We present the first calculations of self-coupled neutrino flavor oscillations with time integrated luminosities and energy spectra for the neutronization burst of an $\mathrm{O}-\mathrm{Ne}-\mathrm{Mg}$ core-collapse supernova. These calculations allow us to gauge the effects of time varying neutrino luminosity and of the bump in the electron number density profile at the base of the hydrogen envelope in $\mathrm{O}-\mathrm{Ne}-\mathrm{Mg}$ core-collapse supernovae. The bump allows a significant fraction of the low-energy ${\nu }_e$ to survive by rendering their flavor-evolution nonadiabatic. Increasing the luminosity of the neutronization burst shifts the bump-affected ${\nu }_e$ to lower energy with reduced survival probability. Similarly, lowering the luminosity shifts the bump-affected neutrinos to higher energies. While these low-energy neutrinos lie near the edge of detectability, the population of bump-affected neutrinos has direct influence on the spectral swap formation in the neutrino signal at higher energies.

Recently, Navier-Stokes equations have been derived from the duality between the black branes and a conformal fluid on the boundary of ${\mathrm{\text{anti-de Sitter}}}_5$. Nevertheless, the full correspondence has to be established between solutions of supergravity in ${\mathrm{\text{anti-de Sitter}}}_5$ and supersymmetric field theories on the boundary. That prompts the construction of Navier-Stokes equations for a supersymmetric fluid. In the framework of rigid supersymmetry, there are several possibilities and we propose one candidate. We deduce the equations of motion in two ways: both from the divergenceless condition on the energy-momentum tensor and by a suitable parametrization of the auxiliary fields. We give the complete component expansion and a very preliminary analysis of the physics of this supersymmetric fluid.

The purpose of this work is to rewrite the generating functional of ${\varphi }^4$ theory for the $n=0$ and $n=4$ correlation functions as the inner product of a state with an observable, as we did in a previous work, for the two-points correlation function. The observables are defined through the external sources and the states are defined through the correlation function itself. In this sense, the divergences of Quantum Field Theory (QFT) appear in the reduced state by taking the partial trace of the state with respect to the internal vertices that appear in the perturbation expansion. From this viewpoint, the renormalization can be substituted by applying a projector on the internal quantum state. The advantage of this new insight is that we can obtain finite contributions to the correlation functions without introducing counterterms in the Lagrangian or by manipulating complex divergent quantities.

Solutions to scalar theories with derivative self-couplings often have regions where nonlinearities are important. Given a classical source, there is usually a region, demarcated by the Vainshtein radius, inside of which the classical nonlinearities are dominant, while quantum effects are still negligible. If perturbation theory is used to find such solutions, the expansion generally breaks down as the Vainshtein radius is approached from the outside. Here we show that it is possible, by integrating in certain auxiliary fields, to reformulate these theories in such a way that nonlinearities become small inside the Vainshtein radius, and large outside it. This provides a complementary, or classically dual, description of the same theory—one in which nonperturbative regions become accessible perturbatively. We consider a few examples of classical solutions with various symmetries, and find that in all the cases the dual formulation makes it rather simple to study regimes in which the original perturbation theory fails to work. As an illustration, we reproduce by perturbative calculations some of the already known nonperturbative results, for a pointlike source, cosmic string, and domain wall, and derive a new one. The dual formulation may be useful for developing the parametrized post Newtonian formalism in the theories of modified gravity that give rise to such scalar theories.

A class of diffeomorphism-invariant, physical observables, so-called astrometric observables, is introduced. A particularly simple example, the time delay, which expresses the difference between two initially synchronized proper time clocks in relative inertial motion, is analyzed in detail. It is found to satisfy some interesting inequalities related to the causal structure of classical Lorentzian spacetimes. Thus it can serve as a probe of causal structure and, in particular, of violations of causality. A quantum model of this observable as well as the calculation of its variance due to vacuum fluctuations in quantum linearized gravity are sketched. The question of whether the causal inequalities are still satisfied by quantized gravity, which is pertinent to the nature of causality in quantum gravity, is raised, but it is shown that perturbative calculations cannot provide a definite answer. Some potential applications of astrometric observables in quantum gravity are discussed.

