On the angular distribution of Λb→Λ(→Nπ)τ+τ−\Lambda_b\to\Lambda(\to N\pi)\tau^+\tau^- decay

We present a full angular distribution of the four body $\Lambda_b\to\Lambda(\to N\pi)\ell^+\ell^-$ decay where the leptons are massive and the $\Lambda_b$ is unpolarized, in an operator basis which includes the Standard Model operators, new vector and axial-vector operators, and scalar and pseudo-scalar operators. The angular coefficients are expressed in terms of transversity amplitudes. We study several $\Lambda_b\to\Lambda(\to p\pi)\tau^+\tau^-$ observables in the Standard Model and in the presence of the new operators. For our numerical analysis, we use the form factors from lattice QCD calculations.Comment: accepted by JHEP (charmonium and duality contributions included in this final version

Optimal renormalization and the extraction of the strange quark mass from moments of the τ\tau-decay spectral function

We introduce an optimal renormalization group analysis pertinent to the analysis of polarization functions associated with the $s$-quark mass relevant in $\tau$-decay. The technique is based on the renormalization group invariance constraints which lead to closed form summation of all the leading and next-to-leading logarithms at each order in perturbation theory. The new perturbation series exhibits reduced sensitivity to the renormalization scale and improved behavior in the complex plane along the integration contour. Using improved experimental and theory inputs, we have extracted the value of the strange quark mass $m_s(2{\rm GeV}) = 106.70 \pm 9.36~{\rm MeV}$ and $m_s(2{\rm GeV}) = 74.47 \pm 7.77~{\rm MeV}$ from presently available ALEPH and OPAL data respectively. These determinations are in agreement with the determinations in other phenomenological methods and from the lattice.Comment: 12 pages, 4 tables, 7 figures, v2 corresponds to version to appear in Physical Review

Tadpole cancellation in top-quark condensation

We show that quadratic divergences in top-quark condensation are cancelled when the tadpoles cancel. This latter cancellation is naturally implemented as the cancellation among the top-quark, Goldstone and Higgs contributions. We also calculate the bosonic correction terms to Gribov's mass formula for the Higgs boson. These reduce the prediction for M_H from 167 GeV to 132 GeV. The tadpole cancellation condition by itself is an independent condition on the mass of the Higgs boson which, in Gribov's U(1)_Y scenario, yields M_H \approx 117 GeV with large theoretical uncertainty. More generally, we are able to obtain all three masses, M_W, m_t and M_H, in 100 MeV to 10 TeV energy range as a function of the cut-off scale and the gauge couplings only.Comment: 7 pages, 20 eps figures. Added error estimates and a new plot (v3). To be published in Phys. Rev.

Model independent New Physics analysis in Λb→Λμ+μ−\Lambda_b\to\Lambda\mu^+\mu^- decay

We study the rare $\Lambda_b\to\Lambda\mu^+\mu^-$ decay in the Standard Model and beyond. Beyond the Standard Model we include new vector and axial-vector operators, scalar and pseudo-scalar operators, and tensor operators in the effective Hamiltonian. Working in the helicity basis and using appropriate parametrization of the $\Lambda_b \to \Lambda$ hadronic matrix elements, we give expressions of hadronic and leptonic helicity amplitudes and derive expression of double differential branching ratio with respect to dilepton invariant mass squared and cosine of lepton angle. Appropriately integrating the differential branching ratio over the lepton angle, we obtain the longitudinal polarization fraction and the leptonic forward-backward asymmetry and sequentially study the observables in the presence of the new couplings. To analyze the implications of the new vector and axial-vector couplings, we follow the current global fits to $b\to s\mu^+\mu^-$ data. While the impacts of scalar couplings can be significant, exclusive $\bar{B}\to X_s\mu^+\mu^-$ data imply stringent constraints on the tensor couplings and hence the effects on $\Lambda_b\to\Lambda\mu^+\mu^-$ are negligible.Comment: 24 pages, 5 captioned figures, 1 table, matches published version in Eur. Phys. J. C, typos correcte

India's Recent Development Dynamics and Challenges

This is Editorial&nbsp

COVID- 19 and Economic Loss of First Phase of (21- Day) Lockdown in India

To curb Covid-19 spread, Prime Minister Narendra Modi has announced a 21-day nationwide lockdown on 23 March 2020. The present study makes an attempt to estimate the state-wise and economic activity-wise economic loss of 21- day lockdown in India. The data on Net State Value Added (NSVA) by economic activity was collected for five years from the Reserve Bank of India. It was found that the percentage of the daily loss of Net State Value Added (NSVA) was considerably higher for the states of Chandigarh, Delhi and Karnataka. The manufacturing sector was expected to be the highest loser, followed by real estate, ownership of dwelling and professional services. In absolute terms, the loss was prominent in Maharashtra, Tamil Nadu and Karnataka. It is worth mentioning here that what could be the magnitude of the impact of a complete social and economic shutdown may not be easy to estimate, but it is likely to be far more severe