Following Krotov and Polyakov [Nucl. Phys. B849, 410 (2011)], we show that in global de Sitter space its isometry is broken by the loop IR divergences for any invariant vacuum state of the massive scalars. We derive a kinetic equation in global de Sitter space that follows from the Dyson-Schwinger equation of the Schwinger-Keldysh diagrammatic technique in the IR limit and allows us to understand the physical meaning and consequences of the loop IR divergences. In many respects, the isometry breaking in global de Sitter space is similar to the one in the contracting Poincaré patch of de Sitter space. Hence, as a warm-up exercise we study the kinetic equation and properties of its solutions in the expanding and contracting Poincaré patches of de Sitter space. Quite unexpectedly, we find that under some initial conditions there is an explosive production of massive particles in the expanding Poincaré patch.

We propose a new holonomy formulation for spin foams, which naturally extends the theory space of lattice gauge theories. This allows current spin foam models to be defined on arbitrary 2-complexes as well as to generalize current spin foam models to arbitrary, in particular, finite groups. The similarity with standard lattice gauge theories allows us to apply standard coarse graining methods, which for finite groups can now be easily considered numerically. We will summarize other holonomy and spin network formulations of spin foams and group field theories and explain how the different representations arise through variable transformations in the partition function. A companion paper will provide a description of boundary Hilbert spaces as well as a canonical dynamic encoded in transfer operators.

We propose a Lorentz invariant version of Tseytlin’s doubled world-sheet theory that makes T-duality covariance of the string manifest. This theory can be derived as a gauge fixed version of Buscher’s gauging procedure, in which the leftover gauge field component acts as a Lagrange multiplier. This description can naturally account for fractional linear $O(D,D)$ transformations of the metric and $b$ field. It is capable of describing nongeometric backgrounds; geometric and nongeometric fluxes are encoded in the doubled antisymmetric tensor field strength.

We show that nearly extremal Kerr black holes have two distinct sets of quasinormal modes, which we call zero-damping modes (ZDMs) and damped modes (DMs). The ZDMs exist for all harmonic indices $l$ and $m\ge 0$, and their frequencies cluster onto the real axis in the extremal limit. The DMs have nonzero damping for all black hole spins; they exist for all counterrotating modes ($m<0$) and for corotating modes with $0\le \mu \lesssim {\mu }_c=0.74$ (in the eikonal limit), where $\mu \equiv m/(l+1/2)$. When the two families coexist, ZDMs and DMs merge to form a single set of quasinormal modes as the black hole spin decreases. Using the effective potential for perturbations of the Kerr spacetime, we give intuitive explanations for the absence of DMs in certain areas of the spectrum and for the branching of the spectrum into ZDMs and DMs at large spins.

We propose an interpretation of the two neutrino initiated cascade events with PeV energies observed by IceCube: Ultrahigh energy cosmic ray protons (or Fe nuclei) scatter on cosmic microwave background photons through the Delta-resonance (the Berezinsky-Zatsepin process) yielding charged pions and neutrons. The neutron decays give electron-antineutrinos which undergo neutrino oscillations to populate all antineutrino flavors, but the electron-antineutrino flux remains dominant. At 6.3 PeV electron-antineutrino energy their annihilation on electrons in the IceCube detector is enhanced by the Glashow resonance (the $W$-boson) whose decays can give the PeV showers observed in the IceCube detector. The two observed showers with $\sim 1\mathrm{PeV}$ energies would need to be from $W$ leptonic decays to electrons and taus. An order of magnitude higher event rate of showers at 6.3 PeV is predicted from $W$ to hadron decays. This interpretation can be tested in the near term. It has significant physics implications on the origin of the highest energy cosmic rays, since neutrino events and cosmic ray events likely share a common origin.

