# Presentation: 864513

## Super Beam Experiments

- Douglas Michael
- California Institute of Technology
- NuFACT 03
-  June 5, 2003

-  What’s a Super Beam?
-  The Physics
-  Some of the common features
-  Specific Proposals
-  Jaeri to Super-Kamiokande
-  CERN to Frejus
-  CERN to Gulf of Taranto
-  Fermilab to “Up North” via NuMI
-  Brookhaven to NUSEL (or others?)
-  Conclusions

## Thanks to the following people from whom I have borrowed/collected various slides and figures which I have included in this talk:
J. Cooper, M. Diwan, F. Dydak, A. Kondo-Ichikawa, K. McDonald, M. Mezzetto, T. Nakaya, K. Nishikawa, A. Para, S. Wojcicki
Those are my sources... I appologize if they have borrowed from you and I haven’t followed the chain of acknowledgement.

- J. Cooper, M. Diwan, F. Dydak, A. Kondo-Ichikawa, K. McDonald, M. Mezzetto, T. Nakaya, K. Nishikawa, A. Para, S. Wojcicki
- Those are my sources... I appologize if they have borrowed from you and I haven’t followed the chain of acknowledgement.

- Thanks

## I know it when I see it. (Justice Potter Stewart)
Any conventional neutrino beam experiment where currently there is:
No Accelerator or
No Detector or
No Beamline or
Combinations of all of the above.
A conventional neutrino beam experiment with a whole lot of proton power and a really big detector.
I’ll settle for defining a “Super Beam” experiment as any conventional, long baseline, high energy neutrino beam experiment seriously “proposed” but not yet approved.

- Any conventional neutrino beam experiment where currently there is:
- No Accelerator or
- No Detector or
- No Beamline or
- Combinations of all of the above.
- A conventional neutrino beam experiment with a whole lot of proton power and a really big detector.
- I’ll settle for defining a “Super Beam” experiment as any conventional, long baseline, high energy neutrino beam experiment seriously “proposed” but not yet approved.

- What’s a “Super Beam” Experiment?

## Improved measurement of  disappearance oscillation parameters. 
Any odd energy/distance features?
How close is sin2223 to 1.0? New symmetry?
Measure the m23 mass heirarchy using matter effects. 
Measure 13 or show that it is so small that it is somehow “odd” compared to the other mixing parameters... Mechanism for making it so small?
Attempt to measure CP violation, if 13 is big enough.
Constrain CPT violation (or discover it!)
And what if LSND is confirmed???????? Things get very interesting, and complicated.

- Any odd energy/distance features?
- How close is sin2223 to 1.0? New symmetry?
- Measure the m23 mass heirarchy using matter effects.
- Measure 13 or show that it is so small that it is somehow “odd” compared to the other mixing parameters... Mechanism for making it so small?
- Attempt to measure CP violation, if 13 is big enough.
- Constrain CPT violation (or discover it!)
- And what if LSND is confirmed???????? Things get very interesting, and complicated.

- Physics Goals

##   e oscillation experiment

- 3 unknowns, 2 parameters under control L, E,  neutrino/antineutrino Need several independent measurements to learn about underlying physics
- Note, if there are any sterile ’s things can be more complicated!

## Anatomy of Bi-probability ellipses

**sin****2****2********13**

- 

- ~sin

- ~cos

- Observables are:
- P
- P
- Interpretation in terms of sin22q13, d and sign of Dm223 depends on the value of these parameters and on the conditions of the experiment: L and E

- Minakata and Nunokawa, hep-ph/0108085

- Example from NuMI Off-Axis

## Oscillation probability vs physics parameters

- Parameter correlation: even very precise determination of P leads to a large allowed range of sin2223   _**antineutrino beam**_ is more  important than improved statistics

- Example from NuMI Off-Axis

## ‘On axis’: E=0.43E

- ‘On axis’: E=0.43E

- At this angle, 15 mrad, energy of produced neutrinos is 1.5-2 GeV for all pion energies  very intense, narrow band beam

