1.3- Unification of forces

What is the idea behind unification of forces?

Forces may only appear different because their range differs; at high energies their strengths become equal.

Why is the weak force short‑range?

Because the particles that mediate it- W and Z bosons are heavy, giving the weak force a range of ~2×10⁻¹⁸ m.

What is the equation for the wave that describes particle motion?

What is the de Broglie wavelength of a relativistic particle?

When does a wave “see” an object of size a?

What is the condition for a large probility of interaction?

What is the range of a force mediated by a particle of rest‑mass energy E₀?

When is the weak interaction very weak?

When do weak and electromagnetic forces become equally strong?

What makes up the Standard model?

What did the electroweak theory predict?

What mechanism gives W^+- and Z⁰ and all other particles their mass?

Higgs mechanism / Higgs field.

What does the Higgs mechanism imply?

A neutral, spin‑0 Higgs boson.

Why is the Standard Model incomplete?

It does not include dark matter or gravity.

What happens at even higher energies?

Strong interaction may unify → GUTs (Grand Unified Theories).

What new particle appears in GUTs?

X boson.

What major consequence do GUTs allow?

Proton decay.

Which conservation laws would break in proton decay?

• Baryon number

• Lepton number

Has proton decay been observed?

No — not yet.