All
All

What are you looking for?

All
Projects
Organizations

Quick search

  • Projects supported by TA ČR
  • Excellent projects
  • Projects with the highest public support
  • Current projects

Smart search

  • That is how I find a specific +word
  • That is how I leave the -word out of the results
  • “That is how I can find the whole phrase”

Low-p(T) e(+)e(-) Pair Production in Au plus Au Collisions at root s(NN)=200 GeV and U plus U Collisions at root s(NN)=193 GeV at STAR

Result description

We report first measurements of e(+)e(-) pair production in the mass region 0.4 < M-ee < 2.6 GeV/c(2) at low transverse momentum (p(T) < 0.15 GeV/c) in noncentral Au + Au collisions at root s(NN) = 200 GeV and U + U collisions at root s(NN) = 193 GeV. Significant enhancement factors, expressed as ratios of data over known hadronic contributions, are observed in the 40%-80% centrality of these collisions. The excess yields peak distinctly at low p(T) with a width (root < p(T)(2)>) between 40 and 60 MeV/c. The absolute cross section of the excess depends weakly on centrality, while those from a theoretical model calculation incorporating an in-medium broadened rho spectral function and radiation from a quark gluon plasma or hadronic cocktail contributions increase dramatically with an increasing number of participant nucleons. Model calculations of photon-photon interactions generated by the initial projectile and target nuclei describe the observed excess yields but fail to reproduce the p(T)(2) distributions.

Keywords

STARheavy ion collisions

The result's identifiers

Alternative languages

  • Result language

    angličtina

  • Original language name

    Low-p(T) e(+)e(-) Pair Production in Au plus Au Collisions at root s(NN)=200 GeV and U plus U Collisions at root s(NN)=193 GeV at STAR

  • Original language description

    We report first measurements of e(+)e(-) pair production in the mass region 0.4 < M-ee < 2.6 GeV/c(2) at low transverse momentum (p(T) < 0.15 GeV/c) in noncentral Au + Au collisions at root s(NN) = 200 GeV and U + U collisions at root s(NN) = 193 GeV. Significant enhancement factors, expressed as ratios of data over known hadronic contributions, are observed in the 40%-80% centrality of these collisions. The excess yields peak distinctly at low p(T) with a width (root < p(T)(2)>) between 40 and 60 MeV/c. The absolute cross section of the excess depends weakly on centrality, while those from a theoretical model calculation incorporating an in-medium broadened rho spectral function and radiation from a quark gluon plasma or hadronic cocktail contributions increase dramatically with an increasing number of participant nucleons. Model calculations of photon-photon interactions generated by the initial projectile and target nuclei describe the observed excess yields but fail to reproduce the p(T)(2) distributions.

  • Czech name

  • Czech description

Classification

  • Type

    Jimp - Article in a specialist periodical, which is included in the Web of Science database

  • CEP classification

  • OECD FORD branch

    10304 - Nuclear physics

Result continuities

  • Project

    Result was created during the realization of more than one project. More information in the Projects tab.

  • Continuities

    I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Others

  • Publication year

    2018

  • Confidentiality

    S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Data specific for result type

  • Name of the periodical

    Physical Review Letters

  • ISSN

    0031-9007

  • e-ISSN

  • Volume of the periodical

    121

  • Issue of the periodical within the volume

    13

  • Country of publishing house

    US - UNITED STATES

  • Number of pages

    8

  • Pages from-to

  • UT code for WoS article

    000445603400009

  • EID of the result in the Scopus database

    2-s2.0-85054011284