We investigate the possible size of $h\to bs$ in two-Higgs-doublet models with generic Yukawa couplings. Even though the corresponding rates are in general expected to be small due to the indirect constraints from $B_s\to {\mu }^{+}{\mu }^{-}$ and $B_s–{\overline{B}}_s$ mixing, we find regions in parameter space where $h\to bs$ can have a sizable branching ratio well above 10%. This requires a tuning of the neutral scalar masses and their couplings to muons, but then all additional constraints such as $B\to X_s\gamma$, $(g-2{)}_{\mu }$, and $h\to {\mu }^{+}{\mu }^{-}$ are satisfied. In this case, $h\to bs$ can be a relevant background in $h\to b\overline{b}$ searches and vice versa due to the imperfect $b$-tagging purity. Furthermore, if $h\to bs$ is sizeable, one expects two more scalar resonances in the proximity of $m_h$. We briefly comment on other flavor-violating Higgs decays and on the 95 GeV $\gamma \gamma$ resonance within generic two-Higgs-doublet models.

We perform a model independent analysis of new physics in $B_s^{*}\to {\mu }^{+}{\mu }^{-}$ decay. We intend to identify new physics operator(s) which can provide large enhancement in the branching ratio of $B_s^{*}\to {\mu }^{+}{\mu }^{-}$ above its standard model prediction. For this, we consider new physics in the form of vector, axial-vector, scalar and pseudoscalar operators. We find that scalar and pseudoscalar operators do not contribute to the branching ratio of $B_s^{*}\to {\mu }^{+}{\mu }^{-}$. We perform a global fit to all relevant $b\to s{\mu }^{+}{\mu }^{-}$ data for different new physics scenarios. For each of these scenarios, we predict $\mathrm{Br}(B_s^{*}\to {\mu }^{+}{\mu }^{-})$. We find that a significant enhancement in $\mathrm{Br}(B_s^{*}\to {\mu }^{+}{\mu }^{-})$ is not allowed by any of these new physics operators. In fact, for all new physics scenarios providing a good fit to the data, the branching ratio of $B_s^{*}\to {\mu }^{+}{\mu }^{-}$ is suppressed as compared to the standard model (SM) value. Hence the present $b\to s{\mu }^{+}{\mu }^{-}$ data indicates that the future measurement of $\mathrm{Br}(B_s^{*}\to {\mu }^{+}{\mu }^{-})$ is expected to be suppressed in comparison to the standard model prediction.

In supersymmetric models with scalar sequestering, superconformal strong dynamics in the hidden sector suppresses the low-energy couplings of mass dimension 2, compared to the squares of the dimension-1 parameters. Taking into account restrictions on the anomalous dimensions in superconformal theories, I point out that the interplay between the hidden and visible sector renormalizations gives rise to quasifixed point running for the supersymmetric Standard Model squared mass parameters, rather than driving them to 0. The extent to which this dynamics can ameliorate the little hierarchy problem in supersymmetry is studied. Models of this type in which the gaugino masses do not unify are arguably more natural, and are certainly more likely to be accessible, eventually, to the Large Hadron Collider.

We describe a procedure for extracting momentum derivatives of nucleon matrix elements on the lattice directly at $Q^2=0$. This is based on the Rome method for computing momentum derivatives of quark propagators. We apply this procedure to extract the nucleon isovector magnetic moment and charge radius as well as the isovector induced pseudoscalar form factor at $Q^2=0$ and the axial radius. For comparison, we also determine these quantities with the traditional approach of computing the corresponding form factors, i.e. $G_E^v(Q^2)$ and $G_M^v(Q^2)$ for the case of the vector current and $G_P^v(Q^2)$ and $G_A^v(Q^2)$ for the axial current, at multiple $Q^2$ values followed by $z$-expansion fits. We perform our calculations at the physical pion mass using a 2HEX-smeared Wilson-clover action. To control the effects of excited-state contamination, the calculations were done at three source-sink separations and the summation method was used. The derivative method produces results consistent with those from the traditional approach but with larger statistical uncertainties especially for the isovector charge and axial radii.

