Precision Measurement of the Position-space Wave Functions of Gravitationally Bound Ultracold Neutrons

Gravity is the most familiar force at our natural length scale. However, it is still exotic from the view point of particle physics. The first experimental study of quantum effects under gravity was performed using a cold neutron beam in 1975. Following this, an investigation of gravitationally bound quantum states using ultracold neutrons was started in 2002. This quantum bound system is now well understood, and one can use it as a tunable tool to probe gravity. In this paper, we review a recent measurement of position-space wave functions of such gravitationally bound states, and discuss issues related to this analysis, such as neutron loss models in a thin neutron guide, the formulation of phase space quantum mechanics, and UCN position sensitive detectors. The quantum modulation of neutron bound states measured in this experiment shows good agreement with the prediction from quantum mechanics.Comment: 13 pages, 5 figure

A Search for non-Newtonian force in a precision measurement of the scattering of slow neutrons in Xenon gas

An experimental search for non-newtonian, gravity-like force in a precision measurement of the scattering of slow neutrons in Xenon gas is proposed. A preliminary experiment with small statistics of 25 hours irradiation time was performed and the observed scattering distribution is consistent with the expectation with no additional forces. A 95% CL limit on the coupling strength for a hypothetical force of 1 nm interaction range was evaluated to be 2*10^-15. The expected sensitivity for a planned high statistics runs is discussed.Comment: 5pages, 3 figure

Can a Measurement of the Bs−B‾sB_{s} - {\overline{B}}_{s} Mass Difference Establish the CKM Paradigm?

We present a reanalysis of the allowed region in the $\rho - \eta \,$ plane of the CKM matrix, which follows from our present knowledge of the theoretical and experimental parameters associated with quark mixing and CP violation. Besides providing updated expectations for the angles of the unitarity triangle, this reanalysis predicts a range of allowed values for the $B_{s} - {\overline{B}}_{s} \,$ mass difference $\Delta m_{s}$. We argue that while values of \Delta m_{s} \lsim 10 (ps)^{-1} could be consistent with a non-CKM origin for CP violation in the neutral Kaon system, larger values for $\Delta m_{s}$ would provide strong support for the CKM paradigm.Comment: 9 pages, LaTex, 3 uuencoded eps figures(embedded with epsfig.sty)