Squared Missing?

[AWlotzka]

Hello,

in the LowRatio Approximations (both boson and fermion) for the thermal corrections in the file VevaciousRunner.cpp, is there a squared missing in the log? So shouldn't the log have (m/T)^2 as argument instead of (m/T)?

Cheers,
Alexander

[benoleary]

Hi, Alexander,

log(x^2) = 2 * log(x). You should find that the factor of 2 has been correctly accounted for in the prefactor (along with the checks against negative argument).

Regards,
Ben

[AWlotzka]

Sure, but if I'm correct your log-term in the expansion reads

-1/32 (m/T)^4 (log(m/T) - (3/2 +2 log(4Pi) - 2gamma_Euler))

This is in contradiction with the expansion in (for instance) hep-ph/9901312 and hep-ph/9609240.
Or am I missing anything?

Cheers,
Alexander

[benoleary]

Oh, looks like you are right. I'd have to check other references though - I don't remember if Quiros was our source for those equations. If so, I'll put in the missing 0.5.

The effects should be numerically very small, as those equations are only used when m/T is very small, and (very small)^4 * (wrong log) is still going to be very small. It will get corrected though.

[benoleary]

Version 1.2.02 now has the correction in the coefficient.