61 research outputs found

    Top-quark FCNC Productions at LHC in Topcolor-assisted Technicolor Model

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    We evaluate the top-quark FCNC productions induced by the topcolor assisted technicolor (TC2) model at the LHC. These productions proceed respectively through the parton-level processes g g -> t c_bar, c g->t, c g -> t g, c g -> t Z and c g -> t \gamma. We show the dependence of the production rates on the relevant TC2 parameters and compare the results with the predictions in the minimal supersymmetric model. We find that for each channel the TC2 model predicts a much larger production rate than the supersymmetric model. All these rare productions in the TC2 model can be enhanced above the 3-sigma sensitivity of the LHC. Since in the minimal supersymmetric model only c g -> t is slightly larger than the corresponding LHC sensitivity, the observation of these processes will favor the TC2 model over the supersymmetric model. In case of unobservation, the LHC can set meaningful constraints on the TC2 parameters.Comment: 5 pages, 4 fig

    Spectrum for Heavy Quankonia and Mixture of the Relevant Wave Functions within the Framework of Bethe-Salpeter Equation

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    Considering the fact that some excited states of the heavy quarkonia (charmonium and bottomonium) still missing in experimental observations and potential applications of the relevant wave functions of the bound states, we re-analyze the spectrum and the relevant wave functions of the heavy quarkonia within the framework of Bethe-Salpeter (B.S.) equation with a proper QCD-inspired kernel. Such a kernel for the heavy quarkonia, relating to potential of non-relativistic quark model, is instantaneous, so we call the corresponding B.S. equation as BS-In equation throughout the paper. Particularly, a new way to solve the B.S. equation, which is different from the traditional ones, is proposed here, and with it not only the known spectrum for the heavy quarkonia is re-generated, but also an important issue is brought in, i.e., the obtained solutions of the equation `automatically' include the 'fine', 'hyperfine' splittings and the wave function mixture, such as S−DS-D wave mixing in JPC=1−−J^{PC}=1^{--} states, P−FP-F wave mixing in JPC=2++J^{PC}=2^{++} states for charmonium and bottomonium etc. It is pointed out that the best place to test the wave mixture probably is at ZZ-factory (e+e−e^+e^- collider running at ZZ-boson pole with extremely high luminosity).Comment: 26 pages, 8 figure

    Topcolor assisted technicolor models and muon anomalous magnetic moment

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    We discuss and estimate the contributions of the new particles predicted by topcolor assisted technicolor(TC2) models to the muon anomalous magnetic moment aμa_{\mu}. Our results show that the contributions of Pseudo Goldstone bosons are very small which can be safely ignored. The main contributions come from the ETC gauge boson xμx_{\mu} and topcolor gauge boson Z′Z^{\prime}. If we demand that the mass of Z′Z^{\prime} is consistent with other experimental constrains, its contributions are smaller than that of xμx_{\mu}. With reasonable values of the parameters in TC2 models, the observed BNL results for aμa_{\mu} could be explained.Comment: latex file, 11 pages, several figures and references adde

    Climatic warming in China during 1901-2015 based on an extended dataset of instrumental temperature records

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    Monthly mean instrumental surface air temperature (SAT) observations back to the nineteenth century in China are synthesized from different sources via specific quality-control, interpolation, and homogenization. Compared with the first homogenized long-term SAT dataset for China by Cao et al. (2013), which contained 18 stations mainly located in the middle and eastern part of China, the present dataset includes homogenized monthly SAT series at 32 stations, with an extended coverage especially towards western China. Missing values are interpolated by using observations at nearby stations including those from neighboring countries. Cross validation shows that the mean bias error (MBE) is generally small and falls between 0.45°C and -0.35°C. Multiple homogenization methods and available metadata are applied to assess the consistency of the time series and to adjust inhomogeneity biases. The homogenized annual mean SAT series show a range of trends between 1.1 and 4.0°C/century in northeastern China, between 0.4 and 1.9°C/century in southeastern China, and between 1.4 and 3.7°C/century in western China to the west of 105E (from the beginning years of the stations to 2015). The unadjusted data include unusually warm records during the 1940s and hence tend to underestimate the warming trends at a number of stations. The mean SAT series for China based on the Climate Anomaly Method shows a warming trend of 1.56°C/century during 1901-2015, larger than those based on other currently available datasets

    Production and decay of the neutral top-pion in high energy e+e−e^{+}e^{-} colliders