Recently, we have shown that the $X(3872)$ state can be naturally generated as a bound state by incorporating the hadron interactions into the Godfrey-Isgur quark model using a Friedrichs-like model combined with the quark pair creation model, in which the wave function for the $X(3872)$ as a combination of the bare $c\overline{c}$ state and the continuum states can also be obtained. Under this scheme, we now investigate the isospin-breaking effect of $X(3872)$ in its decays to $J/\psi {\pi }^{+}{\pi }^{-}$ and $J/\psi {\pi }^{+}{\pi }^{-}{\pi }^0$. By coupling its dominant continuum parts to $J/\psi \rho$ and $J/\psi \omega$ through the quark rearrangement process, one could obtain the reasonable ratio of $\mathcal{B}(X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}{\pi }^0)/\mathcal{B}(X(3872)\to J/\psi {\pi }^{+}{\pi }^{-})\simeq (0.58–0.92)$. It is also shown that the $\overline{D}{D}^{*}$ invariant mass distributions in the $B\to \overline{D}{D}^{*}K$ decays could be understood qualitatively at the same time. This scheme may provide more insight into the enigmatic nature of the $X(3872)$ state.

In previous work, we have commenced the task of unpacking the 473 800 776 reflexive polyhedra by Kreuzer and Skarke into a database of Calabi-Yau threefolds [R. Altman et al. J. High Energy Phys. 02 (2015) 158.] (see www.rossealtman.com). In this paper, following a pedagogical introduction, we present a new algorithm to isolate Swiss cheese solutions characterized by “holes,” or small 4-cycles, descending from the toric divisors inherent to the original four dimensional reflexive polyhedra. Implementing these methods, we find 2268 explicit Swiss cheese manifolds, over half of which have $h^{1,1}=6$. Many of our solutions have multiple large cycles. Such Swiss cheese geometries facilitate moduli stabilization in string compactifications and provide flat directions for cosmological inflation.

We study the “anti-Unruh effect” for an entangled quantum state in reference to the counterintuitive cooling previously pointed out for an accelerated detector coupled to the vacuum. We show that quantum entanglement for an initially entangled (spacelike separated) bipartite state can be increased when either a detector attached to one particle is accelerated or both detectors attached to the two particles are in simultaneous accelerations. However, if the two particles (e.g. detectors for the bipartite system) are not initially entangled, entanglement cannot be created by the anti-Unruh effect. Thus, within a certain parameter regime, this work shows that the anti-Unruh effect can be viewed as an amplification mechanism for quantum entanglement.

Directional detection is an important way to detect dark matter. An input for these experiments is the dark matter velocity distribution. Recent hydrodynamical simulations have shown that the dark matter velocity distribution differs substantially from the Standard Halo Model. We study the impact of some of these updated velocity distributions in dark matter directional detection experiments. We calculate the ratio of events required to confirm the forward-backward asymmetry and the existence of the ring of maximum recoil rate using different dark matter velocity distributions for ${}^{19}\mathrm{F}$ and Xe targets. We show that with the use of updated dark matter velocity profiles, the forward-backward asymmetry and the ring of maximum recoil rate can be confirmed using a factor of $\sim 2–3$ less events when compared to that using the Standard Halo Model.

We investigate a class of universes in which the weak interaction is not in operation. We consider how astrophysical processes are altered in the absence of weak forces, including big bang nucleosynthesis (BBN), galaxy formation, molecular cloud assembly, star formation, and stellar evolution. Without weak interactions, neutrons no longer decay, and the universe emerges from its early epochs with a mixture of protons, neutrons, deuterium, and helium. The baryon-to-photon ratio must be smaller than the canonical value in our Universe to allow free nucleons to survive the BBN epoch without being incorporated into heavier nuclei. At later times, the free neutrons readily combine with protons to make deuterium in sufficiently dense parts of the interstellar medium, and provide a power source before they are incorporated into stars. Almost all of the neutrons are incorporated into deuterium nuclei before stars are formed. As a result, stellar evolution proceeds primarily through strong interactions, with deuterium first burning into helium, and then helium fusing into carbon. Low-mass deuterium-burning stars can be long-lived, and higher-mass stars can synthesize the heavier elements necessary for life. Although somewhat different from our own, such universes remain potentially habitable.

In order to improve the theoretical prediction of the electron anomalous magnetic moment $a_e$ we have carried out a new numerical evaluation of the 389 integrals of Set V, which represent 6,354 Feynman vertex diagrams without lepton loops. During this work, we found that one of the integrals, called $X024$, was given a wrong value in the previous calculation due to an incorrect assignment of integration variables. The correction of this error causes a shift of $-1.26$ to the Set V contribution, and hence to the tenth-order universal (i.e., mass-independent) term $A_1^{(10)}$. The previous evaluation of all other 388 integrals is free from errors and consistent with the new evaluation. Combining the new and the old (excluding $X024$) calculations statistically, we obtain $7.606(192)(\alpha /\pi {)}^5$ as the best estimate of the Set V contribution. Including the contribution of the diagrams with fermion loops, the improved tenth-order universal term becomes $A_1^{(10)}=6.675(192)$. Adding hadronic and electroweak contributions leads to the theoretical prediction $a_e(\text{theory})=1159652182.032(720)\times {10}^{-12}$. From this and the best measurement of $a_e$, we obtain the inverse fine-structure constant ${\alpha }^{-1}(a_e)=137.0359991491(331)$. The theoretical prediction of the muon anomalous magnetic moment is also affected by the update of QED contribution and the new value of $\alpha$, but the shift is much smaller than the theoretical uncertainty.

