1,365 research outputs found

    Search for Narrow-Width ttbar Resonances in ppbar Collisions at center of mass energy = 1.8 TeV

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    We present a preliminary result on a search for narrow-width resonances that decay into ttbar pairs using 130 pb^{-1} of lepton plus jets data in ppbar collisions at center of mass energy = 1.8 TeV. No significant deviation from Standard Model prediction is observed. 95% C.L. upper limits on the production cross section of the narrow-width resonance times its branching fraction to ttbar are presented for different resonance masses, M_X. We also exclude the existence of a leptophobic topcolor particle, X, with M_X < 560 GeV/c^2 for a width \Gamma_X = 0.012 M_X.Comment: 3 pages, 1 figure; Submitted for proceedings of 5th International Conference on Quark Confinement and Hadron spectrum, held in Italy, from 11-14 Sep., 200

    Effects of neutrino mass hierarchies on dynamical dark energy models

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    We investigate how three different possibilities of neutrino mass hierarchies, namely normal, inverted, and degenerate, can affect the observational constraints on three well known dynamical dark energy models, namely the Chevallier-Polarski-Linder, logarithmic, and the Jassal-Bagla-Padmanabhan parametrizations. In order to impose the observational constraints on the models, we performed a robust analysis using Planck 2015 temperature and polarization data, Supernovae type Ia from Joint Light curve analysis, baryon acoustic oscillations distance measurements, redshift space distortion characterized by f(z)σ8(z)f(z)\sigma_8(z) data, weak gravitational lensing data from Canada-France-Hawaii Telescope Lensing Survey, and cosmic chronometers data plus the local value of the Hubble parameter. We find that different neutrino mass hierarchies return similar fit on almost all model parameters and mildly change the dynamical dark energy properties.Comment: 10 pages, 5 captioned figures, 4 tables; Published version in Phys. Rev.

    Observational Constraints on f(T)f(T) gravity from varying fundamental constants

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    We use observations related to the variation of fundamental constants, in order to impose constraints on the viable and most used f(T)f(T) gravity models. In particular, for the fine-structure constant we use direct measurements obtained by different spectrographic methods, while for the effective Newton's constant we use a model-dependent reconstruction, using direct observational Hubble parameter data, in order to investigate its temporal evolution. We consider two f(T)f(T) models and we quantify their deviation from Λ\LambdaCDM cosmology through a sole parameter. Our analysis reveals that this parameter can be slightly different from its Λ\LambdaCDM value, however the best-fit value is very close to the Λ\LambdaCDM one. Hence, f(T)f(T) gravity is consistent with observations, nevertheless, as every modified gravity, it may exhibit only small deviations from Λ\LambdaCDM cosmology, a feature that must be taken into account in any f(T)f(T) model-building.Comment: 9 pages, 6 figures, 3 Tables, version published in Eur.Phys.J.

    Renewable Energy Options among Rural Households in Haryana and Himachal Pradesh: An Overview

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    In developing countries the energy problems are both widespread and serious. Lack of access to sufficient and sustainable supplies of energy impacts around 90% of the population of many developing countries. People are compelled to live without regular and good quality electricity supply. The rural population remains dependent on fuels such as animal dung, crop residues, fuel wood and charcoal to cook their daily meals. Without efficient, clean energy, people are undermined in their efforts to engage effectively in productive activities and improve their quality of life (Barnes and Floor, 1996). India is home to the largest rural population in the world with approx. 68.84% of the total population residing in rural areas (Census, 2011). In order to contribute to the overall development in India, access to modern energy and cleaner fuel for rural households is important. There is a need to bridge the access gap by expanding energy systems to meet the energy requirements of the fast growing population and mitigate the threat of climate change. The best possible solution to the energy poverty challenges lies in the shift towards sustainable energy technologies. In the present scenario, the uncontrollable increase in use of non-renewable energies such as fossil fuel, oil, natural gas has led to fluctuation of demand and supply. This negative energy balance for decades has forced India to purchase energy from other countries to fulfill the needs of the entire country. Hence, energy access is an important component of poverty alleviation and an indispensable element of sustainable human development. Government of India has initiated numerous development programmes, focusing on providing sustainable energy solutions to rural communities often deprived of clean and uninterrupted energy supply for their daily energy requirements. The study entitled ‘Renewable Energy Options among Rural Households\u27 was conducted in Haryana and Himachal Pradesh states. The outcomes of the study provide a roadmap for future programmes promoting the use of clean, efficient and modern energy technologies, to be implemented more effectively. Findings would further benefit the primary and secondary key stakeholders involved in research and development, formulation of policies and regulations, promoting sale and purchase and provide financial assistance to future energy programmes meant to popularize the use of Renewable Energy Technologies
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