18,362 research outputs found

    Novel Creep-resistant Ferritic Alloy Designed by the Concept of Precipitation Hardening with Two Types of Precipitates

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    Search for the signal of monotop production at the early LHC

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    We investigate the potential of the early LHC to discover the signal of monotops, which can be decay products of some resonances in models such as R-parity violating SUSY or SU(5), etc. We show how to constrain the parameter space of the models by the present data of ZZ boson hadronic decay branching ratio, K0βˆ’K0Λ‰K^0-\bar{K^0} mixing and dijet productions at the LHC. Then, we study the various cuts imposed on the events, reconstructed from the hadronic final states, to suppress backgrounds and increase the significance in detail. And we find that in the hadronic mode the information from the missing transverse energy and reconstructed resonance mass distributions can be used to specify the masses of the resonance and the missing particle. Finally, we study the sensitivities to the parameters at the LHC with s\sqrt{s}=7 TeV and an integrated luminosity of 1fbβˆ’11 {\rm fb}^{-1} in detail. Our results show that the early LHC may detect this signal at 5Οƒ\sigma level for some regions of the parameter space allowed by the current data.Comment: 25 pages, 18 figures, 3 tables, version published in Phys.Rev.

    Searching for double-peak and doubly broken gravitational-wave spectra from Advanced LIGO-Virgo's first three observing runs

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    The current LIGO-Virgo observing run has been pushing the sensitivity limit to touch the stochastic gravitational-wave backgrounds (SGWBs). However, no significant detection has been reported to date for any single dominated source of SGWBs with a single broken-power-law (BPL) spectrum. Nevertheless, it could equally well escape from existing Bayesian searches from, for example, two comparable dominated sources with two separate BPL spectra (double-peak case) or a single source with its power-law behavior in the spectrum broken twice (doubly broken case). In this paper, we put constraints on these two cases but specifically for the model with cosmological first-order phase transitions from Advanced LIGO-Virgo's first three observing runs. We found strong negative evidence for the double-peak case and hence place 95\% C.L. upper limits Ξ©BPL,1<5.8Γ—10βˆ’8\Omega_\mathrm{BPL,1}<5.8\times10^{-8} and Ξ©BPL,2<4.4Γ—10βˆ’8\Omega_\mathrm{BPL,2}<4.4\times10^{-8} on the two BPL spectra amplitudes with respect to the unresolved compact binary coalescence (CBC) amplitude Ξ©CBC<5.6Γ—10βˆ’9\Omega_\mathrm{CBC}<5.6\times10^{-9}. We further found weak negative evidence for the doubly broken case and hence place 95\% C.L. upper limit Ξ©DB<1.2Γ—10βˆ’7\Omega_\mathrm{DB}<1.2\times10^{-7} on the overall amplitude of the doubly broken spectrum with respect to Ξ©CBC<6.0Γ—10βˆ’9\Omega_\mathrm{CBC}<6.0\times10^{-9}. In particular, the results from the double-peak case have marginally ruled out the strong super-cooling first-order phase transitions at LIGO-Virgo band.Comment: v1, 5 pages + references, 5 figures, 1 table; v2, 11 pages, 6 figures, 1 table, version accepted for publication in Physical Review D; v3, to match the published versio
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