Exotic mesons

Landsberg, L.G.

doi:10.3367/ufnr.0160.199003a.0001

Cited by 21 publications

(4 citation statements)

References 9 publications

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“…As a result, the number of the events for π − + p → φ + n N n (φ) = 1670 ± 410 (13) and the value of the total cross section for OZI suppressed reaction (6) at P π − =32.5 GeV σ(π − +p → φ+n)| Pπ=32.5 GeV = (11.5±3.3)·10 −33 cm 2 (14) were obtained. The quoted error is largely due to systematic uncertainties associated with the normalization of the cross sections and with the separation of the contributions from different reaction channels of (10).…”

Section: For Vector Meson Nonetmentioning

confidence: 99%

“…Recent years have seen a revived interest in the OZI rule. First, intensive searches for exotic hadrons (see the surveys in [5][6][7][8][9][10] and references therein) are greatly facilitated by choosing production reactions in which the formation of conventional particles is suppressed by the OZI rule [11][12][13][14]. Since this rule may be significantly violated for exotic hadrons because of their complex color structure, signals from exotic and cryptoexotic particles are expected to benefit from more favorable background conditions in OZI-suppressed production processes.…”

Section: For Vector Meson Nonetmentioning

confidence: 99%

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Study of the OZI selection rule in hadronic processes

Golovkin

Кожевников

Kubarovsky

et al. 1997

Z Phys A - Particles and Fields

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In the experiments with LEPTON-F and SPHINX spectrometers the pion-induced charged exchange reactions π − + p → φ + n and π − + p → ω + n at P π − =32.5 GeV, as well as proton-induced diffractive reactions p + N → [pφ] + N and p + N → [pω] + N at E p =70 GeV were studied. The comparison of the cross-sections for φ and ω-production in these reactions is used for testing the OZI selection rule in hadronic processes. It has been demonstrated that in pion reactions the ratio of the yields of φ and ω-mesons R(φ/ω) = (3 ± 1) · 10 −3 is in a good agreement with naive quark model prediction based on the mixing in vector meson nonet and on the OZI rule (R(φ/ω) OZI = tg 2 ∆θ V 4 · 10 −3 ). At the same time in proton reactions the effective ratio of φ and ω yields is ∼ (4 ÷ 7) · 10 −2 , i.e. a strong violation of the OZI rule is observed in proton-nucleon interactions. This violation can be in favor of possible existence of some exotic ss component in the quark structure of protons. : 13.85.Fb; 14.40.Cs; 14.40.Ev PACS The OZI ruleThe selection rule for connected and disconnected quark diagrams that is referred to as the OZI rule has been known for a long time [1][2][3]. According to this rule, processes involving the annihilation or creation of a quark-antiquark pair entering into the composition of the same hadron are forbidden or, strictly speaking, strongly suppressed. The OZI rule may be illustrated by the diagrams for the production and decay of the vector mesons ω and φ (see Fig. 1).Let us consider exclusive reaction of qq pair production A + B → C 1 + C 2 + ... + C n + (qq) (q = u; d; s) with particles A, B, C i without strange quarks (see [4]). The ratio of amplitudes of the corresponding reactionsdetermines the violation of the OZI rule in these processes (the OZI rule demands Z = 0). It is well known that neutral mesons from meson nonets are the mixture of SU(3) octet and singlet states For vector meson nonetHere θ V is a mixing angle for vector nonet; α (or3 o is an ideal mixing angle (for this ideal mixing |φ >= −|ss >; |ω >= 1 √ 2 (uū + dd) >), as on diagrams in Fig. 1).For the ratio of amplitudes of φ and ω production the following expression was derived [4]:Thus the ratio of corresponding cross sections is Fig. 1. Diagrams for: a,b OZI-allowed and c,d OZI-suppressed production and decay processes: a reaction π − + p → ω + n, b decay ω → π + π − π 0 (connected quark diagrams); c reaction π − + p → φ + n, and d decay φ → π + π − π 0 (disconnected quark diagrams)where f is a kinematical phase space correction factor. Because the phase of β is unkown it is only possible to estimate the limits for the OZI violation factor |Z|:Many measurements of the R ratio and testing of the OZI rule in different reactions were made in the last thirty years. It is the generalization of the OZI rule for the processes with charmed quarks which explaines the anomalously small decay width of the J/ψ particle, representing a bound cc state (in analogy with φ meson). Recent years have seen a revived interest in the OZI rule. First, in...

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Section: For Vector Meson Nonetmentioning

confidence: 99%

Section: For Vector Meson Nonetmentioning

confidence: 99%

Study of the OZI selection rule in hadronic processes

Golovkin

Кожевников

Kubarovsky

et al. 1997

Z Phys A - Particles and Fields

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“…The central problem of light hadron spectroscopy has been the problem of the scalar f 0 (980) and a 0 (980) mesons. It is well known that these states possess peculiar properties from the naive quark (q q) model point of view, see, for example, the reviews [1][2][3][4][5]. To clarify the nature of these mesons a number of models has been suggested.…”

Section: Introductionmentioning

confidence: 99%

“…but from experiment [16] BR(J/ψ → γgg → γf 0 → γππ) < 1, 4 • 10 −5 (4) and [17] BR(J/ψ → γgg → γη ′ (958)) = 4, 3 • 10 −3 .…”

Section: Introductionmentioning

confidence: 99%

Search for the scalar a[sub 0] and f[sub 0] mesons in the φ radiative decays

Achasov¹,

Gubin²

1998

AIP Conference Proceedings

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The potentialities of the production of the a 0 and f 0 mesons in the φ radiative decays are considered based on a new two-channel analysis of the ππ scattering in a energy region near 1 GeV. We predict BR(φ → γf 0 (980)) ∼ 10 −5 − 10 −4 that is a great value for the decay forbidden by the Okubo-Zweig-Iizuka rule.We discuss the four-quark, KK-molecule and two-quark scenarios for the a 0 and f 0 mesons. It is presented arguments that the e + e − -colliders and especially the φ factories give the possibility to choose a single one out of them.

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Hybrid mesons and instantons

Martynenko

1993

Russ Phys J

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Exotic mesons

Cited by 21 publications

References 9 publications

Study of the OZI selection rule in hadronic processes

Study of the OZI selection rule in hadronic processes

Search for the scalar a[sub 0] and f[sub 0] mesons in the φ radiative decays

Hybrid mesons and instantons

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