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Hadro-production measurements for the T2K experiment with the NA61/SHINE detector at the CERN SPS

Hadro-production measurements for the T2K experiment with the NA61/SHINE detector at the CERN SPS. n -Beam Characterization T2K. Cosmic-Ray Air Showers Pierre Auger + KASCADE. Search for Critical Point. NA61/SHINE (SPS Heavy Ion and Neutrino Experiment). Grandmother (beam particle).

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Hadro-production measurements for the T2K experiment with the NA61/SHINE detector at the CERN SPS

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  1. Hadro-production measurements for the T2K experiment with the NA61/SHINE detector at the CERN SPS

  2. n-Beam Characterization T2K Cosmic-Ray Air Showers Pierre Auger + KASCADE Search for Critical Point NA61/SHINE (SPS Heavy Ion and Neutrino Experiment) Grandmother (beam particle) Mother (secondary particle) n m p+C collisions p+C, p+C collisions A+A collisions Claudia Strabel, NA61 @ CERN SPS

  3. Physics Goals (I) • One of the main physics goals of NA61/SHINE: • T2K @ JPARC (Japan): • - Long baseline (295km) neutrino oscillation experiment • - Protons (30-50GeV) + carbon target (90cm) → intense nm-beam • - Neutrino spectra measured off-axis at the near and far detectors: ND280 and SK Precision measurements of hadron production for the prediction of n-fluxes at T2K p 2.5° ND p SK p accelerator facility 295km 280m 0m JPARC

  4. Physics Goals (II) • Main aims of T2K: • Search for and measurement of the nm→ neappearance • » improved sensitivity to the so far unknown mixing angle q13 • Refinement of nm disappearance measurements • » improved determination of q23 and Dm223 • Both analysis rely on the n spectra measured at SK and the predicted spectra at SK: • Far to Near (F/N) ratio R: is not constant with respect to En • → to predict the n flux correctly details of n parent hadro-production kinematics needed • m Flux • (normalized to SK) F/N Ratio (nm) En [GeV] En [GeV] Claudia Strabel, NA61 @ CERN SPS

  5. Physics Goals (III) • Simulated distributions of p and K whose daughter n pass through SK: • The goal is to reduce the error on the F/N ratio to a negligible level compared to other • contributions to the systematics (ND280 spectrum measurements, cross-section, efficiencies, etc.), • therefore the aims are: • To reach this precision we need ~200k reconstructed πtracks in p+C interactions at 31GeV/c • Furthermore, p and K from secondary interactions in the T2K target needed to be studied Measure K/p ratio with an uncertainty of 10% Predict Far/Near neutrino flux ratio to 3% Claudia Strabel, NA61 @ CERN SPS

  6. Analysis Strategies for T2K Strategy A • Measure the inclusive p+C cross section with a thin target over a broad kinematical • range and different particles (p, K, p) • Use the measured cross sections as input to the beam MC for generating the primary • interaction. Secondary interactions, however, will be described by hadronization • models (e.g. FLUKA) • Compare the MC predictions to the p/K yields measured off C-targets of different • lengths (e.g. T2K replica target) and adjust the model accordingly • Strategy B • Measure p/K yields off the T2K replica target • Use measured p/K yields as input to the beam MC • (no simulation of secondary interactions required) Claudia Strabel, NA61 @ CERN SPS

  7. NA61/SHINE – Fixed Target Experiment at CERN SPS NA49 Setup + Upgrades: 2007/11 PSD 2009/11 He BEAM PIPE • Large acceptance (up to 70%) spectrometer for charged particles • TPCs as main tracking devices • 2 dipole magnets with bending power of max 9 Tm over 7 m length (2007-Run: 1.14 Tm) • High momentum resolution: s(p)/p 2 ≈ 10-4 (GeV/c)-1 • Good particle identification: s(ToF-L/R) ≈100 ps, s(dE/dx)/<dE/dx> ≈ 0.04, s(minv) ≈ 5 MeV • New ToF-F to entirely cover T2K acceptance (s(ToF-F) ≈ 120 ps, 1<p <3 GeV/c, 50<Q<150 mrad) Claudia Strabel, NA61 @ CERN SPS

