The null energy condition (NEC) can be violated in a consistent way in models with unconventional kinetic terms, notably, in Galileon theories and their generalizations. We make use of one of these, the scale-invariant kinetic braiding model, to discuss whether a universe can in principle be created by manmade processes. We find that, even though the simplest models of this sort can have both healthy Minkowski vacuum and a consistent NEC-violating phase, there is an obstruction for creating a universe in a straightforward fashion. To get around this obstruction, we design a more complicated model and present a scenario for the creation of a universe in the laboratory.

Area products for multihorizon stationary black holes often have intriguing properties, and are often (though not always) independent of the mass of the black hole itself (depending only on various charges, angular momenta, and moduli). Such products are often formulated in terms of the areas of inner (Cauchy) horizons and outer (event) horizons, and sometimes include the effects of unphysical “virtual” horizons. But the conjectured mass independence sometimes fails. Specifically, for the Schwarzschild–de Sitter [Kottler] black hole in ($3+1$) dimensions it is shown by explicit exact calculation that the product of event horizon area and cosmological horizon area is not mass independent. (Including the effect of the third “virtual” horizon does not improve the situation.) Similarly, in the Reissner-Nordstrom–anti-de Sitter black hole in ($3+1$) dimensions the product of the inner (Cauchy) horizon area and event horizon area is calculated (perturbatively), and is shown to be not mass independent. That is, the mass independence of the product of physical horizon areas is not generic. In spherical symmetry, whenever the quasilocal mass $m(r)$ is a Laurent polynomial in aerial radius, $r=\sqrt{A/4\pi }$, there are significantly more complicated mass-independent quantities, the elementary symmetric polynomials built up from the complete set of horizon radii (physical and virtual). Sometimes it is possible to eliminate the unphysical virtual horizons, constructing combinations of physical horizon areas that are mass independent, but they tend to be considerably more complicated than the simple products and related constructions currently being mooted in the literature.

We present a complete quantization of an approximately homogeneous and isotropic universe with small scalar perturbations. We consider the case in which the matter content is a minimally coupled scalar field and the spatial sections are flat and compact, with the topology of a three-torus. The quantization is carried out along the lines that were put forward by the authors in a previous work for spherical topology. The action of the system is truncated at second order in perturbations. The local gauge freedom is fixed at the classical level, although different gauges are discussed and shown to lead to equivalent conclusions. Moreover, descriptions in terms of gauge-invariant quantities are considered. The reduced system is proven to admit a symplectic structure, and its dynamical evolution is dictated by a Hamiltonian constraint. Then, the background geometry is polymerically quantized, while a Fock representation is adopted for the inhomogeneities. The latter is selected by uniqueness criteria adapted from quantum field theory in curved spacetimes, which determine a specific scaling of the perturbations. In our hybrid quantization, we promote the Hamiltonian constraint to an operator on the kinematical Hilbert space. If the zero mode of the scalar field is interpreted as a relational time, a suitable ansatz for the dependence of the physical states on the polymeric degrees of freedom leads to a quantum wave equation for the evolution of the perturbations. Alternatively, the solutions to the quantum constraint can be characterized by their initial data on the minimum-volume section of each superselection sector. The physical implications of this model will be addressed in a future work, in order to check whether they are compatible with observations.

Inflationary models predict a correlation between primordial density perturbations (scalar metric perturbations) and gravitational waves (tensor metric perturbations) in the form of a scalar-scalar-tensor three-point correlation, or bispectrum in Fourier space. The squeezed limit of this bispectrum implies a quadrupolar asymmetry in the observed local power spectrum for matter and galaxies. Here we show (like others before) that an infrared divergence in the amplitude of this power asymmetry predicted in single-field slow-roll models is canceled by projection effects when considering the observed power spectrum. We then further evaluate the nonzero, but finite, residual quadrupolar power asymmetry that remains after the divergences are canceled. While the quadrupolar power asymmetry is small, it is conceptually important. Our calculation moreover clarifies how the predictions for this power asymmetry may change in models with different scalar-scalar-tensor bispectra, and shows that convincing detection of the quadrupolar power asymmetry would rule out the single-field slow-roll models of inflation.

