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Vevacious  provides the possibility to check the one-loop effective potential of a given model and parameter point for the global minimum. In these checks the possibility of dangerous vacuum expectation values (VEVs) of charged or colored scalars can be taken into account and the life-time of meta-stable vacua can be calculated using Cosmotransitions . For details about the input for of Vevacious we refer the interested reader to Ref. .


The possible options are:

  • ComplexParameters, Value: list of parameters, Default: {}:
    By default, all parameters are assumed to be real when writing the Vevacious input files. However, the user can define those parameters which should be treated as complex.
  • IgnoreParameters, Value: list of parameters, Default: {}:
    The user can define a list of parameters which should be set to zero when writing the Vevacious input.
  • OutputFile, Value: String, Default, where MyModel here is the same name as is given in Start[“MyModel”]; above:
    The name used for the output file.
  • Scheme, Value: DR or MS, Default: DR for SUSY models, MS for non-SUSY models:
    Defines if as renormalization scheme [math]\overline{\text{DR}}'[/math] or [math]\overline{\text{MS}}[/math] should be used.

The first two options allow to treat parameters differently in the Vevacious output as defined in the SARAH model file.

Example: MSSM with stau VEVs

In general, three changes are always necessary to include stau VEVs in a model.

  1. Defining the particles which can get a VEV

      {{SHd0, {vdR, 1/Sqrt[2]}, {sigmad, I/Sqrt[2]},{phid,1/Sqrt[2]}},
       {SHu0, {vuR, 1/Sqrt[2]}, {sigmau, I/Sqrt[2]},{phiu,1/Sqrt[2]}},
       {SeL,  {vLR[3], 1/Sqrt[2]}, {vLI[3], I/Sqrt[2]}, 
                                       {sigmaL, I/Sqrt[2]},{phiL,1/Sqrt[2]}},
       {SeR,  {vER[3], 1/Sqrt[2]}, {vEI[3], I/Sqrt[2]}, 
                                       {sigmaR, I/Sqrt[2]},{phiR,1/Sqrt[2]}},
       {SHdm, {0, 0}, {sigmaM, I/Sqrt[2]},{phiM,1/Sqrt[2]}},
       {SHup, {0, 0}, {sigmaP, I/Sqrt[2]},{phiP,1/Sqrt[2]}},
       {SvL,  {0, 0}, {sigmaV, I/Sqrt[2]},{phiV,1/Sqrt[2]}}

    where it is important that the VEVs have names that are at least two characters long.

  2. Changing the rotation of the vector bosons:

    DEFINITION[EWSB][GaugeSector] =
      {{fWB[1],fWB[2],fWB[3]},{fWm,fWp,fW0},ZfW} }; 
  3. Changing the rotation of matter fields:

    {    ...
         {{phid, phiu,phiM,phiP,phiV,phiL,phiR}, {hh, ZH}},
         {{sigmad, sigmau,sigmaM,sigmaP,sigmaV,sigmaL,sigmaR}, {Ah, ZA}},
         {{fB, fW0, FHd0, FHu0, FvL, FeL, conj[FeR],fWm, FHdm, fWp, FHup}, {L0, ZN}}, 
         ...        };  

More information about Vevacious

See also