164 research outputs found

    Direct Detection Signals from Absorption of Fermionic Dark Matter

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    We present a new class of direct detection signals; absorption of fermionic dark matter. We enumerate the operators through dimension six which lead to fermionic absorption, study their direct detection prospects, and summarize additional constraints on their suppression scale. Such dark matter is inherently unstable as there is no symmetry which prevents dark matter decays. Nevertheless, we show that fermionic dark matter absorption can be observed in direct detection and neutrino experiments while ensuring consistency with the observed dark matter abundance and required lifetime. For dark matter masses well below the GeV scale, dedicated searches for these signals at current and future experiments can probe orders of magnitude of unexplored parameter space.Comment: 7 pages, 2 figures. v2: published in PRL with minor revisions and changes to Fig 2 (no change to results

    A Predictive Mirror Twin Higgs with Small Z2\mathbf{Z}_2 Breaking

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    The twin Higgs mechanism is a solution to the little hierarchy problem in which the top partner is neutral under the Standard Model (SM) gauge group. The simplest mirror twin Higgs (MTH) model -- where a Z2\mathbf{Z}_2 symmetry copies each SM particle -- has too many relativistic degrees of freedom to be consistent with cosmological observations. We demonstrate that MTH models can have an observationally viable cosmology if the twin mass spectrum leads to twin neutrino decoupling before the SM and twin QCD phase transitions. Our solution requires the twin photon to have a mass of ∼20\sim 20 MeV and kinetically mix with the SM photon to mediate entropy transfer from the twin sector to the SM. This twin photon can be robustly discovered or excluded by future experiments. Additionally, the residual twin degrees of freedom present in the early Universe in this scenario would be detectable by future observations of the cosmic microwave background.Comment: 7+4 pages, 4 figure

    The Exoneration of Job: A Discussion of the Joban and Yahwistic Speeches

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    This study aims to determine whether Job, staunchly established as innocent in the prosaic introduction of the book, maintains his blamelessness throughout the lengthy poetic corpus. The speeches of the dominant characters, Job and Yahweh, will be examined in order to determine whether Job is in the end exonerated by Yahweh\u27s poetic words despite the harsh statements made in the man\u27s own speeches

    Maximizing Direct Detection with Highly Interactive Particle Relic Dark Matter

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    We estimate the maximum direct detection cross section for sub-GeV dark matter (DM) scattering off nucleons. For DM masses in the range 10 keV −100 MeV10 \text{ keV }- 100 \text{ MeV}, cross sections greater than 10−3610^{-36}- 10−30 cm210^{-30} \,\text{cm}^2 seem implausible. We present a DM candidate which realizes this maximum cross section: HighlY interactive ParticlE Relics (HYPERs). After HYPERs freeze-in, a dark sector phase transition decreases the mediator's mass. This increases the HYPER's direct detection cross section without impacting its abundance or measurements of Big Bang Nucleosynthesis and the Cosmic Microwave Background.Comment: 5+3 pages, 3 figures. v2: published in PRL with minor revision

    Charged B mesogenesis

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    We leverage the CP violation in charged B meson decays to generate the observed baryon asymmetry and dark matter at Oð10 MeVÞ temperatures. We realize this in two scenarios: Bþ c mesogenesis and Bþ mesogenesis. In the first, CP-violating Bc decays to B mesons are followed by decays to dark and Standard Model baryons. In the second, CP-violating B decays to lighter charged mesons are accompanied by the latter’s decays to dark and Standard Model leptons, which then scatter into the baryon asymmetry. Bþc mesogenesis is actively being probed at Belle and LHCb, while Bþ mesogenesis can be tested at colliders and sterile neutrino searches

    F-106B airplane active control landing gear drop test performance

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    Aircraft dynamic loads and vibrations resulting from landing impact and from runway and taxiway unevenness are recognized as significant factors in causing fatigue damage, dynamic stress on the airframe, crew and passenger discomfort, and reduction of the pilot's ability to control the aircraft during ground operations. One potential method for improving operational characteristics of aircraft on the ground is the application of active control technology to the landing gears to reduce ground loads applied to the airframe. An experimental investigation was conducted on series-hydraulic active control nose gear. The experiments involved testing the gear in both passive and active control modes. Results of this investigation show that a series-hydraulic active control gear is feasible and that such a gear is effective in reducing the loads transmitted by the gear to the airframe during ground operations

    Resonant Self-Interacting Dark Matter from Dark QCD

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    We present models of resonant self-interacting dark matter in a dark sector with QCD, based on analogies to the meson spectra in Standard Model QCD. For dark mesons made of two light quarks, we present a simple model that realizes resonant self-interaction (analogous to the ϕ\phi-K-K system) and thermal freeze-out. We also consider asymmetric dark matter composed of heavy and light dark quarks to realize a resonant self-interaction (analogous to the Υ(4S)\Upsilon(4S)-B-B system) and discuss the experimental probes of both setups. Finally, we comment on the possible resonant self-interactions already built into SIMP and ELDER mechanisms while making use of lattice results to determine feasibility.Comment: 10 pages, 5 figure
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