664 research outputs found

    QCD Corrections to Resonant Slepton Production in Hadron Colliders

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    We consider resonant production of sneutrino and slepton at hadronic colliders such as the Tevatron and the LHC within the context of a R-parity violating supersymmetric model. We present next to leading order QCD corrections to total cross sections which originate from both quark- as well as gluon-initiated processes. For couplings involving only the first generation quarks, the K factor at the Tevatron can be as large as 1.5 for a 100 GeV sfermion and falls to nearly 1.1 as the sfermion mass reaches 1 TeV. At the LHC, the variation is between 1.2 and 1.45 for masses less than 2 TeV. While the dependence on the parton density parametrization is found to be mild, this ceases to be true if the strange quark plays a dominant role in the production process. We also study the renormalization and factorization-scale dependence and find it to be less pronounced for the NLO cros sections as compared to the LO. The results obtained in this article are also applicable to resonant production of any color-neutral scalar

    Design and development of FRP mobile fish vending trolley for hygienic fish marketing

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    A mobile fish vending trolley has been designed and developed by Indian Council of Agricultural Research (ICAR) - All India Coordinated Research Project on Plasticulture Engineering and Technology (AICRP on PET) centre at ICAR-Central Institute of Freshwater Aquaculture (ICAR-CIFA), Bhubaneswar to aid the fisher folks for vending their fish harvests in hygienic condition. The unique selling proposition (USP) of the vending unit is its unibody design, where icebox for storing fish, 20 l capacity water storage tank for hand washing, tool box, fish cutting deck and waste collection chambers are integrated into the unit. The icebox can store 100 kg of fish in ice which can be sold in a single day by the fisher folks. The complete unit of mobile fish vending carriage is fabricated with fibre reinforced plastic (FRP), because of its high strength compared to other plastics, ease of fabrication and good insulation property of fiberglass (i.e. thermal conductivity= 0.04 w/mK at normal room temperature 25 ºC). The dimensions of the carriage unit is 4.0’x2’9”x2’6” in which half portion is dedicated for the insulated ice box and the remaining portion houses the fish cutting deck, waste collection chamber and tool box. This fish vending trolley would be a boon for the marginal fish vendors, who want to sell fish in a hygienic condition and to increase income generation potential by selling 100 kg fish in a day

    Noether Current, Horizon Virasoro Algebra and Entropy

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    We provide a simple and straightforward procedure for defining a Virasoro algebra based on the diffeomorphisms near a null surface in a spacetime and obtain the entropy density of the null surface from its central charge. We use the off-shell Noether current corresponding to the diffeomorphism invariance of a gravitational Lagrangian L(gab,Rabcd)L(g_{ab},R_{abcd}) and define the Virasoro algebra from its variation. This allows us to identify the central charge and the zero mode eigenvalue using which we obtain the entropy density of the Killing horizon. Our approach works for all Lanczos-Lovelock models and reproduces the correct Wald entropy. The entire analysis is done off-shell without using the field equations and allows us to define an entropy density for any null surface which acts as a local Rindler horizon for a particular class of observers.Comment: V2: to appear in Phys. Rev.

    Phase transition and scaling behavior of topological charged black holes in Horava-Lifshitz gravity

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    Gravity can be thought as an emergent phenomenon and it has a nice "thermodynamic" structure. In this context, it is then possible to study the thermodynamics without knowing the details of the underlying microscopic degrees of freedom. Here, based on the ordinary thermodynamics, we investigate the phase transition of the static, spherically symmetric charged black hole solution with arbitrary scalar curvature 2k2k in Ho\v{r}ava-Lifshitz gravity at the Lifshitz point z=3z=3. The analysis is done using the canonical ensemble frame work; i.e. the charge is kept fixed. We find (a) for both k=0k=0 and k=1k=1, there is no phase transition, (b) while k=1k=-1 case exhibits the second order phase transition within the {\it physical region} of the black hole. The critical point of second order phase transition is obtained by the divergence of the heat capacity at constant charge. Near the critical point, we find the various critical exponents. It is also observed that they satisfy the usual thermodynamic scaling laws.Comment: Minor corrections, refs. added, to appear in Class. Quant. Grav. arXiv admin note: text overlap with arXiv:1111.0973 by other author

    Hamilton-Jacobi Tunneling Method for Dynamical Horizons in Different Coordinate Gauges

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    Previous work on dynamical black hole instability is further elucidated within the Hamilton-Jacobi method for horizon tunneling and the reconstruction of the classical action by means of the null-expansion method. Everything is based on two natural requirements, namely that the tunneling rate is an observable and therefore it must be based on invariantly defined quantities, and that coordinate systems which do not cover the horizon should not be admitted. These simple observations can help to clarify some ambiguities, like the doubling of the temperature occurring in the static case when using singular coordinates, and the role, if any, of the temporal contribution of the action to the emission rate. The formalism is also applied to FRW cosmological models, where it is observed that it predicts the positivity of the temperature naturally, without further assumptions on the sign of the energy.Comment: Standard Latex document, typos corrected, refined discussion of tunneling picture, subsection 5.1 remove

    Analysis of electron mobility in HfO2/TiN gate metal-oxide-semiconductor field effect transistors: The influence of HfO2 thickness, temperature, and oxide charge

