On Some properties of Di-hadronic states

The binding energies of di- hadronic states have been calculated assuming a 'molecular' interaction provided by the asymptotic expression of the residual confined gluon exchange potential between the component hadrons in the system. Meson- meson and meson- baryon states have been studied in detail and a mass formula has been used to calculate total mass of the 'molecules'.Comment: 11 page

Reducing Penguin Pollution

The most common decay used for measuring 2beta_s, the phase of Bs-Bsbar mixing, is Bs -> J/psi phi. This decay is dominated by the colour-suppressed tree diagram, but there are other contributions due to gluonic and electroweak penguin diagrams. These are often referred to as "penguin pollution" (PP) because their inclusion in the amplitude leads to a theoretical error in the extraction of 2beta_s from the data. In the standard model (SM), it is estimated that the PP is negligible, but there is some uncertainty as to its exact size. Now, phi_s^{c\bar{c}s} (the measured value of 2beta_s) is small, in agreement with the SM, but still has significant experimental errors. When these are reduced, if one hopes to be able to see clear evidence of new physics (NP), it is crucial to have the theoretical error under control. In this paper, we show that, using a modification of the angular analysis currently used to measure phi_s^{c\bar{c}s} in Bs -> J/psi phi, one can reduce the theoretical error due to PP. Theoretical input is still required, but it is much more modest than entirely neglecting the PP. If phi_s^{c\bar{c}s} differs from the SM prediction, this points to NP in the mixing. There is also enough information to test for NP in the decay. This method can be applied to all Bs/Bsbar -> V1 V2 decays.Comment: 17 pages, latex, extensive discussion of theoretical error added, reference added. Further revision: even more detailed discussion of theoretical error added, as well as an explanation of why the NP strong phase is negligibl

Coherence resonance in an unijunction transistor relaxation oscillator

The phenomenon of coherence resonance (CR) is investigated in an unijunction transistor relaxation oscillator (UJT-RO) and quantified by estimating the normal variance (NV). Depending upon the measuring points two types of NV curves have been obtained. We have observed that the degradations in coherency at higher noise amplitudes in our system is probably the result of direct interference of coherent oscillations and the stochastic perturbation. Degradation of coherency may be minimal if this direct interference of noise and coherent oscillations is eliminated.Comment: 4 pages, Coherence resonace, Uni junction relaxation oscillato