Evidence for CP violation in time-integrated D0→h(-)h(+) decay rates

A search for time-integrated CP violation in D(0)→h(-)h(+) (h=K, π) decays is presented using 0.62 fb(-1) of data collected by LHCb in 2011. The flavor of the charm meson is determined by the charge of the slow pion in the D(*+)→D(0)π(+) and D(*-)→D[over ˉ](0)π(-) decay chains. The difference in CP asymmetry between D(0)→K(-)K(+) and D(0)→π(-)π(+), ΔA(CP)≡A(CP)(K(-)K(+))-A(CP)(π(-)π(+)), is measured to be [-0.82±0.21(stat)±0.11(syst)]%. This differs from the hypothesis of CP conservation by 3.5 standard deviations.     

Integrated and compact fiber-coupled single-photon system based on nitrogen-vacancy centers and gradient-index lenses

A fiber-coupled single-photon system is presented. Gradient-index lenses are utilized for single-photon collection and fiber coupling of a nitrogen-vacancy defect center in a nanodiamond. Integrated filter technology separates excitation and laser light. Therefore, the system is ultracompact with 120 mm(3) in dimension as no bulky free beam optics are used. The commercial availability of all components and their simple assembly allows the implementation of a low-cost single-photon system, possibly approaching single-photon count rates of 500 kcts/s.     

WGM microresonators: sensing,lasing and fundamental optics with microspheres

Glass microsphere resonators that support optical resonances known as whispering‐gallery modes are unique tools for studying and exploiting optical effects under extremely well controlled conditions. In this paper, a review focusing mostly on glass microsphere resonators is presented. First, a brief historical background is given in which we see how the state‐of‐the‐art has grown from novel optical resonators to the ultrahigh Q cavities used in cutting‐edge experiments. After the basic properties of microsphere resonators are outlined we will discuss some of the recent experiments involving microsphere resonators, although some discussion involving polymeric microspheres is also included. The use of doped and undoped microspheres in optical signal processing, optical sensing and quantum optics is highlighted. Finally, there is a brief review of recent optomechanical experiments that use microspheres.     

Isochoric measurement of the equation of state of solid argon at high pressure

Isochoric P-T traces have been measured for solid argon at eight different molar volumes by using a capacitance technique which records the radial expansion of the vessel due to pressure. These measurements extend from melting curve temperatures down to 4 °K at pressures ranging up to 7 kbar.Analysis of the data indicates that, for the high temperature region (above 80 °K) the thermodynamic derivative ?P/?T_r is independent of both temperature and density to within experimental errors. Using the fact that ?P/?T_r is constant, it is possible to generate PVT and isothermal bulk modulus data at high temperatures. These data are compared with X-ray diffraction measurements and piston displacement data and are found to be in good agreement with both. The data also agree quite well with current theoretical predictions. The high-temperature bulk modulus data were found to have a simple exponential dependence on the molar volume, prividing another convenient representation of the high-temperature equation-of-state data.     

The image of the transfer map

Archiv der Mathematik -     

Kinetics of the iodine atom catalyzed gas phase geometrical isomerization of diiodoethylene. Rotation about a single bond

The spectrophotometric determination of the rate of iodine atom catalyzed geometrical isomerization of diiodoethylene in the gas phase from 502.8 to 609.1°K leads to a rate constant for the bimolecular reaction between I and trans-diiodoethylene of log k_t?c(M^?1 sec^?1) = 8.85 ± 0.12 ? (11.01 ± 0.30)/θ. Estimates of the entropy and enthalpy change for the addition of I atoms to trans-diiodoethylene (process a.b) lead to log K_a.b(M^?1) = ?2.99 ? 4.0/θ, and thus to log k_c (sec^?1) = log k_t?c – log K_ab = 11.8 ?7.0/θ for the rate constant for rotation about the single bond in the adduct radical. The theory for calculation of the rotation rate constant is presented and it is shown that while the exact value depends on the barrier height, a value of 6.8 kcal/mole for this quantity leads to log k (sec^?1) = 11.8 ?6.7/θ. The activation energy points to a better value of the group contribution to heat of formation of the group C -(I)₂(H)(C) than one based on bond additivity.     

The kinetics of the interaction of peroxy radicals. II. Primary and secondary alkyl peroxy

A chain mechanism is proposed to account for the very rapid termination reactions observed between alkyl peroxy radicals containing α-C—H bonds which are from 10⁴ to 10⁶ faster than the termination of tertiary alkyl peroxy radicals. The new mechanism is with termination by . \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm R}\overline {{\rm CHOO}} $\end{document} is the zwitterion originally postulated by Criegee to account for the chemistry of O₃-olefin addition. Heats of formation are estimated for \documentclass{article}\pagestyle{empty}\begin{document}$ \overline {{\rm CH}_2 {\rm OO,}} {\rm }\overline {{\rm RCHOO}} $\end{document}, and \documentclass{article}\pagestyle{empty}\begin{document}$ ({\rm C}\overline {{\rm H}_3 )_2 {\rm COO}} $\end{document} and it is shown that all steps in the mechanism are exothermic. The second step can account for (¹Δ)O₂ which has been observed. k₁ is estimated to be 10^9–2/θ liter/M sec where θ = 2.303RT in kcal/mole. The second and third steps constitute a chain termination process where chain length is estimated at from 2 to 10. This mechanism for the first time accounts for minor products such as acid and ROOH found in termination reactions. Trioxide (step 3) is shown to be important below 30°C or in very short time observations (<10 s at 30°C). Solvent effects are also shown to be compatible with the new mechanism.     

Self-consistent selection of a superconducting representation for the BCS model

Taking the BCS Hamiltonian written in second-quantized form, a modified form of Umezawa's self-consistent field theory method is applied, and a unitarily nonequivalent representation is selected in which the Hamiltonian obviously describes a superconducting system. This result is not at all obvious, since the original Hamiltonian is completely symmetric, and there is no reason a priori for expecting it to describe an asymmetric superconducting configuration. All higher order terms are accounted for, and in doing so, one finds the existence of the energy-gap condition for Cooper pairs. The representation is picked out without using the adiabatic theorem or pair approximation, as is typically done in the self-consistent method for superconductivity.