MINERνA (Main INjector ExpeRiment v-A) A High-Statistics Neutrino Scattering Experiment Using an On-Axis, Fine-grained Detector in the NuMI Beam Argonne - Athens - California/Irvine - Colorado - Dortmund - Duke - Fermilab - Hampton - I I T - INR/Moscow -James Madison - Jefferson Lab Minnesota - Pittsburgh - Rochester - Rutgers - South Carolina - Tufts 18 Groups: Red = HEP, Blue = NP, Green = Theorists only Jorge G. Morfín - Fermilab CERN 17 September 2003 Neutrino Scattering in the NuMI Beam 1 52 Collaborators (so far…) S. Kulagin J.Arrington, D.H.Potterveld, P.E.Reimer Institute of Nuclear Research, Moscow, Russia Argonne National Laboratory, Argonne, Illinois C.Andreopoulos, G.Mavromanolakis, P.Stamoulis, I.Niculescu N.Saoulidou, G.Tzanakos, M.Zois James Madison University, Harrisonburg, Virginia University of Athens, Athens, Greece A.Bruell, R. Carlini, R.Ent, D.Gaskell, J. Gomez, C.E.Keppel. D.Casper W.Melnitchouk, S.Wood University of California, Irvine, California Jefferson Lab, Newport News, Virginia E.R.Kinney M.DuVernois University of Colorado, Boulder, Colorado University of Minnesota, Minneapolis, Minnesota E. Paschos S. Boyd, D. Naples, V. Paolone University of Dortmund, Dortmund, Germany University of Pittsburgh, Pittsburgh, Pennsylvania D.Dutta A.Bodek, H. Budd, P. de Babaro, G. Ginther, S, Manly, Duke University, Durham, North Carolina K. McFarland, W. Sakumoto, P. Slattery, M. Zielinsky University of Rochester, Rochester, New York D.Harris, M. Kostin, J.G.Morfin, P.Shanahan Fermi National Accelerator Laboratory, Batavia, Illinois R.Gilman, C.Glasshausser, R.Ransome Rutgers University, New Brunswick, New Jersey M.E.Christy Hampton University, Hampton, Virginia T.Bergfeld, A.Godley, S.R.Mishra, C.Rosenfeld University of South Carolina, Columbia, South Carolina N.Solomey Illinois Institute of Technology, Chicago, Illinois H.Gallagher, W.A.Mann Tufts University, Medford, Massachusetts Neutrino Scattering in the NuMI Beam 2 For more information… For more details than time this morning allows - Salle B 14:00 Neutrino Scattering in the NuMI Beam 3 MOTIVATION Why, after nearly 40 years of accelerator ν experimentation, as we are pushing the energy frontier, are we still interested in lower energy ν scattering physics? Neutrino Scattering in the NuMI Beam 4 NuMI Beamline on the Fermilab Site Neutrino Scattering in the NuMI Beam 5 NuMI Facility / MINOS Experiment at Fermilab Precision examination of atmospheric ν anomaly Energy distribution of oscillations Measurement of oscillation parameters Participation of neutrino flavors Direct measurement of ν vs ν oscillation Magnetized far detector: atm. ν’s. Likely eventual measurement with beam Near Detector Far Detector: 5400 tons. NuMI: Neutrinos at Main Injector 980 tons O(2Kevts/year) Finished! 120 GeV protons Det. 2 1.9 second cycle time Single turn extraction (10µs) Det. 1 Beam: POT Late 2004 Neutrino Scattering in the NuMI Beam 6 NuMI Beamline Geometry Target-Horn Chase: 2 parabolic horns. 50 m Decay Region: 1m radius decay pipe. 675 m Hadron Absorber: Steel with Al core 5 m Muon range-out: dolomite (rock). 240 m Near Detector Hall 45 m Neutrino Scattering in the NuMI Beam 7 NuMI Neutrino Beam (zoom-lens) Configurations Horn 1 position fixed - move target and horn 2 to change mean energy of beam. Three “nominal” configurations: low-, medium-, high energy. In addition, “semi-me” and “semi-he” beams. Horns left in le configuration and only target moved. Neutrino Scattering in the NuMI Beam 8 NuMI Neutrino Spectrum νµ CC Events/kt/year Use LOW ENERGY Beam Neutrino Scattering in the NuMI Beam 9 How Important are Low-energy Neutrinos? Seeing the “dip” in the oscillation probability is a goal of MINOS VERY Difficult at low ∆m2. • CC energy distributions have two important complications at low energy: • Difference between Evis and Eν due to nuclear effects (particularly re-scattering). • A required subtraction of NC events that fake low energy CC. • In both cases MINOS, as well as all other oscillation experiments, will have to rely on MC. Neutrino Scattering in the NuMI Beam 10 Next Generation: NuMI Off-axis Experiment The dominant oscillation parameters will be known reasonably well from solar/reactor ν and from SuperK, K2K, MINOS, CNGS The physics issues to be investigated are clearly delineated: θ θ Need measurement of missing oscillation probability ( 13 = µe) ∆ Need determination of mass hierarchy (sign of m13) Search for CP violation in neutrino sector Measurement of CP violation parameters (Testing CPT with high precision) ν ν Above can be accomplished with the µ ⇒ e transition. How do we measure this sub-dominant oscillation? θ 13 small (≤ 0.1) - maximize flux at the desired energy (near oscillation max) Minimize backgrounds - narrow energy spectrum around desired energy One wants to be below τ threshold to measure subdominant oscillation Neutrino Scattering in the NuMI Beam 11 The