We obtain a new type of $\mathcal{N}=3$ Yang-Mills Chern-Simons theory from the Mukhi-Papageorgakis Higgs mechanism of the $\mathcal{N}=3$ Gaiotto-Tomasiello theory. This theory has $\mathcal{N}=1$ BPS fuzzy funnel solution, which is expressed in terms of the seven generators of SU(3), excluding $T_8$. We propose that this is an effective theory of multiple D2-branes with D6- and D8-branes background in massive IIA string theory.

We investigate a squashing deformation of 3D $\mathcal{N}=2$ supersymmetric theories on three-sphere, which have four supercharges. The deformation preserves $SU(2{)}_L\times U(1{)}_r$ isometry and all four supersymmetries. We compute the partition function and find nontrivial dependence on the squashing parameter. We also consider the large $N$ limit of a certain class of quiver gauge theories which have free energy of order $N^{3/2}$, and show that the free energy on the squashed sphere differs from that on round sphere by a certain factor depending only on the squashing parameter.

A truncation scheme for the Dyson-Schwinger equations of quantum chromodynamics in Coulomb gauge within the first-order formalism is presented. The truncation is based on an ansatz for the Coulomb kernel occurring in the action. Results at leading loop order and in the infrared are discussed for both the Yang-Mills and quark sectors. It is found that the resulting equations for the static gluon and quark propagators agree with those derived in a quasiparticle approximation to the canonical Hamiltonian approach. Moreover, a connection to the heavy quark limit is established. The equations are analyzed numerically and it is seen that in both the gluonic and quark sectors, a nontrivial dynamical infrared mass scale emerges.

In this work, we consider the possibility that wormhole geometries are sustained by their own quantum fluctuations, in the context of modified dispersion relations. More specifically, the energy density of the graviton one-loop contribution to a classical energy in a wormhole background is considered as a self-consistent source for wormholes. In this semiclassical context, we consider specific choices for the rainbow’s functions and find solutions for wormhole geometries in the cis-Planckian and trans-Planckian regimes. In the former regime, the wormhole spacetimes are not asymptotically flat and need to be matched to an exterior vacuum solution. In the latter trans-Planckian regime, we find that the quantum corrections are exponentially suppressed, which provide asymptotically flat wormhole geometries with a constant shape function, i.e., $b(r)=r_t$, where $r_t$ is the wormhole throat. In addition to this analysis, we also fix the geometry by considering the behavior of a specific shape function through a variational approach which imposes a local analysis to the problem at the wormhole throat. We further explore the respective parameter range of the rainbow’s functions, and find a good agreement with previous work.

The possibility of Lorentz symmetry breaking (LSB) has attracted considerable attention in recent years. Spontaneous LSB, in particular, offers the attractive prospect of the graviton as a Nambu-Goldstone boson. Here we consider the question of spontaneous LSB in lattice gauge theories via formation of fermion condensates in the strong coupling and large $N$ limits. We employ naive massless fermions in a fermionic hopping expansion in the presence of sources coupled to various condensate operators of interest. The expansion is summed in the large $N$ limit in two equivalent ways: (i) direct summation of all leading $N$ graphs and (ii) construction of the corresponding large $N$ effective action for composite operators. When sources are turned off, a variety of fermionic condensates are found to persist. These include the chiral symmetry breaking condensates—thus recovering previous results—but also some LSB condensates, in particular, axial vector and rank-2 tensor condensates. Furthermore, in the presence of internal (global) symmetry groups, formation of condensates “locking” internal and external (Lorentz subgroup) symmetries is found to also become possible. Some implications and open questions are briefly discussed.

Modified gravity theories generically predict a violation of Lorentz invariance, which may lead to a modified dispersion relation for propagating modes of gravitational waves. We construct a parametrized dispersion relation that can reproduce a range of known Lorentz-violating predictions and investigate their impact on the propagation of gravitational waves. A modified dispersion relation forces different wavelengths of the gravitational-wave train to travel at slightly different velocities, leading to a modified phase evolution observed at a gravitational-wave detector. We show how such corrections map to the waveform observable and to the parametrized post-Einsteinian framework, proposed to model a range of deviations from General Relativity. Given a gravitational-wave detection, the lack of evidence for such corrections could then be used to place a constraint on Lorentz violation. The constraints we obtain are tightest for dispersion relations that scale with small power of the graviton’s momentum and deteriorate for a steeper scaling.

It is widely acknowledged that, for formal purposes, a minimally coupled scalar field is equivalent to an effective perfect fluid with equation of state determined by the scalar potential. This correspondence is not complete because the Lagrangian densities ${\mathcal{L}}_1=P$ and ${\mathcal{L}}_2=-\rho$, which are equivalent for a perfect fluid, are not equivalent for a minimally coupled scalar field. The exchange ${\mathcal{L}}_1\leftrightarrow {\mathcal{L}}_2$ amounts to exchanging a canonical scalar field with a phantom scalar field.

