ar X iv : h ep - p h / 01 04 25 3 v 3 2 5 M ay 2 00 1 Production of the η b ( nS ) states 1

ar X iv : h ep - p h / 04 05 03 9 v 1 5 M ay 2 00 4 η , η ′ → π + π − γ with coupled channels

ar X iv : h ep - p h / 01 05 03 3 v 1 3 M ay 2 00 1 Threshold η and η ′ electroproduction off nucleons 1

The electroproduction of η and η ′ mesons on the proton and the neutron is investigated at tree level within the framework of U (3) chiral perturbation theory. In addition to the Born terms low-lying resonances such as the vector mesons and J P = 1/2 + , 1/2 − baryon resonances are included explicitly and their contributions are calculated. Results for the separated differential cross sections ...

ar X iv : h ep - p h / 04 05 11 9 v 1 1 3 M ay 2 00 4 The Lorentz and CPT violating effects on the charged

ar X iv : h ep - p h / 01 04 25 3 v 5 2 3 O ct 2 00 1 Production of the η b ( nS ) states

The rates for magnetic dipole (M1) transitions Υ(nS) → ηb(n S) + γ, n ≤ n, are compared. The photon energies for allowed (n = n) M1 transitions are very small, so hindered (n < n) transitions could be more favorable for discovering the ηb(1S, 2S). The question then arises whether Υ(2S) or Υ(3S) is a better source of ηb(1S). Whereas one nonrelativistic model favors ηb(1S) production from Υ(2S), ...

ar X iv : h ep - p h / 02 05 25 5 v 1 2 2 M ay 2 00 2 Production of singlet P - wave cc̄ and bb̄ states 1

No spin-singlet bb̄ quarkonium state has yet been observed. In this paper we discuss the production of the singlet P-wave bb̄ and cc̄ P1 states hb and hc. We consider two possibilities. In the first the P1 states are produced via the electromagnetic cascades Υ(3S) → ηb(2S)+γ → hb+γγ → ηb+γγγ and ψ → η c+γ → hc+γγ → ηc+γγγ. A more promising process consists of single pion transition to the P1 state...