In order to keep pace with the increasing data quality of astronomical surveys the observed source redshift has to be modeled beyond the well-known Doppler contribution. In this article I want to examine the gauge issue that is often glossed over when one assigns a perturbed redshift to simulated data generated with a Newtonian $N$-body code. A careful analysis reveals the presence of a correction term that has so far been neglected. It is roughly proportional to the observed length scale divided by the Hubble scale and therefore suppressed inside the horizon. However, on gigaparsec scales it can be comparable to the gravitational redshift and hence amounts to an important relativistic effect.

QCD monopoles are magnetically charged quasiparticles whose Bose-Einstein condensation (BEC) at $T<T_c$ creates electric confinement and flux tubes. The “magnetic scenario” of QCD proposes that scattering on the noncondensed component of the monopole ensemble at $T>T_c$ is responsible for the unusual kinetic properties of quark-gluon plasma. In this paper, we study the contribution of the monopoles to jet quenching phenomenon, using the Baier-Dokshitzer-Mueller-Peigne-Schiff framework and hydrodynamic backgrounds. In the lowest order for cross sections, we calculate the nuclear modification factor, $R_{\mathrm{AA}}$, and azimuthal anisotropy, $v_2$, of jets, as well as the dijet asymmetry, $A_j$, and compare those to the available data. We find relatively good agreement with experiment when using realistic hydrodynamic backgrounds. In addition, we find that event-by-event fluctuations are not necessary to reproduce $R_{\mathrm{AA}}$ and $v_2$ data, but play a role in $A_j$. Since the monopole-induced effects are maximal at $T\approx T_c$, we predict that their role should be significantly larger, relative to quarks and gluons, at lower RHIC energies.

We explore the LHC reach on beyond-the-standard model (BSM) particles $X$ associated with a new strong force in a hidden sector. We focus on the motivated scenario where the SM and hidden sectors are connected by fermionic mediators ${\psi }^{+,0}$ that carry SM electroweak charges. The most promising signal is the Drell-Yan production of a ${\psi }^{\pm }{\overline{\psi }}^0$ pair, which forms an electrically charged vector bound state ${\mathrm{\Upsilon }}^{\pm }$ due to the hidden force and later undergoes resonant annihilation into $W^{\pm }X$. We analyze this final state in detail in the cases where $X$ is a real scalar $\varphi$ that decays to $b\overline{b}$, or a dark photon ${\gamma }_d$ that decays to dileptons. For prompt $X$ decays, we show that the corresponding signatures can be efficiently probed by extending the existing ATLAS and CMS diboson searches to include heavy resonance decays into BSM particles. For long-lived $X$, we propose new searches where the requirement of a prompt hard lepton originating from the $W$ boson ensures triggering and essentially removes any SM backgrounds. To illustrate the potential of our results, we interpret them within two explicit models that contain strong hidden forces and electroweak-charged mediators, namely $\lambda$-supersymmetry (SUSY) and non-SUSY ultraviolet extensions of the twin Higgs model. The resonant nature of the signals allows for the reconstruction of the mass of both ${\mathrm{\Upsilon }}^{\pm }$ and $X$, thus providing a wealth of information about the hidden sector.

We present lattice results for the isovector unpolarized parton distribution with nonperturbative regularization-invariant momentum-subtraction scheme (RI/MOM) renormalization on the lattice. In the framework of large-momentum effective field theory (LaMET), the full Bjorken-$x$ dependence of a momentum-dependent quasidistribution is calculated on the lattice and matched to the ordinary light cone parton distribution at one-loop order, with power corrections included. The important step of RI/MOM renormalization that connects the lattice and continuum matrix elements is detailed in this paper. A few consequences of the results are also addressed here.

In the spirit of Mueller-Navelet dijet production, we propose and study the inclusive production of a forward $J/\psi$ and a very backward jet at the LHC as an observable to reveal high-energy resummation effects à la Balitsky, Fadin, Kuraev, Lipatov. We obtain several predictions, which are based on the various mechanisms discussed in the literature to describe the production of the $J/\psi$, namely, nonrelativistic QCD singlet and octet contributions, and the color evaporation model.

