The possible Σ0\Sigma^0-Λ\Lambda mixing in QCD sum rules

We calculate the on-shell $\Sigma^0$-$\Lambda$ mixing parameter $\theta$ with the method of QCD sum rule. Our result is $\theta (m^2_{\Sigma^0}) =(-)(0.5\pm 0.1)$MeV. The electromagnetic interaction is not included

The exclusive \bar{B} --> \pi e^+ e^- and \bar{B} --> \rho e^+ e^- decays in the two Higgs doublet model with flavor changing neutral currents

We calculate the leading logarithmic QCD corrections to the matrix element of the decay b --> d e^+ e^- in the two Higgs doublet model with tree level flavor changing currents (model III). We continue studying the differential branching ratio and the CP violating asymmetry for the exclusive decays B --> \pi e^+ e^- and B --> \rho e^+ e^- and analysing the dependencies of these quantities on the selected model III parameters, \xi^{U,D}, including the leading logarithmic QCD corrections. Further, we present the forward-backward asymmetry of dileptons for the decay B --> \rho e^+ e^- and discuss the dependencies to the model III parameters. We observe that there is a possibility to enhance the branching ratios and suppress the CP violating effects for both decays in the framework of the model III. Therefore, the measurements of these quantities will be an efficient tool to search the new physics beyond the SM.Comment: 27 pages, 14 Figure

Multiparton interactions and production of minijets in high energy hadronic collisions

We discuss the inclusive cross section to produce two minijets with a large separation in rapidity in high energy hadronic collisions. The contribution to the inclusive cross section from the exchange of a BFKL Pomeron is compared with the contribution from the exchange of two BFKL Pomerons, which is induced by the unitarization of the semi-hard interaction. The effect of the multiple exchange is studied both as a function of the azimuthal correlation and as a function of the transverse momentum of the observed minijets.Comment: TeX file, 20 pages, 4 figures available on reques

Growing Environmental Activists: Developing Environmental Agency and Engagement Through Children’s Fiction.

We explore how story has the potential to encourage environmental engagement and a sense of agency provided that critical discussion takes place. We illuminate this with reference to the philosophies of John Macmurray on personal agency and social relations; of John Dewey on the primacy of experience for philosophy; and of Paul Ricoeur on hermeneutics, dialogue, dialectics and narrative. We view the use of fiction for environmental understanding as hermeneutic, a form of conceptualising place which interprets experience and perception. The four writers for young people discussed are Ernest Thompson Seton, Kenneth Grahame, Michelle Paver and Philip Pullman. We develop the concept of critical dialogue, and link this to Crick's demand for active democratic citizenship. We illustrate the educational potential for environmental discussions based on literature leading to deeper understanding of place and environment, encouraging the belief in young people that they can be and become agents for change. We develop from Zimbardo the key concept of heroic resister to encourage young people to overcome peer pressure. We conclude with a call to develop a greater awareness of the potential of fiction for learning, and for writers to produce more focused stories engaging with environmental responsibility and activism

Isospin Breaking in the Pion-Nucleon Coupling from QCD Sum Rules

We use QCD sum rules for the three point function of a pseudoscalar and two nucleonic currents in order to estimate the charge dependence of the pion nucleon coupling constant $g_{NN\pi}$ coming from isospin violation in the strong interaction. The effect can be attributed primarily to the difference of the quark condensates $$and$$. For the splitting $(g_{pp\pi_0} - g_{nn\pi_0}) / g_{NN\pi}$ we obtain an interval of $1.2 * 10^{-2}$ to $3.7 * 10^{-2}$, the uncertainties coming mainly from the input parameters. The charged pion nucleon coupling is found to be the average of $g_{pp\pi_0}$ and $g_{nn\pi_0}$. Electromagnetic effects are not included.Comment: 18 pages (REVTeX) + 2 figures (as PostScript), to be published in PRC, replaced with final version: inclusion of pi-eta mixing and N -> N* transition

Signals for Double Parton Scattering at the Fermilab Tevatron

Four double-parton scattering processes are examined at the Fermilab Tevatron energy. With optimized kinematical cuts and realistic parton level simulation for both signals and backgrounds, we find large samples of four-jet and three-jet+one-photon events with signal to background ratio being 20\%-30\%, and much cleaner signals from two-jet+two-photon and two-jet+$e^+e^-$ final states. The last channel may provide the first unambiguous observation of multiple parton interactions, even with the existing data sample accumulated by the Tevatron collider experiments.Comment: 7 pages, plain LaTeX, 2 tables, no figures. A compressed PS file is available by anonymous ftp at ftp://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-945.ps.

The CP asymmetry for B--> K^* l^+ l^- decay in the general two Higgs doublet model

We study CP asymmetry for the exclusive decay B --> K^* l^+ l^- in the two Higgs doublet model with three level flavor changing neutral currents (model III). We analyse the dependency of this quantity to the new phase coming from the complex Yukawa couplings in the theory and we find that there exist a considerable CP violation for the relevant process. Further, we see that the sign of the Wilson coefficient C_7^{eff} can be determined by fixing dilepton mass. Therefore, the future measurements of CP asymmetry for B --> K^* l^+ l^- decay will give a powerful information about the sign of Wilson coefficient C_{7}^{eff} and the new physics beyond the SM.Comment: 22 pages, 8 figure

Discriminating graviton exchange effects from other new physics scenarios in e^+e^- collisions

We study the possibility of uniquely identifying the effects of graviton exchange from other new physics in high energy e^+e^- annihilation into fermion-pairs. For this purpose, we use as basic observable a specific asymmetry among integrated differential distributions, that seems particularly suitable to directly test for such gravitational effects in the data analysis.Comment: 18 pages, including figures; v2: additional references and acknowledgements. To appear in PR

Exclusive B -> pi e^+ e^- and B -> rho e^+ e^-

We investigate the exclusive B -> pi e^+ e^- and B -> rho e^+ e^- decays in framework of the general two Higgs doublet model (model III), in which an extra phase angle in the charged--Higgs fermion coupling, i.e., a new source for CP violation exists. The CP violation for both decays are calculated and it is observed that the CP violating asymmetry in model III differs significantly than the one predicted by the standard model and model II which is a special case of model III. Furthermore, it is shown that the zero value of forward backward asymmetry A_{FB} is shifted when compared with the SM value, which can also serve as the efficiency tool for establishing new physics.Comment: 21 pages, 8 figures, 4 Tables LaTeX formatte

Exclusive B --> K^* l^+ l^-$ decay in the three Higgs doublet model

We study the differential Branching ratio and CP asymmetry for the exclusive decay B --> K^* l^+ l^- in the three Higgs doublet model with additional global O(2) symmetry in the Higgs sector. We analyse dilepton mass square q^2 dependency of the these quantities. Further, we study the effect of new parameter of the global symmetry in the Higgs sector on the differential branching ratio and CP asymmetry. We see that there exist an enhancement in the branching ratio and a considerable CP violation for the relevant process. In addition to this, we realize that fixing dilepton mass gives information about the sign of the Wilson coefficient C_7^{eff}.Therefore, the future measurements of the CP asymmetry for B\to K^* l^+ l^- decay will give a powerful information about the sign of Wilson coefficient C_{7}^{eff} and new physics beyond the SM.Comment: 19 pages, 6 figure