HARP a hadron production experiment. Emilio Radicioni, INFN for the HARP collaboration

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1 HARP a hadron production experiment Emilio Radicioni, INFN for the HARP collaboration

2 HARP motivations provide data for neutrino factory / muon collider design. reduce the uncertainties in the atmospheric neutrino flux calculations get better prediction of neutrino fluxes for K2K and MiniBooNE provide a calibration sample for hadron generators in MonteCarlo simulation packages on this last issue we are collaborating with GEANT4 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 2

3 revival of hadron production experiments understanding ν-beam targets, atmospheric ν fluxes and the detailed composition of ν beams relies on knowledge of the hadron production processes. hadron generators (which are in a way or another - all tuned to existing data) show 30% to 100% discrepancy in their predictions calibration of hadron generators, apart from the issue of neutrino physics, is essential for any kind of detailed simulation study Available data is limited, either by statistics (bubble chamber or emulsion experiments), by lack good π to p separation, or by acceptance Abbott et al: p-be 14.6 GeV/c Lundy et al: p-be 12.5 GeV/c Allaby et al: p-be 19.2 GeV/c 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 3

4 revival of hadron production experiments Some data could be already exploited: BNL E910 main goal: Strageness production in p-a collision (comparison with A-A collisions) Some data overlap with our needs 6,12,18 GeV/c beam proton momenta Be,Cu,Au targets however low statistics in general, very low at 6GeV/c no thick targets no backward acceptance (target outside the TPC) 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 4

5 I- optimizing the ν-factory design Primary energy, target material and geometry, collection scheme maximizing the π +,π production rate /proton /GeV knowing with high precision (<5%) the P T distribution CERN scenario: 2.2 GeV/c proton linac. Phase rotation longitudinally freeze the beam: slow down earlier particles, accelerate later ones need good knowledge also of P L distribution 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 5

6 II- Atmospheric neutrino fluxes π µ N 2,O 2 + primary flux π ν µ ν µ K p decay chains hadron production... 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 e ν e 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 6

7 Discrepancies between hadronic generators G.Battistoni, Now /03/2002 E.Radicioni - XXXVII Rencontres de Moriond 7

8 III- Measurements of experimental targets precise understanding of a ν beam spectrum and composition requires hadroproduction data for 2 main reasons: to calibrate the hadron generators for a particular primary beamenergy and a particular target material. This is achieved by measuring π and K production cross section on thin targets to be able to reproduce the effect of re-interactions in the target. This is achieved by measuring the cross sections with several targets of different interaction lenght HARP is measuring Al targets (0.02λ, 0.5λ, 1λ, + K2K replica) at 12.9GeV/c Be targets (0.02λ, 0.5λ, 1λ, + MiniBooNE replica) at 8Gev/c 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 8

9 HARP secondary hadron yields for different beam momenta as a function of momentum and angle of daughter particles for different daughter particles as close as possible to full acceptance the aim is to provide measurements with about 2% overall precision efficiencies must be kept under control, down to the level of 1% primarily trough the use of redundancy from one detector to another thin, thick and cryogenic targets T9 secondary beam line on the CERN PS allows a 2 15 GeV energy range 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 9

10 Large event sample HARP O(10 6 ) events per setting a setting is defined by a combination of target type and material, beam energy and polarity Fast readout aim at 10 3 events/ps spill, one spill=400ms. Event rate 2.5KHz corresponds to some 10 6 events/day very demanding (unprecedented!) for the TPC. mesurements are needed NOW re-use existing detectors as much as possible cost effectiveness minimize effort and time-scale 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 10

Flight dipole magnet cerenkov target, Inner Trigger Cylinder, TPC

11 Experimental area & detector layout electron identifier Drift chamber stations Forward Trigger Plane muon identifier Time Of Flight dipole magnet cerenkov target, Inner Trigger Cylinder, TPC and RPC in a solenoid magnet 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 11

12 Acceptances TPC Forward spectrometer 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 12

13 Acceptances Acceptance: P T vs P L box plot for pions produced in 15GeV/c interactions of protons on thin Be target redundancy in overlap regions 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 13

Targets Solid targets target Z Be 4 C 6 thin (cm) 0.81 0.76 thick (cm) 38 Al 13 0.79 Cu 29 0.

