We present a construction of $\kappa$-deformed complex scalar field theory with the objective of shedding light on the way discrete symmetries and $CPT$ invariance are affected by the deformation. Our starting point is the observation that, in order to have an appropriate action of Lorentz symmetries on antiparticle states, these should be described by four-momenta living on the complement of the portion of the de Sitter group manifold to which $\kappa$-deformed particle four-momenta belong. Once the equations of motions are properly worked out from the deformed action, we obtain that the particle and antiparticle are characterized by different mass-shell constraints, leading to a subtle form of departure from $CPT$ invariance. The remaining part of our work is dedicated to a detailed description of the action of deformed Poincaré and discrete symmetries on the complex field.

We use a new mechanism for generating a Fayet-Iliopoulos term in supergravity, which is not associated to an R-symmetry, to construct a semirealistic theory of slow-roll inflation for a theory with the same Kähler potential and superpotential as the Kachru-Kallosh-Linde-Trivedi string background (without anti-D3 branes). In our model, supersymmetry must be broken at a high scale in a hidden sector to ensure that the cutoff of the effective field theory is above the Hubble scale of inflation. The gravitino has a super-EeV mass and supersymmetry breaking is communicated to the observable sector through gravity mediation. Some mass scales of the supersymmetry-breaking soft terms in the observable sector can be parametrically smaller than the SUSY breaking scale. If a string realization of the new Fayet-Iliopoulos term were found, our model could be the basis for a low energy effective supergravity description of realistic superstring models of inflation.

The Standard Model Extension (SME) is a generic parametrization for Lorentz violation and the phenomenological consequences of the minimal gravity sector of the SME are usually studied using a post-Newtonian expansion that requires spacetime to be asymptotically flat. However, there is a term in this sector for which these approximations are unable to make predictions; this is known as the $t$ puzzle. The present paper studies a model of spontaneous Lorentz violation in the minimal gravity sector of the SME in a static and spherically symmetric situation, when no additional matter fields are present. It is shown that, under the above mentioned assumptions, $t$ is the only term in the minimal gravity sector for which no asymptotically flat solutions exist. This stems from the fact that the $t$ term fixes the asymptotic behavior of all the pieces of the curvature tensor.

It was found recently that the anisotropies in the homogeneous Bianchi I cosmology considered within the context of a specific Horndeski theory are damped near the initial singularity instead of being amplified. In this work we extend the analysis of this phenomenon to cover the whole Horndeski family. We find that the phenomenon is absent in the K-essence and/or kinetic gravity braiding theories, where the anisotropies grow as one approaches the singularity. The anisotropies are damped at early times only in more general Horndeski models whose Lagrangian includes terms quadratic and cubic in second derivatives of the scalar field. Such theories are often considered as being inconsistent with the observations because they predict a nonconstant speed of gravitational waves. However, the predicted value of the speed at present can be close to the speed of light with any required precision; hence the theories actually agree with the present time observations. We consider two different examples of such theories, both characterized by a late self-acceleration and an early inflation driven by the nonminimal coupling. Their anisotropies are maximal at intermediate times and approach zero at early and late times. The early inflationary stage exhibits an instability with respect to inhomogeneous perturbations, suggesting that the initial state of the Universe should be inhomogeneous. However, more general Horndeski models may probably be stable.

The cosmic infrared background (CIB) sourced by infrared emission from dusty star-forming galaxies is a valuable source of information on the star formation history of the Universe. In measurements of the millimeter sky at frequencies higher than $\sim 300\mathrm{GHz}$, the CIB and thermal emission from Galactic dust dominate. Insufficient understanding of the CIB contribution at lower frequencies can hinder efforts to measure the kinetic Sunyaev-Zeldovich spectrum on small scales as well as new physics that affects the damping tail of the cosmic microwave background (CMB). The Planck satellite has measured with high fidelity the CIB at 217, 353, 545 and 857 GHz. On very large scales, this measurement is limited by our ability to separate the CIB from Galactic dust, but on intermediate scales, the measurements are limited by sample variance in the underlying matter field traced by the CIB. We show how significant improvements (20–100%) can be obtained on parameters of star formation models by cross-correlating the CIB (as measured from existing Planck maps or upcoming CCAT-prime maps) with upcoming mass maps inferred from gravitational lensing of the CMB. This improvement comes from improved knowledge of the redshift distribution of star-forming galaxies as well as through the use of the unbiased matter density inferred from CMB lensing mass maps to cancel the sample variance in the CIB field. We also find that further improvements can be obtained on CIB model parameters if the cross-correlation of the CIB with CMB lensing is measured over a wider area while restricting the more challenging CIB autospectrum measurement to the cleanest 5% of the sky.

