A Step Forward to Search for New Physics beyond the Standard Model

Fig.1 Schematic drawing of the SuperKEKB/Belle II facility ©KEK

A new international experimental project, the Belle II experiment using the SuperKEKB electron-positron collider at the KEK laboratory, just started in Japan. A team at Nagoya University led by Prof. Iijima plays leading roles in the project. The researchers aim to search for New Physics beyond the Standard Model.

Particle physicists at Nagoya University are getting excited with the start of a new international experimental project, the Belle II experiment using the SuperKEKB electron-positron collider at the KEK laboratory in Japan. On March 21, 2018, the project entered into a new stage of operation with successful storage of electron beams in the SuperKEKB accelerator main ring.

The SuperKEKB/Belle II project is the successor of the previous KEKB/Belle project, which contributed to establish the Standard Model by measuring the particle-antiparticle asymmetry (known as "CP violation") in B meson decays as predicted by the theory proposed by Prof. Makoto Kobayashi and Prof. Toshihide Maskawa, Nobel laureates in Physics in 2008.

Still, the Standard Model cannot explain the central mysteries of the Universe: Why matter dominates and why anti-matter cannot be found? What is dark matter? etc. Hence physicists believe that New Physics beyond that Standard Model is required.

The SuperKEKB/Belle II project allows us to perform high sensitivity search for New Physics in variety of rare process of "heavy flavor particles", including the b-quark, c-quark and the tau-lepton.

Fig.2 History of peak luminosity (e+/e- colliders) ©KEK

“Since we started to develop the idea of the new experiment, it took more than 15 years to come to this stage. We are very much excited. The project provides young researchers, including graduate students, to find new phenomena and contribute to the progress of fundamental science”, said Prof. Toru Iijima, the director of the center for experimental studies, KMI, and also the leader of the World Research Unit for Heavy Flavor Particle Physics.

The team at Nagoya University led by Prof. Iijima is one of largest group in the collaboration, and plays leading roles in various aspects in the project: construction and operation of a particle detector, called “TOP counter”, newly developed by the group, development of data handling methods using the high performance computers at KMI, and data analysis to find new phenomena.

The first collision of the electrons and positrons is expected in the coming month.