Dilepton production in ultrarelativistic heavy-ion collisions

Koch, Volker; Song, Chungsik

doi:10.1103/physrevc.54.1903

Cited by 52 publications

(51 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Ref. [36] the cross section approach based on Eq. (4.76) has been employed by simply multiplying σ π + π − →e + e − (M ) with a temperature-dependent 'in-medium correction factor', which is determined as the ratio…”

Section: Transport Simulationsmentioning

confidence: 99%

“…The left panel shows recent BUU transport calculations [257] along the lines of Ref. [36] where the in-medium effects entirely reside in finite temperature effects in the ππ annihilation channel and πρ-type contributions (dominated by the a 1 (1260)). Due to collisional broadening introduced in the (denominator of) the pion electromag- netic form factor the significance of the in-medium ππ channel is rather moderate; the processes inducing the broadening (i.e., πρ collisions) are treated explicitely for dilepton production to approximately restore unitarity in the transport framework.…”

Section: Agev Lead Beam Runsmentioning

confidence: 99%

See 1 more Smart Citation

Chiral Symmetry Restoration and Dileptons in Relativistic Heavy-Ion Collisions

Rapp

Wambach

2002

Advances in Nuclear Physics

545

258

View full text Add to dashboard Cite

The current theoretical status in the analysis and interpretation of low-mass dilepton measurements in (ultra-) relativistic heavy-ion experiments is reviewed. Special emphasis is put on potential signals of (partial) restoration of dynamically broken chiral symmetry in a hot and dense hadronic medium. It follows from chiral symmetry alone that parity partners of hadronic correlation functions must become identical when the symmetry is restored. The assessment of medium effects in the vector channel, which governs the dilepton production, thus necessitates a simultaneous treatment of the vector and axialvector degrees of freedom. While significant progress in this respect has been made some open questions remain in establishing a rigorous link in the mass region below 1 GeV. From the present calculations a suggestive 'quark-hadron duality' emerges near the phase boundary. It implies substantial medium effects in the dilepton signal from the hadronic phase which smoothly matches a perturbative description within the plasma phase.

show abstract

Section: Transport Simulationsmentioning

confidence: 99%

Section: Agev Lead Beam Runsmentioning

confidence: 99%

Chiral Symmetry Restoration and Dileptons in Relativistic Heavy-Ion Collisions

Rapp

Wambach

2002

Advances in Nuclear Physics

545

258

View full text Add to dashboard Cite

show abstract

“…In this context, the properties of vector mesons (especially of the ρ) in a hadronic environment become of particular interest, since the Vector Meson Dominance Model is commonly used to make the estimates of the dilepton yields from vector-meson decays. There are numerous analysis of the effect in the literature, both in hydrodynamic approaches [42,70,71,72,73], and in transport theories [13,74,75,76,77,78,79,80]. The dilepton-rate formula [81,82,83,84,85] from ρ meson decays can be written in a manifestly Lorentz covariant way as follows:…”

Section: Dilepton Production Ratementioning

confidence: 99%

ρ→ππ decay in nuclear medium

2001

View full text Add to dashboard Cite

We calculate the medium modifications of the ρππ vertex in a relativistic hadronic framework incorporating nucleons and ∆(1232) isobars, and find a substantial increase of the ρππ coupling, dominated by processes where the ∆ is excited. The coupling depends significantly on the virtuality of the ρ, which is related to analytic properties of the vertex function. We analyze the general case of a non-zero three-momentum of the ρ with respect to the nuclear medium, and evaluate the resulting widths and spectral strength in the transverse and longitudinal channels for the ρ → ππ decay. These widths are used to obtain the dilepton yields from ρ decays in relativistic heavyion collisions.

show abstract

“…[4,5] and references therein). Meanwhile, pion annihilation is the main source of dileptons which come from the hadron matter [6,7]. That is why, the proper analysis of the dilepton spectra obtained experimentally gives important observables which probe the pion dynamics in the dense nuclear matter that exists at the early stage of the collision.…”

mentioning

confidence: 99%

Pion and Quark Annihilation Mechanisms of Dilepton Production in Relativistic Heavy Ion Collisions

Anchishkin

Naryshkin²

2005

Mod. Phys. Lett. A

View full text Add to dashboard Cite

We revise the π + π − and qq annihilation mechanisms of dilepton production during relativistic heavy-ion collisions. We focus on the modifications caused by the specific features of intramedium pion states rather than by medium modification of the ρ-meson spectral density. The main ingredient emerging in our approach is a form-factor of the multi-pion (multi-quark) system. Replacing the usual delta-function the form-factor plays the role of distribution which, in some sense, "connects" the 4-momenta of the annihilating and outgoing particles. The difference between the c.m.s. velocities attributed to annihilating and outgoing particles is a particular consequence of this replacement and results in the appearance of a new factor in the formula for the dilepton production rate. We obtained that the form-factor of the multi-pion (multi-quark) system causes broadening of the rate which is most pronounced for small invariant masses, in particular, we obtain a growth of the rate for the invariant mass below two masses of the annihilating particles.Since leptons do not interact practically with the highly excited nuclear matter, they leave the reaction zone after their creation in a relativistic nucleus-nucleus collision without further rescattering. That is why, the dileptons (e + e − and µ + µ − pairs) observed in high-energy heavy ion collisions secure an excellent opportunity for obtaining information on the initial state and the evolution of the system created in a collision. The enhancement with an invariant mass of 200 ÷ 800 MeV observed by the CERES collaboration [1,2] in the production of dileptons has received recently a considerable attention and has been studied in the framework of various theoretical models (for the review, see Ref.[3]). It was found that a large part of the observed enhancement is due to the medium effects (see Refs. [4,5] and references therein). Meanwhile, pion annihilation is the main source of dileptons which come from the hadron matter [6,7]. That is why, the proper analysis of the dilepton spectra obtained experimentally gives important observables which probe the pion dynamics in the dense nuclear matter that exists at the early stage of the collision. The purpose of the present letter is to look once more on the π + π − annihilation mechanism of dilepton production from the hadron plasma by accounting the medium-induced modifications of the dilepton spectrum. In order to do this, we concentrate on the modifications which are due rather to intramedium pion states, than on the discussion of a modification of the ρ-meson spectral density. In accordance with our suggestions, the main features of a pion wave function follow from the fact that pions live a finite time in the *

show abstract

Dilepton production in ultrarelativistic heavy-ion collisions

Cited by 52 publications

References 38 publications

Chiral Symmetry Restoration and Dileptons in Relativistic Heavy-Ion Collisions

Chiral Symmetry Restoration and Dileptons in Relativistic Heavy-Ion Collisions

ρ→ππ decay in nuclear medium

Pion and Quark Annihilation Mechanisms of Dilepton Production in Relativistic Heavy Ion Collisions

Contact Info

Product

Resources

About