- The Off-Axis Trick

## ~1GeV  beam

**~1GeV ******** beam**

**Kamioka**

**J-PARC**
**(Tokai)**

**0.75MW  50 GeV PS**

**( conventional ******** beam) **

**Super-K: 22.5 kt**

**JHF 0.75MW + Super-Kamiokande  **

*Plan to start in 2007*

- (hep-ex/0106019)

**4MW  50 GeV PS**

**Hyper-K: 1000 kt**

**Future   Super-JHF 4MW + Hyper-K(~1Mt) ** ~ **JHF+SK**** **_****__** 200**_

**2008?**

- Jaeri-Kamioka Neutrino Experiment

- Kondo-Ichikawa

## J-Parc Facility

**Construction**
**2001****~****2006 (approved)**

- (0.75MW)

**Near detectors (280m,2km)**

-   beam-line
-   budget request submitted

|  | JHF | NuMI
(FNAL) | K2K |
| --- | --- | --- | --- |
| E(GeV) | 50 | 120 | 12 |
| Int.(1012ppp) | 330 | 40 | 6 |
| Rate(Hz) | 0.275 | 0.53 | 0.45 |
| Power(MW) | 0.75 | 0.41 | 0.0052 |

**To SK**

- Kondo-Ichikawa

## Off Axis Beam

**OA3°**

**OA2°**

**OA1°**

**Off Axis Beam**

- (ref.: BNL-E889 Proposal)

**Quasi Monochromatic Beam**
**x2~3 intense than NBB**

**Statistics at SK**
**     ****(OAB2deg,1yr,22.5kt)**
**~4500**** ************ ****tot **
**~3000**** ************ ****CC **
******e****  ****~0.2% at**** ************ ****peak**

**~10****2**** x (K2K)**

**Tuned at oscillation maximum**
**   ****~0.7 GeV**

- Kondo-Ichikawa

## Decay Volume

- Side View

- Top view

- 4MW beam can be accepted.

- Kondo-Ichikawa

## Muon monitors @ ~140m

**Muon monitors @ ~140m**
- Fast (spill-by-spill) monitoring of beam direction/intensity
**First Near detector**  **@280m**
- Neutrino intensity/spectrum/direction
**Second Near Detector @ ~2km**
- Almost same *E*** spectrum as for SK
- Water Cherenkov can work
**Far detector @ 295km**
**Super-Kamiokande (50kt)**

- dominant syst. in K2K

**p**

****

****

**140m**

**0m**

**280m**

**2 km**

**295 km**

- Detectors

- Kondo-Ichikawa

## Measurement of sin2 2θ23 , m223

- (sin22)~0.01     (m2)   ~<1×10-4

**Measurement of sin****2**** 2θ****23 , ********m****2****23**

-  disappearance

**True *********m******23*****2**** (eV****2****)**

******m****2**

- FC, 1-ring, -like events
- Sys. error 10% for near/far
-                    4% energy scale
-                  20% non-QE B.G.

**OAB-3****o**

- (m232 )

**OAB-2****o**

- (sin22)

- MeV

**Based on 5 years running with full 0.75 MW Jaeri Beam**

- Kondo-Ichikawa

## e appearance in JHF-Kamioka 

******e**** appearance in JHF-Kamioka**

**Back ground  for ********e**** appearance search**
-   Intrinsic e component in initial beam
-   Merged 0 ring from  interactions

- Requirement           10% uncertainty for BG estimation

**The 1kt ********0**** data will be studied for exercise**

- Kondo-Ichikawa

## sin2213 from e appearance 

**sin****2****2********13**** from ********e**** appearance**

| sin2213 | Background in Super-K (as of Oct 25, 2001) |  |  |  |  | Signal | Signal + BG |
| --- | --- | --- | --- | --- | --- | --- | --- |
|  |  | e |  | e | total |  |  |
| 0.1 | 12.0 | 10.7 | 1.7 | 0.5 | 24.9 | 114.6 | 139.5 |
| 0.01 | 12.0 | 10.7 | 1.7 | 0.5 | 24.9 | 11.5 | 36.4 |

