Wednesday, October 31, 2018

Large Hadron Collider Run 2 Ends Soon

The Large Hadron Collider (LHC) will shut down in December and won't start up again until 2021. In the meantime there will be basically no new high energy physics experimental data and scientists will have to pour over the data that has been already collected instead. 
Since 2015 the LHC experiments have been taking data from proton-proton collisions at 13 TeV. This is “Run 2” of the LHC, “Run 1” was at the lower energy of 8 TeV. The proton-proton Run 2 ended this morning, with the LHC shifting to other tasks, first machine development, later heavy ions. It will shut down completely in December for the start of “Long Shutdown 2 (LS2)”, which will last for over two years, into early 2021. During LS2 there will be maintenance performed and improvements made, including bringing the collision energy of the machine up to the design energy of 14 TeV. 
ATLAS is reporting 158 inverse fb of collisions delivered by the machine during Run 2, of which 149 inverse fb were recorded, the CMS numbers should be similar. Most data analysis reported to date by ATLAS and CMS has only used the 2015 and 2016 data (about 36 inverse fb) although a few results have included data through 2017 (about 80 inverse fb). My impression is that for many searches they have been waiting for the full run 2 dataset to be available. Perhaps results of searches with the full dataset might start becoming available by the time of summer 2019 conferences. 
The LHC run 3 is planned for 2021-2023, producing perhaps 300 inverse fb of data, results perhaps available in 2024. It will thus be quite a long time after run 2 results start appearing before better ones due simply to more data become available.
From Not Even Wrong.


neo said...


you might find this interesting
On Thursday 1 November, Large Hadron Collider (LHC) physicists will be discussing the fact that they may have found a new and unexpected new particle.

"I'd say theorists are excited and experimentalists are very sceptical," CERN physicist Alexandre Nikitenko told The Guardian. "As a physicist I must be very critical, but as the author of this analysis I must have some optimism too."

The telltale signal is a bump in the data collected by the LHC's Compact Muon Solenoid (CMS) detector as the researchers were smashing together particles to look for something else entirely.

When heavy particles - such as the Higgs Boson - are produced through particle collisions, they decay almost immediately. This produces a shower of smaller mass particles, as well as increased momentum, which can be picked up by the LHC's detectors.

When these particle showers produced pairs of muons (a type of elementary particle that is similar to an electron but with a much higher mass), the team sat up and paid attention. But what they traced these pairs back to was, to be very scientific about it, mega weird.

The new and unknown particle that seems to have produced the muons has a mass of around 28 GeV (giga-electronvolts), just over a fifth of the mass of the Higgs boson (125 GeV)."

andrew said...

Count me among those who find that bump so unlikely to be real that it isn't really even worth reporting at this point.

neo said...

probably true,

in other news Abhay Ashketar wins an Einstein award for Loop Quantum Gravity

and a graduate student wins an award also for Loop Quantum Gravity plane waves

I double checked with Bee that Loop Quantum Gravity is one of QG candidates that

1- is compatible with DeSitter spacetime
2- can reproduce BH entropy