Neutrino Interactions in the GeV Regime Xianguo LU/ University of - PowerPoint PPT Presentation

Neutrino Interactions in the GeV Regime Xianguo LU/ 卢显国 University of Oxford Particle Physics Seminar University of Birmingham Birmingham, 13 March 2019 By NASA/Chris Hadfield

Neutrino Interactions in the GeV Regime Outline ● Neutrino Oscillations – An identity-changing game – Underlying math – Seeing is believing ● Oscillation Measurements – Accelerator-based neutrino experiments – #measured ν / #produced ν – Beam flux, ν and ν interactions – ν and ν interactions – Impact of ν and ν interactions ● Interaction Measurements – MINERvA – Inclusive 'low-recoil' analysis – Inclusive to exclusive ● Exclusive Measurements – Why particle spectra won't work ● Transverse Kinematic Imbalance (TKI) – Principle – Analysis – Future experiments – The very idea – Initial-state kinematics – Neutron initial-state kinematics – Proton initial-state kinematics ● Neutrino-Hydrogen Interactions – Review – The very idea – Perspective 2 Xianguo Lu, Oxford

Physics Beyond Standard Model via Neutrino Oscillations Massless Cartoon by Marco Del Tutto Neutrinos have mass 3 Xianguo Lu, Oxford

Neutrino Oscillations – An identity-changing game v α Superbat v µ v β https://www.lego.com 4 Xianguo Lu, Oxford

Neutrino Oscillations – An identity-changing game v α v α Superbat Anti-superbat v µ v β v β https://www.lego.com 5 Xianguo Lu, Oxford

Neutrino Oscillations – An identity-changing game v α v α P( v α ) + P( v β ) = 1 P( v α ) + P( v β ) = 1 v µ v β v β oscillation between flavor states as a function of time ~distance/energy Only 2 flavors, same oscillation behavior 6 Xianguo Lu, Oxford

Neutrino Oscillations – An identity-changing game *3-flavor paradigm v τ v τ P( v e ) + P( v µ ) + P( v τ ) = 1 P( v e ) + P( v µ ) + P( v τ ) = 1 v µ v µ v µ v µ oscillation between flavor states as a function of time ~distance/energy v e v e 7 Xianguo Lu, Oxford

Neutrino Oscillations – An identity-changing game v τ v τ Super-flashy-bat Anti-super-flashat v µ v µ v µ v µ v e v e 8 Xianguo Lu, Oxford https://www.lego.com

Neutrino Oscillations – An identity-changing game v τ v τ Super-flashy-bat Anti-super-flashat v µ v µ v µ v µ v e v e Oscillation property difference → CP-Symmetry violation (CP violation) 9 Xianguo Lu, Oxford

Neutrino Oscillations – Underlying math Neutrino oscillations depend on mixing parameters and mass differences. Pontecorvo–Maki–Nakagawa–Sakata PMNS matrix ● What is the absolute neutrino mass? ● Why is this mass so small? ● How is the different mass ordered? ● Are there more than 3 types of neutrino? 10 Xianguo Lu, Oxford

Neutrino Oscillations – Underlying math Neutrino oscillations depend on mixing parameters and mass differences. PMNS matrix θ 13 ≠ 0 → δ CP can be observed 11 Xianguo Lu, Oxford

Neutrino Oscillations – Underlying math Neutrino oscillations depend on mixing parameters and mass differences. PMNS matrix PMNS matrix θ 13 ≠ 0 → δ CP can be observed With a ν µ beam CP-odd term 12 Xianguo Lu, Oxford * neglecting matter effects

Neutrino Oscillations – Underlying math Neutrino oscillations depend on mixing parameters and mass differences. PMNS matrix PMNS matrix θ 13 ≠ 0 → δ CP can be observed With a ν µ beam flip sign by CPT symmetry δ CP →CP violation 13 Xianguo Lu, Oxford * neglecting matter effects

Neutrino Oscillations – Seeing is believing – Charge–Parity symmetry Violation (CPV)? Matter Antimatter 14 Xianguo Lu, Oxford

Neutrino Oscillations – Seeing is believing – Charge–Parity symmetry Violation (CPV)? ν µ → ν e ν µ → ν e == CPV 15 Xianguo Lu, Oxford

Neutrino Oscillations – Seeing is believing Time trajectory in probability space No CPV CPV http://www-pnp.physics.ox.ac.uk/~luxi/transport/visual/visos/vacuumnumuantinumu_cpoff.mov http://www-pnp.physics.ox.ac.uk/~luxi/transport/visual/visos/vacuumnumuantinumu_cpon.mov 16 Xianguo Lu, Oxford

Oscillation Measurements – Accelerator-based neutrino experiments https://lbnf.fnal.gov/beam.html By Inductiveload Nuclear β decay ν beam: “ β decay” of highly boosted collision products MeV regime GeV regime * also the cross section is larger at GeV 17 Xianguo Lu, Oxford

Oscillation Measurements – Accelerator-based neutrino experiments T2K ν and ν beams DUNE (from 2026) 18 Xianguo Lu, Oxford

Oscillation Measurements – #measured ν / #produced ν T2K # measured ν and ν : energy, event count # produced ν and ν : beam flux, interaction rate DUNE (from 2026) 19 Xianguo Lu, Oxford

Oscillation Measurements – Beam flux, ν and ν interactions T2K Near Detectors @280m DUNE (from 2026) 20 Xianguo Lu, Oxford

