RGE running of Dirac gauginos

[Amin]

Hi Florian,

I am using the MSSM Stueckelberg model in SARAH and turning on the gauge kinetic mixing. All steps proceed normally and SPheno compiles successfully. Now for the Dirac gaugino MDBpS above a certain value, the RGE running stops with the message:

Calculating mass spectrum
1 .-iteration
RGE running not possible. Errorcode: -4
Note: The following floating-point exceptions are signalling: IEEE_DIVIDE_BY_ZERO IEEE_UNDERFLOW_FLAG IEEE_DENORMAL
STOP Subroutine TerminateProgram

I believe the error is coming from the RGE of MDBpS. Also I notice that the mixed gauge couplings g_YB and g_BY turn out to be zero at the SUSY scale. I have followed the same steps as in the B-L-SSM model to set up SPheno.m. I'm not sure why the RGE running stops.
I am attaching the SARAH files, StMSSM_Mix.zip, the SPheno source code, SPheno_StMSSM_Mix.zip and the LesHouches input file (with Messages.out where the error is shown) in files.zip.
Could you please have a look? I appreciate it.

Thanks a lot,
Amin

[FStaub]

Hi,

I don't think that this model has gauge coupling unification, or? Thus, I guess that SPheno won't find g1==g2 (below the M_Planck) and stops running.

Cheers,
Florian

[Amin]

Hi,

Thanks Florian. Is there a way to fix it? Or may be just resort to a low scale model?

Best,
Amin

[FStaub]

Hi,

what means fixing?
1) Add fields to get a gauge coupling unification
2) Put a "GUT" scale by hand (ie. tell SPheno where it should stop to run) That can be done via flag 31). But it's not clear what this scale has for a physical meaning.

Cheers,
Florian

[Amin]

Thank you Florian. I am going to think about this. Thanks for your input.

Best wishes,
Amin

[Amin]

Hi Florian,

Gauge coupling unification should be guaranteed in this model. The reason is that the couplings g_YB and g_BY are proportional to the gauge kinetic mixing coefficient which I chose to be small. So, the running of the gauge couplings should be identical to the MSSM case. That's why I do not understand why this is happening. Now since this is now an issue in SPheno, I will open up a ticket there.

Thank you,
Amin