c c ➝ J/ y g

Quarkonium production in pp at LHC y’ CMS cc ➝ J/y g LHCb ϒ CMS cc1 cc2 cc0 8th Vienna Central European Seminar 25 – 27 Nov. 2011, Vienna, Austria Hermine K. Wöhri, CERN

Quarkonium production puzzles: theory In 1995, CDF observed J/yand y’ directproduction 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 data λθ CDF NRQCD (coloursinglet + colour octet) LO coloursinglet NRQCD factorization: prompt J/yBraaten, Kniehl, Lee, PRD62, 094005 (2000) pT[GeV/c] CDF Run II data: promptJ/y PRL 99, 132001 (2007) NLO colour-singlet: directJ/y Haberzettl, Lansberg, PRL100, 032006 (2008) @1.96 TeV

Quarkonium polarization puzzles: Tevatron experiments _ J/ψ, pp √s = 1.96 TeV CDF Run I CDF Run II 0 . 4 |y| < 0.4 0 . 2 CDF II vs CDF I ➝ not known what caused the change |y| < 0.6 0 . 0 - 0 . 2 Helicity frame PRL 85, 2886 (2000) PRL 99, 132001 (2007) - 0 . 4 - 0 . 6 - 0 . 8 _ 0 1 0 2 0 (1S), pp √s = 1.96 TeV CDF Run II D0 Run II CDF vs D0 ➝ unlikelythatthedifferentrapidity ranges can justifythediscrepancy... |y| < 0.6 |y| < 1.8 Helicity frame Preliminary PRL 101, 182004 (2008) pT [GeV/c]

Exotic quarkonium puzzles: CDF vs Belle X(4140)➝ J/y f with J/y ➝ mm and f ➝ K+K- CDF observed a structure in B+ ➝ (J/y f) K+ decays on the basis of 115 ± 12 B+ (in 6 fb-1) M = 4143.4 +2.9-3.0 ± 0.6 MeV and G = 15.3 +10.4-6.1± 2.5 MeV 19±6 events CDF BELLE could not confirm this state ➝ set an upper limit for s·BR(X): in contradiction to the CDF result [PRL 102 (2009) 242002]and arXiv:1101.6058 ➝ Does the X(4140) really exist???

Quarkonium spectroscopy challenges [similar for charmonium] cb➝ Y(1S)gwith Y(1S) ➝ mm 2P 1P • States identified in analogy to the hydrogen atom: Y(1S), Y(2S), Y(3S), cb0,1,2(1P), cb0,1,2(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 %) CDF

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

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

J/y fraction from B decays vs. pT The beauty feed-down shows a strong pT dependence with saturation for pT > 50 GeV/c The mid-rapidity data points seem to show a similar trend for √s = 1.96 and 7 TeVbut the (very precise) CMS measurements sit systematically higher than those of CDF ATLAS: arXiv:1104.3038 CMS: arXiv:1111.1557 looks good

J/y fraction from B decays vs. pT and rapidity For a given pT, the most mid-rapidity CMS data show a rather different B-fractionthan the most forward LHCb data CMS: arXiv:1111.1557 LHCb: EPJ C71 (2011) 1645 looks good

Prompt J/ypT distributions from LHCb LHCb published very accurate measurements, in 5 rapidity bins, up to pT ~ 15 GeV 5.2 pb-1 LHCb: EPJ C71 (2011) 1645 The shape of the pT distributionscan be reproduced by the function

Prompt J/ypT distributions from LHCb and ATLAS LHCb published very accurate measurements, in 5 rapidity bins, up to pT ~ 15 GeV ATLAS 2.3 pb-1 ATLAS 2.27 pb-1 LHCb 5.2 pb-1 LHCb: EPJ C71 (2011) 1645 ATLAS:arXiv:1104.3038 The shape of the pT distributionscan be reproduced by the function looks good Also ATLAS presented very detailed measurements, extending to higher pT values

Prompt J/ypT shape vs. rapidity <pT2> clearly increases from forward to central rapidity Good agreement between the LHC experiments looks good b = 3.69