We study conformally flat initial data for an arbitrary number of spinning black holes with exact analytic solutions to the momentum constraints constructed from a linear combination of the classical Bowen-York and conformal Kerr extrinsic curvatures. The solution leading to the largest intrinsic spin, relative to the Arnowitt-Deser-Misner (ADM) mass of the spacetime, ${ϵ}_S=S/M_{\mathrm{ADM}}^2$, is a superposition with relative weights of $\Lambda =0.783$ for conformal Kerr and $(1-\Lambda )=0.217$ for Bowen-York. In addition, we measure the spin relative to the initial horizon mass $M_{H_0}$, and find that the quantity $\chi =S/M_{H_0}^2$ reaches a maximum of ${\chi }^{\max }=0.9856$ for $\Lambda =0.753$. After equilibration, the final black-hole spin should lie in the interval $0.9324<{\chi }_{\mathrm{final}}<0.9856$. We perform full numerical evolutions to compute the energy radiated and the final horizon mass and spin. We find that the black hole settles to a final spin of ${\chi }_{\mathrm{final}}^{\max }=0.935$ when $\Lambda =0.783$. We also study the evolution of the apparent horizon structure of this maximal black hole in detail.

Dark matter in the form of Weakly Interacting Massive Particles (WIMPs) can be captured by the Sun and the Earth, sink to their cores, annihilate and produce neutrinos that can be searched for with neutrino telescopes. The calculation of the capture rates of WIMPs in the Sun and especially the Earth are affected by large uncertainties coming mainly from effects of the planets in the Solar System, reducing the capture rates by up to an order of magnitude (or even more in some cases). We show that the WIMPs captured by weak scatterings in the Sun also constitute an important bound WIMP population in the Solar System. Taking this population and its interplay with the population bound through gravitational diffusion into account cancel the planetary effects on the capture rates, and the capture essentially proceeds as if the Sun and the Earth were free in the galactic halo. The neutrino signals from the Sun and the Earth are thus significantly higher than claimed in the scenarios with reduced capture rates.

We investigate the constraining power of current and future Sunyaev-Zeldovich cluster surveys on the $f(R)$ gravity model. We use a Fisher matrix approach, adopt self-calibration for the mass-observable scaling relation, and evaluate constraints for the South Pole Telescope (SPT), Planck, SPT polarimeter (SPTpol), and Atacama Cosmology Telescope polarimeter (ACTpol) surveys. The modified gravity effects on the mass function, halo bias, matter power spectrum, and mass-observable relation are taken into account. We show that, relying on number counts only, the Planck cluster catalog is expected to reduce current upper limits by about a factor of 4, to ${\sigma }_{f_{R0}}=2\times {10}^{-5}$ (68% confidence level) while SPT, SPTpol, and ACTpol yield about $3\times {10}^{-5}$. Adding the cluster power spectrum further improves the constraints to ${\sigma }_{f_{R0}}=5\times {10}^{-6}$ for Planck and ${\sigma }_{f_{R0}}=2\times {10}^{-5}$ for SPTpol, pushing cluster constraints significantly beyond the limit where number counts have no constraining power due to the chameleon screening mechanism. Further, the combination of both observables breaks degeneracies, especially with the expansion history (effective dark energy density and equation of state). The constraints are only mildly worsened by the use of self-calibration but depend on the mass threshold and redshift coverage of the cluster samples.

We consider dark matter consisting of weakly interacting massive particles (WIMPs) and revisit in detail its thermal evolution in the early universe, with a particular focus on models where the annihilation rate is enhanced by the Sommerfeld effect. After chemical decoupling, or freeze-out, dark matter no longer annihilates but is still kept in local thermal equilibrium due to scattering events with the much more abundant standard model particles. During kinetic decoupling, even these processes stop to be effective, which eventually sets the scale for a small-scale cutoff in the matter density fluctuations. Afterwards, the WIMP temperature decreases more quickly than the heat bath temperature, which causes dark matter to reenter an era of annihilation if the cross-section is enhanced by the Sommerfeld effect. Here, we give a detailed and self-consistent description of these effects. As an application, we consider the phenomenology of simple leptophilic models that have been discussed in the literature and find that the relic abundance can be affected by as much two orders of magnitude or more. We also compute the mass of the smallest dark matter subhalos in these models and find it to be in the range $\mathcal{O}({10}^{-10}{M}_{\odot })-\mathcal{O}(10M_{\odot })$; even much larger cutoff values are possible if the WIMPs couple to force carriers lighter than about 100 MeV. We point out that a precise determination of the cutoff mass allows to infer new limits on the model parameters, in particular, from gamma-ray observations of galaxy clusters, that are highly complementary to existing constraints from $g-2$ or beam dump experiments.

