India-based Neutrino Observatory (INO)ino/Talks/ino_whepp.pdf · India-based Neutrino Observatory (INO) Physics Prospects and Status Report D. Indumathi Institute of Mathematical

India-based Neutrino Observatory(INO)

Physics Prospects and Status Report

D. Indumathi

Institute of Mathematical Sciences, Chennai

([email protected])

For the INO Collaboration

(http://www.imsc.res.in/∼ino)

WHEPP 8, IIT Bombay, Jan 8 2004 – p.1/42

Outline of talk

Status report

The INO Collaboration

Motivation: Atmospheric neutrinos and oscillationphysics

Choice of detector/source

The ICAL detectorRPCs, the active detector elementsThe magnet designPhysics Simulation of ICAL

Choice of detector location: Site Survey


Outline of talk

Status report







Outline of talk

Status report







Outline of talk

Status report







Outline of talk

Physics Prospects

Atmospheric neutrinos

Oscillation physics with atmospheric neutrinosDetailed analysis at ICAL without magnetic fieldDetailed analysis at ICAL with magnetic field

Neutrino-factory neutrinos

ICAL or upgraded-ICAL as far-end detector fornu-factory

Non-oscillation physics

Ultra high energy cosmic rays, “Kolar events”, . . . ✘


Outline of talk

Physics Prospects








Outline of talk

Physics Prospects








Status Report



Phase I : Around 2 years (On-going)

Detector R & DPhysics StudiesSite SurveyHuman resources development

Phase II : Construction of the detector

Detector Possibilities

Magnetised iron with RPCs or glass spark chambers

Alternate design ✘

Should be an international facility




















Physics goals of analysis

Stage I:Studyoscillation patternin atmosphericneutrino events.

θ

θ

down

up

L

(Pietropicchi)


The difficulty and the hope


Choice of Neutrino Source and detector

Neutrino Source

Need to cover a large L/E range

Use atmospheric neutrinos as source

Large L range; also large E range

Need good resolution in both E and L (that is, in zenithangle θz)

Detector choice

Should have large target mass: 30 kton, 50 kton,100 kton . . .

Good tracking and energy resolution

Good directionality (≤ 1 ns time resolution)

Good charge resolution (for Stage II)

Ease of construction

Use (magnetised) iron as target mass and RPC as activedetector element

Note: Is sensitive to muons only


Choice of Neutrino Source and detector

Detector choice

Should have large target mass: 30 kton, 50 kton,100 kton . . .

Good tracking and energy resolution

Good directionality (≤ 1 ns time resolution)

Good charge resolution (for Stage II)

Ease of construction

Use (magnetised) iron as target mass and RPC as activedetector element

Note: Is sensitive to muons only


The ICAL detector


The active detector elements: RPC

RPC Construction: Float glass, graphite, and spacers

at TIFR . . .



RPC Principles of operation: Streamer vs Spark mode

at TIFR . . .



at TIFR . . .


RPC Efficiency studies

Using different combinations of gas


RPC Time resolution

at TIFR


Other issues w.r.t RPC R & D

RPC timing

RPC charge distribution

Mean charge vs voltage (seen to be linear)

RPC noise

Gas composition (C2H2F4, C4H10, Ar, Isobutane (8%))

RPC Cross talk (as a function of gas mixture)

Gas mixing


Magnet studies


Detector and Physics Simulation

NUANCE Event generator: Generates atmosphericneutrino events inside ICAL

GEANT Monte Carlo package: Simulates the detectorresponse for the neutrino event

Event Reconstruction: Fits the “raw data” to extractneutrino energy and direction

Physics Performance: Analysis of reconstructed eventsto extract physics


Simulations: Status report

Neutrino Generator

– Nuance: ICAL configuration with 3-flavour oscillationcode (D. Casper)

– Local: (HRI)

– (Neugen : H. Gallagher) ✘ Not used so far

One-line status summary:

programs in place and being tested; “data” beinganalysed.



