|Speaker:||Takeo Higuchi (IPMU)|
|Title:||The Belle II experiment has been kicked off|
|Date:||Wed, Dec 11, 2019, 15:30 - 17:00|
Despite the great success of the Standard Model (SM) of particle physics, we strongly believe the existence of new physics beyond the SM that can give consistent descriptions for yet-unanswered mysteries in the Universe. In quest of the new physics beyond the SM, we decided to upgrade the electron-positron collider KEKB to SuperKEKB and the large spectrometer Belle to Belle II, which were employed to confirm the effect of matter/anti-matter asymmetry in the neutral B-meson system in 2001 as described by M. Kobayashi and T. Maskawa.
SuperKEKB is designed to deliver B/anti-B meson pairs and tau-lepton pairs at the rate of x40 KEKB, which allows precise search for the new physics in the flavor sector. Belle II is designed to tolerate this higher event rate and harsher beam background environment. We spent more than 10 years since around the end of Belle in 2010 for the accelerator and detector upgrades together with development of new data taking and computing systems and software tools. IPMU was in charge of the production and delivery of the vertex detector to the experiment, which is the essential sub-detector for the new physics at Belle II. After hard works by all the collaborators, we deployed all the sub-detectors in the experiment by November 2018, and through the detector commissioning, we have successfully recorded the collision data on March 11th. We kept data recording after then and have collected 6.5 fb^-1 data already. Excellent detector performance has been demonstrated with the data. I will review the history of the Belle II upgrade, report the recent updates of the experiment, and present the future prospect on the new physics search at Belle II.