Hadron-hadron potentials coupled to quark degrees of freedom for X(3872)

To study the internal structure of the exotic hadron $X(3872)$, considering the coupled-channel potential between quarks and hadrons is necessary because $X(3872)$ is regarded as a mixture state of $c\bar{c}$ and $D^0\bar{D}^{*0}$. In this work, we construct the hadron-hadron potentials coupled to the quark channel and study the properties of the $D^0\bar{D}^{*0}$ potentials for $X(3872)$. In particular, we compare various local approximations by focusing on the scattering phase shifts.Comment: 4 pages, 2 figures, proceedings of 17th International Workshop on Meson Physics (MESON2023), June 22nd to 27th, 202

Growth of self-integrated atomic quantum wires and junctions of a Mott semiconductor

1ナノメートル半導体量子細線の作製に成功 --量子の熱帯魚パターンが拓く未来のナノテク--. 京都大学プレスリリース. 2023-05-08.Continued advances in quantum technologies rely on producing nanometer-scale wires. Although several state-of-the-art nanolithographic technologies and bottom-up synthesis processes have been used to engineer these wires, critical challenges remain in growing uniform atomic-scale crystalline wires and constructing their network structures. Here, we discover a simple method to fabricate atomic-scale wires with various arrangements, including stripes, X-junctions, Y-junctions, and nanorings. Single-crystalline atomic-scale wires of a Mott insulator, whose bandgap is comparable to those of wide-gap semiconductors, are spontaneously grown on graphite substrates by pulsed-laser deposition. These wires are one unit cell thick and have an exact width of two and four unit cells (1.4 and 2.8 nm) and lengths up to a few micrometers. We show that the nonequilibrium reaction-diffusion processes may play an essential role in atomic pattern formation. Our findings offer a previously unknown perspective on the nonequilibrium self-organization phenomena on an atomic scale, paving a unique way for the quantum architecture of nano-network

Analysis of coupled-channel potentials with quark and hadron degrees of freedom

The quark-antiquark potentials are known to be confining in the absence of the q̅q pair creation. On the other hand, the inter-hadron potentials vanish at large distance, because the interaction range is limited by the inverse pion mass. When the q̅q pair creation and annihilation are switched on, the channel coupling occurs between the quark and hadron degrees of freedom, modifying the behavior of potentials. In this work, we investigate the properties of the effective potentials obtained by eliminating one of the channels. We show that the coupling to the eliminated channel induces a non-local and energy dependent effective potential, irrespective of the properties of the transition potential. In addition, when the hadron channel having continuous scattering eigenstates is eliminated, the resulting inter-quark potential contains an imaginary part above the threshold to describe the decay effect into the meson pair