skalármez

Skalármez, in particle physics often called a scalar meson, is a meson with total angular momentum J = 0 and positive parity, J^P = 0^+. Scalar mesons are bosons composed predominantly of a quark–antiquark pair, though many candidates may have more complex substructures such as tetraquark states or meson–meson molecular configurations. They form the lightest nonet of mesons in some quark models, and commonly include the isovector a0(980) and the isoscalars f0(500) (sigma) and f0(980), together with a strange partner such as K0*(1430). The lightest f0(500) is notably broad, with a controversial exact mass. Scalar mesons decay mainly into pairs of lighter pseudoscalar mesons, for example pi pi, KK, or eta pi, and are observed in hadron decays and in scattering experiments.

In quantum chromodynamics, scalar mesons are important for understanding chiral symmetry breaking and the generation of hadron masses. They are subjects of competing interpretations: conventional quark–antiquark states, tetraquark configurations, molecular bound states, or mixtures with glueball components, especially at higher masses. Their experimental study is challenging due to broad widths and overlapping resonances, requiring sophisticated partial-wave analyses.

Skalármez remains a central topic in hadron spectroscopy, illustrating the complexity of the light meson sector and tests of nonperturbative QCD.