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    We study the production and decay of the neutral top-pion πt0\pi_{t}^{0} predicted by topcolor-assisted technicolor(TC2) theory. Our results show that, except the dominant decay modes bbˉb\bar{b}, tˉc\bar{t}c and gggg, the πt0\pi_{t}^{0} can also decay into γγ\gamma\gamma and ZγZ \gamma modes. It can be significantly produced at high energy e+e−e^{+}e^{-} collider(LC) experiments via the processes e+e−→πt0γe^{+}e^{-}\to \pi_{t}^{0}\gamma and e+e−→Zπt0e^{+}e^{-}\to Z\pi_{t}^{0}. We further calculate the production cross sections of the processes e+e−→γπt0→γtˉce^{+}e^{-}\to\gamma\pi_{t}^{0}\to\gamma\bar{t}c and e+e−→Zπt0→Ztˉce^{+}e^{-}\to Z\pi_{t}^{0}\to Z\bar{t}c. We find that the signatures of the neutral top-pion πt0\pi_{t}^{0} can be detected via these processes.Comment: Latex file, 13 Pages, 6 eps figures. to be published in Phys.Rev.

    Genome sequence of the cultivated cotton <i>Gossypium arboreum</i>

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    The complex allotetraploid nature of the cotton genome (AADD; 2n = 52) makes genetic, genomic and functional analyses extremely challenging. Here we sequenced and assembled the Gossypium arboreum (AA; 2n = 26) genome, a putative contributor of the A subgenome. A total of 193.6 Gb of clean sequence covering the genome by 112.6-fold was obtained by paired-end sequencing. We further anchored and oriented 90.4% of the assembly on 13 pseudochromosomes and found that 68.5% of the genome is occupied by repetitive DNA sequences. We predicted 41,330 protein-coding genes in G. arboreum. Two whole-genome duplications were shared by G. arboreum and Gossypium raimondii before speciation. Insertions of long terminal repeats in the past 5 million years are responsible for the twofold difference in the sizes of these genomes. Comparative transcriptome studies showed the key role of the nucleotide binding site (NBS)-encoding gene family in resistance to Verticillium dahliae and the involvement of ethylene in the development of cotton fiber cells.Genetics &amp; HereditySCI(E)[email protected]; [email protected]; [email protected]

    Ratio-Based Analysis of Differential mRNA Processing and Expression of a Polyadenylation Factor Mutant pcfs4 Using Arabidopsis Tiling Microarray

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    US National Institutes of Health [1R15GM07719201A1]; US National Science Foundation [IOS-0817818]; Ohio Plant Biotech Consortium; National Natural Science Foundation of China [60774033]; Specialized Research Fund for the Doctoral Program of Higher EducatiBackground: Alternative polyadenylation as a mechanism in gene expression regulation has been widely recognized in recent years. Arabidopsis polyadenylation factor PCFS4 was shown to function in leaf development and in flowering time control. The function of PCFS4 in controlling flowering time was correlated with the alternative polyadenylation of FCA, a flowering time regulator. However, genetic evidence suggested additional targets of PCFS4 that may mediate its function in both flowering time and leaf development. Methodology/Principal Findings: To identify further targets, we investigated the whole transcriptome of a PCFS4 mutant using Affymetrix Arabidopsis genomic tiling 1.0R array and developed a data analysis pipeline, termed RADPRE (Ratio-based Analysis of Differential mRNA Processing and Expression). In RADPRE, ratios of normalized probe intensities between wild type Columbia and a pcfs4 mutant were first generated. By doing so, one of the major problems of tiling array data-variations caused by differential probe affinity-was significantly alleviated. With the probe ratios as inputs, a hierarchy of statistical tests was carried out to identify differentially processed genes (DPG) and differentially expressed genes (DEG). The false discovery rate (FDR) of this analysis was estimated by using the balanced random combinations of Col/pcfs4 and pcfs4/Col ratios as inputs. Gene Ontology (GO) analysis of the DPGs and DEGs revealed potential new roles of PCFS4 in stress responses besides flowering time regulation. Conclusion/Significance: We identified 68 DPGs and 114 DEGs with FDR at 1% and 2%, respectively. Most of the 68 DPGs were subjected to alternative polyadenylation, splicing or transcription initiation. Quantitative PCR analysis of a set of DPGs confirmed that most of these genes were truly differentially processed in pcfs4 mutant plants. The enriched GO term "regulation of flower development'' among PCFS4 targets further indicated the efficacy of the RADPRE pipeline. This simple but effective program is available upon request
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