We present a renormalizable theory of scalars in which the low-energy effective theory contains a pseudo-Goldstone boson with a compact field space of $2\pi F$ and an approximate discrete shift symmetry ${\mathcal{Z}}_Q$ with $Q\gg 1$, yet the number of fields in the theory goes as $\log Q$. Such a model can serve as a UV completion to models of relaxions and is a new source of exponential scale separation in field theory. While the model is local in “theory space,” it appears not to have a continuum generalization (i.e., it cannot be a deconstructed extra dimension). Our framework shows that super-Planckian field excursions can be mimicked while sticking to renormalizable four-dimensional quantum field theory. We show that a supersymmetric extension is straightforwardly obtained, and we illustrate possible UV completions based on a compact extra dimension, where all global symmetries arise accidentally as a consequence of gauge invariance and five-dimensional locality.

We consider $O(N)$-symmetric bosonic ${\varphi }^4$ field theories above four dimensions, and propose a new reformulation in terms of an irreducible tensorial field with a cubic and Yukawa terms. The ${\varphi }^4$ field theory so rewritten exhibits real and nontrivial IR-stable fixed points near and below six dimension, for low values of $N$ such as $N=2$ and $N=3$. The so-defined UV completions of the $O(2)$ and $O(3)$ models hence constitute precious examples of asymptotically safe quantum field theories. The possibility of an extension of our results to five dimensions is discussed.

The flavor of cosmic neutrinos may help unveil their sources and could reveal the presence of new physics in the neutrino sector. We consider impacts of next-generation neutrino detectors, including the planned upgrade to neutrino detector, IceCube-Gen2, which is well positioned to make dramatic improvements in both flavor and spectral measurements. We show that various models in neutrino physics beyond the Standard Model, such as neutrino decay, pseudo-Dirac states, and neutrino self-scattering, may be found or strongly constrained at IceCube-Gen2 and Cubic Kilometre Neutrino Telescope. We find that the additional flavor discriminants given by Glashow resonance events and so-called “double-bang” topologies improve the ability to access the flavor of the cosmic high-energy neutrinos and probe the beyond the Standard Model physics. In addition, although details depend on source properties, Glashow resonance events have the additional feature of being able to inform us of the relative strengths of neutrino and antineutrino emission, which may help us discriminate astrophysical scenarios.

We investigate nonlinear plane-wave solutions of the classical Minkowskian Yang-Mills (YM) equations of motion. By imposing a suitable ansatz which solves Gauss’ law for the SU(3) theory, we derive solutions which consist of Jacobi elliptic functions depending on an enumerable set of elliptic modulus values. The solutions represent periodic anharmonic plane waves which possess arbitrary nonzero mass and are exact extrema of the nonlinear YM action. Among them, a unique harmonic plane wave with a nontrivial pattern in phase, spin, and color is identified. Similar solutions are present in the SU(4) case, while they are absent from the SU(2) theory.

We examine the evolution of extremal spherically symmetric black holes, developing both general theory as well as the specific cases of (charged) null dust and massless scalar field spacetimes. As matter accretes onto extremal marginally trapped tubes, they generically evolve to become nonextremal, with the initial extremal horizon bifurcating into inner and outer nonextremal horizons. At the start of this process arbitrarily slow matter accretion can cause a geometrically invariant measure of horizon growth to jump from zero to infinity. We also consider dynamical horizons that are extremal throughout their evolution and see that such spacetimes contain two extremal black hole horizons: an inner isolated one and an outer dynamical one. We compare these extremal dynamical horizons with the dynamical extreme event horizon spacetimes of Murata, Reall and Tanahashi.

Alternative theories of gravity and their solutions are of considerable importance since, at some fundamental level, the world can reveal new features. Indeed, it is suspected that the gravitational field might be nonminimally coupled to the other fields at scales not yet probed, bringing into the forefront nonminimally coupled theories. In this mode, we consider a nonminimal Einstein-Yang-Mills theory with a cosmological constant. Imposing spherical symmetry and staticity for the spacetime and a magnetic Wu-Yang ansatz for the Yang-Mills field, we find expressions for the solutions of the theory. Further imposing constraints on the nonminimal parameters, we find a family of exact solutions of the theory depending on five parameters—two nonminimal parameters, the cosmological constant, the magnetic charge, and the mass. These solutions represent magnetic monopoles and black holes in magnetic monopoles with de Sitter, Minkowskian, and anti–de Sitter asymptotics, depending on the sign and value of the cosmological constant $\mathrm{\Lambda }$. We classify completely the family of solutions with respect to the number and the type of horizons and show that the spacetime solutions can have, at most, four horizons. For particular sets of the parameters, these horizons can become double, triple, and quadruple. For instance, for a positive cosmological constant $\mathrm{\Lambda }$, there is a critical ${\mathrm{\Lambda }}_c$ for which the solution admits a quadruple horizon, evocative of the ${\mathrm{\Lambda }}_c$ that appears for a given energy density in both the Einstein static and Eddington-Lemaître dynamical universes. As an example of our classification, we analyze solutions in the Drummond-Hathrell nonminimal theory that describe nonminimal black holes. Another application is with a set of regular black holes previously treated.

