Color reconnection and event-by-event fluctuations of mean transverse   momentum in proton-proton collisions at sqrt_s = 7 TeV in PYTHIA6.4
  Based on PYTHIA6.428, event-by-event fluctuations of the mean transverse momentum in proton- proton collisions at sqrt_s = 7 TeV are studied using several measures of the fluctuations. The study compares results of the fluctuations for events where color reconnection is turned on, with those where color reconnection is turned off. The comparison reveals that some of the fluctuation measures are much more sensitive to color reconnection than others. Through the comparison it is demonstrated for the first time that for proton-proton collisions at the Large Hadron Collider, these sensitive measures of the mean transverse momentum fluctuations can serve as alternative probes to color reconnection and color reconnection is a non-trivial source of the event-by-event fluctuations. 
Qingjun Liu and Wei-Qin Zhao
hep-ph hep-ex