bfys-physics March 2017

bfys-physics@nikhef.nl

7 participants
11 discussions

[Bfys-physics] Fwd: RK* analysis approval on Friday (March 31)
by Patrick Koppenburg 29 Mar '17

29 Mar '17

Dear all, There's no bfys meeting on Friday, but this approval, which I seem not to be able to prevent from happening. Please attend. Nikhef will be assigned to reading the paper (unless the EB chair changes it last minute). Cheers, Patrick -------- Forwarded Message -------- Subject: RK* analysis approval on Friday (March 31) Date: Wed, 29 Mar 2017 00:06:03 +0200 From: Vincenzo Vagnoni <vincenzo.vagnoni(a)cern.ch> To: lhcb-general (LHCb General mailing list) <lhcb-general(a)cern.ch> Dear colleagues, on Friday at 11:00 CEST we will have the approval to go to PAPER for the RK* Run-1 analysis. Please see the details below. Note that the approval will be preceded by a presentation on recent findings concerning the measurement on BF(B->K*mumu) with Run-1 data. The CERN room will be reported on the indico agenda in due time. Cheers, Vincenzo https://indico.cern.ch/event/627276/ * 11:00 → 12:35 Approval to go to PAPER: Lepton universality test with B0→K∗0ℓ+ℓ− decays¶ <https://indico.cern.ch/event/627276/#b-248452-approval-to-go-to-pap> Twiki: https://twiki.cern.ch/twiki/bin/viewauth/LHCbPhysics/BdToKstLL o 11:00 Introduction¶ <https://indico.cern.ch/event/627276/#22-introduction>5m Speaker: Vincenzo Vagnoni (CERN and INFN Bologna) o 11:05 News on Run-1 B→K∗μμ differential branching fraction (10'+10')¶ <https://indico.cern.ch/event/627276/#23-news-on-run-1-b-to-kast-mu>20m Speakers: Konstantinos Petridis (University of Bristol (GB)) , Mitesh Patel (Imperial College (GB)) o 11:25 RC report¶ <https://indico.cern.ch/event/627276/#1-rc-report>10m Speakers: Rafael Silva Coutinho (Universitaet Zuerich (CH)) , Vladimir Gligorov (Centre National de la Recherche Scientifique (FR)) o 11:35 Analysis presentation¶ <https://indico.cern.ch/event/627276/#2-analysis-presentation>30m Speakers: Francesco Polci (Centre National de la Recherche Scientifique (FR)) , Jacques Lefrancois (Universite de Paris-Sud 11 (FR)) , Luca Pescatore(Ecole Polytechnique Federale de Lausanne (CH)) , Marie-Helene Schune (Universite de Paris-Sud 11 (FR)) , Martino Borsato (Universidade de Santiago de Compostela (ES)) , Nigel Watson (University of Birmingham (GB)) , Samuel Coquereau (University of Barcelona (ES)) , Simone Bifani (University of Birmingham (GB)) o 12:05 Discussion¶ <https://indico.cern.ch/event/627276/#24-discussion>30m ======================================================= Vincenzo Vagnoni -- European Organisation for Nuclear Research (CERN) Address: EP/LBD 2-1-043, CH-1211 Geneva 23 - Switzerland Phone: +41-(0)22-76-73994 Mobile: +41-75-411-7920 (int. 167920) E-mail: Vincenzo.Vagnoni(a)cern.ch <mailto:Vincenzo.Vagnoni@cern.ch> -- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Bologna Address: via Irnerio 46, I-40126 Bologna - Italy Phone: +39-051-20-91071 Mobile: +39-347-6056920 E-mail: Vincenzo.Vagnoni(a)bo.infn.it <mailto:Vincenzo.Vagnoni@bo.infn.it> =======================================================

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[Bfys-physics] LHCB-CONF-2017-003-001-COMMENT-014 (a comment has been made on your comment)
by Maarten van Veghel 28 Mar '17

