162 research outputs found
A Predictive Mirror Twin Higgs with Small Breaking
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 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 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
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
We estimate the maximum direct detection cross section for sub-GeV dark
matter (DM) scattering off nucleons. For DM masses in the range , cross sections greater than - 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
F-106B airplane active control landing gear drop test performance
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
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 -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
-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
Asymmetric Dark Matter May Not Be Light
It is often said that asymmetric dark matter is light compared to typical
weakly interacting massive particles. Here we point out a simple scheme with a
neutrino portal and asymmetric dark matter which
may be ''added'' to any standard baryogenesis scenario. The dark sector
contains a copy of the Standard Model gauge group, as well as (at least) one
matter family, Higgs, and right-handed neutrino. After baryogenesis, some
lepton asymmetry is transferred to the dark sector through the neutrino portal
where dark sphalerons convert it into a dark baryon asymmetry. Dark hadrons
form asymmetric dark matter and may be directly detected due to the vector
portal. Surprisingly, even dark anti-neutrons may be directly detected if they
have a sizeable electric dipole moment. The dark photons visibly decay at
current and future experiments which probe complementary parameter space to
dark matter direct detection searches. Exotic Higgs decays are excellent
signals at future Higgs factories.Comment: 8 pages, 3 figure
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