Pentaquark searches with ALICE

In this report we present the results of the data analysis for searching for possible invariant mass signals from pentaquarks in the ALICE data. Analysis was based on filtered data from real p-Pb events at psNN=5.02 TeV collected in 2013. The motivation for this project was the recent discovery of pentaquark states by the LHCb collaboration (c ¯ cuud resonance P+ c ) [1]. The search for similar not yet observed pentaquarks is an interesting research topic [2]. In this analysis we searched for a s ¯ suud pentaquark resonance P+ s and its possible decay channel to f meson and proton. The ALICE detector is well suited for the search of certain candidates thanks to its low material budget and strong PID capabilities. Additionally we might expect the production of such particles in ALICE as in heavy-ion and proton-ion collisions the thermal models describes well the particle yields and ratios [3]. Therefore it is reasonable to expect other species of hadrons, including also possible pentaquarks, to be produced with a rate predictable through the thermal model. To achieve the main goal of this project we firstly had to complete the intermediate objectives. After the precise check of the quality of the filtered data used we reconstructed the invariant mass for the f mesons through their decay to two charged kaons K+ and K􀀀 (branching ratio 48.9%). To determine the combinatorial background of uncorrelated pairs we studied three different methods, namely the like-sign method, the event-mixing technique and the multiple-rotations option. After that we reconstructed an invariant mass distribution for proton and f meson and we compared it with the reconstructed invariant mass for proton and side bands of the f meson peak. At the end we outlined the next steps for this analysis, which should be achieved in the near future.