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Hi, > > Decay Nevents BR/BR(totSL) BR/BR(tot)MC breco effect > > B->Dlnu 43365.9 +- 366.797 0.194% 0.186% +4% > B->D*lnu 124123 +- 628.731 0.556% 0.496% +12% > B->D1lnu 12056.5 +- 221.803 0.054% 0.050% +8% > B->D2lnu 7579.53 +- 174.735 0.034% 0.033% +3% > B->D**lnu 36350 +- 384.04 0.163% 0.236% -44% > B->Xclnu(total) 223364 +- 870.031 > > > As you see the effect of the B reconstruction seems to be dependent on > the semileptonicmode on the recoil. > > Two explanations are possible: > > 1) the MC BR are wrong. The BRs have been calcualted at generator level. > 2) breco is dependent on the multiplicity of the recoil it looks like that the effect can be mostly explained by 1). On the DECAY.dec we have B->Xclnu=10.4% and not 11.3% as it has been calculated at generator level. Using 10.4% the table above becomes: Decay BR/BR(totSL) BR/BR(tot)MC breco effect B->Dlnu 0.189 0.201 -6% B->D*lnu 0.558 0.538 +3.7% B->D1lnu 0.054 0.054 0% B->D2lnu 0.034 0.036 -5% B->D**lnu 0.164 0.170 -3.5% B->Xclnu(total) 1 1 on generic MC. Results are very close to the MC prediction. The situation is perfect if we use the cocktail MC Decay BR/BR(totSL) BR/BR(tot)MC breco effect B->Dlnu 0.196 0.201 -2.5% B->D*lnu 0.546 0.538 +1.5% B->D1lnu 0.054 0.054 0% B->D2lnu 0.034 0.036 -5% B->D**lnu 0.169 0.170 -0.5% B->Xclnu(total) 1 1 basically compatible within the stat error (not shown but trust me) Then, with the correct total semileptonic BR, no striking dependence on the recoil decay mode is shown. As a consequence the ratio of the breco efficiency has to be closer to one. Once I put the total semileptonic BR, I get these new values for the ratio of breco efficiencies: B0 ratio(epsbreco) = 0.984 +- 0.049 Bch ratio(epsbreco) = 0.971 +- 0.041 and the weighted average is ratio(epsbreco) = 0.98 +- 0.04 ------------------------------- In this situation,fixing to one and taking the error as systematics is fine. Riccardo is verifying that the total BR corresponds to 10.4% looking at MC truth at generator level. If the total BR will be confirmed let's fix the ratio of breco efficiency to one and calculate the pstarfactor as good as we can and that's it. With the new values of the pstarfactor (depending on the usage of generic only or generic+cocktail) the result will go down by 3-7%. Daniele