Measurement of the single-spin asymmetry in the reaction π − d ↑ → π 0 X in the beam-fragmentation region at 40 GeV and p T of up to 2 GeV/c

The single-spin asymmetry A _N in the reaction π ^? + d _↑ → π ⁰ + X in the beam-fragmentation region at the energy of 40 GeV was investigated by using the PROZA setup installed at the U-70 accelerator of the Institute for High Energy Physics (IHEP, Protvino). It was measured to be A _N = (13.6 ± 2.6(stat.) ± 2.0(syst.))% in the intervals 0.7 < x _F < 1.0 and 1.0 < p _T < 1.8 GeV/c. The results agree with the asymmetry of π ⁰ mesons in the charge-exchange reaction π ^? + p _↑ → π ⁰ + n at the same values of the transverse momentum and beam energy. The asymmetry in the reaction K ^? + d _↑ → π ⁰ + X was simultaneously measured and found to be A _N = (11 ± 14)% for p _T > 1.2 GeV/c.     

Search for R-parity violating decays of sneutrinos to eμ, μτ, and eτ pairs in pp collisions at square root s = 1.96 TeV

We present a search for supersymmetric neutrino ν production using the Tevatron pp collision data collected with the CDF II detector and corresponding to an integrated luminosity of 1 fb-1. We focus on the scenarios predicted by the R-parity violating (RPV) supersymmetric models in which sneutrinos decay to two charged leptons of different flavor. With the data consistent with the standard model expectations, we set upper limits on σ(pp→ν)×BR(ν→eμ,μτ,eτ) and use these results to constrain the RPV couplings as a function of the sneutrino mass.     

Polarization observablesΣ,P y,T 1 in the reaction\vec \gamma d \to \vec pn at photon energies between 200 and 600 MeV and dibaryon resonances

The polarization observables Σ,P _y ,T ₁,P _y ^⊥ ,P _y ^∥ are derived in proton polarization measurements of the \(\vec \gamma d \to \vec pn\) reaction, using a linearly polarized photon beam of energies between 300 and 600 MeV for c.m.s. proton emission angles of 90° and 120°. A multipole analysis is performed in the framework of the gauge-invariant pole model considering theγN→πN amplitudes and the deuteron structure without dibaryon resonances and with different sets of isovector and isoscalar dibaryon resonances. It is shown that the inclusion of dibaryon resonances substantially improves agreement with experimental data.     

Spreadsheets to calculate P–V–T relations,thermodynamic and thermoelastic properties of silicates in the MgSiO3–MgO system

Modified equations of state (EoS) of forsterite, wadsleyite, ringwoodite, akimotoite, bridgmanite and post-perovskite based on the Helmholtz free energy are described using Microsoft Excel spreadsheets. The equations of state were set up by joint analysis of reference experimental data and can be used to calculate thermodynamic and thermoelastic parameters and P–V–T properties of the Mg-silicates. We used Visual Basic for Applications module in Microsoft Excel and presented a simultaneous calculation of full set of thermodynamic and thermoelastic functions using only T–P and T–V data as input parameters. Phase transitions in the MgSiO₃–MgO system play an important role in the interpretation of the seismic boundaries of the upper Earth’s mantle and in the D″ layer. Therefore, proposed EoSes of silicates in the MgSiO₃–MgO system have clear geophysical implications. The developed software will be interesting to specialists who are engaged to study the mantle mineralogy and Earth’s interior.     

Optically detected EPR effect in the ã3 Au triplet state of the oxalylfluoride molecule excited to the 413, 423 and 431 rotational levels of the 00(Ã1 Au ) vibronic state

In the present study, resolved OD EPR spectra were measured for the 4₃₁, 4₂₃, and 4₁₃ levels of the ù A_u 0⁰ vibronic state. Values of the fine and hyperfine constants were estimated from an analysis of these spectra for the triplet rotational levels, coupled by the intramolecular interactions with the singlet levels studied. It was shown that the microwave power dependence differs significantly for different lines of the OD EPR spectrum. This difference can be explained by a model where the microwave field saturation effect is observed for different OD EPR lines at different power values of the microwave field. The decay profile can be fitted by a biexponential function in the presence of both magnetic and microwave fields. The observed data were analysed using the electron and nuclear spin decoupling mechanism in the limit of low level density.     

The use of radon (Rn-222) and volatile organic compounds in monitoring soil gas to localize NAPL contamination at a gas station in Rio Claro,São Paulo State,Brazil

This study focuses on the presence of radon (²²²Rn) and volatile organic compounds (VOCs) in soil gases at a gas station located in the city of Rio Claro, São Paulo, Brazil, where a fossil fuel leak occurred. The spatial distribution results show a correlation between ²²²Rn and VOCs, consistent with the fact that radon gas has a greater chemical affinity with organic phases than with water. This finding demonstrates that the presence of a residual hydrocarbon phase in an aquifer can retain radon, leading to a reduced radon content in the soil gas. The data in this study confirm the results of previous investigations, in which the method used in this study provided a preliminary fingerprint of a contaminated area. Furthermore, the data analysis time is brief, and only simple equipment is required.