sPHENIX discussion of physics

[Cameron Thomas Dean <cameron.dean AT cern.ch>]

Dear all,

Here are the minutes of todays meeting.

Cheers,
Cameron, Tony, Jin and Marzia

HF/Q minutes, Thursday September 22nd 2022, 10am ET

 

Introduction

 

Cameron - A quick reminder that the NSAC long range plan town hall begins tomorrow. The meeting is hybrid. Please join if you can.

 

Jin - For analysers, we are geenerating D0 jet samples now.

Cameron - Yes, Chris kicked this off last week and we aim to have 10M events with an event pT min of 5 GeV and jet pT min of 10 GeV. They are available under type 16 in the catalogue.

 

MDC2 Run 40 D0 Reconstruction - Thomas Marshall

 

slide 2 - Thomas - Is 14.5% selection efficiency good?

          Cameron - It depends on the cuts used so it's hard to tell just now.

 

slide 3 - Jin - What cuts were used to calculate the geometric and kinematic acceptance?

                                  Thomas - A D0 pT > 0.5 GeV and tracks with |eta| < 1.1

                                  Jin - It could be useful to have the cuts on the daughter track whose pT is directly related to the acceptance

 

slide 4 - Jin - It could be better to cut on the daughter |eta| < 0.5. This will check if we have an additional loss from the tracking efficiency which will give us more information on the acceptnace.

         

General - Jin - Can you upload your macros for making the efficiency plots? This is an important study for many other analyses

          Thomas - I'll aim to upload them this week

 

          Joseph - What training branches were used in the ML study? Likely this will be in the macro upload, could you provide a link?

          Thomas - Yes, I will pass a link via mattermost and likely put them in our analysis repository. Which channel should they go in?

          Cameron - Either hf-MDC or hf-D0, I'll provide links.

          Chris - This info should go in our wiki

          Thomas - I can add info to our wiki.

 

          Zhaozhong - Can we track to 0.2 GeV or below?

          Tony - That depends on the required efficiency

          Joe – We see that loopers exist at around 0.15 GeV

          Tony – Michael Peters new work on the seeding should improve the low pT region.

 

EvtGen - Zhaozhong Shi

 

slide 4 "Existing Scheme with B_s0 Decay" - Jin - The current implementation shown here is not what we want to implement in Geant4 (see "Desired Scheme" on next slide). This is also the current implementation of the pythia6 external decayer in Geant4. This would result in any decay with a cascade (such as B-hadron decays) being handles incorrectly. We can't launch the b sample until we have EvtGen implemented.

                                                                                                                                                                                Zhaozhong - Do we need to fix the pythia6 decayer?

                                                                                                                                                                                Jin - No, we'll use our EvtGen implementation

 

slide 6 - Wei - On the 1st bullet, is the B_s0 handled by EvtGen and the phi handled by Geant?

                                Zhaozhong - Yes

                                Wei - So everything heavy flavor related is handled by EvtGen?

                                Zhaozhong - Yes

                                Wei - For multibody decays, do we trust Geant to handle light flavor correctly?

                                Zhaozhong - Good question, we know that HF is handled correctly but, so far, light flavor seems OK. We would need more studies to confirm.

 

slide 9 - Jin - The check on the vtx_x position is not necessary to validate EvtGen and Geant as they won't have the same vertex. Geant4 will propogate the particle according to the detector simulation. You only need to check the final states in Geant4, in this case the D0 and D+

 

From: sPHENIX-HF-jets-l <sphenix-hf-jets-l-bounces AT lists.bnl.gov> on behalf of "Dean, Cameron via sPHENIX-HF-jets-l" <sphenix-hf-jets-l AT lists.bnl.gov>
Reply-To: "Dean, Cameron" <cdean AT bnl.gov>
Date: Tuesday, September 20, 2022 at 10:02 PM
To: "sphenix-physics-l AT lists.bnl.gov" <sphenix-physics-l AT lists.bnl.gov>, "sphenix-hf-jets-l AT lists.bnl.gov" <sphenix-hf-jets-l AT lists.bnl.gov>, "sphenix-upsilon-l AT lists.bnl.gov" <sphenix-upsilon-l AT lists.bnl.gov>
Subject: [Sphenix-hf-jets-l] New time: Joint HF/Quarkonium TG meeting September 22nd at 10am ET

 

Dear sPHENIX colleagues,

 

Please join us for our next joint Quarkonium/HF meeting at our new time on Thursday September 22nd at 10am ET.

 

We will have the following agenda:

 

• Introduction: co-convenors
• First look at MDC2 run 40 full data: Thomas Marshall
• EvtGen decayer: Zhaozhong Shi

 

The indigo agenda can be found at https://indico.bnl.gov/event/17042/ and the zoom link is https://bnl.zoomgov.com/j/1613938007?pwd=QjYzUnpYQ2xNZWZLSy9qd3Z4dFpzZz09 

 

We look forward to seeing you there.

 

Best regards,

Cameron, Tony, Jin and Marzia