Assumpta Parreno

Evidence for a bound H dibaryon from lattice QCD.

We present evidence for the existence of a bound H dibaryon, an I=0, J=0, s=-2 state with valence quark structure uuddss, at a pion mass of m(π)∼389  MeV. Using the results of lattice QCD calculations performed on four ensembles of anisotropic clover gauge-field configurations, with spatial extents of L∼2.0, 2.5, 3.0, and 3.9 fm at a spatial lattice spacing of b(s)∼0.123  fm, we find an H dibaryon bound by B(∞)(H)=16.6±2.1±4.6  MeV at a pion mass of m(π)∼389  MeV.

Hyperon–nucleon scattering from fully-dynamical lattice QCD

Abstract We present results of the first fully-dynamical lattice QCD determination of hyperon–nucleon scattering. One s-wave phase shift was determined for nΛ scattering in both spin-channels at pion masses of 350, 490 and 590 MeV, and for n Σ − scattering in both spin channels at pion masses of 490 and 590 MeV. The calculations were performed with domain-wall valence quarks on dynamical, staggered gauge configurations with a lattice spacing of b ∼ 0.125 fm .

The Deuteron and Exotic Two-Body Bound States from Lattice QCD

Results of a high-statistics, multi-volume Lattice QCD exploration of the deuteron, the di-neutron, the H-dibaryon, and the {Xi}-{Xi}- system at a pion mass of m{sub {pi}} ~ 390 MeV are presented. Calculations were performed with an anisotropic n{sub f} = 2+1 Clover discretization in four lattice volumes of spatial extent L ~ 2.0, 2.5, 3.0 and 4.0 fm, with a lattice spacing of b{sub s} ~ 0.123 fm in the spatial-direction, and b{sub t} ~ b{sub s}/3.5 in the time-direction. The {Xi}-{Xi}- is found to be bound by B{sub {Xi}-{Xi}} = 14.0(1.4)(6.7) MeV, consistent with expectations based upon phenomenological models and low-energy effective field theories constrained by nucleon-nucleon and hyperon-nucleon scattering data at the physical light-quark masses. We find weak evidence that both the deuteron and the di-neutron are bound at this pion mass, with binding energies of B{sub d} = 11(05)(12) MeV and B{sub nn} = 7.1(5.2)(7.3) MeV, respectively. With an increased number of measurements and a refined analysis, the binding energy of the H-dibaryon is B{sub H} = 13.2(1.8)(4.0) MeV at this pion mass, updating our previous result.

Light Nuclei and Hypernuclei from Quantum Chromodynamics in the Limit of SU(3) Flavor Symmetry

The binding energies of a range of nuclei and hypernuclei with atomic number A 4 and strangeness jsj 2, including the deuteron, di-neutron, H-dibaryon, 3 He, 3 He, 4 He, 4 He, and 4 He, are calculated in the limit of avor-SU(3) symmetry at the physical strange-quark mass with quantum chromodynamics (without electromagnetic interactions). The nuclear states are extracted from Lattice QCD calculations performed with nf = 3 dynamical light quarks using an isotropic clover discretization of the quark action in three lattice volumes of spatial extent L 3:4 fm; 4:5 fm and 6:7 fm, and with a single lattice spacing b 0:145 fm.

Precise determination of the I=2 pi pi scattering length from mixed-action lattice QCD

The

Exploring hyperons and hypernuclei with lattice QCD

I=2

Multipion states in lattice QCD and the charged-pion condensate

\ensuremath{\pi}\ensuremath{\pi}

The I=2 pi-pi S-wave Scattering Phase Shift from Lattice QCD

scattering length is calculated in fully dynamical lattice QCD with domain-wall valence quarks on the asqtad-improved coarse MILC configurations (with fourth-rooted staggered sea quarks) at four light-quark masses. Two- and three-flavor mixed-action chiral perturbation theory at next-to-leading order is used to perform the chiral and continuum extrapolations. At the physical charged pion mass, we find

Present constraints on the H-dibaryon at the physical point from Lattice QCD

{m}_{\ensuremath{\pi}}{a}_{\ensuremath{\pi}\ensuremath{\pi}}^{I=2}=\ensuremath{-}0.043\text{ }30\ifmmode\pm\else\textpm\fi{}0.000\text{ }42