Spatial separation of large dynamical blue shift and harmonic generation

We study the temporal and spatial dynamics of the large amplitude and frequency modulation that can be induced in an intense, few cycle laser pulse as it propagates through a rapidly ionizing gas. Our calculations include both single atom and macroscopic interactions between the non-linear medium and the laser field. We analyze the harmonic generation by such pulses and show that it is spatially separated from the ionization dynamics which produce a large dynamical blue shift of the laser pulse. This means that small changes in the initial laser focusing conditions can lead to large differences in the laser frequency modulation, even though the generated harmonic spectrum remains essentially unchanged.Comment: 4 pages, 5 figures. Under revisio

Four-gap glass RPC as a candidate to a large area thin time-of-flight detector

A four-gap glass RPC with 0.3mm gap size was tested with hadron beam as a time-of-flight detector having a time resolution of ~ 100ps. A thickness of the detector together with front-end electronics is ~ 12mm. Results on time resolution dependently on a pad size are presented. This paper contains first result on the timing RPC (with ~ 100ps resolution) having a strip read-out. Study has been done within the HARP experiment (CERN-PS214) R&D work. A obtaned data can be useful if a design of a large area thin timing detector has to be done.Comment: 18 pages, 13 figure

Comparison of Geant4 hadron generation with data from the interactions with beryllium nuclei of +8.9 GeV/c protons and pions, and of -8 GeV/c pions

Hadron generation in the Geant4 simulation tool kit is compared with inclusive spectra of secondary protons and pions from the interactions with beryllium nuclei of +8.9 GeV/c protons and pions, and of -8.0 GeV/c pions. The data were taken in 2002 at the CERN Proton Synchrotron with the HARP spectrometer. We report on significant disagreements between data and simulated data especially in the polar-angle distributions of secondary protons and pions.Comment: 15 pages, 13 figure

Cross-sections of large-angle hadron production in proton-- and pion--nucleus interactions VIII: aluminium nuclei and beam momenta from {\pm}3 GeV/c to {\pm}15 GeV/c

We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% {\lambda}int thick stationary aluminium target, of proton and pion beams with momentum from \pm3 GeV/c to \pm15 GeV/c. Results are given for secondary particles with production angles between 20 and 125 degrees. Cross-sections on aluminium nuclei are compared with cross-sections on beryllium, carbon, copper, tin, tantalum and lead nuclei.Comment: 71 pages, 16 figures, 47 table

Classical Effects of Laser Pulse Duration on Strong-field Double Ionization

We use classical electron ensembles and the aligned-electron approximation to examine the effect of laser pulse duration on the dynamics of strong-field double ionization. We cover the range of intensities $10^{14}-10^{16} W/cm^2$ for the laser wavelength 780 nm. The classical scenario suggests that the highest rate of recollision occurs early in the pulse and promotes double ionization production in few-cycle pulses. In addition, the purely classical ensemble calculation predicts an exponentially decreasing recollision rate with each subsequent half cycle. We confirm the exponential behavior by trajectory back-analysis

Neutrino Induced Charged Current 1π+\pi^+ Production At Intermediate Energies

The charged current one pion production induced by $\nu_\mu$ from nucleons and nuclei like $^{12}$C and $^{16}$O nuclei has been studied. The calculations have been done for the incoherent and the coherent processes from nuclear targets assuming the $\Delta$ dominance model and take into account the effect of Pauli blocking, Fermi motion of the nucleon and renormalization of $\Delta$ properties in a nuclear medium. The effect of final state interactions of pions has been taken into account. The theoretical uncertainty in the total cross sections due to various parameterizations of the weak transition form factors used in literature has been studied. The numerical results for the total cross sections are compared with the recent preliminary results from the MiniBooNE collaboration on $^{12}$C and could be useful in analyzing future data from the K2K collaboration.Comment: 10 pages, 6 figures, 1 tabl