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- Fäldt, Göran, et al.
(författare)
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Comparison of the pp → π+pn and pp → π+d production rates
- 2017
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 770, s. 146-148
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Tidskriftsartikel (refereegranskat)abstract
- Fully constrained bubble chamber data on the pp -> pi(+)pn and pp -> pi(+)d reactions are used to investigate the ratio of the counting rates for the two processes at low pn excitation energies. Whereas the ratio is in tolerable agreement with that found in a high resolution spectrometer experiment, the angular distribution in the final pn rest frame shows that the deviation from the predictions of final state interaction theory must originate primarily from higher partial waves in the pn system. These considerations might also be significant for the determination of the S -wave Ap scattering length from data on the pp -> K+Lambda p reaction.
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- Fäldt, Göran, et al.
(författare)
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Coulomb-nuclear interference in pion-nucleus bremsstrahlung
- 2009
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 79:1, s. 014607-
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Tidskriftsartikel (refereegranskat)abstract
- Pion-nucleus bremsstrahlung offers a possibility of measuring the structure functions of pion-Compton scattering from a study of the small-momentum-transfer region where the bremsstrahlung reaction is dominated by the single-photon-exchange mechanism. The corresponding cross-section distribution is characterized by a sharp peak at small momentum transfers. But there is also a hadronic contribution that is smooth and constitutes an undesired background. In this article the modification of the single-photon-exchange amplitude by multiple Coulomb scattering is investigated as well as the Coulomb-nuclear interference term.
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- Fäldt, Göran
(författare)
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Entanglement in joint Lambda(Lambda)over-bar decay
- 2015
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 51:7
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the joint decay in the reaction . This reaction may provide information on the electromagnetic form factors of the Lambda baryon, in the time-like region. We present a conventional diagram-based calculation where production and decay steps are coherent and summations over final-state proton and anti-proton spins are performed. The resulting cross-section distribution is explicitly covariant as it is expressed in scalar products of the four-momentum vectors of the participating particles. We compare this calculation with that of the folding method which we extend and make explicitly covariant. In the folding method production and decay distributions, not amplitudes, are folded together. Of particular importance is then a correct counting of the number of possible intermediate-hyperon-spin states.
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- Fäldt, Göran
(författare)
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Entanglement in joint Lambda(Lambda)over-bar decay; con
- 2022
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Ingår i: European Physical Journal A. - : Springer Nature. - 1434-6001 .- 1434-601X. ; 58:11
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Tidskriftsartikel (refereegranskat)abstract
- We have previously investigated joint AA decay in the reaction e(+)e(-) -> gamma Lambda(-> p pi(-))(Lambda) over bar(-> (p) over bar pi(+)). The cross-section-distribution functions encountered were relativistically covariant and expressed in terms of scalar products of the four-momentum vectors of the particles involved. In the present, sequel investigation, we work instead in the Lambda(Lambda) over bar rest system and with three-momentum scalars. In this configuration our results become directly comparable to those of others, including experiment.
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- Fäldt, Göran, et al.
(författare)
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Estimation of the ratio of the pn -> pn pi(0)pi(0)/pn -> d pi(0)pi(0) cross sections
- 2011
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 701:5, s. 619-622
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Tidskriftsartikel (refereegranskat)abstract
- Evidence has recently been presented for the existence of a dibaryon of mass 2380 MeV/c(2) and width 70 MeV/c(2), which decays strongly into the d pi(0)pi(0) channel [M. Bashkanov, et al., Phys. Rev. Lett. 102 (2009) 052301; P. Adlarson, et al., arXiv:1104.0123]. The decay rate of such a hypothesised dibaryon into the {pn}i=0 pi(0)pi(0) channel is estimated in a weakly model-dependent way by using final state interaction theory. It is shown that, if the resonance exists, it should show up as strongly in this channel as in d pi(0)pi(0). The sum of the two decay modes would saturate most of the inelasticity predicted in the relevant partial waves in the 2380 MeV/c(2) region.
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