1. The Mysteries of Particle Physics and how we are trying to solve them
Owen Long, UC Riverside
July 27, 2017
QuarkNet Workshop

2. Our "Standard Model" of Particles

3. Our "Standard Model" of Particles
We are made of these…
… and held together by these

4. Our "Standard Model" of Particles
We are made of these…
… and held together by these
This allows some unstable nuclei to decay (radioactivity).

5. Our "Standard Model" of Particles
We are made of these…
… and held together by these
This allows some unstable nuclei to decay (radioactivity).
These are like ghosts. They weigh almost nothing and hardly interact at all.

6. Our "Standard Model" of Particles
These are extra copies of the matter particles. We don't know why they are there.
We are made of these…
… and held together by these
This allows some unstable nuclei to decay (radioactivity).
These are like ghosts. They weigh almost nothing and hardly interact at all.

7. Our "Standard Model" of Particles
These are extra copies of the matter particles. We don't know why they are there.
The Higgs field gives particles what we call mass.
We are made of these…
… and held together by these
This allows some unstable nuclei to decay (radioactivity).
These are like ghosts. They weigh almost nothing and hardly interact at all.

8. The "Standard Model" of particles
No Standard Model particles left to look for.
Are we done? No!

9. The "Standard Model" of particles
No Standard Model particles left to look for.
Are we done? No!
Some Mysteries of Particle Physics
What is Dark Matter?
Where did the antimatter go (or why are we here)?
Is there a Grand Unified Theory?
Are there more than three space dimensions?
Why is the Higgs boson so light?

10. Extra Dimensions?
Might explain why gravity is so weak.

11. Extra Dimensions?
Might explain why gravity is so weak.

12. Why is the Higgs boson light?
We found the Higgs Boson and measured it's mass: 125 GeV.
If the Standard Model is all there is, we know how to calculate radiative corrections to its mass.

13. Why is the Higgs boson light?
We found the Higgs Boson and measured it's mass: 125 GeV.
If the Standard Model is all there is, we know how to calculate radiative corrections to its mass.
Problem: size of corrections are much larger (~1018) than the mass we found

14. Why is the Higgs boson light?
We found the Higgs Boson and measured it's mass: 125 GeV.
If the Standard Model is all there is, we know how to calculate radiative corrections to its mass.
Problem: size of corrections are much larger (~1018) than the mass we found
Huge uncorrected mass
Small observed mass
Equally huge correction

15. Why is the Higgs boson light?
We found the Higgs Boson and measured it's mass: 125 GeV.
If the Standard Model is all there is, we know how to calculate radiative corrections to its mass.
Problem: size of corrections are much larger (~1018) than the mass we found
Several ideas on what New Physics would give a more natural explanation. One is Supersymmetry.
Huge uncorrected mass
Small observed mass
Equally huge correction

16. Supersymmetry : 3 birds with 1 stone
"The systematic cancellation of [dangerously large radiative corrections to the Higgs mass] can only be brought about by the type of conspiracy that is better known to physicists as a symmetry." Steve Martin (the physicist, not comedian)
Every Standard Model particle gets a supersymmetric partner.

17. Supersymmetry : 3 birds with 1 stone
"The systematic cancellation of [dangerously large radiative corrections to the Higgs mass] can only be brought about by the type of conspiracy that is better known to physicists as a symmetry." Steve Martin (the physicist, not comedian)
Every Standard Model particle gets a supersymmetric partner.
Potentially solves 3 mysteries:
Cancellation of huge Higgs mass corrections.
Could be Dark Matter
Consistent with grand unification of the strong, electromagnetic, and weak forces (unlike the Standard Model).

18. Searching for Supersymmetry
The lightest SUSY particle is stable and weakly interacting. It could be what Dark Matter is made of.
Carries away momentum without leaving a trace in the detector.

19. Summary Our job in particle physics is far from complete.
The Large Hadron Collider is at the frontier of fundamental physics.
The CMS experiment is our microscope, probing the shortest distance scales ever examined in a laboratory.