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[en] The measurement of weak neutral current processes allows a determination of the space-time structure and the isospin structure of these currents. The inclusive production data and the elastic neutrino electron scattering rules out a pure V or A structure of the current. A pure isoscalar current is in disagreement with the experimental data for the one pion production off neutrinos. Further aspects of the neutral current can be determined in neutrino-nucleus-scattering experiments. (BJ)
[de]Die Messung von schwachen neutralen Stromreaktionen erlaubt eine Bestimmung der Raum-Zeit- und der Isospinstruktur des Stromes. Die Daten der inklusiven Streuung und die elastischen Elektron-Neutrino-Ereignisse schliessen eine reine V oder A-Struktur des Stromes aus. Ein reiner Isoskalarer Strom stimmt nicht ueberein mit den experimentellen Tatsachen der 1-Pion-Produktion durch Neutrinos. In Neutrino-Kern-Streuexperimenten koennen weitere Aspekte des neutralen Stromes gemessen werden. (BJ)
[en] This paper describes the analysis used to determine the neutral current π0 production in MiniBooNE in bins of momentum. Additionally, a measurement of the relative coherent production of π0s is discussed. The coherent production rate is found to be (19.5 ±1.1 (stat) ±2.5 (sys))% of the total exclusive neutral current π0 production rate
[en] We studied non-standard neutrino interactions that can be generated by physics beyond the Standard Model. Here we focused on the flavor-changing-neutral-current which would allow neutrino flavors to change through the neutral current interaction, and the lepton non-universality that gives the difference of the neutral-currentinteraction-amplitudes among the different flavored neutrinos. In this analysis we employed the atmospheric neutrino events collected in the Super-Kamiokande I (1996-2001) and II (2003-2005) periods. We obtained the limit on the non-standard coupling parameter |εμτ|<1.1x10-2 at 90%C.L. for the flavor-changing-neutralcurrent. This limit resulted in being consistent with the expectation of the Standard Model.
[en] The Main Injector Neutrino Oscillation Search (MINOS) long-baseline experiment has been actively collecting beam data since 2005, having already accumulated 3 x 1020 protons-on-target (POT). The several million neutrinos per year observed at the Near detector may improve the existing body of knowledge of neutrino cross-sections and the Near-Far comparison of the observed energy spectrum neutral current events constrains oscillations into sterile neutrinos. MINOS capabilities of observing neutral current neutrino events are described and the employed methodology for event selection is discussed, along with preliminary results obtained. An outlook on the expected neutral current related contributions from MINOS is also presented
[en] Employing the analytic expression (to the next leading order) of the nonsinglet component of the structure function which we obtain from QCD theory, and using the recent experimental results of the neutral-current structure function at Q2 = 11(GeV/c)2 as input, we derive the QCD predictions for the scaling violation behavior of the neutral-current structure function
[en] The utility of the bremsstrahlung process in detecting parity violations from V-A weak neutral current interference is analysed in two ways. Firstly, bremsstrahlung from polarized lepton-nucleus scattering has an asymmetry with respect to the polarization of the incident leptons, and secondly, bremsstrahlung from unpolarized lepton nucleus scattering has a small circular polarization. The magnitude of each effect is calculated. The ratio of the parity violating contribution and the parity conserving contribution to the cross section is shown to be a misleading measure of the utility of these experiments. A parameter, the figure of merit, is introduced and used to discuss the feasibility of possible experiments
[en] In this paper we study nonstandard neutrino interactions as an example of physics beyond the standard model using atmospheric neutrino data collected during the Super-Kamiokande I (1996-2001) and II (2003-2005) periods. We focus on flavor-changing-neutral-currents (FCNC), which allow neutrino flavor transitions via neutral current interactions, and effects which violate lepton nonuniversality and give rise to different neutral-current interaction-amplitudes for different neutrino flavors. We obtain a limit on the FCNC coupling parameter, εμτ, |εμτ|<1.1x10-2 at 90% C.L. and various constraints on other FCNC parameters as a function of the nonuniversality coupling, εee. We find no evidence of nonstandard neutrino interactions in the Super-Kamiokande atmospheric data.