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

[Holger Schulz]

Hi all,

I am currently working on the LHCB analysis recently added to contrib 
(LHCB_2015_I1333223).

It's pretty straight forward what they do except for one cut in their 
phase space definition, namely
a cut on "Distance of Closest Approach in z" i.e. z_0 wrt the primary 
vertex. They use that
to define prompt particles by requiring this cut to be <0.2 mm. (Which 
is much better I think
than the whole pythia decay times map that was used in other analyses).

The way it's implemented right now is heavily using genEvent() stuff such as

  * finding primary vertex
  * finding particle production vertices

and using that information to calculate z_0.

Now I don't think that this horribly wrong at all but it would be nice to
have a more Rivet like way of doing this, maybe having a Particle.z0()
function? Not sure though.

What do you think?

Thanks,
Holger

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://www.hepforge.org/lists-archive/rivet/attachments/20151103/282ef8ff/attachment.html>