Possible dynamical mechanism generatingSU 3 andSU 2 symmetry breaking

We discuss a dynamical mechanism forSU3 andSU2 symmetry breaking, based on scalar-meson-dominated tadpoles with σ-model-inspired meson and quark couplings. Meson and baryon mass differences are consistently described in terms of the two strange and nonstrange scalar-meson couplings to currents, and octet enhancement is obtained in a natural way

Measuring Double Parton Distributions in Nucleons at Proton-Nucleus Colliders

We predict a strong enhancement of multijet production in proton-nucleus collisions at collider energies, as compared to a naive expectation of a cross section $\propto A$. The study of the process would allow to measure, for the first time, the double parton distribution functions in a nucleon in a model independent way and hence to study both the longitudinal and the transverse correlations of partons.Comment: 12 pages, 2 figure

High-pTp_T ψψ\psi\psi production as signals for Double Parton scattering at hadron colliders

We present an analysis of the \psi\psi production from double parton (DP) sacttering and single parton (SP) scattering in the large p_T region via color-octet gluon fragmentation. We find that at the Tevatron the DP \psi\psi production is at the edge of the detectability at present, and at the LHC the DP cross section will dominate over the SP cross section in the lower p_T(min) region (i.e., p_T(min)<7GeV). We also conclude that the color-octet mechanism is of crucial importance to the double j/psi production at high energy hadron colliders.Comment: Revtex, 12 pages, 3 Postscript figure

b \bar b b\bar b production in proton-nucleus collisions at the LHC

A sizable rate of events, with several pairs of $b$-quarks produced contemporarily by multiple parton interactions, may be expected at very high energies as a consequence of the large parton luminosities. The production rates are further enhanced in hadron-nucleus reactions, which may represent a convenient tool to study the phenomenon. We compare the different contributions to $b{\bar b}b{\bar b}$ production, due to single and double parton scatterings, in collisions of protons with nuclei at the CERN-LHC.Comment: 13 pages, 4 figure

``Non-factorizable'' terms in hadronic B-meson weak decays

The branching ratios for the hadronic B-meson weak decays B -> J/psi K and B -> D pi are used to extract the size of the ``non-factorizable'' terms in the decay amplitudes. It is pointed out that the solutions are not uniquely determined. In the B -> J/psi K case, a 2-fold ambiguity can be removed by analyzing the contribution of this decay to B -> K l+ l-. In the B -> D pi case, a 4-fold ambiguity can only be removed if the ``non-factorizable'' terms are assumed to be a small correction to the vacuum insertion result.Comment: 15 pages (and 1 figure, available upon request), TRIUMF report no. TRI-PP-94-7

Dynamical SU(3) linear sigma model and the mixing of eta'-eta and sigma-f_0 mesons

The SU(3) linear sigma model is dynamically generated in loop-order using the nonstrange-strange basis. Only self-consistent logarithmic divergent graphs are needed, with quadratic divergent graphs replaced by SU(3) mass-shell equal splitting laws. The latter lead to an eta'-eta mixing angle of 41.84 deg which is consistent with phenomenology. Finally this above SU(3) linear sigma model in turn predicts strong decay rates which are all compatible with data.Comment: 14 pages, 1 figure, elsart; version to appear in J. Phys. G, appendix added, some typos correcte

Exclusive B -> K^* l^+ l^- decay with polarized K^* and new physics effects

Using the most general, model independent effective Hamiltonian, the branching ratio of the (B -> K^* l^+ l^-) decay, when K^* meson is longitudinally or transversally polarized, is presented. The dependence of the branching ratio on the new Wilson coefficients, when K^* meson is polarized, is studied. It is observed that the branching ratio is very sensitive to the vector and tensor type interactions, which will be useful in search of new physics beyond the Standard Model.Comment: 13 pp, 6 figures (postscript formatted), LaTex formatte

A double parton scattering background to Higgs boson production at the LHC

The experimental capability of recognizing the presence of b quarks in complex hadronic final states has addressed the attention towards final states with b\bar{b} pairs for observing the production of the Higgs boson at the LHC, in the intermediate Higgs mass range.We point out that double parton scattering processes are going to represent a sizeable background to the process.Comment: 9 pages, 2 figure

Scale Factor in Double Parton Collisions and Parton Densities in Transverse Space

The scale factor $\sigma_{eff}$, which characterizes double parton collisions in high energy hadron interactions, is a direct manifestation of the distribution of the interacting partons in transverse space, in such a way that different distributions give rise to different values of $\sigma_{eff}$ in different double parton collision processes. We work out the value of the scale factor in a few reactions of interest, in a correlated model of the multi-parton density of the proton recently proposed.Comment: 10 pages, 2 figure