We study the complete cosmological evolution of dark matter (DM) density fluctuations for DM particles that decoupled being ultrarelativistic during the radiation dominated era which is the case of keV scale warm DM (WDM). The new framework presented here can be applied to other types of DM and, in particular, we extend it to cold DM. The collisionless and linearized Boltzmann-Vlasov equations (B-V) for WDM and neutrinos in the presence of photons and coupled to the linearized Einstein equations are studied in detail in the presence of anisotropic stress with the Newtonian potential generically different from the spatial curvature perturbations. We recast this full system of B-V equations for DM and neutrinos into a system of coupled Volterra integral equations. These Volterra-type equations are valid both in the radiation dominated and matter dominated eras during which the WDM particles are ultrarelativistic and then nonrelativistic. This generalizes the so-called Gilbert integral equation only valid for nonrelativistic particles in the matter dominated era. We succeed to reduce the system of four Volterra integral equations for the density and anisotropic stress fluctuations of DM and neutrinos into a system of only two coupled Volterra equations. The kernels and inhomogeneities in these equations are explicitly given functions. Combining the Boltzmann-Vlasov equations and the linearized Einstein equations constrain the initial conditions on the distribution functions and gravitational potentials. In the absence of neutrinos the anisotropic stress vanishes and the Volterra-type equations reduce to a single integral equation. These Volterra integral equations provide a useful and precise framework to compute the primordial WDM fluctuations over a wide range of scales including small scales up to $k\sim 1/5\mathrm{kpc}$.

We explore the capability of the IceCube/DeepCore array to discover signal neutrinos resulting from the annihilations of supersymmetric weakly interacting massive particles that may be captured in the solar core. In this analysis, we use a previously generated set of $\sim 70\mathrm{k}$ model points in the 19-dimensional parameter space of the phenomenological minimal supersymmetric standard model (pMSSM) which satisfy existing experimental and theoretical constraints. Our calculations employ a realistic estimate of the IceCube/DeepCore effective area that has been modeled by the IceCube collaboration. We find that a large fraction of the pMSSM models are shown to have significant signal rates in the anticipated IceCube/DeepCore 1825 d data set, including some prospects for an early discovery. Many models where the lightest supersymmetric particle only constitutes a small fraction of the total dark matter relic density are found to have observable rates. We investigate in detail the dependence of the signal neutrino fluxes on the lightest-supersymmetric-particle mass, weak eigenstate composition, annihilation products and thermal relic density, as well as on the spin-independent and spin-dependent scattering cross sections. Lastly, we compare the model coverage of IceCube/DeepCore to that obtainable in near-future direct-detection experiments and to pMSSM searches at the 7 TeV LHC.

We discuss the impact and potential discovery of physics beyond the standard model, coupling to the Higgs sector, at the LHC. Using a model-independent effective Lagrangian approach, pure Higgs and Higgs-gauge operators are analyzed, and their origin in terms of tree-level exchange of unknown heavy messengers is systematically derived. It is demonstrated that early signals at the LHC may result from a simultaneous modification of Higgs-fermion and Higgs-gauge boson couplings induced by those operators, pointing towards singlet scalar or a triplet vector—barring fine-tuned options. Of course, the Higgs discovery itself will also be affected by such new couplings. With increasing statistics, the remaining options can be discriminated from each other. On the other hand, the discovery of a new scalar doublet may require technology beyond the LHC, since the Higgs self-couplings have to be measured. Our conclusions are based on the complete set of tree-level decompositions of the effective operators unbiased by a specific model.

