Chinese scientists find evidence of new particle Zc (4025)  

科学家发现新粒子 对完善宇宙物质理解具重要意义

继去年发现一个命名为Zc(3900)的新的共振结构之后，科学家们最近又在北京正负电子对撞机的北京谱仪Ⅲ(BESⅢ)实验中，观测到一个新的粒子(共振结构)Zc(4025)。 [查看全文]

Beijing (CNS) – A group of scientists at the Chinese Academy of Sciences have observed a new particle – charmonium-like resonance Zc (4025) — in an experiment with the Beijing Spectrometer III (BES III) detector.

The discovery of Zc (4025), along with Zc (3900) last year, provides significant experimental evidence that physical forms different than the normal baryons or mesons exist in the natural world, according to the scientists.

Last March, BES III researchers announced that they had observed the new particle Zc (3900) containing four-quark matter, a charm quark, an anticharm quark, and a pair of electric charges, which might be a hadron that scientists have been looking for.

Experts said that Zc (4025) decays into two final states, each containing two quarks, indicating that one Zc (4025) has at least four quarks — similar to Zc (3900) — and that Zc (4025) is likely to be the excited state of Zc (3900).

Discoveries of the final states of Zc (4025) have provided an experimental basis for studying characters of the Zc particle family, the scientists added.

It is also significant for people to understand the fundamental structure of matter in the universe, scientists said.

A research paper of the discovery was published in the latest Physical Review Letters.