The bulk viscosity, $\zeta$ and its ratio with the shear viscosity, $\zeta /\eta$ have been studied in an anisotropically expanding pure glue plasma in the presence of turbulent color fields. It has been shown that the anisotropy in the momentum distribution function of gluons, which has been determined from a linearized transport equation eventually leads to the bulk viscosity. For the isotropic (equilibrium) state, a recently proposed quasiparticle model of pure $SU(3)$ lattice QCD equation of state has been employed where the interactions are encoded in the effective fugacity. It has been argued that the interactions present in the equation of state, significantly contribute to the bulk viscosity. Its ratio with the shear viscosity is significant even at $1.5T_c$. Thus, one needs to take in account the effects of the bulk viscosity while studying the hydrodynamic expansion of quark-gluon plasma in the Relativistic Heavy Ion Collider and the Large Hadron Collider.

We formulate an effective theory for systems containing a heavy Majorana fermion, such as bound states of a long-lived gluino. This “Majorana HQET” has the same degrees of freedom as the well-studied Dirac HQET. It respects an emergent $\mathrm{U}(1)$ symmetry despite the fundamental absence of a $\mathrm{U}(1)$ for Majorana fermions. Reparametrization invariance works identically in the two HQETs. Remarkably, while a Dirac HQET may or may not be charge conjugation symmetric, a charge conjugation symmetry emerges in all Majorana HQETs, potentially offering low energy probes to distinguish the two theories.

We present an update of our analysis of short-baseline neutrino oscillation data in the framework of $3+1$ neutrino mixing taking into account the recent update of MiniBooNE antineutrino data and the recent results of the MINOS search for ${\nu }_{\mu }$ disappearance into sterile neutrinos (the more complicated $3+2$ neutrino mixing is not needed since the $CP$-violating difference between MiniBooNE neutrino and antineutrino data has diminished). The results of our fits of short-baseline neutrino oscillation data including the MiniBooNE low-energy anomaly (now present both in the neutrino and antineutrino data) lead to a strong tension between appearance and disappearance data. Hence, it seems likely that the low-energy anomaly is not due to ${\stackrel{(-)}{\nu }}_{\mu }\to {\stackrel{(-)}{\nu }}_e$ transitions. Excluding the MiniBooNE low-energy anomaly, appearance and disappearance data are marginally compatible. The global analysis has the best-fit point at $\Delta m_{41}^2\approx 5.6{\mathrm{eV}}^2$, which is rather large in comparison with cosmological bounds, but there are three regions within $1\sigma$ at $\Delta m_{41}^2\approx 1.6$, 1.2, $0.91{\mathrm{eV}}^2$. We also show that the data on the Gallium neutrino anomaly favor values of $\Delta m_{41}^2$ larger than about $1{\mathrm{eV}}^2$.

Using $106\times {10}^6$ ${\psi }^{\prime }$ events collected with the BESIII detector at the BEPCII storage ring, the higher-order multipole amplitudes in the radiative transition ${\psi }^{\prime }\to \gamma {\chi }_{c2}\to \gamma {\pi }^{+}{\pi }^{-}/\gamma K^{+}{K}^{-}$ are measured. A fit to the ${\chi }_{c2}$ production and decay angular distributions yields $\mathrm{M}2=0.046\pm 0.010\pm 0.013$ and $\mathrm{E}3=0.015\pm 0.008\pm 0.018$, where the first errors are statistical and the second systematic. Here M2 denotes the normalized magnetic quadrupole amplitude and E3 the normalized electric octupole amplitude. This measurement shows evidence for the existence of the M2 signal with $4.4\sigma$ statistical significance and is consistent with the charm quark having no anomalous magnetic moment.

We consider a topologically twisted maximally supersymmetric Yang-Mills theory on a four-manifold of the form $V=W\times {\mathbb{R}}_{+}$. ’t Hooft disorder operators localized in the boundary component at finite distance of $V$ are relevant for the study of knot theory on the three-manifold $W$ and have recently been constructed for a gauge group of rank one. We extend this construction to an arbitrary gauge group $G$. For certain values of the magnetic charge of the ’t Hooft operator, the solutions are obtained by embedding the rank-one solutions in $G$ and can be given in closed form.

