We develop a model for frequency-domain gravitational waveforms from inspiraling binary neutron stars. Our waveform model is calibrated by comparison with hybrid waveforms constructed from our latest high-precision numerical-relativity waveforms and the SEOBNRv2T waveforms in the frequency range of 10–1000 Hz. We show that the phase difference between our waveform model and the hybrid waveforms is always smaller than 0.1 rad for the binary tidal deformability $\tilde{\mathrm{\Lambda }}$ in the range $300\lesssim \tilde{\mathrm{\Lambda }}\lesssim 1900$ and for a mass ratio between 0.73 and 1. We show that, for 10–1000 Hz, the distinguishability for the signal-to-noise ratio $\lesssim 50$ and the mismatch between our waveform model and the hybrid waveforms are always smaller than 0.25 and $1.1\times {10}^{-5}$, respectively. The systematic error of our waveform model in the measurement of $\tilde{\mathrm{\Lambda }}$ is always smaller than 20 with respect to the hybrid waveforms for $300\lesssim \tilde{\mathrm{\Lambda }}\lesssim 1900$. The statistical error in the measurement of binary parameters is computed employing our waveform model, and we obtain results consistent with the previous studies. We show that the systematic error of our waveform model is always smaller than 20% (typically smaller than 10%) of the statistical error for events with a signal-to-noise ratio of 50.

Chameleon field is one of the promising candidates of dark energy scalar fields. As in all viable candidate field theories, a screening mechanism is implemented to be consistent with all existing tests of general relativity. The screening effect in the chameleon theory manifests its influence limited only to the thin outer layer of a bulk object, thus producing extra forces orders of magnitude weaker than that of the gravitational force of the bulk. For pointlike particles such as atoms, the depth of screening is larger than the size of the particle, such that the screening mechanism is ineffective and the chameleon force is fully expressed on the atomic test particles. Extra force measurements using atom interferometry are thus much more sensitive than bulk mass based measurements, and indeed have placed the most stringent constraints on the parameters characterizing chameleon field. In this paper, we present a conceptual measurement approach for chameleon force detection using atom interferometry in microgravity, in which multiloop atom interferometers exploit specially designed periodic modulation of chameleon fields. We show that major systematics of the dark energy force measurements, i.e., effects of gravitational forces and their gradients, can be suppressed below all hypothetical chameleon signals in the parameter space of interest.

Modes with wavelengths larger than the survey window can have significant impact on the covariance within the survey window. The supersample covariance has been recognized as an important source of covariance for the power spectrum on small scales, and it can potentially be important for the bispectrum covariance as well. In this paper, using the response function formalism, we model the supersample covariance contributions to the bispectrum covariance and the cross-covariance between the power spectrum and the bispectrum. The supersample covariances due to the long-wavelength density and tidal perturbations are investigated, and the tidal contribution is a few orders of magnitude smaller than the density one because in configuration space the bispectrum estimator involves angular averaging and the tidal response function is anisotropic. The impact of the super-survey modes is quantified using numerical measurements with periodic box and sub-box setups. For the matter bispectrum, the ratio between the supersample covariance correction and the small-scale covariance—which can be computed using a periodic box—is roughly an order of magnitude smaller than that for the matter power spectrum. This is because for the bispectrum, the small-scale non-Gaussian covariance is significantly larger than that for the power spectrum. For the cross-covariance, the supersample covariance is as important as for the power spectrum covariance. The supersample covariance prediction with the halo model response function is in good agreement with numerical results.

