We investigate the behavior of small subsets of causal sets that approximate Minkowski space in three, four, and five dimensions, and show that their effective dimension decreases smoothly at small distances. The details of the short distance behavior depend on a choice of dimensional estimator, but for a reasonable version of the Myrheim-Meyer dimension, the minimum dimension is $d\approx 2$, reproducing results that have been seen in other approaches to quantum gravity.

We construct analytical Lifshitz massive black brane solutions in massive Einstein-Maxwell-dilaton gravity theory. We also study the thermodynamics of these black brane solutions and obtain the thermodynamical stability conditions. On the dual nonrelativistic boundary field theory with Lifshitz symmetry, we analytically compute the DC transport coefficients, including the electric conductivity, thermoelectric conductivity, and thermal conductivity. The novel property of our model is that the massive term supports the Lifshitz black brane solutions with $z\ne 1$ in such a way that the DC transport coefficients in the dual field theory are finite. We also find that the Wiedemann-Franz law in this dual boundary field theory is violated, which indicates that it may involve strong interactions.

Dark matter in the halos surrounding galaxy groups and clusters can annihilate to high-energy photons. Recent advancements in the construction of galaxy group catalogs provide many thousands of potential extragalactic targets for dark matter. In this paper, we outline a procedure to infer the dark matter signal associated with a given galaxy group. Applying this procedure to a catalog of sources, one can create a full-sky map of the brightest extragalactic dark matter targets in the nearby Universe ($z\lesssim 0.03$), supplementing sources of dark matter annihilation from within the local group. As with searches for dark matter in dwarf galaxies, these extragalactic targets can be stacked together to enhance the signals associated with dark matter. We validate this procedure on mock Fermi gamma-ray data sets using a galaxy catalog constructed from the DarkSky $N$-body cosmological simulation and demonstrate that the limits are robust, at $\mathcal{O}(1)$ levels, to systematic uncertainties on halo mass and concentration. We also quantify other sources of systematic uncertainty arising from the analysis and modeling assumptions. Our results suggest that a stacking analysis using galaxy group catalogs provides a powerful opportunity to discover extragalactic dark matter and complements existing studies of Milky Way dwarf galaxies.

We present results of a lattice QCD calculation of $B\to D^{*}$ and $B_s\to D_s^{*}$ axial vector matrix elements with both states at rest. These zero recoil matrix elements provide the normalization necessary to infer a value for the CKM matrix element $|V_{cb}|$ from experimental measurements of ${\overline{B}}^0\to D^{*+}{\ell }^{-}\overline{\nu }$ and ${\overline{B}}_s^0\to D_s^{*+}{\ell }^{-}\overline{\nu }$ decay. Results are derived from correlation functions computed with highly improved staggered quarks (HISQ) for light, strange, and charm quark propagators, and nonrelativistic QCD for the bottom quark propagator. The calculation of correlation functions employs MILC Collaboration ensembles over a range of three lattice spacings. These gauge field configurations include sea quark effects of charm, strange, and equal-mass up and down quarks. We use ensembles with physically light up and down quarks, as well as heavier values. Our main results are ${\mathcal{F}}^{B\to D^{*}}(1)=0.895\pm 0.010_{\mathrm{stat}}\pm {0.024}_{\mathrm{sys}}$ and ${\mathcal{F}}^{B_s\to D_s^{*}}(1)=0.883\pm 0.012_{\mathrm{stat}}\pm 0.028_{\mathrm{sys}}$. We discuss the consequences for $|V_{cb}|$ in light of recent investigations into the extrapolation of experimental data to zero recoil.

We present nonperturbative first-principle results for quark, gluon, and meson 1PI correlation functions of two-flavor Landau-gauge QCD in the vacuum. These correlation functions carry the full information about the theory. They are obtained by solving their functional renormalization group equations in a systematic vertex expansion, aiming at apparent convergence. This work represents a crucial prerequisite for quantitative first-principle studies of the QCD phase diagram and the hadron spectrum within this framework. In particular, we have computed the gluon, ghost, quark, and scalar-pseudoscalar meson propagators, as well as gluon, ghost-gluon, quark-gluon, quark, quark-meson, and meson interactions. Our results stress the crucial importance of the quantitatively correct running of different vertices in the semiperturbative regime for describing the phenomena and scales of confinement and spontaneous chiral symmetry breaking without phenomenological input.

Muonium is a purely leptonic system, but the accuracy of the theoretical QED prediction for its hyperfine interval is limited in part by hadronic effects. Here we consider radiative corrections to the leading hadronic vacuum polarization term, since their size is larger than the uncertainty in the calculation of the leading hadronic term itself. The total hadronic contribution of relative order of $\alpha$ in comparison with the leading hadronic term is found to be 4.97(19) Hz. The hadronic uncertainty sets an “ultimate” limit on the use of the $1s$ hyperfine interval in muonium as a QED variable.

