Low-Energy -Nucleus Scattering Jorge G. Morfn Fermilab WIN03 8 October 2003 n-Nucleus Scattering Experiments 2 Time Line of Neutrino Studies 1960s - Have only low-energy s - Study properties of neutrinos - How many neutrinos are there? 1970s - Use low-energy neutrinos as a probe to study structure of the nucleon - structure of the weak current 1980s s - Increased energy and more massive detectors yield higher statistics and expanded kinematic range for nucleon structure studies 1990s s - Study properties of neutrinos - need low-energy s for this study - How many neutrinos are there? n-Nucleus Scattering Experiments 3 Whats covered by low-energy Nucleus interactions Cross sections of exclusive states. Bridging the gap from resonance to DIS. Nuclear Effects t x Bj -dependent nuclear effects (Shadowing, anti-shadowing, EMC-effect...) t Pauli suppression, t Nuclear Binding t Nuclear correlations, t Extended Fermi Gas model or Spectral Functions, t Hadron Formation Length and Nuclear transparency, t Final State Interactions. n-Nucleus Scattering Experiments 4 Steps ( not necessarily time-ordered ) in Low Energy -Nucleus Interactions Incoming neutrino imparts q (momentum and energy) via an IVB to a nucleus. Depending on x, q: t The interaction proceeds under shadowing, anti-shadowing or EMC effect. t the IVB interacts with the entire nucleus, 1 nucleon or with one or more quarks. For interactions with a nucleon, the target nucleon (off shell) carries initial p and E k within the nucleus. The (excited) A-1 nucleus recoils with -p and proceeds to a ground state via -emission or boil-off protons or other breakup mechanisms. A hadronic state is created (quasi-elastic, resonance, continuum, DIS). t Pauli Blocking influences final state nucleon momentum (quasi-elastic). The produced hadronic state proceeds through the nucleus. t Nuclear transparency, formation zone, and nuclear densities influence final state interactions. A visible final hadronic state and visible neutrino energy are recorded. n-Nucleus Scattering Experiments 5 Why do we care about low energy phenomena? E vis is not E - effect on the measurement of oscillation parameters Understanding backgrounds to ---> e NC resonant 1 0 production (direct or through nuclear effects) Coherent 1 0 production Observed hadronic state (particle type and kinematics) not necessarily the produced state ( ) interaction kinematics perturbed via nuclear effects t Quasi-elastic events lost or mimicked by resonance via nuclear effects n-Nucleus Scattering Experiments 6 How Important are Low-energy Neutrinos? Seeing the dip in the oscillation probability is a goal of MINOS VERY Difficult at low m 2. CC energy distributions have two important complications at low energy: Difference between E vis and E due to nuclear effects (particularly re-scattering, absorption). 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 - only as good as the input!. n-Nucleus Scattering Experiments 7 State of our Knowledge for these Steps The interaction proceeds under shadowing, anti-shadowing or EMC effect. Cant blindly use e/ - A results for - A since axial vector current participation t Evidence nuclear effects different - valence and sea quarks, theory hint of same for u & d t Use nuclear pdfs (Kumano or Eskola et al). For interactions with a nucleon, the target nucleon (off shell) carries initial p and E k within the nucleus. t Bodek-Ritchie extended Fermi-gas model invalid at high p F (NOMAD/CHORUS) t Use spectral functions (O. Benhar) - careful since some encompass EMC-effect A hadronic state is created (quasi-elastic, resonance, continuum, DIS). t Limited experimental data. For decades only --> N * by Rein-Sehgal from 70s, now Lee-Sato for +N --> + t From resonances to DIS: duality arguments and recent work by Bodek-Yang on low Q, high x pdfs The produced hadronic state proceeds through the nucleus. t Major stage in the process. Introduce very significant changes in the number and identity of hadrons (pion absorption and charge exchange) and total visible energy t Dual-parton Model with Formation Zone Intranuclear Cascade and Nuclear Transparencies n-Nucleus Scattering Experiments 8 Experimental Input - Make-up of T at low energy n-Nucleus Scattering Experiments 9 Just What Experimental Input