sPHENIX is a new detector at RHIC.

[Martin Purschke <purschke AT bnl.gov>]

Here are the minutes of the 5th sPHENIX Fortnightly General Meeting:

Indico coordinates at
https://indico.bnl.gov/conferenceDisplay.py?confId=2076

*** Gunther started with an overview of events:
https://indico.bnl.gov/getFile.py/access?contribId=0&resId=0&materialId=slides&confId=2076


5 additional EC members nominated by SP team and approved by IB
        Jamie Nagle (Boulder)
        Joern Putschke (Wayne State)
        Christine Aidala (Michigan)
        Itaru Nakagawa (RIKEN)
        Huan Huang (UCLA)
Congrats to the 5 new members.

CD0 discussion is ongoing between the DOE,  ALD and spokespeople. SPs
stress the importance of moving forward soon.

The "name the collaboration" contest: If you have ideas, let the
spokespeople know. It's not really a majority vote to avoid a "Boaty
McBoatface" flap - reference here: http://www.bbc.com/news/uk-36225652

Please subscribe to the Topical Groups you are interested in - mailing
lists are the main venue to discuss and schedule.

2nd Collaboration Meeting will be held 5/18-5/20, preceded by
workshop(s) - book your accommodations soon if you haven't done so.
The IB meeting is on 5/19, time TBD. Collaboration dinner the same
evening, register your interest via a doodle poll-
http://doodle.com/poll/iexcsvqx4b92pzbb

5/31 is the deadline for the response to the ALD charge. TG's charged
with evaluating de-scoping options (later status update presentations).
Define "best worst-case" scenarios to be focused on.

ALD review of tracking options pushed back from initially envisioned
June time frame to late July to make this exercise more meaningful. Tony
commented that the results get better with time, but Ed cautioned that
with too late a date this will bunch up against other reviews, such as
the S&T review 8/23-25. In general, there will be a steady parade of
reviews all the time, and we will have to find ways to make these
efforts manageable.

Upcoming talks - we have a number of talks and speakers, but you should
name yourself or your students/post-docs/friends for consideration for
upcoming talks. There is an immediate open slot for the ICHEP early
August. Hard Probes and the QM will also come up soon.

Jamie asked if there is a general web page available to disseminate
material [equivalent to the PHENIX p/draft area]. Dave: we don't really
have a webmaster, so not quite yet. Perhaps the Wiki could take that
role, except there are open authentication issues - best option will be
evaluated.


*** Ed spoke next:
https://indico.bnl.gov/getFile.py/access?contribId=1&resId=0&materialId=slides&confId=2076

FNA test beam completed, objectives were met, very preliminary results
have been shown. Analysis is ongoing and will be refined. Early results
confirm the validity or our simulations w.r.t energy resolution etc
within 1-2% points. Refinements to come.

Inner+Outer HCal technical drawings have been generated and quotes have
been solicited from commercial shops, as well as University shops. The
Outer Hcal's steel plates are 6m long, so this looks like a job for
commercial shops, while the Inner HCal steel should be well within the
capabilities of University shops. Don and Jim are currently visiting
prospective candidate shops to talk it over.

CAD has designed and is assembling a temporary flux return for the
high-field test of the magnet. A safety review has been scheduled for
next Monday.

Ed stressed that the detector has to be installed in 1008 in April of
2021 in order to be ready in 2022. It is an aggressive schedule. I
(Martin) asked if the Run 18 now on the books will impact the schedule
since the IR will be inaccessible - no, it "only" affects the budget.

Ed pointed out that there is a sPHENIX google calendar (to be found at
https://calendar.google.com/calendar/embed?src=rjmgqjsdcihldomnvrcc5ccue8 AT group.calendar.google.com&ctz=America/New_York
) if you are looking for an open slot to have a meeting, or, if you are
into that kind of thing, want to plan your vacations around important
events.

The aforementioned tracker review will be 2.5 days in July. Jon Kotcher
will be the chair. We will have rehearsals two weeks before and re-runs
one week ahead as needed. Please communicate your blackout dates to Ed.
Please read Slide 13 for the topics covered.


