA+ functionality. SARAH makes use of this functionality to generate model files by default in a way that they automatically expect to find the input values in spectrum files written by a SARAH-generated SPheno version. However, other choices are possible: the parameters can be given via the vars file or tree-level expressions can be calculated internally by CalcHep.

MadGraph

The spectrum file written by SPheno can be directly used as parameter card in MadGraph.

WHIZARD/O’Mega

Since the SLHA reader of WHIZARD is at the moment restricted to the MSSM and the NMSSM, SPheno versions generated by SARAH can write all information about the spectrum and parameters in an additional file in the WHIZARD specific format. This file can then be read by WHIZARD. Currently, the handling of general Lorentz structures in WHIZARD and the support of the UFO format are under development. This will provide the possibility to use WHIZARD with the calculated diphoton and digluon vertices as explained in the following.

Effective diphoton and digluon vertices

The effective diphoton and digluon vertices calculated by SPheno are directly available in the UFO model files and the CalcHep model files: SARAH includes the effective vertices for all neutral scalars to two photons and two gluons, and the numerical values for these vertices are read from the spectrum file generated with SPheno. For this purpose, a new block EFFHIGGSCOUPLINGS is included in these files, which contains the values for the effective couplings including all corrections outlined in . It is important to mention that these effective couplings correspond to the decay of the scalar; if we use CalcHep or MadGraph to compute the decay \Phi \to gg then the value matches (as closely as possible) the NNNLO value, which includes real emission processes such as \Phi \to ggg. Therefore, the corrections at NLO and beyond for \Phi \to gg are not the same as pp\to \Phi via gluon fusion ; the full NNNLO production cross-section includes all processes gg\to \Phi + \text{ jet} and is therefore described by a different k-factor to the decay. This k-factor can for instance be obtained via

k = c_{\Phi gg} \cdot \frac{\sigma_{\rm SM}(pp \to H(M_{\Phi})+ \mathrm{jet})}{\sigma_{\rm MC}(pp \to \Phi)}

where c_{\Phi gg} is the ratio squared of the effective coupling between \Phi and two gluons at LO in the considered model and the SM. These values can for instance be read off by the block HiggsBoundsInputHiggsCouplingsBosons in the SPhenospectrum file. \sigma_{\rm SM}(pp \to H(M_{\Phi})) is the cross section for a SM-like Higgs with mass M_{\Phi}. This value can be calculated for instance with Higlu or Sushi for the considered center-of-mass energy. SPheno also provides values for c_{\Phi gg} \cdot \sigma_{\rm SM}(pp \to H(M_{\Phi})) for the most common energies in the blocks HiggsLHCX (X=7,8,13,14) and HiggsFCC, see also SPheno_Higgs_production.

On the other hand, this approach is not entirely appropriate for more refined collider analyses where the user would like to actually include, for example, a hard jet in the final state (without the full loop corrections to the effective vertex this is not an infra-red safe quantity).

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Index

  • Additional terms in Lagrangian
  • Advanced usage of FlavorKit
  • Advanced usage of FlavorKit to calculate new Wilson coefficients
  • Advanced usage of FlavorKit to define new observables
  • Already defined Operators in FlavorKit
  • Already defined observables in FlavorKit
  • Auto-generated templates for particles.m and parameters.m
  • Automatic index contraction
  • Basic definitions for a non-supersymmetric model
  • Basic definitions for a supersymmetric model
  • Basic usage of FlavorKit
  • Boundary conditions in SPheno
  • CalcHep CompHep
  • Calculation of flavour and precision observables with SPheno
  • Checking the particles and parameters within Mathematica
  • Checks of implemented models
  • Conventions
  • Decay calculation with SPheno
  • Defined FlavorKit parameters
  • Definition of the properties of different eigenstates
  • Delete Particles
  • Different sets of eigenstates
  • Diphoton and digluon vertices with SPheno
  • Dirac Spinors
  • FeynArts
  • Fine-Tuning calculations with SPheno
  • Flags for SPheno Output
  • Flags in SPheno LesHouches file
  • FlavorKit
  • FlavorKit Download and Installation
  • Flavour Decomposition
  • GUT scale condition in SPheno
  • Gauge Symmetries SUSY
  • Gauge Symmetries non-SUSY
  • Gauge fixing
  • Gauge group constants
  • General information about Field Properties
  • General information about model implementations
  • Generating files with particle properties
  • Generic RGE calculation
  • Global Symmetries SUSY
  • Global Symmetries non-SUSY
  • Handling of Tadpoles with SPheno
  • Handling of non-fundamental representations
  • HiggsBounds
  • Higher dimensionsal terms in superpotential
  • Input parameters of SPheno
  • Installation
  • Installing Vevacious
  • LHCP
  • LHPC
  • LaTeX
  • Lagrangian
  • Loop Masses
  • Loop calculations
  • Loop functions
  • Low or High scale SPheno version
  • Main Commands
  • Main Model File
  • Matching to the SM in SPheno
  • MicrOmegas
  • ModelOutput
  • Model files for Monte-Carlo tools
  • Model files for other tools
  • Models with Thresholds in SPheno
  • Models with another gauge group at the SUSY scale
  • Models with several generations of Higgs doublets
  • More precise mass spectrum calculation
  • No SPheno output possible
  • Nomenclature for fields in non-supersymmetric models
  • Nomenclature for fields in supersymmetric models
  • One-Loop Self-Energies and Tadpoles
  • One-Loop Threshold Corrections in Scalar Sectors
  • Options SUSY Models
  • Options non-SUSY Models
  • Parameters.m
  • Particle Content SUSY
  • Particle Content non-SUSY
  • Particles.m
  • Phases
  • Potential
  • Presence of super-heavy particles
  • RGE Running with Mathematica
  • RGEs
  • Renormalisation procedure of SPheno
  • Rotations angles in SPheno
  • Rotations in gauge sector
  • Rotations in matter sector
  • SARAH in a Nutshell
  • SARAH wiki
  • SLHA input for Vevacious
  • SPheno
  • SPheno Higgs production
  • SPheno Output
  • SPheno and Monte-Carlo tools
  • SPheno files
  • SPheno mass calculation
  • SPheno threshold corrections
  • Setting up SPheno.m
  • Setting up Vevacious
  • Setting up the SPheno properties
  • Special fields and parameters in SARAH
  • Superpotential
  • Support of Dirac Gauginos
  • Supported Models
  • Supported gauge sectors
  • Supported global symmetries
  • Supported matter sector
  • Supported options for symmetry breaking
  • Supported particle mixing
  • Tadpole Equations
  • The renormalisation scale in SPheno
  • Tree-level calculations
  • Tree Masses
  • Two-Loop Self-Energies and Tadpoles
  • UFO
  • Usage of tadpoles equations
  • Using SPheno for two-loop masses
  • Using auxiliary parameters in SPheno
  • VEVs
  • Vertices
  • Vevacious
  • WHIZARD