[Rivet] Fwd: FourMomentum mass

[Andy Buckley]

On 11/11/10 00:45, Hendrik Hoeth wrote:
> Thus spake Hendrik Hoeth (hendrik.hoeth at cern.ch):
> 
>> Guess we should catch that. In fact I thought we had already fixed
>> this several months ago.
> 
> Looking at the code, we didn't. We inserted an assert(), but left it to
> the caller to check if he gets a reasonable result.
> 
> Can someone remind me why we decided against doing at least something
> like
> 
> if (Rivet::isZero(mass2())
>   return 0.0;
> else
>   return sqrt(mass2());
> 
> This should catch the photons but will still blow up in case of a real
> problem.

I've done this now on the SVN head. I can't remember why we didn't do it
before -- possibly our main failure mode was just different -- but I can
see no reason not to. Thanks for the report!

Andy

-- 
Dr Andy Buckley
SUPA Advanced Research Fellow
Particle Physics Experiment Group, University of Edinburgh