Precision neutrino interaction measurements with the nuSCOPE experiment

Precision neutrino interaction measurements Precision neutrino interaction measurements with the nuSCOPE experiment with the nuSCOPE experiment F. Bramati on behalf of the F. Bramati on behalf of the nuSCOPE nuSCOPE Collaboration Collaboration 1 XXI Workshop on Neutrino Telescopes XXI Workshop on Neutrino Telescopes Padova Padova, 29 Sept – 3 Oct 2025 , 29 Sept – 3 Oct 2025 •The portal to test CP violation and mass hierarchy : high precision measurements of νμ →νe appearance and νμ →νμ disappearance probabilities, and corresponding for anti-neutrinos. ➢precise knowledge of νe and νμ cross sections is required ! Neutrino cross sections … still poorly known ! •The νe and νμ cross sections are known at O(10 – 30%) level in the few GeV energy range : →their precision is limited by systematic uncertainties. current →measurements can be hard to interpret due to broad-band beams. •The next generation of long-baseline experiments (DUNE, HyperK) aims at high precision ν oscillation measurements : test the 3 ν families paradigm determination of the ν mass ordering test CP asymmetry in the lepton sector •Moreover, precise measurements of ν cross-sections are essential to improve theoretical knowledge of ν - nuclei interactions ... and can provide valuable insights for nuclear physics. 2 •The leading source of systematics on cross-section measurements is the neutrino flux, generally known with a precision worse than O(5-10%) ... •Moreover, the initial-state neutrino energy is not known on an event-by-event basis ... nuSCOPE: a monitored and tagged neutrino beam 3 •nuSCOPE is a non-conventional neutrino beam that combines a monitored and tagged neutrino beam ! →high-precision neutrino cross-section measurements with %-level flux systematics and neutrino energy measurement on an event-by-event basis. •The nuSCOPE reference document has been posted on arXiv:2503.21589, as an input document submitted to ESPP 2026 Update. Instrumented static focusing system Two quadrupole triplet, four dipoles, six silicon trackers for momentum measurement and tagging Instrumented decay tunnel longitudinally segmented calorimeter modules for charged lepton monitoring •Slow extraction mode (1013 PoT / 9.6s) to reduce instantaneous rate (mitigated by proximity and large size of neutrino detector!). •Narrow-band beamline: secondary mesons K+ / π+ selected with p = 8.5 GeV/c ± 10%. Instrumented dump Muon spectrometer and muon range-meter see next slides for possible locations at CERN, with proton sharing at SPS compatible with BDF/SHiP Proton accelerator : CERN SPS (400 GeV/c) graphite target nuSCOPE : improved neutrino flux knowledge with charged lepton monitoring •Monitored neutrino beams are a novel technology aimed at measure the flux and flavour of neutrinos produced at the source at percent level. A. Longhin, L. Ludovici, F. Terranova Eur.Phys.J.C 75 (2015) 155 Conventional beamline with instrumented decay tunnel for the identification of charged leptons measuring charged lepton rate ⇔ monitoring ν flux •Monitoring: effective removal of systematic uncertainties associated with neutrino flux modelling. •The NP06/ENUBET experiment, to date, is the most advanced implementation of a monitored neutrino beam. –measure positrons from Ke3 (K+ e→+ π0 νe) decay by means of the instrumented decay tunnel ⇒ νe flux measurement –measure muons from Kμν (K+ μ→+ νμ) with the instrumented decay tunnel and from πμν (π+ μ→+ νμ) instrumenting the hadron dump as a range meter ⇒ νμ flux measurement 4 The NP06/ENUBET prototype of a section of the decay tunnel (1.65m length, 90° azimuthal coverage) tested at CERN PS T9. Eur. Phys. J. C (2023) 83: 964 0 2 4 6 8 [GeV] ν E 0 0.5 1 1.5 2 ) / E [%] ν (Eσ per tracking plane 0 0.5% X per tracking plane 0 1% X nuSCOPE : neutrino energy measurement using neutrino tagging •In addition to a monitored neutrino beam, a tagged neutrino beam uniquely associate the neutrino with its accompanying particles in the beamline. •The use of state-of-the-art silicon trackers is the core of the tagged neutrino beam proposed by NuTag: •beam and muon spectrometers are installed along the beamline to track π, K and μ. •kinematic reconstruction of neutrinos produced in π+ μ→+ νμ and K+ μ→+ νμ decays. •each νμ interaction observed in the neutrino detector is uniquely associated to its parent meson and associated muon. •NA62 reported a first tagged neutrino candidate from K+ μ→+ νμ decay (Phys. Lett. B 863 (2025) 139345). NA62-GTK 5 π+, K+ μ+ νμ pν = pπ,K - pμ •The beam spectrometer technology is the main challenge for tagging : –high particle rate to cope with : 20 MHz/mm2 at the center of the first beam spectrometer, 0.6 MHz/mm2 at the muon spectrometer (9.6 s spills of 1013 PoTs). –4D track reconstruction (space + time) •State-of-the-art : NA62 beam tracker (GTK) •New silicon technologies are developed in synergy with HL-LHC (LHCb-VELO upgrade) : –TimeSPOT, IGNITE at INFN, LA-PICOPIX at CERN JINST 14 P07010 see Mathieu Perrin-Terrin’s plenary talk The reference neutrino detector setup 6 •Current preliminary studies performed assuming a simplistic detector design : –fiducial mass 500 ton LAr / 100 ton of water (could be WC or WbLS) –4 x 4 m2 front-face area –located at a distance of 25 m from the tunnel exit We will host an open workshop @ CERN during 13-15 October to discuss the detector design https://indico.cern.ch/event/1548855/ 500 ton of LAr 100 ton of water •The total pot statistic is 1.4 · 1019 pot, to be collected in ~ 5 years. →proton sharing at SPS compatible with BDF/ShiP ! •Projected event rates estimated with GENIE AR23_20i_00_000 model. •Low beam intensity compensated by large detector size and proximity to beam : –O( 1.0 x 106 ) / O( 1.2 x 104 ) monitored νμ / νe CC events in both LAr and water –Tagging performance : ●7.6 x 105 tagged νμ CC events in LAr (500 ton) ●1.4 x 105 tagged νμ CC events in water (100 ton) –Of which 52k tagged νμ CC0π events 0 5000 10000 15000 20000 25000 30000 35000 events / 1.4 1019 pot / 0.1 GeV tagged event rate total 7.632 105 CCQE 1.975 105 25.88 % 2p2h 0.683 105 8.95 % RES 2.547 105 33.37 % other 2.427 105 31.8 % 0246810 Etrue [GeV] 0 5 error [%] tagging efficiency ~ 80% for πμν 500 ton LAr CC Inc. 22.3 m / 6.3 m 1 10 2 10 3 10 4 10 pot 19 10⋅ event rate / 1.4 µ ν 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 r [m] 0 1 2 3 4 5 6 7 8 9 10 [GeV] ν E pot 19 10⋅ event rate / 1.4 µ ν The narrow-band off-axis technique precise determination of Eν : w/o relying on reconstruction of final state particles from νμ interactions select νμ with given energy with a radial cut 7 π+, K+ νμ μ+ •νμ interacting at different off-axis angles span different energy ranges. •selecting a radial slice, a flux narrower than the total flux can be probed. •10 radial slices, each spanning a 20 cm window. –access to different energy spectra probing many off-axis angles (0 - 4.5°) Narrow-band off-axis technique narrow momentum beam O(10%) ￬ (Eν, r) are strongly correlated ●Eν = neutrino energy ●r = radial distance of interaction vertex from beam axis inspired by DUNE-PRISM, SBND-PRISM and IWCD … we can also use PRISM to create a virtual νμ flux matching the shape of a target νe flux using linear combinations of νμ off-axis real fluxes → access to σ(νe) / σ(νμ) ratio (see backup) νμ event rate monitored neutrino beam 0246810 E [GeV] 0 10000 20000 30000 40000 events / 1.4 1019 pot / 0.1 GeV narrow band off-axis event rate 4 6 8 10 0 500 1000 