Particle physics

Electroweak interactions and QED

Observe gauge fields and electroweak-style interactions in three dimensions. Relate the visible field structure to the gauge group $SU(2)_L \times U(1)_Y$ and the idea of mediator bosons carrying forces.

Research

Equipment

3D view of the interacting gauge field
Sliders for strength and energy scale
Pause and reset-view buttons

Procedure

Survey the gauge field
Rotate the 3D view to survey the field network and interaction streamlines. Recall that in QED the photon is the gauge boson of $U(1)$ , while the weak force needs the three bosons of $SU(2)_L$ . Read the current field-strength value in the readout.
Vary the interaction strength
Sweep the "Strength" slider and note how the field structure responds — analogous to varying the coupling $g$ in $D_\mu = \partial_\mu + igA_\mu$ . Then change "Energy scale": in the electroweak model, symmetry breaking at the $\sim$ 246 GeV scale gives W and Z their masses while the photon stays massless.
Relate to coupling constants
Press "Pause" at two different strengths and compare: stronger coupling gives a more tightly wound field structure. Relate: the electric charge $e = g\sin\theta_W$ connects the $SU(2)_L$ and $U(1)_Y$ couplings through the Weinberg angle $\theta_W$ . Reset the view and check the field's symmetry in different directions.

Simulation

Experiment history

Gauge interactions began with Weyl's theory (1918–1929), which recognized local gauge invariance as the origin of electromagnetism. In 1954 Yang and Mills extended the idea to the non-abelian group

SU(2)

— the ancestor of all modern gauge theories. Glashow (1961) proposed

SU(2)_L \times U(1)_Y

for the electroweak force; Weinberg (1967) and Salam (1968) added the Higgs mechanism to give W and Z their masses. Gerard 't Hooft and Martinus Veltman proved the theory renormalizable (1971), enabling quantitative predictions. The W and Z bosons were discovered at CERN in 1983 by UA1/UA2 (Rubbia, van der Meer) at the predicted masses ~80–91 GeV. During the 1970s QCD (

SU(3)

) completed the Standard Model: three forces — electromagnetic, weak, strong — all arise from local gauge symmetry.

Related physicists

Paul Dirac Richard Feynman Chen Ning Yang Steven Weinberg Sheldon Lee Glashow Mohammad Abdus Salam Peter Ware Higgs

Equipment

Procedure

Simulation

Experiment history

Related physicists

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