Relativistic Heavy Ions Experiment IV Photons and Neutral Mesons.
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Transcript of Relativistic Heavy Ions Experiment IV Photons and Neutral Mesons.
Thermal photons fromthe hot medium
Jet-photon conversionin the medium
Additional Photon Sources in A+A
kt-broadening +Ti = 205MeV
no kt-broadening +Ti = 270MeV
Turbide, Rapp, Gale, Phys. Rev. C 69 (014902), 2004
Prompt and Thermal Photons in Pb+Pb at 158AGeV
Ti = 214 - 255 MeVQGP + HG + pQCD(Non-boost inv. hydro)
Huovinen, Ruuskanen, Räsänen (Nucl. Phys. A 650 (227) 1999)
Ti = 213 - 234 MeVPure HG + pQCD(Non-boost inv. hydro)
Ti = 335 MeV, = 0,2 fm/c
QGP + HG + pQCC(Bjorken hydro)
Svrivastava (nucl-th/0411041)
250 < Ti < 370 MeV,0,5 < < 3 fm/c
QGP + HG + pQCDRenk (Phys.Rev.C67:064901,2003)
Ti = 250 - 270 MeV, = 0,5 fm/c
QGP + HG + pQCD without kT
Ti = 205 MeV, = 1 fm/c
QGP + HG + pQCD with kT
Turbide, Rapp, Gale (Phys.Rev.C69:014903,2004 )
Theoretical Descriptions and Initial Temperatures Ti
Direct Photon Measurement via Virtual Photons
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phase space factor
form factorinvariant mass of Dalitz pair
invariant mass of virtual photon
Compton
q
g q
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0
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S/B=~1
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data
incl.
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*
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RR
RR
calculated from Dalitz formula
measuredRdata ÷
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Rdirect
incl.
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measured with EMCal
Direct Photon Measurement via Virtual Photons