اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMultiple Detectors for a Short-Baseline Neutrino Oscillation Search Near Reactors
134
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Reactor antineutrino experiments have the ability to search for neutrino oscillations independent of reactor flux predictions using a relative measurement of the neutrino flux and spectrum across a range of baselines. The range of accessible oscillation parameters are determined by the baselines of the detector arrangement. We examine the sensitivity of short-baseline experiments with more than one detector and discuss the optimization of a second, far detector. The extended reach in baselines of a 2-detector experiment will improve sensitivity to short-baseline neutrino oscillations while also increasing the ability to distinguish between 3+1 mixing and other non-standard models.
قيم البحث
اقرأ أيضاً
The Deep Underground Neutrino Experiment (DUNE) will produce world-leading neutrino oscillation measurements over the lifetime of the experiment. In this work, we explore DUNEs sensitivity to observe charge-parity violation (CPV) in the neutrino sect
or, and to resolve the mass ordering, for exposures of up to 100 kiloton-megawatt-years (kt-MW-yr). The analysis includes detailed uncertainties on the flux prediction, the neutrino interaction model, and detector effects. We demonstrate that DUNE will be able to unambiguously resolve the neutrino mass ordering at a 3$sigma$ (5$sigma$) level, with a 66 (100) kt-MW-yr far detector exposure, and has the ability to make strong statements at significantly shorter exposures depending on the true value of other oscillation parameters. We also show that DUNE has the potential to make a robust measurement of CPV at a 3$sigma$ level with a 100 kt-MW-yr exposure for the maximally CP-violating values $delta_{rm CP}} = pmpi/2$. Additionally, the dependence of DUNEs sensitivity on the exposure taken in neutrino-enhanced and antineutrino-enhanced running is discussed. An equal fraction of exposure taken in each beam mode is found to be close to optimal when considered over the entire space of interest.
In the past decade, the precise measurement of the lastly known neutrino mixing angle $theta_{13}$ has enabled the resolution of neutrino mass hierarchy (MH) at medium-baseline reactor neutrino oscillation (MBRO) experiments. On the other hand, recen
t calculations of the reactor neutrino flux predict percent-level sub-structures in the $bar u_e$ spectrum due to Coulomb effects in beta decay. Such fine structure in the reactor spectrum could be an important issue for the determination of neutrino MH for the MBRO approach since they could affect the sub-dominant oscillation pattern used to discriminate different hierarchies. Inconveniently, the energy resolutions of current reactor experiments are not sufficient to measure such fine structure, and therefore the size and location in energy of these predicted discontinuities has not been confirmed experimentally. There has been speculation that a near detector is required with sufficient energy resolution to resolve the fine structure such that it can be accounted for in any analysis which attempts to discriminate the MH. This article studies the impact of fine structure on the resolution of MH, based on the predicted reactor neutrino spectra, using the measured spectrum from Daya Bay as a reference. We also investigate whether a near detector could improve the sensitivity of neutrino MH resolution using various assumptions of near detector energy resolution.
We present the results of the Neutrino-4 experiment on search for a sterile neutrino. The experiment has been carried out on the SM-3 reactor having a compact active zone of $42times42times35textrm{cm}^3$ and operating on the highly enriched uranium-
235 at 90 MW thermal power. We report the results of the Neutrino-4 experiment of measurements of reactor antineutrino flux and spectrum dependence on the distance in the range 6-12 meters from the center of the reactor core. Using the measured spectrum and the distance dependence of antineutrino flux, we performed the model independent analysis of restrictions on the oscillation parameters $Delta m^2_{14}$ and $sin^2 2theta_{14}$. The method of coherent addition of results of measurements is proposed. It allows us to directly observe the effect of oscillations. We observed the oscillation effect at CL $3.5sigma$ in the vicinity of $Delta m^2_{14} approx 7.26textrm{eV}^2$ and $sin^2 2theta_{14} approx 0.38$. Combining the result of the Neutrino-4 experiment and the result of the gallium anomaly effect we obtained value $sin^2 2theta_{14} approx 0.35 pm 0.07 (5sigma)$. The analysis of systematics effects is presented. Comparison with results of other experiments is presented. Future prospect of the experiment is discussed. It is necessary to notice that obtained values $sin^2 2theta_{14} approx 0.35 pm 0.07 (5sigma)$ and $Delta m^2_{14} approx (7.3 pm 0.7)textrm{eV}^2$ allow make assessment on the mass of a neutrino: $m_{beta} approx 0.8textrm{eV}$.
For a long time there were 3 main experimental indications in favor of the existence of sterile neutrinos: $bar{ u_e}$ appearance in the $bar{ u_mu}$ beam in the LSND experiment, $bar{ u_e}$ flux deficit in comparison with theoretical expectations in
reactor experiments, and $ u_e$ deficit in calibration runs with radioactive sources in the Ga solar neutrino experiments SAGE and GALEX. All three problems can be explained by the existence of sterile neutrinos with the mass square difference in the ballpark of $1~mathrm{eV^2}$. Recently the MiniBooNE collaboration observed electron (anti)neutrino appearance in the muon (anti)neutrino beams. The significance of the effect reaches 6.0$sigma$ level when combined with the LSND result. Even more recently the NEUTRINO-4 collaboration claimed the observation of $bar{ u_e}$ oscillations to sterile neutrinos with a significance slightly higher than 3$sigma$. If these results are confirmed, New Physics beyond the Standard Model would be required. More than 10 experiments are devoted to searches of sterile neutrinos. Six very short baseline reactor experiments are taking data just now. We review the present results and perspectives of these experiments.
We present a detailed report on sterile neutrino oscillation and U-235 antineutrino energy spectrum measurement results from the PROSPECT experiment at the highly enriched High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. In 96 calen
dar days of data taken at an average baseline distance of 7.9 m from the center of the 85 MW HFIR core, the PROSPECT detector has observed more than 50,000 interactions of antineutrinos produced in beta decays of U-235 fission products. New limits on the oscillation of antineutrinos to light sterile neutrinos have been set by comparing the detected energy spectra of ten reactor-detector baselines between 6.7 and 9.2 meters. Measured differences in energy spectra between baselines show no statistically significant indication of antineutrinos to sterile neutrino oscillation and disfavor the Reactor Antineutrino Anomaly best-fit point at the 2.5$sigma$ confidence level. The reported U-235 antineutrino energy spectrum measurement shows excellent agreement with energy spectrum models generated via conversion of the measured U-235 beta spectrum, with a $chi^2$/DOF of 31/31. PROSPECT is able to disfavor at 2.4$sigma$ confidence level the hypothesis that U-235 antineutrinos are solely responsible for spectrum discrepancies between model and data obtained at commercial reactor cores. A data-model deviation in PROSPECT similar to that observed by commercial core experiments is preferred with respect to no observed deviation, at a 2.2$sigma$ confidence level.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
