Investigation of warm fog properties and fog modification concepts Annual summary report

Ground based and aerial seeding of warm fog with hygroscopic materials and computer modeling of fog response to seedin

Project Fog Drops 5. Task 1: A numerical model of advection fog. Task 2: Recommendations for simplified individual zero-gravity cloud physics experiments

A two-dimensional numerical model was used to investigate the formation of marine advection fog. The model predicts the evolution of potential temperature, horizontal wind, water vapor content, and liquid water content in a vertical cross section of the atmosphere as determined by vertical turbulent transfer and horizontal advection, as well as radiative cooling and drop sedimentation. The model is designed to simulate the formation, development, or dissipation of advection fog in response to transfer of heat and moisture between the atmosphere and the surface as driven by advection over horizontal discontinuities in the surface temperature. Results from numerical simulations of advection fog formation are discussed with reference to observations of marine fog. A survey of candidate fog or cloud microphysics experiments which might be performed in the low gravity environment of a shuttle-type spacecraft in presented. Recommendations are given for relatively simple experiments which are relevent to fog modification problems

Statistical uncertainty in quantum optical photodetection measurements

We present a complete statistical analysis of quantum optical measurement schemes based on photodetection. Statistical distributions of quantum observables determined from a finite number of experimental runs are characterized with the help of the generating function, which we derive using the exact statistical description of raw experimental outcomes. We use the developed formalism to point out that the statistical uncertainty results in substantial limitations of the determined information on the quantum state: though a family of observables characterizing the quantum state can be safely evaluated from experimental data, its further use to obtain the expectation value of some operators generates exploding statistical errors. These issues are discussed using the example of phase-insensitive measurements of a single light mode. We study reconstruction of the photon number distribution from photon counting and random phase homodyne detection. We show that utilization of the reconstructed distribution to evaluate a simple well-behaved observable, namely the parity operator, encounters difficulties due to accumulation of statistical errors. As the parity operator yields the Wigner function at the phase space origin, this example also demonstrates that transformation between various experimentally determined representations of the quantum state is a quite delicate matter.Comment: 18 pages REVTeX, 7 figures included using epsf. Few minor corrections made, clarified conclusion

Identification of indirect new physics effects at e^+e^- colliders: the large extra dimensions case

We discuss indirect manifestations of graviton exchange, predicted by large extra dimensions, in fermion-pair production at a high-energy e^+e^- collider. By means of specifically defined asymmetries among integrated angular distributions, the graviton exchange signal can be cleanly distinguished from the effects of either vector-vector contact interactions or heavy scalar exchanges. The role of initial electron and positron beams polarization is also discussed. The method is applied to a quantitative assessment of the sensitivity to the mass cut-off parameter M_H of the KK graviton tower in the ADD scenario, and of the potential identification reach of this mechanism obtainable at the currently planned Linear Collider.Comment: 21 pages, 11 figure

Investigation of warm fog properties and fog modification concepts

Warm fog seeding to determine potential of various sized and unsized hygroscopic chemicals for fog dissipatio

Z' signal from the LEP2 data

The many-parametric fit of the LEP2 data on e^+e^-\to e^+e^-, \mu^+\mu^-, \tau^+\tau^- processes is performed to estimate signals of the Abelian Z'-boson beyond the standard model. The model-independent relations between the Z' couplings to the standard model particles allow to describe the Z' effects in lepton processes by 4 independent parameters. No signal is found by the complete LEP2 data set, and the 1.3\sigma signal is detected by the fit of the backward bins. The Z' couplings to the vector and axial-vector lepton currents are constrained. The comparisons with the one-parameter fits and with the LEP1 experiments are performed.Comment: 6 pages, 2 figures, RevTeX. The paper was completely rewritten. The errors in the first version were eliminated. The comparison with the LEP1 data is adde

Globular Cluster Systems in Brightest Cluster Galaxies. III: Beyond Bimodality

We present new deep photometry of the rich globular cluster (GC) systems around the Brightest Cluster Galaxies UGC 9799 (Abell 2052) and UGC 10143 (Abell 2147), obtained with the HST ACS and WFC3 cameras. For comparison, we also present new reductions of similar HST/ACS data for the Coma supergiants NGC 4874 and 4889. All four of these galaxies have huge cluster populations (to the radial limits of our data, comprising from 12000 to 23000 clusters per galaxy). The metallicity distribution functions (MDFs) of the GCs can still be matched by a bimodal-Gaussian form where the metal-rich and metal-poor modes are separated by ~0.8 dex, but the internal dispersions of each mode are so large that the total MDF becomes very broad and nearly continuous from [Fe/H] = -2.4 to Solar. There are, however, significant differences between galaxies in the relative numbers of \emph{metal-rich} clusters, suggesting that they underwent significantly different histories of mergers with massive, gas-rich halos. Lastly, the proportion of metal-poor GCs rises especially rapidly outside projected radii R > 4 R_eff, suggesting the importance of accreted dwarf satellites in the outer halo. Comprehensive models for the formation of GCs as part of the hierarchical formation of their parent galaxies will be needed to trace the systematic change in structure of the MDF with galaxy mass, from the distinctly bimodal form in smaller galaxies up to the broad continuum that we see in the very largest systems.Comment: In press for Astrophysical Journa