bfys-physics

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520 discussions

[Bfys-physics] Friday beer from 17-18 h in N256
by Tjeerd Ketel 10 May '12

10 May '12

Dear all, To celebrate with you my "official retirement" and to exhibit the "VELO artwork" that I received last week at the dinner with a few of you and my family I invite you at the "regular beer meeting" in N256 on Friday. Tjeerd

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[Bfys-physics] Bfys Meeting at Friday 11 May at 9:30 h in H331
by Tjeerd Ketel 08 May '12

08 May '12

Bfys Meeting at Friday 11 May at 9:30 h in H331 Dear Colleagues, I provisional booked a Bfys Meeting in H331 and EVO for Friday 11 May from 9:30 - 10:45 h - to be confirmed - to discuss the paper: Title : Measurement of the branching fractions of charmless charged two-body decays of bottom hadrons Journal : JHEP Contact authors: Vincenzo Vagnoni Referees : Dave Websdale (chair), Andrew Powell, Peter Clarke (EB) Institutes : Glasgow, United Kingdom. Bari, Italy NSC KIPT, Kharkiv, Ukraine. CPPM, Marseille, France EPFL, Lausanne, Switzerland. NIKHEF, Netherlands Analysis note : ANA-2011-019 Deadline : 21-May-2012 e-group : lhcb-paper-2012-002-reviewers Link : https://cdsweb.cern.ch/record/1446186 Twiki : https://twiki.cern.ch/twiki/bin/viewauth/LHCbPhysics/B2hhBR2011 I am looking for a volunteer to introduce this analysis on short notice. Please, let me know!! The latest option for review would be Wednesday 16 May, as 17-18 May are holidays. Best regards, Tjeerd

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[Bfys-physics] upload of the comments on LHCb-paper-2012-005
by Tjeerd Ketel 01 Apr '12

01 Apr '12

Dear all, I just uploaded our comments about Bs->J/psi pi+pi- at https://cdsweb.cern.ch/record/1432244 Best regards, Tjeerd

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[Bfys-physics] Bfys meeting on Friday 23 March in H135 and EVO
by Tjeerd Ketel 28 Mar '12

28 Mar '12

Bfys Meeting at Friday 23 March 9:30 h in H135 and EVO Dear Colleagues, I have booked a Bfys Meeting in H135 and EVO for Friday 23 March from 9:30 to 12:00 h: 9:30 h: "Introduction and review of the paper on Bs->J/psi pi+pi-" by Kristof de Bruyn see https://cdsweb.cern.ch/record/1432244 10:30 h: Break 11:00 h: "Introduction and review of the paper on Ds+ - Ds- asymmetry" by Marcel Merk see https://cdsweb.cern.ch/record/1432243 These papers are assigned to Nikhef for comments. With these introductions we hope to stimulate you to read the drafts and to send your comments before Tuesday next week. We will collect the comments and circulate them before posting them before the deadline Thursday 29 March. Best regards, Tjeerd =================================================================== Slides will be available at the Nikhef Calendar: http://agenda.nikhef.nl/conferenceDisplay.py?confId=1823 =================================================================== You have BOOKED a meeting in EVO (http://evo.caltech.edu). Title: Nikhef Description: Bfys Meeting 9:30-12:00 h Community: LHCb Password: n328 Meeting Access Information: - Meeting URL http://evo.caltech.edu/evoNext/koala.jnlp?meeting=MeMMMu2v2DDDDl9I98Dv9e - Password: n328 - Phone Bridge ID: 496 5237 Password: 6287 EVO Phone Bridge Telephone Numbers: --------------- - Switzerland (CERN, Geneva) +41 22 76 71400 - Netherlands (Nikhef, Amsterdam) +31 20 7165293 Dial '2' at the prompt - Skype (tm) (World-wide) evo.phone See: http://evo.caltech.edu/evoGate/Documentation/extclient/skype/skype.html ===================================================================

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[Bfys-physics] new video for the master PP&AP
by Tjeerd Ketel 27 Mar '12

27 Mar '12

Dear all, I just got the link to a new video about the master Particle Physics and Astroparticle Physics in Amterdam. Enjoy! Tjeerd http://www.youtube.com/watch?v=x5nXOxUpb0g&feature=youtu.be

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[Bfys-physics] Reminder location Vava
by Marcel Merk 26 Mar '12

26 Mar '12

Der bfys friends, Let me remind you that that the seminar of Vava takes place at room H220 at 14h00. Cheers, - Marcel

