Signatures of Earth-scattering in the direct detection of Dark Matter

Direct detection experiments search for the interactions of Dark Matter (DM) particles with nuclei in terrestrial detectors. But if these interactions are sufficiently strong, DM particles may scatter in the Earth, affecting their distribution in the lab. We present a new analytic calculation of this `Earth-scattering' effect in the regime where DM particles scatter at most once before reaching the detector. We perform the calculation self-consistently, taking into account not only those particles which are scattered away from the detector, but also those particles which are deflected towards the detector. Taking into account a realistic model of the Earth and allowing for a range of DM-nucleon interactions, we present the EarthShadow code, which we make publicly available, for calculating the DM velocity distribution after Earth-scattering. Focusing on low-mass DM, we find that Earth-scattering reduces the direct detection rate at certain detector locations while increasing the rate in others. The Earth's rotation induces a daily modulation in the rate, which we find to be highly sensitive to the detector latitude and to the form of the DM-nucleon interaction. These distinctive signatures would allow us to unambiguously detect DM and perhaps even identify its interactions in regions of the parameter space within the reach of current and future experiments.Comment: 27 pages + appendices, 9 figures. Code (and animations) available at https://github.com/bradkav/EarthShadow (Astrophysics Source Code Library, record ascl:1611.012). v2: added references, matches version published in JCA

Towards Working Technicolor: Effective Theories and Dark Matter

A fifth force, of technicolor type, responsible for breaking the electroweak theory is an intriguing extension of the Standard Model. Recently new theories have been shown to feature walking dynamics for a very low number of techniflavors and are not ruled out by electroweak precision measurements. We identify the light degrees of freedom and construct the associated low energy effective theories. These can be used to study signatures and relevant processes in current and future experiments. In our theory the technibaryons are pseudo Goldstone bosons and their masses arise via extended technicolor interactions. There are hypercharge assignments for the techniquarks which renders one of the technibaryons electrically neutral. We investigate the cosmological implications of this scenario and provide a component of dark matter.Comment: RevTeX, 17 pages, 2 figures. V2: more precise explanation of formula (33

Limits on Self-Interacting Dark Matter

We impose new severe constraints on the self-interactions of fermionic asymmetric dark matter based on observations of nearby old neutron stars. WIMP self-interactions mediated by Yukawa- type interactions can lower significantly the number of WIMPs necessary for gravitational collapse of the WIMP population accumulated in a neutron star. Even nearby neutron stars located at regions of low dark matter density can accrete sufficient number of WIMPs that can potentially collapse, form a mini black hole, and destroy the host star. Based on this, we derive constraints on the WIMP self-interactions which in some cases are by several orders of magnitude stricter than the ones from the bullet cluster (which are currently considered the most stringent).Comment: 5 page

Metastable and chimera-like states in the C.elegans brain network

We model the neuronal activity of the C.elegans network by coupling Hindmarsh-Rose oscillators through the adjacency matrix obtained from its corresponding brain connectivity. By means of numerical simulations, we produce the parameter spaces for quantities related to synchronization, metastability and chimera-like dynamics, identifying, thus, interesting complex patterns of collective behaviour

Generalised bottom-up holography and walking technicolour

In extradimensional holographic approaches the flavour symmetry is gauged in the bulk, that is, treated as a local symmetry. Imposing such a local symmetry admits fewer terms coupling the (axial) vectors and (pseudo)scalars than if a global symmetry is imposed. The latter is the case in standard low-energy effective Lagrangians. Here we incorporate these additional, a priori only globally invariant terms into a holographic treatment by means of a Stueckelberg completion and alternatively by means of a Legendre transformation. This work was motivated by our investigations concerning dynamical electroweak symmetry breaking by walking technicolour and we apply our findings to these theories.Comment: 12 pages, 5 figure

Photons in gapless color-flavor-locked quark matter

We calculate the Debye and Meissner masses of a gauge boson in a material consisting of two species of massless fermions that form a condensate of Cooper pairs. We perform the calculation as a function of temperature, for the cases of neutral Cooper pairs and charged Cooper pairs, and for a range of parameters including gapped quaisparticles, and ungapped quasiparticles with both quadratic and linear dispersion relations at low energy. Our results are relevant to the behavior of photons and gluons in the gapless color-flavor-locked phase of quark matter. We find that the photon's Meissner mass vanishes, and the Debye mass shows a non-monotonic temperature dependence, and at temperatures of order the pairing gap it drops to a minimum value of order sqrt(alpha) times the quark chemical potential. We confirm previous claims that at zero temperature an imaginary Meissner mass can arise from a charged gapless condensate, and we find that at finite temperature this can also occur for a gapped condensate.Comment: 22 pages, LaTeX; expanded discussion of temperature dependenc

Recent results from the STAR spin program at RHIC

The STAR experiment uses polarized p+p collisions at RHIC to determine the contributions to the spin of the proton from gluon spin and from orbital angular momentum of the quarks and gluons. Selective STAR measurements of the longitudinal double spin asymmetry for inclusive jet and inclusive hadron production are presented here. In addition, we report measurements of the transverse spin asymmetry for di-jet production at mid-rapidity and the transverse single-spin asymmetry for forward pi0 productionComment: 4 pages, 5 figures, presented at GHP06 conferenc

Linear confinement without dilaton in bottom-up holography for walking technicolour

In PRD78(2008)055005 [arXiv:0805.1503 [hep-ph]] and PRD79(2009)075004 [arXiv:0809.1324 [hep-ph]], we constructed a holographic description of walking technicolour theories using both a hard- and a soft-wall model. Here, we show that the dilaton field becomes phenomenologically irrelevant for the spectrum of spin-one resonances once a term is included in the Lagrangian that mixes the Goldstone bosons and the longitudinal components of the axial vector mesons. We show how this mixing affects our previous results and we make predictions about how this description of technicolour can be tested.Comment: 7 pages, no figure

Chimera states in a network-organized public goods game with destructive agents

We found that a network-organized metapopulation of cooperators, defectors, and destructive agents playing the public goods game with mutations can collectively reach global synchronization or chimera states. Global synchronization is accompanied by a collective periodic burst of cooperation, whereas chimera states reflect the tendency of the networked metapopulation to be fragmented in clusters of synchronous and incoherent bursts of cooperation. Numerical simulations have shown that the system's dynamics switches between these two steady states through a first order transition. Depending on the parameters determining the dynamical and topological properties, chimera states with different numbers of coherent and incoherent clusters are observed. Our results present the first systematic study of chimera states and their characterization in the context of evolutionary game theory. This provides a valuable insight into the details of their occurrence, extending the relevance of such states to natural and social systems. Published by AIP Publishing

Zero Sound in Neutron Stars with Dense Quark Matter under Strong Magnetic Fields

We study a neutron star with a quark matter core under extremely strong magnetic fields. We investigate the possibility of an Urca process as a mechanism for the cooling of such a star. We found that apart from very particular cases, the Urca process cannot occur. We also study the stability of zero sound modes under the same conditions. We derive limits for the coupling constant of an effective theory, in order the zero sound to be undamped. We show that zero sound modes can help kinematically to facilitate a cooling process