BRTW Fit on D0+D0bar Inv. Mass Plots from 1 st Production & Effective Signal Calculation 1 st December 2010

MassD0 = , sigma = 20MeV and Reject point at 3 sigma S/N ~ (raw yield, from Yuri’s calculation) Significance (s/√(s+b)) ~

With MassD0 = , sigma = 20MeV and Reject point at 4 sigma S/N ~ (raw yield, from Yuri’s calculation) Significance (s/√(s+b)) ~

With MassD0 = , sigma = 20MeV and Reject point at 5 sigma S/N ~ (raw yield, from Yuri’s calculation) Significance (s/√(s+b)) ~

With MassD0 = , sigma = 20MeV and Reject point at 5 sigma but with increased fit range (1.7,2.1) S/N ~ (raw yield, from Yuri’s calculation) Significance (s/√(s+b)) ~

With MassD0 = , sigma = 15.5MeV and Reject point at 5 sigma S/N ~ (raw yield, from Yuri’s calculation) Significance (s/√(s+b)) ~

Sigma of the pure D0 sample (power law pT distribution) Pure D0 hijing sample gives a sigma of 15.5MeV

Summary The reject point used in BRTW macro was varied to see the effect When the reject point is increased to 4 or 5 sigma we get a better chi^2/ndf Also looked at the sigma of D0 signal from Simulation and it is about 15.5MeV A better fit is obtained by increasing the sigma from the default value 10MeV used in the fit macro to 20MeV  Attempted to calculate the effective signal S/√(S+B) by counting the number of entries under the signal and background curves.  Best value of Effective Signal got is 3.47 corresponding to a raw yield of  Need to look at the sigma of D0bar and D0+D0bar from simulation.  Need to check if the calculation of effective signal is right.