*** next was Jin on "Status of simulations and reconstruction"
https://indico.bnl.gov/getFile.py/access?contribId=2&resId=0&materialId=slides&confId=2076

Jin started with recent highlights - implemented Kalman filter, improved
"RAVE" vertex finding, results on track purity + fast calorimeter
simulations for inclusive tracks (Ron and Kurt) and tracks in Jets
(Dennis) . Also DCA counting b-jet tagging (Dennis).

Software packages have been developed for the test beam setup, with
complete environments available to run simulations, reconstruction, and
analysis. A paper writing group has been set up to produce a paper about
the test beam results.

In the context of responding to the ALD charge, various simulation
setups are being put together: Calorimeter in general, the TPC, and
inner HCal (flat plates implemented). See the links in the presentation
for more details. Kurt leads the effort to implement a fast simulation
production for the Emcal for fast track reduction, Jin studies the
effects of the 2x2 Emcal tower "ganging" that's on the table for cost
savings.

Please communicate your simulation needs to Jin so we can avoid a
duplication of efforts.

Need to build an analysis machinery so the TG's can produce requested
plots with a fast turnaround.

At the end Jin showed a quick overview with links "how to get started
with sPHENIX software". Principal meetings are the Tuesday simulation
meeting. There a numerous links in his slides to point you in the right
direction.


**** next was Rosi, "Jet structure TG status, plans and needs"
https://indico.bnl.gov/getFile.py/access?contribId=4&resId=0&materialId=slides&confId=2076

Tracking and calorimetry most important for Jet structure - Hcal + Emcal
influence the jet reconstruction.
De-scoping options are a big task to quantify - going through the options:
Reduce \eta coverage to +- 0.6
Tower ganging
Trigger (not a big effect on Jets [other than statistics I guess]

Rosi showed a detailed simulation plan going through the various
scenarios, the details found well-explained in the slides.
\eta reduction can be studied largely at the generator level.
Can the HCal alone provide enough information to get jets outside the
Emcal coverage? Unclear.
Gunther suggested that the CMS particle flow analysis algorithm might
allow to recoup some jets at high/low \etas. Jamie cautioned that a
study has been done showing no significant improvement.
Dave: Will the effect on jets outside the emcal coverage be studied?
With the coverage dropping off, how is the acceptance affected? Gunther:
The CMS experience is that partially captured jets are extremely
challenging. Jamie: Are we taking the de-scoping option in \eta off the
table? Without detailed simulations we will not be able to show the
impact in a convincing way. Gunther: we should concentrate on the loss
of statistics aspect for now to make progress.
Brian pointed out that the generated pT range (50-55 GeV/c) does not
accurately cover the de-scoped \eta range - you need to go to lower pTs
to get a full picture. We concluded that we delegate this discussion to
the Topical group.

*** Jin - "HF Jet TG status, plans and needs"
https://indico.bnl.gov/getFile.py/access?contribId=3&resId=0&materialId=slides&confId=2076

A lot of TG-relevant discussions are taking place at the
simulation/software meetings (Tuesdays).
The inaugural TG meeting was April 22, good attendance.
Workfest ahead of the coll. meeting May 16/17 (2-160 at BNL).
Jin outlined the longer-term tasks - implementation in G4, Kalman
filter, multiple vertices, and different b-tagging methods.
Response to the ALD charge:
generate plots "purity vs efficiency" for the b-tagging methods in light
of the various de-scoping scenarios, generate an "impact statement".

*** Tony: Upsilon spectroscopy status, plans and needs
https://indico.bnl.gov/getFile.py/access?contribId=5&resId=0&materialId=slides&confId=2076

Performance evaluation of the various tracking options on the table with
focus on Upsilon measurement - mass resolution, statistical precision
rough outline: match truth tracks with fast-sim'ed emcal clusters
eId cuts based on emcal cluster and/or pi signature from tracking
eId cuts based on emcal clusters or fake tracks
Derive performance from findings. People working on this identified -
good mix of tracking and emcal experts.
The last slide lists the outline of the simulations in some more detail.


