How Scientists Identified X(2370)The X(2370) particle was first observed in 2011 during experiments involving J/ψ particles. The first important clue was the particle's mass. But matching the predicted mass was not enough. A glueball with the properties expected for X(2370) occupies a mass range where other particles made from quarks can have similar quantum characteristics. Researchers are still searching for other possible states, including a scalar glueball expected at a lower mass and a tensor glueball predicted at a mass near 2.2 GeV.