If the gamma-ray excess from the Galactic Center reported by Fermi-LAT is a signal from annihilating dark matter, one must question why a similar excess has not been observed in dwarf spheroidal galaxies. We use this observation to place constraints on the density profile of dwarf spheroidal galaxies under the assumption that the Galactic Center excess is in fact a signal from annihilating dark matter. We place constraints on the generalized Navarro-Frenk-White (NFW) parameter $\gamma$ and the Einasto profile parameter $\alpha$ which control the logarithmic slope of the inner regions of the halo’s density profile. The best-fit halo parameters $R_s$ and ${\rho }_s$ are determined using stellar kinematic data for a range of $\gamma$ and $\alpha$. We determine that under these assumptions the Galactic Center excess is inconsistent with the standard NFW profile (and other “cuspy” profiles) for dwarf spheroidal galaxies, but is consistent with observations of cored dwarf galaxy profiles. Specifically, we find that dwarf spheroidal profiles must be less cuspy than that of the Milky Way. Models of dark matter which self-interacts through a light mediator can achieve this.

The LIGO’s discovery of binary black hole mergers has opened up a new era of transient gravitational wave astronomy. The potential detection of gravitational radiation from another class of astronomical objects, rapidly spinning nonaxisymmetric neutron stars, would constitute a new area of gravitational wave astronomy. Scorpius X-1 (Sco X-1) is one of the most promising sources of continuous gravitational radiation to be detected with present-generation ground-based gravitational wave detectors, such as Advanced LIGO and Advanced Virgo. As the sensitivity of these detectors improve in the coming years, so will power of the search algorithms being used to find gravitational wave signals. Those searches will still require integration over nearly year long observational spans to detect the incredibly weak signals from rotating neutron stars. For low mass X-ray binaries such as Sco X-1 this difficult task is compounded by neutron star “spin wandering” caused by stochastic accretion fluctuations. In this paper, we analyze X-ray data from the $RXTE$ satellite to infer the fluctuating torque on the neutron star in Sco X-1. We then perform a large-scale simulation to quantify the statistical properties of spin-wandering effects on the gravitational wave signal frequency and phase evolution. We find that there are a broad range of expected maximum levels of frequency wandering corresponding to maximum drifts of between $0.3–50\mu \mathrm{Hz}/\sec$ over a year at 99% confidence. These results can be cast in terms of the maximum allowed length of a coherent signal model neglecting spin-wandering effects as ranging between 5–80 days. This study is designed to guide the development and evaluation of Sco X-1 search algorithms.

Ultracompact minihalos (UCMHs) have emerged as a valuable probe of the primordial power spectrum of density fluctuations at small scales. UCMHs are expected to form at early times in regions with $\delta \rho /\rho \gtrsim {10}^{-3}$, and they are theorized to possess an extremely compact $\rho \propto r^{-9/4}$ radial density profile, which enhances their observable signatures. Nonobservation of UCMHs can thus constrain the primordial power spectrum. Using $N$-body simulations to study the collapse of extreme density peaks at $z\simeq 1000$, we show that UCMHs forming under realistic conditions do not develop the $\rho \propto r^{-9/4}$ profile and instead develop either $\rho \propto r^{-3/2}$ or $\rho \propto r^{-1}$ inner density profiles depending on the shape of the power spectrum. We also demonstrate via idealized simulations that self-similarity—the absence of a scale length—is necessary to produce a halo with the $\rho \propto r^{-9/4}$ profile, and we argue that this implies such halos cannot form from a Gaussian primordial density field. Prior constraints derived from UCMH nonobservation must be reworked in light of this discovery. Although the shallower density profile reduces UCMH visibility, our findings reduce their signal by as little as $\mathcal{O}({10}^{-2})$ while allowing later-forming halos to be considered, which suggests that new constraints could be significantly stronger.

The Dirac-Heisenberg-Wigner formalism is employed to investigate electron-positron pair production in cylindrically symmetric but otherwise spatially inhomogeneous, oscillating electric fields. The oscillation frequencies are hereby tuned to obtain multiphoton pair production in the nonperturbative threshold regime. An effective mass, as well as a trajectory-based semiclassical analysis, is introduced in order to interpret the numerical results for the distribution functions as well as for the particle yields and spectra. The results, including the asymptotic particle spectra, display clear signatures of ponderomotive forces.

