We report a search for narrow resonances that decay into muon pairs in the invariant mass range 6.3-9.0 GeV/c² The data, collected by the CDF II experiment at the Fermilab Tevatron collider, correspond to an integrated luminosity of 630 pb^-1. We set 90% upper credible limits at about 1% on R, the ratio of the production cross section times muonic branching fraction of possible narrow resonances to that of the &upsih(1S) meson.

The results have been approved as of Jul 3rd, 2008.

A more detailed summary of the results can be found here: pdf.

Below are the eps and png versions of all figures for download.

• Figure : Invariant mass spectrum of the selected muon pairs (.eps) (.png)
  
• Figure : fit of the three &upsih peaks (.eps) (.png)
  
• Figure : fit of the search region (background only) with pulls (.eps) (.png)
  
• Figure : fit of the search region (background only) (.eps) (.png)
  
• Figure : 90% upper credible limit on R (.eps) (.png)
  
• Figure : 90% upper credible limit on leptonic width (see text for assumptions) (.eps) (.png)
  
• Figure : 98% upper credible limit on R (.eps) (.png)
  
• Figure : 98% upper credible limit on leptonic width (see text for assumptions) (.eps) (.png)