We consider the limit $a\to \infty$ of the Kerr–de Sitter spacetime. The spacetime is a Petrov type-D solution of the vacuum Einstein field equations with a positive cosmological constant $\mathrm{\Lambda }$, vanishing Mars-Simon tensor and conformally flat $ℐ$. It possesses an Abelian 2-dimensional group of symmetries whose orbits are spacelike or timelike in different regions, and it includes, as a particular case, de Sitter spacetime. The global structure of the solution is analyzed in detail, with particular attention to its Killing horizons: they are foliated by noncompact marginally trapped surfaces of finite area, and one of them “touches” the curvature singularity, which resembles a null 2-dimensional surface. Outside the region between these horizons there exist trapped surfaces that again are noncompact. The solution contains, apart from $\mathrm{\Lambda }$, a unique free parameter which can be related to the angular momentum of the nonsingular horizon in a precise way. A maximal extension of the (axis of the) spacetime is explicitly built. We also analyze the structure of $ℐ$, whose topology is ${\mathbb{R}}^3$.

In five dimensions, we consider a model described by the Einstein gravity with a source given by a scalar field and various Abelian gauge fields with dilatoniclike couplings. For this model, we are able to construct two dyonic black holes whose three-dimensional horizons are modeled by two nontrivial homogeneous Thurston’s geometries. The dyonic solutions are of Lifshitz type with an arbitrary value of the dynamical exponent. In fact, the first gauge field ensures the anisotropy asymptotic while the remaining Abelian fields sustain the electric and magnetic charges. Using the Hamiltonian formalism, the mass, the electric, and magnetic charges are explicitly computed. Interestingly enough, the dyonic solutions behave like Chern-Simons vortices in the sense that their electric and magnetic charges turn to be proportional. The extension with an hyperscaling violating factor is also scrutinized where we notice that for specific values of the violating factor, purely magnetic solutions are possible.

We study the evolution of gravitational waves (GWs) during and after inflation as well as the resulting observational consequences in a Lorentz-violating massive gravity theory with one scalar (inflaton) and two tensor degrees of freedom. We consider two explicit examples of the tensor mass $m_g$ that depends either on the inflaton field $\varphi$ or on its time derivative $\dot{\varphi }$, both of which lead to parametric excitations of GWs during reheating after inflation. The first example is Starobinsky’s $R^2$ inflation model with a $\varphi$-dependent $m_g$, and the second is a low energy–scale inflation model with a $\dot{\varphi }$-dependent $m_g$. We compute the energy density spectrum ${\mathrm{\Omega }}_{\mathrm{GW}}(k)$ today of the GW background. In the Starobinsky’s model, we show that the GWs can be amplified up to the detectable ranges of both cosmic microwave background and DECi-hertz Interferometer Gravitational wave Observatory, but the bound from the big bang nucleosynthesis is quite tight to limit the growth. In low-scale inflation with a fast transition to the reheating stage driven by the potential $V(\varphi )=M^2{\varphi }^2/2$ around $\varphi \approx M_{\mathrm{pl}}$ (where $M_{\mathrm{pl}}$ is the reduced Planck mass), we find that the peak position of ${\mathrm{\Omega }}_{\mathrm{GW}}(k)$ induced by the parametric resonance can reach the sensitivity region of advanced LIGO for the Hubble parameter of order 1 GeV at the end of inflation. Thus, our massive gravity scenario offers exciting possibilities for probing the physics of primordial GWs at various different frequencies.

The problem of Jeans gravitational instability is investigated for static and expanding universes within the context of the five and thirteen field theories which account for viscous and thermal effects. For the five-field theory a general dispersion relation has been derived with the help of relevant linearized perturbation equations, showing that the shear viscosity parameter alters the propagating modes for large and small wavelengths. The behavior of density and temperature contrasts are analyzed for the hard-sphere model in detail. In the small wavelengths regime, increasing the amount of shear viscosity into the system forces the harmonic perturbations to damp faster, however, in the opposite limit larger values of shear viscosity lead to smaller values of density and temperature contrasts. We also consider the hyperbolic case associated with the thirteen-field theory which involves two related parameters, namely the shear viscosity and the collision frequency, the last one is due to the production terms which appear in the Grad method. The dispersion relation becomes a polynomial in the frequency with two orders higher in relation to the five-field theory, indicating that the effects associated with the shear viscosity and heat flux are nontrivial. The profile of Jeans mass in terms of the temperature and number density is explored by contrasting with several data of molecular clouds. Regarding the dynamical evolution of the density, temperature, stress and heat flux contrasts for a universe dominated by pressureless matter, we obtain also damped harmonic waves for small wavelengths. In the case of large wavelengths, the density and temperature contrasts grow with time (due to the Jeans mechanism) while the stress and heat flux contrasts heavily decay with time. For an expanding universe, the Jeans mass and Jeans length are obtained and their physical consequences are explored.

