Heavy flavours: theory summary

I summarize the theory talks given in the Heavy Flavours Working Group. In particular, I discuss heavy-flavour parton distribution functions, threshold resummation for heavy-quark production, progress in fragmentation functions, quarkonium production, heavy-meson hadroproduction.Comment: 6 pages. Talk given at DIS 2005, XIII Workshop on Deep Inelastic Scattering, April 27-May 1, 2005, Madison, WI, U.S.

Heavy Flavours at LEP

This paper describes recent developments in Heavy Flavour physics at LEP, focusing on a new result from the ALEPH Collaboration on the search for flavour oscillations of the Bs meson. The impact of this analysis on the world combination and the resulting limit on the Bs oscillation frequency are discussed.Comment: 6 pages, 7 Encapsulated Postscript figures, uses pennames.sty, to be published in the proceedings of Rencontres de Moriond 2002 Electroweak Interactions and Unified Theorie

Heavy Flavours at Colliders

I review some topics in the production and decays of heavy flavours that are relevant for collider physics. In particular, I discuss the present status and some recent progress related to masses, parton densities and fragmentation functions of heavy quarks, as well as threshold resummation, polarized onium production at high transverse momentum, and a factorization theorem for $B \to\pi\pi$ decays.Comment: 12 pages. Plenary talk given at UK Phenomenology Workshop on Collider Physics, Durham, England, 19-24 Sep 1999 Comments and references adde

Heavy flavours

The paper introduces the selection of new results on heavy flavours presented at the QCD and High Energy Interactions section of the XLIIIth ``Rencontres de Moriond'' conference.Comment: Talk given at the QCD section of "Rencontres de Moriond

Walking in the SU(N)

We study the phase diagram as function of the number of colours and flavours of asymptotically free non-supersymmetric theories with matter in higher dimensional representations of arbitrary SU(N) gauge groups. Since matter in higher dimensional representations screens more than in the fundamental a general feature is that a lower number of flavours is needed to achieve a near-conformal theory. We study the spectrum of the theories near the fixed point and consider possible applications of our analysis to the dynamical breaking of the electroweak symmetry.Comment: 12 page

Determining the conformal window: SU(2) gauge theory with N_f = 4, 6 and 10 fermion flavours

We study the evolution of the coupling in SU(2) gauge field theory with $N_f=4$, 6 and 10 fundamental fermion flavours on the lattice. These values are chosen close to the expected edges of the conformal window, where the theory possesses an infrared fixed point. We use improved Wilson-clover action, and measure the coupling in the Schr\"odinger functional scheme. At four flavours we observe that the couping grows towards the infrared, implying QCD-like behaviour, whereas at ten flavours the results are compatible with a Banks-Zaks type infrared fixed point. The six flavour case remains inconclusive: the evolution of the coupling is seen to become slower at the infrared, but the accuracy of the results falls short from fully resolving the fate of the coupling. We also measure the mass anomalous dimension for the $N_f=6$ case.Comment: 22 pages, 12 figures. Proof readin