1,151 research outputs found
The Dispirited Case of Gauged Dark Matter
We explore the constraints and phenomenology of possibly the simplest
scenario that could account at the same time for the active neutrino masses and
the dark matter in the Universe within a gauged symmetry, namely
right-handed neutrino dark matter. We find that null searches from lepton and
hadron colliders require dark matter with a mass below 900 GeV to annihilate
through a resonance. Additionally, the very strong constraints from high-energy
dilepton searches fully exclude the model for . We further explore the phenomenology in the high mass region
(i.e. masses ) and highlight theoretical
arguments, related to the appearance of a Landau pole or an instability of the
scalar potential, disfavoring large portions of this parameter space.
Collectively, these considerations illustrate that a minimal extension of the
Standard Model via a local symmetry with a viable thermal dark
matter candidate is difficult to achieve without fine-tuning. We conclude by
discussing possible extensions of the model that relieve tension with collider
constraints by reducing the gauge coupling required to produce the correct
relic abundance.Comment: 21 pages, 8 figures. v2: References added. Matches the published
versio
Baryogenesis and Dark Matter from Mesons
We present a new mechanism of Baryogenesis and dark matter production in
which both the dark matter relic abundance and the baryon asymmetry arise from
neutral meson oscillations and subsequent decays. This set-up is testable
at hadron colliders and -factories. In the early Universe, decays of a long
lived particle produce mesons and anti-mesons out of thermal equilibrium.
These mesons/anti-mesons then undergo CP violating oscillations before quickly
decaying into visible and dark sector particles. Dark matter will be charged
under Baryon number so that the visible sector baryon asymmetry is produced
without violating the total baryon number of the Universe. The produced baryon
asymmetry will be directly related to the leptonic charge asymmetry in neutral
decays; an experimental observable. Dark matter is stabilized by an
unbroken discrete symmetry, and proton decay is simply evaded by kinematics. We
will illustrate this mechanism with a model that is unconstrained by di-nucleon
decay, does not require a high reheat temperature, and would have unique
experimental signals -- a positive leptonic asymmetry in meson decays, a
new decay of mesons into a baryon and missing energy, and a new decay of
-flavored baryons into mesons and missing energy. These three observables
are testable at current and upcoming collider experiments, allowing for a
distinct probe of this mechanism.Comment: 17 pages, 6 figures. v2: references added, corrected the antinucleon
abundance calculation (sec III.C.iii), and included comments on the viability
of a measurement of the decay of -flavored baryons into mesons and missing
energy at hadron colliders (sec IV.A.iii). v3: matches the published versio
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