First results from the ALICE experiment at LHC

The ALICE experiment complies a unique detector system among the LHC experiments, which is optimized to the studies of hot and dense matter created in the high-energy heavy-ion collisions at LHC. ALICE has been successfully accumulating data of proton-proton (p+p) collisions at various collision energies since the first collisions were realized at √s=900 GeV. In this report, results from ALICE with the first collisions at LHC are presented, which includes dependence of charged particle multiplicity on the collision energies, multiplicity distribution, particle spectra and their multiplicity dependence, transverse momentum distribution, and antiproton to proton yield ratio. Results demonstrating performance of detector subsystems are also shown. (author)