Results 1 - 10 of 991
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[en] Predictions are made in the framework of the effective color field (ECF) model for polarization observables in , A + A → ΛX and p + Pb → pX reactions. The predictions can be checked in the polarization experiments at IHEP (SPASCHARM), JINR (NICA) and BNL (RHIC). Estimates of quark masses and anamolous chromomagnetic quark moments are given.
[en] Preliminary results on the spin transfer to the Λ and hyperons measured by the HERMES Collaboration are presented. Longitudinal spin transfer directed along the virtual-photon momentum in the Λ rest frame is found to be DΛ LL = 0.19 ± 0.04stat ± 0.02syst, the transverse component being compatible with zero. For both longitudinal and transverse components are compatible with zero within statistical errors of ±0.1.
[en] Full text: We present a study of the measurement of the Lambda and anti-Lambda production within LHCb, a dedicated b-physics experiment at LHC. This is expected to be one of the first measurements achievable with approximately 100 million minimum bias events collected in the early phase of the experiment. The hadronization process responsible for strange baryon production is not yet fully understood. Current phenomenological models tuned on Tevatron data show divergences when extrapolated to LHC energies. Since LHCb is covering an angular region complementary to the other LHC detectors, such measurements will provide valuable input for understanding the hadronization and fragmentation models, and tuning the MC generators used by all LHC experiments. This work will also provide a starting point for the study of multistrange baryon production, as well as measurements in the heavy-flavour baryon sector. (author)
[en] In this talk I discuss the possibility of producing new types of nuclear systems by implanting an antibaryon into ordinary nuclei. The structure of nuclei containing one antiproton or antilambda is investigated within the framework of a relativistic mean-field model. Self-consistent calculations predict an enhanced binding and considerable compression in such systems as compared with normal nuclei. I present arguments that the life time of such nuclei with respect to the antibaryon annihilation might be long enough for their observation
[en] A schematic Monte Carlo simulation is used to examine the potential of exclusive hyperon-antihyperon pair production close to threshold in antiproton nucleus interactions to extract information on the interaction of antihyperons in nuclei. It is demonstrated that for ΛΛ¯ pairs produced at antiproton momenta of 1.66 GeV/c the asymmetry is sufficiently sensitive even if the density as well as the momentum dependencies of the potentials are considered. Data taken earlier by the PS185 Collaboration prove that these measurements are feasible. (author)
[en] The possibility of observing ΛantiΛ heavy states using the Isabelle storage rings is discussed. Not many particles are known to date to decay into ΛantiΛ. The J/psi is a notable exception, with a branching ratio of about 0.2% (vs. 7% into e+e- and μ+μ-). However, it is not inconceivable that higher mass states, produced at Isabelle energies, will have substantial branching fractions into ΛantiΛ. If this will indeed be the case, then one may think of getting additional information on the properties of the new states by taking advantage of the parity-violating Λ and antiΛ decays. Detectors, rate and background considerations, and methods of particle detection are discussed
[en] Let be a locally compact separable ultrametric space. Given a measure on and a function defined on the set of all balls of positive measure of , we consider the hierarchical Laplacian . The operator acts on . It is essentially self-adjoint and has a pure point spectrum. By choosing a family of independent identically distributed random variables, we define the perturbed function and the perturbed hierarchical Laplacian . We study the arithmetic means of the eigenvalues of . Under some mild assumptions the normalized arithmetic means converge to in distribution. We also give examples when the normal convergence fails. We prove the existence of an integrated density of states. Introducing an empirical point process for the eigenvalues of and assuming that the density of states exists and is continuous, we prove that the finite-dimensional distributions of converge to those of the Poisson point process. As an example we consider random perturbations of the Vladimirov operator acting on , where is the ring of -adic numbers and is the Haar measure.
[en] Samples of Λ and hyperons produced in deep-inelastic muon scattering off 6LiD target were collected with the COMPASS experimental setup at CERN. The relative yields of Σ-(1385), , , Ξ−(1321), and hyperons decaying into the were measured. The yield ratios of heavy hyperons to Λ were found to be in the range 3.8%–5.6% with a precision of about 10%. The experimental values are used to tune the parameters of the LEPTO Monte-Carlo generator relevant for strange particle production.