A recent number of analyses of cosmological data have shown indications for the presence of extra radiation beyond the standard model at the equality and nucleosynthesis epochs, which has been usually interpreted as an effective number of neutrinos, $N_{\mathrm{eff}}>3.046$. In this work we establish the theoretical basis for a particle physics-motivated model (bound dark matter, BDM) which explains the need for extra radiation. The BDM model describes dark matter particles which are relativistic at a scale below $a<a_c$; these particles acquire mass with an initial velocity, $v_c$, at scales $a>a_c$ due to nonperturbative methods (as protons and neutrons do) and this process is described by a time-dependent equation of state, ${\omega }_{\mathrm{BDM}}(a)$. Owing to this behavior the amount of extra radiation changes as a function of the scale factor, and this implies that the extra relativistic degrees of freedom $N_{\mathrm{ex}}$ may also vary as a function of the scale factor. This is favored by data on the cosmic microwave background and big bang nucleosynthesis (BBN) epochs. We compute the range of values of the BDM model parameters, $x_c=a_c{v}_c$, that explain the values obtained for the ${}^4\mathrm{He}$ at BBN and $N_{\mathrm{eff}}$ at equality. Combining different analyses, we compute the values $x_c=4.13(\genfrac{}{}{0ex}{}{+3.65}{-4.13})\times {10}^{-5}$ and $v_c={0.37}_{-0.17}^{+0.18}$. We conclude that we can account for the apparent extra neutrino degrees of freedom $N_{\mathrm{ex}}$ using a phase transition in the dark matter with a time-dependent equation of state without introducing extra relativistic particles.

We explore the possibility of obtaining better constraints from future astronomical data by means of the Fisher information matrix formalism. In particular, we consider how cosmic microwave background (CMB) lensing information can improve our parameter error estimation. We consider a massive neutrino scenario and a time-evolving dark energy equation of state in the $\Lambda$ cold dark matter framework. We use Planck satellite experimental specifications together with the future galaxy survey Euclid in our forecast. We found improvements in almost all studied parameters considering Planck alone when CMB lensing information is used. In this case, the improvement with respect to the constraints found without using CMB lensing is of 93% around the fiducial value for the neutrino parameter. The improvement on one of the dark energy parameters reaches 4.4%. When Euclid information is included in the analysis, the improvements on the neutrino parameter constraint are of approximately 128% around its fiducial value. The addition of Euclid information provides smaller errors on the dark energy parameters as well. For Euclid alone, the figure of merit is a factor of $\sim 29$ higher than that from Planck alone even considering CMB lensing. Finally, the consideration of a nearly perfect CMB experiment showed that CMB lensing cannot be neglected, especially in more precise future CMB experiments, since it provided in our case a six-times-better figure of merit with respect to the unlensed CMB analysis.

We study the simplest renormalizable scalar leptoquark models where the standard model is augmented only by one additional scalar representation of $SU(3)\times SU(2)\times U(1)$. The requirement that there be no proton decay from renormalizable interactions singles out two such models, one of which exhibits an unusual top mass enhancement of the $\mu \to e\gamma$ decay rate. We analyze the phenomenology of the model with the unusual top mass enhancement of loop level chirality changing charged lepton processes in the light of existing and upcoming experiments. Both of the models that do not allow proton decay from renormalizable interactions have dimension-5 operators that, even if suppressed by the Planck scale, can give rise to an unacceptably high level of baryon number violation. We discuss symmetries that can forbid these dimension-5 operators.

We quantitatively examine the extent to which instanton degrees of freedom, contained within standard Monte-Carlo generated gauge-field configurations, can maintain the characteristic features of the mass and renormalization functions of the nonperturbative quark propagator. We use over-improved stout-link smearing to isolate instanton effects on the lattice. Using a variety of measures, we illustrate how gauge fields consisting almost solely of instantonlike objects are produced after only 50 sweeps of smearing. We find a full vacuum, with a packing fraction more than three times larger than phenomenological models predict. We calculate the overlap quark propagator on these smeared configurations, and find that even at high levels of smearing the majority of the characteristic features of the propagator are reproduced. We thus conclude that instantons contained within standard Monte-Carlo generated gauge-field configurations are the degrees of freedom responsible for the dynamical generation of mass observed in lattice QCD.

