181 research outputs found
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 . 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- 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
Scale Factor in Double Parton Collisions and Parton Densities in Transverse Space
The scale factor , 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 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
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
Radiative Ke3 decays revisited
Motivated by recent experimental results and ongoing measurements, we review
the chiral perturbation theory prediction for radiative Ke3 decays (neutral
kaons). Special emphasis is given on the stability of the inner
bremsstrahlung-dominated relative branching ratio vs. the Ke3 form factors, and
on the separation of the structure dependent amplitude in differential
distributions over the phase space. For the structure dependent terms, an
assessment of the order p^6 corrections is given. In particular, a full
next-to-leading order calculation of the axial component is performed. The
experimental analysis of the photon energy spectrum is discussed, and other
potentially useful distributions are introduced.Comment: Version published in Eur.Phys.J.C.: 23 pages (LaTeX), 10 figures.
Minor changes in text, typos removed, references updated, Springer style file
use
Double parton distributions in the leading logarithm approximation of perturbative QCD
Recent CDF measurements of the inclusive cross section for a double parton
scattering attach a great importance to any theoretical calculations of
two-particle distribution functions. Using a parton interpretation of the
leading logarithm diagrams of perturbative QCD theory, generalized
Lipatov-Altarelli-Parisi-Dokshitzer equations for the two-parton distributions
are re-obtained. The solutions of these equations are not at all the product of
two single-parton distributions what is usually applied to the current analysis
as ansatz.Comment: 8 pages, LaTe
``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
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
Strong rescattering in K-> 3pi decays and low-energy meson dynamics
We present a consistent analysis of final state interactions in
decays in the framework of Chiral Perturbation Theory.
The result is that the kinematical dependence of the rescattering phases cannot
be neglected. The possibility of extracting the phase shifts from future
interference experiments is also analyzed.Comment: 14 pages in RevTex, 3 figures in postscrip
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