Neutrino oscillation physics with a FNAL Proton Driver

1
Neutrino oscillation physicswith a FNAL Proton
Driver

• NuFact 05, Frascati, Italy
• June 23, 2005
• Walter Winter
• Institute for Advanced Study, Princeton
• Editors Steve Brice, Debbie Harris (FNAL),
  Walter Winter (IAS)

2
Contents

• Introduction
• Performance indicators
• Proton Driver (PD) physics scenarios
• Some examples for PD experiments
• PD and evolution of the global program
• Summary

3
What is a Proton Driver?(a theorists
perspective)

• A terribly complicated machine to obtain more
  protons
• Machine part of the FNAL proton driver
• LINAC Main injector modifications (Giorgio
  Apollinaris talk)
• Goal 8 GeV and (up to) 120 GeV protons at 2 MW
• Factor 5-10 past current FNAL proton source at
  120 GeV
• Cost 300-500M

Proton Driver Higher Luminosities
4
Why do we need a Proton Driver?

• Example sin22q13 sensitivity limit at
  NOvAAppearance rate prop. to sin22q13 (1st
  approximation)Sensitivity limit
• E. g. Factor two better limit factor four in
  luminosity
• Thus Much higher luminosities required to go
  further!
• 5 x Flux Proton Driver
• 5 x Running time 25 years (unrealistic)
• 5 x Detector mass 150kt (150M x 5 even more
  exp.)

L Flux x Detector mass x Running time
Recyclable for other exps
Probably not re-usable
5
Fermilab PD study Facts

• Two partsHow to built a more powerful proton
  source (W.Foster)What to do with the protons (S.
  Geer)
• The Fermilab Director has requested a study ,
  which will require documentation sufficient to
  establish mission need as defined by the DOE CD-0
  process.
• Study launched at PD Workshop at Fermilab in Oct.
  2004
• Directors review in March 2005
• Missing working group reports CD0
  documentationwill probably be publically
  available soon

6
Fermilab PD study - Structure
PD study (Physics part)CD0 documentation for
DOES. Geer
Neutrino oscillationsS. Brice, D. Harris, W.
WinterTHIS TALK!Authors (preliminary)Antusch
, Bazarko, Cooper, DeJongh, Diwan, Feldman,
Finley, Geer, Huber, deGouvea, Jansson,Kersten,
Lindner, Mena, Michael,Parke, Ratz, Rolinec,
Schwetz, Stefanski, Van de Water
Neutrino scatteringJ. Morfin, R. Ransome, R.
TayloeFundamental neutrino properties(X-sectio
n measurem.for osc. Experiments,neutrino-electro
n scattering) Fundamental propertiesof matter
Broader physics program T. Bowles, H. Cheung,
D. Christian, G. Greene, P. Kasper, M.
Mandelkern, P. Ratoff, R. Ray,R. Roberts, H.
Nguyen, T. YamanakaMuon physics (EDM, muon
g-2, rare decays) Kaon, Pion, Neutron, and
Antiproton experiments
7
Potential users of the FNAL PD
NOvA
MiniBOONE
Super-NOvA(2nd detector)
Others?
Proton Driver(machine)
New beamline BBsuperbeam FNAL-DUSEL
multi-GeV
Neutrino factory
some GeV
New beamlineuse all protonsBB n x NBB
b-Beam
120 GeV
8 GeV
8
Why is the neutrino oscillation part so
challenging?

• Many potential experiments using the proton
  driver
• Which of these experiments should one build
• Depends on physics case!
• Key questions
• Does one need the FNAL proton driver in any
  physics case?
• What does one do with it then?
• Should be answered by neutrino oscillation study
• PD Study has a quite strategical character

9
Pre-Proton Driver program

• PD Timescale Starts operation 2014?
• Ten more years to go until then
• What happens until then (physics-wise)?
• Pre-Proton Driver 2005 2014US
  program European/Japanese programMiniBOONE KE
  KMINOS CNGSNOvA T2K

(Chapter 3, Neutrino Oscillation Document NOD)
10
Proton Driver Physics cases

• Main scenariosDeal with following questionsq13
  discovered or not? How large is q13?
• How measure the mass hierarchy and CP violation?
• Special cases
• LSND confirmed
• q23 still consistent with maximal mixing
• Something unexpected happens
• (For details, see working group report)

(Chapters 4-6, NOD)
(Chapter 7, NOD)
11
Predictions for future experiments(or How to
simulate PD-based experiments)

• Existing experiments

• Future experiments

? But only one set realized by nature!
Simulation of future experiments Hypothesis
testing
12
Simulated versus fit parameters
Fit parameters
Simulated/true params

• Represent the values implemented by nature
• Known within current limits
• Change the event rates, top.
• Have to be interpreted likeIf the value of is
  , then the performance will be - Luck or
  not luck?
• Used for risk minimization!

• Determine the precision of the quantity of
  interest
• Unused parameteres are usually marginalized
  over (projection onto axis/plane of interest)
• Source of correlations!

