It has recently been suggested that the formation of horizon-size primordial black hole (PBH) from pre-existing density fluctuations is effective during the cosmic QCD phase transition. In this Letter we discuss the dependence of PBH formation on effective relativistic degrees of freedom, geff during the cosmic QCD phase transition. Our finding is important in the light of recent cosmological a...

Control of microbunching instability is a fundamental requirement in modern high brightness electron linacs, in order to prevent malfunction of beam optical diagnostics and contamination in the generation of coherent radiation, such as free electron lasers. We present experimental control and suppression of microbunching instabilityinduced optical transition radiation by means of particles’ lon...

We describe a new measurement of the intensities of the heavy primary cosmic-ray nuclei O, Ne, Mg, Si, and Fe from 10 GeV amu 1 to energies beyond 1 TeV amu 1. The measurement was conducted in 1999 during a 1 day test flight of the Transition Radiation Array for Cosmic Energetic Radiation (TRACER), a new cosmic-ray telescope designed for long-duration balloon flights. TRACER uses an array of th...

The PEGASUS Photoinjector has been commissioned at UCLA. The Plane Wave Transformer Photoinjector provides a high-brightness 17 MeV beam that will be used for numerous beam-radiation studies. Some of these will include SASE FEL, transition radiation from non-standard surfaces, and monochromatic x-ray production via PXR and Thompson scattering.

The (σ, ω) model in mean-field approximation where the meson fields are treated classically, describes much of observed nuclear structure and has been employed to describe the nuclear equation of state up to the quark-gluon phase transition. The acceleration of the meson sources, for example, in relativistic heavy-ion collisions, should result in bremsstrahlung-like radiation of the meson field...

Little is known about the effects of ionizing radiation on the transition and the related signal transduction of progenitor B cells in the bone marrow. Thus, using an NIH Swiss mouse model, we explored the impact of ionizing radiation on the early stage of B-cell development via an examination of the transition of CLP to pro-B to pre-B cells within bone marrow as a function of radiation doses a...

Digital Subtractive Angiography (DSA) has been performed to image human coronary arteries using wiggler radiation from electron storage rings. The significant medical promise of this procedure motivates the development of smaller and less costly x-ray sources. Several exotic sources are candidates for consideration, using effects such as Cherenkov, channeling, coherent bremsstrahlung, laser bac...

We give a comprehensive analysis of how scalar and tensor perturbations evolve in cosmologies with a smooth transition from power-law-like and de Sitter-like inflation to a radiation era. Analytic forms for the super-horizon and sub-horizon perturbations in the inflationary and radiation dominated eras are found.

Coherent transition radiation (CTR) was used to study the longitudinal modulations of an electron beam exiting the UCLA/LANL high gain SASE FEL. The induced longitudinal micro-bunching of the electron beam at the exit of the undulator was measured with a frequency domain technique using the CTR emitted when this beam strikes a thin conducting foil. Formalisms for both CTR and SASE theories are ...