[Rivet] correction on ATLAS_2011_I944826 routine

[Frank Siegert]

Hi Sercan,

So this basically means that in your sample the K_S (and Lambda?) have
been set stable and don't decay. Currently, the analysis requires them
to have a given range of transverse flight distance before decaying,
so clearly this kind of analysis can't be used with Monte-Carlo
samples that set the K_S and Lambda stable. Whether this
implementation (cutting on flight distance at the particle level) is
correct for that analysis would have to be answered by somebody more
familiar with it -- Emily?

Frank

On 26 October 2012 13:13, Sercan Sen <Sercan.Sen at cern.ch> wrote:
>
> Hello Frank,
>
> I didn't run this analysis before. However, I have been running some other
> analyses and add this one to the chain now to see if there is any
> difference.
>
> I've just run over 150K events (INEL Z2*) both the previous version and the
> new version in the trunk, but there is no event survive. Most of the events
> are rejected by the flightDistance cut of Kaon/Lambda which always returns
> as 1e+07. with hepmc 2.06.08 and unit is mm..
>
> Just for my curiosity, I debug a little bit and return the pdg id of the
> particle from getPerpFlightDistance function where it truly returns this
> before the "if (decV)" scope. Events never go inside decV scope and
> therefore the value of the flighttd which is 1e+07 is dummy in the current
> code. So, all events are failed...
>
> by the way, as expected we have more events after the correction on the MBTS
> cuts and I think this will  not be only statistical effect.
>
> * ==================
>
> OLD VERSION
>
> Cross-section = 7.130367e+10 pb
> Rivet.Analysis.Handler: INFO  Finalising analyses
> Rivet.Analysis.ATLAS_2011_I944826: INFO  Events that pass the trigger:
> 112103
> Rivet.Analysis.ATLAS_2011_I944826: INFO  Kshort events: 0
> Rivet.Analysis.ATLAS_2011_I944826: INFO  Lambda events: 0
> Rivet.Analysis.Handler: INFO  Processed 150000 events
>
> NEW VERSION
>
> Cross-section = 7.130367e+10 pb
> Rivet.Analysis.Handler: INFO  Finalising analyses
> Rivet.Analysis.ATLAS_2011_I944826: INFO  Events that pass the trigger:
> 127174
> Rivet.Analysis.ATLAS_2011_I944826: INFO  Kshort events: 0
> Rivet.Analysis.ATLAS_2011_I944826: INFO  Lambda events: 0
> Rivet.Analysis.ATLAS_2011_I944826: INFO  This is the modified analysis,
> revision 3975
> Rivet.Analysis.Handler: INFO  Processed 150000 events
>
> Thanks,
> Sercan
>
>
>
>
>
> On Oct 25, 2012, at 3:36 PM, Frank Siegert wrote:
>
> Hi Sercan,
>
> Thanks again for the feedback. I have implemented the changes in changeset
> 3975:
>
>  http://rivet.hepforge.org/trac/changeset/3975
>
> I don't have any possibility to test whether this does something
> significantly different from before though. Sercan or Holger, since
> you are probably the only two on this list who have run this analysis
> before, do you have any chance to check with these changes?
>
> Cheers,
> Frank
>
> On 24 October 2012 11:31, Sercan Sen <Sercan.Sen at cern.ch> wrote:
>
>
> Hi Frank,
>
>
> what about the "nstable" requirement... does that only look at
>
> particles >100 MeV?
>
>
>
> yes, this is what I understand from the paper -- and it's reasonable.
>
>
> trigger cut is 2.09 < |\eta| < 3.84
>
> analysis cuts: |\eta| < 2.5, 100*MeV, ....
>
>
> I think the best way is to use another projection for the trigger
>
> requirement.
>
>
> Cheers,
>
> Sercan
>
>
>
>
>
>
>
> On Oct 23, 2012, at 3:47 PM, Frank Siegert wrote:
>
>
> Hi Sercan,
>
>
> Right. "nstable" part should be in |\eta| < 2.5 . So, if we extend the
>
>
> rapidity acceptance in the CFS projection, then we should apply a rapidity
>
>
> cut in the "nstable" part..
>
>
>
> Thanks for the clarification.
>
>
> By the way, I don't know if we need 100*MeV for ATLAS MBTS requirement (this
>
>
> is applied in the current code) ? Probably, we don't need it but this should
>
>
> be checked by someone from ATLAS..
>
>
>
> Then again the same follow-up question: If the 100 MeV is not
>
> necessary for the MBTS trigger requirement (pending confirmation by
>
> Emily), what about the "nstable" requirement... does that only look at
>
> particles >100 MeV?
>
>
> Cheers,
>
> Frank
>
>
>
>