31,923 research outputs found

    Semiparametric Additive Transformation Model under Current Status Data

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    We consider the efficient estimation of the semiparametric additive transformation model with current status data. A wide range of survival models and econometric models can be incorporated into this general transformation framework. We apply the B-spline approach to simultaneously estimate the linear regression vector, the nondecreasing transformation function, and a set of nonparametric regression functions. We show that the parametric estimate is semiparametric efficient in the presence of multiple nonparametric nuisance functions. An explicit consistent B-spline estimate of the asymptotic variance is also provided. All nonparametric estimates are smooth, and shown to be uniformly consistent and have faster than cubic rate of convergence. Interestingly, we observe the convergence rate interfere phenomenon, i.e., the convergence rates of B-spline estimators are all slowed down to equal the slowest one. The constrained optimization is not required in our implementation. Numerical results are used to illustrate the finite sample performance of the proposed estimators.Comment: 32 pages, 5 figure

    The production of neutral Nβˆ—(11052)N^*(11052) resonance with hidden beauty from Ο€βˆ’p\pi^-p scattering

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    We investigate the discovery potential of the predicted neutral hidden beauty Nβˆ—(11052)N^*(11052) resonance through Ο€βˆ’p\pi^- p scattering within an effective Lagrangian approach. Two reactions Ο€βˆ’pβ†’Kβˆ’Ξ£+\pi^-p\rightarrow K^-\Sigma^+ and Ο€βˆ’pβ†’Ξ·bn\pi^-p\rightarrow \eta_bn are studied in this work, with nucleon pole exchange as the background. It is found that the contributions of the Nβˆ—(11052)N^*(11052) resonance give clear peak structures in the magnitude of 1 ΞΌb\mu b near the threshold of the Nβˆ—(11052)N^*(11052) in the total cross sections. The numerical results indicate that the center of mass energy W≃W\simeq 11-11.1 GeV would be a best energy window for searching the Nβˆ—(11052)N^*(11052) resonance, where the Nβˆ—(11052)N^*(11052) signal can be easily distinguished from the background. The COMPASS experiment at CERN's Super Proton Synchrotron (SPS) with pion beam of ≃\simeq 280 GeV will be an ideal platform for searching the super-heavy resonance with hidden beauty, which is hopeful to test the theoretical results

    Multi-kink topological terms and charge-binding domain-wall condensation induced symmetry-protected topological states: Beyond Chern-Simons/BF theory

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    Quantum-disordering a discrete-symmetry breaking state by condensing domain-walls can lead to a trivial symmetric insulator state. In this work, we show that if we bind a 1D representation of the symmetry (such as a charge) to the intersection point of several domain walls, condensing such modified domain-walls can lead to a non-trivial symmetry-protected topological (SPT) state. This result is obtained by showing that the modified domain-wall condensed state has a non-trivial SPT invariant -- the symmetry-twist dependent partition function. We propose two different kinds of field theories that can describe the above mentioned SPT states. The first one is a Ginzburg-Landau-type non-linear sigma model theory, but with an additional multi-kink domain-wall topological term. Such theory has an anomalous Uk(1)U^k(1) symmetry but an anomaly-free ZNkZ_N^k symmetry. The second one is a gauge theory, which is beyond Abelian Chern-Simons/BF gauge theories. We argue that the two field theories are equivalent at low energies. After coupling to the symmetry twists, both theories produce the desired SPT invariant.Comment: 22 pages, 8 figures, symmetry transformaition for the Ginzburg-Landau NLσ\sigmaM is added in the introduction part, references adde
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