NuFact 03 5th International Workshop on Neutrino Factories & Superbeams
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Transcript of NuFact 03 5th International Workshop on Neutrino Factories & Superbeams
Summary of Nufact-03 Alain Blondel
NuFact 03 5th International Workshop on Neutrino Factories & Superbeams
Columbia University, New York 5-11 June 2003
Highlights and personnal impressions
http://www.cap.bnl.gov/nufact03/
Summary of Nufact-03 Alain Blondel
first results from miniboonefirst results from MUSCAT!theta13 prospectives (reactor proposals!) the issue of degeneraciesbeta beam getting close in performance to neutrino factory?!Nufact: death of bow-tie
machine part: MICE strongly recommended – in approval pathstatus of target status of RF cavity studiesstatus of accelerator design FFAG!!!! Cooling ring!!!!to cool or not to cool?cost saving hopes
WORLD STUDY III
synergies: emphasis on low energy muon and high intensity physics
personnal reflexions:Europe’s strengthstwo avenues for Europe: when should we chose?
NUFACT03 Highlights
Summary of Nufact-03 Alain Blondel
peak
Miniboone
Summary of Nufact-03 Alain Blondel
MUSCATan important experiment to re-measure multiple scattering for low Z materials (discrepancies between theories and theory vs expt)engineering run 2000… several teething problems2. new measurements in spring 2003 at Triumf with many improvements (sci-Fi tracker!)
Short LH2 empty
Short LH2 full
Long LH2 full
Results…….Results…….
2003 Physics run all went very well–46M events taken; LH2 as well as solid targets–First look at data: very good; Analysis just starting
First results: ENG meeting 9th July (?)
Summary of Nufact-03 Alain Blondel
J Louis
approved (MINOS, OPERA, ICARUS) programmeon approval path (J-PARC SK) will lead to improvement vs CHOOZ by factor 2-3 (MINOS, ICARUS+OPERA with tau optimized beam) by factor 5 specially optimized L.E beam for ICARUSby factor 20 J-PARC SK
what else?
Summary of Nufact-03 Alain Blondel
Superbeam possibilities
1. J-PARC SK (2008 onwards) J-PARC HK (1 Mton) will not begin excavation before results from J-PARC SK are obtained 2011? also hopes to increase intensity from 0.7 MW to 4 MW.
2. Off-axis NUMI beam exists with required flexibility detector design in progress – will lead to a LOI in the fall near detector. (how can this be in time to be competitive???)
2’. CNGT: need beam (not CNGS) and detector. Detector viability? (single wall is ‘technologically risky’)
+ interesting: what is the physics of an off axis at the second osc. max? - no near detector NB similar idea had been put forward by Susuki in 2000 in an immersed super-tanker. both 2 and 2’ are dedicated detectors that can do nothing else as such. (CNGT could be re-deployed as km3 detector)
3. BNL homestake mine 4. SPL + beta beam Frejus a very serious contender iff beta beam can perform as advertised. (almost a neutrino factory!) ecavation could start in 2008 (better get our act together!) the most consistent scheme for a CERN based effort! support SPL + propose the Fréjus International Laboratory
Summary of Nufact-03 Alain Blondel
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 levelWell known and understood detector technologiesPrimarily the engineering challenge of (cheaply) constructing a very massive detector
How massive??
50 kton detector, 5 years run => 10% measurement if sin2213 at the CHOOZ limit, or 3 evidence if sin2213 factor 10 below the CHOOZ limit (normal hierarchy, =0), or Factor 20 improvement of the limit
Para
Summary of Nufact-03 Alain Blondel
NuMI Off-axis50 kton, 85% eff, 5
years, 4x1020 pot/y
JHF to SKPhase 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=2.8x 10-3,
NuMI/JHF)867.3 307.9 302 123
FOM (S/sqrt(B)) 40.7 26.2
Para
Summary of Nufact-03 Alain Blondel
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
Summary of Nufact-03 Alain Blondel
BNL Homestake Super Neutrino Beam
2540 km
Homestake BNL
28 GeV protons, 1 MW beam power500 kT Water Cherenkov detector5e7 sec of running, Conventional Horn based beam
Diwan
Summary of Nufact-03 Alain Blondel
Advantages of a Very Long Baseline
DISAPPEARANCE
0
50
100
150
200
250
0 1 2 3 4 5 6 7 8 9 10
Reconstructed Energy (GeV)
BNL-HS 2540 km
sin2223 = 1.0
m2 32 = 2.5e-3 eV2
1 MW, 0.5 MT, 5e7 sec
No oscillations: 13290 evts
With oscillations: 6538 evts
Background: 1211 evts
neutrino oscillations result from
the factor sin2(m322 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
m322 to be precisely measured
by a wavelength rather than an amplitude (reducing systematic errors)
Diwan
Summary of Nufact-03 Alain Blondel
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 sin2213 can be made (the
current experimental limit is 0.12)
for most of the possible range of
sin2213, a good measurement of
13 and the CP-violation parameter
CP can be made by the VLB
experimental method
Diwan
Summary of Nufact-03 Alain Blondel
e Appearance Measurements (Cont.)
even if sin2213 = 0, the current
best-fit value of m212 = 7.3x10-5
induces a e appearance signal
the size of the e appearance signal
above background depends on the
value of m212; the figure left
indicates the range of possible
measured values for the e
yields above background for various assumptions of the final value of
m212
Diwan
Summary of Nufact-03 Alain Blondel
very long baseline proposal (BNL homestake mine)
-- interest: CP violation and sign m213 from 1st to second peak comparison
-- energy dependence helps extracting the physics
criticisms: 1. very large mass required to reach decent sensitivity (1/L2 dependence hurts)
2. possibility of detecting e signal at > 1-2 GeV seriously criticized