n e

Appearance Experiment with Off-axis Detector in a NuMI Beam • Physics • Off-axis NuMI Beam • Detector Issues • Off-axis Experiments: evolution of the accelerator and detectors • Scenarios

February 15, 2003 Adam Para

Neutrinos vs Standard Model

Whereas • There is a major effort to complete the Standard Model (Higgs search) • There is a broad front of experiments looking for possible deviations from the Standard Model (SUSY searches, B physics experiments, g-2, EDM, …) The first evidence for physics beyond the standard model is here: • Neutrino mass and oscillations Where does it lead us?

• Just an extension (additional 9? 7? Parameters) ?

• First glimpse at physics at the unification scale ? (see-saw??) • Extra dimensions?

• Unexpected? (CPT violation ???)

The outstanding questions in neutrino physics, AD2003

• Neutrino mass pattern: This ? Or that?

• Electron component of n 3

(sin

2

2

q 13

)

n n

e

 n   

B B



B B B B s B B

n n n 2 • Complex phase of s sector   CP violation in a neutrino (?) baryon number of the universe • mixing angle q 23 :

sin

2

2

q 23

= 1 –

e New symmetry? Broken?

The key :

n   n e

oscillation experiment

P

( n   n

e

) 

P

1 

P

2 

P

3 

P

4

P

1  sin 2 q 23 sin 2 q 13    13

B

   2 sin 2 2

P

2  cos 2 q 23 sin 2 q 12

P

3 

P

4

J

cos  

J

sin   12

A

 12

A

 12

A

2 sin 2

AL

2    13

B

   cos  13

L

sin 2    13

B

   sin  13

L

sin 2

AL

2 sin

AL

sin 2 2 2  

ij



m ij

2 ; 2

E

n

A

 2

G n F e

;

B



J

 

A

  13 cos q 13 ; sin 2 q 12 sin 2 q 13 sin 2 q 23

P



f

(

, ,sgn(



m

2 13

)

,  2

m

12 ,  2

m

13 2 , sin 2 q 12 , 2 sin 2 q 23

E

) 3 unknown, 2 parameters under control, neutrino/antineutrino

sin 2 2

q

13

Anatomy of Bi-probability ellipses

~sin  ~cos   Minakata and Nunokawa, hep-ph/0108085 Observables are: •P •P Interpretation in terms of sin 2 2 q 13 ,  and sign of  m 2 23 depends on the value of these parameters and on the conditions of the experiment: L and E Rates differ by factor of 4 for the same sin 2 2 q 13

Mass Textures and

q 13

Predictions, Examples

Texture

m

        1 1  e 2 2 1  1 2 1   2 2 1 1 1  e 2 2 2 e       2 Degenerate neutrinos, spontaneously broken flavor SO(3) q 13 

m

2

sun

 2

m atm

 1/ 2  0 sin 2 2 q 13 ~0.064

perturba tions e  e 

m

        1 0 0 0 1 0

m

    1 1 0 0   1  

r

 1 1 1    1 1 1 1 1 1         

m

n  1 1      

m

   e e e 1   1   e 1     1   Degenerate neutrinos, democratic mass matrix Inverted hierarchy Normal hierarchy   

m m



e

 1/ 2  ~0.019

 

m

2

sun

 2

atm



m

2

sun

 2

atm

     2

m sun

 2

atm



m

2

sun

 2

atm

 1/ 2  1/ 3 ~0.001

<<0.001

~0.064

~0.26

    Altarelli,Feruglio, hep-ph/0206077  0

Off-axis NuMI Beams: unavoidable byproduct

" •Beam energy defined by the detector position (off-axis, Beavis et al) •Narrow energy range (minimize NC-induced background) •Simultaneous operation (with MINOS and/or other detectors) •~ 2 GeV energy : • Below tau threshold • Relatively high rates per proton, especially for •Baselines 700 – 1000 km antineutrinos •Matter effects to amplify to differentiate mass hierarchies

Oscillation probability vs physics parameters

Parameter correlation: even very precise determination of P n leads to a large allowed range of sin 2 2 q 23  statistics antineutrino beam is more important than improved

n e

Appearance Counting Experiment: a Primer

P

 e  #

of dE

 n n

e cand

.

 en

e beam

 n

CC E P

n   n

e

 

NC

This determines sensitivity of the experiment

sens P

90%

CL

 e 

dE

 n

1.28

e n

e beam

 n

CC

 

N C P

n   n

e E

)

Systematics: •Know your expected flux •Know the beam contamination •Know the NC background*rejection power (Note: need to beat it down below the level of n e beam only) •Know the electron ID efficiency component of the

Sources of the

n e

background

n e / n  ~0.5%

All K decays

At low energies the dominant background is from  +  e + + n e + n  decay, hence  K production spectrum is not a major source of systematics  n

e

background directly related to the n  spectrum at the near detector

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 n 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 sin 2 2 q 13 at the CHOOZ limit, or • 3  evidence if sin 2 2 q 13 factor 10 below the CHOOZ limit (normal hierarchy,  =0), or • Factor 20 improvement of the limit

Signal and background

Fuzzy track = electron Clean track = muon (pion)

Background examples

NC p 0 - 2 tracks n  CC - with p 0 - muon

Beam-Detector Interactions

• Optimizing beam can improve signal • Optimizing beam can reduce NC backgrounds • Optimizing beam can reduce intrinsic rather than individual components n e background – Easier experimental challenge, simpler detectors • # of events ~ proton intensity x detector mass – Allocate the re$ources to maximize the product,