**sin****2****2********13**

******m****2**

**Off axis 2 deg, 5 years**

**Off axis 2 deg, 5 years**

**at**

**Sin****2****2********13****>0.006 **

**CHOOZ excluded**

- Kondo-Ichikawa

## 3. JHF  experiment -CPV

- 295km
- <E>~0.7GeV

**Tokaimura**

**Kamioka**

**4MW 50GeV Protons**

**0.54Mton Kamiokande**

- n

- Nakaya

##  beam flux

********

********

**~15% diff.**

**(flip horn polarity)**

- Nakaya

##  Hyper-Kamiokande 

**~540kton fiducial volume**

- Nakaya

## Expected signal and Background

|  | signal |  | background |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
|  | =0 | =/2 | total |  |  | e | e |
| e | 536 | 229 | 913 | 370 | 66 | 450 | 26 |
| e | 536 | 790 | 1782 | 399 | 657 | 297 | 430 |

- m212=6.9x10-5eV2
- m322=2.8x10-3eV2
- 12=0.594
- 23=/4
- 13=0.05 (sin2213=0.01)

- :2yr, :6.8yr
- 4MW
- 0.54Mt

- Nakaya

## number of e,e appearance events

- _number of ____e__,____e__ appearance events_

- sin2213=0.01

**# of e****-**** events include BG**

**# of e****+**** events include BG**

**3******** CP sensitivity : |********|>20****o**** for sin****2****2********13****=0.01**

- Nakaya

## CP sensitivity (3) 

- _CP sensitivity (3____)__ _

**no BG**
**signal stat only**

**(signal+BG) stat only**

**stat+2%syst.**

- stat+5%syst.

- stat+10%syst.

- CHOOZ excluded
- sin2213<0.12@m312~3x10-3eV2

**JHF 3******** discovery**

**3******** CP sensitivity : |********|>20****o**** for sin****2****2********13****>0.01 with 2% syst.**

- Nakaya

## 1023 x 2.2 GeV protons per year

- 1023 x 2.2 GeV protons per year
- 4MW

- CERN SPL to Frejus

- “UNO”
- ~500 kT
- water

- “Super-K”
-  ~50 kT
- or

- Mezzetto

## Fluxes for SPL Beam

- Mezzetto

## 13 

- 13

- 13

- 

- 

- Mezzetto

## Off-Axis CNGS to Gulf of Taranto

**1200 km from CERN**

**1150 km**

**1250 km**

**E************GeV)**

**Flux (m****-2****)**

- Dydak

**CNGS neutrino fluxes (per proton)**

********

******e**

- Without oscillations

## Gulf of Taranto Detector

- Dydak

********

********

********

****

****

****

****

****

**+**

****

**~**

**~**

- 2MT fiducial mass running for 3
- years with 5x1019 protons/year

## e

- Oscillation Amplitudes for 800 MeV Neutrinos

**Distance (km)**

******m****2****= 0.0025 eV****2**

******m****2****= 0.001 eV****2**

**Vacuum Oscillation**

**Earth Crust Oscillation**

**************e**

- Dydak

## Off-Axis Numi Beams

- ~ 2 GeV energy :
-  Below t threshold
-  Relatively high rates per proton, especially for _antineutrinos_
- Matter effects to differentiate mass hierarchies
- Baselines 700 – 1000 km

- Para

## Sources of the e background

- At low energies the dominant background is from +e++e+ decay, hence
- K production spectrum is not a major source of systematics
******e** background directly related to the ********** **spectrum at the near detector

