High precision data of lepton angular distributions for ${\gamma }^{*}/Z$ production in $pp$ collisions at the LHC, covering broad ranges of dilepton transverse momenta ($q_T$) and rapidity ($y$), were recently reported. Strong $q_T$ dependencies were observed for several angular distribution coefficients, $A_i$, including $A_0-A_4$. Significant $y$ dependencies were also found for the coefficients $A_1$, $A_3$ and $A_4$, while $A_0$ and $A_2$ exhibit very weak rapidity dependence. Using an intuitive geometric picture, we show that the $q_T$ and $y$ dependencies of the angular distributions coefficients can be well described.

We propose two new analysis strategies for studying charm and beauty quarks at colliders. The first strategy is aimed at testing the kinematics of heavy-flavor quarks within an identified jet. Here, we use the SoftDrop jet-declustering algorithm to identify two subjets within a large-radius jet, using subjet flavor tagging to test the heavy-quark splitting functions of QCD. For subjets containing a $J/\psi$ or $\mathrm{\Upsilon }$, this declustering technique can also help probe the mechanism for quarkonium production. The second strategy is aimed at isolating heavy-flavor production from gluon splitting. Here, we introduce a new FlavorCone algorithm, which smoothly interpolates from well-separated heavy-quark jets to the gluon-splitting regime where jets overlap. Because of its excellent ability to identify charm and beauty hadrons, the LHCb detector is ideally suited to pursue these strategies, though similar measurements should also be possible at ATLAS and CMS. Together, these SoftDrop and FlavorCone studies should clarify a number of aspects of heavy-flavor physics at colliders, and provide crucial information needed to improve heavy-flavor modeling in parton-shower generators.

We consider $\mathcal{N}=2$ four dimensional field theories compactified on a two torus in the presence of a $U(1)$ magnetic field. We discuss the restrictions leading to theories with (2,2) supersymmetry or (0,2) supersymmetry in two dimensions. The field theories live on D5 branes wrapped on four cycles of Calabi-Yau 3-folds or 4-folds described as resolved ADE singularities or resolved conifold fibered over a two torus.

In this paper, we quantize superconformal $\sigma$ models defined by worldline supermultiplets. Two types of superconformal mechanics, with and without a De Alfaro Fubini Furlan (DFF) term, are considered. Without a DFF term (Calogero potential only), the supersymmetry is unbroken. The models with a DFF term correspond to deformed (if the Calogero potential is present) or undeformed oscillators. For these (un)deformed oscillators, the classical invariant superconformal algebra acts as a spectrum-generating algebra of the quantum theory. Besides the $osp(1|2)$ examples, we explicitly quantize the superconformally invariant worldline $\sigma$ models defined by the $\mathcal{N}=4$ (1, 4, 3) supermultiplet [with $D(2,1;\alpha )$ invariance, for $\alpha \ne 0,-1$] and by the $\mathcal{N}=2$ (2, 2, 0) supermultiplet [with two-dimensional target and $sl(2|1)$ invariance]. The parameter $\alpha$ is the scaling dimension of the (1, 4, 3) supermultiplet and, in the DFF case, has a direct interpretation as a vacuum energy. In the DFF case, for the $sl(2|1)$ models, the scaling dimension $\lambda$ is quantized (either $\lambda =\frac{1}{2}+\mathbb{Z}$ or $\lambda =\mathbb{Z}$). The ordinary two-dimensional oscillator is recovered, after imposing a superselection restriction, from the $\lambda =-\frac{1}{2}$ model. In particular, a single bosonic vacuum is selected. The spectrum of the unrestricted two-dimensional theory is decomposed into an infinite set of lowest-weight representations of $sl(2|1)$. Extra fermionic raising operators, not belonging to the original $sl(2|1)$ superalgebra, allow (for $\lambda =\frac{1}{2}+\mathbb{Z}$) to construct the whole spectrum from the two degenerate (one bosonic and one fermionic) vacua.

We study the properties and direct detection prospects of an as of yet neglected population of dark matter (DM) particles moving in orbits gravitationally bound to the Earth. This DM population is expected to form via scattering by nuclei in the Earth’s interior. We compute fluxes and nuclear recoil energy spectra expected at direct detection experiments for the new DM population considering detectors with and without directional sensitivity, and different types of target materials and DM-nucleon interactions. DM particles bound to the Earth manifest as a prominent rise in the low-energy part of the observed nuclear recoil energy spectrum. Ultra-low threshold energies of about 1 eV are needed to resolve this effect. Its shape is independent of the DM-nucleus scattering cross-section normalization.

