bfys-physics March 2014

bfys-physics@nikhef.nl

9 participants
16 discussions

[Bfys-physics] Bfys Meeting Friday 18 january at 9:30 in N328 and on EVO
by Tjeerd Ketel 09 Jun '14

09 Jun '14

Bfys Meeting Friday 18 january at 9:30 in N328 and on EVO* Paper introduction and discussion: 9:30 "A search for D+(s) to pi+mu+mu- and D+(s) to pi-mu+mu+ decays" by Francesco Dettori http://cds.cern.ch/record/1504407 Veldhoven rehearsals: 10:30 "A new window for new physics in Bs decays to two muons" by Rob Knegjens 11:00 "The Bs meson decay in two muons: a search for rare beauty" by Serena Oggero 11:30 "Measurement of the angle gamma in the unitary triangle in time-dependent Bs to DsK decays at the LHCb experiment" by Manuel Schiller The presentations will be available (protected under lhcb, etc.) on the Nikhef agenda page and comments can be directly mailed to the speakers. Best regards, Tjeerd *)Today Vidyo could not provide the same service as EVO in our meeting room at Nikhef, therefore I decided to book this meeting again on EVO. Universe is the community, as LHCb has been removed. As a test we can open a room in Vidyo on Friday at 12:00. ========================================================= http://agenda.nikhef.nl/conferenceDisplay.py?confId=2361 ========================================================= You have BOOKED a meeting in SeeVogh Research Network (http://research.seevogh.com). Title: Nikhef Description: Bfys Meeting 9:30-12:00 Community: Universe Password: n328 Meeting Access Information: - Meeting URL SeeVogh R.N. http://research.seevogh.com/join?meeting=MsMiMI2u2IDnDe999aDt9s EVO International http://evo.caltech.edu/evoNext/koala.jnlp?meeting=MsMiMI2u2IDnDe999aDt9s - Password: n328 - Phone Bridge ID: 627 7875 Password: 6287 =========================================================

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[Bfys-physics] Comments PAPER-2014-014
by Tjeerd Ketel 01 Apr '14

