CERN Experiment with Indian Scientists Detects New Subatomic Particle

The Large Hadron Collider at CERN has detected a new subatomic particle that does not fit neatly into the Standard Model of physics, with Indian physicists from TIFR Mumbai and IIT Madras playing a key role in the discovery. The particle, temporarily designated X(6900), appears to be a tetraquark — a bound state of four quarks — with properties that challenge existing theoretical predictions.

What Makes This Special

While tetraquarks have been detected before, X(6900) is unique because it contains two charm quarks and two charm antiquarks in a configuration that theoretical models predicted should be unstable. Its unexpectedly long lifetime of approximately 10^-20 seconds suggests an unknown binding force or mechanism that current physics cannot fully explain.

The Indian team, comprising 42 physicists from TIFR and IIT Madras, was responsible for the data analysis algorithms that identified the particle's signature in the collision debris. Their machine learning-based approach, developed over three years, proved crucial in separating the particle's signal from the enormous background noise of LHC collisions.

"Finding a particle that shouldn't exist according to our best theories is exactly what we live for as physicists. X(6900) is either telling us the Standard Model is incomplete, or there's new physics hiding in plain sight," said Professor Naba Mondal of TIFR, who co-leads the Indian CERN contingent.

The discovery has been submitted for publication in Physical Review Letters and is undergoing peer review. If confirmed, it would be a significant step toward understanding the strong nuclear force — one of the four fundamental forces of nature — and could point toward physics beyond the Standard Model. India has been a significant contributor to CERN's research programme since 1991.