Anomalous Quantum Hall Effect on Sphere

We study the anomalous quantum Hall effect exhibited by the relativistic particles living on two-sphere S^2 and submitted to a magnetic monopole. We start by establishing a direct connection between the Dirac and Landau operators through the Pauli--Schr\"odinger Hamiltonian H_{s}^{SP}. This will be helpful in the sense that the Dirac eigenvalues and eigenfunctions will be easily derived. In analyzing H_{s}^{SP} spectrum, we show that there is a composite fermion nature supported by the presence of two effective magnetic fields. For the lowest Landau level, we argue that the basic physics of graphene is similar to that of two-dimensional electron gas, which is in agreement with the planar limit. For the higher Landau levels, we propose a SU(N) wavefunction for different filling factors that captures all symmetries. Focusing on the graphene case, i.e. N=4, we give different configurations those allowed to recover some known results.Comment: 23 pages, clarifications, references added, misprints corrected. Version to appear in NP

A measurement of the photon structure function F-2(gamma) at an average Q(2) of 12 GeV2/c(4)

The hadronic photon structure function F-2(gamma) has been measured in the Q(2) range from 4 to 30 GeV2/c(4) and down to x values of order 0.001, using data taken with the DELPHI detector at LEP between 1991 and 1993. A comparison is made with several F-2(gamma) parameterizations with special emphasis on their low rr: behaviour. A result on the Q(2) evolution of F-2(gamma) is presented