Related papers: Low x phenomena
Invited talk presented at the 1994 Meeting of The Division of Particles and Fields of the American Physical Society, Albuquerque NM, August 1-6, 1994
The study of gluon radiation in QCD, in the limit of small ("soft") momentum, remains an active research area, with a variety of phenomenological and theoretical applications. Soft gluon emission leads to large logarithms in perturbation…
We review some outstanding puzzles and experimental anomalies in hadron physics that appear to challenge conventional wisdom and, in some cases, the foundations of QCD. We also discuss possible solutions and propose new tests and…
Part I is devoted to the extraction of the QCD coupling from a bound state approach at low energy scales, where unphysical singularities make the RG-improved pQCD useless. Theoretical results on the meson spectrum based on a Bethe-Salpeter…
Scaling violation of inclusive jet production at small-$x$ in hadron scattering with increasing total collision energy is discussed. Perturbative QCD based on the factorisation theorem for hard processes and GLAPD evolution equations…
Among the prominent low-mass dark matter candidates is the QCD axion but also other light and weakly interacting particles beyond the Standard Model. We review briefly the case for such dark matter and give an overview on most recent…
We argue that at sufficiently small Bjorken $x$ where pQCD amplitude rapidly increases with energy and violates probability conservation the shadowing effects in the single-scale small $x$ hard QCD processes can be described by an effective…
These lecture notes focus on the bound state sector of QCD. Motivated by data which suggests that the strong coupling \alpha_s(Q) freezes at low Q, and by similarities between the spectra of hadrons and atoms, I discuss if and how QCD bound…
The recent development of perturbative QCD (PQCD) fragmentation functions has strong impact on quarkonium production. I shall summarize $B_c$ meson production based on these PQCD fragmentation functions, as well as, the highlights of some…
The QCD expectations for the behaviour of the deep inelastic scattering structure functions in the region of small values of the Bjorken parameter $x$ are summarized. The Balitzkij, Lipatov, Fadin, Kuraev (BFKL) equation which sums the…
Recent results in soft QCD at LHC by the ATLAS, CMS and TOTEM Collaborations are presented. Special focus is reserved to studies in diffractive and forward physics, and to the underlying event, with comparison with previous results and…
We review recent developments in the perturbative QCD approach to exclusive hadronic B meson decays. We discuss the important next-to-leading-order corrections to B -> pi K, pi pi, and the penguin-dominated B -> PV modes, where P (V) is a…
The low energy mass spectrum of QCD in the large $N_C$ limit is computed. The low-lying states in the meson spectrum are explicitly evaluated up to the fourth order in the strong coupling perturbative expansion. The 't Hooft limit is smooth…
Chiral quark models offer a practical and simple tool to describe covariantly both low and high energy phenomenology in combination with QCD evolution. This can be done in full harmony with chiral symmetry and electromagnetic gauge…
A simple parametrization of the QCD running coupling at low scales is introduced and used to illustrate various schemes for the estimation of non-perturbative power corrections. The `infrared matching' scheme proposed earlier gives…
We present a specific class of models for an infrared-finite analytic QCD coupling, such that at large space-like energy scales the coupling differs from the perturbative one by less than any inverse power of the energy scale. This…
A status report is given of some recent theoretical and experimental investigations looking for signals of Lorentz violation in QED. Experiments with light, charged particles, and atoms have exceptional sensitivity to small shifts in energy…
We report on recent advances in the understanding of non-perturbative phenomena in the quantum theory of fields and strings.
I give a brief overview of the status of lattice QCD, concentrating on topics relevant to phenomenology. I discuss the calculation of the light quark spectrum, the lattice prediction of $\alpha_\MS(M_Z)$, and the calculation of $f_B$.
We discuss recent results of hadron spectroscopy and hadron-hadron interaction within a quark model framework. New experimental data could point to the important role played by higher order Fock space components on low-energy observables.…