The large-scale structure of the Universe suggests that the physics underlying its early evolution is scale-free. This was the historic motivation for the Harrison-Zel’dovich-Peebles spectrum and for inflation. Based on a hydrodynamical approach, we identify scale-free forms for the background equation of state for both inflationary and cyclic scenarios and use these forms to derive predictions for the spectral tilt and tensor-to-scalar ratio of primordial density perturbations. For the case of inflation, we find three classes of scale-free models with distinct predictions. Including all classes, we show that scale-free inflation predicts tensor-to-scalar ratio $r>10^{-4}$. We show that the observationally favored class is theoretically disfavored because it suffers from an initial conditions problem and the hydrodynamical form of an unlikeliness problem similar to that identified recently for certain inflaton potentials. We contrast these results with those for scale-free cyclic models.

Parity violation in the cosmic microwave background (CMB) radiation has been confirmed by recent Planck observation. In this paper, we extend our previous work [P. Naselsky et al., Astrophys. J. 749, 31 (2012)] on the directional properties of CMB parity asymmetry by considering the Planck data of the CMB temperature anisotropy. We define six kinds of the directional statistics and find that they all indicate the odd-parity preference of CMB data. In addition, we find the preferred axes of all these statistics strongly correlate with the preferred axes of the CMB kinematic dipole, quadrupole, and octopole. The alignment between them is confirmed at more than $3\sigma$ confidence level, which implies that the CMB parity asymmetry, and the anomalies of the CMB quadrupole and octopole, may have the common physical, contaminated, or systematic origin. In addition, they all should be connected with the possible contamination of the residual dipole component.

Soon the number of type Ia supernova (SN) measurements should exceed 100 000. Understanding the effect of weak lensing by matter structures on the supernova brightness will then be more important than ever. Although SN lensing is usually seen as a source of systematic noise, we will show that it can be in fact turned into signal. More precisely, the non-Gaussianity introduced by lensing in the SN Hubble diagram dispersion depends rather sensitively on the amplitude ${\sigma }_8$ of the matter power spectrum. By exploiting this relation, we are able to predict constraints on ${\sigma }_8$ of 7% (3%) for a catalog of 100 000 (500 000) SNe of average magnitude error 0.12, without having to assume that such intrinsic dispersion and its redshift evolution are known a priori. The intrinsic dispersion has been assumed to be Gaussian; possible intrinsic non-Gaussianities in the data set (due to the SN themselves and/or to other transients) could be potentially dealt with by means of additional nuisance parameters describing higher moments of the intrinsic dispersion distribution function. This method is independent of and complementary to the standard methods based on cosmic microwave background, cosmic shear, or cluster abundance observables.

In a recent paper Y. Hidaka and A. Yamamoto [Phys. Rev. D 87, 094502 (2013)] claim—using both analytical and numerical approaches—that the charged $\mathrm{\rho }$ mesons cannot condense in the vacuum subjected to a strong magnetic field. In this Comment we point out that both the analytical and numerical results of this paper are consistent with the inhomogeneous $\rho$-meson condensation. Furthermore, we show that the numerical results of the paper support the presence of the expected (in quenched lattice QCD) crossover transition driven by the $\rho$-meson condensation. Finally, we stress that the inhomogeneous $\rho$-meson condensation is consistent with both Vafa-Witten and Elitzur theorems.

Using the Higgs boson mass $m_h=125\mathrm{GeV}$, the radiative Higgs decays $h\to \gamma {\nu }_l{\overline{\nu }}_l$ with ${\nu }_l={\nu }_e$, ${\nu }_{\mu }$, and ${\nu }_{\tau }$ are analyzed in the standard model. Our calculation shows that the inclusive width of these processes, i.e., the sum of $\mathrm{\Gamma }(h\to \gamma {\nu }_l{\overline{\nu }}_l)$ for ${\nu }_l={\nu }_e$, ${\nu }_{\mu }$, ${\nu }_{\tau }$, is 1.41 keV, which is about 15% of $\mathrm{\Gamma }(h\to \gamma \gamma )$. Therefore, the observation of these channels in future precise experiments may provide some useful information on the Higgs physics in both the standard model and its possible extensions.

