PrimEx II Results: Precision Measurement of the Neutral Pion Lifetime

The PrimEx experiments in Hall B at Jefferson lab were aimed to perform a precision measurement of the $\pi^{\mathrm{0}}\to \gamma \gamma $ decay width via Primakoff effect. A combination of a state-of-the-art high resolution lead tungstate hybrid electromagnetic calorimeter and a tagged photon beam offered a great advantage in reducing experimental uncertainties. The published result from the first (PrimEx I) experiment has 2.8{\%} accuracy. The second (PrimEx II) experiment with several times more statistics than the PrimEx I and an improved systematics was aimed to achieve a better than 2.0{\%} precision. An updated PrimEx II result will be presented.