1. Neutrino Studies at an EIC Proton Injector Jeff Nelson College of William & Mary

2. EIC2 3/04 Page 2 Outline A highly selective neutrino primer >Including oscillations (what & why we believe) Neutrino sources (now & future) >Beams >Example concepts & proposals for next decade and beyond What will we be studying in 10+ years? >Summary of yesterday’s neutrino session >Short baseline Neutrino properties Neutrinos interactions and neutrinos as probes >Long baseline – oscillation physics >Novel beams Where an EIC proton injector could fit into this future

3. EIC2 3/04 Page 3 Cliffs Notes on Neutrinos There are only 3 “light” active neutrino flavors (from Z width) >Electron, muon, & tau types >Cosmological mass limits imply ∑m ν < 0.7 eV (WMAP + Ly-a) >Oscillations imply at least one neutrino greater than 0.04 eV (more later) Basic interactions => basic signatures >Cross sections crudely linear with energy >Charged current (CC) The produced lepton tags the neutrino type Has an energy threshold Neutrino’s energy converted to “visible” energy >Neutral current (NC) No information about the neutrino type No energy threshold Some energy carried away by an out-going neutrino >Electron scattering (ES)

4. EIC2 3/04 Page 4 With 2 neutrino basis (weak force & mass) there can be flavor oscillations The probability that a neutrino (e.g.   ) will look like another variety (e.g.  ) will be P(    ; t)  = | | 2 A 2-component unitary admixture characterized by  results in P(    ) = sin 2 2  sin 2 (1.27  m 2 L/E) Experimental parameter L (km) /E (GeV) Oscillation (physics) parameters sin 2 2  (mixing angle)  m 2 = m  2 - m  2 (mass squared difference, eV 2 ) E (GeV) 0.0 1.0 012345678910 P(v    ) Oscillation Formalism  m 2 = 0.003 eV 2 ; L = 735 km

5. EIC2 3/04 Page 5 3-Flavor Oscillation Formalism In 3 generations, the mixing is given by >Where, and >There are 3  m 2 ’s (only 2 are independent) > 2 independent signs of the mass differences >There are also 3 angles and 1 CP violating phase Predicts: CPV, sub-dominate oscillations (all 3 flavors) Matter effects (MSW) >Electron neutrinos see a different potential due to electrons in matter

6. EIC2 3/04 Page 6 How do we know what we know? In the past decades there have been many oscillation experiments in many forms Neutrino sources >Reactor neutrinos >Solar neutrinos >Supernovae >Atmospheric neutrinos (cosmic rays) >Heavy elements concentrated in the Earth’s core >Accelerator neutrinos Luckily we are converging to just a few important facts…

7. EIC2 3/04 Page 7 Sun emits neutrinos while converting H to He >The overall neutrino production rate is well known based on the amount of light emitted by the sun >There are too few electron neutrinos; seen by a number of experiments >From SNO’s NC sample we know the overall solar flux is bang on >Looks like e => active oscillations w/MSW KamLand, a ~100 km baseline reactor experiment, confirms A very consistent picture Solar Neutrinos: Case Closed Phys. Rev. Lett. 89, 011301 (2002) hep-ex/0212021

8. EIC2 3/04 Page 8 Atmospheric Neutrinos M. Ishitsuka NOON04 L ~ 20 km L ~ 10 4 km Earth Consistent results >Super K results are the standard; other experiments are consistent >Electrons show no effect Reactors give the best limits >Matter effects tell us it’s a transition to normal neutrinos Super K

9. EIC2 3/04 Page 9 LSND They observe a 4  excess of e events Spatial distributions as expected Allowed region strongly constrained by other experiments Phys. Rev. D 64, 112007 (2001).