A recent global fit to the constrained minimal supersymmetric extension of the Standard Model incorporating current constraints on supersymmetry, including missing transverse energy searches at the LHC, BR($B_s\to {\mu }^{+}{\mu }^{-}$) and the direct XENON100 search for dark matter, favors points towards the end of the stau-neutralino (${\tilde{\tau }}_1\mathrm{\text{−}}\chi$) coannihilation strip with relatively large $m_{1/2}$ and $10\lesssim \tan \beta \lesssim 40$ and points in the $H/A$ rapid-annihilation funnel with $\tan \beta \sim 50$. The coannihilation points typically have $m_{{\tilde{\tau }}_1}-m_{\chi }\lesssim 5\mathrm{GeV}$, and a significant fraction, including the most-favored point, has $m_{{\tilde{\tau }}_1}-m_{\chi }<m_{\tau }$. In such a case, the ${\tilde{\tau }}_1$ lifetime would be so long that the ${\tilde{\tau }}_1$ would be detectable as a long-lived massive charged particle that may decay inside or outside the apparatus. We show that CMSSM scenarios close to the tip of the coannihilation strip for $\tan \beta \lesssim 40$ are already excluded by LHC searches for massive charged particles and discuss the prospects for their detection in the CMS and ATLAS detectors via time-of-flight measurements, anomalous heavy ionization or decays into one or more soft charged particles.

Vector boson fusion processes offer a promising avenue to study the noncolored sectors of supersymmetric extensions of the Standard Model at the LHC. A feasibility study for searching for the chargino/neutralino system in the $R$-parity conserving minimal supersymmetric Standard Model is presented. The high $E_{\mathrm{T}}$ forward jets in opposite hemispheres are used to trigger vector boson fusion events, so that the production of the lightest chargino ${\tilde{\chi }}_1^{\pm }$ and the second-lightest neutralino ${\tilde{\chi }}_2^0$ can be probed without a bias by experimental triggers. Kinematic requirements are developed to search for signals of these supersymmetric states above Standard Model backgrounds in both $\tau$ and light lepton ($e$ and $\mu$) final states at $\sqrt{s}=8\mathrm{TeV}$.

We consider a three Higgs doublet model with an $S_3$ symmetry in which beside the standard model-like doublet, there are two fermiophobic doublets. Due to the new charged scalars, there is an enhancement in the two-photon decay, while the other channels have the same decay widths as the standard model neutral Higgs. The fermiophobic scalars are mass degenerated unless soft terms breaking the $S_3$ symmetry are added.

The intrinsic flux of very high-energy (VHE, energy $\gtrsim 100\mathrm{GeV}$) $\gamma$ rays from extragalactic sources is attenuated due to pair production in the interaction with photons of the extragalactic background light (EBL). Depending on the distance of the source, the Universe should be opaque to VHE photons above a certain energy. However, indications exist that the Universe is more transparent than previously thought. A recent statistical analysis of a large sample of VHE spectra shows that the correction for absorption with current EBL models is too strong for the data points with the highest attenuation. An explanation might be the oscillation of VHE photons into hypothetical axionlike particles (ALPs) in ambient magnetic fields. This mechanism would decrease the opacity, as ALPs propagate unimpeded over cosmological distances. Here, a large sample of VHE $\gamma$-ray spectra obtained with imaging air Cherenkov telescopes is used to set, for the first time, lower limits on the photon-ALP coupling constant $g_{a\gamma }$ over a large range of ALP masses. The conversion in different magnetic field configurations, including intra-cluster and intergalactic magnetic fields together with the magnetic field of the Milky Way, is investigated, taking into account the energy dependence of the oscillations. For optimistic scenarios of the intervening magnetic fields, a lower limit on $g_{a\gamma }$ of the order of ${10}^{-12}{\mathrm{GeV}}^{-1}$ is obtained, whereas more conservative model assumptions result in $g_{a\gamma }\gtrsim 2\times {10}^{-11}{\mathrm{GeV}}^{-1}$. The latter value is within reach of future dedicated ALP searches.

We study the Sivers single spin asymmetry of the Drell-Yan lepton pair production in the small-$x$ regime. We find that in the corresponding kinematic region the spin asymmetry calculated in the small-$x$ approach is consistent with either the usual transverse-momentum-dependent factorization formalism or the collinear factorization formalism, respectively. We estimate the Sivers asymmetry for both polarized $\mathrm{p}+\mathrm{p}$ and $\mathrm{p}+\mathrm{A}$ collisions and argue that the Drell-Yan production is an interesting and unique probe for both the transverse spin physics and the small-$x$ saturation effect.

