198 research outputs found

    Testing Technicolor Models via Top Quark Pair Production in High Energy Photon Collisions

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    Pseudo-Goldstone boson contributions to ttˉt\bar{t} production rates in technicolor models with and without topcolor at the s=0.5and1.5\sqrt{s}=0.5 and 1.5 TeV photon colliders and hadron colliders are reviewed. For reasonable ranges of the parameters, the contributions are large enough to be experimentally observable. Models with topcolor, without topcolor and the MSSM with tanβ1\tan\beta\geq 1 can be experimentally distinguished.Comment: Talk given by H.Y. Zhou at the III International Conference on Hyperons,Charm and Beauty Hadrons,Genova,Italy,June 30-July 3 199

    Associated production of a neutral top-Higgs with a heavy-quark pair in the \gamma\gamma collisions at ILC

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    We have studied the associated production processes of a neutral top-Higgs in the topcolor assisted technicolor model with a pair of heavy quarks in \gamma\gamma collisions at the International Linear Collider (ILC). We find that the cross section for t\bar{t}h_t in \gamma\gamma collisions is at the level of a few fb with the c.m. energy \sqrt{s}=1000 GeV, which is consistent with the results of the cross section of t\bar{t}H in the standard model and the cross section of t\bar{t}h in the minimal supersymmetric standard modeland the little Higgs models. It should be distinct that hundreds of to thousands of h_t per year can be produced at the ILC, this process of \gamma\gamma \to t\bar{t}h_t is really interesting in testing the standard model and searching the signs of technicolor.Comment: 4 pages, 4 figures, some references are adde

    Multiscale Technicolor and the Zbb-bar Vertex

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    We estimate the correction to the Zbb-bar vertex arising from the exchanges of the sideways extended technicolor (ETC) boson and the flavor-diagonal ETC boson in the multiscale walking technicolor model. The obtained result is too large to explain the present data. However, if we introduce a new self- interaction for the top quark to induce the top quark condensate serving as the origin of the large top quark mass, the corrected R_b=Gamma_b/Gamma_h can be consistent with the recent LEP data. The corresponding correction to R_c=Gamma_c/Gamma_h is shown to be negligibly small.Comment: 9-page LaTex fil

    Study of \Lambda - \Lambdabar Oscillation in quantum coherent \Lambda\Lambdabar state by using J/\psi \to \Lambda \bar{\Lambda}$ decay

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    We discuss the possibility of searching for the \Lam - \Lamb oscillations for coherent \Lam\Lamb production in the J/\psi \to \Lam \Lamb decay process. The sensitivity of measurement of \Lam -\Lamb oscillation in the external field at BES-III experiment is considered. These considerations indicate an alternative way to probe the ΔB=2\Delta B =2 amplitude in addition to neutron oscillation experiments. Both coherent and time-dependent information can be used to extract the \Lam-\Lamb oscillation parameter. With one year's luminosity at BES-III, we can set an upper limit of \delta m_{\Lam \Lamb} < 10^{-15} MeV at 90% confidence level, corresponding to about 10610^{-6} s of \Lam-\Lamb oscillation time.Comment: 4 pages, no figure, minor corrections to improve grammar, published in Phys.Rev.D as Rapid Communication

    Study of CP violation in Λc+\Lambda_c^+ decay

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    In this paper, we study CP violation in Λc+BP\Lambda_c^+\to BP and Λc+BV\Lambda_c^+\to BV decays, where B,PB,P and VV denote a light spin-1/2 baryon, pseudoscalar and a vector meson respectively. In these processes the TT odd CP violating triple-product (TP) correlations are examined. The genuine CP violating observables which are composed of the helicity amplitudes occurring in the angular distribution are constructed. Experimentally, by performing a full angular analysis it is shown how one may extract the helicity amplitudes and then obtain the TP asymmetries. We estimate the TP asymmetries in \lam decays to be negligible in the standard model making these processes an excellent place to look for new physics. Taking a two Higgs doublet model, as an example of new physics, we show that large TP asymmetries are possible in these decays. Finally, we discuss how BES-III and Super τ\tau-Charm experiments will be sensitive to these CP violating signals in Λc+\Lambda_c^+ decays.Comment: 7 pages, 2 tables. Journal reference is adde

    Detection of quantitative trait loci affecting haematological traits in swine via genome scanning

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    <p>Abstract</p> <p>Background</p> <p>Haematological traits, which consist of mainly three components: leukocyte traits, erythrocyte traits and platelet traits, play extremely important role in animal immune function and disease resistance. But knowledge of the genetic background controlling variability of these traits is very limited, especially in swine.</p> <p>Results</p> <p>In the present study, 18 haematological traits (7 leukocyte traits, 7 erythrocyte traits and 4 platelet traits) were measured in a pig resource population consisting of 368 purebred piglets of three breeds (Landrace, Large White and Songliao Black Pig), after inoculation with the swine fever vaccine when the pigs were 21 days old. A whole-genome scan of QTL for these traits was performed using 206 microsatellite markers covering all 18 autosomes and the X chromosome. Using variance component analysis based on a linear mixed model and the false discovery rate (FDR) test, 35 QTL with FDR < 0.10 were identified: 3 for the leukocyte traits, 28 for the erythrocyte traits, and 4 for the platelet traits. Of the 35 QTL, 25 were significant at <it>FDR </it>< 0.05 level, including 9 significant at <it>FDR </it>< 0.01 level.</p> <p>Conclusions</p> <p>Very few QTL were previously identified for hematological traits of pigs and never in purebred populations. Most of the QTL detected here, in particular the QTL for the platelet traits, have not been reported before. Our results lay important foundation for identifying the causal genes underlying the hematological trait variations in pigs.</p

    The rare decays BXs,dννˉB \to X_{s,d} \nu \bar \nu and Bs,dl+lB_{s,d} \to l^+l^- in the Multiscale Walking Technicolor Model

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    We calculate the contributions to the rare B-decays, BXs,dννˉB \to X_{s,d} \nu \bar \nu, Bs,dl+lB_{s,d} \to l^+l^- from the unit-charged technipions. Within the considered parameter space we find that: (a) the enhancements to the branching ratios in question can be as large as three orders of magnitude; (b) the ALEPH data of BXsννˉB \to X_s \nu \bar \nu lead to strong mass bounds on mp1m_{p1} and mp8m_{p8}: mp8620,475GeVm_{p8} \geq 620, 475 GeV for FQ=40GeVF_Q=40GeV and mp1=100,400GeVm_{p1}=100, 400 GeV respectively. (c) the CDF data of BsμμˉB_s \to \mu \bar \mu lead to a relatively weak limit: mp8320GeVm_{p8} \geq 320 GeV for FQ=40GeVF_Q=40GeV and mp1=200GeVm_{p1}=200 GeV.Comment: Latex file, 6 pages with 2 ps figure
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