10. EIC2 3/04 Page 10 Parameter Summary The 3 mass signatures are not consistent with 3 neutrinos Either >A signature is incorrect >Or there is another non-interacting type of neutrino (aka sterile) >Or CPT volation >Miniboone testing LSND result at Fermilab right now Adapted from H. Murayama; PDG

11. EIC2 3/04 Page 11 Current Summary of Active Neutrino Parameters (ignoring CPT and/or sterile) Mass splittings Angles

12. EIC2 3/04 Page 12 K2K Experiment Man-Made Neutrinos Neutrinos from KEK to SuperK >P p = 12 GeV >Goal of 10 20 protons on target (POT) >5 kW beam power >Baseline of 250 km >Running since 1999 >50 kT detector They see 44 events >Based on near detector extrapolations, they expected 64 ± 6 events without oscillations Results are consistent with atmospheric data but not yet statistically compelling hep-ex/0212007 (K2K)

13. EIC2 3/04 Page 13 The Next 5 Years The current generation of oscillation experiments are designed to >Confirm atmospheric results with accelerator ’s (K2K) >Resolve sterile neutrino situation (MiniBooNE; more later) >Demonstrate oscillatory behavior of  ’s (MINOS) >Refine the solar region (KamLAND) >Demonstrate explicitly    oscillation mode by detecting  appearance (OPERA) >Precise (~10%) measurement of ATM parameters (MINOS) >Improve limits on   e subdominant oscillation mode, or detect it (MINOS, ICARUS) >Test of matter effects (SNO)

14. EIC2 3/04 Page 14 Long Baseline Example: MINOS Detectors & NuMI Beam Near Detector: 980 tons Far Detector: 5400 tons A 2-detector long-baseline neutrino oscillation experiment in a beam from Fermilab’s Main Injector

15. EIC2 3/04 Page 15 On the Fermilab Site 120 GeV Main Injector’s (MI) main job is stacking antiprotons and as an injector in the Tevatron Most bunches are not used required for p- bar production So… >Put them on a target and make neutrinos Same thing is also done with the 8 GeV booster

16. EIC2 3/04 Page 16 Making a Neutrino Beam Wilson Hall for Scale Target Hall Near Detector Hall Absorber Hall Proton carrier Decay volume Muon Monitors

17. EIC2 3/04 Page 17 NuMI Beam & Spectra  CC Events/kt/year Low Medium High 470 1270 2740  CC Events/MINOS/2 year Low Medium High 5080 13800 29600 4x10 20 protons on target/year 4x10 13 protons/2.0 seconds 0.4 MW beam power (0.25 MW initially)

18. EIC2 3/04 Page 18 Target Target & Horn Graphite target Magnetic horn ( focusing element ) 250 kA, 5 ms pulses

19. EIC2 3/04 Page 19 NuMI Target Hall

20. EIC2 3/04 Page 20 MINOS Charged-Current Spectrum Measurement

21. EIC2 3/04 Page 21 Status in ~5 Years We will know >Both mass differences (Kamland, MINOS) >2 of the 3 angles @ 10% (Kamland+SNO; SK+MINOS) >Sign of one of the mass differences (Solar MSW) >First tests of CPT in allowed regions (MINOS, MiniBooNE) Probably still missing >Last angle? * >Confirmation of matter effects * >Sign of the other mass difference; mass hierarchy * >CP in neutrinos * >Absolute mass scale (double beta; cosmology) >Majorana or Dirac (double beta) * addressable with “super beam” experiments

22. EIC2 3/04 Page 22 Super Beam Rules of Thumb It’s the [proton beam power] x [mass] that matters >Crudely linear dependence of pion production vs E proton >Generally energy & cycle time are related and hence the power is conserved within a synchrotron >Remember that we design an experiment at constant L/E >The beam divergence due to the energy of the pions is balanced by the boost of the pions and the v cross section at constant L/E

