No Arabic abstract
More than forty years after the first detection of neutrinos from the Sun, the spectroscopy of solar neutrinos has proven to be an on-going success story. The long-standing puzzle about the observed solar neutrino deficit has been resolved by the discovery of neutrino flavor oscillations. Todays experiments have been able to solidify the standard MSW-LMA oscillation scenario by performing precise measurements over the whole energy range of the solar neutrino spectrum. This article reviews the enabling experimental technologies: On the one hand mutli-kiloton-scale water Cherenkov detectors performing measurements in the high-energy regime of the spectrum, on the other end ultrapure liquid-scintillator detectors that allow for a low-threshold analysis. The current experimental results on the fluxes, spectra and time variation of the different components of the solar neutrino spectrum will be presented, setting them in the context of both neutrino oscillation physics and the hydrogen fusion processes embedded in the Standard Solar Model. Finally, the physics potential of state-of-the-art detectors and a next-generation of experiments based on novel techniques will be assessed in the context of the most interesting open questions in solar neutrino physics: a precise measurement of the vacuum-matter transition curve of electron-neutrino oscillation probability that offers a definitive test of the basic MSW-LMA scenario or the appearance of new physics; and a first detection of neutrinos from the CNO cycle that will provide new information on solar metallicity and stellar physics.
The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program (WINP) at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summarizes discussion and conclusions from the workshop.
OPERA is a long-baseline experiment at the Gran Sasso laboratory (LNGS) designed to search for $ u_mu rightarrow u_tau$ oscillations in appearance mode. OPERA took data from 2008 to 2012 with the CNGS neutrino beam from CERN. The data analysis is ongoing, with the goal of establishing $ u_tau$ appearance with high significance and improving the sensitivity to the sterile neutrino search in the $ u_mu$ $rightarrow$ $ u_e$ appearance channel. Current results will be presented and perspectives discussed.
Tests on $B-L$ symmetry breaking models are important probes to search for new physics. One proposed model with $Delta(B-L)=2$ involves the oscillations of a neutron to an antineutron. In this paper a new limit on this process is derived for the data acquired from all three operational phases of the Sudbury Neutrino Observatory experiment. The search was concentrated in oscillations occurring within the deuteron, and 23 events are observed against a background expectation of 30.5 events. These translate to a lower limit on the nuclear lifetime of $1.48times 10^{31}$ years at 90% confidence level (CL) when no restriction is placed on the signal likelihood space (unbounded). Alternatively, a lower limit on the nuclear lifetime was found to be $1.18times 10^{31}$ years at 90% CL when the signal was forced into a positive likelihood space (bounded). Values for the free oscillation time derived from various models are also provided in this article. This is the first search for neutron-antineutron oscillation with the deuteron as a target.
The energy spectrum of a neutrino beam in the few-GeV region is free of uncertainties from nuclear effects when reconstructed via neutrino-hydrogen interactions. On a multinuclear (hydrogen containing) target such interactions can be extracted using transverse kinematic imbalance. We discuss the prospects of this technique for current experiments.
Results are presented for a simulation carried out to test the precision with which a detector design (HERON) based on a superfluid helium target material should be able to measure the solar pp and Be7 fluxes. It is found that precisions of +/- 1.68% and +/- 2.97% for pp and Be7 fluxes, respectively, should be achievable in a 5-year data sample. The physics motivation to aim for these precisions is outlined as are the detector design, the methods used in the simulation and sensitivity to solar orbit eccentricity.