Detector Simulation

– Geant (3.2.1 Fortran) program in place; now withmagnetic field map as well.





Track Reconstruction using Fortran/ROOT in C++

– Without magnetic field: program fits muons to straightlines, with energy loss; still to be refined.

– With magnetic field: program fits muons to helicaltrajectory, with energy loss; still to be refined.

– Hadron hit reconstruction: to be refined.








Site survey: PUSHEP

PUSHEP in Nilagiris, near Ooty (Masinagudi)


Site Survey: Rammam

Rammam in Darjeeling District


Physics Prospects


Physics with Atmospheric Neutrinos

Simplified ICAL detector geometry encoded in Nuancegenerator.

Events are generated using HONDA flux with someinput oscillation parameters δ23, θ23, and θ13 = 0 (ICALmay not be sensitive to 1-3 mixing).

Quasielastic, resonant, DIS events, roughly in1/3 : 1/3 : 1/3 ratio

Analysis ONLY of 5 year CC events with µ in the finalstate (electron CC events mostly lost); typicallyinteresting events have E > 1–2 GeV.

MAJOR ISSUE, YET TO BE STUDIED: Mis-identification of pionsas muons from NC as well as a subset of CC events.

Recall: ICAL geometry is similar to that of MONOLITH.WHEPP 8, IIT Bombay, Jan 8 2004 – p.20/42

Physics Analysis (2-flavour)

➢ Main goal: Study oscillation pattern in atmosphericneutrino events. θ

θ

down

up

L

(Pietropicchi)

up ratedown rate

= Pµµ = 1 −sin2 θ23

2

(

1 − R cos 2.54 δ23

L

E

)

,

Resolution function is given by the Lorentzian:

R(x = L/E) =1

π

(

σ

σ2 + (x − x0)2

)

;

σ is the resolution in L/E of the ICAL detector.

So, analysis needs a knowledge of this resolution function.


Physics Analysis (2-flavour)

up ratedown rate

= Pµµ = 1 −sin2 θ23

2

(

1 − R cos 2.54 δ23

L

E

)

,

Resolution function is given by the Lorentzian:

R(x = L/E) =1

π

(

σ

σ2 + (x − x0)2

)

;

σ is the resolution in L/E of the ICAL detector.

So, analysis needs a knowledge of this resolution function.


Energy Resolution

1

10

100

1000

10000

100000

1 10 100

Energy (GeV)

Energy distribution (neutrinos and muons)

0

10

20

30

40

50

60

70

80

90

-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1

even

ts

(E(nu)-E(mu))/E(nu)

Energy resolution

• Energy resolution with muons alone and includinghadrons as well.

• Eµ ∼ 0.7Eν


Nuance output

400

500

600

700

800

900

1000

1100

1200

1300

1400

-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1

cos(theta)

Zenith angle distribution (neutrinos)

200

300

400

500

600

700

800

900

1000

-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1

cos(theta)

Zenith angle distribution (muons)

Neutrinos (left) Muons (right)with oscillations . . . . . . . . . . . . without oscillations


Analysis of GEANT-processed events

The Nuance events were generated with some startingoscillation parameters (δ23 and θ) for the neutrino fluxes.

The CC events containing muons are passed throughthe GEANT program to get a pattern of hits in thesimulated ICAL detector.

The hits are recontructed to get Eµ, θµ, Ehad.

The relevant resolutions including R are studied.

R is used to fit the oscillation pattern in thereconstructed ratio of up/down events.

The fit results in estimates of the oscillation parameters.

This determines the sensitivity of the detectorconfiguration to the oscillation parameters.


WITHOUT Magnetic Field

E & L distributions from reconstructing muon tracks in ICALdetector (hadron contribution not included here).

