The measurement of neutrino mass ordering (MO) is a fundamental element for the understanding of leptonic flavour sector of the Standard Model of Particle Physics. Its determination relies on the ...precise measurement of Formula: see text and Formula: see text using either neutrino vacuum oscillations, such as the ones studied by medium baseline reactor experiments, or matter effect modified oscillations such as those manifesting in long-baseline neutrino beams (LBFormula: see textB) or atmospheric neutrino experiments. Despite existing MO indication today, a fully resolved MO measurement (Formula: see text) is most likely to await for the next generation of neutrino experiments: JUNO, whose stand-alone sensitivity is Formula: see text, or LBFormula: see textB experiments (DUNE and Hyper-Kamiokande). Upcoming atmospheric neutrino experiments are also expected to provide precious information. In this work, we study the possible context for the earliest full MO resolution. A firm resolution is possible even before 2028, exploiting mainly vacuum oscillation, upon the combination of JUNO and the current generation of LBFormula: see textB experiments (NOvA and T2K). This opportunity is possible thanks to a powerful synergy boosting the overall sensitivity where the sub-percent precision of Formula: see text by LBFormula: see textB experiments is found to be the leading order term for the MO earliest discovery. We also found that the comparison between matter and vacuum driven oscillation results enables unique discovery potential for physics beyond the Standard Model.
Using the NuMI beam at Fermilab and the NOvA near detector, we study the process by which a muon neutrino elastically scatters off an electron in the detector to produce a very forward going ...electromagnetic shower. By comparing dE/dx for various particle hypotheses for both longitudinal and transverse directions in a multilayer perceptron neural network, we trained a Particle ID algorithm to identify the scattered electron in an inclusive dataset. Muon-neutrino-on-e elastic scattering provides a clean, purely leptonic process free from nuclear effects for understanding neutral current scattering and constraining the NuMI beam flux. Also, this technique can be applied in two broad areas of beyond the standard model physics: a large neutrino transition magnetic moment and light dark matter particles produced in the NuMI target, both of which would create an energy dependent enhancement in the elastic scattering cross section.
In neutrino experiments, neutrino energy reconstruction is crucial because neutrino oscillations and differential cross-sections are functions of neutrino energy. It is also challenging due to the ...complexity in the detector response and kinematics of final state particles. We propose a regression convolutional neural network (CNN) based method to reconstruct electron neutrino energy and electron energy in the NOvA neutrino experiment. We demonstrate that with raw detector pixel inputs, a regression CNN can reconstruct event energy even with complicated final states involving lepton and hadrons. Compared with kinematics-based energy reconstruction, this method achieves a significantly better energy resolution. The reconstructed to true energy ratio shows comparable or less dependence on true energy, hadronic energy fractions, and interaction modes. The regression CNN also shows smaller systematic uncertainties from the simulation of neutrino interactions. The proposed energy estimator provides improvements of 16% and 12% in RMS for νe CC and electron, respectively. This method can also be extended to solve other regression problems in High Energy Physics, taking over kinematics-based reconstruction tasks.
The unified approach of Feldman and Cousins allows for exact statistical inference of small signals that commonly arise in high energy physics. It has gained widespread use, for instance, in ...measurements of neutrino oscillation parameters in long-baseline experiments. However, the approach relies on the Neyman construction of the classical confidence interval and is computationally intensive as it is typically done in a grid-based fashion over the entire parameter space. In this article, we propose an efficient algorithm for the Feldman-Cousins approach using Gaussian processes to construct confidence intervals iteratively. We show that in the neutrino oscillation context, one can obtain confidence intervals fives times faster in one dimension and ten times faster in two dimensions, while maintaining an accuracy above 99.5%.
We introduce the absolute energy calibration of the electromagnetic calorimeter at BESIII. The precision after calibration is about 0.5% and the resolution difference between data and the simulation ...is about 5%. We also present a method to veto beam-gas background using the timing information of the EMC, which is crucial for physics analyses involving low energy photons at BESIII.
NOvA is a long-baseline neutrino experiment that uses an upgraded NuMI neutrino source at Fermilab and a 14-kton detector at Ash River, Minnesota. The detector has a highly active, finely segmented ...design that offers superb event identification capability. This talk presents the latest \(\nu_\mu\) (\(\bar{\nu}_\mu\)) disappearance and \(\nu_e\) (\(\bar{\nu}_e\)) appearance combined results using the first NOvA anti-neutrino beam data. In the far detector, 18 \(\bar{\nu}_e\) candidate events are observed, with a significance of \(\bar{\nu}_e\) appearance more than 4 \(\sigma\). The NOvA results favor a normal neutrino mass hierarchy.
NOvA is a long-baseline accelerator-based neutrino oscillation experiment that is optimized for electron-neutrino appearance measurements. It uses the upgraded NuMI beam from Fermilab and consists of ...a Far Detector in Ash River, Minnesota and a Near Detector at Fermilab. An accurate prediction of the neutrino flux is key to both oscillation and cross-section measurements. The precisely known neutrino-electron elastic scattering cross section provides an in situ constraint on the absolute flux. This talk discusses the status of the measurement of the rate of neutrino-electron elastic scattering in the NOvA Near Detector.
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