We propose a resonant leptogenesis scenario in a $U(1{)}_{B-L}$ gauge extension of the standard model to generate large lepton asymmetries for cosmological baryon asymmetry and dark matter. After the $B-L$ number is spontaneously broken, the inflaton can pick up a small vacuum expectation value for the mass splits of three pairs of quasidegenerately heavy Majorana neutrinos and the masses of three sterile neutrinos. With thermal mass effects of sphalerons, the observed small baryon asymmetry can be converted from large lepton asymmetries of individual flavors, although total lepton asymmetry is assumed zero. The mixing between sterile and active neutrinos is elegantly suppressed by the heavy Majorana neutrinos. Before the active neutrinos start their strong flavor conversions, the sterile neutrinos as warm dark matter can be produced by resonant active-sterile neutrino oscillations to reconcile x-ray and Lyman-$\alpha$ bounds. Small neutrino masses are naturally realized by seesaw contributions from the heavy Majorana neutrinos and the sterile neutrinos.

We discuss the effects of one additional sterile neutrino at the Neutrino Factory. Compared to earlier analyses, which have been motivated by Liquid Scintillator Neutrino Detector (LSND) results, we do not impose any constraint on the additional mass squared splitting. This means that the additional mass eigenstate could, with small mixings, be located among the known ones, as it is suggested by the recent analysis of cosmological data. We use a self-consistent framework at the Neutrino Factory without any constraints on the new parameters. We demonstrate for a combined short and long baseline setup that near detectors can provide the expected sensitivity at the LSND-motivated $\Delta m_{41}^2$-range, while some sensitivity can also be obtained in the region of the atmospheric mass splitting from the long baselines. We point out that limits on such very light sterile neutrinos may also be obtained from a reanalysis of atmospheric and solar neutrino oscillation data, as well as from supernova neutrino observations. In the second part of the analysis, we compare our sensitivity with the existing literature using additional assumptions, such as $|\Delta m_{41}^2|\gg |\Delta m_{31}^2|$, leading to averaging of the fast oscillations in the far detectors. We demonstrate that while the Neutrino Factory has excellent sensitivity compared to existing studies using similar assumptions, one has to be very careful interpreting these results for a combined short and long baseline setup where oscillations could occur in the near detectors. We also test the impact of additional ${\nu }_{\tau }$ detectors at the short and long baselines, and we do not find a substantial improvement of the sensitivities.

We study a brane configuration of $D4$-branes and $NS5$-branes in weakly coupled type IIA string theory, which describes in a particular limit $d=4$ $\mathcal{N}=1$ $SU(N+p)$ supersymmetric QCD with $2N$ flavors and a quartic superpotential. We describe the geometric realization of the supersymmetric vacuum structure of this gauge theory. We focus on the confining vacua of the gauge theory, whose holographic description is given by the MQCD brane configuration in the near-horizon geometry of $N$ $D4$-branes. This description, which gives an embedding of MQCD into a field theory decoupled from gravity, is valid for $1\ll p\ll N$, in the limit of large five-dimensional ‘t Hooft couplings for the color and flavor groups. We analyze various properties of the theory in this limit, such as the spectrum of mesons, the finite temperature behavior, and the quark-antiquark potential. We also discuss the same brane configuration on a circle, where it gives a geometric description of the moduli space of the Klebanov-Strassler cascading theory, and some nonsupersymmetric generalizations.

We discuss the mass ejection mechanism induced by diffusion of neutrino during the early stage of the protoneutron star cooling. A dynamical calculation is employed in order to determine the amount of matter ejected and the remnant compact object mass. An equation of state considering hadronic and quark phases for the stellar dense matter was used to solve the whole time evolution of the system during the cooling phase. The initial neutrino population was obtained by considering beta equilibrium in the dense stellar matter with confined neutrinos, in the very early period of the deleptonic stage of the nascent pulsar. For specified initial configurations of the protoneutron star, we solve numerically the set of equations of motion together with neutrino diffusion through the dense stellar medium.