The transverse momentum dependent helicity distributions of valence quarks are calculated in the light-cone diquark model by adopting two different approaches. We use the model results to analyze the $P_{h\perp }$-dependent double spin asymmetries for ${\pi }^{+}$, ${\pi }^{-}$, and ${\pi }^0$ productions in semi-inclusive deep inelastic scattering, and find that the asymmetries agree with the CLAS data in one of the approaches. By taking the Fourier transform of the transverse momentum dependent helicity distributions, we obtain the helicity distributions of valence quarks in the transverse coordinate space, and then apply them further to predict the Bessel-weighted double spin asymmetries of ${\pi }^{+}$, ${\pi }^{-}$, and ${\pi }^0$ productions in semi-inclusive deep inelastic scattering at CLAS, COMPASS, and HERMES for the first time. The shape of the Bessel-weighted double spin asymmetry thereby provides a direct probe on the transverse structure of longitudinally polarized quarks.

Most of the models of jet quenching generally assumes that a jet always travels in a straight eikonal path, which is indeed true for sufficiently hard jet but may not be a good one for moderate and low momentum jet. In this article an attempt has been made to relax part of this approximation for $2\to 3$ processes and found a (15–20)% suppression in the differential cross section for moderately hard jets because of the noneikonal effects. In particular, for the process $q{q}^{\prime }\to q{q}^{\prime }g$ in the centre of momentum frame the scattering with an angle wider than $\pm 0.52\pi$ is literally forbidden unlike the process $gg\to ggg$ that allows an angular range $\pm \pi$. This may have consequence on the suppression of hadronic spectra at low transverse momenta.

We focus on the problem of disentangling the single (SPS) and double (DPS) parton scattering modes in the production of $J/\psi$ pairs at the LHC conditions. Our analysis is based on comparing the shapes of the differential cross sections and on studying their behavior under imposing kinematical cuts. On the SPS side, we consider the leading-order $\mathcal{O}({\alpha }_s^4)$ contribution with radiative corrections (taken into account in the framework of the $k_t$-factorization approach) and the subleading $\mathcal{O}({\alpha }_s^6)$ contribution from pseudodiffractive gluon-gluon scattering represented by one-gluon exchange and two-gluon exchange mechanisms. We come to the conclusion that disentangling the SPS and DPS modes is rather difficult on the basis of azimuthal correlations, while the rapidity difference looks more promising, provided the acceptance of the experimental detectors has enough rapidity coverage.

We investigate the effects of the littlest Higgs model with $T$ parity up to the QCD next-to-leading order (NLO) on the $W_H^{\pm }{Z}_H$ productions at the CERN Large Hadron Collider (LHC), and discuss the kinematic distributions of final decay products and the theoretical dependence of the cross section on the factorization/renormalization scale. We find that the QCD NLO corrections reduce the scale uncertainty of the leading-order cross section in the case of ${\mu }_F={\mu }_R$. By adopting the prospino subtraction scheme [scheme (II)] in analysing the QCD NLO contributions, we obtain the numerical results which keep the convergence of the perturbative QCD description. Our results by adopting scheme (II) at the 14 TeV (8 TeV) LHC show that the $K$-factor for the $W_H^{+}{Z}_H$ production varies in the range of 1.01–1.10 (1.00–1.08), while the $K$-factor for the $W_H^{-}{Z}_H$ production varies in the range of 1.11–1.13 (1.11–1.12), when the global symmetry-breaking scale $f$ goes from 400 GeV to 1.5 TeV (1 TeV).