We investigate a possibility of the “flatland scenario,” in which the electroweak gauge symmetry is radiatively broken via the Coleman-Weinberg mechanism starting from a completely flat Higgs potential at the Planck scale. We show that the flatland scenario is realizable only when an inequality $K<1$ among the coefficients of the $\beta$ functions is satisfied. We show several models satisfying the condition.

We consider three-loop corrections to hyperfine splitting in muonium generated by the gauge invariant set of diagrams with a virtual light-by-light scattering block. These diagrams produce both recoil and nonrecoil contributions to hyperfine splitting. Recoil corrections are enhanced by large logarithms of the muon-electron mass ratio. Both nonrecoil and logarithmically enhanced radiative-recoil corrections were calculated some time ago. Here we calculate nonlogarithmic radiative-recoil corrections generated by the insertions of the light-by-light scattering block.

The ${\overline{B}}_s^0\to D_s^{(*)+}{l}^{-}{\overline{\nu }}_l$ semileptonic decays were calculated in the framework of the standard model by employing the perturbative QCD (pQCD) factorization approach. We defined four ratios of the branching ratios of the considered decays $R(D_s^{(*)})$ and $R_{D_s}^{l,\tau }$. From the numerical results and phenomenological analysis we found that (a) the pQCD predictions for the branching ratios $Br({\overline{B}}_s^0\to D_s^{(*)+}{l}^{-}{\overline{\nu }}_l)$ generally agree well with the previous theoretical predictions, (b) for the four ratios, the pQCD predictions are $R(D_s)=0.392\pm 0.022$, $R(D_s^{*})=0.302\pm 0.011$, $R_{D_s}^l=0.448_{-0.041}^{+0.058}$, and $R_{D_s}^{\tau }=0.582_{-0.045}^{+0.071}$, which show a very good $SU{(3)}_F$ flavor symmetry with the corresponding ratios for $B\to D^{(*)}{l}^{-}{\overline{\nu }}_l$ decays, and (c) we strongly suggest the measurements of the new ratios $R(D_s^{(*)})$ and $R_{D_s}^{l,\tau }$ in the forthcoming Super-B experiments.

We present in detail a new systematic method which can be used to automatically eliminate the renormalization scheme and scale ambiguities in perturbative QCD predictions at all orders. We show that all of the nonconformal $\beta$-dependent terms in a QCD perturbative series can be readily identified by generalizing the conventional renormalization schemes based on dimensional regularization. We then demonstrate that the nonconformal series of pQCD at any order can be resummed systematically into the scale of the QCD coupling in a unique and unambiguous way due to a special degeneracy of the $\beta$ terms in the series. The resummation follows from the principal of maximum conformality (PMC) and assigns a unique scale for the running coupling at each perturbative order. The final result is independent of the initial choices of renormalization scheme and scale, in accordance with the principles of the renormalization group, and thus eliminates an unnecessary source of systematic error in physical predictions. We exhibit several examples known to order ${\alpha }_s^4$; i.e. (i) the electron-positron annihilation into hadrons, (ii) the tau-lepton decay to hadrons, (iii) the Bjorken and Gross-Llewellyn Smith (GLS) sum rules, and (iv) the static quark potential. We show that the final series of the first three cases are all given in terms of the anomalous dimension of the photon field in $SU(N)$, in accordance with conformality, and with all nonconformal properties encoded in the running coupling. The final expressions for the Bjorken and GLS sum rules directly lead to the generalized Crewther relations, exposing another relevant feature of conformality. The static quark potential shows that PMC scale-setting in the Abelian limit is to all orders consistent with QED scale-setting. Finally, we demonstrate that the method applies to any renormalization scheme and can be used to derive commensurate scale relations between measurable effective charges, which provide nontrivial tests of QCD to high precision. This work extends Brodsky-Lepage-Mackenzie (BLM) scale-setting to any perturbative order, with no ambiguities in identifying $\beta$ terms in pQCD, demonstrating that BLM scale-setting follows from a principle of maximum conformality.

