3,931 research outputs found
e^+e^-\to (h A)\to bbbb in Abelian Extended Supersymmetric Standard Model
We discuss the cross section in an Abelian
extended SM. We work in that minimum of the scalar potential for which Higgs
trilier coupling is greater than the soft mass parameters. We find that
nex-to-lightest Higgs gives the essential contribution to the cross section in
the small mixing angle and leptophobic limit.Comment: 13 pages, 1 postscript figur
One-Loop Effects in Supergravity Models with an Additional U(1)
For an Abelian extended Supergravity model, we investigate some important low
energy parameters: \tan\beta, Z-Z' mixing angle, lightest CP-even Higgs mass
bound, Z' mass, and effective \mu parameter. By integrating the RGE's from
string scale down to the weak scale we constuct the scalar potential, and
analyze the quantities above at the tree- and one-loop levels by including the
contributions of top squarks and top quark in the effective potential. PACS:
04.65.+e, 12.60.JvComment: 16 pages, 6 postscript figure
Q-ball formation in the MSSM with explicit CP violation
Q-balls generically exist in the supersymmetric extensions of the standard
model. Taking into account the additional sources of CP violation, which are
naturally accomodated by the supersymmetric models, it is shown that the Q-ball
matter depends additively on individual CP phases, whereas mass per unit charge
in the Q-ball depends only on the relative phases. There are regions of the
parameter space where there is no stable Q-ball solution in the CP-conserving
limit whereas finite CP phases induce a stable Q-ball.Comment: 6 p
Renormalization Group Invariants in the MSSM and Its Extensions
We derive one-loop renormalization group (RG) invariant observables and
analyze their phenomenological implications in the MSSM and its \mu problem
solving extensions, U(1)' model and NMSSM. We show that there exist several RG
invariants in the gauge, Yukawa and soft-breaking sectors of each model. In
general, RG invariants are highly useful for projecting experimental data to
messenger scale, for revealing correlations among the model parameters, and for
probing the mechanism that breaks supersymmetry. The Yukawa couplings and
trilinear soft terms in U(1)' model and NMSSM do not form RG invariants though
there exist approximate invariants in low tan(beta). In the NMSSM, there are no
invariants that contain the Higgs mass-squareds. We provide a comparative
analysis of RG invariants in all three models and analyze their model-building
and phenomenological implications by a number of case studies.Comment: 32 pages, 5 tables; extended previous analysis to include U(1)'
models and NMSSM where a comparative discussion is give
Bayesian estimation of the transmissivity spatial structure from pumping test data
Estimating the statistical parameters (mean, variance, and integral scale) that define the spatial structure of the transmissivity or hydraulic conductivity fields is a fundamental step for the accurate prediction of subsurface flow and contaminant transport. In practice, the determination of the spatial structure is a challenge because of spatial heterogeneity and data scarcity. In this paper, we describe a novel approach that uses time drawdown data from multiple pumping tests to determine the transmissivity statistical spatial structure. The method builds on the pumping test interpretation procedure of Copty et al. (2011) (Continuous Derivation method, CD), which uses the time-drawdown data and its time derivative to estimate apparent transmissivity values as a function of radial distance from the pumping well. A Bayesian approach is then used to infer the statistical parameters of the transmissivity field by combining prior information about the parameters and the likelihood function expressed in terms of radially-dependent apparent transmissivities determined from pumping tests. A major advantage of the proposed Bayesian approach is that the likelihood function is readily determined from randomly generated multiple realizations of the transmissivity field, without the need to solve the groundwater flow equation. Applying the method to synthetically-generated pumping test data, we demonstrate that, through a relatively simple procedure, information on the spatial structure of the transmissivity may be inferred from pumping tests data. It is also shown that the prior parameter distribution has a significant influence on the estimation procedure, given the non-uniqueness of the estimation procedure. Results also indicate that the reliability of the estimated transmissivity statistical parameters increases with the number of available pumping tests.Peer ReviewedPostprint (author's final draft