We introduce simplified models for enhancements in the matter power spectrum at small scales and study their implications for dark matter substructure and gravitational observables. These models capture the salient aspects of a variety of early Universe scenarios that predict enhanced small-scale structure, such as axionlike particle dark matter, light vector dark matter, and epochs of early matter domination. We use a model-independent, semianalytic treatment to map bumps in the matter power spectrum to early forming subsolar mass dark matter halos and estimate their evolution, disruption, and contribution to the substructure of clusters and galaxies at late times. We discuss the sensitivity of gravitational observables, including pulsar timing arrays and caustic microlensing, to both the presence of bumps in the power spectrum and variations in their basic properties.

GW170817 has provided valuable constraints on the equations of state of merging binary neutron stars, which can be considered as the most probable candidate for the source of gravitational waves. On the other hand, these natural laboratories of extreme temperature and density may lead to the estimation of some exotic matter like deconfined quark matter in their cores. In this paper, we investigate the neutron star matter equation of state (EoS) with the lowest order constrained variational (LOCV) method considering the excluded volume effect (VLOCV) for nucleons to compute the tidal deformability of binary neutron star mergers (BNSMs). Within this approach, the size of nucleons makes the EoS so stiff that requires a phase transition in order to avoid causality violation. Therefore, this phase transition may lead to the appearance of the third family of compact stars including “twin star” configurations. Our EoS models are confronted with observations from GW170817, GW190814, GW190425, and also NICER. We find out that regarding all these constraints, the EoS models having the transition $\text{pressure}\approx 30–100\mathrm{MeV}/{\mathrm{fm}}^3$ and the energy density discontinuity $\mathrm{\Delta }ϵ\lesssim 300\mathrm{MeV}/{\mathrm{fm}}^3$ are preferable.

We consider the phenomenological implications of charged scalar extensions of the Standard Model (SM) Higgs sector in addition to effective field theory (EFT) couplings of this new state to SM matter. We perform a detailed investigation of modifications of loop-induced decays of the 125 GeV Higgs boson, which receives corrections from the propagating charged scalars alongside one-loop EFT operator insertions and demonstrate that the interplay of $H\to \gamma \gamma$ and $H\to Z\gamma$ decays can be used to clarify the additional states phenomenology in case a discovery is made in the future. In parallel, EFT interactions of the charged Higgs can lead to a decreased sensitivity to the virtual presence of charged Higgs states, which can significantly weaken the constraints that are naively expected from the precisely measured $H\to \gamma \gamma$ branching ratio. Again $H\to Z\gamma$ measurements provide complementary sensitivity that can be exploited in the future.

The Georgi-Machacek (GM) model is used to motivate and interpret LHC searches for doubly charged scalars decaying to vector bosons pairs. The doubly charged scalars are part of a degenerate fermiophobic custodial fiveplet with states $H_5^{\pm \pm }$, $H_5^{\pm }$, and $H_5^0$ and common mass $m_5$. The GM model has been extensively studied at the LHC for $m_5>200\mathrm{GeV}$, but there is a largely unprobed region of parameter space from $120\mathrm{GeV}<m_5<200\mathrm{GeV}$ where light doubly charged scalars could exist. This region has been neglected by experimental searches due in part to the lack of a benchmark for $m_5<200\mathrm{GeV}$. In this paper we propose a new “low-$m_5$” benchmark for the GM model, defined for $m_5\in (50,550)\mathrm{GeV}$, and characterize its properties. We apply all existing experimental constraints and summarize the phenomenology of the surviving parameter space. We show that the benchmark populates almost the entirety of the relevant allowed parameter plane for $m_5$ below 200 GeV and satisfies the constraints from the 125 GeV Higgs boson signal strengths. We compute the 125 GeV Higgs boson’s couplings to fermion and vector boson pairs and show that they are always enhanced in the benchmark relative to those in the Standard Model. We also compute the most relevant production cross sections for $H_5$ at the LHC, including Drell-Yan production of $H_5$ pairs. The process $pp\to H\to H_5{H}_5$ contributes in a small region of parameter space, but is small compared to the Drell-Yan production cross section. Finally we compute the branching ratios of $H_5^0\to \gamma \gamma$ and $H_5^{\pm }\to W^{\pm }\gamma$. The width-to-mass ratio of each of the $H_5$ states is below 1% over the entire benchmark, so that the narrow-width approximation is well justified.

Interferences are not positive-definite and therefore they can change sign over the phase space. If the contributions of the regions where the interference is positive and negative nearly cancel each other, interference effects are hard to measure. In this paper, we propose a method to quantify the ability of an observable to separate an interference positive and negative contributions and therefore to revive the interference effects in measurements. We apply this method to the anomalous gluon operator in the SMEFT for which the interference suppression is well-known. We show that we can get, for the first time, constraints on its coefficient using the interference only similar to those obtained by including the square of the new physics amplitude.

