Related papers: Dilepton production and off-shell transport dynami…
We compare different formalisms for the calculation of lepton pair emission in hadron-hadron collisions and discuss the consequences of the approximations inherent to each of them. Using a Lorentz-covariant and gauge-invariant formalism…
The dilepton invariant mass spectrum measured in heavy-ion collisions includes contributions from important QGP probes such as thermal radiation and the quarkonium ($J/\psi$, $\psi'$ and $\Upsilon$) states. Dileptons coming from hard $q…
The tagged quasi-free $np \to np\pi^+\pi^-$ reaction has been studied experimentally with the High Acceptance Di-Electron Spectrometer (HADES) at GSI at a deuteron incident beam energy of 1.25 GeV/nucleon ($\sqrt s \sim$ 2.42 GeV/c for the…
The production of $\eta'$ mesons in the reactions $pp\to pp\eta'$ and $pn\to pn\eta' $ at threshold-near energies is analyzed within a covariant effective meson-nucleon theory. The description of cross section and angular distributions of…
Through the analysis of HELIOS-3 data obtained at the CERN SPS, we demonstrate the importance of secondary processes for dilepton production in heavy-ion collisions in the intermediate invariant mass region. We find that while the dilepton…
Nucleon flow in Au+Au collisions at 1 GeV/nucleon region and dilepton spectra in S+Au collisions at SPS energies are analysed in the relativistic transport model. They are shown to be sensitive to the nucleon vector and scalar potentials,…
Results on $\Lambda$ hyperon production are reported for collisions of p(3.5 GeV) + Nb, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18 at GSI Helmholtzzentrum for Heavy-Ion Research, Darmstadt. The transverse…
The transport of hadrons with dynamical spectral functions A_h(X,\vec{P},M^2) is studied for nucleus-nucleus collisions at SIS and AGS energies in comparison to the conventional quasi-particle limit and the available experimental data…
We present a model of electron-positron pair production in pion-nucleon collisions in the exclusive reaction \pi N -> Ne^+e^-. The model is based on an effective field theory approach, incorporating 16 baryon resonances below 2 GeV.…
We present dilepton spectra from p+p and p+Nb collisions at a kinetic beam energy of 3.5 GeV, which were simulated with the GiBUU transport model assuming different in-medium scenarios. We compare these spectra to preliminary HADES data and…
We present the results of a study of charged pion production in 12C + 12C collisions at incident beam energies of 1A GeV and 2A GeV using the HADES spectrometer at GSI. The main emphasis of the HADES program is on the dielectron signal from…
The HADES collaboration has extracted dilepton mass spectra for $\pi^-$ induced reactions on the proton from a comparison of data taken on C and CH$_2$ targets. The spectra were interpreted in terms of different versions of vector meson…
The production of dileptons with an invariant mass in the range 1 GeV < M < 5 GeV provides unique insight into the approach to thermal equilibrium in ultrarelativistic nucleus-nucleus collisions. In this mass range, they are produced…
A low-background inclusive search for new physics in events with same-sign dileptons is presented. The search uses proton-proton collisions corresponding to 20.3 fb$^{-1}$ of integrated luminosity taken in 2012 at a centre-of-mass energy of…
Dilepton spectra from the decay of phi mesons produced in heavy-ion collisions at SIS/GSI energies ($\sim 2$ GeV/nucleon) are studied in the relativistic transport model. We include phi mesons produced from baryon-baryon, pion-baryon, and…
Events containing a pair of charged leptons and significant missing transverse momentum are selected from a data sample corresponding to a total integrated luminosity of 20.6 pb^-1 at centre-of-mass energies of 161 GeV and 172 GeV. The…
The production and decay of vector mesons ($\rho, \omega$) in $pA$ reactions at COSY energies is studied with particular emphasis on their in-medium spectral functions. It is explored within transport calculations, if hadronic in-medium…
We present the inclusive invariant-mass, transverse momentum and rapidity distributions of dielectrons (e$^{+}$e$^{-}$ pairs) in p+p interactions at 3.5 GeV beam kinetic energy. In the vector-meson mass region, a distinct peak corresponding…
The production yield and angular anisotropy of prompt ${D_s^+}$ mesons were measured as a function of transverse momentum ($p_{ T}$) in Pb-Pb collisions at a centre-of-mass energy per nucleon pair $\sqrt{s_{ NN}} = 5.02$ TeV collected with…
The production of soft dileptons in a thermal mesonic medium is discussed in the context of recent CERN experimental data reported by the CERES Collaboration. We do not intend to give a general and critical review, but instead concentrate…