15147590
Particle physics bounds from the Hulse-Taylor binary.
The orbital period of the binary pulsar PSR 1913+16 has been observed to decrease at the rate of 2.40{times}10{sup {minus}12} s/s which agrees with the prediction of the quadropole formula for gravitational radiation to within one percent. The decrease in orbital period may also occur by radiation of other massless particles such as scalars and pseudoscalar Nambu-Goldstone bosons. Assuming that this energy loss is less than one percent of the gravitational radiation, we can establish bounds on couplings of these particles to nucleons. For a scalar nucleon coupling of the form {ital g}{sub {ital s}}{phi}{bar {psi}}{psi} we find that {ital g}{sub {ital s}}{lt}3{times}10{sup {minus}19}. From the radiation loss of massless Goldstone bosons we establish the upper bound {theta}{ital g}{sub {ital p}}{lt}10{sup {minus}16} on the QCD vacuum angle {theta} and the pseudoscalar nucleon coupling constant {ital g}{sub {ital p}}. {copyright} {ital 1996 The American Physical Society.}
11918846
Neutrino and astroparticle physics: Working group report
The contributions made to the Working Group activities on neutrinos and astrophysics are summarized in this article. The topics discussed were inflationary models in Raman-Sundrum scenarios, ultra high energy cosmic rays and neutrino oscillations in 4 flavour and decaying neutrino models.
117886121
Field-theoretical treatment of neutrino oscillations
We discuss the field-theoretical approach to neutrino oscillations. This approach includes the neutrino source and detector processes and allows to obtain the neutrino transition or survival probabilities as cross sections derived from the Feynman diagram of the combined source -- detection process. In this context, the neutrinos which are supposed to oscillate appear as propagators of the neutrino mass eigenfields, connecting the source and detection processes.
121168530
Quantum cosmology of the superstring universe
Abstract We study the quantum cosmology of the string universe obtained by embedding the Robertson-Walker metric in the non-linear model of Antoniadis, Bachas, Ellis and Nanopoulos (ABEN). We find that the quantum model has some unusual features not seen in the classical model. Initially, the universe exists in a series of metastable bound states with scale factor taking discrete values. Then the universe tunnels through a barrier and comes out in an inflationary state. This tunneling (or evolution in imaginary time) also has the effect of heating up the matter field so that we have the conditions of chaotic inflation. Our asymptotic solutions agree with those obtained from the classical Einstein equations by ABEN.
15412351
Production process dependence of neutrino flavor conversion
We perform a covariant wave-packet analysis of neutrino oscillations taking into account the lifetime of the neutrino production process . We find that flavor oscillations in space are washed out when the neutrinos are produced from long lived resonances - and what may be observed in appearance/disappearance experiments is a uniform conversion probability independent of distance. The lifetime of the resonance which produces the neutrinos acts as the the effective baseline of the experiment. 
For this reason the LSND experiment where neutrinos are produced from muon decay has two orders of magnitude more sensitivity to neutrino mass square difference than other experiments where the neutrinos are produced from pion or kaon decays.
118059039
Determination of the age of the earth from Kamland measurement of geo-neutrinos
The low energy component of the antineutrino spectrum observed in the recent Kamland experiment has significant contribution from the radioactive decay of $^{238}U$ and $^{232}Th$ in the crust and mantle of the earth. By taking the ratio of the antineutrino events obeserved in two different energy ranges we can determine the present value $[Th/U]$ independent of the U,Th distribution in the earth. Comparing with the r-process initial value of $[Th/U]_0$ we determine the age of the earth as a function of $\Delta m^2$ and $Sin^2 2 \theta$. We find that the age of the earth determined from KamLAND data matches the age of solar system ($4.5 Gyrs$ from meteorites) for the LMA-I solution. For the LMA-II solution the age of the earth does not match the solar system age at 90 % C.L.
28965135
Effect of channel coupling on spin distribution at and above Coulomb barrier energies.
The energy dependence of the fusion spin distribution has been studied in terms of its scaled moments. It is shown that the effect of channel coupling on spin distribution, particularly the effect of coupling of the shape degree of freedom to the translational motion, is much stronger at and above Coulomb barrier energies, even though the effect on fusion cross section is largest at sub-barrier energies.