Article · Wikipedia archive · Last revised Jun 13, 2026

Event shape observables

In high energy physics, event shapes observables are quantities used to characterize the geometry of the outcome of a collision between high energy particles in a collider. Specifically, event shapes observables quantify the general pattern traced by the trajectories of the particles resulting from the collision.

Last revised
Jun 13, 2026
Read time
≈ 1 min
Length
105 w
Citations
2
Source

In high energy physics, event shapes observables are quantities used to characterize the geometry of the outcome of a collision between high energy particles in a collider. Specifically, event shapes observables quantify the general pattern traced by the trajectories of the particles resulting from the collision.12

The most common event shape observables include:

  • The sphericity;
  • The aplanarity;
  • The C-parameter;
  • The jet broadening.
References

References

  1. V. D. Barger, R. J. N. Phillips (1997) “Collider Physics” Frontier in Physics, Addison-Wesley Publishing Company, Inc.
  2. M. Dasgupta and G. P. Salam (2004), Event shapes in e+ e- annihilation and deep inelastic scattering, J. Phys. G 30, R143, preprint