We present new \(\nu_\mu\rightarrow\nu_e\), \(\nu_\mu\rightarrow\nu_\mu\), \(\overline{\nu}_\mu\rightarrow\overline{\nu}_e\), and \(\overline{\nu}_\mu\rightarrow\overline{\nu}_\mu\) oscillation ...measurements by the NOvA experiment, with a 50% increase in neutrino-mode beam exposure over the previously reported results. The additional data, combined with previously published neutrino and antineutrino data, are all analyzed using improved techniques and simulations. A joint fit to the \(\nu_e\), \(\nu_\mu\), \(\overline{\nu}_e\), and \(\overline{\nu}_\mu\) candidate samples within the 3-flavor neutrino oscillation framework continues to yield a best-fit point in the normal mass ordering and the upper octant of the \(\theta_{23}\) mixing angle, with \(\Delta m^{2}_{32} = (2.41\pm0.07)\times 10^{-3}\) eV\(^2\) and \(\sin^2\theta_{23} = 0.57^{+0.03}_{-0.04}\). The data disfavor combinations of oscillation parameters that give rise to a large asymmetry in the rates of \(\nu_e\) and \(\overline{\nu}_e\) appearance. This includes values of the CP-violating phase in the vicinity of \(\delta_\text{CP} = \pi/2\) which are excluded by \(>3\sigma\) for the inverted mass ordering, and values around \(\delta_\text{CP} = 3\pi/2\) in the normal ordering which are disfavored at 2\(\sigma\) confidence.
Measuring observables to constrain models using maximum-likelihood estimation is fundamental to many physics experiments. The Profiled Feldman-Cousins method described here is a potential solution to ...common challenges faced in constructing accurate confidence intervals: small datasets, bounded parameters, and the need to properly handle nuisance parameters. This method achieves more accurate frequentist coverage than other methods in use, and is generally applicable to the problem of parameter estimation in neutrino oscillations and similar measurements. We describe an implementation of this method in the context of the NOvA experiment.
The inclusive electron neutrino charged-current cross section is measured in
the NOvA near detector using $8.02\times10^{20}$ protons-on-target (POT) in the
NuMI beam. The sample of GeV electron ...neutrino interactions is the largest
analyzed to date and is limited by $\simeq$ 17\% systematic rather than the
$\simeq$ 7.4\% statistical uncertainties. The double-differential cross section
in final-state electron energy and angle is presented for the first time,
together with the single-differential dependence on $Q^{2}$ (squared
four-momentum transfer) and energy, in the range 1 GeV $ \leq E_{\nu} < $6 GeV.
Detailed comparisons are made to the predictions of the GENIE, GiBUU, NEUT, and
NuWro neutrino event generators. The data do not strongly favor a model over
the others consistently across all three cross sections measured, though some
models have especially good or poor agreement in the single differential cross
section vs. $Q^{2}$.
This Letter reports the first measurement of high-energy reactor antineutrinos at Daya Bay, with nearly 9000 inverse beta decay candidates in the prompt energy region of 8-12~MeV observed over 1958 ...days of data collection. A multivariate analysis is used to separate 2500 signal events from background statistically. The hypothesis of no reactor antineutrinos with neutrino energy above 10~MeV is rejected with a significance of 6.2 standard deviations. A 29\% antineutrino flux deficit in the prompt energy region of 8-11~MeV is observed compared to a recent model prediction. We provide the unfolded antineutrino spectrum above 7 MeV as a data-based reference for other experiments. This result provides the first direct observation of the production of antineutrinos from several high-\(Q_{\beta}\) isotopes in commercial reactors.
This Letter reports results from the first long-baseline search for sterile antineutrinos mixing in an accelerator-based antineutrino-dominated beam. The rate of neutral-current interactions in the ...two NOvA detectors, at distances of 1 km and 810 km from the beam source, is analyzed using an exposure of \(12.51\times10^{20}\) protons-on-target from the NuMI beam at Fermilab running in antineutrino mode. A total of \(121\) of neutral-current candidates are observed at the Far Detector, compared to a prediction of \(122\pm11\)(stat.)\(\pm15\)(syst.) assuming mixing between three active flavors. No evidence for \(\bar{\nu}_{\mu}\rightarrow\bar{\nu}_{s}\) oscillation is observed. Interpreting this result within a 3+1 model, constraints are placed on the mixing angles \({\theta}_{24} < 25^{\circ}\) and \({\theta}_{34} < 32^{\circ}\) at the 90% C.L. for \(0.05\)eV\(^{2} \leq \Delta m^{2}_{41} \leq 0.5\)eV\(^{2}\), the range of mass splittings that produces no significant oscillations at the Near Detector. These are the first 3+1 confidence limits set using long-baseline accelerator antineutrinos.
