Piyare Jain, a University of Buffalo physicist and Gurmukh Singh a fellow researcher succeeded in finding the controversial no-charge particle ‘axion’.
Its existence was first suggested by Prof. Jain in a paper in 1974. It was a widely accepted theory in the 1970’s however, after a long and fruitless search for this elusive particle, theorists started doubting its existence and it was labeled as ‘phantom’.
This axion has a mass of 6-20 MeV and a life span of about 10^(-13) seconds. According to Jain the axion was undetected even at the CERES experiment at CERN, Geneva - the world’s largest particle physics laboratory - because of its very short life span.
He then used a visual detector, which would act as the target and the detector in the experiment. At very high temperature and pressure using a lead beam at 160 A GeV, axion particles were finally detected.
These particles are crucial to Quantum Chromodynamics and recently are considered to be leading constituents of dark matter.

Ref: PhysOrg, Axion and Dark Matter, Official paper

Source: Slashdot