The small-scale cosmic microwave background is dominated by anisotropies from the kinematic Sunyaev-Zeldovich (kSZ) effect, and upcoming experiments will measure it very precisely, but the optical depth degeneracy limits the cosmological information that can be extracted. At the same time, fast radio bursts (FRBs) are an exciting new frontier for astrophysics, but their usefulness as cosmological probes is currently unclear. We show that FRBs are uniquely suited for breaking the kSZ optical depth degeneracy. This opens up new possibilities for constraining cosmology with the kSZ effect, and new cosmological applications for FRBs.

Invisible neutrino decay modes are difficult to target at laboratory experiments, and current bounds on such decays from solar neutrino and neutrino oscillation experiments are somewhat weak. It has been known for some time that cosmology can serve as a powerful probe of invisible neutrino decays. In this work, we show that in order for big bang nucleosynthesis to be successful, the invisible neutrino decay lifetime is bounded to be ${\tau }_{\nu }>{10}^{-3}\mathrm{s}$ at 95% CL. We revisit cosmic microwave background constraints on invisible neutrino decays, and by using Planck2018 observations we find the following bound on the neutrino lifetime: ${\tau }_{\nu }>(1.3–0.3)\times {10}^9\mathrm{s}{(m_{\nu }/0.05\mathrm{eV})}^3$ at 95% CL. We show that this bound is robust to modifications of the cosmological model, in particular that it is independent of the presence of dark radiation. We find that lifetimes relevant for Supernova observations (${\tau }_{\nu }\sim {10}^5\mathrm{s}{(m_{\nu }/0.05\mathrm{eV})}^3$) are disfavored at more than $5\sigma$ with respect to $\mathrm{\Lambda }\mathrm{CDM}$ given the latest Planck CMB observations. Finally, we show that when including high-$\ell$ Planck polarization data, neutrino lifetimes ${\tau }_{\nu }=(2–16)\times {10}^9\mathrm{s}{(m_{\nu }/0.05\mathrm{eV})}^3$ are mildly preferred—with a $1\text{−}2\sigma$ significance—over neutrinos being stable.

Compensated isocurvature perturbations (CIPs) are modulations of the relative baryon and dark matter density that leave the total matter density constant. The best current constraints from the primary cosmic microwave background (CMB) are consistent with CIPs some 2 orders of magnitude larger in amplitude than adiabatic perturbations, suggesting that there may be a huge gap in our knowledge of the early Universe. However, it was recently suggested by Barreira et al. that CIPs that are correlated with the primordial curvature perturbation, as arises in some versions of the curvaton model, lead to a new observable: scale-dependent galaxy bias. Combining a galaxy survey with an unbiased tracer of the density field facilitates a measurement of the amplitude of correlated CIPs that is free from cosmic variance, the main limitation on constraints from the primary CMB. Among the most promising tracers to use for this purpose is the remote dipole field, reconstructed using the technique of kinetic Sunyaev Zel’dovich (kSZ) tomography. In this paper, we evaluate the detection significance on the amplitude of correlated CIPs possible with next-generation CMB and galaxy surveys using kSZ tomography. Our analysis includes all relativistic contributions to the observed galaxy number counts and allows for both CIPs and primordial non-Gaussianity, which also gives rise to a scale-dependent galaxy bias. We find that kSZ tomography can probe CIPs of comparable amplitude to the adiabatic fluctuations, representing an improvement of over 2 orders of magnitude upon current constraints, and an order of magnitude over what will be possible using future CMB or galaxy surveys alone.

We develop a field-theoretic description of large-scale structure formation by taking the nonrelativistic limit of a canonically transformed, real scalar field which is minimally coupled to scalar gravitational perturbations in longitudinal gauge. We integrate out the gravitational constraint fields and arrive at a nonlocal action which is only specified in terms of the dynamical degrees of freedom. In order to make this framework closer to the classical particle description, we construct the corresponding 2PI effective action truncated at two loop order for a nonsqueezed state without field expectation values. We contrast the dynamical description of the coincident time phase-space density to the standard Vlasov description of cold dark matter particles and identify momentum and timescales at which linear perturbation theory will deviate from the standard evolution.

