  Quasi-periodic pulsations (QPP) seen in the time derivative of the GOES soft
X-ray light curves are analyzed for the near-limb X3.2 event on 14 May 2013.
The pulsations are apparent for a total of at least two hours from the
impulsive phase to well into the decay phase, with a total of 163 distinct
pulses evident to the naked eye. A wavelet analysis shows that the
characteristic time scale of these pulsations increases systematically from
$\sim$25 s at 01:10 UT, the time of the GOES peak, to $\sim$100 s at 02:00 UT.
A second ridge in the wavelet power spectrum, most likely associated with
flaring emission from a different active region, shows an increase from
$\sim$40 s at 01:40 UT to $\sim$100 s at 03:10 UT. We assume that the QPP that
produced the first ridge result from vertical kink-mode oscillations of the
newly formed loops following magnetic reconnection in the coronal current
sheet. This allows us to estimate the magnetic field strength as a function of
altitude given the density, loop length, and QPP time scale as functions of
time determined from the GOES light curves and RHESSI images. The calculated
magnetic field strength of the newly formed loops ranges from about $\sim$500 G
at an altitude of 24 Mm to a low value of $\sim$10 G at 60 Mm, in general
agreement with the expected values at these altitudes. Fast sausage mode
oscillations are also discussed and cannot be ruled out as an alternate
mechanism for producing the QPP.
