  A search is presented for free heavy long-lived fractionally charged
particles produced in pp collisions at sqrt(s) = 7 TeV. The data sample was
recorded by the CMS detector at the LHC and corresponds to an integrated
luminosity of 5.0 inverse femtobarns. Candidate fractionally charged particles
are identified by selecting tracks with associated low charge measurements in
the silicon tracking detector. Observations are found to be consistent with
expectations for background processes. The results of the search are used to
set upper limits on the cross section for pair production of fractionally
charged, massive spin-1/2 particles that are neutral under SU(3)[C] and
SU(2)[L]. We exclude at 95% confidence level such particles with electric
charge +/-2e/3 with masses below 310 GeV, and those with charge +/-e/3 with
masses below 140 GeV.
