Based on an $e^{+}{e}^{-}$ collision data sample corresponding to an integrated luminosity of $2.93{\mathrm{fb}}^{-1}$ collected with the BESIII detector at $\sqrt{s}=3.773\mathrm{GeV}$, the first amplitude analysis of the singly Cabibbo-suppressed decay $D^{+}\to K^{+}{K}_S^0{\pi }^0$ is performed. From the amplitude analysis, the $K^{*}(892{)}^{+}{K}_S^0$ component is found to be dominant with a fraction of $(57.1\pm 2.6\pm 4.2)\%$, where the first uncertainty is statistical and the second systematic. In combination with the absolute branching fraction $\mathcal{B}(D^{+}\to K^{+}{K}_S^0{\pi }^0)$ measured by BESIII, we obtain $\mathcal{B}(D^{+}\to K^{*}(892{)}^{+}{K}_S^0)=(8.69\pm 0.40\pm 0.64\pm 0.51)\times {10}^{-3}$, where the third uncertainty is due to the branching fraction $\mathcal{B}(D^{+}\to K^{+}{K}_S^0{\pi }^0)$. The precision of this result is significantly improved compared to the previous measurement. This result also differs from most of theoretical predictions by about $4\sigma$, which may help to improve the understanding of the dynamics behind.

Many of the useful features of supergravities, such as admitting supersymmetric bosonic backgrounds governed by first-order Bogomol’nyi–Prasad–Sommerfield equations, can be realized in a much broader setting by relaxing the requirement of closure of the superalgebra beyond the level of quadratic fermion terms. The resulting pseudo-supersymmetric theories can be defined in arbitrary spacetime dimensions. We focus here on the $\mathcal{N}=1$ pseudo-supersymmetric extensions of the arbitrary-dimensional bosonic string action, which were constructed a few years ago. In this paper, we recast these in the language of double field theory. More precisely, we construct the action and the corresponding pseudo-supersymmetry transformation rules in terms of $\mathrm{O}(D)\times \mathrm{O}(D)$ covariant derivatives, and we discuss consistent truncations on manifolds with generalized $G$ structure. We thereby obtain a natural generalization of the previously known results for $\mathcal{N}=1$ supersymmetric double field theory in $D=10$ to arbitrary dimensions. As explicit examples, we discuss $\mathrm{Minkowski}\times G$ vacuum solutions and their corresponding pseudo-supersymmetry. We also briefly discuss squashed group manifold solutions, including an example with a Lorentzian signature metric on the group manifold $G$.

The Mathisson-Papapetrou-Dixon (MPD) equations describe the motion of an extended test body in general relativity. This system of equations, though, is underdetermined and has to be accompanied by constraining supplementary conditions, even in its simplest version, which is the pole-dipole approximation corresponding to a spinning test body. In particular, imposing a spin supplementary condition (SSC) fixes the center of mass of the spinning body, i.e., the centroid of the body. In the present study, we examine whether characteristic features of the centroid of a spinning test body, moving in a circular equatorial orbit around a massive black hole, are preserved under the transition to another centroid of the same physical body, governed by a different SSC. For this purpose, we establish an analytical algorithm for deriving the orbital frequency of a spinning body, moving in the background of an arbitrary, stationary, axisymmetric spacetime with reflection symmetry, for the Tulczyjew-Dixon, the Mathisson-Pirani, and the Ohashi-Kyrian-Semerák SSCs. Then, we focus on the Schwarzschild black hole background, and a power series expansion method is developed in order to investigate the discrepancies in the orbital frequencies expanded in power series of the spin among the different SSCs. Lastly, by employing the fact that the position of the centroid and the measure of the spin alters under the centroid’s transition, we impose proper corrections to the power expansion of the orbital frequencies, which allows to improve the convergence between the SSCs. Our concluding argument is that when we shift from one circular equatorial orbit to another in the Schwarzschild background, under the change of a SSC, the convergence between the SSCs holds only up to certain powers in the spin expansion, and it cannot be achieved for the whole power series.

Primordial black holes (PBHs), formed out of large overdensities in the early Universe, are a viable dark matter (DM) candidate over a broad range of masses. Ultralight, asteroid-mass PBHs with masses around ${10}^{17}\mathrm{g}$ are particularly interesting as current observations allow them to constitute the entire DM density. PBHs in this mass range emit $\sim \mathrm{MeV}$ photons via Hawking radiation which can directly be detected by the gamma ray telescopes, such as the upcoming AMEGO. In this work we forecast how well an instrument with the sensitivity of AMEGO will be able to detect, or rule out, PBHs as a DM candidate, by searching for their evaporating signature when marginalizing over the Galactic and extra-Galactic gamma-ray backgrounds. We find that an instrument with the sensitivity of AMEGO could exclude nonrotating PBHs as the only DM component for masses up to $7\times {10}^{17}\mathrm{g}$ at 95% confidence level for a monochromatic mass distribution, improving upon current bounds by nearly an order of magnitude. The forecasted constraints are more stringent for PBHs that have rotation, or which follow extended mass distributions.

