THE INFN VISION FOR NEUTRINO PHYSICS
Fernando Ferroni INFN & Universita’ Sapienza Roma
STATUS OF THEORETICAL UNDERSTANDING AND OF EXPERIMENTAL POWER FOR LHC PHYSICS AND BEYOND
Erice 52st Course: June 23-July 3 2014
A SPECIAL PARTICLE FOR US
"The name neutrino was coined by Enrico Fermi as a word play on neutrone, the Italian name of the neutron."
A Majorana fermion, also referred to as a Majorana particle, is a fermion that is its own antiparticle. They were hypothesised by Ettore Majorana in 1937. !Neutrino is the only particle known to us that could be a Majorana fermion.
the prediction that neutrinos associated with electrons are different from those associated with muons
the intuition of how to detect anti-neutrinos generated in nuclear reactors
A SPECIAL PARTICLE FOR US
the idea that neutrinos may convert into other type of neutrinos
Bruno Pontecorvo
THE ONLY PARTICLE WE HAVE SEEN THAT MIGHT BELONG TO
!
!
‘NEW PHYSICS’
AN HISTORY OF SURPRISES
The very existence
ITS FIRST OBSERVATION (A BIT EARLIER THAN PREDICTED BY PAULI
Cowan & Reines
Pauli bet a case of champagne that nobody would ever detect one. Indeed this was the case until 1956, when Clyde Cowan and Fred Reines detected antineutrinos emitted from a nuclear reactor at Savannah River in South Carolina, USA. When their result was announced, Pauli kept his promise.
MORE THAN ONE !
AN INTRIGUING PUZZLE
does the Sun really shine ?
and how is it possible ?
Davies
NEUTRINO MASS: SURPRISE !
Within the standard model, the right-handed neutrino does not exist, so even with a Yukawa coupling neutrinos remain massless
The reason neutrino oscillation is relevant to the question of neutrino mass is that massless neutrinos cannot oscillate. Put another way, observation of oscillation implies that the masses of the neutrinos involved cannot be equal to one another. Since they cannot be equal to one another, they cannot both be zero. In fact it is quite likely that if any neutrinos have non-zero mass, all of them do.
Koshiba
Serendipity at work !
TRANSFOMATION UNDER YOUR EYES
OPERA at LNGS
Muon neutrinos leave
CERN and sometime
they are detected as tau
neutrinos at Gran Sasso
IS THAT OVER ? DEAL DONE ?
FAR FROM IT
AN ENDLESS RESEARCH FIELD
How much does a neutrino weigh ?
What is the mass ordering (hierarchy)
Is neutrino a Majorana or Dirac particle
Do more (sterile) neutrinos exist ?
Do neutrinos violate CP ?
Can we observe the CNB (a picture of a universe 1 second old)
INFN IS COMMITTED !
on neutrino absolute mass
on mass hierarchy
on Majorana vs. Dirac
on sterile neutrino search
on CP violation
NEUTRINO MASS DIRECT MEASUREMENT
Brute force ?
Nein, danke !
We’d rather prefer………….……………………
HOLMES
The Electron Capture Decay of 163Ho to Measure the Electron Neutrino Mass with sub-eV sensitivity
electron capture from shell >= M1A. De Rujula and M. Lusignoli, Phys. Lett. B 118 (1982) 429
AN EXCITING OPPORTUNITY
Nev=1014; FWHM=2eV
M2 M1
DREAMING FOR
AIMING ATTransition Edge Sensors (TES) with 163Ho implanted Au absorbers
6.5x1013 nuclei per detector → 300 dec/sec
ΔE≈1eV and τR≈1µs
1000 channel array
6.5x1016 163Ho nuclei → ≈18µg
3x1013 events in 3 years
DETECTORS
Transition Edge Sensors (TES) with
Bi/Au absorber
single pixel developmentarray fabrication (NIST, Boulder,
USA)
HOLMES DETECTOR ARRAY
HOLMES array: 256 sparse pixels (4x)
MASS HIERACHY
1-2 ordered by matter
3 is free
degeneracy belong to an other type of experiments
JUNO: THE REACTOR OPTION
Very tough challenge
Bring in expertise in purification
of liquid scintillator from Borexino
GREAT PHYSICS …GREAT CHALLENGE !
MAJORANA VS. DIRAC
NEUTRINOLESS DOUBLE BETA DECAY
Only if: !
Majorana Neutrinos Massive Neutrinos
If observed: !
Proof of the Majorana nature of Neutrino Indication of mass scale
EBtMK
Δ⋅⋅
∝ (i.a. • ε)
mᵦᵦ ∝ √ (1/τ)
S
JUST A PILE-UP OF NIGHTMARES
WE ARE PREPARING CUORE
WITH THIS GOAL
you soon hit a wall !
EXPLOIT THE TECHNOLOGY
THAT LOOKS LIKE….
1000 thousand crystals of TeO2. 130Te is the most natural candidate for DBD (34% i.a.)
