Production Studies: the HARP results WP2 December 2008 EURO ν Production Studies: the HARP results WP2 December 2008 Maria Gabriella Catanesi INFN Bari Italy

Outline Prospective & conclusions Why HARP ? The detector HARP results: K2K & MiniBoone fluxes Super Beams & Neutrino Factory Design Atmospheric fluxes ( < 15 GeV) Hadron Production Models Prospective & conclusions

Harp Inaugurates a new era in Hadron Production for Neutrino Physics: Based on a design born for Heavy Ions physics studies Full acceptance with P.Id. High event rate capability (3KHz on TPC) Built on purpose Collaboration includes members of Neutrino Oscillation & Cosmic rays experiments (124 Physicists from 20 institutions) And makes measurements on specific targets of existing neutrino beams.

Existing measurements at the end of the millennium 1 GeV 10 100 1 TeV Daughter energy Boxes show importance of phase space region for contained atmospheric neutrino events. Barton et. al. Overall quoted errors Absolute rates: ~15% Ratios: ~5% These figures are typical of this kind of detector setup Abbott et. al. Measurements. 1-2 pT points 3-5 pT points >5 pT points 1 GeV 10 100 1 TeV Parent energy Eichten et. al.

HARP: Data taking summary HARP took data at the CERN PS T9 beam line in 2001-2002 Total: 420 M events, ~300 settings SOLID: CRYOGENIC: n EXP K2K: Al MiniBoone: Be LSND: H2O 5% 50% 100% Replica 10% +12.9 GeV/c +8.9 GeV/c +1.5 GeV/c

Detector layout Forward spectrometer Large Angle spectrometer 30 mrad <  < 210 mrad. 750 MeV/c < p < 6.5 GeV/c K2K,MiniBoone, Cosmic rays Forward spectrometer Large Angle spectrometer Large Angle Spectrometer: 0.35 rad <  < 2.15 rad 100 MeV/c < p < 700 MeV/c Super Beams - Nufactories More details in the NIM paper “The Harp Detector @ the CERN PS”

FORWARD ANALYSIS

FW: Momentum Resolution ELASTICS theta-p plane: 0.5 1.5 3 5 8 0. 0.1 0.2 TOF elastics empty target beam TOF BEAM open: data filled: MC

FW: PID principle CAL TOF CERENKOV CERENKOV TOF

Relevance of HARP for K2K neutrino beam One of the largest K2K systematic errors comes from the uncertainty of the far/near ratio pions producing neutrinos in the oscillation peak measured by HARP oscillation peak K2K far/near ratio 0.5 1.0 1.5 2.0 2.5 En (GeV) K2K interest Beam MC confirmed by Pion Monitor Beam MC

Far/Near Ratio in K2K Predicted Flux Shape Predicted Far/Near Ratio Near Detector Far Detector HARP gives ~ factor 2 error reduction across all energies Nucl.Phys.B732:1-45,2006 hep-ex/0510039

MiniBoone : Harp Be 8.9 GeV 5% λ π+ Harp Forward Spectrometer Acceptance (But also SCIBOONE)

HARP Be 8.9 GeV/c data Sanford-Wang parametrization

More HARP data for accurate flux predictions coming: main source of νe flux for MiniBooNE K± production data thick targets π - production data Direct measurement with rescattering and absorption Anti-neutrino flux measurement p K p

- data needed for MiniBooNE antineutrino flux Paper in preparation

Atmospheric neutrino fluxes primary flux Primary flux is now considered to be known to better than 10% Most of the uncertainty comes from the lack of data to construct and calibrate a reliable hadron interaction model. Model-dependent extrapolations from the limited set of data leads to about 30% uncertainty in atmospheric fluxes  cryogenic targets N2,O2 hadron production decay chains

