The JUNO experiment locates in Jinji town, Kaiping city, Jiangmen city, Guangdong province. The geographic location is east longitude 112 • 31'05' and North latitude 22 • 07'05'. The experimental site is 43 km to the southwest of the Kaiping city, a county-level city in the prefecture-level city Jiangmen in Guangdong province. There are five big cities, Guangzhou, Hong Kong, Macau, Shenzhen, and Zhuhai, all in ∼200 km drive distance, as shown in figure 3.
and comprise 7.482 × 10 20 protons on target in neutrino mode, which yielded in the far detector 32 e-like and 135 μ-like events, and 7.471 × 10 20 protons on target in antineutrino mode, which yielded 4 e-like and 66 μ-like events. Reactor measurements of sin 2 2θ 13 have been used as an additional constraint. The one-dimensional confidence interval at 90% for the phase δ CP spans the range (−3.13, −0.39) for normal mass ordering. The CP conservation hypothesis (δ CP ¼ 0, π) is excluded at 90% C.L.
Geo-neutrinos, electron anti-neutrinos produced in beta decays of naturally occurring radioactive isotopes in the Earth, are a unique direct probe of our planet's interior. We report the first observation at more than 3$\sigma$ C.L. of geo-neutrinos, performed with the Borexino detector at Laboratori Nazionali del Gran Sasso. Anti-neutrinos are detected through the neutron inverse beta decay reaction. With a 252.6 ton-yr fiducial exposure after all selection cuts, we detected 9.9^{+4.1}_{-3.4}(^{+14.6}_{-8.2}) geo-neutrino events, with errors corresponding to a 68.3%(99.73%) C.L. From the $\ln{\cal{L}}$ profile, the statistical significance of the Borexino geo-neutrino observation corresponds to a 99.997% C.L. Our measurement of the geo-neutrinos rate is 3.9^{+1.6}_{-1.3}(^{+5.8}_{-3.2}) events/(100ton-yr). This measurement rejects the hypothesis of an active geo-reactor in the Earth's core with a power above 3 TW at 95% C.L. The observed prompt positron spectrum above 2.6 MeV is compatible with that expected from european nuclear reactors (mean base line of approximately 1000 km). Our measurement of reactor anti-neutrinos excludes the non-oscillation hypothesis at 99.60% C.L
This paper reports measurements of final-state proton multiplicity, muon and proton kinematics, and their correlations in charged-current pionless neutrino interactions, measured by the T2K ND280 near detector in its plastic scintillator (C 8 H 8 ) target. The data were taken between years 2010 and 2013, corresponding to approximately 6 × 10 20 protons on target. Thanks to their exploration of the proton kinematics and of imbalances between the proton and muon kinematics, the results offer a novel probe of the nuclear-medium effects most pertinent to the (sub-)GeV neutrino-nucleus interactions that are used in accelerator-based long-baseline neutrino oscillation measurements. These results are compared to many neutrino-nucleus interaction models which all fail to describe at least part of the observed phase space. In case of events without a proton above a detection threshold in the final state, a fully consistent implementation of the local Fermi gas model with multinucleon interactions gives the best description of the data. In the case of at least one proton in the final state, the spectral function model agrees well with the data, most notably when measuring the kinematic imbalance between the muon and the proton in the plane transverse to the incoming neutrino. Within the models considered, only the existence of multinucleon interactions are able to describe the extracted cross section within regions of high transverse kinematic imbalance. The effect of final-state interactions is also discussed.
We report the measurement of ν-e elastic scattering from 8 B solar neutrinos with 3 MeV energy threshold by the Borexino detector in Gran Sasso (Italy). The rate of solar neutrino-induced electron scattering events above this energy in Borexino is 0.217 ± 0.038(stat) ± 0.008(syst) cpd/100 t, which corresponds to Φ ES 8 B = 2.4 ± 0.4± 0.1×10 6 cm −2 s −1 , in good agreement with measurements from SNO and SuperKamiokaNDE. Assuming the 8 B neutrino flux predicted by the high metallicity Standard Solar Model, the average 8 B νe survival probability above 3 MeV is measured to be 0.29±0.10. The survival probabilities for 7 Be and 8 B neutrinos as measured by Borexino differ by 1.9 σ. These results are consistent with the prediction of the MSW-LMA solution of a transition in the solar νe survival probability Pee between the low energy vacuum-driven and the high-energy matter-enhanced solar neutrino oscillation regimes.PACS numbers: 14.60. St, 26.65.+t, 95.55.Vj, 29.40.Mc INTRODUCTION Solar8 B-neutrino spectroscopy has been so far performed by the waterČerenkov detectors KamiokaNDE, SuperKamiokaNDE,. The first two experiments used elastic ν-e scattering for the detection of neutrinos, whereas SNO also exploited nuclear reaction channels on deuterium with heavy water as target. These experiments provided robust spectral measurements with ∼5 MeV threshold or higher for scattered electrons; a recent SNO analysis reached a 3.5 MeV threshold [5].We report the first observation of solar 8 B-neutrinos with a liquid scintillator detector, performed by the Borexino experiment [6,7] via elastic ν-e scattering. Borexino is the first experiment to succeed in suppressing all major backgrounds, above the 2.614 MeV γ from the decay of 208 Tl, to a rate below that of electron scatterings from solar neutrinos. This allows to reduce the energy threshold for scattered electrons by 8 B solar neutrinos to 3 MeV, the lowest ever reported for the electron scattering channel. To facilitate a comparison to the results of SuperKamiokaNDE [3] and SNO D 2 O phase [4], we also report the measured 8 B neutrino interaction rate with 5 MeV threshold.Since Borexino also detected low energy solar 7 Be neutri-2 nos [8,9], this is the first experiment where both branches of the solar pp-cycle have been measured simultaneously in the same target. The large mixing angle solution (LMA) of the MSW effect [10] predicts a transition in the ν e survival probability from the vacuum oscillation regime at low energies to the matter dominated regime at high energies. Results on solar 7 Be and 8 B neutrinos from Borexino, combined with prediction on the absolute neutrino fluxes from the Standard Solar Model [11][12][13], confirm that our data are in agreement with the MSW-LMA prediction within 1σ. EXPERIMENTAL APPARATUS AND ENERGY THRESHOLDThe Borexino detector is located at the underground Laboratori Nazionali del Gran Sasso (LNGS) in central Italy, at a depth of 3600 m.w.e.. Solar neutrinos are detected in Borexino exclusively via elastic ν-e scattering in a li...
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