The latest years have seen steady progresses in weakly interacting massive particle dark matter (DM) searches, with hints of possible signals suggested both in direct and indirect detection. Antiprotons play a key role in this context, since weakly interacting massive particle annihilations can be a copious source of antiprotons, and the antiproton flux from conventional astrophysical sources is predicted with fair accuracy and matches the measured cosmic ray (CR) spectrum very well. Using the publicly available dragon code, we reconsider antiprotons as a tool to set constraints on DM models; we compare against the most up-to-date $\overline{p}$ measurements, taking also into account the latest spectral information on the $p$ and He CR fluxes. In particular, we probe carefully the uncertainties associated to both standard astrophysical and DM originated antiprotons, by using a variety of distinctively different assumptions for the propagation of CRs and for the DM distribution in the Galaxy. We find that the impact of the astrophysical uncertainties on constraining the DM properties of a wide class of annihilating DM models can be much stronger, up to a factor of $\sim 50$, than the one due to uncertainties on the DM distribution ($\sim 2–6$). Remarkably, even reducing the uncertainties on the propagation parameters derived by local observables, nonlocal effects can change our predictions for the constraints even by 50%. Nevertheless, current $\overline{p}$ data can place tight constraints on DM models, excluding some of those suggested in connection with indirect and direct searches. Finally we discuss the impact of upcoming CR spectral data from the AMS-02 instrument on DM model constraints.

In this paper we reconsider the model of neutrino production during the “bright phase,” first suggested in 1977, in the light of modern understanding of both the role of Pop III stars and of acceleration of particles in supernova shocks. We concentrate on the production of cosmogenic ultrahigh energy neutrinos in supernova (SN) explosions that accompany the death of massive Population III stars. Protons are assumed to be accelerated at such SN shocks and produce neutrinos in collisions with CMB photons. In the calculations we deliberately use simplified assumptions which make the physical results transparent. Pop III stars, either directly or through their SN explosions, are assumed to be responsible for the reionization of the universe as observed by WMAP. Since the evolution of massive Pop III stars occurs on time scales much shorter than the Hubble time $H^{-1}$, we consider the burst of UHE proton production to occur at fixed redshift ($z_b=10$ and $z_b=20$), though more realistic models can easily be built. We discuss in some detail the problems involved in the formation of collisionless shocks in the early universe as well as the acceleration of charged particles in a medium that has potentially very low preexisting magnetization, if any at all. The composition of the accelerated particles in Pop III stars explosions is expected to be proton dominated, based upon the predictions of BBN and the Hydrogen-enhanced stellar-wind from primary Pop III stars. A simple calculation is presented to illustrate the fact that the diffuse neutrino flux from the bright phase burst is concentrated in a relatively narrow energy interval, centered at $E_{\nu }^c=7.5\times {10}^{15}(20/z_b{)}^2\mathrm{eV}$. The ${\nu }_{\mu }$ flux may be detectable by IceCube without violating the cascade upper limit and without exceeding the expected energetics of SNe associated with Pop III stars. A possible signature of the neutrino production from Pop III stars may be the detection of resonant neutrino events (${\overline{\nu }}_e+e^{-}\to W^{-}\to \mathrm{\text{hadrons}}$) at energy $E_0=6.3\times {10}^{15}\mathrm{eV}$. For the burst at $z_b=20$ and ${\overline{\nu }}_e$-flux at the cascade upper limit, the number of resonant events in IceCube may be as high as 10 events in 5 years of observations. These events have equal energies, $E=6.3\times {10}^{15}\mathrm{eV}$, in the form of e-m cascades. Taking into account the large uncertainties in the existing predictions of cosmogenic neutrino fluxes at $E>{10}^{15}\mathrm{eV}$, we argue that UHE neutrinos from the first stars might become one of the most reliable hopes for UHE neutrino astronomy.

