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Scientists at CERN Unveil Ultra-Rare Particle Decay Discovery
Recent research conducted at CERN has unveiled an exceptionally rare particle decay process, marking a significant step forward in probing the depths of particle physics and potentially uncovering new phenomena beyond the established theories.
During a presentation at a CERN EP seminar, the NA62 collaboration announced the first experimental observation of a rare decay of the charged kaon, K+, into a charged pion (π+) and a pair of neutrinos (νṽ), a process represented as K+ → π+νṽ.
This specific decay event is noteworthy for its rarity, as the Standard Model of particle physics suggests that less than one in ten billion kaons undergo this transformation. The NA62 experiment was meticulously designed to detect this rare occurrence.
Cristina Lazzeroni, a Professor of Particle Physics at the University of Birmingham, expressed her excitement, stating, “With this measurement, K+ → π+νṽ becomes the rarest decay established at discovery level—the famous 5 sigma. This challenging analysis reflects our excellent teamwork, and I am incredibly proud of this significant result.”
Kaons are generated using a high-intensity proton beam from the CERN Super Proton Synchrotron (SPS), which strikes a stationary target, resulting in a stream of nearly one billion secondary particles per second. Of these, about six percent are charged kaons. The NA62 detector is adept at identifying and measuring each kaon along with its decay products, although neutrinos are inferred from missing energy metrics.
Professor Giuseppe Ruggiero from the University of Florence remarked, “This achievement is the culmination of a decade-long project. Investigating rare natural phenomena with probabilities around 10^-11 is both captivating and demanding. After extensive and meticulous efforts, we have been rewarded with a remarkable finding that fulfills our long-term expectations.”
The findings stem from a compilation of data collected during the NA62 experiments conducted in 2021 and 2022, alongside earlier results from 2016 to 2018. The recent data collection was made possible by significant upgrades to the NA62 apparatus, which allowed operations at a 30% higher beam intensity, equipped with enhancements in detection technology.
These hardware improvements and refined analysis methodologies facilitated the identification of signal candidates at a rate 50% higher than previous collections, along with new tools to minimize background noise in the data.
A key contributor to the NA62 experiment, Professor Evgueni Goudzovski from the University of Birmingham, shared that their group has been integral to the project since its design phase began in 2007. He emphasized the importance of nurturing talent, highlighting that both the current physics coordinator and the convener responsible for the K+ → π+νṽ measurement are former Ph.D. students from Birmingham. “It is a privilege to lead such a vibrant and collaborative team,” he added.
The research team’s focus on the K+ → π+νṽ decay is attributed to its sensitivity to potential new physics beyond the Standard Model. This decay process represents a compelling avenue for exploring phenomena that current theories may not fully account for.
The estimated occurrence rate for kaons decaying into a pion and two neutrinos stands at approximately 13 in 100 billion, which aligns with Standard Model predictions but suggests a 50% increase. This discrepancy hints at the possibility of new particles that could enhance the decay probability, although additional data will be necessary to substantiate this theory. The NA62 experiment is actively gathering further data, with hopes of confirming or refuting the existence of new physics in these decay processes over the coming years.
More information: CERN seminars: indico.cern.ch/event/1447422/
Citation: First observation of ultra-rare particle decay could uncover new physics (2024, September 24) retrieved 24 September 2024 from https://phys.org/news/2024-09-ultra-rare-particle-decay-uncover.html
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