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THE NEUTRINO PARTICLE: HOW TO LEARN A GREAT DEAL BY OBSERVING NOTHING A DRAMA in Four Acts and a Dozen Scenes Haim Harari. Act I BEFORE PRE-HISTORY. SCENE 1. Looking Back in Time. The edge of the universe. =. The beginning of the universe. Distant observations. - PowerPoint PPT Presentation
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THE NEUTRINO PARTICLE:
HOW TO LEARN A GREAT DEAL
BY OBSERVING NOTHING
A DRAMA
in Four Acts
and a Dozen Scenes
Haim Harari
THE NEUTRINO PARTICLE:
HOW TO LEARN A GREAT DEAL
BY OBSERVING NOTHING
A DRAMA
in Four Acts
and a Dozen Scenes
Haim Harari
Act I
BEFOREPRE-HISTORY
Act I
BEFOREPRE-HISTORY
Looking Back in Time Looking Back in Time
The detector must observe the desired radiation, not the undesired one.
SCENE
1
The edge of the universe
Studying the beginning of the universe
The beginning of the universe
Distant observations
"Conventional" astronomy: Visible light and other kinds of radiation"Obstacles": Clouds, the atmosphereAvoiding "background": A Dark night, no background radiation
=
DarknessDarkness
The universe is "flat" and its total mass is known70% - Dark energy25% - Dark matter, mostly unknown 4% - Free Hydrogen and Helium0.5% - Stars
SCENE
2
The beginning of the universe Complete darknessOuter Space Complete darknessMost matter in every galaxy Invisible and darkMost matter in the universe Invisible and darkMost energy in the universe Invisible and dark
Understanding the universe and its creation requires an intensive study of the invisible dark matter and energy
Light and other radiation, come to us from the surface of a star
What happens inside the sun? What happens inside a star, when it is born? When it develops? When it explodes?
The Inside storyThe Inside story
The temperature on the surface of the sun: thousands of degrees.The temperature inside the sun: millions of degrees.Understanding the secrets of the suns requires looking inside the sunUnderstanding the secrets of a star requires an "inside photograph"
SCENE
3
Act II
A “TERRIBLE” TALE
ABOUT
AN INVISIBLE PARTICLE
Act II
A “TERRIBLE” TALE
ABOUT
AN INVISIBLE PARTICLE
A1 A2 + e-
e-
decay
Dear Radioactive Ladies and GentlemenDear Radioactive Ladies and GentlemenSCENE
1
N1 N2 + e-
e-e-
e-
e-
The electron energy:Always the same?
Dear Radioactive Ladies and GentlemenDear Radioactive Ladies and GentlemenSCENE
1
decay
Dear Radioactive Ladies and GentlemenDear Radioactive Ladies and GentlemenSCENE
1
The electron energy: Always the same?
Experiment: Not at all.Every time a different energySome energy is always missing
Someone is "stealing" energy
The Neutrino: Dark, invisible, penetrating, elusive, massless (?)
Neutrino
N1 N2 + e- +
e-e-
e-
e-
Dear Radioactive Ladies and GentlemenDear Radioactive Ladies and GentlemenSCENE
1
decay
n p + e- +
np
np
e-
e-
e-
e-
e-
decay
Dear Radioactive Ladies and GentlemenDear Radioactive Ladies and GentlemenSCENE
1
WE NEED A PROCESS, WHICH IS A MILLION TIMES "STRONGER“ !WE NEED A PROCESS, WHICH IS A MILLION TIMES "STRONGER“ !
What is the source of energy of the sun?Burning conventional fuel?
The mass is sufficient for thousands of years.But the sun exists billions of years.
SCENE
2 The Secret of the SunThe Secret of the Sun
A nuclear "fire" inside the sun
All nuclear processes in the sun emit neutrinosthe life story of every star is related to similar processes
Creating the heavy chemical elements
p ne,
Hans Bethe
We must: Look into the center of the sun Look into the center of the star
SCENE
2 The Secret of the SunThe Secret of the Sun
Nevertheless:
+n e- + p
When 10 neutrinos pass through Earth, only one hits something.
SCENE
3 Catching the thiefCatching the thief
Pauli: "I did a terrible thing.I postulated a particle,which cannot be discovered"
16
Reines-Cowan 1956 THE THIEF HAS BEEN CAUGHT!
