arXiv subjects

Takaya Miyamoto

Publications and source records attributed to Takaya Miyamoto.

25 records · Page 2Linked to original sources

arXiv2017

Baryon interactions from lattice QCD with physical masses -- Overview and $S = 0, -4$ sectors --

Nuclear forces and hyperon forces are studied by lattice QCD. Simulations are performed with (almost) physical quark masses, $m_π\simeq 146$ MeV and $m_K \simeq 525$ MeV, where $N_f=2+1$ nonperturbatively ${\cal O}(a)$-improved Wilson quark action with stout smearing and Iwasaki gauge action are employed on the lattice of $(96a)^4 \simeq (8.1\mbox{fm})^4$ with $a^{-1} \simeq 2.3$ GeV. In this report, we give the overview of the theoretical framework and present the numerical results for two-nucleon forces ($S=0$) and two-$Ξ$ forces ($S=-4$). Central forces are studied in $^1S_0$ channel, and central and tensor forces are obtained in $^3S_1$-$^3D_1$ coupled channel analysis.

hep-lat↗

arXiv2017

Baryon interactions from lattice QCD with physical masses -- $S=-2$ sector --

The strangeness $S=-2$ baryon-baryon interaction is investigated directly from the fundamental theory of the strong interaction, QCD. The HAL QCD method enables us to extract baryon interactions from the Nambu-Bethe-Salpeter wave functions without using any experimental information. We present our latest result on the $S = -2$ baryon interactions and discuss the H-dibaryon state using potentials which are calculated by using the (almost) physical point gauge configurations with large lattice volume of$(8.1{\rm{fm}})^4$ generated on the K-computer.

hep-lat↗

arXiv2017

Baryon interactions from lattice QCD with physical masses ---S=-3 sector: XiSigma and XiLambda-XiSigma---

We present lattice QCD results of baryon-baryon potentials in S=-3 sector, i.e., ΞΣ(I=3/2) potentials and ΞΛ-ΞΣcoupled channel potentials (I=1/2) by using the 2+1 flavor gauge configurations with almost the physical quark masses generated on 96^4 lattice with 1/a \simeq 2.3 GeV and L = 96a \simeq 8.1 fm where m_pi \simeq 146 MeV and m_K \simeq 525 MeV. These potentials are obtained based on the time-dependent HAL QCD method with a non-relativistic approximation. Qualitative behaviors of the results are found to be consistent with those in the flavor SU(3) limit.

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arXiv2016

Towards Lattice QCD Baryon Forces at the Physical Point: First Results

Lattice QCD calculations of baryon forces are performed for the first time with (almost) physical quark masses. $N_f = 2+1$ dynamical clover fermion gauge configurations are generated at the lattice spacing of $a \simeq 0.085$ fm on a $(96 a)^4 \simeq (8.2 {\rm fm})^4$ lattice with quark masses corresponding to $(m_π, m_K) \simeq (146, 525)$ MeV. Baryon forces are calculated using the time-dependent HAL QCD method. In this report, we study $ΞΞ$ and $NN$ systems both in $^1S_0$ and $^3S_1$-$^3D_1$ channels, and the results for the central and tensor forces as well as phase shifts in the $ΞΞ$ $(^1S_0)$ channel are presented.

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arXiv2016

A Fast Algorithm for Lattice Hyperonic Potentials

We describe an efficient algorithm to compute a large number of baryon-baryon interactions from $NN$ to $ΞΞ$ by means of HAL QCD method, which lays the groundwork for the nearly physical point lattice QCD calculation with volume $(96a)^4\approx$($8.2$fm)$^4$. Preliminary results of $ΛN$ potential calculated with quark masses corresponding to ($m_π$,$m_{K}$)$\approx$(146,525)MeV are presented.

hep-lat↗

arXiv2016

$Λ_c-N$ interaction from lattice QCD

We investigate the s-wave $Λ_c-N$ interaction for spin singlet systems($^1S_0$) using the HAL QCD method. In our lattice QCD simulations, we employ gauge configurations generated by the PACS-CS Collaboration at $a = 0.0907(13)$ fm on a $32^3 \times 64$ lattice ($La = 2.902(42)$ fm). We employ two ensembles, one at $m_π= 700(1)$ MeV and the other at $m_π= 570(1)$ MeV to study the quark mass dependence of the $Λ_c-N$ interactions. We calculate a $^1S_0$ central potential not only for the $Λ_c-N$ system but also for $Λ-N$ system to understand the role of heavy charm quarks in $Λ_c-N$ system. We find repulsion at short distance and attraction at mid-range for both the $Λ_c-N$ and the $Λ-N$ potentials. The short range repulsion of the $Λ_c-N$ potential is smaller than that of the $Λ-N$ potential, and the attraction of the $Λ_c-N$ potential is small compared with the $Λ-N$ potential. The phase shift and scattering length calculated with these potentials show that there exist no bound state for both the $Λ_c-N$ and $Λ-N$ systems for $m_π > 570$ MeV.

hep-lat↗

arXiv2015

First results of baryon interactions from lattice QCD with physical masses (1) -- General overview and two-nucleon forces --

We present the lattice QCD studies for baryon-baryon interactions for the first time with (almost) physical quark masses. $N_f = 2+1$ gauge configurations are generated with the Iwasaki gauge action and nonperturbatively $O(a)$-improved Wilson quark action with stout smearing on the lattice of $(96 a)^4 \simeq (8.2 {\rm fm})^4$ with $a \simeq 0.085$ fm, where $m_π\simeq 146$ MeV and $m_K \simeq 525$ MeV. Baryon forces are calculated from Nambu-Bethe-Salpeter (NBS) correlation functions using the time-dependent HAL QCD method. In this report, we first give the general overview of the theoretical frameworks essential to the physical point calculation of baryon forces. We then present the numerical results for the two-nucleon central and tensor forces in $^3S_1$-$^3D_1$ coupled channel and the central force in $^1S_0$ channel. In particular, a clear signal is obtained for the tensor force.

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