July 2007 HARP results EPS2007 Manchester Alain Blondel New Results from HARP A HAdRon Production experiment at the CERN PS (PS214) Atmospheric Neutrino

July 2007 HARP results EPS2007 Manchester Alain Blondel

New Results from HARP

A HAdRon Production experiment at the CERN PS (PS214)

Atmospheric Neutrino FluxAccelerator Neutrino Beams: K2K and MiniBooNEHadron Production ModelsNeutrino Factory

Overview of new results

Alain Blondel, University of Geneva, on behalf of the HARP collaboration


Università degli Studi e Sezione INFN, Bari, ItalyRutherford Appleton Laboratory, Chilton, Didcot, UK Institut für Physik, Universität Dortmund, GermanyJoint Institute for Nuclear Research, JINR Dubna, RussiaUniversità degli Studi e Sezione INFN, Ferrara, ItalyCERN, Geneva, Switzerland TU Karlsruhe, GermanySection de Physique, Université de Genève, SwitzerlandLaboratori Nazionali di Legnaro dell' INFN, Legnaro, ItalyInstitut de Physique Nucléaire, UCL, Louvain-la-Neuve, BelgiumUniversità degli Studi e Sezione INFN, Milano, ItalyP.N. Lebedev Institute of Physics (FIAN), Russian Academy of Sciences, Moscow, RussiaInstitute for Nuclear Research, Moscow, RussiaUniversità "Federico II" e Sezione INFN, Napoli, ItalyNuclear and Astrophysics Laboratory, University of Oxford, UKUniversità degli Studi e Sezione INFN, Padova, Italy LPNHE, Université de Paris VI et VII, Paris, FranceInstitute for High Energy Physics, Protvino, RussiaUniversità "La Sapienza" e Sezione INFN Roma I, Roma, ItalyUniversità degli Studi e Sezione INFN Roma III, Roma, ItalyDept. of Physics, University of Sheffield, UKFaculty of Physics, St Kliment Ohridski University, Sofia, BulgariaInstitute for Nuclear Research and Nuclear Energy, Academy of Sciences, Sofia, BulgariaUniversità di Trieste e Sezione INFN, Trieste, ItalyUniv. de Valencia, Spain

TheThe HARP HARPCollaborationCollaboration

24 institutes24 institutes~120 collaborators~120 collaborators


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

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 1 2 3 4 5Neutrino Energy (GeV)

(xL

)/(

xL

)

SK

SK

FD

FD

22

far/near ratiovery much like an oscillation!


Hadron production on nuclear targets isa) complicated b) uninteresting for hadronic physics c) difficult to measure well

==> data are sparse and Monte-Carlosare very uncertain

d) absolutely mandatory for neutrino beam experimentse) also very useful for e.g. LHC simulations

measure!


HARP approved 2000built in 17 monthsrun sept. 2001 -> nov 2002

106 triggers at each of thesesettings

Beam line PIDForward detectors (pions, Kaons) --> neutrino beams - K2K, - MiniBooNE, - atmospheric, - Low-medium energy superbeam(s)

Large Angle detectors-->neutrino factory

Targetmaterial

Target length

()

BeamMomentum

(GeV)

#events(millions

)

Solid targets

Be 2

(2001)

5

100

±3± 5± 8

± 12± 15

For negative polarity, only 2% and 5%

233.16

C

Al

Cu

Sn

Ta

Pb

K2K Al 5, 50, 100, replica

+12.9 15.27

MiniBooNE Be +8.9 22.56

Cu “button”

Cu +12.9, +151.71

Cu “skew” Cu 2 +12 1.69

Cryogenictargets

N7

6 cm

±3± 5± 8

± 12± 15

58.4308

D1

H1

H2 18 cm ±3, ±8, ±14.5 13.83

WaterH20 10, 100 +1.5,

+8(10%)9.6



HARP publications

Detectors and performance description

Laser-Based Calibration for the HARP Time of Flight SystemM. Bonesini et al, IEEE TRANS. NUCL. SCIENCE, VOL. 50, NO. 4, AUGUST 2003 1053

The time-of-flight TOFW detector of the HARP experiment: construction and performanceM. Baldo-Ceolin et al, Nucl. Instr. Meth. A 532 (2004) 548–561

Physics Performance of the Barrel RPC System of the HARP ExperimentBogomilov et al. IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 54, NO. 2 (2007)

Particle identification algorithms for the HARP forward spectrometerM. G. Catanesi et al, Nucl.Instrum.Meth. A521: 899-921 (2007)

The HARP Detector at the CERN PSG. Catanesi et al Nucl. Instrum. Meth. A571: 527-561 (2007), 564-573(2007)V. Ammosov et al, Nucl. Instrum. Meth. A571: 561-564 (2007)


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/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, hep-ex/0702024v2 to appear in Eur. Phys. J. C


HARP publications

Large Angle analysis(Neutrino Factory measurements)

Measurement of the production of charged pions by protons on a tantalum targetM.G. Catanesi et al, arXiv:0706.1600v1 to appear in Eur. Phys. J. C

Charged pion production by 3 GeV/c–12 GeV/c protons on a carbon targetM.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 targetsM.G. Catanesi et al, submitted to Eur. Phys. J. C


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


Kp

TOF for p=2+-0.25 Ncherenkov for p below pion threshold

HARP forward

electrons

hadrons

electronshadrons

Calorimeter E/p and E(1st layer)/Efor p above pion threshold


p(GeV/c)

θ(rad) region of interest for MiniBooNE



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.


no oscillation

flux*0.6

best osc. fit

Reconstructed « single ring » Quasi-elastics in SuperKamiokande

==> spectral shape + normalizationshow 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) 072003


HARP Be 5% 8.9 GeV/c Results

HARP results (data points), parametrization of HARP results (histogram)

0.75<p<5 GeV/c30<theta<210 mradCrucial for MiniBooNE which has no near detector!


Systematic errors here: forward 8.9 GeV/c Berylium (MiniBooNE)


“Large Angle” analysisbeam 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 targetPID selectionadditional 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+-.


Pion production yields p-Ta +

forward0.35 < < 1.55

backward1.55 < < 2.15

p

S. Borghi


p-Ta

forward0.35 < < 1.55

backward1.55 < < 2.15

Pion production yields


Neutrinofactorystudy

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/Ekin

+

-

+

-



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 productionLarge angle analysis full spill analysis


back ups


cryogenic H2 target



elastic scattering provides1. 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


efficiency (here: vicinity of azymuthal spokes)

data Mont-Carlo

resolution


Former HARP members(Dydak et al) claim thatthere 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 withreversed magnet polarity, etc...(paper in preparation)Investigation will continue(track-by-track comparison)

momentum scale in TPC


Documents

July 2007 HARP results EPS2007 Manchester Alain Blondel New Results from HARP A HAdRon Production experiment at the CERN PS (PS214) Atmospheric Neutrino