Neutrinos Induced Pion Production in MINERvA Aaron Higuera Universidad de Guanajuato, Mexico On behalf of the MINERvA collaboration
Outline Neutrinos Induced Pion Production MINERvA Experiment E-938 CC Inclusive Pion Production CC Exclusive Pion Production (Coherent) Summary 2
Neutrinos Induced Pion Production Why measuring π production on nuclei is important? Test of production and final state interaction models Background to oscillation NC 1π 0 background to νe appearance CC 1π + background to CCQE Evidence of Electron Neutrino Appearance in a Muon Neutrino T2K arxiv:1304.0841 MINERvA PRL 111, 022502(2013) Model Parameter Uncertainty CC Resonance Norm. 20% Resonance MA 20% Non-resonances π production 50% 3
Neutrinos Induced Pion Production G. P. Zeller, PDG 2012 Early experiments measured exclusive final states on H and D2 bubble chambers Neutrino hits a nucleon Low statistics Uncertain flux determination 4
Neutrinos Induced Pion Production More recently measurements by MiniBooNE of CC 1π + on CH2 High statistics Neutrino hits a nucleon within a nucleus Final State Interaction FSI S. Dytman NuInt 2012, GIBUU P. Rodrigues NuInt 2012 Theoretical band ANL & BNL inputs Disagreement between MiniBooNE and H, D2 data? Problem with FSI model? Tension between nucleon and nucleus data? 5
MINERvA MINERvA is a neutrino scattering experiment in the NuMI beamline at Fermilab. Designed to measure neutrino cross sections, final states, nuclear effects and A-dependence on a variety of targets in the few-gev region. 6
NuMI Beamline figure courtesy Z. Pavlović 120 GeV/c protons from MI Graphite target Tunable spectrum Neutrino and Anti-Neutrinos 7
MINERvA Data Set (LE run) Physics data set: 3.98x10 20 P.O.T LE Neutrino mode 1.7x10 20 P.O.T LE Anti-Neutrino mode Detector live time > 97.0% 8
MINERvA Data Set (LE run) Today s Results 9
CC Inclusive Pion Production by Neutrinos Signal definition FV tracker CH µ - MINOS-matched track At least 1π ± in the final state 41.7 % efficiency 80.3 % purity 10
CC Inclusive Pion Production by Neutrinos 11
CC Inclusive Pion Production by Neutrinos 12
CC Inclusive Pion Production by Neutrinos 13
CC Coherent Pion Production ν+a µ - +A+π + ν A(Z,n) Two final states particles µ + π + Small Q 2 Nucleus remains in its ground state Small t =(q-pπ) 2 µ - π + PCAC Models The reaction is generally modeled by combining the PCAC with a specific description of the pion-nucleus scattering. Rein-Sehgal, Nuclear Phys B223, 29-44 (1983). Berger-Sehgal, Phys. Rev. D79, 053003 (2009). Paschos-Schalla, Phys. Rev. D80, 033005 (2009). 14
CC Coherent Pion Production ν+a µ - +A+π + ν A(Z,n) µ - Microscopic Models They have neutrino-nucleon pion production via resonance production (typically, resonance). Distortion of the pion wave function is taken into account with a realistic optical potential. Two final states particles µ + π + Small Q 2 Nucleus remains in its ground state Small t =(q-pπ) 2 π + Alvarez-Ruso et al. Phys. Rev. C 75, 055501 (2007). Hernandez, Nieves et al. Phys. Rev. D 76, 033005 (2007). 15
CC Coherent Pion Production ν+a µ - +A+π + ν A(Z,n) Two final states particles µ + π + Small Q 2 Nucleus remains in its ground state Small t =(q-pπ) 2 µ - π + Existing data from bubble chambers Low statistics Recent measurements could not find evidence at very low neutrino energies K2K (Phys. Rev. Lett 95) & SciBooNE (Phys. Rev. D78) Applications NC case is one of the key background for νe appearance Coherent pion production can be used to determine the divergence of neutrino beams 16
CC Coherent Pion Production ν+a µ - +A+π + Signal definition FV tracker CH µ - MINOS-matched track No proton Low Q 2 No vertex energy Low t =(q-pπ) 2 Data ν+a µ + +A+π - Signal definition FV tracker CH µ + MINOS-matched track No vertex energy Low t =(q-pπ) 2 Energy Box strip MINOS-matched track module 17 x view from above