The proximity force approximation (PFA) has been widely used as a tool to evaluate the Casimir force between smooth objects at small distances. In spite of being intuitively easy to grasp, it is generally believed to be an uncontrolled approximation. Indeed, its validity has only been tested in particular examples, by confronting its predictions with the next-to-leading-order (NTLO) correction extracted from numerical or analytical solutions obtained without using the PFA. In this article we show that the PFA and its NTLO correction may be derived within a single framework, as the first two terms in a derivative expansion. To that effect, we consider the Casimir energy for a vacuum scalar field with Dirichlet conditions on a smooth curved surface described by a function $\psi$ in front of a plane. By regarding the Casimir energy as a functional of $\psi$, we show that the PFA is the leading term in a derivative expansion of this functional. We also obtain the general form of the corresponding NTLO correction, which involves two derivatives of $\psi$. We show, by evaluating this correction term for particular geometries, that it properly reproduces the known corrections to PFA obtained from exact evaluations of the energy.

Several extensions of the standard model and, in particular, superstring theories suggest the existence of axionlike particles (ALPs), which are very light spin-zero bosons with a two-photon coupling. As a consequence, photon-ALP oscillations occur in the presence of an external magnetic field, and ALPs can lead to observable effects on the measured photon spectrum of astrophysical sources. An intriguing situation arises when blazars are observed in the very-high-energy (VHE) band—namely, above 100 GeV—as it is the case with the presently operating Imaging Atmospheric Cherenkov Telescopes H.E.S.S, Major Atmospheric Gamma Imaging Cherenkov telescope, Collaboration of Australia and Nippon for a Gamma Ray Observatory in the Outback III, and VERITAS. The extragalactic background light produced by galaxies during cosmic evolution gives rise to a source dimming which becomes important in the VHE band and increases with energy, since hard photons from a blazar scatter off soft extragalactic background light photons thereby disappearing into $e^{+}{e}^{-}$ pairs. This dimming can be considerably reduced by photon-ALP oscillations, and since they are energy independent the resulting blazar spectra become harder than expected. We consider throughout a scenario first proposed by De Angelis, Roncadelli, and Mansutti in which the above strategy is implemented with photon-ALP oscillations triggered by large-scale magnetic fields, and we systematically investigate its implications for VHE blazars. We find that for ALPs lighter than $5·{10}^{-10}\mathrm{eV}$ the photon survival probability is larger than predicted by conventional physics above a few hundred GeV. Specifically, a boost factor of 10 can easily occur for sources at large distance and large energy, e.g. at 8 TeV for the blazar 1ES 0347-121 at redshift $z=0.188$. This is a clear-cut prediction which can be tested with the planned Cherenkov Telescope Array and the High Altitude Water Cherenkov Experiment (HAWC) water Cherenkov $\gamma$-ray observatory and possibly with the currently operating Imaging Atmospheric Cherenkov Telescopes as well as with detectors like Astrophysical Radiation with Ground-based Observatory at YangBaJing and Multiple Institution Los Alamos Gamma Ray Observatory. Moreover, we show that the De Angelis, Roncadelli, and Mansutti scenario offers a new interpretation of the VHE blazars detected so far, according to which the large spread in the values of the observed spectral index is mainly due to the wide spread in the source distances rather than to large variations of their internal physical properties. Finally, we stress that ALPs with the right properties to produce the above effects can be discovered by the Gamma-meV experiment at FERMILAB and more likely with the planned photon regeneration experiment ALPS at Deutsches Elektronen Synchrotron.

We perform the Hamiltonian analysis for the lowest-order effective action, up to second order in derivatives, of the complete Hořava theory. The model includes the invariant terms that depend on ${\partial }_i\ln N$ proposed by Blas, Pujolàs, and Sibiryakov. We show that the algebra of constraints closes. The Hamiltonian constraint is of second-class behavior and it can be regarded as an elliptic partial differential equation for $N$. The linearized version of this equation is a Poisson equation for $N$ that can be solved consistently. The preservation in time of the Hamiltonian constraint yields an equation that can be consistently solved for a Lagrange multiplier of the theory. The model has six propagating degrees of freedom in the phase space, corresponding to three even physical modes. When compared with the $\lambda R$ model studied by us in a previous paper, it lacks two second-class constraints, which leads to the extra even mode.

