bfys-physics May 2014

bfys-physics@nikhef.nl

4 participants
10 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] LHCB-PAPER-2014-022-001-COMMENT-017: Comment Received (fwd)
by Tjeerd Ketel 22 May '14

22 May '14

Dear all, Our response to the answers on our comments about the paper on Z production in p-Pb have been uploaded. Tjeerd ---------- Forwarded message ---------- Date: Thu, 22 May 2014 15:46:31 +0200 From: CERN Document Server Submission Engine <cds.support(a)cern.ch> To: tjeerd(a)nikhef.nl Subject: LHCB-PAPER-2014-022-001-COMMENT-017: Comment Received Dear LHCb Colleague, Your comment: document LHCB-PAPER-2014-022-001-COMMENT-017 has been correctly received. It will be soon added to our Document Server. The comment may be found at this URL: <http://cds.cern.ch/record/1703469> If you detect an error please let us know by sending an email to cds.support(a)cern.ch. Thank you for your comments.

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[Bfys-physics] No bfys meeting this friday
by Marcel Merk 21 May '14

21 May '14

Dear friends, As we have no urgent items on the agenda and the bfys workshop next week, there will be no bfys meeting this friday. Best regards, - Marcel

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[Bfys-physics] LHCB-PAPER-2014-022-001-COMMENT-014
by Tjeerd Ketel 20 May '14

20 May '14

Dear all, We received answers to out comments. I prepared our reaction as attached. A number of them will need some input from Patrick as indicated. Please, make changes before Thursday noon, to return our reaction. Best regards, Tjeerd ---------- Forwarded message ---------- Date: Mon, 19 May 2014 15:39:21 +0200 From: CERN Document Server Submission Engine <cds.support(a)cern.ch> To: tjeerd(a)nikhef.nl Subject: LHCB-PAPER-2014-022-001-COMMENT-014 (a comment has been made on your comment) Dear LHCb Colleague, The comment (LHCB-PAPER-2014-022-001-COMMENT-009) that you made on LHCB-PAPER-2014-022-001 (entitled: 'Observation of $Z$ production in proton-lead collisions at LHCb') has itself been commented on by Christian Urs Elsasser [CERN - PH/ULB] (che(a)physik.uzh.ch). This new comment (LHCB-PAPER-2014-022-001-COMMENT-014) may be seen at http://cds.cern.ch/record/1702676 Best regards, The CERN Document Server Server support Team

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[Bfys-physics] LHCB-PAPER-2014-022-001-COMMENT-009: Comment Received (fwd)
by Tjeerd Ketel 16 May '14

16 May '14

Dear all, The comments by Nikhef are uploaded to CDS. http://cds.cern.ch/record/1702264 Best regards, Tjeerd ---------- Forwarded message ---------- Date: Fri, 16 May 2014 16:35:57 +0200 From: CERN Document Server Submission Engine <cds.support(a)cern.ch> To: tjeerd(a)nikhef.nl Subject: LHCB-PAPER-2014-022-001-COMMENT-009: Comment Received Dear LHCb Colleague, Your comment: document LHCB-PAPER-2014-022-001-COMMENT-009 has been correctly received. It will be soon added to our Document Server. The comment may be found at this URL: http://cds.cern.ch/record/1702264 It may also be viewed from the link 'View the N comments' of the document LHCB-PAPER-2014-022-001-COMMENT-009 (entitled: 'Observation of $Z$ production in proton-lead collisions at LHCb'). If you detect an error please let us know by sending an email to cds.support(a)cern.ch. Thank you for your comments.

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[Bfys-physics] Bfys Meeting Friday 16 May at 9:30 in N328
by Tjeerd Ketel 16 May '14

16 May '14

Dear colleagues, Bfys Meeting Friday 16 May at 9:30 in N328 and Vidyo 9:30 - 9:55 Staff meeting (only permanent staff) Please, send suggestions for master projects to Marcel 10:00 - 10:50 "CPT possibilities in LHCb" by Jeroen Van Tilburg The material can be found at http://agenda.nikhef.nl/conferenceDisplay.py?confId=2864 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 on LHCb-PAPER-2014-022
by Tjeerd Ketel 16 May '14

