This minireview deals with some of the 0-＋ and 1＋＋ mesons reported in the 1200 1500 MeV region, namely the η（1405）, η（1475）, f1（1285） f1（1420）, a1（1420） and f1（1510）. The first observation of a pseudo...This minireview deals with some of the 0-＋ and 1＋＋ mesons reported in the 1200 1500 MeV region, namely the η（1405）, η（1475）, f1（1285） f1（1420）, a1（1420） and f1（1510）. The first observation of a pseudoscalar resonance around 1400 MeV - the 7（1440） - was made in pp annihilation at rest into η（1440）π＋π-,展开更多
I. Introduction： In contrast to the vector and tensor mesons, the identification of the scalar mesons is a long-standing puzzle. Scalar resonances are difficult to resolve because some of them have large decay widths...I. Introduction： In contrast to the vector and tensor mesons, the identification of the scalar mesons is a long-standing puzzle. Scalar resonances are difficult to resolve because some of them have large decay widths which cause a strong overlap between resonances and background. In addition, several decay channels sometimes open up within a short mass interval （e.g. at the KK and ηη thresholds）, producing cusps in the line shapes of the near-by resonances. Furthermore, one expects non-qq scalar objects, such as glueballs and multiquark states in the mass range below 2 GeV （for reviews see, e.g., Refs. [1-5] and the mini-review on non-qq states in this Review of Particle Physics （RPP））.展开更多
15.1. Quantum numbers of the quarks Quantum chromodynamics （QCD） is the theory of the strong interactions. QCD is a quantum field theory and its constituents are a set of fermions, the quarks, and gauge bosons, the...15.1. Quantum numbers of the quarks Quantum chromodynamics （QCD） is the theory of the strong interactions. QCD is a quantum field theory and its constituents are a set of fermions, the quarks, and gauge bosons, the gluons. Strongly interacting particles, the hadrons, are bound states of quark and gluon fields. As gluons carry no intrinsic quantum numbers beyond color charge, and because color is believed to be permanently confined, most of the quantum numbers of strongly interacting particles are given by the quantum numbers of their constituent quarks and antiquarks. The description of hadronic properties which strongly emphasizes the role of the minimum-quark-content part of the wave function of a hadron is generically called the quark model. It exists on many levels： from the simple, almost dynamics-free picture of strongly interacting particles as bound states of quarks and antiquarks, to more detailed descriptions of dynamics, either through models or directly from QCD itself. The different sections of this review survey the many approaches to the spectroscopy of strongly interacting particles which fall under the umbrella of the quark model.展开更多
The constituent quark model describes the observed meson spectrum as bound qq states grouped into SU（N） flavor multiplets （see our review on the ＇Quark Model＇ in this issue of the Review）. However, the self-coup...The constituent quark model describes the observed meson spectrum as bound qq states grouped into SU（N） flavor multiplets （see our review on the ＇Quark Model＇ in this issue of the Review）. However, the self-coupling of gluons in QCD suggests that additional mesons made of bound gluons （glueballs）, or qq-pairs with an excited gluon （hybrids）, may exist.展开更多
文摘This minireview deals with some of the 0-＋ and 1＋＋ mesons reported in the 1200 1500 MeV region, namely the η（1405）, η（1475）, f1（1285） f1（1420）, a1（1420） and f1（1510）. The first observation of a pseudoscalar resonance around 1400 MeV - the 7（1440） - was made in pp annihilation at rest into η（1440）π＋π-,
文摘I. Introduction： In contrast to the vector and tensor mesons, the identification of the scalar mesons is a long-standing puzzle. Scalar resonances are difficult to resolve because some of them have large decay widths which cause a strong overlap between resonances and background. In addition, several decay channels sometimes open up within a short mass interval （e.g. at the KK and ηη thresholds）, producing cusps in the line shapes of the near-by resonances. Furthermore, one expects non-qq scalar objects, such as glueballs and multiquark states in the mass range below 2 GeV （for reviews see, e.g., Refs. [1-5] and the mini-review on non-qq states in this Review of Particle Physics （RPP））.
文摘15.1. Quantum numbers of the quarks Quantum chromodynamics （QCD） is the theory of the strong interactions. QCD is a quantum field theory and its constituents are a set of fermions, the quarks, and gauge bosons, the gluons. Strongly interacting particles, the hadrons, are bound states of quark and gluon fields. As gluons carry no intrinsic quantum numbers beyond color charge, and because color is believed to be permanently confined, most of the quantum numbers of strongly interacting particles are given by the quantum numbers of their constituent quarks and antiquarks. The description of hadronic properties which strongly emphasizes the role of the minimum-quark-content part of the wave function of a hadron is generically called the quark model. It exists on many levels： from the simple, almost dynamics-free picture of strongly interacting particles as bound states of quarks and antiquarks, to more detailed descriptions of dynamics, either through models or directly from QCD itself. The different sections of this review survey the many approaches to the spectroscopy of strongly interacting particles which fall under the umbrella of the quark model.
文摘The constituent quark model describes the observed meson spectrum as bound qq states grouped into SU（N） flavor multiplets （see our review on the ＇Quark Model＇ in this issue of the Review）. However, the self-coupling of gluons in QCD suggests that additional mesons made of bound gluons （glueballs）, or qq-pairs with an excited gluon （hybrids）, may exist.