28 Mar '17

Dear all, We have received a reply to our comments on the Rk* conf note (http://cds.cern.ch/record/2256336). In my opinion they gave satisfactory replies. Feel free to take a look and see if they are satisfactory for you as well. Cheers, Maarten -------- Forwarded Message -------- Subject: LHCB-CONF-2017-003-001-COMMENT-014 (a comment has been made on your comment) Date: Tue, 21 Mar 2017 09:53:07 +0100 From: CERN Document Server Submission Engine <cds.support(a)cern.ch> To: maarten.vanveghel(a)cern.ch Dear LHCb Colleague, The comment (LHCB-CONF-2017-003-001-COMMENT-007) that you made on LHCB-CONF-2017-003-001 (entitled: 'Lepton universality test with $B^0\to K^{*0} \ell^+ \ell^-$ decays') has itself been commented on by Simone Bifani [CERN - EP/ULB] (simone.bifani(a)cern.ch). This new comment (LHCB-CONF-2017-003-001-COMMENT-014) may be seen at http://cds.cern.ch/record/2256336 Best regards, The CERN Document Server Server support Team

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[Bfys-physics] LHCb Nikhef (bfys) Meeting (24 March 2017)
by Patrick Koppenburg 23 Mar '17

23 Mar '17

Dear all, Tomorrow we have a regular bfys meeting with Laurent as main speaker. https://indico.nikhef.nl/conferenceDisplay.py?confId=677 Please join Patrick -- ======================================================================== Patrick Koppenburg Nikhef, Amsterdam http://www.koppenburg.ch/address.html

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[Bfys-physics] Fwd: referees' report
by Patrick Koppenburg 23 Mar '17

