The Gran Sasso laboratory and the neutrino beam from CERN Eugenio Coccia [email protected]

Erice 2 september 2006

Content • The Gran Sasso Laboratory • Neutrino physics activity • The Cern to Gran Sasso neutrino beam • First events • Perspectives

Underground Laboratories

Very high energy phenomena, such as proton decay and neutrinoless double beta decay, happen spontaneously, but at extremely low rates. The study of neutrino properties from natural and artificial sources and the detection of dark matter candidates requires capability of detecting extremely weak effects. Thanks to the rock coverage and the corresponding reduction in the cosmic ray flux, underground laboratories provide the necessary low background environment to investigate these processes. These laboratories appear complementary to those with accelerators in the basic research of the elementary constituents of matter, of their interactions and symmetries.

LABORATORI NAZIONALI DEL GRAN SASSO - INFN Largest underground laboratory for astroparticle physics

1400 m rock coverage cosmic µ reduction= 10–6 (1 /m2 h) underground area: 18 000 m2 external facilities easy access 756 scientists from 24 countries Permanent staff = 70 positions

Research lines • Neutrino physics (mass, oscillations, stellar physics) • Dark matter • Nuclear reactions of astrophysics interest • Gravitational waves • Geophysics • Biology

LNGS most significant results with past experiments Evidence of neutrino oscillation GALLEX / GNO - solar ν MACRO - atmospheric ν

Unique cosmic ray studies EAS-TOP with LVD

ν beam Gravitational Waves Lisa test

CERN: OPERA

from

Fundamental physics VIP PRESENT EXPERIMENTS ββ decay and rare events Cuoricino CUORE; GERDA Solar ν Luna Borexino

Dark Matter DAMA/LIBRA; CRESST WARP; Xenon test ν from Supernovae LVD Borexino ICARUS

Occupancy HALL B LISA

HALL C MI R&D

XENON

Borexino

ICARUS HALL A BAM - OPERA

OPERA

LVD DAMA/LIBRA LUNA2

GERDA

VIP

CRESST

LOW ACTIVITY LAB

CUORE CUORICINO

WARP

GENIUS-TF

2004 - 2005 - 2006 Important safety and infrastructures upgrade of the Laboratory

• Floor waterproofing • Upgrade of the ventilation system • Realization of containment basins • Upgrade of the cooling capability • Safety measure for the drinkable water • Upgrade of the electrical power

LVD Large Volume Detector

Collab.: Italy, Brazil, Russia, USA, Japan

Running since 1992

1000 billions ν in 20s from the SN core Measurement of neutrinos spectra and time evolution provides important information on ν physics and on SN evolution. Neutrino signal detectable from SN in our Galaxy or Magellanic Clouds 2 - 5 SN/century expected in our Galaxy. Plan for multidecennial observations 1000 tons liquid scintillator + layers of streamer tubes 300 ν from a SN in the center of Galaxy (8.5 kpc)

SN1987A

Early warning of neutrino burst important for astronomical observations with different messengers (photons, gravitational waves) SNEWS = Supernova Early Warning System LVD, SNO, SuperK in future: Kamland, BOREXINO

Large Volume Detector • 3 identical towers in the detector • 35 active modules in a tower

• 8 counters in one module

SNO (800) MiniBooNE (190)

Amanda IceCube

LVD (400) Borexino (80)

Super-Kamiokande (104) Kamland (330)

Tra parentesi il numero di eventi da una SN al centro della Galassia

BOREXINO 300 tons liquid scintillator in a nylon bag 2200 photomultipliers 2500 tons ultrapure water Energy threshold 0.25 MeV Real time neutrino (all flavours) detector Measure mono-energetic (0.86 MeV) 7Be neutrino flux through the detection of ν-e. 40 ev/d if SSM 18 m diam., 16.9 m height

Collab.: Italy, France, USA, Germany, Hungary, Russia, Belgium Poland, Canada

Sphere 13.7 m diam. supports the PMs & optical concentrators Space inside the sphere contains purified PC Purified water outside the sphere

Solar, atmospheric, reactor neutrino experiments

Emerging picture Tasks and Open Questions Normal 3

µ

Inverted τ

2 1

e

µ τ Sun µ τ e

Atmosphere Atmosphere 2 1

e

µ τ Sun µ τ e

3

µ

τ

• Precision for θ12 and θ23 • How large is θ13 ? • CP-violating phase ? • Mass ordering ? (normal vs inverted) • Absolute masses ? (hierarchical vs degenerate) • Dirac or Majorana ? • Anything beyond ?

