Related papers: Recent Theoretical Developments in LEP 2 Physics
The properties of hard photon radiation in $W$ pair production at LEP 2 are studied, with emphasis on the energy loss relevant to the W mass measurement. We use a combination of the exact 1-photon matrix element and leading logarithmic…
Recent results on hadron multiplicities in heavy and light quark fragmentation above the Z peak (OPAL), and multiplicity distribution analysis (L3) and inclusive f_1 production (DELPHI) in hadronic Z decays are presented.
Recent theoretical scenarios propose that quantum gravity effects may manifest at LEP energies by means of gravitons that couple to Standard Model particles and propagate into extra space dimensions. These predictions are checked against…
Electroweak measurements performed with data taken at the electron-positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3 fb$^{-1}$…
Numerous searches for new phenomena have been carried out using data from proton-antiproton collisions at Fermilab's Tevatron. Final states with leptons give signatures which are relatively unique and generally have small backgrounds. We…
We consider the Schwinger production of baryons in an external electric field in the worldline instanton approach. The process occurs in the confinement regime hence the holographic QCD and the Chiral Lagrangian are used as the tools. The…
We investigate the weak interaction emission of spin-1/2 fermions from accelerated currents. As particular applications, we analyze the decay of uniformly accelerated protons and neutrons, and the neutrino-antineutrino emission from…
We report the most restrictive direct limits on masses of fourth-generation down-type quarks $b^{\prime}$, and quark-like composite fermions ($B$ or $T_{5/3}$), decaying promptly to $t W^{\mp}$. We search for a significant excess of events…
We analytically calculate the total and differential cross sections for the pair production of doubly heavy baryons in the framework of diquark model. The processes of electron-positron and quark-antiquark annihilations are considered. The…
Some general considerations on a future linear collider and selected topics of two photon physics measurements which can be performed at such a collider are presented. This review discusses the total photon-photon cross section, jet cross…
We report recently published results on central exclusive production of di-jets and di-photons, and exclusive QED production of e+e- pairs. In addition, we discuss preliminary results on exclusive photoproduction of charmonium and…
Numerical results on non-factorizable corrections to e+e- --> WW --> 4fermions with semi-leptonic and hadronic final states, as well as to e+e- --> ZZ --> 4fermions, are presented. The corrections turn out to be small in comparison to the…
We present a theoretical study of a double lepton pair production in ultra--relativistic collision between two bare ions. Special emphasis is placed to processes in which creation of (at least one) $e^+ e^-$ pair is accompanied by the…
Supersymmetry, if realized in Nature, predicts the existence of new particles, as chargino and neutralino, which might manifest themselves with peculiar signatures. Three leptons and large missing transverse energy in the event could signal…
Cross sections, angular distributions and forward-backward asymmetries are presented, of two-fermion events produced in e+e- collisions at centre-of-mass energies from 189 to 209 GeV at LEP, measured with the ALEPH detector. Results for…
We briefly describe the RacoonWW approach to calculate radiative corrections to e+ e- -> W W -> 4 fermions and present numerical results for the total W-pair production cross section at LEP2.
We derive limits on a class of new physics effects that are naturally present in grand unified theories based on extended gauge groups, and in particular in $E_6$ and $SO(10)$ models. We concentrate on $i$) the effects of the mixing of new…
An analysis of the data collected in 1997 and 1998 with the DELPHI detector at e+e- collision energies close to 183 and 189 GeV was performed in order to extract the hadronic and leptonic fermion-pair cross-sections, as well as the leptonic…
We present an analysis of ZZ production at the upgraded Fermilab Tevatron for general ZZZ and ZZ-gamma couplings. Achievable limits on these couplings are shown to be a significant improvement over the limits currently obtained by LEP II.
We discuss three promising diagnostic probes of the couplings of a possible heavy $Z'$ boson at hadron colliders: the forward-backward asymmetry into leptons, the rare decay $Z' \ra W^{\pm} \ell^{\mp} \nu$, and associated production $pp \ra…