Nu Fact 04 Osaka Japan WG 2 Summary

Nu. Fact 04 - Osaka, Japan WG 2 Summary - Part 2 Neutrino Scattering Physics Topics Conveners: Makoto Sakuda and Jorge G. Morfín

Presentations and Discussions Low energy neutrino interactions T. Sato (Osaka) Nuclear modification of valence quark distributions and its effects on Nu. Te. V sin^2 ? theta_W S. Kumano (Saga) DISCUSSION SESSION- WHAT IMPORTANT THEORETICAL QUESTIONS LEFT TO ANSWER Mini. BOONE scattering results H. A. Tanaka (Princeton) K 2 K scattering results M. Hasegawa (Kyoto) MINERv. A expected scattering results J. G. Morfin (FNAL) Tau production and decay via neutrino scattering K. Mawatari (Kobe) Study of strange quark in the nucleon with neutrino scattering T-A. Shibata (TIT) K 2 K NC pi 0 production S. Nakayama (ICRR) HARP result I. Kato (Kyoto) BNL E 910 result J. Link (Colombia) DISCUSSION SESSION - WHAT IMPORTANT NEUTRINO SCATTERING PHYSICS QUESTIONS ARE UNANSWERED? DISCUSSION SESSION - CAN SUPERBEAM OR NEUTRINO FACTORY ADDRESS 2 THE OPEN QUESTIONS?

Neutrino Oscillation: Requirements Dave Casper Neutrino energy resolution for CC interactions t t K 2 K/T 2 K: Quasi-elastic channel MINOS/NO A: Calorimetry (Evis E ) Understand Nuclear Effects t Visible energy to neutrino energy Control near/far beam flux and energy spectrum differences at few percent level Control background for e appearance signature at few per-mille level t K 2 K Beam e, CC, NC contributions Control neutrino/anti-neutrino systematics at 1 percent level for mass hierarchy and CP studies C. Walter, NUINT 02 NO A ( 13 near CHOOZ bound) Inverted Hierarchy Normal Hierarchy 3

Time Snapshot Assume following experiments complete… K 2 K t t Mini. Boo. Ne t t HARP, BNL E 910 Jlab High precision elastic scattering MINER A (Running parasitically to MINOS) t t HARP, BNL E 910 Jlab High precision elastic scattering HARP, BNL E 910, MIPP (E 907) Jlab High precision elastic scattering T 2 K-I (no input as to scattering physics expectations) 4

K 2 K Near Detectors EM rim lo ca e et 3 m Extruded scintillator (15 t) 3 m Multi-anode PMT (64 ch) r n E (Ge. V) 1. 7 m Wave-length shifting fiber Sci. Bar M. Hasegawa (Kyoto) Sci. Fi 5

Mini. Boo. NE H. Tanaka, (Princeton) 6

Brief Introduction to the MINER A Experiment (Main INjector Expe. Riment -A) A High-Statistics -Nucleus Scattering Experiment Using an On-Axis, Fine-grained Detector in the Nu. MI Beam Received Stage I Approval in April 7

Quantitative Study of Low-energy -Nucleus Interactions Both HEP and NP collaborators D. Drakoulakos, P. Stamoulis, G. Tzanakos, M. Zois University of Athens, Greece G. Blazey, M. A. C. Cummings, V. Rykalin Northern Illinois University, De. Kalb, Illinois D. Casper University of California, Irvine, California W. K. Brooks, A. Bruell, R. Ent, D. Gaskell, , W. Melnitchouk, S. Wood Jefferson Lab, Newport News, Virginia E. Paschos University of Dortmund, Germany D. Boehnlein, D. A. Harris, M. Kostin, J. G. Morfin, P. Shanahan, P. Spentzouris Fermi National Accelerator Laboratory, Batavia, Illinois M. E. Christy, W. Hinton, C. E. Keppel Hampton University, Hampton, Virginia R. Burnstein, A. Chakravorty, O. Kamaev, N. Solomey Illinois Institute of Technology, Chicago, Illinois S. Kulagin Institute for Nuclear Research, Moscow, Russia I. Niculescu. G. . Niculescu James Madison University, Harrisonburg, Virginia S. Boyd, D. Naples, V. Paolone University of Pittsburgh, Pennsylvania A. Bodek, H. Budd, J. Chvojka, P. de Babaro, S. Manly, K. Mc. Farland, I. C. Park, W. Sakumoto, R. Teng University of Rochester, New York R. Gilman, C. Glasshausser, X. Jiang, G. Kumbartzki, K. Mc. Cormick, R. Ransome Rutgers University, New Brunswick, New Jersey H. Gallagher, T. Kafka, W. A. Mann, W. Oliver Tufts University, Medford, Massachusetts J. Nelson William and Mary College, Williamsburg, Virginia Red = HEP, Blue = NP, Green = Theorist 8

The MINER A Detector OPTIONAL C, Fe and Pb Nuclear targets Active target of scintillator bars (6 t total, 3 - 5 t fiducial) - M 64 PMT Surrounded by calorimeters t t upstream calorimeters are Pb, Fe targets (~1 t each) magnetized side and downstream tracker/calorimeter 9

Location in Nu. MI Near Hall MINER A preferred running is as close as possible to MINOS, (without Muon Ranger), using MINOS as high energy muon spectrometer t If necessary, MINER A can run stand-alone elsewhere in the hall with the muon ranger 11

The Nu. MI Neutrino Beam Main injector: 120 Ge. V protons 1 km 110 m Move target only Move target and Second horn With E-907(MIPP) at Fermilab to measure particle spectra from the Nu. MI target, expect to know neutrino flux to 12 ≈ ± 3 -4 %.

