Recently Georgi argued that a hypothetical conformally invariant hidden sector weakly interacting with ordinary particles will have unusual manifestations at low energies in terms of effective degrees of freedom called unparticles. In this paper we consider Aharonov-Bohm type of interactions due to the vector unparticle coupled to elementary fermions. We have found that the quantum mechanical phase shift is path dependent.

Wave functions and form factors of vector mesons are investigated in the holographic dual model of quantum chromodynamics with oscillator-like infrared cutoff. We introduce wave functions conjugate to solutions of the 5D equation of motion and develop a formalism based on these wave functions, which are very similar to those of a quantum-mechanical oscillator. For the lowest bound state ($\rho$-meson), we show that, in this model, the basic elastic form factor exhibits the perfect vector meson dominance, i.e., it is given by the $\rho$-pole contribution alone. The electric radius of the $\rho$-meson is calculated, $⟨r_{\rho }^2{⟩}_C=0.655{\mathrm{fm}}^2$, which is larger than in the case of the hard-wall cutoff. The squared radii of higher excited states are found to increase logarithmically rather than linearly with the radial excitation number. We calculate the coupling constant $f_{\rho }$ and find that the experimental value is closer to that calculated in the hard-wall model.

We propose a new description of inclusive diffraction in deep inelastic scattering. The diffractive structure functions are expressed in the dipole picture and contain heavy-quark contributions. The dipole scattering amplitude, a saturation model fitted on inclusive deep inelastic scattering data, features a saturation scale $Q_s(x)$ larger than 1 GeV for $x={10}^{-5}$. The $q\overline{q}g$ contribution to the diffractive final state is modeled in such a way that both the large-$Q^2$ and small-$\beta$ limits are implemented. In the regime $x_{\mathbb{P}}<0.01$ in which saturation is expected to be relevant, we obtain a parameter-free description of the HERA data with ${\chi }^2/\mathrm{points}=1.2$.

We discuss the possibility to study oscillations of atmospheric neutrinos in the ATLAS experiment at CERN. Because of the large total detector mass, a significant number of events is expected, and during the shutdown phases of the LHC, reconstruction of these events will be possible with very good energy and angular resolutions, and with charge identification. We argue that 500 live days of neutrino running could be achieved, and that a total of $\sim 160$ contained ${\nu }_{\mu }$ events and $\sim 360$ upward going muons could be collected during this time. Despite the low statistics, the excellent detector resolution will allow for an unambiguous confirmation of atmospheric neutrino oscillations and for measurements of the leading oscillation parameters. Though our detailed simulations show that the sensitivity of ATLAS is worse than that of dedicated neutrino experiments, we demonstrate that more sophisticated detectors, e.g. at the ILC, could be highly competitive with upcoming superbeam experiments, and might even give indications for the mass hierarchy and for the value of ${\theta }_{13}$.

We have computed the blackbody radiation spectra in $\kappa$-Minkowski spacetime, using the quantum mechanical picture of massless scalar particles as well as an effective quantum field theory picture. The blackbody radiation depends on how the field theory (and thus how the $\kappa$-Poincaré algebra) handles the ordering effect of the noncommutative spacetime. In addition, there exists a natural momentum cutoff of the order $\kappa$, beyond which a new real mode takes its shape from a complex mode and the old real mode flows out to be a new complex mode. However, the new high momentum real mode should not be physical since its contributions to the blackbody radiation spoil the commutative limit.

