NΩ dibaryon from lattice QCD near the physical point

Takumi Iritani,Sinya Aoki,Takumi Doi,Faisal Etminan,Shinya Gongyo,Tetsuo Hatsuda,Yoichi Ikeda,Takashi Inoue,Noriyoshi Ishii,Takaya Miyamoto,Kenji Sasaki

doi:10.1016/j.physletb.2019.03.050

Abstract

The nucleon(N)-Omega(Ω) system in the S-wave and spin-2 channel (S25) is studied from the (2+1)-flavor lattice QCD with nearly physical quark masses (mπ≃146MeV and mK≃525MeV). The time-dependent HAL QCD method is employed to convert the lattice QCD data of the two-baryon correlation function to the baryon-baryon potential and eventually to the scattering observables. The NΩ(S25) potential, obtained under the assumption that its couplings to the D-wave octet-baryon pairs are small, is found to be attractive in all distances and to produce a quasi-bound state near unitarity: In this channel, the scattering length, the effective range and the binding energy from QCD alone read a0=5.30(0.44)(−0.01+0.16)fm, reff=1.26(0.01)(−0.01+0.02)fm, B=1.54(0.30)(−0.10+0.04)MeV, respectively. Including the extra Coulomb attraction, the binding energy of pΩ−(S25) becomes BpΩ−=2.46(0.34)(−0.11+0.04)MeV. Such a spin-2 pΩ− state could be searched through two-particle correlations in p-p, p-nucleus and nucleus-nucleus collisions.

Highlights

Quest for dibaryons is a long-standing experimental and theoretical challenge in hadron physics [1,2]
Each term in the r.h.s. receives t-dependence which provides “signal” instead of “noise” for V C (r ). (If there remains residual t-dependence in V C (r ), it implies the necessity of the next-to-leading order of the derivative expansion and/or the channel coupling to other states [23,24].) This is why the data at moderate values of t ∼ 1 fm are sufficient to extract the baryonbaryon interaction in HAL QCD method
We have studied the N- system in the 5 S2 channel, which is one of the promising candidates for quasi-stable dibaryon, from the (2+1)-flavor lattice QCD simulations with nearly physical quark masses

Summary

Introduction

Quest for dibaryons is a long-standing experimental and theoretical challenge in hadron physics [1,2]. Among various theoretical attempts to study dibaryons, one of the recent highlights is the (2+1)-flavor lattice QCD simulations near the physical point (mπ 146 MeV and m K 525 MeV) by HAL QCD Collaboration. The possible diOmega (), originally proposed by the Skyrme model [6], has recently been examined in detail from the same lattice QCD data [7]. Another interesting candidate of the dibaryon is N (uudsss or uddsss) in the 5 S2 channel. The purpose of this Letter is to study N (5 S2 ) on the basis of realistic (2+1)-flavor lattice QCD simulations near the physical point (mπ 146 MeV and m K 525 MeV).

HAL QCD method

Lattice setup

Spin-2 N potential

Summary