Pole positions of the dominant pion-pion resonances

Boháčik, J.; Kühnelt, H.

doi:10.1103/physrevd.21.1342

Cited by 9 publications

(7 citation statements)

References 19 publications

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“…The position is readily worked out with the explicit, algebraic parametrization of the phase that we are using. The result illustrates an observation made long ago [71,72,73]: The pole mass is lower than the energy at which the phase goes through 90…”

Section: The ρ Resonancesupporting

confidence: 81%

Roy equation analysis of ππ scattering

et al. 2001

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We analyze the Roy equations for the lowest partial waves of elastic ππ scattering. In the first part of the paper, we review the mathematical properties of these equations as well as their phenomenological applications. In particular, the experimental situation concerning the contributions from intermediate energies and the evaluation of the driving terms are discussed in detail. We then demonstrate that the two S-wave scattering lengths a 0 0 and a 2 0 are the essential parameters in the low energy region: Once these are known, the available experimental information determines the behaviour near threshold to within remarkably small uncertainties. An explicit numerical representation for the energy dependence of the S-and P -waves is given and it is shown that the threshold parameters of the Dand F -waves are also fixed very sharply in terms of a 0 0 and a 2 0 . In agreement with earlier work, which is reviewed in some detail, we find that the Roy equations admit physically acceptable solutions only within a band of the (a 0 0 ,a 2 0 ) plane. We show that the data on the reactions e + e − → π π and τ → π π ν reduce the width of this band quite significantly. Furthermore, we discuss the relevance of the decay K → π π e ν in restricting the allowed range of a 0 0 , preparing the grounds for an analysis of the forthcoming precision data on this decay and on pionic atoms. We expect these to reduce the uncertainties in the two basic low energy parameters very substantially, so that a meaningful test of the chiral perturbation theory predictions will become possible.

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Section: The ρ Resonancesupporting

confidence: 81%

Roy equation analysis of ππ scattering

et al. 2001

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“…References [13,14] focus their attention on nn scattering. In contradistinction to n x scattering, which involves reionances in different channels f J = 0.1) and where ex-, , perimental data are not as precise and abundant, the reaction e+e-+ x+?rserves as a filter to select precisely the J = 1 channel.…”

Section: Discussion Of Results and Conclusionmentioning

confidence: 99%

Mass and width of theρ0from anS-matrix approach toe+
Bernicha
¹
,
Castro
²
,
Pestieau
³

1994
Phys. Rev. D
48
9
69
1
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W e determine the mass width o f the meson by applying the S-matrix formalism t o the reaction e+ei n+n-in the timelike region. W e obtain M p = (757.5 f 1.5) MeV and rp = (142.5 * 3.5) MeV, which are significantly smaller than the values quoted by the Particle Data Group. These values are almost independent o f the specific form used t o model the background. PACS number(s): 14.40.Cs, 11.55.Bq. 13.40.Gp, 13.65.-ti

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“…Other authors have also used the parameterizations with the Jost functions in analyzing the S-wave ππ scattering in the one-channel approach[23] and in the two-channel one[24]. In the latter work, considering ππ and KK channels, the c.m.…”

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confidence: 98%