The Super-Kamiokande and T2K Collaborations present a joint measurement of neutrino oscillation parameters from their atmospheric and beam neutrino data. It uses a common interaction model for events overlapping in neutrino energy and correlated detector systematic uncertainties between the two datasets, which are found to be compatible. Using 3244.4 days of atmospheric data and a beam exposure of 19.7(16.3)×1020 protons on target in (anti)neutrino mode, the analysis finds a 1.9σ exclusion of CP conservation (defined as JCP=0) and a 1.2σ exclusion of the inverted mass ordering. Published by the American Physical Society 2025

Measurements of K_S^0 meson production via its π^+π^- decay mode in inelastic p+p interactions at incident projectile momenta of 31, 40 and 80 GeV/c (√(s_NN)=7.7, 8.8 and 12.3 GeV, respectively) are presented. The data were recorded by the NA61/SHINE spectrometer at the CERN Super Proton Synchrotron. Double-differential distributions were obtained in transverse momentum and rapidity. The mean multiplicities of K_S^0 mesons were determined to be (5.95 ± 0.19 (stat) ± 0.22 (sys)) × 10^-2 at 31 GeV/c, (7.61 ± 0.13 (stat) ± 0.31 (sys)) × 10^-2 at 40 GeV/c and (11.58 ± 0.12 (stat) ± 0.37 (sys)) × 10^-2 at 80 GeV/c. The results on K^0_S production are compared with model calculations (Epos1.99, SMASH 2.0 and PHSD) as well as with published data from other experiments.

Abstract The yields of $$K^0_S$$ K S 0 mesons have been measured in inelastic p+p interactions at incident projectile momenta of 31, 40 and 80 $$\text {Ge}\hspace{-1.00006pt}\text {V}\!/\!c$$ Ge V / c ( $$\sqrt{s_{NN}}=7.7, 8.8$$ s NN = 7.7 , 8.8 and 12.3 $$\text {Ge}\hspace{-1.00006pt}\text {V}$$ Ge V , respectively). The data were recorded by the NA61 $$/$$ / SHINE spectrometer at the CERN Super Proton Synchrotron and the $$K^0_S$$ K S 0 mesons identified via their decays into $$\pi ^{+} \pi ^{-}$$ π + π - pairs. Double-differential distributions are presented as function of transverse momentum and rapidity. The mean multiplicities of $$K^0_S$$ K S 0 mesons were determined to be $$(5.95 \pm 0.19 (stat) \pm 0.30 (sys)) \times 10^{-2}$$ ( 5.95 ± 0.19 ( s t a t ) ± 0.30 ( s y s ) ) × 10 - 2 at 31 $$\text {Ge}\hspace{-1.00006pt}\text {V}\!/\!c$$ Ge V / c , $$(7.61 \pm 0.13 (stat) \pm 0.43 (sys)) \times 10^{-2}$$ ( 7.61 ± 0.13 ( s t a t ) ± 0.43 ( s y s ) ) × 10 - 2 at 40 $$\text {Ge}\hspace{-1.00006pt}\text {V}\!/\!c$$ Ge V / c and $$(11.58 \pm 0.12 (stat) \pm 0.55 (sys)) \times 10^{-2}$$ ( 11.58 ± 0.12 ( s t a t ) ± 0.55 ( s y s ) ) × 10 - 2 at 80 $$\text {Ge}\hspace{-1.00006pt}\text {V}\!/\!c$$ Ge V / c . The results on $$K^{0}_{S}$$ K S 0 production are compared with the production of charged kaons in corresponding reactions and with model calculations (Epos1.99, SMASH 2.0 and PHSD) as well as with published data from other experiments.

The yields of K^0_S mesons have been measured in inelastic p+p interactions at incident projectile momenta of 31, 40 and 80 GeV/c ( √(s_NN)=7.7, 8.8 and 12.3 GeV , respectively). The data were recorded by the NA61 / SHINE spectrometer at the CERN Super Proton Synchrotron and the K^0_S mesons identified via their decays into π ^+π ^- pairs. Double-differential distributions are presented as function of transverse momentum and rapidity. The mean multiplicities of K^0_S mesons were determined to be (5.95 ± 0.19 (stat) ± 0.30 (sys)) × 10^-2 at 31 GeV/c , (7.61 ± 0.13 (stat) ± 0.43 (sys)) × 10^-2 at 40 GeV/c and (11.58 ± 0.12 (stat) ± 0.55 (sys)) × 10^-2 at 80 GeV/c . The results on K^0_S production are compared with the production of charged kaons in corresponding reactions and with model calculations (Epos1.99, SMASH 2.0 and PHSD) as well as with published data from other experiments.