We show that gauge coupling unification in supersymmetry (SUSY) models can make a nontrivial interconnection between collider and proton decay experiments. Under the assumption of precise gauge coupling unification in the Minimal Supersymmeric Standard Model, with negligible grand unified theories threshold corrections, the low energy SUSY spectrum and the unification scale are intertwined, and the lower bound on the proton lifetime can be translated into upper bounds on SUSY masses. We find that the current limit on $\tau (P\to {\pi }^0{e}^{+})$ already excludes gluinos heavier than $\sim 70$ (120 and 200) TeV if their mass ratio to winos, $R\equiv M_3/M_2$, is $\sim 1$ (3 and 7), respectively. Next generation nucleon decay experiments are expected to bring these upper bounds down to $\sim 5$ (10 and 15) TeV for $R\sim 1$ (3 and 7).

We consider a neutrinophilic Higgs scenario where the Standard Model is extended by one additional Higgs doublet and three generations of singlet right-handed Majorana neutrinos. Light neutrino masses are generated through mixing with the heavy neutrinos via the Type-I seesaw mechanism when the neutrinophilic Higgs gets a vacuum expectation value (VEV). The Dirac neutrino Yukawa coupling in this scenario can be sizable compared to those in the canonical Type-I seesaw mechanism owing to the small neutrinophilic Higgs VEV giving rise to interesting phenomenological consequences. We have explored various signal regions likely to provide a hint of such a scenario at the LHC as well as at future $e^{+}{e}^{-}$ colliders. We have also highlighted the consequences of light neutrino mass hierarchies in collider phenomenology that can complement the findings of neutrino oscillation experiments.

The measured value of the Higgs quartic coupling $\lambda$ is peculiarly close to the critical value above which the Higgs potential becomes unstable, when extrapolated to high scales by renormalization group running. It is tempting to speculate that there is an anthropic reason behind this near-criticality. We show how an axionic field can provide a landscape of vacuum states in which $\lambda$ scans. These states are populated during inflation to create a multiverse with different quartic couplings, with a probability distribution $P$ that can be computed. If $P$ is peaked in the anthropically forbidden region of Higgs instability, then the most probable universe compatible with observers would be close to the boundary, as observed. We discuss three scenarios depending on the Higgs vacuum selection mechanism: decay by quantum tunneling, by thermal fluctuations, or by inflationary fluctuations.

The conformal standard model is a minimal extension of the Standard Model (SM) of particle physics based on the assumed absence of large intermediate scales between the TeV scale and the Planck scale, which incorporates only right-chiral neutrinos and a new complex scalar in addition to the usual SM degrees of freedom, but no other features such as supersymmetric partners. In this paper, we present a comprehensive quantitative analysis of this model, and show that all outstanding issues of particle physics proper can in principle be solved “in one go” within this framework. This includes in particular the stabilization of the electroweak scale, “minimal” leptogenesis and the explanation of dark matter, with a small mass and very weakly interacting Majoron as the dark matter candidate (for which we propose to use the name “minoron”). The main testable prediction of the model is a new and almost sterile scalar boson that would manifest itself as a narrow resonance in the TeV region. We give a representative range of parameter values consistent with our assumptions and with observation.

The recent data indicate that the neutrino mixing angle ${\theta }_{23}$ deviates from the maximal-mixing value of 45°, showing two nearly degenerate solutions, one in the lower octant (LO) (${\theta }_{23}<45°$) and one in the higher octant (HO) (${\theta }_{23}>45°$). We investigate, using numerical simulations, the prospects for determining the octant of ${\theta }_{23}$ in the future long baseline oscillation experiments. We present our results as contour plots on the (${\theta }_{23}-45°$, $\delta$)–plane, where $\delta$ is the $CP$ phase, showing the true values of ${\theta }_{23}$ for which the octant can be experimentally determined at $3\sigma$, $2\sigma$ and $1\sigma$ confidence level. In particular, we study the impact of the possible nonunitarity of neutrino mixing on the experimental determination of ${\theta }_{23}$ in those experiments.

