Pion-Muon Asymmetry Revisited

Long ago an unexpected and unexplainable phenomena was observed. The distribution of muons from positive pion decay at rest was anisotropic with an excess in the backward direction relative to the direction of the proton beam from which the pions were created. Although this effect was observed by several different groups with pions produced by different means, the result was not accepted by the physics community, because it is in direct conflict with a large set of other experiments indicating that the pion is a pseudoscalar particle. It is possible to satisfy both sets of experiments if helicity-zero vector particles exist and the pion is such a particle. Helicity-zero vector particles have direction but no net spin. For the neutral pion to be a vector particle requires an additional modification to conventional theory as discussed herein. An experiment is proposed which can prove that the asymmetry in the distribution of muons from pion decay is a genuine physical effect because the asymmetry can be modified in a controllable manner. A positive result will also prove that the pion is NOT a pseudoscalar particle.Comment: 9 pages, 3 figure

Recent Advances in Understanding Particle Acceleration Processes in Solar Flares

We review basic theoretical concepts in particle acceleration, with particular emphasis on processes likely to occur in regions of magnetic reconnection. Several new developments are discussed, including detailed studies of reconnection in three-dimensional magnetic field configurations (e.g., current sheets, collapsing traps, separatrix regions) and stochastic acceleration in a turbulent environment. Fluid, test-particle, and particle-in-cell approaches are used and results compared. While these studies show considerable promise in accounting for the various observational manifestations of solar flares, they are limited by a number of factors, mostly relating to available computational power. Not the least of these issues is the need to explicitly incorporate the electrodynamic feedback of the accelerated particles themselves on the environment in which they are accelerated. A brief prognosis for future advancement is offered.Comment: This is a chapter in a monograph on the physics of solar flares, inspired by RHESSI observations. The individual articles are to appear in Space Science Reviews (2011

Cytochrome d induction in Escherichia coli growing under unfavorable conditions

AbstractGrowth of E. Coli in the presence of the protonophorous uncoupler pentachlorophenol is shown to strongly enhance levels of cytochrome d, a putative Na+-motive oxidase. This effect was found to be arrested by chloramphenicol and stimulated by high Na+ concentration in the growth medium. The induction of cytochrome d takes place in a mutant deficient in the F0F1 ATP-synthase but does not occur in mutants deficient in either of two different components of the Arc system. Similar relationships were revealed when pentachlorophenol was replaced by ferricyanide and phenazine methosulfate, agents oxidizing the respiratory chain. Induction of cytochrome d is also shown to occur in riboflavin-deficient mutants growing in the presence of such low riboflavin concentrations as to be insufficient to maintain a high respiration rate. It is suggested (i) that it is Δ−μH+ decrease rather than reduction of the respiratory chain that is the signal for the induction of cytochrome d, and (ii) the Arc system is involved in this type of metabolic regulation

Topological Spaces with Skorokhod Representation Property

We give a survey of recent results that generalize and develop a classical theorem of Skorokhod on representation of weakly convergent sequences of probability measures by almost everywhere convergent sequences of mappings.Наведено огляд отриманих останнім часом результатів, що узагальнюють класичну теорему Скорохода про зображення слабко збіжної послідовності ймовірнісних мір майже напевно збіжними послідовностями відображень

Evidence of quasifission in the 180Hg composite system formed in the 68Zn + 112Sn reaction

For the 68Zn + 112Sn reaction the Coulomb parameter Z1Z2 is equal to 1500 that is close to the threshold value for the appearance of quasifission process. It was found that mass-energy distributions of the reaction fragments differ significantly from those obtained in the 36Ar + 144Sm reaction leading to the formation of the same composite system of 180Hg at similar excitation energies of about 50 MeV. In the case of the reaction with 68Zn ions, the mass distribution of fissionlike fragments has a wide two-humped shape with maximum yields at 70 and 110 u for the light and heavy fragments, respectively, instead of 80 and 100 u observed in the fission of 180Hg formed in the 36Ar + 144Sm reaction. The difference is explained by an unexpectedly large contribution (more than 70%) of quasifission in the case of the 68Zn + 112Sn reaction.peerReviewe