1. Oscillation Physics at INO
Debasish Majumdar
(On behalf of INO collaboration)
Saha Institute of Nuclear Physics
Kolkata
Sattelite workshop on INO, IITB, Mumbai, 1-2 Aug. 2005

2. India-based Neutrino Observatory
An underground facility in India for
neutrino physics
The proposed detector is an Iron CALorimeter
(ICAL) detector
ICAL consists of iron plates stacked horizontally
interleaved with glass RPC detectors

3. Purpose of INO To see the actual oscillation of neutrinos
Study of matter effects through electric charge
identification
To identify the mass hierarchy (normal or inverted)
To measure the 13 mixing angle 13
Study of CP and CPT violation
A) Study atmospheric neutrinos
B) End detector of a long base-line experiment

4. P() = 1 - sin22 sin2 [1.27 m2 (L/E)]
For 3- Flavours
cij=cos ij sij =sin ij
For 2- Flavours
P() = 1 - sin22 sin2 [1.27 m2 (L/E)]

5. Two flavour oscillation formula:
P() = 1 - sin22 sin2 [1.27 m2 (L/E)],
L in Km, E in GeV
For oscillation studies one should have
L the path-length of the 
E the energy of the  +Z d R  L
L = (R-d)cos2() +  [R2 - (R-d)2sin2()]

6. In the absence of oscillation Up-going events = Down going events
P() = 1 - sin22 sin2 [1.27 m2 (L/E)],
In the absence of oscillation
Up-going events = Down going events 
In presence of oscillation
Down-going neutrinos suffers no or negligible oscillation
[as they traverse shorter length (L)]
Up-going neutrinos traverse longer length (L) 
Oscillates effectively
plot shows oscillatory behaviour

7. Mirroring of down going events
For no oscillation
Down going 
Down going events in any direction
 Up going events from opposite direction
True L 
Detector
Due to oscillation
Up going events < down going events
in the opposite
direction
- 
Earth
+ Atm
L= mirrored L
Up going 
“Mirror” down going ’s with angle - 
consider them no oscillation standard for up going ’s at angle 
 Measure of oscillation

8. Detector Configuration
Horizontal alignment : (ICAL-H)
No. of Chambers = 8 along y axis
No. of Modules = 16 along x axis
No. of Layers = 140 along z axis
Dimension : 32m  16m  12m
Mass = 32 kTon
For 100 kTon Horizontal stacking dimension is changed as
x = 96m, y = 16m, z = 12m

9. SIMULATIONS
WITH ICAL DETECTOR
a) NUANCE event generator
Given the detector specifications and atmospheric neutrino flux
(Burtol and/or Honda) it generates neutrino events at ICAL
(product particles and their production vertex at ICAL)
b) GEANT 3.2 Simulation Code
The outputs of NUANCE are the inputs to GEANT
GEANT propagates the product particles through ICAL and
Gives as outputs, their hit points, momenta, time information etc.
c) Analyse the GEANT output

10. Case I: Oscillation incorporated inside NUANCE itself
GENERATING OSCILLATED EVENTS USING NUANCE
Output details : Event no., particle id, x, y, z, px, py, pz
Oscillation probability
P() = 1 - sin22 sin2 [1.27 m2 (L/E)],
m2 =2.0  10-3 eV2, sin22 =1
Case I: Oscillation incorporated inside NUANCE itself
Case II: From NUANCE output , prob. of each event is
calculated using the oscillation formula
Now after each event call a random number.
If prob.> Random number, then that event survives.
If prob.< Random number, then that event is ignored
Resulting Output is Oscillated Nuance Data

11. SIMULATION USING GEANT 3.2 CODE
A GEANT based simulation programme is written
A 3-D cartesian coordinate system is used with
Origin at the centre of ICAL
Z-axis pointing upwards
Detector dimensions
-1600 cm < x < cm
-800 cm < y < +800 cm
-600 cm < z < +600 cm
(32 m x 16 m x 12 m)
Magnetic Field
Bx = 0 = By, Bz = 1 Tesla
Programmes are also written to read a mapped magnetic field in
x-y plane (Bx, By, 0) and use it for GEANT simulation
Contd….

