1 V.A. Khoze ( IPPP, Durham ) Central exclusive production of heavy quarkonia and charmonium-like states (selected topics ) X
2 Introduction (why we are interested in CEP processes?) Standard Candle CEP reactions. CEP as a way to study old and new heavy resonances Towards the Full Acceptance Detector at the LHC (bj-1992). Summary and Outlook. With a bit of personal flavour
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4 (a lot of attention) (KMR-2000)
5 Forcing two camels to go through the eye of a needle High price to pay for such a clean exclusive environment : σ H (CEP) ~ σ H ( inclus. ) R apidity Gaps should survive hostile hadronic radiation damages and ‘ partonic pile-up ‘ symbolically W = S² T² Colour charges of the ‘digluon dipole’ are screened only at r d ≥ 1/ (Qt) ch GAP Keepers (Survival Factors), protecting RG against: the debris of QCD radiation with 1/Qt≥ ≥ 1/M (T) soft rescattering effects (necessitated by unitariy) (S) H P P How would you explain this to your (grand) children ?
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9 All 3 measurements are all in good agreement (factor “few”) with the Durham group predictions. * * * Prpospects ! (more coming soon ) Tevatron observations: CDF and D0 each have a few exclusive JJ events > 100 GeV 80
10 Too good to be true ?! Phys.Rev.Lett.102:242001,
11 (A. Alekseev-1958-positronium) KMR-01 The effects of non-zero (especially for 2 + ). …and especially without proton detectors!
12 2 First ‘exclusive’ events now being seen at LHCb. Results suggestive of a sizeable contribution. 1 : 0.6 : 0.22
13 Spin-parity Analyzer
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15 (in a good agreement with the Durham expectations)
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17 PT expectations if no proton tagging Violation of -momentum transfer through the ‘digluon Pomeron’ In the low mass region: is small. Non-relativistic effects for spin 2. Non-PT contribution ( for spin 1, still ~ ). Fluctuations in hadronization KKMRZ Spin-2 quarkonium suppression is easier to violate! for CEP (KMRS-04) ppY+X+Z
18 Very topical for forthcoming measurements with tagged forward protons. KKMR-03 Hopefully, LHCb one day if/when RPs are installed.
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24 and light (CMS, Totem+CMS- soon to come)
25 (Currently no complete theoretical description of onium properties.) (BABAR (2008)) (spins- still unconfirmed) The heaviest and most compact quark-antiquark bound state in nature P-wave Bottomonia
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28 Zoo of charmonium –like XYZ states
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30 “Charmonium production & decay”, 6-8 March 2013, LAL, Orsay
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33 Good Luck to LHCb
34 Towards Full Acceptance Detector (bj- 1992) (FSC at least a good foot in the door) IS THERE A WAY OUT ? Yes, an addition of Forward Shower Counters around beam pipes- low PU runs first results of combined CMS+ TOTEM measurements with the FSCs on (see showers from particles with | | = 7-9) ( Alice is installing such counters, ongoing studies for LHCb)
35 Published in JINST-2009 (Installed in 2011 at the CMS)
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37 LHCb Excellent particle ID (pion/Kaon separation), vertex and proper time resolution exotic states…. Potentially rich program of CDP studies with the LHCb JINST 4:P11019,2009.
38 Disclaimer : up to the experts to deliver a verdict JINST 4:P11019,2009.
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40 An installation of the FSCs and RPs at the LHCb could strongly enhance physics potential for the CEP measurements. Currently active studies are in progress, both on the experimental and theory sides.
41 We are looking forward to new exciting adventures in Exclusiveland
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48 UNCERTAINTIES Known Unknowns Unknown Unknowns N(N)LO- radiative effects (K-factors etc..) ‘…possible inadequancy of PT theory in s …’ R.Barbieri et al-1980 ‘ ‘Right’ choice of gluon densities, in particular at so low scales as in the case ( potentiality of a factor of ~3 rise for the H-case ). Complete model for calculation of enhanced absorption. Gluons at so low scales, surprises are not excluded at all. Non- pQCD effects in the meson characteristics. Currently no complete description of heavy quarkonium characteristics. ‘ Two gluon width does not tell the whole story.’ Could be Factor of 5 up or down
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