Study of the Δ isobar excitation in nuclei with the (3He,t) reaction

Contardo, D.; Bedjidian, M.; Grossiord, J. Y.; Guichard, A.; Haroutunian, R.; Pizzi, J.R.; Ellegaard, C.; Gaarde, C.; Larsen, J.S.; Goodman, C.D.; Bergqvist, I.; Brockstedt, A.; Carlén, L.; Ekström, Peter; Bachelier, D.; Boyard, J. L.; Hennino, T.; Jourdain, J.C.; Roy‐Stéphan, M.; Boivin, M.; Radvanyi, P.

doi:10.1016/0370-2693(86)91639-4

Cited by 120 publications

(44 citation statements)

References 9 publications

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“…The modification of the ∆(1232)-peak has been also seen in the measured ejectile energy distribution spectrum in the inclusive ( 3 He, t) reaction on the nucleus relative to proton [6]. This phenomenon is also found in other inclusive reactions, e.g., (p, n) [7].…”

Section: Introductionsupporting

confidence: 59%

Modification of {$\mit \Delta $}(1232) in the Neutrino Nucleus Reaction

Das¹

2017

Acta Phys. Pol. B

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The remarkable observations in the pion induced and charge exchange reactions on a nucleus are the significant shift and broadening of the ∆(1232)-peak relative to free pion nucleon scattering. For the forward going massless leptons, the weak process (ν l , l) on a nucleon, according to Adler's partially conserved axial current theorem, is connected to the pion nucleon scattering. This mechanism is also applicable to the nucleus. Therefore, the modification of the ∆-peak in a nucleus can be seen in the (ν l , l) reaction since it is connected to the pion nucleus scattering. To investigate this issue quantitatively, the double differential cross sections of the forward going ejectile l energy distribution in the (ν l , l) reaction are calculated in the ∆-excitation region for both proton and nucleus. The measured pion nucleon and pion nucleus scattering cross sections in the quoted energy region are used in these reactions as input. Since the (ν l , l) reaction is connected to the pion induced scattering, the features of the previous reaction is shown analogous to those of the later.

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Section: Introductionsupporting

confidence: 59%

Modification of {$\mit \Delta $}(1232) in the Neutrino Nucleus Reaction

Das¹

2017

Acta Phys. Pol. B

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“…The basic mechanism is linked to the nuclear collective pionic modes sometimes called pisobars originating from the p-wave coupling of the pion to delta-holes states. According to detailed calculation [2,3] these collective modes are needed to explain charge exchange data [4,5], despite the peripheral character of these experiments. This medium effect yields a softening of the pion dispersion relation and consequently a modification of the twopion propagator involved in the unitarized T matrix describing pion-pion interaction at finite density.…”

Section: Introductionmentioning

confidence: 99%

Medium modification of the pion-pion interaction at finite density

2000

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We discuss medium modifications of the unitarized pion-pion interaction in the nuclear medium. We incorporate both the effects of chiral symmetry restoration and the influence of collective nuclear pionic modes originating from the p-wave coupling of the pion to delta-hole configurations. We show in particular that the dropping of the sigma meson mass significantly enhances the low energy structure created by the in-medium collective pionic modes.

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“…The position of the Δ peak is shifted towards a low excitation energy by ∼ 65 MeV, becoming insensitive to targets with mass number A ≥ 12. As said in the introduction, this shift was already observed on isobaric chargeexchange reactions with lighter nuclei [1][2][3][4][5], and its origin was the subject of intense debate (see e.g., Refs. [7][8][9][10] and references therein).…”

Section: Resultsmentioning

confidence: 99%

“…The excitation of the Δ(1232) in (p, n) and ( 3 He,t) reactions was extensively studied in the 1980's [1][2][3][4][5]. A experimental program completely devoted to study the excitation of this resonance in reactions with light and medium mass projectiles was performed at the SATURNE accelerator in Saclay during those years [6].…”

Section: Introductionmentioning

confidence: 99%

Excitation of Δ andN^*resonances in isobaric charge-exchange reactions of heavy nuclei

Vidaña

Benlliure

Geißel

et al. 2016

EPJ Web of Conferences

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Abstract. We present a model for the study of the excitation of Δ(1232) and N * (1440) resonances in isobaric charge-exchange ( A Z, A (Z ± 1)) reactions of heavy nuclei. Quasi-elastic and inelastic elementary processes contributing to the double differential cross sections of the reactions are described in terms of the exchange of virtual pions. The inelastic channel includes processes where the resonances are excited both in the target and in the projectile nucleus. We present results for reactions of 112 Sn and 124 Sn on different targets. Our results confirm that the position of the Δ peak is insensitive to targets with mass number A ≥ 12, and show that the origin of the Δ peak shift towards low excitation energies, with respect to its position in reactions with a proton target, can be easily explained in terms of the superposition of the different excitation mechanisms contributing to the reaction.

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Study of the Δ isobar excitation in nuclei with the (3He,t) reaction

Cited by 120 publications

References 9 publications

Modification of {$\mit \Delta $}(1232) in the Neutrino Nucleus Reaction

Modification of {$\mit \Delta $}(1232) in the Neutrino Nucleus Reaction

Medium modification of the pion-pion interaction at finite density

Excitation of Δ andN^*resonances in isobaric charge-exchange reactions of heavy nuclei

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Study of the Δ isobar excitation in nuclei with the (3He,t) reaction

Cited by 120 publications

References 9 publications

Modification of {$\mit \Delta $}(1232) in the Neutrino Nucleus Reaction

Modification of {$\mit \Delta $}(1232) in the Neutrino Nucleus Reaction

Medium modification of the pion-pion interaction at finite density

Excitation of Δ andN*resonances in isobaric charge-exchange reactions of heavy nuclei

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Excitation of Δ andN^*resonances in isobaric charge-exchange reactions of heavy nuclei