arXiv subjects

for HAL QCD Collaboration

Publications and source records attributed to for HAL QCD Collaboration.

24 records · Page 2Linked to original sources

arXiv2011

Bound H-dibaryon from Full QCD Simulations on the Lattice

Using a new method recently proposed by the HAL QCD collaboration to study hadron interactions in lattice QCD, we investigate a possibility for an existence of the H-dibaryon in the flavor SU(3) symmetric world. A potential for the flavor-singlet baryon-baryon channel is derived from the Nambu-Bethe-Salpeter wave function, and the elusive H-dibaryon is shown to be a bound state, with the binding energy of 20--50 MeV for the pseudo-scalar meson masses in the range that 469--1171 MeV.

hep-lat↗

arXiv2011

The Lattice QCD Study of the Three-Nucleon Force

We investigate three-nucleon forces (3NF) from lattice QCD simulations, utilizing the Nambu-Bethe-Salpeter (NBS) wave function to determine two-nucleon forces (2NF) and 3NF on the same footing. Quantum numbers of the three-nucleon (3N) system are chosen to be (I, J^P)=(1/2, 1/2^+) (the triton channel). We consider the simplest geometrical configuration where 3N are aligned linearly with an equal spacing, to reduce the enormous computational cost. Lattice QCD simulations are performed using Nf=2 dynamical clover fermion configurations at the lattice spacing of a = 0.156 fm on a 16^3 x 32 lattice with a large quark mass corresponding to m(π) = 1.13 GeV. We find repulsive 3NF at short distance.

hep-lat↗

arXiv2011

Bound H-dibaryon in the Flavor SU(3) Limit from a Full QCD Simulation on the Lattice

Existence of the H-dibaryon in the flavor SU(3) symmetric limit is studied by full QCD simulations on the lattice, in the approach recently developed for the baryon-baryon (BB) interactions. Potential of the flavor-singlet BB channel is derived from the Nambu-Bethe-Salpeter wave function, and a bound H-dibaryon is discovered from it, with the binding energy of 20--50 MeV for the pseudo-scalar meson mass of 469--1171 MeV.

hep-lat↗

arXiv2011

Exploring Three Nucleon Forces in Lattice QCD

We study the three nucleon force in Nf=2 dynamical clover fermion lattice QCD, utilizing the Nambu-Bethe-Salpeter wave function of the three nucleon system. Since parity-odd two nucleon potentials are not available in lattice QCD at this moment, we develop a new formulation to extract the genuine three nucleon force which requires only the information of parity-even two nucleon potentials. In order to handle the extremely expensive calculation cost, we consider a specific three-dimensional coordinate configuration for the three nucleons. We find that the linear setup is advantageous, where nucleons are aligned linearly with equal spacings. The lattice calculation is performed with 16^3 x 32 configurations at β=1.95, m_π=1.13 GeV generated by CP-PACS Collaboration, and the result of the three nucleon force in triton channel is presented.

hep-lat↗

arXiv2010

Flavor structure of the baryon-baryon interaction from lattice QCD

We investigate baryon-baryon (BB) interactions in the 3-flavor full QCD simulations with degenerate quark masses for all flavors. The BB potentials in the orbital S-wave are extracted from the Nambu-Bethe-Salpeter wave functions measured on the lattice. We observe strong flavor-spin dependences of the BB potentials at short distances. In particular, a strong repulsive core exists in the flavor-octet and spin-singlet channel(the 8_s representation), while an attractive core appears in the flavor singlet channel (the 1 representation). We discuss the relation of such flavor-spin dependence with the Pauli exclusion principle at the quark level. The possible existence of an H-dibaryon resonance above the Lambda-Lambda threshold is also discussed.

hep-lat↗

arXiv2010

The study of the Three Nucleon Force in full QCD Lattice calculations

We study the three nucleon force in the triton channel using dynamical clover fermion lattice QCD. The Nambu-Bethe-Salpeter wave function is utilized to obtain the potentials among three nucleons. Since the straightforward calculation is prohibitively expensive, two different frameworks are developed to meet the challenge. In the first method, we study the effective two nucleon potentials in the three nucleon system, where the differences between the effective two nucleon potentials and the genuine two nucleon potentials correspond to the three nucleon system effect, part of which is originated from the three nucleon force. The calculation is performed using Nf=2 clover fermion at m(π)= 1.13GeV generated by CP-PACS Collaboration, and Nf=2+1 clover fermion at m(π)= 0.70, 0.57GeV generated by PACS-CS Collaboration. In the second method, we study the three nucleon system with 3D-configuration of nucleons fixed. This enables us to extract the three nucleon force directly, if both of parity-even and parity-odd two nucleon potentials are provided. Since parity-odd two nucleon potentials are not available in lattice QCD at this moment, we propose a new general procedure to identify the three nucleon force using only parity-even two nucleon potentials. The calculation are performed with Nf=2 clover fermion at m(π)= 1.13GeV generated by CP-PACS Collaboration, employing the linear setup for the 3D-configuration. Preliminary results for the scalar/isoscalar three nucleon force are presented.

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