Diffractive production of 3π states at 63 and 94 GeV

Daum, C.; Glaubman, M.; Wickens, F. J.; Hertzberger, L.O.; Deurzen, P. Van; Männer, W.; Blanar, G.; Hyams, B.; Dietl, H.; Damerell, C.; Lütjens, G.; Blakey, I.; Klanner, R.; Thompson, G.; Gillman, A. R.; Polok, G.; Spalding, W. J.; Hardwick, C.; Alper, B.; Stierlin, U.; Lütz, G.; Cashmore, R.J.; Różańska, M.; Rybicki, K.; Dwuraźny, A.; Becker, H.; Hoogland, W.; Weilhammer, P.; Loken, J.; Turała, M.; Cerrada, M.; Hotchkiss, M.J.; Bowler, M. G.; Tiecke, H.; Turnau, J.; Peters, Sarah; Chabaud, V.; Gallivan, J.; Lorenz, E.

doi:10.1016/0550-3213(81)90123-1

Cited by 86 publications

(47 citation statements)

References 40 publications

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“…Veto sandwiches around the target and in front of magnets were used to suppress events with secondaries out of aperture. Most results on meson spectroscopy are devoted to diffractive production of meson resonances in pion and Kaon beams [218][219][220][221][222][223]. In these studies two triggers were used, either an unbiased trigger asking only for a preset multiplicity in forward direction, or a trigger with an additional cut on the momentum squared transfer, |t| > 0.16 (GeV/c) 2 .…”

Section: The Wa3 Experimentsmentioning

confidence: 99%

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: The Wa3 Experimentsmentioning

confidence: 99%

Glueballs, hybrids, multiquarks

2007

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“…A detailed description of the model can be found in Refs. [11,18,34,35,36]. Here, we only briefly summarize the relevant formulae.…”

Section: K-matrix Approachmentioning

confidence: 99%

“…where the production couplings f pa and f pb are complex numbers [11,34]. Furthermore, one can assume f pa to be real.…”

Section: K-matrix Approachmentioning

confidence: 99%

Clues for the existence of twoK1(1270)resonances

et al. 2007

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The axial vector meson K1(1270) was studied within the chiral unitary approach, where it was shown that it has a two-pole structure. We reanalyze the high-statistics WA3 experiment K − p → K − π + π − p at 63 GeV, which established the existence of both K1(1270) and K1(1400), and we show that it clearly favors our two-pole interpretation. We also reanalyze the traditional K-matrix interpretation of the WA3 data and find that the good fit of the data obtained there comes from large cancellations of terms of unclear physical interpretation.

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“…For the 1 þþ 0 þ S wave shown in Fig. 2(a) it is well known that there is a significant contribution of nonresonant production through the Deck effect [24], indicated by the dotted line. Its interference with the a 1 ð1260Þ (dashed line) shifts the peak in the data to a slightly lower value than the peak position of the resonance.…”

mentioning

confidence: 97%

Observation of aJPC=1−+Exotic Resonance in Diffractive Dissociation of190 GeV/c
Alekseev¹,
Alexakhin²,
Alexandrov³
et al. 2010
Phys. Rev. Lett.
119
7
70
2
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The COMPASS experiment at the CERN SPS has studied the diffractive dissociation of negative pions into the π- π- π+ final state using a 190 GeV/c pion beam hitting a lead target. A partial wave analysis has been performed on a sample of 420,000 events taken at values of the squared 4-momentum transfer t' between 0.1 and 1 GeV2/c2. The well-known resonances a1(1260), a2(1320), and π2(1670) are clearly observed. In addition, the data show a significant natural-parity exchange production of a resonance with spin-exotic quantum numbers J(PC)=1-+ at 1.66 GeV/c2 decaying to ρπ. The resonant nature of this wave is evident from the mass-dependent phase differences to the J(PC)=2-+ and 1++ waves. From a mass-dependent fit a resonance mass of (1660±10(-64)(+0)) MeV/c2 and a width of (269±21(-64)(+42)) MeV/c2 are deduced, with an intensity of (1.7±0.2)% of the total intensity.

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Diffractive production of 3π states at 63 and 94 GeV

Cited by 86 publications

References 40 publications

Glueballs, hybrids, multiquarks

Glueballs, hybrids, multiquarks

Clues for the existence of twoK1(1270)resonances

Observation of aJPC=1−+Exotic Resonance in Diffractive Dissociation of190 GeV/c
Alekseev¹,
Alexakhin²,
Alexandrov³
et al. 2010
Phys. Rev. Lett.
119
7
70
2
View full text Add to dashboard Cite

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Diffractive production of 3π states at 63 and 94 GeV

Cited by 86 publications

References 40 publications

Glueballs, hybrids, multiquarks

Glueballs, hybrids, multiquarks

Clues for the existence of twoK1(1270)resonances

Observation of aJPC=1−+Exotic Resonance in Diffractive Dissociation of190 GeV/cAlekseev1, Alexakhin2, Alexandrov3 et al. 2010Phys. Rev. Lett.1197702View full textAdd to dashboardCite

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Observation of aJPC=1−+Exotic Resonance in Diffractive Dissociation of190 GeV/c
Alekseev¹,
Alexakhin²,
Alexandrov³
et al. 2010
Phys. Rev. Lett.
119
7
70
2
View full text Add to dashboard Cite