We present up-to-date electroweak fits of various Randall-Sundrum (RS) models. We consider the bulk RS, deformed RS, and the custodial RS models. For the bulk RS case we find the lightest Kaluza-Klein (KK) mode of the gauge boson to be $\sim 8\mathrm{TeV}$, while for the custodial case it is $\sim 3\mathrm{TeV}$. The deformed model is the least fine-tuned of all which can give a good fit for KK masses $<2\mathrm{TeV}$ depending on the choice of the model parameters. We also comment on the fine-tuning in each case.

The minimal area for surfaces whose borders are rectangular and circular loops are calculated using the Hamilton-Jacobi (HJ) equation. This amounts to solving the HJ equation for the value of the minimal area, without calculating the shape of the corresponding surface. This is done for bulk geometries that are asymptotically anti–de Sitter (AdS). For the rectangular contour, the HJ equation, which is separable, can be solved exactly. For the circular contour an expansion in powers of the radius is implemented. The HJ approach naturally leads to a regularization which consists in locating the contour away from the border. The results are compared with the $\epsilon$-regularization which leaves the contour at the border and calculates the area of the corresponding minimal surface up to a diameter smaller than the one of the contour at the border. The results for the circular loop do not coincide if the expansion parameter is taken to be the radius of the contour at the border. It is shown that using this expansion parameter the $\epsilon$-regularization leads to incorrect results for certain solvable non-AdS cases. However, if the expansion parameter is taken to be the radius of the minimal surface whose area is computed, then the results coincide with the HJ scheme. This is traced back to the fact that in the HJ case the expansion parameter for the area of a minimal surface is intrinsic to the surface; however, the radius of the contour at the border is related to the way one chooses to regularize in the $\epsilon$-scheme the calculation of this area.

We study the implications of flavor-changing neutral currents (FCNC’s) in a model with the $SU(2{)}_l\times SU(2{)}_h\times U(1{)}_Y$ electroweak gauge symmetry for several anomalies appearing in $b\to s\ell \overline{\ell }$ induced $B$ decays in LHCb data. In this model, $SU(2{)}_l$ and $SU(2{)}_h$ govern the left-handed fermions in the first two generations and the third generation, respectively. The physical $Z$ and $Z^{\prime }$ generate the $b\to s$ transition at tree level, leading to additional contributions to the $b\to s$ semileptonic operators ${\mathcal{O}}_{9,10}$. We find that although $B_s\text{−}{\overline{B}}_s$ mixing constrains the parameters severely, the model can produce values of ${\mathcal{C}}_{9,10}^{\mathrm{NP}}$ in the range determined by Descotes-Genon et al. (Global analysis of $b\to s\ell \ell$ anomalies, arXiv:1510.04239) for this scenario to improve the global fit of observables in decays induced by the $b\to s\mu \overline{\mu }$ transition. The $Z^{\prime }$ boson in this model also generates tree-level FCNC’s for the leptonic interactions that can accommodate the experimental central value of $R_K=\mathcal{B}(B\to K\mu \overline{\mu })/\mathcal{B}(B\to Ke\overline{e})=0.75$. In this case, the model predicts sizable branching ratios for $B\to Ke\overline{\tau }$, $B\to K\tau \overline{e}$, and an enhancement of $B\to K\tau \overline{\tau }$ with respect to its standard model value.

We study the decays of the charmonium resonances $J/\psi$ and $\psi (3686)$ to the final states ${\mathrm{\Xi }}^{-}{\overline{\mathrm{\Xi }}}^{+}$, $\mathrm{\Sigma }(1385{)}^{\mp }\overline{\mathrm{\Sigma }}(1385{)}^{\pm }$ based on a single baryon tag method using data samples of $(223.7\pm 1.4)\times 10^6$ $J/\psi$ and $(106.4\pm 0.9)\times 10^6$ $\psi (3686)$ events collected with the BESIII detector at the BEPCII collider. The decay $\psi (3686)\to \mathrm{\Sigma }(1385{)}^{\mp }\overline{\mathrm{\Sigma }}(1385{)}^{\pm }$ is observed for the first time, and the measurements of the other processes, including the branching fractions and angular distributions, are in good agreement with, and much more precise than, the previously published results. Additionally, the ratios $\frac{\mathcal{B}(\psi (3686)\to {\mathrm{\Xi }}^{-}{\overline{\mathrm{\Xi }}}^{+})}{\mathcal{B}(J/\psi \to {\mathrm{\Xi }}^{-}{\overline{\mathrm{\Xi }}}^{+})}$, $\frac{\mathcal{B}(\psi (3686)\to \mathrm{\Sigma }(1385{)}^{-}\overline{\mathrm{\Sigma }}(1385{)}^{+})}{\mathcal{B}(J/\psi \to \mathrm{\Sigma }(1385{)}^{-}\overline{\mathrm{\Sigma }}(1385{)}^{+})}$ and $\frac{\mathcal{B}(\psi (3686)\to \mathrm{\Sigma }(1385{)}^{+}\overline{\mathrm{\Sigma }}(1385{)}^{-})}{\mathcal{B}(J/\psi \to \mathrm{\Sigma }(1385{)}^{+}\overline{\mathrm{\Sigma }}(1385{)}^{-})}$ are determined.

