相关论文: Axions from wall decay
Recently, axion-like particle search has received renewed interest. In particular, several groups have started ``light shining through a wall'' experiments based on magnetic field and laser both continuous, which is very demanding in terms…
We calculate axion radiation emitted in the collision of two straight global strings. The strings are supposed to be in the unexcited ground state, to be inclined with respect to each other, and to move in parallel planes. Radiation arises…
A mechanism for lifting the cosmological upper bound on the axion decay constant, $f_a$, is proposed. It entails the near masslessness of the radial mode whose vacuum expectation value is $f_a$. Energy in the coherent oscillations of the…
We study the approach to scaling in axion string networks in the radiation era, through measuring the root-mean-square velocity $v$ as well as the scaled mean string separation $x$. We find good evidence for a fixed point in the phase-space…
The current cosmological constraints on a dark matter axion are reviewed. We describe the basic mechanisms by which axions are created in the early universe, both in the standard thermal scenario in which axion strings form and in…
Constraints on the tension and the abundance of cosmic strings depend crucially on the rate at which they decay into particles and gravitational radiation. We study the decay of cosmic string loops in the Abelian-Higgs model by performing…
In theories of axion dark matter with large axion decay constant, temperature variations in the CMB are extremely sensitive to perturbations in the initial axion field, allowing one to place a lower bound on the total amount of inflation.…
We study the evolution of abelian-Higgs string networks in numerical simulations. These are compared against a modified velocity-dependent one scale model for cosmic string network evolution. This incorporates the contributions of loop…
We argue that the QCD axion can arise from many aligned axions with decay constants much smaller than the conventional axion window. If the typical decay constant is of {\cal O}{(100)} GeV to 1 TeV, one or more of the axions or saxions may…
We consider axion cloud decay due to the axion-photon conversion with multi-pole background magnetic fields. We focus on the $\ell=m=1$ and $n=2$ mode for the axion field configuration since it has the largest growth rate associated with…
A favored scenario for axions to be dark matter is for them to form a cosmic string network that subsequently decays, allowing for a tight link between the axion mass and relic abundance. We discuss an example in which the axion is…
The propagation of an action potential is accompanied by mechanical and thermal effects. Several mathematical models explain the deformation of the unmyelinated axon wall. In this paper, the deformation of the myelinated axon wall is…
We introduce a class of unified supersymmetric axion theories with unified and PQ symmetries broken by the same set of fields at a scale $\sim 2\times 10^{16}$ GeV. A typical domain wall number of order 30 leads to an axion decay constant…
We consider an axion cloud around a black hole with background magnetic fields. We calculate the decay rate of the axion cloud due to the axion-photon conversion associated with the axion-photon coupling. For simplicity, we consider the…
If their number density is high enough, clusters of axions can decay to photons via stimulated emission. We study both the special and general relativistic corrections to lasing in such dense axion clusters as they evolve in static…
The rate of energy exchange of spatially localized and gravitationally bound axion configurations with electromagnetic radiation is investigated in presence of strong static magnetic field. Fully analytic treatment is achieved based on…
We consider closed-string tachyon condensation in the twisted sectors on the C/Z_{2n+1} \times R^{7,1} orbifold. We calculate the localized energy density in the fixed plane on the orbifold at the one-loop level, and we obtain the decay…
We propose a scenario where the saxion dominates the energy density of the Universe and reheats the standard model sector via the dilatonic coupling, while its axionic partner contributes to dark matter decaying into photons via the same…
String theories suggest the existence of a plethora of axion-like fields with masses spread over a huge number of decades. Here we show that these ideas lend themselves to a model of quintessence with no super-Planckian field excursions and…
The damping of the axionic string motion due to the surrounding plasma is estimated by a detailed calculation of the fermion scatter from a global string and it is shown that the friction force on the string can be neglected before the…