We present the development and discuss the performance of a compact scintillating fiber detector for the Mu3e experiment for accurate time measurements at very high particle rates. Mu3e is a new experiment under preparation at the Paul Scherrer Institut (PSI) to search for charged Lepton Flavor Violation in the neutrinoless muon decay μ+→e+e−e+ with a projected sensitivity of 10−16 using the most intense continuous surface muon beam in the world. A very thin scintillating fiber detector (thickness <0.2% of a radiation length X0) with a time resolution of about 250 ps, efficiency around 97%, and spatial resolution of ∼100μm has been developed. The SciFi detector is read out with multi-channel silicon photomultiplier arrays at both ends to achieve the best timing performance. Different scintillating fiber types have been evaluated and various assembly procedures have been tested to achieve the best performance.

Accelerator based neutrino oscillation experiments seek to measure the relative number of electron and muon (anti)neutrinos at different L/E values. However high statistics studies of neutrino interactions are almost exclusively measured using muon (anti)neutrinos since the dominant flavor of neutrinos produced by accelerator based beams are of the muon type. This work reports new measurements of electron (anti)neutrinos interactions in hydrocarbon, obtained by strongly suppressing backgrounds initiated by muon flavor (anti)neutrinos. Double differential cross sections as a function of visible energy transfer, Eavail, and transverse momentum transfer, pT, or three momentum transfer, q3 are presented. Published by the American Physical Society 2024

AbstractThe yields of $$K^0_S$$ K S 0 mesons have been measured in inelastic p+p interactions at incident projectile momenta of 31, 40 and 80 $$\text {Ge}\hspace{-1.00006pt}\text {V}\!/\!c$$ Ge V / c ($$\sqrt{s_{NN}}=7.7, 8.8$$ s NN = 7.7 , 8.8 and 12.3 $$\text {Ge}\hspace{-1.00006pt}\text {V}$$ Ge V , respectively). The data were recorded by the NA61$$/$$ / SHINE spectrometer at the CERN Super Proton Synchrotron and the $$K^0_S$$ K S 0 mesons identified via their decays into $$\pi ^{+} \pi ^{-}$$ π + π - pairs. Double-differential distributions are presented as function of transverse momentum and rapidity. The mean multiplicities of $$K^0_S$$ K S 0 mesons were determined to be $$(5.95 \pm 0.19 (stat) \pm 0.30 (sys)) \times 10^{-2}$$ ( 5.95 ± 0.19 ( s t a t ) ± 0.30 ( s y s ) ) × 10 - 2 at 31 $$\text {Ge}\hspace{-1.00006pt}\text {V}\!/\!c$$ Ge V / c , $$(7.61 \pm 0.13 (stat) \pm 0.43 (sys)) \times 10^{-2}$$ ( 7.61 ± 0.13 ( s t a t ) ± 0.43 ( s y s ) ) × 10 - 2 at 40 $$\text {Ge}\hspace{-1.00006pt}\text {V}\!/\!c$$ Ge V / c and $$(11.58 \pm 0.12 (stat) \pm 0.55 (sys)) \times 10^{-2}$$ ( 11.58 ± 0.12 ( s t a t ) ± 0.55 ( s y s ) ) × 10 - 2 at 80 $$\text {Ge}\hspace{-1.00006pt}\text {V}\!/\!c$$ Ge V / c . The results on $$K^{0}_{S}$$ K S 0 production are compared with the production of charged kaons in corresponding reactions and with model calculations (Epos1.99, SMASH 2.0 and PHSD) as well as with published data from other experiments.

Neutrino-induced charged-current single ${\ensuremath{\pi}}^{+}$ production in the $\mathrm{\ensuremath{\Delta}}(1232)$ resonance region is of considerable interest to accelerator-based neutrino oscillation experiments. In this Letter, high statistic differential cross sections are reported for the semiexclusive reaction ${\ensuremath{\nu}}_{\ensuremath{\mu}}A\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}+$ nucleon(s) on scintillator, carbon, water, iron, and lead targets recorded by MINERvA using a wideband ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ beam with $⟨{E}_{\ensuremath{\nu}}⟩\ensuremath{\approx}6\text{ }\text{ }\mathrm{GeV}$. Suppression of the cross section at low ${Q}^{2}$ and enhancement of low ${T}_{\ensuremath{\pi}}$ are observed in both light and heavy nuclear targets compared with phenomenological models used in current neutrino interaction generators. The cross sections per nucleon for iron and lead compared with CH across the kinematic variables probed are 0.8 and 0.5 respectively, a scaling which is also not predicted by current generators.