The mass splitting between the quarkonium spin-singlet state $h$ ($J^{PC}=1^{+-}$) and the spin average of the quarkonium spin-triplet states $\chi$ ($J^{PC}=0^{++},1^{++},2^{++}$) is seen to be astonishingly small, not only in the charmonium and bottomonium cases where the relevant masses have been measured, but in positronium as well. We find, both in nonrelativistic quark models and in nonrelativistic quantum chromodynamics (NRQCD), that this hyperfine splitting is so small that it can be used as a test of the pure $Q\overline{Q}$ content of the states. We discuss the $2P$ states of charmonium in the vicinity of 3.9 GeV, where the putative exotics $X(3872)$ and $X(3915)$ have been seen and a new ${\chi }_{c0}(2P)$ candidate has been observed at Belle.

The exclusive photoproduction of the heavy vector mesons $J/\mathrm{\Psi }$ is investigated in the context of peripheral lead-lead collisions for the energies available at the LHC, $\sqrt{s}=2.76\mathrm{TeV}$ and $\sqrt{s}=5.02\mathrm{TeV}$. Using the light-cone color dipole formalism, the rapidity distribution was calculated in two centrality bins at 50%–70% and 70%–90% in order to evaluate its robustness in extrapolating down to a smaller impact parameter. A modified photon flux is introduced, without change in the photonuclear cross section in relation to the ultraperipheral (UPC) case. Results were obtained for the two regions analyzed, which presented a maximum difference of 27% in frontal rapidity for the two regions. Comparing the results for $\sqrt{s}=2.76\mathrm{TeV}$ and $\sqrt{s}=5.02\mathrm{TeV}$, an increase was verified of approximately half the one obtained in the ultraperipheral regime in the central rapidity region.

We discuss single-diffractive production of dijets. The cross section is calculated within the resolved Pomeron picture, for the first time in the $k_t$-factorization approach, neglecting transverse momentum of the Pomeron. We use Kimber-Martin-Ryskin unintegrated parton (gluon, quark, antiquark) distributions in both the proton as well as in the Pomeron or subleading Reggeon. The unintegrated parton distributions are calculated based on conventional mmht2014nlo parton distribution functions in the proton and H1 Collaboration diffractive parton distribution functions used previously in the analysis of diffractive structure function and dijets at HERA. For comparison, we present results of calculations performed within the collinear-factorization approach. Our results remain those obtained in the next-to-leading-order approach. The calculation is (must be) supplemented by the so-called gap survival factor, which may, in general, depend on kinematical variables. We try to describe the existing data from Tevatron and make detailed predictions for possible LHC measurements. Several differential distributions are calculated. The ${\overline{E}}_T$, $\overline{\eta }$ and $x_{\overline{p}}$ distributions are compared with the Tevatron data. A reasonable agreement is obtained for the first two distributions. The last one requires introducing a gap survival factor which depends on kinematical variables. We discuss how the phenomenological dependence on one kinematical variable may influence dependence on other variables such as ${\overline{E}}_T$ and $\overline{\eta }$. Several distributions for the LHC are shown.

In this work, we investigate decays of $B_s\to {\eta }_c\varphi$ and $B_s\to {\eta }_c{f}_0(980)$ in a theoretical framework. The calculation is based on the postulation that $f_0(980)$ and $f_0(500)$ are mixtures of pure quark states $\frac{1}{\sqrt{2}}(\overline{u}u+\overline{d}d)$ and $\overline{s}s$. The hadronic matrix elements for $B_s\to \varphi$ and $B_s\to f_0(980)$ are calculated in the light-front quark model and the important Wilson coefficient $a_2$ which is closely related to nonperturbative QCD is extracted. However, our numerical results indicate that no matter how the mixing parameter is adjusted to reconcile contributions of $f_0(980)$ and $f_0(500)$, one cannot make the theoretical prediction on $B_s\to {\eta }_c+{\pi }^{+}{\pi }^{-}$ to meet the data. Moreover, the new measurement of $\mathrm{BR}(B_s\to J/\psi +f_0(500))<1.7\times {10}^{-6}$ also negates the mixture scenario. Thus, we conclude that the recent data suggest that $f_0(980)$ is a four-quark state (tetraquark or $K\overline{K}$ molecule), at least the fraction of its pure quark constituents is small.

We study scalar and electromagnetic perturbations of a family of nonsingular nonrotating black hole spacetimes that are solutions in a large class of conformally invariant theories of gravity. The effective potential for scalar perturbations depends on the exact form of the scaling factor. Electromagnetic perturbations do not feel the scaling factor, and the corresponding quasinormal mode spectrum is the same as in the Schwarzschild metric. We find that these black hole metrics are stable under scalar and electromagnetic perturbations. Assuming that the quasinormal mode spectrum for scalar perturbations is not too different from that for gravitational perturbations, we can expect that the calculation of the quasinormal mode spectrum and the observation with gravitational wave detectors of quasinormal modes from astrophysical black holes can constrain the scaling factor and test these solutions.

