headshot of Hitoshi Murayama

Research Expertise and Interest

physics, particle physics, the universe, fundamental constituents of matter, Higgs boson, anti-matter, neutrino oscillations, finite value of the cosmological constant, triple coincidence of energy densities

Research Description

Hiroshi Murayama is a professor in the Department of Physics. He is working on particle physics, trying to understand the fundamental constituents of matter and the forces acting among them. The so-called "Standard Model" of particle physics is very successful, and the Higgs boson, which is the "core" of the Standard Model, is supposed to be discovered this decade. However, there are still many problems which remain unanswered even with a future discovery of the Higgs boson. Why are there so many "elementary" particles, repeating three generations which have identical properties except their masses? Why are there three (electromagnetic, weak and strong) forces acting on elementary particles in a seemingly random manner? Why does Higgs boson exist and play such a special role? Why is the Universe so long-lived and has more matter than anti-matter in it?

Recently, two important questions were added to the list. The Universe appears to be accelerating its expansion. Why? The neutrinos are supposed to be completely massless in the Standard Model, but recent indications of neutrino oscillations strongly suggest that they have small but finite masses. How?

These puzzling phenomena must be clues to what is really going on at the most fundamental level in Nature. Using these clues, studying them in detail and ask what is behind is the approach in most of his research.

See current projects

In the News

AAAS Adds Ten New Fellows From UC Berkeley

Ten members of the UC Berkeley community – including nine faculty and one staff member — have been elected American Association for the Advancement of Science (AAAS) fellows, one of the most distinctive honors within the scientific community.

MACHOs are dead. WIMPs are a no-show. Say hello to SIMPs.

The intensive, worldwide search for dark matter has so far failed to find an abundance of dark, massive stars or scads of strange new weakly interacting particles, but a new candidate is slowly gaining followers and observational support.

Theorem unifies superfluids and other weird materials

UC Berkeley physicists Hitoshi Murayama and Haruki Watanabe have proved that counting the number of Nambu-Goldstone bosons in a material reveals the material’s behavior at low temperatures, unifying the description of weird materials such as superfluids, magnets and Bose-Einstein condensates, and allowing the design of new materials with spooky properties.
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