arXiv subjects

Daisuke Fujii

Publications and source records attributed to Daisuke Fujii.

20 records · Page 2Linked to original sources

arXiv2021

Decay properties of Roper resonance in the holographic QCD

We investigate the one pion decay of the Roper resonance $N^*(1440)$$\to$$N$$π$ in the Sakai-Sugimoto model of the holographic QCD. The nucleon and Roper resonance emerge as ground and first excited states of the collective radial motion of the instanton in the four dimensional space with one extra dimension. It is found that the ratio of the $π$$NN^*$ and $π$$NN$ couplings, and hence the ratio of $g_A^{NN^*}$ and $g_A^{NN}$, is well reproduced in comparison with the experimental data. The mechanism of this result is due to the collective nature of excitations, which is very different from that of the single particle nature of the constituent quark model. Our results are obtained in the large-$N_c$ and large $λ$ ('t~Hooft coupling) limit which are useful to test how baryon resonances share what are expected in these limits.

hep-ph↗

arXiv2020

Heavy baryons in holographic QCD with higher dimensional degrees of freedom

We try to introduce heavy flavors to Sakai-Sugimoto model by regarding higher dimensional components of gauge fields as heavy mesons. Using the Forgács and Manton approach, we obtain a theory composed of heavy mesons and the instanton of light flavors. Applying the collective coordinate quantization method, we derived a mass formula of heavy baryons. In the leading order of $1/m_{H}$ expansion ($m_{H}$ the mass of a heavy quark), we find singlet and doublet states in the heavy quark symmetry (HQS). Also, we obtain the degenerate Roper like and odd parity excitations. By virtue of heavy meson degrees of freedom, our mass formula reproduces the mass ordering of $Σ^*_c$ and $Λ_c^*$ correctly.

hep-ph↗