Data Collection Begins: Monitoring the Diphoton Excess

  • Context: Undergrad 
  • Thread starter Thread starter mfb
  • Start date Start date
  • Tags Tags
    Data
Click For Summary
SUMMARY

The LHC has commenced data collection with initial luminosity levels starting at 0.05% of the design value, gradually increasing to 30% as of the latest updates. The process involves scrubbing to clean the beam pipe and mitigate electron cloud effects, which can lead to overheating of superconducting magnets. The goal is to ramp up to 2700 bunches for optimal data collection, with significant milestones set for the ICHEP conference in August. Current integrated luminosity for ATLAS and CMS stands at 290/pb, with ongoing adjustments to address vacuum issues in the preaccelerators.

PREREQUISITES
  • Understanding of LHC operational parameters, including luminosity and bunches.
  • Familiarity with the concept of scrubbing in particle accelerators.
  • Knowledge of electron cloud effects and their impact on superconducting magnets.
  • Awareness of integrated luminosity and its significance in high-energy physics experiments.
NEXT STEPS
  • Research the LHC scrubbing process and its effects on beam stability.
  • Learn about the electron cloud phenomenon and mitigation strategies in particle accelerators.
  • Investigate the implications of integrated luminosity on physics analyses in experiments like ATLAS and CMS.
  • Explore the operational challenges faced by the LHC, particularly regarding vacuum issues in preaccelerators.
USEFUL FOR

Particle physicists, accelerator engineers, and researchers involved in high-energy physics experiments, particularly those focusing on data collection and analysis at the LHC.

  • #121
The luminosity just depends on beam parameters, not on details of the collisions (which happen in the kHz range anyway, not on the timescale of those fluctuations). I don't know where the fluctuations come from - could be some calibration issue with the measurement, or very frequent changes of the beam overlap by the machine operators.
The LHC registered the earthquake in New Zealand. It lead to a small deformation of the ring which changes the beam energy a tiny bit. This is the result. The long-term sine modulation are the tides. They are quite strong because we are close to a full moon.
 
  • Like
Likes   Reactions: OmCheeto
Physics news on Phys.org
  • #123
Lord Crc said:
Potentially silly question: with the p-Pb run under way I'm looking at Vistars and wondering why the instantaneous luminosity of ALICE has such great fluctuations compared to the other detectors.

Is it just due to each collision having a much wider range of results depending on "how well" each proton hits the nucleus? I'm thinking bowling here.

This is what luminosity levelling looks like when you zoom in on the y-axis scale.

Here's an example when they tried levelling ATLAS and CMS

fqiFbOZ.png
 
  • Like
Likes   Reactions: Lord Crc and mfb
  • #124
mfb said:
The luminosity just depends on beam parameters, not on details of the collisions (which happen in the kHz range anyway, not on the timescale of those fluctuations). I don't know where the fluctuations come from - could be some calibration issue with the measurement, or very frequent changes of the beam overlap by the machine operators.

As the song goes, I should have known better... :)

mfb said:
The LHC registered the earthquake in New Zealand. It lead to a small deformation of the ring which changes the beam energy a tiny bit. This is the result. The long-term sine modulation are the tides. They are quite strong because we are close to a full moon.

Really interesting, thanks for sharing.
 

Similar threads

Undergrad The Latest Higgs Boson Mass Measurement
  • · Replies 13 ·
Replies
13
Views
5K
  • Sticky
Undergrad What progress has been made in Belle II collisions at SuperKEKB in 2021?
  • · Replies 28 ·
Replies
28
Views
11K
Undergrad What are the challenges faced by LHC in the initial data-taking of 2017?
  • · Replies 109 ·
4
Replies
109
Views
18K
Undergrad LHC finishes proton-proton collisions in 2018
  • · Replies 57 ·
2
Replies
57
Views
15K
Undergrad Is Toponium a Reality Despite Top Quark's Rapid Decay?
  • · Replies 9 ·
Replies
9
Views
988
Undergrad Progress In Calculating The HLbL Contribution To Muon g-2
  • · Replies 0 ·
Replies
0
Views
2K
Graduate LHC about to restart - some frequently asked questions
  • · Replies 69 ·
3
Replies
69
Views
14K
Undergrad B -> s µµ decays: Current status
  • · Replies 49 ·
2
Replies
49
Views
12K
Undergrad What false hints of new physics were most notable?
  • · Replies 30 ·
2
Replies
30
Views
8K
Undergrad What Key Issues Should Cosmologists Address in the ΛCDM Model?
  • · Replies 1 ·
Replies
1
Views
3K