0

5

10

15

20

25

30

0 5 10 15 20 25 30

Efit

Emu

0

2000

4000

6000

8000

10000

12000

14000

0 2000 4000 6000 8000 10000 12000 14000

Lfit

Lmu

Left: Efit from hit reconstruction vs. Eµ from Nuance

Right: Lfit from hit reconstruction vs. Lµ from Nuance


L/E Resolution

0

100

200

300

400

500

600

-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1

Eve

nts

(L/E (mu) - L/E(fit))/ L/E (mu)

Resolution obtained, in the absence of magnetic field:

∆L

E= 0.18

L

E


Physics analysis with Geant events

• Oscillation Parameters: δ23 = 3 × 10−3 eV2; sin2 2θ23 = 1.0

• Resolution function: σ = 0.18L/E

δ23 = (3.3+0.3−0.6) × 10−3 eV2 (3.0) NEW! since INSA meeting,

sin2 2θ23 = 0.98+0.02−0.07 (1.0) New Delhi, Nov 03


L/E Resolution with magnetic field

histoEntries 0Mean -0.1597RMS 0.3665

-2 -1.5 -1 -0.5 0 0.5 1 1.5 20

20

40

60

80

100

120

140

160

180

200

220

histoEntries 0Mean -0.1597RMS 0.3665

sigma=0.43

mean=-0.19

L/E Resolution for 5 yrs

h1Entries 1827Mean -0.09601RMS 0.4524

-2 -1.5 -1 -0.5 0 0.5 1 1.5 20

20

40

60

80

100

120

140

160

180h1

Entries 1827Mean -0.09601RMS 0.4524

sigma=0.30

mean=-0.13

L/E(mu) Resolution for 5 yrs

L/E resolution from reconstruction (left); muon only (right).Resolution obtained, with magnetic field:

∆L

E= 0.215

L

E.

Program has since been improved


Comments on resolutions

The worst data is at small L/E (small number ofevents.) Use of magnetic field improves the event ratehere.

Sensitivity to this small L/E region still to be studied.

One possibility is to look at vertical planes of iron.

Various refinements in progress.




















Physics Results with Nuance

Nuance → Geant → Reconstruction → Analysis formsthe complete route from simulation to analysis.

Detailed studies only without magnetic field so far;others in progress. Expect results to improve withmagnetic field.

Have used the ICAL resolution function obtained aboveto analyse the Nuance output.

Here the route is Nuance → Analysis,that is, events are directly analysed without passingthrough detector and reconstructing hit pattern soreconstruction efficiency = 1 instead of 0.4.

Analysis done for different input values of oscillationparameters, δ23 and sin θ23.






























δ = 2 × 10−3 eV2

1 2 3 40

100

200

1 2 3 40

0.5

1

1.5

0.8 0.9 1


δ = 3 × 10−3 eV2

1 2 3 40

100

200

1 2 3 40

0.5

1

1.5

0.8 0.9 1


δ = 5 × 10−3 eV2

1 2 3 40

100

200

1 2 3 40

0.5

1

1.5

0.8 0.9 1


δ = 8 × 10−3 eV2

1 2 3 40

100

200

1 2 3 40

0.5

1

1.5

0.8 0.9 1


Physics goals of analysis II

Stage II: Neutrino factories and INO (ICAL++)

Burning issue in neutrino physics: is the 1-3 mixingangle zero or not? If sin θ13 6= 0, can look for

A determination of sin θ13 itself

sign of the (23) mass-squared difference δ32 = m23 −m2

2

CP violation through a CP violating phase δ that occursin the mixing matrix when there are three activecoupled neutrino species.







2








2








2



INO as a far-end detector

INO (ICAL++) as a far-end detector for long baselineexperiments

Large L means large E (20 GeV or more), for seeinginteresting oscillation phenomena

Such a neutrino beam is far off into future, but lots ofwork going on (see neutrino oscillation industryweb-page)












Stage II: Inputs

Muon detection threshold = 2 GeV

Muon energy resolution = 5%.

All measurements involve wrong sign muon detection:low backgrounds

Beam has νe and νµ (or other way).

