We consider the physics and collider phenomenology of quirks that transform nontrivially under QCD color, $SU(2{)}_W$ as well as an $SU(N{)}_{ic}$ infracolor group. Our main motivation is to show that the recent $Wjj$ excess observed by CDF naturally arises in quirky models. The basic pattern is that several different quirky states can be produced, some of which $\beta$ decay during or after spin-down, leaving the lightest electrically-neutral quirks to hadronize into a meson that subsequently decays into gluon jets. We analyze LEP II, Tevatron, UA2, and electroweak precision constraints, identifying the simplest viable models: scalar quirks (“squirks”) transforming as color triplets, $SU(2{)}_W$ triplets and singlets, all with vanishing hypercharge. We calculate production cross sections, weak decay, spin-down, meson decay rates, and estimate efficiencies. The novel features of our quirky model includes: quirkonium decay proceeds into a pair of gluon jets, without a $b$-jet component; there is essentially no associated $Zjj$ or $\gamma jj$ signal; and there are potentially new (parameter-dependent) contributions to dijet production, multi-$W$ production plus jets, $W\gamma$, $\gamma \gamma$ resonance signals, and monojet signals. There may be either underlying event from low energy QCD deposition resulting from quirky spin-down and/or qualitatively modified event kinematics from infraglueball emission.

We present a numerical study of spectroscopic observables in the SU(2) gauge theory with two adjoint fermions using improved source and sink operators. We compare in detail our improved results with previous determinations of masses that used point sources and sinks and we investigate possible systematic effects in both cases. Such comparison enables us to clearly assess the impact of a short temporal extent on the physical picture, and to investigate some effects due to the finite spatial box. While confirming the IR-conformal behavior of the theory, our investigation shows that in order to make firm quantitative predictions, a better handle on finite size effects is needed.

The Higgs boson production is investigated in proton-proton collisions at next-to-leading-order accuracy in central exclusive diffractive processes at the LHC. The production process by the double Pomeron exchange is analyzed in the diffractive factorization through the Ingelman-Schlein approach, taking into account the parton content of the Pomeron by the diffractive partonic distribution function provided by the H1 Collaboration. Hence, we estimate the production cross section of the Higgs boson, as well as its rapidity distribution for distinct energies of the LHC. Also, we include the gap survival probability in our calculation, which is studied in recent works and expected to lie in the range between $1\%$ and $5\%$ for the energy regime of 14 TeV. As a result, we found a production cross section of about 0.3–0.8 (1.2–3.7) fb at 7 (14) TeV, being of the same order as predicted by the two-photon and the Balitsky-Fadin-Kuraev-Lipatov Pomeron mechanisms. Therefore, assuming the selection rules of spin-parity properties, the exclusive production is a promising channel for the Higgs boson detection in the LHC.

A physical interpretation of the two-sheeted space, the most fundamental ingredient of noncommutative spectral geometry proposed by Connes as an approach to unification, is presented. It is shown that the doubling of the algebra is related to dissipation and to the gauge structure of the theory, the gauge field acting as a reservoir for the matter field. In a regime of completely deterministic dynamics, dissipation appears to play a key role in the quantization of the theory, according to the ’t Hooft’s conjecture. It is thus argued that the noncommutative spectral geometry classical construction carries the seeds of quantization, implicit in its feature of the doubling of the algebra.

We present two new results on relativistic hydrodynamics with anomalies and external electromagnetic fields, “chiral magnetohydrodynamics” (CMHD). First, we study CMHD in four dimensions at second order in the derivative expansion assuming the conformal/Weyl invariance. We classify all possible independent conformal second order viscous corrections to the energy-momentum tensor and to the $U(1)$ current in the presence of external electric and/or magnetic fields, and identify 18 terms that originate from the triangle anomaly. We then propose and motivate the following guiding principle to constrain the CMHD: the anomaly–induced terms that are even under the time-reversal invariance should not contribute to the local entropy production rate. This allows us to fix 13 out of the 18 transport coefficients that enter the second order formulation of CMHD. We also relate one of our second order transport coefficients to the chiral shear waves. Our second subject is hydrodynamics with ($N+1$)-gon anomaly in an arbitrary $2N$ dimensions. The effects from the ($N+1$)-gon anomaly appear in hydrodynamics at ($N-1$)th order in the derivative expansion, and we identify precisely $N$ such corrections to the $U(1)$ current. The time-reversal constraint is powerful enough to allow us to find the analytic expressions for all transport coefficients. We confirm the validity of our results (and of the proposed guiding principle) by an explicit fluid/gravity computation within the AdS/CFT correspondence.