A search is performed for supernova-like neutrino interactions coincident with 76 gravitational wave events detected by the LIGO/Virgo Collaboration. For 40 of these events, full readout of the time ...around the gravitational wave is available from the NOvA Far Detector. For these events, we set limits on the fluence of the sum of all neutrino flavors of \(F < 7(4)\times 10^{10}\mathrm{cm}^{-2}\) at 90% C.L. assuming energy and time distributions corresponding to the Garching supernova models with masses 9.6(27)\(\mathrm{M}_\odot\). Under the hypothesis that any given gravitational wave event was caused by a supernova, this corresponds to a distance of \(r > 29(50)\)kpc at 90% C.L. Weaker limits are set for other gravitational wave events with partial Far Detector data and/or Near Detector data.
We report the rate of cosmic ray air showers with multiplicities exceeding 15 muon tracks recorded in the NOvA Far Detector between May 2016 and May 2018. The detector is located on the surface under ...an overburden of 3.6 meters water equivalent. We observe a seasonal dependence in the rate of multiple-muon showers, which varies in magnitude with multiplicity and zenith angle. During this period, the effective atmospheric temperature and surface pressure ranged between 210 K to 230 K and 940mbar to 990mbar, respectively; the shower rates are anti-correlated with the variation in the effective temperature. The variations are about 30% larger for the highest multiplicities than the lowest multiplicities and 20% larger for showers near the horizon than vertical showers.
PANDA Phase One Davì, F; Montalto, L; Krusche, B ...
arXiv.org,
06/2021
Paper, Journal Article
Odprti dostop
The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of hadron-, nuclear- and atomic physics experiments. The future ...antiProton ANnihilations at DArmstadt (PANDA or \(\overline{\rm P}\)ANDA) experiment at FAIR will offer a broad physics programme, covering different aspects of the strong interaction. Understanding the latter in the non-perturbative regime remains one of the greatest challenges in contemporary physics. The antiproton-nucleon interaction studied with PANDA provides crucial tests in this area. Furthermore, the high-intensity, low-energy domain of PANDA allows for searches for physics beyond the Standard Model, e.g. through high precision symmetry tests. This paper takes into account a staged approach for the detector setup and for the delivered luminosity from the accelerator. The available detector setup at the time of the delivery of the first antiproton beams in the HESR storage ring is referred to as the \textit{Phase One} setup. The physics programme that is achievable during Phase One is outlined in this paper.
Using the NOvA neutrino detectors, a broad search has been performed for any signal coincident with 28 gravitational wave events detected by the LIGO/Virgo Collaboration between September 2015 and ...July 2019. For all of these events, NOvA is sensitive to possible arrival of neutrinos and cosmic rays of GeV and higher energies. For five (seven) events in the NOvA Far (Near) Detector, timely public alerts from the LIGO/Virgo Collaboration allowed recording of MeV-scale events. No signal candidates were found.
The prediction of reactor antineutrino spectra will play a crucial role as reactor experiments enter the precision era. The positron energy spectrum of 3.5 million antineutrino inverse beta decay ...reactions observed by the Daya Bay experiment, in combination with the fission rates of fissile isotopes in the reactor, is used to extract the positron energy spectra resulting from the fission of specific isotopes. This information can be used to produce a precise, data-based prediction of the antineutrino energy spectrum in other reactor antineutrino experiments with different fission fractions than Daya Bay. The positron energy spectra are unfolded to obtain the antineutrino energy spectra by removing the contribution from detector response with the Wiener-SVD unfolding method. Consistent results are obtained with other unfolding methods. A technique to construct a data-based prediction of the reactor antineutrino energy spectrum is proposed and investigated. Given the reactor fission fractions, the technique can predict the energy spectrum to a 2% precision. In addition, we illustrate how to perform a rigorous comparison between the unfolded antineutrino spectrum and a theoretical model prediction that avoids the input model bias of the unfolding method.
