Scientists at CERN devise an even more powerful particle accelerator than LHC

To smash atoms with unimaginable power.

Cern's Large Hadron Collider (LHC) is back online after a three-year technical shutdown period. The expert scientists at the famous research facility ran the powerful accelerator at the end of April, and Run 3 physics started in early July. The entire process ran at the highest energy level ever achieved in an accelerator.

The LHC experiments are expected to collect so much data on nature at its smallest levels that it is measured in petabytes. While thousands of collaborators are working on the Standard Model of particle physics and are always on the hunt for new physics, things like supersymmetry, dark matter, or even undiscovered new particles, the Cern researchers are preparing the next iteration of the LHC.

Preparing for even more energy

In the later part of the 2020s, the LHC will be operating as the High-Luminosity LHC, an upgraded version of the original accelerator. The upgraded accelerator will collide more protons with more luminosity (the magnifying of the energy of a particle beam, similar to using a magnifying glass to focus the sun's rays and start a fire) than ever done before. Scientists exp[ect to see as many as five to seven times more collisions than before the upgrades. The equipment that detects the luminosity is being improved upon also. Scientists are working on improving the detectors to handle the increased luminosity. The detectors are running now and until the end of 2030 and will reach a factor of data that is 20 times what it is today.

The Compact Muon Solenoid (CMS) is the general purpose detector used at the LHC. The CMS experiment, along with the Atlas experiment, is upgrading several systems. There is a massive effort on the parts of laboratories around the world, including Universities and even the US Department of Energy. All are involved in the updating of the detectors. All this means that CMS scientists will be able to better measure and reconstruct how particles interact with the detector. Increased understanding of how particles and detectors interact could offer more insights and even potential new discoveries into how the universe works.

The detector upgrades

The CMS tracker is the charting process that follows how a particle moves through a magnetic field. The inner pixel detector and an outer strip detector will be completely replaced. The tracker is the part of the CMS detector closest to where LHC proton particles collide, in the heart of the detector. The main reason the upgrades are needed in this innermost area is that the HL-LHC will collide with protons much quicker, and the proton paths will rapidly run into each other and pile up.

One of the newest additions to the detector is the pixel detector. The pixel detector has a finer granularity. Therefore, the rates must be higher, as well as the granularity. This is because the particle paths are happening faster, and the increases in granularity and rates will help to actually detect individual particles. Otherwise, the particles go through the detector so fast that the resulting particle images are just smears.

There are several other layers of detectors. The timing detectors are meant to give precise times to the motion along particle paths. The CMS trigger and data acquisition selects the most potentially interesting collision events and then records the relevant data. It discards the more benign events to keep the huge volumes of imagery information manageable.

The CMS is equipped with calorimeters. The barrel and endcap calorimeters detect and measure the energy signatures of particles. With incredibly fine spatial and outstanding time resolution, the calorimeter allows precise reproduction of the vast numbers of particles produced.

Muon information is collected, which is an essential part of the CMS. As the name Compact Muon Solenoid, the muons from the particle collision can travel a great distance, and this part of the detector sits out the calorimeters. Upgrades include enhanced timing and resolution to detect muons coming off the beam at wider angles.

All of these upgrades and enhancements have been studied by collaborators for years. Now the process of adding them is being performed in stages, with an eye toward completion by late 2029.