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    We report a new analysis of electron mobility in HfO2/TiN gate metal-oxide-semiconductor field effect transistors (MOSFETs) by investigating the influence of HfO2 thickness (1.6-3 nm), temperature (50-350 K), and oxide charge (similar to 1x10(11)-8x10(12) cm(-2)) in the high inversion charge region. The fixed oxide charge and interface state densities are deliberately increased using negative-bias-temperature stress, allowing the determination of the Coulomb scattering term as a function of temperature for various oxide charge levels. The temperature dependence of the Coulomb scattering term is consistent with the case of a strongly screened Coulomb potential. Using the experimentally determined temperature dependence of Coulomb scattering term, a model is developed for the electron mobility, including the effects oxide charge (mu(C)), high-k phonon (mu(Ph-Hk)), silicon phonon (mu(Ph-Si)), and surface roughness scattering (mu(SR)). The model provides an accurate description of the experimental data for variations in HfO2 thickness, temperature, and oxide charge. Using the model the relative contributions of each mobility component are presented for varying oxide charge and high-k thickness. Scaling of the HfO2 physical thickness provided a reduction in the oxide charge and high-k phonon scattering mechanisms, leading to an increase in electron mobility in HfO2/TiN gate MOSFETs

    Logarithmic Corrections to Schwarzschild and Other Non-extremal Black Hole Entropy in Different Dimensions

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    Euclidean gravity method has been successful in computing logarithmic corrections to extremal black hole entropy in terms of low energy data, and gives results in perfect agreement with the microscopic results in string theory. Motivated by this success we apply Euclidean gravity to compute logarithmic corrections to the entropy of various non-extremal black holes in different dimensions, taking special care of integration over the zero modes and keeping track of the ensemble in which the computation is done. These results provide strong constraint on any ultraviolet completion of the theory if the latter is able to give an independent computation of the entropy of non-extremal black holes from microscopic description. For Schwarzschild black holes in four space-time dimensions the macroscopic result seems to disagree with the existing result in loop quantum gravity.Comment: LaTeX, 40 pages; corrected small typos and added reference

    Quantum corrections and black hole spectroscopy

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    In the work \cite{BRM,RBE}, black hole spectroscopy has been successfully reproduced in the tunneling picture. As a result, the derived entropy spectrum of black hole in different gravity (including Einstein's gravity, Einstein-Gauss-Bonnet gravity and Ho\v{r}ava-Lifshitz gravity) are all evenly spaced, sharing the same forms as Sn=nS_n=n, where physical process is only confined in the semiclassical framework. However, the real physical picture should go beyond the semiclassical approximation. In this case, the physical quantities would undergo higher-order quantum corrections, whose effect on different gravity shares in different forms. Motivated by these facts, in this paper we aim to observe how quantum corrections affect black hole spectroscopy in different gravity. The result shows that, in the presence of higher-order quantum corrections, black hole spectroscopy in different gravity still shares the same form as Sn=nS_n=n, further confirming the entropy quantum is universal in the sense that it is not only independent of black hole parameters, but also independent of higher-order quantum corrections. This is a desiring result for the forthcoming quantum gravity theory.Comment: 14 pages, no figure, use JHEP3.cls. to be published in JHE

    Back reaction, emission spectrum and entropy spectroscopy

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    Recently, an interesting work, which reformulates the tunneling framework to directly produce the Hawking emission spectrum and entropy spectroscopy in the tunneling picture, has been received a broad attention. However, during the emission process, most related observations have not incorporated the effects of back reaction on the background spacetime, whose derivations are therefore not the desiring results for the real physical process. With this point as a central motivation, in this paper we suitably adapt the \emph{reformulated} tunneling framework so that it can well accommodate the effects of back reaction to produce the Hawking emission spectrum and entropy spectroscopy. Consequently, we interestingly find that, when back reaction is considered, the Parikh-Wilczek's outstanding observations that, an isolated radiating black hole has an unitary-evolving emission spectrum that is \emph{not} precisely thermal, but is related to the change of the Bekenstein-Hawking entropy, can also be reproduced in the reformulated tunneling framework, meanwhile the entropy spectrum has the same form as that without inclusion of back reaction, which demonstrates the entropy quantum is \emph{independent} of the effects of back reaction. As our final analysis, we concentrate on the issues of the black hole information, but \emph{unfortunately} find that, even including the effects of back reaction and higher-order quantum corrections, such tunneling formalism can still not provide a mechanism for preserving the black hole information.Comment: 16 pages, no figure, use JHEP3.cls. to be published in JHE

    Spectroscopy of the rotating BTZ black hole via adiabatic invariance

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    According to Bohr-Sommerfeld quantization rule, an equally spaced horizon area spectrum of a static, spherically symmetric black hole was obtained under an adiabatic invariant action. This method can be extended to the rotating black holes. As an example, we apply this method to the rotating BTZ black hole and obtain the quantized spectrum of the horizon area. It is shown that the area spectrum of the rotating BTZ black hole is equally spaced and irrelevant to the rotating parameter, which is consistent with the Bekenstein conjecture. Specifically, the derivation do not need the quasinormal frequencies and the small angular momentum limit.Comment: 6 pages, 0 figures, to appear in Sci China Ser G-Phys Mech Astron. arXiv admin note: text overlap with arXiv:1106.229
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