is Available? Very complete and thoughtful analysis by: S. Zeller & E. Hawker and M. Sakuda D. Naples NuInt02 Sam Zeller NuInt02 Workshop on Neutrino-Nucleus Interactions in the Few GeV Region NuInt n-Nucleus Scattering Experiments 10 Coherent Pion Production 00 NN P Z n-Nucleus Scattering Experiments 11 Current/Future Experimental Investigations of these Topic Fermilab Booster Neutrino Beam - 8 GeV Protons t MninBooNe Experiment t FINeSE Experiment KEK Neutrino Beam - 12 GeV Protons t Original K2K Near Detectors t New SciBar Detector Fermilab NuMI Beam GeV Protons t MINERvA Experiment n-Nucleus Scattering Experiments 12 Fermilab Booster Neutrino Beam 8 GeV Protons MiniBooNe - H. Tanakas Presentation and discussions FINeSE - Fermilab Intense Neutrino Experiment n-Nucleus Scattering Experiments 13 Energy Spectrum and Channels Covered Peak Down by 1/10 n-Nucleus Scattering Experiments 14 FINeSE Detector Submit Proposal 12/03, if approved (and find $) start data-taking mid-06 n-Nucleus Scattering Experiments 15 FINeSE Physics Goals Measure contribution of strange quark to the spin of the proton - s Measure interaction cross-sections (40 % events QE) Extract nucleon form factors n-Nucleus Scattering Experiments 16 KEK Neutrino Beam Line 12 GeV Protons Peak Down by 1/10 n-Nucleus Scattering Experiments 17 K2K Original Front Detectors n-Nucleus Scattering Experiments 18 Results in addition to yesterdays 1 0 n-Nucleus Scattering Experiments 19 SciBar has been installed in summer 2003 Next Generation: New SciBar Detector n-Nucleus Scattering Experiments 20 Large Volume: (300300166) cm 3 ~15tons 10 ton fiducial volume Fine segmentation: 2.51.3cm Particle ID: p/ : dE/dx / : range #channels : ~15,000 Proton Momentum: by dE/dx and the range The SciBar Detector Fully Active Statistics 45,000 events (12,000 QE) / 3 x POT n-Nucleus Scattering Experiments 21 SciBar Physics Motivation Precise measurements of the neutrino-nucleus cross section around ~1GeV energy region. CC Quasi-elastic scattering ( + n + p) We will have a higher efficiency with a proton detection than other K2K Near detectors. CC-1 (resonant) production cross section. ( + n + p) With the precise measurement, will also use this mode to reconstruct the neutrino energy with the charged since it goes though the Delta resonance. Deep inelastic scattering ( + n + p ) Which the Bodek and Yang modification is correct or not at the K2K energy? Coherent Nuclear interaction (CC: + A +A, NC: + A +A) No measurement at this energy region so far. test theoretical models Measure both CC and NC coherent cross section. Measure spectrum of e n-Nucleus Scattering Experiments 22 MINER A (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 A Near Detector Hall Experiment n-Nucleus Scattering Experiments 23 Fermilab NuMI Beamline Zoom-lens: Horn 1 fixed - target and Horn 2 moved NuMI: Neutrinos at Main Injector 120 GeV protons 1.9 second cycle time Single turn extraction (10 s) Beam: POT Late 2004 n-Nucleus Scattering Experiments 24 NuMI -energy Distributions and Event Rates in the Near Detector Hall With 2.5 x pot per year of NuMI running at start-up. le-configuration: Events- (E >0.35 GeV) E peak = 3.0 GeV, = 10.2 GeV, rate = 200 K events/ton - year. me-configuration: Events- E peak = 7.0 GeV, = 8.5 GeV, rate = 675 K events/ton - year s-me rate = 540 K events/ton - year. he-configuration: Events- E peak = 12.0 GeV, = 13.5 GeV, rate = 1575 K events/ton - year s-he rate = 1210 K events/ton - year. With E-907 at Fermilab to measure particle spectra from the NuMI target, expect to know neutrino flux to 3%. n-Nucleus Scattering Experiments 25 Parasitic Running: Event Energy Distribution MINOS oscillation experiment uses mainly le beam with shorter s-me and s-he runs for control and minimization of systematics. An example of a running cycle would be: t 12 months le beam t 3 months s-me beam t 1 month s-he beam Consider 2 such cycles (3 year run) with 2.5x10 20 protons/year: 860 K events/ton. = 10.5 GeV t DIS (W > 2 GeV, Q 2 > 1.0 GeV 2 ): 0.36 M events / ton t Quasi elastic: 0.14 M events / ton. Resonance + Transition: 0.36 M events / ton - 1 production: 0.15 M events / ton. Peak Down by 1/10 n-Nucleus Scattering Experiments 26 MINER A Detector: Basic Conceptual Design - Coordinator: K. McFarland Triangular (2-3 cm base x 1-2 cm height) scintillator (CH) strips with fiber readout. Fully Active ( int = 80 cm, X 0 = 44 cm) / alternate with C planes > and nuclear tgt. Favored Photo-sensor: MAPMT (M64 a la MINOS) Example fid. vol: (r =.8m L = 1.5 m): 3 tons pure plastic or 5 tons with graphite R = 1.5 m - p: =.45 GeV/c, =.51, K =.86, P = 1.2 R =.75 m - p: =.29 GeV/c, =.32, K =.62, P =.93 Nuclear targets: of C, Fe and Pb.