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C J/ ϒ c1 c2 c0 Hermine K. Wöhri, CERN CMS LHCb Quarkonium production in pp at LHC 8 th Vienna Central European Seminar 25 – 27 Nov. 2011, Vienna, Austria.

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Presentation on theme: "C J/ ϒ c1 c2 c0 Hermine K. Wöhri, CERN CMS LHCb Quarkonium production in pp at LHC 8 th Vienna Central European Seminar 25 – 27 Nov. 2011, Vienna, Austria."— Presentation transcript:

1 c J/ ϒ c1 c2 c0 Hermine K. Wöhri, CERN CMS LHCb Quarkonium production in pp at LHC 8 th Vienna Central European Seminar 25 – 27 Nov. 2011, Vienna, Austria

2 2 λθλθ CDF Run II data: prompt J/ PRL 99, (2007) NRQCD factorization: prompt J/ Braaten, Kniehl, Lee, PRD62, (2000) NLO colour-singlet: direct J/ Haberzettl, Lansberg, PRL100, (2008) LO colour singlet NRQCD (colour singlet + colour octet) p T [GeV/c] CDF In 1995, CDF observed J/ and direct production cross sections ~50 times larger than expectations from leading-order colour-singlet production NRQCD (including colour-octet terms) described the measured cross section… by freely adjusting long distance matrix elements NLO CSM also able to describe cross sections but no theory able to reproduce the polarization TeV Quarkonium production puzzles: theory

3 3 Quarkonium polarization puzzles: Tevatron experiments CDF Run I CDF Run II Helicity frame CDF II vs CDF I not known what caused the change CDF vs D0 unlikely that the different rapidity ranges can justify the discrepancy... J/ψ, pp s = 1.96 TeV |y| < 0.4 |y| < 0.6 PRL 85, 2886 (2000) PRL 99, (2007) p T [GeV/c] |y| < 1.8 |y| < 0.6 CDF Run II D0 Run II (1S), pp s = 1.96 TeV Helicity frame Preliminary PRL 101, (2008) _ _

4 4 Exotic quarkonium puzzles: CDF vs Belle CDF observed a structure in B + (J/ ) K + decays on the basis of 115 ± 12 B + (in 6 fb -1 ) M = ± 0.6 MeV and = ± 2.5 MeV 19±6 events CDF X(4140) J/ with J/ and K + K - BELLE could not confirm this state set an upper limit for ·BR(X): in contradiction to the CDF result Does the X(4140) really exist??? [PRL 102 (2009) ] and arXiv:

5 5 Quarkonium spectroscopy challenges CDF 1P 2P States identified in analogy to the hydrogen atom: Y(1S), Y(2S), Y(3S), b0,1,2 (1P), b0,1,2 (2P), etc Radially excited states, 1P, 2P, not well measured, but of equal importance for a proper understanding of QCD at work… feed-down into nS states (30 – 40 %) [similar for charmonium] b Y(1S) with Y(1S)

6 6 The LHC achievements seen with a critical eye The next slides give a guided tour through many quarkonium measurements presently available from the LHC experiments Detailed comparisons probe their compatibility or disclose new puzzles, an important check… given the past mutually contradictory results

7 J/ fraction from B decays 7 J/ mesons are copiously produced in B J/ X decays … a background for studies of quarkonium production Prompt and non-prompt J/ mesons are separated through the lifetime dimension [pseudo-proper decay length] l J/ [mm]

8 The beauty feed-down shows a strong p T dependence with saturation for p T > 50 GeV/c The mid-rapidity data points seem to show a similar trend for s = 1.96 and 7 TeV but the (very precise) CMS measurements sit systematically higher than those of CDF J/ fraction from B decays vs. p T 8 ATLAS: arXiv: CMS: arXiv: looks good

9 For a given p T, the most mid-rapidity CMS data show a rather different B-fraction than the most forward LHCb data J/ fraction from B decays vs. p T and rapidity 9 CMS: arXiv: LHCb: EPJ C71 (2011) 1645 looks good

10 For a given p T, the most mid-rapidity CMS data show a rather different B-fraction than the most forward LHCb data J/ fraction from B decays vs. p T and rapidity 10 CMS: arXiv: LHCb: EPJ C71 (2011) 1645 looks good

11 Prompt J/ p T distributions from LHCb 11 LHCb published very accurate measurements, in 5 rapidity bins, up to p T ~ 15 GeV The shape of the p T distributions can be reproduced by the function LHCb: EPJ C71 (2011) pb -1

12 Prompt J/ p T distributions from LHCb and ATLAS 12 Also ATLAS presented very detailed measurements, extending to higher p T values LHCb published very accurate measurements, in 5 rapidity bins, up to p T ~ 15 GeV The shape of the p T distributions can be reproduced by the function LHCb: EPJ C71 (2011) 1645 ATLAS: arXiv: ATLAS 2.27 pb -1 ATLAS 2.3 pb -1 LHCb 5.2 pb -1 looks good

13 Prompt J/ p T shape vs. rapidity 13 clearly increases from forward to central rapidity = 3.69 Good agreement between the LHC experiments looks good

14 Prompt J/ p T distributions from ATLAS, CMS and LHCb ATLAS: arXiv: CMS: arXiv: Thanks to the high luminosity at LHC the current prompt J/ spectra extend from p T = 0 already up to 70 GeV/c, spanning 6 orders of magnitude The ATLAS and recent CMS data agree extremely well over the full p T range 14

