Low-mass e+e- pair production in 158 A GeV Pb-Au collisions at the CERN SPS, its dependence on multiplicity and transverse momentum

Abstract

We report a measurement of low-mass electron pairs observed in 158 GeV/nucleon Pb-Au collisions. The pair yield integrated over the range of invariant masses 0.2 < m < 2.0 GeV is enhanced by a factor of 3.5 +/- 0.4 (stat) +/- 0.9 (syst) over the expectation from neutral meson decays. As observed previously in S-Au collisions, the enhancement is most pronounced in the invariant-mass region 300-700 MeV. For Pb-Au we find evidence for a strong increase of the enhancement with centrality. In addition, we show that the enhancement covers a wide range in transverse momentum, but is largest at the lowest observed pt.

17 pages, 4 figures, submitted to Phys.Lett.B

References in corpus (1)

• Rho Meson Propagation and Dilepton Enhancement in Hot Hadronic Matter

Cited by in corpus (137)

• Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration
• First Measurement of the rho Spectral Function in High-Energy Nuclear Collisions
• Properties of hot and dense matter from relativistic heavy ion collisions
• Hadronic Production of Thermal Photons
• Hydrodynamic Models for Heavy Ion Collisions
• Nuclear Modification of Electron Spectra and Implications for Heavy Quark Energy Loss in Au+Au Collisions at sqrt(s_NN)=200 GeV
• Signatures of Quark-Gluon-Plasma formation in high energy heavy-ion collisions: A critical review
• Results from the Relativistic Heavy Ion Collider
• Meson vacuum phenomenology in a three-flavor linear sigma model with (axial-)vector mesons
• First observation of in-medium modifications of the omega meson
• The electrical conductivity and soft photon emissivity of the QCD plasma
• The ALICE experiment: a journey through QCD
• Measurement of single electrons and implications for charm production in Au+Au collisions at sqrt(s_NN)= 130 GeV
• Signatures of Thermal Dilepton Radiation at RHIC
• Enhanced Production of Low-Mass Electron Pairs in 40 AGeV Pb-Au Collisions at the CERN SPS
• Centrality Dependence of Charm Production from Single Electrons in Au+Au Collisions at sqrt(s_NN) = 200 GeV
• Recent results in relativistic heavy ion collisions: from ``a new state of matter'' to "the perfect fluid"
• Nucleon Resonance Transition Couplings to Vector Mesons
• e+e--pair production in Pb-Au collisions at 158 GeV per nucleon
• A Lattice Calculation of Thermal Dilepton Rates
• Phi decay in nuclei
• Excitation functions of hadronic observables from SIS to RHIC energies
• Particle Ratios, Equilibration, and the QCD Phase Boundary
• Modification of the rho meson detected by low-mass electron-positron pairs in central Pb-Au collisions at 158 A GeV/c
• Hadronic Spectral Functions in Nuclear Matter
• Thermal Dilepton Radiation at Intermediate Masses at the CERN-SpS
• Low-$p_T$ $e^{+}{e}^{-}$ pair production in Au$+$Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and U$+$U collisions at $\sqrt{s_{NN}}$ = 193 GeV at STAR
• The Chiral Restoration Transition of QCD and Low Mass Dileptons
• Properties of D-mesons in nuclear matter within a self-consistent coupled-channel approach
• Measurements of Dielectron Production in Au$+$Au Collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV from the STAR Experiment
• Mass modification of D-meson in hot hadronic matter
• Evidence for a New State of Matter: An Assessment of the Results from the CERN Lead Beam Programme
• Observation of $\rho /\omega$ Meson Modification in Nuclear Matter
• A Hadron Blind Detector for the PHENIX Experiment at RHIC
• Search for medium modification of the $\rho$ meson
• D mesons and charmonium states in asymmetric nuclear matter at finite temperatures
• Behavior of Hadrons at Finite Density -- Lattice Study of Color SU(2) QCD
• Effects of Dirac sea polarization on hadronic properties - A chiral SU(3) approach
• Recent results from Pb-Au collisions at 158 GeV/c per nucleon obtained with the CERES spectrometer
• D-mesons and charmonium states in hot isospin asymmetric strange hadronic matter
• D-mesons in asymmetric nuclear matter
• Phi-meson photoproduction from nuclei
• In-medium vector meson masses in a Chiral SU(3) model
• Quark Dispersion Relation and Dilepton Production in the Quark-Gluon Plasma
• Towards the Quark-Gluon Plasma
• The spectral function of the omega meson in nuclear matter from a coupled-channel resonance model
• The CERES/NA45 Radial Drift Time Projection Chamber
• Leptonic and charged kaon decay modes of the $\varphi$ meson measured in heavy-ion collisions at the CERN SPS
• Phases of QCD, Thermal Quasiparticles and Dilepton Radiation from a Fireball
• Production of the $\rho$(770)${}^0$ meson in pp and Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV
• Pi+ Pi- Emission in High-Energy Nuclear Collisions
• First measurement of the rho spectral function in nuclear collisions
• Indication of a Co-Existing Phase of Quarks and Hadrons in Nucleus - Nucleus Collisions
• QCD sum rule analysis for light vector and axial-vector mesons in vacuum and nuclear matter
• Sensitivity of electromagnetic spectra to equation of state and initial energy density in the Pb+Pb collisions at SPS
• Limits of Confinement: The First 15 Years of Ultra-Relativistic Heavy Ion Studies
• Near-threshold $\omega$ and $\varphi$ meson productions in $pp$ collisions