16 May '14

Dear all, Below I have combined Marcel's and my comments. Please, remove irrelevant remarks, as I got rather irritated by the imprecision of the paper. Tomorrow I will post them on CDS. Tjeerd Comments on LHCb-PAPER-2014-022 (Nikhef) General comments: 1) The beta acceptance factor comes a bit "out of the blue". As a reader once you understand what it is, it is clear. However, it would help to make the definition a bit more explicit in the text. Perhaps already at page 3-4, when the rapidity ranges are shown in figure 2. Also, the y(Z)-prime could be mentioned there. 2) As a result of selecting the common CM-rapidity range - with small overlap - the value of the R_FB changes drastically from 0.94 to 0.094. An alternative could be to extrapolate both measurements to a larger range of 1.5 < y' < 4.5 to reduce the statistical dependence. Of course at the cost of introducing systematic uncertainty due to the extrapolation. 3) A confusion of forward and backward boson production and the forward geometry is introduced in the text. The footnote which defines forward and backward contradicts with the text. Detailed comments by line: Abstract: - Replace "dimuon mass is restricted to 60 to 120 GeV/c2" by "dimuon mass selection is between 60 and 120 GeV/c2". (Two times "to" is not clear.) - Replace "The Z production cross section" by "The partial Z production cross section" or "The fiducial Z production cross section". (It is not clear that the cross section is defined in a certain range.) - Conceptually, the most interesting measurement is the R ratio. However, it is not mentioned in the abstract. Why? Line 2-5: - This is a superfluous first sentence. Remove it or write "The physics program at hadron colliders with nuclear beams include crucial measurements of proton-nucleon collisions". - Reverse first "can ..." and second "can ..." in the second sentence: "Measurements of proton-nucleus collisions are used for the determination of nuclear parton distribution functions (nPFD) and serve as references for nucleus-nucleus collision analyses". Line 10-14: - Replace "xA < 10-2" by "xA < 3x10-2 (Ref.[3])" (or Ref.[1]). - Replace "smaller than 1.0" and "below 1.0" by "smaller than unity". - Replace "caused by the European Muon Collaboration (EMC) effect [2]" by "by the EMC effect [2]". - Remove "while the prediction of RAa is due to the Fermi motion above 1.0 for values of close to xA=1.0 [3]". (No written information is given about values close to xA=1.0 and to Fermi motion in Ref.[3]. There is also no experimental evidence for it.) And remove Ref.[3] for this reason. - Replace "is expected to be" and "is predicted to be" by "is". (This is also stated in this way in line 15.) Line 17: - Remove "only". Line 20-21: - Add "of the kinematic range in these experiments" to "consequence". - Move "for values of Q2 above 10 GeV2" to directly after "nPDFs". (It relates to xA<0.01 and not to xA~1.) - Replace "close to one" by "close to unity". - Replace "10 GeV2" to "100 GeV2". (See supplementary figure). Line 23: - Add "and in the backward direction" before "to xA-values close to unity". - "involve small xA-values" is more precise than "are sensitive to low xA-values". Line 28: - Replace "its forward geometry" by "its acceptance close to the beam line". - Replace "probe xA down to very low values" by - "probe electroweak boson production at very small values of xA". - Replace "points in the forward direction" by "points toward the detector". - Replace "points in the backward direction" by "points away from the detector". Footnote: - The footnote should be placed at line 22. - Replace "'Forward' refers to positive rapidity values defined relative to the direction of the proton beam, 'backward' to the negative rapidity values" by "'Forward' refers to detected muons in the direction of the proton beam and 'backward' refers to detected muons in the opposite direction". (Rapidity makes the footnote unnecessarily longer.) Line 31-33: - Replace "the sensitivity at" by "the parton momentum fraction xA at". - Replace "ranges down to O(10-4) in the forward case and up to one in the backward case at an energy scale Q2=MZ2" by "ranges from 3x10-4 to 3x10-3 in the forward case and from 0.2 to unity in the backward case at the four-momentum square scale of Q2=MZ2". Line 35: - Replace "This paper presents a first measurement" by "In this paper we present a first measurement". Line 38: - Replace "their pseudo rapidities, eta (-ln(tan(theta/2)), which" by "their absolute pseudo rapidities, eta =-ln(tan(theta/2), which". (We compare to positive values.) Line 41: Add "fiducial" to "The fiducial cross section is measured as". Line 43: Add "in the fiducial region" after "epsilon the total efficiency". Line 44: Replace "The results are compared" by "The resulting cross sections are compared". Line 99-102: This is not clearly explained: How can reweighing of a pp candidate (by counting is as 0.1 event for instance) change its track multiplicity to match that of a pA candidate? Or do you mean scaling of the track multiplicity of a pp candidate (by multiplying the track multiplicity by 10 for instance) ? If this only concerns the efficiency determination, then this paragraph (after rephrasing) should move to line 135 and the following suggestion about the caption of figure 3 (below) is irrelevant. Figure 2: - The rapidity scale of the right plot should be negative. - The vertical scale "Candidates/(0.20)" still reads as "Candidates*5.0". We propose "Candidates/bin". Also for Fig.3. - In the caption add ", yZlab," before "in the lab frame" and add ", y'Z," before "in the center-of-mass frame". Also add "Z" to the axis label "y'Z" or we may write "Y^CM_Z" to contrast against y^lab_Z. Same changes in lines 196 and 220 and corresponding equations. Figure 3: - Add information about the "scaling" or "reweighing" of the multiplicity in either the pp or the pPb case with reference to the text. - Move "in (a) ... direction" to after "J/psi candidates". - Take black open circles of black squares for the Z candidates. (In b/w copies there are no colours.) Line 116-117: Remove "cone, radius and R" that refer to a circular geometric constraint: "of the tracks that differ in eta and phi with respect to the muon track by less than sqrt(Delta eta2 and Delta phi2)=0.5". Line 121-123: - Add "above" before "estimations". - Add "rho". - Add "A low background can be expected for the Z signal." (This will explain the high purity.) Line 125: Add "fiducial" to "total fiducial efficiency". Line 135-36: - Also here "track multiplicity reweighted Z candidates" is not clear. - Replace "comes from the GECs, These cuts are based on" by "is related to the global event cuts, based on". Line 136: Replace "as a function of the muon pseudorapidity" by "as a function of both muon pseudorapidities". Line 142: Add a remark about where we loose these candidates from the fiducial region and if this is reasonable choice for the cuts. Maybe be also what a common cut in y^CM-Z would do. Line 190: Why is the choice made for an FB-ratio instead of a FB-asymmetry? It is also confusing as we introduced R(xA,Q2) as a nuclear modification factor, which we do not use here at all. Table 1: Add a final row with total systematic uncertainties. Line 221: - Replace "the results" by "the measured cross sections". (We seem to have a 6.8 sigma Z signal as a result too.) - The statistical 1 sigma uncertainty of RFB is not small compared to unity. So the reader will be puzzled by the statement that no nuclear effect can be concluded. It is explained in line 211, but here only the statistical 1 sigma = +0.104 is given. Line 223-226: - Remove "Nevertheless" and "excellent". Reverse first and second part of the sentence as: "This first observation of Z production in proton-nucleus collisions demonstrate the potential ..." - What differential measurements? Like in figure 2? Then add "as a function of Z rapidity". (Let us be specific.)