12. Output of GEANT based simulation programme
Co-ordinates of the successive hit points and their momenta at
every hit point (i.e. x,y,z, px, py, pz) of the product particles
(mainly ’s and hadrons), propagating through ICAL)
From (x,y,z) coordinates tracks (trajectories) are constructed
Trajectories are helical for charged particles (due to B) with
continuously shrinking radius due to energy loss
Y (cm)
Y (cm)
X (cm)
X (cm)

13. Finding L and E of incident  from GEANT simulated tracks
Two types of analyses
Analysis with fully contained (FC) events only
Analysis with both FC and partially contained (PC) events
L is calculated by finding the zenith (polar angle)
L = (R-d)cos2() +  [R2 - (R-d)2sin2()]
 is calculated from the track and it’s projection on x-y plane
Energy E is calculated in two ways
FC events
From average path length
FC + PC events
Using the track geometry
(bending due to magnetic field B)

14. Track Selection FC events
i) A neutrino event must have a track with 12 hits or more
ii) The event has no more than two tracks
FC + PC events
Number of hits > 9
Zenith angle cuts
L/E Resolution
We define Resolution function in terms of
(L/E)reso = {(L/E)true – (L/E)ex}/(L/E)true
Where,
L/E(true) : Parameter estimated from the NUANCE output only ()
L/E(exp) : Parameter estimated after passing through GEANT

15. Up/Dn vs L/E plot showing oscillation

16. Up/Dn vs L/E plot showing oscillation

17. Resolution Plots

18. Resolution Plots

19. Resolution Plots

20. Extraction of oscillation parameters through 2 analysis
The 2 is defined as,
2= {[(Up/down)theory – (Up/Down)Expt.]/Error}2
Theory:
Data obtained from NUANCE output folded with resolution.
Expt.:
Results obtained from GEANT simulation.

21. Contour Plot

22. Contour Plot

23. Oscillation Physics at INO with 3 ’s
(Three mixing angles and two mass square differences)
INO will address
Observance of oscillation and precise measurement of oscillation
parameters (study of matter effects)
Sign of
Determination of
Probing CP violation
STUDY
A) Atmospheric Neutrinos
B) Neutrinos from neutrino factories

24. 3
Direct (Normal) hierarchy
atm
32 > 0 2
solar
ij = mij 1 2
solar 1
atm
Inverted hierarchy
32 < 0 3

25. For 32  0, 
For neutrinos 
For anti-neutrinos
For 32  0, just the reverse

27. Determination of sign of 32
(From matter induced asymmetry)
AN is different for normal mass
hierarchy (32 > 0) and inverted
mass hierarchy (32 < 0)

28. Probing neutrino beam from neutrino Factories
( ICAL as end detector of long baseline experiment)
Beam from  storage rings with long straight sections
Intense, high luminosity neutrino beams from
 decaying in the straight section ,
Look for wrong sign 
Sign of 32
Determination of 13
Probing CP violation in the leptonic sector

29. PUSHEP Magic baseline ~ 7250 km (No CP) Rammam JHF (4828) JHF (6556)
CERN (6871)
CERN (7145)
FERMILAB
(10480)
FERMILAB
(11300)
Magic baseline ~ 7250 km
(No CP)

30. Wrong sign  events vs 32 For small 13 and 32 > 0 e  enhanced
Baseline from JHF
(A~ E/ 32)

31. The achievable sin13 at INO vs threshold energy of  detection

32. The ratio of wrong sign  events and opposite sign  events for the
storage ring vs base length
Probing CP vs

33. Discussions 1) INO has the potential to measure oscillation dip
and the oscillation parameters
2) ICAL at INO is capable of probing the measure of 13
and sign of 23 from atmospheric neutrinos
3) ICAL at INO can be a very effective far end detector for
long baseline experiments
4) With its charge discrimination capability ICAL at INO
can be very efficient to determine not only oscillation but also
mixing angle 13 and the mass hierarchy
(thus substantiating the atmospheric neutrino measurements)
And most importantly
5) Probing the CP violation-the holy grail of Physics in the lepton sector

34. INO marches ahead
Have a good day