In this paper we explore contributions to nonperturbative superpotentials arising from instantons wrapping effective divisors in smooth Calabi-Yau fourfolds. We concentrate on the case of manifolds constructed as complete intersections in products of projective spaces or generalizations thereof. We systematically investigate the structure of the cone of effective (algebraic) divisors in the fourfold geometries and employ the same tools recently developed by Anderson et al. [arXiv:1507.03235] to construct more general instanton geometries than have previously been considered in the literature. We provide examples of instanton configurations on Calabi-Yau manifolds that are elliptically and $K3$ fibered and explore their consequences in the context of string dualities. The examples discussed include manifolds containing infinite families of divisors with arithmetic genus, $\chi (D,{\mathcal{O}}_D)=1$, and superpotentials exhibiting modular symmetry.

According to the Coleman-Mandula theorem, any gauge theory of gravity combined with an internal symmetry based on a Lie group must take the form of a direct product in order to be consistent with basic assumptions of quantum field theory. However, we show that an alternative gauging of a simple group can lead dynamically to a spacetime with compact internal symmetry. The biconformal gauging of the conformal symmetry of n-dimensional Euclidean space doubles the dimension to give a symplectic manifold. Examining one of the Lagrangian submanifolds in the flat case, we find that in addition to the expected $SO(n)$ connection and curvature, the solder form necessarily becomes Lorentzian. General coordinate invariance gives rise to an $SO(n-1,1)$ connection on the spacetime. The principal fiber bundle character of the original $SO(n)$ guarantees that the two symmetries enter as a direct product, in agreement with the Coleman-Mandula theorem.

We perform real-time lattice simulations of out-of-equilibrium quark production in non-Abelian gauge theory in $3+1$ dimensions. Our simulations include the backreaction of quarks onto the dynamical gluon sector, which is particularly relevant for strongly correlated quarks. We observe fast isotropization and universal behavior of quarks and gluons at weak coupling and establish a quantitative connection to previous pure glue results. In order to understand the strongly correlated regime, we perform simulations for a large number of flavors and compare them to those obtained with two light quark flavors. By doing this we are able to provide estimates of the chemical equilibration time.

Asymptotically flat black holes in $2+1$ dimensions are a rarity. We study the recently found black flower solutions (asymptotically flat black holes with deformed horizons), static black holes, rotating black holes and the dynamical black flowers (black holes with radiative gravitons) of the purely quadratic version of new massive gravity. We show how they appear in this theory and we also show that they are also solutions to the infinite order extended version of the new massive gravity, that is the Born-Infeld extension of new massive gravity with an amputated Einsteinian piece. The same metrics also solve the topologically extended versions of these theories, with modified conserved charges and the thermodynamical quantities, such as the Wald entropy. Besides these we find new conformally flat radiating type solutions to these extended gravity models. We also show that these metrics do not arise in Einstein’s gravity coupled to physical perfect fluids.

We point out that with a specific counting of states loop quantum gravity implies that black holes perform a phase transition at a certain characteristic temperature $T_C$. In this phase transition the punctures of the spin network on the stretched horizon of the black hole jump, in effect, from the vacuum to the excited states. The characteristic temperature $T_C$ may be regarded as the lowest possible temperature of the hole. From the point of view of a distant observer at rest with respect to the hole, the characteristic temperature $T_C$ corresponds to the Hawking temperature of the hole.

The theory of massive gravity proposed by Bergshoeff, Hohm and Townsend is considered in the special case of the pure irreducibly fourth-order quadratic Lagrangian. It is shown that the asymptotically locally flat black holes of this theory can be consistently deformed to “black flowers” that are no longer spherically symmetric. Moreover, we construct radiating spacetimes settling down to these black flowers in the far future. The generic case can be shown to fit within a relaxed set of asymptotic conditions as compared to the ones of general relativity at null infinity, while the asymptotic symmetries remain the same. Conserved charges as surface integrals at null infinity are constructed following a covariant approach, and their algebra represents ${\mathrm{BMS}}_3$, but without central extensions. For solutions possessing an event horizon, we derive the first law of thermodynamics from these surface integrals.