- All

- K decays

- e/ ~0.5%

- Para

##    NuMI Off-axis Detector 

- Low Z imaging calorimeter:
- Glass  RPC or
- Drift tubes or
- Liquid or solid scintillator
- Electron ID efficiency ~ 40% while keeping NC background below intrinsic e level
- Well known and understood detector technologies
- Primarily the engineering challenge of (cheaply) constructing a very massive detector
- How massive??
- 50 kton detector, 5 years run =>
- 10% measurement if sin2213 at the CHOOZ limit, or
- 3 evidence if sin2213 factor 10 below the CHOOZ limit (normal hierarchy, =0), or
- Factor 20 improvement of the limit

- Para

## A Modular Detector

- Built in Shipping Containers?

- Cooper

## Cooper

## Signal and background

- Fuzzy track = electron

- Clean track = muon (pion)

- Wojcicki

##     Background examples 

-      NC - 0 - 2 tracks

-  CC - with 0 - muon

- Wojcicki

## Two phase program?

- Phase I? (~ $100-200 M, running 2008 – 2014)
- 50 kton (fiducial) detector with ~35-40%
- 4x1020 protons per year (Nominal NuMI design plan... conservative? 6-8?)
- 1.5 years neutrino (6000  CC, 70-80% ‘oscillated’)
- 5 years antineutrino (6500  CC, 70-80% ‘oscillated’)
- Phase II? ( running 2014-2020)
- 200 kton (fiducial) detector with ~35-40%
- 20x1020 protons per year (needs new proton source)
- 1.5 years neutrino (120000  CC, 70-80% ‘oscillated’)
- 5 years antineutrino (130000  CC, 70-80% ‘oscillated’)

## NuMI Off-Axis Sensitivity for Phases I and II

- We take the Phase II to have 25 times higher POT x Detector mass
- Neutrino energy and detector distance remain
- the same

- Para

## Para

|  | NuMI Off-axis
50 kton, 85% eff,      5 years, 4x1020 pot/y  |  | JHF to SK
Phase I, 5 years |  |
| --- | --- | --- | --- | --- |
|  | all | After cuts | all | After cuts |
| CC (no osc) | 28348 | 6.8 | 10714 | 1.8 |
| NC | 8650 | 19.4 | 4080 | 9.3 |
| Beam e | 604 | 31.2 | 292 | 11 |
| Signal (m223=2.8/3 x 10-3, NuMI/JHF) | 867.3 | 307.9 | 302 | 123 |
| FOM  (signal/bckg) |  | 40.7 |  | 26.2 |

## Determination of mass hierarchy: complementarity of JHF and NuMI

- Combination of different baselines: NuMI + JHF extends the range of hierarchy discrimination to much lower mixing angles

- Minakata,Nunokawa, Parke

- Para

## BNL Homestake  Super Neutrino Beam

**BNL ********Homestake  Super Neutrino Beam**

**2540 km**

**Homestake**

- BNL

- 28 GeV protons, 1 MW beam power
- 500 kT Water Cherenkov  detector
- 5e7 sec of running, Conventional Horn based beam

- Diwan

## AGS Target Power Upgrade to 1 MW

**AGS Target Power Upgrade to 1 MW**

-  the *AGS Upgrade* to provide a source for the 1.0 MW Super Neutrino Beam
-    will cost $265M FY03 (TEC) dollars

- Diwan

## 3-D Neutrino Super Beam Perspective

**3-D Neutrino Super Beam Perspective**

- Diwan

## UNO: The Study Baseline

- 500 kt Water Cerenkov

- 100 kT LANNDD ~Equivalent?