23. EIC2 3/04 Page 23 Long Baseline Goals Find evidence for   e >One small parameter in phenomenology Determine the mass hierarchy >Impacts model building Is  23 exactly equal to 1??? – test to 1% level Precision measurement of the CP-violating phase  >Cosmological matter imbalance significance >Potentially orders of magnitude stronger than in the quark sector Resolve  ambiguities >Significant cosmological/particle model building implications

24. EIC2 3/04 Page 24 Super Beam Phasing Part of the DoE Roadmap Phase I (~next 5 years) MINOS, OPERA, K2K Phase II (5-10 years) >50kt detector & somewhat less than 1 MW J2K, NO A, super reactor experiment Phase III (10+ years; super beams) >Larger detectors and MW+ beams JPARC phase II + Hyper K (Mton ĉ ) NuMI + Proton driver + 2 nd 100kt detector CERN SPL + Frejus (0.5 Mton ĉ ) BNL super beam + UNO (0.5 Mton ĉ ) @ NUSL Phase IV (20 years ???) >Neutrino factory based on muon storage ring

25. EIC2 3/04 Page 25 Phase II e.g. Off-Axis Searches for v e Appearance 2 off-axis programs >JPARC to Super K (T2K; Funded) >NuMI to NO A (Under Review) Main goal >Look for electron appearance <1% (30X current limits) >Off-axis detector site to get a narrow-band beam >Fine-grain detectors to reduce NC  o background below the intrinsic beam contamination >Statistics limited for most any foreseeable exposure NuMI On-axis

26. EIC2 3/04 Page 26 Interpretation of Results There are matter effects visible in the 820km range >Provides handle on CP phase, mass hierarchy but… >Ambiguities with just a single measurement In addition >If sin 2 (2  23 ) = 0.95 >sin 2 (  23 ) = 0.39 or 0.61 >Cosmology cares Rough equivalence of reactor & antineutrino measurements >Eventually need 2 nd energy (AKA detector position) in same beam to resolve at narrow-band beam NO A Goal

27. EIC2 3/04 Page 27 Phase III e.g. BNL Super Beam + UNO Turn AGS into a MW beam >10X in AGS beam power >Not same upgrades as eRHIC >Use a very long baseline >Wide-band or off-axis beam >White paper released Mton-class proton decay detector called UNO envisioned at the National Underground Lab (NUSL) >Location not picked but any of the possibilities are compatible with this concept >LOI to funding agencies this year ~2500 km NuSL EIC

28. EIC2 3/04 Page 28 Very Long Baselines Somewhat Improved Reach & … Wide-band beam accesses a large range of the spectrum gives access to resolve all ambiguities

29. EIC2 3/04 Page 29 Near future short baseline program Recent proposals >MINERvA @ main injector >FINeSSE @ Fermilab booster >Fine grained devices >Most topics will still benefit from higher Stats MINERvA

30. EIC2 3/04 Page 30 Short Baseline Neutrinos Neutrino properties >Sterile neutrinos after MiniBooNE (few eV 2 range) R-process in supernovae astro- ph/0309519 hep=ph/0205029 suggests searches beyond LSND indicated region >Magnetic moment Required if massive Dirac neutrinos Suggested by beyond SM models Models go from minimal BSM model of 3x10 -19 µ B to current limits of 6.8x10 -10 µ B (in v µ ) Neutrinos as a probe of nucleon structure >Form factors (low energy) Current generations to probe to  s ~ ± 0.04 >Structure Functions (higher-energy)

31. EIC2 3/04 Page 31 Sterile Beyond LSND/MiniBooNE Current proposals a more coverage for sterile neutrinos through controlling systematics with 2-detector measurements An EIC class injector would allow the statistics to fully exploit this approach >Needs study to determine the possible reach and systematic limits

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33. EIC2 3/04 Page 33 Oscillation experiments run in the sub GeV to few GeV range Extracting neutrino spectra complicated by using an energy range where a lot of things matter >Quasi-elastic, resonance production and DIS contribute significantly >Coherent mechanisms important >The difference between E vis and E v due to nuclear effects, Fermi motion, rescattering … >Also requires a subtraction of NC events that fake low energy CC events Neutrino experiments rely on MC A useful collaboration between neutrino & electron scattering communities promises to be useful for both >NuInt conference series 3 rd meeting this week at Gran Sasso http://nuint04.lngs.infn.it/

