Tata Institute of Fundamental Research

About: Tata Institute of Fundamental Research is a education organization based out in Mumbai, Maharashtra, India. It is known for research contribution in the topics: Magnetization & Large Hadron Collider. The organization has 7786 authors who have published 21742 publications receiving 622368 citations. The organization is also known as: TIFR.

IndIGO and LIGO-India: Scope and Plans for Gravitational Wave Research and Precision Metrology in India

Abstract: Initiatives by the IndIGO (Indian Initiative in Gravitational Wave Observations) Consortium during the past three years have materialized into concrete plans and project opportunities for instrumentation and research based on advanced interferometer detectors . With the LIGO-India opportunity, this initiative has a taken a promising path towards significant participation in gravitational wave (GW) astronomy and research, and in developing and nurturing precision fabrication and measurement technologies in India. The proposed LIGO-India detector will foster integrated development of frontier GW research in India and will provide opportunity for substantial contributions to global GW research and astronomy. Widespread interest and enthusiasm about these developments in premier research and educational institutions in India lead to the expectation that there will be a grand surge of activity in precision metrology, instrumentation, data handling and computation etc. in the context of LIGO-India. I discuss the scope of such research in the backdrop of the IndIGO action plan and the LIGO-India project.

Diagnosing New Physics in $b \to c \, \tau \, \nu_\tau$ decays in the light of the recent BaBar result

Abstract: The BABAR Collaboration has recently reported the measurement of the ratio of the branching fractions of $\overline{B}\ensuremath{\rightarrow}D({D}^{*}){\ensuremath{\tau}}^{\ensuremath{-}}{\overline{\ensuremath{ u}}}_{\ensuremath{\tau}}$ to $\overline{B}\ensuremath{\rightarrow}D({D}^{*}){\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{ u}}}_{\ensuremath{\ell}}$ which deviates from the Standard Model prediction by $2\ensuremath{\sigma}$ ($27\ensuremath{\sigma}$) This deviation goes up to $34\ensuremath{\sigma}$ level when the two measurements in the $D$ and ${D}^{*}$ modes are taken together and could indicate new physics Using an effective Lagrangian for the new physics, we study the implication of these results and calculate other observables that can shed light on the nature of the new physics We show that the measurements of the forward-backward asymmetries and the $\ensuremath{\tau}$ and ${D}^{*}$ polarization fractions can be distinguished among the various couplings of the new physics operators

Novel quark smearing for hadrons with high momenta in lattice QCD

Abstract: Hadrons in lattice QCD are usually created employing smeared interpolators. We introduce a new quark smearing that allows us to maintain small statistical errors and good overlaps of hadronic wave functions with the respective ground states, also at high spatial momenta. The method is successfully tested for the pion and the nucleon at a pion mass ${m}_{\ensuremath{\pi}}\ensuremath{\approx}295\text{ }\text{ }\mathrm{MeV}$ and momenta as high as 2.8 GeV. We compare the results obtained to dispersion relations and suggest further optimizations.

Search for new physics in events with same-sign dileptons and jets in pp collisions at √s = 8 TeV

Abstract: A search for new physics is performed based on events with jets and a pair of isolated, same-sign leptons. The results are obtained using a sample of proton-proton collision data collected by the CMS experiment at a centre-of-mass energy of 8 TeV at the LHC, corresponding to an integrated luminosity of 19.5 fb−1. In order to be sensitive to a wide variety of possible signals beyond the standard model, multiple search regions defined by the missing transverse energy, the hadronic energy, the number of jets and b-quark jets, and the transverse momenta of the leptons in the events are considered. No excess above the standard model background expectation is observed and constraints are set on a number of models for new physics, as well as on the same-sign top-quark pair and quadruple-top-quark production cross sections. Information on event selection efficiencies is also provided, so that the results can be used to confront an even broader class of new physics models.

High- T c superconductors: A variational theory of the superconducting state

Abstract: We use a variational approach to gain insight into the strongly correlated $d$-wave superconducting state of the high ${T}_{c}$ cuprates at $T=0$. We show that strong correlations lead to qualitatively different trends in pairing and phase coherence: the pairing scale decreases monotonically with hole doping while the superconducting order parameter shows a nonmonotonic dome. We obtain detailed results for the doping dependence of a large number of experimentally observable quantities, including the chemical potential, coherence length, momentum distribution, nodal quasiparticle weight and dispersion, incoherent features in photoemission spectra, optical spectral weight, and superfluid density. Most of our results are in remarkable quantitative agreement with existing data and some of our predictions, first reported in Phys. Rev. Lett. 87, 217002 (2001), have been recently verified.