Semileptonic decay of BcB_c meson into ccˉc\bar c states in a QCD potential model

The slope and curvature of Isgur Wise function for $B_{c}$ meson is computed in a QCD potential model in two different approaches of choosing the perturbative term of the Cornell potential. Based on heavy quark effective theory the exclusive semileptonic decay rates of $B_c$ meson into the $c\bar c\ (\eta_c,J/\psi)$states are exploited. Spin symmetry breaking effects are ignored upto a particular point and the form factors are connected with Isgur-Wise function for other kinematic point since the recoil momentum of$c\bar c$from$B_{c}$ is small due to its heavy mass.Comment: 13 pages, 4 tables, 4 figures,Accepted to Int.J.Mod.Phys.

Glass Ceilings or Glass Doors? Wage Disparity Within and Between Firms

We investigate whether immigrant and minority workers’ poor access to high-wage jobs – that is, glass ceilings – is attributable to poor access to jobs in high-wage firms, a phenomenon we call glass doors. Our analysis uses linked employer-employee data to measure mean- and quantile-wage differentials of immigrants and ethnic minorities, both within and across firms. We find that glass ceilings exist for some immigrant groups, and that they are driven in large measure by glass doors. For some immigrant groups, the sorting of these workers across firms accounts for as much as half of the economy-wide wage disparity they face.glass ceilings, wage differentials, immigration, visible minorities, quantile regression, linked employer-employee data

Oscillations in active region fan loops: Observations from EIS/{\it Hinode} and AIA/SDO

Active region fan loops in AR 11076 were studied, in search of oscillations, using high cadence spectroscopic observations from EIS on board Hinode combined with imaging sequences from the AIA on board SDO. Spectra from EIS were analyzed in two spectral windows, \FeXII 195.12 \AA and \FeXIII 202.04 \AA along with the images from AIA in 171 \AA and 193 \AA channels. We find short ($<$3 min) and long ($\approx$9 min) periods at two different locations. Shorter periods show oscillations in all the three line parameters and the longer ones only in intensity and Doppler shift but not in line width. Line profiles at both these locations do not show any visible blue-shifted component and can be fitted well with a single Gaussian function along with a polynomial background. Results using co-spatial and co-temporal data from AIA/SDO do not show any significant peak corresponding to shorter periods, but longer periods are clearly observed in both 171 \AA and 193 \AA channels. Space-time analysis in these fan loops using images from AIA/SDO show alternate slanted ridges of positive slope, indicative of outward propagating disturbances. The apparent propagation speeds were estimated to be 83.5 $\pm$ 1.8 \kms and 100.5 $\pm$ 4.2 \kms, respectively, in the 171 \AA and 193 \AA channels. Observed short period oscillations are suggested to be caused by the simultaneous presence of more than one MHD mode whereas the long periods are suggested as signatures of slow magneto-acoustic waves. In case of shorter periods, the amplitude of oscillation is found to be higher in EIS lines with relatively higher temperature of formation. Longer periods, when observed from AIA, show a decrease of amplitude in hotter AIA channels which might indicate damping due to thermal conduction owing to their acoustic nature.Comment: Accepted for publication in Solar Physic