Total cross-section for the double charge exchange reaction $$\pi ^ + + ^4 He \to \pi ^ - + 4p$$ at 100 MeVat 100 MeV

Falomkin, I.V.; Kulyukin, M.M.; Lyashenko, V. I.; Pontecorvo, G. B.; Shcherbakov, Yu.A.; Georgescu, C.; Mihul, A.; Nichitiu, F.; Sararu, A.; Piragino, G.

doi:10.1007/bf02790621

Cited by 19 publications

(8 citation statements)

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“…The total cross section predicted by this calculation is a factor of 100 smaller than that measured in the energy region 98-156 MeV by Falomkin et al [8,9]. This theoretical re-sult is in fact consistent with the approximate agreement found with the Kaufman et al…”

Section: Previous Theoretical Worksupporting

confidence: 90%

“…More broadly motivated studies of DCX in 4 He at energies above the ∆ resonance were carried out using liquid helium bubble chambers [5,6,7]. In the energy range 98-156 MeV total cross section measurements were performed by Falomkin et al [8,9] using a high-pressure helium streamer chamber. Although some interesting phenomena were observed in these experiments, the limited statistics precluded quantitative conclusions.…”

Section: Previous Experimental Workmentioning

confidence: 99%

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Inclusive pion double charge exchange inHe4at intermediate energies

et al. 2005

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A systematic experimental study of inclusive pion double charge exchange in 4 He has been undertaken. The reaction 4 He(π + , π − )4p was observed at incident energies 120, 150, 180, 240 and 270 MeV; the 4 He(π − , π + )4n reaction was observed at incident energies 180 and 240 MeV. At each incident energy, the doubly differential cross section was measured at three to five outgoing pion laboratory angles between 25 • and 130 • . At each angle, cross sections were measured over the range of outgoing pion energies from 10 MeV up to the kinematic limit for the reaction in which the final state consists of the oppositely charged pion plus four free nucleons.The spectra of outgoing pions are strikingly different from those observed for the inclusive double charge exchange reaction in heavier nuclei, but resemble those observed in the (π − , π + ) reaction in 3 He. The forward-angle spectra in the 3 He and 4 He reactions exhibit a prominent peak at high outgoing pion energies. Interpretation of the peaks in 3 He ( 4 He) as a three-(four-)nucleon resonance is ruled out by kinematic analysis. The results of a calculation, wherein the double charge exchange reaction is assumed to proceed as two sequential single charge exchange interactions, suggest that the high-energy peak is naturally explained by this double scattering mechanism.Non-static treatment of the πN interactions and the inclusion of nuclear binding effects appear to be important in reproducing the shape of the energy spectra at forward angles.Pion double charge exchange (DCX), a nuclear reaction in which two units of charge are exchanged between a pion and a nucleus, is an important tool with which to investigate the details of the pion-nucleus interactions as well as correlations between nucleons within the nucleus. DCX is unique among pion-nuclear scattering reactions, as it must involve at least two nucleons in order to conserve charge. Thus, the physiognomy of the DCX process revealed by the experimental cross section depends on the coordinates of two particles in the wavefunction of the nucleus. As a probe of the pion-nucleus interaction, DCX may be used to isolate contributions from different types of reaction mechanisms. Other pion-nucleus reactions appear to be dominated by single scattering mechanisms, but DCX must proceed through less simple mechanisms such as double scattering, as shown in Fig. 1(a).An experimental investigation of DCX in 4 He at intermediate energies has been performed in order to study the multiple scattering mechanisms of the π-nucleus reaction directly. The choice of 4 He as a nuclear target allows an investigation of DCX in an extensively studied few-body system for which microscopic treatment of the dynamics is possible in principle. At the same time, the 4 He nucleus has a large density which may allow some effects of the nuclear medium to be investigated. The final state is also relatively simple, consisting of a pion and either four protons or four neutrons, resulting from, respectively, the reactions 4 He(π + , π − )...

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Section: Previous Theoretical Worksupporting

confidence: 90%

Section: Previous Experimental Workmentioning

confidence: 99%

Inclusive pion double charge exchange inHe4at intermediate energies

et al. 2005

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“…Later, attempts were made [17], [18] to explain the peaks qualitatively by nuclear medium effects, but no explanation based on conventional nuclear physics exists, however, for the whole set of data on DCX, and, in particular, for nuclei with N = Z. A series of experiments in search of the d ′ has been performed at JINR [19], [20] and at TRIUMF [21], [22], where the DCX π + + 4 He → pppp π − was measured. Unlike previous experiments, DCX on 4 He results in the production of four protons in the continuum.…”

Section: Methodsmentioning

confidence: 99%

WITHDRAWN: Resonant behaviour in double charge exchange reaction of π+-mesons on the nuclear photoemulsion

Batusov

Blokhintseva

Pontecorvo

et al. 2008

Radiation Measurements

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“…A series of experiments in search of the d ′ has been performed at JINR [19], [20] and at TRIUMF [21], [22], where the DCX π + + 4 He → pppp π − was measured. Unlike previous experiments, DCX on 4 He results in the production of four protons in the continuum.…”

Section: ′ -Resonancementioning

confidence: 99%

Resonant behaviour in double charge exchange reaction of πmesons on the nuclear photoemulsion

et al. 2006

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The invariant mass spectra of the ppπ − and pp systems produced in the double charge exchange (DCX) of positively charged pions on photoemulsion are analysed. A pronounced peak is observed in the ppπ − invariant mass spectrum, while the M pp spectrum exhibits a strong Migdal-Watson effect of the proton-proton final state interaction. These findings are in favor of the N N -decoupled N N π pseudoscalar resonance with T = 0 called d ′ . IntroductionIn this paper the spectrum is analysed of invariant masses of the ppπ − system, produced in Double Charge eXchange (DCX) reactions of π + -mesons on the nuclei 107 Ag and 109 Ag in photoemulsion; a peak has been revealed at M ppπ − ≈ 2.05 GeV. We consider this result to confirm the existence of the d ′ , that was proposed in order to explain the maxima exhibited by the forward angle DCX cross section πThe energy of the incident π + -mesons in the photoemulsion experiment was quite low: T π + = 40 ÷ 140 MeV, while the resolution in the invariant mass M ppπ − amounted *

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Total cross-section for the double charge exchange reaction $$\pi ^ + + ^4 He \to \pi ^ - + 4p$$ at 100 MeVat 100 MeV

Cited by 19 publications

References 8 publications

Inclusive pion double charge exchange inHe4at intermediate energies

Inclusive pion double charge exchange inHe4at intermediate energies

WITHDRAWN: Resonant behaviour in double charge exchange reaction of π+-mesons on the nuclear photoemulsion

Resonant behaviour in double charge exchange reaction of πmesons on the nuclear photoemulsion

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