NP-HEP synergies for neutrino experiments Kendall Mahn Michigan State University
Disclaimers The following is my personal view. I attempt to summarize major developments on the experimental program + discussions this last November at JLab and MSU. 2
Current: US-funded program is broad. Atmospheric: Super- Kamiokande Neutrino oscillation, exotica (e.g. sterile neutrino, dark matter searches), proton Accelerator: T2K, NOvA, decay Short-Baseline Neutrino Program (SBN) Signal (or background) processes are Future: 0.1-20 GeV charged current (CC) or neutral current (NC) neutrino or antineutrino interactions for atmospheric Accelerator/Atmospheric: and accelerator based programs Deep Underground Neutrino Experiment 3
Current: US-funded program is broad. Atmospheric: Super- Kamiokande Neutrino oscillation, exotica (e.g. sterile Apologies, US centric talk neutrino, dark matter searches), proton Accelerator: T2K, NOvA, decay Short-Baseline Neutrino Examples follow with 3 flavor oscillation program, Program (SBN) but, important to keep highlighting full program capabilities - P. Machado’s talk Signal (or background) processes are Future: 0.1-20 GeV charged current (CC) or neutral current (NC) neutrino or antineutrino interactions for atmospheric Accelerator/Atmospheric: and accelerator based programs Deep Underground Neutrino Experiment 4
Neutrino oscillation open questions Oscillation depends on: • Amplitude determined by mixing Is sin 2 ( θ 23 )=0.5? (maximal angles: θ 12, θ 23 , θ 13 mixing?) • Frequency determined by mass What is the ordering of the splittings: | Δ m 232/31 |, Δ m 221 masses ( Δ m 232/31 > 0? ) • CP violating phase (CPV) Is there CPV in neutrinos? 5
Neutrino oscillation open questions Oscillation depends on: • Amplitude determined by mixing Is sin 2 ( θ 23 )=0.5? (maximal angles: θ 12, θ 23 , θ 13 mixing?) • Frequency determined by mass What is the ordering of the splittings: | Δ m 232/31 |, Δ m 221 masses ( Δ m 232/31 > 0? ) • CP violating phase (CPV) Is there CPV in neutrinos? N α → β X � α ( E true ) × � i F D ( E reco ) = β ( E true ) × P αβ ( E true ) × ✏ β ( E true ) × R i ( E true ; E reco ) i Event rate used to infer oscillation physics 6
Oscillation analysis depends on interaction model Cross section (true kinematics) Need all contributing pro relevant target material, and ~exclusive final states Efficiency (true kinematics) Relationship between true and reconstructed kinematics) N α → β X � α ( E true ) × � i F D ( E reco ) = β ( E true ) × P αβ ( E true ) × ✏ β ( E true ) × R i ( E true ; E reco ) i 7
Can’t isolate single processes: “wide beams” 2 σ ( E ν ) /E ν (10 38 cm 2 nucleon − 1 GeV − 1 ) NEUT 5.3.6, σ ν µ ch ( E ν ) FHC ν µ Flux (arbitrary norm.) CC-Total T2K: ND o ff -axis CC-RES [1707.01048] B.F. Super-K oscillated CC-1p1h+2p2h 1.5 NC-Total NC-RES 1 0.5 0 0 1 2 3 4 5 E ν (GeV) Incident energy is not known. Spread of beam is larger than nuclear effects. 8
2 σ ( E ν ) /E ν (10 38 cm 2 nucleon − 1 GeV − 1 ) NEUT 5.3.6, σ ν µ ch ( E ν ) FHC ν µ Flux (arbitrary norm.) CC-Total T2K: ND o ff -axis CC-RES [1707.01048] B.F. Super-K oscillated CC-1p1h+2p2h 1.5 NC-Total NC-RES Requirement for model: 1 Correct energy dependance for all relevant processes 0.5 0 0 1 2 3 4 5 E ν (GeV) N α → β X � α ( E true ) × � i F D ( E reco ) = β ( E true ) × P αβ ( E true ) × ✏ β ( E true ) × R i ( E true ; E reco ) i 9
1 σ ( E ν ) /E ν (10 38 cm 2 nucleon − 1 GeV − 1 ) ν µ ch ( E ν ) RHC ¯ ν µ Flux (arbitrary norm.) NEUT 5.3.6, σ ¯ CC-Total T2K: ND o ff -axis CC-N π +DIS [1707.01048] B.F. 0.8 Super-K oscillated CC-RES CC-1p1h+2p2h 0.6 Requirement for model: All neutrino flavors! for relevant 0.4 processes 0.2 0 0 1 2 3 4 5 E ν (GeV) N α → β X � α ( E true ) × � i F D ( E reco ) = β ( E true ) × P αβ ( E true ) × ✏ β ( E true ) × R i ( E true ; E reco ) i 10
Need: hadronic state description • T2K event display FGD1 μ- • CC0 π “topology”: 1 muon, no pion ν μ • Includes CCQE, 2p2h, CC1 π (pion absorbed in TPC2 nucleus) 11
Needs: semi to exclusive final states • T2K event display FGD1 μ- • CC0 π “topology”: 1 muon, no pion ν μ • Includes CCQE, 2p2h, CC1 π (pion absorbed in TPC2 nucleus) Requirement for model: All visible particles for efficiency - (background) and energy estimates N α → β X � α ( E true ) × � i F D ( E reco ) = β ( E true ) × P αβ ( E true ) × ✏ β ( E true ) × R i ( E true ; E reco ) i 12