13
q13 performance indicators

• q13 exclusion limit (sensitivity limit)
• Describes the new q13 limit for the hyopthesis of
  no signal (q130)
• Correspond to new limit after the experiment has
  been (unsuccessfully) performed
• Define as largest fit value of q130, which fits
  true q130
• Straightfoward inclusion of correlations and
  degeneracies
• Does not depend on the simulated dCP and mass
  hierarchy!
• q13 discovery reach
• Describes if q130 can be excluded for the
  hyopthesis of a certain set of parameters
  (q13gt0)
• Almost no correlationsdegeneracies (since fit
  q130)
• Depends on simulated q13, mass hierarchy, and dCP

14
Discovery plots and Fraction of dCP
Read For sin22q130.04, we expect a discovery
for 20 of all values of dCP
Sensitive region as function of true q13 and dCP
New primer in PD-NOD!
Fraction of dCP for successful discovery
dCP values now stacked for each q13
15
Fraction of dCP Measure for luck?

• Remember Only one set of simulated values
  actuallyrealized by nature!
• For uniform distribution in dCPFraction of dCP
  Probability to discover dCP
• dCP comes from a complex phase factor eid in the
  mixing matrixThus Distribution in sin d
  theoretically unnatural!?

No luck needed works for all d, hier.
Typical d50-50 chance
Best case d, hierarchy
16
Main PD scenarios ... from q13 exclusion limit
at PD startup
Need substantially more thanexisting beamline
detectorBut superbeams way to go
Conceptual casesin PD study
Probably need neutrino factory
Could work on CP violationmass hierarchywith
existing beamline det.
NUENuMI Up-graded Experiment NOvA
Scenario 3Discovery unlikely until PD startup
Scenario 1Certainly discovereduntil PD startup
Scenario 2Discovery likely before PD startup
17
Scenario 1 sin22q13 larger than 0.04
CP fraction 1 not possible!
NUE NOvA T2K T2KJapenese PD T2HK
T2KJapanese PDHyper-K-Detector

• Excellent results with FNAL-PD possibly
  existing equipment (NOvA)
• Synergy with Japanese program (especially for
  mass hierarchy)
• If Japanese program not funded Other options
  (next slides)

18
Scenario 2 0.01 lt sin22q13 lt 0.04
NUE NOvA 2nd NUE Super-NOvA

• Second NUMI off-axis detector promising
  alternative
• New long baseline experiment could do it all
• What specific option preferred needs further
  study

19
Example 1 BB FNAL-Homestake

• Two-Peak Structure still visible at 1290km
• FNAL-Homestake very competitive for q13 and also
  dCP
• See hep-ex/0407047 for more details

2540km
1290km
Figures from M.Diwan
20
Example 2 2 MW 2 MW beam
8m
30 mR maximum off axis
D.Michael, C.White, M.Messier

• 1290km
• Uses all the
• protons from
• Booster
• Main Injector

150kT Liquid Argon
200M
4m
Consider LAr and H2OC
90 CL 99 CL
8 GeV protons
120 GeV protons
21
Scenario 3 sin22q13 smaller than 0.01
NuFact50kt magn. Iron det.44 year running4
MW target power(1021 useful muon
decays/year)50 GeV neutrinos

• For large sin22q13gt0.003 New long baseline
  experiment interesting alternative
• For smaller values Neutrino factory (or b-Beam)
  can do measurements in large fraction of
  parameter space (see P. Hubers talk)

22
Example b-Beam at Fermilab?
Stretched Tevatron aimed at Soudan Total
circumference approximately 2 x
Tevatron 320m elevation _at_ 58 mrad
A. Jansson
(Huber, Lindner, Rolinec, WW, to appear)
23
Evolution of q13 discovery limit

• Characterize dependence on dCP as bands
  reflecting all possible chases
• Choose starting times luminosities as close as
  possible to values in respective LOIs/proposals
• All exps five years running
• New generation will quickly determine potential
• Reactor experiments provide complementary
  information!
• For inverted hierarchy Beam limits shift
  somewhat down!

(from FNAL proton driver study, to appear)
24
Examples for q13 cases (1)

• Assume Actual value of sin22q13 0.03

2012-2013 q13 signal likely at superbeams or
reactor experiments
PDNUE2nd NUE very competitiveFastcost
efficient alternative to T2HK!?
25
Examples for q13 cases (2)

• Assume Actual value of sin22q13 0.007

Discovery of q13 unlikely without PD and
impossible for T2K
If no PD at Fermilab, probably no further
superbeam program!
But One could have done almost of all the
physics with a superbeam program!
26
Summary

• We need the FNAL proton driver in all physics
  cases (but not all possible discussed
  experiments!)
• The FNAL Proton Driver is the next logical step
  in the FNAL neutrino oscillation program beyond
  NOvA
• The FNAL-based neutrino oscillation program is
  unique, because
• There are already existing experiments. Thus No
  complete program from scratch
• NUMI beamline is so far the only beamline with
  large enough matter effects to potentially
  resolve the mass hierarchy
• Synergy with reactor program Japanese program
• For more see http//protondriver.fnal.gov/