Neutron star interiors provide the opportunity to probe properties of cold dense matter in the QCD phase diagram. Utilizing models of dense matter in accord with nuclear systematics at nuclear densities, we investigate the compatibility of deconfined quark cores with current observational constraints on the maximum mass and tidal deformability of neutron stars. We explore various methods of implementing the hadron-to-quark phase transition, specifically, first-order transitions with sharp (Maxwell construction) and soft (Gibbs construction) interfaces, and smooth crossover transitions. We find that within the models we apply, hadronic matter has to be stiff for a first-order phase transition and soft for a crossover transition. In both scenarios and for the equations of state we employed, quarks appear at the center of premerger neutron stars in the mass range $\approx 1.0–1.6{\mathrm{M}}_{\odot }$, with a squared speed of sound $c_{\mathrm{QM}}^2\gtrsim 0.4$ characteristic of strong repulsive interactions required to support the recently discovered neutron star masses $\ge 2{\mathrm{M}}_{\odot }$. We also identify equations of state and phase transition scenarios that are consistent with the bounds placed on tidal deformations of neutron stars in the recent binary merger event GW170817. We emphasize that distinguishing hybrid stars with quark cores from normal hadronic stars is very difficult from the knowledge of masses and radii alone, unless drastic sharp transitions induce distinctive disconnected hybrid branches in the mass-radius relation.

We investigate the significance of a dark matter (DM) signal from the AMS-02 cosmic antiproton flux. Global fits to the data are performed under different propagation and hadronic interaction models. The uncertainties from the injection spectrum, propagation effects, and solar modulation of the cosmic rays are taken into account comprehensively. Since we need to investigate extended parameter regions with multiple free parameters in the fit, the machine learning method is adopted to maintain a realistic time cost. We find that a DM signal with DM mass $\sim 100\mathrm{GeV}$ or above 1 TeV would possibly be required. A comprehensive discussion is performed to clarify how are these uncertainties affecting the two kinds of DM signals. The low-energy DM signal is significant for the case with diffusive reacceleration propagation model $+$ charge-independent solar modulation configuration. However, it is severely affected by the propagation and solar modulation effects. On the other hand, the high-energy DM signal is mainly influenced by the hadronic interaction model. Most of the hadronic interaction models do not indicate a significant high-energy DM signal except that the EPOS-LHC interaction model always requires a high-energy DM signal with a significance more than $5\sigma$.

The CRESST experiment is a direct dark matter search which aims to measure interactions of potential dark matter particles in an Earth-bound detector. With the current stage, CRESST-III, we focus on a low energy threshold for increased sensitivity towards light dark matter particles. In this paper we describe the analysis of one detector operated in the first run of CRESST-III (05/2016–02/2018) achieving a nuclear recoil threshold of 30.1 eV. This result was obtained with a 23.6 g ${\mathrm{CaWO}}_4$ crystal operated as a cryogenic scintillating calorimeter in the CRESST setup at the Laboratori Nazionali del Gran Sasso (LNGS). Both the primary phonon (heat) signal and the simultaneously emitted scintillation light, which is absorbed in a separate silicon-on-sapphire light absorber, are measured with highly sensitive transition edge sensors operated at $\sim 15\mathrm{mK}$. The unique combination of these sensors with the light element oxygen present in our target yields sensitivity to dark matter particle masses as low as $160\mathrm{MeV}/{\mathrm{c}}^2$.

We study the dynamics of a classical scalar field that rolls down a linear potential as it interacts bi-quadratically with a quantum field. We explicitly solve the dynamical problem by using the classical-quantum correspondence (CQC). Rolling solutions on the effective potential are shown to compare very poorly with the full solution. Spatially homogeneous initial conditions maintain their homogeneity and small inhomogeneities in the initial conditions do not grow.