  8. Setup of Beam Line • Secondary hadron beam composed of 83.7% p+, • 14.7% p and 1.6% K+ • Proton beam particles identified by CEDAR (C1) and • threshold Cerenkov counters (C2) • Incoming p then selected by several scintillator counters • (S1, S2, V0, V1) → beam defined as B = S1•S2•V•C1•C2 • Trajectory of beam particles measured by the beam • position detectors(BPD-1/-2/-3) • Interactions in the target selected by anti-coincidence • of the beam particle with a small scintillator S4 (B•S4) All Beam Particles Triggered Protons (C1•C2) p p p K Beam Divergence Beam Spot at BPD3 Claudia Strabel, NA61 @ CERN SPS

  9. Setup of Beam Line – Target Thin Carbon Target T2K Replica Target • 2 different carbon targets (isotropic graphite, r = 1.84 g/cm3): Thin Carbon Target: - 2.5 x 2.5 x 2cm3, - int. length ~0.04 - used to evaluate inclusive x-sections T2K Replica Target: - Ø= 2.6cm x 90cm, - int. length ~1.9 - used to study secondary interactions • Aims of the first NA61 run in October 2007: - to set up and test the NA61 apparatus and the detector prototypes - to take pilot physics data for T2K with 30.9 GeV/c protons: Replica target: ~230k events Thin target: ~660k events Target out: ~80k events Claudia Strabel, NA61 @ CERN SPS

  10. Cross Section Normalization • The inclusive inelastic cross section of a particle type a can experimentally be expressed by n: target properties, Nbeam: # of incoming beam p, Ntrig: # of triggers, strig: trigger cross section, Dn: # of identified particles in a given bin p-q bin • strig thus involves the trigger rate and the target properties - The real interaction probability (Pint) is calculated as the difference of the rate obtained with and without target: r: density, L: length NA: Avogadro const. A: Atomic number Leff: effective length labs: abs. length - Interaction rate (Data): - Target out: (1.72 0.01)% - Target in: (7.07 0.01)% - Leff = 1.95 cm strig = 297.5 ± 0.7 ± 3.9 mb NA61 Preliminary  High Tout/Tin rate due to inelastic and elastic interactions in the material of the beamline Claudia Strabel, NA61 @ CERN SPS

  11. Inelastic Cross Section • sinel can be obtained from the strig by applying the following corrections: • 1) Subtract the contribution of elastic interactions due to large angle coherent scattering 2) Add the contribution of lost events where a secondary particle hits S4. Here, the major contribution comes from quasi-elastic scattering of the incident protons (sloss-p). Also secondary pions or kaons hitting S4 have to be taken into account (sloss-p/K) → Corrections have been estimated with Geant4 simulation NA61 Preliminary NA61 Preliminary stat. error syst. error → Preliminary value for the sinel is in good agreement with previous measurements Recalculated from G. Bellettini et al., Nucl. Phys. 79 (1966) 609, S.P. Denisov et. al. Nucl. Phys. B61 (1973) 62, A. Carroll et al., Phys. Lett. B80 (1979) 319

  12. Particle Identification – Strategy (I) • Energy Loss Measurements • Below p = 1 GeV/c dedicated dE/dx • analysis in 1/b2 region • For 1 < p < 4 GeV/c Bethe-Bloch curves • cross each other making particle • identification not reliable • → additional information from ToF • required • Above p = 4 GeV/c dE/dx analysis • in relativistic rise region Claudia Strabel, NA61 @ CERN SPS

  13. Particle Identification – Strategy (II) 2 < p < 3 GeV/c • Combined Energy Loss and • Time-of-Flight Measurements • In 1 < p < 6 GeV/c Time of Flight • measurements • Combined dE/dx and ToF analysis p K p e 3 < p < 4 GeV/c p K p e p 4 < p < 5 GeV/c K p p K p e Claudia Strabel, NA61 @ CERN SPS

