Energy dependence of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">He</mml:mi><mml:mo>(</mml:mo><mml:mrow><mml:msup><mml:mrow><mml:mi>π</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow><mml:mo>,</mml:mo><mml:mrow><mml:msup><mml:mrow><mml:mi>π</mml:mi></mml:mrow><mml:mrow><mml:mi>−</mml:mi></mml:mrow></mml:msup></mml:mrow><mml

Gräter, J.; Bilger, R.; Clement, H.; Meier, R.; Wagner, G. J.; Friedman, E.; Schepkin, M.; Amaudruz, P.; Felawka, L.; Ottewell, D.; Smith, G. R.; Ambardar, A.; Kermani, M.; Tagliente, G.; Bonutti, Faustino; Camerini, P.; Grion, N.; Rui, R.; Peng, Hong; Mathie, E. L.; Tacik, R.; Clark, J. L.; Sevior, M. E.; Патаракин, О.О.

doi:10.1103/physrevc.58.1576

Cited by 20 publications

(20 citation statements)

References 32 publications

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“…With regard to d this means that it no longer can be formed off-shell in the presence of A -2 nucleons, but only produced on-shell associatedly with the simultaneous release of spectator nucleons into the continuum -with the consequence that the d signature in this now inclusive DCX measurements will be much less pronounced. Nevertheless, detailed DCX continuum measurements have been carried out on 3 He [231] and 4 He [232,233,234], but the results finally were inconclusive on the question of d , since it turned out that the initially assumed small spreading width was strongly underestimated [235]. With the more realistic spreading width the d effect in these measurements got too small to be uniquely identified.…”

Section: Yet Another Dibaryon Candidate: D (2065)mentioning

confidence: 99%

On the history of dibaryons and their final observation

Clement¹

2017

Progress in Particle and Nuclear Physics

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125

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Section: Yet Another Dibaryon Candidate: D (2065)mentioning

confidence: 99%

On the history of dibaryons and their final observation

Clement¹

2017

Progress in Particle and Nuclear Physics

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131

125

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“…Total and differential cross sections and pion momentum distributions have been measured at six energies in the 70-130 MeV range using the CHAOS detector at TRIUMF [16].…”

Section: Previous Experimental Workmentioning

confidence: 99%

“…One spectrum was a re-measurement of the spectrum reported by Kaufman et al[3] at 140 MeV, and confirmed that the normalization of the older data was incorrect (too small) by a factor of 100, as had been suspected. Six additional spectrawere measured with pions at the two higher incident energies, and one spectrum for the 4 He(π − , π + ) reaction was observed at 295 MeV incident energy.Total and differential cross sections and pion momentum distributions have been measured at six energies in the 70-130 MeV range using the CHAOS detector at TRIUMF [16].Some evidence for a d ′ dibaryon state of mass 2.06 GeV is claimed to be found in the energy dependence of the total DCX cross section.An extensive study of the 3 He(π − , π + ) reaction [12] in the incident energy range 120 -240 MeV was carried out with the same apparatus as that used in the experiment reported in this paper. The 3 He data, with good statistical accuracy and complete coverage of the outgoing pion energy spectrum, revealed a double-peaked structure at forward angles [12].…”

mentioning

confidence: 99%

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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“…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%

“…However, the total cross section for 4 He as a function of the initial energy exhibits a knee-like behaviour, which cannot be reproduced within conventional approaches. The said measurements were performed using liquid 4 He [21]; the use of a gas target [22] permitted to measure the invariant mass of the ppπ − system. The small statistic and low sensitivity to charged particles with energies below 5 ÷ 7 MeV, however, reduces the significance of this exclusive measurement.…”

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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Energy dependence of the4He(π+,π−

Cited by 20 publications

References 32 publications

On the history of dibaryons and their final observation

On the history of dibaryons and their final observation

Inclusive pion double charge exchange inHe4at intermediate energies

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

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