Illustration of two types of long-lived particles decomposing into a set of muons, showing how the signals of the muons can be traced back to the long-lived particle decay point using data from the tracker and muon detectors. Credit: CMS/CERN This search for exotic long-lived particles looks at the possibility of “dark photon” production, which would occur when a Higgs boson decomposes into muons displaced in the detector.The CMS experiment has provided its first search for new physics using information from Run 3 of the Large Hadron Collider. Dark photons are unique long-lived particles: “long-lived” since they have an average life time of more than a tenth of a billionth of a second– a very long lifetime in terms of particles produced in the LHC– and “exotic” due to the fact that they are not part of the Standard Model of particle physics.The Standard Model is the leading theory of the essential building blocks of the Universe, however many physics questions stay unanswered, and so searches for phenomena beyond the Standard Model continue.
Illustration of 2 types of long-lived particles rotting into a set of muons, demonstrating how the signals of the muons can be traced back to the long-lived particle decay point utilizing information from the tracker and muon detectors. Credit: CMS/CERN This search for unique long-lived particles takes a look at the possibility of “dark photon” production, which would happen when a Higgs boson decays into muons displaced in the detector.The CMS experiment has actually provided its first look for brand-new physics utilizing data from Run 3 of the Large Hadron Collider. The new study looks at the possibility of “dark photon” production in the decay of Higgs bosons in the detector. Dark photons are exotic long-lived particles: “long-lived” because they have a typical lifetime of more than a tenth of a billionth of a second– an extremely long life time in regards to particles produced in the LHC– and “unique” due to the fact that they are not part of the Standard Model of particle physics.The Standard Model is the leading theory of the essential foundation of the Universe, however lots of physics questions stay unanswered, and so searches for phenomena beyond the Standard Model continue. CMSs brand-new outcome specifies more constrained limitations on the criteria of the decay of Higgs bosons to dark photons, further limiting the area in which physicists can search for them.Dark Photon Theory and Particle DetectionIn theory, dark photons would take a trip a measurable range in the CMS detector before they decay into “displaced muons.” If researchers were to backtrack the tracks of these muons, they would find that they dont reach all the method to the crash point, since the tracks originate from a particle that has actually currently moved some distance away, without any trace.Run 3 of the LHC began in July 2022 and has a greater rapid luminosity than previous LHC runs, implying there are more collisions happening at any one moment for scientists to analyze. The LHC produces 10s of countless crashes every 2nd, however just a few thousand of them can be kept, as recording every collision would rapidly consume all the readily available information storage. This is why CMS is equipped with a real-time information selection algorithm called the trigger, which decides whether or not a provided accident is interesting. It is not only a greater volume of information that could assist to reveal proof of the dark photon, but likewise the way in which the trigger system is fine-tuned to look for specific phenomena.Advancements in Trigger System and Data Collection”We have actually improved our capability to trigger on displaced muons,” says Juliette Alimena from the CMS experiment. “This enables us to collect a lot more events than before with muons that are displaced from the collision point by ranges from a couple of hundred micrometers to numerous meters. Thanks to these improvements, if dark photons exist, CMS is now a lot more likely to discover them.”The CMS trigger system has actually been essential to this search, and was especially improved between Runs 2 and 3 to look for exotic long-lived particles. As a result, the collaboration has had the ability to utilize the LHC more effectively, getting a strong result using simply a third of the amount of data as previous searches. To do this, the CMS group fine-tuned the trigger system by including a brand-new algorithm called a non-pointing muon algorithm. This enhancement suggested that even with just four to five months of data from Run 3 in 2022, more displaced-muon occasions were taped than in the much bigger 2016– 18 Run 2 dataset. The brand-new protection of the triggers significantly increases the momentum varieties of the muons that are gotten, permitting the team to check out brand-new areas where long-lived particles might be hiding.Future Plans and Continued ExplorationThe CMS team will continue using the most effective techniques to examine all data taken in the staying years of Run 3 operations, with the objective of more checking out physics beyond the Standard Model.
