sPHENIX tracking discussion

["Frawley, Anthony" <afrawley AT fsu.edu>]

Hi All,

Here are the minutes from today's tracking meeting.

Tony

June 24, 2106 tracking meeting:
-----------------------------------------

Mike McCumber - Tracking status
--------------------------------------------
Mike gave a nice review of where the tracking stands, and what the goals and needed capabilities are.

There was a discussion about which of the items on slide 1 are priorities for before the tracking review (expected to be September 7-9).

Bullets 5 and 4 are the top priorities for the tracking review:
Bullet 5 (pileup simulations) is the top priority before the review.
Bullet 4 (add vertex point as point in track fit) is possible - need covariance, but Mike is having trouble with that.
For bullets 4 and 5, we should ask for regular reports on the GenFit and RAVE efforts.

Bullet 2 will be imortant if pileup confuses the initial vertex guess - if it does, we need it before the review, otherwise we don't need it.
Bullet 1 is not needed for the tracking review, but it would be good to be able to check that it does not matter much.
Bullet 3 could be done, but is not essential.

Gaku asked if there is a prototype in the code now for ladder geometry. Yes, there is an early version of the proposed strip detector in coresoftware.

Krista Smith and Tony Frawley - effect of different thicknesses of the intermediate tracker
------------------------------------------------------------------------------------------------------------------------
Krista ran some simulations to get the pT resolution for 3 maps layers + TPC tracking with:
a) no intermediate tracker
b) Intermediate tracker at 18 cm with 2% radiation length thickness
c) Intermediate tracker at 18 cm with 4% radiation length thickness

The constant term (multiple scattering term) in the ΔpT/pT resolution was respectively: 0.64%, 0.93%, 1.1%. This would cause a very significant worsening of the Upsilon mass resolution, even at 2%.

We will try to get some Upsilon mass resolution estimates by Tuesday.

There was discussion about how thick the proposed silicon strip layers for the intermediate tracker would be. Gaku said 0.8% per layer, so 2 layers = 1.6%.

A maps layer would work, the middle stave would be 80 cm long in Z - covers all of the nominal tracking acceptance - note that events outside the 27 cm inner barrel are not trackable anyway. Probably pretty expensive, but we should cost it.

We will meet again next week for a detailed discussion of the proposal for a silicon strip intermediate tracker and a drift chamber.