sPHENIX tracking discussion

[Xin Dong <xdong AT lbl.gov>]

Dear Tony and All,

Thank you very much for the great achievements. Sorry for not being able to call in today's meeting.

I am a bit concerned about the DCA resolution. The plots on slide 4 shows at 1 GeV it is only 90 microns, this is significantly worse than the previous tracking (which is about 30 microns) outcome (at 5 GeV/c, now is 25 microns vs. ~ 10 microns before). 

From the next email on the cluster parameters, they seem to be reasonable at least on the MAPS side. And it seems also the fake rate is small (my interpretation on your statement on "the tracker has already rejected clusters it does not like."). With these, I would expect the the dca resolution for the reconstructed tracks with MAPS hits should be close to what was achieved with previous tracker. 

(I showed in the Santa Fe workfest, slide 14 in

https://indico.bnl.gov/getFile.py/access?contribId=7&sessionId=0&resId=0&materialId=slides&confId=2641)

I believe Christof also showed another calculation from LiC with similar numbers, slide 16 in

https://indico.bnl.gov/conferenceDisplay.py?confId=2950)

Haiwang sent out a few plots showing the dca resolution for 5 GeV/c tracks is around 10 microns a couple of days ago. So I wonder whether this sample include also Haiwang's additional patch? It would be great to find out the best DCA performance from the current tracker which is essential for open HF program.

Thanks and Best Regards

/xin

On Fri, May 26, 2017 at 9:53 AM, Frawley, Anthony <afrawley AT fsu.edu> wrote:

Hi All,

Following up on Christof's request at the tracking meeting this morning, I extracted the cluster resolutions for clusters matched to tracks embedded in Hijing events. Here are the RMS numbers for reconstructed cluster position minus truth cluster position:

Clusters matched to Hijing embedded pion tracks:

r-phi resolution:    MAPS = 4.5 microns   INTT = 28.3 microns    TPC = 128 microns

Z resolution:          MAPS = 4.7 microns    INTT = 4745 microns   TPC = 151 microns

Clusters matched to standalone 100 pion event tracks:

r-phi resolution:    MAPS = 4.5 microns   INTT = 27.4 microns    TPC = 126 microns

Z resolution:          MAPS = 4.8 microns    INTT = 4800 microns   TPC = 159 microns

Note that it is important that these are clusters matched to tracks. That means that the tracker has already rejected clusters it does not like.

Bottom line: Not much change for clusters associated with Hijing embedded tracks.

Cheers

Tony

_______________________________________________
sPHENIX-tracking-l mailing list
sPHENIX-tracking-l AT lists.bnl.gov
https://lists.bnl.gov/mailman/listinfo/sphenix-tracking-l

--

===========================
Xin Dong
Nuclear Science Division
Lawrence Berkeley National Lab
MS70R0319, One Cyclotron Road
Berkeley, CA 94720, USA
Tel: +1-510-486-4121
Email: XDong AT lbl.gov
===========================