The Effective Field Theory of Dark Matter Direct Detection

We extend and explore the general non-relativistic effective theory of dark matter (DM) direct detection. We describe the basic non-relativistic building blocks of operators and discuss their symmetry properties, writing down all Galilean-invariant operators up to quadratic order in momentum transfer arising from exchange of particles of spin 1 or less. Any DM particle theory can be translated into the coefficients of an effective operator and any effective operator can be simply related to most general description of the nuclear response. We find several operators which lead to novel nuclear responses. These responses differ significantly from the standard minimal WIMP cases in their relative coupling strengths to various elements, changing how the results from different experiments should be compared against each other. Response functions are evaluated for common DM targets - F, Na, Ge, I, and Xe - using standard shell model techniques. We point out that each of the nuclear responses is familiar from past studies of semi-leptonic electroweak interactions, and thus potentially testable in weak interaction studies. We provide tables of the full set of required matrix elements at finite momentum transfer for a range of common elements, making a careful and fully model-independent analysis possible. Finally, we discuss embedding non-relativistic effective theory operators into UV models of dark matter.Comment: 32+23 pages, 5 figures; v2: some typos corrected and definitions clarified; v3: some factors of 4pi correcte

Exact spinor-scalar bound states in a QFT with scalar interactions

We study two-particle systems in a model quantum field theory, in which scalar particles and spinor particles interact via a mediating scalar field. The Lagrangian of the model is reformulated by using covariant Green's functions to solve for the mediating field in terms of the particle fields. This results in a Hamiltonian in which the mediating-field propagator appears directly in the interaction term. It is shown that exact two-particle eigenstates of the Hamiltonian can be determined. The resulting relativistic fermion-boson equation is shown to have Dirac and Klein-Gordon one-particle limits. Analytic solutions for the bound state energy spectrum are obtained for the case of massless mediating fields.Comment: 12 pages, RevTeX, 1 figur

Exact Path-Integral Representations for the TT-Matrix in Nonrelativistic Potential Scattering

Several path integral representations for the $T$-matrix in nonrelativistic potential scattering are given which produce the complete Born series when expanded to all orders and the eikonal approximation if the quantum fluctuations are suppressed. They are obtained with the help of "phantom" degrees of freedom which take away explicit phases that diverge for asymptotic times. Energy conservation is enforced by imposing a Faddeev-Popov-like constraint in the velocity path integral. An attempt is made to evaluate stochastically the real-time path integral for potential scattering and generalizations to relativistic scattering are discussed.Comment: 6 pages, 2 figures. Contribution to the workshop "Relativistic Description of Two- and Three-Body Systems in Nuclear Physics", ETC*, October 19-23, 2009. v2: typo corrected, matches published version + additional reference

Assessing the impact of the physical properties of industrially produced carbon nanotubes on their interaction with human primary macrophages in vitro

Currently it is not fully understood how carbon nanotubes (CNTs) may affect human health. Despite this, CNTs are produced at a tonne mass scale yearly. Due to their large production and intended use within a variety of applications it is imperative that a clear understanding of the hazard potential of CNTs is gained. The aim of this study therefore was to assess the impact of five different industrially produced CNTs which varied in their physical properties on the viability of human monocyte derived macrophages (MDM), and subsequently, at sub-lethal concentrations (0.005-0.02 mg/mL), their ability to cause oxidative stress and a pro-inflammatory response in these important immune cells over a 24-h period. None of the CNTs caused significant cytotoxicity up to 0.02 mg/mL after 24 h. Only the long multi-walled CNTs (MWNCTs) caused a significant, dose-dependent (0.005-0.02 mg/mL) reactive oxygen species production, whilst bundled MWCNTs showed a significant tumor necrosis factor alpha release after 24 h exposure at 0.02 mg/mL. No effects were observed for either tangled MWCNTs or short MWCNTs. It can be concluded from the findings of the present study that the industrially produced CNTs studied can cause hazardous effects in vitro that may be associated with their physical propertie

Angular Conditions,Relations between Breit and Light-Front Frames, and Subleading Power Corrections

We analyze the current matrix elements in the general collinear (Breit) frames and find the relation between the ordinary (or canonical) helicity amplitudes and the light-front helicity amplitudes. Using the conservation of angular momentum, we derive a general angular condition which should be satisfied by the light-front helicity amplitudes for any spin system. In addition, we obtain the light-front parity and time-reversal relations for the light-front helicity amplitudes. Applying these relations to the spin-1 form factor analysis, we note that the general angular condition relating the five helicity amplitudes is reduced to the usual angular condition relating the four helicity amplitudes due to the light-front time-reversal condition. We make some comments on the consequences of the angular condition for the analysis of the high-$Q^2$ deuteron electromagnetic form factors, and we further apply the general angular condition to the electromagnetic transition between spin-1/2 and spin-3/2 systems and find a relation useful for the analysis of the N-$\Delta$ transition form factors. We also discuss the scaling law and the subleading power corrections in the Breit and light-front frames.Comment: 24 pages,2 figure