Needs: target material Pb! Target materials: FGD1 • T2K: H2O μ- C8 • NOvA: CH+Cl Ar gas ν μ H8 • SBN, DUNE: Ar TPC2 Requirement for model: Most nuclear targets, esp C, O, Ar - 13
Needs: Energy estimation • Oscillation depends on energy • Estimate from hadronic and/or leptonic information p − m � 2 = m 2 n − m 2 µ + 2 m � n E µ X E QE E ν = E µ + E hadronic ν 2( m � n − E µ + p µ cos θ µ ) muon Neutrino hadronic NOvA T2K SBN NOvA Super-Kamiokande DUNE
Needs: Energy estimation • Nuclear effects bias true and estimated neutrino energy p − m � 2 = m 2 n − m 2 µ + 2 m � n E µ E QE ν 2( m � n − E µ + p µ cos θ µ ) T2K, PRL 112, 181801 (2014) Arbitrary Units CCQE Requirement for model: Nieves multinucleon ( × 5) Correct mix of - pionless ∆ -decay ( × 5) processes per topology true - reconstructed - kinematic relationship -1 -0.5 0 0.5 QE E - E (GeV) reco true N α → β X � α ( E true ) × � i F D ( E reco ) = β ( E true ) × P αβ ( E true ) × ✏ β ( E true ) × R i ( E true ; E reco ) i
Experimental solutions N α → β X � α ( E true ) × � i F D ( E reco ) = β ( E true ) × P αβ ( E true ) × ✏ β ( E true ) × R i ( E true ; E reco ) i X � α ( E true ) × � i ND E reco ) = α ( E true ) × ✏ α ( E true ) × R i ( E true ; E reco ) N α i • Near detector information provide stability monitoring, improved event rate prediction and reduces shared systematic uncertainty from flux, interaction model • Example ND sample: nu-e scattering (low rate, but well known cross section, direct constraint of flux) • Example in-situ information: beam line monitors • External experiments: • Example: electron scattering experiments 16
Experimental solutions N α → β X � α ( E true ) × � i F D ( E reco ) = β ( E true ) × P αβ ( E true ) × ✏ β ( E true ) × R i ( E true ; E reco ) i X � α ( E true ) × � i ND E reco ) = α ( E true ) × ✏ α ( E true ) × R i ( E true ; E reco ) N α i • Near detector information provide stability monitoring, improved event rate prediction and reduces shared systematic uncertainty from flux, interaction model • Example ND sample: nu-e scattering (low rate, but well known cross section, direct constraint of flux) • Example in-situ information: beam line monitors • External experiments: • Example: electron scattering experiments 17
One new approach: ν PRISM Precision Reaction Independant Spectrum Measurement Neutrino energy spectrum changes in transverse direction to (proton) beam 18
One new approach: ν PRISM Precision Reaction Independant Spectrum Measurement DUNE Preliminary Peak shifts down, spectrum narrows 19
One new approach: ν PRISM Precision Reaction Independant Spectrum Measurement DUNE Preliminary N α → β X � α ( E true ) × � i F D ( E reco ) = β ( E true ) × P αβ ( E true ) × ✏ β ( E true ) × R i ( E true ; E reco ) i Many near detectors can approximate far detector oscillated flux! Changing beam line optics can help, too. 20
Persistent challenges: we need theory • Robust implementation • Simulations are using inclusive calculations (quasielastic plus 2p2h plus pion production) with a fragmentation model, plus an FSI cascade or transport. • Example: Disagreements in semi-inclusive data • OK, so this model doesn’t agree … well none of them do! • We need real semi-inclusive MINERvA, PRL 121, theory for the hadronic state 022504 (2018) (NOvA, SBN DUNE … and T2K’s neutron tagging … ) • We need to question simplifications/approximations/ extrapolations 21
Persistent challenges: we need theory • Robust implementation • Processes with small rates at near detectors • Limited near detector information • NC single photon production, NC diffractive production • Electron (anti)neutrinos cross sections • Related: Radiative corrections to exclusive processes on nuclei 22
Persistent challenges: we need theory • Robust implementation • Processes with small rates at near detectors • Transition region // Shallow Inelastic // Deep Inelastic Scattering • Little/no single nucleon data to start from • How do we handle double counting? Extrapolations/approximations? 6 10 × Rate = Events/Year DUNE Opt. 3-horn, 1.1E21 POT/yr, GENIE 2.12.10, CC ν Ar40 µ 0.5 Total QE = 4.4e+06 ev/yr 0.4 MEC = 1.95e+06 ev/yr RES = 5.91e+06 ev/yr 0.3 DIS = 7.39e+06 ev/yr 0.2 0.1 0 0.5 1 1.5 2 2.5 3 3.5 W (GeV/ c 2 ) Rest 23
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