We present a measurement of the momentum spectra of ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, ${\mathrm{K}}^{\ifmmode\pm\else\textpm\fi{}}$, ${\mathrm{p}}^{\ifmmode\pm\else\textpm\fi{}}$, $\mathrm{\ensuremath{\Lambda}}$, $\overline{\mathrm{\ensuremath{\Lambda}}}$, and ${\mathrm{K}}_{\mathrm{S}}^{0}$ produced in interactions of negatively charged pions with carbon nuclei at beam momenta of 158 and $350\text{ }\text{ }\mathrm{GeV}/c$. The total production cross sections are measured as well. The data were collected with the large-acceptance spectrometer of the fixed target experiment NA61/SHINE at the CERN SPS. The obtained double-differential $p\text{\ensuremath{-}}{p}_{\mathrm{T}}$ spectra provide a unique reference dataset with unprecedented precision and large phase-space coverage to tune models used for the simulation of particle production in extensive air showers in which pions are the most numerous projectiles.

Processes with precisely known cross sections, like neutrino-electron elastic scattering (ve- -ve-) and inverse muon decay (vise- -is-ve) have been used by MINERvA to constrain the uncertainty on the neutrinos at the main injector (NuMI) neutrino beam flux. This work presents a new measurement of neutrino elastic scattering with electrons using the medium energy v over line o-enhanced NuMI beam. A sample of 578 events after background subtraction is used in combination with the previous measurement on the vo beam and the inverse muon decay measurement to reduce the uncertainty on the vo flux in the vo-enhanced beam from 7.6% to 3.3% and the v over line o flux in the v over line o-enhanced beam from 7.8% to 4.7%.

MINERvA has measured the ν_{μ}-induced coherent π^{+} cross section simultaneously in hydrocarbon (CH), graphite (C), iron (Fe), and lead (Pb) targets using neutrinos from 2 to 20 GeV. The measurements exceed the predictions of the Rein-Sehgal and Berger-Sehgal PCAC based models at multi-GeV ν_{μ} energies and at produced π^{+} energies and angles, E_{π}>1 GeV and θ_{π}<10°. Measurements of the cross-section ratios of Fe and Pb relative to CH reveal the effective A scaling to increase from an approximate A^{1/3} scaling at few GeV to an A^{2/3} scaling for E_{ν}>10 GeV.

This paper presents the first simultaneous measurement of the quasielastic-like neutrino-nucleus cross sections on C, water, Fe, Pb and scintillator (hydrocarbon or CH) as a function of longitudinal and transverse muon momentum. The ratio of cross sections per nucleon between Pb and CH is always above unity and has a characteristic shape as a function of transverse muon momentum that evolves slowly as a function of longitudinal muon momentum. The ratio is constant versus longitudinal momentum within uncertainties above a longitudinal momentum of 4.5GeV/c. The cross section ratios to CH for C, water, and Fe remain roughly constant with increasing longitudinal momentum, and the ratios between water or C to CH do not have any significant deviation from unity. Both the overall cross section level and the shape for Pb and Fe as a function of transverse muon momentum are not reproduced by current neutrino event generators. These measurements provide a direct test of nuclear effects in quasielastic-like interactions, which are major contributors to long-baseline neutrino oscillation data samples.

This paper presents multiplicity measurements of K0S, A, and A over bar produced in 120 GeV=c proton-carbon interactions. The measurements were made using data collected at the NA61/SHINE experiment during two different periods. Decays of these neutral hadrons impact the measured x+, x-, p and p over bar multiplicities in the 120 GeV=c proton-carbon reaction, which are crucial inputs for long-baseline neutrino experiment predictions of neutrino beam flux. The double-differential multiplicities presented here will be used to more precisely measure charged-hadron multiplicities in this reaction, and to reweight neutral hadron production in neutrino beam Monte Carlo simulations.