In the context of softly broken $\mathcal{N}=2$ supersymmetric quantum chromodynamics, with a hierarchical gauge symmetry breaking $SU(N+1)\stackrel{v_1}{\to }U(N)\stackrel{v_2}{\to }\mathbf{1}$, $v_1\gg v_2$, we construct monopole-vortex complex solitonlike solutions and examine their properties. They represent the minimum of the static energy under the constraint that the monopole and antimonopole positions sitting at the extremes of the vortex are kept fixed. They interpolate the ’t Hooft-Polyakov-like regular monopole solution near the monopole centers and a vortex solution far from them and in between. The main result, obtained in the theory with $N_f=N$ equal-mass flavors, is concerned with the existence of exact orientational $\mathbb{C}{P}^{N-1}$ zero modes, arising from the exact color-flavor diagonal $SU(N{)}_{C+F}$ global symmetry. The “unbroken” subgroup $SU(N)\subset SU(N+1)$, with which the naive notion of non-Abelian monopoles and the related difficulties were associated, is explicitly broken at low energies. The monopole transforms nevertheless according to the fundamental representation of a new exact, unbroken $SU(N)$ symmetry group, as does the vortex attached to it. We argue that this explains the origin of the dual non-Abelian gauge symmetry.

We investigate how gravity affects Q-balls by exemplifying the case of the Affleck-Dine potential $V(\varphi )≔m^4\ln (1+\frac{{\varphi }^2}{m^2})$. Surprisingly, stable Q-balls with arbitrarily small charge exist, no matter how weak gravity is, contrary to the case of flat spacetime. We also show analytically that this feature holds true for general models as long as the leading order term of the potential is a positive mass term in its Maclaurin series.

The Higgs triplet model (HTM) of neutrino mass generation predicts the existence of doubly charged Higgs bosons ($H^{\pm \pm }$). In the HTM a scalar eigenstate ($H_2$) is dominantly composed of the scalar field from the isospin doublet, and could be significantly heavier than $H^{\pm \pm }$. Such a scenario would allow the possibility of a large branching ratio for the decay $H_2\to H^{++}{H}^{--}$. From the production mechanism of gluon-gluon fusion, $gg\to H_2$, the above decay mode would give rise to pair production of doubly charged Higgs bosons ($H^{++}{H}^{--}$) with a cross section which could be significantly larger than the cross sections for the standard production mechanisms $q\overline{q}\to \gamma$, $Z\to H^{++}{H}^{--}$, and $q^{\prime }\overline{q}\to W\to H^{\pm \pm }{H}^{\mp }$. We discuss the phenomenological consequences for the ongoing searches for $H^{\pm \pm }$ at the Tevatron and at the LHC.

We reexamine the question of measuring the weak phase $\gamma$ in $B\to K\pi \pi$ decays. To this end, we express all $B\to K\pi \pi$ amplitudes in terms of diagrams. We show that, as in $B\to K\pi$, relations exist between certain tree and electroweak-penguin diagrams. The imposition of these relations allows the extraction of $\gamma$ from measurements of the $B\to K\pi \pi$ observables. We estimate the theoretical error in this method to be $O(5\%)$.

We express the amplitudes for charmless three-body $B$ decays in terms of diagrams. In addition, we show how to use Dalitz-plot analyses to obtain decay amplitudes which are symmetric or antisymmetric under the exchange of two of the final-state particles. When annihilation/exchange-type diagrams are neglected, as in two-body decays, many of the exact, purely isospin-based results are modified, leading to new tests of the standard model. Some of the tests can be performed now, and we find that present data agree with the predictions of the standard model. Furthermore, contrary to what was thought previously, it is possible to cleanly extract weak-phase information from three-body decays, and we discuss methods for $B\to K\pi \pi$, $KK\overline{K}$, $K\overline{K}\pi$, and $\pi \pi \pi$.

