Photon Energy Spectrum in B→XsγB \to X_s \gamma and Comparison with Data

A comparison of the inclusive photon energy spectrum in the radiative decay \BGAMAXS, measured recently by the CLEO collaboration, with the standard model is presented, using a $B$-meson wave function model and improving earlier perturbative QCD-based computations of the same. The dependence of the photon energy spectrum on the non-perturbative model parameters, $p_F$, the $b$-quark Fermi momentum in the $B$ hadron, and $m_q$, the spectator quark mass, is explicitly shown, allowing a comparison of these parameters with the ones obtained from the analysis of the lepton energy spectrum in semileptonic $B$ decays. Taking into account present uncertainties, we estimate \BBGAMAXS = (2.55 \pm 1.28) \times 10^{-4} in the standard model, assuming \absvts/\absvcb= 1.0. Comparing this with the CLEO measurement \BBGAMAXS = (2.32 \pm 0.67) \times 10^{-4} implies \absvts/\absvcb= 1.1 \pm 0.43, in agreement with the CKM unitarity.Comment: 16 pages (including 5 Figures as encapsulated ps-files: use epsf and rotate

Efficient Generation of Model Bulk Heterojunction Morphologies for Organic Photovoltaic Device Modeling

Kinetic Monte Carlo (KMC) simulations have been previously used to model and understand a wide range of behaviors in bulk heterojunction (BHJ) organic photovoltaic devices, from fundamental mechanisms to full device performance. One particularly unique and valuable aspect of this type of modeling technique is the ability to explicitly implement models for the bicontinuous nanostructured morphology present in these devices. For this purpose, an Ising-based method for creating model BHJ morphologies has become prevalent. However, this technique can be computationally expensive, and a detailed characterization of this method has not yet been published. Here, we perform a thorough characterization of this method and describe how to efficiently generate controlled model BHJ morphologies. We show how the interaction energy affects the tortuosity of the interconnected domains and the resulting charge transport behavior in KMC simulations. We also demonstrate how to dramatically reduce calculation time by several orders of magnitude without detrimentally affecting the resulting morphologies. In the end, we propose standard conditions for generating model morphologies and introduce a new open-source software tool. These developments to the Ising method provide a strong foundation for future simulation and modeling of BHJ organic photovoltaic devices that will lead to a more detailed understanding of the important link between morphological features and device performance.Comment: Main article: 9 pages, 6 figures, Supplementary Information: 6 pages, 6 figure

Multi-State Logging Freeze Detection Passive RFID Tags

In this work the design and measurement of a passive UHF RFID smart tag suitable for monitoring and recording critical temperature violations in cold chain management are presented. The tag uses moving parts to detect and log different temperate states without the requirement for transceivers, memory and batteries. A simple mechanical method is proposed whereby a moving metallic plate is trapped in one of 4 possible positions by specific environmental temperatures whereby inducing a permanent state based change in the passive RFID tag response. The latched product critical temperature violations can be monitored via the read power required to turn on the tag transponder chip which differs in each state

Inclusive Decay Rate for B→Xd+γB \to X_d + \gamma in Next-to-Leading Logarithmic Order and CP Asymmetry in the Standard Model

We compute the decay rate for the CKM-suppressed electromagnetic penguin decay $B \to X_d + \gamma$ (and its charge conjugate) in NLO QCD, including leading power corrections in $1/m_b^2$ and $1/m_c^2$ in the standard model. The average branching ratio of the decay $B \to X_d\gamma$ and its charge conjugate is estimated to be in the range $6.0 \times 10^{-6} \leq \leq 2.6 \times 10^{-5}$, obtained by varying the CKM-Wolfenstein parameters $\rho$ and $\eta$ in the range $-0.1 \leq \rho \leq 0.4$ and $0.2 \leq \eta \leq 0.46$ and taking into account other parametric dependence. In the stated range of the CKM parameters, we find the ratio $R(d\gamma/s\gamma) = <BR(B \to X_d\gamma)>/$ to lie in the range between 0.017 and 0.074. Theoretical uncertainties in this ratio are found to be small. Hence, this ratio is well suited to provide independent constraints on the CKM parameters. The CP-asymmetry in the $B \to X_d \gamma$ decay rates is found to be in the range $(7 - 35)$. Both the decay rates and CP asymmetry are measurable in forthcoming experiments at $B$ factories and possibly at HERA-B.Comment: 17 pages including 7 postscript figures; uses epsfig; The changes w.r.t the previous version are: A comment about the Bremsstrahlung corrections is added as well as a note on the feasibility of the measurement $B -> X_d gamma

The End of Moderate Inflation in Three Transition Economies?

This paper examines the moderation of inflation in three transition economies, the Czech Republic, Hungary and Poland at the end of the 1990s. We argue that the institutions for the conduct of monetary policy in these countries were relatively weak and that monetary policy was unsupported by fiscal policy and hampered by multiple objectives. Using a VAR model of inflation, we show that, under a variety of assumptions, foreign prices and the persistence of inflation were the key determinants of inflation in these countries. From this finding we conclude that the moderation of inflation in the Czech Republic, Hungary and Poland was due largely to the decline in import prices from 1997 on, and thus it is likely be a temporary phenomenon.http://deepblue.lib.umich.edu/bitstream/2027.42/39817/3/wp433.pd