34. EIC2 3/04 Page 34 “Medium Energy” Physics A high-intensity neutrino beam offers new possibilities for the study of nucleon and nuclear structure. e.g. NuMI has very similar kinematic coverage to current generation of JLab experiments. A new window on many of the questions currently being explored in JLab experiments.

35. EIC2 3/04 Page 35 Physics Goals Quasi-elastic ( + n -->    + p, 300 K events off 3 tons CH) >Precision measurement of  E ) and d  /dQ important for neutrino oscillation studies. >Precision determination of axial vector form factor (F A ), particularly at high Q 2 >Study of proton intra-nuclear scattering and their A-dependence (C, Fe and Pb targets) Resonance Production (e.g. + N ---> /    600 K total, 450K 1  ) >Precision measurement of  and d  /dQ  for individual channels >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 Coherent Pion Production ( + A --> /    25 K CC / 12.5 K NC  >Precision measurement of  for NC and CC channels >Measurement of A-dependence >Comparison with theoretical models

36. EIC2 3/04 Page 36 Physics Goals Nuclear Effects (C, Fe and Pb targets) >Final-state intra-nuclear interactions. Measure multiplicities and E vis off C, Fe and Pb. >Measure NC/CC as a function of E H off C, Fe and Pb. >Measure shadowing, anti-shadowing and EMC-effect as well as flavor-dependent nuclear effects and extract nuclear parton distributions. MINER A and Oscillation Physics >MINER A measurements enable greater precision in measure of  m, sin 2  23 in MINOS >MINER A measurements important for  13 in MINOS and off-axis experiments >MINER A measurements as foundation for measurement of possible CP and CPT violations in the  sector  T and Structure Functions (2.8 M total /1.2 M DIS events) >Precision measurement of low-energy total and partial cross-sections >Understand resonance-DIS transition region - duality studies with neutrinos >Detailed study of high-x Bj region: extract pdf’s and leading exponentials over 1.2M DIS events Most all of these would benefit from 10x or more statistics beyond proposals

37. EIC2 3/04 Page 37 Physics Goals Strange and Charm Particle Production (> 60 K fully reconstructed exclusive events) - >Exclusive channel  E ) precision measurements - importance for nucleon decay background studies. >Statistics sufficient to reignite theorists attempt for a predictive phenomenology >Exclusive charm production channels at charm threshold to constrain m c Generalized Parton Distributions (few K events) >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. MINER A would expect a few K signature events in 4 years. >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) >provide constraints on axial form factors, including transition nucleon --> N* form factors

38. EIC2 3/04 Page 38 Beta Beam Concept Goal is to make a very well understood neutrino beam (flux, spectrum, and no background) >Zuchelli (2002) Start with radioactive ions >Use ions that beta decay with high Q and reasonable lifetime >Boost them with a  in the range 55 to 140 >Result would be a highly collimated beam

39. EIC2 3/04 Page 39 Beta beams recently proposed for High Energy  13 & CP violation Low EnergyNeutrino – nucleus interactions Lowest EnergyNeutrino Magnetic Moments

40. EIC2 3/04 Page 40 Example Design from CERN Lindroos (2003)

41. EIC2 3/04 Page 41 CP violation &  13 CERN vision for oscillation studies uses 200 km baseline with 0.44 Mton detector For  13 = 3 deg appearance rates (10 yr) > 18 Ne66 events (osc,) > 6 He32 events (osc.) T Violation test >  beam vs conventional v e => v µ v µ => v e