The ${\pi }^{+}{\pi }^{+}$ $s$-wave scattering phase shift is determined below the inelastic threshold using lattice QCD. Calculations were performed at a pion mass of $m_{\pi }\sim 390\mathrm{MeV}$ with an anisotropic $n_f=2+1$ clover fermion discretization in four lattice volumes, with spatial extent $L\sim 2.0$, 2.5, 3.0 and 3.9 fm, and with a lattice spacing of $b_s\sim 0.123\mathrm{fm}$ in the spatial direction and $b_t\sim b_s/3.5$ in the time direction. The phase shift is determined from the energy eigenvalues of ${\pi }^{+}{\pi }^{+}$ systems with both zero and nonzero total momentum in the lattice volume using Lüscher’s method. Our calculations are precise enough to allow for a determination of the threshold scattering parameters, the scattering length $a$, the effective range $r$, and the shape parameter $P$, in this channel and to examine the prediction of two-flavor chiral perturbation theory: $m_{\pi }^{2}ar=3+\mathcal{O}(m_{\pi }^2/{\Lambda }_{\chi }^2)$. Chiral perturbation theory is used, with the lattice QCD results as input, to predict the scattering phase shift (and threshold parameters) at the physical pion mass. Our results are consistent with determinations from the Roy equations and with the existing experimental phase shift data.

The gluonic action density is calculated in static mesons at finite temperature just below the deconfinement point. Our focus is to elucidate the role of vacuum ultraviolet fluctuations which are filtered using an improved smearing algorithm. In the intermediate source separation distance, where the free string picture poorly describes the flux tube width profile, we find upon reducing the vacuum action towards the classical instanton vacuum, the characteristics of the flux tube converge and compare favorably with the predictions of the free bosonic string. This result establishes a connection between the free string action and vacuum gauge fields and reveals the important role of ultraviolet physics in understanding the lattice data at this temperature scale. As a by-product of these calculations, we find the broadening of the QCD flux tube to be independent of the ultraviolet filtering at large distances. Our results exhibit a linearly divergent pattern in agreement with the string picture predictions.

In time for the first tests on LHC data we introduce a set of improvements and tests of purely kinematic top tagging algorithms. First, we show how different jet algorithms can be used for different transverse momentum regimes. Combining pruning and filtering in the reconstruction can enhance the signal over background ratio significantly, while larger jet radii only give minor improvements. Finally, bottom tagging can be added to the top tagger, but at least for the HEPTopTagger does not improve the kinematic selection algorithm.

In this paper, the twist-3 distribution amplitude of the quark-antiquark-gluon Fock state in the ${\eta }_c$ meson is studied. To calculate the moments of this distribution amplitude, QCD sum rules are applied. Using the results of the calculation, the model of this distribution amplitude is built. In addition, nonrelativistic QCD matrix elements that determine the properties of the quark-antiquark-gluon Fock state are determined. In particular, the following properties have been calculated: probability amplitude to find the quark-antiquark pair in the color-octet state, fraction of momentum carried by gluon, relative velocity of the color-octet quark-antiquark pair.

We analyze the motion of an electric charge in the field of a magnetically charged event in three-dimensional spacetime. We start by exhibiting a first integral of the equations of motion in terms of the three conserved components of the spacetime angular momentum, and then proceed numerically. After crossing the light cone of the event, an electric charge initially at rest starts rotating and slowing down. There are two lengths appearing in the problem: (i) the characteristic length $\frac{qg}{2\pi m}$, where $q$ and $m$ are the electric charge and mass of the particle, and $g$ is the magnetic charge of the event; and (ii) the spacetime impact parameter $r_0$. For $r_0\gg \frac{qg}{2\pi m}$, after a time of order $r_0$, the particle makes sharply a quarter of a turn and comes to rest at the same spatial position at which the event happened in the past. This jump is the main signature of the presence of the magnetic event as felt by an electric charge. A derivation of the expression for the angular momentum that uses Noether’s theorem in the magnetic representation is given in the Appendix.

We consider Schrödinger equations for a nonrelativistic particle obeying an $N+1$-th order higher derivative classical equation of motion. These equations are invariant under $N$ (odd)-extended Galilean conformal algebras in general $d+1$ dimensions. In $2+1$ dimensions, the exotic Schrödinger equations are invariant under $N$ (even)-Galilean conformal algebras.

Spherical clusters of $SU(2)$ Bogomol’nyi-Prasad-Sommerfield monopoles are investigated here. A large class of monopole solutions is found using an Abelian approximation, where the clusters are spherically symmetric, although exact solutions cannot have this symmetry precisely. Monopole clusters generalize the Bolognesi magnetic bag solution of the same charge, but they are always larger. Selected density profiles give structures analogous to planets of uniform density, and galaxies with a density decaying as the inverse square of the distance from the center. The Bolognesi bag itself has features analogous to a black hole, and this analogy between monopole clusters and astrophysical objects with or without black holes in their central region is developed further. It is also shown that certain exact, platonic monopoles of small charge have sizes and other features consistent with what is expected for magnetic bags.

