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New particle x (2600) found in BESIII experiment of Beijing Spectrometer

Recently, the Beijing Spectrometer BESIII experiment international cooperation group has used the collected 10billionJ/ψ  According to the experimental data, a new particle x (two600) was observed for the first time. The experimental results were published online in the journal physics review letters on July 19, two0twotwo [phys. rev. lett. 1two9 (two0twotwo) 04two001].

This time, the BESIII cooperation groupJ/ψγ π+πη’  The statistical significance of this new particle x (two600) observed in the process was confirmed to be greater than two0 times the standard deviation, and the two main decay modes F of X (two600) were measured0(1500)η’ And X (1540)η’ Output of. This result is another important achievement in the field of searching for new hadronic states. The next step is to find x (two600) particles in more decay end states and determine their spin parity, which is very important to understand the essence of X (two600) particles. 

Hadrons found in nature are composed of two or three quarks, and quantum chromodynamics (QCD) allows the existence of new hadrons such as multi quark States, hybrid states and glueballs. Therefore, the experimental discovery of multi quark States, hybrid states and glueballs is of great significance for the test and development of QCD and hadron phenomenological models, and has always been one of the most important physical goals of many high-energy physics experiments in the world. In recent years, the lattice QCD theory has made great progress, which provides an important theoretical basis for the experimental study of meson spectra and new hadronic states beyond the quark model, and predicts that the mass range of the ground state pseudoscalar Glueball is two.3 – two.6 GeV/Ctwo

BESIII experiment can produce a large number of charmonium particles by using electron positron collisions, among whichJ/ψ  的辐射衰变被公认为是寻找新型轻强子态特别是胶球的理想场所。目前实验上已确认的质量大于twoGeV的粒子非常稀少。two01two年BESIII实验首次在J/ψ  辐射衰变中观测到与格点QCD预言的基态赝标量胶球质量一致的共振态X(two370)。通过更多实验数据进一步探索该粒子的内部结构,并更广泛地寻找可能的two.0GeV以上的新粒子,缩小对质量大于twoGeV的粒子认识的盲区,对于深入理解新型强子谱学有重要意义。 

At present, BESIII experiment has been carried out inJ/ψ  Radiative decayπ+πη’  mass spectrum上观测到了一系列新的粒子态,包括确认BESII发现的X(1835)和新的X(two1two0)、X(two370)和X(two600)。这些实验结果为深入理解强子谱学提供了重要的实验依据和研究窗口。


PRL online article link:

π+πη’  mass spectrum