Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userObservation of Electron Neutrino Appearance in a Muon Neutrino Beam
120
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3$sigma$ when compared to 4.92 $pm$ 0.55 expected background events. In the PMNS mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles $theta_{12}$, $theta_{23}$, $theta_{13}$, a mass difference $Delta m^2_{32}$ and a CP violating phase $delta_{mathrm{CP}}$. In this neutrino oscillation scenario, assuming $|Delta m^2_{32}| = 2.4 times 10^{-3}$ $rm eV^2$, $sin^2 theta_{23} = 0.5$, and $Delta m^2_{32} >0$ ($Delta m^2_{32} <0$), a best-fit value of $sin^2 2 theta_{13}$ = $0.140^{+0.038}_{-0.032}$ ($0.170^{+0.045}_{-0.037}$) is obtained at $delta_{mathrm{CP}}=0$. When combining the result with the current best knowledge of oscillation parameters including the world average value of $theta_{13}$ from reactor experiments, some values of $delta_{mathrm{CP}}$ are disfavored at the 90% CL.
rate research
Read More
The T2K collaboration: reports evidence for electron neutrino appearance at the atmospheric mass splitting, |Delta m_{32}^2|=2.4x10^{-3} eV^2. An excess of electron neutrino interactions over background is observed from a muon neutrino beam with a peak energy of 0.6 GeV at the Super-Kamiokande (SK) detector 295 km from the beams origin. Signal and background predictions are constrained by data from near detectors located 280 m from the neutrino production target. We observe 11 electron neutrino candidate events at the SK detector when a background of 3.3pm0.4(syst.) events is expected. The background-only hypothesis is rejected with a p-value of 0.0009 (3.1sigma), and a fit assuming u_{mu}-> u_e oscillations with sin^2(2theta_{23})=1, delta_{CP}=0 and |Delta m_{32}^2|=2.4x10^{-3} eV^2 yields sin^2(2theta_{13})=0.088^{+0.049}_{-0.039}(stat.+syst.).
The T2K experiment observes indications of $ u_murightarrow u_e$ appearance in data accumulated with $1.43times10^{20}$ protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with $|Delta m_{23}^2|=2.4times10^{-3}$ eV$^2$, $sin^2 2theta_{23}=1$ and $sin^2 2theta_{13}=0$, the expected number of such events is 1.5$pm$0.3(syst.). Under this hypothesis, the probability to observe six or more candidate events is 7$times10^{-3}$, equivalent to 2.5$sigma$ significance. At 90% C.L., the data are consistent with 0.03(0.04)$<sin^2 2theta_{13}<$ 0.28(0.34) for $delta_{rm CP}=0$ and a normal (inverted) hierarchy.
A search for muon anti-neutrino to electron anti-neutrino oscillations was conducted by the Liquid Scintillator Neutrino Detector at the Los Alamos Neutron Science Center using muon anti-neutrinos from positive muon decay at rest. A total excess of 87.9 +/- 22.4 +/- 6.0 events consistent with electron anti-neutrino plus proton scattering to positron plus neutron was observed above the expected background. This excess corresponds to an oscillation probability of (0.264 +/- 0.067 +/- 0.045), which is consistent with an earlier analysis. In conjunction with other known limits on neutrino oscillations, the LSND data suggest that neutrino oscillations occur in the 0.2-10 eV^2/c^4 Delta-m^2 range, indicating a neutrino mass greater than 0.4 eV/c^2.
This letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rate and energy spectra of charged current muon neutrino interactions are compared in two detectors located along the beam axis at distances of 1 km and 735 km. With 1.27 x 10^{20} 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336 pm 14.4 events. The data are consistent with muon neutrino disappearance via oscillation with |Delta m^2_{23}| = 2.74^{+0.44}_{-0.26} x 10^{-3} eV^2/c^4 and sin^2(2theta_{23}) > 0.87 (at 60% C.L.).
We report results from the first search for $ u_muto u_e$ transitions by the NOvA experiment. In an exposure equivalent to $2.74times10^{20}$ protons-on-target in the upgraded NuMI beam at Fermilab, we observe 6 events in the Far Detector, compared to a background expectation of $0.99pm0.11$ (syst.) events based on the Near Detector measurement. A secondary analysis observes 11 events with a background of $1.07pm0.14$ (syst.). The $3.3sigma$ excess of events observed in the primary analysis disfavors $0.1pi < delta_{CP} < 0.5pi$ in the inverted mass hierarchy at the 90% C.L.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
