The associated production of a W boson and a single charm quark (W+c) is the only process in proton-proton collisions that directly probes the strange quark content of the proton. In this thesis, W+charm production is measured in proton-proton collisions at the LHC at 13 TeV, as recorded by the Compact Muon Solenoid (CMS) experiment. The analysis focuses on the identification of W bosons in their leptonic decay to a muon and a neutrino and charm quarks are tagged via the full reconstruction of D*-Mesons. The measured cross sections of W+c production are used, in combination with other relevant CMS results and the most precise HERA DIS data, in a QCD analysis to determine the strange quark content of the proton. The resulting strange quark distribution and suppression, with respect to the other light sea quarks, are in good agreement with those obtained in neutrino scattering experiments and extend their kinematic reach.

In this thesis, the first measurement of the running of the top quark mass is presented. This is a fundamental quantum effect that had never been studied before. Any deviation from the expected behaviour can be interpreted as a hint of the presence of physics beyond the Standard Model. All relevant aspects of the analysis are extensively described and documented. This thesis also describes a simultaneous measurement of the inclusive top quark-antiquark production cross section and the top quark mass in the simulation. The measured cross section is also used to precisely determine the values of the top quark mass and the strong coupling constant by comparing to state-of-the-art theoretical predictions. All the theoretical and experimental aspects relevant to the results presented in this thesis are discussed in the initial chapters in a concise but complete way, which makes the material accessible to a wider audience.

This volume focusses on four main topics: structure functions, tests of quantum chromodynamics, physics at the highest Q2 and p2T, and high energy scattering and diffraction. Comprehensive review articles on hadronic and photon structure, lepton-parton and parton-parton physics as well as future experimental opportunities are presented, together with a special lecture on HERA's legacy after the first decade of operation.

The proceedings of DIS 2001 present the most updated status of deep inelastic scattering (DIS) physics. Topics like structure function measurements and phenomenology, QCD studies in DIS and photoproduction, spin physics and diffractive interactions are reviewed in detail, with emphasis on those studies that push the test of QCD and the Standard Model to the limits of their present range of validity, towards both the very high and the very low four-momentum transfers in the lepton-proton scattering. Moreover, this workshop coincided with the transition between the first period of experimentation at the HERA ep collider at DESY and the start of the updated HERA II operation -- allowing a review of what has been learned up to now and a discussion on the main future directions of research in this field.

The first precision measurements on CP violation in the B system are reported. Both the BELLE and the BABAR collaboration presented, among others, results for sin 2ß with much improved accuracy. Results from the Sudbury Neutrino Observatory, SNO, also deserve to be mentioned. The convincing evidence of solar neutrino oscillations had been presented by SNO prior to the conference; a full presentation was given at the conference. An incredibly precise measurement of the anomalous magnetic moment of the muon is reported, a fresh result from the Brookhaven National Laboratory. Apart from these distinct physics highlights, there are also the first results from the new Tevatron run and from the relativistic heavy ion collider RHIC. Theorists write of our ever better understanding of the Standard Model and of what might lie beyond. Risky as it is to highlight only a couple of exciting subjects, it is merely meantto whet the appetite for further reading.

These proceedings present the most up-to-date status of deep inelastic scattering (DIS) physics. Topics such as structure function measurements and phenomenology, quantum chromodynamics (QCD) studies in DIS and photoproduction, spin physics and diffractive interactions are reviewed in detail, with emphasis on those studies that push the test of QCD and the Standard Model to the limits of their present range of validity, towards both the very high and the very low four-momentum transfers in lepton-proton scattering.

'What makes this collection unusual and refreshing is that it is not the more common ‘Festschrift’ written by specialists for specialists, but a broad set of topical summaries and analyses addressed to a wide readership of particle physicists. Inevitably, some of the sections are more advanced in their treatment than others, but most of the material will be accessible and helpful to researchers at all levels, and in particular to those working on experiments at CERN, where Altarelli spent many years in the theory group. It is hard to do justice to the varied contents of this excellent collection … I can only recommend that anyone involved in particle research should turn to the web for a full description of the richness of material that is included here … There is something here for everyone, and much for most. I’m sure Altarelli would have been pleased with that! The Editors are to be complimented for their initiative in making this unique volume possible.'Contemporary PhysicsGuido Altarelli was a leading figure in 20th century particle physics. His scientific contributions and leadership played a key role in the development of the Standard Model of fundamental interactions, as well as the current search for new physics beyond it, both at and beyond CERN. This book is a collection of original contributions, at the cutting edge of scientific research, by some of the leading theoretical and experimental high-energy physicists currently in the field. These were inspired by Guido's ideas, whether directly or indirectly. This book is ideal for researchers looking to keep up with the latest developments in high-energy physics.