Inspired by the present experimental status of charmed-strange mesons, we perform a systematic study of the charmed-strange meson family in which we calculate the mass spectra of the charmed-strange meson family by taking a screening effect into account in the Godfrey-Isgur model and investigate the corresponding strong decays via the quark pair creation model. These phenomenological analyses of charmed-strange mesons not only shed light on the features of the observed charmed-strange states, but also provide important information on future experimental search for the missing higher radial and orbital excitations in the charmed-strange meson family, which will be a valuable task in LHCb, the forthcoming Belle II, and PANDA.

We derive two relations involving spin polarizabilities of a spin-$1/2$ particle and consider their empirical implications for the proton. Using the empirical values of the proton anomalous magnetic moment, electric and magnetic charge radii, moments of the spin structure functions $g_1$, $g_2$, and of two spin polarizabilities, the present relations constrain the low-momentum behavior of generalized polarizabilities appearing in virtual Compton scattering. In the case of the proton, the dispersive model evaluations of the spin and generalized polarizabilities appear to be consistent with these relations. The ongoing measurements of different electromagnetic observables at the MAMI, Jefferson Lab, and $\mathrm{HI}\gamma \mathrm{S}$ facilities may be able to put these relations to a test, or use them to unravel the low-energy spin structure of the nucleon.

We perform a measurement of the $\tau \to l\gamma \nu \overline{\nu }$ ($l=e,\mu$) branching fractions for a minimum photon energy of 10 MeV in the $\tau$ rest frame, using $431{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ collisions collected at the center-of-mass energy of the $\mathrm{\Upsilon }(4S)$ resonance with the BABAR detector at the PEP-II storage rings. We find $\mathcal{B}(\tau \to \mu \gamma \nu \overline{\nu })=(3.69\pm 0.03\pm 0.10)\times 10^{-3}$ and $\mathcal{B}(\tau \to e\gamma \nu \overline{\nu })=(1.847\pm 0.015\pm 0.052)\times 10^{-2}$, where the first quoted error is statistical and the second is systematic. These results are substantially more precise than previous measurements.

In a scheme originally proposed by Gell-Mann, and subsequently shown to be realized at the $\mathrm{SU}(3)\times \mathrm{U}(1)$ stationary point of maximal gauged SO(8) supergravity by Warner and one of the present authors, the 48 spin-$\frac{1}{2}$ fermions of the theory remaining after the removal of eight Goldstinos can be identified with the 48 quarks and leptons (including right-chiral neutrinos) of the Standard model, provided one identifies the residual SU(3) with the diagonal subgroup of the color group $\mathrm{SU}(3{)}_c$ and a family symmetry $\mathrm{SU}(3{)}_f$. However, there remained a systematic mismatch in the electric charges by a spurion charge of $\pm \frac{1}{6}$. We here identify the “missing” U(1) that rectifies this mismatch, and that takes a surprisingly simple, though unexpected form.

We consider the electromagnetic field in the presence of polarizable point dipoles. In the corresponding effective Maxwell equation these dipoles are described by three dimensional delta function potentials. We review the approaches handling these: the self-adjoint extension, regularization/renormalization and the zero range potential methods. Their close interrelations are discussed in detail and compared with the electrostatic approach which drops the contributions from the self fields. For a homogeneous two dimensional lattice of dipoles we write down the complete solutions, which allow, for example, for an easy numerical treatment of the scattering of the electromagnetic field on the lattice or for investigating plasmons. Using these formulas, we consider the limiting case of vanishing lattice spacing, i.e., the transition to a continuous sheet. For a scalar field and for the TE polarization of the electromagnetic field this transition is smooth and results in the results known from the continuous sheet. Especially for the TE polarization, we reproduce the results known from the hydrodynamic model describing a two dimensional electron gas. For the TM polarization, for polarizability parallel and perpendicular to the lattice, in both cases, the transition is singular. For the parallel polarizability this is surprising and different from the hydrodynamic model. For perpendicular polarizability this is what was known in literature. We also investigate the case when the transition is done with dipoles described by smeared delta function, i.e., keeping a regularization. Here, for TM polarization for parallel polarizability, when subsequently doing the limit of vanishing lattice spacing, we reproduce the result known from the hydrodynamic model. In case of perpendicular polarizability we need an additional renormalization to reproduce the result obtained previously by stepping back from the dipole approximation.

We investigate the sources of the Hubble-induced mass for a flat direction in supersymmetric theories and show that the sign of the Hubble-induced mass generally changes just after the end of inflation. This implies that global cosmic strings generally form after the end of inflation in a wide class of supersymmetric models, including the minimal supersymmetric Standard Model. The cosmic strings emit gravitational waves whose frequency corresponds to the Hubble scale, until they disappear when the Hubble parameter decreases down to the soft mass of the flat direction. As a result, the peak frequency of gravitational waves is related to the supersymmetric scale. The observation of this gravitational wave signal, in conjunction with results from collider experiments and dark matter searches, can yield information of supersymmetry-breaking parameters.

