Observations from LHC proton-proton operation
  This paper describes two distinct effects observed during the operation of the LHC in 2012: first, the impacts on beam parameter evolution of the end-of-squeeze instabilities encountered in the second half of the 2012 run; and, second, the very reproducible loss pattern of Beam 1 observed (while a similar pattern was negligible, if present at all, for Beam 2). Statistics for 2012 are provided and the impact on luminosity production is highlighted. 
Michael Hostettler, Giulia Papotti
physics.acc-ph