Measurement of differential cross sections for antiproton-proton annihilation into charged pion and kaon pairs between 0.79 and 243 GeV/c

Eisenhandler, E.; Gibson, W. R.; Hojvat, C.; Kalmus, P. I. P.; Lee, L.C.Y.; Pritchard, T. W.; Usher, E.C.; Williams, D.T.; Harrison, M.; Range, W.H.; Kemp, M.A.R.; Rush, A.D.; Woulds, J.N.; Arnison, G.; Astbury, A.; Jones, David P.H.; Parsons, A.S.L.

doi:10.1016/0550-3213(75)90461-7

Cited by 91 publications

(30 citation statements)

References 30 publications

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“…The mixing angle is however determined from the f 2 (1560) and f 2 (1750) couplings to K 0 S K 0 S and not from the GMO formula. For the higher-mass region, the authors use the Crystal Barrel data onpp in flight discussed in Section 6.1 and data onpp → + − data obtained with a polarised target [935]. Five tensor states were required to describe the data, f 2 (1920), f 2 (2000), f 2 (2020), f 2 (2240), f 2 (2300) (see Table 16).…”

Section: J P C = 2 ++ and Search For The Tensor Glueballmentioning

confidence: 99%

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Glueballs, hybrids, multiquarks

2007

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Glueballs, hybrids and multiquark states are predicted as bound states in models guided by quantum chromo dynamics (QCD), by QCD sum rules or QCD on a lattice. Estimates for the (scalar) glueball ground state are in the mass range from 1000 to 1800 MeV, followed by a tensor and a pseudoscalar glueball at higher mass. Experiments have reported evidence for an abundance of meson resonances with 0 −+ , 0 ++ and 2 ++ quantum numbers. In particular, the sector of scalar mesons is full of surprises starting from the elusive and mesons. The a 0 (980) and f 0 (980), discussed extensively in the literature, are reviewed with emphasis on their Janus-like appearance as KK molecules, tetraquark states or qq mesons. Most exciting is the possibility that the three mesons f 0 (1370), f 0 (1500), and f 0 (1710) might reflect the appearance of a scalar glueball in the world of quarkonia. However, the existence of f 0 (1370) is not beyond doubt and there is evidence that both f 0 (1500) and f 0 (1710) are flavour octet states, possibly in a tetraquark composition. We suggest a scheme in which the scalar glueball is dissolved into the wide background into which all scalar flavour-singlet mesons collapse.There is an abundance of meson resonances with the quantum numbers of the . Three states are reported below 1.5 GeV/c 2 whereas quark models expect only one, perhaps two. One of these states, (1440), was the prime glueball candidate for a long time. We show that (1440) is the first radial excitation of the meson.Hybrids may have exotic quantum numbers which are not accessible by qq mesons. There are several claims for J P C = 1 −+ exotics, some of them with properties as predicted from the flux tube model interpreting the quark-antiquark binding by a gluon string. The evidence for these states depends partly on the assumption that meson-meson interactions are dominated by s-channel resonances. Hybrids with non-exotic quantum numbers should appear as additional states. Light-quark mesons exhibit a spectrum of (squared) masses which are proportional to the sum of orbital angular momentum and radial quantum numbers. Two states do not fall under this classification. They are discussed as hybrid candidates.The concept of multiquark states has received revived interest due to new resonances in the spectrum of states with open and hidden charm. The new states are surprisingly narrow and their masses and their decay modes often do not agree with simple quark-model expectations.Lattice gauge theories have made strong claims that glueballs and hybrids should appear in the meson spectrum. However, the existence of a scalar glueball, at least with a reasonable width, is highly questionable. It is possible that hybrids will turn up in complex multibody final states even though so far, no convincing case has been made for them by experimental data. Lattice gauge theories fail to identify the nonet of scalar mesons. Thus, at the present status of approximations, lattice gauge theories seem not to provide a trustworthy guide into unknown territory ...

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Section: J P C = 2 ++ and Search For The Tensor Glueballmentioning

confidence: 99%

“…Tensor mesons from Crystal Barrel data on pp annihilation in flight[930][931][932] and frompp → + − data obtained with a polarised target[935] …”

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confidence: 99%

Glueballs, hybrids, multiquarks

2007

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“…In this work we focus on the electron-positron pair production, denoted the signal reaction, and on the charged pion pair production, denoted the background reaction. The cross section of hadron production is expected to be much larger than that of leptons: for charged pions it is ∼ 10 6 times larger than for e + e − production [21][22][23]. The signal and the background reactions have very similar kinematics because the mass of the electron is sufficiently close to the pion mass in the energy scale of the PANDA experiment (for the antiproton beam momentum in the laboratory system p lab = 3.3 GeV/c the range of the electron laboratory momentum is 0.58-3.82 GeV/c, while for the pions it is 0.92-3.5 GeV/c).…”

Section: Basic Formalismmentioning

confidence: 99%

“…-At low energy, the angular distribution of the final state pions is measured [22]. A baryon exchange model was developed in ref.…”

Section: The Background Reactionmentioning

confidence: 99%