  14. Particle Identification – Strategy (III) • Analysis of Negatively Charged Particles • The analysis of negatively charged hadrons, • h- analysis, from the primary vertex is based on • estimation that more than 90% of produced h- • in p+C collisions ast 31 GeV/c are p- mesons • The remaining small fraction includes K- and e- • and negligible number of anti-protons • Venus-GHEISHA and Geant MC simulation is • used to calculate corrections for geometrical • acceptance, reconstruction efficiency, weak • decays and lepton contamination • Finally corrected spectra of p- in all momentum • range are obtained Claudia Strabel, NA61 @ CERN SPS

  15. Results from dE/dx Analysis –p+ and p- below 1GeV/c NA61 Preliminary Claudia Strabel, NA61 @ CERN SPS

  16. Results from dE/dx and h- Analyses – p- NA61 Preliminary Systematical error below 20% Claudia Strabel, NA61 @ CERN SPS

  17. Results from h- and dE/dx+ToF Analyses – p- NA61 Preliminary Claudia Strabel, NA61 @ CERN SPS

  18. Results from h- Analysis – p- NA61 Preliminary Claudia Strabel, NA61 @ CERN SPS

  19. Summary and Outlook (I) • NA61/SHINE is a large acceptance hadron spectrometer at the CERN SPS which will • precisely measure the particle production from the interaction of a 30 GeV proton beam • on different Carbon targets • → Thin target: for the determination of inclusive cross sections → T2K replica target: for the study of secondary interactions in the T2K target • During the 2007 pilot run data on proton-Carbon interactions were registered • → good quality of data, though limited in statistics • → strig and sinel were measured. Preliminary sinel is in good agreement with previous • measurements → high quality of track reconstruction and particle identification has been achieved → the data and detailed simulations confirm that phase space needed for T2K measurements is covered → first preliminary hadron spectra for T2K have been obtained → work on T2K replica target data is in progress Claudia Strabel, NA61 @ CERN SPS

  20. Summary and Outlook (II) • 2009 successfully started on July 26th 2009 (~3 months of data taking) • → detector upgrades for this run • – TPC read-out and DAQ → increase of event rate by factor 10 (~70 Hz) • – new trigger system • – increased ToF-acceptance (pmin~ 1 GeV/c → 0.6 GeV/c) • – new Beam Position Detectors of 5 x 5 cm2 to fully cover x-section of the • T2K replica target • → ~3 weeks were dedicated to T2K measurments (p+C at 31 GeV/c) • → 6M interaction triggers collected for thin Carbon target and 3M triggers for the • T2K replica target Claudia Strabel, NA61 @ CERN SPS

  21. Long Target Data from 2009 Claudia Strabel, NA61 @ CERN SPS

  22. The NA61 Collaboration 121 scientists from 24 institutes and 14 countries University of Athens, Athens, Greece University of Bergen, Bergen, Norway University of Bern, Bern, Switzerland KFKI IPNP, Budapest, Hungary Cape Town University, Cape Town, South Africa Jagellionian University, Cracow, Poland Joint Institute for Nuclear Research, Dubna, Russia Fachhochschule Frankfurt, Frankfurt, Germany University of Frankfurt, Frankfurt, Germany University of Geneva, Geneva, Switzerland Forschungszentrum Karlsruhe, Karlsruhe, Germany Swietokrzyska Academy, Kielce, Poland Institute for Nuclear Research, Moscow, Russia LPNHE, Universites de Paris VI et VII, Paris, France Pusan National University, Pusan, Republic of Korea Faculty of Physics, University of Sofia, Sofia, Bulgaria St. Petersburg State University, St. Petersburg, Russia State University of New York, Stony Brook, USA KEK, Tsukuba, Japan Soltan Institute for Nuclear Studies, Warsaw, Poland Warsaw University of Technology, Warsaw, Poland University of Warsaw, Warsaw, Poland Rudjer Boskovic Institute, Zagreb, Croatia ETH Zurich, Zurich, Switzerland

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