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/


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


peak

Miniboone


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 (?)


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?


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


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


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


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

2540 km

Homestake BNL

28 GeV protons, 1 MW beam power500 kT Water Cherenkov detector5e7 sec of running, Conventional Horn based beam

Diwan


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


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


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


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

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NuFact 03 5th International Workshop on Neutrino Factories & Superbeams