A Quest for NuMI Proton Intensity

Protons per Booster batch Batches available for MINOS Relative Efficiency per batch Protons per MI Cycle MI Cycle Period (seconds) Beam Power (MW) NuMI Running time per year (seconds) Protons per year 1998 Letter from "Now" John Peoples 7.00E+12 5 1 3.50E+13 4.50E+12 5 1 2.25E+13 2005 "current plan" 5.00E+12 5 1 2.50E+13 2005 possible 5.50E+12 10 0.7

3.85E+13 2008 possible 6.00E+12 10 0.9

5.40E+13 2010 Recycler Stacking 2010+ Proton Linac 6.50E+12 10 0.95

6.18E+13 1.00E+14 1.9

0.35

2.00E+07 3.68E+20 2.5

0.17

1.50E+07 1.35E+20 1.9

0.25

1.80E+07 2.37E+20 2.22

0.33

1.80E+07 3.12E+20 1.72

0.60

2.00E+07 6.28E+20 1 1.17

1 1.90

2.00E+07 2.00E+07 1.24E+21 2.00E+21 Nominal “NuMI year” NuMI Intensity Working Group, D. Michael/P. Martin

Two phase program Phase I (~ $100-200 M, running 2007 – 2014)

• 50 kton (fiducial) detector with e ~35-40% • 4x10 20 protons per year • 1.5 years neutrino (6000 n  CC, 70-80% ‘oscillated’) • 5 years antineutrino (6500 n  CC, 70-80% ‘oscillated’) Phase II ( running 2014-2020) (D. Harris) • 200 kton (fiducial) detector with e ~35-40% • 20x10 20 protons per year (new proton source?) • 1.5 years neutrino (120000 n  CC, 70-80% ‘oscillated’) • 5 years antineutrino (130000 n  CC, 70-80% ‘oscillated’)

Conclusions

    Neutrino Physics is an exciting field come for many years to Most likely conditions will be required to unravel the underlying physics several experiments with different running beam is uniquely matched Fermilab/NuMI that could be available to this physics in terms of beam intensity, flexibility, beam energy, and potential source-to-detector distances Important element of the the next 20 years HEP program in the US for

Project Evolution (so far)

• May 2002: Workshop ot Fermilab, 140 people • June 2002: LOI submitted • September 2002: All about NuMI – UCL London, 27 participants • Now: Argonne- Athens Berkeley - Boston - Caltech - Chicago College de France - Fermilab -Harvard London - LSU - MIT - MSU – ITEP Minnesota-Crookstone Minnesota-Duluth -Minnesota-Minneapolis - TUM-Munchen NIU - Ohio-Athens - Oxford - Pittsburgh - Princeton Rochester - Rutherford - Sao Paulo - Stanford Lebedev - UC Stony Brook Sussex- Texas-Austin - TMU-Tokyo - Tufts - UCLA - Virginia Tech - York-Toronto(115 physicists) ( red – joined since LOI submission) • Expression of interest from several more institutions • January 2003 : Detector Workshop at SLAC ~65 people, narrow technologies to sampling calorimeters • April 2003: Detector Workshop at Argonne, compare gas/scintillator detector designs

What size collaboration is needed to construct and do physics with the detector? Do the collaborators have other, overlapping obligations ?

The detector is huge but simple. The size of the technical/engineering staff is the most critical for for the timely design/construction/installation of the experiment. At present there are some 45 institutions, 140 physicists involved. More groups are expressing their interest. While most people have, to a varying degree, other obligations at this time, the strength of the collaboration already now is sufficient to ensure a success of the experiment.

We expect a significant influx of interested parties once the project becomes more real.

What is the timeline/schedule for the Off-Axis beam and detector?

NuMI beam: start operation spring 2005 (Reminder: a major investment of US High Energy Physics) Detector construction: schedule driven by external factors. An optimistic scenario:  Oct 03 – proposal     fall 03 - spring 04 initial reviews, cost and design validation summer 04 - approval 04 - 05 construction of a near detector, preparation of infrastructure for mass production 05 site selection, start site preparation    06 start construction 07 start data taking with adiabatically growing detector 08 complete construction

What is the estimated project cost including the beam and detector? Please give the basis for the cost estimate.

Beam exists. Three-fold intensity upgrades is estimated to cost $45M.Based of on the work of the joint Beams Division/NuMI/MINOS working group.

A committee dedicated to the review, validation and specific recommendation is being formed.

Detector costs are based on the existing experience of MINOS and other experiments, like BELLE, using the same technology. An estimated detector cost is in the range of 1-3 M$ per kton. Large cost savings can be accomplished by optimization of the longitudinal sampling. The current cost estimates assume 1/3 radiation length sampling which provides a very comfortable background rejection. [Need a complete validated design to have a credible cost estimate]

How does the Off-Axis Detector fit into the evolving world picture, especially the JHF-SuperK experiment, in terms of adding an important new contribution to our understanding of particle physics?

Determination of the neutrino mixing matrix, mass hierarchy, possible studies of CP violation will require multiple precise measurements taken under different conditions (distance, energy, matter effects).

In principle, the NuMI beam provides enough flexibility to complete the entire program, given a sufficienty large number of massive detectors located at different positions. This would be a very long, and very expensive program. Parallel measurements at JHF, with no matter effects, will help to extract the interesting physics parameters in a shorter (still probably very long) time scale. A possible new reactor experiment measuring/further limiting q 13 would of interest.

Determination of mass hierarchy: complementarity of JHF and NuMI

Combination of different baselines: NuMI + JHF extends the range of hierarchy discrimination to much lower angles mixing angles Minakata,Nunokawa, Parke

Two body decay kinematics

At this angle, 15 mrad, energy of produced neutrinos is 1.5-2 GeV for all pion energies  very intense, narrow band beam ‘On axis’: E n =0.43E

p

p L

 

(

p

*

cos

q *  

E

*

)

p T



p

*

sin

q *