In this work we analyze the gravitational wave signal from hypermassive neutron stars formed after the merger of binary neutron star systems, focusing on its spectral features. The gravitational wave signals are extracted from numerical relativity simulations of models already considered by De Pietri et al. [Phys. Rev. D 93, 064047 (2016)], Maione et al. [Classical Quantum Gravity 33, 175009 (2016)], and Feo et al. [Classical Quantum Gravity 34, 034001 (2017)], and allow us to study the effect of the total baryonic mass of such systems (from $2.4M_{\odot }$ to $3M_{\odot }$), the mass ratio (up to $q=0.77$), and the neutron star equation of state, in both equal and highly unequal mass binaries. We use the peaks we find in the gravitational spectrum as an independent test of already published hypotheses of their physical origin and empirical relations linking them with the characteristics of the merging neutron stars. In particular, we highlight the effects of the mass ratio, which in the past was often neglected. We also analyze the temporal evolution of the emission frequencies. Finally, we introduce a modern variant of Prony’s method to analyze the gravitational wave postmerger emission as a sum of complex exponentials, trying to overcome some drawbacks of both Fourier spectra and least-squares fitting. Overall, the spectral properties of the postmerger signal observed in our simulation are in agreement with those proposed by other groups. More specifically, we find that the analysis of Bauswein and Stergioulas [Phys. Rev. D 91, 124056 (2015)] is particularly effective for binaries with very low masses or with a small mass ratio and that the mechanical toy model of Takami et al. [Phys. Rev. D 91, 064001 (2015)] provides a comprehensive and accurate description of the early stages of the postmerger.

One major background in direct searches for weakly interacting massive particles (WIMPs) comes from the deposition of radon progeny on detector surfaces. A dangerous surface background is the ${}^{206}\mathrm{Pb}$ nuclear recoils produced by ${}^{210}\mathrm{Po}$ decays. In this paper, we report the first characterization of this background in liquid argon. The scintillation signal of low energy Pb recoils is measured to be highly quenched in argon, and we estimate that the 103 keV ${}^{206}\mathrm{Pb}$ recoil background will produce a signal equal to that of a $\sim 5\mathrm{keV}$ (30 keV) electron recoil (${}^{40}\mathrm{Ar}$ recoil). In addition, we demonstrate that this dangerous ${}^{210}\mathrm{Po}$ surface background can be suppressed, using pulse shape discrimination methods, by a factor of $\sim 100$ or higher, which can make argon dark matter detectors near background-free and enhance their potential for discovery of medium- and high-mass WIMPs. We also discuss the impact on other low background experiments.

In this paper, we combine the $\nu$-two-Higgs-doublet-model with the inverse seesaw mechanisms. In this model, the Yukawa couplings involving the sterile neutrinos and the exotic Higgs bosons can be of order 1 in the case of a large $\tan \beta$. We calculated the corrections to the $Z$-resonance parameters $R_{l_i}$, $A_{l_i}$, and $N_{\nu }$, together with the $l_1\to l_2\gamma$ branching ratios and the muon anomalous $g-2$. Compared with the current bounds and plans for the future colliders, we find that the corrections to the electroweak parameters can be constrained or discovered in much of the parameter space.

We provide a universal expression of cross sections for the exclusive vector meson production and deeply virtual Compton scattering (DVCS) in photon-proton and photon-nucleus interactions based on the geometric scaling phenomenon. The theoretical parametrization based on the scaling property depends only on the single variable ${\tau }_A=Q^2/Q_{\mathrm{sat}}^2$, where the saturation scale, $Q_{\mathrm{sat}}$, drives the energy dependence and the corresponding nuclear effects. This phenomenological result describes all available data from DESY-HERA for $\rho ,\varphi ,J/\psi$ production and DVCS measurements. A discussion is also carried out on the size of nuclear shadowing corrections on photon-nucleus interaction.

After having announced the statistically significant observation ($5.6\sigma$) of the new exotic $\pi K$ atom, the DIRAC experiment at the CERN proton synchrotron presents the measurement of the corresponding atom lifetime, based on the full $\pi K$ data sample: $\tau =(5.5_{-2.8}^{+5.0})\times {10}^{-15}\mathrm{s}$. By means of a precise relation ($\approx 1\%$) between atom lifetime and scattering length, the following value for the $S$-wave isospin-odd $\pi K$ scattering length $a_0^{-}=\frac{1}{3}(a_{1/2}-a_{3/2})$ has been derived: $|a_0^{-}|=(0.072_{-0.020}^{+0.031})M_{\pi }^{-1}$.

