How a Particle Collider Works — Live in Your Browser
A collider does three things: it accelerates two beams of particles to enormous energy, smashes them head-on, and reads the debris that sprays out. Our particle collider simulator lets you drive all three in the browser. This is the plain-English tour of what you're watching — and, just as importantly, an honest note on which parts are real physics and which are a helpful cartoon.
1. Turning energy into matter
An electron and a positron — its antimatter twin — are sent around a ring in opposite directions and brought together at a single spot, the interaction point. When they meet head-on they can annihilate, and their combined energy reappears as brand-new particles. That's E = mc² run backwards: energy becoming mass.
There's a catch, and it's a real rule you can feel in the simulator. To create a particle and its antiparticle, the collision energy — written √s, the total centre-of-mass energy — has to clear twice that particle's mass. A pair of muons (heavy cousins of the electron, about 106 MeV each) needs √s above roughly 0.21 GeV; heavier things need more. Slide the energy up and new options switch on as you cross each threshold.
2. Reading the debris: why the tracks curve
The detector sits inside a strong magnetic field, and a magnetic field bends the path of
any charged particle. The force, q·v×B, always pushes
sideways to the motion, so a charged track curves into an arc. How tightly it curves is
set by one clean relation:
r = p / (|q|·B)
The bigger a particle's momentum p, the gentler the bend — so
a nearly straight track is a fast, high-energy particle, and a tight curl is a slow one.
And because the force flips direction with the sign of the charge, a positive particle and
its negative partner bend opposite ways. That single picture is how a real
experiment measures both momentum and charge at a glance. It's the exact same force you can
watch bend a lone charge into a circle in our
charged-particle lab.
One more tell: neutral particles have no charge, so the field can't touch them. Photons fly dead straight and leave no track at all — they show up only as a splash of energy in the calorimeter, the detector's outer ring. Straight-and-only-in-the-calorimeter versus curved-in-the-tracker is how you separate the neutral from the charged.
3. The Z⁰ at 91 GeV: a resonance
Push the energy toward 91 GeV and something dramatic happens: the collision rate spikes. At that exact energy the electron and positron can make a real Z⁰ boson — the neutral carrier of the weak force, with a mass of about 91.19 GeV. Hitting it is like pushing a swing at just the right rhythm; physicists call it a resonance, and its shape is the Breit-Wigner curve, about 2.5 GeV wide. The Z⁰ appears and decays almost instantly — most often into a spray of hadron jets, sometimes into a pair of muons.
What's real here — and what's a cartoon
The simulator is an accelerator and detector visualiser, not a physics engine that derives nature from first principles. Being straight about the line matters, so here it is.
Real:
- The beam steering, and the way each track curves —
r = p/(|q|·B), with momentum and charge doing exactly what they should. - The production thresholds (√s must clear twice a particle's mass) and the back-to-back geometry that conserves momentum.
- The Z⁰ resonance sitting at 91 GeV with a Breit-Wigner shape.
Illustrative:
- Which channel comes out of any single collision is sampled from realistic relative rates, not computed from quantum field theory — the real quantum probabilities are genuine research-grade calculations a canvas can't do live.
- The curvature and energy scales are compressed for on-screen visibility, so you can always see the bend. The relationships they show are honest; the absolute numbers aren't measurements.
Try it yourself
Open the particle collider simulator, hit Snap to Z⁰ (91 GeV), and watch the rate meter jump as jets fill the detector. Then slide the energy away from 91 and see the spike fade. Everything runs in your browser — nothing to install, no data leaves your machine.
Keep exploring the physics labs
- Charged Particle in a Magnetic Field — the same force that curves the collider's tracks, on a single charge you can steer.
- Double-Slit Experiment — the other half of the quantum story, where particles act like waves.
- All the physics labs — orbits, chaos, waves, fluids and more, each running real physics in the browser.