sPHENIX MAPS tracker discussion

[Ming Liu <ming AT bnl.gov>]

Hi Xin and Sanghoon,

Thanks for the information, sounds reasonable. I wonder 3-layer mvtx could perform better in rejecting the fake matchings over 2-layer HFT?

Cheers 

Ming

Sent from my iPhone

On Aug 23, 2018, at 10:25 PM, Xin Dong <xdong AT lbl.gov> wrote:

Hi Sanghoon, Ming,

I think in principle both the fake matches and secondaries can contribute to the long tail. Their contributions will both decrease when moving to high pT. In the current sPHENIX tracking configuration, the fake matches seem not to be a major contribution while I can imagine the secondaries may be dominant. In the STAR HFT case at high luminosity AuAu, the fake matches at low pT dominate the tail.  

Sanghoon, from simulation, you should be able to identify each component: MC primary with true match, MC primary with fake match, MC secondaries. Thanks and Regards

/xin

On Thu, Aug 23, 2018 at 9:03 PM, Sanghoon Lim <shlim AT rcf.rhic.bnl.gov> wrote:

Hi Ming,

I also have a brief email exchange with Jin about the long tails, and it may be just due to decayed particles in pythia events. When I looked back one of Tony's slides showing DCA distribution with prompt pions (pg. 6 in https://indico.bnl.gov/event/3387/contributions/9784/attachments/8788/10770/Directors_Review_Aug_2017_tracking_software.pdf), there's no such long tail. I'm gong to check DCA distributions for prompt and decayed particles separately.

Best,

Sanghoon

On Aug 23, 2018, at 9:39 PM, mxliu <ming AT bnl.gov> wrote:

Hi Sanghoon,

Very encouraging results. Do you know these long DCA tails are caused by multiple scatterings (beam pipe, MVTX staves, INTT) or somehow intrinsic to some random background in tracking? I notice the tails are much less relative to the central peak for higher pT tracks. 

Cheers,

Ming

 

-- 

Ming Xiong Liu

P-25, MS H846                     TEL:505-667-7125 

Physics Division                             631-344-7821(BNL)

LANL                                               630-840-5708(FNAL)

Los Alamos, NM 87545      FAX:        505-665-7020

 

 

From: Sanghoon Lim <shlim AT rcf.rhic.bnl.gov>
Date: Thursday, August 23, 2018 at 8:22 PM
To: Xin Dong <xdong AT lbl.gov>
Cc: "Ming Liu (BNL)" <ming AT bnl.gov>, Molly Taylor <mitay AT umich.edu>, Carlos Perez <carlos.perezlara AT stonybrook.edu>, Mickey Chiu <chiu AT bnl.gov>, "sphenix-intt-l AT lists.bnl.gov" <sphenix-intt-l AT lists.bnl.gov>, "Chiu, Mickey" <chiu AT rcf.rhic.bnl.gov>, sPHENIX-MVTX <sphenix-maps-l AT lists.bnl.gov>, "Todoroki, Takahito" <todoroki AT rcf.rhic.bnl.gov>
Subject: Re: [Sphenix-maps-l] Next Meeting of the Inner Tracker Task Force

 

Hi Xin,

 

Sorry for the inconvenience. I included the plots in the slides on the indico page.

 

https://indico.bnl.gov/event/4885/contributions/23040/attachments/19709/26007/sPHENIX_IDTF_shlim_20180823.pptx

 

DCA is calculated with reconstructed vertex from single vertex finding with RAVE. When I check the current configuration, all tracks are used. However, tracks without MVTX hit will be de-weighted for vertex reconstruction with the adaptive filter method. This is something I need to confirm by checking vertex resolution for the high pileup case. In case of vertex resolution for p+p w/o pileup. I put a plot from my previous presentation to the updated slide above.

 

Best,

Sanghoon 

On Aug 23, 2018, at 7:47 PM, Xin Dong <xdong AT lbl.gov> wrote:

 

Hi Sanghoon,

 

Could you please post the two figures in a non-phenix directory? I seems to have permission issue with them.

