119675401
Gluonic two-particle potential
A method developed recently by us for the derivation of the electromagnetic and gravitational two-particle potentials is applied to a model of scalars and gluons based on the gauge group $\mathrm{SU}(N)$, and thus the fourth-order gluonic two-particle potential is derived to order ${c}^{\ensuremath{-}2}$. Besides the leading term in our gluonic potential, which is in agreement with the results of earlier authors, we obtain the next-to-leading terms representing a shorter-range massdependent interaction.
120383870
Higgs model with ghost-field formalism
The Higgs model for the interaction of vector and scalar fields is treated by means of the ghost-field formalism, which preserves the unitarity of the scattering operator as well as simplifies the renormalization procedure. Our ghost-field formalism has some similarity to the ${R}_{\ensuremath{\xi}}$ formalism with $\ensuremath{\xi}=1$, but it does not require the introduction of the so-called gauge-compensating terms. Applications to the second-order self-energy of a scalar particle and to the fourth-order scattering of vector particles are discussed.
121663425
Quantum-chromodynamic potential model for light and heavy quarkonia
Our earlier treatment for the investigation of the cc-bar, bb-bar, and tt-bar spectra is extended to other p quarkonia with u, d, s, c, and b quarks. We find that it is possible to account fully for the observed ground-state hyperfine splittings of light as well as heavy quarkonia provided that the perturbative quantum-chromodynamic potential is supplemented not only by the nonperturbative confining potential but also by a nonperturbative annihilation potential which rapidly decreases with increase in the quark mass. We also give our predictions for the experimentally interesting bu-bar, bs-bar, and bc-bar systems with unknown mass splittings.
6552264
Nonsingular potential model for heavy quarkonia.
A nonsingular potential model for heavy quarkonia is described which does not require recourse to an illegitimate perturbative treatment for the investigation of quarkonium spectra. Our overall results for the energy levels, the leptonic widths, and the E1 transition widths are in very good agreement with the experimental data for bb-bar and they are reasonably good for cc-bar. We also find that the confining part of the quarkonium potential is scalar-vector exchange rather than the currently favored scalar exchange.
122167852
MULTIPLE PHOTON PRODUCTION IN QUANTUM ELECTRODYNAMICS
Multiple production of photons in high-energy processes in quantum electrodynamics is investigated, and the electron-positron annihilation is specially discussed in detail. It is found that at very high energies in cosmic rays, multiple production of up to four or five observable photons can easily take place. But, the probability, according to quantum electrodynamics, for the multiple production of a larger number of observable photons is quite small.
122156675
Relativistic Hadron Model with Intrinsic Mass Splittings
A simple mechanism for the $\mathrm{SU}(3)$-symmetry breaking in strong interactions is introduced by using the formalism of the multispinor field equations, which avoids the use of physical quarks but has resemblance to the quark model. The resulting treatment leads to the Gell-Mann-Okubo mass formula for baryons, but not for mesons. It yields approximate values of -19.5\ifmmode^\circ\else\textdegree\fi{} and 33\ifmmode^\circ\else\textdegree\fi{} for the $\ensuremath{\eta}\ensuremath{-}{\ensuremath{\eta}}^{\ensuremath{'}}$ and $\ensuremath{\varphi}\ensuremath{-}\ensuremath{\omega}$ mixing angles, respectively, and also provides a reasonable explanation for the intermultiplet meson mass formula $m_{K}^{}{}_{}{}^{2}\ensuremath{-}m_{\ensuremath{\pi}}^{}{}_{}{}^{2}=m_{{K}^{*}}^{}{}_{}{}^{2}\ensuremath{-}m_{\ensuremath{\rho}}^{}{}_{}{}^{2}$.
123477095
High-energy pulsed gamma rays from pulsars
Ten pulsars were observed for pulsed emission of gamma rays at energies greater than 500 GeV, using an atmospheric Cerenkov emission technique. Signals at the levels of 3.85 and 3.56 sigmas were detected from PSR 0950+08 and PSR 0531+21 (Crab pulsar), respectively. If the signal from the Crab pulsar is attributed to the main pulse, a further 2.2-sigma signal is found in the same data, precisely at the place predicted for interpulse by the observations on low-energy gamma rays from COS-B satellite. The statistical significance of the results is discussed.
118984972
Calculations for populations of selected isotopes in intermediate-energy heavy ion collisions
We compute the populations of isotopes of Boron, Carbon and Nitrogen measured experimentally in intermediate energy heavy ion collisions. A two component soluble statistical model is used to find the initial populations of different nuclei at a finite temperature. These initial populations are both in particle stable and particle unstable states. The particle unstable states then decay. The final populations after these decays are computed and compared with experimental data.
120975097
Magnetic moments of light baryons in harmonic model
Abstract Anomalous magnetic moments of light baryons are calculated in a relativistic harmonic oscillator model to obtain good agreement with experiment.
119263848
Finite size scaling on the phase diagram of QCD
In the last few years there has been remarkable progress in the comparison of experimental data on the shape of event-by-event distributions of conserved quantities and lattice thermodynamic predictions based on the grand canonical ensemble. In this talk we discuss how the QCD crossover temperature and the freezeout curve are extracted from the analysis of fluctuations. We report that one can also go further and locate the QCD critical point at µ }~ 2Tc. We also list the systematics which must be brought under control in future.
14798493
Effects of momentum-dependent symmetry potential on heavy-ion collisions induced by neutron-rich nuclei
Abstract Using an isospin- and momentum-dependent transport model we study effects of the momentum-dependent symmetry potential on heavy-ion collisions induced by neutron-rich nuclei. It is found that symmetry potentials with and without the momentum-dependence but corresponding to the same density-dependent symmetry energy E sym ( ρ ) lead to significantly different predictions on several E sym ( ρ )-sensitive experimental observables especially for energetic nucleons. The momentum- and density-dependence of the symmetry potential have to be determined simultaneously in order to extract the E sym ( ρ ) accurately. The isospin asymmetry of midrapidity nucleons at high transverse momenta is particularly sensitive to the momentum-dependence of the symmetry potential. It is thus very useful for investigating accurately the equation of state of dense neutron-rich matter.