Related papers: Colour Reconnection at LEP
We consider whether a discrepancy between the SLAC and LEP measurements of $\Sw$ can be explained by new physics. We find that only the contribution of a new neutral gauge boson, $Z^\prime$, nearly degenerate with the Z can affect the SLAC…
We present a metric on the space of scattering events based on relative transverse momenta and with explicit sensitivity to intermediate resonances. With this new metric, negative weights in an event sample can be reduced substantially…
A study of color coherence effects in pp collisions at a center-of-mass energy of 7 TeV is presented. The data used in the analysis were collected in 2010 with the CMS detector at the LHC and correspond to an integrated luminosity of 36…
Two topics on the standard electroweak theory are discussed based on its remarkable success in precision analyses. One is a test of structure of the radiative corrections to the weak-boson masses as a further precision analysis. The other…
We present a study of the LHC sensitivity to the W boson mass based on simulation studies. We find that both experimental and phenomenological sources of systematic uncertainties can be strongly constrained with Z measurements: the…
Two-photon collisions at the e$^+$e$^-$ colliders allow to investigate the formation and the properties of resonant states in a very clean experimental environment. A remarkable number of new results have been recently obtained giving…
At present and future hadron colliders, the precision physics program started in the past will be continued. In particular, a precise determination of the W boson mass will be carried out. This requires the calculation of the radiative…
This note presents a combination of published and preliminary electroweak results from the four LEP collaborations and the SLD collaboration which were prepared for the 2003 summer conferences. Averages from $\Zzero$ resonance results are…
Colour coherence in hard photoproduction is considered using the Monte Carlo event generators PYTHIA and HERWIG. Significant effects in the parton shower are found using multijet observables for direct and resolved photon induced reactions.…
The mass and width of the W boson are determined in e+e- collisions at LEP using 183 pb^-1 of data recorded at a centre-of-mass energy roots=189 GeV with the OPAL detector. The invariant mass distributions from 970 WW->qqqq and 1118…
Radiative Corrections to $W$ Pair Production and effects of finite width of the $W$ bosons are studied using the Monte Carlo {\tt WOPPER}. As an example the influence of QED radiative corrections on the reconstruction of the $W$ helicities…
Deep inelastic electron-photon scattering is studied in the Q**2 range from 1.2 to 30 GeV**2 using the LEP1 data taken with the ALEPH, L3 and OPAL detectors at centre-of-mass energies close to the mass of the Z boson. Distributions of the…
We point out that the so--called 'radiative return' events at LEP2 are suited to the study of nonstandard physics, particularly if the vector bosons are emitted into the central detector region. An effective vertex is constructed which…
We describe the implementation details of the colour reconnection model in the event generator Herwig++. We study the impact on final-state observables in detail and confirm the model idea from colour preconfinement on the basis of studies…
The color memory effect is the non-abelian gauge theory analog of the gravitational memory effect, in which the passage of color radiation induces a net relative SU(3) color rotation of a pair of nearby quarks. It is proposed that this…
A measurement of the mass of the $W$ boson is presented based on proton-proton collision data recorded in 2011 at a centre-of-mass energy of 7 TeV with the ATLAS detector at the LHC, and corresponding to 4.6 fb$^{-1}$ of integrated…
We report the results of a study of color coherence effects in ppbar collisions based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron Collider, at a center of mass energy sqrt(s) = 1.8 TeV.…
Electroweak precision observables allow stringent tests of the Standard Model at the quantum level and imply interesting bounds on the mass of the Higgs boson through higher-order loop effects. Very significant constraints come especially…
We investigate production of $J/\psi$ mesons in hadron-hadron collisions, defined as low invariant mass $c\bar{c}$ singlets produced in a mixture of perturbative and nonperturbative mechanisms provided by the PYTHIA Monte Carlo. We find…
The simple "straw-man" model of low-scale technicolor contains light color--singlet technihadrons, which mix with the electroweak gauge bosons. We present lepton collider production rates at the parton level, and show that experiments at…