137 research outputs found
From bubbles to foam: dilute to dense evolution of hadronic wave function at high energy
We derive the evolution of a hadronic light cone wave function with energy at
weak coupling. Our derivation is valid both in the high and the low partonic
density limit, and thus encompasses both the JIMWLK and the KLWMIJ evolution.
The hadronic wave function is shown to evolve by the action of the
Bogoliubov-type operator, which diagonalizes on the soft gluon sector the
light-cone hamiltonian in the presence of an arbitrary valence charge density.
We find explicitly the action of this operator on the soft as well as the
valence degrees of freedom of the theory.Comment: 30 page
Pomeron loop and running coupling effects in high energy QCD evolution
Within the framework of a (1+1)-dimensional model which mimics evolution and
scattering in QCD at high energy, we study the influence of the running of the
coupling on the high-energy dynamics with Pomeron loops. We find that the
particle number fluctuations are strongly suppressed by the running of the
coupling, by at least one order of magnitude as compared to the case of a fixed
coupling, for all the rapidities that we have investigated, up to Y=200. This
reflects the slowing down of the evolution by running coupling effects, in
particular, the large rapidity evolution which is required for the formation of
the saturation front via diffusion. We conclude that, for all energies of
interest, processes like deep inelastic scattering or forward particle
production can be reliably studied within the framework of a mean-field
approximation (like the Balitsky-Kovchegov equation) which includes running
coupling effects.Comment: 23 pages, 8 figure
On the role of longitudinal momenta in high energy hadron-hadron scattering
We demonstrate a new method for the calculation of inelastic scattering
cross-section, which in contrary to the Regge-based methods takes into account
the energy momentum conservation law. By virtue of this method it was shown
that the main contribution to integral expressing inelastic scattering
cross-sections comes not from the multi-Regge domain. In particular this leads
to the fact that accounting of longitudinal momenta contribution to
virtualities is sufficient and results in the new mechanism of cross-section
growth. The necessity of taking into account the large number of interference
contributions is shown and the approximate method for this purpose is
developed. By considering the interference contributions from a single fitting
constant achieved a qualitative agreement of the total and inelastic cross
sections with experimental data.Comment: 38 pages, 19 figures (A misspelled author's name corrected
A QCD motivated model for soft interactions at high energies
In this paper we develop an approach to soft scattering processes at high
energies,which is based on two mechanisms: Good-Walker mechanism for low mass
diffractionand multi-Pomeron interactions for high mass diffraction. The
pricipal idea, that allows us to specify the theory for Pomeron interactions,
is that the so called soft processes occur at rather short distances
(r^2 \propto 1 /^2 \propto \alpha'_\pom \approx 0.01 GeV^{-2}), where
perturbative QCD is valid. The value of the Pomeron slope \alpha'_\pom was
obtained from the fit to experimental data. Using this theoretical approach we
suggest a model that fits all soft data in the ISR-Tevatron energy range, the
total, elastic, single and double diffractive cross sections, including
dependence of the differential elastic cross section, and the mass dependence
of single diffraction. In this model we calculate the survival probability of
diffractive Higgs production, and obtained a value for this observable, which
is smaller than 1% at the LHC energy range.Comment: 33pp,20 figures in eps file
Survival probability in diffractive Higgs production in high density QCD
In this paper, the contribution of hard processes described by the BFKL
pomeron exchange, is taken into account by calculating the first enhanced
diagram. The survival probability is estimated, using the ratio of the first
enhanced diagram and the single pomeron amplitude, taking into account all
essential pomeron loop diagrams in the toy model of Mueller. The triple pomeron
vertex is calculated explicitly in the momentum representation. This
calculation is used for estimating the survival probability, It turns out that
the survival probability is small, at . Hard pomeron re-scattering
processes contribute substantially to the survival probability.Comment: 28 pages, 7 figure
Measurement of the 6s - 7p transition probabilities in atomic cesium and a revised value for the weak charge Q_W
We have measured the 6s - 7p_{1/2,3/2} transition probabilities in atomic
cesium using a direct absorption technique. We use our result plus other
previously measured transition rates to derive an accurate value of the vector
transition polarizability \beta and, consequently, re-evaluate the weak charge
Q_W. Our derived value Q_W=-72.65(49) agrees with the prediction of the
standard model to within one standard deviation.Comment: 4 pages, 2 figure
Accurate spline solutions of the Dirac equation with parity-nonconserving potential
The complete system of the B-spline solutions for the Dirac equation with the
parity-nonconserving (PNC) weak interaction effective potential is obtained.
This system can be used for the accurate evaluation of the radiative
corrections to the PNC amplitudes in the multicharged ions and neutral atoms.
The use of the scaling procedure allows for the evaluation of the PNC matrix
elements with relative accuracy .Comment: 7 page
Роль кальций-pH-зависимых механизмов в патогенезе воспалительных заболеваний пародонта
Comparative investigation of dynamics of pH, concentration of calcium and inorganic phosphate in mixtured saliva during testing loads in patients with healthy periodontium, susceptible to caries and with combination of caries with inflammatory periodontal diseases was performed. Close dependency between dynamics of researched parameters was revealed during sugar and urea loads as well. Inorganic phosphate disgomeostasis, role in pathogenesis of inflammatory periodontal diseases was showed.Проведено сравнительное исследование динамики рН, концентрации кальция и неорганического фосфата в смешанной слюне при тестовых нагрузках у лиц со здоровым пародонтом, кариесвоспримчивых и с сочетанием кариеса и воспалительных заболеваний пародонта. Выявлена тесная взаимосвязь динамики изучаемых параметров как при сахарной, так и при карбамидной нагрузках. Показана роль дисгомеостаза неорганического фосфата в патогенезе воспалительных заболеваний пародонта
Regge Field Theory in zero transverse dimensions: loops versus "net" diagrams
Toy models of interacting Pomerons with triple and quaternary Pomeron
vertices in zero transverse dimension are investigated. Numerical solutions for
eigenvalues and eigenfunctions of the corresponding Hamiltonians are obtained,
providing the quantum solution for the scattering amplitude in both models. The
equations of motion for the Lagrangians of the theories are also considered and
the classical solutions of the equations are found. Full two-point Green
functions ("effective" Pomeron propagator) and amplitude of diffractive
dissociation process are calculated in the framework of RFT-0 approach. The
importance of the loops contribution in the amplitude at different values of
the model parameters is discussed as well as the difference between the models
with and without quaternary Pomeron vertex.Comment: 34 pages, 36 figure
DIS and the effects of fluctuations: a momentum space analysis
Among the dipole models of deep inelastic scattering at small values of the
Bjorken variable , one has been recently proposed which relates the virtual
photon-proton cross section to the dipole-proton forward scattering amplitude
in momentum space. The latter is parametrized by an expression which
interpolates between its behavior at saturation and the travelling wave,
ultraviolet, amplitudes predicted by perturbative QCD from the
Balitsky-Kovchegov equation. Inspired by recent developments in coordinate
space, we use this model to parametrize the proton structure function and
confront it to HERA data on deep inelastic scattering. Both event-by-event
and the physical amplitudes are considered, the latter used to investigate the
effect of gluon number fluctuations, beyond the mean-field approximation. We
conclude that fluctuations are not present in DIS at HERA energies.Comment: 9 pages, 2 figure
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