Off-axis Solution More flux than low energy on- axis (broader spectrum of pions contributing) No nasty high-energy tail, which contributes so much background! Neutrino event spectra at a detector located at different transverse locations Neutrino Scattering in the NuMI Beam 12 Motivation: Current/Future ν Oscillation Experiments ν use a Few GeV on a C, O2,Fe or ??? Nucleus MINOS: Neutrino Beam NuMI Off-axis Neutrino Beam We need to understand low energy ν-Nucleus interactions for oscillation experiments! Neutrino Scattering in the NuMI Beam 13 Motivation: Exclusive Cross-sections at Low Energies - Quasi-elastic: DISMAL No one ever lost money by betting against neutrino experiments being correct. -- Don Perkins World sample statistics is still fairly miserable! Cross-section important for understanding low-energy atmospheric neutrino oscillation results. Needed for all low energy neutrino monte carlos. “K2K near detector data on water was fit with wrong vector form factors. New (Budd, Bodek, Arrington ) BBA2003 form factors and updated MA have a significant effect on Neutrino oscillations Results.” Quote from Arie Bodek Neutrino Scattering in the NuMI Beam 14 Motivation: Exclusive Cross-sections at Low Energies - 1-Pion and Strange Particle: DISMAL CC World’s sample of NC 1-π ANL ν p→ν n π+ (7 events) νp→µ–pπ+ ν n→ν n π0 (7 events) Gargamelle ν p→ν p π0 (240 evts) ν n→ν n π0 (31 evts) K2K Starting a careful analysis of single π0 production. νn→µ–pπ0 Strange Particle Production Gargamelle-PS - 15 Λ events. FNAL - ≈ 100 events ZGS - 7 events ν →µ– π+ n n BNL - 8 events Larger NOMAD sample expected Neutrino Scattering in the NuMI Beam 15 σ How about Tot? Low energy (< 10 GeV) primarily from the 70’s and 80’s suffering from low statistics and large systematics (mainly from ν flux measurements). Mainly bubble chamber results --> larger correction for missing neutrals. σ How well do we model Tot? D. Naples - NuInt02 Neutrino Scattering in the NuMI Beam 16 Motivation: Knowledge of Nuclear Effects with Neutrinos: essentially NON-EXISTENT Anti-shadowing Fermi motion “EMC” effect Shadowing µ ν− Α F2 / nucleon changes as a function of A. Measured (with high statistics) in -A not in Good reason to consider nuclear effects DIFFERENT in ν -A. Presence of axial- vector current. SPECULATION: Much stronger shadowing for ν -A but somewhat weaker “EMC” effect? Different nuclear effects for valance and sea --> different shadowing for xF3 compared to F2? Different nuclear effects for d and u quarks? 2Θ NUCLEAR EFFECTS EXPLAIN SOME/ALL OF THE NuTeV SIN W RESULT? LET’S MEASURE NC/CC AND NUCLEAR EFFECTS WITH ν − Α1, Α2 , Α3 ... Neutrino Scattering in the NuMI Beam 17 Motivation: Nuclear Effects A Difference in Nuclear Effects of Valence and Sea Quarks? Nuclear effects similar in Drell-Yan and DIS for x < 0.1. Then no “anti-shadowing” in D-Y while “anti-shadowing” seen in DIS (5-8% effect in NMC). Indication of difference in nuclear effects between valence & sea quarks? This quantified via Nuclear Parton Distribution Functions: K.J. Eskola et al and S. Kumano et al Neutrino Scattering in the NuMI Beam 18 Motivation: Nuclear Effects A Specific Look at ν Scattering Nuclear Effects: Shadowing ν •S.A.Kulagin has calculated shadowing for F2 and xF3 in -A interactions. Stronger effect than for µ-A interactions •Shadowing in the low Q2 (A/VMD dominance) region is much stronger than at higher Q2. •Major difference between Kulagin and Kumano predictions µ-Ca/µ-D Kumano Neutrino Scattering in the NuMI Beam 19 Experimental Results in ν Scattering: Nuclear Effects? Bubble Chamber: Ne/D2 FNAL E-545 Where is the “EMC” effect? CERN BEBC Neutrino Scattering in the NuMI Beam 20 Motivation: Comparison of ν-A with JLab results on e-A; high xBj pdf Particular interest in the high -xBj region where there seems to be a discrepancy between global fits and data. Study of structure functions off various nuclear targets, again at high- xBj, allows comparison with nuclear structure models where sensitivity is the greatest. Close examination of the non-PQCD and pQCD transition region, in context of quark-hadron duality, with axial-vector probe. CTEQ working group in association with C. Keppel (Jlab) formed to investigate high -xBj region. Neutrino Scattering in the NuMI Beam 21 Motivation: High xBj parton distributions How well do we know quarks at high-x? Wu-Ki Tung Ratio of CTEQ5M (solid) and MRST2001 (dotted) to CTEQ6 for the u and d quarks at Q2 = 10 GeV2. The shaded green envelopes demonstrate the range of possible distributions from the CTEQ6 error analysis. Neutrino Scattering in the NuMI Beam 22 We have the Motivation. Can we perform the experiment? Neutrino Event Energy Distributions and Statistics in the NuMI Near Hall Reasonably expect 2.5 x 1020 pot per year of NuMI running at start-up. le-configuration: Events- (Eµ >0.35 GeV) Epeak = 3.0 GeV, <Eν> = 10.2 GeV, rate = 200 K events/ton - year.