Related papers: New QCD results from LEP
Recent results on measurements of the strong coupling $\alpha_S$ from LEP are reported. These include analyses of the 4-jet rate using the Durham or Cambridge algorithm, of hadronic $Z^0$ decays with hard final state photon radiation, of…
A search for new phenomena is performed in final states containing one or more jets and an imbalance in transverse momentum in pp collisions at a centre-of-mass energy of 13 TeV. The analysed data sample, recorded with the CMS detector at…
A search for anomalous production of events with three or more isolated leptons and bottom-quark jets produced in pp collisions at sqrt(s) = 8 TeV is presented. The analysis is based on a data sample corresponding to an integrated…
Measurements of hadronic final state interactions in W-pair events at LEP are presented. In particular, different scenarios of colour reconnection are studied. The data agree with moderate colour reconnection effects. Extreme scenarios are…
Hadronic jets are extremely abundant at the LHC, and testing QCD in various corners of phase-space is important to understand backgrounds and some specific signatures of new physics. In this article, various measurements aiming at probing…
We present results from several searches for various exotic physics phenomena like large extra dimensions, leptoquarks, and dark matter, in proton-proton collisions at $\sqrt{s}$ = 7 and 8 TeV delivered by the LHC and collected with the CMS…
The perturbative QCD approach to multiparticle production predicts a characteristic suppression of particle multiplicity in a heavy quark jet as compared to a light quark jet. In the Modified Leading Logarithmic Approximation (MLLA) the…
We compared the multiplicities of pizero, eta, Kzero and of charged particles in quark and gluon jets in 3-jet events, as measured by the OPAL experiment at LEP. The comparisons were performed for distributions unfolded to 100% pure quark…
Results are reported from a search for supersymmetric particles in the final state with multiple jets and large missing transverse momentum. The search uses a sample of proton-proton collisions at $\sqrt{s} =$ 13 TeV collected with the CMS…
W+jets, Z+jets and QCD multijet production processes at hadron colliders are backgrounds to many searches for physics beyond the Standard Model which involve leptons and missing energy in the final state. We review the current theoretical…
Three of the most significant measured deviations from standard model predictions, the enhanced decay rate for B $\to$ D$^{(*)}\tau\nu$, hints of lepton universality violation in B $\to$ K$^{(*)}\ell\ell$ decays, and the anomalous magnetic…
We consider the production of jets in photon-photon collisions beyond the leading logarithm approximation. Theoretical uncertainties as well as uncertainties due to the virtuality of the initial photons are discussed in detail. The…
Aspects of ICHEP 2004 are summarized from a theoretical point of view. QCD works, new NNLO calculations are becoming available and new string calculational tools are emerging, but no conclusions can yet be drawn about the discovery of the…
We present a theoretical review of the possibilities offered by heavy flavour tagging in testing QCD features in 4-jet events at LEP1. Attention is focused mainly on the properties of the angular variables which are used in the experimental…
The ALICE experiment at LHC is dedicated to study matter formed in heavy-ion collisions, but also has a strong physics program for $pp$ collisions. In these collisions, protons will collide at energies never reached before under laboratory…
This paper presents a search for a new heavy particle produced in association with a top or antitop quark. Two models in which the new heavy particle is a color singlet or a color triplet are considered, decaying respectively to tbarq or…
Having pure samples of quark and gluon jets would greatly facilitate the study of jet properties and substructure, with many potential standard model and new physics applications. To this end, we consider multijet and jets+X samples, to…
We summarize measurements of b and c jet production at the LHC, which are an important signature and background for decays of massive particles such as H-to-b-bbar. These include measurements of the inclusive and dijet production of heavy…
The light gluino hypothesis can explain the apparent incompatibility between the measurements of $\as$ at low- and high-energy. Such gluinos are produced directlyin four-jet events, for which we perform a detailed analysis. Because the jet…
We present a unified overview of recent progress in the study of QCD radiation in heavy-quark jets, focusing on the dead-cone effect. Using precision data from LEP at $\sqrt{s}=91.2$~GeV, we demonstrate strong momentum-space suppression in…