34 Cryogenic targets 6 cm long H 2 D 2 N 2 O 2 target tube and standard target holder Special

14 Targets Solid targets target Z Be 4 C 6 thin (cm) thick (cm) 38 Al Cu Sn Ta Pb Cryogenic targets 6 cm long H 2 D 2 N 2 O 2 target tube and standard target holder Special targets K2K target MiniBooNE target ~60 cm Al ~65 cm Be special cryogenic target holder 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 14

15 Large-angle detectors: TPC+RPC beam ITC inner trigger cylinder target 2.24 m TPC pad plane/readout 1.59 m solenoid coil TPC field cage RPC barrel 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 15

Large-angle detectors: RPC Motivation separation of large-angle e/π below 300MeV/c < 200ps needed resolution not achievable with one-sided readout scintillators

16 Large-angle detectors: RPC Motivation separation of large-angle e/π below 300MeV/c < 200ps needed resolution not achievable with one-sided readout scintillators (2-sided impossible for mechanical resons). preliminary 30 barrel RPCs, 16 forward 150 ps resolution 99% efficiency 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 16

17 Large-angle detectors: TPC 1.5m long, 0.8m diameter 0.7T solenoidal magnetic field 12Kv/m electric field makes the ionization drift to the readout plane with a speed of 5cm/µs about 30µs total drift time about 4000 readout pads arranged in 20 concentric rows ionization level is sampled on each pad in 0.1µs time bins formidable amount of data online zero-suppression + fast readout construction: Aleph s TPC90 magnet design inspired by existing detectors or designs (Aleph, NA49, Alice) readout from Alice/NA45 preliminary studies ITC RPC (courtesy M.C. Morone, A. Grossheim) 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 17

18 forward spectrometer: drift chambers 0.68T dipole magnet for tracking and momentum measurements in the forward region DCs from NOMAD, but equipped with new readout electronics (TDCs) for faster readout DC modules arranged in 4 stations. 1 module = 4x3planes = 4x(-5,0,+5 ) total of 60 DC planes, 42 wires/plane ( 3k channels) Average hit efficiency 91%, compensate by redundancy in number of planes. Reduced efficiency w.r.t. NOMAD due to different gas mixture (safety constraints) 3m 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 18

19 forward spectrometer: CERENKOV Cylindrical mirrors in a 35 m 3 vessel filled with C 4 F 10 Threshold cerenkov to complement the TOF in the higher energy region mirrors and mechanical construction are new 8-inch photomultipliers are recovered from CHOOZ Calibration and efficiency studies are in progress preliminary 3 GeV 5 GeV 12 GeV Eff pions Eff muons 89. ± 10. % 97.5 ± 10. % C.L. (113/113) 95% C.L. (40/40) /03/2002 E.Radicioni - XXXVII Rencontres de Moriond 19

20 forward spectrometer: TOF 2.5 m preliminary ~7.4 m time separation for 3GeV beam particles (π,p) overall stability has been continuously verified with cosmic-ray events and laser calibration 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 20

21 forward spectrometer: e-id purpose: separate e from π, as cross-check with the cerenkov made by one plane of 62 calorimeter modules 5λ thick (EM1) + one plane of 80 modules 11λ thick (EM2) recovered from the CHORUS Pb/scint. fiber calorimeter Detailed calibration and e/ π separation studies are under way preliminary 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 21

22 forward spectrometer: beam-µ catcher electron identifier 3.3 m Electron identifier: Pb/fibre: 4/1 62 EM modules, 4 cm thick 80 HAD1 modules, 8 cm thick Muon identifier: Iron + scintillator slabs Thickness 6.44 λ I 6.72 m muon identifier 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 22

