GenParticle

GenParticle is a fundamental concept in particle physics simulation, particularly within the context of high-energy physics experiments. It represents a single particle in a simulated event, carrying essential information about its identity and properties. A GenParticle object typically stores the particle's type, often identified by its PDG (Particle Data Group) code, which uniquely specifies the particle species (e.g., electron, muon, photon, proton).

Beyond its type, a GenParticle also holds its kinematic information. This includes its momentum, usually represented as a three-vector (px, py, pz), and its energy. From these, other properties like mass and velocity can be derived. GenParticle objects are crucial for reconstructing the entire simulated event, allowing physicists to study the interactions and decays of particles produced in collisions.

Furthermore, GenParticle often includes information about the particle's origin and daughter particles. This is vital for understanding decay chains and tracing the history of particles within the simulation. For instance, a GenParticle might store pointers or indices to its mother particle and any subsequent daughter particles it decays into. This hierarchical structure is essential for simulating complex event topologies and performing detailed analyses. The precise attributes of a GenParticle can vary slightly depending on the specific simulation framework or software package being used, but its core role as a fundamental unit of particle information remains consistent.