Ruoping Zhao (University of Chinese Academy of Sciences): Recent glueball studies at BESIII

Abstract

Recent glueball studies at BESIII

Gluons carry the colour charge of the strong interaction they mediate and therefore interact with one another, so bound states of gluons alone, glueballs, are predicted by quantum chromodynamics. The observation of one would be evidence that a massive particle can be generated by gluon self-interaction alone. None has been unambiguously identified in nearly half a century, in part because mixing with ordinary mesons of the same quantum numbers is possible, so no single measurement is decisive.

Radiative J/ψ decays are gluon-rich and are therefore a favourable place to search; about ten billion J/ψ events, the world’s largest such sample, have been recorded by BESIII. A series of BESIII glueball studies will be presented, in particular the X(2370) measurements, from the 2011 discovery to a recent search for the decay into K*(892)K̄, where no signal is observed.

Such a suppression is expected for a flavour-singlet state, so the absence is itself supporting evidence. Together with the mass, spin-parity and production rate, an interpretation of the X(2370) as a state dominated by the lightest pseudoscalar glueball is supported. Other interpretations currently under discussion will also be addressed.

Zoom information

https://us02web.zoom.us/j/2022111100

(Meeting code: 2022111100 Password: skcm2)