1 research outputs found
Search for a light exotic particle in J/psi radiative decays
Using a data sample containing 1.06x10^8 psi' events collected with the
BESIII detector at the BEPCII electron-positron collider, we search for a light
exotic particle X in the process psi' -> pi^+ pi^- J/psi, J/psi -> gamma X, X
-> mu^+ mu^-. This light particle X could be a Higgs-like boson A^0, a spin-1 U
boson, or a pseudoscalar sgoldstino particle. In this analysis, we find no
evidence for any mu^+mu^- mass peak between the mass threshold and 3.0 GeV/c^2.
We set 90%-confidence-level upper limits on the product-branching fractions for
J/psi -> gamma A^0, A^0 -> mu^+ mu^- which range from 4x10^{-7} to 2.1x10^{-5},
depending on the mass of A^0, for M(A^0)<3.0 GeV/c^2. Only one event is seen in
the mass region below 255 MeV/c^2 and this has a mu^+mu^- mass of 213.3 MeV/c^2
and the product branching fraction upper limit 5x10^{-7}.Comment: 7 pages, 3 figures, submitted to Physical Review