01 Apr '14

Dear all, Please, have a look at combined comments from Matthias, Jeroen, Gerco, Marcel and myself before Tuesday 20 h. There is a remark about MeV which I did not understand myself (?????? general) and a complicated remark from Gerco which needs our detailed instructions to ask for an improvement of the text in the paper (92-94). Best regards, Tjeerd ----- Doorgestuurd bericht van i93(a)nikhef.nl ----- Datum: Mon, 31 Mar 2014 11:57:36 +0200 Van: Marcel Merk <i93(a)nikhef.nl> Onderwerp: Re: [Bfys-physics] Comments PAPER-2014-014 Aan: Tjeerd Ketel <tjeerd(a)nikhef.nl> Tjeerd, Hartelijk dank voor het verwerken van de commentaren. Mijn comments zitten er al in. groeten, - Marcel On 31 March 2014 11:29, Tjeerd Ketel <tjeerd(a)nikhef.nl> wrote: > Beste Marcel, > Waarschijnlijk wil je nog wat toevoegen. > Stuur het dan vandaag nog rond aan bfys-physics. > Groeten, > Tjeerd > > Comments for LHCB-PAPER-2014-0014: > > General comments: > > - The paper is very difficult to read without having read > the BaBar/Belle publications first. This shows a lack of > interest to who will be reading it. > > - The "Z(4430)-" symbol should be following by a noun > (i.e. Z resonance, Z peak, Z particle, Z parameter). > - Similarly "Belle" should be followed by "collaboration, data or > publication". > - Use the LHCb template symbols style for MeV in line 13, 52 and other. > ??????? > > Detailed comments: > > - Abstract: > - Replace "3 fb-1 of data" by the EB standard expression. See EB rules. > Also used in line 18, > > - Replace "a mass (width) of 4475 (172) MeV" by > "a mass of 4475 MeV and a width of 172 MeV". > > -The abstract should be more concise and several parts can be > removed without missing important points: > Therefore, remove "as also demonstrated using a model-independent > approach", > "and more precise than", "the significance of the Z(4430)- signal is > overwhelming, at least 13.9 sigma, confirming the existence of this state" > (This statement is superfluous as Belle has shown more than 5 sigma), > "in agreement with the 3.4 sigma indication from Belle". > > - Replace "more precise than the previous Belle measurement" by > "more precise than the measurement of the Bell collaboration". > It is not clear if "previous" refers to the last measurement of Belle > or to the one-but-last measurement of Belle. > > - Replace "significance is overwhelming" by > "significance is high". > "Evidence is overwhelming" is also possible. > Also used in line 166. > > - Line 12 or another place: > Mention that natural units (with c=1) are used. > > Line 21-22: > - Replace "one fewer charged pion" by "one charged pion less". > - Replace "to minimize mismodeling" by "to improve modeling". > - Replace "around the Dalitz plot boundary" by > "near the Dalitz plot boundary". > > - Lines 27-32: > How is this efficiency correction supposed to work? > If I integrate over phase space to obtain the normalization, > the best I can hope to achieve is that the average normalization > is good. > This does not (at first glance) seem to help > with efficiency variations over phase space... > Probably, most readers will not get the point without the Babar/Belle > publications... > > - Figure 1: > - Move the figure after its first reference in line 72 > or refer to it earlier, preferable with a description of the background > distribution subtraction and efficiency distribution correction method. > - Describe in the caption the superimposed curve as the distribution we > expect > without resonances in phi'pi. The present text is not suited for in a > caption. > - Make the vertical scale arbitrary by using a scale between 0 and 1. > > - Line 49: > Replace "freedom (ndf) equals Nbin-1 minus the number of ..." by > "freedom, ndf = Nbin - Nvar, with Nvar the number of ..." > Omit -1 here. > > - Line 47: > Replace "confidence level (CL) of the fit" by > "p-value of the fit". > We do not refer to a confidence region here. > Also correct at other places, e.g. in line 62, 64, 77, 120, and 153. > > - Line 48: > How is it possible that the p-value distribution from simulated data > is not consistent with flat? Please, explain better. > This suggests a systematic effect which is apparently NOT simulated. > > - Line 46-50: > Clarify in the text for what reason toy study is done. > And specify exactly which assumption is tested here. > The text suggests only that we did not introduce a bug. > > Figure 2: > Replace "the fit variables (black data points)" by > "(top) the reconstructed invariant mass squared and (bottom) the > angles theta_phi' and phi". > > - Line 83: > Replace "suggests neglecting D-wave decays" by > > "suggests that D-wave decays can be neglected". > > - Line 86: > Replace "p-value" by "$p$-value". > > - Line 93: > Please, clarify: > Do we know what DeltaL distribution we expect? > If not, do we fit the expected shape with a chi^2 probability > distribution (with ndf floating) from toys, and use that to quantify > significances in data fits? > > - Lines 92-94: > "We find that the simulated ?L distribution follows a ?2 PDF with > ndf = 7.50 Â± 0.11 (statistical error)? : > what distribution is EXPECTED? > IS the chi2 distribution chosen more or less phenomenologically? > What is the meaning of ndf in this case? > Is it just some parameter used to parametrise the ?L distribution, > or is it related to something? > In the next sentence the suggestion is made that it is somehow related > to the number of free parameters in the Z- fit. > Also, in what sense does taking ndf=8 result in a CONSERVATIVE result? > Lastly, the distribution in fig. 3 doesn?t look like a chi2 distribution > AT ALL! > > - Line 95: > > You have done toys and concluded that the effective ndf value is 7.5. > Assuming 8, this is 2x the number of free parameters. > But what does that mean? Is this a problem with your model? > Please make this clear in the text. > > Line 105: > Remove "even without considering systematic uncertainties". > This is not how "consistent" should be understood. > > Line 107: > Rewrite "float all K* masses and widths while constraining" and explain > how the masses are constrained. > For example, "by assigning a prior (Gaussian ?) distribution > to them according to the PDG values". > > - Line 117: > Replace "term in Equation (2)" by "term in Eq.(2) of that paper". > > - Figure 3: > If space for explanations is a problem in PRL, then this trivial figure > is a luxury which we could move to the added material. > > - Lines 122+122: > Change the differential "d" in the integrals to roman style (2x). > > - Figure 4: > Add the corresponding mass (or mass2) range of the 6 data points. > > - Figure 5: > - Please give the two Z's different colours and symbols. > - Also add a legend in this plot. > - Change "candidates" to "number of counts" at the axis. > - Replace "data (black points) for m2phi'pi in 1.0<" by > "(black points) reconstructed m2phi'pi for B0->phi'piK+ data > with 1.0 <". > - Replace "veto region" by "excluded". > > - Line 160: > > Write "Figure 5", since it starts a sentence (EB rules). > > - Line 243: > Change "Babar" by "BaBar". > > > > ----- Einde doorgestuurd bericht -----

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[Bfys-physics] Comments PAPER-2014-012
by Jeroen Van Tilburg 31 Mar '14

