H A R P A Hadron Production Experiment at the Proton Synchrotron at CERN Motivation for the HARP experiment The HARP Detector MiniBooNE and HARP

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 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 HARP Institutions

HARP Motivation (general) Measure absolute inclusive cross-sections for Hadron production with a range of targets (H,D,Be,C,O,N,Al,Sn,Ta,Pb) and primary proton energies (1.5 GeV/c to 15GeV/c).

HARP Motivation (specific) ● Neutrino Factory Design Atmospheric Neutrino Flux Calculations Neutrino Fluxes for MiniBooNE and K2K Input to Monte Carlo simulation packages

Neutrino Factory Need to Know: 1.  +,  - production rates for varying target materials, target size and proton beam energies (2-24GeV). 2. The P T distribution with high precision to optimize muon collection.

Atmospheric Neutrinos _ Need to Know: 1. Primary Cosmic Ray Flux* 2. Hadron Interaction Model** * known to better than 10% **limited data leads to ~30% uncertainty in atmospheric neutrino fluxes

HARP at the CERN PS 200 meters in diameter 28 GeV maximum energy Feeds into SPS Used to make anti-protons Used for target expr. - HARP

HARP at the CERN PS East Hall

T9 Secondary Beam at PS PS protons hit a target producing secondary particles. Particles are momentum selected allowing HARP to choose beam energy (2 -15 GeV). However, beam consists of different particles - mainly protons and pions. TOF measurements distinguish different particles in the beam before hitting the HARP target. NOTE: This is different from MiniBooNE. MiniBooNE gets 8 GeV protons directly from the Booster.

HARP Detector

HARP detector: Acceptance, PID, Redundancy TPC, momentum and PID (dE/dX) at large Pt TPC, momentum and PID (dE/dX) at large Pt Drift Chambers: Tracking and low Pt spectrometer Drift Chambers: Tracking and low Pt spectrometer 1.5 T dipole spectrometer Threshold gas Cherenkov:  identification at large Pl Threshold gas Cherenkov:  identification at large Pl 0.7T solenoidal coil Target-Trigger EM filter (beam muon ID and normalization) EM filter (beam muon ID and normalization) Drift Chambers: Tracking Drift Chambers: Tracking TOF:  identification in the low Pl and low Pt region TOF:  identification in the low Pl and low Pt region

HARP Detector TPC: - PID - momentum measurement for high p T particles NDC: -Momentum measurement for low p T forward particles Cherenkov: - PID for momentum >3.0 GeV/c TOF: - PID primarily for p < 3.0 GeV/c

HARP Detector

Time Projection Chamber - TPC p(GeV/c) Used for particle id:  /K up to 0.7 GeV/c  /p up to 1.2 and above 3 GeV/c want dE/dx resolution ~6% And momentum measurement: r-  resolution of 300  m p T resolution dp T /p T =0.033 p T

TPC Hits, ArCO2 Mixture, 0.7T Field, 10 cm C Target Prototype of the TPC simulation in the GEANT4 framework

Resistive Plate Chamber -RPC HV Gas

TPC & RPC

TPC - RPC Event

HARP Detector

Drift Chambers & Spectrometer Magnet 0.5 T Vertical Field for momentum spectrometry Vertical, +5 °, -5 ° wire orientation in drift chambers 90% Argon, 5% CO 2, 5% CH 4 gas mixture 150  m  m resolution depending on incident angle Typical single chamber efficiency of 97% (~90%) Current momentum resolution is ~150 MeV at 3GeV + -

Drift Chambers & Spectrometer Magnet

HARP Detector

Threshold Cerenkov Detector Filled with C 4 F 10 (perflourobutane) at atmospheric pressure. Discriminates between protons and pions at high momentum. At high beam momentum, strange particles (kaons) are also created. C 4 F 10 properties: n = pion threshold = 2.6 GeV/c kaon threshold = 9.3 GeV/c proton threshold = 17.6 GeV/c

HARP Detector

TOF Wall, Electron Identifier, Cosmic Trigger Wall, Beam Muon Identifier TOF Wall - plane of scintillator counters to discriminate between protons and pions at low momentum  t ~ 210 ps)   -  separation up to 4.6 GeV/c for  /p  2.4 GeV/c for  /K Electron Identifier - lead-scintillating fiber counters to discriminate between hadrons on the one hand, and photons and electrons on the other. Cosmic Trigger Wall - plane of scintillator sheets to trigger on cosmic muons for monitoring and calibration. Beam muon Identifier - iron-scintillator calorimeter to identify beam muons.

