Neutron lifetime experiment with pulsed cold neutrons at J-PARC

A free neutron decays in a lifetime of about 880 s. Although the neutron lifetime is an important parameter in modern physics, there is a 4.6 sigma (9.5 s) discrepancy between the experimental results of two typical methods: the beam method and the storage method. We are carrying out a new experimental method to measure the neutron lifetime using a pulsed neutron beam at J-PARC MLF BL05 to determine the cause of the discrepancy, whether overlooked systematic uncertainties or new physics. A review of our experiment including the first physics result with acquired data during 2014 - 2016 and the status using new neutron optics are presented here.