Exploration of the resonances $Z_c(3900)$ and $Z(4430)$ are performed by assuming that they are the ground state and first radial excitation of the same tetraquark with $J^P=1^{+}$. The mass and current coupling of the $Z_c(3900)$ and $Z(4430)$ states are calculated using the QCD two-point sum rule method by taking into account vacuum condensates up to eight dimensions. We investigate the vertices $Z_c{M}_h{M}_l$ and $Z{M}_h{M}_l$, with $M_h$ and $M_l$ being the heavy and light mesons and evaluate the strong couplings $g_{Z_c{M}_h{M}_l}$ and $g_{Z{M}_h{M}_l}$ using the QCD sum rule on the light cone. The extracted couplings allow us to find the partial width of the decays $Z_c(3900)\to J/\psi \pi$, ${\psi }^{\prime }\pi$, ${\eta }_c\rho$ and $Z(4430)\to {\psi }^{\prime }\pi$, $J/\psi \pi$, ${\eta }_c^{\prime }\rho$, ${\eta }_c\rho$, which may help in comprehensive investigation of these resonances. We compare the width of the decays of $Z_c(3900)$ and $Z(4430)$ resonances with available experimental data as well as existing theoretical predictions.

The choice of statistics for a quantum particle is almost always a discrete one: either bosonic or fermionic. Anyons are the exceptional case for which the statistics can take a range of intermediate values. Holography provides an opportunity to address the question of how the behavior of interacting anyons depends on the choice of statistics. In this paper, we analyze the spectrum of a strongly coupled, gapless fluid of anyons described holographically by the D3-D7’ model with alternative boundary conditions. We investigate how these alternative boundary conditions impact the instability of the gapless homogeneous phase toward the formation of spatial order. In addition, we also show that for a particular, limiting choice of the alternative boundary conditions, this holographic system can be interpreted as describing strongly coupled ($2+1$)-dimensional QED. In this case, the instability leads to a spontaneous, spatially modulated magnetic field.

We derive new black hole solutions in Einstein-Maxwell-axion-dilaton theory with a hyperscaling violation exponent. We then examine the corresponding anomalous transport exhibited by cuprate strange metals in the normal phase of high-temperature superconductors via gauge-gravity duality. Linear-temperature-dependence resistivity and quadratic-temperature-dependence inverse Hall angle can be achieved. In the high-temperature regime, the heat conductivity and Hall Lorenz ratio are proportional to the temperature. The Nernst signal first increases as temperature goes up, but it then decreases with increasing temperature in the high-temperature regime.

Light scalar fields can form gravitationally bound compact objects called boson stars. The profile of boson stars in the Newtonian limit is described by the Gross-Pitaevskii-Poisson equations. We present a semianalytic solution to these equations and construct the profile of boson stars formed by a noninteracting scalar field. Our solution is stable with respect to numerical errors and has accuracy better than ${10}^{-6}$ over the entire range.

In this work, we propose the modeling of static wormholes within the $f(R,T)$ extended theory of gravity perspective. We present some models of wormholes, which are constructed from different hypotheses for their matter content, i.e., different relations for their pressure components (radial and lateral) and different equations of state. The solutions obtained for the shape function of the wormholes obey the necessary metric conditions. They show a behavior similar to those found in previous references about wormholes, which also happens to our solutions for the energy density of such objects. We also apply the energy conditions for the wormholes’ physical content.

We study the evolution of photon polarization during the photon-axion conversion process with focusing on the magnetic field configuration dependence. Most previous studies have been carried out in a conventional model where a network of magnetic domains is considered and each domain has a constant magnetic field. We investigate a more general model where a network of domains is still assumed, but each domain has a helical magnetic field. We find that the asymptotic behavior does not depend on the configuration of magnetic fields. Remarkably, we analytically obtain the asymptotic values of the variance of polarization in the conventional model. When the helicity is small, we show that there appears the damped oscillating behavior in the early stage of evolution. Moreover, we see that the constraints on the axion coupling and the cosmological magnetic fields using polarization observations are affected by the magnetic field configuration. This is because the different transient behavior of polarization dynamics is caused by the different magnetic field configuration. Recently, [C. Wang and D. Lai, J. Cosmol. Astropart. Phys. 06 (2016) 006.] claimed that the photon-axion conversion in helical model behaves peculiarly. However, our helical model gives much closer predictions to the conventional discontinuous magnetic field configuration model.

Model-independent constraints on hadronic form factors, in particular those describing exclusive semileptonic decays, can be derived from the knowledge of field correlators calculated in perturbative QCD, using analyticity and unitarity. The location of poles corresponding to below-threshold resonances, i.e., stable states that cannot decay into a pair of hadrons from the crossed channel of the form factor, must be known a priori, and their effect, accounted for through the use of Blaschke factors, is to reduce the strength of the constraints in the semileptonic region. By contrast, above-threshold resonances appear as poles on unphysical Riemann sheets, and their presence does not affect the original model-independent constraints. We discuss the possibility that the above-threshold poles can provide indirect information on the form factors on the first Riemann sheet, either through information from their residues or by constraining the discontinuity function. The bounds on form factors can be improved by imposing, in an exact way, the additional information in the extremal problem. The semileptonic $K\to \pi \ell \nu$ and $D\to \pi \ell \nu$ decays are considered as illustrations.