- Surround fully active detector with em-calorimeter, hadron-calorimeter and magnetized -id / spectrometer Use MINOS near detector as forward identifier / spectrometer. Attempt to constrain detector size so can be moved to an off-axis position. n-Nucleus Scattering Experiments 27 Basic Conceptual Design : ( A. Bodek, D. Casper and G. Tzanakos) Overall dimensions and relative volumes currently being determined X U V VUX EM Calorimeter: 2 mm = 1.5 mm Pb and two 0.25 mm stainless on each side Magentized Hadron Cal + Id/spec. Coils - bottom sides only Active Scintillator / Graphite detector Downstream end: EM Calorimeter plus HadCal Fiducial Volume n-Nucleus Scattering Experiments 28 Event rates (2.5 x protons per year) MINOS Off-axisPrime User Prime User Parasitic Parasitic (3 years) (1 year, me- ) (1 year, he- ) (2 year, he - ) CH2.60 M2.10 M4.80 M 2.70 M C1.70 M1.40 M3.20 M 1.80 M Fe1.70 M1.40 M3.20 M 1.80 M Pb1.70 M1.40 M3.20 M 1.80 M LH M 0.35 M 0.20 M LD M 0.80 M 0.45 M Detector ( 3 ton CH, 2 ton A ): Event Rates; CC - E > 0.35 GeV n-Nucleus Scattering Experiments 29 Physics of the Proposal Quasi-elastic Reaction - MINOS 3 year run, 3 ton fid. Vol K events Precision measurement of E ) and d /dQ, constrain -beam systematics t Precision determination of F A t Study of nuclear effects and their A-dependence e.g. proton intra-nuclear rescattering Resonance Production ( , N*..) Exclusive channels K 1- events Precision measurement of and d /dQ for individual channels t Detailed comparison with dynamic models, comparison of electro- & photo production the resonance-DIS transition region -- duality Study of nuclear effects and their A-dependence e.g. 1 2 3 final states Nuclear Effects - > 1700 K events per nuclear target Measure and p multiplicities as a function of E and A : convolution of quark flavor- dependent nuclear effects and final-state intra-nuclear interactions t Measure NC/CC as a function of E H off different nuclei t Measure shadowing, anti-shadowing and EMC-effect as well as flavor-dependent nuclear effects and extract nuclear parton distributions n-Nucleus Scattering Experiments 30 Physics of the Proposal - continued Total Cross-section and Structure Functions K transition, > 1000 K DIS t Precision measurement of low-energy total cross-section t Understand resonance-DIS transition region - duality studies with neutrinos t Detailed study of high-x Bj region: extract pdfs and leading exponentials Coherent Pion Production K plastic plus nuclear targets Precision measurement of for NC and CC channels t Measurement of A-dependence t Comparison with theoretical models models MINER A and Oscillation Physics - MINER A measurements enable greater precision in measure of m, sin 2 23 in MINOS MINER A measurements fundamental for 13 in MINOS and off-axis experiments MINER A measurements as foundation for measurement of possible CP and CPT violations in the sector n-Nucleus Scattering Experiments 31 Physics of the Proposal - continued Strange and Charm Particle Production - Exclusive channel E ) precision measurements - importance for nucleon decay background studies. Hyperon Production yielding new measurements of CKM using t Exclusive charm production channels at charm threshold to constrain m c Generalized Parton Distributions - t Provide unique combinations of GPDs, not accessible in electron scattering (e.g. C-odd, or valence-only GPDs), to map out a precise 3-dimensional image of the nucleon t Provide better constraints on nucleon (nuclear) GPDs, leading to a more definitive determination of the orbital angular momentum carried by quarks and gluons in the nucleon (nucleus) t provide constraints on axial form factors, including transition nucleon --> N* form factors n-Nucleus Scattering Experiments 32 Summary Future of Low-Energy -Nucleus Scattering Studies Very Encouraging