DAMA observes an annual modulation in their event rate, as might be expected from dark matter scatterings, while CoGeNT has reported evidence for a similar modulation. The simplest interpretation of these findings in terms of dark matter-nucleus scatterings is excluded by other direct detection experiments. We consider the robustness of these exclusions with respect to assumptions regarding the scattering and find that isospin-violating inelastic dark matter helps alleviate this tension and allows marginal compatibility between experiments. Isospin violation can significantly weaken the XENON constraints, while inelasticity enhances the annual modulation fraction of the signal, bringing the CoGeNT and CDMS results into better agreement.

An electroweak singlet scalar can couple to pairs of vector bosons through loop-induced dimension five operators. Compared to a standard model Higgs boson, the singlet decay widths in the diphotons and $Z\gamma$ channels are generically enhanced, while decays into massive final states like $WW$ and $ZZ$ are kinematically disfavored. The overall event rates into $\gamma \gamma$ and $Z\gamma$ can exceed the standard model expectations by orders of magnitude. Such a singlet may appear as a resonant signal in the $\gamma \gamma$ and $Z\gamma$ channels, even with a mass above the $WW$ kinematic threshold.

In this paper we consider the effects of top-quark compositeness on the electroweak parameters $\widehat{T}$ and $\widehat{S}$ and the $Z{b}_L{\overline{b}}_L$ coupling. We do so by using an effective field theory analysis to identify several promising patterns of mixing between standard-model-like and vector fermions, and then analyzing simple extensions of the standard model that realize those patterns. These models illustrate four ways in which an extended $O(4)$ symmetry, which controls the size of radiative corrections to the observables discussed, may be broken. These models may also be viewed as highly deconstructed versions of five-dimensional gauge theories dual to various strongly interacting composite Higgs theories. We comment on how our results relate to extra-dimensional models previously considered, and we demonstrate that one pattern of $O(4)$ breaking is phenomenologically favored.

We analyze the reach of linear colliders for models of dynamical electroweak symmetry breaking. We show that linear colliders can efficiently test the compositeness scale, identified with the mass of the new spin-one resonances, until the maximum energy in the center of mass of the colliding leptons. In particular we analyze the Drell-Yan processes involving spin-one intermediate heavy bosons decaying either leptonically or into two standard model gauge bosons. We also analyze the light Higgs production in association with a standard model gauge boson stemming also from an intermediate spin-one heavy vector.

We investigate the LHC discovery potential of $R$-parity violating supersymmetric models with a right-handed selectron or smuon as the lightest supersymmetric particle. These particles arise naturally in $R$-parity violating minimal supergravity models. We classify the hadron collider signatures and perform for the first time within these models a detailed signal over background analysis. We develop an inclusive three-lepton search and give prospects for a discovery at a center-of-mass energy of $\sqrt{s}=7\mathrm{TeV}$ as well as $\sqrt{s}=14\mathrm{TeV}$. There are extensive parameter regions which the LHC can already test with $\sqrt{s}=7\mathrm{TeV}$ and an integrated luminosity of $1{\mathrm{fb}}^{-1}$. We also propose a method for the mass reconstruction of the supersymmetric particles within our models at $\sqrt{s}=14\mathrm{TeV}$.

We investigate low-lying fermion modes in $SU(2)$ gauge theory at temperatures above the phase transition. Both staggered and overlap spectra reveal transitions from chaotic (random matrix) to integrable (Poissonian) behavior accompanied by an increasing localization of the eigenmodes. We show that the latter are trapped by local Polyakov loop fluctuations. Islands of such “wrong” Polyakov loops can therefore be viewed as defects leading to Anderson localization in gauge theories. We find strong similarities in the spatial profile of these localized staggered and overlap eigenmodes. We discuss possible interpretations of this finding and present a sparse random matrix model that reproduces these features.

Transverse-momentum dependent parton distributions (TMDs) are studied in the framework of quark models. In particular, quark-model relations among TMDs are reviewed, elucidating their physical origin in terms of the quark-spin structure in the nucleon. The formal aspects of the derivation of these relations are complemented with explicit examples, emphasizing how and to which extent the conditions which lead to relations among TMDs are implemented in different classes of quark models.

