We describe the challenges and pathways when probing inflaton as dark matter with the stochastic gravitational waves (GWs) signal generated during the (p)reheating. Such scenarios are of utmost interest when no other interaction between the visible and dark sectors is present, therefore having no other detectability prospects. We consider the remnant energy in the coherently oscillating inflaton’s zeroth mode to contribute to the observed relic dark matter density in the Universe. To fully capture the nonlinear dynamics and the effects of backreactions during the oscillation, we resort to full nonlinear lattice simulation with pseudospectral methods to eliminate the differencing noises. We investigate for models whose behavior during the reheating era is of $m_{\mathrm{\Phi }}^2{\mathrm{\Phi }}^2$ type and find the typical primordial stochastic GWs backgrounds spectrum from scatterings among highly populated inflaton modes behaving like matter. We comment on the challenges of constructing viable inflationary models such that the inflaton will account for the total dark matter of the Universe while the produced GWs are within the future GWs detectors e.g., BBO, DECIGO, PTA, AION-MAGIS, and CE. We also describe the necessary modifications to the standard perturbative reheating scenario to prevent the depletion of residual inflaton energy via perturbative decay.

The core-collapse of massive stars and the merger of neutron star binaries are among the most promising candidate sites for the production of high-energy cosmic neutrinos. We demonstrate that the high-energy neutrinos produced in such extreme environments can experience efficient flavor conversions on scales much shorter than those expected in vacuum, due to their coherent forward scatterings with the bath of decohered low-energy neutrinos emitted from the central engine. These low-energy neutrinos, which exist as mass eigenstates, provide a very special and peculiar dominant background for the propagation of the high-energy ones. We point out that the high-energy neutrino flavor ratio is modified to a value independent of neutrinos energies, which is distinct from the conventional prediction with the matter effect. We also suggest that the signals can be used as a novel probe of new neutrino interactions beyond the Standard Model. This is yet another context where neutrino-neutrino interactions can play a crucial role in their flavor evolution.

The sensitivity of current and future neutrino detectors like Super-Kamiokande (SK), JUNO, Hyper-Kamiokande (HK), and DUNE is expected to allow for the detection of the diffuse supernova neutrino background (DSNB). However, the DSNB model ingredients like the core-collapse supernova (CCSN) rate, neutrino emission spectra, and the fraction of failed supernovae are not precisely known. We quantify the uncertainty on each of these ingredients by (i) compiling a large database of recent star formation rate density measurements, (ii) combining neutrino emission from long-term axisymmetric CCSNe simulations and strategies for estimating the emission from the protoneutron star cooling phase, and (iii) assuming different models of failed supernovae. Finally, we calculate the fluxes and event rates at multiple experiments and perform a simplified statistical estimate of the time required to significantly detect the DSNB at SK with the gadolinium upgrade and JUNO. Our fiducial model predicts a flux of $5.1\pm {0.4}_{-2.0-2.7}^{+0.0+0.5}{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$ at SK employing Gd-tagging, or $3.6\pm {0.3}_{-1.6-1.9}^{+0.0+0.8}$ events per year, where the errors represent our uncertainty from star formation rate density measurements, uncertainty in neutrino emission, and uncertainty in the failed supernova scenario. In this fiducial calculation, we could see a $3\sigma$ detection by $\sim 2030$ with SK-Gd and a $5\sigma$ detection by $\sim 2035$ with a joint SK-Gd/JUNO analysis, but background reduction remains crucial.

We present the early release of the atlas of continuous gravitational waves covering frequencies from 20 Hz to 1500 Hz and spindowns from $-5\times {10}^{-10}$ to $5\times {10}^{-10}\mathrm{Hz}/\mathrm{s}$. Compared to the previous atlas release we have greatly expanded the parameter space, and we now also provide polarization-specific data—both for signal-to-noise ratios and for the upper limits. Continuous wave searches are computationally difficult and take a long time to complete. The atlas enables new searches to be performed using modest computing power. To allow new searches to start sooner, we are releasing this data early, before our followup stages have completed.

