  The high centre-of-mass energy of 200 GeV available at the Relativistic Heavy
Ion Collider (RHIC) at Brookhaven opens up the hard scattering regime in
heavy-ion collisions. Particles at large transverse momentum originate from the
early stage of the interaction and, therefore, probe the medium produced in
these collisions. To quantitatively understand the medium induced modification
of hadron production, precise measurements of identified hadrons in p+p and
d+Au systems are required. This thesis presents the high transverse momentum
measurements of neutral pions and eta mesons through their di-photon decay
channel, performed with STAR Barrel Electromagnetic Calorimeter. The medium
induced spectrum modification in d+Au collisions is also measured in comparison
to the most peripheral d+Au and to the p+p collisions. The results are
consistent with the previous STAR charged hadron measurements and with the
theory (QCD) calculations, as well as with measurements from PHENIX, another
RHIC experiment.
