Softsusy

[physlad]

Any experts in using SOFTSUSY (the tool) here?

[chrispb]

I've used it before, but I'm no expert.

[physlad]

Thanks for responding, chrispb! So are you familiar with the leshouches input/output? If yes, I was trying to let softsusy make some approximate calculations for me, but it refuses to do that because it's too accurate! (I get all sorts of problems, tachyons, non-convergence, etc.). Basically, I'm trying to set some of the input parameters (at GUT scale) to zero, then let softsusy run down to M_z. and I'm only interested in the value of mh2^2 at M_z. But it seems I can't set those to zero or play around. Did I confuse you? :p

[chrispb]

Well, even if you set parameters to 0, they can still run under the RG. Furthermore, the higgs mass is rather sensitive to a bunch of the couplings in the MSSM; I believe the program operates with the two-loop beta functions. So, just restricting yourself to a particular few parameters and asking how those affect the higgs mass is going to give you an incomplete story. If you're looking to actually physically remove particles and their couplings from the theory, that would require modifying the beta function, which I believe is hard-coded into softsusy. It might be modifiable; I don't know.