Star-fst-l mailing list

[Zhenyu Ye <yezhenyu2003 AT gmail.com>]

Hi Daniel, 

I think I was confused with your statements "The study from Jason was later 
changed though - he is one of the S&C people that made the point to me that 
more r segmentation was needed. I talked with him/Gene about this last 1.5 
week. Also I know that the global track efficiency on those plots is wrong, 
also from talking with Jason." "OK i talked with Gene about the hit 
rasterization in R just 1 or 2 ago”. 

I guess I know better now what was said to you after reading your email below 
but still confused to some extent. So is it correct that Gene (and Jason?) 
pointed out to you the importance of r rasterization, and Jason pointed out 
to you the need of more r segmentations?

Thanks,
Zhenyu

> On Jun 26, 2019, at 8:46 AM, Daniel Brandenburg 
> <dbrandenburg.ufl AT gmail.com> wrote:
> 
> Hi all, 
> 
> maybe just a little clarification:
> 
> Gene, in our meeting a week ago about the forward tracking we discussed 
> difficulty with the silicon. Specifically I talked about the resolution in 
> R and you guys mentioned that rasterizing the hits was study and found to 
> be important. 
> 
> Jason, we talked about the global efficiency some time ago now. We did 
> several studies of the lambda decays with the older fast sim (with 
> different resolution etc.) and with the newer ones for Si and sTGCs. We 
> found that the lambda daughters (true global tracks, not just primary 
> tracks without the primary vertex included in fit) had a very low 
> reconstruction efficiency ( maybe 10%, I dont remember exactly) - we talked 
> about this and how the tracker does the track following etc. 
> So my comment is not so much that those plots are wrong but that it is 
> definitely not the performance we see with the current detector 
> resolutions. I hope that is clear.
> 
> Since i was not active with the forward tracking before last year I 
> understand that a lot was done before I was active. I want to make sure we 
> fully understand this issue before we get further along. 
> 
> Best,
> Daniel
> 
> 
> On Wed, Jun 26, 2019 at 9:16 AM Zhenyu Ye <yezhenyu2003 AT gmail.com> wrote:
> Hi Jason, Gene, 
> 
> I was told by Daniel Brandenburg that you made the point to him very 
> recently that more radial segmentations are absolutely needed for Forward 
> Silicon Tracker. This would contradict to the statement in page 41 of the 
> proposal 
> https://drupal.star.bnl.gov/STAR/system/files/ForwardUpgrade.v20.pdf
> 
> “In addition, we increased the radial segmentation from 8 to 16, 32, and 64 
> and found no significant improvement on the momentum resolution or tracking 
> efficiency.”
> 
> Can you please help me understand why you believe more radial segmentations 
> are needed for FST?
> 
> Jason, I was also told by Daniel that the global track efficiency for those 
> plots is wrong. Can you please tell me what is wrong with them?
> 
> Thanks,
> Zhenyu