The nonisotropic nature of the neutrino emission from a supernova (SN) core might potentially affect the flavor evolution of the neutrino ensemble, via neutrino-neutrino interactions in the deepest SN regions. We investigate the dependence of these “multiangle effects” on the original SN neutrino fluxes in a three-flavor framework. We show that the pattern of the spectral crossings (energies where $F_{{\nu }_e}=F_{{\nu }_x}$, and $F_{{\overline{\nu }}_e}=F_{{\overline{\nu }}_x}$) is crucial in determining the impact of multiangle effects on the flavor evolution. For neutrino spectra presenting only a single crossing, synchronization of different angular modes prevails over multiangle effects, producing the known “quasi-single-angle” evolution. Conversely, in the presence of spectra with multiple crossing energies, synchronization is not stable. In this situation, multiangle effects would produce a sizable delay in the onset of the flavor conversions, as recently observed. We show that, due to the only partial adiabaticity of the evolution at large radii, the multiangle suppression can be so strong to dramatically affect the final oscillated neutrino spectra. In particular three-flavor effects, associated with the solar parameters, could be washed out in multiangle simulations.

It was pointed out some time ago that there can be two variations in which the divergences of a quantum field theory can be tamed using the ideas presented by Lee and Wick. In one variation the Lee-Wick partners of the normal fields live in an indefinite metric Hilbert space but have positive energy and in the other variation the Lee-Wick partners can live in a normal Hilbert space but carry negative energy. Quantum mechanically the two variations mainly differ in the way the fields are quantized. In this article the second variation of Lee and Wick’s idea is discussed. Using statistical mechanical methods the energy density, pressure and entropy density of the negative energy Lee-Wick fields have been calculated. The results exactly match with the thermodynamic results of the conventional, positive energy Lee-Wick fields. The result sheds some light on the second variation of Lee-Wick’s idea. The result seems to say that the thermodynamics of the theories do not care about the way they are quantized.

The nonlinear aspects of a recently proposed model of massive spin-2 particles with propagating torsion are studied. We obtain a nonlinear equation which reduces at linear order to a generalized Fierz-Pauli equation in any background space-time with or without a vanishing torsion. We contrast those results with properties of a class of bigravity theories in an arbitrary background Einstein manifold. It is known that the nonperturbative spectrum of the bigravity model has 8 propagating physical degrees of freedom. This is identical to the physical propagating degrees of freedom of the massive spin-2 torsion model at the linearized order. The obtained nonlinear version of the Fierz-Pauli field equations, however, contains terms absent in the bigravity case which indicates that the curved space generalization of the unique flat space Fierz-Pauli equation is not unique. Moreover, in the torsion massive gravity model the Fierz-Pauli field appears as a derivative of fundamental fields. This, however, does not generate any unwanted pole once coupled to some external sources.

We study the absorption of a massless scalar field by a static black hole. Using the continuity equation that arises from the Klein-Gordon equation, it is possible to define a normalized absorption rate $\Gamma (t)$ for the scalar field as it falls into the black hole. It is found that the absorption mainly depends upon the characteristics wavelengths involved in the physical system: the mean wave number and the width of the wave packet, but that it is insensitive to the scalar field’s strength. By taking a limiting procedure, we determine the minimum absorption fraction of the scalar field’s mass by the black hole, which is around 50%.

Recent studies have shown that the number counts of convergence peaks $N(\kappa )$ in weak lensing (WL) maps, expected from large forthcoming surveys, can be a useful probe of cosmology. We follow up on this finding, and use a suite of WL convergence maps, obtained from ray-tracing N-body simulations, to study (i) the physical origin of WL peaks with different heights, and (ii) whether the peaks contain information beyond the convergence power spectrum $P_{\ell }$. In agreement with earlier work, we find that high peaks (with amplitudes $\gtrsim 3.5\sigma$, where $\sigma$ is the r.m.s. of the convergence $\kappa$) are typically dominated by a single massive halo. In contrast, medium-height peaks ($\approx 0.5–1.5\sigma$) cannot be attributed to a single collapsed dark matter halo, and are instead created by the projection of multiple (typically, 4–8) halos along the line of sight, and by random galaxy shape noise. Nevertheless, these peaks dominate the sensitivity to the cosmological parameters $w$, ${\sigma }_8$, and ${\Omega }_m$. We find that the peak-height distribution and its dependence on cosmology differ significantly from predictions in a Gaussian random field. We directly compute the marginalized errors on $w$, ${\sigma }_8$, and ${\Omega }_m$ from the $N(\kappa )+P_{\ell }$ combination, including redshift tomography with source galaxies at $z_s=1$ and $z_s=2$. We find that the $N(\kappa )+P_{\ell }$ combination has approximately twice the cosmological sensitivity compared to $P_{\ell }$ alone. These results demonstrate that $N(\kappa )$ contains non-Gaussian information complementary to the power spectrum.