23 Mar '17

Dear all, The Bs->mumu paper got very positive reviews from PRL. For you enjoyment I single out question 5 from Ref A: > 5. The uncertainties on the data points in Figs. 1 and 2 should > probably be mentioned in the captions. How are they calculated? The > uncertainties are asymmetric in Fig. 1 and Fig. 2 (top), and appear to > follow what one would expect from poisson variations of the data. In > that case, given that there are a number of empty bins, shouldn't one > also include upper error bars for the bins where N=0? Then, in Fig. 2 > (bottom), the uncertainties are symmetric, so what do the > uncertainties represent here? Good we invited Ivo. But I think we need a reference for what RooFit actually does. Cheers, Patrick -------- Forwarded Message -------- Subject: referees' report Date: Thu, 23 Mar 2017 11:44:11 +0100 From: Matteo Rama <matteo.rama(a)cern.ch> To: lhcb-paper-2017-001-reviewers <lhcb-paper-2017-001-reviewers(a)cern.ch> Dear RC, all, please find below the replies from the PRL referees. The reports are quite positive. A bit surprisingly, the referee B's report (attached) does not contain any specific question or remark on the paper. Cheers, Matteo -------- Messaggio Inoltrato -------- Oggetto: Your_manuscript LC16542 Aaij Data: Wed, 22 Mar 2017 22:55:57 -0400 Mittente: prl(a)aps.org Rispondi-a: prl(a)aps.org A: matteo.rama(a)pi.infn.it Re: LC16542 Measurement of the B 0 s rightarrow mu + mu - branching fraction and effective lifetime and search for B 0 rightarrow mu + mu - decays by R. Aaij, B. Adeva, M. Adinolfi, et al. Dear Dr. Rama, The above manuscript has been reviewed by our referees. Acceptance of your paper for publication is likely, but we first ask you to consider carefully the appended comments. With your resubmittal, please include a summary of changes made and a brief response to all recommendations and criticisms. Yours sincerely, Robert Garisto Editor Physical Review Letters Email:prl@aps.org http://journals.aps.org/prl/ IMPORTANT: Editorial "Review Changes" http://journals.aps.org/prl/edannounce/PhysRevLett.111.180001 ---------------------------------------------------------------------- Report of Referee A -- LC16542/Aaij ---------------------------------------------------------------------- For more than 20 years, the elusive decay of the Bs meson into a pair of muons has been searched for in earnest by a number of high energy physics experiments. From the beginning, this was seen as an important channel to search for signs of "new physics", be it supersymmetry or something else. Limits, and ultimately measurements, of this channel put strong constraints on theories beyond the standard model. Along with the failure to find new physics in other searches so far, the measurement of the Bs to mu+mu- branching fraction became even more important. Just two years ago, the CMS and LHCb collaborations reported the first observation of this decay in a tour de force analysis of their combined data. With more than 250 citations in just two years, this is one of the most cited publications by the experiments. An observation by a single experiment is now reported for the first time with the present measurement. In addition, an interesting excess in the search for B0 to dimuons is not confirmed in the present paper, and the first measurement of the Bs effective lifetime is shown. Both of these results constrain new physics in a relevant way and are important results on their own. There is no doubt that the paper proposed here is one of the currently most important result by the LHCb experiment, and that the result has wide implications on high energy physics in particular, but that it will also attract attention among non-specialists since the result touches upon some of the most fundamental questions of physics. The paper is well written and at an appropriate level for the subject. There are sections in the middle part which are somewhat difficult to grasp for the non-expert, e.g. regarding the discussion of the various background contributions, but I believe the level of detail is about right, and sufficient references are given for further reading on the technical details. In the end, this is a rather complex measurement of a phenomenon at the 10^-9 level, so one cannot expect all questions to be answered in a short letter. The relevant details however are given, such that the reader can have confidence in the scientific correctness of the results. I only have a few, relatively minor specific comments: 1. This is just about clarity: About the two normalization channels, the text states "The normalization factors combining the two normalization channels are...". For the reader not familiar with such analyses, shouldn't one specify how this "combination" is statistically performed? 2. Regarding the B0 -> mu+mu- limit, the text explains that "an upper limit... is set using the CLs method". There's a vast variety of "methods" that people call "CLs method" (there's "LEP style CLs" and "LHC style CLs" and so on), which for example differ in the way nuisance parameters are treated etc. I assume the authors are not exactly using what has been described in the given reference from 2002, so I think at least half a sentence of additional explanation is necessary. 3. Just after that, the model dependence of the Bs branching fraction measurement is discussed, leading to a non-negligible additional uncertainty. However, this additional uncertainty seems to be neither included in the final result (one could write it as B +- stat. +- exp.syst. +- model dep.), nor is it mentioned in the abstract or summary. Because it is important for the interpretation of the result in other contexts, why not at least mention it in the abstract, summary, or result? 4. The discussion of the lifetime fit uncertainties should be improved a bit. The text states that "The accuracy of the fit... is estimated using a large number of simulated experiments with properties similar to those found in the data". This is fuzzy and unclear - what are "similar properties"? One has to guess that some unknown properties were varied in some unknown way by some unknown amount. It would help to be more explicit here. 5. The uncertainties on the data points in Figs. 1 and 2 should probably be mentioned in the captions. How are they calculated? The uncertainties are asymmetric in Fig. 1 and Fig. 2 (top), and appear to follow what one would expect from poisson variations of the data. In that case, given that there are a number of empty bins, shouldn't one also include upper error bars for the bins where N=0? Then, in Fig. 2 (bottom), the uncertainties are symmetric, so what do the uncertainties represent here? ---------------------------------------------------------------------- Report of Referee B -- LC16542/Aaij ---------------------------------------------------------------------- See Attachment: lc16542_report_1_b.pdf

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[Bfys-physics] REMINDER: Comments on CONF-2017-003, Lepton universality test with $B^0\to K^{*0} \ell^+ \ell^-$ decays
by Maarten van Veghel 17 Mar '17

17 Mar '17

Dear b-vissers, Just a gentle reminder for everyone who has not yet send comments (thank you who did!) of the upcoming deadline (end of today) to pass me the comments for CONF-2017-003 regarding the (really interesting) RK* measurement. Despite that the CONF note will not be published I encourage everyone to read it and comment, the comments will be useful for the upcoming paper and especially physics comments should come as soon as possible. Tomorrow at the bfys meeting I will give a short overview about the analysis (10min). Yours, Maarten "the electron man"

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Re: [Bfys-physics] BsMuMu paper on the arXiv
by Marcel Merk 17 Mar '17

