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

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

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 Page 2

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) Page 3

4 Oscillation Formalism With 2 neutrino basis (weak force & mass) there can be flavor oscillations ν l = U li ν i The probability that a neutrino (e.g. ν µ ) will look like another variety (e.g. ν τ ) will be P(ν µ ν τ ; t)= <ν τ ν µ (t)> 2 A 2-component unitary admixture characterized by θ results in P(ν µ ν τ ) = sin 2 2θ sin 2 (1.27 m 2 L/E) Experimental parameter L (km) /E (GeV) Oscillation (physics) parameters sin 2 2θ (mixing angle) P(v µ >ν µ ) E (GeV) m 2 = m τ2 -m µ2 (mass squared difference, ev 2 ) 1.0 m 2 = ev 2 ; L = 735 km Page 4

5 3-Flavor Oscillation Formalism In 3 generations, the mixing is given by ν > Where, s jk sinθ jk and c jk cosθ jk > There are 3 m 2 s (only 2 are independent) m c 13 c 12 c 13 s 12 s 13 e iδ U = c 23 s 12 s 13 s 23 c 12 e iδ c 23 c 12 s 13 s 23 s 12 e iδ c 13 s 23 s 23 s 12 s 13 c 23 c 12 e iδ s 23 c 12 s 13 c 23 s 12 e iδ c 13 c = m1 m2 m23 = m2 m3, > 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), m = m m > Electron neutrinos see a different potential due to electrons in matter l = U li ν i Page 5

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 Page 6

7 Solar Neutrinos: Case Closed 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 Phys. Rev. Lett. 89, (2002) > 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 hep-ex/ > Looks like ν e => ν active oscillations w/msw KamLand, a ~100 km baseline reactor experiment, confirms A very consistent picture Page 7

8 Atmospheric Neutrinos 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 M. Ishitsuka NOON04 ν L ~ 20 km ν Earth ν ν ν ν L ~ 10 4 km Page 8

9 LSND They observe a 4σ excess of ν e events Spatial distributions as expected Allowed region strongly constrained by other experiments Phys. Rev. D 64, (2001). Page 9

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 Page 10

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

12 K2K Experiment Man-Made Neutrinos Neutrinos from KEK to SuperK > P p = 12 GeV > Goal of 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/ (K2K) Page 12

13 The Next 5 Years The current generation of oscillation experiments are designed to > Confirm atmospheric results with accelerator ν s (K2K) > Resolve sterile neutrino situation (MiniBooNE; more later) > Demonstrate oscillatory behavior of ν µ s (MINOS) > Refine the solar region (KamLAND) > Demonstrate explicitly ν µ ν τ oscillation mode by detecting ν τ appearance (OPERA) > Precise (~10%) measurement of ATM parameters (MINOS) > Improve limits on ν µ ν e subdominant oscillation mode, or detect it (MINOS, ICARUS) Page 13

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

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 Page 15

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

17 NuMI Beam & Spectra ν µ CC Events/kt/year Low Medium High ν µ CC Events/MINOS/2 year Low Medium High x10 20 protons on target/year 4x10 13 protons/2.0 seconds 0.4 MW beam power (0.25 MW initially) Page 17

18 Target & Horn Graphite target Magnetic horn (focusing element) 250 ka, 5 ms pulses Target Page 18

19 NuMI Target Hall Page 19

20 MINOS Charged-Current Spectrum Measurement Page 20

21 Status in ~5 Years We will know > Both mass differences (Kamland, MINOS) > 2 of the 3 10% (Kamland+SNO; SK+MINOS) > Sign of one of the mass differences (Solar MSW) 2 > 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) Atmospheric Solar Solar Atmospheric * addressable with super beam experiments Page 21

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 Page 22

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

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, NOνA, 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 NUSL Phase IV (20 years???) > Neutrino factory based on muon storage ring Page 24