We present cosmological models with modified Chaplygin gas (MCG) in the framework of Horava-Lifshitz (HL) theory of gravity. The equation of state (EOS) for a MCG is a three-variable equation determined by $A$, $\alpha$, $B$. The allowed values of these parameters of the EOS are determined using the recent astrophysical and cosmological observational data. For this we consider $H(z)-z$, BAO peak, CMB shift parameter data to obtain a suitable range of values of the parameters for a viable cosmological model. Considering the suitable range of effective neutrino parameter ($\Delta N_{\nu }$), the ranges of values of the B-parameter along with $A_S$ (defined by $A$, $\alpha$, and $B$) and $\alpha$ are determined here by chi-square minimization.

We show that radio bursts from cusps on superconducting strings are linearly polarized, thus providing a signature that can be used to distinguish them from astrophysical sources. We write the event rate of string-generated radio transients in terms of observational variables, namely, the event duration and flux. Assuming a canonical set of observational parameters, we find that the burst event rate can be quite reasonable, e.g., order ten a year for grand unified strings with 100 TeV currents, and a lack of observed radio bursts can potentially place strong constraints on particle physics models.

The deployment of DeepCore array significantly lowers IceCube’s energy threshold to about 10 GeV and enhances the sensitivity of detecting neutrinos from annihilations and decays of light dark matter. To match this experimental development, we calculate the track event rate in DeepCore array due to neutrino flux produced by annihilations and decays of galactic dark matter. We also calculate the background event rate due to the atmospheric neutrino flux for evaluating the sensitivity of DeepCore array to galactic dark matter signatures. Unlike previous approaches, which set the energy threshold for track events at around 50 GeV (this choice avoids the necessity of including the oscillation effect in the estimation of atmospheric background event rate), we have set the energy threshold at 10 GeV to take full advantage of DeepCore array. We compare our calculated sensitivity with those obtained by setting the threshold energy at 50 GeV. We conclude that our proposed threshold energy significantly improves the sensitivity of DeepCore array to the dark matter signature for $m_{\chi }<100\mathrm{GeV}$ in the annihilation scenario and $m_{\chi }<300\mathrm{GeV}$ in the decay scenario.

We show that a generalized Born-Infeld electrodynamics responsible for regular configurations of the static field of a charged particle produces a nonsingular universe that contains a bouncing. This means that the Universe has a previous collapsing phase, attains a minimum value for its scale factor and then enters into an expanding phase. We exhibit such a scenario in the case of an average pure magnetic universe. At its infinity past as well as at its infinite future the distribution of the energy content of the magnetic fluid displays the form of a cosmological constant. Thus such a configuration is an intermediary between asymptotic vacuum states. In other words, this magnetic universe evolves from vacuum to vacuum.

Bipolar spherical harmonics (BiPoSHs) provide a general formalism for quantifying departures in the cosmic microwave background (CMB) from statistical isotropy and from Gaussianity. However, prior work has focused only on BiPoSHs with even parity. Here we show that there is another set of BiPoSHs with odd parity, and we explore their cosmological applications. We describe systematic artifacts in a CMB map that could be sought by measurement of these odd-parity BiPoSH modes. These BiPoSH modes may also be produced cosmologically through lensing by gravitational waves (GWs), among other sources. We derive expressions for the BiPoSH modes induced by the weak lensing of both scalar and tensor perturbations. We then investigate the possibility of detecting parity-breaking physics, such as chiral GWs, by cross-correlating opposite-parity BiPoSH modes with multipole moments of the CMB polarization. We find that the expected signal-to-noise of such a detection is modest.

The axial anomaly contribution to the generalized longitudinal-transverse polarizability ${\delta }_{\mathrm{LT}}$ is calculated within the Regge approach. It is shown that the contribution from the exchange of the $a_1(1260)$ Regge trajectory is nontrivial and might have the key role to explain the large difference between the predictions of chiral perturbation theory and the experimental data for the neutron ${\delta }_{\mathrm{LT}}$. We also present the prediction for the proton ${\delta }_{\mathrm{LT}}$ that will be measured at the Thomas Jefferson National Accelerator Facility in the near future.

We study the production of the lightest neutralinos in the radiative process $e^{+}{e}^{-}\to {\tilde{\chi }}_1^0{\tilde{\chi }}_1^0\gamma$ in low energy supersymmetric models for the International Linear Collider energies with longitudinally polarized electron and positron beams. For this purpose we consider the case of nonminimal supersymmetric standard model as well as the case of minimal supersymmetric standard model. At the first stage of a linear collider, with $\sqrt{s}=500\mathrm{GeV}$, the radiative production of the lightest neutralinos may be a viable channel to study supersymmetric partners of the standard model particles, especially if the other supersymmetric particles are too heavy to be pair produced. We consider in detail the effect of beam polarization on the production cross section. We compare and contrast the dependence of the signal cross section on the parameters of the neutralino sector of the nonminimal and minimal supersymmetric standard model when the electron and positron beams are longitudinally polarized. In order to assess the feasibility of experimentally observing the radiative neutralino production process, we consider the background to this process coming from the standard model process $e^{+}{e}^{-}\to \nu \overline{\nu }\gamma$ with longitudinally polarized electron and positron beams. We also consider the supersymmetric background to the radiative neutralino production process coming from the radiative production of the scalar partners of the neutrinos (sneutrinos) $e^{+}{e}^{-}\to \tilde{\nu }{\tilde{\nu }}^{*}\gamma$, with longitudinally polarized beams. This process can be a background to the radiative neutralino production when the sneutrinos decay invisibly.