The heavy meson-antimeson pairs, where one is an excited $(\frac{3}{2}{)}^{+}$ meson and the other is a ground state $(\frac{1}{2}{)}^{-}$ meson, namely, the pairs ($D_1(2420)\overline{D}+\mathrm{c}.\mathrm{c}.$), ($D_1(2420){\overline{D}}^{*}+\mathrm{c}.\mathrm{c}.$), ($D_2(2460){\overline{D}}^{*}+\mathrm{c}.\mathrm{c}.$) in the charm sector and ($B_1(5721)\overline{B}+\mathrm{c}.\mathrm{c}.$), ($B_1(5721){\overline{B}}^{*}+\mathrm{c}.\mathrm{c}.$), ($B_2(5747){\overline{B}}^{*}+\mathrm{c}.\mathrm{c}.$) in the bottom sector, are allowed, by the quantum numbers, to be produced in the $S$ wave in $e^{+}{e}^{-}$ annihilation. We show, however, that such $S$-wave production is forbidden by the heavy quark spin symmetry. Thus, the yield of the considered meson pairs in $e^{+}{e}^{-}$ annihilation should be significantly suppressed near the respective thresholds. In our view, this substantially weakens the arguments for considering the $Y(4260)$ charmoniumlike resonance as a $D_1\overline{D}$ molecular state.

We present a derivation of an extended Nambu–Jona-Lasinio model with higher-order interactions departing from QCD by introducing a scalar auxiliary variable that reduces in the vacuum to the gluon condensate of order 2, $⟨A_{\mu }^a{A}_a^{\mu }⟩$. From a gap equation, we obtain a value for the condensate compatible with recent estimations from the lattice, $M_G\simeq 600\mathrm{MeV}$, simply using an UV cutoff. The gluon field and the auxiliary variable are integrated out, yielding a nonlinear effective model for quarks. By expanding the resulting effective model in powers of the quark field, we obtain fourth-order and eighth-order interactions, $(\overline{\psi }{\gamma }_{\mu }\psi \overline{\psi }{\gamma }^{\mu }\psi {)}^n$. Coupling constants are estimated as functions of the gluon condensate and of the cutoff.

We propose to use hard exclusive production of an exotic hadron for finding its internal quark-gluon configuration by the constituent-counting rule in perturbative QCD. In particular, the cross section for the exclusive process ${\pi }^{-}+p\to K^0+\Lambda (1405)$ is estimated at the scattering angle $\theta =90°$ in the center-of-mass frame by using current experimental data. In comparison, the cross section for the ground-state $\Lambda$ production ${\pi }^{-}+p\to K^0+\Lambda$ is also shown. We suggest that the internal quark configuration of $\Lambda (1405)$ should be determined by the asymptotic scaling behavior of the cross section. If it is an ordinary three-quark baryon, the scaling of the cross section is $s^{8}d\sigma /dt=\mathrm{\text{constant}}$, whereas it is $s^{10}d\sigma /dt=\mathrm{\text{constant}}$ if $\Lambda (1405)$ is a five-quark hadron, where $s$ and $t$ are Mandelstam variables. Such a measurement will be possible, for example, by using the high-momentum beam line at Japan Proton Accelerator Research Complex. In addition, another exclusive process $\gamma +p\to K^{+}+\Lambda (1405)$ could be investigated at laser electron photon beam line at SPring-8 and JLab for finding the nature of $\Lambda (1405)$. We indicate that the constituent-counting rule could be used as a valuable quantity in determining internal structure of exotic hadrons by high-energy exclusive processes, where quark-gluon degrees of freedom explicitly appear. Furthermore, it is interesting to investigate the transition from hadron degrees of freedom to quark-gluon ones for exclusive exotic-hadron production processes.