MINER A will have the statistics to cover a wide variety of important physics topics Assume 9 x 1020 POT: MINOS chooses 7. 0 x 1020 in LE beam, 1. 2 x 1020 in s. ME and 0. 8 x 1020 in s. HE m Event Rates per fiducial ton Process CC NC Quasi-elastic 103 K 42 K Resonance 196 K 70 K Transition 210 K 65 K DIS 420 K 125 K Coherent 8. 4 K 4. 2 K TOTAL 940 K 305 K Typical Fiducial Volume = 3 -5 tons CH, 0. 6 ton C, ≈ 1 ton Fe and ≈ 1 ton Pb 3 - 4. 5 M events in CH 0. 5 M events in C 1 M events in Fe 1 M events in Pb Main Physics Topics with Expected Produced Statistics Quasi-elastic Resonance Production Coherent Pion Production Nuclear Effects s. T and Structure Functions Strange and Charm Particle Production Generalized Parton Distributions 300 K events off 3 tons CH 600 K total, 450 K 1 p 25 K CC / 12. 5 K NC C: 0. 6 M, Fe: 1 M and Pb: 1 M 2. 8 M total /1. 2 M DIS event > 60 K fully reconstructed events (few K events? ) 13

After initial (parasitic to MINOS) run could add a Liquid H 2/D 2(/O/Ar) Target NOT APPROVED FOR THIS Fid. vol: r = 80 cm. l = 150 cm. 350 K CC events in LH 2 800 K CC events in LD 2 per year he- running. Few events with E ≈ 1 Ge. V. Technically easy/inexpensive to build and operate. H_2/D_2 MINOS Near Planes of C, Fe, Pb For part of run Meeting safety specifications the major effort. 14

Neutrino Scattering Topics What will we know and not know at time snapshot? Quasi-elastic Resonance Production - 1 pi Resonance Production - npi, transition region - resonance to DIS Deep-Inelastic Scattering Coherent Pion Production Strange and Charm Particle Production Nuclear Effects s. T and Structure Functions t t s(x) and c(x) High-x parton distribution functions Spin-dependent parton distribution functions Generalized Parton Distributions 15

(Quasi)-elastic Dominant reaction up to ~1 Ge. V energy Essential for E measurement in K 2 K/T 2 K The “well-measured” reaction t t (88% purity) Uncertain to “only” 20% or so for neutrinos Worse in important threshold region and for anti-neutrinos Axial form-factor not accessible to electron scattering t Essential to modeling q 2 distribution Recoil proton reconstruction requires fine-grained design - impractical for oscillation detectors Recent work focuses on non-dipole form-factors, non-zero Gn. E measurements Mini. Boo. Ne K 2 K Sci. Bar 2 -ring QE (70% purity) 16

MINER A CC Quasi-Elastic Measurements Fully simulated analysis, including realistic detector simulation and reconstruction 17

CC Resonant Single-Pion Production Existing data inconsistent (factor 2 variations) Treatment of nuclear effects unclear Renewed theoretical interest t K 2 K S. Nakayama M. Hasegawa 0 Rein - Sehgal used for decades Sato-Uno-Lee Dynamical model gives a better fit to (poor) data 0 Mini. Boo. Ne H. Tanaka: 18

MINER A Resonance Production - D Total Cross-section and ds/d. Q 2 for the D++ assuming 50% detection efficiency Errors are statistical only DO NOT FORGET RADIATIVE DECAYS AS BACKGROUND TO m --> e s. T 19

Resonant Multi-pion Production and transition to DIS - Quark/Hadron Duality Recent JLAB data have revived interest in quark/hadron duality Bodek and Yang have shown that DIS cross-sections can be extended into the resonance regime, and match the “average” of the resonant cross-section We need more than just the “average” knowledge of the transition region - hills and valleys Beyond kinematic range of K 2 K and Mini. Boo. Ne. MINER A - 600 K events t Challenge to the resolution of MINER A? Bodek and Yang 20

DIS: Parton Distribution Functions What Can We Learn With All Six & Structure Functions? Using Leading order expressions: Does s = s and c = c over all x? If so. . . 21