15 Prompt J/ p T distributions from ATLAS, CMS and LHCb ATLAS: arXiv: CMS: arXiv: Thanks to the high luminosity at LHC the current prompt J/ spectra extend from p T = 0 already up to 70 GeV/c, spanning 6 orders of magnitude The ATLAS and recent CMS data agree extremely well over the full p T range

16 Prompt J/ p T distributions from ATLAS, CMS and LHCb ATLAS: arXiv: CMS: arXiv: Thanks to the high luminosity at LHC the current prompt J/ spectra extend from p T = 0 already up to 70 GeV/c, spanning 6 orders of magnitude The ATLAS and recent CMS data agree extremely well over the full p T range

17 Prompt J/ p T distributions from ATLAS, CMS and LHCb LHCb: EPJ C71 (2011) 1645 ATLAS: arXiv: CMS: arXiv: Thanks to the high luminosity at LHC the current prompt J/ spectra extend from p T = 0 already up to 70 GeV/c, spanning 6 orders of magnitude The ATLAS and recent CMS data agree extremely well over the full p T range Good agreement also with the forward ATLAS, CMS and LHCb data 17 looks good

18 Prompt J/ p T distributions from ATLAS, CMS and LHCb Thanks to the high luminosity at LHC the current prompt J/ spectra extend from p T = 0 already up to 70 GeV/c, spanning 6 orders of magnitude The ATLAS and recent CMS data agree extremely well over the full p T range Good agreement also with the forward ATLAS, CMS and LHCb data LHCb: EPJ C71 (2011) 1645 ATLAS: arXiv: CMS: arXiv: looks good

19 Inclusive from LHCb J/ LHCb measured the p T differential inclusive cross section in two decay channels: 11k in J/ 90k in LHCb-CONF

20 Prompt from CMS CMS measured the inclusive, non-prompt and prompt p T differential cross-section Prompt production cross-section allows for direct comparison with theory (no feed-down) B-fraction as large for as for J/ : for p T > 20 GeV/c, more than 50% come from B decays arXiv:

21 21 Prompt to J/ ·BR ratio The to J/ cross-section ratio increases with p T CDF measured a systematically higher ratio [PRD80 (2009) (R)] [arXiv: ] It is puzzling to see that CDF measures a significantly higher ratio The higher the collision energy the smaller should be the difference between the and J/ cross sections Is this a naïve expectation?

22 22 Prompt to J/ ·BR ratio The to J/ cross-section ratio increases with p T CDF measured a systematically higher ratio [PRD80 (2009) (R)] [arXiv: ] It is puzzling to see that CDF measures a significantly higher ratio Could it be that the CDF result is too high because of a luminosity bias (2 )? The J/ and data were collected in different runs; the luminosities do not cancel… puzzling

23 23 Inclusive to J/ ·BR ratio Do we also see differences between CMS and LHCb? CMS: arXiv: LHCb: EPJ C71 (2011) 1645 (J/ ) LHCb-CONF ( ) No significant difference between the CMS ratios and the most mid-rapidity LHCb result Deserves a second look on the basis of the higher-statistics 2011 data Note that these are inclusive ratios and that the B-fraction changes (slightly) with rapidity To be redone with prompt ratios…

24 ϒ (1S) p T distributions from CMS and LHCb 24 Also the bottomonium states are now available from more than one LHC experiment CMS: PRD 83 (2011) LHCb: CMS-CONF looks good

25 ϒ (1S): p T 2 vs. rapidity The decreases at forward rapidities It is much larger than for the J/ 25 = 3.0

26 Quarkonia p T 2 vs. rapidity While the is very different from J/ to Y, the average transverse kinetic energies are much closer and show similar trends versus rapidity 26

27 ϒ (1S) rapidity Good compatibility between LHCb and CMS for the d /dy 1S production cross section 27 looks good

28 fdir=0.5 F. Maltoni ϒ (1S) data-theory comparison LHCb CMS 28 The NLO colour singlet model describes the Y(1S) p T differential cross sections, of CMS and of LHCb The NRQCD model is equally successful ! looks good

29 First measurement of the c2 / c1 cross-section ratio 29 to be further improved with the higher-statistics 2011 data [LHCb-CONF ] LHCb reported a first measurement of the c2 / c1 cross-section ratio… The measurement disagrees with NLO NRQCD… Even only using 2010 data, LHCb already has a more detailed measurement than CDF

30 LHCb Also the b already made a first appearance ! CDF measured large feed-down contributions from the b states to the Y(1S): b (1P) Y(1S) = 27.1 ± 6.9 ± 4.4 % b (2P) Y(1S) = 10.5 ± 4.4 ± 1.4 % for Y(1S) with |y| 8 GeV/c [PRL 84 (2000) 2094] M( b (1P)) – M(Y(1S)) = 0.44 GeV M( b (2P)) – M(Y(1S)) = 0.80 GeV b (2P) ? b (1P) 30 CDF

31 Another look at c production CMS has a very good mass resolution (better than 10 MeV) thanks to a (very challenging) photon conversion measurement 31 c0 c1 c2 CMS c J/ Tomography of the CMS inner detectors with photon conversions

32 Prospects for 2011 data analysis All results shown in this presentation were based on the 2010 data Much larger event samples have been acquired in 2011 Good perspectives for many more measurements More potential physics analyses than available people… 32

33 Quarkonium production at the LHC All quarkonium measurements performed so far at the LHC are very consistent among the several experiments good perspectives for major advances in our understanding of quarkonia 33 … the fun has started ! and the best is still to come for an appetizer on polarization see talk by Valentin Knünz


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