Two changes have taken place in SARAH-3.0.beta30 which might demand some changes in the input files:
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1) Rotations in gauge sector:
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The syntax for the definition of rotations in the gauge sector has been changed. It has now the general
shape which is supposed to be easier to read:
{{Original particles},{Rotated particles}, Rotation Matrix}
For example, the Photon-Z mixing can be written as
{{VB, VWB[3]},{VP,VZ},ZZ}
The parametrization of ZZ by the Weinberg angle can be done in the parameters.m file using the "Dependences"
command. The new syntax simplified the definition of models with additional gauge bosons and more complicated
mixings among the gauge bosons. In this context, also the mass matrices for the gauge bosons are calculated and
by the command " MassMatrix[Field]".
Concerning the SPheno output: the mixing matrices and mass eigensates in the gauge sector are now numerically
calculated by the diagonalization of the mass matrix. The corresponding mixing angles can be extracted from
that the values of the mixing matrix by the command "DependenceSPheno", e.g.
DependenceSPheno -> ArcCos[ZZ[1,1]].
The old syntax is still supported (Head: GaugeSectorOld), but no longer recommended.
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2) GUT scale condition in SPheno
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It is now possible to define a condition for the GUT scale in the produced SPheno code:
ConditionGUTscale = l.h.s == r.h.s;
For example, the usual condition just reads
ConditionGUTscale = g1 == g2;
However, it is also possible to use more complicated equations. For instance, for the case of two abelian gauge
groups and kinetic mixing, the condition might read
ConditionGUTscale = (g1*g1p-g1g1p*g1pg1)/Sqrt[g1p^2-g1pg1^2] == g2;
If no condition is defined in SPheno.m, the unification of the first two gauge couplings in the array "Gauge" is
taken.
Date: 12. September 2011