Lattice QCD calculations with different staggered valence and sea quarks can be used to improve determinations of quark masses, Gasser-Leutwyler couplings, and other parameters relevant to phenomenology. We calculate the masses and decay constants of flavored pions and kaons through next-to-leading order in staggered-valence, staggered-sea mixed-action chiral perturbation theory. We present the results in the valence-valence and valence-sea sectors, for all tastes. As in unmixed theories, the taste-pseudoscalar, valence-valence mesons are exact Goldstone bosons in the chiral limit, at nonzero lattice spacing. The results reduce correctly when the valence and sea quark actions are identical, connect smoothly to the continuum limit, and provide a way to control light quark and gluon discretization errors in lattice calculations performed with different staggered actions for the valence and sea quarks.

We show that quasi-parton distribution functions (quasi-PDFs) may be treated as hybrids of PDFs and primordial rest-frame momentum distributions of partons. This results in a complicated convolution nature of quasi-PDFs that necessitates using large $p_3\gtrsim 3\mathrm{GeV}$ momenta to get reasonably close to the PDF limit. As an alternative approach, we propose using pseudo-PDFs $\mathcal{P}(x,z_3^2)$ that generalize the light-front PDFs onto spacelike intervals and are related to Ioffe-time distributions $\mathcal{M}(\nu ,z_3^2)$, the functions of the Ioffe time $\nu =p_3{z}_3$ and the distance parameter $z_3^2$ with respect to which it displays perturbative evolution for small $z_3$. In this form, one may divide out the $z_3^2$ dependence coming from the primordial rest-frame distribution and from the problematic factor due to lattice renormalization of the gauge link. The $\nu$ dependence remains intact and determines the shape of PDFs.

A continuum approach to the kaon and pion bound-state problems is used to reveal their electromagnetic structure. For both systems, when used with parton distribution amplitudes appropriate to the scale of the experiment, Standard Model hard-scattering formulas are accurate to within 25% at momentum transfers $Q^2\approx 8{\mathrm{GeV}}^2$. There are measurable differences between the distribution of strange and normal matter within the kaons, e.g. the ratio of their separate contributions reaches a peak value of 1.5 at $Q^2\approx 6{\mathrm{GeV}}^2$. Its subsequent $Q^2$ evolution is accurately described by the hard scattering formulas. Projections for the ratio of kaon and pion form factors at timelike momenta beyond the resonance region are also presented. These results and projections should prove useful in planning next-generation experiments.

The role of the hard Pomeron (HP) exchanges in the high-energy diffractive interaction of nucleons is explored. It is demonstrated that the HP subdominance at available energies and low transferred momenta are due to the extremely low slope of its Regge trajectory.

In this long overdue second installment, we continue to develop the conformal bootstrap program for $\mathcal{N}=4$ superconformal field theories (SCFTs) in four dimensions via an analysis of the correlation function of four stress-tensor supermultiplets. We review analytic results for this correlator and make contact with the SCFT/chiral algebra correspondence of Beem et al. [Commun. Math. Phys. 336, 1359 (2015)]. We demonstrate that the constraints of unitarity and crossing symmetry require the central charge $c$ to be greater than or equal to $3/4$ in any interacting $\mathcal{N}=4$ SCFT. We apply numerical bootstrap methods to derive upper bounds on scaling dimensions and operator product expansion coefficients for several low-lying, unprotected operators as a function of the central charge. We interpret our bounds in the context of $\mathcal{N}=4$ super Yang-Mills theories, formulating a series of conjectures regarding the embedding of the conformal manifold—parametrized by the complexified gauge coupling—into the space of scaling dimensions and operator product expansion coefficients. Our conjectures assign a distinguished role to points on the conformal manifold that are self-dual under a subgroup of the $S$-duality group. This paper contains a more detailed exposition of a number of results previously reported in Beem et al. [Phys. Rev. Lett. 111, 071601 (2013)] in addition to new results.

The thermal contribution to the chiral vortical effect is believed to be related to the axial anomaly in external gravitational fields. We use the universality of the spin-gravity interaction to extend this idea to a wider set of phenomena. We consider the Kubo formula at weak coupling for the spin current of a vector field and derive a novel anomalous effect caused by the medium rotation: the chiral vortical effect for bosons. The effect consists in a spin current of vector bosons along the angular velocity of the medium. We argue that it has the same anomalous nature as in the fermionic case and show that this effect provides a mechanism for helicity transfer, from flow helicity to magnetic helicity.