 

What vertexing algorithm in the reconstruction for recalculating the DCA? Do you have the event vertex resolution vs. event multiplicity?

 

Thanks and Regards

 

/xin

 

On Thu, Aug 23, 2018 at 3:28 PM, Sanghoon Lim <shlim AT rcf.rhic.bnl.gov> wrote:

Hi Ming,

 

Requiring at least 2 associated MVTX hits already provide a huge rejection of fake tracks (tracks from pileup events). Therefore the DCA shapes are looks quite similar, as you can see in the full DCA distribution of low pT tracks (black-w/o pileup, red-w/ pileup). One thing to point is that there's still a long tail in simulation w/o pileup.

 

https://www.phenix.bnl.gov/WWW/p/draft/shlim/plots/20180823/sPHENIX_sim_pileup_pp_dca_xy_2bins.gif

https://www.phenix.bnl.gov/WWW/p/draft/shlim/plots/20180823/sPHENIX_sim_pileup_pp_dca_z_2bins.gif

 

Things may change with using realistic seed vertex instead of using true vertex, and this study will be followed when the module is ready.

 

Best,

Sanghoon  

 

On Aug 23, 2018, at 3:23 PM, mxliu <ming AT bnl.gov> wrote:

 

Hi Sanghoon,

 

Very nice work!  Is it possible to evaluate fake track rate for large DCA ghost tracks? 

 

Cheers,

Ming 

-- 

Ming Xiong Liu

P-25, MS H846                     TEL:505-667-7125 

Physics Division                             631-344-7821(BNL)

LANL                                               630-840-5708(FNAL)

Los Alamos, NM 87545      FAX:        505-665-7020

 

 

From: sPHENIX-MAPS-l <sphenix-maps-l-bounces AT lists.bnl.gov> on behalf of Sanghoon Lim <shlim AT rcf.rhic.bnl.gov>
Date: Thursday, August 23, 2018 at 2:18 PM
To: Christof Roland <christof.roland AT cern.ch>
Cc: Molly Taylor <mitay AT umich.edu>, Carlos Perez <carlos.perezlara AT stonybrook.edu>, <sanghoon.lim AT colorado.edu>, Mickey Chiu <chiu AT bnl.gov>, "sphenix-intt-l AT lists.bnl.gov" <sphenix-intt-l AT lists.bnl.gov>, "Chiu, Mickey" <chiu AT rcf.rhic.bnl.gov>, sPHENIX-MVTX <sphenix-maps-l AT lists.bnl.gov>, "Todoroki, Takahito" <todoroki AT rcf.rhic.bnl.gov>
Subject: Re: [Sphenix-maps-l] Next Meeting of the Inner Tracker Task Force

 

Hi all,

 

I produced a new set of files based on comments from the task force meeting, and you can check with the link below (added in the indico).

 

https://indico.bnl.gov/event/4885/contributions/23040/attachments/19709/26006/sPHENIX_IDTF_shlim_20180823.pptx

 

I can probably have a quick look on the performance of 2 layers of INTT with the hit files I have right now for the next week.

 

Best,

Sanghoon

 

On Aug 21, 2018, at 8:49 AM, Christof Roland <christof.roland AT cern.ch> wrote:

 

Hi Everybody, 

we will have the next meeting of the inner tracker task force, tomorrow, Wednesday, at 9am EST.
The indico link can be found here:
https://indico.bnl.gov/event/4885/

The google doc can be found here:
https://docs.google.com/document/d/17PJdu94Ydg25V-cTHIYfSbkfojH4ZUEfsfoZPm0RDb0/edit

Please update the doc by Wednesday to reflect our current status. 

Cheers

  Christof 

 

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===========================
Xin Dong
Staff Scientist, 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
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===========================
Xin Dong
Staff Scientist, 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
===========================