Hundreds of scientists from all over the world gathered at the Institute of High Energy Physics (IHEP) on July 28-30 to announce the establishment of the International Collaboration of the Jiangmen Underground Neutrino Observatory (JUNO).  

Neutrinos are elementary particles that constitute our matter world. They have many peculiar properties, such as oscillation, which means one type of neutrinos may become another type during the flight. In past years, many new discoveries about neutrinos were announced, including the discovery by reactor experiments of a new type of neutrino oscillation, denoted by the neutrino oscillation parameter θ13.  

The JUNO experiment will study other neutrino-related problems, one of which is the mass hierarchy. This is to say, scientists could find out which type of neutrinos is heavier than others while studying anti-neutrinos produced by nuclear reactors. It can also measure three other neutrino oscillation parameters with an unprecedented precision of less than 1%. This detector can also observe thousands supernova neutrinos if a supernova explodes in our galaxy. Geologists are very excited about the possibility that JUNO can detect thousands of neutrinos from the earth, the so-called geoneutrinos, which can reveal secrets hidden deep in the earth. JUNO is also able to detect a copious number of neutrinos coming from the Sun and other sources.  

"This is a great start. We can imagine that in ten years, we will know our world much better than now and neutrinos will have less secrets than they have now”, said WANG Yifang, IHEP director and the newly-elected spokesperson of the JUNO Collaboration. He also led the Daya Bay Reactor Neutrino Experiment that proved the mixing angle θ13 was different from zero for the first time. “Thanks to the great supports by many worldwide funding agencies, the JUNO experiment can kick off in a timely way and we are running to be the first to measure the neutrino mass hierarchy”, said WANG.  

The JUNO Collaboration consists of more than two hundred scientists from China, Czech, France, Finland, Germany, Italy, Russia, and the US. There are more than 50 collaborating research institutions and universities. “This is truly an international collaboration and we are sure that more institutes will join JUNO in the near future”, said Marcos Dracos of the IPHC/IN2P3 in Strasbourg, France, the newly-elected Chair of the Institutional Board of the Collaboration. 

The JUNO neutrino experiment is located at Kaiping, a small city in the south of China, 200 km from Hong Kong. The 20 kt liquid scintillator detector is located in an underground cavern (to be dug) with a depth of about 700 m from the ground surface. “We are very excited about this experiment and it’s a wonderful and comprehensive physics program”, said Gioacchino Ranucci, director for Technology at the Istituto Nazionale di Fisica Nucleare of Milan, Italy and a newly-appointed deputy spokesperson of the Collaboration. “We are committed to the success of JUNO, since we could bring in our broad expertise in the neutrino investigations which has been carried out for almost two decades in our National Laboratory at Gran Sasso”.  

As the second neutrino experiment hosted in China, JUNO represents a new phase. Its size is huge and some of the required technologies do not exist yet. “This is a very challenging project. It is twenty times larger in scale than the current largest liquid scintillator detector in the world, and its performance will be twice better in energy resolution than the current best one”, said CAO Jun from IHEP, deputy spokesperson of the Collaboration. He is also the current co-spokesperson of the Daya Bay neutrino experiment.  

CONTACT:
WANG Yifang, spokesperson, IHEP, +86-10-88236076, yfwang@ihep.ac.cn 
Gioacchino Ranucci, deputy spokesperson, INFN-Milano, +39-0250317362, gioacchino.ranucci@mi.infn.it 
CAO Jun, deputy spokesperson, IHEP, +86-10-88235808, caoj@ihep.ac.cn
XU Tongzhou, IHEP Public Affairs, +86-10-88235008, xutz@ihep.ac.cn