In this paper we perform a detailed study of the masses and mixing of the single charmed scalar tetraquarks: $cq\overline{q}\overline{q}$. We also give a systematic analysis of these tetraquark states by weight diagrams, quantum numbers, and flavor wave functions. Tetraquark masses are calculated using four different fits. The following $\mathrm{SU}(3{)}_{\mathrm{F}}$ representations are discussed: ${\overline{15}}_S$, ${\overline{3}}_S$, $6_A$, and ${\overline{3}}_A$. We use the flavor-spin Glozman-Riska interaction Hamiltonian with SU(3) flavor symmetry breaking. There are 27 different tetraquarks composed of a charm quark $c$ and of the three light flavors $u$, $d$, $s$: 11 cryptoexotic $(3{\mathrm{D}}_s^{+},4{\mathrm{D}}^{+},4{\mathrm{D}}^0)$ and 16 explicit exotic states. We discuss ${\mathrm{D}}_s$ and its isospin partners in the same multiplet, as well as all the other four-quark states. Some explicit exotic states appear in the spectrum with the same masses as ${\mathrm{D}}_s^{+}(2632)$ in ${\overline{15}}_S$ and with the same masses as ${\mathrm{D}}_s^{+}(2317)$ in $6_A$ representation, which confirm the tetraquark nature of these states.

Cross correlation between the cosmic microwave background (CMB) and large-scale structure is a powerful probe of dark energy and gravity on the largest physical scales. We introduce a novel estimator, the CMB-velocity correlation, that has most of its power on large scales and that, at low redshift, delivers up to a factor of 2 higher signal-to-noise ratio than the recently detected CMB-dark matter density correlation expected from the integrated Sachs-Wolfe effect. We propose to use a combination of peculiar velocities measured from supernovae type Ia and kinetic Sunyaev-Zeldovich cluster surveys to reveal this signal and forecast dark energy constraints that can be achieved with future surveys. We stress that low redshift peculiar velocity measurements should be exploited with complementary deeper large-scale structure surveys for precision cosmology.

Even though chaotic inflation is one of the most popular inflation models for its simple dynamics and compelling resolutions to the initial condition problems, its realization in supergravity has been considered a challenging task. We discuss how chaotic inflation dominated by the $D$-term can be induced in supergravity, which would give a new perspective on the inflation model building in supergravity.

A relatively simple method of overcoming the standard quantum limit in the next generation Advanced LIGO gravitational-wave detector is considered. It is based on the quantum variational measurement with a single, short (a few tens of meters) filter cavity. Estimates show that this method allows one to reduce the radiation-pressure noise at low frequencies ($<100\mathrm{Hz}$) to the level comparable with or smaller than the low-frequency noises of nonquantum origin (mirrors’ suspension noise, mirrors’ thermal noise, seismic noise, and gravity gradients fluctuations).

We present an extended study of how the next-to-minimal supersymmetric model easily avoids fine-tuning in electroweak symmetry breaking for a SM-like light Higgs with mass in the vicinity of 100 GeV, as beautifully consistent with precision electroweak data, while escaping LEP constraints due to the dominance of $h\to aa$ decays with $m_a<2m_b$ so that $a\to {\tau }^{+}{\tau }^{-}$ or jets. The residual $\sim 10\%$ branching ratio for $h\to b\overline{b}$ explains perfectly the well-known LEP excess at $m_h\sim 100\mathrm{GeV}$. Details of model parameter correlations and requirements are discussed as a function $\tan \beta$. Comparisons of fine-tuning in the NMSSM to that in the MSSM are presented. We also discuss fine-tuning associated with scenarios in which the $a$ is essentially pure singlet, has mass $m_a>30\mathrm{GeV}$, and decays primarily to $\gamma \gamma$ leading to an $h\to aa\to 4\gamma$ Higgs signal.

We report on a precise computation of the topological charge distribution in the SU(3) Yang-Mills theory. It is carried out on the lattice with high statistics Monte Carlo simulations by employing the definition of the topological charge suggested by Neuberger’s fermions. We observe significant deviations from a Gaussian distribution. Our results disfavor the $\theta$ behavior of the vacuum energy predicted by dilute instanton models, while they are compatible with the expectation from the large $N_c$ expansion.

The broad $1^{--}$ resonant structure around 1.5 GeV observed in the $K^{+}{K}^{-}$ mass spectrum in $J/\psi \to K^{+}{K}^{-}{\pi }^0$ by BESII is interpreted as a composition of $\rho (1450)$ and $\rho (1700)$. A much larger $BR(J/\psi \to \rho (1450,1700){\pi }^0,\rho (1450,1700)\to {\pi }^{+}{\pi }^{-})$ is predicted. Various other tests are proposed.

