Recent results from MINERvA

Transcription

1 Recent results from MINERvA Jonathan Miller for the MINERvA Collaboration Universidad Tecnica Federico Santa Maria 1 PANIC NOW

2 Outline Introduction to MINERvA Recent important results: charged pion production coherent pion production inclusive charged current scattering quasielastic scattering arxiv: and arxiv: Conclusions and Future

3 MINERνA" MINERvA Collaboration More than just a detector " MINERνA" Located underground at Fermilab, ~8"collaborators"from"par?cle"and"nuclear"physics"" near Chicago USA. University of Athens Otterbein University More than just a detector " University of Texas at Austin Pontificia Universidad Catolica del Peru Centro Brasileiro de Pesquisas Físicas University of Pittsburgh Institutions from 9 countries Fermilab University of Rochester University of Florida Rutgers University ~8"collaborators"from"par?cle"and"nuclear"physics"" Université de Genève Tufts University with over 6 collaborators. Universidad de Guanajuato University of California at Irvine University Hampton of Athens University Otterbein University University of Minnesota at Duluth University Inst. of Texas at Austin Pontificia Universidad Catolica delnacional Peru Nucl. Reas. Moscow Universidad de Ingeniería Centro Brasileiro de Pesquisas Físicas University of Pittsburgh Mass. Col. Lib. Arts Universidad Técnica Federico Santa María Fermilab University of Rochester Northwestern University University of Florida Rutgers University William and Mary Université University de Genève of Chicago Tufts University Universidad de Guanajuato University of California at Irvine Hampton University University of Minnesota at Duluth Inst. Nucl. Reas. Moscow Universidad Nacional de Ingeniería Mass. Col. Lib. Arts Universidad Técnica Federico Santa María Northwestern University William and Mary University of Chicago David"Schmitz,"UChicago" Fermilab"Joint"Experimental=Theore?cal"Seminar"="May"1,"13" 3 5"

4 NuMI Beam figure courtesy Z. Pavlović 1 GeV/c protons from Main Injector. Graphite target ME run started September 13. 4

5 Backup

6 MINERvA Detector 1 modules for tracking and colorimetry (3k readout channels) Completion in Spring 1,. The MINOS near detector serves as a muon spectrometer. Nucl. Inst. and Meth. A743 (14) 13 6

7 Neutrino Event Generator (GENIE) Includes a lot of physics: electron scattering, final state interaction (FSI) models, and nuclear physics models Provides framework for realising physics analysis for neutrino (especially oscillation) experiments TK NOvA, IceCube, MINERvA D. Schmitz Events/.1 GeV Ratio to no oscillations DATA ν µ +ν µ CCQE ν µ +ν µ CC nonqe ν e +ν e CC NC MC Bestfit > 5 Reconstructed ν Energy (GeV) arxiv: and Patrick de Perio s talk Phys. Rev. Lett. 11, 18181, 14 7 σ cm / per nucleus ν µ + A µ MINERvA <A> =1 1 SciBooNE <A> =1 KK <A> =1 3 TK <A> =1 4 BEBC <A> = 5 CHARM II <A> =1 6 SKAT <A> 3 7 ArgoNeuT <A> =4 9 GENIE v.6. + π + + A 1 1 Neutrino Energy (GeV) σ cm / per nucleus ν + A µ + µ + π MINERvA <A> =1 8 BEBC 5 CHARM 6 SKAT <A> = II <A> =1 <A> =3 7 ArgoNeuT 9 GENIE v.6. <A> =4 + A 1 1 Neutrino Energy (GeV)

8 Publication forthcoming on arxiv: Results: Charged Pion Production µ µ 3.4e POT neutrinos W p(n) p(n) 8

9 Event selection Events e+ POT ν µ + A µ + π + + A Coh Pion Pion Proton Other Events e+ POT + π + A µ + ν µ + A Coh Pion Pion Proton Other Proton Score Proton Score Events contain one muon matched in MINOS. Events contain at least one hadron track. Only tracks which stop in the Ecal or tracker region are accepted. Pions are identified by de/dx, and the existence of a Michel electron at the end of the pion track. 9

10 MC scaled by.7 Results n pions 1 pion 1 pion 1

11 Take away Measurements constrains interaction rate and final state interactions in pion production. The contribution from Final State Interaction (FSI) is significant. Needed to improve signal and background predictions for oscillation experiments. Agreement with GENIE. 11

12 Publication forthcoming Results: Coherent Pion Production 3.4e POT neutrinos.1e POT antineutrinos (_ ) ν μ q t W +_ μ +_ π +_ Existence of pion and muon with no nucleon breakup (quiet vertex) and low momentum transferred between nucleus and pion. A A 1

