20,497 research outputs found

    Light charged Higgs boson production at the Large Hadron electron Collider

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    We study the production of a light charged Higgs boson at the future Large Hadron electron Collider (LHeC), through the process e−p→νeH−qe^- p \to \nu_e H^- q considering both decay channels H−→bcˉH^- \to b \bar c and H−→τνˉτH^- \to \tau \bar \nu_\tau in the final state. We analyse these processes in the context of the 2-Higgs Doublet Model Type III (2HDM-III) and assess the LHeC sensitivity to such H−H^- signals against a variety of both reducible and irreducible backgrounds. We confirm that prospects for H−H^- detection in the 2HDM-III are excellent assuming standard collider energy and luminosity conditions.Comment: 12 pages, 12 figures. Accepted in Physical Review

    Improvement and analysis of a pseudo random bit generator by means of cellular automata

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    In this paper, we implement a revised pseudo random bit generator based on a rule-90 cellular automaton. For this purpose, we introduce a sequence matrix H_N with the aim of calculating the pseudo random sequences of N bits employing the algorithm related to the automaton backward evolution. In addition, a multifractal structure of the matrix H_N is revealed and quantified according to the multifractal formalism. The latter analysis could help to disentangle what kind of automaton rule is used in the randomization process and therefore it could be useful in cryptanalysis. Moreover, the conditions are found under which this pseudo random generator passes all the statistical tests provided by the National Institute of Standards and Technology (NIST)Comment: 20 pages, 12 figure

    NGC 2782: a merger remnant with young stars in its gaseous tidal tail

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    We have searched for young star-forming regions around the merger remnant NGC 2782. By using GALEX FUV and NUV imaging and HI data we found seven UV sources, located at distances greater than 26 kpc from the center of NGC 2782, and coinciding with its western HI tidal tail. These regions were resolved in several smaller systems when Gemini/GMOS r-band images were used. We compared the observed colors to stellar population synthesis models and we found that these objects have ages of ~1 to 11 Myr and masses ranging from 10^3.9 to 10^4.6 Msun. By using Gemini/GMOS spectroscopic data we confirm memberships and derive high metallicities for three of the young regions in the tail (12+log(O/H)=8.74\pm0.20, 8.81\pm0.20 and 8.78\pm0.20). These metallicities are similar to the value presented by the nuclear region of NGC 2782 and also similar to the value presented for an object located close to the main body of NGC 2782. The high metallicities measured for the star-forming regions in the gaseous tidal tail of NGC 2782 could be explained if they were formed out of highly enriched gas which was once expelled from the center of the merging galaxies when the system collided. An additional possibility is that the tail has been a nursery of a few generations of young stellar systems which ultimately polluted this medium with metals, further enriching the already pre-enriched gas ejected to the tail when the galaxies collided.Comment: 11 pages, 5 figures. Accepted for publication in MNRA

    Raios gama na sobrevivência de plantas de maracujazeiro amarelo inoculadas com Fusarium oxysporum f sp. Passiflorae.

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    A murcha de Fusarium ou fusariose ocorre em diversas regiões produtoras de maracujá amarelo e tem ocasionado grandes danos devido à morte das plantas. A mutagênese associada à seleção in vitro utilizando fitotoxinas possibilita a aplicação de uma pressão de seleção sobre um grande número de propágulos e, assim, pode direcionar a seleção dos mutantes específicos. Neste trabalho, foi analisado o efeito de raios gama sobre a sobrevivência de plantas de maracujazeiro amarelo inoculados com F. oxysporum f. sp. passflorae. Brotações foliares provenientes de segmentos caulinares de P. edulis irradiados a 20Gy foram submetidas a dois ciclos de seleção em meio de cultura suplementado com o filltrado da cultura fúngica (40% e 50% de filtrado). As plantas selecionadas foram inoculadas com a suspensão de conídio em casa de vegetação e após, transferidas para o campo em local com histórico da doença. Ao final da etapa de seleção in vitro, sobreviveram 17,05% das plantas irradiadas e nenhuma planta do tratamento testemunha. A inoculação com a suspensão de conídio não resultou em diferenças significativas na sobrevivência das plantas irradiadas e não irradiadas. No entanto, em condições de campo, foi confirmado o efeito da radiação no aumento da sobrevivência das plantas, sendo verificada a sobrevivência de 77,78% das plantas irradiadas e a morte de todas as plantas do tratamento testemunha

    GHASP: an H{\alpha} kinematic survey of spiral and irregular galaxies -- IX. The NIR, stellar and baryonic Tully-Fisher relations

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    We studied, for the first time, the near infrared, stellar and baryonic Tully-Fisher relations for a sample of field galaxies taken from an homogeneous Fabry-Perot sample of galaxies (the GHASP survey). The main advantage of GHASP over other samples is that maximum rotational velocities were estimated from 2D velocity fields, avoiding assumptions about the inclination and position angle of the galaxies. By combining these data with 2MASS photometry, optical colors, HI masses and different mass-to-light ratio estimators, we found a slope of 4.48\pm0.38 and 3.64\pm0.28 for the stellar and baryonic Tully-Fisher relation, respectively. We found that these values do not change significantly when different mass-to-light ratios recipes were used. We also point out, for the first time, that rising rotation curves as well as asymmetric rotation curves show a larger dispersion in the Tully-Fisher relation than flat ones or than symmetric ones. Using the baryonic mass and the optical radius of galaxies, we found that the surface baryonic mass density is almost constant for all the galaxies of this sample. In this study we also emphasize the presence of a break in the NIR Tully-Fisher relation at M(H,K)\sim-20 and we confirm that late-type galaxies present higher total-to-baryonic mass ratios than early-type spirals, suggesting that supernova feedback is actually an important issue in late-type spirals. Due to the well defined sample selection criteria and the homogeneity of the data analysis, the Tully-Fisher relation for GHASP galaxies can be used as a reference for the study of this relation in other environments and at higher redshifts.Comment: 16 pages, 6 figures. Accepted for publication in MNRA

    Mesoscopic circuits with charge discreteness:quantum transmission lines

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    We propose a quantum Hamiltonian for a transmission line with charge discreteness. The periodic line is composed of an inductance and a capacitance per cell. In every cell the charge operator satisfies a nonlinear equation of motion because of the discreteness of the charge. In the basis of one-energy per site, the spectrum can be calculated explicitly. We consider briefly the incorporation of electrical resistance in the line.Comment: 11 pages. 0 figures. Will be published in Phys.Rev.

    Unsupervised classification and areal measurement of land and water coastal features on the Texas coast

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    Multispectral scanner (MSS) digital data from ERTS-1 was used to delineate coastal land, vegetative, and water features in two portions of the Texas Coastal Zone. Data (Scene ID's 1037-16244 and 1037-16251) acquired on August 29, 1972, were analyzed on NASA Johnson Space Center systems through the use of two clustering algorithms. Seventeen to 30 spectrally homogeneous classes were so defined. Many classes were identified as being pure features such as water masses, salt marsh, beaches, pine, hardwoods, and exposed soil or construction materials. Most classes were identified to be mixtures of the pure class types. Using an objective technique for measuring the percentage of wetland along salt marsh boundaries, an analysis was made of the accuracy of areal measurement of salt marshes. Accuracies ranged from 89 to 99 percent. Aircraft photography was used as the basis for determining the true areal size of salt marshes in the study sites
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