1. What are elementary particles, and why should we care?
Dhiman Chakraborty
QuarkNet Masterclass, NIU, 14 March, 2012

2. QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

3. The fundamental questions
What is the world made of?
What holds it together?
How did it all start?
What does the future hold?
What/who else is out there?
“What is it that breathes fire into the equations and makes a universe for them to describe? Why does the universe go to all the bother of existing?”
– Stephen Hawking
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

4. Unsolved mysteries
Driven by new puzzles in the understanding of our physical world, particle physicists are finding paths to new wonders and startling discoveries. Experiments may even find hidden extra dimensions, mini black holes, and/or evidence of string theory.
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

5. Unsolved mysteries QuarkNet Masterclass NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

6. Unsolved mysteries QuarkNet Masterclass NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

7. Unsolved mysteries QuarkNet Masterclass NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

8. Unsolved mysteries QuarkNet Masterclass NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

9. The small QuarkNet Masterclass NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

10. The large QuarkNet Masterclass NIU, 14 March 2012
Graphics courtesy: NASA
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

11. Exploring the Universe with Hubble Ultra-Deep Field reveals galaxies forming and evolving
Photo courtesy: NASA
QuarkNet Masterclass
NIU, 14 March 2012

12. The extremes are connected
We want to explain the structure and phenomena at the largest scales (cosmology), in terms of the smallest (particle physics).
Particle physicists, in turn, are getting their cues from cosmological observations.
The two are inextricably coupled. Fortunately, they are also easier to model precisely than anything in between. Systems in biology, economics, geology etc. are far more complex.
Particle astrophysics is a rapidly growing field.
95% of what constitutes the Universe is yet unknown/ unobserved. Some of it must be explained by particle physics.
A revolution of unparalleled proportions is around the corner.
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

13. Composition of the Universe
Graphics courtesy: NASA
QuarkNet Masterclass
NIU, 14 March 2012

14. QuarkNet Masterclass
NIU, 14 March 2012

15. Ways to study structures
Cosmology: Look at the object object at all possible wavelengths
Particle physics: Shoot all possible probes at the object
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

16. To probe small distances, we need high energies: E = 2/ , where is the wavelength of probe
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

17. Matter and interactions
“Matter”: made of Fermions.
Spin-(2n+1)/2 particles that do not share a quantum state.
Consequently, their production, annihilation, or decay must be associated with either another fermion or an “anti- fermion”. This results in the conservation of number of matter particles.
“Interactions”: mediated by Bosons.
Spin-n particles that gladly share a quantum state.
Can be radiated, absorbed, or decayed singly. Thus, the number of bosons is not conserved.
Bosons can interact among themselves.
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

18. The four forces (carried by bosons)‏
Affects everything,
Infinite range,
No neutralization
Dominant at planetary-to-cosmic scales
No quantum description yet.
Affects only electrically charged bodies,
Infinite range,
Bound states are often neutral
Prominent at atomic-to-stellar scales
Affects all fermions,
Very short (sub- nuclear) range,
Not a binding force,
Only interaction to cause transmutation of matter.
Affects only “color”- ed objects (quarks & gluons),
Very short (nuclear) range,
Strong neutralization
Dominant at nuclear scales
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

19. The matter particles (fermions)‏
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

20. Beyond SM: Grand Unification
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

21. Unification of forces Diagram courtesy: H. Murayama
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

22. Unification theories QuarkNet Masterclass NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

23. Open questions What makes fundamental particles massive?
Why do fermions come in multiple “flavor”s? Could it be related to their mass?
What can we learn from the neutrinos?
Are there undiscovered principles of nature? New symmetries? New physical laws? “Extra” dimensions? Do all forces unify at high energies?
What happened to all the antimatter?
How can we explain the “Dark Energy”?
What constitutes the “Dark Matter”?
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

24. The many connections QuarkNet Masterclass NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

25. A timeline of HEP Colliders
The LHC is almost certain to make revolutionary discoveries within first 2-3 years of full-scale operation.
The ILC/NLC will help us make high- precision measure-ments pin down the details of any new TeV-scale physics.
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

26. Fermilab QuarkNet Masterclass NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

27. Collider Detectors DØ CDF QuarkNet Masterclass NIU, 14 March 2012
Replace CDF with CMS/ATLAS
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

28. A top-antitop event QuarkNet Masterclass NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

29. A top-antitop event QuarkNet Masterclass NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

30. The Large Hadron Collider (LHC) at CERN
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

31. LHC parameters Circumference Collision Energy Injection energy
Crossing angle
Particles per bunch
Number of bunches
Dipole field
Number of dipole magnets
Number of quadrupole magnets
Number of corrector magnets
Luminosity
26.7 km (16.56 mi)‏
7+7 TeV
0.45 TeV
300 μrad
1011
2808
8.33 Tesla
1232
about 600
about 7000
1034 cm-2s-1
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

32. The ATLAS detector at LHC
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

33. Outlook
A large number of particle physics, astrophysics, and cosmology projects – both theoretical and experimental – are underway. They complement each other toward a common goal – to solve the most fundamental mysteries of nature.
It is a truly INTERNATIONAL effort.
We are living through a revolution in our understanding of the Universe on both the smallest and the largest scales.
The next decade or two will usher us into a new era of observation and comprehension.
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty

34. Feel free to contact the speaker
THANK YOU!
Feel free to contact the speaker
for more information
QuarkNet Masterclass
NIU, 14 March 2012
Elementary particles & cosmology
- Dhiman Chakraborty