1,911 research outputs found

    Fourth SM Family Manifestations at CLIC

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    The latest electroweak precision data allow the existence of additional chiral generations in the standard model. We study prospects of search for the fourth standard model family fermions and quarkonia at e+ee^{+}e^{-} and γγ\gamma \gamma options of CLIC. It is shown that CLIC will be powerfull machine for discovery and investigation of both fourth family leptons and quarkonia. Moreover, the formation of the fourth family quarkonia will give a new opportunity to investigate Higgs boson properties.Comment: 7 pages, 6 Table

    The Fourth SM Family Neutrino at Future Linear Colliders

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    It is known that Flavor Democracy favors the existence of the fourth standard model (SM) family. In order to give nonzero masses for the first three family fermions Flavor Democracy has to be slightly broken. A parametrization for democracy breaking, which gives the correct values for fundamental fermion masses and, at the same time, predicts quark and lepton CKM matrices in a good agreement with the experimental data, is proposed. The pair productions of the fourth SM family Dirac (ν4)(\nu_{4}) and Majorana (N1)(N_{1}) neutrinos at future linear colliders with s=500\sqrt{s}=500 GeV, 1 TeV and 3 TeV are considered. The cross section for the process e+eν4ν4ˉ(N1N1)e^{+}e^{-}\to\nu_{4}\bar {\nu_{4}}(N_{1}N_{1}) and the branching ratios for possible decay modes of the both neutrinos are determined. The decays of the fourth family neutrinos into muon channels (ν4(N1)μ±W)(\nu_{4}(N_{1})\to\mu^{\pm}W^{\mp}) provide cleanest signature at e+ee^{+}e^{-} colliders. Meanwhile, in our parametrization this channel is dominant. WW bosons produced in decays of the fourth family neutrinos will be seen in detector as either di-jets or isolated leptons. As an example we consider the production of 200 GeV mass fourth family neutrinos at s=500\sqrt{s}=500 GeV linear colliders by taking into account di-muon plus four-jet events as signatures.Comment: 16 pages, 3 figures, 10 table

    Kaluza-Klein Mesons in Universal Extra Dimensions

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    In models with universal extra dimensions, the isosinglet Kaluza-Klein (KK) quarks, q^1, have very narrow widths, of O(5-10) MeV, and will thus hadronize. Studies of KK-quarkonia, \bar{q}^1 q^1, show very sharp resonances and dramatic signatures at the Linear Collider. In this Brief Report, we consider the possibility of detecting KK-mesons, \bar{q}^1 q, and show that detection at a Linear Collider is unlikely.Comment: One paragraph regarding KK-meson annihilation added. Version to appear in Physical Review

    Role of Alpha Oscillations During Short Time Memory Task Investigated by Graph Based Partitioning

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    In this study, we investigate the clustering pattern of alpha band (8 Hz - 12 Hz) electroencephalogram (EEG) oscillations obtained from healthy individuals during a short time memory task with 3 different memory loads. The retention period during which subjects were asked to memorize a pattern in a square matrix is analyzed with a graph theoretical approach. The functional coupling among EEG electrodes are quantified via mutual information in the time-frequency plane. A spectral clustering algorithm followed by bootstrapping is used to parcellate memory related circuits and for identifying significant clusters in the brain. The main outcome of the study is that the size of the significant clusters formed by alpha oscillations decreases as the memory load increases. This finding corroborates the active inhibition hypothesis about alpha oscillations

    Solutions for certain classes of Riccati differential equation

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    We derive some analytic closed-form solutions for a class of Riccati equation y'(x)-\lambda_0(x)y(x)\pm y^2(x)=\pm s_0(x), where \lambda_0(x), s_0(x) are C^{\infty}-functions. We show that if \delta_n=\lambda_n s_{n-1}-\lambda_{n-1}s_n=0, where \lambda_{n}= \lambda_{n-1}^\prime+s_{n-1}+\lambda_0\lambda_{n-1} and s_{n}=s_{n-1}^\prime+s_0\lambda_{k-1}, n=1,2,..., then The Riccati equation has a solution given by y(x)=\mp s_{n-1}(x)/\lambda_{n-1}(x). Extension to the generalized Riccati equation y'(x)+P(x)y(x)+Q(x)y^2(x)=R(x) is also investigated.Comment: 10 page
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