Photon and neutral pion production in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">Au</mml:mi><mml:mo>+</mml:mo><mml:mi mathvariant="normal">Au</mml:mi></mml:mrow></mml:math>collisions at<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msqrt><mml:mrow><mml:msub><mml:mi>s</mml:mi><mml:mrow><mml:mi>N</mml:mi><mml:mi>N</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>130</mml:mn><mml:mspace width="0.3em"/><mml:mi mathvariant="normal">GeV</mml:mi></mml:mrow></mml:math>
Аннотация
We report inclusive photon measurements about midrapidity y 0.5 from 197 Au+ 197 Au collisions at s NN = 130 GeV at RHIC. Photon pair conversions were reconstructed from electron and positron tracks mea- sured with the Time Projection Chamber (TPC) of the STAR experiment. With this method, an energy resolution of E / E 2% at 0.5 GeV has been achieved. Reconstructed photons have also been used to measure the transverse momentum p t spectra of 0 mesons about midrapidity y 1 via the 0 decay channel. The fractional contribution of the 0 decay to the inclusive photon spectrum decreases by 20% 5% between p t = 1.65 GeV/ c and p t = 2.4 GeV/ c in the most central events, indicating that relative to 0 decay the contribution of other photon sources is substantially increasing.
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