Di-lepton spectroscopy in CBM

Abstract

The compressed baryonic matter (CBM) experiment at the future FAIR facility near Darmstadt, Germany, will investigate baryonic matter at highest net-baryon densities but moderate temperatures by colliding nuclei at beam energies from 10 to 45 A GeV. Among the key observables are low-mass vector mesons and charmonium decaying into lepton pairs as they leave the hot and dense fireball without further interactions, thus providing undisturbed information from this early dense phase of the collision. In this paper, investigations for both decay channels, di-electrons and di-muons are presented in terms of detector concepts, simulations and feasibility studies.

Influence of the hadronic phase on observables in ultrarelativistic heavy ion collisions

“…Present and future [2] experiments aim at a better understanding of the properties of the QGP (see e.g. [7,8]).…”

The Compressed Baryonic Matter Experiment at FAIR

“…The combined electron identification efficiency of RICH and TRD is 85% at a pion suppression factor of 10 4 . The remaining background is dominated by π 0 Dalitz decays [8]. Muon identification is performed with a segmented hadron absorber and a 03001-p.2 tracking system downstream of the STS.…”

“…After another 1 m of iron and total 13.5 nuclear interaction lengths, the J/ψ pair candidates are detected. The particle multiplicity is reduced such that after 1.25 m iron 0.25 identified muons are obtained in 25A GeV Au+Au with the dominant background coming from π and K decays at 0.13 muons per event [8]. Spectra and phase-space coverage of reconstructed di-leptons are shown in Figs.…”

J/ψ reconstruction in the di-muon decay channel with the CBM experiment for p+Au collisions at 30 GeV laboratory beam energy

“…In order to provide continuous tracking, a TRD (Transition Radiation Detector) is installed after MuCh. A TOF (Time of Flight) wall completes the setup [3] 3. Feasibility studies In order to study the feasibility of charmonium reconstruction in the di-muon channel simulations were performed for p+Au collision at 30 GeV laboratory beam energy within the simulation framework CBMROOT [4], which allows full event simulation and reconstruction.…”