Although gravitational actions diverge in asymptotically anti-de Sitter spacetimes, boundary counterterms can be added in order to cancel out those divergences; such counterterms are known in general to third-order in the Riemann tensor for the Einstein-Hilbert action. Considering foliations of anti-de Sitter with an $S^m\times H^{d-m}$ boundary, we discuss a simple algorithm which we use to generate counterterms up to sixth order in the Riemann tensor, for the Einstein-Hilbert, Gauss-Bonnet and third-order-Lovelock Lagrangians. We also comment on other theories such as $F(R)$ gravity.

We study an extension of the Higgs sector of the minimal supersymmetric standard model (MSSM), considering the effects of new degrees of freedom at the TeV scale and allowing for sources of $CP$ violation beyond the MSSM. We analyze the impact of the beyond-the-MSSM sources of $CP$ violation on the Higgs collider phenomenology and on low energy flavor and $CP$-violating observables. We identify distinct Higgs collider signatures that cannot be realized, either in the case without $CP$-violating phases or in the $CP$-violating MSSM, and investigate the prospects to probe them at the Tevatron and the LHC. The most striking benchmark scenario has three neutral Higgs bosons that all decay dominantly into $W$ boson pairs and that are well within the reach of the 7 TeV LHC run. On the other hand, we also present scenarios with three Higgs bosons that have masses $M_{H_i}\gtrsim 150\mathrm{GeV}$ and decay dominantly into $b\overline{b}$. Such scenarios are much more challenging to probe and can even lie completely outside the reach of the 7 TeV LHC run. We explore complementary scenarios with standard MSSM Higgs signals that allow us to accommodate a nonstandard $B_s$ mixing phase as indicated by D0, as well as the excess in $B_s\to {\mu }^{+}{\mu }^{-}$ candidates recently reported by CDF. We find that, in contrast to the MSSM, a minimal flavor-violating soft sector is sufficient to generate significant corrections to $CP$-violating observables in meson mixing, compatible with Electric Dipole Moment constraints. In particular, a $B_s$ mixing phase $S_{\psi \varphi }\lesssim 0.15$ can be achieved for specific regions of parameter space, compatible with all the presently available experimental constraints on flavor observables. Such a nonstandard $B_s$ mixing phase would unambiguously imply a sizable suppression of $S_{\psi K_S}$ with respect to the standard model prediction and a $\mathrm{BR}(B_s\to {\mu }^{+}{\mu }^{-})$ close to its 95% C.L. upper bound of $1.1\times {10}^{-8}$.

We investigate collider signatures of a top-philic $W^{\prime }$ model, in which the $W^{\prime }$ boson couples only to the third-generation quarks of the standard model. The main discovery channel for this $W^{\prime }$ is through associated production of the $W^{\prime }$ and top quark, yielding a top-quark pair plus an extra bottom-quark jet as a signal. We do a full simulation of the signal and relevant backgrounds. We develop a method of analysis that allows us to conclude that discovery of the $W^{\prime }$ is promising at the LHC despite large standard model backgrounds. Bottom-quark tagging of the extra jet is key to suppressing the backgrounds.

In high energy hadronic collisions, a scalar or pseudoscalar Higgs boson, $\Phi =H$, $A$, can be efficiently produced via gluon fusion, which is mediated by heavy quark loops. In this paper, we consider double real emission corrections to $\Phi =A$ production, which lead to a Higgs plus two-jet final state, at order ${\alpha }_s^4$. Full quark mass effects are considered in the calculation of scattering amplitudes for the $\mathcal{C}\mathcal{P}$-odd Higgs boson $A$, as induced by quark triangle-, box-, and pentagon-diagrams. They complement the analogous results for a $\mathcal{C}\mathcal{P}$-even Higgs boson $H$ in Ref. [1]. Interference effects between loops with top and bottom quarks as well as between $\mathcal{C}\mathcal{P}$-even and $\mathcal{C}\mathcal{P}$-odd couplings of the heavy quarks are fully taken into account.

