Extracting weak phase information from B-->V1V2 decays

We describe a new method for extracting weak, CP-violating &Dmacr;phase information, with no hadronic uncertainties, from an angular analysis of B-->V1V2 decays, where V1 and V2 are vector mesons. The quantity sin (2)(2beta+gamma) can be cleanly obtained from the study of decays such as B(0)(d)(t)-->D*+/-rho(-/+), D(*+/-)a(-/+)(1), D(;) *0K(;) (*0), etc. Similarly, one can use B(0)(s)(t)-->D(*+/-)(s)K*-/+ to extract sin (2)gamma. There are no penguin contributions to these decays. It is possible that sin (2)(2beta+gamma) will be the second function of CP phases, after sin2beta, to be measured at B factories.     

Monotonicity of permanents of certain doubly stochastic circulant matrices

Let p_k(A), k=2,…,n, denote the sum of the permanents of all k×k submatrices of the n×n matrix A. A conjecture of Ðokovi?, which is stronger than the famed van der Waerden permanent conjecture, asserts that the functions p_k((1?θ)J_n+;θA), k=2,…, n, are strictly increasing in the interval 0?θ?1 for every doubly stochastic matrix A. Here J_n is the n×n matrix all whose entries are equal $\text{1}\text{n}$. In the present paper it is proved that the conjecture holds true for the circulant matrices A=αI_n+ βP_n, α, β?0, α+;β=1, and $\text{A=}\text{(nJ}{}_{\mathrm{n}}\text{?I}{}_{\mathrm{n}}\text{?P}{}_{\mathrm{n}}\text{)}\text{(n?2)}$, where I_n and P_n are respectively the n×n identify matrix and the n×n permutation matrix with 1's in positions (1,2), (2,3),…, (n?1, n), (n, 1).     

Dynamic Frequency Shifts of Complexed Ligands: An NMR Study ofd-[1-C,1-H]Glucose Complexed to theEscherichia coliPeriplasmic Glucose/Galactose Receptor

The¹³C multiplet structure ofd-[1-¹³C,1-²H]glucose complexed to theEscherichia coliperiplasmic glucose/galactose receptor has been studied as a function of temperature. Asymmetric multiplet patterns observed are shown to arise from dynamic frequency shifts. Multiplet asymmetry contributions resulting from shift anisotropy–dipolar cross correlations were found to be small, with optimal fits of the data corresponding to small, negative values of the correlation factor, χ^CD-CSA. Additional broadening at higher temperatures most probably results from ligand exchange between free and complexed states. Effects of internal motion are also considered theoretically, and indicate that the order parameter for the bound glucose is ≥0.9.     

Encapsulation and diffraction-pattern-correction methods to reduce the effect of damage in x-ray diffraction imaging of single biological molecules

Short and intense x-ray pulses may be used for atomic-resolution diffraction imaging of single biological molecules. Radiation damage and a low signal-to-noise ratio impose stringent pulse requirements. In this Letter, we describe methods for decreasing the damage and improving the signal by encapsulating the molecule in a sacrificial layer (tamper) that reduces atomic motion and by postprocessing the pulse-averaged diffraction pattern to correct for ionization damage. Simulations show that these methods greatly improve the image quality.     

Chemical Modification of Glycosaminoglycan Polysaccharides

The linear anionic class of polysaccharides, glycosaminoglycans (GAGs), are critical throughout the animal kingdom for developmental processes and the maintenance of healthy tissues. They are also of interest as a means of influencing biochemical processes. One member of the GAG family, heparin, is exploited globally as a major anticoagulant pharmaceutical and there is a growing interest in the potential of other GAGs for diverse applications ranging from skin care to the treatment of neurodegenerative conditions, and from the treatment and prevention of microbial infection to biotechnology. To realize the potential of GAGs, however, it is necessary to develop effective tools that are able to exploit the chemical manipulations to which GAGs are susceptible. Here, the current knowledge concerning the chemical modification of GAGs, one of the principal approaches for the study of the structure-function relationships in these molecules, is reviewed. Some additional methods that were applied successfully to the analysis and/or processing of other carbohydrates, but which could be suitable in GAG chemistry, are also discussed.     

Self-similar modes of coherent diffusion

Self-similar solutions of the coherent diffusion equation are derived and measured. The set of real similarity solutions is generalized by the introduction of a nonuniform phase, based on the elegant Gaussian modes of optical diffraction. In a light-storage experiment, the complex solutions are imprinted on a gas of diffusing atoms, and the self-similar evolution of both their amplitude and phase pattern is demonstrated. An algebraic decay depending on the mode order is measured. Notably, as opposed to the regular diffusion spreading, a subset of the solutions exhibits a self-similar contraction.     

Final-state polarization in <Emphasis Type="Italic">B</Emphasis><Stack><Subscript><Emphasis Type="Italic">s</Emphasis></Subscript><Superscript>0</Superscript></Stack> decays

Certain B _s ⁰→V ₁ V ₂ decays (V _i is a vector meson) can be related by flavor SU(3) symmetry to corresponding B _d ⁰→V ₃ V ₄ decays. In this paper, we show that the final-state polarization can be predicted in the B _s ⁰ decay, assuming polarization measurements of the B _d ⁰ decay. This can be done within the scenario of penguin annihilation (PA), which has been suggested as an explanation of the unexpectedly large transverse polarization in B→φ K ^*. PA is used to estimate the breaking of flavor SU(3) symmetry in pairs of decays. Two of these for which PA makes a reasonably precise prediction of the size of SU(3) breaking are (B _s ⁰→φ φ,B _d ⁰→φ K ^0*) and ( ). The polarization measurement in the B _d ⁰ decay can be used to predict the transverse polarization in the B _s ⁰ decay and will allow for testing of PA as well as the other assumptions in the analysis.