The first collisions in the Large Hadron Collider (LHC) at CERN with beam energy of 3.5 TeV happened in March 2010 marking the start of the LHC research program. In the early periods of LHC operating the understanding of ATLAS detector performance is of major priority. The observation of high P_T φ mesons in the dense jet environment provides important information about the performance of ATLAS’s tracking system, allows better tunning of the strange sector iv various generators and can also be applied for s-quark tagging.

We shall present the method for φ mesons reconstruction and background estimation and subtraction. φ mesons with P_T as high as 35 GeV inside energetic jets are extracted using the modest integrated luminosity of approximately 0.4 pb^-1. To the best of our knowledge this is the first time that such φ mesons are observed. The P_T spectrum as well as the x distribution of these φ mesons are computed after applying different background subtraction techniques. The data appears to be in reasonable agreement with Monte Carlo predictions.