We present a new measurement of the kinetic Sunyaev-Zeldovich effect (kSZ) using Planck cosmic microwave background (CMB) and Baryon Oscillation Spectroscopic Survey (BOSS) data. Using the “LowZ North/South” galaxy catalogue from BOSS DR12, and the group catalogue from BOSS DR13, we evaluate the mean pairwise kSZ temperature associated with BOSS galaxies. We construct a “Central Galaxies Catalogue” (CGC) which consists of isolated galaxies from the original BOSS data set, and apply the aperture photometry (AP) filter to suppress the primary CMB contribution. By constructing a halo model to fit the pairwise kSZ function, we constrain the mean optical depth to be $\overline{\tau }=(0.53\pm 0.32)\times {10}^{-4}(1.65\sigma )$ for LowZ North CGC, $\overline{\tau }=(0.30\pm 0.57)\times {10}^{-4}(0.53\sigma )$ for LowZ South CGC, and $\overline{\tau }=(0.43\pm 0.28)\times {10}^{-4}(1.53\sigma )$ for DR13 Group. In addition, we vary the radius of the AP filter and find that the AP size of 7 arcmin gives the maximum detection for $\overline{\tau }$. We also investigate the dependence of the signal with halo mass and find $\overline{\tau }=(0.32\pm 0.36)\times {10}^{-4}(0.8\sigma )$ and $\overline{\tau }=(0.67\pm 0.46)\times {10}^{-4}(1.4\sigma )$ for DR13 Group with halo mass restricted to, respectively, less and greater than its median halo mass, $10^{12}{h}^{-1}{\mathrm{M}}_{\odot }$. For the LowZ North CGC sample restricted to $M_{\mathrm{h}}\gtrsim {10}^{14}{h}^{-1}{\mathrm{M}}_{\odot }$ there is no detection of the kSZ signal because these high mass halos are associated with the high-redshift galaxies of the LowZ North catalogue, which have limited contribution to the pairwise kSZ signals.

Compensated isocurvature perturbations (CIPs) are opposite spatial fluctuations in the baryon and dark matter (DM) densities. They arise in the curvaton model and some models of baryogenesis. While the gravitational effects of baryon fluctuations are compensated by those of DM, leaving no observable impacts on the cosmic microwave background (CMB) at first order, they modulate the sound horizon at recombination, thereby correlating CMB anisotropies at different multipoles. As a result, CIPs can be reconstructed using quadratic estimators similarly to CMB detection of gravitational lensing. Because of these similarities, however, the CIP estimators are biased with lensing contributions that must be subtracted. These lensing contributions for CMB polarization measurement of CIPs are found to roughly triple the noise power of the total CIP estimator on large scales. In addition, the cross power with temperature and $E$-mode polarization are contaminated by lensing-ISW (integrated Sachs-Wolfe) correlations and reionization-lensing correlations respectively. For a cosmic-variance-limited temperature and polarization experiment measuring out to multipoles $l_{\max }=2500$, the lensing noise raises the detection threshold by a factor of 1.5, leaving a $2.7\sigma$ detection possible for the maximal CIP signal in the curvaton model.

Gravitational wave astronomy is just beginning, after the recent success of the four direct detections of binary black hole (BBH) mergers and the first observation from a binary neutron star inspiral, with the expectation of many more events to come. Given the possibility to detect waves from not exactly modeled astrophysical processes, it is fundamental to be ready to calculate the polarization waveforms in the case of searches using nontemplate algorithms. In such a case, the waveform polarizations are the only quantities that contain direct information about the generating process. We present the performance of a new valuable tool to estimate the inverse solution of gravitational wave transient signals, starting from the analysis of the signal properties of a nontemplate algorithm that is open to a wider class of gravitational signals not covered by template algorithms. We highlight the contributions to the wave polarization associated with the detector response, the sky localization, and the polarization angle of the source. In this paper we present the performances of such a method and its implications by using two main classes of transient signals, resembling the limiting case for most simple and complicated morphologies. The performances are encouraging for the tested waveforms: the correlation between the original and the reconstructed waveforms spans from better than 80% for simple morphologies to better than 50% for complicated ones. For a nontemplate search these results can be considered satisfactory to reconstruct the astrophysical progenitor.

