Super muonneutrino beam

1
Super muon-neutrino beam
nFact02 July 1, 2002 Imperial College London

• Takashi Kobayashi
• IPNS, KEK

• Contents
• Introduction
• Super-beam long baseline experiments
• Physics sensitivity
• Summary

2
Next goals of LBL experiments

• Establish 3 flavor framework (or find something
  new)
• Discovery of ne appearance (q13gt0?)
• At the same Dm2 as nm disapp. ?Firm evidence of
  3gen. mix.
• Open possibility to search for CPV
• Confirmation of nm?nt
• Appearance
• NC measurement
• Precision measurements of ocs. params.
• Dm23,q23/Dm13,q13
• Test exotic models (decay, extra dimensions,.)
• Sign of Dm2
• Search for CPV in lepton sector
• Give hint on Matter/Anti-matter asymmetry in the
  universe

3
Whats super muon-neutrino beam?
Conventional neutrino beam production
with MW-class proton beam
For high precision LBL experiments
4
Super beam LBL experiments 2nd generation
LBL experiments w/ high intensity conventional
beam

• High statistics
• Beam intensity ?100kW ? ?MW (super beam)
• AND/OR detector mass 10kt ? 1001,000kt
• Designed and optimized after the knowledge of
  Super-Kamiokande/K2K results
• Primary goal ne app. ? CPV, sign of Dm2
• Japan JHF(off-axis)?SK/HK
• FNAL Off-axis NuMI, Proton driver upgrade,
• BNL Super AGS(off-axis)??
• CERN SPL?Furejus, Off-axis CNGS

5
Next critical pathnm?ne appearance
Backgroud
Signal

• Beam intrinsic ne contamination
• Identical signature w/ signal
• Different energy distribution
• NC p0 production
• NC multi pion production

nm
ne
Single EM shower
6
Key for ne appearance experiment

• High statistics
• Small background contamination (beam)
• intrinsic ne ? short decay pipe,
• off-axis, ? less high energy tail ? less
  inelastic
• Background rejection (beamdetector)
• event topology (e?p0)
• narrow spectrum beam w/ neutrino energy
  reconstruction
• ? additional kinematical constraint
• Small systematic error on background estimation
• near/far spectrum difference
• cross section
• detector response

7
High intensity narrow band beam-- Off-axis (OA)
beam --
(ref. BNL-E889 Proposal)
nm flux
Decay Kinematics
1
2
5
1/gpq

• Increase statistics _at_ osc. max.
• Decrease background from HE tail

8
Charged current cross sections

• Inelastic
• NCp0
• multi p
• .

CCqe dominate ?1GeV Inelastic dominate ?1GeV
Backgroud
CCqe (nmn?mp)
9
Background rejection
Typical OA spectrum

• Event topology
• p0 for example,
• additional EM activity?
• vertex displacement (g flight)
• angular distribution
• intrinsic beam ne no way
• En distribution
• Signal peaked at osc. max.
• Fake ne event by p0beam ne broad

OA2deg_at_JHF
nm
ne
10
En reconstruction

• ?1GeV
• 2-body kinematics
• of dominant CCqe
• Water Ch. works well
• ?1GeV
• Inelastics (nuclear resonances) dominate
• (Fine grain) sampling calorimeter. Resolution?
• Full reconstruction of secondary particles?

11
En reconstruction ?1GeV region
?
CC quasi elastic reaction
p
CCqe
Inelastic (BG)
SK Full Det. Sim.
s80MeV(10) limited by Femi motion
Small BG
12
Syst. error far/near spectrum diff.
K2K case (MC)
FD(300m) (xLSK2/LFD2)
SK
Large(x2) effect around peak!!
Important not only for nm disappearance, but also
for sig/BG estimation for ne search
13
(super-beam) LBL experiments

• The plans are in very different phases. Most are
  in optimization phase.
• JHF-SK most advanced
• budget request submitted
• EXISITING real detector

14
JHF-Kamioka Neutrino Project
(hep-ex/0106019)
Plan to start in 2007
1GeV n beam
Kamioka
JAERI (Tokaimura)
Super-K 22.5 kt
Hyper-K 1000 kt
0.77MW 50 GeV PS
4MW 50 GeV PS
( conventional n beam)
Phase-I (0.77MW Super-Kamiokande) Phase-II
(4MWHyper-K) Phase-I ? 200
15
Principle of JHF-Kamioka project

• Intense Narrow Band Beam by off-axis.
• Beam energy is at the oscillation maximum.
• High sensitivity, less background
• 1 GeV n beam for Quasi-elastic interaction.

m events
En(reconstruct)
s80MeV
En(reconstruct) En (True) (MeV)
En (True)
16
JHF Facility
Super Conducting magnet for n beam line
JAERI_at_Tokai-mura (60km N.E. of KEK)
(0.77MW)
Construction 20012006 (approved)
Near n detectors _at_280m and _at_2km
Budget Request of the n beam line submitted
1021POT(130day) 1 year
17
Expected spectrum
ne contamination
0.21
m-decay
K-decay
Very small ne/nm _at_ nm peak
4500 tot int/22.5kt/yr 3000 CC int/22.5kt/yr
18
Detectors at near site

• Muon monitors _at_ 140m
• Behind the beam dump
• Fast (spill-by-spill) monitoring of beam
  direction/intensity
• First Front detector Neutrino monitor _at_280m
• Intensity/direction
• Neutrino interactions
• Second Front Detector _at_ 2km
• Almost same En spectrum as for SK
• Absolute neutrino spectrum
• Precise estimation of background
• Investigating possible sites

Neutrino spectra at diff. dist
1.5km
295km
280m
0.28km
19
Far Detectors
1st Phase (2007, 5yrs) Super-Kamiokande(22.5kt)
2nd Phase (201x?) Hyper-Kamiokande(1Mt)
41.4m
40m
48m 50m 500m, Total mass 1 Mton
20
USA FNAL and BNL plan

• BNL Super AGS (1.3MW, LOI submitted)
• FNAL Super NUMI (1.6 MW) or the new proton
  driver.

