The nuclear quadrupole moment of In has been determined by combining the experimental nuclear quadrupole coupling constants and electric field gradients, calculated at the four-component CCSD~T! level of theory, of four indium halides. Our recommended value for the nuclear quadrupole moment of In is 770~8! millibarn. A basis set study at the Dirac–Hartree–Fock level shows a slow convergence of ...

We analyze the allowed spectrum of electric and magnetic charges carried by dyons in (toroidally compactified) heterotic string theory in four dimensions at arbitrary values of the string coupling constant and θ angle. The spectrum is shown to be invariant under electric-magnetic duality transformation, thereby providing support to the conjecture that this is an exact symmetry in string theory.

A review is given of the latest results on jet production and studies of event shape variables in deep inelastic scattering at HERA. Jet cross sections studies for inclusive jet and dijet events are presented and compared to next-to-leading order QCD calculations. Extraction of the strong coupling constant αs is discussed.

We study matrix string scattering amplitudes and matrix string instantons on a marked Riemann surface in the limit of a vanishing string coupling constant. We give an explicit parameterization of the moduli space of such instantons. We also give a description of the set of fermionic supermoduli. The integration over the supermoduli leads to the inclusion of picture changing operators at the int...

Results are presented of a study of the experimental and theoretical accuracy one may achieve at HERA in measuring the strong coupling constant αs and the gluon distribution from scaling violations of F2 structure functions.

The supersymmetry breaking parameters and the resulting supersymmetric particle spectrum are studied in orbifold compactifications of string theory under the assumption that unification of gauge coupling constants at about 10 16 GeV is a consequence of large moduli dependent string loop threshold corrections. The effect on the spectrum of various assumptions as to the modular weights of the sta...

The bulk of large radiative corrections to any process can be obtained by promoting coupling constants to be running ones and by including QED radiation at the leading logarithmic level via structure functions evoluted at some scale. The problem of fixing the proper scale in running coupling constants and in structure functions for non-annihilation processes is briefly addressed and the general...

We show that contrary to first expectations realistic three generation supersymmetric intersecting brane world models give rise to phenomenologically interesting predictions about gauge coupling unification. Assuming the most economical way of realizing the matter content of the MSSM via intersecting branes we obtain a model independent relation among the three gauge coupling constants at the s...

Hadronic decays of the τ lepton provide a clean environment to study hadron dynamics in an energy regime dominated by resonances, with the interesting information captured in the spectral functions. Recent results from ALEPH on exclusive channels are presented, with some emphasis on the ππ final state which plays a crucial role for the determination of the hadronic contribution to the muon anom...

In this talk we summarize main results of a recent determination of the polarized deeply inelastic parton distributions to NLO from the world data. In the analysis the LO and NLO parton densities and their 1σ statistical errors were derived and parameterized. The strong coupling constant αs(M 2 Z) is determined αs(M 2 Z) = 0.113±0.004(stat.)± 0.004(fac.)+0.008/−0.005(ren.) Comparisons of the lo...