Central exclusive chi(c) meson production at the Tevatron revisited.

Motivated by the recent experimental observation of exclusive χc events at the Tevatron, we revisit earlier studies of central exclusive scalar χc0 meson production, before generalising the existing formalism to include χc1 and χc2 mesons. Although χc0 production was previously assumed to be dominant, we find that the χc1 and χc2 rates for the experimentally considered χc→J/ψγ→μ+μ−γ decay process are in fact comparable to the χc0 rate. We have developed a new Monte Carlo event generator, SuperCHIC, which models the central exclusive production of the three χc states via this decay chain, and have explored possible ways of distinguishing them, given that their mass differences are not resolvable within the current experimental set-up. Although we find that the severity of current experimental cuts appears to preclude this, the acceptance does not change crucially between the three states and so our conclusions regarding the overall rates remain unchanged. This therefore raises the interesting possibility that exclusive χc1 and χc2 production has already been observed at the Tevatron

Latest Results in Central Exclusive Production: A Summary

Selected new results in central exclusive production (CEP) processes within the pQCD-based Durham model are discussed. Topics covered include the CEP of SM and BSM Higgs-like particles, meson pair CEP and the gap survival probability.Comment: 18 pages, 7 Figures. Based on talk given by V.A. Khoze at `Diffraction 2012' Workshop, Puerto del Carmen, Lanzarote, Spain, Sept. 10-15th, 2012. Some clarification added and discussion of the CEP of the X(3872) and exotic charmonium-like states include

The Phenomenology of Central Exclusive Production at Hadron Colliders.

Central exclusive production (CEP) processes in high-energy hadron–hadron collisions provide an especially clean environment in which to measure the nature and quantum numbers (in particular, the spin and parity) of new resonance states. Encouraged by the broad agreement between experimental measurements and theoretical predictions based on the Durham approach, we perform a detailed phenomenological analysis of γγ and meson pair CEP final states, paying particular attention to the theoretical uncertainties in the predictions, including those from parton distribution functions, higher-order perturbative corrections, and non-perturbative and proton dissociation contributions. We present quantitative cross-section predictions for these CEP final states at the RHIC, Tevatron and LHC colliders

Central exclusive production as a probe of the gluonic component of the eta' and eta mesons

Currently, the long-standing issue concerning the size of the gluonic content of the eta' and eta mesons remains unsettled. With this in mind we consider the central exclusive production (CEP) of eta', eta meson pairs in the perturbative regime, applying the Durham pQCD-based model of CEP and the `hard exclusive' formalism to evaluate the meson production subprocess. We calculate for the first time the relevant parton-level processes gg --> qqbar gg and gg --> gggg, where the final-state gg and qqbar pairs form a pseudoscalar flavour-singlet state. We observe that these amplitudes display some non-trivial and interesting theoretical properties, and we comment on how this can be understood in a MHV framework. Finally, we present a phenomenological study, and show that the cross sections for the CEP of eta', eta meson pairs are strongly sensitive to the size of the gluon content of these mesons. The observation of these processes could therefore provide important and novel insight into this problem.Comment: 31 pages, 9 Figures. Version to appear in EPJC. Discussion clarified and modified, and some numerics update

Standard candle central exclusive processes at the Tevatron and LHC

Central exclusive production (CEP) processes in high-energy proton—(anti)proton collisions offer a very promising framework within which to study both novel aspects of QCD and new physics signals. Among the many interesting processes that can be studied in this way, those involving the production of heavy (c,b) quarkonia and γγ states have sufficiently well understood theoretical properties and sufficiently large cross sections that they can serve as ‘standard candle’ processes with which we can benchmark predictions for new physics CEP at the CERN Large Hadron Collider. Motivated by the broad agreement with theoretical predictions of recent CEP measurements at the Fermilab Tevatron, we perform a detailed quantitative study of heavy quarkonia (χ and η) and γγ production at the Tevatron, RHIC and LHC, paying particular attention to the various uncertainties in the calculations. Our results confirm the rich phenomenology that these production processes offer at present and future high-energy colliders

Central Diffractive Processes at the Tevatron, RHIC and LHC

Central exclusive production (CEP) processes in high-energy hadron collisions offer a very promising framework for studying both novel aspects of QCD and new physics signals. We report on the results of a theoretical study of the CEP of heavy quarkonia (chi and eta) at the Tevatron, RHIC and LHC. These processes provide important information on the physics of bound states and can probe the current ideas and methods of QCD, such as effective field theories and lattice QCD.Comment: Talk given by V.A. Khoze at International Workshop on Diffraction in High-Energy Physics, Otranto (Lecce), Italy, September 10 - 15, 201

Assessment for reaching people with dementia through their senses

SIGLEAvailable from British Library Document Supply Centre-DSC:m00/41600 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Potential applications of an electron cyclotron resonance multicusp plasma source

An electron cyclotron resonance (ECR) multicusp plasmatron has been developed by feeding a multicusp bucket arc chamber with a compact ECR plasma source. This novel source produced large (about 25-cm-diam), uniform (to within {plus minus}10%), dense (>10{sup 11}-cm{sup -3}) plasmas of argon, helium, hydrogen, and oxygen. It has been operated to produce an oxygen plasma for etching 12.7-cm (5-in.) positive photoresist-coated silicon wafers with uniformity within {plus minus}8%. Results and potential applications of this new ECR plasma source for plasma processing of thin films are discussed. 21 refs., 10 figs