Research

Hadron Astrophysics

Establishing the international research institute for High-Energy Hadron Astrophysics led by the neutrino astronomy with the world's most sensitive instruments and massive numerical simulations of cosmic dynamics.

Shigeru Yoshida

Professor of Physics in the Graduate School of Science at Chiba University, and the director of Chiba University's International Center for Hadron Astrophysics.

Ph.D at Tokyo Institute of Technology in 1994, Research associate at University of Utah, Assistant Professor at University of Tokyo before joining Chiba University in 2002. One of the leading scientists in the high energy neutrino astronomy. He has extensively studied connections of neutrinos and ultra-high energy cosmic rays. His major contributions to the discovery of ultra-high energy cosmic neutrinos led to the 2014 Totsuka prize awarded by the Heisei Foundation for Basic Science.

Welcome to the dynamic and energetic universe

What does the word "cosmos" remind you ? You may be thinking of a space walking astronout in the International Space Station. You may be imagining beautiful pictures of stars and galaxies taken by astronomical telescopes. Many of these images would recall a static and full-depth of space with eternity. It is true that our universe certainly has such an aspect. On the other hand, the recent cosmic researches have revealed that universe is actually more extreme and dynamic than you might think. There is an object exposing a transient burst. We found gigantic galaxies blowing particles in a form of jet. These active astronomical objects are not just radiating lights but may also be belting out "matters" - like electrons and nuclei forming our own body - with speed of light, as we have been detecting the earth blasted by bulk of matters with nearly close to the speed of light; They are called "high energy cosmic rays" by physicists. Among them are microscopic particles with energies by billions of billions higher than visible lights. How can our universe produce such energetic radiation of particles? There should be a sort of "cosmic engine" to accelerate particles like protons and nuclei to the speed of light.

Challenging the big mystery of universe with super computers and cosmic neutrino detections.

The mystery of the energetic cosmic radiation has been one of the most important questions regarding our universe, yet remained unresolved for long time. The mission of the International Center of Hadron Astro-Physics (ICEHAP) is to study the cosmic engines blowing out matters with the speed of light. We are conducting two research programs. One is to run "experiments" with super-computers on various hypotheses about the candidate of cosmic engines. This approach is called numerical experiments, rapidly developed recently for inspecting a subject, such as universe, which is inaccessible in a lab. Results of massive computations can be visually displayed as a picture image so that you can intuitively understand what is happening. Our group in ICEHAP is on top front of researchers running the astro-numerical experiments. The another program is to observe our universe with special elementary particles called "neutrinos" to identify powerful astronomical objects working as the cosmic engines. This approach constitute an wing of the "neutrino astronomy", the new way of astronomy established in 21st century. It has been considered as the smoking gun to resolve the long-standing mystery of origin of bulk of the high energy cosmic rays. It was very difficult to realize a neutrino detector instrument to make this possible, but the idea to use the deep glacier ice as "parts" of neutrino telescope has finally brought the breakthrough. The international project at the south pole called IceCube began its full operation. The ICEHAP, Chiba University, is the only Japanese institute of the project, making leading contributions to the scientific discoveries by IceCube such as the first detection of high energy cosmic neutrino signals. Observing the universe with the international collaboration at the extreme environment of south pole makes our research very unique and exciting. It is very the collection of the modern technologies to deploy five thousands of the advanced optical detectors into the 2000 m depth of the polar ice, connecting each other with synchronizing network at precision of one-ten billionth of seconds.

Message to students and young researchers

Academics are not invariant; subjects to change with time. A basic science of universe exploration is not an exception. Evolutions of technologies for observations, detections, and computations keep initiating new windows for surveying our universe. Neutrino astronomy is the most exciting representative of the new windows. A new field like neutrino astronomy fully relies on enthusiasms of junior people like you as there are fewer accumulations of knowledges and experiences from the past. Why don't you join us to work on this newly emerged wonderful science?

Prof. Shigeru Yoshida, standing on the South Pole.

The IceCube Lab at the South Pole.

Photosensors standing by for deployment

The IceCube Drilling House

IceCube Neutrino Observatory

A typical neutrino event seen by the IceCube detector