• Latest Results from CERES/NA45
• New results from CERES
• QCD sum rules for rho mesons in vacuum and in-medium, re-examined
• Measurement of low mass dielectron continuum in sqrt(s_NN)=200GeV Au+Au collisions with the PHENIX experiment at RHIC
• Duality and Chiral Restoration from Low-Mass Dileptons at the CERN-SpS
• Dilepton Radiation from Strongly Interacting Systems
• Dilepton production from hot hadronic matter in nonequilibrium
• Delta(1232) and Nucleon Spectral Functions in Hot Hadronic Matter
• Thermal Radiation from Au + Au Collisions at \sqrt{s} = 200 GEV/A Energy
• The Vector Probe in Heavy-Ion Reactions
• The omega meson at high temperatures
• Photoproduction of $\eta$-mesons off C and Cu nuclei for photon energies below 1.1 GeV
• Beam Energy Dependence of Dielectron Production in Au+Au Collisions from STAR at RHIC
• Simultaneous Softening of sigma and rho Mesons associated with Chiral Restoration
• Low Mass Dilepton Rate from the Deconfined Phase
• Photon interferometry and size of the hot zone in relativistic heavy ion collisions
• Dielectron production in proton-proton collisions at $\sqrt{s}$ = 7 TeV
• Dileptons in High-Energy Heavy-Ion Collisions
• Non-perturbative finite $T$ broadening of the $\rho$ meson and dilepton emission in heavy ion-collisions
• Hadrons in the Nuclear Medium
• In-medium vector meson properties and low-mass dilepton production from hot hadronic matter
• Heavy Scalar, Vector and Axial-Vector Mesons in Hot and Dense Nuclear Medium
• e+e- yields in Pb+Au collisions at 158 AGeV/c: Assessment of baryonic contributions
• Electromagnetic Probes
• Test of phi renormalization in nuclei through phi photoproduction
• A comprehensive description of multiple observables in heavy-ion collisions at SPS
• Density Dependent Parametrization Models: Formalism and Applications
• A Schematic Model for $\rho$-$a_1$ Mixing at Finite Density and In-Medium Effective Lagrangian
• Construction and Expected Performance of the Hadron Blind Detector for the PHENIX Experiment at RHIC
• Observing many body effects on lepton pair production from low mass enhancement and flow at RHIC and LHC energies
• Cherenkov gluons (predictions and proposals)
• The SPS Heavy Ion Programme
• Measurement of low mass dielectron continuum in sqrt(s_{NN}) = 200 GeV Au+Au collisions in the PHENIX Experiment at RHIC
• Finite temperature pion vector form factors in Chiral Perturbation Theory
• A-dependence of phi-meson production in p+A collisions
• Measuring initial temperature through photon to dilepton ratio in heavy ion collision
• Latest results from NA60
• Lepton-pair production in nuclear collisions - past, present, future
• Dilepton emission rates from hot hadronic matter
• Dimuon production from in-medium rho decays from QCD sum rules
• First results from NA60 on low mass muon pair production in In-In collisions at 158 GeV/nucleon
• Light Vector Mesons from dAu in PHENIX
• Spectral Red-Shift Versus Broadening from Photon and Dilepton Spectra
• Glueball production in hadron and nucleus collisions
• Thermal photon to dilepton ratio in ultra-relativistic heavy ion collisions
• The Quark Gluon Plasma: lattice computations put to experimental test
• Statistical Hadronization as a Snapshot of a dynamical Fireball Evolution
• Hadron Blind Cherenkov Counters
• Space-time evolution of ultra-relativistic heavy ion collisions and hadronic spectra
• Letter of Intent: the NA60+ experiment
• Absorption of $\omega$ and $\varphi$ mesons in the inclusive photonuclear reaction
• On the thermal phase structure of QCD at vanishing chemical potentials
• Relativistic Heavy-Ion Physics: Experimental Overview
• Effects of Meson Mass Reduction on the Properties of Neutron Star Matter
• Van Hove Singularities in the Quark-Gluon Plasma
• Probing dense and hot matter with low-mass dileptons and photons
• Towards the Quark Gluon Plasma
• Pion and Quark Annihilation Mechanisms of Dilepton Production in Relativistic Heavy-Ion Collisions
• Dielectron Production in Heavy Ion Collisions at 158 GeV/c per Nucleon
• Low Mass Dileptons from Pb+Au Collisions at 158 AGeV
• Pion damping width from SU(2) x SU(2) NJL model
• Hadron Masses in Medium and Neutron Star Properties
• The Delta(1232) at RHIC
• Quark-Gluon Plasma: Status of Heavy Ion Physics
• Charm and leptons
• Effective mass and decay of ${\Theta }^{+}$ in nuclear matter in quark-meson coupling model
• $\rho$ - meson spectral function in hot nuclear matter
• Dielectron production in Au$+$Au collisions at $\sqrt{s_{NN}}$=200 GeV
• Shadowing in photo-production : role of in-medium hadrons
• Measurements of the electron-positron continuum in ALICE
• Current Status of Quark Gluon Plasma Signals
• Role of in-medium hadrons in photon-nucleus reactions : shadowing and dilepton spectrum
• A global description of heavy-ion collisions
• Dilepton production from hydrodynamically expanding fireball
• Heavy-ion physics at the CERN SPS H2: NA35, NA49 and NA61/SHINE (with personal recollections)
• Study of in-medium $\omega$ meson properties in Ap, pA and AA collisions
• Spin as an additional tool for QGP investigations
• Electromagnetic Radiation and in-Medium Effects
• Coherent QED, Giant Resonances and $(e^{+}{e}^{-})$ Pairs in High Energy Nucleus-Nucleus Collisions
• Searching for P- and CP-odd effects in heavy ion collisions