BUT WILL STOP AT
irreducible if you do not tell alphas from gammas in spite of formidable energy resolution
THERE IS A POSSIBLE SOLUTION
Zn82Se or Zn100MoO4
ZnSe ZnMoO4
or Cherenkov from TeO
100 eV@Q-valueRequires ~20 eV resolution for >99.9% α rejection @ >90% signal efficiency
The CALDER projectDevelopment of light detectors based on the
Kinetic Inductance Detector (KIDs)
STERILE NEUTRINOS QUEST
Triggered by anomalies (none of which outstanding !) in several experiments (LNDS, Mini-Boone, reactors)
a final (!?) word is needed (the manual of good experimentalist !)
different possibilities: we have chosen neutrino sources (VSBL) and SBL
THE VSBL WAY
Tank!3300 m3 of water!
210 PMTs Cherenkov!
Principle:!“graded shielding”.!
!Pure and pure materials toward the center of the
detector!
Scintillator!270 t PC-PPO!
Nylon Vessels!internal: R=4.25 m!external: R=5.50 m!
PIT !~ 1 m3 available at"
8.25 cm from the center!
Stainless Steel Sphere!~1300 m3 of liquid!
support for 2214 PMTs!
Take a fully understood existing detector
A detector that has ‘written’ a good
part of the neutrino oscillation story
BOREXINO@LNGS
PORTABLE SUN (PROVIDED BY ERC)
pit
144Ce SOX-C
144Ce SOX-B
51Cr SOX-A
• Mission: test the existence of low L/E �νe and/or νe anomalies by placing �well known artificial sources close to �or inside Borexino"
• SOX-A now SOX-Cr"• 51Cr source in pit beneath detector !• 8.25 m from center [2017?]"
• SOX-B now SOX-Ce"• 144Ce-144Pr source in pit.!• Option: PPO everywhere to enhance sensitivity !• 8.25 m from center [2015]"
• SOX-C"• 144Ce-144Pr source in the center!• Only after the end of solar program"• More effort and more time�
[>2018]�"
THE HOMEMADE SUN RAYS
ANALYSIS TECHNIQUETotal counts: standard “disappearance” experiment!
Total number of events depends on θ14 and (weakly) from Δm214 Sensitivity depends on:!
Statistics (source activity)!Error on activity (in particular) and on efficiency!
The relatively short life-time of 51Cr yield useful time-events correlation!The background is constant while the signal is not!
!Spatial waves [C.. Grieb et al., Phys. Rev. D75: 093006 (2007)]!
With expected Δm2 e and ~ 1 MeV energy, the wavelength is smaller than !detector size (~11 m max) and bigger than resolution (~ 15 cm)!
The distribution of events as a function of distance to source shows waves Direct measurement of Δm142 and θ14 Very powerful and independent. Does not depend on knowledge of source activity. !
!The two techniques can be combined in a single counts-waves fit!
A POSSIBLE RESULT
Reactor anomaly central value
1 σ 3 σ
Full Geant4 simulation - example Borexino Background
Example for SOX-Cr
LIKELY AN EXCLUSION
BUT IF YOU WANT A FINAL WORD YOU NEED AN ACCELERATOR
AND A SUPERB QUALITY DETECTOR
ICARUS Electronic chamber
Medium Liquid ArgonSensitive mass Many ktonsDensity 1.4 g/cm3Radiation length 14.0 cmCollision length 54.8 cmdE/dx 2.1 MeV/cm
Gargamelle Bubble chamber
Medium Heavy freonSensitive mass 3.0 tonDensity 1.5 g/cm3Radiation length 11.0 cmCollision length 49.5 cmdE/dx 2.3 MeV/cm
for those of you
that are old enough
to remember…..
a couple of years
operation in CNGS
A SOUND PROPOSAL AT FNAL
ICARUS T600
SBN@BNB
END OF A STORY OR PERHAPS START OF AN ADVENTURE
νμ � νe Appearance#
but…beware…very difficult experimental conditions. TBV.
CP VIOLATION IN NEUTRINO SECTOR
uhmmmm……..
U.S.-hosted Long Baseline Neutrino Facility (LBNF) that receives the world’s highest intensity neutrino beam from an improved accelerator complex (PIP-II) at Fermilab.
Reformulate the long-baseline neutrino program as an internationally designed, coordinated, and funded program with Fermilab as host.
Redirect specific activities and efforts at Fermilab to the PIP-II program of improvements to the accelerator complex, which will provide proton beams with power greater than one megawatt by the time of first operation of the new long-baseline neutrino facility.
LAr
ICARUS@CNGS
A demonstration
of the power of
the technology
LBNF
INFN, thanks to ICARUS group, masters the LAr technology.
We are willing to partecipate in trying to build such a collaboration for a future experiment.
The previously mentioned project (SBL at FNAL) should help in getting people together around a common program
CONCLUSIONS
Neutrino physics is an absolute priority for INFN
We center our program at Gran Sasso lab but we participate in experiments worldwide
Neutrino is the only known particle that we have still to understand
It is the most promising gate to the New Physics land
It is a beautiful ground for young talents to put their skill at work
