Tevatron-hera colour-octet charmonium anomaly versus higher-order QCD effects

Kniehl, Bernd A.; Krämer, G.

doi:10.1007/s100529800921

Cited by 58 publications

(33 citation statements)

References 38 publications

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“…However, there are other sets of parameterizations for the two color-octet matrix elements O ψ 8 ( 1 S 0 ) and O ψ 8 ( 3 P 0 ) in the literature [12,13]. With these rather small values for the two color-octet matrix elements [12,13], the above predictions of α in the NRQCD FA will be changed. For example, if we follow the values obtained in [13], the two equations of (23) and (24) will be changed to…”

Section: Numerical Resultsmentioning

confidence: 99%

“…With these rather small values for the two color-octet matrix elements [12,13], the above predictions of α in the NRQCD FA will be changed. For example, if we follow the values obtained in [13], the two equations of (23) and (24) will be changed to…”

Section: Numerical Resultsmentioning

confidence: 99%

“…Recently, the photoproduction data from HERA [8,9] put a question about the color-octet predictions for the inelastic photoproduction of J/ψ [10,11] (possible solutions for this problem have been suggested in [12][13][14][15]). Most recently, the CDF collaboration have reported their preliminary measurements on the polarizations of the promptly produced charmonium and bottomonium states [16], which appear not to support the color-octet predictions that the directly produced S-wave quarkonia have transverse polarization at large p T [17,18].…”

Section: Introductionmentioning

confidence: 99%

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Erratum: PolarizedJ/ψproduction in deep inelastic scattering at DESY HERA [Phys. Rev. D 63, 034017 (2001)]

Yuan¹,

Chao²

2002

Phys. Rev. D

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We perform a calculation on the polarization of J/ψ production in deep inelastic scattering in the HERA energy range. For the inclusive production distributions, we find that the color-singlet contributions are consistent with the experimental data in the major region of z (z > 0.4). Only in low z regions, there are some hints of the need of the color-octet contributions to describe the experimental data. For the polarization of J/ψ in DIS processes, we find the parameter α changes with Q 2 . Especially, at higher Q 2 , difference on α between color-singlet and color-octet contributions become more distinctive. In the two regions of lower and larger z, the polarization parameter α have different features. These properties can provide important information on the polarization mechanism for J/ψ production. PACS number(s): 12.40. Nn, 13.85.Ni, 14.40.Gx

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Section: Numerical Resultsmentioning

confidence: 99%

Section: Numerical Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Erratum: PolarizedJ/ψproduction in deep inelastic scattering at DESY HERA [Phys. Rev. D 63, 034017 (2001)]

Yuan¹,

Chao²

2002

Phys. Rev. D

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“…The uncertainties that are shown arise from the uncertainties in the NRQCD color-octet longdistance matrix elements. These matrix elements were obtained through a fit to the Tevatron hadroproduction data that used the NRQCD prediction at LO in α s , augmented by an approximate calculation of some higherorder corrections from multiple-gluon radiation [770].…”

Section: Phenomenology Of the Cross Section Including Nlo Correctionsmentioning

confidence: 99%

Heavy quarkonium: progress, puzzles, and opportunities

Brambilla¹,

Eidelman²,

Heltsley³

et al. 2011

Advances in the Physics of Particles and Nuclei

103

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A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the B-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations at BESIII, the LHC, RHIC, FAIR, the Super Flavor and/or Tau-Charm factories, JLab, the ILC, and beyond. The list of newly-found conventional states expanded to include hc(1P ), χc2(2P ), B + c , and η b (1S). In addition, the unexpected and still-fascinating X(3872) has been joined by * Editors † Section coordinators ‡ Corresponding author: bkh2@cornell.edu more than a dozen other charmonium-and bottomonium-like "XY Z" states that appear to lie outside the quark model. Many of these still need experimental confirmation. The plethora of new states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of cc, bb, and bc bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. Lattice QCD has grown from a tool with computational possibilities to an industrialstrength effort now dependent more on insight and innovation than pure computational power. New effective field theories for the description of quarkonium in different regimes have been developed and brought to a high degree of sophistication, thus enabling precise and solid theoretical predictions. Many expected decays and transitions have either been measured with precision or for the first time, but the confusing patterns of decays, both above and below open-flavor thresholds, endure and have deepened. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hotand cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.

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“…In this paper we have not considered the resolved photoproduction channel which basically contributes at low z region (z ≤ 0.3) [51], where z ¼ P:P h P:q is the energy fraction transferred from the photon to J=ψ in the proton rest frame. In photoproduction, the inelastic variable z can be measured in experiments using the Jacquet-Blondel method [39,40,42].…”

Section: Single-spin Asymmetrymentioning

confidence: 99%

Sivers effect in inelastic J/ψ photoproduction in ep↑ collision in color octet model

Rajesh¹,

Kishore²,

Mukherjee³

2018

Phys. Rev. D

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The prediction of single-spin asymmetry in inelastic photoproduction of J=ψ in ep ↑ collision is presented. At next-to-leading order, the dominating process is photon-gluon fusion, γ þ g → J=ψ þ g for the production of J=ψ in e þ p ↑ → J=ψ þ X, which directly probes the gluon Sivers function.Using the nonrelativistic QCD based color octet model, the color octet states 3 S contribution to J=ψ production is calculated. Sizable asymmetry is estimated as a function of transverse momentum P T and energy fraction z of J=ψ in the range 0 < P T ≤ 1 GeV and 0.3 < z ≤ 0.9. The unpolarized differential cross section of inelastic J=ψ photoproduction is found to be in good agreement with H1 and ZEUS data.

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Tevatron-hera colour-octet charmonium anomaly versus higher-order QCD effects

Cited by 58 publications

References 38 publications

Erratum: PolarizedJ/ψproduction in deep inelastic scattering at DESY HERA [Phys. Rev. D 63, 034017 (2001)]

Erratum: PolarizedJ/ψproduction in deep inelastic scattering at DESY HERA [Phys. Rev. D 63, 034017 (2001)]

Heavy quarkonium: progress, puzzles, and opportunities

Sivers effect in inelastic J/ψ photoproduction in ep↑ collision in color octet model

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