Cao zhen

I got my Ph. D degree at IHEP in 1994. I worked on theoretic hadron and heavy ion physics for years before joined the HiRes Fly's Eye Collaboration at Utah in 1998. The current research focuses are

1.     Ultra-high energy (UHE) tau neutrino searching above 1015 eV;

2.     Ultra-high energy cosmic ray physics above (1017 eV);

3.     High energy gamma ray astronomy with Tibet ARGO experiment.

I have been establishing a new experiment, the Cosmic Ray Tau Neutrino Telescope (CRTNT), in the IHEP, Beijing, China. Interacting in a mountain body as a huge target, a UHE tau neutrino generates a tau lepton and follows by an air shower by the decay products of the tau escaped from the mountain. An array of 16 fluorescence/Cerenkov light telescopes will be installed behind the mountain to catch those showers. Assuming AGNs are uniformly distributed and expanding with the universe, the event rate has been estimated to be about 10 events per year. They would be the first time for people to catch neutrinos from outside of our galaxy and directly locating the UHE cosmic ray source. Two CRTNT prototype telescopes are constructing in IHEP.

I am conducting an analysis of the HiRes data to measure the cosmic ray energy spectrum. The HiRes experiment has collected more than 8000 events that have been reconstructed by the CRTNT group. A cosmic ray composition in this energy region can be measured by using shower maximum location and other shower development information of those  events. The spectrum and composition above 3 EeV are important for studying the features of the highest energy cosmic rays, such as the GZK cutoff. The CRTNT detector is useful for precisely measure the cosmic ray energy spectrum and composition in the “second knee” (0.1~1 EeV).

Since September 2004, I have joined the ARGO experiment and been elected as the spokesperson of the collaboration. I am devoted to construct the detector and trying to improve the detector for studying cosmic rays above 1 PeV by introducing new facilities such as calorimeter. I am also interested in exploring the possibility of tau neutrino searching using the ARGO detector.

I have published more than 40 papers in particle and astrophysics journals, three of them are published in PRL that marked my research focuses in the past, i.e. sub-structure of quark using high energy cosmic rays (1994); chaotic feature of QCD cascade for quark-gluon-plasma searching in heavy ion collisions (1995); measurement of the cosmic ray composition changing above 1017 eV that, together with the energy spectrum bending, indicates the “second knee” (2000).