The goal of much research in relativity is to understand gravitational waves generated by a strong-field dynamical spacetime. Quantities of particular interest for many calculations are the Weyl scalar ${\psi }_4$, which is simply related to the flux of gravitational waves far from the source, and the flux of energy carried to distant observers, $\dot{E}$. Conservation laws guarantee that, in asympotically flat spacetimes, ${\psi }_4\propto 1/r$ and $\dot{E}\propto 1/r^2$ as $r\to \infty$. Most calculations extract these quantities at some finite extraction radius. An understanding of finite radius corrections to ${\psi }_4$ and $\dot{E}$ allows us to more accurately infer their asymptotic values from a computation. In this paper, we show that, if the final state of the system is a black hole, then the leading correction to ${\psi }_4$ is $\mathcal{O}(1/r^3)$, and that to the energy flux is $\mathcal{O}(1/r^4)$—not $\mathcal{O}(1/r^2)$ and $\mathcal{O}(1/r^3)$, as one might naively guess. Our argument only relies on the behavior of the curvature scalars for black hole spacetimes. Using black hole perturbation theory, we calculate the corrections to the leading falloff, showing that it is quite easy to correct for finite extraction radius effects.

Within linearized perturbation theory, black holes decay to their final stationary state through the well-known spectrum of quasinormal modes. Here we numerically study whether nonlinearities change this picture. For that purpose we study the ringdown frequencies of gauge-invariant second-order gravitational perturbations induced by self-coupling of linearized perturbations of Schwarzschild black holes. We do so through high-accuracy simulations in the time domain of first and second-order Regge-Wheeler-Zerilli type equations, for a variety of initial data sets. We consider first-order even-parity ($\ell =2$, $m=\pm 2$) perturbations and odd-parity ($\ell =2$, $m=0$) ones, and all the multipoles that they generate through self-coupling. For all of them and all the initial data sets considered we find that—in contrast to previous predictions in the literature—the numerical decay frequencies of second-order perturbations are the same ones of linearized theory, and we explain the observed behavior. This would indicate, in particular, that when modeling or searching for ringdown gravitational waves, appropriately including the standard quasinormal modes already takes into account nonlinear effects.

We study the density perturbation by a curvaton with a double well potential and give analytical expressions for the observables such as nonlinear parameters $f_{\mathrm{NL}}$, $g_{\mathrm{NL}}$ and tensor-to-scalar ratio $r_T$ with emphasizing the differences from the simple quadratic potential. We show that the level of non-Gaussianity and the tensor-to-scalar ratio depends crucially on the reheating temperature as well as the curvaton self-coupling constant for a given initial amplitude of the curvaton. We find that for a large initial field the nonlinear parameters $f_{\mathrm{NL}}$ can be $10–20$ and the gravitational wave background also is observable in the Planck satellite.

We study primordial fluctuations generated during inflation in a class of models motivated by the DBI Galileons, which are extensions of the DBI action that yield second-order field equations. This class of models generalizes the DBI Galileons in a similar way with $K$ inflation. We calculate the primordial non-Gaussianity from the bispectrum of the curvature perturbations at leading order in the slow-varying approximations. We show that the estimator for the equilateral-type non-Gaussianity, $f_{\mathrm{NL}}^{\mathrm{equil}}$, can be applied to measure the amplitude of the primordial bispectrum even in the presence of the Galileon-like term although it gives a slightly different momentum dependence from $K$-inflation models. For the DBI Galileons, we find $-0.32/c_s^2<f_{\mathrm{NL}}^{\mathrm{equil}}<-0.16/c_s^2$ and large primordial non-Gaussianities can be obtained when $c_s$ is much smaller than 1 as in the usual DBI inflation. In $G$-inflation models, where a de Sitter solution is obtained without any potentials, the nonlinear parameter is given by $f_{\mathrm{NL}}^{\mathrm{equil}}=4.62r^{-2/3}$, where $r$ is the tensor to scalar ratio, giving a stringent constraint on the model.

