STAR inner tracking upgrade - A performance study

Abstract

Anisotropic flow measurements have demonstrated development of partonic collectivity in $200\mathrm{GeV}$ Au+Au collisions at RHIC. To understand the partonic EOS, thermalization must be addressed. Collective motion of heavy-flavor (c,b) quarks can be used to indicate the degree of thermalization of the light-flavor quarks (u,d,s). Measurement of heavy-flavor quark collectivity requires direct reconstruction of heavy-flavor hadrons in the low $\pt$ region. Measurement of open charm spectra to high $\pt$ can be used to investigate heavy-quark energy loss and medium properties. The Heavy Flavor Tracker (HFT), a proposed upgrade to the STAR experiment at midrapidity, will measure $v_2$ of open-charm hadrons to very low $\pt$ by reconstructing their displaced decay vertices. The innermost part of the HFT is the PIXEL detector (made of two low mass monolithic active pixel sensor layers), which delivers a high precision position measurement close to the collision vertex. The Intermediate Silicon Tracker (IST), a 1-layer strip detector, is essential to improve hit identification in the PIXEL detector when running at full RHIC-II luminosity. Using a full GEANT simulation, open charm measurement capabilities of STAR with the HFT will be shown. Its performance in a broad $\pt$ range will be demonstrated on $v_2$ ($\pt > 0.5\mathrm{GeV}/c$) and $R_{\mathrm{CP}}$ ($\pt < 10\mathrm{GeV}/c$) measurements of $\D$ meson. Results of reconstruction of $\Lc$ baryon in heavy-ion collisions are presented.

to appear in EPJ C (Hot Quarks 2008 conference volume)

References in corpus (5)

• Energy Loss and Flow of Heavy Quarks in Au+Au Collisions at sqrt(s_NN) = 200 GeV
• Erratum: Transverse momentum and centrality dependence of high-\pt\ non-photonic electron suppression in Au+Au collisions at \sqrtsNN\ = 200 GeV
• Identified baryon and meson distributions at large transverse momenta from Au+Au collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV
• Energy dependence of charged pion, proton and anti-proton transverse momentum spectra for Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV
• Suppression of Non-photonic Electrons from Enhancement of Charm Baryons in Heavy Ion Collisions

Cited by in corpus (1)

• Heavy Flavor Tracker (HFT) : A new inner tracking device at STAR