We calculate the next-to-leading-order cross section for the inclusive production of $B$ mesons in $pp$ collisions in the general-mass variable-flavor-number scheme, an approach that takes into account the finite mass of the $b$ quarks. We use realistic evolved nonperturbative fragmentation functions obtained from fits to $e^{+}{e}^{-}$ data and compare our results for the transverse-momentum and rapidity distributions at a center-of-mass energy of 7 TeV with recent data from the CMS Collaboration at the CERN LHC. We find good agreement, in particular, at large values of $p_T$.

The unusual multiplet structures associated with the light spin zero mesons have recently attracted a good deal of theoretical attention. Here we discuss some aspects associated with the possibility of getting new experimental information on this topic from semileptonic decays of heavy charged mesons into an isosinglet scalar or pseudoscalar plus leptons.

The physical meaning of structure scalars is analyzed for charged dissipative spherical fluids and for neutral dust in the presence of cosmological constant. The role played by such factors in the structure scalars is clearly brought out and physical consequences are discussed. Particular attention needs to be paid to the changes introduced by the above mentioned factors in the inhomogeneity factor and the evolution of the expansion scalar and the shear tensor.

We analyze the position and momentum uncertainties of the energy eigenstates of the harmonic oscillator in the context of a deformed quantum mechanics, namely, that in which the commutator between the position and momentum operators is given by $[\widehat{x},\widehat{p}]=i\hslash (1+\beta {\widehat{p}}^2)$. This deformed commutation relation leads to the minimal length uncertainty relation $\Delta x\ge (\hslash /2)(1/\Delta p+\beta \Delta p)$, which implies that $\Delta x\sim 1/\Delta p$ at small $\Delta p$ while $\Delta x\sim \Delta p$ at large $\Delta p$. We find that the uncertainties of the energy eigenstates of the normal harmonic oscillator ($m>0$), derived in L. N. Chang, D. Minic, N. Okamura, and T. Takeuchi, Phys. Rev. D 65, 125027 (2002), only populate the $\Delta x\sim 1/\Delta p$ branch. The other branch, $\Delta x\sim \Delta p$, is found to be populated by the energy eigenstates of the “inverted” harmonic oscillator ($m<0$). The Hilbert space in the inverted case admits an infinite ladder of positive energy eigenstates provided that $\Delta x_{\min }=\hslash \sqrt{\beta }>\sqrt{2}[{\hslash }^2/k|m|{]}^{1/4}$. Correspondence with the classical limit is also discussed.

If the generalized dynamics of K field theories (i.e., field theories with a nonstandard kinetic term) is taken into account, then the possibility of so-called twinlike models opens up, that is, of different field theories which share the same topological defect solution with the same energy density. These twinlike models were first introduced in [M. Andrews, M. Lewandowski, M. Trodden, and D. Wesley, Phys. Rev. D 82, 105006 (2010)], where the authors also considered possible cosmological implications and gave a geometric characterization of twinlike models. A further analysis of the twinlike models was accomplished in [D. Bazeia, J. D. Dantas, A. R. Gomes, L. Losano, and R. Menezes, Phys. Rev. D 84, 045010 (2011)], with the help of the first order formalism, where also the case with gravitational self-interaction was considered. Here we show that by combining the geometric conditions of [M. Andrews, M. Lewandowski, M. Trodden, and D. Wesley, Phys. Rev. D 82, 105006 (2010)], with the first order formalism of [D. Bazeia, J. D. Dantas, A. R. Gomes, L. Losano, and R. Menezes, Phys. Rev. D 84, 045010 (2011)], one may easily derive a purely algebraic method to explicitly calculate an infinite number of twin field theories for a given theory. We determine this algebraic construction for the cases of scalar field theories, supersymmetric scalar field theories, and self-gravitating scalar fields. Further, we give several examples for each of these cases.