相关论文: Astrophysical Bounds on Milli-Charged Particles in…
We update the bounds on fermions with electric charge $\epsilon e$ and mass $m_\epsilon$. For $m_\epsilon\lsim m_e$ we find $10^{-15}\lsim\epsilon<1$ is excluded by laboratory experiments, astrophysics and cosmology. For larger masses, the…
Particles with millicharge q and sub-eV mass can be produced in photon-photon collisions, distorting the energy spectrum of the Cosmic Microwave Background. We derive the conservative bound q < 10^-7 e (as well as model-dependent bounds two…
If Lorentz violation exists, it will affect the thresholds for pair creation processes. Lorentz-violating operators that change the maximum velocities of charged particles may increase or decrease the extinction rate of gamma-rays moving…
We have constrained the charge-mass ($\varepsilon-m$) phase space of millicharged particles through the simulation of the rotational evolution of neutron stars, where an extra slow-down effect due to the accretions of millicharged dark…
We have arrived at tight constraints on the photon charge, giving comparable bounds, one based on the dominance by dark energy at the present epoch, and the other based on the requirement that early universe nucleosynthesis not be affected…
We consider the constraints from Supernova 1987A on particles with small couplings to the Standard Model. We discuss a model with a fermion coupled to a dark photon, with various mass relations in the dark sector; millicharged particles;…
We use the isotropy of the Cosmic Microwave Background to place stringent constraints on a possible electrical charge asymmetry of the universe. We find the excess charge per baryon to be $q_{e-p}<10^{-26}e$ in the case of a uniform…
A lower bound on the light neutrino mass $m_\nu$ is derived in the framework of a geometrical interpretation of quantum mechanics. Using this model and the time of flight delay data for neutrinos coming from SN1987A, we find that the…
The hypothetical massive dark photon ($\gamma'$) which has kinetic mixing with the SM photon can decay electromagnetically to $e^+e^-$ pairs if its mass $m$ exceeds $2m_e$ and otherwise into three SM photons. These decays yield cosmological…
An impact of a nonzero neutrino millicharge in astrophysics is tested. It is shown that in astrophysical environments electromagnetic interactions of the neutrino millicharge with strong electromagnetic fields as well as weak interactions…
Requiring that the baryon number of the universe be generated by anomalous electroweak interactions places strong constraints on the minimal supersymmetric standard model. In particular, the electric dipole moment of the neutron must be…
Electron-positron pair creation in supercritical electric fields limits the net charge of any static, spherical object, such as superheavy nuclei, strangelets, and Q-balls, or compact stars like neutron stars, quark stars, and black holes.…
If massless leptonic photons associated to electron, muon or tau leptonic number exist they would have been emitted from supernova 1987a via the annihilation process $\nu\bar{\nu}\to\gamma_{l}\gamma_{l}$. By requiring that this process does…
We derive the allowed mass range for the superlight gravitino present in a large class of supersymmetric models from the observed luminosity from Supernova 1987A. We find that for photino masses of order 100 GeV, the mass range $2.6\times…
Using modern high-resolution observations of extragalactic compact radio sources we obtain an estimate of the upper bound on a photon electric charge at the level $e_{\gamma} \lesssim 3 \cdot 10^{-33}$ of elementary charge (assuming the…
This paper establishes new bounds on the maximum number of electrons $ N_c(Z) $ that an atom with nuclear charge $Z$ can bind. Specifically, we show that \begin{equation*} N_c(Z) < 1.1185Z + O(Z^{1/3}) \end{equation*} with an explicit bound…
The best upper bounds on the masses of stable and unstable light neutrinos derive from the upper bound on the total mass density, as inferred from the lower limit $t_0> 13$ Gyr on the dynamical age of the Universe: If the Universe is…
We analyze the effect of a variation of the strange nucleon matrix element $\langle N| m_s \bar{s}s|N\rangle$ on the abundances of the light elements produced in the Big Bang. For that, we vary the nucleon mass in the leading eight…
The extreme properties of neutron stars provide unique opportunities to put constraints on new particles and interactions. In this paper, we point out a few interesting ideas that place constraints on light millicharged fermions, with…
The effects of a nonzero photon rest mass can be incorporated into electromagnetism in a simple way using the Proca equations. In this vein, two interesting implications regarding the possible existence of a massive photon in nature, i.e.,…