1500 event rate total event rate monitored event rate HK DUNE 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 off-axis radial position [m] The narrow-band off-axis technique precise determination of Eν : w/o relying on reconstruction of final state particles from νμ interactions 8 π+, K+ νμ μ+ •νμ interacting at different off-axis angles span different energy ranges. •selecting a radial slice, a flux narrower than the total flux can be probed. •10 radial slices, each spanning a 20 cm window. –access to different energy spectra probing many off-axis angles (0 - 4.5°) Narrow-band off-axis technique narrow momentum beam O(10%) ￬ (Eν, r) are strongly correlated ●Eν = neutrino energy ●r = radial distance of interaction vertex from beam axis inspired by DUNE-PRISM, SBND-PRISM and IWCD πμν-like Kμν-like 500 ton LAr CC Inc. monitored neutrino beam 0 1 2 3 4 5 6 7 8 [10 38cm2/nucleon] -like K -like × 10 AR23_20i_00_000 G21_11a_00_000 monitored sample , -like flux, 1.4 1019 pot monitored sample , K -like flux, 1.4 1019 pot DUNE flux 2 4 6 8 10 E [GeV] 0 1 2 error [%] stat stat + syst 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 off-axis radial position [m] flux averaged νμ CC inclusive cross section measurement horizontal error bars encase the flux width (68% percentiles wrt mean energy) 9 π+, K+ νμ μ+ •The narrow band off-axis technique can provide an “a priori” measurement of neutrino energy for νμ w/o relying on reconstruction of final-state particles. projected CC inclusive νμ cross section measurement •The πμνand Kμν-like peaks in the narrow band off-axis fluxes can be separated using an energy cut at ~ 4 GeV. •Since πμν and Kμν peaks are well separated, flux averaged neutrino cross section can be measured using both peaks. 0246810 E [GeV] 0 10000 20000 30000 40000 events / 1.4 1019 pot / 0.1 GeV narrow band off-axis event rate 4 6 8 10 0 500 1000 1500 event rate total event rate monitored event rate HK DUNE 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 off-axis radial position [m] 500 ton LAr CC Inc. monitored neutrino beam Backup Backup 16 Meson and muon tracking 17 ●Parent and muon tracking requires a time resolution of O(100 ps) and a detector granularity of 300 μm. ●Particle rates in the hottest (central) planes are 20 MHz/mm2 for 1013 pot in 9.6 s. The peak fluence (non-ionizing dose) is 1016 MeV neq /cm2. ●We thus benefit from the technology currently being developed for the LHCb velo upgrade and pioneered at the 2 MHz/mm2 level by NA62. •Silicon detectors are needed only at the core of the tracking planes. •Scintillating fiber planes are sufficient to instrument the outer radii. 1013 POT / 9.6 s 1013 POT / 9.6 s 12 x 10 cm220 x 16 cm280 x 100 cm2 nuSCOPE implementation at the CERN accelerator complex 18 ●The implementation of the facility in the CERN complex is currently being studied in the framework of the CERN Physics Beyond Collider (PBC) program. The most promising locations are in a new experimental Hall (ECN4) in the Prevessin campus and in an extension of existing tunnels near the SPS Long Straight Section 6 (LSS6), close to HighRadMat in the Meyrin Campus. Some of the work affecting the LHC injector needs to be done in a Long Shutdown. 