137 research outputs found

    From bubbles to foam: dilute to dense evolution of hadronic wave function at high energy

    Get PDF
    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

    Get PDF
    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

    Full text link
    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

    Full text link
    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 tt 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

    Full text link
    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 0.40.4%{}. 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

    Get PDF
    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

    Full text link
    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 10710^{-7}.Comment: 7 page

    Роль кальций-pH-зависимых механизмов в патогенезе воспалительных заболеваний пародонта

    Get PDF
    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

    Full text link
    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

    Get PDF
    Among the dipole models of deep inelastic scattering at small values of the Bjorken variable xx, 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 epep 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
    corecore