198 research outputs found

    Using Jet Substructure at the LHC to Search for the Light Higgs Bosons of the CP-Violating MSSM

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    The CP-violating version of the Minimal Supersymmetric Standard Model (MSSM) is an example of a model where experimental data do not preclude the presence of light Higgs bosons in the range around 10 -- 110 GeV. Such light Higgs bosons, decaying almost wholly to b-bbar pairs, may be copiously produced at the LHC, but would remain inaccessible to conventional Higgs searches because of intractable QCD backgrounds. We demonstrate that a significant number of these light Higgs bosons would be boosted strongly enough for the pair of daughter bb-jet pairs to appear as a single `fat' jet with substructure. Tagging such jets could extend the discovery potential at the LHC into the hitherto-inaccessible region for light Higgs bosons.Comment: LaTeX, 33 pages, 5 eps figures and 5 tables embedded. minor changes, to appear in Physical Review

    EPR study of the Jahn-Teller effect of Cu2+ in ZnTiF6·6H20

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    The 34-GHz EPR spectrum of Cu2+ in ZnTiF6·6H20 shows a Jahn-Teller effect with a transition from a single-line spectrum at high temperatures to a multiline anisotropic spectrum. The transition temperature on cooling varied with Cu concentration from 172 K for a sample containing 0.2 at.% Cu to roughly 90 K for a 46-at. % Cu sample. For dilute samples, the single-line spectrum was isotropic at 300 K with g =2.223±0.005, but showed axial symmetry about the trigonal axis at 180 K with gj1 =2.226±0.005 and g~ =2.223±0.005. At 4.2 K, a "static" Jahn-Teller effect was observed with six axially symmetric Cu2+ spectra, each with g 11 =2.470±0.005, g1 =2.100±0.005, I A 11 I ~ I 06 X 10- 4 em -I, and I A 1 I ~30 X 10- 4 em - I. The z axis of these spectra was found to lie along the fourfold axes of two cubes with a common [Ill] axis, rotated by 40"±2" with respect to each other about this axis. Analysis of the 4.2-K data leads to the values q~O. 50 for the Ham reduction factor and K~O. 26 for the Fenni contact parameter, with A uA 1 < 0. An activation energy of about 100 cm-1 was deduced from the gradual increase of the anisotropy of the spectrum on cooling in the low-temperature region

    A mathematical model for improving the mechanism of satellite antenna

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    The functionality of any type of antenna could be traced to the Maxwell's electromagnetic field equations. However,salient operational problems of antennas are traced back to the Maxwell's. The inclusion of the effects of particulate to either transmission or reception unit of antenna is paramount. The Schrodinger was used to model a now reformed Maxwell's equation which explains in details the electrostatic and induced magnetic field of either transmitting or receiving antenna. This theory applies to only to stationary satellite antennas

    Jahn-Teller EPA spectra of Cu2 + in MgSif6.6H20

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    The 34 GHz EPR spectrum ofCu2+ in MgSiF6-6H20 showed a "static" Jahn-Teller effect at 4.2 K with two inequivalent Jahn- Teller sites per unit cell. The six axially symmetric sets of Cu2+ lines had their z axes parallel to the three tetragonal axes of two cubes, which were rotated by approximately 40" with respect to each other about a common (Ill) axis, which is the crystal c axis. The measured spin-Hamiltonian parameters at 4.2 K for each set of lines were g11 = 2.47 ± 0.01, g1 = 2.10 ± 0.01 , and lA 11 1 = (110 ± 3)X 10- 4 em- •. There was a gradual decrease in the anisotropy of the spectrum on warming the crystal, with a single, nearly isotropic line being observed above 220 K. At 270 K the spectrum had axial symmetry about the c axis with Kn = 2.23 ± 0.01 and g~ = 2.25 ± 0.01 . The temperature evolution of the spectrum was interpreted in terms of a Boltzmann distribution over inequivalent distorted Jahn-Teller configurations, with one potential well lowered by an amount L1:::::: I 05 em- 1 below the other two

    Assessment of wetland change dynamics of Chennai coast, Tamil Nadu, India, using satellite remote sensing

