Minutes and Summary

Main purpose of the meeting: The meeting is mostly dedicated to the review of the triplet incident, the schedule restart and the ion run setup.

 

Federico (Introduction)

Comment from Silvia: program for ATLAS (low mu) in // to ALICE/LHCb scan → that would imply CMS to be head-on.

 

Jorg (Schedule proposal)

Valentina Avati commented that regarding the very high beta* run from the point of view of the reconstruction, one day may be enough. If things are not good enough, however, TOTEM asks if a possible fall back solution could be in place. Daniele Mirachi confirmed that now we have a solid starting point that we can use to iterate to study the situation. One pot is currently problematic. Nevertheless, there are ideas on where to look (the easiest most trivial bit is to open the pot a bit and put it in the shadow): the best solution is to work on the optics and solve it properly. 

 

Maciej asked if on set up with protons there is need of BBA. Jorg responded that this setup is roman-pot less. Also Jorg commented that the assumption is that there are no Roman Pots in VdM.

 

Reyes commented that the BLM teams asked to split the pp reference run in two bits that would allow it to analyze the data. Jorg commented that ideally this could be done between the VdM in ALICE/LHCb and the very high beta* run. 

 

Gianni asked what the ppb in pp ref would be realistically. Jorg suggested that it would be better to stay conservative on the ppb (1.4x10^11 ppb) and increase the rate of ramp-up rather than work on injectors to increase ppb. VdM is included in the pp reference run. Agreement is that the more precision is required in VdM in pp ref, the less integrated luminosity is possible. 

 

Niels asked if LHCb can inject SMOG in the very high beta* run. Jorg confirmed that in principle this is no issue. Sune said that it would be better to have the non colliding bunch, colliding in LHCb. To be clarified offline.

 

Witold commented that what is important in the pp reference run VdM is the beam-beam parameter that is independent from beta*. Emittance would really need to be around 3 microns to satisfy the VdM requirement. 

 

Maciej asked when would be a good moment to do ZDC installation. Jorg’s proposal will be shown at the LMC on Wednesday so in that case technical coordination would be involved. However, apart from Sector 78 that will be locked, the rest of the accelerator can be accessed without problem by following the usual access rules. 

 

Andrea (ALICE)

Clarification on slide 5. ALICE commented that they require Stable Beams, not just collisions. 

 

Reyes asked to clarify if ALICE will take data with both polarities. Andrea confirmed that if the large crossing angle can be inserted without too much overhead, ALICE would prefer to run with both polarities. Reyes followed up with 

 

Andrea reiterated that early Stable Beams are really needed as the incident stopped the commissioning plan.

 

Niels (LHCb) 

Request SMOG to be injected in the very high beta* run, if no colliding bunch in LHCb. 

 

Andrea (CMS)

Andrea added verbally that currently CMS does not require INDIVs. Confirmation will await the next LPC. 

Federico asked for the need of SB in CMS. CMS will get back to us. 

 

Silvia (ATLAS)

Schedule option will have at most one week of uncertainty. Experiments should plan to be ready earliest one week before the 11th of September. 

 

Federico, Filip and Jorg confirmed that we can consider the pp data taking at high intensity and high pileup finished for 2023. 

 

Filip confirmed that INDIVs cost roughly 8% (two trains). The idea is to reduce the number of PbPb fills with INDIVS to a few per week to minimize the impact and collect integrated luminosity. 

 

AoB

Niels asked if there any limitations of access to LHCb? Jorg thinks not. Cavern closure to be confirmed soon, but roughly a few days before.

 

Reyes asked to confirm that ATLAS mu will be 4. Filip and Federico will calculate how much integrated luminosity will be reached with ppb of 1.4x10^11 ppb instead of 1.6

 

Reyes asked if this triplet accident will affect the OO run. To be discussed as we get close to the end of the  year.