We discuss the implications of assuming a four-zero Yukawa texture and a general Higgs potential for the production of neutral Higgs boson pairs at $\gamma \gamma$ colliders through the $\gamma \gamma \to {\varphi }_i{\varphi }_j$ (${\varphi }_i=h$, $H$, $A$) reaction within the context of the two-Higgs-doublet model type III. Exact analytical expressions for the $\gamma \gamma \to {\varphi }_i{\varphi }_j$ reaction are presented. The use of a nonlinear $R_{\xi }$ gauge, which considerably simplifies the loop calculations and renders compact analytical expressions, is stressed. We show that these processes are very sensitive to a general structure of the Higgs potential that impact the triple and quartic couplings of the scalar sector. We present results for scenarios of the parameters of the model that are still consistent with current experimental constraints. It is found that the cross sections for the $\gamma \gamma \to {\varphi }_i{\varphi }_j$ processes can be up to 2 orders of magnitude larger than those gotten in two-Higgs-doublet model type I and type II. The possibility of a light $CP$-odd scalar is also studied.

We study models where the superpartners of the ordinary particles have continuous spectra rather than being discrete states, which can occur when the supersymmetric standard model is coupled to an approximately conformal sector. We show that when superpartners that are well into the continuum are produced at a collider, they tend to have long decay chains that step their way down through the continuum emitting many fairly soft standard model particles along the way, with a roughly spherical energy distribution in the center of mass frame.

The leading-order hadronic contribution to the muon $g-2$, $a_{\mu }^{\mathrm{HAD}}$, is determined entirely from theory using an approach based on Cauchy’s theorem in the complex squared energy $s$-plane. This is possible after fitting the integration kernel in $a_{\mu }^{\mathrm{HAD}}$ with a simpler function of $s$. The integral determining $a_{\mu }^{\mathrm{HAD}}$ in the light-quark region is then split into a low-energy and a high-energy part, the latter given by perturbative QCD (PQCD). The low energy integral involving the fit function to the integration kernel is determined by derivatives of the vector correlator at the origin, plus a contour integral around a circle calculable in PQCD. These derivatives are calculated using hadronic models in the light-quark sector. A similar procedure is used in the heavy-quark sector, except that now everything is calculable in PQCD, thus becoming the first entirely theoretical calculation of this contribution. Using the dual-resonance model realization of large $N_c$ QCD to compute the derivatives of the correlator leads to agreement with the experimental value of $a_{\mu }$. Accuracy, though, is currently limited by the model-dependent calculation of derivatives of the vector correlator at the origin. Future improvements should come from more accurate chiral perturbation theory and/or lattice QCD information on these derivatives, allowing for this method to be used to determine $a_{\mu }^{\mathrm{HAD}}$ accurately entirely from theory, independently of any hadronic model.

The forthcoming LHC measurement of the hadron multiplicity in proton-nucleus collisions is a crucial test of the $k_t$ factorization and gluon saturation based models. Here, we provide quantitative predictions for the pseudorapidity distribution of charged particles produced in minimum-bias proton-nucleus collisions at the LHC based on the idea of gluon saturation in the color glass condensate framework. Our formulation gives good descriptions of the LHC and the Relativistic Heavy Ion Collider (RHIC) data for the charged hadron multiplicities in both proton-proton and nucleus-nucleus collisions, and also the deep inelastic scattering in the Hadron Electron Ring Accelerator (HERA) at small Bjorken-$x$.

An SU(4) extrapolation of the chiral unitary theory in coupled channels done to study the scalar mesons in the charm sector is extended to produce results in finite volume. The theory in the infinite volume produces dynamically the $D_{s^{*}0}(2317)$ resonance by means of the coupled channels $KD$, $\eta D_s$. Energy levels in the finite box are evaluated and, assuming that they would correspond to lattice results, the inverse problem of determining the bound states and phase shifts in the infinite volume from the lattice data is addressed. We observe that it is possible to obtain accurate $KD$ phase shifts and the position of the $D_{s^{*}0}(2317)$ state, but it requires the explicit consideration of the two coupled channels in the analysis if one goes close to the $\eta D_s$ threshold. We also show that the finite volume spectra look rather different in case the $D_{s^{*}0}(2317)$ is a composite state of the two mesons, or if it corresponds to a non molecular state with a small overlap with the two meson system. We then show that a careful analysis of the finite volume data can shed some light on the nature of the $D_{s^{*}0}(2317)$ resonance as a $KD$ molecule or otherwise.