The smallest pieces of
our universe
Sourabh Dube
25th September, 2016
Science =
Regular person asks “WHY?”
Answer: “blah blah blah”
RP: “oh great!”
2
Science =
Regular person asks “WHY?”
Answer: “blah blah blah”
RP: “oh great!”
Science lover : “WHY?”
Answer: “blah blah blah”
SL: “oh great! And HOW?”
3
What are the smallest pieces?
Take a piece of chalk.
Break it in pieces.
Take smallest piece.
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What are the smallest pieces?
Take a piece of chalk.
Gypsum.
Break it in pieces.
Take smallest piece.
Image by Smokefoot - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=45901685
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Molecules make up everything (?)
Water
DNA
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What are the smallest pieces?
Take a piece of chalk.
Gypsum.
Calcium
Sulphur
Oxygen
Hydrogen
Break it in pieces.
Take smallest piece.
Image by Smokefoot - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=45901685
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Molecules broken into atoms
Water
DNA
C
H
O
N
P
Oxygen
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Indistinguishability of atoms
Each atom of oxygen is exactly identical to
every other atom of oxygen.
Thus one water molecule is exactly the
same as any other water molecule.
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Too small to see...
But what if object is smaller
than wavelength of light?
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Too small to see...
Objects larger than wavelength
can be seen
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Too small to see...
Objects smaller than
wavelength need to be “seen”
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Too small to see...
13
Too small to see...
What if the wall
is invisible?
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Too small to see...
15
Too small to see...
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Rutherford's gold foil experiment
α-Particles shot
at gold foil
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Rutherford's gold foil experiment
Some -Particles
have large deflection
Most -Particles go
through with small
deflection
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Structure of atoms
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Structure of atoms
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Structure of atoms
“Orbiting
electrons”
Nucleus
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Structure of atoms
“Orbiting
electrons”
Nucleus
Atoms are mostly empty. If a nucleus were as big as a
person, then closest electron is roughly 100 kms away.
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Next step?
Nucleus
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Need for 'high' energy
A nucleus is very small.
To be able to 'look' inside it, we need a small object of
high energy.
Let me explain with an example.
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Inside a dark cave
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Inside a dark cave
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Inside a dark cave
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Inside a dark cave
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Size and Energy
Size we can look at, is inversely proportional to momentum
If
Length
Then
Energy
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So what's in a nucleus?
Protons
Neutrons
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So what's in a nucleus?
Protons
Neutrons
Deep Inelastic Scattering experiments with electrons
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So what's in a proton/neutron?
Protons
Neutrons
QUARKS
Up quark
Down quark
Proton = uud
Neutron = udd
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The smallest pieces of our
universe
Electron
Up quark
Down quark
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The smallest pieces of our
universe
Electron
Ahem!
Up quark
Down quark
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The smallest pieces of our
universe
Electron
Up quark
Neutrino
Down quark
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Periodic Table of Elements
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Standard Model of Particle Physics
Periodic Table of Particles
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SM explained...
Minimum players
needed to play the
game
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SM explained...
Minimum players
needed to play the
game (Matter)
Languages spoken
by the players
(interactions between
matter)
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SM explained...
More players (Matter)
Languages spoken
by the players
(interactions between
matter)
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Standard Model of Particle Physics
Particles
Particles speak
speak these
these
'languages'
'languages'
Electromagnetic
Electromagnetic
interaction
interaction
● Strong interaction
● Strong interaction
●
●
Weak
Weak interaction
interaction
● 'Higgs' interaction
● 'Higgs' interaction
●
●
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Standard Model of Particle Physics
Keep
Keepatoms
atomstogether,
together,
basis
basisofofchemistry,
chemistry,
biology
biology
Particles
Particles speak
speak these
these
'languages'
'languages'
Electromagnetic
Electromagnetic
interaction
interaction
● Strong interaction
● Strong interaction
●
●
Weak
Weak interaction
interaction
● 'Higgs' interaction
● 'Higgs' interaction
●
●
42
Standard Model of Particle Physics
Keep
Keepnucleus
nucleus
together
together(protons,
(protons,
neutrons)
neutrons)
Particles
Particles speak
speak these
these
'languages'
'languages'
Electromagnetic
Electromagnetic
interaction
interaction
● Strong interaction
● Strong interaction
●
●
Weak
Weak interaction
interaction
● 'Higgs' interaction
● 'Higgs' interaction
●
●
43
Standard Model of Particle Physics
Particles
Particles speak
speak these
these
'languages'
'languages'
Make
Makeradioactivity,
radioactivity,
make
makethe
theSun
Sunglow!
glow!
Electromagnetic
Electromagnetic
interaction
interaction
● Strong interaction
● Strong interaction
●
●
Weak
Weak interaction
interaction
● 'Higgs' interaction
● 'Higgs' interaction
●
●
44
Standard Model of Particle Physics
Particles
Particles speak
speak these
these
'languages'
'languages'
Electromagnetic
Electromagnetic
interaction
interaction
● Strong interaction
● Strong interaction
●
●
Give
Givemass
masstoto
fundamental
fundamentalparticles!
particles!
Weak
Weak interaction
interaction
● 'Higgs' interaction
● 'Higgs' interaction
●
●
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LHC: Large hadron collider
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CMS detector
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CMS is a giant camera
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Reconstruction
Object
Detector
Data collected
Data analyzed
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Reconstruction
Cat!
Object
Detector
Data collected
Data analyzed
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Nature of research
The Edge of
Human Knowledge
A non-researcher's view...
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Nature of research
The Edges of
Human Knowledge
A researcher's view...
52
Why I like science?
Objective Proof
(does not depend on specific person)
Cause and effect (reproducible)
Why? And How?
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IISER Pune CMS group
...along with summer students
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