ar X iv : h ep - p h / 06 07 07 7 v 2 1 5 Ja n 20 07 On the existence of heavy tetraquarks 1

ar X iv : h ep - p h / 06 07 07 7 v 1 7 J ul 2 00 6 On the existence of heavy tetraquarks 1

Previous work done in collaboration with David Brink is reviewed in the light of the recent observation of new charmonium-like resonances which can be interpreted as tetraquarks. In the framework of a schematic quark model the spectrum of cc̄qq̄ tetraquarks is presented. Based on a talk given at the 11th International Conference on Nuclear Reaction Mechanisms, Varenna (Italy), June 12-16, 2006 2 ...

ar X iv : h ep - p h / 06 01 20 7 v 1 2 5 Ja n 20 06 Heavy - Quark Form Factors and Threshold Cross Section at O ( α 2 S )

During the last year, analytic expressions for the two-loop QCD corrections to the form factors for the vector, axial-vector, scalar and pseudo-scalar vertices involving a pair of heavy quarks, QQ̄, were calculated. The results are valid for arbitrary momentum transfer and mass of the heavy quarks. These form factors have a number of applications, including anomalous couplings, the e+e− → QQ̄ cro...

ar X iv : h ep - p h / 00 09 23 7 v 3 2 9 Ja n 20 01 “ Bottom - up ” thermalization in heavy ion collisions

We describe how thermalization occurs in heavy ion collisions in the framework of perturbative QCD. When the saturation scale Q s is large compared to Λ QCD , thermalization takes place during a time of order α −13/5 Q −1 s and the maximal temperature achieved is α 2/5 Q s .

ar X iv : h ep - p h / 06 09 07 7 v 1 7 S ep 2 00 6 Hadron multiplicities in e + e − annihilation with heavy primary quarks

ar X iv : h ep - t h / 06 12 12 9 v 3 1 1 Ja n 20 07 STRING COSMOLOGY