Recent lattice QCD simulations of the scattering lengths of Nambu-Goldstone bosons off the $D$ mesons are studied using unitary chiral perturbation theory. We show that the lattice QCD data are better described in the covariant formulation than in the heavy-meson formulation. The $D_{s0}^{*}(2317)$ can be dynamically generated from the coupled-channels $DK$ interaction without a priori assumption of its existence. A new renormalization scheme is proposed which manifestly satisfies chiral power counting rules and has well-defined behavior in the infinite heavy-quark mass limit. Using this scheme we predict the heavy-quark spin and flavor symmetry counterparts of the $D_{s0}^{*}(2317)$.

In this paper we study the reaction $e^{+}{e}^{-}\to {(D^{*}{\overline{D}}^{*})}^{\pm }{\pi }^{\mp }$ in which the BESIII collaboration has claimed the existence of a $1^{+}$ resonance, named $Z_c(4025)$, in the $D^{*}{\overline{D}}^{*}$ invariant mass spectrum with a mass around 4026 MeV and width close to 26 MeV . We determine the $D^{*}{\overline{D}}^{*}$ invariant mass distribution and find that although the explanation considered by the BESIII collaboration is plausible, there are others which are equally possible, like a $2^{+}$ resonance or a bound state. Even more, we find that the data can be explained without the existence of a resonance/bound state. In view of the different possible interpretations found for the BESIII data, we try to devise a strategy which could help in identifying the origin of the signal reported by the BESIII collaboration. For this, we study the dependence of the $D^{*}{\overline{D}}^{*}$ spectrum considering the different options as a function of the total center-of-mass energy. We arrive at the conclusion that increasing the center-of-mass energy from 4.26 GeV to 4.6 GeV can be useful to distinguish between a resonance, a bound state or just a pure background as being responsible for the signal found. This information should be useful for future experiments.

We apply collinear expansion to inclusive hadron production in $e^{+}{e}^{-}$ annihilation and derive a formalism suitable for systematic study of leading as well as higher-twist contributions to fragmentation functions at the tree level. We make the calculations for hadrons with spin-0, spin-$1/2$ as well as spin-1 and obtain the results in terms of different components of fragmentation functions for the hadronic tensors, the differential cross section as well as hadron polarizations in different cases. The results show a number of interesting features such as the existence of transverse polarization for spin-$1/2$ hadrons at the twist-3 level, the quark polarization independence of the spin alignment of vector mesons.

The possibility of observing supernova (SN) neutrinos through the process of coherent elastic neutrino-nucleus scattering (CENNS) in future ton scale detectors designed primarily for direct detection of dark matter is investigated. In particular, we focus on the possibility of distinguishing the various phases of the SN neutrino emission. The neutrino emission rates from the recent long-term Basel/Darmstadt simulations are used to calculate the expected event rates. The recent state-of-the-art SN simulations predict closer fluxes among different neutrino flavors and lower average energies compared to the earlier simulation models. The estimated total event rates are found to be typically a factor of 2 lower than those predicted using older simulation models. We find that future 1-ton class Xe detectors will be able to detect neutrinos from a SN at a distance of 10 kpc provided they have relatively low nuclear recoil energy thresholds of $\lesssim 1\mathrm{keV}$. At the same time, with an optimistic threshold of $\sim 1\mathrm{keV}$, demarcating the neutrinos associated with the accretion phase of a SN at 10 kpc from the Earth will require 10-ton class Xe detectors, while distinguishing the neutrinos associated with the neutronization burst phase of the explosion would typically require several tens of ton detectors. We also comment on the possibility of studying the properties of nonelectron flavor neutrinos from the CENNS of SN neutrinos.