As we amass more LHC data, we continue to search for new and improved methods of visualizing search results, in ways that are as model independent as possible. The simplified limits framework is an approach developed to recast limits on searches for narrow resonances in terms of products of branching ratios (BRs) corresponding to the resonance’s production and decay modes. In this work, we extend the simplified limits framework to a multidimensional parameter space of BRs, which can be used to unfold an ambiguity in the simplified parameter $\zeta$ introduced when more than one channel contributes to the production of the resonance. It is also naturally applicable to combining constraints from experimental searches with different observed final states. Constraints can be visualized in a three-dimensional space of branching ratios by employing ternary diagrams, triangle plots which utilize the inherent unitarity of the sum of the resonance’s BRs. To demonstrate this new methodology, we recast constraints from recent ATLAS searches in diboson final states for spin-0, -1, and -2 narrow resonances into constraints on the resonance’s width-to-mass ratio and display them in the space of relevant branching ratios. We also demonstrate how to generalize the method to cases where more than three branching ratios are relevant by using $N$-simplex diagrams, and we suggest a broader application of the general method to digital datasets.

The flavor anomalies reported in $R_K$, $R_{K^{*}}$, $P_5^{\prime }$, and $\mathcal{B}(B_s\to \varphi {\mu }^{+}{\mu }^{-})$ indicate lepton flavor universality violation in $b\to s{l}^{+}{l}^{-}$ quark level transition decays. The deviation from the standard model prediction reported in the underlying flavor observables currently stands at the level of $2.5\sigma$, $2.4\sigma$, $3.3\sigma$, and $3.7\sigma$, respectively. In this context, we perform an angular analysis of the four-body differential decay of $B_s\to f_2^{\prime }(1525)(\to K^{+}{K}^{-}){\mu }^{+}{\mu }^{-}$ in a model independent effective field theory framework. The decay mode $B_s\to f_2^{\prime }(1525)l^{+}{l}^{-}$ undergoes similar $b\to s$ neutral current quark level transition and, in principle, can provide complementary information regarding lepton flavor universality violation in $b\to s{l}^{+}{l}^{-}$ quark level transition decays. We give predictions of various physical observables such as the branching ratio, the longitudinal polarization fraction, the forward-backward asymmetry, the angular observables $P_1$, $P_2$, $P_4^{\prime }$, $P_5^{\prime }$, and also the lepton flavor sensitive observables such as the ratio of branching ratio $R_{f_2^{\prime }}$, $Q_{F_L}$, $Q_{A_{FB}}$, $Q_1$, $Q_2$, $Q_4^{\prime }$, $Q_5^{\prime }$ for the $B_s\to f_2^{\prime }(1525)(\to K^{+}{K}^{-}){\mu }^{+}{\mu }^{-}$ decay mode in the standard model and in the presence of several one-dimensional and two-dimensional new physics scenarios.

We propose a novel simulation strategy for Yang-Mills theories with a complex coupling, based on the Lefschetz thimble decomposition. We envisage that the approach developed in the present work can also be adapted to QCD at finite density and real-time simulations. Simulations with Lefschetz thimbles offer a potential solution to sign problems in Monte Carlo calculations within many different models with complex actions. We discuss the structure of generalized Lefschetz thimbles for pure Yang-Mills theories with a complex gauge coupling $\beta$ and show how to incorporate the gauge orbits. We propose to simulate such theories on the union of the tangential manifolds to the relevant Lefschetz thimbles attached to the critical manifolds of the Yang-Mills action. We demonstrate our algorithm on a ($1+1$)-dimensional U(1) model and discuss how, starting from the main thimble result, successive subleading thimbles can be taken into account via a reweighting approach. While we face a residual sign problem, our novel approach performs exponentially better than the standard reweighting approach.

The impact of momentum anisotropy on the heavy quark transport coefficients due to collisional and radiative processes in the QCD medium has been studied within the ambit of kinetic theory. Anisotropic aspects (momentum) are incorporated into the heavy quark dynamics through the nonequilibrium momentum distribution function of quarks, antiquarks, and gluons. These nonequilibrium distribution functions that encode the physics of momentum anisotropy and turbulent chromo-fields are obtained by solving the ensemble-averaged diffusive Vlasov-Boltzmann equation. The momentum dependence of heavy quark transport coefficients in the medium is seen to be sensitive to the strength of the anisotropy for both collisional and radiative processes. In addition, the collisional and radiative energy loss of the heavy quark in the anisotropic hot QCD medium is analyzed. The effects of anisotropy on the drag and diffusion coefficients are observed to have a visible impact on the nuclear suppression factor both at the RHIC and LHC.

