Suppression of nucleon resonances in the total photoabsorption on nuclei

Kondratyuk, L.A.; Krivoruchenko, M. I.; Bianchi, N.; Sanctis, E. De; Muccifora, V.

doi:10.1016/0375-9474(94)90918-0

Cited by 55 publications

(68 citation statements)

References 26 publications

(62 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A broadening of the excitation function due to nuclear Fermi motion certainly contributes, but cannot explain the full effect. Kondratyuk et al [12] and Alberico et al [13] have argued for an in-medium width of the relevant nucleon resonances, in particular the D 13 (1520), on the order of 300 MeV, i.e. a factor of two broader than for the free nucleon.…”

Section: Introductionmentioning

confidence: 99%

Surface and volume effects in the photoabsorption of nuclei

et al. 2004

View full text Add to dashboard Cite

Abstract. Recent experimental results for meson photoproduction from nuclei obtained with TAPS at MAMI are analyzed in view of the suppression of the second nucleon resonance region in total photoabsorption. The cross sections can be split into a component from the low density surface region of nuclei and a component which scales more like the nuclear volume. The energy dependence of the surface component is similar to the deuteron cross section, it shows a clear signal for the second resonance peak assigned to the excitation of the P11(1440), D13(1520), and S11(1535). The volume component behaves differently, it is lacking the second resonance peak and shows an enhancement at intermediate photon energies.

show abstract

Section: Introductionmentioning

confidence: 99%

Surface and volume effects in the photoabsorption of nuclei

et al. 2004

View full text Add to dashboard Cite

show abstract

“…[21] discarded as explicit states (for propagation) in HSD; they are supposed to "melt" in the nuclear medium even at normal nuclear density (see e.g. [43,44]). The argument here is that the resonance structure (above the ∆-peak) is not seen experimentally even in photoabsorption on light nuclei [45].…”

Section: Transport Models -Urqmd and Hsdmentioning

confidence: 99%

Hadronic observables at relativistic energies: Anything strange with strangeness?

et al. 2003

View full text Add to dashboard Cite

We calculate p, π ± , K ± and Λ(+Σ 0 ) rapidity distributions and compare to experimental data from SIS to SPS energies within the UrQMD and HSD transport approaches that are both based on string, quark, diquark (q,q, qq,qq) and hadronic degrees of freedom. The two transport models do not include any explicit phase transition to a quark-gluon plasma (QGP).It is found that both approaches agree rather well with each other and with the experimental rapidity distributions for protons, Λ's, π ± and K ± . Inspite of this apparent agreement both transport models fail to reproduce the maximum in the excitation function for the ratio K + /π + found experimentally between 11 and 40 A·GeV. A comparison to the various experimental data shows that this 'failure' is dominantly due to an insufficient descrip- * Supported by DFG 1 tion of pion rapidity distributions rather than missing 'strangeness'. The modest differences in the transport model results -on the other hand -can be attributed to different implementations of string formation and fragmentation, that are not sufficiently controlled by experimental data for the 'elementary' reactions in vacuum.

show abstract

“…Kondratyuk et al [2] and Alberico et al [3] have shown that this disappearance can be explained by an extra in-medium width of about 0.3 GeV for the higher resonances. Two reasons for this large width have been discussed.…”

mentioning

confidence: 99%

“…A lowering of the ρ meson strength has been predicted by various hadronic models and QCD sum rule analyses (for a summary and review see [6]). Also effects of collisional broadening of this resonance due to collisions with other baryons have been considered [2][3][4]. Both effects lead in lowest order in the density to an extra in-medium resonance width that is proportional to the nuclear density ρ [4,5,7].…”

mentioning

confidence: 99%

In-medium broadening of nucleon resonances

Lehr

Mosel

2001

Phys. Rev. C

View full text Add to dashboard Cite

We analyze the effects of an in-medium broadening of nucleon resonances on the exclusive photoproduction of mesons on nuclei as well as on the total photoabsorption cross sections in a transport calculation. We show that the resonance widths observed in semi-inclusive photoproduction on nuclei are insensitive to an in-medium broadening of nucleon resonances. This is due to a simple effect: the sizeable width of the nuclear surface and Fermi motion.PACS numbers: 25.20.Lj, 25.20.x One of the most obvious in-medium effects is the observed disappearance of the resonance structures in the second and third resonance region in the total photoabsorption cross section on nuclei [1]. Kondratyuk et al.[2] and Alberico et al. [3] have shown that this disappearance can be explained by an extra in-medium width of about 0.3 GeV for the higher resonances. Two reasons for this large width have been discussed. In [4,5] we have pointed out that the total in-medium width of the D 13 (1520) resonance could reflect a lowering of the ρ meson spectral strength. A lowering of the ρ meson strength has been predicted by various hadronic models and QCD sum rule analyses (for a summary and review see [6]). Also effects of collisional broadening of this resonance due to collisions with other baryons have been considered [2][3][4]. Both effects lead in lowest order in the density to an extra in-medium resonance width that is proportional to the nuclear density ρ [4,5,7].In a recent paper Krusche et al.[8] discuss their data on inclusive and semi-inclusive single π 0 production in the second resonance region. After subtracting a smooth background from the observed cross section these authors obtain a resonance contribution which they attribute to the D 13 (1520) nucleon excitation. This resonant part shows a width that is compatible with the free width of the D 13 (1520) when smeared over the Fermi momentum of the nucleons in the target nucleus (see Fig. 5 in [8]). This result seems to present a problem for explanations of the disappearance of this resonance in the photoabsorption experiments [1] in terms of an in-medium broadening of the D 13 resonance. Raising this problem has been the *

show abstract

Suppression of nucleon resonances in the total photoabsorption on nuclei

Cited by 55 publications

References 26 publications

Surface and volume effects in the photoabsorption of nuclei

Surface and volume effects in the photoabsorption of nuclei

Hadronic observables at relativistic energies: Anything strange with strangeness?

In-medium broadening of nucleon resonances

Contact Info

Product

Resources

About