We study the possibility to observe sterile neutrinos with masses in the range $5\mathrm{GeV}<m_N<20\mathrm{GeV}$ at the LHC, using the exclusive semileptonic modes involving pions, namely $W\to \ell N\to n\pi \ell \ell$ ($n=1,2,3$). The two pion and three pion modes require extrapolations of form factors to large time-like $q^2$, which we do using vector dominance models as well as light front holographic QCD, with remarkable agreement. This mass region is difficult to explore with inclusive $\ell \ell jj$ modes or trilepton modes and impossible to explore in rare meson decays. While particle identification is a real challenge in these modes, vertex displacement due to the long living neutrino in the above mass range can greatly help reduce backgrounds. Assuming a sample of $10^{9}W$ bosons at the end of the LHC Run 2, these modes could discover a sterile neutrino in the above mass range or improve the current bounds on the heavy-to-light lepton mixings by an order of magnitude, $|U_{\ell N}{|}^2\sim 2\times {10}^{-6}$. Moreover, by studying the equal sign and opposite sign dileptons, the Majorana or Dirac character of the sterile neutrino may be revealed.

We study the signatures of the triplet-quadruplet dark matter model at the LHC and future colliders, including the 100 TeV Super Proton-Proton Collider and the 240 GeV Circular Electron Positron Collider. The dark sector in this model contains one fermionic electroweak triplet and two fermionic quadruplets, which have two kinds of Yukawa couplings to the Higgs doublet. Electroweak production signals of the dark sector fermions in the $\text{monojet}+{\cancel{E}}_{\mathrm{T}}$, disappearing track, and $\text{multilepton}+{\cancel{E}}_{\mathrm{T}}$ channels at the LHC and the Super Proton-Proton Collider are investigated. Moreover, we study the loop effects of this model on the Circular Electron Positron Collider precision measurements of $e^{+}{e}^{-}\to Zh$ and $h\to \gamma \gamma$. We find that most of the parameter regions allowed by the observed dark matter relic density will be well explored by such direct and indirect searches at future colliders.

In this paper, we discuss and calculate the electroweak parameters $R_l$, $A_l$, and $N_{\nu }^l$ in a model that combines an inverse seesaw with the scotogenic model. Dark matter relic density is also considered. Because of the stringent constraint from the ATLAS experimental data, it is difficult to detect the loop effect on $R_l$, $A_l$ in this model considering both the theoretical and the future experimental uncertainties. However, $N_{\nu }^l$ can sometimes become large enough for the future experiments to verify.

We estimate contributions from Kaluza-Klein excitations of gauge bosons and physical charge scalar for the explanation of the lepton flavor universality violating excess in the ratios $\mathcal{R}(D)$ and $\mathcal{R}(D^{*})$ in 5 dimensional universal extra dimensional scenario with nonvanishing boundary localized terms. This model is conventionally known as nonminimal universal extra dimensional model. We obtain the allowed parameter space in accordance with constraints coming from $B_c\to \tau \nu$ decay, as well as those from the electroweak precision tests.

MuOn-decay MEdium baseline NeuTrino beam experiment (MOMENT) is a next-generation accelerator neutrino experiment, which can be used to probe new physics beyond the Standard Model. We try to simulate neutrino oscillations confronting charged-current and nonstandard neutrino interactions (CC-NSIs) at MOMENT. These NSIs could alter neutrino production and detection processes and interfere with neutrino oscillation channels. We separate a perturbative discussion of oscillation channels at near and far detectors, and analyze parameter correlations with the impact of CC-NSIs. Taking ${\delta }_{cp}$ and ${\theta }_{23}$ as an example, we find that CC-NSIs can induce bias in precision measurements of standard oscillation parameters. In addition, a combination of near and far detectors using Gd-doped water Cherenkov technology at MOMENT is able to provide good constraints of CC-NSIs happening to the neutrino production and detection processes.