We study gravitational lensing by a class of zero Ricci scalar wormholes which arise as solutions in a scalar-tensor theory of gravity. An attempt is made to find a possible link between lensing features, stable/unstable photon orbits and the energy conditions on the matter required to support these spacetimes. Our analysis shows (for this class of wormholes) that light rays always exhibit a positive deflection if the energy conditions are satisfied (nonexotic matter content). In contrast, if the energy conditions are violated (exotic matter), the net deflection of a light ray may be positive, negative or even zero, depending on values of the metric and impact parameters. This prompts us to introduce a surface defined by a turning point value at which the net deflection of a light ray is equal to zero, even though we have a curved spacetime geometry. We argue that the existence of such a surface may be linked to exotic/energy condition violating matter. Wormholes in modified gravity with matter satisfying the energy conditions do not seem to have such a zero deflection surface. Finally, we study strong gravitational lensing briefly and also look into the formation of Einstein and relativistic Einstein rings. We conclude with some estimates on the wormhole mass, throat-radius and the detectability of the Einstein rings.

We propose a new class of inflationary models in which inflation takes place while the inflaton is climbing up a potential hill due to a coupling to gravity. We study their attractor behavior, and investigate its relation with known attractors. We also discuss a possible realization of this type of models with natural inflation, and show that the inflationary predictions come well within the region consistent with the observation of the cosmic microwave background.

Hydroxide catalysis bonds are used in the aLIGO gravitational wave detectors and are an essential technology within the mirror suspensions that allowed detector sensitivities to be reached, which enabled the first direct detections of gravitational waves. Methods aimed at further improving hydroxide catalysis bonds for future upgrades to these detectors, in order to increase detection rates and the number of detectable sources, are explored. Also, the effect on the bonds of an aLIGO suspension construction procedure involving heat, the fiber welding process, is investigated. Here we show that thermal treatments can be beneficial to improving some of the bond properties important to the mirror suspensions in interferometric gravitational wave detectors. It was found that heat treating bonds at $150°\mathrm{C}$ increases bond strength by a factor of approximately 1.5 and a combination of bond aging and heat treatment of the optics at $150°\mathrm{C}$ reduces the mechanical loss of a bond from 0.10 to 0.05. It is also shown that current construction procedures do not reduce bond strength.

Using the data on the decay $D_s^{+}\to f_0(980){\pi }^{+}\to K^{+}{K}^{-}{\pi }^{+}$, we estimate the amplitude of the process $D_s^{+}\to [f_0(980)\to (K^{+}{K}^{-}+K^0{\overline{K}}^0)\to a_0^0(980)]{\pi }^{+}\to \eta {\pi }^0{\pi }^{+}$, caused by the mixing of $a_0^0(980)$ and $f_0(980)$ resonances that breaks the isotopic invariance due to the $K^{+}$ and $K^0$ meson mass difference. Effects of the interference of this amplitude with the amplitudes of the main mechanisms responsible for the decay $D_s^{+}\to \eta {\pi }^0{\pi }^{+}$ are analyzed. As such mechanisms, we examine the transition $D_s^{+}\to \eta {\rho }^{+}\to \eta {\pi }^0{\pi }^{+}$, which is observed in experiment, and the possible transition $D_s^{+}\to (a_0^0(980){\pi }^{+}+a_0^{+}(980){\pi }^0)\to \eta {\pi }^0{\pi }^{+}$. It is shown that the rapidly varying phase of the $a_0^0(980)-f_0(980)$ transition amplitude strongly influences the interference curves.

The latest measurement of the ratio of branching ratios $R_D=\mathcal{B}(B\to D\tau \nu )/\mathcal{B}(B\to Dl\nu )$ and $R_{D^{*}}=\mathcal{B}(B\to D^{*}\tau \nu )/\mathcal{B}(B\to D^{*}l\nu )$, where $l$ is either an electron or muon, differs from the standard model expectation by $1.9\sigma$ and $3.3\sigma$, respectively. Similar tension has been observed in purely leptonic $B\to \tau \nu$ decays as well. In this context, we consider an effective field theory formalism in the presence of new physics to explore various new physics couplings. Motivated by the recently proposed new observables $R_D^{\tau }=R_D/\mathcal{B}(B\to \tau \nu )$ and $R_{D^{*}}^{\tau }=R_{D^{*}}/\mathcal{B}(B\to \tau \nu )$, we impose $2\sigma$ constraints from $R_D^{\tau }$ and $R_{D^{*}}^{\tau }$ in addition to the constraints from $R_D$, $R_{D^{*}}$, and $\mathcal{B}(B\to \tau \nu )$ to constrain the new physics parameter space. We study the impact of new physics on various observables related to $B_s\to (D_s,D_s^{*})\tau \nu$ and $B\to \pi \tau \nu$ decay processes.

The planned upgrade of the CMS detector for the High Luminosity LHC allows us to find tracks in the silicon tracker for every single LHC collision and use them in the first level (hardware) trigger decision. So far, studies by CMS collaboration concentrated on the maintaining the overall trigger performance in the punishing pile up environment. We argue that the potential capabilities of the track trigger are much wider, and may offer groundbreaking opportunities for new physics searches. As an example, and to facilitate community discussion, we use a simple toy simulation to study rare Higgs decays into new particles with lifetime of order of a few mm.