Minutes and Summary

Main purpose of the meeting: Data taking progress (including plan for increased intensity); First look towards PbPb; 2026 questions

LPC minutes 13 October 2025

Present (P = in person): Chris Young (P), Chiara Zampolli (P), Andrej Gorisek (P), Flavio Pisani (P), Riccardo Longo, Robert Muenzer (P), Silvia Pisano (P), Flavio Pisani (P), Paula Collins (P), Witold Kozanecki, Andres Dellanoy, Matteo Solfaroli Camillocci, Dragoslav Lavic, David Stickland (P), Joanna Wanczyk, Jorg Wenninger (P), Filip Moortgat (P), Xavier Buffat, Tomasz Bold, Matthew Nguyen

Introduction (Chris Young)

Chris Young: by the LHCC, the experiments might still be unsure about PbPb vs pPb in 2026 since we’ll be only 1 week into the HI run. But by the end of November we should have a pretty good idea.

Chris Young: is the 2FA still causing problems after the workaround sent by Michi?

Flavio Pisani: I need to check. the workaround was not working at that time because it was disabled and now it should be back, but I should check. 

Chris Young: if there are problems, we have contacts in IT and we could talk to them.

Filip Moortgat: it won’t change much, even the Director of Research went to talk to them and it did not work. It is very frustrating.

Flavio Pisani: last week, after the MD, we almost delayed injection because the experts could not log in to change the regime. It took the piquet 30 minutes to log in.

Chris Young: was this was not an intentional change by IT, but an accidental thing?

Flavio Pisani: I think the way they implemented the 2FA for rDesktop, even if you are at CERN, for certain machines that are behind certain gateways, you need the 2FA. 

Andrej Gorisek: this is for all terminal servers except the CERN terminals. 

Flavio Pisani: e.g. for the vacuum terminal service you have to go through the 2FA. In LHCb most of the things are on linux and are not affected but some are not, like DSS (Detector Safety System). 

Chris Young: was this something done intentionally after the MD?

Flavio Pisani: this was done when they put in place the 2FA at the end of September. 

Filip Moortgat: the problem appeared from the start. What was not affected is the log-in to lxplus, but if you had to log in to the terminal servers, that was full of mistakes. At present, for CMS it seems that it is working. It was not on Friday though, so it took 10 days. This includes also the safety monitoring, not working for 10 days.

Flavio Pisani: also for us, the DSS was not accessible, even if we have some automatic actions.

Robert Muenzer: same for ALICE, we are collecting all the tickets. The issues were mainly that the connection was so slow. 

Chris: could it be useful if we arrange a meeting between the IT guys and you RCs?

Flavio Pisani: it might not change much, but we can try. 

Robert Muenzer: they will not revert it. 

Chris Young: we can send them an email and invite them here. 

 

LHCb (Paula Collins)

Chiara Zampolli: so the intervention that was planned for MD3 did not succeed?

Flavio Pisani: the problem is that we did not have all the pieces needed, even if they had said we’d have had everything. The main thing is that or SciFi tracker is running at -40 instead of -50, probably with a partial fix they could have run at -50, but then it was agreed that -40 deg was fine. Now it is true that we have limited redundancy in the system in case something breaks.

Chris Young: for the SMOG, you said that the limitation of H (which will finish in the coming days) is the size of the bottle. So if we’d have an access on Wed, would you put a new one?

Paula Collins: no.

 

ALICE (Robert Muenzer)

Note: Beam 1 is A side, which means Left side, Beam 2 is C side, which means Right side.

Jorg Wenninger: about the bkg test in ion, we’ll need 1.5 d of ion setup before we can do the test.

Chris Young: it seems that there will not be a quench test, so probably the ion setup will not move in the schedule. 

Jorg Wenninger: I tried to fill in the spreadsheet the activities, the bkg test is after Sun 12 pm. 

Chris Young: for the ZDC, could you use an access on Wed 29.10? It would be better to do it outside the MD period.

Robert Muenzer: we will check with the experts that are coming for the MD4.

Paula Collins: what will happen during the bkg test? How long will we have collisions?

Jorg Wenninger: there will be collisions everywhere, and they will scan some knobs, possibly TCTs, your luminosity on/off (not to switch it off, but to understand the correlation). It will be single bunches.

Chris Young: the beam intensity will be low and we will be ADJUST rather than STABLE BEAMS.

Robert Muenzer: we should try to see if in the baseline configuration we see any hint of background. If this is not the case we will probably not do an intense scan with knobs.

Paula Collins: when will the MD4 start?

Jorg Wenninger: I also thought it was shortened. 

Chris Young: in the latest version of the program it was 8h shorter, but then MD3 ended 8h earlier, so it makes it even. There is then the idea by Jan to move one day to 2026, but it needs to be approved by the LMC next time. Probably it will be approved, and MD4 will start on Tuesday morning.

David Stickland: so the first blue block on the MD should become pink. [yes]

Robert Muenzer: the ALICE final statement for pPb is still under discussion.

 

CMS (Filip Moorgat)

Filip Moortgat: request to have some commissioning activities with collisions the last 2 days of ion setup (after ZDC insertion). Will there be collisions?

Jorg Wenninger: yes, but they might be short, in case you need, you should ask for extra time.

Filip Moortgat: the idea is not to interfere with the setup.

Chris Young: there should be loss maps.

Filip Moortgat: PbPb vs pPb: discussions still ongoing, but what is on the intro slides is at the moment still valid.

 

ATLAS (Andrej Gorisek)

Filip Moortgat: also CMS will ramp down the magnets as soon as possible at the end of the data taking.