## Neutrino spectrum from AGS

- Proton energy 28 GeV
- 1 MW total power
- ~10** ****14** proton per pulse
- Cycle 2.5 Hz
- Pulse width 2.5 mu-s
- Horn focused beam with graphite target
- 5x10**-5  **/m2/POT @ 1km

- Diwan

## Advantages of a Very Long Baseline

**Advantages of a Very Long Baseline**

-  neutrino oscillations result from
-    the factor sin**2**(****m**32****2** L / 4E)
-    modulating the **** flux for each
-    flavor (here ******** disappearance)
-  the oscillation period is directly
-    proportional to distance and
-    inversely proportional to energy
-  with a *very long baseline *actual
-    oscillations are seen in the
-    data as a function of energy
-  the multiple-node structure of the
-    very long baseline allows the
-    ****m**32****2** to be precisely measured
-    by a *wavelength* rather than an
-    amplitude (reducing systematic
-    errors)

- Diwan

## VLB Application to Measurement of m322

**VLB Application to Measurement of ********m****32****2**

-  the multiple node method of the
-    VLB measurement is illustrated
-    by comparing the BNL 5-year
-    measurement precision with
-    the present Kamiokande results
-    and the projected MINOS 3-year
-    measurement precision; all
-    projected data include both
-    statistical and systematic errors
-  there is no other plan, worldwide,
-    to employ the VLB method (a
-    combination of target power and
-    geographical circumstances
-    limit other potential competitors)
-  other planned experiments
-    can’t achieve the VLB precision

- Diwan

## e Appearance Measurements

******e**** Appearance Measurements**

-  a direct measurement of the
-    appearance of **************e** is important;
-    the VLB method competes well with
-    any proposed super beam concept
-  for values > 0.01, a measurement
-    of sin**2**2******13** can be made (the
-    current experimental limit is 0.12)
-  for most of the possible range of
-    sin**2**2******13**, a good measurement of
-    ******13** and the CP-violation parameter
-    ******CP** can be made by the VLB
-    experimental method

- Diwan

## e Appearance Measurements (Cont.)

******e**** Appearance Measurements (Cont.)**

-  even if sin**2**2******13** = 0, the current
-    best-fit value of ****m**21****2 **= 7.3x10**-5**
-    induces a ******e** appearance signal
-  the size of the ******e** appearance signal
-    above background depends on the
-    value of ****m**21****2**; the figure left
-    indicates the range of possible
-    measured values for the ******e**
-    yields above background for various
-    assumptions of the final value of
-    ****m**21****2**

- Diwan

## Mass -ordering and CP-violation Parameter CP

**Mass -ordering and CP-violation Parameter ********CP**

-  the CP-violation parameter ******CP** can
-    be measured in the VLB exp. And
-    is relatively insensitive to the value
-    of sin**2**2******13**
-  the mass-ordering of the neutrinos
-    is determined in the VLB exp;
-    ******1** < ******2** < ******3** is the natural order
-    but ******1** < ******3** < ******2** is still possible
-    experimentally; VLB determines
-    this, using the effects of matter on
-    the higher-energy neutrinos

- Diwan

## Possible limits  on sin2213  versus CP 

- Possible limits  on sin**2**2******13 ** versus ******CP**

-  **For normal mass ordering **
**  ****limit on** sin**2**2******13 ****will be 0.005 **
**  ****for no CP**
**If reversed mass ordering **
**  ****then need to run **
**  ****antineutrinos**

- Diwan

## Comparison of Some Experiments

- From NuMI Off-Axis LOI

- BNL-NUSEL
-       1-10

- 500 kT

- 100kt LA?

- 1x10-4

- 0.01

- ~0.003

- Yes...
- Yes...
- But may
- Need nubar.

- 1.0

- 2010-2012?

- 2008

- MINOS25

- 1-5

- 5kT

- 2x10-4

- 0.05

- 0-0.05

- 0.1-0.2

- Done 2010

- ~0.03

- ?
- No

## Conclusions

- It is likely that more than one will be essential to completely answer all of the questions available in a reasonable period of time.
- Take care for discovery potential beyond what we think we are after now!
- Which ones to undertake? The attraction of incremental investments certainly appears seductive... But taking a bolder step should be seriously considered and debated.