TPC TOF Cherenkov p/  separation at 4  level, “conservative” simplification P T vs. P L Box Plot for pion Production on Be

HARP Targets Beryllium Carbon Aluminum Copper Tin Titanium Lead } } Hydrogen Deuterium Nitrogen Oxygen solid targets 2%, 5%, 50%, 100% neutrino factory, MiniBooNE, K2K cryogenic targets atmospheric neutrino flux

MiniBooNE – HARP Project L. Coney, G. Mills, D. Schmitz, M. Sorel, R. Stefanski

● 1994 Began development of a FNAL Booster neutrino beam design and GEANT3 simulation code ● 1997 MiniBooNE/Booster beam proposal, with the realization that  /K cross sections were poorly understood (GEANT3/FLUKA) ● 2000 First discussions with HARP people on target calibration (Neutrino 2000, Sudbury, ON) ● GEANT/MARS code and new GEANT4 simulation code ● August 2002 Recorded >20 million 8.9 GeV proton triggers on several replica beryllium target configurations at the HARP experiment A little history…

The MiniBooNE Neutrino Beam Studies show that the largest uncertainty in the flux prediction is the knowledge of the  /K production cross sections Different models show up to a factor of 2-3 difference in neutrino rates in MiniBooNE!!  It is vital to calibrate the target in a proton beam   e ?

MiniBooNE Flux source of  source of e background 8 GeV p ++ K+K+ Be K +   0 + e + + e K 0 L   - + e + + e  e + +  + e  +   + + 

Enter HARP… PS214 at CERN (HARP) was designed to measure meson production over nearly 4  solid angle from 1.5 GeV/c to 24 GeV/c across a range of materials (H, D, Be, C, O, N, Al, Sn, Ta, Pb) At Neutrino 2000, MiniBooNE was approached by HARP and asked if MiniBooNE would like to us their apparatus October 2001: First run with 2% Be target at 8GeV/c August 2002 : MiniBooNE replica targets record >20 million triggers (5%, 50%, 100% )

MiniBooNE & HARP 1.3M events recorded in 2001 for 8 GeV protons on a 2% Be target In August, 2002, data was taken for a 5%, 50%, and 100%  Be target 2%5%50% MiniBooNE Target

Close-up of HARP Target Region

MiniBooNE Target

MiniBooNE replica targets:

GEANT4 geometry of Replica target:

Running conditions : Beam size : x,y RMS < 3 mm (target core diameter 9.5 mm) particles/spill events/spill (TPC readout Spills at Hz depending on PS operations Data taking over a period of 7 days In general, the system was stable, except one period of TPC problems

MiniBooNE Data Taking 2002 Target# of EventsComments 5% 6.77 M Empty thin target holder 0.58 M 50% 5.32 M Empty0.50 M Empty thick target holder  2.97 M Entire detector functional and in DAQ 100% 3.71 M (0.78 M) TPC out of DAQ or having problems

MiniBooNE Target Target as seen by the beam Events with an interaction divided by the beam profile (gaussian beam with  of 3mm) You can see where the beam is interacting in the target region. Target fins

Data Analysis: ● Reconstruction and calibration code under development (HARP collaboration) ● We are helping with the GEANT4 simulation and reconstruction code (Kalman filter for forward spectrometer)

MiniBooNErs at HARP in Action Dave and Michel

End of talk

Beam Profile on MiniBooNE Target

Hadron production cross sections, why do we care? Calculation requiring flux Want to measure this…

Flux calculation: Known very poorly! MC calculation

MiniBooNE and HARP Production Rates Decay Now Goal K +   0 + e + + e K 0 L   - + e + + e ~50% 5% ~100%10%  +  e + +  + e  +   + + 