1. Current understanding of the nuclear force
Hiroyuki Kamano
Lunch Seminar, July 4
& Symposium for Centennial Celebration of Hideki Yukawa (June 3)
Impact and contribution of Yukawa’s meson theory
to the modern nuclear physics were mentioned.

2. Repulsive Attractive core
W. Weise “Overview and perspectives in Nuclear Physics” : Plenary talk in INPC2007
< 1 fm
~1-2 fm
2 fm <
Repulsive
core
Attractive
Treatment of quark-gluon d.o.f.
will be inevitable!
or heavy meson
(r, w, s …) exchange
phenomenological approach

3. “Nuclear Force from Lattice QCD”
by N. Ishii, S. Aoki, T. Hatsuda, to be published in PRL this week.
First successful calculation of the nuclear force from quark-gluon d.o.f. .
Review article by Prof. F. Wilczek
NN potential:
Nature 445,157 (2007)
Strategy
1. Calculate the (s-wave projected) NN wave
function using the Lattice QCD simulations.
Obtain the central NN potential at each
fixed E from the relation:
( : s-wave projected NN w.f.; : reduced mass)
Several articles for this research
also appeared in newspapers June 21.
⇒ Calculated using “Blue Gene/L” at KEK

4. Lattice QCD result of the NN central potential
pure Vc
Lattice QCD
Yukawa’s theory
(1p exchange)
“effective” Vc
= pure Vc + DVc
coupling effect
with 3D1 state.
Lattice QCD captures the essential features of the NN potential in all region!
Yukawa’s result (long distance)
Repulsive core (short distance)

5. Summary and Perspectives
Further improvements are needed for the quantitative estimations:
-　Include the virtual pair contribution
　 (non-quenched calculation)
- Use the physical mass.
Calculation of other components of the NN potential (LS, tensor etc.)
Investigation of physical origin of the repulsive core.
Application to (“prediction” of) Nucleon-Hyperon1) and Hyperon-Hyperon potentials.
⇔ Interpretation of
Yukawa’s theory:
Which contributions and/or mechanisms
are responsible for the repulsive core?
Closely related to the experimental research of hypernuclei at J-PARC2)
1) Hyperon = Baryon with “strangeness”
2) J-PARC = Japan Proton Accelerator Research Complex