BEEC: An event generator for simulating the Bc meson production at an e+e− collider

It depends on which option one chooses to match PYTHIA when generating the heavy quarkonium events. Typically, for the production of the S-wave quarkonium states, if setting IDPP=2 (unweighted events), then it takes about 2 h on a 2.9 GHz AMD Athlon (tm) II×4 635 Processor machine to generate 105 events; if setting IDPP=3 (weighted events), it takes only ∼16 min to generate 105 events. For the production of the P-wave quarkonium states, the time will be almost one hundred times longer than the case of the S-wave quarkonium.