particle physics: status and perspectives part 9: energy frontier and open questions manfred jeitler
Post on 17-Jan-2016
212 Views
Preview:
TRANSCRIPT
Particle Physics: Status and PerspectivesPart 9: Energy Frontier and Open Questions
Manfred Jeitler
Supersymmetry
2
Supersymmetry
3
Every fundamental matter particle should have a massive "shadow" force carrier particle, and every force carrier should have a massive "shadow" matter particle.
This relationship between matter particles and force carriers is called supersymmetry.
For example, for every type of quark there may be a type of particle called a "squark."
Supersymmetry (“SUSY”)
4
Cancellation of quadratic terms (divergences)
5
to avoid quadratic divergences in Higgs mass, “fine-tuning” is needed
Running Coupling constants: Grand Unification
6
U(1) (hypercharge) SU(2) (left) SU(3) (color) coupling constants get almost equal at high energies but not quite, in Standard Model (left) perfect match in Supersymmetry (right)
Parameters of the Standard Model
7
α1 = (5/3)g′2 /(4π) = 5α/(3 cos2 θW )
α2 = g2/(4π) = α/ sin2 θW
α3 = gs2/(4π)
α1(MZ) = 0.017
α2(MZ) = 0.034
α3(MZ) = 0.118 ± 0.003.
8
massive astrophysical cosmic halo objects?weakly interacting massive particles?
questions of cosmology to particle physics:Why is there more matter than anti-matter in the universe?What is the universe made of? What is dark matter?What is dark energy?
answers to these questions concerning the largest scales might come from the physics of the smallest scales - elementary particle physics
dark matter: MACHOS vs WIMPS
How to see SUSY decays
10
SUSY particles may show very clear signatures due to cascade decays
11LIGO (Laser Interferometer Gravitational Wave Observatory, USA)
measurement of gravitational waves
12
important questions of today’s particle physics(ongoing experiments)
• Why are particle masses so different?
• Is there an overall (hidden) symmetry such as supersymmetry (SUSY) “mirror world” of all known particles?.
• What is the nature of “dark matter” and “dark energy” in the universe?
• Why is there more matter than anti-matter?
• Why have neutrinos such small mass?
• Is there a Grand Unification which combines all interactions, including gravitation?
• Are there extra dimensions, D > 4 ? ( string theory, …)
13
top related