νµ → µ (detector)νe (beam) → νµ (oscillation)νµ (osc-beam) → µ (detector)

Result: wrong sign muon (10/kton = signal)


Stage II: Inputs








Stage II: Inputs








Stage II: Inputs








Stage II: Inputs





νµ → µ (detector)

νe (beam) → νµ (oscillation)νµ (osc-beam) → µ (detector)



Stage II: Inputs





νµ → µ (detector)νe (beam) → νµ (oscillation)

νµ (osc-beam) → µ (detector)



Stage II: Inputs








Stage II: Inputs








Reach of sin θ13

JHF to Rammam Fermilab to PUSHEP

0.016

0.018

0.02

0.022

0.024

0.026

0.028

0.03

0.032

0.034

0.5 1 1.5 2 2.5 3

sinθ

13

Eµth (GeV)

Eµ+beam = 50 GeV

32 kT-yr

100 kT-yr

50 kT-yr

1019 µ decays/yr.

JHF - RAMMAM

0.0035

0.004

0.0045

0.005

0.0055

0.006

0.0065

0.007

0.0075

0.5 1 1.5 2 2.5 3

sinθ

13

Eµth (GeV)

Eµ+beam = 20 GeV

32 kT-yr

50 kT-yr

1021 µ decays/yr.

FERMILAB - PUSHEP

sin θ13 reach for different muon threshold energies.


Sign of δ23 vs wrong sign µ

JHF to Beijing, Rammam and PUSHEP

0

20

40

60

80

100

120

140

160

180

-0.004 -0.002 0 0.002 0.004

Num

ber o

f µ- /5

0 kT

-yr.

∆m213 eV2

Eµ+beam = 20 GeV

1019 µ decays/yr.

CHINA

PUSHEP

RAMM

AM


CP violation: δ vs L

JHF to Rammam and PUSHEP

0.01

0.1

1

10

100

5000 6000 7000 8000 9000 10000 11000

N(µ

+ )/N(µ

- )

L (Km.)

sinθ13 = 0.1 ∆m223 < 0

∆m223 > 0

Eµ+beam = 50 GeV

1021 µ decays/yr.

50 kt x (1 + 1) yrs.

FermiLab to Rammam and PUSHEP


Outlook

The ICAL detector

Proof-of-principle working of RPC shown

Accelerator neutrino programme:ICAL++, with suitable beam from future nu-factory, issensitive to sin2 2θ13, sign of δ23, and CP phase.JHF-PUSHEP baseline is near magic: may provideclean separation of matter and CP violation effects.


Outlook

The ICAL detector

Magnet studies under-way



Outlook

The ICAL detector

Hence detector prototype ready for construction



Outlook

The ICAL detector

Site survey: two possible sites, both seem good options



Outlook

The ICAL detector

Simulations: programs in place, need refining andtesting.

Atmospheric neutrino programme:ICAL sensitive to oscillation parameters to betteraccuracy than current Super-K.Also, may have the edge on MINOS if δ23 is smallerthan expected. Not sensitive to 1–3 mixing angle.



Outlook

The ICAL detector

Simulations: programs in place, need refining andtesting.

Atmospheric neutrino programme:ICAL sensitive to oscillation parameters to betteraccuracy than current Super-K.Also, may have the edge on MINOS if δ23 is smallerthan expected. Not sensitive to 1–3 mixing angle.



Outlook . . .


MoU in place with several Institutes funded/aided by theDAE

Stage I studies with atmospheric neutrinos almostcomplete; Stage II with neutrinos from nu-factory to bestudied in more detail

Feasibility study in full swing; expect report by Janend/Feb 2004

The outlook looks good!

This is a massive project:

Looking for active collaboration both within India andabroad


Outlook . . .









Outlook . . .









Outlook . . .









Outlook . . .









Documents

India-based Neutrino Observatory (INO)ino/Talks/ino_whepp.pdf · India-based Neutrino Observatory (INO) Physics Prospects and Status Report D. Indumathi Institute of Mathematical