17 Mar '17

Thanks Siim; the congrats also extend to you!! On 17 March 2017 at 13:36, Siim Tolk <siim.tolk(a)cern.ch> wrote: > Hi all, > Good news indeed - we can proudly present it at Moriond, Mick > > This afternoon we will raise a glass at Nikhef to you guys! > > Proost! > Siim > > > > - - - - - - - - - - - - - - - - > Siim Tolk > Herchel Smith Fellow > Cavendish Laboratory > CERN, LHCb > - - - - - - - - - - - - - - - - > > On 17 Mar 2017, at 13:21, Marcel Merk <marcel.merk(a)nikhef.nl> wrote: > > Hoi Mick et al. > Once more congrats with this fantastic achievement and milestone. This > afternoon we will raise a glass at Nikhef to you guys! > Cheers, > - Marcel > > > On 17 March 2017 at 11:25, Mick Mulder <mmulder(a)nikhef.nl> wrote: > >> Hi all, >> >> Our paper on BsMuMu just appeared on the arXiv: >> https://arxiv.org/abs/1703.05747. >> >> These are our results: >> >> 1. *BF(B0s→μ+μ−)=(3.0±0.6+0.3−0.2)×10−9* , where the first uncertainty >> is statistical and the second systematic. This is a 7.8 sigma observation >> and the first single experiment one as a result. >> >> 2. The first measurement of the B0s→μ+μ− effective lifetime, *τ(B0s→μ+μ−)=2.04±0.44±0.05 >> ps*. >> >> 3. No evidence for B0→μ+μ−, so a stringent limit is put at >> *BF(B0→μ+μ−)<3.4×10−10*. >> >> All results are consistent with the Standard Model. >> >> *Thanks to Jennifer, Siim, Flavio and Antonio*, who helped from the >> Nikhef side to obtain this result! >> >> Cheers, >> Mick >> >> _______________________________________________ >> Bfys-physics mailing list >> Bfys-physics(a)nikhef.nl >> https://mailman.nikhef.nl/mailman/listinfo/bfys-physics >> >> > >

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[Bfys-physics] BsMuMu paper on the arXiv
by Mick Mulder 17 Mar '17

17 Mar '17

Hi all, Our paper on BsMuMu just appeared on the arXiv: https://arxiv.org/abs/1703.05747. These are our results: 1. *BF(B0s→μ+μ−)=(3.0±0.6+0.3−0.2)×10−9* , where the first uncertainty is statistical and the second systematic. This is a 7.8 sigma observation and the first single experiment one as a result. 2. The first measurement of the B0s→μ+μ− effective lifetime, *τ(B0s→μ+μ−)=2.04±0.44±0.05 ps*. 3. No evidence for B0→μ+μ−, so a stringent limit is put at *BF(B0→μ+μ−)<3.4×10−10*. All results are consistent with the Standard Model. *Thanks to Jennifer, Siim, Flavio and Antonio*, who helped from the Nikhef side to obtain this result! Cheers, Mick

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[Bfys-physics] LHCb Nikhef (bfys) Meeting (17 March 2017)
by Patrick Koppenburg 16 Mar '17

16 Mar '17

Dear all, We have a bfys meeting tomorrow. https://indico.nikhef.nl/conferenceDisplay.py?confId=577 Maarten will present the RK* result. Although the CONF note has been killed (we now aim for a paper in April), we should still comment on it. Then Sean will sing in honour of St Patrick's name Cheers, Patrick -- ======================================================================== Patrick Koppenburg Nikhef, Amsterdam http://www.koppenburg.ch/address.html

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[Bfys-physics] Tr : Conference report circulation: CONF-2017-003, Lepton universality test with $B^0\to K^{*0} \ell^+ \ell^-$ decays
by Patrick Koppenburg 14 Mar '17

14 Mar '17

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[Bfys-physics] CP violation in C-suppressed charm decay
by Laurent Dufour 08 Mar '17

08 Mar '17

Dear Robert, Via another measurement, it has become accessible for us to measure the CP violation in the Cabibbo suppressed Ds -> K pi pi with an guestimated 0.6% precision, using only Run 2 data thus far. We are now wondering what possible interesting physics there could be here and what we can expect. We would probably give separate numbers for prominent regions of the Dalitz plot, e.g. the K+ rho0 mode. I know there was some interest in these modes back in the days of the delta-acp excitement. I’m very interested in what you think about this mode, so it would be great to get a coffee with you and Marcel some time tomorrow. Would the morning coffee at 10 work for you? Thanks a lot. Cheers, Laurent

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bfys-physics March 2017