117796835
Static three-body potential in baryons
The first principle of quantum chromodynamics is used to calculate the static perturbative three-body potential between three valence quarks in baryons, which is gauge invariant and flavor-dependent, and of magnitude of the same order as the next non-leading static q-q potential. Its effect on an S-state baryon composed of three valence quarks of equal mass may be viewed as a slight increase of the constituent quark masses with respect to those in mesons.
121124456
An Extended Chiral SU(3) Quark Model
The chiral SU(3) quark model is extended by including the vector meson exchanges to describe the short range interactions. The phase shifts of NN scattering are studied in this model. Compared with the results of the chiral SU(3) quark model in which only the pseudo-scalar and scalar chiral fields are considered, the phase shifts of 1S0 wave are obviously improved.
121034531
Strange hadronic matter in a chiral model
The strange hadronic matter with nucleon, Λ-hyperon and Ξ-hyperon is studied by using a chiral symmetry model in a mean-field approximation. The saturation properties and stabilities of the strange hadronic matter are discussed. The result indicates a quite large strangeness fraction (fS) region where the strange hadronic matter is stable against particle emission. In the large fS region, the Ξ component dominates, resulting in a deep minimum in the curve of the binding energy per baryon EB versus the strangeness fraction fS with (EB, fS) (-26.0 MeV, 1.23).
53311398
Chiral extrapolation of nucleon magnetic form factors
The extrapolation of nucleon magnetic form factors calculated within lattice QCD is investigated within a framework based upon heavy baryon chiral effective-field theory. All one-loop graphs are considered at arbitrary momentum transfer and all octet and decuplet baryons are included in the intermediate states. Finite range regularization is applied to improve the convergence in the quark-mass expansion. At each value of the momentum transfer (${Q}^{2}$), a separate extrapolation to the physical pion mass is carried out as a function of ${m}_{\ensuremath{\pi}}$ alone. Because of the large values of ${Q}^{2}$ involved, the role of the pion form factor in the standard pion-loop integrals is also investigated. The resulting values of the form factors at the physical pion mass are compared with experimental data as a function of ${Q}^{2}$ and demonstrate the utility and accuracy of the chiral extrapolation methods presented herein.
118632293
Nucleon magnetic form factors with non-local chiral effective Lagrangian
Chiral perturbation theory is a useful method to investigate the hadron properties. We apply the non-local chiral effective Lagrangian to study the nucleon magnetic form factors. The octet and decuplet intermediate states are included in the one-loop calculation. With the modified propagators and non-local interaction, the loop integral is convergent. The obtained proton and neutron magnetic form factors are both reasonable up to relatively large Q2.
208023776
Strange magnetic form factor of nucleon in heavy baryon chiral effective approach at next to leading order
d ARC Centre of Excellence in Particle Physics at the Terascale, School of Chemistry & Physics, University of Adelaide, SA 5005, Australia Abstract The strange magnetic form factor of the nucleon is studied in the heavy baryon chiral effective approach at next to leading order. The one loop contributions from kaon and intermediate octet and decuplet hyperons are included, using finite-range-regularization to deal with the ultra-violet divergences. Drawing on an established connection between quenched and full QCD, this model makes it possible to predict the strange magnetic form factor under the hypothesis that for a dipole regulator mass Λ around 0.8 GeV, strangeness in the core is negligible. The strange magnetic form factor is found to be small and negative over a range of momentum transfer, while the strange magnetic moment is consistent with the best lattice QCD determinations.
126292990
Search for new charmonium states in the processes e+ e- ---> J/psi D(*) anti-D(*) at s**(1/2) ~ 10.6-GeV
14125535
Dynamical Treatment of Virialization Heating in Galaxy Formation
In a hierarchical picture of galaxy formation virialization continually transforms gravitational potential energy into kinetic energies of the baryonic and dark matter. For the gaseous component the kinetic, turbulent energy is transformed eventually into internal thermal energy through shocks and viscous dissipation. Traditionally this virialization and shock heating has been assumed to occur instantaneously, allowing an estimate of the gas temperature to be derived from the virial temperature defined from the embedding dark matter halo velocity dispersion. As the mass grows the virial temperature of a halo grows. Mass accretion hence can be translated into a heating term. We derive this heating rate from the extended Press Schechter formalism and demonstrate its usefulness in semianalytical models of galaxy formation. Our method explicitly conserves energy, unlike the previous impulsive heating assumptions. Our formalism can trivially be applied in all current semianalytical models as the heating term can be computed directly from the underlying merger trees. Our analytic results for the first cooling halos and the transition from cold to hot accretion are in agreement with numerical simulations.
118225508
Study of \Omega_c^0 and \Omega_c^{*0} Baryons at Belle
We report results from a study of the charmed double strange baryons \Omega_c^0 and \Omega_c^{*0} at Belle. The \Omega_c^0 is reconstructed using the \Omega_c^0 --> \Omega^- \pi^+ decay mode, and its mass is measured to be (2693.6 \pm 0.3 {+1.8 \atop -1.5}) MeV/c^2. The \Omega_c^{*0} baryon is reconstructed in the \Omega_c^0 \gamma mode. The mass difference M_{\Omega_c^{*0}} - M_{\Omega_c^0} is measured to be (70.7 \pm 0.9 {+0.1 \atop -0.9}) MeV/c^2. The analysis is performed using 673 fb^{-1} of data on and near the \Upsilon(4S) collected with the Belle detector at the KEKB asymmetric-energy e^+e^- collider.
119283952
Measurements of the masses and widths of the $\Sigma_{c}(2455)^{0/++}$ and $\Sigma_{c}(2520)^{0/++}$ baryons
We present measurements of the masses and decay widths of the baryonic states (2455) and (2520) using a data sample corresponding to an integrated luminosity of 711 fb- 1 collected with the detector at the KEKB e e- asymmetric- energy collider operating at the.(4S) resonance. We report the mass differences with respect to the A(c) baryon.
119221523
Search for Dark Matter Satellites Using FERMI -LAT
Numerical simulations based on the Lambda-CDM model of cosmology predict a large number of as yet unobserved Galactic dark matter satellites. We report the results of a Large Area Telescope (LAT) search for these satellites via the gamma-ray emission expected from the annihilation of weakly interacting massive particle (WIMP) dark matter. Some dark matter satellites are expected to have hard gamma-ray spectra, finite angular extents, and a lack of counterparts at other wavelengths. We sought to identify LAT sources with these characteristics, focusing on gamma-ray spectra consistent with WIMP annihilation through the $b \bar b$ channel. We found no viable dark matter satellite candidates using one year of data, and we present a framework for interpreting this result in the context of numerical simulations to constrain the velocity-averaged annihilation cross section for a conventional 100 GeV WIMP annihilating through the $b \bar b$ channel.