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    1258-1266The coastal wetlands of Chennai are increasingly being affected by anthropogenic factors, such as urbanization, residential, and industrial development. This study helps to monitor and map the dynamics of the coastal wetlands of Chennai using Landsat satellite images of 1988, 1996, 2006, and 2016 by following a supervised classification method. Post-classification wetland change detection was done in three temporal phases, that is, 1988 1996, 1996 2006, and 2006 2016. Change detection matrix analysis was performed to identify the from to changes. Ground truthing was carried out to validate the wetland classes. The overall accuracy of the classified image was 79.29% and the kappa coefficient was 0.7600. These results were imported into a GIS environment for further analysis. It was found that the wetlands have decreased to an alarming extent in the past 28 years from 23.14% in 1988 to 15.79% in 2016 of the total study area, owing to conversion of wetlands into industrial development, urban expansion, and other developmental activities

    Observation of the cubic-field splitting of an excited S = 2 manifold in a cubic copper tetramer

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    EPR measurements on single crystals of Cu40Cl6(triphenylphosphine oxide)4 at liquid helium temperatures in the frequency ranges 14-17 and 34-35 GHz were fitted to a simple cubicS= 2 spin Hamiltonian with g = 2.10 ± 0.01 and a zero-field splitting of(0.53 ± 0.01) em - 1 • From the decrease in intensity of the S = 2 spectrum on cooling below 4.2 K and the absence of an S = 1 spectrum, the S = 2 manifold was deduced to lie ( 14 ± 1) em- 1 above a nonmagnetic ground state. The EPR results are used as a test of the various theories developed to explain the magnetic susceptibility of copper tetramer

    The phase transition temperature at 145 K in cadmium calcium acetat hexahydrate as a function of Cu2+ probe concentration

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    The temperature of the structural phase transition in cadmium calcium acetate hexahydrate as a function of Cu2+ concentration has been studied with electron paramagnetic resonance (EPR). The phase transition temperature was found to vary from 144 to 124 K as the amount of copper varied from 0.07% to 1.3% of the sample weight. An extrapolation of this data predicts a structural phase transition at 145 Kin pure cadmium calcium acetate hexahydrate. Good fits of the data to second-order phase transition theory was obtained with critical exponents close to 0.30

    Neutrino masses along with fermion mass hierarchy

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    Recently a new mechanism has been proposed to cure the problem of fermion mass hierarchy in the Standard Model (SM) model. In this scenario, all SM charged fermions other than top quark arise from higher dimensional operators involving the SM Higgs field. This model also predicted some interesting phenomenology of the Higgs boson. We generalize this model to accommodate neutrino masses (Dirac & Majorana) and also obtain the mixing pattern in the leptonic sector. To generate neutrino masses, we add extra three right handed neutrinos (NiR)(N_{iR}) in this model.Comment: 20 pages, the content on results and phenomenology have been expanded, a new section on UV completion of the model has been added and also some new references, this version has been accepted by Physical Review

    Fishery resources of spiny lobsters in the Andaman Island, India

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    The Andaman and Nicobar (A&N) Islands is the largest archipelago in the Bay of Bengal. In spite of availability of diverse lobster resources, there is no organised lobster fishing in the Islands. The main objective of the study was to collect baseline data on the lobster resources of the Andaman Island. Periodic field surveys were carried out at 33 landing centres in the Andaman and data were collected by direct observation and questionnaires. Mechanised and non-mechanised fishing crafts are engaged in lobster fishing in the Island. Lobsters are manually caught by spears, gillnet, shoreseine and handpicking. Six commercially important species of spiny lobsters, Panulirus penicillatus, P. versicolor, P. homarus, P. ornatus, P. polyphagus and P. longipes are present in the island. Among them, P. penicillatus dominated the landings throughout the study period (1999-2000), with maximum catch in January, followed by P. versicolor. The total lobster landings in Andaman during the study period were estimated as 3.16 tonnes with maximum landings in south Andaman (Port Blair)

    Higgs pair production in association with a vector boson at e+e- colliders in theories of higher dimensional gravity

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    The models of large extra compact dimensions, as suggested by Arkani-Hamed, Dimopoulos and Dvali, predict exciting phenomenological consequences with gravitational interactions becoming strong at the TeV scale. Such theories can be tested at the existing and future colliders. In this paper, we study the contribution of virtual Kaluza-Klein excitations (both spin-0 and 2) in the process e+eHHZe^+e^- \to HHZ and e+eHHγ e^+e^- \to HH\gamma at future linear collider (NLC). We find that the virtual exchange KK gravitons can modify the cross-section σ(e+eHHZ)\sigma(e^+e^- \to HHZ) significantly from its Standard Model value and will allow the effective string scale to be probed up to 6.6 TeV. The second process is absent at the tree level in the standard model, and can therefore be used to put limits on the effective string scale of 7.4 TeV.Comment: One new reference is added, some minor corrections, version to appear in Physical Review
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