The polarized targets

Yokosawa, A.

doi:10.1063/1.32207

Cited by 13 publications

(19 citation statements)

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“…(2,2) are unbound because they present quark Pauli blocking that, as in the case of the ∆∆ system, will play an important role in the three-body spectrum. The state (j, i) = (2, 1) can also exist in the NN system and there it corresponds to the 1 D 2 partial wave which has a resonance at an invariant mass of 2.17 GeV [235][236][237]. This means that the N∆ bound state may decay into two nucleons and appear in the NN system as a resonance.…”

Section: Resultsmentioning

confidence: 99%

Quark-model study of few-baryon systems

et al. 2005

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Abstract. We review the application of non-relativistic constituent quark models to study one, two and three non-strange baryon systems. We present results for the baryon spectra, potentials and observables of the NN, N∆, ∆∆ and NN * (1440) systems, and also for the binding energies of three non-strange baryon systems. We make emphasis on observable effects related to quark antisymmetry and its interplay with quark dynamics.

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Section: Resultsmentioning

confidence: 99%

Quark-model study of few-baryon systems

et al. 2005

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“…The code developed by Hawley et al (1984a,b) was capable of keeping stable discs in equilibrium as well as of following the fate of initially unstable models. Yokosawa (1995) studied the structure and dynamics of relativistic accretion discs and the transport of energy and angular momentum in magnetohydrodynamical accretion on to a rotating black hole. More recently, Igumenshchev & Beloborodov (1997) performed a similar study as Hawley et al (1984a,b), including the rotating black hole case and using improved numerical methods based on Riemann solvers.…”

Section: Introductionmentioning

confidence: 99%

The runaway instability of thick discs around black holes - I. The constant angular momentum case

Font

Daigne

2002

Monthly Notices of the Royal Astronomical Society

136

199

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We present results from a numerical study of the runaway instability of thick discs around black holes. This instability is an important issue for most models of cosmic gamma‐ray bursts, where the central engine responsible for the initial energy release is such a system consisting of a thick disc surrounding a black hole. We have carried out a comprehensive number of time‐dependent simulations aimed at exploring the appearance of the instability. Our study has been performed using a fully relativistic hydrodynamics code. The general relativistic hydrodynamic equations are formulated as a hyperbolic flux‐conservative system and solved using a suitable Godunov‐type scheme. We build a series of constant angular momentum discs around a Schwarzschild black hole. Furthermore, the self‐gravity of the disc is neglected and the evolution of the central black hole is assumed to be that of a sequence of exact Schwarzschild black holes of varying mass. The black hole mass increase is thus determined by the mass accretion rate across the event horizon. In agreement with previous studies based on stationary models, we find that by allowing the mass of the black hole to grow the disc becomes unstable. Our hydrodynamical simulations show that for all disc‐to‐hole mass ratios considered (between 1 and 0.05), the runaway instability appears very fast on a dynamical time‐scale of a few orbital periods, typically a few 10 ms and never exceeding 1 s for our particular choice of the mass of the black hole (2.5 M⊙) and a large range of mass fluxes (m˙≳10‐3 M⊙ s‐1). The implications of our results in the context of gamma‐ray bursts are briefly discussed.

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“…4(b)]. The no-net helicity fiip amplitude y2 (we use Yokosawa's notation [18]) is largest at 8=0 and falls exponentially between 0 and 60, while the double-Qip helicity amplitude y4 rises from zero at 0=0 to a maximum around 0=40' and decreases again. The other helicity amplitudes y& 3 5 are less important in forward direction.…”

Section: Resultsmentioning

confidence: 99%

Bonn nucleon-nucleon meson exchange model with a relativistic quark-gluon annihilation potential

1991

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The full Bonn potential, combined with a relativistic quark-gluon annihilation potential, is compared with recent NN polarization data from LEAR and with measured differential cross sections (elastic and charge exchange) below p&, b=800 MeV/c. It is demonstrated within this approach that a careful analysis of pp~pp(EL) and pp -+nn(CEX), at the same energy, in terms of the five independent helicity amplitudes can be used to selectively test specific boson exchange contributions to NN scattering. The charge-exchange differential cross section in forward direction is particularly sensitive to the one-pionexchange potential in this model. This feature could be used to see if recent attempts to fit NN data with a much softer mNN form factor can be made compatible with NN data.

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The polarized targets

Cited by 13 publications

References 0 publications

Quark-model study of few-baryon systems

Quark-model study of few-baryon systems

The runaway instability of thick discs around black holes - I. The constant angular momentum case

Bonn nucleon-nucleon meson exchange model with a relativistic quark-gluon annihilation potential

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