The eHWC J1825-134 source is located in the southern sky and has been recently detected by the HAWC observatory. It presents an hard spectral index and its gamma-ray flux extends up to energies close to 100 TeV without significant suppression. Amongst the HAWC sources, it is the most luminous in the multi-TeV domain and therefore is one of the first that should be searched for with a neutrino telescope in the northern hemisphere. Using an updated effective area for the forthcoming KM3NeT detector, we study the possibility to detect this source within ten years of its running time. We show how the Fermi-LAT data could help in providing a morphology information on the source region. We conclude that, considering a neutrino energy threshold around 10 TeV, about a four to five sigma detection has to be expected after ten years of observations, depending on the details of the considered scenario. Finally, we also consider the case in which the emission from the HWC J1825-134 source is only partially hadronic and show that in 20 years of running time a three sigma detection is feasible.

We study observable signals from dark matter that self-annihilates via the Sommerfeld effect in dwarf spheroidal galaxies (dSphs). Since the effect of the Sommerfeld enhancement depends on the velocity of dark matter, it is crucial to determine the profile of dSphs to compute the J-factor, i.e., the line-of-sight integral of density squared. In our study we use the prior distributions of the parameters for satellite density profiles in order to determine the J-factor, making the most out of the recent developments in the N-body simulations and semianalytical modeling for the structure formation. As concrete models, we analyze fermionic dark matter that annihilates via a light scalar and wino dark matter in supersymmetric models. We find that, with the more realistic prior distributions that we adopt in this study, the J-factor of the most promising dSphs is decreased by a factor of a few, compared with earlier estimates based on noninformative priors. Nevertheless, the Cherenkov Telescope Array should be able to detect the thermal wino dark matter by pointing it toward best classical or ultrafaint dSphs for 500 hours.

The vacuum expectation value $v_s$ of a Higgs triplet field $\mathrm{\Delta }$ carrying two units of lepton number $L$ induces neutrino masses $\propto v_s$. The neutral component of $\mathrm{\Delta }$ gives rise to two Higgs particles, a pseudoscalar $A$ and a scalar $S$. The most general renormalizable Higgs potential $V$ for $\mathrm{\Delta }$ and the Standard-Model Higgs doublet $\mathrm{\Phi }$ does not permit the possibility that the mass of either $A$ or $S$ is small, of order $v_s$, while the other mass is heavy enough to forbid the decay $Z\to AS$ to comply with LEP 1 data. We present a model with additional dimension-6 terms in $V$, in which this feature is absent and either $A$ or $S$ can be chosen light. Subsequently we propose the model as a remedy to cosmological anomalies, namely the tension between observed and predicted tensor-to-scalar mode ratios in the cosmic microwave background and the different values of the Hubble constant measured at different cosmological scales. Furthermore, if $\mathrm{\Delta }$ dominantly couples to the third-generation doublet $L_{\tau }=({\nu }_{\tau },\tau )$, the deficit of ${\nu }_{\tau }$ events at IceCube can be explained. The singly and doubly charged triplet Higgs bosons are lighter than 280 GeV and 400 GeV, respectively, and could be found at the LHC.

We present a phenomenological study of the most minimal realistic $SU(5)$ model that owns its predictivity solely to the gauge symmetry and the representational content. The model is built entirely out of the fields residing in the first five lowest dimensional representations that transform nontrivially under the $SU(5)$ gauge group. It has 18 real parameters and 14 phases, all in all, to address experimental observables of the Standard Model fermions and accomplishes that via simultaneous use of three different mass generation mechanisms. Furthermore, it inextricably links the origin of the neutrino mass to the experimentally observed difference between the down-type quark and charged lepton masses. The main predictions of the model are that (i) the neutrinos are Majorana particles, (ii) one neutrino is massless, (iii) the neutrinos have normal mass ordering, and (iv) there are four new scalar multiplets at or below a 120 TeV mass scale. A one-loop analysis demonstrates that an improvement of the current $p\to {\pi }^0{e}^{+}$ partial lifetime limit by a factor of 2, 15, and 96 would require these four scalar multiplets to reside at or below the 100, 10, and 1 TeV mass scales, respectively.

