157 research outputs found
Dark Matter Induced Nucleon Decay: Model and Signatures
If dark matter (DM) carries anti-baryon number, a DM particle may annihilate
with a nucleon by flipping to anti-DM. Inspired by Hylogenesis models, we
introduce a single component DM model where DM is asymmetric and carries B and
L as -1/2. It can annihilate with a nucleon to an anti-lepton and an anti-DM at
leading order or with an additional meson at sub-leading order. Such signals
may be observed in proton decay experiments. If DM is captured in the Sun, the
DM induced nucleon decay can generate a large flux of anti-neutrinos, which
could be observed in neutrino experiments. Furthermore, the anti-DM particle in
the final state obtains a relatively large momentum (few hundred MeV), and
escapes the Sun. These fast-moving anti-DM particles could also induce
interesting signals in various underground experiments.Comment: Discussion about (g-2) is added. References are updated. Introduction
is expanded. Accepted by JHE
An effective formalism for testing extensions to General Relativity with gravitational waves
The recent direct observation of gravitational waves (GW) from merging black
holes opens up the possibility of exploring the theory of gravity in the strong
regime at an unprecedented level. It is therefore interesting to explore which
extensions to General Relativity (GR) could be detected. We construct an
Effective Field Theory (EFT) satisfying the following requirements. It is
testable with GW observations; it is consistent with other experiments,
including short distance tests of GR; it agrees with widely accepted principles
of physics, such as locality, causality and unitarity; and it does not involve
new light degrees of freedom. The most general theory satisfying these
requirements corresponds to adding to the GR Lagrangian operators constructed
out of powers of the Riemann tensor, suppressed by a scale comparable to the
curvature of the observed merging binaries. The presence of these operators
modifies the gravitational potential between the compact objects, as well as
their effective mass and current quadrupoles, ultimately correcting the
waveform of the emitted GW.Comment: v1: 43+16 pages, 11 figures, 2 tables; v2: minor corrections; v3:
minor corrections, JHEP published versio
Dark photon vortex formation and dynamics
We study the formation and evolution of vortices in dark photon dark
matter and dark photon clouds that arise through black hole superradiance. We
show how the production of both longitudinal mode and transverse mode dark
photon dark matter can lead to the formation of vortices. After vortex
formation, the energy stored in the dark photon dark matter will be transformed
into a large number of vortex strings, eradicating the coherent dark photon
dark matter field. In the case where a dark photon magnetic field is produced,
bundles of vortex strings are formed in a superheated phase transition, and
evolve towards a configuration consisting of many string loops that are
uncorrelated on large scales, analogous to a melting phase transition in
condensed matter. In the process, they dissipate via dark photon and
gravitational wave emission, offering a target for experimental searches.
Vortex strings were also recently shown to form in dark photon superradiance
clouds around black holes, and we discuss the dynamics and observational
consequences of this phenomenon with phenomenologically motivated parameters.
In that case, the string loops ejected from the superradiance cloud, apart from
producing gravitational waves, are also quantised magnetic flux lines and can
be looked for with magnetometers. We discuss the connection between the
dynamics in these scenarios and similar vortex dynamics found in type II
superconductors.Comment: 40 pages, 19 figures, updated to the journal version, with emphasis
on the depletion of dark photon dark matter after vortex formatio
Unified maximally natural supersymmetry
Maximally Natural Supersymmetry, an unusual weak-scale supersymmetric extension of the Standard Model based upon the inherently higher-dimensional mechanism of Scherk-Schwarz supersymmetry breaking (SSSB), possesses remarkably good fine tuning given present LHC limits. Here we construct a version with precision unification: is predicted to by unifying into a 5D theory at a Kaluza-Klein scale of , where SSSB is simultaneously realised. Full unification with is accommodated by extending the 5D theory to a supersymmetric gauge theory on a 6D rectangular orbifold at . TeV-scale states beyond the SM include exotic charged fermions implied by with masses lighter than , and squarks in the mass range , providing distinct signatures and discovery opportunities for LHC run II
A small weak scale from a small cosmological constant
We propose a framework in which Weinberg's anthropic explanation of the
cosmological constant problem also solves the hierarchy problem. The weak scale
is selected by chiral dynamics that controls the stabilization of an extra
dimension. When the Higgs vacuum expectation value is close to a fermion mass
scale, the radius of an extra dimension becomes large, and develops an enhanced
number of vacua available to scan the cosmological constant down to its
observed value. At low energies, the radion necessarily appears as an
unnaturally light scalar, in a range of masses and couplings accessible to
fifth-force searches as well as scalar dark matter searches with atomic clocks
and gravitational-wave detectors. The fermion sector that controls the size of
the extra dimension consists of a pair of electroweak doublets and several
singlets. These leptons satisfy approximate mass relations related to the weak
scale and are accessible to the LHC and future colliders.Comment: 58 pages, 16 figure
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