The Dipion Mass Spectrum In e+e- Annihilation and tau Decay: A Dynamical (rho0, omega, phi) Mixing Approach

We readdress the problem of finding a simultaneous description of the pion form factor data in e+e- annihilations and in tau decays. For this purpose, we work in the framework of the Hidden Local Symmetry (HLS) Lagrangian and modify the vector meson mass term by including the pion and kaon loop contributions. This leads us to define the physical rho, omega and phi fields as linear combinations of their ideal partners, with coefficients being meromorphic functions of s, the square of the 4--momentum flowing into the vector meson lines. This allows us to define a dynamical, i.e. s-dependent, vector meson mixing scheme. The model is overconstrained by extending the framework in order to include the description of all meson radiative (V P gamma and P gamma gamma couplings) and leptonic (Ve+e- couplings) decays and also the isospin breaking (omega/ phi --> pi+ pi-) decay modes. The model provides a simultaneous, consistent and good description of the e+e- and tau dipion spectra. The expression for pion form factor in the latter case is derived from those in the former case by switching off the isospin breaking effects specific to e+e- and switching on those for tau decays. Besides, the model also provides a good account of all decay modes of the form V P gamma, Pgamma gamma as well as the isospin breaking decay modes. It leads us to propose new reference values for the rho^0 --> e+ e- and omega --> pi+ pi- partial widths which are part of our description of the pion form factor. Other topics (phi --> K anti K, the rho meson mass and width parameters) are briefly discussed. Therefore, we confirm the 3.3 sigma discrepancy between the theoretical estimate of a_mu based on e+e- and its direct BNL measurement.Comment: 71 pages, 8 figures. Accepted by EPJ C. Version 3: correct minor typos, minor changes spread out into the text. Extension of Sections 12.2 and 12.3.5 and introduction of the new Appendix

Results from the CUORE-0 experiment

The CUORE-0 experiment searched for neutrinoless double beta decay in 130Te using an array of 52 tellurium dioxide crystals, operated as bolometers at a temperature of 10 mK. It took data in the Gran Sasso National Laboratory (Italy) since March 2013 to March 2015. We present the results of a search for neutrinoless double beta decay in 9.8 kg-years 130Te exposure that allowed us to set the most stringent limit to date on this half-life. The performance of the detector in terms of background and energy resolution is also reported

Investigation of the MILD combustion regime via Principal Component Analysis

info:eu-repo/semantics/publishe

Reaction zone weakening effects under hot and diluted oxidant stream conditions

This paper reports computational results, to complement experimental observations, on the turbulence-chemistry interaction of nonpremixed jet flames issuing into a heated and highly diluted oxidant stream. It is found experimentally that large-scale vortices and flame stretch can lead to spatial thinning and a decrease in OH concentration. This reduction in OH is described as a weakening of the reaction zone. Accompanying reaction zone weakening is also an increase in H2CO levels. The reduction in reaction rates is most noticeable at low oxidant stream O2 levels. The heated and low oxygen oxidant conditions typify those of moderate or intense low oxygen dilution (MILD) combustion. The computational results indicate that the effects of the low oxygen levels of MILD combustion leads to both a reduction in reaction rates and an increase in transport of O2 across the reaction zone. The relationship between the reaction rate and level of O2 permeation suggests that a form of partial premixing can occur under MILD combustion conditions. This partial premixing leads to the formation of flame intermediates, which contribute to the stabilization of the flames. The permeation effects are most pronounced at high strain rates, which are commonly encountered in practical MILD combustors.Paul R. Medwell, Peter A. M. Kalt, and Bassam B. Dall