Fragmentation, nonrelativistic QCD, and NNLO factorization analysis in heavy quarkonium production

Nayak, Gouranga C.; Qiu, Jian‐Wei; Sterman, George

doi:10.1103/physrevd.72.114012

Cited by 173 publications

(238 citation statements)

References 71 publications

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“…Consequently, at large p/m Q , higher orders in the perturbation expansion may be more important than lower orders. Therefore, it may be useful to organize the production cross section in powers of p/m Q before expanding the short-distance coefficients in powers of α s [629][630][631].…”

Section: The Nrqcd Factorization Approachmentioning

confidence: 99%

“…In the fragmentation-function approach to factorization for inclusive quarkonium production [629][630][631], one writes the production cross section in terms of convolutions of parton production cross sections with light-cone fragmentation functions. This procedure provides a convenient way to organize the contributions to the cross section in terms of powers of m Q /p.…”

Section: The Fragmentation-function Approachmentioning

confidence: 99%

See 1 more Smart Citation

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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Section: The Nrqcd Factorization Approachmentioning

confidence: 99%

Section: The Fragmentation-function Approachmentioning

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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show abstract

“…However, CO mechanism seems to encounter difficulties when the polarization of J/ψ is also taken into consideration [7,8]. To exploit the underlying physics, lots of efforts have been made, either by introducing new channels [9][10][11] or by proposing other mechanisms [12,13]. * An expanded version based on Ref.…”

Section: Introductionmentioning

confidence: 99%

Complete next-to-leading order calculation of theJ/ψandψ′production at hadron colliders

2011

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A complete next-to-leading order (NLO) calculation in αs for the J/ψ and ψ ′ prompt production at the Tevatron, LHC, and RHIC in nonrelativistic QCD is presented. We argue that the nextto-next-to-leading order (NNLO) color-singlet contribution may not be so important as to resolve the large discrepancy between theory and experiment in J/ψ large pT production cross sections. Therefore, a complete NLO calculation, including both color-singlet and color-octet contribution, is necessary and essential to give a good description for J/ψ and ψ ′ production. We also study the methods to fit the long-distance matrix elements using either two linear combined matrix elements or three matrix elements, and find these two methods can give consistent results. Compared with the measurements at the LHC and RHIC for prompt J/ψ and ψ ′ production, our predictions are found to agree with all data. In particular, the recently released large pT data (up to 60-70 GeV) at the LHC are in good agreement with our predictions. Our results imply that the universality of coloroctet matrix elements holds approximately in charmonium hadroproduction, when one uses fixed order perturbative calculation to describe data (the data in small pT region are not included). Our work may provide a new test for the universality of color-octet matrix elements, and the color-octet mechanism in general.

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“…In the NRQCD approach this singularity is seen to be correctly canceled by higher order corrections to the corresponding colour octet matrix element. One interesting recent development along these lines is the discovery [11] that the definition of the NRQCD matrix elements must be updated for this property to continue to hold to next-to-next-to-leading order.…”

Section: J/ψ Productionmentioning

confidence: 99%