We study the electromagnetic Bethe-Heitler type contribution to neutrino-induced deeply virtual meson production ($\nu \mathrm{DVMP}$). Such $\mathcal{O}({\alpha }_{\mathrm{em}})$ corrections decrease with $Q^2$ in the Bjorken regime less steeply than the standard $\nu \mathrm{DVMP}$ handbag contribution. Therefore, they are relatively enhanced at high $Q^2$. The Bethe-Heitler terms give rise to an angular correlation between the lepton and hadron scattering planes with harmonics sensitive to the real and imaginary parts of the $\nu \mathrm{DVMP}$ amplitude. These corrections constitute a few percent effect in the kinematics of the forthcoming Minerva experiment at Fermilab and should be taken into account in precision tests of generalized parton distributions parametrizations. For virtualities $Q^2\sim 100{\mathrm{GeV}}^2$ these corrections become on a par with $\nu \mathrm{DVMP}$ handbag contributions. A computational code, which can be used for the evaluation of these corrections employing various generalized parton distributions models, is provided in the Supplemental Material.

A $2.25\times {10}^8$ $J/\psi$ event sample accumulated with the BESIII detector is used to study the doubly Okubo-Zweig-Iizuka-suppressed decay modes $J/\psi \to \gamma \omega \varphi$, $\omega \to {\pi }^{+}{\pi }^{-}{\pi }^0$, $\varphi \to K^{+}{K}^{-}$. A strong deviation ($>30\sigma$) from three-body $J/\psi \to \gamma \omega \varphi$ phase space is observed near the $\omega \varphi$ mass threshold that is consistent with a previous observation reported by the BESII experiment. A partial wave analysis with a tensor covariant amplitude that assumes that the enhancement is due to the presence of a resonance, the $X(1810)$, is performed and confirms that the spin-parity of the $X(1810)$ is $0^{++}$. The mass and width of the $X(1810)$ are determined to be $M=1795\pm 7(\mathrm{stat}{)}_{-5}^{+13}(\mathrm{syst})\pm 19(\mathrm{mod})\mathrm{MeV}/c^2$ and $\Gamma =95\pm 10(\mathrm{stat}{)}_{-34}^{+21}(\mathrm{syst})\pm 75(\mathrm{mod})\mathrm{MeV}/c^2$, respectively, and the product branching fraction is measured to be $\mathcal{B}(J/\psi \to \gamma X(1810))\times \mathcal{B}(X(1810)\to \omega \varphi )=(2.00\pm 0.08(\mathrm{stat}{)}_{-1.00}^{+0.45}(\mathrm{syst})\pm 1.30(\mathrm{mod}))\times {10}^{-4}$. These results are consistent within errors with those of the BESII experiment.

In this paper the arising of Gribov copies both in Landau and Coulomb gauges in regions with nontrivial topologies but flat metric, (such as closed tubes $S^1\times D^2$, or $\mathbb{R}\times T^2$) will be analyzed. Using a novel generalization of the hedgehog ansatz beyond spherical symmetry, analytic examples of Gribov copies of the vacuum will be constructed. Using such ansatz, we will also construct the elliptic Gribov pendulum. The requirement of absence of Gribov copies of the vacuum satisfying the strong boundary conditions implies geometrical constraints on the shapes and sizes of the regions with nontrivial topologies.

By using superfield techniques, the effective potential of the $\mathcal{N}=1$ Wess-Zumino model in $2+1$ dimensions is computed off-shell up to two loops. It is shown that supersymmetry is not dynamically broken and that dynamical generation of mass does not occur perturbatively. We also investigate the renormalization of the effective potential and determine the renormalization group gamma and beta functions, showing that this model is infrared-free. Comparison with some other results in the literature is provided.

We present an analysis of the dynamics of the equifacial pentahedron on the Kapovich-Millson phase space under a volume preserving Hamiltonian. The classical dynamics of polyhedra under such a Hamiltonian may arise from the classical limit of the node volume operators in loop quantum gravity. The pentahedron is the simplest nontrivial polyhedron for which the dynamics may be chaotic. We consider the distribution of polyhedral configurations throughout the space and find indications that the borders between certain configurations act as separatrices. We examine the local stability of trajectories within this phase space and find that locally unstable regions dominate although extended stable regions are present. Canonical and microcanonical estimates of the Kolmogorov-Sinai entropy suggest that the pentahedron is a strongly chaotic system. The presence of chaos is further suggested by calculations of intermediate time Lyapunov exponents which saturate to nonzero values.