2,539 research outputs found
How to measure the Pomeron phase in diffractive dipion photoproduction
The study of charge asymmetry of pions in the high-energy process gamma p ->
pi+ pi- p (e p -> e pi+ pi- p) at very small dipion momenta offers a method to
measure the phase of the forward hadronic (quasi)elastic amplitude gamma p ->
rho p. We estimate potential of such measurements at HERA.Comment: 12 pages, 2 figures; v4: more elaborate parametrizations of dipion
spectra implemented, discussion extende
CP odd anomalous interactions of Higgs boson in its production at Photon Colliders
We discuss the potentialities of the study of CP-odd interactions of the
Higgs boson with photons via its production at gamma-gamma and e-gamma
colliders. Our treatment of H-gamma-gamma and H-Z-gamma anomalous interactions
includes a set of parameters, whose impact on physical observables has not been
considered before. We focus on two reactions - gamma+gamma-->H and e+gamma-->eH
- and introduce the polarization and/or azimuthal asymmetries that are
particularly sensitive to specific features of anomalies. We discuss the ways
of disentangling effects of physically different parameters of anomalies and
estimate what magnitude of CP violating phenomena can be seen in these
experiments.Comment: 17 pages, 9 figs; some modifications in the results presentation;
version to be published in Eur.Phys.J.
Semiempirical methods for computing turbulent flows
Two semiempirical theories which provide a basis for determining the turbulent friction and heat exchange near a wall are presented: (1) the Prandtl-Karman theory, and (2) the theory utilizing an equation for the energy of turbulent pulsations. A comparison is made between exact numerical methods and approximate integral methods for computing the turbulent boundary layers in the presence of pressure, blowing, or suction gradients. Using the turbulent flow around a plate as an example, it is shown that, when computing turbulent flows with external turbulence, it is preferable to construct a turbulence model based on the equation for energy of turbulent pulsations
Single Leptoquark Production at and Colliders
We consider single production of leptoquarks (LQ's) at and
colliders, for two values of the centre-of-mass energy,
GeV and 1 TeV. We find that LQ's which couple within the first
generation are observable for LQ masses almost up to the kinematic limit, both
at and colliders, for the LQ coupling strength equal to
. The cross sections for single production of - and
-generation LQ's at colliders are too small to be observable.
In collisions, on the other hand, -generation LQ's with
masses much larger than can be detected. However,
-generation LQ's can be seen at colliders only for
masses at most , making their observation more probable via the
pair production mechanism.Comment: plain TeX, 14 pages, 6 figures (not included but available on
request), some minor changes to the text, one reference added, figures and
conclusions unchanged, UdeM-LPN-TH-93-152, McGill-93/2
Tree-level unitarity constraints in the most general 2HDM
We obtain tree-level unitarity constraints for the most general Two Higgs
Doublet Model (2HDM) with explicit CP-violation. We briefly discuss
correspondence between possible violation of tree level unitarity limitation
and physical content of the theory.Comment: 6 pages, no figure
The evolution of vacuum states and phase transitions in 2HDM during cooling of Universe
We consider the evolution of the ground state in the Two Higgs Doublet Model
during cooling down of the Universe after the Big Bang. Different regions in
the space of free parameters of this model correspond to different sequences of
thermal phase transitions. We discuss different paths of thermal evolution and
corresponding evolution of physical properties of the system for different
modern values of the parameters.Comment: 28 pages, 12 figure
Evolution of Universe to the present inert phase
We assume that current state of the Universe can be described by the Inert
Doublet Model, containing two scalar doublets, one of which is responsible for
EWSB and masses of particles and the second one having no couplings to fermions
and being responsible for dark matter. We consider possible evolutions of the
Universe to this state during cooling down of the Universe after inflation. We
found that in the past Universe could pass through phase states having no DM
candidate. In the evolution via such states in addition to a possible EWSB
phase transition (2-nd order) the Universe sustained one 1-st order phase
transition or two phase transitions of the 2-nd order.Comment: 19 pages, 3 figure
Possible Odderon discovery at HERA via charge asymmetry in the diffractive pi+pi- production
We discuss how the evasive Odderon signal can be enhanced by final state
interactions. We suggest the charge asymmetry of pion spectra in diffractive
pi+pi- photoproduction as a promising signature of the Odderon exchange.Comment: 4 pages, To appear in Proceedings of the 9th International Workshop
on Deep Inelastic Scattering (DIS2001), Bologna, Italy, 27 Apr. - 1 May 200
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