31 Mar '14

Hi Vasilis, Since I only read about 15% of the B->Jpsi pipi paper, I feel that this paper is not yet in a shape that is presentable to the collaboration. I have put my comments below. Cheers Jeroen General comment about the state of this draft: We feel that the status of this paper is not yet ready for collaboration-wide review. There are too many mistakes in the paper, which make it impossible for institutes to find all of them. This could have been avoided by a more thorough review before. For instance, in large fractions of the text line numbers are missing. This is not acceptable anymore in a CWR. In particular since the problem with the line numbering has been fixed in the LHCb template for more than a year. Not using the LHCb template causes more mistakes, like the captions not being in small font. Also, we think that acknowledgements should have been there as well, even when it is just copied from the template. Further, the paper is very long (almost 30 pages) and mainly aimed at the real experts. We think that a significant reduction of the text would improve the readability of the paper. As it stands, the paper has the quality and size of our ANA notes. One of the main results/motivations for the paper is to search for a contribution from f0(980). While the small improvement in the likelihood is convincing that there is no significant contribution from f0(980), Figure 5 clearly suggests that this something is going on in the region around 980 MeV. Given the width of the f0, there could be some constructive/destructive interference along the mass of the f0. There seems to be a hint of such an effect in the data, since the fit does not perform so well in this region. Did you check this in more detail in the ANA note? Is it possible to construct the phases such that this oscillating behaviour is described? It is worth discussing this in more detail in the paper, since, as it is now, it sticks out for any external reader. Comments on the text and figures: - Abstract: “one-third at 7 TeV center-of-mass energy and the remained at 8 TeV.” It is not clear what is meant here. One third of what. Is this sentence actually needed for this analysis? You can remove it without loss. - Abstract: order the 6 interfering states in mass. - Abstract: “less than |17 degrees|”. The absolute value of 17 is 17. So you should remove the absolute sign ||. Write instead, “the absolute mixing angle between…” Also to be fixed in the conclusions. - l.5: “Cabibbo-suppressed”. Add the dash. - l.5: “over what it is in” -> “compared to” - l.5: “the final state B->JpsiKs”. This is a decay not a final state. - l.6: Remove “Thus”. Not needed. - l.6: Remove “in principle”. This makes the statement very weak. In principle only refers to the statistical precision, which limits a P/T measurement. - l.6: Remove “or limit”. For the same reason as above. - l.7: “the Jpsi pipi decay channel”. This is not a decay channel, but a final state. - l.17: the branching fraction is measured with 3 uncertainties. You either need to say what they are (statistical, systematic, etc), or add them quadratically. - l.42: “where the Jpsi MESON is” - l.44: “by use of either IP requirements or detachment of the Jpsi from the primary vertex”. IP requirements of what? Of the Jpsi or its daughters? Please check. Also add meson after Jpsi. - l.52: remove “four variables”. Every reader is able to add 1+3. - l.53: add colon after “helicity angles” - l. 53-57: place the symbol for the angle always after the word “angle” and not at the end of the (sub)sentence. - l.60-61: remove “plotting” and replace “does” -> “do” - l.69+: Why put the overline suddenly in parentheses here. You have already mentioned in footnote 1 previously that cc in implied. Remove the parentheses. - l.69+: remove “proper” in proper decay time. - Eq.3+4: This should not be written in differential form. This makes it inconstant (and thus wrong) with Eqs. 5-9. In this form the amplitude A should be a differential itself since the full functional form it in there (except for the decay time). However, you do not write it as such in the other equations. - l.70: add a semicolon after “constant” - l.70: “at the decay time, WHICH is itself” - l.75: write “|q/p|” the same way as in the equations before. - Eq.3+4: Since you make the assumptions for q/p and indirect CPV, please simplify these equations from the start. - l.77+: “B0bar MESON” - l.110: write “multivariate selection based on a boosted decision tree (BDT) [21].” - l.164: You constrain the B0 mass to the PDG value for the amplitude analysis. But in l.172 you use the signal fraction from the invariant B mass fit for the angular fit. This looks wrong. You cannot use that number after constraining to the B mass. Maybe you only constrain to the B mass for another fit, but this should be made clear in the text. - Fig. 5 caption: It is not clear who the red points are obtained. Is it from the mass sidebands? From sWeighted background. Explain this in the caption. - Fig. 6: Add “simulation” to the title - l.188: s12 and s13 are already defined. - l.192: Insert (extra) space between m2_hh and as. - Fig. 10: “with the levels on z-axis in arbitrary units” That is already written on the axis. Also the labels are not consistent with the caption. Maybe just say “relative efficiency” in the caption. - l.263: Add comma after however. - l.296: “efficiency-corrected” add dash. - Table 5: This should be MINUS lnL everywhere, right? - Eq.34-37: These are all results, so remove the equation number. - l.348: isopsin -> isospin - Eq. 37: C.L -> CL (without dots). - l.362: add rho(770) in the list of resonances and replace the period by “, where” - l.364: no dash in fit fractions. - l.373: “CP-violating” add dash

