8,276 research outputs found

    Search for New Physics via Single Top Production at the LHC

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    We consider single-top production as a probe for new physics effects at the Large Hadron Collider (LHC). We argue that for natural theories a small deviation from the Standard Model tree-level couplings in this reaction can be parameterized by 3 higher dimension operators. Precision measurement of these effective couplings in the single-top events, via studying their interference effects with the SM contributions, can discriminate several new physics models. In particular, combining the production rate of three single-top production modes will provide a severe test of the Little Higgs model with T-parity. We find that at the LHC, a 5% accuracy in the measurement of the single-top cross sections would probe the new physics scale up to about 3TeV3 {\rm TeV}.Comment: version to appear in Physics Letters

    Impact of Single-Top Measurement to Littlest Higgs Model with T-Parity

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    We show that a precise measurement of the single-top production cross section at the Tevatron and the LHC can strongly constrain the model parameters of the Littlest Higgs model with T-parity. A reduction in the single-top production rate from the Standard Model prediction implies new physics phenomena generated by the heavy T-parity partners of the top quark. We show that the degree of polarization of the top quark produced from the decay of its heavy T-odd partner (T−T_{-}) can be utilized to determine the new physics energy scale, and the mass of T−T_{-} can be measured from the missing transverse momentum distribution in the T−Tˉ−T_{-}\bar{T}_{-} event

    Tris(tetra­methyl­ammonium) tetra-μ2-sulfido-tetra­sulfidocopper(I)dimolyb­denum(VI) N,N-dimethyl­formamide solvate

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    The title compound, (C4H12N)3[CuMo2S8]·C3H7NO, was obtained from the self-assembly of tetra­thio­molybdate, tetra­methyl­ammonium nitrate and cuprous sulfide in dimethyl­formamide (DMF). The asymmetric unit contains three (NMe4)+ cations, one [Mo2S8Cu]3− anion and one DMF solvent mol­ecule, and no obvious inter­actions are observed between these species. The trinuclear anion can be viewed as fused [MoS4Cu]− units sharing a copper center. The geometric parameters of the trivalent anion are comparable to those reported for other related salts including isomorphous anions, namely (NEt4)2(PPh4)[Mo2S8Cu] (a) and (Ph3P=N=PPh3)2(NEt4)[W2S8Cu]·2CH3CN (b). However, the Mo—Cu—Mo angle is found to be 160.24 (3)° for the title salt, while this angle is 162.97 (2)° in (a) and the W—Cu—W angle is 170.3 (2)° in (b), indicating that the largest deviation from linearity is in the title compound

    Estimating strength of rubberized concrete using evolutionary multivariate adaptive regression splines

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    This study proposes an artificial intelligence (AI) model to predict the compressive strength and splitting tensile strength of rubberized concrete. This Evolutionary Multivariate Adaptive Regression Splines (EMARS) model is a hybrid of the Multivariate Adaptive Regression Splines (MARS) and Artificial Bee Colony (ABC) within which MARS addresses learning and curve fitting and ABC implements optimization to determine the fittest parameter settings with minimal prediction error. K-fold cross validation was utilized to compare EMARS performance against four other benchmark data mining techniques including MARS, Back-propagation Neural Network (BPNN), Radial Basis Function Neural Network (RBFNN), and Genetic Programming (GP). Comparison results showed EMARS to be the best model for predicting rubberized concrete strength and study results demonstrated EMARS as a reliable tool for civil engineers in the concrete construction industry

    Tanshinone IIA mitigates peritoneal fibrosis by inhibiting EMT via regulation of TGF-β/smad pathway

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    Purpose: To explore the effects of tanshinone IIA (T-IIA) on Dianeal-N PD-4 (PDF)-induced expression of fibrogenic cytokines in human peritoneal mesothelial cells (HPMCs), and to elucidate the mechanisms of action involved. Methods: Seven groups of HPMCs were used in the study: control group, PDF group, T-IIA group, LY364947 group, and 2 transforming growth factor-β (TGF-β) groups (TGF-β+ 50 μM T-IIA and TGF-β+ 100 μM T- IIA). The expression levels of mRNA and protein of TGF-β, smad2, smad7, α-smooth muscle actin(α-SMA), fibronectin, collagen І, E-cadherin, N-cadherin, matrix metalloprotein-2(MMP-2), and MMP-9 in the various groups were determined by reverse transcription-polymerase chain reaction (RTPCR) and Western blotting as appropriate. Results: The expressions of α-SMA, fibronectin, collagen І, TGF-β and smad2 were significantly upregulated in HPMCs by PDF treatment, but smad7 was down-regulated, relative to the control group (p < 0.01).These PDF-induced effects were reversed by T-IIA (p < 0.05). Inhibition of TGF-β/smad pathway by LY364947 treatment led to significant decrease in the expressions of fibrosis-related proteins, when compared with PDF group (p < 0.05). TGF-β treatment also produced numerous spindleshaped HPMCs characteristic of epithelial-mesenchymal transition (EMT). However, this morphological transition was alleviated, and the expression levels of EMT-related proteins were significantly downregulated by exposure to the two doses of T-IIA (p < 0.05). Conclusion: Tanshinone IIA inhibits EMT in HPMCs by regulating TGF-β/smad pathway, thus mitigating peritoneal fibrosis. Therefore, T-IIA has promising potential as a new drug for the treatment of peritoneal dialysis (PD)-induced fibrosis. Keywords: Peritoneal dialysis, Peritoneal fibrosis, Tanshinone IIA, Epithelial-mesenchymal transitio
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