ar X iv : h ep - p h / 03 08 18 0 v 1 1 8 A ug 2 00 3 Phenomenology of New Physics 1 LMU 17 / 03 August 2003 Gudrun

ar X iv : h ep - p h / 03 08 31 8 v 1 2 9 A ug 2 00 3 On the structure of the scalar and D mesons

The qq spectrum is studied within a chiral constituent quark model. It provides with a good fit of the available experimental data from light (vector and pseudoscalar) to heavy mesons. The new D states measured at different factories are studied. The 0 ++ light mesons are analyzed as q ¯ q pairs or tetraquark structures.

ar X iv : h ep - t h / 03 08 14 1 v 1 2 1 A ug 2 00 3 PARALLELISABLE HETEROTIC BACKGROUNDS

We classify the simply-connected supersymmetric parallelisable backgrounds of heterotic supergravity. They are all given by parallelised Lie groups admitting a bi-invariant lorentzian metric. We find examples preserving 4, 8, 10, 12, 14 and 16 of the 16 supersymmetries.

ar X iv : h ep - p h / 03 07 03 8 v 1 2 J ul 2 00 3 1 Scalar meson exchange in Φ → P 0 P 0 γ decays ∗

ar X iv : h ep - p h / 03 08 18 3 v 1 1 8 A ug 2 00 3 Aspects of Diffraction at the Tevatron

Results on soft and hard diffraction obtained by the CDF Collaboration at the Fermilab Tevatron p̄p Collider are reviewed with emphasis on aspects of the data that point to the underlying QCD mechanism for diffraction. The results are interpreted in terms of a phenomenological approach in which diffraction is due to an exchange of low-x partons subject to color constraints.

ar X iv : h ep - p h / 03 08 11 6 v 1 1 1 A ug 2 00 3 Dijet cross sections in ep collisions : who is afraid of symmetric cuts ?

Three widely used scenaria for defining cuts on transverse energies of jets in ep collisions are discussed. All of them are shown to suffer from the same sort of unphysical behaviour when the cut regions are subject to additional constraints. This feature is inherent in the very way dijet cross sections are defined and cannot be avoided. In particular, the symmetric cut scenario is shown to be ...