Solar Wakes of Dark Matter Flows

We analyze the effect of the Sun's gravitational field on a flow of cold dark matter (CDM) through the solar system in the limit where the velocity dispersion of the flow vanishes. The exact density and velocity distributions are derived in the case where the Sun is a point mass. The results are extended to the more realistic case where the Sun has a finite size spherically symmetric mass distribution. We find that regions of infinite density, called caustics, appear. One such region is a line caustic on the axis of symmetry, downstream from the Sun, where the flow trajectories cross. Another is a cone-shaped caustic surface near the trajectories of maximum scattering angle. The trajectories forming the conical caustic pass through the Sun's interior and probe the solar mass distribution, raising the possibility that the solar mass distribution may some day be measured by a dark matter detector on Earth. We generalize our results to the case of flows with continuous velocity distributions, such as that predicted by the isothermal model of the Milky Way halo.Comment: 30 pages, 8 figure

Solving the Bethe-Salpeter Equation for Scalar Theories in Minkowski Space

The Bethe-Salpeter (BS) equation for scalar-scalar bound states in scalar theories without derivative coupling is formulated and solved in Minkowski space. This is achieved using the perturbation theory integral representation (PTIR), which allows these amplitudes to be expressed as integrals over weight functions and known singularity structures and hence allows us to convert the BS equation into an integral equation involving weight functions. We obtain numerical solutions using this formalism for a number of scattering kernels to illustrate the generality of the approach. It applies even when the na\"{\i}ve Wick rotation is invalid. As a check we verify, for example, that this method applied to the special case of the massive ladder exchange kernel reproduces the same results as are obtained by Wick rotation.Comment: 23 pages with 3 uuencoded, compressed Postscript figures. Entire manuscript available as a ps file at http://www.physics.adelaide.edu.au/theory/home.html . Also available at ftp://adelphi.adelaide.edu.au/pub/theory/ADP-94-24.T164.p

Efeito da Gliricidia sepium sobre nutrientes do solo, microclima e produtividade do milho em sistema agroflorestal no Agreste Paraibano.

Gliricidia sepium é uma leguminosa arbórea que tem sido utilizada em sistemas em aléias no semi-árido nordestino por apresentar bom desenvolvimento em condições de estresse hídrico. Entretanto, há pouca informação disponível sobre o efeito da introdução dessa espécie nos agroecossistemas da região. No presente estudo, objetivou-se avaliar a influência da distância de plantas de Gliricidia sepium sobre características da cultura do milho e do solo e microclima no Agreste Paraibano. O estudo foi realizado no município de Esperança (PB), em área de 0,5 ha, onde, em 1996, foram plantadas fileiras de G. sepium espaçadas 6 m entre si e com 1 m entre as árvores. Nesta área, em 2002, foram delimitadas quatro parcelas de 6 x 8 m e, em cada parcela, foi estabelecido um transeto perpendicular às fileiras de árvores com três posições de amostragem: (1) nas fileiras de árvores (0 m); (2) a 1 m das fileiras de árvores, e (3) a 3 m de distância das fileiras de árvores. O delineamento experimental utilizado foi em blocos casualizados com quatro repetições. A massa seca de folhedo caído embaixo da fileira de árvores foi de 1.390 kg ha-1 e diminuiu, gradativamente, para 270 kg ha-1 a 3 m de distância das árvores. As concentrações de P, K e matéria orgânica leve (MOL) embaixo das árvores foram maiores do que a 1 e 3 m de distância das fileiras. As médias mensais das temperaturas mínimas do ar e do solo embaixo e a 3 m das árvores foram similares. Entretanto, as médias mensais das temperaturas máximas do solo e do ar foram de 6 e 2 °C mais altas a 3 m das árvores, respectivamente, ao longo do período de estudo. A umidade do solo foi significativamente menor embaixo das árvores do que a 1 e 3 m de distância. O milho produziu mais grãos e palha e acumulou mais nutrientes nas posições mais próximas das fileiras de G. sepium

Measurement of (anti)deuteron and (anti)proton production in DIS at HERA

The first observation of (anti)deuterons in deep inelastic scattering at HERA has been made with the ZEUS detector at a centre-of-mass energy of 300--318 GeV using an integrated luminosity of 120 pb-1. The measurement was performed in the central rapidity region for transverse momentum per unit of mass in the range 0.3<p_T/M<0.7. The particle rates have been extracted and interpreted in terms of the coalescence model. The (anti)deuteron production yield is smaller than the (anti)proton yield by approximately three orders of magnitude, consistent with the world measurements.Comment: 26 pages, 9 figures, 5 tables, submitted to Nucl. Phys.

D* Production in Deep Inelastic Scattering at HERA

This paper presents measurements of D^{*\pm} production in deep inelastic scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The data have been taken with the ZEUS detector at HERA. The decay channel $D^{*+}\to (D^0 \to K^- \pi^+) \pi^+$ (+ c.c.) has been used in the study. The $e^+p$ cross section for inclusive D^{*\pm} production with $5<Q^2<100 GeV^2$ and $y<0.7$ is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region {$1.3<p_T(D^{*\pm})<9.0$ GeV and $| \eta(D^{*\pm}) |<1.5$}. Differential cross sections as functions of p_T(D^{*\pm}), $\eta(D^{*\pm}), W$ and $Q^2$ are compared with next-to-leading order QCD calculations based on the photon-gluon fusion production mechanism. After an extrapolation of the cross section to the full kinematic region in p_T(D^{*\pm}) and $\eta$(D^{*\pm}), the charm contribution $F_2^{c\bar{c}}(x,Q^2)$ to the proton structure function is determined for Bjorken $x$ between 2 $\cdot$ 10$^{-4}$ and 5 $\cdot$ 10$^{-3}$.Comment: 17 pages including 4 figure