Prompt J/y pT distributions from ATLAS, CMS and LHCb • Thanks to the high luminosity at LHC the current prompt J/y spectra extend from pT = 0 already up to 70 GeV/c, spanning 6 orders of magnitude • The ATLAS and recent CMS data agree extremely well over the full pT range ATLAS: arXiv:1104.338 CMS:arXiv:1111.1557

Prompt J/y pT distributions from ATLAS, CMS and LHCb • Thanks to the high luminosity at LHC the current prompt J/y spectra extend from pT = 0 already up to 70 GeV/c, spanning 6 orders of magnitude • The ATLAS and recent CMS data agree extremely well over the full pT range • Good agreement also with the forward ATLAS, CMS and LHCb data looks good LHCb: EPJ C71 (2011) 1645 ATLAS: arXiv:1104.338 CMS:arXiv:1111.1557

Inclusive y’ from LHCb LHCb measured the pT differential inclusive y’ cross section in two decay channels: y’➝ mm y’ ➝ J/y pp 11k in y’ ➝ J/y pp 90k in y’➝ mm LHCb-CONF-2011-026

Prompt y’ from CMS • CMS measured the y’ inclusive, non-prompt and prompt pT differential cross-section • Prompt production cross-section allows for direct comparison with theory (no feed-down) • B-fraction as large for y’ as for J/y: for pT > 20 GeV/c, more than 50% come from B decays arXiv:1111.1557

Prompt y’ to J/ys·BR ratio • The y’ to J/y cross-section ratio increases with pT • CDF measured a systematically higher ratio [PRD80 (2009) 031103 (R)] 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 y’ and J/y cross sections Is this a naïve expectation? [arXiv:1111.1557]

Prompt y’ to J/ys·BR ratio • The y’ to J/y cross-section ratio increases with pT • CDF measured a systematically higher ratio [PRD80 (2009) 031103 (R)] 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 (2s)? The J/y and y’ data were collected in different runs; the luminosities do not cancel… [arXiv:1111.1557] puzzling

Inclusive y’ to J/ys·BR ratio CMS: arXiv:1111.1557 LHCb: EPJ C71 (2011) 1645 (J/y) LHCb-CONF-2011-026 (y’) • Do we also see differences between CMS and LHCb? Note that these are inclusive ratios and that the B-fraction changes (slightly) with rapidity To be redone with prompt ratios… 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

ϒ(1S) pT distributions from CMS and LHCb Also the bottomonium states are now available from more than one LHC experiment looks good CMS: PRD 83 (2011) 112004 LHCb: CMS-CONF-2011-016

ϒ(1S): 〈pT2〉 vs. rapidity • The <pT2> decreases at forward rapidities • It is much larger than for the J/y b = 3.0

Quarkonia 〈pT2〉 vs. rapidity • While the <pT2> is very different from J/y to Y, the average transverse kinetic energies are much closer and show similar trends versus rapidity

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

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

First measurement of the cc2 / cc1 cross-section ratio LHCb reported a first measurement of thecc2 / cc1 cross-section ratio…The measurement disagrees with NLO NRQCD… Even only using 2010 data, LHCb already has amore detailed measurement than CDF  [LHCb-CONF-2011-020] to be further improved with the higher-statistics 2011 data

Also the cb already made a first appearance ! CDF measured large feed-down contributions from the cb states to the Y(1S): cb(1P) ➝ Y(1S) = 27.1 ± 6.9 ± 4.4 % cb(2P) ➝ Y(1S) = 10.5 ± 4.4 ± 1.4 % for Y(1S) with |y| < 0.7 and pT > 8 GeV/c CDF cb(1P) cb(2P) ? LHCb M(cb(1P)) – M(Y(1S)) = 0.44 GeV M(cb(2P)) – M(Y(1S)) = 0.80 GeV [PRL 84 (2000) 2094]

Another look at cc production CMS has a very good mass resolution (better than 10 MeV)thanks to a (very challenging) photon conversion measurement cc ➝ J/y g cc1 cc2 cc0 CMS Tomography of the CMS inner detectorswith photon conversions

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

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 … the fun has started ! and the best is still to come  ➝ for an appetizer on polarization see talk by ValentinKnünz

c c ➝ J/ y g

c c ➝ J/ y g

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