STAR HardProbes PWG

["Ma, Rongrong" <marr AT bnl.gov>]

Hello Veronica, Dave

I would like to follow up on this topic as I still do not fully understand y-axis either. 

What do you mean by "in doing the embedding, we do get a different ZDCx"? I would see that the ZDCx distributions are different between data and embedding, but for a given event there is only one ZDCx as recorded by ZDC during data taking, right? So maybe the question is how exactly do you obtain ZDCx_embed and ZDCx_data for a given event that goes into this efficiency plot. Could you show a snippet of  your code?

Thanks. 

Best

Rongrong

On Jan 20, 2023, at 1:18 AM, Veronica Verkest via Star-hp-l <star-hp-l AT lists.bnl.gov> wrote:

1) SLide#6:
_ What is Y-axis "ZDCX-bin data"? how do you calculate efficiency value
from data? (Not clear)

_ are these efficiency values are pT- and eta- integrated one?

These efficiency values are integrated over pT and eta. This plot might be more visually intuitive if you ignore the 7th bin on the x-axis, as this is just the average of the bins to the left. There is a typical pT-dependence shape in the curves and some slight dependence on eta (the asymmetry of the UE means different populations and therefore different efficiency for different eta-ranges in the TPC). The data-ZDCx bins were clear to me (first seeing the plot) as it is directly from the detector, but I had to reconcile to myself that, in doing the embedding, we do get a different ZDCx. The significance here is that the efficiency curves do not vary significantly as a function of the embedding ZDCx. This shows us that all tracks (real and PU) can be efficiency-corrected the same way, as the embedding ZDCx does not discriminate.