Influence of the beam-size or MD-effect on particle losses at B-factories PEP-II and KEKB

For the $e^+ e^- \to e^+ e^- \gamma$ process at colliding beams, macroscopically large impact parameters give an essential contribution to the standard cross section. These impact parameters may be much larger than the transverse sizes of the colliding bunches. It means that the standard calculations have to be essentially modify. In the present paper such a beam-size or MD-effect is calculated for bremsstrahlung at B-factories PEP-II and KEKB using the list of nominal parameters from Review of Particle Physics (2002). We find out that this effect reduces beam losses due to bremsstrahlung by about 20%.Comment: 10 Latex page

Beam-size effect and particle losses at SuperBB factory (Italy)

In the colliders, the macroscopically large impact parameters give a substantial contribution to the standard cross section of the $e^+ e^- \to e^+ e^- \gamma$ process. These impact parameters may be much larger than the transverse sizes of the colliding bunches. It means that the standard cross section of this process has to be substantially modified. In the present paper such a beam-size effect is calculated for bremsstrahlung at Super$B$ factory developed in Italy. We find out that this effect reduces beam losses due to bremsstrahlung by about 40%.Comment: 11 pages, 4 figure

The Third California: The Golden State's New Frontier

Documents the new movement of people and jobs to the interior region of the state, and discusses the broad implications of these changes for California as well as other Western states

Effective photon spectra for Photon Colliders

The luminosity distribution in the effective $\gamma\gamma$ mass at photon collider has usually two peaks which are well separated: high energy peak with mean energy spread 5-7% and wide low energy peak.The low energy peak depends strongly on details of design it is unsuitablefor the study of New Physics phenomena. We find simple approximte form of spectra of collided photons for $\gamma\gamma$ and $e\gamma$ colliders wich convolution describes high energy luminosity peak with good accuracy in the most essential preferable region of parameters.Comment: 8 Latex page, 9 eps figur

Polarization of high-energy electrons traversing a laser beam

When polarized electrons traverse a region where the laser light is focused their polarization varies even if their energy and direction of motion are not changed. This effect is due to interference of the incoming electron wave and an electron wave scattered at zero angle. Equations are obtained which determine the variation of the electron density matrix, and their solutions are given. The change in the electron polarization depends not only on the Compton cross section but on the real part of the forward Compton amplitude as well. It should be taken into account, for example, in simulations of the $e \to \gamma$ conversion for future $\gamma \gamma$ colliders.Comment: 11 pages, LaTeX , 2 postscript figures include

Deviation from standard QED at large distances: influence of transverse dimensions of colliding beams on bremsstrahlung

The radiation at collision of high-energy particles is formed over a rather long distances and therefore is sensitive to an environment. In particular the smallness of the transverse dimensions of the colliding beams leads to suppression of bremsstrahlung cross section for soft photons. This beam-size effect was discovered and investigated at INP, Novosibirsk around 1980. At that time an incomplete expression for the bremsstrahlung spectrum was calculated and used because a subtraction associated with the extraction of pure fluctuation process was not performed. Here this procedure is done. The complete expression for the spectral-angular distribution of incoherent bremsstrahlung probability is obtained. The case of Gaussian colliding beams is investigated in details. In the case of flat beams the expressions for the bremsstrahlung spectrum are simplified essentially. Comparison of theory with VEPP4 and HERA data is performed. Possible application of the effect to linear $e^+e^-$ collider tuning is discussed.Comment: 23 pagers,5 figure

Observation of the beam-size effect at HERA

A precise measurement of the spectrum of the photons from $ep$ bremsstrahlung with the ZEUS luminosity monitor at HERA is reported. The measurement shows a reduced rate compared to the Bethe-Heitler spectrum for photon energies below 5~GeV. This suppression, called the beam-size effect, is explained by the finite transverse size of the beam overlap relative to the typical impact parameter in the process of $ep$ bremsstrahlung at HERA energies.Comment: 12 pages, late

Inverse Nonlinear Programming Problem and its Application

Inverse nonlinear programming problems for a new class of optimization problems relevant for game theory, system optimization, multicriteria optimization, etc. are considered by the author. This paper deals with problem definitions, numerical methods and applications of the inverse nonlinear programming problem in multicriteria optimization. Some associated properties of related parametric optimization problems and software implementations are also considered

Geometric Ideas in Nonlinear and Multicriteria Optimization

Some geometric properties of the solution set for nonlinear and multicriteria programming problems and the related numeric algorithms are considered. The author deals with necessary and sufficient conditions for nonlinear programming problem stability (in the nonconvex case), with Pareto set stability, Pareto set connectedness conditions, with weak efficiency, efficiency and proper efficiency criteria. A study of numerical algorithms based on geometric properties of the so-called convolutions function is also considered. Necessary and sufficient convergence conditions for large classes of algorithms are presented and easy to check sufficient conditions are given. Further results deal with problems of using local unconstrained minimization algorithms to solve quasi-convex problems and the problem of using some convolution functions for constructing decision making procedures. New classes of inverse nonlinear programming problems are discussed and software implementations of DISO/PC-MCNLP are presented