Oscillation Measurements – Beam flux, ν and ν interactions T2K ● Now@ T2K : [flux (9%) + interaction (15%)] → 8% after Near Detector constraint Near Detectors ● Target CP violation sensitivity requires total sys. uncertainty < 1-2% @280m ● Neutrino interactions, if not understood, would be fatal DUNE (from 2026) 21 Xianguo Lu, Oxford

Oscillation Measurements – ν and ν interactions Cartoon by Marco Del Tutto - + proton neutron neutrino antineutrino Intrinsic difference in ν and ν event rates without CPV 22 Xianguo Lu, Oxford

Oscillation Measurements – ν and ν interactions Cartoon by Marco Del Tutto + proton neutron proton neutron neutrino antineutrino Nuclear effects like “2p2h” make it worse Nuclear effects : all effects due to target A>1 Proton and neutron have VERY different experimental signatures 23 Xianguo Lu, Oxford

Oscillation Measurements – ν and ν interactions higher event rates more complicated interactions DUNE Ar T2K O Far Detector (H 2 O) C T2K Near Detector (CH) He H Simplest interaction 24 Xianguo Lu, Oxford

Oscillation Measurements – Impact of ν and ν interactions Coloma, Huber, Phys.Rev.Lett. 111 (2013), 221802 Difference in mass states Mock measurement with perfect knowledge of interactions Mixing between µ and τ flavors 25 Xianguo Lu, Oxford arXiv:1801.09643

Oscillation Measurements – Impact of ν and ν interactions Coloma, Huber, Phys.Rev.Lett. 111 (2013), 221802 Difference in mass states Mock measurement ignoring nuclear effects of interactions Mixing between µ and τ flavors 26 Xianguo Lu, Oxford arXiv:1801.09643

Interaction Measurements – MINERvA Only dedicated experiment for ν and ν interactions currently running Various targets: He, CH, O, Fe, Pb 27

Interaction Measurements – MINERvA Nucl.Instrum.Meth. 676 (2012) 44-49, Nucl.Instrum.Meth. A743 (2014) 130-159 Scintillator tracker: Hydrocarbon (CH) target Homogeneous non-magnetized active tracker 28 Xianguo Lu, Oxford

Interaction Measurements – MINERvA Energy 29 Xianguo Lu, Oxford

Formaggio, Zeller, Rev.Mod.Phys. 84 (2012) 1307-1341 NuMI low energy beam <E ν > ~ 3 GeV L. Fields 30 Xianguo Lu, Oxford

Homogeneous non-magnetized active tracker → same as LAr detector What do we do with such great detail in final states? 31 Xianguo Lu, Oxford

Interaction Measurements – Inclusive 'low-recoil' analysis ν / ν beam µ Scintillator Active Tracker Nucl.Instrum.Meth. 676 (2012) 44-49, Nucl.Instrum.Meth. A743 (2014) 130-159 32 Xianguo Lu, Oxford

Interaction Measurements – Inclusive 'low-recoil' analysis Nucl.Instrum.Meth. 676 (2012) 44-49, Nucl.Instrum.Meth. A743 (2014) 130-159 ~ single proton kinetic energy spectrum in QE ~ π (+p) kinetic energy spectrum in RES 33 Xianguo Lu, Oxford

Base Model (GENIE + pion reweight + RPA + 2p2h) [MINERvA, Phys.Rev.Lett. 116 (2016) 071802] [MINERvA, Phys.Rev.Lett. 120 (2018) 221805] ν ν 34 Xianguo Lu, Oxford

Base Model + Neutrino Tune = MnvGENIE-v1 [MINERvA, Phys.Rev.Lett. 116 (2016) 071802] ν fit Tune is fit to neutrino data only ● Neutrino tune Tuned 2p2h = (1+G)·Valencia 2p2h, G: 2D Gaussian(q0, q3) determined in fit to neutrino data ● Empirical modification to 2p2h 35 Xianguo Lu, Oxford

Base Model + Neutrino Tune = MnvGENIE-v1 [MINERvA, Phys.Rev.Lett. 116 (2016) 071802] [MINERvA, Phys.Rev.Lett. 120 (2018) 221805] ν ν Prediction fit Tuned model predicts ν data well Tune is fit to neutrino data only ● Apply neutrino tune directly to anti-neutrino Tuned 2p2h = (1+G)·Valencia 2p2h, G: 2D Gaussian(q0, q3) determined in fit to neutrino data ● Empirical modification to 2p2h 36 Xianguo Lu, Oxford

Interaction Measurements – Inclusive to exclusive ν inclusive measurements ν quasi-elastic-like interactions Not to cover in this talk µ – ν inclusive measurements Proton below → 2p2h tune tracking threshold [MINERvA, Phys.Rev. D99, 012004 (2019)] ν quasi-elastic-like interactions Proton above tracking threshold [MINERvA, Phys.Rev.Lett. 121, 022504 (2018)] 37 Xianguo Lu, Oxford

Exclusive Measurements – Why particle spectra won't work Problematic “lasagna” region: 2p2h Resonance production with pion absorped in nucleus Proton gain & lose energy in nucleus True quasi-elastic Why can't we tell what is wrong? ➢ Without nuclear effects, spectra still depend on ● flux MINERvA ● nucleon -level physics PRL, 121, 022504 (2018) Proton polar angle (degree) 38 Xianguo Lu, Oxford