High transverse momentum charged kaon production in center of mass energies = 200 GeV gold-gold collisons at RHIC

Relativistic heavy-ion collisions compress nuclei to states of extremely high temperature and density. Under these conditions, phenomenological models as well as Lattice QCD calculations predict a phase transition in nuclear matter, in which quarks and gluons are no longer bound in hadrons but instead can move freely inside the interaction volume. This transition would be accompanied by a restoration of chiral symmetry, and the resulting state is called Quark Gluon Plasma (QGP). The observation of this phase transition and the study of the dynamics and properties of the deconfined phase have important consequences, both for the understanding of QCD and for cosmology, as it recreates conditions that existed for the universe as a whole some 10 μs after the Big Bang.; Charged Kaons can provide signals of the formation of a QGP. First, they carry a large fraction of the strange quark content of the hadrons produced in the collision. The amount of strangeness can probe the degree of chemical equilibrium in the system. Chemical equilibrium may occur in a QGP or a normal hadronic system, but it occurs much more quickly in a QGP. Another benefit of measuring charged Kaons is that they provide identified spectra at high transverse momentum. A suppression of high momentum particles in heavy ion collisions relative to smaller systems can suggest partonic energy loss in a color deconfined medium.; The technique used in this analysis to identify charged Kaons is the topological reconstruction of their one-prong decays: e.g. K± → μ± + ν_μ (63.5%) or K± → π± + π 0 (21.2%). This is similar to traditional ‘V0’ reconstruction, except we observe the charged parent and daughter of the decay. The main tracking device in the STAR detector is a Time Projection Chamber (TPC), which is a cylindrical ionization chamber 2 meters in radius and 4.5 meters long having pad readouts at the endcaps. This allows 3D reconstruction of charged particle trajectories.; Presented in this Dissertation is a measurement of the charged Kaon spectra in $NSN$ = 200 GeV Au-Au collisions at the Relativistic Heavy Ion Collider during 2001. Our data set is about 3 million “central” events and 3 million “minimum bias” events.; Spectra are presented out to transverse momenta of 4 GeV/c, and the ratio K−/K+ is presented as a function of collision centrality and rapidity. For the most central collisions, the charged Kaon yield ((K− + K+)/2) at midrapidity is dN/dy = 55. For comparison this value in 130 GeV collisions was dN/dy = 50. We observe a suppression of high p_T charged Kaons in central collisions relative to peripheral. This suppression has a number of possible sources, one of which may be partonic energy loss in a colored medium. The measurements presented here further supplement the rich data being produced at RHIC and contribute to understanding the physics of heavy ion collisions at $NSN$ = 200 GeV.