&quot;Neutron Optics and Physics (NOP/ BL05)&quot; at MLF in J-PARC is a beamline for<br />
studies of fundamental physics. The beamline is divided into three branches so<br />
that different experiments can be performed in parallel. These beam branches<br />
are being used to develop a variety of new projects. We are developing an<br />
experimental project to measure the neutron lifetime with total uncertainty of<br />
1 s (0.1%). The neutron lifetime is an important parameter in elementary<br />
particle and astrophysics. Thus far, the neutron lifetime has been measured by<br />
several groups; however, different values are obtained from different<br />
measurement methods. This experiment is using a method with different sources<br />
of systematic uncertainty than measurements conducted to date. We are also<br />
developing a source of pulsed ultra-cold neutrons (UCNs) produced from a<br />
Doppler shifter are available at the unpolarized beam branch. We are developing<br />
a time focusing device for UCNs, a so called &quot;rebuncher&quot;, which can increase<br />
UCN density from a pulsed UCN source. At the low divergence beam branch, an<br />
experiment to search an unknown intermediate force with nanometer range is<br />
performed by measuring the angular dependence of neutron scattering by noble<br />
gases. Finally the beamline is also used for the research and development of<br />
optical elements and detectors. For example, a position sensitive neutron<br />
detector that uses emulsion to achieve sub-micrometer resolution is currently<br />
under development. We have succeeded in detecting cold and ultra-cold neutrons<br />
using the emulsion detector.