The Y(4140) particle is an electrically neutral exotic hadron candidate that is about 4.4 times heavier than the proton.
[3] The existence of the particle has been confirmed by members of the CMS collaboration at the Large Hadron Collider on November 14, 2012[4][5] and by the DØ experiment at the Tevatron on September 25, 2013.
[6][7] The Belle experiment[8] has searched for this particle but found no evidence for its existence.
The LHCb experiment observes a peak at the same position in the J/ψΦ invariant mass, but it is best described as a Ds±Ds∗∓ cusp, and is much broader than the previous measurements of the Y(4140).
[9][10] The Particle Data Group has renamed Y(4140) to follow naming conventions to X(4140).