This writeup summarizes the main experimental studies of the strong interaction, theoretically described by quantum chromodynamics (QCD), that were presented during the ICHEP-2020 conference. The latest results, measured mostly in p-p collisions at the LHC, are categorized in seven broad topics: (i) Extractions of the strong coupling constant $α_s(m_{\rm Z})$; (ii) Comparison of data to fixed-order (N$^{\rm n}$LO) perturbative QCD calculations; (iii) Determinations of parton distribution functions (PDFs); (iv) Comparison of data to resummed (N$^{\rm n}$LL) pQCD calculations; (v) Parton showering and jet substructure analyses; (vi) Semihard (double parton interactions, multiparton interactions, hard diffraction), and soft (elastic and diffractive) QCD scatterings; and (vii) Studies of parton hadronization in $\rm e^+e^-$ and p-p collisions.
A brief overview of the main highlights discussed at ICHEP 2014 is presented. The experimental data confirm that the scalar boson discovered at the LHC couples to other particles as predicted in the Standard Model. This constitutes a great success of the present theoretical paradigm, which has been confirmed as the correct description at the electroweak scale. At the same time, the negative searches for signals of new phenomena tightly constrain many new-physics scenarios, challenging previous theoretical wisdom and opening new perspectives in fundamental physics. Fresh ideas are needed to fac…
Summary talk at ICHEP 2002, Amsterdam, July 2002. I have kept very close to the content and style of the talk as it was delivered. You may access the associated PowerPoint presentation through a link at http://www.ichep02.nl/MainPages/PlenaryProgram.html
The conference included about 90 talks covering a plethora of different sectors, like Higgs physics, electroweak physics, top physics, BSM physics, soft QCD, jets, PDFs, heavy ions, heavy flavours, spectroscopy, etc. A few experimental results are here highlighted.
The Les Houches Workshop on Physics at TeV Colliders took place from June 8-18, 1999. One of the three working groups at Les Houches concentrated on QCD issues, both at the Tevatron Collider and at the LHC. Besides the interest in QCD in its own right, QCD dynamics plays an important role in the production mechanisms for any new physics process that might be observed at either collider, as well as any processes that may form backgrounds to the new physics. This writeup serves both as a pedagogical overview of QCD as well as an update on the current status of the field.
Highlights of the experimental results presented at the 39th Rencontres du Moriond on ``QCD and High Energy Hadronic Interactions'', which was held in La Thuile, Italy on Mar. 28 - Apr. 4, 2004 are briefly summarised.
2008 was a vintage year for the QCD Moriond meeting. Plenty of new data from Tevatron, HERA, B-Factories and other experiments have been reported. Some brand new results became public just before or even during the conference. A few new hints for New Physics came up in Winter 2008, but these await further scrutiny. This paper is the write-up of the experimental summary talk given at the Moriond QCD March meeting.
This paper attempts to summarise the highlights of the talks presented in Parallel Session II of the SPIN 2004 Symposium dedicated to the QCD spin structure of nucleons. Emphasis is put on new data and theoretical developments.
Recent results on jet physics and tests of QCD from hadronic final states in $e^+e^-$ annihilation at PETRA and at LEP are reviewed, with special emphasis on hadronic event shapes, charged particle production rates, properties of quark and gluon jets and determinations of $α_s$. The data in the entire energy range from PETRA to LEP-2 are in broad agreement with the QCD predictions. The world summary of measurements of $α_s$ is updated and a detailed discussion of various methods to determine the overall error of $α_s (M_Z)$ is presented. The new world average is $α_s (M_Z) = 0.119 \pm 0.004$. …
The article presents experimental highlights of Moriond 2013 QCD conference. This was fantastic conference and the first Moriond QCD since the discovery of the Higgs boson. Many new results about its properties have been presented at the conference with Higgs-like particle becoming a Higgs as it properties match expected for the Higgs boson pretty well. There were many new results presented in all experimental areas including QCD, elecroweak, studies of the top, bottom and charm quarks, searches for physics beyond Standard Model as well as studies of the heavy ion collisions. 56 experimental t…
A brief summary of recent measurements of QCD jet production at the LHC, featuring results from ATLAS and CMS, is given. Results for heavy flavours are also shown.
The Moriond conference on QCD and High Energy Interactions has been a most exciting and interesting event once more. This year's edition has been characterized by a very large amount of new results from the LHC experiments. However, also the experiments at other present or past accelerators are still giving extremely important input to our quest for the understanding of nature at shortest distance scales. In this review I will attempt to summarize the main experimental highlights of this conference.
This short summary reviews the recent progress in the computation of higher-order corrections to W+b W-antib production. In addition, new phenomenological studies reveal potential problems that may affect precision measurements at the LHC.
We present a summary of the first calculation of NLO QCD corrections to WZjj production with leptonic decays at the LHC. Our results show that the next-to-leading order corrections reduce significantly the scale uncertainties.
I discuss new experimental results reported at this conference that bear directly on three previously reported anomalies: the excess of high Q^2 events at HERA; the excess of W + 1 jet events, relative to W's without jets, in D0 data; and the excess of high E_T inclusive jets observed by CDF. The new results all point in the direction of reducing the experimental significance of these excesses.
Determinations of the strong coupling strength, $α_s$, are summarised and a new world average value of $α_s (M_Z)$ is determined, using a new method of pre-averaging results within classes of measurements like hadronic $τ$ decays, deep inelastic scattering processes, lattice calculations, electron-positron annihilation processes and electro-weak precision fits. The overall result is $$α_s (M_Z) = 0.1184 \pm 0.0007,$$ unchanged from the value obtained in 2009. This presentation is an excerpt from the QCD review section of the 2012 Review of Particle Physics (RPP) of the Particle Data Group.
