347 research outputs found

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

    Get PDF
    We present the latest lattice QCD results for baryon interactions obtained at nearly physical quark masses. Nf=2+1N_f = 2+1 nonperturbatively O(a){\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 a12.3a^{-1} \simeq 2.3 GeV, where mπ146m_\pi \simeq 146 MeV and mK525m_K \simeq 525 MeV. In this report, we study the two-nucleon systems and two-Ξ\Xi systems in 1S0^1S_0 channel and 3S1^3S_1-3D1^3D_1 coupled channel, and extract central and tensor interactions by the HAL QCD method. We also present the results for the NΩN\Omega interaction in 5S2^5S_2 channel which is relevant to the NΩN\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

    Most Strange Dibaryon from Lattice QCD

    Get PDF
    The ΩΩ\Omega\Omega system in the 1S0^1S_0 channel (the most strange dibaryon) is studied on the basis of the (2+1)-flavor lattice QCD simulations with a large volume (8.1 fm)3^3 and nearly physical pion mass mπ146m_{\pi}\simeq 146 MeV at a lattice spacing a0.0846a\simeq 0.0846 fm. We show that lattice QCD data analysis by the HAL QCD method leads to the scattering length a0=4.6(6)(0.5+1.2)fma_0 = 4.6 (6)(^{+1.2}_{-0.5}) {\rm fm}, the effective range reff=1.27(3)(0.03+0.06)fmr_{\rm eff} = 1.27 (3)(^{+0.06}_{-0.03}) {\rm fm} and the binding energy BΩΩ=1.6(6)(0.6+0.7)MeVB_{\Omega \Omega} = 1.6 (6) (^{+0.7}_{-0.6}) {\rm MeV}. These results indicate that the ΩΩ\Omega\Omega system has an overall attraction and is located near the unitary regime. Such a system can be best searched experimentally by the pair-momentum correlation in relativistic heavy-ion collisions.Comment: 6 pages and 4 figure

    NΩN\Omega dibaryon from lattice QCD near the physical point

    Get PDF
    The nucleon(NN)-Omega(Ω\Omega) system in the S-wave and spin-2 channel (5^5S2_2) is studied from the (2+1)-flavor lattice QCD with nearly physical quark masses (mπ146m_\pi \simeq 146~MeV and mK525m_K \simeq 525~MeV). 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 NΩN\Omega(5^5S2_2) 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)a_0= 5.30(0.44)(^{+0.16}_{-0.01})~fm, reff=1.26(0.01)(0.01+0.02)r_{\rm eff} = 1.26(0.01)(^{+0.02}_{-0.01})~fm, B=1.54(0.30)(0.10+0.04)B = 1.54(0.30)(^{+0.04}_{-0.10})~MeV, respectively. Including the extra Coulomb attraction, the binding energy of pΩp\Omega^-(5^5S2_2) becomes BpΩ=2.46(0.34)(0.11+0.04)B_{p\Omega^-} = 2.46(0.34)(^{+0.04}_{-0.11})~MeV. Such a spin-2 pΩp\Omega^- state could be searched through two-particle correlations in pp-pp, pp-nucleus and nucleus-nucleus collisions.Comment: 16 pages, 6 figures, a reference adde

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

    Full text link
    Lattice QCD calculations of baryon forces are performed for the first time with (almost) physical quark masses. Nf=2+1N_f = 2+1 dynamical clover fermion gauge configurations are generated at the lattice spacing of a0.085a \simeq 0.085 fm on a (96a)4(8.2fm)4(96 a)^4 \simeq (8.2 {\rm fm})^4 lattice with quark masses corresponding to (mπ,mK)(146,525)(m_\pi, m_K) \simeq (146, 525) MeV. Baryon forces are calculated using the time-dependent HAL QCD method. In this report, we study ΞΞ\Xi\Xi and NNNN systems both in 1S0^1S_0 and 3S1^3S_1-3D1^3D_1 channels, and the results for the central and tensor forces as well as phase shifts in the ΞΞ\Xi\Xi (1S0)(^1S_0) channel are presented.Comment: Talk given at the 12th International Conference on Hypernuclear and Strange Particle Physics (HYP2015), Sendai, Japan, 7-12 Sep 2015, 4 pages, 6 figure

    Tumor Suppressor Gene-Based Nanotherapy: From Test Tube to the Clinic

    Get PDF
    Cancer is a major health problem in the world. Advances made in cancer therapy have improved the survival of patients in certain types of cancer. However, the overall five-year survival has not significantly improved in the majority of cancer types. Major challenges encountered in having effective cancer therapy are development of drug resistance by the tumor cells, nonspecific cytotoxicity, and inability to affect metastatic tumors by the chemodrugs. Overcoming these challenges requires development and testing of novel therapies. One attractive cancer therapeutic approach is cancer gene therapy. Several laboratories including the authors' laboratory have been investigating nonviral formulations for delivering therapeutic genes as a mode for effective cancer therapy. In this paper the authors will summarize their experience in the development and testing of a cationic lipid-based nanocarrier formulation and the results from their preclinical studies leading to a Phase I clinical trial for nonsmall cell lung cancer. Their nanocarrier formulation containing therapeutic genes such as tumor suppressor genes when administered intravenously effectively controls metastatic tumor growth. Additional Phase I clinical trials based on the results of their nanocarrier formulation have been initiated or proposed for treatment of cancer of the breast, ovary, pancreas, and metastatic melanoma, and will be discussed

    Hydrogen-bond-assisted isotactic-specific radical polymerization of N-vinyl-2-pyrrolidone with tartrate additives in toluene at low temperatures : high-resolution 1H NMR analysis

    Get PDF
    A diethyl L-tartrate (L-EtTar)-assisted radical polymerization of N-vinyl-2-pyrrolidone has been developed as the first reported example of the synthesis of isotactic-rich poly(N-vinyl-2-pyrrolidone) (PVP). The addition of L-EtTar in toluene at temperatures of –40°C and lower led to a significant increase in the polymer yield by one order of magnitude compared with the reaction in the absence of L-EtTar. Decreasing the polymerization temperature led to increases in the isotacticity of the PVP, with the mm triad reaching 66.4% at −93 °C. 1H NMR measurement at 920 MHz was conducted to establish a reliable strategy for quantifying the triad tacticities. High-temperature NMR measurements at 250 °C were performed using a specially-designed NMR probe, which led to dramatic narrowing of the 1H line width
    corecore