arXiv subjects

T. Takaki

Publications and source records attributed to T. Takaki.

4 recordsLinked to original sources

arXiv2003

$π$NN coupling and two-pion photoproduction on the nucleon

Effects of non-resonant photoproductions arising from two different $πNN$ couplings are investigated in the $γN\toππN$ reaction. We find that the pseudoscalar (PS) $πNN$ coupling is generally preferable to the pseudovector (PV) $πNN$ coupling and particularly the total cross sections are successfully described by the model with the PS $πNN$ coupling. In order to see the difference between the two couplings, we also show the results of invariant mass spectra and helicity-dependent cross sections in various isospin channels calculated with the PS and PV couplings.

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arXiv2001

Nuclear Photoabsorption at Photon Energies between 300 and 850 Mev

We construct the formula for the photonuclear total absorption cross section using the projection method and the unitarity relation. Our treatment is very effective when interference effects in the absorption processes on a nucleon are strong. The disappearance of the peak around the position of the $D_{13}$ resonance in the nuclear photoabsorption can be explained with the cooperative effect of the interference in two-pion production processes,the Fermi motion, the collision broadenings of $Δ$ and $N^*$, and the pion distortion in the nuclear medium. The change of the interference effect by the medium plays an important role.

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arXiv1998

Cooperative damping mechanism of the resonance in the nuclear photoabsorption

We propose a resonance damping mechanism to explain the disappearance of the peaks around the position of the resonances higher than the $Δ$ resonance in the nuclear photoabsorption. This phenomenon is understood by taking into account the cooperative effect of the collision broadening of $Δ$ and $N^{*}$, the pion distortion and the interference in the two-pion photoproduction processes in the nuclear medium.

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arXiv1997

Effect of $ρN$ channel in the $γN \to ππN$ reactions

A model for the two-pion photoproduction on the nucleon proposedearlier is modified to simultaneously explain the total cross sections and the invariant mass spectra. Using this model, we discuss the role of the $ρ$ meson in the $γN \to ππN$ reaction.

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