The results from LHCf: Very forward measurements for cosmic ray interactions

The LHCf experiment is an unique dedicated experiment for measurement of very forward particle production relevant to cosmic-ray air shower developments by using small electromagnetic imaging calorimeters at the zero degree of the LHC interaction point, IP1. The operationa with p-p collisions at s = 900 GeV and 7 TeV have been done in 2009 and 2010. The results of forward production spectra of photons and π0s are compared with the existing cosmic ray interaction models, SYBILL, QGSJETII, DPMJET3, and EPOS1.99. None of them could completely reproduce the data. On-going hadron analysis will be also important to understand inelas-ticity of collisions. LHCf has also completed data taking for LHC p-Pb collisions to study nuclear effect relevant to air shower development. This is also very important to validate composition measurements by air-shower experiments based on XMAX. Current achievement of the LHCf experiment and possible future experiments at p-A and/or A-A collisions at LHC and RHIC are presented.