We present a comprehensive derivation of linear perturbation equations for different matter species, including photons, baryons, cold dark matter, scalar fields, and massless and massive neutrinos in the presence of a generic conformal coupling. Starting from the Lagrangians, we show how the conformal transformation affects the dynamics. In particular, we discuss how to incorporate consistently the scalar coupling in the equations of the Boltzmann hierarchy for massive neutrinos and the subsequent fluid approximations. We use the recently proposed K-mouflage model as an example to demonstrate the numerical implementation of our linear perturbation equations. K-mouflage is a new mechanism to suppress the fifth force between matter particles induced by the scalar coupling, but in the linear regime the fifth force is unsuppressed and can change the clustering of different matter species in different ways. We show how the cosmic microwave background, lensing potential and matter power spectra are affected by the fifth force and find ranges of K-mouflage parameters whose effects could be seen observationally. We also find that the scalar coupling can have the nontrivial effect of shifting the amplitude of the power spectra of the lensing potential and density fluctuations in opposite directions, although both probe the overall clustering of matter. This paper can serve as a reference for those who work on generic coupled scalar field cosmology or those who are interested in the cosmological behavior of the K-mouflage model.

The gravitational waveforms in the ghost-free bigravity theory exhibit deviations from those in general relativity. The main difference is caused by graviton oscillations in the bigravity theory. We investigate the prospects for the detection of the corrections to gravitational waveforms from coalescing compact binaries due to graviton oscillations and for constraining bigravity parameters with the gravitational wave observations. We consider the bigravity model discussed by the De Felice-Nakamura-Tanaka subset of the bigravity model, and the phenomenological model in which the bigravity parameters are treated as independent variables. In both models, the bigravity waveform shows strong amplitude modulation, and there can be a characteristic frequency of the largest peak of the amplitude, which depends on the bigravity parameters. We show that there is a detectable region of the bigravity parameters for the advanced ground-based laser interferometers, such as Advanced LIGO, Advanced Virgo, and KAGRA. This region corresponds to the effective graviton mass of $\mu \gtrsim {10}^{-17}{\mathrm{cm}}^{-1}$ for $\tilde{c}-1\gtrsim {10}^{-19}$ in the phenomenological model, while $\mu \gtrsim {10}^{-16.5}{\mathrm{cm}}^{-1}$ for $\kappa {\xi }_c^2\gtrsim {10}^{0.5}$ in the De Felice-Nakamura-Tanaka subset of the bigravity model, respectively, where $\tilde{c}$ is the propagation speed of the massive graviton and $\kappa {\xi }_c^2$ corresponds to the corrections to the gravitational constant in general relativity. These regions are not excluded by existing solar system tests. We also show that, in the case of $1.4-1.4M_{\odot }$ binaries at the distance of 200 Mpc, $\log {\mu }^2$ is determined with an accuracy of $\mathcal{O}(0.1)\%$ at the $1\sigma$ level for a fiducial model with ${\mu }^2=10^{-33}{\mathrm{cm}}^{-2}$ in the case of the phenomenological model.

The vector boson fusion (VBF) topology at the Large Hadron Collider at 14 TeV provides an opportunity to search for new physics. A feasibility study for the search of sleptons in a compressed mass spectra scenario is presented in the final state of two jets, one or two low $p_T$ nonresonant leptons, and missing energy. The presence of the VBF tagged jets and missing energy are effective in reducing standard model backgrounds. Using smuon production with a mass difference between ${\tilde{l}}_L$ and ${\tilde{\chi }}_1^0$ of 5–15 GeV, the significance of observing the signal events is found to be $\sim 3–6\sigma$ for $m_{\tilde{l}}=115–135\mathrm{GeV}$, considering an integrated luminosity of $3000{\mathrm{fb}}^{-1}$.

We present the first direct lattice calculation of the isovector sea-quark distributions in the nucleon within the framework of the large-momentum effective field theory proposed recently. We use $N_f=2+1+1$ highly improved staggered quarks lattice gauge ensembles (generated by the MILC Collaboration) and clover valence fermions with pion mass 310 MeV. We establish the convergence of the result as the nucleon momentum increases within the uncertainty of the calculation. Although the lattice systematics are not yet fully under control, we obtain some qualitative features of the flavor structure of the nucleon sea: $\overline{d}(x)>\overline{u}(x)$ leading to the violation of the Gottfried sum rule, $\mathrm{\Delta }\overline{u}(x)>\mathrm{\Delta }\overline{d}(x)$ as indicated by the STAR data at large and small leptonic pseudorapidity.