Model comparison: p+C→++X

Results for p+O2 or p+N2 cryo targets

More targets, more momenta Available: Be, C, Al, Cu, Sn, Ta, Pb at 3, 5, 8, 12 GeV/c Can be used for complete parametrizations or tuning of models Low energy data useful for cascade calculations These data were taken with lower statistics than the dedicated runs for K2K and MiniBooNE Some example spectra:

HARP pBe @ 3, 5, 8, 12 GeV/c

HARP pAl @ 3, 5, 8, 12 GeV/c

HARP pPb @ 3,5, 8, 12 GeV/c

HARP pA A-dependence

HARP p-A trends with A

Comparisons with models Some examples

pAl @ 12.9 GeV/c versus GEANT4

Model comparison: p+C→+X DPMJET: Glauber cascade, fits best for pi+ GHEISHA: parameterization for nucleus, interpolation and extrapolation UrQMD: quantum mechanics, geometrical collision probability, parameterization for nucleons

π± Ta -> π± X 3 GeV/c

π± Ta -> π± X 5 GeV/c

π± Be -> π± X 5 GeV/c

Large Angle Analysis

LA Spectrometer performance p-p PID with dE/dx momentum calibration: cosmic rays elastic scattering momentum resolution PID: dE/dx used for analysis TOF used to determine efficiency p-e PID with dE/dx elastic scattering: absolute calibration of efficiency momentum angle (two spectrometers!)

momentum scale efficiency The elastic scattering benchmark [1/p (predicted-measured)]/(1/p) Comparison of predicted vs measured track allows LA tracking benchmark missing mass peak from large angle proton track (position of peak verifies momentum scale -- +15% shift is completely excluded) efficiency Momentum scale Sys. Error < 3%

Stability from LH2 target to other targets consider average momentum of protons with dE/dx [7-8] MIPs H2 setting H2 Al 13 12 8 5 3 Carbon 12 8 5 3 Tin 12 8 5 3 2% Copper 12 8 5 3 Be 12 9 8 5 3 Lead 12 8 5 3 Ta 12 8 5 3

Example of future projects Primary energy, target material and geometry, collection scheme maximizing the π+, π - production rate /proton /GeV knowing with high precision (<5%) the PT distribution A possible scenario: from 2.2 GeV/c to 8 GeV/c proton linac. Phase rotation longitudinally freeze the beam: slow down earlier particles, accelerate later ones need good knowledge also of PL distribution 36

Neutrino factory study + - Ta Target Data + - yield/Ekin ds/dq cross-sections can be fed into neutrino factory studies to find optimum design The optimal energy is between 5 and 8 GeV/c published on EPJC

Low θ tracks in the TPC: (250 – 350 mrad) We can measure these tracks but: Worse resolution & lower efficiency

Neutrino factory study (cont’) it’s also possible to enlarge the phase space (if we accept larger errors) On going analysis 39

π-π+ ratios for light and heavy nuclei

Pion yields comparison of p+ and p- and yields for p-A for Be, C, Cu, Sn, Ta and Pb forward production only 0.35 < q < 0.95 rad p+ p-

Pion yields A-dependence of p+ and p- and yields for p-A for Be, C, Cu, Sn, Ta and Pb (3, 5, 8, 12 GeV/c) forward production only 0.35 < q < 1.55 rad p+ p-

proton beams on long targets Data analysed on tantalum and carbon targets (lead later) Especially useful for the neutrino factory target Interesting to tune models for re-interactions (and shower calculations in calorimeters etc.) As for the thin targets, corrections for the absorption and re-interaction of the produced particles are made NO correction is made for the absorption and re-interaction of the beam proton (this is what we want to measure) Data are not directly applicable: our targets are 30mm in diameter: more re-interactions of the scattered proton

LONG C TARGET p-C p- PRELIMINARY forward 0.35 < q < 1.55 backward 1.55 < q < 2.15 44

