sin⁡2θW\sin ^{2}\theta _{W} estimate and neutrino electromagnetic properties from low-energy solar data

We report new values of weak-mixing angle ($\sin ^{2}\theta _{W}$)$,$ neutrino effective magnetic moment and the charge radius using the lowest-energy (to-date) solar neutrino data of pp, $^{7}$Be and pep spectra from phase-I and phase-II runs of Borexino experiment. The best-fit values are $\sin ^{2}\theta _{W}=$0.235$\pm$0.019 with a precision comparable to that of the combined reactor and accelerator very short-baseline experiments and $\mu _{\nu }^{eff}\leq 8.7\times 10^{-12}\mu _{B}$ at 90% C.L. with a factor of 3 improvement than the previous bounds. This leads to the improvement of all the related magnetic moment matrix elements for the Majorana-type and Dirac-type in mass basis and also improvement on bounds on the flavor magnetic moment states. The bounds on the neutrino charged radii turn out to be $-0.82\times 10^{-32}$cm$^{2}\leq \left \langle r_{\nu _{e}}^{2}\right \rangle \ \leq 1.27\times 10^{-32}$ cm$^{2}\$and $-9\times 10^{-32}$cm$^{2}\leq \left \langle r_{\nu _{\mu },\nu _{\tau }}^{2}\right \rangle \ \leq 3.1\times 10^{-31}$ cm$^{2}\$ at 90% C.L..Comment: 5 pages, 2 figures, 2 tables, Solar flux and oscillation parameter uncertainties in predictions were included. Statistical model modified. Slight changes occured in numerical results, Published in JPhy

sin⁡2(θ)w\sin^2(\theta)w estimate and bounds on nonstandard interactions at source and detector in the solar neutrino low-energy regime

We explore the implications of the Borexino experiment's real time measurements of the lowest energy part of the neutrino spectrum from the primary pp fusion process up to 0.420 MeV through the 7^Be decay at 0.862 MeV to the pep reaction at 1.44 MeV. We exploit the fact that at such low energies, the large mixing angle solution to the Mikheyev-Smirnov-Wolfenstein matter effects in the sun are small for 7^Be and pep and negligible for pp. Consequently, the neutrinos produced in the sun change their flavor almost entirely through vacuum oscillations during propagation from the sun's surface and through possible nonstandard interactions acting at the solar source and Borexino detector. We combine the different NSI effects at source and detector in a single framework and use the current Borexino data to bound NSI non-universal and flavor- changing parameters at energies below the reach of reactor neutrino experiments. We also study the implication of the current data for the weak- mixing angle at this "low-energy frontier" data from the Borexino experiment, where it is expected to be slightly larger than its value at the Z mass. We find $\sin^2(\theta)w=0.224+-0.016$, the lowest energy-scale estimate to date. Looking to the future, we use projected sensitivities to solar neutrinos in next generation dedicated solar experiments and direct dark matter detection experiments and find a potential factor five improvement in determination of the weak-mixing angle and up to an order of magnitude improvement in probing the NSI parameters space.Comment: 20 pages, 09 figures, lowest-energy value of sin^2(theta)w to date has been reported. Some text added. New sub-section(7.5) added. Published in JHE

The Changing Profile of Regional Inequality

There is a growing concern in developing and transition economies that spatial and regional inequality, of economic activity, incomes, and social indicators, is on the increase. Regional inequality is a dimension of overall inequality, but it has added significance when spatial and regional divisions align with political and ethnic tensions to undermine social and political stability. Despite these important popular and policy concerns, surprisingly there is little systematic and coherent documentation of the facts of what has happened to spatial and regional inequality over the past twenty years. This paper is an attempt to meet this gap. It provides changing scenarios of multi-dimensional inter-temporal spatial inequality and level of development in Pakistan during early 1980s and late 1990s