We propose an $N=1$ supersymmetric extension for a class of weakly nonlocal four-dimensional gravitational theories. The construction is done in the superspace where the off-shell supersymmetry is manifest. The tree-level perturbative unitarity is explicitly proved both in superfield formalism and in field components. For the minimal nonlocal supergravity the spectrum is the same as in the local theory and in particular it is ghost free. The supersymmetric extension of the nonlocal Starobinsky theory is found as a straightforward application of the formalism.

Bianchi attractors are near horizon geometries with homogeneous symmetries in spatial directions. We construct supersymmetric Bianchi attractors in $\mathcal{N}=2,d=4$, 5 gauged supergravity. In $d=4$, we consider gauged supergravity coupled to vector and hypermultiplets. In $d=5$, we consider gauged supergravity coupled to vector multiplets with a generic gauging of symmetries of the scalar manifold and the $U(1{)}_R$ gauging of the $R$-symmetry. Analyzing the gaugino conditions, we show that when the fermionic shifts do not vanish, there are no supersymmetric Bianchi attractors. This is analogous to the known condition that for maximally supersymmetric solutions, all of the fermionic shifts must vanish. When the central charge satisfies an extremization condition, some of the fermionic shifts vanish and supersymmetry requires that the symmetries of the scalar manifold are not gauged. This allows supersymmetric Bianchi attractors sourced by massless gauge fields and a cosmological constant. In five dimensions in the Bianchi I class, we show that the anisotropic ${\mathrm{AdS}}_3\times {\mathbb{R}}^2$ solution is $1/2$ BPS (Bogomol’nyi-Prasad-Sommerfield). We also construct a new class of $1/2$ BPS Bianchi III geometries labeled by the central charge. When the central charge takes a special value, the Bianchi III geometry reduces to the known ${\mathrm{AdS}}_3\times {\mathbb{H}}^2$ solution. For the Bianchi V and VII classes, the radial spinor breaks all of supersymmetry. We briefly discuss the conditions for possible massive supersymmetric Bianchi solutions by generalizing the matter content to include tensor, hypermultiplets, and a generic gauging on the $R$-symmetry.

We show how to construct correlators for the ${\mathrm{CFT}}_1$ which is dual to noncommutative ${\mathrm{AdS}}_2$ ($nc{\mathrm{AdS}}_2$). We do it explicitly for the example of the massless scalar field on Euclidean $nc{\mathrm{AdS}}_2$. $nc{\mathrm{AdS}}_2$ is the quantization of ${\mathrm{AdS}}_2$ that preserves all the isometries. It is described in terms of the unitary irreducible representations, more specifically discrete series representations, of $so(2,1)$. We write down symmetric differential representations for the discrete series and then map them to functions on the Moyal-Weyl plane. The Moyal-Weyl plane has a large distance limit which can be identified with the boundary of $nc{\mathrm{AdS}}_2$. Killing vectors can be constructed on $nc{\mathrm{AdS}}_2$ which reduce to the ${\mathrm{AdS}}_2$ Killing vectors near the boundary. We, therefore, conclude that $nc{\mathrm{AdS}}_2$ is asymptotically ${\mathrm{AdS}}_2$, and so the $\mathrm{AdS}/\mathrm{CFT}$ correspondence should apply. For the example of the massless scalar field on Euclidean $nc{\mathrm{AdS}}_2$, the on-shell action, and resulting two-point function for the boundary theory, are computed to leading order in the noncommutativity parameter. The computation is nontrivial because nonlocal interactions appear in the Moyal-Weyl description. Nevertheless, the result is remarkably simple and agrees with that of the commutative scalar field theory, up to a rescaling.

We explicitly calculate the disk-level $S$-matrix element of two closed string R-R and one open string NS vertex operators in RNS formalism. We show that the amplitude satisfies various duality Ward identities. In particular, when one of the R-R is zero form, the other one is two form, and the NS state is a gauge boson, the amplitude transforms under an S-duality Ward identity to the amplitude of one dilaton, one B-field, and one gauge boson, which has recently been calculated explicitly. We have also proposed a soft theorem for the disk-level scattering amplitude of an ar bitrary number of hard closed strings and one soft open string at the leading order of soft momentum, and we have shown that the above amplitude satisfies the soft theorem.

We use the Holevo information to estimate distinguishability of microstates of a black hole in anti-de Sitter space by measurements one can perform on a subregion of a Cauchy surface of the dual conformal field theory. We find that microstates are not distinguishable at all until the subregion reaches a certain size and that perfect distinguishability can be achieved before the subregion covers the entire Cauchy surface. We will compare our results with expectations from the entanglement wedge reconstruction, tensor network models, and the bit threads interpretation of the Ryu-Takayanagi formula.