A full renormalization of the inert doublet model is presented and exploited for a precise calculation of the relic density of dark matter (DM) at one-loop. In this first paper, we study the case of a DM candidate with $m_{\mathrm{DM}}\sim 500\mathrm{GeV}$. In this regime, the coannihilation channels are important. We therefore compute, for a wide range of relative velocities, the full next-to-leading order electroweak corrections to seven annihilation/coannihilation processes that contribute $\sim 70\%$ to the relic density of DM. These corrected cross sections are interfaced with micromegas to obtain the one-loop correction to the freeze-out relic density. Due to the accurate measurement of this observable, the one-loop corrections are relevant. We discuss the one-loop renormalization scheme dependence and point out the influence, at one-loop, of a parameter that solely describes the scattering in the dark sector. A tree-level computation of the relic density is not sensitive to this parameter.

We calculate the bag parameters for neutral $B$-meson mixing in and beyond the Standard Model, in full four-flavor lattice QCD for the first time. We work on gluon field configurations that include the effect of $u$, $d$, $s$, and $c$ sea quarks with the highly improved staggered quark (HISQ) action at three values of the lattice spacing and with three $u/d$ quark masses going down to the physical value. The valence $b$ quarks use the improved nonrelativistic QCD action and the valence light quarks, the HISQ action. Our analysis was blinded. Our results for the bag parameters for all five operators are the most accurate to date. For the Standard Model operator between $B_s$ and $B_d$ mesons we find ${\widehat{B}}_{B_s}=1.232(53)$ and ${\widehat{B}}_{B_d}=1.222(61)$. Combining our results with lattice QCD calculations of the decay constants using HISQ quarks from the Fermilab/MILC Collaboration and with experimental values for $B_s$ and $B_d$ oscillation frequencies allows determination of the Cabibbo-Kobayashi-Maskawa (CKM) elements $V_{ts}$ and $V_{td}$. We find $|V_{ts}|=0.04189(93)$, $|V_{td}|=0.00867(23)$, and $|V_{ts}|/|V_{td}|=0.2071(27)$. Our results agree well (within $2\sigma$) with values determined from CKM unitarity constraints based on tree-level processes (only). Using a ratio to $\mathrm{\Delta }{M}_{s,d}$ in which CKM elements cancel in the Standard Model, we determine the branching fractions $\mathrm{Br}(B_s\to {\mu }^{+}{\mu }^{-})=3.81(18)\times {10}^{-9}$ and $\mathrm{Br}(B_d\to {\mu }^{+}{\mu }^{-})=1.031(54)\times {10}^{-10}$. We also give results for matrix elements of the operators $R_0$, $R_1$, and ${\tilde{R}}_1$ that contribute to neutral $B$-meson width differences.

A promising technology concept for sub-GeV dark matter detection is described, in which low-temperature microcalorimeters serve as the sensors and superfluid ${}^4\mathrm{He}$ serves as the target material. We name this concept “HeRALD,” helium roton apparatus for light dark matter. A superfluid helium target has several advantageous properties, including a light nuclear mass for better kinematic matching with light dark matter particles, copious production of scintillation light, extreme intrinsic radiopurity, high impedance to external vibration noise, and a unique “quantum evaporation” signal channel enabling the detection of phononlike modes via liberation of ${}^4\mathrm{He}$ atoms into a vacuum. In this concept, both scintillation photons and triplet excimers are detected using calorimeters, including calorimeters immersed in the superfluid. Kinetic excitations of the superfluid medium (rotons and phonons) are detected using quantum evaporation and subsequent atomic adsorption onto a calorimeter suspended in vacuum above the target helium. The energy of adsorption amplifies the phonon/roton signal before calorimetric sensing, producing a gain mechanism that can reduce the technology’s recoil energy threshold below the calorimeter energy threshold. We describe signal production and signal sensing probabilities, and estimate the resulting electron recoil discrimination. We simulate radioactive backgrounds from gamma rays and construct an overall background spectrum expectation also including neutrons and solar neutrinos. Finally, we calculate projected sensitivities to dark matter–nucleon elastic scattering, demonstrating that even very small (sub-kg) target masses can probe wide regions of as-yet untested dark matter parameter space.

