Related papers: Hadronic event structure, power corrections and th…
Event shapes have long been used to extract information about hadronic final states and the properties of QCD, such as particle spin and the running coupling. Recently, a family of event shapes, the angularities, has been introduced that…
Experimental results on jet physics at LEP and SLC are reviewed and compared with perturbative QCD predictions. The discussion includes determinations of the strong coupling $\as$, measurements of event shape distributions and jet cross…
The amplitudes for $2\rightarrow 2$ scattering processes involving longitudinally polarized gauge bosons $( W_L^\pm, Z_L )$ and the Higgs boson are analyzed up to two loops. Assuming $M_H >> M_W$, the trilinear Higgs coupling, $\lambda v$,…
We investigate hysteresis effects in the perturbative solution of renormalisation group equations (RGEs). We present examples for the QCD running coupling and proton's parton distribution functions (PDFs), relevant to precision physics at…
The quartic gauge coupling (QGC) of the electroweak interaction can be used as a probe for physics beyond the Standard Model and has been previously measured at the Large Hadron Collider. However, to achieve sensitivity to small deviations…
The construction of heavy quark effective field theory (HqEFT) is extended to arbitrary order in both expansion parameters $\alpha_s$ and $1/m_q$. Matching conditions are discussed for the general case, and it is verified that this approach…
The QCD coupling, $\alpha_s$, is not a physical observable since it depends on conventions related to the renormalization procedure. Here we discuss a redefinition of the coupling where changes of scheme are parametrised by a single…
After a brief historical review of the emergence of QCD as the quantum field theory of strong interactions, the basic notions of colour and gauge invariance are introduced leading to the QCD Lagrangian. The second lecture is devoted to…
Hadronic antenna patterns can provide a valuable diagnostic tool for probing the origin of the apparent excess of high $x,Q^2$ events at HERA. We present quantitative predictions for the distributions of soft particles and jets in standard…
New strong interactions at the LHC may exhibit a richer structure than expected from simply rescaling QCD to the electroweak scale. In fact, a departure from rescaled QCD is required for compatibility with electroweak constraints. To…
We point out that a study of event shapes at hadron colliders allows to explore novel aspects of QCD. These studies are today made easier by the development of a program which automates the resummation.
The normalization of the gluon condensate and of renormalon-related power corrections in QCD is computed under the assumption that their ``perturbative'' part dominates over any eventual extra contribution from the non-trivial vacuum. The…
Several preliminary QCD results from e+e- interactions at LEP are reported. These include studies of event shape variables, which are used to determine alpha_s and for studies of the validity of power corrections. Further, a study of color…
The Quantum Chromodynamics (QCD) coupling $\alpha_s$ is a central parameter in the Standard Model of particle physics. However, it depends on theoretical conventions related to renormalisation and hence is not an observable quantity. In…
Heavy quarks provide a new dimension to QCD, allowing tests of fundamental theory, the nature of color confinement, and the production of new exotic multiquark states. I also discuss novel explanations for several apparently anomalous…
Recent theory progresses in (3+1)D dynamical descriptions of relativistic nuclear collisions at finite baryon density are reviewed. Heavy-ion collisions at different collision energies produce strongly coupled nuclear matter to probe the…
While the hard phase of the strong interaction is well described by perturbative QCD, the soft hadronization phase is less understood. Benefiting from the high statistics from e+e- experiments at the Z0 resonance, it is possible to impose…
Perturbative QCD (pQCD) running coupling a(Q^2) (=alpha_s(Q^2)/pi) is expected to get modified at low spacelike momenta 0 < Q^2 < 1 GeV^2 so that, instead of having unphysical (Landau) singularities it remains smooth and finite there, due…
High energy diffraction and soft QCD span exciting final state topologies and fluctuations which have not yet been measured or characterized in a fully exhaustive way. In this work, we go beyond the standard measures and formulate a new…
We estimate the effects of non-perturbative physics on the differential distributions of infrared- and collinear-safe $e^+e^-$ event shape variables, by extending the notion of an infrared-regular effective strong coupling, which accounts…