We study Landau gauge gluon propagators in two-color QCD at a finite quark chemical potential (${\mu }_q$) and temperature ($T$). We include medium polarization effects at the one loop by quarks into massive gluon propagators and compare the analytic results with the available lattice data. We particularly focus on the high density phase of color-singlet diquark condensates whose critical temperature is $\sim 100\mathrm{MeV}$ with a weak dependence on ${\mu }_q$. At zero temperature, the color singlet condensates protect the IR limit of electric and magnetic gluon propagators from the medium screening effects. At a finite temperature, this behavior remains true for the magnetic sector, but the electric screening mass should be generated by thermal, and hence gapless, particles which are unbound from the diquark condensates. Treating thermal excitations as quasiquarks, we found that the electric screening develops too fast as compared to the lattice results. Beyond the critical temperature for diquark condensates, the analytic results are consistent with the lattice results.

We present an analysis of the proton mass radius by studying the $t$ dependence of the differential cross sections of the vector meson photoproductions near the thresholds. At low energy, the photoproduction of a quarkonium off the proton is connected to the scalar gravitational form factor of the proton, which is sensitive to the proton mass distribution from the quantum chromodynamics trace anomaly. Under an assumption of the scalar form factor of dipole form, the proton mass radius is extracted via the near-threshold photoproduction data of $\mathrm{J}/\psi$, $\varphi$, and $\omega$ vector mesons. The average value of the proton mass radius is estimated to be $\sqrt{⟨R_{\mathrm{m}}^2⟩}=0.67\pm 0.03\mathrm{fm}$, with the dipole cutoff $m_{\mathrm{s}}=1.01\pm 0.04\mathrm{GeV}$.

At the end of the Hawking evaporation the horizon of a black hole enters a physical region where quantum gravity cannot be neglected. The physics of this region has not been much explored. We characterize its physics and introduce a technique to study it.

We discuss numerically the nonperturbative effects in exponential random graphs which are analogue of eigenvalue instantons in matrix models. The phase structure of exponential random graphs with chemical potential for $C_4$ ${\mu }_4$ and degree preserving constraint is clarified. The first order phase transition at critical value of chemical potential for $C_4$ ${\mu }_4^{\mathrm{RRG}}$ into bipartite phase with a formation of fixed number of bipartite clusters is found for ensemble of random regular graphs (RRG). We consider the similar phase transition in mean field version of combinatorial quantum gravity based of the Ollivier graph curvature for RRG supplemented with hard-core constraint and show that a order of a phase transition at ${\mu }_4^{\mathrm{CRRG}}$ and the structure of emerging phase depend on a vertex degree $d$ in RRG. For $d=3$ the bipartite closed ribbon emerges at ${\mu }_4>{\mu }_4^{\mathrm{CRRG}}$ while for $d>3$ the ensemble of isolated or weakly interacting hypercubes supplemented with the bipartite closed ribbon gets emerged at the first order phase transition with a clear-cut hysteresis. If the additional connectedness condition is imposed the phase at ${\mu }_4>{\mu }_4^{\mathrm{CRRG}}$ gets identified as the closed chain of weakly coupled hypercubes. Since the ground state of isolated hypercube is the thermofield double we suggest that the dual holographic picture involves multiboundary wormholes. Treating RRG as a model of a Hilbert space for a interacting many-body system we discuss the patterns of the Hilbert space fragmentation at the phase transition. We also briefly comment on a possible relation of the found phase transition to the problem of holographic interpretation of a partial deconfinement transition in the gauge theories.

The role of local higher-twist ($\tau >3$) spin-$1/2$ fermionic operators of the strongly coupled $\mathcal{N}=4$ supersymmetric Yang-Mills theory on the symmetric and antisymmetric deep inelastic scattering structure functions is investigated. The calculations are carried out in terms of the duality between $\mathcal{N}=4$ SYM theory and type IIB supergravity on ${\mathrm{AdS}}_5\times S^5$. Particularly, we explicitly obtain the structure functions for single-trace spin-$1/2$ fermionic operators in the ${\mathbf{20}}^{*}$ and ${\mathbf{60}}^{*}$ irreducible representations of $SU(4{)}_R$, corresponding to twists 4 and 5, respectively. We also calculate the contributions of other single-trace spin-$1/2$ fermionic operators in the $\mathbf{4}$, $\mathbf{20}$ and $\mathbf{60}$ irreducible representations of $SU(4{)}_R$. New important effects are found in comparison with the minimal twist ($\tau =3$) case, and they are studied thoroughly.

We analyze the constraints on four-derivative corrections to 5d Einstein-Maxwell theory from the black hole weak gravity conjecture (WGC). We calculate the leading corrections to the extremal mass of asymptotically flat 5d charged solutions as well as 4d Kaluza-Klein compactifications. The WGC bounds from the latter, interpreted as 4d dyonic black holes, are found to be strictly stronger. As magnetic graviphoton charge lifts to a NUT-like charge in 5d, we argue that the logic of the WGC should apply to these topological charges as well and leads to new constraints on purely gravitational theories.