Chinese And Japanese Researchers Find Evidence Of A New Particle

Possible structure with four quarks in Z c (3900).Other particles like pions, has two quarks, such as protons or three.

Credit: APS

The KEKB particle accelerator  in Japan, and the detector Beijing Spectrometer III (BES III) collider in China have found signatures which could be a new particle called Z c (3900).

The two scientific collaborations,  of Asian and other researchers around the world, published their finding in the journal Physical Review Letters . Together, they have identified 460 examples of the new structure.

The recorded data suggest that Z c (3900) could be an unknown type of matter, consisting of four quarks. So far only known groups of two quarks or antiquarks, as the pions, for example, or of three quarks, such as protons have been found.

With the current information, the particle appears to have electric charge and at least one charmed quark and an  anti-charm quark. The quartet is supplemented by a top quark and an anti-top quark, scientists suspect.

What to now confirm is that a four quark particle not for example the interaction of two quark with a pair each, or sporadic connections such essential constituents matter.

The discovery of Z c (3900) was the result of research with another particle, Y (4260), discovered in 2005. When considering its disintegration in the two colliders, physicists noticed a peak energy of about 3.9 gigaelectronvolts, about four times the weight of a proton. This suggests the existence of four-quark particle, a novelty in particle physics to be demonstrated.

Citation: M. Ablikim et al. (BESIII Collaboration), “Observation of a Charged Charmoniumlike Structure in e + e-→ π + π-J / ψ at √ s = 4.26 GeV.” ZQ Liu et al. (Belle Collaboration), “Study of e + e-→ π + π-J / ψ and Observation of a Charged Charmoniumlike State at Belle”. Phys Rev. Lett. 110: 252001 and 252002, June 17, 2013. Papers available.