(hep-ex/0205040,0204037,hep-ph/0204208)
Soudan
Off-axis beams 2 detectors
Homestake
WIPP
100km
FNAL
BNL
21
OA-NuMI
A. Para, M. Szleper, hep-ex/0110032
Osc. max. _at_ 730km 1.8GeV (Dm23x10-3eV2)

• Features
• Nuclear resonance region
• ? Inelastic background
• ? Energy reconstruction?
• Too large angle? Kaon peak
• Beam goes 3.5deg downward
• ? hard to place 2nd near det. ? Far/near
  ratio?
• Para/Szlepers prescription
• using Matrix (hep-ex/0110001)

K decay
0.78deg
22
Europe SPL?Furejus
CERN
Geneve

• SPL _at_ CERN
• 2.2GeV, 50Hz, 2.3x1014p/pulse
• 4MW
• Now under RD phase

130km
40kt ?400kt
Italy
23
Detectors
Liquid Ar TPC (100kton)
UNO (400kton Water Cherenkov)
24
Physics Sensitivity
25
ne appearance in JHF-Kamioka (phase 1)
Backgrounds
9.3 events
1.8 events
11.1 events
Signal
123.2 events _at_ sin22q130.1, Dm2310-3eV2
(5 years running)
26
ne appearance (continue)
sin22qme0.05 (sin22qme ? 0.5sin22q13)
Dm2
CHOOZ
20 improvement
310-3
sin22qme 1/2?sin22q13
sin22q13lt0.006 (90 C.L.)
27
nm disappearance
1ring FC m-like
dsin22q
Oscillation with Dm2310-3 sin22q1.0
d(sin22q)
OAB-2degree
Non-QE
0.01
3?10-3
True Dm2
Reconstructed En (MeV)
dsin22q23 0.01 dDm232 lt 110-4eV2
28
Sensitivity(3s) to CPV(2nd phase)
Chooz excluded
_at_Dm313x10-3eV2
dgt14deg
dgt27deg
Preliminary
JHF1 3s discovery
29
US Super n beam

• They are studying the physics potential of
  several options, which are competitive to
  JHF-Kamioka project.

NUMI-offaxis
0.003
Ue32 1/4?sin22q13
30
Possibility to discriminate sign of Dm2 (Matter
effect)
hep-ex/0206025

• Small matter effect in JHF-SK (1GeV-295km)
• Other longer baseline projects could play
  complementary role

OA-NuMI MC study
Dm232true
Running time nmnm13 (cross sec. diff)
3s
For example, 5yrs of OA-NuMIx20kt(w/ proton
driver)
31
Summary

• Exciting topics in 2nd generation LBL
  experiments.
• ne appearance
• CPV, sign of Dm2,
• Several super-beam experiments are under
  consideration
• US, Europe and Japan
• They are in very different stages.
• Earliest beam is expected in 2007 at JHF-Kamioka
  project
• Accelerator construction started in 2001.
• Budget request for n facility submitted this year.

32
Summary (II)

• Physics sensitivity of JHF-Kamioka project
• sin2q130.006 (90CL)
• d(Dm2)?3, d(sin2q23)1
• can discover CPV if d?20o (in 2nd phase)
• Experiments are complementary each other
• JHF-Kamioka hard to see matter effect
• ? Longer baseline/higher energy experiments
• nFact will come after the (at least) 1st round of
  super-beam experiments (1020yrs)
• If sin2q13?0.01, JHF-SK may not see, but JHF-HK
  may.
• But sensitivity to CPV in JHF-HK reduces
• ? CPV in nFact?

33
Future Prospect
2002 JHFn budget requestapproval 2003 start
construction 2005 K2K final results
2007
JHF1
Hint?
201x
3s discovery
JHF2 Search q13 lt10-3 Proton decay
JHF2 CPV precision meas. q13 Proton decay
20xx
Future SuperBeam, VLBL, n-fact for very small
q13, CPV, sign of Dm2
34
(Super) Neutrino Beams
35
FNAL, BNL to Soudan
1? off-axis
Events/0.1GeV/5years/100kTon
Events/0.1GeV/5years/10kTon
x

• Water Cherenkov like Super-K

36
Far/near spectrum ratio
0.5km
Decay pipe len. LDV80m
0.28km
want near det. _at_ ?10xLDV
1.0km
1.5km
2.0km
0 1 3 5 (GeV)
37
Sensitivity for Mixing Angle
sin22qme sensitivity
JHF2-HK 1yr
38
nm ?nt confirmation w/ NC interaction

• NC p0 interaction (n N ? n N p0)
• nm? ne CC NC(0.5CC) 0 (sin22qme0)
• nm CC NC(0.5CC) 0 (maximum
  oscillation) nt
  NC
• p0 is sensitive to nt flux. Limit on ns
  (df(ns)0.1)

nm? nt
CC
nt
t
p0 e-like
D39044
nt
NC
nt
nm? ns
p0
3.5?10-3
Dm232
39
(High Intensity) Proton Accelerators
Not the construcion stage yet, but RD stage.
40
Some ideas for OA-NuMI detector(under
consideration)
SOMINOS(FeSci) SzleperVelasco
Plastic pellets RPC (A.Para)
20m
20m
5kt, 12m dia., 875planes
1m
70ton/plane
41
Super Proton Linac (SPL) _at_ CERN
Reuse some parts from LEP
Under RD phase