We introduce a new approach to understand magnetization dynamics in ferromagnets based on the holographic realization of ferromagnets. A Landau-Lifshitz equation describing the magnetization dynamics is derived from a Yang-Mills equation in the dual gravitational theory, and temperature dependences of the spin-wave stiffness and spin transfer torque appearing in the holographic Landau-Lifshitz equation are investigated by the holographic approach. The results are consistent with the known properties of magnetization dynamics in ferromagnets with conduction electrons.

If active neutrinos undergo nonstandard (“secret”) interactions ($\mathrm{NS}\nu \mathrm{Is}$), the cosmological evolution of the neutrino fluid might be altered, leaving an imprint in cosmological observables. We use the latest publicly available CMB data from Planck to constrain $\mathrm{NS}\nu \mathrm{Is}$ inducing $\nu \text{−}\nu$ scattering, under the assumption that the mediator $\varphi$ of the secret interaction is very light. We find that the effective coupling constant of the interaction, $g_{\mathrm{eff}}^4\equiv ⟨\sigma v⟩T_{\nu }^2$, is constrained at $<2.35\times {10}^{-27}$ (95% Credible Interval), which strengthens to $g_{\mathrm{eff}}^4<1.64\times {10}^{-27}$ when Planck nonbaseline small-scale polarization is considered. Our findings imply that after decoupling at $T\simeq 1\mathrm{MeV}$, cosmic neutrinos are free-streaming at redshifts $z>3800$, or $z>2300$ if small-scale polarization is included. These bounds are only marginally improved when data from geometrical expansion probes are included in the analysis to complement Planck. We also find that the tensions between CMB and low-redshift measurements of the expansion rate $H_0$ and the amplitude of matter fluctuations ${\sigma }_8$ are not significantly reduced. Our results are independent of the underlying particle physics model as long as $\varphi$ is very light. Considering a model with Majorana neutrinos and a pseudoscalar mediator, we find that the coupling constant $g$ of the secret interaction is constrained at $\lesssim 7\times {10}^{-7}$. By further assuming that the pseudoscalar interaction comes from a dynamical realization of the seesaw mechanism, as in Majoron models, we can bound the scale of lepton number breaking $v_{\sigma }$ as $\gtrsim (1.4\times {10}^6)m_{\nu }$.

We study bulk viscosity arising from weak current Urca processes in dense baryonic matter at and beyond nuclear saturation density. We consider the temperature regime where neutrinos are trapped and therefore have nonzero chemical potential. We model the nuclear matter in a relativistic density functional approach, taking into account the trapped neutrino component. We find that the resonant maximum of the bulk viscosity would occur at or below the neutrino trapping temperature, so in the neutrino trapped regime the bulk viscosity decreases with temperature as $T^{-2}$, this decrease being interrupted by a drop to zero at a special temperature where the proton fraction becomes density-independent and the material scale-invariant. The bulk viscosity is larger for matter with lower lepton fraction, i.e., larger isospin asymmetry. We find that bulk viscosity in the neutrino-trapped regime is smaller by several orders of magnitude than in the neutrino-transparent regime, which implies that bulk viscosity in neutrino-trapped matter is probably not strong enough to affect significantly the evolution of neutron star mergers. This also implies weak damping of gravitational waves emitted by the oscillations of the post-merger remnant in the high-temperature, neutrino-trapped phase of evolution.

We consider the possibility that the Peccei-Quinn charged dynamical supersymmetry breaking (DSB) mechanism readily accommodates gauge mediation without the gravitino problem. Given a gravitino of $m_{3/2}=\mathcal{O}(\mathrm{eV})$ for the Intriligator-Seiberg-Shih model, an axion, converted from a Nambu-Goldstone boson, could become a dark matter candidate, while the QCD anomaly and a sizable $\mu$ value are naturally generated. We also stress that rather minimal DSB content is sufficient to yield the observed mass of the lightest Higgs boson, other than the acceptable soft mass of sparticles in the observable sector.

