Ghostly Particles in Particle Colliders
In a groundbreaking discovery earlier this year, scientists successfully detected neutrinos generated within a particle collider, shedding light on these mysterious subatomic particles often referred to as “ghost particles.” Neutrinos are peculiar in that they effortlessly pass through matter, barely interacting with it.
A Historic Observation
This achievement marks the first direct observation of neutrinos produced in a collider, offering valuable insights into their formation, properties, and their role in the Universe’s evolution. The findings were presented at the 57th Rencontres de Moriond Electroweak Interactions and Unified Theories conference in Italy in March 2023, and two peer-reviewed papers have recently been published to confirm the detection.
The Elusive Neutrinos
Neutrinos rank among the most abundant subatomic particles in the Universe, second only to photons. However, they possess no electric charge, nearly zero mass, and exhibit minimal interaction with other particles. Despite their near-ubiquity, they remain elusive to detection. Countless neutrinos are currently passing through your body, unnoticed.
Neutrinos in Action
Neutrinos are generated in energetic environments like nuclear fusion within stars and supernova explosions. While their mass is incredibly small, physicists suspect it may influence gravity, although neutrinos are not considered a candidate for dark matter.
Ghostly Interactions
Although neutrinos interact with matter infrequently, occasional collisions with other particles can produce faint bursts of light. Special detectors, such as IceCube in Antarctica, Super-Kamiokande in Japan, and MiniBooNE at Fermilab in Illinois, can capture these bursts.
High-Energy Neutrinos
Researchers have been keen to study neutrinos produced in particle colliders due to the exceptionally high energies involved. These collisions offer unique insights into deep space and particle astrophysics.
FASERnu Detector
The breakthrough was made possible with the FASERnu detector at the Large Hadron Collider (LHC). This detector, comprising millimeter-thick tungsten plates interspersed with emulsion film layers, is designed to enhance the chances of neutrino interactions. The detector contains 730 emulsion films and around 1 ton of tungsten. When neutrinos collide with tungsten nuclei, they produce particles that leave tracks in the emulsion layers, much like ionizing radiation in a cloud chamber.
Confirmation of Discovery
Six neutrino candidates were initially identified in 2021, and the recent data from the upgraded LHC’s third run has confirmed their discovery with an impressive significance level of 16 sigma. This level of significance indicates that the likelihood of these signals occurring by random chance is exceedingly low.
Ongoing Research
The FASER team continues to analyze data collected by the detector, with Run 3 of the LHC expected to run until 2026. Physicists anticipate thousands more neutrino interactions, as the full potential of the collider is finally being harnessed for neutrino research.
In summary, this historic discovery of neutrinos in particle colliders opens up a new realm of possibilities in our quest to understand the Universe’s deepest secrets.
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