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Milos Lokajicek

Publications and source records attributed to Milos Lokajicek.

8 recordsLinked to original sources

Research and Development for Near Detector Systems Towards Long Term Evolution of Ultra-precise Long-baseline Neutrino Experiments

With the discovery of non-zero value of $θ_{13}$ mixing angle, the next generation of long-baseline neutrino (LBN) experiments offers the possibility of obtaining statistically significant samples of muon and electron neutrinos and anti-neutrinos with large oscillation effects. In this document we intend to highlight the importance of Near Detector facilities in LBN experiments to both constrain the systematic uncertainties affecting oscillation analyses but also to perform, thanks to their close location, measurements of broad benefit for LBN physics goals. A strong European contribution to these efforts is possible.

physics.ins-det

Theoretical aspects of high energy elastic nucleon scattering

The eikonal model must be denoted as strongly preferable for the analysis of elastic high-energy hadron collisions. The given approach allows to derive corresponding impact parameter profiles that characterize important physical features of nucleon collisions, e.g., the range of different forces. The contemporary phenomenological analysis of experimental data is, however, not able to determine these profiles unambiguously, i.e., it cannot give the answer whether the elastic hadron collisions are more central or more peripheral than the inelastic ones. However, in the collisions of mass objects (like protons) the peripheral behavior of elastic collisions should be preferred.

hep-ph

Contemporary models of elastic nucleon scattering and their predictions for LHC

The analyses of elastic collisions of charged nucleons have been based standardly on West and Yennie formula. However, this approach has been shown recently to be inadequate from experimental as well as theoretical points of view. The eikonal model seems to be more pertinent as it enables to determine physical characteristics in impact parameter space. The contemporary phenomenological models cannot give, of course, any definite answer as the elastic collisions may be interpreted differently, as central or peripheral processes. Nevertheless, the predictions for the planned LHC energy have been given on their basis and the possibility of exact determination of luminosity has been considered.

hep-ph

To the theory of high-energy elastic nucleon collisions

The commonly used West and Yennie integral formula for the relative phase between the Coulomb and elastic hadronic amplitudes requires for the phase of the elastic hadronic amplitude to be constant at all kinematically allowed values of t. More general interference formula based on the eikonal model approach does not exhibit such limitation. The corresponding differences will be demonstrated and some predictions of different phenomenological models for elastic pp scattering at energy of 14 TeV at the LHC will be given. Special attention will be devoted to determination of luminosity from elastic scattering data; it will be shown that the systematic error might reach till 5 % if the luminosity is derived from the values in the center of the interference region with the help of West and Yennie formula.

hep-ph

Modelling the mechanism of cell inactivation by light ions at different energy values

For efficient application of protons and light ions in radiotherapy, detailed knowledge and realistic models of the corresponding radiobiological mechanism are necessary. Basic characteristics of this mechanism have been represented within a probabilistic two-stage model. The processes that occur immediately after the traversals of individual particles and the response of cell to the total damage formed by all the particles have been distinguished. The model involves a probabilistic description of DNA damage formation and repair processes, too.

physics.bio-ph

Cell inactivation by diverse ions along their tracks

Irradiation of cell monolayers by monoenergetic ions has made it possible to establish survival curves at individual values of linear energy transfer. The two-step model of radiobiological mechanism proposed recently by Judas and Lokajicek (Judas L., Lokajicek M., 2001: Cell inactivation by ionizing particles and the shapes of survival curves. J. Theor. Biol. 210 (1), 15-21., doi:10.1006/jtbi.2001.2283) has then enabled to show that some significant deviations from the generally used linear-quadratic model should exist at higher values of linear energy transfer, which has been also demonstrated experimentally. However, the new model has been expressed in the form being applicable rightfully to low-dose parts of survival curves only. It has been now reformulated to be applicable in analyses of whole survival curves. Inactivation probabilities after different numbers of particles traversing cell nuclei (chromosomal systems) may be then derived from experimental data. Analyses of published data obtained in irradiating by protons and deuterons will be presented and discussed.

physics.med-ph

High-energy elastic hadron collisions and space structure of hadrons

The elastic and inelastic profiles have been derived from the measured elastic differential cross section data with the help of exact impact parameter representation of elastic scattering amplitude. The results obtained for $pp$ scattering at energy of 53 GeV and $\bar{p} p$ scattering at energy of 541 GeV have been presented. They indicate that nucleons can be regarded as objects characterized by a small core (diameter $\sim$ 0.4$÷$0.8 fm) and a half transparent outer shell (responsible mainly for elastic hadron scattering).

hep-ph