sPHENIX EMCal discussion

[woody <woody AT bnl.gov>]

Hi Sasha,
  My statement about the degradation of the position resolution in 
central collisions was really just qualitative. I don't think I've 
actually seen any actual estimate of this, but this looks very 
encouraging. Thanks very much for checking this.

Cheers,
Craig

On 5/4/2018 12:46 PM, Alexander Bazilevsky wrote:
> Hi Craig,
>
> After your comment I was curious to see how much the position 
> resolution would degrade in the central HI collisions. We saw Joe's 
> plots illustrating the effect on the energy resolution. I've quickly 
> looked in the simulation trees and produced the attached plot, which 
> is position resolution in the barrel EMCal in tower units (here it is 
> in phi direction) for single photons (blue) vs when they are embedded 
> in the central HI (red). The usual fits gave me
>
> 0.057 + 0.10/sqrt(E) for single photon case and
>
> 0.059 + 0.21/sqrt(E) for embedded case
>
> The sum is quadratic. And, again, it is in tower units. In terms of mm 
> units, the constant term is ~1.3mm, which looks the same for both 
> cases. The resolution for single photon is quite similar to PHENIX 
> PbSc if presented in tower units, so nothing surprising here. And the 
> effect of the UE looks not critical, particularly for dir. photon 
> measurements (at higher pT).
>
> Regards,
>
> Sasha.
>
>
> On 5/4/18 8:03 AM, Craig Woody wrote:
> >  It may degrade the position resolution slightly, but our position 
> > resolution for photons will already be degraded significantly by the 
> > underlying event in central collisions.