Analyzing power in elastic scattering of the electrons off a spin-0 target

We consider the analyzing power on a spin-0 nuclear target. This observable is related to the imaginary part of the two-photon-exchange (box) diagram. We consider the contributions of elastic and inelastic intermediate states. The former requires knowledge of the elastic nuclear form factor, while the latter uses the optical theorem as input. The elastic contribution scales as the nuclear charge $Z$, while the inelastic contribution as the ratio of the atomic number and nuclear charge, $A/Z$. We provide estimates for $^4$He and $^{208}$Pb, in the kinematics of existing or upcoming experiments. In both cases, we predict negative values of a few parts per million, and the dominant contribution is due to inelastic contributions. The analyzing power can contribute a substantial systematic error in parity-violating experiments.Comment: 6 pages, 8 figure, one table; submitted to Phys.Rev.C; one figure corrrecte

Model-dependence of the γZ\gamma Z dispersion correction to the parity-violating asymmetry in elastic epep scattering

We analyze the dispersion correction to elastic parity violating electron-proton scattering due to $\gamma Z$ exchange. In particular, we explore the theoretical uncertainties associated with modeling contributions of hadronic intermediate states. Taking into account constraints from low- and high-energy, parity-conserving electroproduction measurements, choosing different models for contributions from the non-resonant processes, and performing the corresponding flavor rotations to obtain the electroweak amplitude, we arrive at an estimate of the uncertainty in the total contribution to the parity-violating asymmetry. At the kinematics of the Q-Weak experiment, we obtain a correction to the asymmetry equivalent to a shift in the proton weak charge of $(0.0054\pm0.0020)$. This should be compared to the value of the proton's weak charge of \qwp=0.0713\pm0.0008 that includes SM contributions at tree level and one-loop radiative corrections. Therefore, we obtain a new Standard Model prediction for the parity-violating asymmetry in the kinematics of the Q-Weak experiment of $(0.0767\pm0.0008\pm0.0020_{\gamma Z})$. The latter error leads to a relative uncertainty of 2.8% in the determination of the proton's weak charge, and is dominated by the uncertainty in the isospin structure of the inclusive cross section. We argue that future parity-violating inelastic $ep$ asymmetry measurements at low-to-moderate $Q^2$ and $W^2$ could be exploited to reduce the uncertainty associated with the dispersion correction. Because the corresponding shift and error bar decrease monotonically with decreasing beam energy, a determination of the proton's weak charge with a lower-energy experiment or measurements of "isotope ratios" in atomic parity-violation could provide a useful cross check on any implications for physics beyond the Standard Model derived from the Q-Weak measurement.Comment: 25 pages, 17 figures, 4 tables; revised version accepted for publication in PR

Dispersion of watermelon rinds as secondary raw materials in technologies of pectin-containing extracts and film structures

The development of protective coatings based on pectin substances that serve as natural structure-forming agents developed from a secondary resource base is focused on removing a complex problem in the production of finished products by deep processing of basic raw materials and developing an original film material. At the same time, the technical result of obtaining pectin-containing film structures is their ability to protect food products from microbiological spoilage, natural losses during storage and the preservation of quality and safety indicators. An important preparatory procedure that determines the efficiency and intensity of extraction processes can be attributed to the operation of dispersing the feedstock, since it directly affects the size of the contact surface area of the phases involved in mass transfer. However, it is clear that the greater the degree of grinding, the higher the efficiency of the process, but an excessive increase can lead to additional unjustified energy costs and, as a result, to an increase in the cost of the finished products sold. In this regard, the purpose of the research is to analyze existing technologies for producing pectin-containing extracts, in which watermelon rinds can be used as secondary resources and to intensify the extraction process by conducting a rational preparatory procedure for grinding the raw materials. The object of the research are watermelon rinds as non-recyclable waste from processing watermelon raw materials. According to the obtained graphs, and taking into account the high rates of gelatinization of the obtained pectin extracts, it is possible to recommend a complex treatment of watermelon rinds, including, in addition to the operations of preliminary preparation of raw materials, ultrasonic exposure and acid hydrolysis, and it is desirable to use food acids, for example, acetic or citric, instead of aggressive sulfuric and hydrochloric acids. As a result of the study of the dispersed composition, it has been concluded that the average equivalent particle size of the dispersed raw materials does not exceed the recommended limits, that is, the result obtained can be considered acceptable