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
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