We analyze the expectation value of observables in a scalar theory on the fuzzy two-sphere, represented as a generalized Hermitian matrix model. We calculate explicitly the form of the expectation values in the large-$N$ limit and demonstrate that, for any single kind of field (matrix), the distribution of its eigenvalues is still a Wigner semicircle but with a renormalized radius. For observables involving more than one type of matrix, we obtain a new distribution corresponding to correlated Wigner semicircles.

We extend the recent $D=5$ results of Dias, Horowitz, and Santos by finding asymptotically anti–de Sitter rotating black hole and boson star solutions with scalar hair in arbitrary odd spacetime dimension. Both the black holes and the boson stars are invariant under a single Killing vector field which corotates with the scalar field and, in the black hole case, is tangent to the generator of the horizon. Furthermore, we explicitly construct boson star and small black hole ($r_{+}\ll \ell$) solutions perturbatively assuming a small amplitude for the scalar field, resulting in solutions valid for low energies and angular momenta. We find that just as in $D=5$, the angular momentum is primarily carried by the scalar field in $D>5$, whereas unlike $D=5$ the energy is also primarily carried by the scalar field in $D>5$; the thermodynamics in $D=5$ are governed by both the black hole and scalar field whereas in $D>5$ they are governed primarily by the scalar field alone. We focus on cataloging these solutions for the spacetime dimensions of interest in string theory, namely $D=5,7,9,11$.

We analyze the recently released CoGeNT data with a focus on their time-dependent properties. Using a variety of statistical tests, we confirm the presence of modulation in the data, and find a significant component at high ($E_{ee}\gtrsim 1.5\mathrm{keVee}$) energies. We find that standard elastic WIMPs in a Maxwellian halo do not provide a good description of the modulation. We consider the possibility of nonstandard halos, using halo-independent techniques, and find a good agreement with the DAMA modulation for $Q_{\mathrm{Na}}\approx 0.3$, but disfavoring interpretations with $Q_{\mathrm{Na}}=0.5$. The same techniques indicate that CDMS-Ge should see an $O(1)$ modulation, and XENON100 should have seen 10–30 events (based upon the modulation in the 1.5–3.1 keVee range), unless ${\mathrm{L}}_{\mathrm{eff}}$ is smaller than recent measurements. Models such as inelastic dark matter provide a good fit to the modulation, but not the spectrum. We note that tensions with XENON could be alleviated in such models if the peak is dominantly in April, when XENON data are not available due to noise.

A particular decoupling limit of the nonextremal (D1, D3) brane bound state system of type IIB string theory is known to give the gravity dual of space-space noncommutative Yang-Mills theory at finite temperature. We use a string probe in this background to compute the jet quenching parameter in a strongly coupled plasma of hot noncommutative Yang-Mills theory in ($3+1$) dimensions from gauge/gravity duality. We give expressions for the jet quenching parameter for both small and large noncommutativity. For small noncommutativity, we find that the value of the jet quenching parameter gets reduced from its commutative value. The reduction is enhanced with temperature as $T^7$ for fixed noncommutativity and fixed ’t Hooft coupling. We also give an estimate of the correction due to noncommutativity at the present collider energies like in RHIC or in LHC and find it too small to be detected. We further generalize the results for noncommutative Yang-Mills theories in diverse dimensions.

We study a model whose dynamics is determined by a Maxwell Lagrangian coupled to a complex scalar and a Dirac fermion field, in an ${\mathrm{AdS}}_3$ black hole background. Our study is performed within the context of the Euclidean formalism, in terms of an effective action $S^{\mathrm{eff}}$ that results from integrating out the fermion field. In particular, $S^{\mathrm{eff}}$ includes an induced parity breaking part which reduces, in the weak coupling limit, to Chern-Simons terms for both the gauge and spin connections, with temperature dependent coefficients. We find numerically the effective action minimum and, applying the AdS/CFT correspondence, we discuss the properties of the dual quantum field theory defined on the boundary. We show that, in contrast with what happens in the absence of fermions, the system does not undergo a phase transition at any finite temperature.

