For the first points at 5.614 GeV we obtained an integrated luminosity of 49 pb^-1. For the rest we will take about 12 pb^-1 at each points with 3 MeV beam energy interval. We expect that about 16 pb^-1 data be taken every day. Now that the machine is stable, it turn out to be a little conservative. Please also note that turn out time of pass2 is about 24 hours.

Around Λ_b pair threshold, the hadronic cross-section is composed of udsc and b quark pairs. The cross-section is about 3 nb. As a comparison we hope to find Λ_b pair cross-section of 50 pb. The hadronic cross section in the plot is obtained from the P1CrystalMonProc.

The number of protons is a good tool for this scan, especially with the requirement of at least one reconstruced lepton (electron or muon) in the event. We have also applied an event shape cut to suppress "continuum" events from udsc quark pairs.

Please note that these are very preliminary plots; the energy dependent efficiency and purity corrections have not yet been done, and the detector performance may be changing during the scan.

Shown in blue dots are for anti-proton only.

The following plot shows the reconstructed Λ_c in pKπ mode. The XP and R2 cuts are not performed to have a clear peak. The data used is the sum of the first 10 scan points. The width from fit is 5.9 ± 1.0 MeV. In comparison the width is about 4 MeV from separate study with CLEO III data.

The following plot shows the sum of reconstructed Λ_c in pKπ, pK_S, and Λπ modes. To extract the number of reconstructed Λ_c, the mass and width are fixed in the fit. Please note that in the left plot no XP or R2 cut is applied.