July 2007 HARP results EPS2007 Manchester Alain Blondel New Results from HARP A HAdRon Production experiment at the CERN PS (PS214) Atmospheric Neutrino Flux Accelerator Neutrino Beams: K2K and MiniBooNE Hadron Production Models Neutrino Factory Overview of new results Alain Blondel, University of Geneva, on behalf of the HARP collaboration

July 2007 HARP results EPS2007 Manchester Alain Blondel Università degli Studi e Sezione INFN, Bari, Italy Rutherford Appleton Laboratory, Chilton, Didcot, UK Institut für Physik, Universität Dortmund, Germany Joint Institute for Nuclear Research, JINR Dubna, Russia Università degli Studi e Sezione INFN, Ferrara, Italy CERN, Geneva, Switzerland TU Karlsruhe, Germany Section de Physique, Université de Genève, Switzerland Laboratori Nazionali di Legnaro dell' INFN, Legnaro, Italy Institut de Physique Nucléaire, UCL, Louvain-la-Neuve, Belgium Università degli Studi e Sezione INFN, Milano, Italy P.N. Lebedev Institute of Physics (FIAN), Russian Academy of Sciences, Moscow, Russia Institute for Nuclear Research, Moscow, Russia Università "Federico II" e Sezione INFN, Napoli, Italy Nuclear and Astrophysics Laboratory, University of Oxford, UK Università degli Studi e Sezione INFN, Padova, Italy LPNHE, Université de Paris VI et VII, Paris, France Institute for High Energy Physics, Protvino, Russia Università "La Sapienza" e Sezione INFN Roma I, Roma, Italy Università degli Studi e Sezione INFN Roma III, Roma, Italy Dept. of Physics, University of Sheffield, UK Faculty of Physics, St Kliment Ohridski University, Sofia, Bulgaria Institute for Nuclear Research and Nuclear Energy, Academy of Sciences, Sofia, Bulgaria Università di Trieste e Sezione INFN, Trieste, Italy Univ. de Valencia, Spain The HARP Collaboration 24 institutes ~120 collaborators

July 2007 HARP results EPS2007 Manchester Alain Blondel Oscillation experiments (K2K): near, far detectors Far flux different from near flux (solid angle) in a way that is sensitive to primary hadron (p,θ) distribution. Also: neutrino cross-sections are poorly known at low energies Near detector is/will-be also a cross-section measurement device PROVIDED FLUX IS KNOWN ==> hadron production measurements far/near ratio very much like an oscillation!

July 2007 HARP results EPS2007 Manchester Alain Blondel Hadron production on nuclear targets is a) complicated b) uninteresting for hadronic physics c) difficult to measure well ==> data are sparse and Monte-Carlos are very uncertain d) absolutely mandatory for neutrino beam experiments e) also very useful for e.g. LHC simulations measure!

July 2007 HARP results EPS2007 Manchester Alain Blondel HARP approved 2000 built in 17 months run sept > nov triggers at each of these settings Beam line PID Forward detectors (pions, Kaons) --> neutrino beams - K2K, - MiniBooNE, - atmospheric, - Low-medium energy superbeam(s) Large Angle detectors -->neutrino factory Target material Target length (  ) Beam Momentum (GeV) #events (millions) Solid targets Be 2 (2001) ±3 ± 5 ± 8 ± 12 ± 15 For negative polarity, only 2% and 5% C Al Cu Sn Ta Pb K2K Al 5, 50, 100, replica MiniBooNE Be Cu “button” Cu+12.9, Cu “skew” Cu Cryogenic targets N7N7 6 cm ±3 ± 5 ± 8 ± 12 ± D1D1 H1H1 H2H2 18 cm±3, ±8, ± Water H20H2010, , +8(10%) 9.6

July 2007 HARP results EPS2007 Manchester Alain Blondel

HARP publications Detectors and performance description Laser-Based Calibration for the HARP Time of Flight System M. Bonesini et al, IEEE TRANS. NUCL. SCIENCE, VOL. 50, NO. 4, AUGUST The time-of-flight TOFW detector of the HARP experiment: construction and performance M. Baldo-Ceolin et al, Nucl. Instr. Meth. A 532 (2004) 548–561 Physics Performance of the Barrel RPC System of the HARP Experiment Bogomilov et al. IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 54, NO. 2 (2007) Particle identification algorithms for the HARP forward spectrometer M. G. Catanesi et al, Nucl.Instrum.Meth. A521: (2007) The HARP Detector at the CERN PS G. Catanesi et al Nucl. Instrum. Meth. A571: (2007), (2007) V. Ammosov et al, Nucl. Instrum. Meth. A571: (2007)

July 2007 HARP results EPS2007 Manchester Alain Blondel HARP publications Forward analysis Measurement of the production cross-section of positive pions in p-Al collisions at 12.9 GeV/c (K2K target measurement) M.G. Catanesi et al, hep-ex/ , Nucl. Phys. B732: 1-45 (2006) Measurement of the production cross-section of positive pions in the collision of 8.9 GeV/c protons on beryllium (MiniBooNE target measurement) M.G. Catanesi et al, hep-ex/ v2 to appear in Eur. Phys. J. C

