Correlated pion-proton pair emission off hot and dense QCD matter

Abstract

In this letter we report the first multi-differential measurement of correlated pion-proton pairs from 2 billion Au+Au collisions at \sqrt{s_{NN}} = 2.42 GeV collected with HADES. In this energy regime the population of Δ(1232) resonances plays an important role in the way energy is distributed between intrinsic excitation energy and kinetic energy of the hadrons in the fireball. The triple differential d3N/dMπpdpTdy distributions of correlated πp pairs have been determined by subtracting the πp combinatorial background using an iterative method. The invariant-mass distributions in the Δ(1232) mass region show strong deviations from a Breit-Wigner function with vacuum width and mass. The yield of correlated pion-proton pairs exhibits a complex isospin, rapidity and transverse-momentum dependence. In the invariant mass range 1.1 < Minv (GeV/c2) < 1.4, the yield is found to be similar for π+p and π-p pairs, and to follow a power law <Apart>^α, where <Apart> is the mean number of participating nucleons. The exponent α depends strongly on the pair transverse momentum (pT) while its pT-integrated and charge-averaged value is α = 1.5 \pm 0.08stat \pm 0.2sys.

arXiv comment9 pages, 9 figures

References in corpus (45)

• Microscopic Models for Ultrarelativistic Heavy Ion Collisions
• Hadron production in central nucleus-nucleus collisions at chemical freeze-out
• Decoding the phase structure of QCD via particle production at high energy
• Comparison of Chemical Freeze-Out Criteria in Heavy-Ion Collisions
• The High-Acceptance Dielectron Spectrometer HADES
• Rho Meson Propagation and Dilepton Enhancement in Hot Hadronic Matter
• Thermal Hadron Production in High Energy Heavy Ion Collisions
• Hyperon production in Ar+KCl collisions at 1.76A GeV
• Deep sub-threshold ${\Xi }^{-}$ production in Ar+KCl reactions at 1.76A GeV
• Hadronic Spectral Functions in Nuclear Matter
• Dielectron production in Ar+KCl collisions at 1.76A GeV
• The thermal proton yield anomaly in Pb-Pb collisions at the LHC and its resolution
• Thermal Dileptons from Coarse-Grained Transport as Fireball Probes at SIS Energies
• Hadronization conditions in relativistic nuclear collisions and the QCD pseudo-critical line
• Thermodynamics of Delta resonances
• Hadronic resonance production in $d$+Au collisions at $\sqrt{s_{{}_{NN}}}$ = 200 GeV at RHIC
• Sub-threshold $\varphi$ and ${\Xi }^{-}$ production by high mass resonances with UrQMD
• Centrality determination of Au+Au collisions at 1.23A GeV with HADES
• Medium effects on pion production in heavy ion collisions
• Measurement of Pion Enhancement at Low Transverse Momentum and of the Delta-Resonance Abundance in Si-Nucleus Collisions at AGS Energy
• The N N -> N Delta cross section in nuclear matter
• Contributions of hyperon-hyperon scattering to subthreshold cascade production in heavy ion collisions
• Formation and decay of hadronic resonances in the QGP
• Abundance of Delta Resonances in 58Ni+58Ni Collisions between 1 and 2 AGeV
• Deep sub-threshold ϕ production and implications for the K+/K- freeze-out in Au+Au collisions
• Identification of baryon resonances in central heavy-ion collisions at energies between 1 and 2 AGeV
• A versatile method for simulating pp -> ppe+e- and dp -> pne+e-p_spec reactions
• Sub-threshold production of K^{0}_{s} mesons and Λ hyperons in Au(1.23A GeV)+Au
• Temperature and fluid velocity on the freeze-out surface from $\pi$, $K$, $p$ spectra in pp, p--Pb and Pb--Pb collisions
• Repulsive interactions and their effects on the thermodynamics of hadron gas
• $\Delta$(1232) Dalitz decay in proton-proton collisions at T=1.25 GeV measured with HADES
• Identical pion intensity interferometry at sqrt(s_{NN})=2.4 GeV
• Non-identical particle femtoscopy at sqrt(s_NN)=200 AGeV in hydrodynamics with statistical hadronization
• Statistical hadronization model for heavy-ion collisions in a few GeV energy regime
• Analysis of pion production data measured by HADES in proton-proton collisions at 1.25 GeV
• Delta(1232) and Nucleon Spectral Functions in Hot Hadronic Matter
• Probing chemical freeze-out criteria in relativistic nuclear collisions with coarse grained transport simulations
• Delta mass shift as a thermometer of kinetic decoupling in Au+Au reactions at 1.23 AGeV
• $\Delta$ resonances in Ca+Ca, Ni+Ni and Au+Au reactions from 1 AGeV to 2 AGeV: Consistency between yields, mass shifts and decoupling temperatures
• Forced canonical thermalization in a hadronic transport approach at high density
• High $p_T$ resonances as a possibility to explore hot and dense nuclear matter
• Resonance decay dynamics and their effects on $p_T$-spectra of pions in heavy-ion collisions
• Influence of anisotropic $\Lambda /\Sigma$ creation on the ${\Xi }^{-}$ mutiplicity in subthreshold proton-nucleus collisions
• (p,π^+-) correlations in central heavy-ion collisions at 1-2 AGeV
• An iterative method to estimate the combinatorial background

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