NuFact04 - Osaka, Japan

1. NuFact04 - Osaka, Japan WG2 Summary - Part 1 Neutrino Scattering Physics Topics Conveners: Makoto Sakuda and Jorge G. Morfín

2. Hadron production cross section p + A (Be,C,Al,Fe) p+- + X • Previous neutrino cross sections in the few GeV region are published using only 100-1000 events and using the old hadron production cross sections with 10-20% errors. K2K/MiniBOONE have >10K-100K events. • This is a fundamental input to not only neutrino beam and atmospheric neutrino flux calculations but also any detector simulators. • We need better accuracy at a few % (<10%). D.Casper (Prenary talk on July 30) s(En) =N(En)/(F(En) nTarget)

3. K2K/MiniBOONE have enough statistics to measure cross sections. All they need is flux. K2K MiniBOONE SciBar (Carbon) 1-track SciBar (Carbon) 2-track K2K SciFi (Water) has QE. KT (Water) NCp0

4. WG2 July 31 New experiments (BNL-E910, HARP, MIPP) on hadron production • HARP measurements of pion yieldfor neutrino experiments I.Kato (Kyoto) 2. Pion Production on Be at 6, 12 and 18 GeV in Brookhaven E910 -- J.Link (Columbia)

5. I.Kato HARP Detectors T9 beam Large angle tracks (inside solenoid) TPC: Tracking & PID RPC: PID Forward Particle ID TOF wall: PID for 0–4.5 GeV/c Cherenkov: PID for 3–15 GeV/c EM calorimeter: e/p separation Beam Detectors Beam Cherenkov: p/p/K separation Beam TOF: p/p/K separation MWPC: Beam direction Forward tracking NOMAD drift chambers: Dipole magnet: Tracking & Momentum analysis Used for Forward Analysis

6. I.Kato Pion yield: K2K thin target 5%l Al target (20mm) Use K2K thin target (5%l) • To study primary p-Al interaction • To avoid absorption / secondary interactions K2K replica (650mm) p > 0.2 GeV/c |y | < 50 mrad 25 < |x| < 200 mrad Raw data 2 4 6 8 10 -200 -100 0 100 200 0 qx(mrad) P(GeV/c) p-e/p misidentification background

7. Pion yield After all correction 5% l Al target p > 0.2 GeV/c |y | < 50 mrad 25 < |x| < 200 mrad 6 10 2 4 0 8 -200 -100 0 100 200 P(GeV/c) qx(mrad) • Systematics are still to be evaluated: • tracking efficiency knownat 5% level • expect small effect from PID

8. Brookhaven Experiment 910 J.Link E910 used a spectrometer with good acceptance and particle ID over the momentum and angular range of interest to MiniBooNE. Particle ID from dE/dx in the TPC, threshold Čerenkov, and Time of Flight.

9. E910 cross section and Sanford-Wang Fit Results J.Link 6.4 GeV/c 12.3 GeV/c Preliminary Preliminary

10. E910 cross section and Sanford-Wang Fit Results J.Link 17.6 GeV/c Preliminary

11. Comparison to Earlier Data J.Link The measured π+ cross section is similar to that measured by past experiments. Current Analysis Cho, et al., 1971 The spectrum is a little softer and the flux normalization is slightly higher at 8.9 GeV/c Still, the production spectrum is in agreement with the old fits to within errors. (>10% in total ν flux) Preliminary

12. Cho et al., 1971, p+Be at 12 GeV, ds/dWdp at qp=0,2,4,6,8,10,12 deg.

13. Summary • HARP pion yield (arbitrary units) for K2K thin Al target (20mm) are available for p > 0.2 GeV/c, |y | < 50 mrad, 25 < |x| < 200 mrad. Systematics are still to be evaluated. • BNL E910 has presented a preliminary p+ cross section at 6.4,12.3 and 17.6 GeV. Comparison with Sanford-Wang fit and the previous measurements shows agreement at 10% or so. Some difference at forward angle and <3 GeV region exists. Systematic errors are being studied. • K2K/MiniBOONE wait for the publication.