130 research outputs found
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
The Radiative Decay of Vector Mesons
In this paper, radiative decays , are studied
systematically in the U(3)_L\timesU(3)_R chiral theory of mesons. The
theoretical differential spectrum with respect to photon energy and branch
ratio for agree well with the experimental data.
Differential spectrums and branch ratios for are predicted. The process is relevant to precision measurment of CP-violation
parameters in the kaon systerm at a -factory. We give a complete estimate
of the branch ratio for this decay process by including scalar resonance poles, nonresonant smooth amplitude and an abnormal parity process with
pole which hasn't been considered before. We conclude that processes with
intermediate do not pose a potential background problem for CP violation experiments.Comment: Revtex file, 12 pages, 9 eps figure
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
Multiple Parton Interactions in Z+jets production at the LHC. A comparison of factorized and non--factorized double parton distribution functions
We examine the contribution of Multiple Parton Interactions to Z+n-jets
production at the LHC, n=2,3,4, where the Z boson is assumed to decay
leptonically. We compare the results obtained with the correlated GS09 double
parton distribution function with those obtained with two instances of fully
factorized single parton distribution functions: MSTW2008LO and CTEQ6LO. It
appears quite feasible to measure the MPI contribution to Z+2/3/4 jets already
in the first phase of the LHC with a total luminosity of one inverse femtobarn
at 7 TeV. If as expected the trigger threshold for single photons is around 80
GeV, Z+2-jets production may well turn out to be more easily observable than
the gamma+3-jets channel. The MPI cross section is dominated by relatively soft
events with two jets balancing in transverse momentum.Comment: 15 pages, 3 plot
Kaon decay interferometry as meson dynamics probes
We discuss the time dependent interferences between and in the
decays in and , to be studied at interferometry machines
such as the -factory and LEAR. We emphasize the possibilities and the
advantages of using interferences, in comparison with width measurements, to
obtain information both on conserving and violating amplitudes.
Comparison with present data and suggestions for future experiments are made.Comment: 15 pages, in RevTex, Report INFNNA-IV-93-31, UTS-DFT-93-2
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
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
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 coming from isospin violation in the
strong interaction. The effect can be attributed primarily to the difference of
the quark condensates . For the splitting
we obtain an interval of to , the uncertainties coming mainly from the input
parameters. The charged pion nucleon coupling is found to be the average of
and . 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
CP Asymmetry of in Low Invariant Mass Region
I analyzed the CP asymmetry of based on model-independent
analysis which includes twelve independent four Fermi operators. The CP
asymmetry is suppressed in the Standard Model, however, if some new physics
make it much larger, the present or the next generation B factories may catch
the CP violation in this decay mode. In this paper, we studied the correlation
of the asymmetry and the branching ratio, and then we will find only a type of
interactions can be enlarge the asymmetry. Therefore, in comparison with
experiments, we have possibility that we can constrain models beyond the
standard model.Comment: 12 pages, 5 figures, LaTeX, Accepted for Physical Review
The possible - mixing in QCD sum rules
We calculate the on-shell - mixing parameter with
the method of QCD sum rule. Our result is MeV. The electromagnetic interaction is not included
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