Method for taking into account hard-photon emission in four-fermion processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aleksejevs, A. G., E-mail: aaleksejevs@swgc.mun.ca; Barkanova, S. G., E-mail: svetlana.barkanova@acadiau.ca; Zykunov, V. A., E-mail: vladimir.zykunov@cern.ch

2016-01-15

A method for taking into account hard-photon emission in four-fermion processes proceeding in the s channel is described. The application of this method is exemplified by numerically estimating one-loop electroweak corrections to observables (cross sections and asymmetries) of the reaction e{sup −}e{sup +} → μ{sup −}μ{sup +}(γ) involving longitudinally polarized electrons and proceeding at energies below the Z-resonance energy.

Detection prospects of the cosmic neutrino background

NASA Astrophysics Data System (ADS)

Li, Yu-Feng

2015-04-01

The existence of the cosmic neutrino background (CνB) is a fundamental prediction of the standard Big Bang cosmology. Although current cosmological probes provide indirect observational evidence, the direct detection of the CνB in a laboratory experiment is a great challenge to the present experimental techniques. We discuss the future prospects for the direct detection of the CνB, with the emphasis on the method of captures on beta-decaying nuclei and the PTOLEMY project. Other possibilities using the electron-capture (EC) decaying nuclei, the annihilation of extremely high-energy cosmic neutrinos (EHECνs) at the Z-resonance, and the atomic de-excitation method are also discussed in this review (talk given at the International Conference on Massive Neutrinos, Singapore, 9-13 February 2015).

On the structure and radiation chemistry of iron phosphate glasses: New insights from electron spin resonance, Mössbauer, and evolved-gas mass spectroscopy

NASA Astrophysics Data System (ADS)

Griscom, D. L.; Merzbacher, C. I.; Bibler, N. E.; Imagawa, H.; Uchiyama, S.; Namiki, A.; Marasinghe, G. K.; Mesko, M.; Karabulut, M.

1998-05-01

Several vitreous forms for immobilization of plutonium and/or high-level nuclear wastes have been surveyed by electron spin resonance (ESR) to gain insights into their atomic-scale structures and to look for signs of radiolytic decomposition resulting from exposures to γ-ray doses of 30 MGy. While preliminary results are reported for Defense Waste Processing Facility (DWPF) borosilicate compositions and an experimental lanthanum-silicate glass, this paper focusses primarily on a class of glasses containing 40-75 mol% P 2O 5 and up to 40 mol% Fe 2O 3. Each of the six diverse compositions investigated displayed characteristic ESR signals (not resembling those of the iron-containing phosphorus-free glasses) comprising combinations of an extremely broad "X resonance" and a narrow "Z resonance", both centered near g=2.00 and both displaying nearly perfect Lorentzian line shapes (peak-to-peak derivative widths ˜300-600 mT and ˜30 mT, respectively, at 300 K). The X-resonance intensities in the air-melted glasses correlated linearly with Fe:P ratio up to [Fe 2O 3]/[P 2O 5] ≈ 0.6, where intensity values ˜1 spin/phosphorus were reached. Mössbauer studies showed that the [Fe 3+]/[Fe] tot ratio could be varied from 0.82 to 0.49 by raising the melting temperature in air from 1150°C to 1450°C and/or by employing mildly reducing atmospheres. The combined X + Z-resonance intensities were reduced to zero for [Fe 3+]/[Fe] tot less than ˜0.6, leaving only a much weaker spectrum attributable to Fe 3+ ions. The X and Z ESR signals of the iron phosphate glasses resemble nothing else in the literature except the correspondingly denoted signals in an iron-free amorphous peroxyborate (APB) preparation. The X and Z resonances in the latter are deemed to arise from superoxide ions (O 2-) in the borate network and in a separated Na 2O 2 phase, respectively. An asymmetric Z resonance signal attributable to interstitial O 2- species was a radiation-induced manifestation in phosphate