Using the entire Belle data sample of $980{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ collisions, we present the results of a study of excited ${\mathrm{\Omega }}_c$ charmed baryons in the decay mode ${\mathrm{\Xi }}_c^{+}{K}^{-}$. We show confirmation of four of the five narrow states reported by the LHCb Collaboration: the ${\mathrm{\Omega }}_c(3000)$, ${\mathrm{\Omega }}_c(3050)$, ${\mathrm{\Omega }}_c(3066)$, and ${\mathrm{\Omega }}_c(3090)$.

We reply to Mazzitelli and Trombetta’s comment [1] on our cosmological constant paper [2].

In a recent paper [Q. Wang, Z. Zhu, and W. G. Unruh, Phys. Rev. D 95, 103504 (2017)] it was argued that, due to the fluctuations around its mean value, vacuum energy gravitates differently from what was previously assumed. As a consequence, the Universe would accelerate with a small Hubble expansion rate, solving the cosmological constant and dark energy problems. We point out here that the results depend on the type of cutoff used to evaluate the vacuum energy. In particular, they are not valid when one uses a covariant cutoff such that the zero-point energy density is positive definite.

The analogy between black hole radiation and accelerating mirror radiation (the dynamical Casimir effect) is particularly strong for mirror trajectories giving rise to a constant thermal flux of particles. We present new ways to achieve such thermal plateaus, and customize their finite, semi-infinite, and eternal presence, corresponding to forming/collapsing, complete-evaporation/remnants, and eternal black holes. We find simple expressions for the energy flux in terms of the mirror rapidity as a function of proper time and null time.

We study critical phenomena in the collapse of rotating ultrarelativistic perfect fluids, in which the pressure $P$ is related to the total energy density $\rho$ by $P=\kappa \rho$, where $\kappa$ is a constant. We generalize earlier results for radiation fluids with $\kappa =1/3$ to other values of $\kappa$, focusing on $\kappa <1/9$. For $1/9<\kappa \lesssim 0.49$, the critical solution has only one unstable, growing mode, which is spherically symmetric. For supercritical data it controls the black-hole mass, while for subcritical data it controls the maximum density. For $\kappa <1/9$, an additional axial $l=1$ mode becomes unstable. This controls either the black-hole angular momentum, or the maximum angular velocity. In theory, the additional unstable $l=1$ mode changes the nature of the black-hole threshold completely: at sufficiently large initial rotation rates $\mathrm{\Omega }$ and sufficient fine-tuning of the initial data to the black-hole threshold we expect to observe nontrivial universal scaling functions (familiar from critical phase transitions in thermodynamics) governing the black-hole mass and angular momentum, and, with further fine-tuning, eventually a finite black-hole mass almost everywhere on the threshold. In practice, however, the second unstable mode grows so slowly that we do not observe this breakdown of scaling at the level of fine-tuning we can achieve, nor systematic deviations from the leading-order power-law scalings of the black-hole mass. We do see systematic effects in the black-hole angular momentum, but it is not clear yet if these are due to the predicted nontrivial scaling functions, or to nonlinear effects at sufficiently large initial angular momentum (which we do not account for in our theoretical model).

If dark energy (DE) is a dynamical field rather than a cosmological constant, an interaction between DE and the neutrino sector could exist, modifying the neutrino oscillation phenomenology and causing $CP$ and apparent Lorentz violating effects. The terms in the Hamiltonian for flavor propagation induced by the DE-neutrino coupling do not depend on the neutrino energy, while the ordinary components decrease as $\mathrm{\Delta }{m}^2/E_{\nu }$. Therefore, the DE-induced effects are absent at lower neutrino energies, but become significant at higher energies, allowing to be searched for by neutrino observatories. We explore the impact of the DE-neutrino coupling on the oscillation probability and the flavor transition in the three-flavor framework, and investigate the $CP$-violating and apparent Lorentz violating effects. We find that DE-induced effects become observable for $E_{\nu }{m}_{\mathrm{eff}}\sim {10}^{-20}{\mathrm{GeV}}^2$, where $m_{\mathrm{eff}}$ is the effective mass parameter in the DE-induced oscillation probability, and $CP$ is violated over a wide energy range. We also show that current and future experiments have the sensitivity to detect anomalous effects induced by a DE-neutrino coupling and probe the new mixing parameters. The DE-induced effects on neutrino oscillation can be distinguished from other new physics possibilities with similar effects, through the detection of the directional dependence of the interaction, which is specific to this interaction with DE. However, current experiments will not yet be able to measure the small changes of $\sim 0.03\%$ in the flavor composition due to this directional effect.