We present a decomposition of the hadronic tensor for a general polarized Drell-Yan process $AB\to {\ell }^{+}{\ell }^{-}X$ in terms of helicity structure functions using the helicity axes of the dilepton rest frame as a basis. Next, we consider a QCD parton model in the framework of a generalized QCD factorization scheme, which applies when the dilepton invariant mass $M$ is much larger than the transverse component of the photon momentum, $q_T$, in the hadronic center of mass frame. In this approximation we compute the angular distribution of the unpolarized Drell-Yan cross section and of the Sivers effect, in single polarized Drell-Yan scattering, by taking into account the transverse motion of partons inside the initial hadrons, $k_{\perp }$. Interesting and simple results are found in the kinematical region $k_{\perp }\simeq q_T\ll M$, to first order in a $q_T/M$ expansion. Finally, explicit analytical expressions, convenient for phenomenological studies, are obtained assuming a factorized Gaussian dependence on intrinsic momenta for the unpolarized and Sivers distribution functions, in analogy to those obtained for semi-inclusive deep inelastic scattering.

We study the indirect detection of dark matter through neutrino flux from their annihilation in the center of the Sun, in a class of theories where the dark matter-nucleon spin-independent interactions break the isospin symmetry. We point out that, while the direct-detection bounds with heavy targets like xenon are weakened and reconciled with the positive signals in DAMA and CoGeNT experiments, the indirect detection using neutrino telescopes can impose a relatively stronger constraint and brings tension to such an explanation, if the annihilation is dominated by heavy quark or $\tau$-lepton final states. As a consequence, the qualified isospin-violating dark matter candidate has to preferably annihilate into light flavors.

The hemisphere soft function is calculated to order ${\alpha }_s^2$. This is the first multiscale soft function calculated to two loops. The renormalization scale dependence of the result agrees exactly with the prediction from effective field theory. This fixes the unknown coefficients of the singular parts of the two-loop thrust and heavy-jet mass distributions. There are four such coefficients, for 2 event shapes and 2 color structures, which are shown to be in excellent agreement with previous numerical extraction. The asymptotic behavior of the soft function has double logs in the $C_F{C}_A$ color structure, which agree with nonglobal log calculations, but also has subleading single logs for both the $C_F{C}_A$ and $C_F{T}_F{n}_f$ color structures. The general form of the soft function is complicated, does not factorize in a simple way, and disagrees with the Hoang-Kluth ansatz. The exact hemisphere soft function will remove one source of uncertainty on the ${\alpha }_s$ fits from $e^{+}{e}^{-}$ event shapes.

We study properties of moduli stabilization in the four dimensional $\mathcal{N}=1$ supergravity theory with heavy moduli and would-be saxion-axion multiplets, including light string-theoretic axions. We give general formulation for the scenario that heavy moduli and saxions are stabilized while axions remain light, assuming that moduli are stabilized near the supersymmetric solution. One can find stable vacuum, i.e. nontachyonic saxions, in the nonsupersymmetric Minkowski vacua. We also discuss the cases where the moduli are coupled to the supersymmetry breaking sector and/or moduli have contributions to supersymmetry breaking. Futhermore, we study the models with axions originating from matterlike fields. Our analysis on moduli stabilization is applicable even if there are not light axion multiplets.

A standard approach to investigate the nonperturbative QCD dynamics is through vacuum models which emphasize the role played by specific gauge field fluctuations, such as instantons, monopoles, or vortexes. The effective Hamiltonian describing the dynamics of the low-energy degrees of freedom in such approaches is usually postulated phenomenologically, or obtained through uncontrolled approximations. In a recent paper, we have shown how lattice field theory simulations can be used to rigorously compute the effective Hamiltonian of arbitrary vacuum models by stochastically performing the path integral over all the vacuum field fluctuations which are not explicitly taken into account. In this work, we present the first illustrative application of such an approach to a gauge theory and we use it to compute the instanton size distribution in $SU(2)$ gluon dynamics in a fully model independent and parameter-free way.

