Flavour mixing in SARAH-SPheno framework

[amitchakraborty]

Dear Florian,

This is in the context of flavour mixing (in squark sector) in SPheno. I need a confirmation/validation from expert like you.

I have generated the SPheno model file from SARAH and passed it to SPheno (version 4.0.3) working directory. It is working perfectly fine. While studying a particular LR-mixing scenario, I find that, as expected, we are getting large radiative corrections to the yukawa couplings. So, significant portion of the parameter space with non-zero mixing is disallowed.

But then I find a note in SPheno homepage (https://spheno.hepforge.org/#_known_problems) saying:

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in the new approach starting version 4.0.2 the case of flavor mixing shows instabilities and should not be used for the moment being. In case that someone is interested in flavor mixing, the flag 49 of the block SPhenoInput should be set to 1 so that the old approach is used.
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I tried to make of use this flag 49 to validate our findings even with older implementations, but SPheno output says
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Problem while reading SPhenoInput, ignoring unknown entry 49 1.0000000000000000
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Will you please let me know whether the "instability issue" in SPheno has been already resolved so that I don't need to worry about the above message, otherwise to convince myself I wish to incorporate the flag 49 in the SARAH generated SPheno model files. Please help.
Thanks in advance.

Sincerely,
Amit

[FStaub]

Hi,

this warning refers only to the standard SPheno. The problem doesn't occur if you use a SARAH generated SPheno module.

Cheers,
Florian

[amitchakraborty]

Thanks for the confirmation.

Regards,
Amit