Coulomb—Born—Oppenheimer approximation in Ps—H scattering

To improve the Coulomb-Born approximation (CBA) theory of ionization in positronium (Ps) and atom scattering, the effect of exchange is introduced. The nine-dimensional exchange amplitude for ionization of Ps in Ps—H scattering is reduced to a two-dimensional integral using the present Coulomb-Born-Oppenheimer approximation (CBOA). The methodology is extremely useful to evaluate ionization parameters for different target systems and for different types of ionization processes. It is then applied to evaluate the Ps-ionization cross-section and to estimate the effect of exchange on Psionization in Ps-H system. We establish the importance of exchange at lower energy region.     

A NEW CHARACTERIZATION OF Qp^# FUNCTIONS

A new characterization of Q#p is given, which implies immediately a known result. Also, the authors consider a class Np of bounded characteristic with order p, 0 < p < ∞, in the unit disk and give some relationship between it and other classes of meromorphic functions. This paper answers partly a question mentioned by Aulaskari and Lappan.     

The TOTEM experiment

The European Physical Journal C - TOTEM will measure the total pp cross-section at LHC by using a luminosity independent method based on simultaneous evaluation of the total elastic and inelastic...     

The effects of medium phonon lifetime on pulse compression ratio in the process of stimulated Brillouin scattering

The performances of stimulated Brillouin scattering (SBS) media with short phonon lifetimes on temporal compression are studied in this paper. In the experiment, FC-72, HT-135 and FC-40 (phonon lifetimes are 1.2 ns, 0.4 ns and 0.2 ns, respectively) are used to study the influence of phonon lifetime on pulse compression in a compact two-cell SBS system. High pulse compression ratio is obtained by a medium with a short phonon lifetime when input energy is high. These results are useful in the generation of picoseconds pulse for Shock Ignition of thermonuclear fuel for ICF.     

Investigation on pulse compression based on stimulated Brillouin scattering and optical breakdown

Pulse compression based on the combination of stimulated Brillouin scattering (SBS) and optical breakdown is investigated in this paper. The first pulse compression based on SBS features a sharp rising edge while the second based on optical breakdown is characterized by a sharp falling edge, therefore a symmetrical narrow pulse can be produced with this approach. In the experiment, FC-72 is used as the Brillouin medium in the first pulse compression, while HT-270 is chosen as the solvent for optical breakdown in the second pulse compression. A 12-ns pump pulse is first compressed to 6 ns by SBS and then further to about 2 ns with comparatively symmetrical edges after optical breakdown.     

Measurement of intrinsic Brillouin linewidth of fibers based on stimulated Brillouin scattering slow light

Intrinsic Brillouin linewidth is one of the essential parameters to optimize the gain spectrum of stimulated Brillouin scattering (SBS). A novel method for the measurement of the intrinsic Brillouin line-width based on SBS slow light is proposed and demonstrated. In this method, an implicit model based on the transient SBS theory is developed, and a data processing method is designed to obtain the value of the intrinsic Brillouin linewidth from the model. The measured results show that the method is effective for studying SBS slow light.     

Compactness of composition operators on BMOA and VMOA

We give a new and simple compactness condition for composition operators on BMOA,the space of all analytic functions of the bounded mean oscillation on the unit disk.Using our results one may immediately obtain that compactness of a composition operator on BMOA implies its compactness on the Bloch space as well as on the Hardy space.Similar results on VMOA are also given.