In the context of modified theory of gravity [$f(R)$ gravity], we try to study the conditions needed for validity of the generalized second law.

In this paper, we propose a Kaluza-Klein approach to gravity in $\Delta =4+n_1+n_2+\dots$ dimensions, where $n_1,n_2,\dots$ are the dimensions of independent internal spaces. One is interested in the case where each internal metric depends on the four-dimensional coordinates by a conformal factor. If all these conformal factors depend on the four-dimensional coordinates through a common scalar function $\Psi$, the induced effective four-dimensional gravity theory turns out to be of general scalar-tensor type. One shows that, if there are at least two internal spaces, the theory is not ruled out by experimental tests on gravitation, even if there is no massive scalar-potential term in the effective four-dimensional Lagrangian (contrary to what happens if there is only one internal space, in which case $\omega$ is of order unity, whatever the dimension of this internal space).

We perform a nonperturbative sum over geometries in a $(2+1)$-dimensional quantum gravity model given in terms of causal dynamical triangulations. Inspired by the concept of triangulations of product type introduced previously, we impose an additional notion of order on the discrete, causal geometries. This simplifies the combinatorial problem of counting geometries just enough to enable us to calculate the transfer matrix between boundary states labeled by the area of the spatial universe, as well as the corresponding quantum Hamiltonian of the continuum theory. This is the first time in dimension larger than 2 that a Hamiltonian has been derived from such a model by mainly analytical means, and it opens the way for a better understanding of scaling and renormalization issues.

Many of the recent numerical simulations of binary black holes in vacuum adopt the moving puncture approach. This successful approach avoids the need to impose numerical excision of the black hole interior and is easy to implement. Here we wish to explore how well the same approach can be applied to moving black hole punctures in the presence of relativistic hydrodynamic matter. First, we evolve single black hole punctures in vacuum to calibrate our Baumgarte-Shapiro-Shibata-Nakamura implementation and to confirm that the numerical solution for the exterior spacetime is invariant to any junk (i.e., constraint-violating) initial data employed in the black hole interior. Then we focus on relativistic Bondi accretion onto a moving puncture Schwarzschild black hole as a numerical test bed for our high-resolution shock-capturing relativistic hydrodynamics scheme. We find that the hydrodynamical equations can be evolved successfully in the interior without imposing numerical excision. These results help motivate the adoption of the moving puncture approach to treat the binary black hole–neutron star problem using conformal thin-sandwich initial data.

We study the relation between the Hessian matrix of the Riemannian Regge action on a 4-simplex and linearized quantum gravity. We give an explicit formula for the Hessian as a function of the geometry, and show that it has a single zero mode. We then use a 3D lattice model to show that (i) the zero mode is a remnant of the continuum diffeomorphism invariance, and (ii) we recover the complete free graviton propagator in the continuum limit. The results help clarify the structure of the boundary state needed in the recent calculations of the graviton propagator in loop quantum gravity, and, in particular, its role in fixing the gauge.

A general analytic procedure is developed to deal with the Newtonian limit of $f(R)$ gravity. A discussion comparing the Newtonian and the post-Newtonian limit of these models is proposed in order to point out the differences between the two approaches. We calculate the post-Newtonian parameters of such theories without any redefinition of the degrees of freedom, in particular, without adopting some scalar fields and without any change from Jordan to Einstein frame. Considering the Taylor expansion of a generic $f(R)$ theory, it is possible to obtain general solutions in terms of the metric coefficients up to the third order of approximation. In particular, the solution relative to the $g_{tt}$ component gives a gravitational potential always corrected with respect to the Newtonian one of the linear theory $f(R)=R$. Furthermore, we show that the Birkhoff theorem is not a general result for $f(R)$ gravity since time-dependent evolution for spherically symmetric solutions can be achieved depending on the order of perturbations. Finally, we discuss the post-Minkowskian limit and the emergence of massive gravitational wave solutions.