Can dark matter induce cosmological evolution of the fundamental constants of Nature?

We demonstrate that massive fields, such as dark matter, can directly produce a cosmological evolution of the fundamental constants of Nature. We show that a scalar or pseudoscalar (axion-like) dark matter field $\phi$, which forms a coherently oscillating classical field and interacts with Standard Model particles via quadratic couplings in $\phi$, produces `slow' cosmological evolution and oscillating variations of the fundamental constants. We derive limits on the quadratic interactions of $\phi$ with the photon, electron and light quarks from measurements of the primordial $^4$He abundance produced during Big Bang nucleosynthesis and recent atomic dysprosium spectroscopy measurements. These limits improve on existing constraints by up to 15 orders of magnitude. We also derive limits on the previously unconstrained linear and quadratic interactions of $\phi$ with the massive vector bosons from measurements of the primordial $^4$He abundance.Comment: 7 pages. 1 figure. Version to appear in Physical Review Letters. This final version now includes also results amalgamated from our work arXiv:1504.0179

Reply to comment on "Searching for Topological Defect Dark Matter via Nongravitational Signatures"

In the comment of Avelino, Sousa and Lobo [arXiv:1506.06028], it is argued, by comparing the kinetic energy of a topological defect with the overall energy of a pulsar, that the origin of the pulsar glitch phenomenon due to the passage of networks of topological defects through pulsars is faced with serious difficulties. Here, we point out that topological defects may trigger pulsar glitches within traditional scenarios, such as vortex unpinning. If the energy transfer from a topological defect exceeds the activation energy for a single pinned vortex, this may lead to an avalanche of unpinning of vortices and consequently a pulsar glitch, and therefore the source of angular momentum and energy required for a glitch event is provided by the pulsar itself. Indeed, the activation energy for such a process can be very small (essentially zero compared with the observed increase in the pulsar's rotational kinetic energy at the onset of a glitch). The unpinning of a vortex by a topological defect may occur through the passage of the defect into the core of the pulsar.Comment: 2 page

Nuclear spin-dependent interactions: Searches for WIMP, Axion and Topological Defect Dark Matter, and Tests of Fundamental Symmetries

We calculate the proton and neutron spin contributions for nuclei using semi-empirical methods, as well as a novel hybrid \emph{ab initio}/semi-empirical method, for interpretation of experimental data. We demonstrate that core-polarisation corrections to \emph{ab initio} nuclear shell model calculations generally reduce discrepancies in proton and neutron spin expectation values from different calculations. We derive constraints on the spin-dependent P,T-violating interaction of a bound proton with nucleons, which for certain ranges of exchanged pseudoscalar boson masses improve on the most stringent laboratory limits by several orders of magnitude. We derive a limit on the CPT and Lorentz-invariance-violating parameter $|\tilde{b}_{\perp}^p| < 7.6 \times 10^{-33}$ GeV, which improves on the most stringent existing limit by a factor of 8, and demonstrate sensitivities to the parameters $\tilde{d}_{\perp}^p$ and $\tilde{g}_{ D\perp}^p$ at the level $\sim 10^{-29} - 10^{-28}$ GeV, which is a one order of magnitude improvement compared to the corresponding existing sensitivities. We extend previous analysis of nuclear anapole moment data for Cs to obtain new limits on several other CPT and Lorentz-invariance-violating parameters: $\left|b_0^p \right| < 7 \times 10^{-8}$ GeV, $\left|d_{00}^p \right| < 8 \times 10^{-8}$, $\left|b_0^n \right| < 3 \times 10^{-7}$ GeV and $\left|d_{00}^n \right| < 3 \times 10^{-7}$.Comment: 8 pages. The present work is a significantly extended and improved version of our previous work, and contains many new result

Probing low-mass vector bosons with parity nonconservation and nuclear anapole moment measurements in atoms and molecules

In the presence of P-violating interactions, the exchange of vector bosons between electrons and nucleons induces parity-nonconserving (PNC) effects in atoms and molecules, while the exchange of vector bosons between nucleons induces anapole moments of nuclei. We perform calculations of such vector-mediated PNC effects in Cs, Ba$^+$, Yb, Tl, Fr and Ra$^+$ using the same relativistic many-body approaches as in earlier calculations of standard-model PNC effects, but with the long-range operator of the weak interaction. We calculate nuclear anapole moments due to vector boson exchange using a simple nuclear model. From measured and predicted (within the standard model) values for the PNC amplitudes in Cs, Yb and Tl, as well as the nuclear anapole moment of $^{133}$Cs, we constrain the P-violating vector-pseudovector nucleon-electron and nucleon-proton interactions mediated by a generic vector boson of arbitrary mass. Our limits improve on existing bounds from other experiments by many orders of magnitude over a very large range of vector-boson masses.Comment: 5 pages, 2 figure