In this work, we investigate the dynamical breakdown of Lorentz symmetry in 4 dimensions by the condensation of a fermionic field described by a Dirac lagrangean with a four-fermion interaction. Using the Keldysh formalism we show that the Lorentz symmetry breaking modifies the Dyson-Schwinger equations of the fermionic propagator. We analyze the nonperturbative solutions for the Dyson-Schwinger equations using the combination of the rainbow and quenched approximations and show that, in equilibrium, the Lorentz symmetry breakdown can occur in the strong coupling regime and new features arise from this approach. Finally, we analyze the contributions of temperature and chemical potential and find the respective phase diagram of the model and analyze the dependence of the critical temperature and chemical potential as functions of the coupling constant.

We investigate scattering amplitudes of the reversible $\theta$-exact Seiberg-Witten map-based noncommutative (NC) quantum electrodynamics and show explicitly the SW map invariance for all types of tree-level NCQED two-by-two processes, including Møller, Bhabha, Compton, pair annihilation, pair production, and light-by-light (LbyL: $\gamma \gamma \to \gamma \gamma )$ scatterings. We apply our NCQED results to the $\gamma \gamma \to \gamma \gamma$ and $\gamma \gamma \to {\ell }^{+}{\ell }^{-}$ exclusive channels, convoluted to the ultraperipheral lead ${}^{208}\mathrm{Pb}$ ion-ion collisions, where LbyL scattering was recently measured by the ATLAS Collaboration at the LHC. We have demonstrated that $\gamma \gamma \to \gamma \gamma$ is the more appropriate channel to probe scale ${\mathrm{\Lambda }}_{\mathrm{NC}}$. We also find that the transverse ($\phi$) dependence of the NC $\text{PbPb}(\gamma \gamma )\to {\mathrm{Pb}}^{*}{\mathrm{Pb}}^{*}\gamma \gamma$ differential cross section shows large anisotropy near the peak NC contribution for a pure spacelike NC parameter. So the $\phi$ variation of the differential cross section is likely an appropriate signature for the NCQED contributions with the pure space-space noncommutative parameter, given that enough events could be available for determining the anisotropy.

Neutrino nonstandard interactions (NSI) can be constrained using coherent elastic neutrino-nucleus scattering. We discuss here two aspects in this respect, namely effects of (i) charged current NSI in neutrino production, and (ii) CP-violating phases associated with neutral current NSI in neutrino detection. Effects of $CP$-phases require the simultaneous presence of two different flavor-changing neutral current NSI parameters. Applying these two scenarios to the COHERENT measurement, we derive limits on charged current NSI and find that more data is required to compete with the existing limits. Regarding $CP$-phases, we show how the limits on the NSI parameters depend dramatically on the values of the phases. Incidentally, the same parameters influencing coherent scattering also show up in neutrino oscillation experiments. We find that COHERENT provides complementary constraints on the set of NSI parameters that can explain the discrepancy in the best-fit value of the standard $CP$-phase obtained by T2K and $\mathrm{NO}\nu \mathrm{A}$, while the significance with which the large mixing angle (LMA)-Dark-solution is ruled out can be weakened by the presence of additional NSI parameters introduced here.

We use the Wentzel-Kramers-Brillouin (WKB) approximation to study the formation and propagation of bound states in the vicinity of a wormhole in the nonminimal derivative coupling theory of gravity. The wormhole throat connects two anti–de Sitter spacetimes. We show that when the scalar field lies in high orbital states, the corresponding potential has potential barriers that block the passage of a classical field. We investigate the behavior of the bound states trapped in the potential wells and provide the flow between the two AdS regions.

The perfect fluid solution admitting a group ${\mathrm{G}}_3$ of isometries acting on orbits ${\mathrm{S}}_2$ whose curvature has a gradient which is tangent to the fluid flow ($T$-models) are studied from a thermodynamic approach. All the admissible thermodynamic schemes are obtained, and the solutions compatible with the generic ideal gas equation of state are studied in detail. The possible physical interpretation of some previously known $T$-models is also analyzed.

Using the gravitational potential and source multipole moments bilinear in the spins, first computed to next-to-leading order (NLO) in the post-Newtonian expansion within the effective field theory (EFT) framework, we complete here the derivation of the dynamical invariants and flux-balance equations, including energy and angular momentum. We use these results to calculate spin-spin effects in the orbital frequency and accumulated phase to NLO for circular orbits. We also derive the linear momentum and center-of-mass fluxes and associated kick velocity, to the highest relevant post-Newtonian order. We explicitly demonstrate the equivalence between the quadratic-in-spin source multipoles obtained using the EFT formalism and those rederived later with more traditional tools, leading to perfect agreement for spin-spin radiative observables to NLO among both approaches.

