[Rivet] New LHCB analysis --- definition of z_0

[David Grellscheid]

Hi Andy,

On 04/11/2015 12:25, Andy Buckley wrote:
> Isn't Beams::IP always going to be (0; 0,0,0)? We used to have a
> PrimaryVertex projection and it was totally pointless.

I'd still leave it in. ThePEG can generate IP offsets (although nobody 
uses them), and I could imagine other situations that we shouldn't lock out.

   David