A NEW ANALYSIS OF THE π+π- AND π0π0 DATA

Kamiński, R.; Leśniak, L.; Rybicki, K.

doi:10.1142/9789812791351_0035

Cited by 49 publications

(113 citation statements)

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“…Fig. 2 shows the experimental determinations of η 0 0 based on the elastic amplitude from refs [58] and [59]. The result of the K-matrix fit performed in ref.…”

Section: 3mentioning

confidence: 99%

Couplings of light I=0 scalar mesons to simple operators in the complex plane

Moussallam

2011

Eur. Phys. J. C

141

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The flavour and glue structure of the light scalar mesons in QCD are probed by studying the couplings of the I = 0 mesons σ(600) and f 0 (980) to the operatorsqq, α s G 2 and to two photons. The Roy dispersive representation for the ππ amplitude t 0 0 (s) is used to determine the pole positions as well as the residues in the complex plane. On the real axis, t 0 0 is constrained to solve the Roy equation together with elastic unitarity up to the KK threshold leading to an improved description of the f 0 (980). The problem of using a two-particle threshold as a matching point is discussed. A simple relation is established between the coupling of a scalar meson to an operator j S and the value of the related pion form-factor computed at the resonance pole. Pion scalar form-factors as well as two-photon partial-wave amplitudes are expressed as coupled-channel Omnès dispersive representations. Subtraction constants are constrained by chiral symmetry and experimental data. Comparison of our results for theqq couplings with earlier determinations of the analogous couplings of the lightest I = 1 and I = 1/2 scalar mesons are compatible with an assignment of the σ, κ, a 0 (980), f 0 (980) into a nonet. Concerning the gluonic operator α s G 2 we find a significant coupling to both the σ and the f 0 (980).

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“…Fig. 2 shows the experimental determinations of η 0 0 based on the elastic amplitude from refs [58] and [59]. The result of the K-matrix fit performed in ref.…”

Section: 3mentioning

confidence: 99%

Couplings of light I=0 scalar mesons to simple operators in the complex plane

Moussallam

2011

Eur. Phys. J. C

141

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“…Scalar-isoscalar phase shifts [1] for the solutions "up-flat" (open circles) and "down-flat" (full circles); the round curve indicates the region where the "up-down" ambiguity leads to the largest differences between the two solutions. the data of [1]. In the S2-wave we have used the data from solution A of Hoogland et.…”

Section: Analysis Of the Datamentioning

confidence: 99%

“…Two of these solutions, called "steep", violate unitarity and can be rejected as non-physical [1,2]. The phase shifts for the two left "flat" data sets are presented in Fig.…”

Section: Introductionmentioning

confidence: 99%

ππ scattering amplitudes constrained by Roy's equations

Kamiński

Leśniak

Loiseau

2007

Nuclear Physics B - Proceedings Supplements

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The scalar-isoscalar, scalar-isotensor and vector-isovector ππ amplitudes have been fitted simultaneously to experimental data and to to Roy's equations. Resulting ππ phase shifts up to 1600 MeV and near threshold observables have been analyzed. Only the amplitudes fitted to the "down-flat" set of phase shifts in scalarisoscalar wave fulfill crossing symmetry conditions and can be regarded as physical.

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“…In 1997 a new analysis of the π − p ↑ → π + π − n reaction on a polarized target was performed in the m ππ effective mass range from 600 to 1600 MeV [1]. For the first time the pseudoscalar (π-exchange) amplitude was separated from the pseudovector (a 1 -exchange) amplitude in the region of the the four-momentum transfer squared from −0.005 to −0.2 (GeV/c) 2 .…”

Section: Introductionmentioning

confidence: 99%

Roy’s equations and the ππ experimental data

Kamiński¹,

Leśniak²,

Loiseau³

2004

AIP Conference Proceedings

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Roy's equations are used to check if the scalar-isoscalar ππ scattering amplitudes fitted to experimental data fulfill crossing symmetry conditions. It is shown that the amplitudes describing the "down-flat" phase shift solution satisfy crossing symmetry below 1 GeV while the amplitudes fitted to the "up-flat" data do not. In this way the long standing "up-down" ambiguity in the phenomenological determination of the scalar-isoscalar ππ amplitudes has been resolved confirming the independent result of the recent joint analysis of the π + π − and π 0 π 0 data. IntroductionIn 1997 a new analysis of the π − p ↑ → π + π − n reaction on a polarized target was performed in the m ππ effective mass range from 600 to 1600 MeV [1]. For the first time the pseudoscalar (π-exchange) amplitude was separated from the pseudovector (a 1 -exchange) amplitude in the region of the the four-momentum transfer squared from −0.005 to −0.2 (GeV/c) 2 . Below 1000 MeV, where the S-and P -waves strongly interfere, the partial wave analysis of the π + π − data provided us with two scalarisoscalar solutions, called "up" and "down", which differ by their intensities. Lack of information on a sign difference between the phases of the S-and P -waves near the position of the ρ resonance led us to other two branches of the "up" and "down" amplitudes named "steep" and "flat". It was shown in [2] that both "up-steep" and "down-steep" S-wave isoscalar amplitudes significantly violate unitarity below 1 GeV * Unité de Recherche des Universités Paris 6 et Paris 7, associée au CNRS † This work has been performed in the framework of the IN2P3-Polish Laboratories Convention (project number 99-97).

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A NEW ANALYSIS OF THE π⁺π^- AND π⁰π⁰ DATA

Cited by 49 publications

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Couplings of light I=0 scalar mesons to simple operators in the complex plane

Couplings of light I=0 scalar mesons to simple operators in the complex plane

ππ scattering amplitudes constrained by Roy's equations

Roy’s equations and the ππ experimental data

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