We examine the role of hyperons in a neutron star based on the relativistic mean field approach. For nuclear matter below 1.5 times the normal nuclear density we constrain the model parameters by using the symmetric nuclear matter properties and theoretical investigations for neutron matter in the literature. We then extend the model to higher densities by including hyperons and isoscalar vector mesons that contain strangeness degree of freedom. We confirm that the $\varphi$ meson induces a $\mathrm{\Lambda }$ repulsive force and hardens the equation of state. The hardening arising from the $\varphi$ meson compensates the softening from the existence of hyperons. The flavor SU(3) and spin-flavor SU(6) relations are examined as well. We found that the coupling constants fitted by neutron matter properties could yield high enough maximum mass of a neutron star and the obtained results satisfy both the mass and radius constraints. The onset of the hyperon direct Urca process in neutron stars is also investigated using our parametrization.

The physics potential of EDELWEISS detectors for the search of low-mass weakly interacting massive particles (WIMPs) is studied. Using a data-driven background model, projected exclusion limits are computed using frequentist and multivariate analysis approaches, namely, profile likelihood and boosted decision tree. Both current and achievable experimental performances are considered. The optimal strategy for detector optimization depends critically on whether the emphasis is put on WIMP masses below or above $\sim 5\mathrm{GeV}/{\mathrm{c}}^2$. The projected sensitivity for the next phase of the EDELWEISS-III experiment at the Modane Underground Laboratory (LSM) for low-mass WIMP search is presented. By 2018 an upper limit on the spin-independent WIMP-nucleon cross section of ${\sigma }_{\mathrm{SI}}=7\times {10}^{-42}{\mathrm{cm}}^2$ is expected for a WIMP mass in the range $2–5\mathrm{GeV}/{\mathrm{c}}^2$. The requirements for a future hundred-kilogram-scale experiment designed to reach the bounds imposed by the coherent scattering of solar neutrinos are also described. By improving the ionization resolution down to $50{\mathrm{eV}}_{ee}$, we show that such an experiment installed in an even lower background environment (e.g., at SNOLAB) together with an exposure of $1000\mathrm{kg}·\mathrm{yr}$, should allow us to observe about 80 ${}^8\mathrm{B}$ neutrino events after discrimination.

We compute the decay rates for the processes $Z\to V+\gamma$, where $Z$ is the $Z$-boson, $\gamma$ is the photon, and $V$ is one of the vector quarkonia $J/\psi$ or $\mathrm{\Upsilon }(nS)$, with $n=1$, 2, or 3. Our computations include corrections through relative orders ${\alpha }_s$ and $v^2$ and resummations of logarithms of $m_Z^2/m_Q^2$, to all orders in ${\alpha }_s$, at next-to-leading-logarithmic accuracy. ($v$ is the velocity of the heavy quark $Q$ or the heavy antiquark $\overline{Q}$ in the quarkonium rest frame, and $m_Z$ and $m_Q$ are the masses of $Z$ and $Q$, respectively.) Our calculations are the first to include both the order-${\alpha }_s$ correction to the light-cone distributions amplitude and the resummation of logarithms of $m_Z^2/m_Q^2$ and are the first calculations for the $\mathrm{\Upsilon }(2S)$ and $\mathrm{\Upsilon }(3S)$ final states. The resummations of logarithms of $m_Z^2/m_Q^2$ that are associated with the order-${\alpha }_s$ and order-$v^2$ corrections are carried out by making use of the Abel-Padé method. We confirm the analytic result for the order-$v^2$ correction that was presented in a previous publication, and we correct the relative sign of the direct and indirect amplitudes and some choices of scales in that publication. Our branching fractions for $Z\to J/\psi +\gamma$ and $Z\to \mathrm{\Upsilon }(1S)+\gamma$ differ by $2.0\sigma$ and $-4.0\sigma$, respectively, from the branching fractions that are given in the most recent publication on this topic (in units of the uncertainties that are given in that publication). However, we argue that the uncertainties in the rates are underestimated in that publication.