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[Bfys-physics] Bfys Meeting Friday 9 May at 9:30 in N328
by Tjeerd Ketel 09 May '14

09 May '14

Dear colleagues, Bfys Meeting Friday 9 May at 9:30 in N328 and Vidyo 9:30 - 9:55 Staff meeting (only permanent staff) 10:00 - 10:50 Discussion on PAPER-2014-022, "Observation of $Z$ production in proton-lead collisions at LHCb" http://cds.cern.ch/record/1697993 Other material can be found at http://agenda.nikhef.nl/conferenceDisplay.py?confId=2863 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] A paper for Nikhef: PAPER-2014-022, Observation of $Z$ production in proton-lead collisions at LHCb (fwd)
by Tjeerd Ketel 06 May '14

06 May '14

Dear all, We have a paper for Nikhef to discuss. I propose to do that next Friday 9 May. A volunteer on short notice is more than welcome to introduce and collect comments on this draft. Please, let me know soon. We then have sufficient time before the deadline of 16 May. Best regards, Tjeerd ---------- Forwarded message ---------- Date: Fri, 2 May 2014 19:06:37 +0000 From: Rolf Oldeman <rudolf.oldeman(a)cern.ch> To: "lhcb-general (LHCb General mailing list)" <lhcb-general(a)cern.ch> Subject: First circulation of publication draft for PAPER-2014-022, Observation of $Z$ production in proton-lead collisions at LHCb Dear Colleagues, A paper is available for your comments: Title : Observation of $Z$ production in proton-lead collisions at LHCb Journal : JHEP Contact authors : Christian Elsasser Reviewers : Silvia Borghi (chair), Johan Blouw EB reviewer : Burkhard Schmidt EB readers : Nigel Watson, Eugeni Grauges Pous Analysis note : ANA-2014-025 Deadline : 16-May-2014 e-group : lhcb-paper-2014-022-reviewers Link : http://cds.cern.ch/record/1697993 Authors : LHCb Twiki : https://twiki.cern.ch/twiki/bin/view/LHCbPhysics/ZInpA The following institutes are requested to make institutional comments: Glasgow, United Kingdom Bari, Italy LAPP, Annecy-Le-Vieux, France Tsinghua University, China EPFL, Lausanne, Switzerland NIKHEF, Netherlands Please send any comments via the CDS system. It is the responsibility of the contact authors to provide replies on all comments made. Subsequent modification to the publication are 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 where final decisions are made. As the last step a short presentation is given to the collaboration and the paper is sent for publication. 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… rd/default.html Regards, Rolf Oldeman

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[Bfys-physics] Vidyo link for today
by Jeroen Van Tilburg 02 May '14

02 May '14

Hi, The Vidyo link for today’s bfys meeting is: http://vidyoportal.cern.ch/flex.html?roomdirect.html&key=7cUnCbw6D3l6 We already connected the room. The meeting starts at 10:00 in N328 (no staf meeting). Groeten Jeroen en Marcel.

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bfys-physics May 2014