Determination of pseudo-Goldstone boson-photon coupling by the differential time delay of pulsar signals

Pseudo-Goldstone bosons couple with photons through a P and T violating interaction of the form ${\cal {L_I}}=g_{a\gamma \gamma}~ a F\tilde F$. Strong magnetic fields in rotating compact stars induce a non-zero ${\vec E}\cdot{\vec B}$ outside the stellar surface which acts as a source for the pseudo-scalar field. Pulsar signals propagating through this pseudo-scalar `hair' suffer a differential time lag between the left and the right circularly polarised modes because of the P and T violating pseudoscalar boson-photon interaction. Determination of this time lag upto a microsecond accuracy can lead to a measurment of (or rule out) pseudo-Goldstone boson-photon coupling upto $g_{a \gamma \gamma}\leq 4.6 \times 10^{-9}~GeV^{-1}$.Comment: Plain TeX,12 pages,IP/BBSR/92-9

Identification of Highly Deformed Even-Even Nuclides in the Neutron- and Proton-Rich Regions of the Nuclear Chart from the B(E2) and E2 Predictions in the Generalized Differential Equation Model

We identify here possible occurrence of large deformations in the neutron- and proton-rich regions of the nuclear chart from extensive predictions of the values of the reduced quadrupole transition probability B-E2 for the transition from the ground state to the first 2+ state and the corresponding excitation energy E2 of even-even nuclei in the recently developed Generalized Differential Equation model exclusively meant for these physical quantities. This is made possible from our analysis of the predicted values of these two physical quantities and the corresponding deformation parameters derived from them such as the quadrupole deformation beta-2, the ratio of beta-2 to the Weisskopf single-particle beta-2 and the intrinsic electric quadruplole moment , calculated for a large number of both known as well as hitherto unknown even-even isotopes of Oxygen to Fermium (Z=8 to 100). Our critical analysis of the resulting data convincingly support possible existence of large collectivity for the nuclides 30,32 Ne, 34 Mg, 60 Ti, 42,62,64 Cr, 50,68 Fe, 52,72 Ni, 72,70,96 Kr, 74,76 Sr,78,80,106,108 Zr , 82,84,110,112 Mo, 140 Te,144 Xe, 148 Ba, 122 Ce, 128,156 Nd, 130,132,158,160 Sm and 138,162,164,166 Gd, whose values of beta-2 are found to exceed 0.3 and even 0.4 in some cases. Our findings of large deformations in the exotic neutron-rich regions support the existence of another Island of Inversion in the heavy-mass region possibly caused by breaking of the N=70 sub-shell closure.Comment: 15 figure