SN0304 : Z-scaling and Prompt Photon Production in pp Collisions at STAR
Updated on Mon, 2007-06-18 19:57. Originally created by chajecki on 2007-06-18 19:57.
| Author(s) | : | M. Tokarev |
| Date | : | Sep. 11, 1997 |
| File(s) | : | sn0304.ps.gz |
| Abstract | : | The new scaling, $z$-scaling, is used to study the prompt photon production in $pp$-collisions at high energies. The scaling function $H(z)$ is expressed via the inclusive cross section of photon production $Ed^3\sigma/dq^3$ and the particle multiplicity density $dN/d\eta$ at pseudorapidity $\eta=0$. The dependence of $H(z)$ on the scaling variable\ \ $z = {s_{x}^{1/2}}/({\Delta M \cdot dN(0)/d\eta})$, the center-of-mass energy ${\sqrt {s}}$ is investigated. The available experimental data on direct photon production in $pp$ interactions obtained at the ISR at the energy ${\sqrt {s}}=23, 63~GeV$ confirm the scaling and are used to construct $H(z)$. Based on the universality of $H(z)$ the dependence of the invariant cross section for the $pp\rightarrow \gamma X$ process on photon momentum $q_T$ at RHIC energy $\sqrt s = 200, 500~GeV$ were predicted. The systematic errors for the cross section using the energy and angular resolution of the STAR EMC detector were estimated. The obtained results can be of interest for future experiments at RHIC to search for signals of the quark-gluon plasma formation in hadron-nucleus and nucleus-nucleus collisions.
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