We calculate in three-flavor lattice QCD the short-distance hadronic matrix elements of all five $\mathrm{\Delta }C=2$ four-fermion operators that contribute to neutral $D$-meson mixing both in and beyond the Standard Model. We use the MILC Collaboration’s $N_f=2+1$ lattice gauge-field configurations generated with asqtad-improved staggered sea quarks. We also employ the asqtad action for the valence light quarks and use the clover action with the Fermilab interpretation for the charm quark. We analyze a large set of ensembles with pions as light as $M_{\pi }\approx 180\mathrm{MeV}$ and lattice spacings as fine as $a\approx 0.045\mathrm{fm}$, thereby enabling good control over the extrapolation to the physical pion mass and continuum limit. We obtain for the matrix elements in the $\overline{\mathrm{MS}}\text{−}\mathrm{NDR}$ scheme using the choice of evanescent operators proposed by Beneke et al., evaluated at 3 GeV, $⟨D^0|{\mathcal{O}}_i|{\overline{D}}^0⟩=\{0.0805(55)(16),-0.1561(70)(31),0.0464(31)(9),0.2747(129)(55),0.1035(71)(21)\}{\mathrm{GeV}}^4$ ($i=1–5$). The errors shown are from statistics and lattice systematics, and the omission of charmed sea quarks, respectively. To illustrate the utility of our matrix-element results, we place bounds on the scale of $CP$-violating new physics in $D^0$ mixing, finding lower limits of about $10–50\times {10}^3\mathrm{TeV}$ for couplings of $\mathrm{O}(1)$. To enable our results to be employed in more sophisticated or model-specific phenomenological studies, we provide the correlations among our matrix-element results. For convenience, we also present numerical results in the other commonly used scheme of Buras, Misiak, and Urban.

Anisotropic lattice spacings are mandatory to reach the high temperatures where chiral symmetry is restored in the strong-coupling limit of lattice QCD. Here, we propose a simple criterion for the nonperturbative renormalization of the anisotropy coupling in strongly coupled $\mathrm{SU}(N_{\mathrm{c}})$ or $\mathrm{U}(N_{\mathrm{c}})$ lattice QCD with massless staggered fermions. We then compute the renormalized anisotropy, and the strong-coupling analogue of Karsch’s coefficients (the running anisotropy), for $N_{\mathrm{c}}=3$. We achieve high precision by combining diagrammatic Monte Carlo and multihistogram reweighting techniques. We observe that the mean field prediction in the continuous time limit captures the nonperturbative scaling, but receives a large, previously neglected correction on the unit prefactor. Using our nonperturbative prescription in place of the mean field result, we observe large corrections of the same magnitude to the continuous time limit of the static baryon mass and of the location of the phase boundary associated with chiral symmetry restoration. In particular, the phase boundary, evaluated on different finite lattices, has a dramatically smaller dependence on the lattice time extent. We also estimate, as a byproduct, the pion decay constant and the chiral condensate of massless SU(3) QCD in the strong-coupling limit at zero temperature.

The structure of the nucleon and the first radial excitation of the nucleon, the Roper, $N(1440)$, is studied within the formalism of light-front holography. The nucleon elastic form factors and ${\gamma }^{*}N\to N(1440)$ transition form factors are calculated under the assumption of the dominance of the valence quark degrees of freedom. Contrary to the previous studies, the bare parameters of the model associated with the valence quark are fixed by the empirical data for large momentum transfer ($Q^2$) assuming that the corrections to the three-quark picture (meson cloud contributions) are suppressed. The ${\gamma }^{*}N\to N(1440)$ transition form factors are then calculated without any adjustable parameters. Our estimates are compared with results from models based on valence quarks and others. The model compares well with the ${\gamma }^{*}N\to N(1440)$ transition form factor data, suggesting that meson cloud effects are not large, except in the region $Q^2<1.5{\mathrm{GeV}}^2$. In particular, the meson cloud contributions for the Pauli form factor are small.