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.

Study of the inclusive production of charged pions, kaons, and protons in pp collisions at √s = 0.9,2.76 and 7 TeV

Abstract: Spectra of identified charged hadrons are measured in pp collisions at the LHC for sqrt(s) = 0.9, 2.76, and 7 TeV. Charged pions, kaons, and protons in the transverse-momentum range pt approximately 0.1-1.7 GeV and for rapidities abs(y) < 1 are identified via their energy loss in the CMS silicon tracker. The average pt increases rapidly with the mass of the hadron and the event charged-particle multiplicity, independently of the center-of-mass energy. The fully corrected pt spectra and integrated yields are compared to various tunes of the PYTHIA6 and PYTHIA8 event generators.

Search for a light charged Higgs boson in top quark decays in pp collisions at √s = 7 TeV

Abstract: Results are presented on a search for a light charged Higgs boson that can be produced in the decay of the top quark to charged H and b quark and which, in turn, decays into tau and tau neutrino. The analysed data correspond to an integrated luminosity of about 2 inverse femtobarns recorded in proton-proton collisions at sqrt(s) = 7 TeV by the CMS experiment at the LHC. The search is sensitive to the decays of the top quark pairs t anti-t to charged Higgs W b anti-b and t anti-t to charged Higgs b anti-b. Various final states have been studied separately, all requiring presence of a tau lepton from charged Higgs decays, missing transverse energy, and multiple jets. Upper limits on the branching fraction B(t to charged Higgs b) in the range of 2-3% are established for charged Higgs boson masses between 80 and 160 GeV, under the assumption that B(charged Higgs to tau anti-tau neutrino) = 1.

Experimental constraints on the spin and parity of the Z(4430)

Abstract: We report the results of several studies of the Λc+π+π-X final state in continuum e+e- annihilation data collected by the Belle detector. An analysis of angular distributions in Λc(2880)+→Σc(2455)0, ++π+,- decays strongly favors a Λc(2880)+ spin assignment of 52 over 32 or 12. We find evidence for Λc(2880)+→Σc(2520)0,++π+,- decay and measure the ratio of Λc(2880)+ partial widths Γ(Σc(2520)π)/Γ(Σc(2455)π)=0.225±0. 062±0.025. This value favors the Λc(2880)+ spin-parity assignment of 52+ over 52-. We also report the first observation of Λc(2940) +→Σc(2455)0,++π+,- decay and measure Λc(2880)+ and Λc(2940)+ mass and width parameters. These studies are based on a 553fb-1 data sample collected at or near the Υ(4S) resonance at the KEKB collider. © 2007 The American Physical Society.

Study of B-→D**0π-(D**0→D(*)+π-) decays

Abstract: We report the results of a study of charged B decays to the D(+/-)pi(-/+)pi(-/+) and D(*+/-)pi(-/+)pi(-/+) final states using complete D-(*) reconstruction. The contributions of two-body B-->D**pi decays with narrow (j=3/2) and broad (j=1/2) D** states have been determined and the masses and widths of four D** states have been measured. This is the first observation of the broad P-wave D-0*(0) and D'(0)(1) mesons. The analysis is based on a data sample of 65 million B(B) over bar pairs collected in the Belle experiment.

ASTEROSEISMOLOGY OF THE SOLAR ANALOGS 16 Cyg A AND B FROM KEPLER OBSERVATIONS

Abstract: The evolved solar-type stars 16 Cyg A and B have long been studied as solar analogs, yielding a glimpse into the future of our own Sun. The orbital period of the binary system is too long to provide meaningful dynamical constraints on the stellar properties, but asteroseismology can help because the stars are among the brightest in the Kepler field. We present an analysis of three months of nearly uninterrupted photometry of 16 Cyg A and B from the Kepler space telescope. We extract a total of 46 and 41 oscillation frequencies for the two components, respectively, including a clear detection of octupole (l = 3) modes in both stars. We derive the properties of each star independently using the Asteroseismic Modeling Portal, fitting the individual oscillation frequencies and other observational constraints simultaneously. We evaluate the systematic uncertainties from an ensemble of results generated by a variety of stellar evolution codes and fitting methods. The optimal models derived by fitting each component individually yield a common age (t = 6.8 ± 0.4 Gyr) and initial composition (Z i = 0.024 ± 0.002, Y i = 0.25 ± 0.01) within the uncertainties, as expected for the components of a binary system, bolstering our confidence in the reliability of asteroseismic techniques. The longer data sets that will ultimately become available will allow future studies of differential rotation, convection zone depths, and long-term changes due to stellar activity cycles.