Scenarios where gravitinos with GeV masses makeup dark matter are known to be in tension with high reheating temperatures, as required by e.g. thermal leptogenesis. This tension comes from the longevity of the NLSPs (next-to-lightest supersymmetric particle), which can destroy the successful predictions of the standard primordial nucleosynthesis. However, a small violation of matter parity can open new decay channels for the NLSP, avoiding the BBN (standard primordial nucleosynthesis) problems, while being compatible with experimental cosmic-ray constraints. In this paper, we propose a model where matter parity, which we assume to be embedded in the $\mathrm{U}(1{)}_{B-L}$ gauge symmetry, is broken dynamically in a hidden sector at low-scales. This can naturally explain the smallness of the matter parity breaking in the visible sector. We discuss the dynamics of the corresponding pseudo Nambu-Goldstone modes of $B-L$ breaking in the hidden sector, and we comment on typical cosmic-ray and collider signatures in our model.

Central to the gravitational wave detection problem is the challenge of separating features in the data produced by astrophysical sources from features produced by the detector. Matched filtering provides an optimal solution for Gaussian noise, but in practice, transient noise excursions or “glitches” complicate the analysis. Detector diagnostics and coincidence tests can be used to veto many glitches which may otherwise be misinterpreted as gravitational wave signals. The glitches that remain can lead to long tails in the matched filter search statistics and drive up the detection threshold. Here we describe a Bayesian approach that incorporates a more realistic model for the instrument noise allowing for fluctuating noise levels that vary independently across frequency bands, and deterministic glitch fitting using wavelets as glitch templates, the number of which is determined by a transdimensional Markov chain Monte Carlo algorithm. We demonstrate the method’s effectiveness on simulated data containing low amplitude gravitational wave signals from inspiraling binary black-hole systems, and simulated nonstationary and non-Gaussian noise comprised of a Gaussian component with the standard LIGO/Virgo spectrum, and injected glitches of various amplitude, prevalence, and variety. Glitch fitting allows us to detect significantly weaker signals than standard techniques.

We investigate the cosmic age problem associated with 9 extremely old globular clusters in M31 galaxy and 1 very old high-$z$ quasar automatic plate-measuring machine $08279+5255$ at $z=3.91$. These 9 globular clusters have not been used to study the cosmic age problem in the previous literature. By evaluating the age of the Universe in the $\Lambda$ cold dark matter model with the observational constraints from the Type Ia supernovae, the baryon acoustic oscillations, the cosmic microwave background, and the independent $H_0$ measurements, we find that the existence of 5 globular clusters and 1 high-$z$ quasar are in tension (over $2\sigma$ confidence level) with the current cosmological observations. So if the age estimates of these objects are correct, the cosmic age puzzle still remains in the standard cosmology. Moreover, we extend our investigations to the cases of the interacting dark energy models. It is found that although the introduction of the interaction between dark sectors can give a larger cosmic age, the interacting dark energy models still have difficulty to pass the cosmic age test.

The annihilation of proton and antiproton to an electron-positron pair, including radiative corrections due to the emission of virtual and real photons is considered. The results are generalized to leading and next-to leading approximations. The relevant distributions are derived and numerical applications are given in the kinematical range accessible to the PANDA experiment at the FAIR facility.

Two-body hadronic weak decays of $B_c$ meson emitting pseudoscalar and heavy scalar mesons are investigated using the Spectator Quark Model. Decay amplitudes are obtained using the factorization scheme; consequently, branching ratios are predicted in the Isgur-Scora-Grinstein-Wise (ISGW II) model.

The semihadronic tau decay width allows a clean extraction of the strong coupling constant at low energies. We present a modification of the standard “contour-improved” method based on a derivative expansion of the Adler function. The new approach has some advantages compared to contour-improved perturbation theory. The renormalization scale dependence is weaker by more than a factor of 2 and the last term of the expansion is reduced by about 10%, while the renormalization scheme dependence remains approximately equal. The extracted QCD coupling at the tau mass scale is by 2% lower than the contour-improved value. We find ${\alpha }_s(M_Z^2)=0.1211\pm 0.0010$.