Measuring Six Structure Functions for Maximal Information on PDF’s R = Rwhitlow Neutrino 1 year he-beam + y 2 FL Anti-Neutrino 2 years he-beam (1 -y)2 X = 0. 1 - 0. 125 Q 2 = 2 - 4 Ge. V 2 Kinematic cuts in (1 -y) not shown 22

Coherent Pion Production t. Characterized by a small energy transfer to the nucleus, forward going . NC ( 0 production) significant background for m -->. e oscillation search t. Data has not been precise enough to discriminate between several very different models. 0 Z P t. K 2 K, with their Sci. Bar detector, and Mini. Boo. Ne will attempt to explicitly measure this channel - important low E measurement N N t. Expect 25 K events and roughly (30 -40)% detection efficiency with MINER A. t. Can also study A-dependence with MINER A 23

MINER A: Coherent Pion Production 25 K CC / 12. 5 K NC events off C - 8. 3 K CC/ 4. 2 K NC off Fe and Pb Rein-Seghal Paschos. Kartavtsev MINER A Expected Mini. Boo. Ne and K 2 K measurements 24

Nuclear Effects - Final state interactions Include hadron formation length corrections E = 5 Ge. V + + LH on LH off NEUGEN K 2 K QE analysis MINER A can measure LH off of C, Fe and Pb 25

Nuclear Effects - modified interaction probabilities S. Kumano Fermi motion 1. 2 EMC NMC E 139 E 665 1. 1 1 valence-quark 0. 9 original 0. 8 shadowing 0. 7 0. 001 0. 01 sea quark antiquark EMC finding x 0. 1 valence quark EXPECTED to be different for !! 1 26

Nuclear Effects - Low , low Q 2 shadowing Q 2 distribution for Sci. Bar detector Problem has existed for over two years Larger than expected rollover at low Q 2 Mini. Boo. NE From J. Raaf (NOON 04) All “known” nuclear effects taken into account: Pauli suppression, Fermi Motion, Final State Interactions They have not included low- shadowing that is only allowed with axial-vector (Boris Kopeliovich at Nu. Int 04) Lc = 2 / (m 2 + Q 2) ≥ RA (not m. A 2) Lc 100 times shorter with m allowing low -low Q 2 shadowing ONLY MEASURABLE VIA NEUTRINO - NUCLEUS INTERACTIONS! MINER A WILL MEASURE THIS ACROSS A WIDE AND Q 2 RANGE WITH C : Fe : Pb 27

Low Q 2 Suppression - alternative considerations M. Sakuda List of items to be considered Is Coherent pion suppressed? t t K 2 K will use PID to disentangle 1 /coherent pion (Hasegawa) New data (e-N, g-C) on coherent pion production. g. C 0 C from Mainz MAMI Accelerator may tell us something. Change in Elastic form factors t Cause A few % effect on ds/dq 2 in lowq 2 region ND form factor coupled with MA t t Sato (Nufact 04), Paschos (Nu. Int 04) Old Rein-Sehgal ND form factor does not agee with data. Uniform Fermi momentum distributions in MC? t Electron scattering data show large kf component. Benhar(Nu. Int 04) and Nakamura (Nu. Int 04). QE peak cross section 10 -20% higher with Fermi Gas than with Spectral Functions which agrees better with electroproduction data, . 28

What will we need beyond Mini. Boo. Ne, K 2 K and MINER A parasitic run for neutrino scattering? ANTINEUTRINO EXPOSURE t HYDROGEN AND DEUTERIUM EXPOSURE FOR and t Need reasonable event rates at E ≈ 1 GEV NARROW BAND BEAM FOR DETAILED LOOK AT NC? t Need to improve purity - Nu. Fact 05 design efficient beam (with plug) Nu. Fact 05 - Is off-axis beam sufficiently narrow? IMPROVED DETECTOR TECHNIQUES t PARTICULARLY GOOD NEUTRON DETECTION FOR 29

What can Superbeams and Neutrino Factories Add to Scattering Measurements? Debbie Harris Neutral Current Measurements vs E Anti-neutrino cross sections & interactions H 2, D 2 Measurements Polarized Target Measurements (spin structure functions) Narrow Band Beams t How narrow is narrow? t Are there tricks to get more narrow beams? Broad Band Beams t Largest rate t No NC vs E available Beta-beams t Broad band, Low Energy Neutrino Factories t Broad Band t Neutrino and antineutrino at the same time, if you can reconstruct m and e CC t NO NC vs E or even vs neutrino 30 helicity!

Summary At the completion of Mini. Boo. Ne, K 2 K and the MINER A parasitic run we will have reasonable results for neutrino-nucleus interactions including cross-sections, form factors and nuclear effects. We will need a Super. Beam to have similarly reasonable results for cross-sections, hydrogen and deuterium cross-sections for both and , high-statistics narrow-band studies of NC (and CC) channels. We will need a Neutrino Factory for neutrino-polarized target experiments (T-A. Shibata) to understand the spin-dependent pdfs and generalized parton distributions. 31