**** Dave: Towards best-worst-case configurations...
https://indico.bnl.gov/getFile.py/access?contribId=6&resId=0&materialId=slides&confId=2076

Projected costs for a "full" sPHENIX is $81M - expect $75M. Only $23M
are "Material and Supplies", i.e. things you need to write a purchase
order for. That means reducing that by $4M (makes 6 after contingency,
overhead, etc). $23M contain "untouchable" items, cryo, prototypes, etc
Some guidelines for de-scoping (full list in the slides) - retain
physics capabilities as much as possible, re-use existing gear, prefer
reversible de-scoping etc etc.
None of the tracking options is expected to fit into the budget realities.
a) TPC - phone meeting scheduled with experts (TomH, Harald
Appleshaeuser, ..) to answer open questions - how much "anchor"
information does the TPC need from outside tracing to correct for space
charge effects? Can the electrinics be de-scoped in a reversible way?
b) doubtful that 2 VTX layers + TPC can provide DCA
c) AaLICE inner barrel - 3 layers MAPS. Est. $4M, hard to fit into the
monetary constraints.
d) one MAPS layer? Enough?
VTX pixels not without problems - timing jumps, etc. Dose related?

Make the OHCal "thinner"
envisioned savings proportional to savings in milled steel area ~$2M
Ed cautioned that the OHCal is a fully engineered part of the overall
structural design, so changes would likely trigger going back to the
drawing board for that. Also, no possible savings in z coverage since
the OHcal doubles as flux return. That also limits how much in radius
you can "shave off".

Inner HCAL -
constitutes a modest 14% of the $4M target, so even scrapping it
completely would not yield enough. Should still be studied if, worst
case, we can even do without it.

Emcal - 2x2ganging of channels would save about $2.2M with plausible
accounting. This can be bought back easily, more or less.


Emcal - only build out to \eta = +- 0.6, as discussed before;
impact on jet containment, larger systematics, less statistics.

DAQ&Trigger - scrap envisioned "BBC" trigger detector, investigate
using/copying STAR's trigger detector; reduce DCM count by PHENIX-style
multiplexing, reduce computing purchases through hand-me-downs, ...

Dave gave some examples for $4M and $6M savings, see slides 14 & 15.

Brian asked how confident we are that those savings are real. Dave said
that unavoidable charges have not been counted, basically changes in
manufacturing costs. Ed explained in more detail how those cost savings
were calculated, but said that the experts would have ample opportunity
to correct any significant mistakes.

Edward brought up the question of de-scoping in phi, but Gunther said
that we worked hard to make a hermetic detector and we would not go there.

Joern asked if it is known if the TPC needs additional anchor points of
the space charges - doubts about the ability to calibrate etc. This will
be a question brought up in next week's TPC expert meeting.

Tony asked if, in light of the $75M version almost certainly not giving
us the full physics capabilities, we are also going to present an
over-the-budget version that preserves as much as possible. Gunther
replied that we have a reference detector which we need to evaluate, and
we can discuss strategy how to bring in other options.  Tony suggested
we should evaluate a contingency all-silicon option in the possible case
of a non-functioning TPC replaced by an additional tracking layer - we'd
need a viable alternative in case the TPC cannot perform to spec.
Gunther replied that we need to refine that strategy, but should discuss
this in another forum.

We adjourned the meeting after that.

Anything left out should be attributed to my note-taking abilities.
Please feel to comment and amend.

Finally, here's the list of people we saw - we had Dave, Ed, Megan, Jin,
Edward, Gabor, Takao, and Eric in the room, and bluejeans says those
others were logged in:
Bill Llope
Joern Putschke
John Lajoie
Rosi Reed
Sourav Tarafdar
Jamie Nagle
Ron Belmont
Jin Huang
Anne Sickles
Huan Huang
Michael McCumber
Dave Morrison
Tom Hemmick
Gabor David
Balazs Ujvari
Christine Aidala
John Haggerty
Sean Stoll
and 3 unidentified dial-ins.


          Martin

-- 
Martin L. Purschke, Ph.D.        ;   purschke AT bnl.gov
                                 ;   http://www.phenix.bnl.gov/~purschke
                                 ;
Brookhaven National Laboratory   ;   phone: +1-631-344-5244
Physics Department Bldg 510 C    ;   fax:   +1-631-344-3253
Upton, NY 11973-5000             ;   skype: mpurschke
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