王至勇博士与我及BES合作组的同事们， 利用北京谱议合作组的psi(2S)数据来研究J/psi粒子的不可见衰变于今年发表于《Physics Review Letter》。 最近被《自然中国》选为来自中国大陆和香港的突出科学研究成果。论文的研究亮点已被刊登在网上：

 http://www.naturechina.com.cn/nchina/2008/080604/full/nchina.2008.126.html

 

从我个人来讲，利用psi(2S)-->J/psi pi+pi- 衰变道来寻找J/psi的不可见衰变，这个研究本身的动机是很重要的，但是，由于此衰变的标准模型本底很高，实验上是不可能用来最终确定不可见分支比的。 而我与季晓斌博士合作的《Search for the invisible decays of eta and etaprime mesons in J/psi --> phi eta/etaprime〉倒是实验上本底很干净的, 是未来可行的实验方案。

下面是该评论的英文原文：

 

Particle physics: Include the invisible

by　Tim Reid

Abstract

Experiments at the Beijing Spectrometer may have produced invisible particles that lie outside the Standard Model

Original article citation:

Ablikim, M. et al. Search for the invisible decay of J/psi in psi(2S)--> pi⁺ pi^-J/psi. Phys. Rev. Lett. 100, 192001 (2008).

  Particles made up of a quark and an anti-quark, such as J/psi mesons, might sometimes decay into invisible particles that are not included in the current Standard Model of particle physics. Researchers in the Beijing Spectrometer (BES) collaboration¹ have conducted a search for these invisible states, with promising results.

  The only invisible particle included in the Standard Model at present is the neutrino, and theory predicts that only a tiny fraction of J/psi mesons decay into neutrinos. Therefore if J/psi mesons show a high invisible decay rate, our understanding of particles may require new physics. For example, according to such modified physics theories new 'light dark matter' particles, which have been proposed to explain the strong gamma rays coming from the centre of our Galaxy, could potentially be seen in collision experiments.

  The BES researchers observed 14 million psi(2S) mesons decaying into their lower energy state J/psi, a process that also produces a pion and an anti-pion. In most cases, the J/psi decay produced known particles such as electron–positron pairs. However, in several cases nothing except the two pions were seen by the detector, suggesting an invisible decay. This new data could potentially be used to estimate the properties of new particles, such as bosons, that may mediate the interactions of dark matter.

 The authors of this work are from:
Institute of High Energy Physics, Beijing, China; China Center for Advanced Science Technology (CCAST), Beijing, China; Guangxi Normal University, Guilin, China; Guangxi University, Nanning, China; Henan Normal University, Xinxiang, China; Huazhong Normal University, Wuhan, China; Hunan University, Changsha, China; Jinan University, Jinan, China; Liaoning University Shenyang, China; Nanjing Normal University, Nanjing, China; Nankai University, Tianjin, China; Peking University, Beijing, China; Shandong University, Jinan, China; Sichuan University, Chengdu, China; Tsinghua University, Beijing, China; University of Hawaii, Honolulu, Hawaii, USA; University of Science Technology of China, Hefei, China; Wuhan University, Wuhan, China; Zhejiang University, Hangzhou, China; Institut für Experimentalphysik I, Ruhr-University Bochum, Bochum, Germany.

Reference

1.       Ablikim, M. et al. Search for the invisible decay of J/psi in psi(2S)--> pi⁺ pi^-J/psi . Phys. Rev. Lett. 100, 192001 (2008). | Article | ChemPort |

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