Signatures for doubly-charged Higgsinos at colliders
Several supersymmetric models with extended gauge structures predict light
doubly-charged Higgsinos. Their distinctive signature at the large hadron
collider is highlighted by studying their production and decay characteristics.Comment: 3 pages, 4 figures, Latex. Submitted for SUSY 2008 proceeding
The effect of abscisic acid application on root-shoot length and some antioxidant enzyme activities of two different tomato seedlings
In this study, we determined the changes in root-shoot length, chlorophyll and carotenoid contents, and some antioxidant enzyme activities in leaf tissues of two different tomato (Lycopersicon esculentum Mill. cv. Aspendos and Donna) seedlings exposed to exogenous abscisic acid (ABA) 7 day intervals for a period of 28 days. Tomato seedlings were grown under controlled conditions using at seedling industry. When the seedlings had first true leaves, ABA was sprayed at 1, 10, 50 and 100 µM on upper and lower epidermis of plants. While 1 and 10 µM ABA exposure caused increases, 50 and 100 µM ABA exposure caused decreases in root and stem length of both tomato cultivars compared to control. Treatment with all ABA concentrations significantly increased the activities of superoxide dismutase (SOD, E.C. 1.15.1.1), catalase (CAT, E.C. 1.11.1.6) and peroxidase (POD, E.C. 1.11.1.7) enzymes. Root-shoot length and pigment content were positively affected by ABA application for 14 and 21 days but 28 days application caused reductions in both parameters. Results of this study revealed that application of ABA at 1 or 10 µM for 14-21 day have shown beneficial role for tomato seedlings. Additionally, we thought that these seedlings which have higher chlorophyll content and SOD, POD and CAT activity compared to controls, were more resistant against various environmental stresses
Nanoplasmonic surfaces enabling strong surface-normal electric field enhancement
Cataloged from PDF version of article.Conventional two-dimensional (2D) plasmonic arrays provide electric field intensity enhancement in the plane, typically with a surface coverage around 50% in the plan-view. Here, we show nanoplasmonic three-dimensional (3D) surfaces with 100% surface coverage enabling strong surface-normal field enhancement. Experimental measurements are found to agree well with the full electromagnetic solution. Along with the surface-normal localization when using the plasmonic 3D-surface, observed maximum field enhancement is 7.2-fold stronger in the 3D-surface than that of the 2D counterpart structure. 3D-plasmonic nonplanar surfaces provide the ability to generate volumetric field enhancement, possibly useful for enhanced plasmonic coupling and interactions. © 2013 Optical Society of America
Comparative study of CW, nanosecond- and femtosecond-pulsed laser microcutting of AZ31 magnesium alloy stents
Magnesium alloys constitute an interesting solution for cardiovascular stents due to their biocompatibility and biodegradability in human body. Laser microcutting is the industrially accepted method for stent manufacturing. However, the laser-material interaction should be well investigated to control the quality characteristics of the microcutting process that concern the surface roughness, chemical composition, and microstructure of the final device. Despite the recent developments in industrial laser systems, a universal laser source that can be manipulated flexibly in terms of process parameters is far from reality. Therefore, comparative studies are required to demonstrate processing capabilities. In particular, the laser pulse duration is a key factor determining the processing regime. This work approaches the laser microcutting of AZ31 Mg alloy from the perspective of a comparative study to evaluate the machining capabilities in continuous wave (CW), ns- and fs-pulsed regimes. Three industrial grade machining systems were compared to reach a benchmark in machining quality, productivity, and ease of postprocessing. The results confirmed that moving toward the ultrashort pulse domain the machining quality increases, but the need for postprocessing remains. The real advantage of ultrashort pulsed machining was the ease in postprocessing and maintaining geometrical integrity of the stent mesh after chemical etching. Resultantly, the overall production cycle time was shortest for fs-pulsed laser system, despite the fact that CW laser system provided highest cutting speed
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