We critically assess recent claims suggesting that upper limits on the time variation of the fine-structure constant tightly constrain the coupling of a dark energy scalar field to the electromagnetic sector, and, indirectly, the violation of the weak equivalence principle. We show that such constraints depend crucially on the assumed priors, even if the dark energy was described by a dynamical scalar field with a constant equation-of-state parameter $w$ linearly coupled to the electromagnetic sector through a dimensionless coupling $\zeta$. We find that, although local atomic clock tests, as well as other terrestrial, astrophysical and cosmological data, put stringent bounds on $|\zeta |\sqrt{|w+1|}$, the time variation of the fine-structure constant cannot be used to set or to improve upper limits on $|\zeta |$ or $|w+1|$ without specifying priors, consistent with but not favored by current data, which disfavor low values of $|w+1|$ or $|\zeta |$, respectively. We briefly discuss how this might change with a new generation of high-resolution ultrastable spectrographs, such as ESPRESSO and ELT-HIRES, in combination with forthcoming missions to map the geometry of the Universe, such as Euclid, or to test the equivalence principle, such as MICROSCOPE or STEP.

Recent precise observations of cosmic rays (CRs) by AMS-02 experiment clearly show (1) harder spectra of helium and carbon compared to protons by $\propto R^{0.08}$, and (2) concave breaks in proton and helium spectra at a rigidity $R\sim 300\mathrm{GV}$. In particular the helium and carbon spectra are exactly similar, pointing to the same acceleration site. We examine possible interpretations of these features and identify a chemically enriched region, that is, superbubbles as the most probable origin of Galactic CRs in high rigidity $R>30\mathrm{GV}$. The similar spectra of CR carbon and helium further suggest that the CRs with $R>30\mathrm{GV}$ originate from the supernova ejecta in the superbubble core, mixed with comparable or less amount of interstellar medium. We predict similar spectra for heavy nuclei.

In an $SU(N)$ gauge field theory, the $n$-point Green functions, namely, propagators and vertices, transform under the simultaneous local gauge variations of the gluon vector potential and the quark matter field in such a manner that the physical observables remain invariant. In this article, we derive this intrinsically nonperturbative transformation law for the quark propagator within the system of covariant gauges. We carry out its explicit perturbative expansion up to $\mathcal{O}(g_s^6)$ and, for some terms, up to $\mathcal{O}(g_s^8)$. We study the implications of this transformation for the quark-antiquark condensate, multiplicative renormalizability of the massless quark propagator, as well as its relation with the quark-gluon vertex at the one-loop order. Setting the color factors $C_F=1$ and $C_A=0$, Landau-Khalatnikov-Fradkin transformation for the Abelian case of quantum electrodynamics is trivially recovered. We also test whether the usually employed proposals for the truncations of Schwinger-Dyson equations are consistent with what the Landau-Khalatnikov-Fradkin transformations entail for the massless quark propagator.

We consider a concise dark matter scenario in the minimal gauged $B-L$ extension of the standard model (SM), where the global $B-L$ (baryon number minus lepton number) symmetry in the SM is gauged, and three generations of right-handed neutrinos and a $B-L$ Higgs field are introduced. Associated with the $B-L$ gauge symmetry breaking by a VEV of the $B-L$ Higgs field, the seesaw mechanism for generating the neutrino mass is automatically implemented after the electroweak symmetry breaking in the SM. In this model context, we introduce a $Z_2$-parity and assign an odd parity for one right-handed neutrino while even parities for the other fields. Therefore, the dark matter candidate is identified as the right-handed Majorana neutrino with odd $Z_2$ parity, keeping the minimality of the particle content intact. When the dark matter particle communicates with the SM particles mainly through the $B-L$ gauge boson ($Z_{BL}^{\prime }$ boson), its relic abundance is determined by only three free parameters, the $B-L$ gauge coupling (${\alpha }_{BL}$), the $Z_{BL}^{\prime }$ boson mass ($m_{Z^{\prime }}$) and the dark matter mass ($m_{\mathrm{DM}}$). With the cosmological upper bound on the dark matter relic abundance we find a lower bound on ${\alpha }_{BL}$ as a function of $m_{Z^{\prime }}$. On the other hand, we interpret the recent LHC Run-2 results on search for $Z^{\prime }$ boson resonance to an upper bound on ${\alpha }_{BL}$ as a function of $m_{Z^{\prime }}$. Combining the two results we identify an allowed parameter region for this “$Z_{BL}^{\prime }$ portal” dark matter scenario, which turns out to be a narrow window with the lower mass bound of $m_{Z^{\prime }}>2.5\mathrm{TeV}$.