Gran Sasso 2nd generation neutrino experiments Mass scale / Dirac or Maiorana? (CUORE, GERDA) Oscillation parameters (neutrino tau appearence, unitarity of the mixing matrix , matter effect) (OPERA, ICARUS, Borexino) How small θ13 ? ==> Improve limits (only if θ13 ≠ 0 and δ ≠ 0 CP leptonic violation possible) (OPERA)

Neutrinoless ββ Decay 0ν mode, enabled by Majorana mass

Standard 2ν mode

Some nuclei decay only by the ββ mode, e.g. 76As

O+

76Ge

2– 76Se

Half life ~ 1021 yr Measured quantity Best limit from 76Ge

2+ O+

Neutrino masses and 0ν2β decay Heidelberg Moscow experiment

0.1< mν (0.4) 10-24 y at 90% confidence level, corresponding to a range of effective neutrino mass < 0.09 - 0.20 eV within 3 years. Approved in 2005

ββ decay neutrinoless experiments β decay n --> p + e- + ν 2β0ν is a very rare decay: T(half life) ≥ 10-25 years)

Upper limit on ν=ν the mass of νe Majorana neutrino 0,39 eV Heidelberg-Moscow 11 kg of enriched 76Ge detect. The most sensitive experiment in the world 76Ge -->76Se + 2eGENIUS-TF Test facility for GENIUS 40 kg HM Ge Approved: GERDA Sensitive mass: 1 ton enriched Ge crystals in Liquid N2

MIBETA (Milan) 20 detectors of natural TeO2 crystals 130Te mass = 2.3 kg CUORICINO Sensitive 130Te mass = 40 kg Status: running CUORE proposal approved in 2004 130Te mass = 400 kg

Cuoricino The CUORICINO set-up, 11 planes of 4 cristals 5x5x5 cm3 and 2 planes having 9 cristals 3x3x6 cm3 of

TeO2 . The total mass is 40 kilograms, one order of magnitude bigger than other cryogenic detector The experiment is in data taking at Gran Sasso With Cuore neutrino mass sensitivity < 10-2 eV (dependent from the model) Now m < 0.4-2 eV

Cern Neutrinos to Gran Sasso (CNGS)

1979

Nobody has observed unambiguously the appearance of new flavours. You can’t do it at the solar scale (E too small to produce muons) At the atmospheric scale oscillations are very likely P(νµ → ντ) ≈ cos4 ϑ13 sin2 2ϑ23 sin2 [1.27 Δm223L(km)/E(GeV)] Hence, you must be able to identify unambiguously τ leptons CNGS has been designed for it

Over the next five years the present generation of oscillation experiments at accelerators with long-baseline beams are expected to confirm the νµ ντ interpretation of the atmospheric ν deficit and to measure sin2 223 and |∆m2 23| within 10 ÷ 15 % of accuracy if |∆m2 23| > 10-3 eV2. Neutrino facility

P momentum (GeV/c)

L (km)

E (GeV )

p.o.t./year (1019)

KEK PS

12

250

1.5

2

FNAL NUMI

120

735

3

36

CERN CNGS

400

732

17.4

4.5

K2K and MINOS are looking for neutrino disappearance, by measuring the νµ survival probability as a function of the neutrino energy while OPERA will search for evidence of ντ interactions in a νµ beam.