In the present study, the calculations of two-body decays $B_s^0\to TT$ [$T$ denotes tensor mesons, $a_2(1320)$, $K_2^{*}(1430)$, $f_2(1270)$, $f_2^{\prime }(1525)$] in the perturbative QCD approach are presented. The ensuing predictions encompass branching ratios, polarization fractions, and direct $CP$ violations, all elucidated in comprehensive detail. It is discerned that (1) for pure annihilation decay, the longitudinal polarization is around 90.0%, whereas the transverse polarizations manifest comparatively diminutive magnitudes. (2) The direct $CP$ asymmetry is directly proportional to the interference between the tree and penguin contributions. For most of the decays investigated within this discourse, the direct $CP$ asymmetry remains modest in magnitude. (3) There are precisely six distinct categories of Feynman diagrams for $B_s^0\to TT$, because the tensor mesons cannot be produced through the ($V\pm A$) currents or ($S\pm P$) density, thereby prohibiting factorizable emission diagrams. The nonfactorizable and annihilation contributions are ascertained to be pivotal in these decay modes. The calculated branching ratios of our calculation for $B_s^0\to TT$ are at the order of ${10}^{-6}$ and ${10}^{-7}$, which can be tested in the LHCb and Belle II experiments. (4) Mixing exists for the $f_2(1270)$ and $f_2^{\prime }(1525)$, just as the $\eta$ and ${\eta }^{\prime }$ mixing, the branching ratios about the mixing angle $\theta$ are given in this work. However, it is different from $f_1(1285)-f_1(1420)$, the mixing angle is notably small, thereby resulting in only marginal alterations in the decay branching ratios.

$\gamma$-ray emission of blazars infer the presence of large-scale magnetic fields in the intergalactic medium, but their origin remains a mystery. Using recent data from MAGIC, H.E.S.S., and Fermi-LAT, we investigate whether the large-scale magnetic fields in the intergalactic medium could have been generated by a first-order electroweak phase transition in the two-Higgs-doublet model (2HDM). We study two representative scenarios where we vary the initial conditions of the magnetic field and the plasma, assuming either a primordial magnetic field with maximal magnetic helicity or a primordial magnetic field with negligible magnetic helicity in a plasma with kinetic helicity. By considering a primordial magnetic field with maximal helicity and applying the conservative constraints derived from MAGIC and Fermi-LAT data, we demonstrate that a first-order electroweak phase transition within the 2HDM may account for the observed intergalactic magnetic fields in the case of the strongest transitions. We show that this parameter space also predicts strong gravitational wave signals in the reach of space-based detectors such as LISA, providing a striking multimessenger signal of the 2HDM.

The presence of dark matter overdensities surrounding a black hole can influence the evolution of a binary system. The gravitational wave signals emitted by a black hole binary offer a promising means to probe the dark matter environments near a black hole. The dense region of dark matter can lead to the dephasing of gravitational waveforms, which can be detected by upcoming experiments such as the Laser Interferometer Space Antenna (LISA). The dark matter density profile around the black hole can vary for different dark matter models. Our study specifically investigates the impact of the ultralight self-interacting scalar dark matter (SIDM) on the gravitational wave signals emitted by black hole binaries. A distinctive characteristic of SIDM surrounding a black hole, as opposed to collisionless dark matter, is the formation of a soliton core. We perform a Fisher matrix analysis to estimate the size of the soliton and the corresponding SIDM parameter space that future LISA-like gravitational wave experiments can explore.

We investigate new physics with light-neutral mediators through coherent elastic neutrino-nucleus scattering ($\mathrm{CE}\nu \mathrm{NS}$) at low energies. These mediators, with a mass of less than 1 GeV, are common properties for extensions of the Standard Model (SM). We consider general scalar, vector, and tensor interactions allowed by Lorentz invariance and involve universal light mediators accordingly. In addition, we study an additional vector gauge boson with an associated $U(1{)}^{\prime }$ gauge group for a variety of models including $U(1{)}_{B-L}$, $U(1{)}_{B-3L_e}$, $U(1{)}_{B-3L_{\mu }}$, and $U(1{)}_{B-3L_{\tau }}$. These models differ in the fermion charges, which determine their contributions within the $\mathrm{CE}\nu \mathrm{NS}$ process. The effects of each model are investigated by embedding them in the SM process using solar neutrino flux. We derive new limits on the coupling-mass plane of these models from the latest CDEX-10 data. We also present projected sensitivities involving the future experimental developments for each model. Our results provide more stringent constraints in some regions, compared to previous works. Furthermore, the projected sensitivities yield an improvement of up to one order of magnitude.

The nuclear reaction network within the interior of the Sun is an efficient MeV physics factory and can produce long-lived particles generic to dark sector models. In this work we consider the sensitivity of satellite instruments, primarily the RHESSI spectrometer, that observe the quiet Sun in the MeV regime where backgrounds are low. We find that quiet Sun observations offer a powerful and complementary probe in regions of parameter space, where the long-lived particle decay length is longer than the radius of the Sun and shorter than the distance between the Sun and Earth. We comment on connections to recent model-building work on heavy neutral leptons coupled to neutrinos and high-quality axions from mirror symmetries.

The effective potential has been previously calculated through three-loop order, in Landau gauge, for a general renormalizable theory using dimensional regularization. However, dimensional regularization is not appropriate for softly broken supersymmetric gauge theories, because it explicitly violates supersymmetry. In this paper, I obtain the three-loop effective potential using a supersymmetric regulator based on dimensional reduction. Checks follow from the vanishing of the effective potential in examples with supersymmetric vacua, and from renormalization-scale invariance in examples for which supersymmetry is broken, either spontaneously or explicitly by soft terms. As by-products, I obtain the three-loop Landau gauge anomalous dimension for the scalar component of a chiral supermultiplet, and the beta function for the field-independent vacuum energy.

In this work, we explore the potential of probing the inelastic dark matter (DM) model with an extra $U(1{)}_D$ gauge symmetry at the Large Hadron Collider, Forward Search Experiment, and Super Tau Charm Factory. To saturate the observed DM relic density, the mass splitting between two light dark states has to be small enough and thus leads to some distinctive signatures at these colliders. By searching for the long-lived particle, the displaced muon jets, the soft leptons, and the monophoton events, we find that the inelastic DM mass in the range of 1 MeV to 210 GeV could be tested.

We compute the heavy quark momentum diffusion coefficient $\kappa$ using QCD kinetic theory for a system going through bottom-up isotropization in the initial stages of a heavy ion collision. We find that the values of $\kappa$ are within 30% from a thermal system at the same energy density. When matching for other quantities we observe considerably larger deviations. We also observe that the diffusion coefficient in the transverse direction is larger at high occupation numbers, whereas for an underoccupied system the longitudinal diffusion coefficient dominates. The behavior of the diffusion coefficient can be understood on a qualitative level based on the Debye mass $m_D$ and the effective temperature of soft modes $T_{*}$. Our findings for the kinetic evolution of $\kappa$ in different directions can be used in phenomenological descriptions of heavy quark diffusion and quarkonium dynamics to include the impact of preequilibrium stages.

We employ a model based on nucleonic and mesonic degrees of freedom to discuss the competition between isotropic and anisotropic phases in cold and dense matter. Assuming isotropy, the model exhibits a chiral phase transition which is of second order in the chiral limit and becomes a crossover in the case of a realistic pion mass. This observation crucially depends on the presence of the nucleonic vacuum contribution. Allowing for an anisotropic phase in the form of a chiral density wave can disrupt the smooth crossover. We identify the regions in the parameter space of the model where a chiral density wave is energetically preferred. A high-density reappearance of the chiral density wave with unphysical behavior, as seen in previous studies, is avoided by a suitable renormalization scheme. A nonzero pion mass tends to disfavor the anisotropic phase compared to the chiral limit and we find that, within our model, the chiral density wave is only realized for baryon densities of at least about 6 times nuclear saturation density.

The spectrum of the $cqq$ baryons contains a few states whose nature is not clearly a three-quark composite and which might have a sizable baryon-meson component. Examples include the ${\mathrm{\Sigma }}_c(2800)$ or the ${\mathrm{\Lambda }}_c(2940)$. Here we explore the spectrum of two-body systems composed of a light, octet baryon and a charmed meson (or antimeson) within a simple contact-range theory in which the couplings are saturated by light-meson exchanges. This results in the prediction of a series of composite anticharmed pentaquarks ($\overline{c}qqqq$) and singly charmed baryons ($c\overline{q}qqq$). Among the latter we find $J=\frac{1}{2}$ $\mathrm{\Xi }D$ and $J=\frac{3}{2}$ $\mathrm{\Xi }{D}^{*}$ bound states with masses matching those of the recently observed ${\mathrm{\Omega }}_c(3185)$ and ${\mathrm{\Omega }}_c(3327)$ baryons.

We analyze some aspects of the perturbative and nonperturbative interactions in the composition of heavy quarkonia, heavy and light baryons ($ccc$ and $uuu$ ones), as well as all charm tetraquarks ($cc\overline{c}\overline{c}$). Using the hyperspherical approximation and effective radial potentials (in six and nine dimensions, respectively) we derive their spectra and wave functions. In all of the cases, we focus on the splittings between the $S$-shell levels, which are remarkably insensitive to the quark masses, but proportional to the effective interaction potentials. We use the traditional Cornell-like potentials, and the nonperturbative instanton-induced static potentials, from correlators of two, three, and four Wilson lines, and find rather satisfactory description of spectra in all cases.

We argue that the celestial conformal field theory exhibits patterns of a logarithmic conformal field theory. We uncover a Jordan block structure involving the celestial stress tensor and its logarithmic partner, a composite operator built from the stress tensor and the Liouville field. Using a limiting process whose parameter corresponds to the infrared cutoff of gravity, we perform some basic consistency checks, particularly the calculation of two-point correlators, which reveals the expected logarithmic behavior. We comment on the vanishing value of the central charge in the celestial conformal field theory and explain how the logarithmic partner is relevant for its well-behavedness.

We investigate the quasinormal mode (QNM) spectra for scalar and electromagnetic fields over a covariant loop quantum gravity (LQG) black hole. For the fundamental modes, the LQG effect reduces the oscillations in the scalar field, however, it induces stronger oscillations in the electromagnetic field compared to the classical case. Under the scalar field perturbation, the system enjoys faster decaying modes with more oscillations than the electromagnetic field. Some peculiar phenomena emerge in the QNM spectra with higher overtones. A notable feature is the substantial divergence observed in the first several overtones from their Schwarzschild counterparts, with this discrepancy becoming magnified as the overtone number increases. Another remarkable phenomenon in higher overtones is that the quasinormal frequencies of the scalar field with $l=0$ exhibit an oscillatory behavior as the quantum parameter $r_0$ increases significantly. These oscillations intensify with the rising overtone number. We hypothesize that this oscillatory pattern may be associated with the extremal effect.

We explore the double copy for self-dual gauge and gravitational fields on self-dual background spacetimes. We consider backgrounds associated with solutions of the second Plebanski equation and describe results with different gauge-fixing conditions. Finally we discuss the kinematic and $w$-algebras and the double copy, identifying modified Poisson structures and kinematic structure constants in the presence of the self-dual background. The self-dual plane wave and Eguchi-Hanson spacetimes are studied as examples and their respective $w$-algebras derived.

We apply a novel background independent regularization scheme, the $N$-cutoffs, to self-consistently quantize scalar and metric fluctuations on the maximally symmetric but noncompact hyperbolic space. For quantum matter fields on a classical background or full quantum Einstein gravity (regarded here as an effective field theory) treated in the background field formalism, the $N$-cutoff is an ultraviolet regularization of the fields’ mode content that is independent of the background hyperbolic space metric. For each $N>0$, the regularized system backreacts on the geometry to dynamically determine the self-consistent background metric. The limit in which the regularization is removed then automatically yields the “physically correct” spacetime on which the resulting quantum field theory lives. When self-consistently quantized with the $N$-cutoff, we find that without any fine-tuning of parameters, the vacuum fluctuations of scalar and (linearized) graviton fields do not lead to the usual cosmological constant problem of a curvature singularity. Instead, the presence of increasingly many field modes tends to reduce the negative curvature of hyperbolic space, leading to vanishing values in the limit of removing the cutoff.

Since the derivation of a well-defined $D\to 4$ limit for 4D Einstein Gauss-Bonnet (4DEGB) gravity coupled to a scalar field, there has been interest in testing it as an alternative to Einstein’s general theory of relativity. Using the Tolman-Oppenheimer-Volkoff equations modified for 4DEGB gravity, we model the stellar structure of quark stars using a novel interacting quark matter equation of state. We find that increasing the Gauss-Bonnet coupling constant $\alpha$ or the interaction parameter $\lambda$ both tend to increase the mass-radius profiles of quark stars described by this theory, allowing a given central pressure to support larger quark stars in general. These results logically extend to cases where $\lambda <0$, in which increasing the magnitude of the interaction effects instead diminishes masses and radii. We also analytically identify a critical central pressure in both regimes, below which no quark star solutions exist due to the pressure function having no roots. Most interestingly, we find that quark stars can exist below the general relativistic Buchdahl bound and Schwarzschild radius $R=2M$, due to the lack of a mass gap between black holes and compact stars in the 4DEGB theory. Even for small $\alpha$ well within current observational constraints, we find that quark star solutions in this theory can describe extreme compact objects, objects whose radii are smaller than what is allowed by general relativity.