Total cross section for hadron production by e+e−-annihilation at center of mass energies between 3.6 and 5.2 GeV

Brandelik, R.; Braunschweig, W.; Martyn, H. U.; Sander, H. G.; Schmitz, D.; Sturm, Walter; Wallraff, W.; Cords, D.; Felst, R.; Fries, Rainer J.; Gadermann, E.; Hultschig, H.; Joos, P.; Koch, W.; Kötz, U.; Krehbiel, H.; Kreinick, D. L.; Lynch, H. L.; McNeely, W.A.; Mikenberg, G.; Moffeit, K. C.; Notz, D.; Rüsch, R.; Schliwa, Manfred; Shapira, A.; Wiik, B.H.; Wolf, G.; Ludwig, J.; Mess, K. H.; Petersen, A.; Poelz, G.; Ringel, Jeanne S.; Römer, O.; Sauerberg, K.; Schmüser, Peter; Boer, W. De; Buschhorn, G.; Fues, W.; Gagern, C. von; Grindhammer, G.; Gunderson, B.; Kotthaus, R.; Lierl, H.; Oberlack, H.; Orito, S.; Suda, T.; Totsuka, Y.; Yamada, Shoichi

doi:10.1016/0370-2693(78)90807-9

Cited by 104 publications

(44 citation statements)

References 11 publications

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“…at 90% C.L.. A puzzling phenomenon of the Y(4260) is that it is absent in the R value scan [137,138,139,140,129,141], which is the challenge to the traditional vector charmonium interpretation of the Y(4260). We note that the R value denotes the ratio of the rate of hadron production to that for muon pairs in the annihilation of e + e − pair, i.e., R = σ(e + e − → hadrons)/σ(e + e − → µ + µ − ).…”

Section: Its Open Charm Decay Modesmentioning

confidence: 99%

The hidden-charm pentaquark and tetraquark states

et al. 2016

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In the past decade many charmonium-like states were observed experimentally. Especially those charged charmoniumlike Z c states and bottomonium-like Z b states can not be accommodated within the naive quark model. These charged Z c states are good candidates of either the hidden-charm tetraquark states or molecules composed of a pair of charmed mesons. Recently, the LHCb Collaboration discovered two hidden-charm pentaquark states, which are also beyond the quark model. In this work, we review the current experimental progress and investigate various theoretical interpretations of these candidates of the multiquark states. We list the puzzles and theoretical challenges of these models when confronted with the experimental data. We also discuss possible future measurements which may distinguish the theoretical schemes on the underlying structures of the hidden-charm multiquark states.

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Section: Its Open Charm Decay Modesmentioning

confidence: 99%

The hidden-charm pentaquark and tetraquark states

et al. 2016

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“…These states were first observed thirty years ago in e + e − annihilation as enhancements in the total hadronic cross section [7][8][9][10][11]. No update of their parameters was made until 2005, when a combined fit to the Crystal Ball [12] and BES [13] R-measurements was performed by Seth [14].…”

Section: Conventional Vectors Above Open-flavor Thresholdmentioning

confidence: 99%

“…Interestingly, from the astroparticle and cosmological side, DAMA and CoGeNT experiments have reported the observation of events compatible with a Light Dark-Matter (LDM) candidate with a mass inside the interval [5,10] GeV [411]. Such a mass range for LDM constituents is especially attractive in certain cosmological scenarios, e.g., the Asymmetric Dark Matter model where the cosmological dark matter density arises from the baryon asymmetry of the universe and is expected to have an LDM mass of order [1][2][3][4][5][6][7][8][9][10] GeV (see [412,413] and references therein).…”

Section: Invisible Decays Of ψ and υmentioning

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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“…Perturbative QCD is clearly inapplicable in the charm threshold region between 3.7 and 5 GeV where rapid variations of the cross section are observed. Data have been taken more than 15 years ago by the PLUTO [159], DASP [160], and MARK I collaborations [161]. The systematic errors of 10 to 20 % exceed the statistical errors significantly and are reflected in a sizeable spread of the experimental results.…”

Section: An Application Of R(s)mentioning

confidence: 99%

Results and techniques of multi-loop calculations

Steinhauser

2002

Physics Reports

100

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In this review some recent multi-loop results obtained in the framework of perturbative Quantum Chromodynamics (QCD) and Quantum Electrodynamics (QED) are discussed. After reviewing the most advanced techniques used for the computation of renormalization group functions, we consider the decoupling of heavy quarks. In particular, an effective method for the evaluation of the decoupling constants is presented and explicit results are given. Furthermore the connection to observables involving a scalar Higgs boson is worked out in detail. An all-order low energy theorem is derived which establishes a relation between the coefficient functions in the hadronic Higgs decay and the decoupling constants. We review the radiative corrections of a Higgs boson into gluons and quarks and present explicit results up to order α 4 s and α 3 s , respectively. In this review special emphasis is put on the applications of asymptotic expansions. A method is described which combines expansion terms of different kinematical regions with the help of conformal mapping and Padé approximation. This method allows us to proceed beyond the present scope of exact multi-loop calculations. As far as physical processes are concerned, we review the computation of three-loop current correlators in QCD taking into account the full mass-dependence. In particular, we concentrate on the evaluation of the total cross section for the production of hadrons in e + e − annihilation. The knowledge of the complete mass dependence at order α 2 s has triggered a bunch of theory-driven analyses of the hadronic contribution to the electromagnetic coupling evaluated at high energy scales. The status is summarized in this review. In a further application four-loop diagrams are considered which contribute to the order α 2 QED corrections to the µ decay. Its relevance for the determination of the Fermi constant G F is discussed. Finally the calculation of the three-loop relation between the MS and on-shell quark mass definitions is presented and physical applications are given. To complete the presentation, some technical details are presented in the Appendix, where also explicit analytical results are listed.

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Total cross section for hadron production by e+e−-annihilation at center of mass energies between 3.6 and 5.2 GeV

Cited by 104 publications

References 11 publications

The hidden-charm pentaquark and tetraquark states

The hidden-charm pentaquark and tetraquark states

Heavy quarkonium: progress, puzzles, and opportunities

Results and techniques of multi-loop calculations

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