The presence of light sterile neutrinos would strongly modify the energy spectrum of the tritium $\beta$ electrons. We perform an analysis of the KArlsruhe TRItium Neutrino (KATRIN) experiment’s sensitivity by scanning almost all the allowed region of neutrino mass-squared difference and mixing angles of the $3+1$ scenario. We consider the effect of the unknown absolute mass scale of active neutrinos on the sensitivity of KATRIN to the sterile neutrino mass. We show that after 3 years of data-taking, the KATRIN experiment can be sensitive to mixing angles as small as ${sin}^{2}2{\theta }_s\sim {10}^{-2}$. Particularly we show that for small mixing angles, ${sin}^{2}2{\theta }_s\lesssim 0.1$, the KATRIN experiment can give the strongest limit on active-sterile mass-squared difference.

Gauge-mediated models of supersymmetry breaking ($\cancel{\mathrm{SUSY}}$) often exhibit “gaugino screening,” where to leading order in $F$, gaugino masses are unaffected by higher-dimensional Kähler potential interactions between the $\cancel{\mathrm{SUSY}}$ spurion and the messengers. We provide a derivation of this phenomenon which uses the gaugino counterterm originally proposed in the context of anomaly mediation by Dine and Seiberg. We argue that this counterterm is present when there are nonzero messenger $F$-terms and it can cancel the leading order Feynman diagram contribution to the gaugino mass. We provide a nontrivial check of the regulator independence of our results by performing the computation using both dimensional reduction and Pauli-Villars. This analysis reconciles an apparent contradiction between diagrammatics and analytic continuation into superspace.

In this paper we investigate the influence of a constant external magnetic field on the finite-temperature phase structure and the chiral properties of a simplified lattice model for QCD. We assume an $SU(2)$ gauge symmetry and employ dynamical staggered fermions of identical mass without rooting, corresponding to $N_f=4$ flavors of identical electric charge. For fixed mass (given in lattice units) the critical temperature is seen to rise with the magnetic field strength. For three fixed $\beta$ values, selected such that we stay (i) within the chirally broken phase, (ii) within the transition region, or (iii) within the chirally restored phase, we study the approach to the chiral limit for various values of the magnetic field. Within the chirally broken (confinement) phase the chiral condensate is found to increase monotonically with a growing magnetic field strength. In the chiral limit the increase starts linear in agreement with a chiral model studied by Shushpanov and Smilga. Within the chirally restored (deconfinement) phase the chiral condensate tends to zero in the chiral limit, irrespective of the strength of the magnetic field.

We analyze the properties of the Aivazis-Collins-Olness-Tung (ACOT) scheme for heavy quark production and make use of the $\overline{\mathrm{MS}}$ massless results at next-to-next-to-leading order and ${\mathrm{N}}^3\mathrm{LO}$ for the structure functions $F_2$ and $F_L$ in neutral current deep-inelastic scattering to estimate the higher order corrections. For this purpose we decouple the heavy quark mass entering the phase space from the one entering the dynamics of the short distance cross section. We show numerically that the phase space mass is generally more important. Therefore, the dominant heavy quark mass effects at higher orders can be taken into account using the massless Wilson coefficients together with an appropriate slow-rescaling prescription implementing the phase space constraints. Combining the exact ACOT scheme at next-to-leading order with these expressions should provide a good approximation to the missing full calculation in the ACOT scheme at next-to-next-to-leading order and ${\mathrm{N}}^3\mathrm{LO}$.

