Smash particles together in your browser. An electron and a positron counter-rotate around a particle accelerator and cross at the interaction point; the collision sprays particles into a detector, where every charged track curves in the magnetic field — its radius reads off the momentum, and opposite charges bend opposite ways. Slide the collision energy √s to change what can be produced — back-to-back muons, jets of hadrons, or two photons — and crank it to 91 GeV to light up a real Z⁰ boson. It's the same force that steers our charged particle in a magnetic field, turned into a collider.
Collide beams · slide the energy · snap to the Z⁰ at 91 GeV
e⁻ beame⁺ beammuonhadron jetphoton
Collision energy √s30 GeV
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Collisions0
Production rate
A collider turns energy into matter, then reads the debris by how it bends. Einstein's E = mc² runs in reverse here: pour enough energy into a head-on e⁺e⁻ collision and it materializes as new particles — but only those light enough that √s clears twice their mass. What flies out is identified in the detector by its track: charged particles curve in the field with radius r = p/(|q|·B), so the bend measures momentum and its direction measures the sign of the charge, while neutral particles leave no track and show up only as energy in the calorimeter. Tune √s to 91 GeV and a real Z⁰ boson appears as a sharp spike in the collision rate — the resonance that early electron–positron colliders were built to study.
How It Works
Accelerate, collide, and read the tracks — the three jobs of a real collider experiment.
1
Accelerate on the ring
An electron and a positron circulate the particle accelerator in opposite directions. Because they carry opposite charge, the same ring of bending magnets steers them the opposite way round, so a single machine runs both beams and brings them together at the interaction point. Real rings top up the energy each lap with radio-frequency cavities — the pulsing marker at the top of the ring.
2
Collide head-on
When the bunches cross, their energy — the centre-of-mass energy √s you set — can turn into new particles by E = mc². A channel is chosen from the real possibilities at that energy: two back-to-back muons, a spray of hadron jets, or two photons. A particle can only be made if √s exceeds twice its mass, and near 91 GeV a real Z⁰ resonance makes collisions far more likely.
3
Read the detector
The products fan out from the centre. Each charged track has its velocity rotated by the exact gyro-angle every step — a Boris-style update for the detector's field — so it curves with radius r = p/(|q|·B): fast tracks run almost straight, slow ones curl, and + and − bend opposite ways. Neutral particles fly straight and light only the calorimeter ring. That is exactly how experiments tell one particle from another.
Is this really how a particle collider works?
This particle collider is an accelerator plus event-display simulator, and the visible mechanics are real. Two counter-rotating beams are held on a ring by bending magnets and brought together at an interaction point; the products fan out into a layered detector and their tracks curve in a magnetic field so the curvature reveals each particle's momentum and charge. What a canvas cannot do is compute the quantum probabilities of what comes out — that is quantum field theory. So the choice of channel each collision (muons, hadron jets or photons) is sampled from realistic relative rates rather than derived from first principles, while everything you watch happen to the particles obeys the real physics.
Why do the two tracks curve in opposite directions?
Because the detector's magnetic force on a moving charge, q·v×B, points the opposite way when the charge flips sign. A positive particle and its negative antiparticle fly out back-to-back to conserve momentum, and the same field then bends one clockwise and the other counter-clockwise. The bending radius is r = p/(|q|·B): the higher a particle's momentum, the gentler its curve — which is exactly how real detectors measure momentum from the curvature of a track. It's the same steering you can explore in the charged-particle lab.
What happens at √s ≈ 91 GeV, and what is the Z⁰ boson?
The Z⁰ is the neutral carrier of the weak force, with a mass of about 91 GeV. When the collision energy √s is tuned to that value the electron and positron can annihilate into a real Z⁰, and the production rate spikes by a huge factor — a resonance whose shape is described by the Breit-Wigner curve, about 2.5 GeV wide. The rate meter in the simulator climbs steeply as you slide toward 91 GeV. The Z⁰ then decays almost at once, most often into a spray of hadron jets and sometimes into a pair of muons — the same channels the continuum produces, but far more of them. This is essentially what an electron–positron collider does with its energy sitting right on the Z⁰ resonance.
Why do the photons leave no curving track?
Photons are electrically neutral, so the magnetic force q·v×B is zero for them — nothing bends their path and they travel in a straight line. They also leave no trail in the tracking layers, which only sense charge. Instead a photon dumps its energy in the calorimeter, the outer ring, producing a localized deposit rather than a track. Telling neutral particles from charged ones this way — straight-and-only-in-the-calorimeter versus curved-in-the-tracker — is one of the core jobs of a real detector.
Learn More
Authoritative references to go deeper than the simulation.
Particle accelerator· Wikipedia How real accelerators work, from linear accelerators to circular storage rings.
W and Z bosons· Wikipedia The carriers of the weak force, including the Z⁰ and its mass of about 91 GeV.
Particle Data Group· pdg.lbl.gov The definitive reference tables for particle masses, lifetimes and properties.
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