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
July 2007 HARP results EPS2007 Manchester Alain Blondel
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
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
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!
July 2007 HARP results EPS2007 Manchester Alain Blondel
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!
July 2007 HARP results EPS2007 Manchester Alain Blondel
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
July 2007 HARP results EPS2007 Manchester Alain Blondel
July 2007 HARP results EPS2007 Manchester Alain Blondel
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)
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/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
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 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
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
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
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
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 + 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
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/c30<theta<210 mradCrucial 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” 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+-.
July 2007 HARP results EPS2007 Manchester Alain Blondel
Pion production yields p-Ta +
forward0.35 < < 1.55
backward1.55 < < 2.15
p
S. Borghi
July 2007 HARP results EPS2007 Manchester Alain Blondel
p-Ta
forward0.35 < < 1.55
backward1.55 < < 2.15
Pion production yields
July 2007 HARP results EPS2007 Manchester Alain Blondel
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
+
-
+
-
July 2007 HARP results EPS2007 Manchester Alain Blondel
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 productionLarge 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
July 2007 HARP results EPS2007 Manchester Alain Blondel
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
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 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
July 2007 HARP results EPS2007 Manchester Alain Blondel