Related papers: Higher order QED in high mass e+ e- pairs producti…
Electron pairs or di-leptons in general are unique probes to study the hot and dense matter formed in relativistic heavy ion collisions at RHIC. Particularly, low mass di-leptons are sensitive to chiral symmetry restoration effects and to…
We employ data taken by the JADE and OPAL experiments for an integrated QCD study in hadronic e+e- annihilations at c.m.s. energies ranging from 35 GeV through 189 GeV. The study is based on jet-multiplicity related observables. The…
Most recent PHENIX results on electromagnetic probes are presented including first preliminary results obtained with the Hadron Blind Detector (HBD) on e+e- invariant mass spectra from Au+Au collisions at sqrt(s_NN) = 200 GeV.
The J/$\psi$ yields in heavy ion collisions are expected to be a promising probe of deconfined matter, since theoretical models predict that the J/$\psi$ production could be strongly suppressed due to color screening effect in a Quark Gluon…
Results from the PHENIX experiment at RHIC on direct photon production in p+p, d+Au, and Au+Au collisions at sqrt(s_NN) = 200 GeV are presented. In p+p collisions, direct photon production at high p_T behaves as expected from perturbative…
Measurements of two particle azimuthal correlations in relativistic heavy ion collisions provide information of the possible interplay between hard-scattered partons and the hot-dense medium. Toward an understanding of parton-medium…
RHIC-PHENIX has observed a large suppression pattern and azimuthal anisotropy of non-photonic electron at mid-rapidity ($\mid\eta\mid<0.35$) in Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV. To understand these results and the interaction…
We present a complete next-to-leading order study of top-squark pair production at the LHC, including QCD and EW corrections. The calculation is performed within the Minimal Supersymmetric Standard Model and numerical results are presented…
Recent Results from the PHENIX Collaboration on Au+Au and d+Au collisions at the Relativistic Heavy Ion Collider.
Recently, significant enhancements of $e^{+} e^{-}$ pair production at very low transverse momentum ($p_{T} < 0.15$ GeV/c) were observed by the STAR collaboration in peripheral hadronic A+A collisions. This excesses can not be described by…
The PHENIX Experiment at RHIC has conducted a beam energy scan at several collision energies in order to search for signatures of the QCD critical point and the onset of deconfinement. PHENIX has conducted measurements of transverse energy…
We calculate first-order QCD corrections to the cross section for single top quark production mediated by flavor changing neutral currents (FCNC) in ep collisions at the HERA collider. We find that the uncertainty due to the choice of the…
There is significant interest in RHIC heavy ion collisions at $\sqrt{s_{NN}}=$5--50 GeV, motivated by a search for the QCD phase transition critical point. The lowest energies for this search are well below the nominal RHIC gold injection…
Four-fermion processes with a particle lost in the beam pipe are studied at LEP to perform precision tests of the electroweak theory. Leading higher-order QED corrections to such processes are analyzed within the framework of the Structure…
The preceding experimental and theoretical results on the rare decay $\pi^0 \to e^+e^-$ are briefly summarized. Already computed two-loop QED corrections are reviewed and the bremsstrahlung contribution beyond the soft-photon approximation…
Hadron production in leading order pQCD is reviewed. The shape of the single inclusive particle spectra is well described for $p_T \geq 2-3$ GeV at center of mass energies from 20 GeV to 2 TeV. The phenomenological K-factor is found to…
We present a detailed description of our calculation of next-to-leading order QCD corrections to heavy quark production in e^+ e^- collisions including mass effects. In particular, we study the observables $R_3^{b\ql}$ and $D_2^{b\ql}$ in…
Top quark production in electron-positron annihilation is one of the benchmark reactions at a future linear collider. Both electroweak and QCD corrections are large, amounting to 10% or even more in specific kinematic regions. In this note…
We use the available data on e+ e- -> hadrons to determine the value of the QED coupling at the Z pole. The inclusion of recent preliminary BES-II data in the analysis is found to reduce the ambiguity in the determination of the coupling,…
Measurements of hadronic final states in $e^{+}e^{-}$ collisions at centre-of-mass (CM) energies below the Z peak can notably extend the FCC-ee physics reach in terms of precision quantum chromodynamics (QCD) studies. Hadronic final states…