Physic Labs

Particle physics

The Standard Model: particles and interactions

Examine particle signatures through a layered detector (tracker, calorimeter, muon chamber) while varying momentum and field strength. Identify electron, muon, and hadron by their track patterns — the event-reading skill of particle physics.

Research

Equipment

  • 3D layered-detector model: tracker, calorimeter, muon chamber
  • «Change particle» button and Pause
  • Relative-momentum and magnetic-field sliders

Procedure

  1. Identify through detector layers

    Press «Change particle» through the species: electron (bends in the tracker, stops fully in the EM calorimeter), hadron (interacts as a shower in the hadronic calorimeter), muon (crosses everything, leaves a hit in the muon chamber), photon/neutrino (no track; the neutrino escapes). Record an identification table.

  2. Measure curvature for momentum

    For a charged particle, vary «Relative momentum»: the tracker path straightens as p grows — curvature radius r=p/(qB)r=p/(qB). Read r at two p settings and check proportionality; this is how real spectrometers «weigh» particle momentum.

  3. Vary the magnetic field

    At fixed momentum, raise «Relative magnetic field»: stronger B → tighter curvature, easier to measure but looping sooner; B = 0 → a straight line. Note the detector-design trade-off: strong fields (the ~2 T CMS solenoid at the LHC) to measure high-energy particles.

  4. Predict an unknown particle

    Press «Change particle» and hide the name display: guess the species from the track pattern before confirming. Extension: an uncharged particle (photon) leaves only a calorimeter hit without a track; the neutrino — the Standard Model's «ghost» — vanishes entirely, appearing in real events only as missing momentum pTmissp_T^{miss}.

Simulation

Experiment history

Particle detectors evolved from the bubble chamber (Glaser, 1952 — Nobel 1960) and multiwire proportional chamber (Charpak, 1968 — Nobel 1992) to the layered detector blocks at the LHC, where each event logs hundreds of millions of channels. The principle endures: a curved tracker measures momentum, calorimeters absorb energy, muon chambers filter penetrating particles. The Standard Model — assembled from Glashow–Weinberg–Salam (electroweak, Nobel 1979), Gell-Mann–Zweig (quarks), Yang–Mills (gauge theory), Englert–Brout–Higgs (mass generation, Nobel 2013) — describes three interactions and 17 fundamental particles; the Higgs boson was found by ATLAS/CMS in 2012 with exactly this signature-reading technique. What it leaves unexplained — neutrino masses, dark matter, matter–antimatter asymmetry — is the to-do list of physics beyond the Standard Model.

Related physicists

Paul DiracRichard FeynmanMurray Gell-MannSteven WeinbergMohammad Abdus SalamSheldon Lee GlashowPeter Ware HiggsFrançois EnglertChen Ning YangGeorges CharpakDonald Arthur Glaser

Related library topics

The Standard Model: particles and interactions