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Vub measurement using recoil of fully reconstructed Bs

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From:
Kerstin Tackmann <[log in to unmask]>
Date:
18 Jul 2006 15:40:16 -0700 (PDT)Tue, 18 Jul 2006 15:40:16 -0700 (PDT)
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Hi all,

here are the results from the tests concerning the differences in the D**
modeling we talked about this morning. This is done with Concezio's recent
VVF tag and the correction factors are picked up from
corrratiosigpeakmx_newdatadepl.txt. The D** are moved into the "other"
component (-fitdss 1).

Please find the plots here:
http://costard.lbl.gov/~kerstin/vubunf/testdss_Run12fitresults.eps
http://costard.lbl.gov/~kerstin/vubunf/testdss_Run4fitresults.eps

By eye, the fits do look different and here are some numbers:

**Fit on Run 1+2, SP5:
chi2/ndof = 1.64116 (for 7 dof)
ratio other/vcb = 0.296045 / 0.287339 = 1.03 +- 0.17
(with errors:
Vcb comp = 0.287339 +- 0.0183957
Oth comp = 0.296045 +- 0.0442523)

**Fit on Run 4, SP6:
chi2/ndof = 1.90748 (for 7 dof)
ratio other/vcb = 0.117799 / 0.141224 = 0.83 +- 0.13
(with errors:
Vcb comp = 0.141224 +- 0.00785652
Oth comp = 0.117799 +- 0.0174853)

where vcb is D and D*, other is D** and the non-sl bkgd.

The differences might or might not be from the D** - roughly, in SP6 we
would think that the D** should smear down to smaller masses (since
some widths are larger and the minimum masses, with which D** can be
produced can be lower). We subtract less "other" and still the data
spectrum has fewer entries in the bins around 2GeV (and the D** do
smear this far down).


Here is another observation from these fits:

Run 1+2, SP5, numbers of events in the first mX bin:
Data 1' bin = 393.016 +- 26.1089
Vub 1' bin = 1809.31 +- 45.3825
Vcb 1' bin = 482.67 +- 22.7482
Oth 1' bin = 73.6857 +- 9.62637

Run 4, SP6, numbers of events in the first mX bin:
Data 1' bin = 436.967 +- 27.2767
Vub 1' bin = 1528.4 +- 41.7351
Vcb 1' bin = 1327.69 +- 37.7632
Oth 1' bin = 186.534 +- 14.9827

after the mES fit... compare the number of data events (quite similar)
and the number of Vcb events (quite different). As far as I know there is
no SP5/SP6 weight on the generic MC. In the case that we think
efficiencies might be sensitive to the run period, this looks like a
potential problem, doesn't it? And taking Run 3 into account, this looks
even worse. I am confused - I thought we were supposed to have SP5 and SP6
roughly in the ratio of Run1-3 to Run4. And if this is true before any
cuts and bkgd subtraction, it probably should not be vastly different
afterwards.

Cheers,
Kerstin







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