Color-transfer enhancement for heavy quarkonium production

Nayak, Gouranga C.; Qiu, Jianwei; Sterman, George

doi:10.1103/physrevd.77.034022

Cited by 27 publications

(26 citation statements)

References 39 publications

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“…That is because the NRQCD factorization formula is designed to take into account only a heavy quark and a heavy antiquark at small relative velocity [635,636]. If an additional heavy Q orQ is nearly co-moving with a QQ pair, a color-octet QQ pair could evolve into a color-singlet QQ pair by exchanging soft gluons with the additional Q orQ.…”

Section: Difficulties In Establishing Nrqcd Factorizationmentioning

confidence: 99%

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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: Difficulties In Establishing Nrqcd Factorizationmentioning

confidence: 99%

“…Measurements of such processes would provide tests of the NRQCD factorization formalism. They would also provide information about the color-transfer mechanism [635,636] (see Sect. 4.1.7), which involves soft-gluon exchanges between comoving heavy particles and is known to violate standard NRQCD factorization.…”

Section: Fig 59mentioning

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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“…Here, and throughout this paper, we work in the Feynman gauge. 5 If the spectator antiquark line that connects the B meson to the light meson carries a C À momentum whose invariant square is of order Ã 3 QCD =Q, then that momentum is said to be in the softcollinear or messenger region [20]. Such a momentum arises from a small part of the phase space in which a gluon on the B-meson side of the soft-collinear spectator line carries away most of p l and a gluon on the light-meson side of the softcollinear spectator line carries away most of p k " q .…”

Section: Leading Momentum Configurations In Feynman Diagramsmentioning

confidence: 97%

“…In the case of hard-scattering processes that involve heavy-quarkonium states, it has been proposed that the effective theory nonrelativistic QCD (NRQCD) could be used to describe the separation of perturbative effects that produce a heavy-quark pair from the nonperturbative effects that bring about the evolution of the heavy-quark pair into the quarkonium bound state [1]. Recently, progress has been made in understanding factorization issues in inclusive heavy-quarkonium production processes [2][3][4][5]. However, a proof of factorization to all orders in QCD perturbation theory is still lacking for inclusive quarkonium production.…”

Section: Introductionmentioning

confidence: 99%

Factorization in exclusive quarkonium production

2010

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We present factorization theorems for two exclusive heavy-quarkonium production processes: production of two quarkonia in e^+e^- annihilation and production of a quarkonium and a light meson in B-meson decays. We describe the general proofs of factorization and supplement them with explicit one-loop analyses, which illustrate some of the features of the soft-gluon cancellations. We find that violations of factorization are generally suppressed relative to the factorized contributions by a factor v^2m_c/Q for each S-wave charmonium and a factor m_c/Q for each L-wave charmonium with L>0. Here, v is the velocity of the heavy quark or antiquark in the quarkonium rest frame, Q=sqrt{s} for e^+e^- annihilation, Q=m_B for B-meson decays, sqrt{s} is the e^+e^- center-of-momentum energy, m_c is the charm-quark mass, and m_B is the B-meson mass. There are modifications to the suppression factors if quantum-number restrictions apply for the specific process.Comment: 69 pages, 12 figures, 2 tables. v2: Version published in Physical Review

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“…Now let us discuss the hadroproduction of v cJ from color singlet c c pair at high-energy colliders. If the factorization theorem is valid [1,33,34,[37][38][39][40][41][42][43][44][45][46] then the v cJ production from the color singlet c c pair at high energy colliders is given by…”

Section: Closed-time Path Integral Formalism and The Generating Functmentioning

confidence: 99%