We present results for the Higgsstrahlung process within the geneva Monte Carlo framework. We combine the fully differential next-to-next-to-leading order (NNLO) calculation with the higher-order resummation in the 0-jettiness resolution variable (beam thrust). The resulting parton-level events are further showered and hadronized by pythia8. The beam thrust resummation is carried out to next-to-next-to-leading logarithmic accuracy, consistently incorporating all singular virtual and real NNLO corrections. It thus provides a natural perturbative connection between the NNLO calculation and the parton shower regime, including a systematic assessment of perturbative uncertainties. In this way, observables which are inclusive over the additional radiation are correct to NNLO, while the description of 0-jet -like resummation variables is improved beyond the parton shower approximation. We provide predictions for the 13 TeV LHC.

We present new sets of nuclear parton distribution functions (nPDFs) at next-to-leading order and next-to-next-to-leading order. Our analyses are based on deeply inelastic scattering data with charged-lepton and neutrino beams on nuclear targets. In addition, a set of proton baseline PDFs is fitted within the same framework with the same theoretical assumptions. The results of this global QCD analysis are compared to existing nPDF sets and to the fitted cross sections. Also, the uncertainties resulting from the limited constraining power of the included experimental data are presented. The published work is based on an open-source tool, xfitter, which has been modified to be applicable also for a nuclear PDF analysis. The required extensions of the code are discussed as well.

Using lattice simulations, we show that there is a phase of thermal QCD, where the spectral density $\rho (\lambda )$ of the Dirac operator changes as $1/\lambda$ for infrared eigenvalues $\lambda <T$. This behavior persists over the entire low energy band we can resolve accurately, over 3 orders of magnitude on our largest volumes. We propose that in this “IR phase,” the well-known noninteracting scale invariance at very short distances (UV, $\lambda \to \infty$, asymptotic freedom), coexists with a very different interacting type of scale invariance at long distances (IR, $\lambda <T$). Such dynamics may be responsible for the unusual fluidity properties of the medium observed at RHIC and LHC. We point out its connection to the physics of the Banks-Zaks fixed point, leading to the possibility of massless glueballs in the fluid. Our results lead to the classification of thermal QCD phases in terms of IR scale invariance. The ensuing picture naturally subsumes the standard chiral crossover feature at $“T_c”\approx 155\mathrm{MeV}$. Its crucial new aspect is the existence of temperature $T_{\mathrm{IR}}$ ($200\mathrm{MeV}<T_{\mathrm{IR}}<250\mathrm{MeV}$) marking the onset of the IR phase and possibly a true phase transition.

The LHCb collaboration has recently discovered three pentaquark-like states—the $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$—close to the $\overline{D}{\mathrm{\Sigma }}_c$ and the ${\overline{D}}^{*}{\mathrm{\Sigma }}_c$ meson-baryon thresholds. The standard interpretation is that they are heavy antimeson-baryon molecules. Their quantum numbers have not been determined yet, which implies two possibilities for the $P_c(4440)$ and $P_c(4457)$: $J^P={\frac{1}{2}}^{-}$ and $J^P={\frac{3}{2}}^{-}$. The preferred interpretation within a contact-range effective field theory is that the $P_c(4440)$ is the $J^P={\frac{1}{2}}^{-}$ molecule, while the $P_c(4457)$ is the $J^P={\frac{3}{2}}^{-}$ one. Here we show that when the one pion exchange potential between the heavy antimeson and heavy baryon is taken into account, this conclusion changes, with the contrary identification being as likely as the original one. The identification is however cutoff dependent, which suggests that improvements of the present description (e.g., the inclusion of subleading order corrections, like two-pion exchanges) are necessary in order to disambiguate the spectroscopy of the molecular pentaquarks.

We find a novel mechanism for generating transverse single-spin asymmetry (SSA) in semi-inclusive deep inelastic scattering, distinct from the known ones which involve the Sivers and Collins functions, or their collinear twist-three counterparts. It is demonstrated that a phase needed for SSA can be produced purely within a parton-level cross section starting at two loops. We identify the complete set of two-loop diagrams for SSA, and discuss their gauge invariance and collinear factorization which features the $g_T$ distribution function. In the $k_T$ factorization framework, many more sources for SSA exist, and contributions from all possible two-parton transverse-momentum-dependent parton distribution functions are presented up to two loops and twist three.