Coupled-channel effective-range expansion of low energy <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" altimg="si1.gif" overflow="scroll"><mml:mrow><mml:mover accent="true"><mml:mo>N</mml:mo><mml:mo>¯</mml:mo></mml:mover><mml:mo>N</mml:mo></mml:mrow></mml:math> scattering

Mahalanabis, J.; Pirner, H. J.; Shibata, T. A.

doi:10.1016/0375-9474(88)90552-0

Cited by 41 publications

(20 citation statements)

References 14 publications

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“…Moreover our calculation reproduces the observed T=0 enhancement over T= 1 of annihilation cross sections for Plab < 400 MeV/c. The examined models, however, can not fully reproduce the very strong isospin dependence for P-wave annihilation from recent/5 (SHe, 4He) measurements in [23], where an annihilation cross section ratio ~r(T--1)/ a(T=0)=0.35 containing about 50% P-waves is reported, in accordance with the fits of J. Mahalanabis et al [24]. We obtain 0.7 for the P-wave average of this ratio, what may indicate the need of an energy and isospin dependence of the phenomenological annihilation potentials.…”

Section: Vn~ (R) = U (R) + W(r)supporting

confidence: 86%

Protonium annihilation in optical models

Carbonell

Ihle

Richard

1989

Z. Physik A - Atomic Nuclei

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We calculate the wave-functions, energy shifts and widths of low lying protonium states using different optical potentials (Dover-Richard, Kohno-Weise). The importance of tensor and isospin coupling is studied and the initial state distortion is compared for protonium annihilation and pp annihilation in flight at low energy. We study the range of distances at which annihilation actually occurs in protonium. We also analyse the effect of the initial state interaction on two meson branching ratios and underline that it may dramatically change the predictions of those microscopic models which are based only on phase space and simple quark diagrams.

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Section: Vn~ (R) = U (R) + W(r)supporting

confidence: 86%

Protonium annihilation in optical models

Carbonell

Ihle

Richard

1989

Z. Physik A - Atomic Nuclei

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“…The parameters set (12) is just this updated version. The effective range solution [29] fairly well fits the low energy cross sections [25]- [28] which is an indication that the same is true for our parameter set (12). We urge our colleagues who are in possession of the experimental data to persuade the analysis whith the parameter sets [13,14].…”

supporting

confidence: 51%

“…The only substantial new piece of information concerns the total and annihilationpp andnp cross sections down to p Lab = 35 MeV/c [25,26]. However in the analysis of these data [27,28] use was made of the effective range solution [29] performed in 1988 which was later updated in 1991 [14] partly by the original authors. The parameters set (12) is just this updated version.…”

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confidence: 99%

Model-independent view on the low-mass proton-antiproton enhancement

2004

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We present a simple interpretation of the recently observed nearthreshold proton-antiproton enhancement. It is described by a set of low-energy parameters deduced from the analysis of NN experiments at LEAR. We predict a related effect in photoproduction reaction under study by CLAS collaboration.Low-mass baryon-antibaryon enhancement has recently been observed in the decays. On the theoretical side this discovery has been discussed by several authors [4,5,6,7]. In [4] the near-threshold effect has been considered either as a gluonic state or as a result of the quark fragmentation process. In [5] it has been attributed to the Breit colorspin interaction while in [6] it has been regarded as caused by peripheral one-pion-exchange potential. The quantum numbers corresponding to the observed enhancement are discussed in [7].The purpose of the present work is to show that the recently observed near-threshold pp enchancement may be understood invoking the knowledge on NN interaction gained at the Low Energy Antiproton Ring (LEAR) at CERN. The LEAR results may be schematically subdivided into three groups:(i) meson spectroscopy, (ii) baryonium searches, (iii) NN interaction: scattering, annihilation, protonium spectroscopy.

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“…Imposing the condition that the imaginary part of the effective range is negative we find low energy scattering parameters which interpolate between the existing ITEP [4] and CERN/Heidelberg [5] values. PACS: 13.75.-n; 13.75.cs Experiments in low energy NbT-scattering have developed greatly since the operation of the LEAR facility at CERN has started.…”

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confidence: 93%

“…A comparison of N/V-intermediate range potentials with NN-potentials is perhaps the only chance to find the range where the meson-exchange picture breaks down and subnucleonic constituent interchange takes over. Unfortunately the strong NN-annihilation masks such a simple picture and only careful comparison to the data will clarify the situation.In this paper we follow up a model independent analysis of the low energy NiV interaction with the effective range expansion [4,5]. Previously there have been two quite different solutions obtained from the data with pc<300 MeV/c.…”

mentioning

confidence: 97%

Updating the effective range expansion of low-energyN $$\bar N$$ -scattering

Pirner

Kerbikov

Mahalanabis

1991

Z. Physik A - Hadrons and Nuclei

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Low energy N?4 scattering is reanalyzed using the new data on annihilation cross-sections from CERN [1], the tip-absorption measurement from BNL [-2] and the annihilation width of the 2p state in antiprotonic hydrogen [-3]. Imposing the condition that the imaginary part of the effective range is negative we find low energy scattering parameters which interpolate between the existing ITEP [4] and CERN/Heidelberg [5] values. PACS: 13.75.-n; 13.75.cs Experiments in low energy NbT-scattering have developed greatly since the operation of the LEAR facility at CERN has started. Besides the NN and the ~N interactions antinucleon-nucleon scattering is the third test of our limited understanding of hadronic interactions. A comparison of N/V-intermediate range potentials with NN-potentials is perhaps the only chance to find the range where the meson-exchange picture breaks down and subnucleonic constituent interchange takes over. Unfortunately the strong NN-annihilation masks such a simple picture and only careful comparison to the data will clarify the situation.In this paper we follow up a model independent analysis of the low energy NiV interaction with the effective range expansion [4,5]. Previously there have been two quite different solutions obtained from the data with pc<300 MeV/c. The CERN/Heidelberg fit [5] used more experimental data than the ITEP fit [4]. But this alone cannot explain the discrepancy. In the ITEP fit the effective range is restricted to be real, whereas in the CERN/Heidelberg fit it is unconstrained besides the condition that each partial wave amplitude is unitary in the considered momentum range. The argument for * Supported by the BMFT-grant 06 HD 756 ** Institute for Theoretical and Experimental Physics (ITEP), Moscow, USSR *** Saha Institute of Nuclear Physics, Calcutta, India a real effective range in the ITEP fit was that there are no important annihilation thresholds close to the NN threshold. Then the phase space in the annihilation thresholds close to the NN threshold. Then the phase space in the annihilation channel changes only by about 10% within the interval of the incident i0 momentum 0 0, a negative imaginary r gives a consistently negative imaginary part in the denominator and 4~z consequently a positive cross section a1 = o = ~-Im F~ = o.In addition to the theoretica...

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Coupled-channel effective-range expansion of low energy N¯N scattering

Cited by 41 publications

References 14 publications

Protonium annihilation in optical models

Protonium annihilation in optical models

Model-independent view on the low-mass proton-antiproton enhancement

Updating the effective range expansion of low-energyN $$\bar N$$ -scattering

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