日本大学井上貴史氏のセミナーを下記の予定で行います。皆様、奮ってご参加ください。

Lecturer: Prof. Takashi Inoue (Nihon University)
Title: Nuclear force from QCD on lattice and its application
Date: February 8, 2017 (Wed) 16:00 - 17:00
Place: Room 907, Faculty of Science Building 1, Hongo, Univ. Tokyo

abstract:
Explaining or predicting properties of nuclei starting from QCD is one of the most challenging problems in physics. There are several attempts to extract ground state energy of nuclei in lattice QCD simulations, however it turned out that direct extraction is practically impossible due to small energy splittings between states. We adopt an alternative approach to study nuclei starting from QCD. Our strategy consists of two stages. First, we extract two-nucleon interaction from QCD by means of the HAL QCD method. Namely, we carry out lattice QCD numerical simulation with six quarks, and measure the so called baryon four point correlation function, and construct potential of the baryon interaction through the equation which the function satisfy. Then, we apply the potential to modern methods for few-body system or established many-body theories for nuclei.

In order to derive general baryon-baryon interactions including nuclear force in the physical world, now we are performing lattice QCD simulation with almost physical quarks. However, we need more time to finish our calculation. Therefore, this time, we use NN potential from lattice QCD at unphysically large u and d quark mass, e.g. corresponding to a pseudo-scalar meson mass 469 MeV and a nucleon mass 1161 MeV. Obtained NN potentials posses common features of phenomenological ones, although their strength are weaker than reality. Namely, they have strong repulsion at short distance, attraction at medium and long distance, and strong tensor force. Accordingly, the potentials reproduce experimental data of NN scattering qualitatively. With these NN potentials in the unphysical hadron worlds, we study doubly closed nuclei 4He, 16O, and 40Ca, and infinite matter. We find that these nuclei are bound at pseudo-scalar meson mass 469 MeV.

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This seminar is supported by "Priority Issue 9 to be Tackled by Using Post K Computer".

Contact person: Noritaka Shimizu and Takaharu Otsuka
(shimizu@cns.s.u-tokyo.ac.jp)