Results

Figure 14 shows the J/&psi&mu mass distrubutions for the the backgrounds, and the observed events. We observe a clear a signal above background, which is summarized in Table 6. In the 4.0-6.0 GeV/c² mass region we see 60.0 ± 12.6 events above background. This corresponds to a significance of 5.2&sigma .

Figure 14: Left: J/&psi+&mu mass for background estimates. Right: J/&psi+&mu mass for total background and data.

Table 6: Summary of background estimates and data for J/&psi&mu mass windows.

We estimate the relative cross-section times branching ration using the following formula:

We calculate &epsilon_rel, N_Bc and N_B for the two cases: p_T(B)>4.0 GeV/c and p_T(B)>6.0 GeV/c. The results of the calculations for these two cases can be seen in Table 7.

Table 7: Summary of cross-section calculations.

Acknowledgements

We thank the Fermilab staff and the technical staffs of the participating institutions for their vital contributions. This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Culture, Sports, Science and Technology of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; the Swiss National Science Foundation; the A.P. Sloan Foundation; the Bundesministerium fuer Bildung und Forschung, Germany; the Korean Science and Engineering Foundation and the Korean Research Foundation; the Particle Physics and Astronomy Research Council and the Royal Society, UK; the Russian Foundation for Basic Research; the Comision Interministerial de Ciencia y Tecnologia, Spain; and in part by the European Community's Human Potential Programme under contract HPRN-CT-20002, Probe for New Physics.