pΞ−p\Xi^- Correlation in Relativistic Heavy Ion Collisions with Nucleon-Hyperon Interaction from Lattice QCD

On the basis of the $p\Xi^-$ interaction extracted from (2+1)-flavor lattice QCD simulations at the physical point, the momentum correlation of $p$ and $\Xi^-$ produced in relativistic heavy ion collisions is evaluated. $C_{\rm SL}(Q)$ defined by a ratio of the momentum correlations between the systems with different source sizes is shown to be largely enhanced at low momentum due to the strong attraction between $p$ and $\Xi^-$ in the $I=J=0$ channel. Thus, measuring this ratio at RHIC and LHC and its comparison to the theoretical analysis will give a useful constraint on the $p\Xi^-$ interaction.Comment: 4 pages, 2 figures; proceedings contribution for Quark Matter 201

Strange Tribaryons as Nona-quark States

Strange tribaryons as nona-quark (9 quark) states is studied to describe the S=-1 resonance S^0(3115) recently discovered in the reaction K- + ^4 He -> S^0 + p. We have identified S^0(3115) as a member of the flavor 27-plet, in particular, (F_{flavor},I_{isospin},J_{spin})=(27,1,1/2) or (27,1,3/2). The color-magnetic interaction between quarks favors small multiplets in flavor and spin, which leads to a natural explanation that I=1 is the lowest state among the S=-1 tribaryons with J=1/2. Classification of the S^+ -state recently reported as well as possible locations of other light strange tribaryons such as (10*,0,3/2) with S=-1, (8,1/2,1/2) with S=-2 and (1,0,3/2) with S=-3 are also discussed.Comment: 10 pages, 3 figure

Complex Heavy-Quark Potential at Finite Temperature from Lattice QCD

We calculate for the first time the complex potential between a heavy quark and antiquark at finite temperature across the deconfinement transition in lattice QCD. The real and imaginary part of the potential at each separation distance $r$ is obtained from the spectral function of the thermal Wilson loop. We confirm the existence of an imaginary part above the critical temperature $T_C$, which grows as a function of $r$ and underscores the importance of collisions with the gluonic environment for the melting of heavy quarkonia in the quark-gluon-plasma.Comment: 4 pages, 3 figures, to be published in PR

Spectral Analysis of Excited Nucleons in Lattice QCD with Maximum Entropy Method

We study the mass spectra of excited baryons with the use of the lattice QCD simulations. We focus our attention on the problem of the level ordering between the positive-parity excited state N'(1440) (the Roper resonance) and the negative-parity excited state N^*(1535). Nearly perfect parity projection is accomplished by combining the quark propagators with periodic and anti-periodic boundary conditions in the temporal direction. Then we extract the spectral functions from the lattice data by utilizing the maximum entropy method. We observe that the masses of the N' and N^* states are close for wide range of the quark masses (M_pi=0.61-1.22 GeV), which is in contrast to the phenomenological prediction of the quark models. The role of the Wilson doublers in the baryonic spectral functions is also studied.Comment: 15 pages, 5 figures included, typos corrected, and references adde

Three-Dimensional Imaging Method Incorporating Range Points Migration and Doppler Velocity Estimation for UWB Millimeter-Wave Radar

High-resolution, short-range sensors that can be applied in optically challenging environments (e.g., in the presence of clouds, fog, and/or dark smog) are in high demand. Ultrawideband (UWB) millimeter-wave radars are one of the most promising devices for the above-mentioned applications. For target recognition using sensors, it is necessary to convert observational data into full 3-D images with both time efficiency and high accuracy. For such conversion algorithm, we have already proposed the range points migration (RPM) method. However, in the existence of multiple separated objects, this method suffers from inaccuracy and high computational cost due to dealing with many observed RPs. To address this issue, this letter introduces Doppler-based RPs clustering into the RPM method. The results from numerical simulations, assuming 140-GHz band millimeter radars, show that the addition of Doppler velocity into the RPM method results in more accurate 3-D images with reducing computational costs

Are two nucleons bound in lattice QCD for heavy quark masses? -- Consistency check with L\"uscher's finite volume formula --

On the basis of the L\"uscher's finite volume formula, a simple test (consistency check or sanity check) is introduced and applied to inspect the recent claims of the existence of the nucleon-nucleon ($NN$) bound state(s) for heavy quark masses in lattice QCD. We show that the consistency between the scattering phase shifts at $k^2 > 0$ and/or $k^2 < 0$ obtained from the lattice data and the behavior of phase shifts from the effective range expansion (ERE) around $k^2=0$ exposes the validity of the original lattice data, otherwise such information is hidden in the energy shift $\Delta E$ of the two nucleons on the lattice. We carry out this sanity check for all the lattice results in the literature claiming the existence of the $NN$ bound state(s) for heavy quark masses, and find that (i) some of the $NN$ data show clear inconsistency between the behavior of ERE at $k^2 > 0$ and that at $k^2 < 0$, (ii) some of the $NN$ data exhibit singular behavior of the low energy parameter (such as the divergent effective range) at $k^2<0$, (iii) some of the $NN$ data have the unphysical residue for the bound state pole in S-matrix, and (iv) the rest of the $NN$ data are inconsistent among themselves. Furthermore, we raise a caution of using the ERE in the case of the multiple bound states. Our finding, together with the fake plateau problem previously pointed out by the present authors, brings a serious doubt on the existence of the $NN$ bound states for pion masses heavier than 300 MeV in the previous studies.Comment: 39 pages, 16 figures, and 11 tables, title changed, references and comment adde

Baryon interactions from lattice QCD with physical quark masses -- Nuclear forces and ΞΞ\Xi\Xi forces --

We present the latest lattice QCD results for baryon interactions obtained at nearly physical quark masses. $N_f = 2+1$ 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, where $m_\pi \simeq 146$ MeV and $m_K \simeq 525$ MeV. In this report, we study the two-nucleon systems and two-$\Xi$ systems in $^1S_0$ channel and $^3S_1$-$^3D_1$ coupled channel, and extract central and tensor interactions by the HAL QCD method. We also present the results for the $N\Omega$ interaction in $^5S_2$ channel which is relevant to the $N\Omega$ pair-momentum correlation in heavy-ion collision experiments.Comment: Talk given at 35th International Symposium on Lattice Field Theory (Lattice 2017), Granada, Spain, 18-24 Jun 2017, 8 pages, 9 figures. arXiv admin note: text overlap with arXiv:1702.0160