I Data Collection Begins: Monitoring the Diphoton Excess

[mfb]

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.

 

[vanhees71]

We are close to even a "supermoon", but that's of course another topic:

http://www.telegraph.co.uk/news/0/what-is-a-supermoon-and-when-can-i-see-the-largest-moon-in-70-ye/

 

[dukwon]

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

 

[Lord Crc]

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... :)

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.