The Top Quark

Abstract

The Standard Model requires the existence of a sixth or top quark to suppress transitions of the fifth or beauty quark found in 1974. Prospects for its discovery are considered in the light of recent results showing that the top's mass exceeds 89 GeV/c2.The quark model was proposed in 1964 [1] to describe the large number of strongly Interacting particles (hadrons) produced at high-energy accelerators in terms of a small number of elemen tary constituents. In its original formula tion, the model needed three quarks of spin 1/2 and baryon number 1/3: the u-quark, with electric charge +2/3 (in units of the proton charge), and two quarks with electric charge -1/3, na med d and s. These quarks together with their antiquarks u, d and s were sufficient to describe all known baryons and mesons, the baryons consisting of three quarks and the mesons of a quarkantiquark pair. The s and s quarks were needed to account for the strange ha drons, such as the K-mesons and the hyperons (A, Z, E, Ω, etc.).In the quark model, the weak decay of a hadron is described in terms of the weak decay of one of the constituent quarks. For example, the |3-decay of the neutron, which is a ddu system, is the result of the decay d → ue-ve of one of the two d-quarks. The final quark sys tem, duu, is the proton. Similarly, the β-decay of the A hyperon (a uds system) is described in terms of quark decay s → ue~ve, resulting in the observed decay A → pe-ve. Fourth and Fifth QuarksThe existence of weak s → u transi tions implied the occurrence of s -d transitions to second order in the weak interaction, as a result of an interme diate transition to a u-quark state (s → u, u → d). Such s -d transitions would result, for example, in the decays K° → µ + µ-or K+ → π + e + e _ which had not been observed experimentally in the 60's (such decays were later measured to occur at very low rates, representing

Formation of heavy quarks in ultrarelativistic heavy-ion collisions

“…Even the boosted LEP 2 collider with its 100 GeV on 100-GeV e + e -beam presumably will not provide the possibility to create heavy top quarks. At the Tevatron at Fermilab, the top quark can be detected if it is not heavier than m , = 120 GeV [6]. For a still heavier top quark, one has to wait until new colliders start to operate.…”

Hidden Higgs Particle

“…In this case the usual perturbation theory (PT), which is the only reliable method of calculation in quantum field theory (QFT), cannot be applied to derivation of the SM predictions. In the near future at the SSC and LHC the Higgs mass range M H ≤ 800 GeV will be exhaustively explored [3], [4] and the above-mentioned upper bound of the perturbative regime of the SM may be exceeded.…”

Christ and Community: A Socio-Historical Study of the Christology of Revelation

“…108Pliny, Letters 10; cf. Krodel,[30][31][32][33][34][35][36][37][38][39][40] notes that both this letter and the one to the Ephesians both mention Christ holding seven stars; both congregations have fallen; and both promise life (141).…”