News Article - April 8, 2020

First physics results from the upgraded Belle II experiment, the search for a new Z' vector boson "portal" into dark matter, published (Editor's feature/suggested) in "Physical Review Letters"

April 8, 2020

BLOOMINGTON, Ind. -- The first physics results from the upgraded Belle II experiment, the search for a new Z' vector boson "portal" into dark matter, were recently published (Editor's feature/suggested) in Physical Review Letters.

The Belle II experiment is a particle physics experiment at the intensity frontier designed to search for new physics phenomena that cannot be explained by the particles and forces already included in the Standard Model—the world’s reigning (and well-tested) theory of particle physics—while also making precision measurements of known phenomena. The Belle II world-wide collaboration is studying the properties of B mesons (heavy particles containing a bottom quark) and additionally expects significant impact from its exploration of lepton universality violation, new CP violation phases, precision electroweak measurements and dark sector physics.

Belle II is the successor to the Belle experiment, at the SuperKEKB accelerator complex at KEK in Tsukuba, Ibaraki Prefecture, Japan. The Belle II detector was "rolled in" (moved into the collision point of SuperKEKB) in April 2017. Belle II started taking data in early 2018.


The IU Belle II group, currently led by Will Jacobs and including engineers Gerard Visser and Branden Kunkler, and former IU scientific colleagues Anselm Vossen and Yinghui Guan, have helped lead significant US contributions to the new detector development, commissioning and operations as well as scientific interest and support for extracting these important new physics results. In the upcoming years, Belle II plans to obtain 50x the integrated luminosity of the former Belle experiment and many new physics results.

(See also KEK announcement at: