Direct searches for new particles at colliders have traditionally been factorized into model proposals by theorists and model testing by experimentalists. With the recent advent of machine learning methods that allow for the simultaneous unfolding of all observables in a given phase space region, there is a new opportunity to blur these traditional boundaries by performing searches on unfolded data. This could facilitate a research program where data are explored in their natural high dimensionality with as little model bias as possible. We study how the information about physics beyond the Standard Model is preserved by full phase space unfolding using an important physics target at the Large Hadron Collider (LHC); exotic Higgs boson decays involving hadronic final states. We find that if the signal cross section is high enough, information about the new physics is visible in the unfolded data. We will show that in some cases, quantifiably all of the high-level information about the new physics is encoded in the unfolded data. Finally, we show that there are still many cases when the unfolding does not work fully or precisely, such as when the signal cross section is small. This study will serve as an important benchmark for enhancing unfolding methods for the LHC and beyond.

Search strategies for the third-generation leptoquarks (LQs) are distinct from other LQ searches, especially when they decay to a top quark and a $\tau$ lepton. We investigate the cases of all TeV-scale scalar and vector LQs that decay to either a top-tau pair (charge-$1/3$ and charge- $5/3$ LQs) or a top-neutrino pair (charge-$2/3$ LQs). One can then use the boosted top (which can be tagged efficiently using jet-substructure techniques) and high-$p_{\mathrm{T}}$ $\tau$ leptons to search for these LQs. We consider two search channels with either one or two taus along with at least one hadronically decaying boosted top quark. We estimate the high luminosity LHC (HL-LHC) search prospects of these LQs by considering both symmetric and asymmetric pair and single production processes. Our selection criteria are optimized to retain events from both pair and single production processes. The combined signal has better prospects than the traditional searches. We include new three-body single production processes to enhance the single production contributions to the combined signal. We identify the interference effect that appears in the dominant single production channel of charge-$1/3$ scalar LQ ($S^{1/3}$). This interference is constructive if $S^{1/3}$ is a weak-triplet and destructive for a singlet one. As a result, their LHC prospects differ appreciably.

Recent progress on muon $g-2$ measurement prompts one to take it even more seriously. In the general two Higgs doublet model that allows extra Yukawa couplings, we take a simplified approach of single enhanced coupling. We fix the charged lepton flavor violating coupling, ${\rho }_{\tau \mu }={\rho }_{\mu \tau }$, via the one-loop mechanism, for illustrative masses of the heavy scalar $H$ and pseudoscalar $A$, where we assume $m_A=m_{H^{+}}$. Since extra top Yukawa couplings are plausibly the largest, we turn on ${\rho }_{tt}$ and find that LHC search for $gg\to H,A\to \tau \mu$ gives a more stringent bound than from $\tau \to \mu \gamma$ with the two-loop mechanism. Turning on a second extra top Yukawa coupling, ${\rho }_{tc}$, can loosen the bound on ${\rho }_{tt}$, but LHC constraints can again be more stringent than from $B\to D\mu \nu$ versus $De\nu$ universality. This means that evidence for $H,A\to \tau \mu$ may yet emerge with full LHC Run 2 data, while direct search for ${\tau }^{\pm }{\mu }^{\mp }b{W}^{+}$ or $t\overline{c}b{W}^{+}$ (plus conjugate) may also bear fruit.

We demonstrate that the recent measurement of the anomalous magnetic moment of the muon and dark matter can be simultaneously explained within the minimal supersymmetric standard model. Dark matter is a mostly bino state, with the relic abundance obtained via coannihilations with either the sleptons or wino. The most interesting regions of parameter space will be tested by the next generation of dark matter direct detection experiments.

We consider a simple extension of the standard model, which could give a solution for its $CP$ issues such as the origin of both Cabibbo-Kobayashi-Maskawa (CKM) and Pontecorvo-Maki-Nakagawa-Sakata (PMNS) phases and the strong $CP$ problem. The model is extended with singlet scalars which allow the introduction of the Peccei-Quinn symmetry and could cause spontaneous $CP$ violation to result in these phases at low energy regions. The singlet scalars could give a good inflaton candidate if they have a suitable nonminimal coupling with the Ricci scalar. $CP$ issues and inflation could be closely related through these singlet scalars in a natural way. In a case where the inflaton is a mixture of the singlet scalars, we study reheating and leptogenesis as notable phenomena affected by the fields introduced in this extension.

We propose a method to use lattice QCD to compute the Borel transform of the vacuum polarization function appearing in the Shifman-Vainshtein-Zakharov QCD sum rule. We construct the spectral sum corresponding to the Borel transform from two-point functions computed on the Euclidean lattice. As a proof of principle, we compute the $s\overline{s}$ correlators at three lattice spacings and take the continuum limit. We confirm that the method yields results that are consistent with the operator product expansion in the large Borel mass region. The method provides a ground on which the OPE analyses can be directly compared with nonperturbative lattice computations.

We perform a global QCD analysis of unpolarized parton distributions within a Bayesian Monte Carlo framework, including the new $W$-lepton production data from the STAR Collaboration at RHIC and Drell-Yan dimuon data from the SeaQuest experiment at Fermilab. We assess the impact of these two new measurements on the light antiquark sea in the proton and the $\overline{d}-\overline{u}$ asymmetry in particular. The SeaQuest data are found to significantly reduce the uncertainty on the $\overline{d}/\overline{u}$ ratio at large parton momentum fractions $x$, strongly favoring an enhanced $\overline{d}$ sea up to $x\approx 0.4$, in general agreement with nonperturbative calculations based on chiral symmetry breaking in QCD.

Within the framework of the local hidden gauge formalism, we have reanalyzed the hidden-charm vector-vector meson $D^{*}{\overline{D}}^{*}$, $K^{*}{\overline{K}}^{*}$, and $\rho \rho$ interactions with the quantum numbers $I(J^P)=1(1^{+})$. The estimation indicates that $D^{*}{\overline{D}}^{*}$ system could form a bound state around 4010 MeV. By comparing our theoretical estimation with the BESIII measurements of the $e^{+}{e}^{-}\to (D^{*}{\overline{D}}^{*}{)}^{\pm }{\pi }^{\mp }$ and $e^{+}{e}^{-}\to (D^{*}{\overline{D}}^{*}{)}^0{\pi }^0$ reactions at $\sqrt{s}=4.26\mathrm{GeV}$, we find that the enhancement structure of the $Z_c(4025)$ in the $D^{*}{\overline{D}}^{*}$ invariant mass distribution observed by BESIII could be interpreted by a shallow $D^{*}{\overline{D}}^{*}$ bound state.

We study the empirical realization of the memory effect in Yang-Mills theory with an axionlike particle, especially in view of the classical vs quantum nature of the theory. We solve for the coupled equations of motion iteratively in the axionic contributions and explicitly display the gauge-invariant effects in terms of field strengths. We apply our results in the context of heavy-ion collisions, in the thin nuclear sheet limit, and point out that a probe particle traversing radiation train acquires a longitudinal null memory kick in addition to the usual transverse kick.

We carry out the canonical analysis of a covariant version of unimodular gravity in terms of the connection representation. We then proceed to quantize this theory by implementing the Dirac procedure. We confirm whether and how the Kodama state, which is a solution of quantum general relativity, can be extended into covariant unimodular gravity. Finally, we discuss the difference of quantum states between covariant unimodular gravity, the original unimodular gravity, and general relativity.

Black hole spectroscopy is a powerful tool to probe the Kerr nature of astrophysical compact objects and their environment. The observation of multiple ringdown modes in gravitational waveforms could soon lead to high-precision gravitational spectroscopy, so it is critical to understand if the quasinormal mode spectrum is stable against perturbations. It was recently shown that the pseudospectrum can shed light on the spectral stability of black hole quasinormal modes. We study the pseudospectrum of Reissner-Nordström spacetimes and we find a spectral instability of scalar and gravitoelectric quasinormal modes in subextremal and extremal black holes, extending similar findings for the Schwarzschild spacetime. The asymptotic structure of pseudospectral contour levels is the same for scalar and gravitoelectric perturbations. By making different gauge choices in the hyperboloidal slicing of the spacetime, we find that the broad features of the pseudospectra are remarkably gauge independent. The gravitational-led and electromagnetic-led quasinormal modes of extremal Reissner-Nordström black holes exhibit “strong” isospectrality: not only their spectrum coincides, but the whole pseudospectrum is the same for both classes of perturbations. We observe that a conformal duality between the extremal horizon and spacetime boundaries at infinity is responsible for such strong isospectrality property.

Models of turbulent flows require the resolution of a vast range of scales, from large eddies to small-scale features directly associated with dissipation. As the required resolution is not within reach of large scale numerical simulations, standard strategies involve a smoothing of the fluid dynamics, either through time averaging or spatial filtering. These strategies raise formal issues in general relativity, where the split between space and time is observer dependent. To make progress, we develop a new covariant framework for filtering/averaging based on the fibration of spacetime associated with fluid elements and the use of Fermi coordinates to facilitate a meaningful local analysis. We derive the resolved equations of motion, demonstrating how “effective” dissipative terms arise because of the coarse-graining, and paying particular attention to the thermodynamical interpretation of the resolved quantities. Finally, as the smoothing of the fluid dynamics inevitably leads to a closure problem, we propose a new closure scheme inspired by recent progress in the modeling of dissipative relativistic fluids, and crucially, demonstrate the linear stability of the proposed model.

We study the fully nonlinear dynamics of the spherically symmetric black hole spontaneous scalarization in Einstein Maxwell scalar theory with coupling function $f(\varphi )=e^{-b{\varphi }^2}$, which can transform usual Reissner-Nordström anti–de Sitter (RN-AdS) black holes into hairy black holes. Fixing the Arnowitt-Deser-Misner mass of the system, the initial scalar perturbation will destroy the original RN-AdS black hole and turn it into a spherically symmetric hairy black hole provided that the constant $-b$ in the coupling function and the charge of the original black hole are sufficiently large, while the cosmological constant is small enough. In the scalarization process, we observe that the black hole irreducible mass initially increases exponentially, then it approaches to and finally saturates at a finite value. Choosing stronger coupling and larger black hole charge, we find that the black hole mass exponentially grows earlier and it takes longer time for a hairy black hole to be developed and stabilized. We further examine phase structure properties in the scalarization process and confirm the observations in the nonlinear dynamical study.

Spherically, plane, or hyperbolically symmetric spacetimes with an additional hypersurface orthogonal Killing vector are often called “static” spacetimes even if they contain regions where the Killing vector is nontimelike. It seems to be widely believed that an energy-momentum tenor for a matter field compatible with these spacetimes in general relativity is of the Hawking-Ellis type I everywhere. We show in arbitrary $n(\ge 3)$ dimensions that, contrary to popular belief, a matter field on a Killing horizon is not necessarily of type I but can be of type II. Such a type-II matter field on a Killing horizon is realized in the Gibbons-Maeda-Garfinkle-Horowitz-Strominger black hole in the Einstein-Maxwell-dilaton system and may be interpreted as a mixture of a particular anisotropic fluid and a null dust fluid.

We study the role of the Standard Model Higgs condensate, formed during cosmological inflation, in the epoch of reheating that follows. We focus on the scenario where the inflaton decays slowly and perturbatively, so that there is a long period between the end of inflation and the beginning of radiation domination. The Higgs condensate decays nonperturbatively during this period, and we show that it heats the primordial plasma to much higher temperatures than would result from the slowly decaying inflaton alone. We discuss the effect of this hot plasma on the thermalization of the inflaton’s decay products, and study its phenomenological implications for the formation of cosmological relics like dark matter, with associated isocurvature fluctuations, and the restoration of the electroweak and Peccei-Quinn symmetries.

We discuss phenomenological viability of a novel inflationary model in the minimal gauge mediated supersymmetry breaking scenario. In this model, cosmic inflation is realized in the flat direction along the messenger supermultiplets and a natural dark matter candidate is the gravitino from the out-of-equilibrium decay of the binolike neutralino at late times, which is called the super-WIMP scenario. The produced gravitino is warmish and can have a large free-streaming length; thus the cusp anomaly in the small scale structure formation may be mitigated. We show that the requirement of the Standard Model Higgs boson mass to be $m_{h^0}=125.1\mathrm{GeV}$ gives a relation between the spectrum of the cosmic microwave background and the messenger mass $M$. We find, for the $e$-folding number $N_e=60$, the Planck 2018 constraints (TT, TE, $\mathrm{EE}+\mathrm{lowE}+\mathrm{lensing}+\mathrm{BK}15+\mathrm{BAO}$, 68% confidence level) give $M>3.64\times {10}^7\mathrm{GeV}$. The gravitino dark matter mass is $m_{3/2}<5.8\mathrm{GeV}$ and the supersymmetry breaking scale $\mathrm{\Lambda }$ is found to be in the range $(1.28–1.33)\times {10}^6\mathrm{GeV}$. Future cosmic microwave background observation is expected to give tighter constraints on these parameters.

In the current $3\nu$ paradigm, neutrino flavor oscillations probe three mixing angles $({\theta }_{12},{\theta }_{23},{\theta }_{13})$, one $CP$-violating phase $\delta$, and two independent differences between the squared masses $m_i^2$, that can be chosen as $\delta m^2=m_2^2-m_1^2>0$ and $\mathrm{\Delta }{m}^2=m_3^2-(m_1^2+m_2^2)/2$, where $\mathrm{sign}(\mathrm{\Delta }{m}^2)=+(-)$ for normal (inverted) mass ordering. Absolute $\nu$ masses can be probed by the effective mass $m_{\beta }$ in beta decay, by the total mass $\mathrm{\Sigma }$ in cosmology and—if neutrinos are Majorana—by another effective mass $m_{\beta \beta }$ in neutrinoless double beta decay. Within an updated global analysis of oscillation and nonoscillation data, we constrain these $3\nu$ parameters, both separately and in selected pairs, and highlight the concordance or discordance among different constraints. Five oscillation parameters $(\delta m^2,|\mathrm{\Delta }{m}^2|,{\theta }_{12},{\theta }_{23},{\theta }_{13})$ are consistently measured, with an overall accuracy ranging from $\sim 1\%$ for $|\mathrm{\Delta }{m}^2|$ to $\sim 6\%$ for ${\sin }^2{\theta }_{23}$ (due to its persisting octant ambiguity). We find overall hints for normal ordering (at $\sim 2.5\sigma$), as well as for ${\theta }_{23}<\pi /4$ and for $\sin \delta <0$ (both at 90% C.L.), and discuss some tensions among different datasets. Concerning nonoscillation data, we include the recent KATRIN constraints on $m_{\beta }$, and we combine the latest ${}^{76}\mathrm{Ge}$, ${}^{130}\mathrm{Te}$ and ${}^{136}\mathrm{Xe}$ bounds on $m_{\beta \beta }$, accounting for nuclear matrix element covariances. We also discuss some variants related to cosmic microwave background (CMB) anisotropy and lensing data, which may affect cosmological constraints on $\mathrm{\Sigma }$ and hints on $\mathrm{sign}(\mathrm{\Delta }{m}^2)$. The default option, including all Planck results, irrespective of the so-called lensing anomaly, sets upper bounds on $\mathrm{\Sigma }$ at the level of $\sim {10}^{-1}\mathrm{eV}$, and further favors normal ordering up to $\sim 3\sigma$. An alternative option, that includes recent ACT results plus other independent results (from WMAP and selected Planck data) globally consistent with standard lensing, is insensitive to the ordering but prefers $\mathrm{\Sigma }\sim \mathrm{few}\times {10}^{-1}\mathrm{eV}$, with different implications for $m_{\beta }$ and $m_{\beta \beta }$ searches. In general, the unfinished fabric of the $3\nu$ paradigm appears to be at the junction of diverse searches in particle and nuclear physics, astrophysics and cosmology, whose convergence will be crucial to achieve a convincing completion.

Bosonic super–weakly interacting massive particles (WIMPs), including pseudoscalar and vector particles, are dark-matter candidates. To date, many underground experiments searches for super-WIMPs have been performed in the mass range of a few $\mathrm{keV}/c^2$ to $1\mathrm{MeV}/c^2$. All these searches utilize the absorption process of a super-WIMP by a target atom in the detector, which is similar to the photoelectric effect. We consider another process—namely, a Compton-like process. As an example, we compare the cross section of a germanium atom for the absorption process with that of a Compton-like process. Our findings indicate that the cross section for the Compton-like process becomes dominant relative to that for the absorption process for mass above approximately $150\mathrm{keV}/c^2$ for both pseudoscalar and vector super-WIMPs. In particular, the cross section for the Compton-like process for a vector super-WIMP becomes increasingly greater than that for the absorption process by 1 to 2 orders of magnitude in the $400\mathrm{keV}/c^2$ to $1\mathrm{MeV}/c^2$ mass range, respectively. By including the Compton-like process, which has not been used in any other super-WIMP search experiments, the experimental upper limits can be improved.

The nonperturbative functional renormalization group equation depends on the choice of a regulator function, whose main properties are a “coarse-graining scale” $k$ and an overall dimensionless amplitude $a$. In this paper we shall discuss the limit $a\to 0$ with $k$ fixed. This limit is closely related to the pseudoregulator that reproduces the beta functions of the $\overline{\mathrm{MS}}$ scheme that we studied in a previous paper. It is not suitable for precision calculations but it appears to be useful to eliminate the spurious breaking of symmetries by the regulator, both for nonlinear models and within the background field method.

The holographic principle implies that quantum field theory (QFT) overcounts the number of independent degrees of freedom in quantum gravity. An argument due to Cohen, Kaplan, and Nelson (CKN) suggests that the number of degrees of freedom well described by QFT is even smaller than required by holographic bounds, and CKN interpreted this result as indicative of a correlation between the UV and IR cutoffs on QFT. Here, we consider an alternative interpretation in which the QFT degrees of freedom are depleted as a function of scale. We use a simple recipe to estimate the impact of depleted densities of states on precision observables, including the Lamb shift and lepton $g-2$. Although these observables are not sensitive to the level of depletion motivated by gravitational considerations, the phenomenological exercises also provide an interesting test of quantum field theory that is independent of underlying quantum gravity assumptions. A depleted density of states can also render the QFT vacuum energy UV insensitive, reconciling the success of QFT in describing ordinary particle physics processes and its apparent failure in predicting the cosmological constant.