CPsymmetria

CPsymmetria is a theoretical construct in particle physics describing a generalized CP-like symmetry that acts on both spacetime coordinates and internal quantum numbers. Unlike conventional CP, which combines charge conjugation (C) and parity (P), CPsymmetria incorporates a unitary transformation in flavour or gauge space. In field theory, a generalized CP transformation maps a set of fields φ_i(x) to X_ij φ_j^*(t, −x), where X is a unitary matrix encoding internal mixing. The transformation is a symmetry of the Lagrangian if the couplings obey consistency relations with X, yielding CP-invariance constraints on masses, Yukawa couplings, and scalar potentials.

Applications arise in models with multiple scalar fields or nontrivial flavour symmetries. CPsymmetria provides a framework to discuss when a theory is CP-symmetric and how CP violation can emerge. If the Lagrangian and vacuum preserve the generalized CP transformation for a given X, the model is CP-conserving; violations can arise through complex vacuum expectation values or through parameters incompatible with X. In some scenarios, CPsymmetria can be spontaneously broken by vacuum alignment, producing CP-violating phases without explicit complex couplings.

Status: In theoretical physics, generalized CP symmetry is a standard tool for organizing parameters and deriving predictions in flavour and Higgs sectors. The term CPsymmetria is used informally in some discussions to emphasize the matrix-structured nature of the symmetry; it is not a universally adopted formal label. Experimental CP-violation measurements in quark and lepton sectors test the consequences of these generalized constraints.

See also: CP violation, generalized CP symmetry, flavour symmetry, multi-Higgs-doublet models, neutrino mixing.