Is it possible to Measure the Weak Phase of a Penguin Diagram?

The $b\to d$ penguin amplitude receives contributions from internal $u$, $c$ and $t$-quarks. We show that it is impossible to measure the weak phase of any of these penguin contributions without theoretical input. However, a single assumption involving the hadronic parameters makes it possible to obtain the weak phase and test for the presence of new physics in the $b\to d$ flavour-changing neutral current.Comment: 4 pages, latex, no figures, talk given by R. Sinha at the 3rd International Conference on B Physics and CP Violation, Taipei, Taiwan, December 3-7, 1999, to appear in the Proceeding

Non-classical paths in interference experiments

In a double slit interference experiment, the wave function at the screen with both slits open is not exactly equal to the sum of the wave functions with the slits individually open one at a time. The three scenarios represent three different boundary conditions and as such, the superposition principle should not be applicable. However, most well known text books in quantum mechanics implicitly and/or explicitly use this assumption which is only approximately true. In our present study, we have used the Feynman path integral formalism to quantify contributions from non-classical paths in quantum interference experiments which provide a measurable deviation from a naive application of the superposition principle. A direct experimental demonstration for the existence of these non-classical paths is hard. We find that contributions from such paths can be significant and we propose simple three-slit interference experiments to directly confirm their existence.Comment: v2: 5 pages + 3 pages supplementary, title changed, version to appear in Physical Review Letter

Toda and Yamamoto Causality Tests Between Per Capita Saving and Per Capita GDP for India

This paper looks at the relationship between per capita saving and per capita GDP for India using the Toda and Yamamoto tests of Granger causality. Data are for 1950-2004. We distinguish between three types of saving. These are household saving, corporate saving and public saving. The results show that there is no causality between per capita GDP and per capita household saving/per capita corporate saving in either direction. However, there is bi-directional causality between per capita household saving and per capita corporate saving.Toda-Yamamoto; causality