We report the results of a study of the exclusive semileptonic decays $B^{-}\to {\pi }^0{\ell }^{-}{\overline{\nu }}_{\ell }$, ${\overline{B}}^0\to {\pi }^{+}{\ell }^{-}{\overline{\nu }}_{\ell }$, $B^{-}\to {\rho }^0{\ell }^{-}{\overline{\nu }}_{\ell }$, ${\overline{B}}^0\to {\rho }^{+}{\ell }^{-}{\overline{\nu }}_{\ell }$ and $B^{-}\to \omega {\ell }^{-}{\overline{\nu }}_{\ell }$, where $\ell$ represents an electron or a muon. The events are tagged by fully reconstructing a second $B$ meson in the event in a hadronic decay mode. The measured branching fractions are $\mathcal{B}(B^{-}\to {\pi }^0{\ell }^{-}{\overline{\nu }}_{\ell })=(0.80\pm 0.08\pm 0.04)\times {10}^{-4}$, $\mathcal{B}({\overline{B}}^0\to {\pi }^{+}{\ell }^{-}{\overline{\nu }}_{\ell })=(1.49\pm 0.09\pm 0.07)\times {10}^{-4}$, $\mathcal{B}(B^{-}\to {\rho }^0{\ell }^{-}{\overline{\nu }}_{\ell })=(1.83\pm 0.10\pm 0.10)\times {10}^{-4}$, $\mathcal{B}({\overline{B}}^0\to {\rho }^{+}{\ell }^{-}{\overline{\nu }}_{\ell })=(3.22\pm 0.27\pm 0.24)\times {10}^{-4}$, and $\mathcal{B}(B^{-}\to \omega {\ell }^{-}{\overline{\nu }}_{\ell })=(1.07\pm 0.16\pm 0.07)\times {10}^{-4}$, where the first error is statistical and the second one is systematic. The obtained branching fractions are inclusive of soft photon emission. We also determine the branching fractions as a function of the 4-momentum transfer squared to the leptonic system $q^2=(p_{\ell }+p_{\nu }{)}^2$, where $p_{\ell }$ and $p_{\nu }$ are the lepton and neutrino 4-momenta, respectively. Using the pion modes, a recent light cone sum rule calculation, lattice QCD results and a model-independent description of the hadronic form factor, a value of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{ub}|=(3.52\pm 0.29)\times {10}^{-3}$ is extracted. A structure in the two-pion invariant mass distribution near $1.3\mathrm{GeV}/c^2$, which might be dominated by the decay $B^{-}\to f_2(1270){\ell }^{-}{\overline{\nu }}_{\ell }$, $f_2\to {\pi }^{+}{\pi }^{-}$, is seen. These results are obtained from a $711{\mathrm{fb}}^{-1}$ data sample that contains $772\times {10}^6$ $B\overline{B}$ pairs, collected near the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider.

The phase diagram and thermodynamic properties of the ($2+1$)-dimensional Gross–Neveu model are studied in the presence of a constant magnetic field. The optimized perturbation theory (OPT) is used to obtain results going beyond the large-$N$ approximation. The free energy and the complete phase diagram of the model, in terms of temperature, chemical potential, and magnetic field are obtained and studied in details. We find that some of the main qualitative changes induced by the OPT finite $N$ corrections concern the region of intermediate to high chemical potentials where this approximation adds a term proportional to $\lambda ⟨{\psi }^{+}\psi {⟩}^2/N$ to the free energy. Then, depending on the sign of $\lambda$ (relative to the critical coupling) and magnitude of the magnetic field, we observe a weakening (when $\lambda <0$) or enhancement (when $\lambda >0$) of the chiral broken region in the magnetized fermionic system. By comparing the results from the OPT and the large-$N$ approximation, we conclude that finite $N$ effects favor the phenomenon of inverse magnetic catalysis when the coupling constant is negative. We show that with the OPT the value of the coexistence chemical potential at vanishing temperature tends to decrease for large values of the magnetic field. This is opposite to what is seen in the large-$N$ approximation, where for large magnetic fields the coexistence chemical potential starts again to increase. Likewise, at finite temperature, the value of the chemical potential at the tricritical point also decreases with the magnetic field in the OPT case. Consequently, the shape of the phase diagrams predicted by the OPT and by the large-$N$ approximation look very different in the presence of high magnetic fields. Finally, for small values of magnetic field and temperature, we identify the presence of possible intermediate nonchiral phase transitions when varying the chemical potential. We show that these phenomena are not an artifact of the large-$N$ approximation and that they also occur within the OPT framework. These intermediate transitions are interpreted to be a consequence of the de Haas–van Alphen oscillations. We also explain why this type of phenomenon can happen in general for negative couplings but not for positive couplings.

The future apparent horizon of a black hole develops large stress energy due to quantum effects, unless the outgoing modes are in a thermal density matrix at the local Hawking temperature. It is shown for generic pure states that the deviation from thermality is so small that infalling observers will see no drama on their way to the stretched horizon, providing a derivation of black hole complementarity after the Page time. Atypical pure states, and atypical observers, may of course see surprises, but that is not surprising.

