1,721,242 research outputs found
Progress in small x resummation
No full textI review recent theoretical progress in the resummation of small x contributions to the evolution of parton distributions, in view of its potential significance for accurate phenomenology at future colliders. I show that a consistent perturbative resummation of collinear and energy logs is now possible, and necessary if one wishes to use recent NNLO results in the HERA kinematic region
Parton distributions at the dawn of the LHC
No full textWe review basic ideas and recent developments on the determination
of the parton substructure of the nucleon in view of applications to precision
hadron collider physics. We review the way information on PDFs
is extracted from the data exploiting QCD factorisation, and discuss the
current main two approaches to parton determination (Hessian and Monte
Carlo) and their use in conjunction with different kinds of parton parameterisation.
We summarise the way different physical processes can be used
to constrain different aspects of PDFs. We discuss the meaning, determination
and use of parton uncertainties. We briefly summarise the current
state of the art on PDFs for LHC physics
Structure functions and parton distributions
No full textI review recent progress in the determination of the parton structure of the nucleon, in particular from deep-inelastic structure functions. I explain how the needs of current and future precision phenomenology; specifically at the LHC, have turned the determination of parton distributions into a quantitative problem. I describe the results and difficulties of current approaches and ideas to go beyond them
The Cellular Automaton Interpretation of Quantum Mechanics, Gerard ’t Hooft, Springer, 2016. $59.99 (298 pp.). ISBN 978-3-319-41284-9
No full textProgress in the determination of the partonic structure of the proton
No full textWe review the state of the art of the determination of the parton substructure of the nucleon, as expressed in terms of parton distribution functions (PDFs) and probed in high-energy lepton–hadron and hadron–hadron collisions. We also assess their implications for current precision collider phenomenology, in particular at the Large Hadron Collider (LHC). We review the theoretical foundations of PDF determination: how cross sections are expressed in terms of PDFs by use of perturbative QCD factorization and evolution, the methodology used to extract PDFs from experimental data, and how different physical processes can be used to constrain different PDFs. We summarize current knowledge of PDFs and the limitations in accuracy that this knowledge currently entails for the computation of hadron collider processes, in particular at the LHC. We discuss the current main sources of theoretical and phenomenological uncertainties and the direction of progress toward their reduction in the future
Geometric scaling from Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution
No full textWe show that the geometric scaling of the total virtual photon-proton cross section data can be explained using standard linear Dokshitzer-Gribov-Lipatov-Altarelli-Parisi perturbative evolution with generic boundary conditions in a wide kinematic region. This allows us to single out the region where geometric scaling may provide evidence for parton saturatio
Spin in quantum field theory
No full textI introduce spin in field theory by emphasizing the close connection between quantum field theory and quantum mechanics. First, I show that the spinstatistics connection can be derived in quantum mechanics without relativity or field theory. Then, I discuss path integrals for spin without using spinors. Finally, I show how spin can be quantized in a path-integral approach, without introducing anticommuting variables
- …