We investigate the implication of different elastic spin-dependent (SD) operators on both the direct and indirect detections of the weakly interacting massive particle (WIMP). Six representative building blocks of SD operators, together with their counterparts with a massless mediator, are considered to interpret the direct detection experiments (Xenon100, SIMPLE, and COUPP) in a comprehensive way. We also study the solar capture and annihilation of WIMPs with these effective SD operators and place the constraints on the relevant annihilation rate from neutrino detection experiments Super-Kamionkande and IceCube. Upper limits on the WIMP-nucleon couplings drawn from direct detections are also projected to the annihilation rate for contrast and complementarity. We find that the efficiency of these mentioned detection strategies depends specifically on the six SD operators, while the neutrino-based detections are more effective in exploring the parameter space for the massless mediator scenario.

We show that any model with a homogeneous relationship among elements of the neutrino mass matrix with one mass hierarchy yields predictions for the oscillation parameters and Majorana phases similar to those given by a model with the same homogeneous relationship among cofactors of the neutrino mass matrix with the opposite mass hierarchy, except when the lightest mass is of order 20 meV or less.

We report on a search for eleven lepton-number violating processes $B^{+}\to X^{-}{\ell }^{+}{\ell }^{\prime +}$ with $X^{-}=K^{-}$, ${\pi }^{-}$, ${\rho }^{-}$, $K^{*-}$, or $D^{-}$ and ${\ell }^{+}/{\ell }^{\prime +}=e^{+}$ or ${\mu }^{+}$, using a sample of $471\pm 3$ million $B\overline{B}$ events collected with the BABAR detector at the PEP-II $e^{+}{e}^{-}$ collider at the SLAC National Accelerator Laboratory. We find no evidence for any of these modes and place 90% confidence level upper limits on their branching fractions in the range $(1.5–26)\times 10^{-7}$.

In the context of dynamical breaking of local supersymmetry (supergravity), including the Deser-Zumino super-Higgs effect, for the simple but quite representative cases of $\mathcal{N}=1$, $D=4$ supergravity, we discuss the emergence of Starobinsky-type inflation, due to quantum corrections in the effective action arising from integrating out gravitino fields in their massive phase. This type of inflation may occur after a first-stage small-field inflation that characterizes models near the origin of the one-loop effective potential, and it may occur at the nontrivial minima of the latter. Phenomenologically realistic scenarios, compatible with the Planck data, may be expected for the conformal supergravity variants of the basic model.

We construct the local Gribov-Zwanziger action for SU(2) Euclidean Yang-Mills theories in the maximally Abelian (MA) gauge with $\mathrm{U}(1{)}_3$ Landau gauge fixing based on Zwanziger’s work in the Landau gauge. By restricting the functional integral region to the Gribov region in the MA gauge, we give the nonlocal action. We localize the action with new fields and obtain the action with the shift of the new scalar fields, which has the terms corresponding to the localized action of the horizon function in the MA gauge. The diagonal gluon propagator in the MA gauge at tree level behaves like the propagator from the Gribov-Zwanziger action in the Landau gauge, and shows the violation of the Kallen-Lehmann representation. From our result, the validity of the Gribov-Zwanziger scenario in the MA gauge can be studied by comparing with the lattice result in two dimensions, which is qualitatively consistent with the result of the original Gribov-Zwanziger action in the Landau gauge.

In this work, we study the radiative generation of the Lorentz-violating Euler-Heisenberg action, in the weak field approximation. For this, we first consider a nonperturbative calculation in the coefficient $c_{\mu \nu }$, however, by assuming rotational invariance. Within this approach, we also obtain the results of the amplitude for the photon triple splitting. In the following, we take into account the perturbative approach, where $c_{\mu \nu }$ is treated as a insertion in the propagator and a new vertex. The partial results are in fact an expansion up to first order in $c_{\mu \nu }$ of the nonperturbative ones, with $c_{00}=\kappa$ and $c_{0i}=c_{ij}=0$. This suggests that the complete results obtained in the nonperturbative approach can be used in both treatments.

Quantum physics on manifolds with boundary brings novel aspects due to boundary conditions. One important feature is the appearance of localized negative eigenmodes for the Laplacian on the boundary. These can potentially lead to instabilities. We consider quantum field theories on such manifolds and interpret these as leading to the onset of phase transitions.