The holographic distribution amplitudes (DAs) for the $K$ pseudoscalar meson are derived. For this aim, the light-front wave function (LFWF) of the $K$ meson is extracted within the framework of the anti–de Sitter/quantum chromodynamics (AdS/QCD) correspondence. We consider a momentum-dependent (dynamical) helicity wave function that contains the dynamical spin effects. We use the LFWF to predict the radius and the electromagnetic form factor of the kaon and compare them with the experimental values. Then, the holographic twist-2 DA of $K$ meson ${\varphi }_K(\alpha ,\mu )$ is investigated and compared with the result of the light-cone sum rules (LCSR). The transition form factors of the semileptonic $B\to K{\ell }^{+}{\ell }^{-}$ decays are derived from the holographic DAs of the kaon. With the help of these form factors, the differential branching ratio of the $B\to K{\mu }^{+}{\mu }^{-}$ on $q^2$ is plotted. A comparison is made between our prediction in AdS/QCD and the results obtained from two models including the LCSR and the lattice QCD as well as the experimental values.

We present a scenario for nonthermal production of dark matter from evaporation of primordial black holes. A period of very early matter domination leads to formation of black holes with a maximum mass of $\simeq 2\times {10}^8\mathrm{g}$, whose subsequent evaporation prior to big bang nucleosynthesis can produce all of the dark matter in the Universe. We show that the correct relic abundance can be obtained in this way for thermally underproduced dark matter in the 100 GeV–10 TeV mass range. To achieve this, the scalar power spectrum at small scales relevant for black hole formation should be enhanced by a factor of $\mathcal{O}({10}^5)$ relative to the scales accessible by the cosmic microwave background experiments.

We present double-differential measurements of antineutrino charged-current quasielastic scattering in the MINERvA detector. This study improves on a previous single-differential measurement by using updated reconstruction algorithms and interaction models and provides a complete description of observed muon kinematics in the form of a double-differential cross section with respect to muon transverse and longitudinal momentum. We include in our signal definition zero-meson final states arising from multinucleon interactions and from resonant pion production followed by pion absorption in the primary nucleus. We find that model agreement is considerably improved by a model tuned to MINERvA inclusive neutrino scattering data that incorporates nuclear effects such as weak nuclear screening and two-particle, two-hole enhancements.

This paper studies the complexity between states in quantum field theory by introducing a Finsler structure based on ladder operators (the generalization of creation and annihilation operators). Two simple models are shown as examples to clarify the differences between complexity and other conceptions such as complexity of formation and entanglement entropy. When it is applied into thermofield double (TFD) states in $d$-dimensional conformal field theory, results show that the complexity density between them and corresponding vacuum states are finite and proportional to $T^{d-1}$, where $T$ is the temperature of TFD state. Especially, a proof is given to show that fidelity susceptibility of a TFD state is equivalent to the complexity between it and corresponding vacuum state, which gives an explanation why they may share the same object in holographic duality. Some enlightenments to holographic conjectures of complexity are also discussed.

The $D=11$ pure spinor formulation of the superparticle allows a simple realization of covariant quantization, unlike the $D=11$ Brink-Schwarz-like superparticle. We explicitly show the equivalence between the cohomologies of these two models in the context of two different group decompositions: $SO(10,1)\to SO(1,1)\times SO(9)$ and $SO(10,1)\to SO(3,1)\times SO(7)$. We also carry out a light-cone analysis of the pure spinor cohomology and show that it correctly reproduces the $SO(9)$ equations of motion for $D=11$ linearized supergravity.

We consider the exact $R$-matrix of ${\mathrm{AdS}}_3/{\mathrm{CFT}}_2$, which is the building block for describing the scattering of worldsheet excitations of the light-cone gauge-fixed backgrounds ${\mathrm{AdS}}_3\times S^3\times T^4$ and ${\mathrm{AdS}}_3\times S^3\times S^3\times S^1$ with pure Ramond-Ramond fluxes. We show that $R$ is invariant under a “deformed boost” symmetry, for which we write an explicit exact coproduct, i.e. its action on two-particle states. When we include the boost, the symmetries of the $R$-matrix close into a $q$-Poincaré superalgebra. Our findings suggest that the recently discovered boost invariance in ${\mathrm{AdS}}_5/{\mathrm{CFT}}_4$ may be a common feature of AdS/CFT systems that are treatable with the exact techniques of integrability. With the aim of going towards a universal formulation of the underlying Hopf algebra, we also propose a universal form of the ${\mathrm{AdS}}_3/{\mathrm{CFT}}_2$ classical $r$-matrix.

In this paper, we discuss the noncommutative ${\mathrm{QED}}_2$ in the $S$-matrix framework. We are interested in perturbatively proving that the exact Schwinger mass ${\mu }^2=\frac{e^2}{\pi }$ does not receive noncommutative corrections to any order in loop expansion. In this sense, the $S$-matrix approach is useful since it allows us to work with the effective action $\mathrm{\Gamma }[A]$ (interaction term) to compute the corresponding gauge field 1PI two-point function at higher orders. Furthermore, by means of ${\alpha }^{*}$-cohomology, we generalize the ${\mathrm{QED}}_2$ $S$-matrix analysis in the Moyal star product to all translation-invariant star products.