We present a summary of the Hadronic Final States parallel sessions of the DIS99 Workshop. Topics were presented over two days and included both theoretical and experimental talks. Recent progress in the understanding of QCD in deep inelastic scattering, e^+e^- collisions, and in gamma and p collisions was discussed.
We summarize recent results obtained in [1] on the running m_{c,b}(m_{c,b}) in the MS scheme and f_{D_(s), B_(s)} using QCD spectral sum rules (QSSR) known to N2LO PT series, including all dimension-six NP condensate contributions in the full QCD theory, an estimate of the N3LO terms based on the geomteric growth of the PT series and using the most recent values of the QCD input parameters given in Table [1]. The study of the effects of the subtraction scale μon "different QSSR data" and the use (for the first time) of the Renormalization Group Invariant (RGI) scale independent quark masses in…
A summary is given of some important developments in QCD studies of the nucleon as presented at this workshop. Based on these developments some expectations for the short- and long-term future of the field are sketched. Taken together, the summary of the workshop and the future perspectives result in a {\sl Road Map} for experimental studies of the QCD structure of the nucleon. The Road Map includes as a long-term goal the construction of new lepton-hadron scattering facilities both in Europe and the United States.
Recent experimental results on color coherence phenomena from e+e-, ep, and ppbar collisions are presented. The data are compared to analytic perturbative QCD calculations based on the modified leading logarithm approximation and the local parton hadron duality hypothesis.
A summary of QCD results obtained at e+e- experiments in recent years is given. Emphasis is put on basic QCD tests and α_s measurements with event shapes.
Recent highlights from the HERA experiments, Hermes, H1 and ZEUS, are reviewed and ideas for future analyses to fully exploit this unique data set are proposed. This document is a summary of a workshop on future physics with HERA data held at DESY, Hamburg at the end of 2014. All areas of HERA physics are covered and contributions from both experimentalists and theorists are included. The document outlines areas where HERA physics can still make a significant contribution, principally in a deeper understanding of QCD, and its relevance to other facilities. Within the framework of the Data Pres…
A summary of the measurements of the QCD colour factors at LEP is presented. Such measurements provide a test of the gauge group structure underlying the theory of strong interactions. A variety of methods have been applied by the various experiments, and perfect consistency with the expectation of QCD with SU(3) as gauge group is found.
Recent results on QCD studies in e+e- annihilations at LEP are presented. Data recorded by the LEP experiments at centre-of-mass energies between 91.2 to 206 GeV are included. The main topic is the measurement of alpha_s from event-shape variables and associated aspects like the energy evolution or non-perturbative power-law corrections. These 'standard' measurements are complemented by new determinations using the 4-jet rate with an excellent precision. A summary of the results on QCD colour factors from angular correlations in the 4-jet system completes this report.
Four years after the shutdown of the Tevatron proton-antiproton collider, the two Tevatron experiments, CDF and DZero, continue producing important results that test the theory of the strong interaction, Quantum Chromodynamics (QCD). The experiments exploit the advantages of the data sample acquired during the Tevatron Run II, stemming from the unique pp initial state, the clean environment at the relatively low Tevatron instantaneous luminosities, and the good understanding of the data sample after many years of calibrations and optimizations. A summary of results using the full integrated lu…
A summary is given of some recent QCD results from LEP. For LEP-2, the topics include event shape measurements, determinations of the strong coupling constant, and measurements of the charged particle multiplicity distribution at the recently completed run at 189 GeV. For LEP-1, the topics presented are a test of the flavor independence of the strong coupling constant and a study of gluon jets using a hemisphere definition to correspond to analytic calculations. For the combined LEP data samples, the topics include a test of power law corrections for hadronization effects and the running of th…
Quantum Chromodynamics (QCD), the gauge field theory of the Strong Interaction, has specific features, asymptotic freedom and confinement, which determine the behaviour of quarks and gluons in particle reactions at high and at low energy scales. QCD predicts that the strong coupling strength $\as$ decreases with increasing energy or momentum transfer, and vanishes at asymptotically high energies. In this review, the history and the status of experimental tests of asymptotic freedom are summarised. The world summary of measurements of $\as$ is updated, leading to an unambiguous verification of …
We present a summary of the physics of gluon saturation and non-linear QCD evolution at small values of parton momentum fraction $x$ in the proton and nucleus in the context of recent experimental results at HERA and RHIC. The rich physics potential of low-x studies at the LHC, especially in the forward region, is discussed and some benchmark measurements in pp, pA and AA collisions are introduced.
We present a summary of results from studies of quantum chromodynamics at the Fermilab Tevatron collider by the CDF and the D0 experiments. These include Run II results for the time period up to the end of Summer 2014. A brief description of Run I resultsis also given. This review covers a wide spectrum of topics, and includes measurements with jet and vector boson final states in the hard (perturbative) energy regime, as well as studies of soft physics such as diffractive and elastic scatterings, underlying and minimum bias events, hadron fragmentation, and multiple parton interactions.
This report is the summary of the Eighth International Conference on Quarks and Nuclear Physics (QNP2018). Hadron and nuclear physics is the field to investigate high-density quantum many-body systems bound by strong interactions. It is intended to clarify matter generation of universe and properties of quark-hadron many-body systems. The QNP is an international conference which covers a wide range of hadron and nuclear physics, including quark and gluon structure of hadrons, hadron spectroscopy, hadron interactions and nuclear structure, hot and cold dense matter, and experimental facilities.…
In this work we present a summary of the most relevant results on heavy-ion and astroparticle physics in ALICE. The summary includes a brief overview of the current status on the characterization of the hot and dense QCD medium created in the heavy-ion collisions produced at the LHC, as well as the intriguing finding of collective-like phenomena in small collision systems.