25 Phase II e.g. Off-Axis Searches for v e Appearance 2 off-axis programs > JPARC to Super K (T2K; Funded) > NuMI to NOνA (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 π o background below the intrinsic beam contamination > Statistics limited for most any foreseeable exposure NuMI On-axis Page 25

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 (2θ 23 ) = 0.95 > sin 2 (θ 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 NOνA Goal Page 26

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 NuSL ~2500 km EIC Page 27

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

29 Near future short baseline program Recent proposals MINERvA > main injector > Fermilab booster > Fine grained devices > Most topics will still benefit from higher Stats Page 29

30 Short Baseline Neutrinos Neutrino properties > Sterile neutrinos after MiniBooNE (few ev 2 range) R-process in supernovae astroph/ hep=ph/ 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) Page 30

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 Page 31

32 Page 32

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 Page 33

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. Q 2 (GeV 2 ) H1 ZEUS JLAB NuMI Fixed Target Experiments: CCFR, NMC, BCDMS, E665, SLAC x Page 34

35 Physics Goals Quasi-elastic (ν + n --> µ + p, 300 K events off 3 tons CH) > Precision measurement of σ(e ν ) and dσ/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. ν + N ---> ν /µ +, 600 K total, 450K 1π) > Precision measurement of σ and dσ/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 π< >2 π < > 3 π final states Coherent Pion Production (ν + A --> ν /µ + Α + π, 25 K CC / 12.5 K NC) > Precision measurement of σ(ε) for NC and CC channels > Measurement of A-dependence > Comparison with theoretical models Page 35

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. MINERνA and Oscillation Physics > MINERνA measurements enable greater precision in measure of m, sin 2 θ 23 in MINOS > MINERνA measurements important for θ 13 in MINOS and off-axis experiments > MINERνA measurements as foundation for measurement of possible CP and CPT violations in the ν sector σ 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 Page 36

37 Physics Goals Strange and Charm Particle Production (> 60 K fully reconstructed exclusive events) - > Exclusive channel σ(e ν ) 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. MINERνA 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 Page 37

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 γ in the range 55 to 140 > Result would be a highly collimated beam 6 He 6 Li + e + ν e 18 Ne 18 F + e + + ν e Page 38

39 Beta beams recently proposed for High Energy θ 13 & CP violation Low Energy Neutrino nucleus interactions Lowest Energy Neutrino Magnetic Moments Page 39

40 Example Design from CERN Lindroos (2003) Page 40

41 CP violation & θ 13 CERN vision for oscillation studies uses 200 km baseline with 0.44 Mton detector For θ 13 = 3 deg appearance rates (10 yr) > 18 Ne 66 events (osc,) > 6 He 32 events (osc.) T Violation test > β beam vs conventional v e => v µ v µ => v e Page 41

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 ~ cm 2 > Can make a 10% measurement in 10 ton detector with v/s over in a reasonable run Volpe (2003) Page 42

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 10-15µ B (e.g. from reactor studies) Would need ions/s for reasonable sensitivity Page 43

44 Beam Intensity Current experiments near-term experiments (next 5 years) are fraction of a MW beam power >Few x to 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] Page 44

45 Current, Planned, & Dream Super Beam Facilities Program P p E v P (MW) L (km) yr K2K MiniBooNE NuMI (initial) NuMI (full design) CNGS JPARC to SK NOνA (NuMI Off-Axis) SNS soon? Super Reactor n/a yrs? JPARC phase II Fermilab Proton driver /1500 CERN SPL (proton linac) AGS Upgrade elic injector Now/next couple years ~5 years years Page 45

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 High Intensity Source plus RFQ 200 MeV Drift Tube Linac BOOSTER 200 MeV 400 MeV Superconducting Linacs 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 0.2 s To RHIC Page 46

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 ) Page 47

48 Reference/Links Long baseline > T2K & hep-ex/ > NOvA > BNL Super beam hep-ex/ > CERN SPL CERN > Beta beam Short baseline > MINERvA > FINeSSE hep-ex/ APS neutrino study; super beam working group workshop two weeks ago > > Retreat and working group report this year Page 48

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 Page 49