13 Event selection Events /.5 (GeV/c) Events /.5 (GeV/c) 7 DATA antineutrino ν µ.1e+ POT Reconstructed t = (qp ) (GeV/c) ν µ + A µ + + π + A µ + + π.1e+ POT π COH QE RES W< <W<. W>. Other All Background Tuned Reconstructed t = (qp ) π + A + A Monte Carlo Tuned Bkgd (GeV/c) Events have almost no vertex energy. Separation of coherent scattering from incoherent background by slope of t due to the slope being different for diffractive and resonant processes. Sideband is selected as the incoherent background, is tuned to MC to minimize χ 13 Events /.5 (GeV/c) Events /.5 (GeV/c) ν µ 3.5e+ POT + A µ + π + + A Reconstructed t = (qp ) (GeV/c) neutrino ν µ 3.5e+ POT Reconstructed t = (qp ) π + A µ π DATA COH QE RES W< <W<. W>. Other All Background Tuned + π + + A Monte Carlo Tuned Bkgd (GeV/c)

14 Results: Cross section antineutrino ) 1 /Degree/C (cm dσ dθ π ν µ θ π + A µ + + π + A.1e+ POT DATA GENIE v w/r to Beam (Degrees) ) 1 /C σ (cm ν + A µ + µ + π + A.1e+ POT DATA GENIE v Neutrino Energy (GeV) ) 1 /GeV/C (cm dσ de π ν µ + A µ + + π + A Pion Energy (GeV).1e+ POT DATA GENIE v.6. ) 1 /Degree/C neutrino (cm dσ dθ π ν µ θ π + A µ + π + + A 3.5e+ POT DATA GENIE v.6. w/r to Beam (Degrees) ) 1 /C σ (cm ν + π + µ + A µ + A 3.5e+ POT DATA GENIE v Neutrino Energy (GeV) ) 1 /GeV/C (cm dσ de π ν µ + A µ + π + + A Pion Energy (GeV) 3.5e+ POT DATA GENIE v.6. 14

15 Take away shows a harder and more forward pion distribution than GENIE. The selection of low t events allows a model independent measurement of coherent pion production. Can be used to set systematic for oscillation experiments. In the NuMI ME configuration, multiple passive targets (Pb, Fe, C) will allow a measurement of A dependence. 15

16 Published arxiv: Results: Inclusive Charged Current (GeV/c) Reconstructed Q W = GeV W = 1.3 GeV Reconstructed Bjorken x Scattering e POT neutrinos 16

17 Event Selection Events must have a muon in MINOS. Target vertex must be in passive target or neighbouring scintillator. Neutrino energy between and GeV. Muon angle < 17 deg Pb / 1 Fe 66kg / 33kg Target N Events / Module 3 C / 1 Fe / 1 Pb 166kg / 169kg / 11kg True Event Origins Reconstructed Vertex Z Each Bunch AreaNormalized Target 3 Target 4 Target 5.3 Pb 8kg Carbon Iron Lead Scintillator Adjusted Vertex Z (cm).5 Fe /.5 Pb 161kg/ 135kg Gives MINOS acceptance (restricts kinematics). Gives estimate of contamination from scientillator.

18 Ratio Results / σ CH Ratio of σ C : σ CH χ /ndf = 11.31/8 = 1.41 Simulation σ C / σ CH σ Fe / σ CH σ Pb Neutrino Energy (GeV) Ratio of σ Fe : σ CH χ /ndf = 9.76/8 = Neutrino Energy (GeV) Ratio of σ Pb : σ CH χ /ndf = 5.3/8 =.63 Simulation Simulation No tension between data and MC dσ CH dx / χ /ndf = 6.5/6 = 1.1 Simulation Ratio of dσ C dx : dσ CH dx Tension between data and MC dσ C dx dσ CH dx / dσ Fe dx dσ CH dx / dσ Pb dx Reconstructed Bjorken x Ratio of dσ Fe : dσ CH dx dx χ /ndf = 5.87/6 = 4.31 Simulation Reconstructed Bjorken x Simulation Ratio of dσ Pb dx χ /ndf = 58.46/6 = 9.74 : dσ CH dx Neutrino Energy (GeV) Reconstructed Bjorken x

19 Take away This is not deep inelastic scattering. Theory input needed! is not reproduced by simulation. (GeV/c) Reconstructed Q W = GeV W = 1.3 GeV Reconstructed Bjorken x Can be used to improve estimate of systematic for oscillation experiments. Unexpected excess at high x and deficit at low x points to improvements needed in models ( fermi motion +? and shadowing). 19

20 Published in PRL and arxiv: and arxiv: Results:QuasiElastic Scattering p(n) n(p) 3.98e POT neutrinos W 1.7e POT antineutrinos µ µ

21 Event Selection, Results and Take away Simple event selection requires single track with matching track in MINOS. Requires no more than 1() additional blobs for antiν(ν) Basic relativistic fermi gas model disfavored. Increasing axial mass disfavored.

22 Conclusions and Future MINERvA is important in developing neutrino generators (GENIE), required for oscillation experiments. MINERvA ME data run has begun. Possibilities to extend the MINERvA program. Many analyses in progress, expect CCPi, K production, NuE elastic in the coming months. Some results show broad agreement with model predictions and others significant disagreement. No need to PANIC, NOW we have observation.