LPC meeting summary 08-11-2021 - final
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LPC meeting summary 08-11-2021 - final |
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Main purpose of the meeting: 2022 schedule and input to Evian workshop.
Introduction (Brian)
1) LS2 schedule:
2) beta* levelling during Run 3: 5% jumps leads to 10 jumps, every 30 minutes.
Is lumi during the jump good or will that be rejected?
3) Evian@CERN: what we plan to show
Q&A
Remark from Richard (SND): may want to use opportunistic LHC stops (4-5 hours) to change emulsions
Joerg (ATLAS): are MD periods still fixed in the 2022 schedule? A: no
Lorenzo (LHCf): is the LHCf run now preferred to have after the "delayed TS1" or after TS2?
General preference to do the run when radiation levels are not yet too high.
A: depends on where TS1 will be in the new schedule
Round Table:
Federico (LHCb):
- all objectives of pilot beam test have been achieved (and beyond)
- VdM scans: requirements similar to 2018. Important to have DOROS BPMs in good shape. SMOG2 should be availalbe as well, hopefully LHCb BGI.
In principle, as long as PLUME and VELO are present in LHCb at the time of the VdM scans, not depending on the full detector availability.
- pp reference run: would like at least 25 pb-1
- Run 3 conditions:
- agreed to have V x-angle from 2023 onwards, with MD in 2022
- request multiple SB periods at 450 GeV with few colliding bunches for commissioning
Q&A:
Brian: for the VdM programme, LHCb has no need to have (close to) high lumi bunches?
A: no
Taku (ALICE)
- Happy with the pilot beam test
- VdM
would like it at least one month into the high-energy running to make sure (so after TS2 preferred)
- pp reference run:
- 5 days: 3pb-1 target, 1MHz with 50% efficiency
- mu as low as possible (depends on #bunches)
- Run 3 requests:
SB at 450 GeV (at higher rate than now) would be useful
Q&A:
Filip: will there be another request for pp reference data during Run 3 (after 2022)?
A: will need it again in 2024.
Trevor (ATLAS)
-Thank you for the pilot beam test, was very succesful
- pp reference run:
- need ~ 260 pb-1 over all of Run 3 (6 nb-1 of PbPb data)
- for 2022 (2 nb-1 of PbPb data), this would mean 86 pb-1
- ZDC input for LHCf run:
ZDC are planning to install 3 hadronic modules in each TAN during LHCf run in 2022.
To protect fused silica for HI running in late 2022, ZDC needs to avoid unwanted exposure to high lumi proton beams
- beta* leveling:
if jumps are not more than 5%, see no reason why the lumi during the jump would be marked as bad.
Q&A:
Brian: do you have limitations on mu for the pp reference run?
A: to be checked.
Gianni (CMS)
* beta* leveling: 5% steps have no impact on data-taking efficiency
* LHCf run: CMS lumi group is investigating possibility to parasitically use the LHCf 2022 run for a VdM length scale scan.
Which crossing angle will be used for this fill?
* CMS is considering the possibility to use TOTEM T2 detector for HI collisions as a trigger.
- since T2 cannot be installed for fills with PU>1, would require to swap the pp ref run with the high beta* and to delay the TS3 by a few days
(sequence: pp ref —> TS3 —> high bet* —> PbPb)
- not yet a formal request, still will require studies in CMS, but want to know if there is a showstoppers from LPC for this hypothesis
* pp reference run:
- need ~ 150 pb-2 to match 2.3 nb-1 of PbPb lumi
- max 7 days including setup should be devoted to this
- during 2017 pp ref run 300 pb-1 were delivered in 7 days with an average PU of 3
Q&A:
Brian: shoulnd’t ZDC be installed during the TS in order to take the pp ref run?
A: yes, but only takes ~1 hour. But indeed to be studied.
Witold: does CMS still need some high lumi run just before the VdM, or no longer needed?
A: will check with David Stickland
Comment from Lorenzo: crossing angle during LHCf run will be 290 murad