BNL-RHIC. The measurement of the direct photon spectrum from Au$+$Au collisions at $\sqrt{s_{NN}}$ = 200 GeV is presented by the PHENIX collaboration using the external photon conversion technique for 0\%--93\% central collisions in a transverse momentum ($p_T$) range of 0.8--10 GeV/$c$. An excess of direct photons, above prompt photon production from hard scattering processes, is observed for $p_T< 6$ GeV/$c$. nonprompt direct photons are measured by subtracting the prompt component, which is estimated as $N_{coll}$-scaled direct photons from p+p collisions at 200 GeV, from the direct photon spectrum. Results are obtained for $0.8<$p_T$<6.0$ GeV/$c$ and suggest that the spectrum has an increasing inverse slope from about 0.2 GeV/$c$ to around 0.4 GeV/$c$ with increasing $p_T$. This indicates a possible sensitivity of the measurement to photons from earlier stages of the evolution of the collision. In addition, like the direct photon production, the $p_T$-integrated nonprompt direct photon yields also follow a power law scaling behavior as a function of collision system size. The exponent, $\alpha$, for the nonprompt component is found to be consistent with 1.1 with no apparent $p_T$ dependence.
Revise your submission
This submission is already
finished. Uploading a new file
will create a new version, and will require
approval by the submission coordinator before
being available publicly.
or, if you prefer, a specific version of the
record:
You can also cite the 9 data
tables
individually.
Data tables
Choose table:
Ask a Question
Your question will be emailed to those involved with the submission.
Please mention the relevant table.
Please log in to HEPData to send a question.
Notify participants
Clicking Notify Participants will email all primary uploaders and
reviewers of this submission with your message and (optionally) the status
and messages for each table.
Emails sent.
Notify coordinator
Clicking Notify Coordinator will email the coordinator of this submission
to inform them that all tables have been approved.