We propose that $N$ M5-branes, put on ${\mathbb{R}}^4/{\mathbb{Z}}_m$ with deformation parameters ${ϵ}_{1,2}$, realize two-dimensional theory with $\widehat{\mathrm{SU}}(m{)}_N$ symmetry and $m$th para-$W_N$ symmetry. This includes the standard $W_N$ symmetry for $m=1$ and super-Viraroro symmetry for $m=N=2$. We provide a small check of this proposal by calculating the central charge of the 2D theory from the anomaly polynomial of the 6D theory.

We study the matrix models that result from the localization of the partition functions of $\mathcal{N}=2$ Chern-Simons–matter theories on the three-sphere. A large class of such theories are conjectured to be holographically dual to M-theory on Sasaki-Einstein seven-manifolds. We study the M-theory limit (large $N$ and fixed Chern-Simons levels) of these matrix models for various examples, and show that in this limit the free energy reproduces the expected AdS/CFT result of $N^{3/2}/\mathrm{Vol}(Y{)}^{1/2}$, where $\mathrm{Vol}(Y)$ is the volume of the corresponding Sasaki-Einstein metric. More generally we conjecture a relation between the large $N$ limit of the partition function, interpreted as a function of trial $R$ charges, and the volumes of Sasakian metrics on links of Calabi-Yau fourfold singularities. We verify this conjecture for a family of $U(N{)}^2$ Chern-Simons quivers based on M2 branes at hypersurface singularities, and for a $U(N{)}^3$ theory based on M2 branes at a toric singularity.

We study the strong coupling problem in the Horava-Melby-Thompson setup of the Horava-Lifshitz theory of gravity with an arbitrary coupling constant $\lambda$, generalized recently by da Silva, where $\lambda$ describes the deviation of the theory in the infrared from general relativity that has ${\lambda }_{\mathrm{GR}}=1$. We find that a scalar field in the Minkowski background becomes strongly coupled for processes with energy higher than ${\Lambda }_{\omega }[\equiv (M_{pl}/c_1{)}^{3/2}{M}_{pl}|\lambda -1{|}^{5/4}]$, where generically $c_1\ll M_{pl}$. However, this problem can be cured by introducing a new energy scale $M_{*}$, so that $M_{*}<{\Lambda }_{\omega }$, where $M_{*}$ denotes the suppression energy of high-order derivative terms of the theory.

The CoGeNT Collaboration has reported evidence of an annual modulation in its first 15 months of data. Here we compare the amplitude and phase of this signal to the modulation observed by the DAMA Collaboration, assuming that both arise due to elastically scattering dark matter (DM). We directly map the CoGeNT signal to the DAMA detector without specifying any astrophysical parameters and compare this with the signal measured by DAMA. We also compare with constraints from CDMS II and XENON10. We find that DM of mass 5–14 GeV that couples equally to protons and neutrons is strongly disfavored. Isospin-violating DM fares better but requires a boosted modulation fraction.

A fundamental assumption in cosmology is that of statistical isotropy—that the Universe, on average, looks the same in every direction in the sky. Statistical isotropy has recently been tested stringently using cosmic microwave background data, leading to intriguing results on large angular scales. Here we apply some of the same techniques used in the cosmic microwave background to the distribution of galaxies on the sky. Using the multipole vector approach, where each multipole in the harmonic decomposition of galaxy density field is described by unit vectors and an amplitude, we lay out the basic formalism of how to reconstruct the multipole vectors and their statistics out of galaxy survey catalogs. We apply the algorithm to synthetic galaxy maps, and study the sensitivity of the multipole vector reconstruction accuracy to the density, depth, sky coverage, and pixelization of galaxy catalog maps.

We reconsider quantum gravitational threshold corrections to the unification of fermion masses in grand unified theories. We show that the running of the Planck mass can have a sizable effect on these thresholds that are thus much more important than naively expected. These corrections make any extrapolation from low energy measurements challenging.

The features of the hot and dense gas of quarks, which are considered as the quasiparticles of the model Hamiltonian with a four-fermion interaction, are studied. Being adapted to the Nambu–Jona-Lasinio model, this approach allows us to accommodate a phase transition similar to the nuclear liquid-gas one at the proper scale and to argue the existence of the mixed (inhomogeneous) phase of vacuum and normal baryonic matter as a plausible scenario of chiral symmetry (partial) restoration. Analyzing the transition layer between two phases, we estimate the surface tension coefficient and speculate on the possible existence of a quark droplet.