Yes, one more actually: They seem to be lacking a trigger requirement asymmetry (Laurent pointed towards this).
- Any trigger requirement can cause an additional asymmetry. If no trigger requirement is explicitly made, it still means that you are dealing with L0Hadron_TOS or L0Muon_TIS, etc, which are known to have some asymmetry. There seems to be no mention of this, could you please clarify the procedure that you follow in dealing with this?
Cheers, Jacco
On 25 May 2018, at 12:42, Sean Benson sean.benson@nikhef.nl wrote:
Hi all,
I plan to upload later this afternoon, so if you have last minute comments, now is the time.
Best, Sean
Op 24 mei 2018, om 14:38 heeft Jacco de Vries <jdevries@nikhef.nl mailto:jdevries@nikhef.nl> het volgende geschreven:
Hi Sean,
Besides Laurent’s comments, here are some from my side.
l.81 “background due to other two-body B decays”. Where are they used? l.139 “kaon detection asymmetry is determined as a function of the kaon momentum”. We know these to be very dependent on the amount of material (and thus also oneta). Is there a reason a 1D binning was chosen? l.145 “Simulated events are used to obtain …” I assume you use generated signal decays? l.150 “Ap for both decays are found to be equal”. This surprises me, since Fig.2a shows a clear deviation in proton kinematics for low momentum (the bin 10-20 GeV). We know the asymmetry for low momentum to be large, at least a few percent (see e.g. page 19 of https://svnweb.cern.ch/cern/wsvn/lhcbdocs/Users/sstahl/Lambdab/latest/latex/... https://svnweb.cern.ch/cern/wsvn/lhcbdocs/Users/sstahl/Lambdab/latest/latex/main.pdf : here it is 2.5-3% in that bin).
- In addition, you only show the distributions for p > 10 GeV, but there is no mention of such a momentum cut on final state particles. If there is data below 10 GeV, the asymmetry will be even larger.
- Furthermore, as far as I know the Lb production asymmetry analysis (referenced above) is still struggling with finding methods to validate this MC method. How sure are you that your systematic “due to the error on the amount of material in simulation” covers all possible effects, such as using only the p-deuterium Xsection, MC-data differences, etc? Do you have some way of effectively showing that it is "small enough for this analysis”?
l.155 “PID asymmetries are calculated using calibration samples with the aid of simulated events”. Could you give an indication of the relative contribution of MC events to calibration events from data? Do they give compatible results in regions with enough statistics? It would be nice to add a line of verification of this method. l.164 “This turns out to be” —> It is found to be l.175 “The baseline fit model is fitted 250 times […] varying each time the PID efficiencies according to their uncertainties”. This is just another way of assessing the statistical error due to the calibration sample, not a way of determining a systematic error (What would it be a systematic error of?). If the same sample is used to determine the efficiency of the PID cuts, this is then double-counting that statistical error. Seeing as it is (in both the stat. error on the PID eff, and the syst. on the PID asym) the largest source of systematic, this is worrying.
- In addition, we found previously that the choice of binning has a large effect on the resulting PID efficiency / asymmetry. Did you determine the size of such an effect? And what about the dependence of other variables such as nTracks on the PID performance?
Cheers, Jacco
On 24 May 2018, at 13:46, Laurent Dufour <laurent.dufour@cern.ch mailto:laurent.dufour@cern.ch> wrote:
Hi Sean,
These are mine.
l139: Reference 24 is a measurement of the KPi detection asymmetry, not the kaon. Could you mention that you remove the pion contribution using an independent calibration measurement? l143: Reference 24 does not any number for the pion detection asymmetry. How do you get this? l157: This seems worrying. Is there any chance the phase-space coverage is improved in Run 2? Fig.2: The variables in the axis titles have to be italic, and c as well. This holds for more figures. l163: Figure 3 does not show the rapidity distribution of the Lambda b, which is required to draw this conclusion. l163: In Fig. 3 the pseudorapidity distribution does look a bit shifted, compatible with the slightly lower pT distribution. I am surprised this does not lead to any difference in the production asymmetry. Why does this not lead to a difference in trigger asymmetry? Table 1: There is both a “Particle identification” systematic uncertainty, and a “PID asymmetry”. Shouldn’t this be the same thing? Table 1: Why is there an entry for the "kaon or pion detection asymmetry”, but no mention in the paper where this number comes from?
On 21 May 2018, at 15:31, Sean Benson <sean.benson@nikhef.nl mailto:sean.benson@nikhef.nl> wrote:
Hi all,
A reminder to read the paper and provide comments. They would be appreciated by Thursday.
Best, Sean
Op 21 mei 2018, om 15:29 heeft Sean Benson <sean.benson@cern.ch mailto:sean.benson@cern.ch> het volgende geschreven:
Hi all,
A reminder to read the paper and provide comments. They would be appreciated by Thursday.
Best, Sean
Op 16 mei 2018, om 19:08 heeft Patrick Koppenburg <patrick.koppenburg@cern.ch mailto:patrick.koppenburg@cern.ch> het volgende geschreven:
Dear all,
We have a new paper assigned to us. Sean kindly agreed to collect our comments. Please note the circulation deadline is 26/5.
Cheers,
Patrick
-------- Forwarded Message -------- Subject: First circulation of publication draft for PAPER-2018-025, Search for $C!P$ violation in $\Lambda^0_b o pK^-$ and $\Lambda^0_b o p\pi^-$ decays Date: Wed, 16 May 2018 18:28:57 +0200 From: Patrick Koppenburg <patrick.koppenburg@cern.ch mailto:patrick.koppenburg@cern.ch> To: LHCb General mailing list <lhcb-general@cern.ch mailto:lhcb-general@cern.ch> CC: LHCb-PAPER-2018-025-reviewers@cern.ch mailto:LHCb-PAPER-2018-025-reviewers@cern.ch
Dear Colleagues,
A draft paper is available for your comments. Note that due to conference deadlines this draft is on a slightly accelerated schedule.
Team leaders, verify the author list and check for reading obligations. The following institutes are requested to make institutional comments via the CDS link given below:
NIKHEF, Amsterdam, The Netherlands Edinburgh, United Kingdom Roma La Sapienza, Roma, Italy Yandex School of Data Analysis, Moscow, Russia CBPF, Rio de Janeiro, Brazil Santiago de Compostela, Spain
Title : Search for $C!P$ violation in $\Lambda^0_b o pK^-$ and $\Lambda^0_b o p\pi^-$ decays Journal : PLB Contact authors : Fabio Ferrari, Stefano Perazzini Reviewers : Irina Nasteva (chair), Shanzhen Chen EB reviewer : Alberto Correa dos Reis EB readers : Franco Bedeschi, Mike Williams Analysis note : ANA-2018-002 Deadline : 26-May-2018 e-group : lhcb-paper-2018-025-reviewers CDS link : https://cds.cern.ch/record/2318506 https://cds.cern.ch/record/2318506
Authors : LHCb Twiki : https://twiki.cern.ch/twiki/bin/view/LHCbPhysics/Lb2phCPV
It is the responsibility of the contact authors to provide replies to all comments made. Subsequent modifications to the draft will be made in consultation with the reviewers and during the EB reading. Following this, there will be a final meeting of the editorial board, with contact authors and reviewers present, when final decisions will be made. As the last step, the collaboration will be given a final opportunity to comment during a 'silent approval' period.
You can find all paper and conference report drafts open for comments via the EB web-page, by clicking on Current Drafts:
http://lhcb.web.cern.ch/lhcb/lhcb_page/collaboration/organization/editorial_...
Best regards, Patrick
--
Patrick Koppenburg Nikhef, Amsterdam
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