Motivated by the Son-Yamamoto (SY) relation, which connects the three-point and two-point correlators, we consider the holographic renormalization group (RG) flows in the bottom-up approach to holographic QCD via the Hamilton-Jacobi equation with respect to the radial coordinate. It is shown that the SY relation is diagonal with respect to the RG flow in the 5D Yang-Mills-Chern-Simons model, while the RG equation acquires an inhomogeneous term in the model with an additional scalar field, which encodes the chiral condensate.

The free fermionic construction of the heterotic string in four dimensions produced a large space of three-generation models with the underlying $SO(10)$ embedding of the Standard Model states. The $SO(10)$ symmetry is broken to a subgroup directly at the string scale. Over the past few years free fermionic models with the Pati-Salam and flipped $SU(5)$ subgroups have been classified. In this paper we extend this classification program to models in which the $SO(10)$ symmetry is broken at the string level to the $SU(4)\times SU(2{)}_L\times U(1{)}_R$ (SU421) subgroup. The subspace of free fermionic models that we consider corresponds to symmetric ${\mathbb{Z}}_2\times {\mathbb{Z}}_2$ orbifolds. We provide a general argument that shows that this class of SU421 free fermionic models cannot produce viable three-generation models.

The scattering of neutrinos assuming a “secret” interaction at low energy is considered. To leading order in energy, the two-body potential is a $\delta$-potential, and it is used as a motivation to study generic short-range elastic interactions between neutrinos. The scattering cross section and Sommerfeld enhancement depend on two phenomenological parameters deriving from the exact form of the potential, akin to “renormalized” coupling constants. Repulsive potentials lead to a decrease in the total cross section, resulting in an enhancement of the neutrino density. For attractive potentials of the right form, substantial Sommerfeld enhancement can appear.

We investigate the leptonic decay constants of the pion and its excitations with a 5-d holographic model for quantum chromodynamics. We prove numerically that the leptonic decay constants of the excited states of the pion vanish in the chiral limit when chiral symmetry is dynamically broken. This nontrivial result is in agreement with a solid prediction of quantum chromodynamics and is based on a generalized Gell-Mann–Oakes–Renner relationship involving the decay constants and masses of the excited states of the pion. We also obtain an extended partially conserved axial-vector current relation that includes the fields of the excited states of the pion, a relation that was proposed long ago in the context of current algebra.

In realistic situations, black hole spacetimes do not admit a global timelike Killing vector field. However, it is possible to describe the horizon in a quasilocal setting by introducing the notion of a quasilocal boundary with certain properties which mimic the properties of a black hole inner boundary. Isolated horizons and Killing horizons are examples of such a kind. In this paper, we construct such a boundary of spacetime which is null and admits a conformal Killing vector field. Furthermore we construct the space of solutions (in general relativity) which admits such quasilocal conformal Killing boundaries. We also establish a form of the first law for these quasilocal horizons.

We investigate the role played by large diffeomorphisms of quantum isolated horizons for the statistics of loop quantum gravity (LQG) black holes by means of their relation to the braid group. To this aim the symmetries of Chern-Simons theory are recapitulated with particular regard to the aforementioned type of diffeomorphisms. For the punctured spherical horizon, these are elements of the mapping class group of $S^2$, which is almost isomorphic to a corresponding braid group on this particular manifold. The mutual exchange of quantum entities in two dimensions is achieved by the braid group, rendering the statistics anyonic. With this we argue that the quantum isolated horizon model of LQG based on $SU(2{)}_k$-Chern-Simons theory exhibits non-Abelian anyonic statistics. In this way a connection to the theory behind the fractional quantum Hall effect and that of topological quantum computation is established, where non-Abelian anyons play a significant role.

We propose the modified form of the conventional holographic conserved charges which provides us the frame-independent expressions for charges. This form is also shown to be independent of the holographic renormalization scheme. We show the frame and scheme independence through the matching of our holographic expression to the covariant bulk expression of conserved charges. As an explicit example, we consider five-dimensional Anti-de Sitter Kerr black holes and show that our form of holographic conserved charges gives us the identical expressions in the rotating and nonrotating frames.

We discuss the problem of defining a preferred vacuum state at a given time for a quantized scalar field in Friedmann, Lemaître, Robertson, Walker space-time. Among the infinitely many homogeneous, isotropic vacua available in the theory, we show that there exists at most one for which every Fourier mode makes a vanishing contribution to the adiabatically renormalized energy-momentum tensor at any given instant. For massive fields such a state exists in the most commonly used backgrounds in cosmology and, within the adiabatic regularization scheme, provides a natural candidate for the “ground state” at that instant of time. The extension to the massless and the conformally coupled case are also discussed.

Continuing our analytic computation of the first-order self-force contribution to Detweiler’s redshift variable we provide the exact expressions of the ninth and ninth-and-a-half post-Newtonian terms.