[Halld-pid-upgrade] Some plots on the N pho raw

[Maria Patsyuk]

Hi,

answering Mike’s question below.

The events shown on the plots were chosen as:

1. preliminary selection - reconstruction of reactions: pho -> pi+ , pi- and phi -> K+, K- using dirc_reaction plugin (no cut on missing mass!)
2. tracks with best chi2 of kinematic fit (out of all possible combos)
3. tracks of pi and K, which hit the lower DIRC half
4. for the Cherenkov photons I use a loose time cut: [10, 120] ns
5. I consider only tracks pi, L with p > 4 GeV/c.

Best regards,
Maria

> On Mar 6, 2019, at 5:20 PM, Michael Williams <mwill at mit.edu> wrote:
> 
> 
>> 4. Still strange that N pho / event does not grow with the number of tracks hit the DIRC bottom half (data and sim agree here).
> 
> What is the full list of criteria used to select these events? 
> 
> If the photon is in the peak region, and you require detecting the proton, is it actually kinematically possible to have 2 real particles with p > 4 GeV on the same side of the detector? (That’s > 8 GeV just in these 2 tracks, so curious what your photon energy selection is.) 
> 
> I.e., are you just looking at cloned tracks? 
> 
> Mike
>