CC Exclusive Pion Production (Coherent) ν+a µ - +A+π + ν+a µ + +A+π - Events / Bin!10 12 10 8 6 4 3 MINER"A Preliminary POT Normalized 9.42e+19 POT Data Pion Proton Other Signal definition FV tracker CH µ + MINOS-matched track No vertex energy Low t =(q-pπ) 2 2 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Proton Range PID Score 18
CC Exclusive Pion Production (Coherent) ν+a µ - +A+π + ν+a µ + +A+π - 2 Events / 0.05 (GeV/c) 1 0.8 0.6 0.4!10 3 MINER"A Preliminary POT Normalized 9.42e+19 POT DATA COH QE RES W<1.4 1.4<W<2.0 2 W>2.0 Q <1.0 DIS Other Signal definition FV tracker CH µ + MINOS-matched track No vertex energy Low t =(q-pπ) 2 0.2 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2 Reconstructed Q 2 (GeV/c) 19
CC Exclusive Pion Production (Coherent) ν+a µ - +A+π + ν+a µ + +A+π - Events / 10 MeV 700 600 500 400 MINER!A Preliminary POT Normalized 9.42e+19 POT DATA COH QE RES W<1.4 1.4<W<2.0 2 W>2.0 Q <1.0 DIS Other Events / 10 MeV!10 1.4 1.2 1 0.8 3 MINER"A Preliminary POT Normalized 1.02e+20 POT DATA COH QE RES W<1.4 1.4<W<2.0 2 W>2.0 Q <1.0 DIS Other 300 0.6 200 0.4 100 0.2 0 0 50 100 150 200 250 300 Energy Box (MeV) 0 0 50 100 150 200 250 300 Energy Box (MeV) 20
CC Exclusive Pion Production (Coherent) ν+a µ - +A+π + ν+a µ + +A+π - 2 Events / 0.025 (GeV/c) 350 300 250 200 150 MINER"A Preliminary POT Normalized 9.42e+19 POT DATA COH QE RES W<1.4 1.4<W<2.0 2 W>2.0 Q <1.0 DIS Other 2 Events / 0.025 (GeV/c) 400 350 300 250 200 150 MINER"A Preliminary POT Normalized 1.02e+20 POT DATA COH QE RES W<1.4 1.4<W<2.0 2 W>2.0 Q <1.0 DIS Other 100 100 50 50 0 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 2 2 Reconstructed t = (q-p ) (GeV/c)! 0 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 2 2 Reconstructed t = (q-p ) (GeV/c)! 21
Summary MINERvA has the capability of studying inclusive, exclusive and coherent pion production by neutrinos and anti-neutrinos MINERvA will provide high statistics results Need to investigate A-dependence of inclusive and exclusive pion production using one single detector First evaluation of systematic errors Δ-rich sub sample could be used to measure resonance form factor parameters Stay tuned for results soon!!! 22
The MINERvA Collaboration Thank you for listening 23
Back-up Slides 24
CC Inclusive Pion Production by Neutrinos Signal definition FV tracker CH µ - MINOS-matched track At least 1π ± in the final state 41.7 % efficiency 80.3 % purity 25
CC Inclusive Pion Production by Neutrinos Signal definition FV tracker CH µ - MINOS-matched track At least 1π ± in the final state 41.7 % efficiency 80.3 % purity 26
CC Inclusive Pion Production by Neutrinos Signal definition FV tracker CH µ - MINOS-matched track At least 1π ± in the final state 41.7 % efficiency 80.3 % purity Q 2 = 2Ev(Eµ-pµcosθµ)-m 2 µ W 2 = m 2 n - Q 2 + 2 m 2 n EH 27
Single π + Production on C12 Cross Section S. Dytman NuInt 2009 28
Coherent Cross Section S. Dytman NuInt 2009 29
CC Coherent Candidate Neutrino Data strip 2019/5/339/1 Ev = 6.53 GeV Q 2 = 0.038 t = 0.001 Eπ = 2.37 GeV x view from above module 30
CC Coherent Candidate Anti-Neutrino Data strip 2667/17/67/13 Ev = 4.38 GeV Q 2 = 0.091 t = 0.01 Eπ = 2.26 GeV x view from above module 31
MINERvA Test Beam Experiment T-977 Copper Target Wire Chambers 1-4 Dipole Magnets ToF Panels 1-2 16 GeV Pion Beam Target (1). Collimator (2). Time of Flight System (3,10). Spectrometer (4,5,6,8,9). Test Beam Detector. Tertiary beam 400-2000 MeV/c 32
Tertiary Beam Component 33
Tertiary Beam Component 34
Current Analysis (Calorimetry) Energy Response / Incoming Energy 0.65 0.6 0.55 0.5 0.45 T977 + MINERvA Preliminary Positive Pions Data with Stat. Errors MC with Syst. Errors 0.6 0.8 1 1.2 1.4 1.6 1.8 Pion Total Energy = Available Energy (GeV) 20 ECal + 20 HCal config. The energy response is corrected for the passive material. 35