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[Bfys-physics] Seminar Vava today
by Marcel Merk 26 Mar '12

26 Mar '12

Dear friends, Today (Monday 26 March) Vava (Vladimir Gligorov) is at Nikhef and will give a seminar at 14h00 in H220 on the physics of Bs->Ds+Ds- decays. Since many of us are at CERN, I hope that the people at Nikhef can come to the presentation. Groet, - Marcel

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[Bfys-physics] General comments to Ds+ - Ds- asymmetry paper
by Marcel Merk 23 Mar '12

23 Mar '12

Here are my general comments on the Ds+ - Ds- asymmetry paper: 1) The measurement of A_p assumes that the only source of asymmetry is the efficiency to detect the pion. The fact that the kaon momenta are not identical and that there are momentum dependent material effects is not addressed. We think that this issue should be addressed by a full MC simulation. A demonstration that a MC input asymmetry would be correctly reconstructed would solve this. 2) A specific difference between magnet up and magnet down data is that there is a different crossing angle of the colliding proton bunches. This could have a potential effect on the magnet up and magnet down asymmetry measurement. This is however not addressed in the paper. 3) The main subject of the paper is the determination of the pion efficiency. The pion detection efficiency asymmetry is derived in a beautiful way from the D* decays. However, the absolute pion detection efficiency, as can be derived from table 1 is about 45%. Clearly, this is not a pion detection efficiency for a particle inside the LHCb acceptance, but includes analysis specific cuts. Although the absolute value of the detection efficiency is specific to this analysis, it is assumed that the asymmetry is universal. Also here, we think that the argument would be more solid if one could correctly reconstruct an input asymmetry in a MC simulation. For this a signal-only MC would be sufficient. 4) The efficiency ratio for a given magnet field orientation has a strong azimuthal dependency. In the pi+/pi- average the dependency cancels within statistics (Fig 8). This implies that a positive pion in, say, magnet up configuration should have an identical azimuthal detection efficiency distribution as compared to a negative pion in magnet down configuration. Could this point perhaps be made more explicit? 5) To determine the efficiency per momentum bin the inferred momentum of the missing pion is required, as stated in the paper. However this momentum has a large uncertainty. How is the binning done? Or, more specifically, how large is the effect of applying the "unfolding matrix" (line 125)? 6) We miss text to justify the PDF's (appendices) used to describe the mass shapes. In particular the use of a Bifurcated Student t-function in connection with a mass shape is unexpected. Please motivate it. Also the shape of the WS mass distribution in K2pi distribution has a "dip" that is modelled with a Gaussian with negative fraction f_1. What could be the physics behind such a distribution? Cheers, - marcel

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[Bfys-physics] Comments to Ds+ - Ds- production asymmetry paper
by Marcel Merk 23 Mar '12

23 Mar '12

Dear colleagues, I'm collecting comments on the Ds+ - Ds- production asymmetry paper LHCb-PAPER-2012-009. Please send me any comments you might have before Tuesday 27/3. Cheers, - Marcel

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[Bfys-physics] Fwd: [Theory-wide] Nikhef theory seminar -- moved to N328
by Robert Fleischer 21 Mar '12

21 Mar '12

FYI Begin forwarded message: > From: Damien George <dpgeorge(a)nikhef.nl> > Date: March 21, 2012 4:18:12 PM GMT+01:00 > To: theory-wide(a)nikhef.nl, Marcel Merk <i93(a)nikhef.nl>, Eddy Jans <eddy(a)nikhef.nl>, Niels Tuning <h71(a)nikhef.nl> > Subject: [Theory-wide] Nikhef theory seminar -- moved to N328 > > Dear all, > > The theory seminar for tomorrow (Thur 22nd) has been moved to room N328 so > that we can fit more people. > > Hope to see you there. > > Regards, > Damien George and Mert Aybat. > > ---- > > Date/place: Thursday 22nd March, 2pm, N328 > Speaker: Alexander Lenz (CERN) > Title: B mixing - What did we learn from LHCb in 2011? > > I will review the current status of standard model predictions for > B-mixing in the light of the most recent results of LHCb and TeVatron > presented at Moriond 2012. Conseuqences for new physics searches will > also be discussed. > _______________________________________________ > Theory-wide mailing list > Theory-wide(a)nikhef.nl > https://mailman.nikhef.nl/mailman/listinfo/theory-wide

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