Muon neutrino and antineutrino disappearance probabilities are identical in the standard three-flavor neutrino oscillation framework, but CPT violation and non-standard interactions can violate this symmetry. In this work we report the measurements of $\sin^{2} \theta_{23}$ and $\Delta m_{32}^2$ independently for neutrinos and antineutrinos. The aforementioned symmetry violation would manifest as an inconsistency in the neutrino and antineutrino oscillation parameters. The analysis discussed here uses a total of 1.97$\times$10$^{21}$ and 1.63$\times$10$^{21}$ protons on target taken with a neutrino and antineutrino beam respectively, and benefits from improved flux and cross-section models, new near detector samples and more than double the data reducing the overall uncertainty of the result. No significant deviation is observed, consistent with the standard neutrino oscillation picture.

We report an updated measurement of the $\nu_{\mu}$-induced, and the first measurement of the $\bar{\nu}_{\mu}$-induced coherent charged pion production cross section on $^{12}C$ nuclei in the T2K 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 GeV using the T2K near detector. The measured $\nu_{\mu}$ CC coherent pion production flux-averaged cross section on $^{12}C$ is $(2.98 \pm 0.37 (stat.) \pm 0.31 (syst.) \substack{ +0.49 \\ -0.00 } \mathrm{ (Q^2\,model)}) \times 10^{-40}~\mathrm{cm}^{2}$. The new measurement of the $\bar{\nu}_{\mu}$-induced cross section on $^{12}{C}$ is $(3.05 \pm 0.71 (stat.) \pm 0.39 (syst.) \substack{ +0.74 \\ -0.00 } \mathrm{(Q^2\,model)}) \times 10^{-40}~\mathrm{cm}^{2}$. The results are compatible with both the NEUT 5.4.0 Berger-Sehgal (2009) and GENIE 2.8.0 Rein-Sehgal (2007) model predictions.

The NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) studies the onset of deconfinement in hadron matter by a scan of particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra, transverse momentum and rapidity distributions and mean multiplicities of π ^± , K^± , p and p̅ produced in the 20

The T2K experiment presents new measurements of neutrino oscillation parameters using 19.7(16.3)× 10^20 protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the previous analysis, an additional 4.7× 10^20 POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on sin ^2θ _13 and the impact of priors on the δ _CP measurement. Both analyses prefer the normal mass ordering and upper octant of sin ^2θ _23 with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on sin ^2θ _13 from reactors, sin ^2θ _23=0.561^+0.021_-0.032 using Feldman–Cousins corrected intervals, and m^2_32=2.494_-0.058^+0.041× 10^-3 eV^2 using constant χ ^2 intervals. The CP-violating phase is constrained to δ _CP=-1.97_-0.70^+0.97 using Feldman–Cousins corrected intervals, and δ _CP=0,π is excluded at more than 90 2σ credible level using a flat prior in δ _CP, and just below 2σ using a flat prior in sinδ _CP. When the external constraint on sin ^2θ _13 is removed, sin ^2θ _13=28.0^+2.8_-6.5× 10^-3, in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses.

Neutron production in antineutrino interactions can lead to bias in energy reconstruction in neutrino oscillation experiments, but these interactions have rarely been studied. MINERvA previously studied neutron production at an average antineutrino energy of ~3 GeV in 2016 and found deficiencies in leading models. In this paper, the MINERvA 6 GeV average antineutrino energy data set is shown to have similar disagreements. A measurement of the cross section for an antineutrino to produce two or more neutrons and have low visible energy is presented as an experiment-independent way to explore neutron production modeling. This cross section disagrees with several leading models' predictions. Neutron modeling techniques from nuclear physics are used to quantify neutron detection uncertainties on this result.

This Letter presents the first simultaneous measurement of the quasielasticlike neutrino-nucleus cross sections on C, water, Fe, Pb, and scintillator (hydrocarbon or CH) as a function of longitudinal and transverse muon momentum. The ratio of cross sections per nucleon between Pb and CH is always above unity and has a characteristic shape as a function of transverse muon momentum that evolves slowly as a function of longitudinal muon momentum. The ratio is constant versus longitudinal momentum within uncertainties above a longitudinal momentum of 4.5  GeV/c. The cross section ratios to CH for C, water, and Fe remain roughly constant with increasing longitudinal momentum, and the ratios between water or C to CH do not have any significant deviation from unity. Both the overall cross section level and the shape for Pb and Fe as a function of transverse muon momentum are not reproduced by current neutrino event generators. These measurements provide a direct test of nuclear effects in quasielasticlike interactions, which are major contributors to long-baseline neutrino oscillation data samples.