scale setting in calculation of low energy observables

[WojciechKotlarski]

Hi Florian,

I have a question about how the parameters are run to the scale at which the low energy observables are computed. In CalculateLowEnergyConstraints subroutine you first run to the top scale and calculate quark-related observables. Then you run to the mZ to do the same for the lepton ones. The thing that confuses me is that every time you invoke the RunSM_and_SUSY_RGEs subroutine it sets globally the scale, which can be obtained back by the function getRenormalizationScale(). This scale is used internally by RunSM_and_SUSY_RGEs to determine, at which scale the input parameters are passed to that routine (you only pass the targe scale). The moment you invoke RunSM_and_SUSY_RGEs to run to the mZ scale it take the SUSY scale parameters but inteprets them as given at the scale of 160 GeV. If I put now instead of mZ a 1 TeV (and I'm using SPA convention [flag 2 =1]) I'm not getting back the 1 TeV parameters. Am I missing something or should there be a reset of scale before the second RunSM_and_SUSY_RGEs invocation?

cheers,
Wojciech

[FStaub]

Hi,

wow, you dug really deep into the code. It seems that you are correct, there is a re-setting of the scale missing before the call of the second running to M_Z. It should read

Code: Select all

!-------------------------------------
! running to M_Z 
!-------------------------------------

scalein = SetRenormalizationScale(scale_save**2) 

Call RunSM_and_SUSY_RGEs(mz,g1input,g2input,g3input,Ydinput,Yeinput,Yuinput,          & 
...

It seems that this has dropped out already some time ago and was never recognized (most likely because it 'only' affects the LFV observables). So, thanks a lot for pointing it out!

Cheers,
Florian