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[Bfys-physics] Reminder: Bfys Meeting Friday 28 March at 9:30 in H331
by Tjeerd Ketel 28 Mar '14

28 Mar '14

Dear colleagues, Bfys Meeting Friday 28 March at 9:30 in H331 and Vidyo 9:30 - 9:55 Staff meeting (only permanent staff) 10:00 - 10:50 Introduction and discussion of LHCb-PAPER-2014-012 "Measurement of the resonant and CP components in barB0 to J/psi pi+ pi- decay" by Vasilis Syropoulos Deadline: 01-Apr-2014 Link: http://cds.cern.ch/record/1669578 10:50 - 11:40 Discussion of LHCb-PAPER-2014-014 "The resonant character of the Z(4430)− state" Deadline: 01-Apr-2014 Link: https://cds.cern.ch/record/1670988 The material can be found at http://agenda.nikhef.nl/conferenceDisplay.py?confId=2843 and will be protected by lhcb, etc. Vidyo link in Nikhef Bfys Meeting (at Institutes->Nikhef of Friday 14 March 2014) https://indico.cern.ch/event/307385/ protected by PIN 1328. Best regards, Tjeerd

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[Bfys-physics] Comments PAPER-2014-014
by Jeroen Van Tilburg 28 Mar '14

28 Mar '14

Hi Marcel and Tjeerd, My comments on the Z paper are below. Cheers Jeroen - Z symbol should always be following by a noun (i.e. Z resonance). See e.g. l.148 - Writing “3 fb-1 of data” is deprecated by the EB. See EB rules. Used in abstract and l.18 - Abstract: “more precise than the previous Belle measurement.” What does that a mean? Are there two Belle measurement, and that this measurement is more precise that the first Belle measurement, but less precise than the second Belle measurement? Suggest to write instead: “more precise than the Belle measurement.” - Abstract and l.166: “significance is overwhelming”. Normally, you would say evidence is overwhelming. Significance is high. - Mention in the paper that natural units are used. E.g. in line 12. - l.46-50: Apparently some toy study is done. But for what reason? What is actually tested here. This is not clear from the text. When you have a model and just do some toy studies based on this model, such a test only tells you that you did not introduce a bug somewhere. Please specify exactly which assumption is tested here. - l.47: “confidence level (CL) of the fit”. That is a wrong choice of words. You mean “p-value of the fit” here. Confidence levels are used in the context when quoting confidence regions. Also correct this mistake later on in the paper. E.g. in l. 153. - Throughout the paper, MeV is not using the LHCb template symbols style. e.g. in l.52, l.13, etc. - l.83: “suggests neglecting” -> “suggests that D-wave decays can be neglected.” - l.86: “p-value” -> “$p$-value” - l.95: You have done toys and concluded that the effective ndf value is 7.5. Assuming 8, this is 2x the number of free parameters. But what does that mean? Is this a problem with your model? Please make this clear in the text. - l.117: Write “Eq. (2)” - l.122+122: “d” in the integrals should be in roman style (2x) - Fig. 5: Why do the two Z’s have the same blue color. Please give them different colours. It would also be nice to have a legend in this plot. - l.160: Write “Figure 5”, since it starts a sentence (EB rules). - l.243: “Babar” -> “BaBar”

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[Bfys-physics] Bfys Meeting Friday 28 March at 9:30 in H331
by Tjeerd Ketel 26 Mar '14

26 Mar '14

Dear colleagues, Bfys Meeting Friday 28 March at 9:30 in H331 and Vidyo 9:30 - 9:55 Staff meeting (only permanent staff) 10:00 - 11:00 Introduction and discussion of LHCb-PAPER-2014-012 "Measurement of the resonant and CP components in barB0 to J/psi pi+ pi- decay" by ??? Deadline: 01-Apr-2014 Link: http://cds.cern.ch/record/1669578 The material can be found at http://agenda.nikhef.nl/conferenceDisplay.py?confId=2843 and will be protected by lhcb, etc. Vidyo link in Nikhef Bfys Meeting (at Institutes->Nikhef of Friday 14 March 2014) https://indico.cern.ch/event/307385/ protected by PIN 1328. Best regards, Tjeerd