Since three-loop and higher-loop terms in the $\beta$ function of a gauge theory are scheme-dependent, one can, at least for sufficiently small coupling, carry out a scheme transformation that removes these terms. A basic question concerns the extent to which this can be done at an infrared fixed point of an asymptotically free gauge theory. This is important for quantitative analyses of the scheme dependence of such a fixed point. Here we study a scheme transformation $S_{R,m}$ with $m\ge 2$ that is constructed so as to remove the terms in the beta function at loop order $\ell =3$ to $\ell =m+1$, inclusive. Starting from an arbitrary initial scheme, we present general expressions for the coefficients of terms of loop order $\ell$ in the beta function in the transformed scheme from $\ell =m+2$ up to $\ell =8$. Extending a previous study of $S_{R,2}$, we investigate the range of applicability of the $S_{R,3}$ scheme transformation in an asymptotically free $\mathrm{SU}(N_c)$ gauge theory with an infrared zero in $\beta$ depending on the number, $N_f$, of fermions in the theory. We show that this $S_{R,3}$ scheme transformation can only be applied self-consistently in a restricted range of $N_f$ with a correspondingly small value of infrared fixed-point coupling. We also study the effect of higher-loop terms on the beta function of a U(1) gauge theory.

The ATLAS and CMS Collaborations have recently published new limits on $CP$-conserving anomalous couplings from the $W\gamma$ and $Z\gamma$ production processes. We study the corresponding limits that can be placed on the $CP$-violating anomalous couplings ${\tilde{\kappa }}_{\gamma }$ and $h_{\gamma ,Z}^1$ at the LHC. We find that the process $pp\to W\gamma$ at 14 TeV can place the 95% C.L. limit $\mid {\tilde{\kappa }}_{\gamma }\mid \lesssim 0.05$ with $10{\mathrm{fb}}^{-1}$, which is comparable to the existing LHC bound on the $CP$-conserving anomalous couplings ${\kappa }_{\gamma }$. Similarly, the process $pp\to Z\gamma$ can place the 95% C.L. limits $\mid h_{\gamma }^1\mid \lesssim 20$ and $\mid h_Z^1\mid \lesssim 40$, respectively. None of these limits is derived from a truly $CP$-odd observable, so it is not possible to separate the effects of the $CP$-violating anomalous couplings from the rest.

We show bounds on five- and six-dimensional universal extra dimension (UED) models from the latest results of the Higgs searches at the LHC and from the electroweak precision data for the $S$ and $T$ parameters. We consider the minimal UED model in five dimensions and the ones in six dimensions, compactified on $T^2/Z_2$, $T^2/(Z_2\times Z_2^{\prime })$, $T^2/Z_4$, $S^2$, $S^2/Z_2$, the real projective plane, and the projective sphere. The highest possible ultraviolet cutoff scale for each UED model is evaluated from the electroweak vacuum stability by solving the renormalization group equation of the Higgs self-coupling. This scale turns out to be lower than the conventional one obtained from the perturbativity of the gauge coupling. The resultant 95% C.L. lower bounds on the first Kaluza–Klein scale from the LHC results and from the $S$, $T$ analysis are 600 and 700 GeV in the minimal UED model, while those in the six-dimensional UED models are 800–1300 GeV and 900–1500 GeV, respectively.

We show that mostly right-handed Dirac sneutrinos are a viable supersymmetric light dark matter candidate. While the Dirac sneutrino scatters with nuclei dominantly through the $Z$-boson exchange and is stringently constrained by the invisible decay width of the $Z$ boson, it is possible to realize a large enough cross section with the nucleon to account for possible signals observed at direct dark matter searches, such as CDMS II(Si) or CoGeNT. Even if the XENON100 limit is taken into account, a small part of the signal region for CDMS II(Si) events remains outside the region excluded by XENON100.

It is well known that in noncentral heavy ion collisions a transient strong magnetic field is generated in the direction perpendicular to the reaction plane. The maximal strength of this field is estimated to be $eB\sim m_{\pi }^2\sim 0.02{\mathrm{GeV}}^2$ at the Relativistic Heavy Ion Collider and $eB\sim 15m_{\pi }^2\sim 0.3{\mathrm{GeV}}^2$ at the LHC. We investigate the effects of a strong magnetic field on $B$ and $D$ mesons, focusing on the changes of the energy levels and the masses of the bound states. Using the color evaporation model we discuss the possible changes in the production of $J/\psi$ and ${\rm Y}$.