23 less than one year before 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 23

24 View of the experimental area 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 24

25 Blow-up of the target region 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 25

26 a (not) very typical event 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 26

27 Collected data sample HARP has collected about 100 millions physics triggers thin Be, Al, Ta, Pb targets at 3, 5, 12 and 15 GeV/c, positive and negative polarities thick Ta and Pb target at +3 GeV/c some K2K target measurements at GeV/c some MiniBooNE target measurements at +8 GeV/c emtpy target runs for background studies copper button target runs to assess the ability to reconstruct the shape of the target + cosmics, and various types of calibration events 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 27

28 Present status of the analysis low energy (3GeV/c) beam particle composition and contaminations large angle (all angles covered by the barrel-rpcs) RPC calibration and time resolution TPC calibration and equalization TPC clustering TPC track finding and fitting particle ID (e,π,k,p) will try to have the first dn/dpdη with an error of the order of 5% by end of March /03/2002 E.Radicioni - XXXVII Rencontres de Moriond 28

29 Perspectives for 2002 data taking Exploiting the shutdown for understanding the detector and improving the calibration the PS beam will restart in May cryogenic targets (H 2, D 2, N 2, O 2 ) final K2K and MiniBooNE statistics complete the measurement on standard targets with all beam momenta and both polarities 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 29

30 Follow-up complement the HARP measurements with higher momenta relevant for higher energy ν-fact proton drivers higher energy region of hadroproduction for atmospheric neutrino studies study the beam composition of higher-energy traditional beams, like the NuMI beam (120GeV/c) or the proposed JHF super-beam (50GeV/c proton driver) the HARP community has proposed to use the NA49 apparatus at CERN for this purpose. NA49 has been built for detailed studies of particle production in Pb-Pb collisions at high energies It may be used as-is for our purposes An interesting option is given by the fact that E907 at FNAL is getting momentum from Livermore joining the effort. E907 has plans for a wide range of measurements, among which relevant ones for neutrino physics 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 30

tracking chambers rate somehow limited (optimized for VERY high multiplicity events).

31 Follow-up: HARP/NA49? particle ID in the TPC is augmented by TOFs leading particles are identified as p or n by a calorimeter in connection with tracking chambers rate somehow limited (optimized for VERY high multiplicity events). order 10 6 event per week is achievable NA49 is located on the H2 fixed-target station on the CERN SPS. secondary beams of identified π,k,p; 40 to 350 GeV/c momentum Relevant for atmospheric neutrinos and NuMI beam 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 31

Follow-up: E907 @ FNAL proposed on the FNAL main injector, seconday beams of π,k,p; 5 to 120 GeV/c In addition to tests of scaling lows in high-energy particle production, nuclear and heavy-ions

32 Follow-up: FNAL proposed on the FNAL main injector, seconday beams of π,k,p; 5 to 120 GeV/c In addition to tests of scaling lows in high-energy particle production, nuclear and heavy-ions physics, E907 is relevant for atmospheric neutrinos, NuMI beam, higher-energy proton drivers for ν-factories As in all of the previous cases, it is an open-geometry spectrometer. TPC+spectrometer, complemented with TOFs and ring-imaging Cerenkov aiming at the same precision level as HARP: 2% Planning for data points with statistics of events. One data point would take about 6 days. 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 32

33 Conclusions HARP has successfully completed the first round of data taking Data are being analysed, first results will soon be available The desired data sample will be completed in 2002 Already proposed experiments will extend HARP s measurements to higher energies 12/03/2002 E.Radicioni - XXXVII Rencontres de Moriond 33

Hadron Production cross-sections

23/06/2005 E.Radicioni - NuFact2005 1 Hadron Production cross-sections Emilio Radicioni INFN-Bari NuFact05 21-26/06/2005 23/06/2005 E.Radicioni - NuFact2005 2 Motivations Past experiment Present experiment