Hi Tjeerd,
My comments on the first paper LHCb-PAPER-2012-035:
Your background model systematic seems very large. it is extracted from differences between a standard fit procedure and s-fit procedure. Is it possible you are overestimating this systematic? Here you have a very small number of background events wrt. the signal, and almost nowhere in the mass plot where you are signal-free. in this case I expect the s-weight procedure to be quite poor, and so show a larger statistical dependence on these few background events. In this case, it could be the difference between the two is then not representative of a systematic bias at all, unless the central values disagree.
[[ Perhaps Gerhard will contradict me here ;) ]]
My comments on the second paper LHCb-PAPER-2012-033:
Figures 2 and 3 are very convincing. Figure 7 is definitely not convincing. Rebinning into a smaller number of bins is advised, such that every bin has at least two events.
Line 197: To evaluate the "significance" of the peak, please fix the mean of the Gaussian to the expected mass difference of 565.1 MeV. Otherwise you suffer from local look-elsewhere effects.
Line 199: I do not understand your comment "variations in the background shapes do not change this conclusion". With such a small number of events of both signal and background, I would expect a reasonable dependence on the chosen shape. Flat, linear, threshold function at zero, polynomial, etc.
Cheers,
Rob
------------------------------------------ Robert Lambert FOM-VU-NIKHEF-Bfys LHCb Email: rob.lambert@cern.ch ------------------------------------------ CERN, 13-1-018 Tel: +41 22 767 4024 Fax: +41 22 766 8109 ------------------------------------------ Nikhef N241 Tel: +31 20 592 2131 Fax: +31 20 592 5155 ------------------------------------------
________________________________________ From: Tjeerd Ketel [tjeerd@nikhef.nl] Sent: 14 September 2012 17:29 To: bfys-physics@nikhef.nl Cc: Rob Lambert Subject: Bfys Meeting Friday 21 September at 9:30 h in N328
Bfys Meeting Friday 21 September at 9:30 h in N328
Please, in advance first read and comment on the second paper.
9:30 Introduction and discussion of LHCb-PAPER-2012-035 by Krystof De Bruyn 10:30 Inventory remarks LHCb-PAPER-2012-033 10:50 End
With the second paper (2012-033) we will quickly go through the comments received, which I will put (or you may put yourself) at the Nikhef Indico: http://agenda.nikhef.nl/contributionDisplay.py/submit?contribId=1&confId... (Please, protect your text with lhcb and the usual passwd)
Draft 1 : LHCb-PAPER-2012-035 Title : Measurement of the time-dependent $CP$ asymmetry in $B^0 \to J/\psi K^0_{\rm S}$ decays Journal : PLB Contact authors : Bruno Souza de Paula, Julian Wishahi Reviewers : Tom Latham (chair), Sajan Easo EB reviewer : Roger Forty Analysis note : ANA-2012-016 Deadline : 26-Sep-2012 e-group : lhcb-paper-2012-035-reviewers Link : http://cdsweb.cern.ch/record/1477749 Twiki : https://twiki.cern.ch/twiki/bin/view/LHCbPhysics/Bd2JpsiKS
Draft 2 : LHCb-PAPER-2012-033 Title : First observations and measurements of the branching fractions for the decays $\bar{B}^0_s \to D_s+ K^- \pi^+\pi^-$ and $\bar{B}^0 \to D_s^+K^+\pi^+\pi^-$ Journal : PRD Contact authors : Steven Blusk Reviewers : Kazu Akiba (chair), Andrea Contu EB reviewer : Pierluigi Campana Analysis note : ANA-2012-076 Deadline : 26-Sep-2012 e-group : lhcb-paper-2012-033-reviewers Link : http://cdsweb.cern.ch/record/1477712 Twiki : https://twiki.cern.ch/twiki/bin/viewauth/LHCbPhysics/B2DsKPiPiPi
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