42. EIC2 3/04 Page 42 Neutrino-Nucleus Interactions Lower energy beta beam (boosted to 10s of MeV) Applications for astrophysics >Supernova neutrino detection >Supernova nucleosynthesis >Solar Neutrino Detection Currently >Carbon only know to 4% - 10% >D, 56 Fe, 127 I reported with ~40% error Cross sections ~ 10 -41 cm 2 >Can make a 10% measurement in 10 ton detector with 10 15 v/s over in a reasonable run Volpe (2003)

43. EIC2 3/04 Page 43 Magnetic Moment Neutrinos have mass there therefore the have a magnetic moment Very sensitive to physics beyond the standard model Current limits vary by species but are in the range of 10-15  B (e.g. from reactor studies) Would need 10 15 ions/s for reasonable sensitivity

44. EIC2 3/04 Page 44 Beam Intensity Current experiments near-term experiments (next 5 years) are fraction of a MW beam power >Few x 10 20 to 10 21 protons on target >eLIC booster in routine use on target (1-3)x10 22 per year Up to 4MW >Each generation proposes factor of 10 X in [mass] x [power]

45. EIC2 3/04 Page 45 Current, Planned, & Dream Super Beam Facilities ProgramP p E v P (MW)L (km)yr K2K121.50.00525099 MiniBooNE 80.70.050.502 NuMI (initial)1203.50.2573505 NuMI (full design)1203.50.473508 CNGS60017.00.273505 JPARC to SK 501.00.829508 NO A (NuMI Off-Axis)1201.50.481009 SNS1.30.11.40.02soon? Super Reactorn/a0.011015 yrs? JPARC phase II500.84295 Fermilab Proton driver1201.81.9735/1500 CERN SPL (proton linac) 2 0.34130 AGS Upgrade301-722500 eLIC injector201-542500 Now/next couple years ~5 years10-15 years

46. EIC2 3/04 Page 46 Relationship to EIC Complexes At BNL >Use AGS for a neutrino program while is also feeding RHIC & eRHIC At JLab >Use Large Booster for a neutrino program when not loading the storage ring >Probably cleanest best if electron and proton booster functions are separated 200 MeV Drift Tube Linac BOOSTER High Intensity Source plus RFQ Superconducting Linacs To RHIC 400 MeV 800 MeV 1.2 GeV To Target Station AGS 1.2 GeV  28 GeV 0.4 s cycle time (2.5 Hz) 0.2 s 200 MeV

47. EIC2 3/04 Page 47 What about eLIC? The distance to the NuSL site is about the same for either BNL or JLab Large Injector gets used for few minutes per fill of the collider >Rest of the time could be used for “pinging” a target >Beam power for eLIC proton injector competitive with other super beams >Implies some machine design issues Needs 11 o angle to hit NUSL >Similar ground water issues to BNL Site is potentially restrictive but fortunately the beam line would run nearly parallel to Jefferson Ave (~10 o )

48. EIC2 3/04 Page 48 Reference/Links Long baseline >T2Khttp://neutrino.kek.jp/jhfnu/ & hep-ex/0106019 >NOvA http://www-off-axis.fnal.gov/notes/public/pdf/offaxis0033/offaxis0033.pdf >BNL Super beamhep-ex/0305105 >CERN SPLCERN 2000-012 >Beta beamhttp://beta-beam.web.ch/beta-beam Short baseline >MINERvAhttp://www.pas.rochester.edu/minerva/ >FINeSSEhep-ex/0402007 APS neutrino study; super beam working group workshop two weeks ago >http://www.bnl.gov/physics/superbeam/ >Retreat and working group report this year

49. EIC2 3/04 Page 49 Summary A rich field for investigation of neutrino oscillations using long & very long baselines >Considerable beyond-SM & cosmology value Neutrino scattering to structure Proton injector for EIC has potential to be a world class neutrino source on a competitive time scale Connections between NUSL, neutrino community, and EIC promise a broad program embracing different communities with orthogonal uses of the facility >A potentially powerful combination