First Results from CMS on QCD, Quarkonia, and Heavy-Flavour Physics in proton-proton Collisions at $\sqrt{s}$=7 TeV

The very good performance of the CMS detector [1] allows to establish a rich set of physics measurements with the first few hundred nb$^{-1}$ of LHC pp-collision data collected at $\sqrt{s}=7$ TeV. The first particle multiplicity measurements can be used to tune the Underlying Event description in Parton Shower Monte-Carlo (MC). Given the advanced level of jet commissioning, the differential cross-section of inclusive jet production has been measured from 20 GeV to 500 GeV in transverse momentum of the leading jet. Measurements of the hadronic event shapes have the sensitivity to tune the Matrix Element MC. B-tagging techniques can be exploited to measure the inclusive b-jet cross-section. The b-jet $\rightarrow \mu+X$ cross-section is also measured, showing an underestimation of the Next-to-Leading-Order (NLO) calculations at very low $p_T$ and central pseudorapidity ($\eta$). Finally, first measurements of the $J/\psi\rightarrow\mu\mu$ and $\Upsilon\rightarrow\mu\mu$ cross-sections were performed, thanks to the high muon trigger efficiency and very good tracking resolution, and compared with theoretical models for quarkonia production.