Semiclassical processes such as production and decay of electroweak sphaleron in the Standard Model and also microscopic black hole in low scale gravity scenario typically involve large number of particles in final states. These large multiplicities can be distinctively seen in collisions of ultra-high-energy (UHE) neutrinos with $E_{\nu }\gtrsim {10}^9\mathrm{GeV}$ and nucleons in the atmosphere of the Earth. Focusing on air-shower detector array experiments including Telescope Array Experiment (TA), Pierre-Auger Observatory (Auger), we propose strategic ways to discover and analyze such events.

We present a simple scheme for solving relativistic integral equations for the partial-wave projected three-body amplitudes. Our techniques are used to solve a problem of three scalar particles with a formation of a $S$-wave two-body bound state. We rewrite the problem in a form suitable for numerical solution and then explore three solving strategies. In particular, we discuss different ways of incorporating the bound-state pole contribution in the integral equations. All of them lead to agreement with previous results obtained using finite-volume spectra of the same theory, providing further evidence of the validity of the existing finite- and infinite-volume formalism for studying three-particle systems. We discuss an analytic and numerical estimate of the systematic errors and provide numerical evidence that the methods presented allow for determination of amplitude above the three-body threshold as well. In conjunction with the previously derived finite-volume formalism, this work furthers the objective for extracting three-hadron scattering amplitudes directly from lattice QCD.

We develop a truncated Hamiltonian method to study nonequilibrium real time dynamics in the Schwinger model—the quantum electrodynamics in $D=1+1$. This is a purely continuum method that captures reliably the invariance under local and global gauge transformations and does not require a discretization of space-time. We use it to study a phenomenon that is expected not to be tractable using lattice methods: we show that the $(1+1)\mathrm{D}$ quantum electrodynamics admits the dynamical horizon violation effect which was recently discovered in the case of the sine-Gordon model. Following a quench of the model, oscillatory long-range correlations develop, manifestly violating the horizon bound. We find that the oscillation frequencies of the out-of-horizon correlations correspond to twice the masses of the mesons of the model suggesting that the effect is mediated through correlated meson pairs. We also report on the cluster violation in the massive version of the model, previously known in the massless Schwinger model. The results presented here reveal a novel nonequilibrium phenomenon in $(1+1)\mathrm{D}$ quantum electrodynamics and make a first step towards establishing that the horizon violation effect is present in gauge field theory.

It is by now well recognized that the naive application of the projection postulate on composite quantum systems can induce signalling between their constituent components, indicative of a breakdown of causality in a relativistic spacetime context. Here we introduce a necessary and sufficient condition for an ideal measurement of an observable to be nonsignalling. As well as being particularly simple, it generalizes previous no-signalling conditions in that it allows for degeneracies and can be applied to all bounded self-adjoint operators. The condition is used to establish that arbitrary sums of local observables will not signal, in accordance with our expectations from relativistic quantum field theory. On the other hand, it is shown that the measurement of the tensor product of commuting local observables, for example bipartite operators of the form $A\otimes B$, can in fact signal, contrary to the widely held belief that such measurements are always locally realizable. The implications for the notion of measurement in relativistic quantum field theory are addressed; it appears that the most straightforward application of the standard quantum formalism generically leads to violations of causality. We conclude that either the class of observables that can be measured should be restricted and/or that the naive translation of the measurement framework of quantum theory, in particular the projection postulate, to quantum field theory should be reevaluated.

We perform a Hadamard point-split renormalization of the current density $j_{\nu }$ of a charged scalar field in a Reissner–Nordström–de Sitter spacetime. We compute numerically the expectation values of the components $j_r$ and $j_t$ in the Unruh state in the exterior region and study their dependence on the field parameters and the position.

We present analogue models for the Schwarzschild and Reissner-Nordström (RN) spacetimes based on unidirectional hydrodynamic flows. We show that, with appropriate coordinate transformations, sound waves in a moving fluid propagate as scalar fields at the equatorial sections of Schwarzschild and RN black holes. The coordinate associated with the direction of the flow plays the role of the radial coordinate in standard Schwarzschild/RN coordinates, while the transversal spatial coordinate is related to the angular coordinate on each equatorial slice. The magnitude of the flow velocity is related to the mass and charge of the analogue black hole. Physical quantities like pressure and density remain finite at the analogue horizon, thereby resulting in sound waves that are well defined almost everywhere, except possibly at the analogue black hole singularity.