July 2007 HARP results EPS2007 Manchester Alain Blondel HARP publications Large Angle analysis (Neutrino Factory measurements) Measurement of the production of charged pions by protons on a tantalum target M.G. Catanesi et al, arXiv: v1 to appear in Eur. Phys. J. C Charged pion production by 3 GeV/c–12 GeV/c protons on a carbon target M.G. Catanesi et al, submitted to Eur. Phys. J. C Large-angle production of charged pions by 3 GeV/c–12 GeV/c protons on copper and tin targets M.G. Catanesi et al, submitted to Eur. Phys. J. C

July 2007 HARP results EPS2007 Manchester Alain Blondel HARP BEAM COUNTERS --identify and count incoming particles --define beam particle impact in target + empty target runs to subtract effect of non-target material and count beam composition in electrons and muons

July 2007 HARP results EPS2007 Manchester Alain Blondel  K p TOF for p= N cherenkov for p below pion threshold HARP forward electrons hadrons electrons hadrons Calorimeter E/p and E(1st layer)/E for p above pion threshold

July 2007 HARP results EPS2007 Manchester Alain Blondel p(GeV/c) θ(rad) region of interest for MiniBooNE

July 2007 HARP results EPS2007 Manchester Alain Blondel

Figure 9 Muon neutrino fluxes in the K2K experiment as a function of neutrino energy E, as predicted by the default hadronic model in the K2K beam Monte Carlo simulation (dotted histograms),and by the HARP  + production measurement (filled circles with error bars). Left: unit-area normalized flux predictions at the K2K near (top) and far (bottom) detector locations,  near and  far ; right : the far – to – near flux ratio (empty squares with error boxes show the K2K model results), showing the precision improvement brought by the HARP data.

July 2007 HARP results EPS2007 Manchester Alain Blondel no oscillation flux*0.6 best osc. fit Reconstructed « single ring » Quasi-elastics in SuperKamiokande ==> spectral shape + normalization show oscillation (no oscillation curve for demonstration only) K2K final results (using HARP input, 4.1 -> 4.4  C.L. improved by factor 3) K2K results (incl. HARP) M. H. Ahn et al., K2K Collaboration, Phys. Rev. D74 (2006)

July 2007 HARP results EPS2007 Manchester Alain Blondel HARP Be 5% 8.9 GeV/c Results HARP results (data points), parametrization of HARP results (histogram) 0.75<p<5 GeV/c 30<theta<210 mrad Crucial for MiniBooNE which has no near detector!

July 2007 HARP results EPS2007 Manchester Alain Blondel Systematic errors here: forward 8.9 GeV/c Berylium (MiniBooNE)

July 2007 HARP results EPS2007 Manchester Alain Blondel “Large Angle” analysis beam momenta: 3, 5, 8, 12 GeV/c events: require trigger in ITC (cylinder around target) TPC tracks: >11/20 points, momentum measured and track originating in target PID selection additional selection to avoid track distortions due to ion charges in TPC: first part of spill (30-40% of data kept, correction available for future improvement) Corrections: Efficiency, absorption, PID, momentum and angle smearing by unfolding method (same as pC data analysis in forward spectrometer) Backgrounds: secondary interactions (simulated) low energy electrons and positrons (all from  0 ) predicted from  + and  - spectra (iterative) and normalized to identified e +-.

July 2007 HARP results EPS2007 Manchester Alain Blondel Pion production yields p-Ta  + forward 0.35 <  < 1.55 backward 1.55 <  < 2.15 p S. Borghi

July 2007 HARP results EPS2007 Manchester Alain Blondel p-Ta   forward 0.35 <  < 1.55 backward 1.55 <  < 2.15 Pion production yields

July 2007 HARP results EPS2007 Manchester Alain Blondel Neutrino factory study d  /d  cross-sections can be fed into neutrino factory studies to find optimum design Warning the above has fixed integration range, but optimization may be momentum dependent yield/E kin

July 2007 HARP results EPS2007 Manchester Alain Blondel

Conclusions HARP has taken a comprehensive set of data and begin to produce hadron production cross-sections with errors in the 4-8% range over a large fraction of phase-space Started with forward analysis for K2K and MiniBooNE and Large angle Tantalum (Nufact) – only pions Will continue with analysis of other targets (automated procedure) Analysis improvements to come: Forward Kaon production Large angle analysis full spill analysis

July 2007 HARP results EPS2007 Manchester Alain Blondel back ups

July 2007 HARP results EPS2007 Manchester Alain Blondel cryogenic H2 target

July 2007 HARP results EPS2007 Manchester Alain Blondel

elastic scattering provides 1. calibration of momentum scale of forward spectrometer (vs angle of LA scattered particle) 2. calibration of large angle momentum scale (vs angle of F scattered particle) 3. measurement of large angle track resolution and efficiency

July 2007 HARP results EPS2007 Manchester Alain Blondel efficiency (here: vicinity of azymuthal spokes) data Mont-Carlo resolution

July 2007 HARP results EPS2007 Manchester Alain Blondel Former HARP members (Dydak et al) claim that there is a bias of "15% at 600 MeV/c" in HARP TPC analysis. This is clearly not the case in the H2 target <-- analysis Additional tests were performed e.g.  - p scattering with reversed magnet polarity, etc... (paper in preparation) Investigation will continue (track-by-track comparison) momentum scale in TPC

July 2007 HARP results EPS2007 Manchester Alain Blondel