SCENE
3 Catching the ThiefCatching the Thief
DetectorReactor
Act III
"WHO ORDERED THAT?"
Act III
"WHO ORDERED THAT?"
p, n, e-, 1935: The Elementary Particles
SCENE
1 And what would you like for dessert?And what would you like for dessert?
A comedy of errorsYukawa predicted 1935Anderson-Nedermayer discovered 1937The celebration started … and ended 1945Powel discovered the Yukawa particleAnderson-Nedermayer remained with a shocking discovery
p, n, e-, 1935: The elementary particles
SCENE
1 And what would you like for dessert?And what would you like for dessert?
– 200 times heavier than the
electron,but identical to it in all other properties
Meanwhile: Dozens of new particles All are made out of quarks
Ordinary matter
Heavy matter s -
u d e- e
e
The first neutrino beam in an acceleratorA proof that there are two distinct kindsof neutrinos
Schwarz Lederman Steinberge
SCENE
1 And what would you like for dessert?And what would you like for dessert?
And the neutrino? The electron comes with a neutrino
is also created with a neutrinoAre these neutrinos identical?
11/11/1974
An indirect observation of an additional quark cCompleting the "second generation" of building blocks
SCENE
2 The November RevolutionThe November Revolution
u d e e
c s
t b
First generation
Second generation
Third generation No more!
The standardmodel
t b
Within a year
Discovery of the third "brother" of the electronPredicting the third neutrinoPredicting the "third generation" of quarks
Does the neutrino have a mass? If so, it is tiny
Theory: There is a good reason for a tiny mass, no explanation for a zero mass.
e
No reason for an identity between the two classifications
Mixing and oscillations are expectedA three-way schizophrenia
SCENE
3 ReincarnationReincarnation
Example:
e Emitted from the sun.
On its way to us, converts into
Emitted from an accelerator.
On its way to detector converts into
Conclusion:Neutrino oscillations non-vanishing neutrino massesFirst experiments in accelerators and nuclear reactors –
negative results!
SCENE
3 ReincarnationReincarnation
Act IV
WE SEE NOTHING
Therefore
EVERYTHING IS CLEAR
Act IV
WE SEE NOTHING
Therefore
EVERYTHING IS CLEAR
What is happening inside the sun?Who can escape from the center of the sun and reach us on earth?Where can we "catch" a neutrino" Everywhere !Where is the minimal "background"? Deep undergroundHow do you catch neutrinos?
SCENE
1 Underground AstronomyUnderground Astronomy
Gae + Ge71
Gallex
30 tons
400 tons of cleaning fluid
Cle + A37
Homestake
SCENE
1 Underground AstronomyUnderground Astronomy
e
+ n e + pKamiokande
5000 tons water
SCENE
1 Underground AstronomyUnderground Astronomy
Super-luminary"Boom"
Koshiba et al: The ratio between the types of neutrinos in cosmic radiation is also different from the expected ratio.
SCENE
2 What did the fourth guest get for dessert?What did the fourth guest get for dessert?
Davis et al: Number of neutrinos arriving from the sun is only one third of the expected numberKirsten, Dostrovsky et al: About half of the expected numberKoshiba et al: About half of the expected number
Conclusion: Neutrino mixing and neutrino oscillations!!!The neutrinos have tiny masses!
eAnd the fourth
guest also received something he did
not order!
SCENE
2 What did the fourth guest get for dessert?What did the fourth guest get for dessert?
- 50 meV
- 8 meV
- Lighter
The challenge: Understanding the dark matter and the dark energy
The birth of a neutrino astronomy, performed underground
1. Understanding processes inside the sun2. Understanding star explosions (Supernova)3. Studying neutrino properties
Neutrinos are approximately 0.5% of the universe mass. In every cubic centimeter of the universe there are
400 photons and 110 neutrinos of each of the three kinds.
SCENE
3 A voyage into the darknessA voyage into the darkness
"Neutrino physics is largely the art of learning a great deal by
observing nothing"
The tiniest and most elusive particle plays a crucial role in creating the universe
We observe the inside of a star and study the darkness of the universe,
by going underground !
EpilogEpilog
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