A nonperturbative field theoretical approach to flavor physics (Blasone-Vitiello formalism) has been shown to imply a highly nontrivial vacuum state. Although still far from representing a satisfactory framework for a coherent and complete characterization of flavor states, in recent years the formalism has received attention for its possible implications at cosmological scales. In a previous work, we implemented the approach on a simple supersymmetric model (free Wess-Zumino), with flavor mixing, which was regarded as a model for free neutrinos and sneutrinos. The resulting effective vacuum (called flavor vacuum) was found to be characterized by a strong supersymmetry breaking. In this paper we explore the phenomenology of the model and we argue that the flavor vacuum is a consistent source for both dark energy (thanks to the bosonic sector of the model) and dark matter (via the fermionic one). Quite remarkably, besides the parameters connected with neutrino physics, in this model no other parameters have been introduced, possibly leading to a predictive theory of dark energy/matter. Despite its oversimplification, such a toy model already seems capable to shed some light on the observed energy hierarchy between neutrino physics, dark energy and dark matter. Furthermore, we move a step forth in the construction of a more realistic theory, by presenting a novel approach for calculating relevant quantities and hence extending some results to interactive theories, in a completely nonperturbative way.

The method of covariant symbols of Pletnev and Banin is extended to space-times with topology ${\mathbb{R}}^n\times S^1\times \cdots \times S^1$. By means of this tool, we obtain explicit formulas for the diagonal matrix elements and the trace of the heat kernel at finite temperature to fourth order in a strict covariant derivative expansion. The role of the Polyakov loop is emphasized. Chan’s formula for the effective action to one-loop is similarly extended. The expressions obtained apply formally to a larger class of spaces, $h$-spaces, with an arbitrary weight function $h(p)$ in the integration over the momentum of the loop.

We study the capability of a pulsar timing array to individually resolve and localize in the sky monochromatic gravitational wave (GW) sources. Given a cosmological population of inspiralling massive black hole binaries, their observable signal in the pulsar timing array domain is expected to be a superposition of several nearly-monochromatic GWs of different strength. In each frequency bin, the signal is neither a stochastic background nor perfectly resolvable in its individual components. In this context, it is crucial to explore how the information encoded in the spatial distribution of the array of pulsars might help recovering the origin of the GW signal, by resolving individually and locating in the sky the strongest sources. In this paper we develop a maximum-likelihood-based method finalized to this purpose. We test the algorithm against noiseless data showing that up to $P/3$ sources can be resolved and localized in the sky by an array of $P$ pulsars. We validate the code by performing blind searches on both noiseless and noisy data containing an unknown number of signals with different strengths. Even without employing any proper search algorithm, our analysis procedure performs well, recovering and correctly locating in the sky almost all the injected sources.

In this work, we explore the possibility that static and spherically symmetric traversable wormhole geometries are supported by modified teleparallel gravity or $f(T)$ gravity, where $T$ is the torsion scalar. Considering the field equations with an off-diagonal tetrad, a plethora of asymptotically flat exact solutions are found, which satisfy the weak and the null energy conditions at the throat and its vicinity. More specifically, considering $T\equiv 0$, we find the general conditions for a wormhole satisfying the energy conditions at the throat and present specific examples that satisfy the energy conditions throughout the spacetime. As a consistency check, we also verify that in the teleparallel equivalent of general relativity, i.e., $f(T)=T$, one regains the standard general relativistic field equations for wormhole physics. Furthermore, considering specific choices for the $f(T)$ form and for the redshift and shape functions, several solutions of wormhole geometries are found that satisfy the energy conditions at the throat and its neighborhood. As in their general relativistic counterparts, these $f(T)$ wormhole geometries present far-reaching physical and cosmological implications, such as being theoretically useful as shortcuts in spacetime and for inducing closed timelike curves, possibly violating causality.