Production rates for hadrons, pentaquarks Θ+\Theta ^+ and Θ∗++\Theta ^{*++}, and di-baryon (ΩΩ)0+(\Omega\Omega)_{0^{+}} in relativistic heavy ion collisions by a quark combination model

The hadron production in relativistic heavy ion collisions is well described by the quark combination model. The mixed ratios for various hadrons and the transverse momentum spectra for long-life hadrons are predicted and agree with recent RHIC data. The production rates for the pentaquarks $\Theta ^+$, $\Theta ^{*++}$ and the di-baryon $(\Omega\Omega)_{0^{+}}$ are estimated, neglecting the effect from the transition amplitude for constituent quarks to form an exotic state.Comment: The difference between our model and other combination models is clarified. The scaled transverse momentum spectra for pions, kaons and protoms at both 130 AGeV and 200 AGeV are given, replacing the previous results in transverse momentum spectr

Probability of Color Rearrangement at Partonic Level in Hadronic W^+W^- Decays

A strict method to calculate the color rearrangement probability at partonic level in hadronic $W^+W^-$ decays is proposed. The color effective Hamiltonian $H_c$ is constructed from invariant amplitude for the process $e^+e^- \to W^+W^- \to q_1\bar{q}_2 q_3\bar{q}_4+ng$ (n=0, 1, 2, ...) and is used to calculate the cross sections of various color singlets and the color rearrangement probability. The true meaning of the color rearrangement is clarified and its difference from color interference is discussed.Comment: 16 pages, Late

Properties of color singlet chain states in e+e−e^+e^- annihilation

We use the method of the color effective Hamiltonian to study the structure of color singlet chain states in $N_c=3$ and in the large $N_c$ limit. In order to obtain their total fraction when $N_c$ is finite, we illustrate how to orthogonalize these non-orthogonal states. We give numerical results for the fraction of orthogonalized states in $e^+e^-\to q\bar{q}gg$. With the help of a diagram technique, we derive their fraction up to $O(1/N_c^2)$ for the general multigluon process. For large $N_c$ the singlet chain states correspond to well-defined color topologies. Therefore we may expect that the fraction of non-color-singlet-chain states is an estimate of the fraction of events where color reconnection is possible. In the case of soft gluon bremsstrahlung, we give an explicit form for the color effective Hamiltonian which leads to the dipole cascade formulation for parton showering in leading order in $N_c$. The next-to-leading order corrections are also given for $e^+e^-\to q\bar{q}g_1g_2$ and $e^+e^-\to q\bar{q}g_1g_2g_3$.Comment: RevTex, 23 pages, 5 figures; Phys. Rev. D accepted versio