LHCf Measurements of Very Forward Particles at LHC

Abstract

The LHC forward experiment (LHCf) is specifically designed for measurements of the very forward ($\eta$$>$8.4) production cross sections of neutral pions and neutrons at Large Hadron Collider (LHC) at CERN. LHCf started data taking in December 2009, when the LHC started to provide stable collisions of protons at $\sqrt{s}$=900\,GeV. Since March 2010, LHC increased the collision energy up to $\sqrt{s}$=7\,TeV. By the time of the symposium, LHCf collected 113k events of high energy showers (corresponding to $\sim$7M inelastic collisions) at $\sqrt{s}$=900\,GeV and $\sim$100M showers ($\sim$14 nb$^{-1}$ of integrated luminosity) at $\sqrt{s}$=7\,TeV. Analysis results with the first limited sample of data demonstrate that LHCf will provide crucial data to improve the interaction models to understand very high-energy cosmic-ray air showers.Comment: Invited talk given at XVI International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI 2010), Batavia, IL, USA, 28 June 2 July 2010. 6 pages, 10 figure