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[Bfys-physics] Fwd: LHCB-PAPER-2014-007-001-COMMENT-013 (a comment has been made on your comment)
by Gerco Onderwater 21 Mar '14

21 Mar '14

Dear all, Another reply on our comments on the B->Kmumu paper (see below). Please check that your issues have been addressed in the earlier reply (http://cds.cern.ch/record/1667204) and this one and send me additional comments so that I can submit them. As I cannot find any info on when the comments to replies to comments have to be in, please do so **by next wednesday**. I will compile a summary and then resubmit if necessary. Have a nice weekend, Gerco Begin forwarded message: > Resent-From: c.onderwater(a)cern.ch > From: Cds Support <Cds.Support(a)cern.ch> > Subject: LHCB-PAPER-2014-007-001-COMMENT-013 (a comment has been made on your comment) > Date: 21 Mar 2014 14:51:56 GMT+1 > To: Cornelis Onderwater <c.onderwater(a)cern.ch> > > Dear LHCb Colleague, > The comment (LHCB-PAPER-2014-007-001-COMMENT-004) that you made on LHCB-PAPER-2014-007-001 > (entitled: 'Angular analysis of charged and neutral $B \to K \mu^+ \mu^-$ decays') has itself been commented on by Thomas Blake [CERN - PH/ULB] (thomas.blake(a)cern.ch). > > This new comment (LHCB-PAPER-2014-007-001-COMMENT-013) may be seen at > http://cds.cern.ch/record/1670271 > > > Best regards, > The CERN Document Server Server support Team - Gerco Dr. C.J.G. Onderwater Faculty of Mathematics and Natural Sciences Fundamental Interactions and Symmetries Group Nijenborgh 4 NL 9747 AG Groningen Nederland Tel. +31(0)50-3633557 Tel. +31(0)50-3638774 Fax. +31(0)50-3634003

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[Bfys-physics] Looking for a presenter of LHCb-paper-2014-012
by Tjeerd Ketel 21 Mar '14

21 Mar '14

Dear all, We are Looking for the presenter ??? of LHCb-paper-2014-012 for Friday next week. Best regards, Tjeerd

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[Bfys-physics] Fwd: LHCb Tuesday Meeting (18 March 2014) - UNUSUAL ROOM
by Patrick Koppenburg 17 Mar '14

17 Mar '14

Hi all, A warning that the Z- analysis is assigned to us. An important but complicated amplitude fit. Cheers, Patrick -------- Original Message -------- Subject: LHCb Tuesday Meeting (18 March 2014) - UNUSUAL ROOM Date: Mon, 17 Mar 2014 08:02:47 +0100 From: Patrick Koppenburg <Patrick.Koppenburg(a)cern.ch> To: lhcb-general (LHCb General mailing list) <lhcb-general(a)cern.ch> Dear colleagues, Tomorrow there will be a Tuesday meeting in the BE Auditorium 6-2-024 (aka "PS auditorium" or "the green room"). *NOT IN THE FILTRATION PLANT**.* We'll have the approval presentations of two highly anticipated analyses: - ?ACP from semileptonically-tagged D0?hh decays Please note the reading institutes: Warsaw, Genova, Dublin, LPC, Clermont-Ferrand, Syracuse, Zurich - Z(4430)- in B->Psi(2S)Kpi - "the Z analysis" Institutes: Moscow State University, LPNHE Paris, NIKHEF VU, Ferrara, Imperial College London, Ruprecht-Karls-Universität Heidelberg agenda and Vidyo : https://indico.cern.ch/event/237870/ These are two results that will cause a lot of discussion in the near future. I count on your attendance to help improving our results. Cheers, Patrick -- ======================================================================== Patrick Koppenburg LHCb Physics Coordinator Nikhef, Amsterdam & CERN http://www.koppenburg.org/address.html

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[Bfys-physics] Friday's (not) farewell dinner
by Francesco Dettori 14 Mar '14

14 Mar '14

Dear all, (for those of you at Nikhef) as you know I am leaving Nikhef soon, therefore I would like to have a dinner and/or a couple of beers with all of you, to say farewell or better "a nos bidere luèco" (see you soon)! The date will be tomorrow (Friday), while the place will be announced soon. Thanks a lot, Francesco --- Francesco Dettori Nikhef - VU +31 20 592 2230 (Nikhef) +41 22 76 76284 (CERN)

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bfys-physics March 2014