100% vs 5% TARGET FW and BW p-C p+ 100% l target 5% l target PRELIMINARY

100% / 5% TARGET bin-by-bin ratio 5 GeV/c beam: p-C p+/- Large corrections ! If no effect from absorption of p: expect ratio = 1 If all interacting p are lost: expect ratio = 0.65 p- p+ PRELIMINARY

bin-by-bin ratio 12 GeV/c beam: p-C p+/- 100% / 5% TARGET If no effect from absorption of p: expect ratio = 1 If all interacting p are lost: expect ratio = 0.65 p+ p-

100% / 5% TARGET bin-by-bin ratio 5 GeV/c beam: p-Ta p+/- If no effect from absorption of p: expect ratio = 1 If all interacting p are lost: expect ratio = 0.65 p+ p-

100% / 5% TARGET bin-by-bin ratio 12 GeV/c beam: p-Ta p+/- If no effect from absorption of p: expect ratio = 1 If all interacting p are lost: expect ratio = 0.65 p- p+

HARP publications Forward analysis In preparation : 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/0510039, 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, Eur.Phys.J.C52:29-53,2007. Measurement of the production cross-section of pi+ in p-C and pi- C Interactions at 12 GeV/c M.G.Catanesi et al : Astroparticle Physics - volume/issue: 29/4 pp. 257-281 Forward production of pi+/pi- in p-O2 and pN2 interactions at 12 GeV/C M.G.Catanesi et al : Astroparticle Physics - volume/issue: 30/4 pp. 120-150 Forward production of charged pions in the HARP experiment with incident pi+/pi- on nuclear targets M.G.Catanesi et al : Accepted by Nuclear physics A In preparation : Full characterization of the MiniBoone/SciBoone  neutrino beam (pi-, kaon, protons, thick and replica target) Forward production of charged pions with incident protons on different nuclear targets Forward production of charged pions with incident protons and pions on different nuclear thick targets

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, Eur. Phys. J. C51 (2007) 787 Large-angle production of charged pions by 3 GeV/c–12 GeV/c protons on carbon copper and tin targets M.G. Catanesi et al, Eur. Phys. J. C53:177-204,2008 Large-angle production of charged pions by 3 GeV/c–12 GeV/c protons on a beryllium , aluminum and lead targets: M.G. Catanesi et al, Eur. Phys. J. C54:37-60,2008 Large-angle production of charged pions in the HARP experiment with incident protons on nuclear targets : M.G.Catanesi et al. Phys. Rev. C 77, 055207 (2008) In preparation : Large-angle production of charged pions in the HARP experiment with incident pions on nuclear targets : M.G. Catanesi et al. (Draft in preparation ) (beams 3 GeV/c -12.9 GeV/c , Al, Be,C, Cu, Pb,Sn,Ta targets) Large Angle production of charged pions with incident protons and pions on different nuclear thick targets

Conclusions HARP has made important contributions to hadronic cross-section measurements relevant to neutrino experiments: Aluminum results for K2K have used for final K2K publication. Beryllium results for MiniBooNE and SciBoone are also finals. These measurements are already being used by the MiniBooNE collaboration. Tantalum (and other targets results) for the Neutrino Factory studies are available Carbon ,N2, O2 data for atmospheric neutrino fluxes are ready. More production cross-section measurements are finished and can be used to tune hadron production models. All the previous listed results have been already published but many new results will be coming soon … stay tuned !

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About the discrepancy between the HARP results and those produced by the so called “Dydak group” Protons on Be

Protons on Be

About the discrepancy between the HARP results and those produced by the so called “Dydak group” Protons on Be

In Summary We don’t believe in this hypothesis because The Dydak group claims that the observed discrepancies should be interpreted as the consequence of a momentum bias (~15%) in our data We don’t believe in this hypothesis because This bias is excluded by the elastic scattering analysis The discrepancy is visible only for π+ The discrepancy is visible only at low θ The size of the discrepancy smootly depends from the beam energy No shift is observed in the peak position Any way the size of the effect is such that doesn’t change the optimal energy for the NF driver

Harp vs E910 (12 GeV/c P beam)