It is widely believed that Lorentz symmetry of physical vacuum is broken near the Planck scale. Here we show that recently demonstrated “hyperbolic metamaterial” behavior of vacuum in a strong magnetic field provides us with an interesting analogy of the Planck-scale physics. As demonstrated by Chernodub, strong magnetic field forces vacuum to develop real condensates of electrically charged $\rho$ mesons, which form an anisotropic inhomogeneous superconducting state similar to Abrikosov vortex lattice. As far as electromagnetic field behavior is concerned, this hyperbolic metamaterial state of vacuum exhibits effective 3D Lorentz symmetry, which is broken at small scale (large momenta) due to spatial dispersion. Thus, an effective Lorentz symmetry-violating “Planck scale” may be introduced. Near the critical magnetic field this effective Planck scale is much larger than the metamaterial periodicity defined by the $\rho$ meson lattice. Similar to regular hyperbolic metamaterials, spatial dispersion of vacuum in a strong magnetic field leads to appearance of the “additional wave,” which manifests itself as a “heavy” extraordinary photon with an effective mass $\sim 2\mathrm{GeV}$.

In a hard-wall model of holographic QCD, we find that nonlinear boundary dynamics are required in order to maintain the correct pattern of explicit and spontaneous chiral symmetry breaking beyond leading order in the pion fields. With the help of a field redefinition, we relate the requisite nonlinear boundary conditions to a standard Sturm-Liouville system. Observables insensitive to the chiral limit receive only small corrections in the improved description, and classical calculations in the hard-wall model remain surprisingly accurate.

We measure the ${\Lambda }_b^0$ lifetime in the fully reconstructed decay ${\Lambda }_b^0\to J/\psi {\Lambda }^0$ using $10.4{\mathrm{fb}}^{-1}$ of $p\overline{p}$ collisions collected with the D0 detector at $\sqrt{s}=1.96\mathrm{TeV}$. The lifetime of the topologically similar decay channel $B^0\to J/\psi K_S^0$ is also measured. We obtain $\tau ({\Lambda }_b^0)=1.303\pm 0.075(\mathrm{stat})\pm 0.035(\mathrm{syst})\mathrm{ps}$ and $\tau (B^0)=1.508\pm 0.025(\mathrm{stat})\pm 0.043(\mathrm{syst})\mathrm{ps}$. Using these measurements, we determine the lifetime ratio of $\tau ({\Lambda }_b^0)/\tau (B^0)=0.864\pm 0.052(\mathrm{stat})\pm 0.033(\mathrm{syst})$.

We investigate a spatially flat Friedmann-Robertson-Walker universe that has an interacting dark matter, a modified holographic Ricci dark energy (MHRDE), plus a third, decoupled component that behaves as a radiation term. We consider a nonlinear interaction in the dark component densities and their derivatives up to second order. We apply the ${\chi }^2$ method to the observational Hubble data for constraining the cosmological parameters, and analyze the amount of dark energy in the radiation era for both MHRDE and holographic Ricci dark energy models. The former is consistent with the bound ${\Omega }_x(z\simeq 1100)<0.1$ reported for the behavior of dark energy at early times, while the latter does not fulfill it.

The assumptions that light propagates along null geodesics of the spacetime metric and the number of photons is conserved along the light path lead to the distance duality relation (DDR), $\eta =D_L(z)(1+z{)}^{-2}/D_A(z)=1$, with $D_L(z)$ and $D_A(z)$ the luminosity and angular diameter distances to a source at redshift $z$. In order to test the DDR, we follow the usual strategy comparing the angular diameter distances of a set of clusters, inferred from x-ray and radio data, with the luminosity distance at the same cluster redshift using the local regression technique to estimate $D_L(z)$ from a type Ia supernovae (SNeIa) Hubble diagram. In order to both strengthen the constraints on the DDR and get rid of the systematics related to the unknown cluster geometry, we also investigate the possibility to use baryon acoustic oscillations (BAO) to infer $D_A(z)$ from future BAO surveys. As a test case, we consider the proposed Euclid mission investigating the precision that can be afforded on $\eta (z)$ from the expected SNeIa and BAO data. We find that the combination of BAO and the local regression coupled allows one to reduce the errors on ${\eta }_a=d\eta /dz{|}_{z=0}$ by a factor 2 if one ${\eta }_0=\eta (z=0)=1$ is forced and future data are used. On the other hand, although the statistical error on ${\eta }_0$ is not significantly reduced, the constraints on this quantity will be nevertheless ameliorated thanks to the reduce impact of systematics.