We study preheating in models where the inflaton has a noncanonical kinetic term, containing powers of the usual kinetic energy. The inflaton field oscillating about its potential minimum acts as a driving force for particle production through parametric resonance. Noncanonical kinetic terms can impose a speed limit on the motion of the inflaton, modifying the oscillating inflaton profile. This has two important effects: it turns a smooth sinusoidal profile into a sharp saw-tooth, enhancing resonance, and it lengthens the period of oscillations, suppressing resonance. We show that the second effect dominates over the first, so that preheating with a noncanonical inflaton field is less efficient than with canonical kinetic terms, and that the expansion of the Universe suppresses resonance even further.

Based only on the assumption that the Universe is homogenous and isotropic on large scales, cosmography is an ideal tool to investigate the cosmic expansion history in an almost model-independent way. Fitting the data on the luminosity distance and baryon acoustic oscillations allows to determine the confidence ranges for the cosmographic parameters hence giving some quantitative constraints that at whatever theory has to fulfill. As an application, we consider here the case of teleparallel gravity also referred to as $f(T)$ gravity. To this end, we first work out analytical expressions to express the present day values of $f(T)$ derivatives as a function of the cosmographic parameters, which hold under quite general and physically motivated conditions. We then use the constraints coming from cosmography to find out the confidence ranges for $f(T)$ derivatives up to the fifth order and show how these can be used to check the viability of given teleparallel gravity models without the need to explicitly solve the second order dynamic equations.

We measure the halo power spectrum in redshift space from cosmological $N$-body simulations, and test the analytical models of redshift distortions particularly focusing on the scales of baryon acoustic oscillations. Remarkably, the measured halo power spectrum in redshift space exhibits a large-scale enhancement in amplitude relative to the real-space clustering, and the effect becomes significant for the massive or highly biased halo samples. These findings cannot be simply explained by the so-called streaming model frequently used in the literature. By contrast, a physically motivated perturbation theory model developed in the previous paper reproduces the halo power spectrum very well, and the model combining a simple linear scale-dependent bias can accurately characterize the clustering anisotropies of halos in two dimensions, i.e., line-of-sight and its perpendicular directions. The results highlight the significance of nonlinear coupling between density and velocity fields associated with two competing effects of redshift distortions, i.e., Kaiser and Finger-of-God effects, and a proper account of this effect would be important in accurately characterizing the baryon acoustic oscillations in two dimensions.

We study the possibility of getting infinite energy in the center-of-mass frame of colliding charged particles in a general stationary charged black hole. For black holes with twofold degenerate horizon, it is found that arbitrary high center-of-mass energy can be attained, provided that one of the particle has critical angular momentum or critical charge and the remained parameters of particles and black holes satisfy certain restriction. For black holes with multiple-fold degenerate event horizons, the restriction is released. For nondegenerate black holes, the ultrahigh center-of-mass is possible to be reached by invoking the multiple scattering mechanism. We obtain a condition for the existence of innermost stable circular orbit with critical angular momentum or charge on any-fold degenerate horizons, which is essential to get ultrahigh center-of-mass energy without fine-tuning problem. We also discuss the proper time spending by the particle to reach the horizon and the duality between frame-dragging effect and electromagnetic interaction. Some of these general results are applied to braneworld small black holes.

We show that conformal Chern-Simons gravity in three dimensions has various holographic descriptions. They depend on the boundary conditions on the conformal equivalence class and the Weyl factor, even when the former is restricted to asymptotic anti–de Sitter behavior. For constant or fixed Weyl factor our results agree with a suitable scaling limit of topologically massive gravity results. For varying Weyl factor we find an enhancement of the asymptotic symmetry group, the details of which depend on certain choices. We focus on a particular example where an affine $\widehat{u}(1)$ algebra related to holomorphic Weyl rescalings shifts one of the central charges by 1. The Weyl factor then behaves as a free chiral boson in the dual conformal field theory.