19 F. Terranova seminar at Imperial College London, UK, 30 May 2025 Implementation at CERN : pros and cons 20 •ECN4 (North Area, Prevessin) : –A dedicated experimental hall provides greater flexibility for detector installation and the addition of new detectors for cross-section studies with specific targets. –Slow extraction is already implemented in LSS2. –The beam splitter presents significant technical challenges. –Neutrino detectors have minimal overburden, leading to increased cosmic ray background during long extractions. –May require a dedicated cycle for nuSCOPE, potentially increasing the impact on proton availability for other experiments. •TNC/TT61/TCC6 (East Area, Meyrin) – currently our favorite option : –Detectors are located underground. –Minimal interference with proton sharing among fixed target experiments. –Requires enlargement of existing tunnels to accommodate neutrino detectors. –Implementation of a non-local slow extraction is needed, similar to the system used at the PS. In both cases, nuSCOPE requires <25% of the TCC2 intensity and, hence is compatible with the CERN fixed target programme in 2030 - 40 flux averaged νμ CC0π double differential cross section 21 •The simplest channel to measure is CCQE : a single lepton and nucleon in the final state. •The closest visible final state is CC0π topology : a single lepton and no pions in the final state. –contributions from CCQE, multi-nucleon interactions (2p2h), resonant pion production with pion absorption (RES), other process with no pions in the final state. same interaction topologies from different interactions due to final state interactions (FSI) taking place inside the nucleus •double differential νμ cross sections as a function of outgoing lepton kinematics pμ , cosθμ : –lepton kinematics maps to the momentum q3 and energy transfer ω = q0 in neutrino scattering, averaged over the range of available neutrino energies. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 d2 dp dcos 10 38 cm2 nucleon GeV/c 0.98 cos < 1.0 G21_11a_00_000 AR23_20i_00_000 CCQE 2p2h RES other 0246810 p [GeV/c] 0 5 error [%] 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 d2 dp dcos 10 38 cm2 nucleon GeV/c 0.94 cos < 0.98 G21_11a_00_000 AR23_20i_00_000 CCQE 2p2h RES other 0246810 p [GeV/c] 0 5 error [%] •few %-level statistical uncertainty •w/o a monitored beam measurements become systematically limited •statistical power of projected measurement enables to discriminate between different models •different kinematic regions are sensitive to different aspects of modeling differences 500 ton LAr CC Inc. 500 ton LAr CC Inc. flux averaged νe inclusive double differential cross section 22 •double differential νe cross sections as a function of calorimetric observables Eavail , q3 : •The available (recoil) energy Eavail is the calorimetric sum of the outgoing hadronic state : –it is a proxy for the energy seen in a detector with a high tracking threshold, where individual charged-pions are not identified, and no neutron energy is measured. •q3 is the projection of the momentum transfer q onto the incoming neutrino direction : –assuming that reconstructed q3 from particle kinematics has been unfolded to its true value. –it is a model-dependent procedure, but the model dependence could be mitigated with tagging. 0.000 0.025 0.050 0.075 0.100 0.125 0.150 0.175 d2 dEavaildqtrue 3 10 38 cm2 nucleon GeV2/c 1 qtrue 3 < 2 GeV/c G21_11a_00_000 AR23_20i_00_000 CCQE 2p2h RES other 012345678 Eavail [GeV] 0 5 error [%] 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 d2 dEavaildqtrue 3 10 38 cm2 nucleon GeV2/c 2 qtrue 3 < 3 GeV/c G21_11a_00_000 AR23_20i_00_000 CCQE 2p2h RES other 012345678 Eavail [GeV] 0 5 error [%] 0.000 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 d2 dEavaildqtrue 3 10 38 cm2 nucleon GeV2/c 3 qtrue 3 < 8 GeV/c G21_11a_00_000 AR23_20i_00_000 CCQE 2p2h RES other 012345678 Eavail [GeV] 0 5 error [%] 0246810 E [GeV] 0 1 2 3 4 / cm2 / 1.4 1019 pot 1e9 narrow band off-axis fluxes target e flux × 10 DUNE 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 off-axis radial position [m] PRISM technique using narrow band off-axis fluxes : νe / νμ cross section ratio 23 •differences between νe and νμ cross-sections is an important systematic for the measurement of νμ →νe