T2K Collaboration(Abe, K. et al), Antonova, M., Cervera-Villanueva, A., Molina Bueno, L., & Novella, P. (2023). Measurements of the νμ and bar(ν)μ-induced coherent charged pion production cross sections on 12C by the T2K experiment. Phys. Rev. D, 108(9), 092009–15pp.
Abstract: We report an updated measurement of the nu(mu)-induced, and the first measurement of the (nu) over bar (mu)- induced coherent charged pion production cross section on C-12 nuclei in the Tokai-to-Kamioka experiment. This is measured in a restricted region of the final- state phase space for which p(mu,pi) > 0.2 GeV, cos(theta(mu)) > 0.8 and cos(theta(pi)) > 0.6, and at a mean ( anti)neutrino energy of 0.85 GeVusing the T2K near detector. The measured nu(mu) charged current coherent pion production flux-averaged cross section on C-12 is (2.98 +/- 0.37(stat) +/- 0.31(syst)(-0.00)(+0.49)(Q(2) model)) x 10(-40) cm(2). The new measurement of the (nu) over bar (mu)-induced cross section on C-12 is (3.05 +/- 0.71(stat) +/- 0.39(syst)(-0.00)(+-0.74) (Q(2) model)) x 10(-40) cm(2). The results are compatible with both the NEUT 5.4.0 Berger-Sehgal (2009) and GENIE 2.8.0 Rein-Sehgal (2007) model predictions.
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DUNE Collaboration(Abud, A. A. et al), Amedo, P., Antonova, M., Barenboim, G., Cervera-Villanueva, A., De Romeri, V., et al. (2023). Identification and reconstruction of low-energy electrons in the ProtoDUNE-SP detector. Phys. Rev. D, 107(9), 092012–22pp.
Abstract: Measurements of electrons from ?e interactions are crucial for the Deep Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as searches for physics beyond the standard model, supernova neutrino detection, and solar neutrino measurements. This article describes the selection and reconstruction of low-energy (Michel) electrons in the ProtoDUNE-SP detector. ProtoDUNE-SP is one of the prototypes for the DUNE far detector, built and operated at CERN as a charged particle test beam experiment. A sample of low-energy electrons produced by the decay of cosmic muons is selected with a purity of 95%. This sample is used to calibrate the low-energy electron energy scale with two techniques. An electron energy calibration based on a cosmic ray muon sample uses calibration constants derived from measured and simulated cosmic ray muon events. Another calibration technique makes use of the theoretically well-understood Michel electron energy spectrum to convert reconstructed charge to electron energy. In addition, the effects of detector response to low-energy electron energy scale and its resolution including readout electronics threshold effects are quantified. Finally, the relation between the theoretical and reconstructed low-energy electron energy spectra is derived, and the energy resolution is characterized. The low-energy electron selection presented here accounts for about 75% of the total electron deposited energy. After the addition of lost energy using a Monte Carlo simulation, the energy resolution improves from about 40% to 25% at 50 MeV. These results are used to validate the expected capabilities of the DUNE far detector to reconstruct low-energy electrons.
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Bayes, R., Laing, A., Soler, F. J. P., Cervera-Villanueva, A., Gomez-Cadenas, J. J., Hernandez, P., et al. (2012). Golden channel at a neutrino factory revisited: Improved sensitivities from a magnetized iron neutrino detector. Phys. Rev. D, 86(9), 093015–27pp.
Abstract: This paper describes the performance and sensitivity to neutrino mixing parameters of a Magnetised Iron Neutrino Detector at a Neutrino Factory with a neutrino beam created from the decay of 10 GeV muons. Specifically, it is concerned with the ability of such a detector to detect muons of the opposite sign to those stored (wrong-sign muons) while suppressing contamination of the signal from the interactions of other neutrino species in the beam. A new, more realistic simulation and analysis, which improves the efficiency of this detector at low energies, has been developed using the GENIE neutrino event generator and the GEANT4 simulation toolkit. Low-energy neutrino events down to 1 GeV were selected, while reducing backgrounds to the 10(-4) level. Signal efficiency plateaus of similar to 60% for nu(mu) and similar to 70% for (nu) over bar (mu) events were achieved starting at similar to 5 GeV. Contamination from the nu(mu) -> nu(tau) oscillation channel was studied for the first time and was found to be at the level between 1% and 4%. Full response matrices are supplied for all the signal and background channels from 1 GeV to 10 GeV. The sensitivity of an experiment involving a Magnetised Iron Neutrino Detector detector of 100 ktons at 2000 km from the Neutrino Factory is calculated for the case of sin(2)2 theta(13) similar to 10(-1). For this value of theta(13), the accuracy in the measurement of the CP-violating phase is estimated to be Delta delta(CP) similar to 3 degrees-5 degrees, depending on the value of delta(CP), the CP coverage at 5 sigma is 85% and the mass hierarchy would be determined with better than 5 sigma level for all values of delta(CP).
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T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Izmaylov, A., Novella, P., Sorel, M., & Stamoulis, P. (2017). Search for Lorentz and CPT violation using sidereal time dependence of neutrino flavor transitions over a short baseline. Phys. Rev. D, 95(11), 111101–9pp.
Abstract: A class of extensions of the Standard Model allows Lorentz and CPT violations, which can be identified by the observation of sidereal modulations in the neutrino interaction rate. A search for such modulations was performed using the T2K on-axis near detector. Two complementary methods were used in this study, both of which resulted in no evidence of a signal. Limits on associated Lorentz and CPT-violating terms from the Standard Model extension have been derived by taking into account their correlations in this model for the first time. These results imply such symmetry violations are suppressed by a factor of more than 10(20) at the GeV scale.
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T2K Collaboration(Abe, K. et al), Antonova, M., Cervera-Villanueva, A., Fernandez, P., Izmaylov, A., & Novella, P. (2020). First combined measurement of the muon neutrino and antineutrino charged-current cross section without pions in the final state at T2K. Phys. Rev. D, 101(11), 112001–44pp.
Abstract: This paper presents the first combined measurement of the double-differential muon neutrino and antineutrino charged-current cross sections with no pions in the final state on hydrocarbon at the off-axis near detector of the T2K experiment. The data analyzed in this work comprise 5.8 x 10(20) and 6.3 x 10(20) protons on target in neutrino and antineutrino mode respectively, at a beam energy peak of 0.6 GeV. Using the two measured cross sections, the sum, difference, and asymmetry were calculated with the aim of better understanding the nuclear effects involved in such interactions. The extracted measurements have been compared with the prediction from different Monte Carlo generators and theoretical models showing that the difference between the two cross sections have interesting sensitivity to nuclear effects.
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