Neutrino Studies at an EIC Proton Injector

Jeff NelsonCollege of William & Mary

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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

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Cliffs Notes on Neutrinos

• There are only 3 “light” active neutrino flavors (from Z width) > Electron, muon, & tau types

> Cosmological mass limits imply ∑mν < 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)

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• 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)= |<|(t)>|2

• A 2-component unitary admixture characterized by results in

P( ) = sin22 sin2(1.27 m2 L/E)

• Experimental parameter

L (km) /E (GeV)

• Oscillation (physics) parameters

sin22(mixing angle)

m2 = m2 - m

2 (mass squared difference, eV2)

E (GeV)

0.0

1.0

0 1 2 3 4 5 6 7 8 9 10P(v

)

Oscillation Formalism

ilil U

m2 = 0.003 eV2; L = 735 km

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3-Flavor Oscillation Formalism

• In 3 generations, the mixing is given by

> Where, and

> There are 3 m2’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

21

23

231

23

22

223

22

21

212 ,, mmmmmmmmm

U c13c12 c13s12 s13e

i

c23s12 s13s23c12ei c23c12 s13s23s12e

i c13s23

s23s12 s13c23c12ei s23c12 s13c23s12e

i c13c23

c jk cos jk

s jk sin jk

ilil U

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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…

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•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

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Atmospheric Neutrinos

M. Ishitsuka NOON04

L ~ 20 km

L ~ 104 km

Eart

h

• 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

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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).

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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

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Current Summary of Active Neutrino Parameters (ignoring CPT and/or

sterile)

• Mass splittings

• Angles

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K2K ExperimentMan-Made Neutrinos

• Neutrinos from KEK to SuperK

> Pp = 12 GeV

> Goal of 1020 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)

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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)

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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

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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

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Making a Neutrino Beam

Wilson Hall for Scale

Target HallNear Detector Hall

Absorber Hall

Proton carrierDecay volume

Muon Monitors

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NuMI Beam & Spectra

CC Events/kt/year Low Medium High 470 1270 2740

CC Events/MINOS/2 year Low Medium High 5080 13800 29600

4x1020 protons on target/year4x1013 protons/2.0 seconds

0.4 MW beam power

(0.25 MW initially)

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Target

Target & Horn

• Graphite target • Magnetic horn (focusing element)

• 250 kA, 5 ms pulses

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NuMI Target Hall

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MINOS Charged-Current Spectrum Measurement

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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

3

2

1

Atm

ospheric S

olar

3

2

1

Atm

ospheric S

olar

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Super Beam Rules of Thumb

• It’s the [proton beam power] x [mass] that matters

> Crudely linear dependence of pion production vs Eproton

> 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

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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

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Super Beam PhasingPart 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, NOA, super reactor experiment

• Phase III (10+ years; super beams)> Larger detectors and MW+ beams

• JPARC phase II + Hyper K (Mton ĉ)• NuMI + Proton driver + 2nd 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

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Phase II e.g. Off-Axis Searches for ve Appearance

• 2 off-axis programs> JPARC to Super K (T2K; Funded)> NuMI to NOA (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

NuMIOn-axis

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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 sin2(223) = 0.95> sin2(23) = 0.39 or 0.61> Cosmology cares

• Rough equivalence of reactor & antineutrino measurements> Eventually need 2nd energy

(AKA detector position) in same beam to resolve at narrow-band beam

NOA Goal

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Phase IIIe.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

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Very Long Baselines Somewhat Improved Reach & …

Wide-band beam accesses a large range of the spectrum gives access to resolve all

ambiguities

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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

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Short Baseline Neutrinos

• Neutrino properties > Sterile neutrinos after MiniBooNE (few eV2

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 µB to current limits of 6.8x10-10µB (in vµ)

• Neutrinos as a probe of nucleon structure> Form factors (low energy)

• Current generations to probe to s ~ ± 0.04

> Structure Functions (higher-energy)

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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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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 Evis and Ev 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

• 3rd meeting this week at Gran Sasso• http://nuint04.lngs.infn.it/

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“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.

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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 (FA), particularly at high Q2 > 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/dQfor 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

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Physics Goals

• Nuclear Effects (C, Fe and Pb targets)

> Final-state intra-nuclear interactions. Measure multiplicities and Evis off C, Fe and Pb.

> Measure NC/CC as a function of EH off C, Fe and Pb.

> Measure shadowing, anti-shadowing and EMC-effect as well as flavor-dependent nuclear effects and extract nuclear parton distributions.

• MINERA and Oscillation Physics > MINERA measurements enable greater precision in measure of m, sin223 in MINOS> MINERA measurements important for 13 in MINOS and off-axis experiments> MINERA 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-xBj 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

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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 mc

• 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. MINERA 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

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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

eeLiHe 66eeFNe 1818

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Beta beams recently proposed for

• High Energy 13 & CP violation

• Low Energy Neutrino – nucleus interactions• Lowest Energy Neutrino Magnetic Moments

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Example Design from CERN

• Lindroos (2003)

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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)> 18Ne 66 events (osc,)

> 6He 32 events (osc.)

• T Violation test beam vs

conventional

ve=> vµ vµ => ve

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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, 56Fe, 127I reported with ~40% error

• Cross sections ~ 10-41cm2

> Can make a 10% measurement in 10 ton detector with 1015 v/s over in a reasonable run

Volpe (2003)

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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 10-15B (e.g. from reactor studies)

• Would need 1015 ions/s for reasonable sensitivity

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Beam Intensity

• Current experiments near-term experiments (next 5 years) are fraction of a MW beam power>Few x 1020 to 1021 protons on target>eLIC booster in routine use on target

• (1-3)x1022 per year• Up to 4MW

>Each generation proposes factor of 10 X in [mass] x [power]

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Current, Planned, & Dream Super Beam Facilities

Program Pp Ev P (MW) L (km) yr

K2K 12 1.5 0.005 250 99MiniBooNE 8 0.7 0.05 0.5 02NuMI (initial) 120 3.5 0.25 735 05NuMI (full design) 120 3.5 0.4 735 08CNGS 600 17.0 0.2 735 05

JPARC to SK 50 1.0 0.8 295 08NOA (NuMI Off-Axis) 120 1.5 0.4 810 09SNS 1.3 0.1 1.4 0.02 soon?Super Reactor n/a 0.01 10 1 5 yrs?

JPARC phase II 50 0.8 4 295Fermilab Proton driver 120 1.8 1.9 735/1500CERN SPL (proton linac) 2 0.3 4 130AGS Upgrade 30 1-7 2 2500eLIC injector 20 1-5 4 2500

Now/next couple years ~5 years 10-15 years

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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 Sourceplus RFQ

Superconducting Linacs

To RHIC

400 MeV

800 MeV

1.2 GeV

To Target Station

AGS1.2 GeV 28 GeV

0.4 s cycle time (2.5 Hz)

0.2 s 0.2 s

200 MeV

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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 11o 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 (~10o)

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Reference/Links

• Long baseline> T2K http://neutrino.kek.jp/jhfnu/ & hep-ex/0106019 > NOvA http://www-off-axis.fnal.gov/notes/public/pdf/offaxis0033/offaxis0033.pdf > BNL Super beam hep-ex/0305105 > CERN SPL CERN 2000-012> Beta beam http://beta-beam.web.ch/beta-beam

• Short baseline> MINERvA http://www.pas.rochester.edu/minerva/> FINeSSE hep-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

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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