oscillation : –few direct constraints on νe cross-section exist ... extrapolated from νμ beam at near detector. –assuming lepton universality, differences in νe and νμ cross-sections are due to lepton mass terms, significant at relatively low energy transfers differences in →σ(νe) / σ(νμ) ratio of the order of 3% predicted by nuclear models in these regions. •The PRISM technique is being investigated by HK, SBND and DUNE to create virtual fluxes from linear combinations of off-axis fluxes. •In nuSCOPE, it is possible to create a virtual νμ flux reproducing the shape of a target νe flux using linear combinations of narrow νμ off-axis real fluxes. 0246810 E [GeV] 0.000 0.005 0.010 0.015 0.020 0.025 0.030 / cm2 e target flux e virtual flux we measure the νe flux integrated cross section and compare it with the corresponding νμ cross section built from narrow-width fluxes. → σ(νe) / σ(νμ) ratio measurement at 2% neutrino tagging may further improve it! 0246810 E [GeV] 0 50 100 150 200 250 events / 1.4 1019 pot / 0.1 GeV NC1 0=10.0 % narrow band off-axis event rate: NC 1 0 (inclusive) 4 6 8 10 0 2 4 6 8 NC 1 0 event rate total event rate monitored event rate HK DUNE 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 off-axis radial position [m] 0.00 0.05 0.10 0.15 0.20 0.25 0.30 [10 38cm2/nucleon] -like K -like × 10 NC 1 0 (inclusive) NC1 0=10.0 % AR23_20i_00_000 monitored sample , -like flux, 1.4 1019 pot monitored sample , K -like flux, 1.4 1019 pot DUNE flux 12345678 E [GeV] 0 5 10 15 20 error [%] stat stat + syst 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 off-axis radial position [m] flux averaged νμ NC π0 cross section measurement discrepancies between cross-section curves and measurement points are due to statistical fluctuations due to reduced statistics of this topology 24 •NC interactions constitute a source of background for neutrino oscillation : –production of neutral pions in NC interactions, i.e. NC π0 topology, is the main channel contributing to this background. –photons can be mis-reconstructed as electrons →NC events are mis-attributed to CC events with a final state electron. •This process was measured by MicroBooNE, see Phys. Rev. D 107, 012004. projected CC inclusive νμ cross section measurement •10% efficiency applied to the total number of NCπ0 •selection of events with 1π0 in the final state and either zero or one proton with momentum above 300 MeV/c. MicroBooNE stat. 6% syst. 16% flux syst. 12% expected stat. error below 10% across the majority of DUNE energies and below 5% in the peak region. neutrino tagging : νμ energy measurement and CC inclusive cross section 25 •In a tagged neutrino beam the neutrino energy is known on an event-by-event basis with sub-% energy resolution. π+, K+ νμ μ+ •Neutrino tagging can be used to directly measure: 1. the νμ cross section σ(Eν) as a function of true Eν 2. the neutrino energy bias calibrate neutrino energy bias of DUNE far detectors 0 10000 20000 30000 40000 50000 60000 70000 events / 1.4 1019 pot / 10 MeV tagged event rate total 7.632 105 CCQE 1.975 105 25.88 % 2p2h 0.683 105 8.95 % RES 2.547 105 33.37 % other 2.427 105 31.8 % -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 Ereco Etrue [GeV] 0 5 error [%] 0 20000 40000 60000 80000 100000 events / 1.4 1019 pot / 10 MeV tagged event rate total 7.632 105 CCQE 1.975 105 25.88 % 2p2h 0.683 105 8.95 % RES 2.547 105 33.37 % other 2.427 105 31.8 % -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 (Ereco Etrue)/Etrue 0 5 error [%] absolute bias relative bias Sources of bias : 1. position →charged pions multiplicity ΔEπ = Nπ · mπ 2. position → nucleon removal energy ΔEnucleons 3. width spread in removal energy→ 4. neutrons missing fraction of → energy carried by neutrons mπ mπ