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

[Michael Williams]

I would suggest looking only at the pions and requiring p > 2 GeV. 

It could be insightful to also plot the dipion mass for your current sample for the 1 and 2 track cases. Is there a nice rho peak in both? (Same question for the phi.) 

Mike


> On Mar 7, 2019, at 11:39 AM, Maria Patsyuk <mpatsyuk at mit.edu> wrote:
> 
> 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
>> 
>