We revisit the description of the Pomeron within the effective string theory of QCD. Using a string duality relation, we show how the static potential maps onto the high-energy scattering amplitude that exhibits the Pomeron behavior. Besides the Pomeron intercept and slope, new additional terms stemming from the higher order string corrections are shown to affect both the growth of the nucleon’s size at high energies and its profile in impact parameter space. The stringy description also allows for an odderon that only disappears in critical dimension. Some of the Pomeron’s features that emerge within the effective string description can be studied at the future EIC collider.

We demonstrate that rare decays of the Standard Model $Z$ boson can be used to discover and characterize the nature of new hidden-sector particles. We propose new searches for these particles in soft, high-multiplicity leptonic final states at the Large Hadron Collider. The proposed searches are sensitive to low-mass particles produced in $Z$ decays, and we argue that these striking signatures can shed light on the hidden-sector couplings and mechanism for mass generation.

We show that the decay rates of the Higgs boson to a pseudoscalar quarkonium and a pair of leptons, $h\to P{\ell }^{+}{\ell }^{-}$ ($P\in \{{\eta }_c,{\eta }_b\}$), can be substantially enhanced in a scenario with two Higgs doublets with a softly broken ${\mathbb{Z}}_2$ symmetry [two Higgs doublet model (2HDM)] when the $CP$-odd Higgs $A$ is light, i.e. $m_A\lesssim m_h$. Depending on the type of 2HDM the enhancement of $\mathcal{B}(h\to {\eta }_{c,b}{\tau }^{+}{\tau }^{-})$ with respect to its Standard Model value can be an order of magnitude larger, i.e. $\mathcal{O}({10}^{-6}–{10}^{-5})$. The decays $h\to P{\ell }^{+}{\ell }^{-}$ could therefore provide an efficient channel to investigate the presence of a light $CP$-odd Higgs $A$ and help to disentangle among various 2HDM scenarios.

The decay width of $N(1535)\to N\eta$ is as large as that of $N(1535)\to N\pi$. This is in evident conflict with simple expectations based on flavor symmetry and phase space. Similarly, the decay width of $\mathrm{\Lambda }(1670)\to \mathrm{\Lambda }(1116)\eta$ is larger than predicted by flavor symmetry. In this work, we propose that the axial $U(1{)}_A$ anomaly is responsible for an enhanced coupling of (some) excited baryons to the $\eta$ meson. We test this idea by including a new, chirally symmetric but $U(1{)}_A$ anomalous, term in an effective hadronic model describing baryons and their chiral partners in the mirror assignment. This term enhances the decay of the chiral partners into baryons and an $\eta$ meson, such as $N(1535)\to N\eta$. Moreover, a strong coupling of $N(1535)$ to $N{\eta }^{\prime }$ emerges (this is important for studies of ${\eta }^{\prime }$ production processes). Our approach shows that $N(1535)$ is predominantly the chiral partner of $N(939)$, and $\mathrm{\Lambda }(1670)$ the chiral partner of $\mathrm{\Lambda }(1116)$. Finally, our formalism can be used to couple the pseudoscalar glueball $\tilde{G}$ to baryons. We expect a large cross section for the reaction $\overline{p}p\to \tilde{G}\to \overline{p}p(1535)$, which can be experimentally tested in the future PANDA experiment.

Contrary to common perception, we show that the current Higgs data does not eliminate the possibility of a sequential fourth generation that get their masses through the same Higgs mechanism as the first three generations. The inability to fix the sign of the bottom-quark Yukawa coupling from the available data plays a crucial role in accommodating a chiral fourth generation which is consistent with the bounds on the Higgs signal strengths. We show that effects of such a fourth generation can remain completely hidden not only in the production of the Higgs boson through gluon fusion but also to its subsequent decay to $\gamma \gamma$ and $Z\gamma$. This, however, is feasible only if the scalar sector of the standard model is extended. We also provide a practical example illustrating how our general prescription can be embedded in a realistic model.