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.V. D. Barger, R. J. N. Phillips (1997) “Collider Physics” Frontier in Physics, Addison-Wesley Publishing Company, Inc.M. Dasgupta and G. P. Salam (2004),

[https://iopscience.iop.org/article/10.1088/0954-3899/30/5/R01 Event shapes in e+ e- annihilation and deep inelastic scattering],

J. Phys. G 30, R143, [https://arxiv.org/abs/hep-ph/0312283 preprint]

The most common event shape observables include:

• The sphericity;

• The aplanarity;

• The thrust.

• The C-parameter;

• The jet broadening.