On the determination of quark masses from the Dalitz plot for the decay η → π+π?π0

An experimental Dalitz plot distribution for the decay η → π ⁺ π ⁻ π ⁰ is fitted by the theoretical one obtained in chiral perturbation theory with unitarity corrections taken into account. The fit shows that the difference of light-quark masses is larger than is expected from electromagnetic mass differences of neutral and charged kaons. From Yadernaya Fizika, Vol. 67, No. 2, 2004, pp. 443–445. Original English Text Copyright ? 2004 by Martemyanov, Sopov. This article was submitted by the authors in English.     

Calorimetry in the science of building materials

A new conceptual approach is proposed for evaluation of the most important properties of cement-containing composites on the basis of the rate and degree off completeness of hardening processes and study of the porous structure during material formation, within the limits of the system “composition-structure-process-property”.     

Synthesis and Characterization of the New Cluster Complex {Mo3S4} with the Hemilabile Phosphine-Selenoether Ligand

Russian Journal of Coordination Chemistry - The reaction of [Mo3S4(Tu)8(H2O)]Cl4·4H2O (Tu is thiourea) with (PhCH2CH2)2-PCH2CH2SeC5H11) (PSe) followed by purification on a chromatographic...     

Single- and double-pion production in nucleon collisions on the nucleon and on nuclei—the ABC effect and its origin in a dibaryonic resonance

The ABC effect-an intriguing low-mass enhancement in the ππ invariant mass spectrum-is known from inclusive measurements of two-pion production in nuclear fusion reactions. First exclusive measurements carried out at CELSIUS-WASA for the fusion reactions leading to d or ³He reveal this effect to be a σ-channel phenomenon associated with the formation of a ΔΔ system in the intermediate state and combined with a resonance-like behavior in the total cross-section. Together with the observation that the differential distributions do not change in shape over the resonance region the features fulfill the criteria of an isoscalar s-channel resonance in pn and NNππ systems, if the two emitted nucleons are bound. It obviously is robust enough to survive in nuclei as a dibaryonic resonance configuration. In this context also the phenomenon of NΔ resonances is reexamined.     

Calorimetric Study of Frost Attack During Cement Hardening

This report deals with practical and experimental studies of the effects of frost attack on hardening cement stone and concrete. The basic component of concrete, cement stone, is a typical capillary-porous material formed from solid, liquid and gaseous phases. The level of knowledge on the effects of frost attack on cement stone and concrete hardening is insufficient, due to the complexity of the mechanisms of the accompanying effects. The values of internal pressures are determined among others by ice formation parameters, by the characteristics of the porous structure and the solid phase of the cement stone, and also by technological factors. The quantitative estimation of certain parameters is important for an approach to the understanding of the mechanism of frost attack and the choice of methods of its regulation for technological purposes. These are the temperature of pore liquid crystallization T _f, the degree of freezing F _d and the mass of ice I _m formed during freezing. Examples of changes in ice formation parameters on variation of some of the technological factors are given. This revised version was published online in August 2006 with corrections to the Cover Date.     

Excitation of the Roper resonance in single- and double-pion production in nucleon-nucleon collisions⋆

In most investigations the Roper resonance is sensed only very indirectly via complex partial-wave analyses. We find indications for its excitation in the invariant nπ⁺ mass spectrum of the pp → npπ⁺ reaction at M ≈ 1360 MeV with a width of ≈ 150 MeV . The values fit very favorably to the most recent phase shift results as well as to the observations at BES. In the near-threshold two-pion production pp → ppπ⁰π⁰ , where the Roper excitation and its subsequent decays via the routes N ^* → Δπ → Nππ and N ^* → Nσ are the only dominant processes, we find its direct decay into the Nσ channel to be the by far dominating decay process --in favor of a monopole excitation of the Roper resonance.     

Elastic backward scattering of negative pions on protons at 25 and 38 GeV/c

The backward elastic scattering reaction π^?p → pπ^? at momenta 25 and 38 GeV/c have been measured using a magnetic spectrometer with hybrid chambers. The experimental data on the dependence of the cross section dσ/du on the momentum transfer u as well as the energy dependence dσ/du at u = 0 are given.     

Studies of Capillary Porosity of Clinker Phases During Hydration

The capillary porosity of clinker phases, i.e. 3CaOSiO₂, β2CaOSiO₂, 3CaOAl₂O₃ and 4CaOAl₂O₃Fe₂O₃, at the early stages of hydration has been studied by the methods of Differential Scanning Calorimetry and nitrogen adsorption (BET). It was established that pores of 3–70 nm were formed during the hydration of 3CaOSiO₂ and the maximum of their distribution was found at about 10 nm. The hydration of 2CaOSiO₂ is much slower and the porosity is one order of magnitude lower. During the hydration of 3CaOAl₂O₃ the content of crystalline hexagonal hydrates prevailed and the porosity was in the range 5–90 nm with the average pore diameter of about 16 nm. This average pore diameter was much smaller for thermoporosimetry and lay at about 7 nm. The hydrated 4CaOAl₂O₃Fe₂O₃ sample had the porosity in the range 3–90 nm with the maximum of the pores distribution at about 4 nm. There are some differences between the porosities measured by BET and thermoporosimetry. Principally thermoporosimetry gives no information about larger capillary pores in the range 30–50 nm. This revised version was published online in July 2006 with corrections to the Cover Date.