“today”

CNGS schedule

(schematic, simplified version)

18 August 2006

The 2 ways of detecting τ appearance @GRAN SASSO νµ …..

oscillation

ν τ → τ- +

CC interaction

OPERA: Observation of the decay topology of τ in photographic emulsion (~ µm granularity)

ICARUS: detailed TPC image in liquid argon and kinematic criteria (~ mm granularity)

X

µ- ντ νµ h- ντ nπο e- ντ νe π+ π- π- ντ nπο

ΒR 18 % 50 % 18 % 14%

Decay “kink”

ντ

τ-

ν

OPERA: an hybrid detector ν interaction

Electronic detector → finds the brick of ν interaction → µ ID, charge and p

Spectrometer (drift tubes-RPCs)

Emulsions+lead + target tracker (scintillator strips)

Basic “cell”

Emulsion analysis: Vertex Decay kink e/gamma ID Multiple scattering, kinematics

Pb Emulsion

1 mm

8 cm

CNGS beam performances

10.5 µs

50 ms

10.5 µs

LVD monitor of the CNGS beam Neutrinos from CNGS are observed through:  the detection of muons produced in neutrino CC interactions with the surrounding rock or in the detector  the detection of the hadron jets produced in neutrino NC/CC interactions in the detector

Gran Sasso rock νµ CNGS beam

µ

*

LVD

LVD monitor of the CNGS beam The neutrino candidate are defined as at least a signal from a counter of the detector with an energy deposit greater than 100 MeV. We can discriminate CNGS event from cosmic muons requiring:  horizontal direction of the reconstructed muon  time coincidence of the event with the CNGS time spill (cosmic muon background is then about 0.2 events/day)

From the Montecarlo simulation we expect 6.67 10-16 events/proton on target (p.o.t.) 1 year of data (200 days) -> 4.5 1019 p.o.t. -> 150 events/day

The first CNGS event: OνE

Event Display: µ from rock

Event Display: internal ν NC/CC?

22 8, 04:17

21 8, 07:30

20 8, 09:12

18 8, 11:30

LVD rate

Agreement between the observed events and the expected from the beam intensity!

Time event distribution The LVD CNGS events time distribution with respect to the time spill agrees with the duration of the spill!

The analisys of data taking with the LVD detector shows that:

the CNGS beam is working very well as it was expected

we continue to collect data and update the results we want to make a deeper analisys of the data to

extract more informations (external/internal, CC/NC)

OPERA Beam event

CC event originated from material in front of the detector (BOREXINO, rocks)

CC event in the first magnet µ-track

(forgive about the red-line fit)

Angular distribution of all events Clean selected events

Polar angle

Cosmic muons

Zoom on Beam events 3.5° from below

Azimuthal angle

OPERA conclusions • The CNGS beam is operating smoothly with very good quality • The tracking detectors of OPERA are taking data with practically no dead time • More than 100 beam correlated events have been observed with a clean time distribution • The recorded events show the expected tracking performances • OPERA is now ready for the next step: observing neutrino interactions in the Emulsion Cloud Chamber bricks

Next step : end of october run !!!

Next step: from electronic detectors to emulsion analysis Electronic detectors: Spectrometer Target Trackers Pb/Em. starget uperm odu

le

Emulsion analysis: Vertex, decay kink e/γ ID, multiple scattering, kinematics Pb/Em. brick

Link to mu ID, Candidate event

8m

Basic “cell”

Extract selected brick

Brick finding

8 cm

Pb Emulsion

1 mm

muon ID, charge and p

Binning ~ cm

10-4

Binning ~ μm

Brick production

BAM piling/pressing section

CS box Emulsion films Brick

Lead boxes

BAM wrapping section

Brick insertion, extraction, processing, Brick Manipulating System

Vacuum sucker vehicle

Emulsion developping lab

Detectors High energy beams only: Nufact or high

Hybrid emulsion (4 KT) • Experience from OPERA • Silver channel Interesting to solve

Neutrino Energy

degeneracies

CP asymmetry has opposite sign

γ β-beam

Tracking Calorimeters (100 KT) • Fully active with liquid scintillator: ~NOvA • Or sampling iron calorimeter: ~MINOS • Muon charge is crucial: B field !!! • Golden channel

• Golden and bronze also

Liquid Argon TPC (100 KT) Both

• 3D active detector: Imaging, calorimetry, Cerenkov • Challenging: ongoing R&D strategy Low energy beam only: • γ