The KamLAND and Borexino experiments have detected electron antineutrinos produced in the decay chains of natural thorium and uranium (Th and U geoneutrinos). We analyze the energy spectra of current geoneutrino data in combination with solar and long-baseline reactor neutrino data, with marginalized three-neutrino oscillation parameters. We consider the case with unconstrained Th and U event rates in KamLAND and Borexino, as well as cases with fewer degrees of freedom, as obtained by successively assuming for both experiments a common Th/U ratio, a common scaling of $\mathrm{Th}+\mathrm{U}$ event rates, and a chondritic Th/U value. In combination, KamLAND and Borexino can reject the null hypothesis (no geoneutrino signal) at $5\sigma$. Interesting bounds or indications emerge on the $\mathrm{Th}+\mathrm{U}$ geoneutrino rates and on the Th/U ratio, in broad agreement with typical Earth model expectations. Conversely, the results disfavor the hypothesis of a georeactor in the Earth’s core, if its power exceeds a few TW. The interplay of KamLAND and Borexino geoneutrino data is highlighted.

New exact asymptotically flat solutions of five-dimensional Einstein equations with horizon are found to describe multidimensional black stars generated by matter on the brane, conceivably on high energy colliders. The five-dimensional space-time is realized as an orbifold against reflection of a special extra-space coordinate and matter on the brane is induced by tailoring of the five-dimensional Schwarzschild-Tangherlini black hole metric.

In this article, we give a full description of the dynamics of the flat anisotropic ($4+1$)-dimensional cosmological model in the presence of both Gauss-Bonnet and Einstein contributions. This is the first complete description of this model with both terms taken into account. Our data is obtained using the numerical analysis, though, we use analytics to explain some features of the results obtained, and the same analytics could be applied to higher-dimensional models with higher-order Lovelock corrections. Firstly, we investigate the vacuum model and give a description of all regimes; then, we add a matter source in the form of a perfect fluid and study the influence the matter exerts upon the dynamics. Thus, we give a description of matter regimes as well. Additionally, we demonstrate that the presence of matter not only improves the situation with a smooth transition between the standard singularity and the Kasner regime, but also brings additional regimes and even partially erases the boundaries between different regimes inside the same triplet. Finally, we discuss the numerical and analytical results obtained and their generalization to the higher-order models with an even number of spatial dimensions.

The spherical collapse model is often used to follow the evolution of overdensities into the nonlinear regime. We describe the correct approach to be used in coupled dark energy cosmologies, where a fifth force, different from gravity and mediated by the dark energy scalar field, influences the collapse. We reformulate the spherical collapse description by deriving it directly from the set of nonlinear hydrodynamical Navier-Stokes equations. By comparing with the corresponding relativistic equations, we show how the fifth force should be taken into account within the spherical collapse picture and clarify the problems arising when an inhomogeneous scalar field is considered within a spherical collapse picture. We then apply our method to the case of coupled quintessence, where the fifth force acts among cold dark matter particles, and to growing neutrino quintessence, where the fifth force acts between neutrinos. Furthermore, we review this method within standard cosmologies and apply our analysis to minimally coupled quintessence. We also check past results for early dark energy parametrizations.

It has recently been pointed out that the spinning Kerr black hole with maximal spin could act as a particle collider with arbitrarily high center-of-mass energy. In this paper, we will extend the result to the charged spinning black hole, the Kerr-Newman black hole. The center-of-mass energy of collision for two uncharged particles falling freely from rest at infinity depends not only on the spin $a$ but also on the charge $Q$ of the black hole. We find that an unlimited center-of-mass energy can be approached with the conditions: (1) the collision takes place at the horizon of an extremal black hole; (2) one of the colliding particles has critical angular momentum; (3) the spin $a$ of the extremal black hole satisfies $\frac{1}{\sqrt{3}}\le \frac{a}{M}\le 1$, where $M$ is the mass of the Kerr-Newman black hole. The third condition implies that to obtain an arbitrarily high energy, the extremal Kerr-Newman black hole must have a large value of spin, which is a significant difference between the Kerr and Kerr-Newman black holes. Furthermore, we also show that, for a near-extremal black hole, there always exists a finite upper bound for center-of-mass energy, which decreases with the increase of the charge $Q$.

We present the first astrophysical measurement of the pressure of cold matter above nuclear saturation density, based on recently determined masses and radii of three neutron stars. The pressure at higher densities is below the predictions of equations of state that account only for nucleonic degrees of freedom, and thus present a challenge to the microscopic theory of neutron star matter.