We explore whether a tree-level expression for the gluon two-point function, supposed to express effects of an horizon term introduced to eliminate the Gribov ambiguity, is consistent with the propagator obtained in simulations of lattice-regularized quantum chromodynamics (QCD). In doing so, we insist that the gluon two-point function obey constraints that ensure a minimal level of consistency with parton-like behavior on the ultraviolet domain. In consequence, we are led to a position which supports a conjecture that the gluon mass and horizon scale are equivalent emergent mass-scales, each with a value of roughly 0.5 GeV; and wherefrom it appears plausible that the dynamical generation of a running gluon mass may alone be sufficient to remove the Gribov ambiguity.

QCD constituent counting rules define the scaling behavior of exclusive hadronic scattering and electromagnetic scattering amplitudes at high momentum transfer in terms of the total number of fundamental constituents in the initial and final states participating in the hard subprocess. The scaling laws reflect the twist of the leading Fock state for each hadron and hence the leading operator that creates the composite state from the vacuum. Thus, the constituent counting scaling laws can be used to identify the twist of exotic hadronic candidates such as tetraquarks and pentaquarks. Effective field theories must consistently implement the scaling rules in order to be consistent with the fundamental theory. Here, we examine how one can apply constituent counting rules for the exclusive production of one or two neutral vector mesons $V^0$ in $e^{+}{e}^{-}$ annihilation, processes in which the $V^0$ can couple via intermediate photons. In the case of a (narrow) real $V^0$, the photon virtuality is fixed to a precise value $s_1=m_{V^0}^2$, thus treating the $V^0$ as a single fundamental particle. Each real $V^0$ thus contributes to the constituent counting rules with $N_{V_0}=1$. In effect, the leading operator underlying the $V^0$ has twist 1. Thus, in the specific physical case of single or double on-shell $V^0$ production via intermediate photons, the predicted scaling from counting rules coincides with vector-meson dominance (VMD), an effective theory that treats $V^0$ as an elementary field. However, the VMD prediction fails in the general case where the $V^0$ is not coupled through an elementary photon field, and then the leading-twist interpolating operator has twist $N_{V_0}=2$. Analogous effects appear in $pp$ scattering processes.

The production of heavy meson-antimeson pairs of the type $SV$ and $PA$ in $e^{+}{e}^{-}$ annihilation is considered, with $P$ and $V$ being the ground-state $J^P=0^{-}$ and $J^P=1^{-}$ (anti)mesons from the $(1/2{)}^{-}$ doublet and $S$ and $A$ standing for the excited $J^P=0^{+}$ and $J^P=1^{+}$ (anti)mesons from the $(1/2{)}^{+}$ doublet. It is argued that the production amplitudes in these two channels should be equal up to a higher (than one) order in the heavy quark mass (${\mathrm{\Lambda }}_{\mathrm{QCD}}/M_Q$) expansion, $A(e^{+}{e}^{-}\to S\overline{V})=A(e^{+}{e}^{-}\to A\overline{P})$, including both the $S$-wave and the $D$-wave amplitudes. Given that the $SV$ and $PA$ thresholds are extremely close, the production cross section in both channels should be the same to a high degree of accuracy. In practice, this behavior can be studied for the processes $e^{+}{e}^{-}\to D_{s0}(2317){\overline{D}}_s^{*}+\mathrm{c}.\mathrm{c}.$ and $e^{+}{e}^{-}\to D_{s1}(2460){\overline{D}}_s+\mathrm{c}.\mathrm{c}.$ in the charm sector and $e^{+}{e}^{-}\to B_{s0}{\overline{B}}_s^{*}+\mathrm{c}.\mathrm{c}.$ and $e^{+}{e}^{-}\to B_{s1}{\overline{B}}_s+\mathrm{c}.\mathrm{c}.$ in the $B$ sector.

Collective modes of an anisotropic hot QCD medium have been studied within the semiclassical transport theory employing the Bhatnagar-Gross-Krook (BGK) collisional kernel. The modeling of the isotropic medium is primarily based on a recent quasiparticle description of a hot QCD equation of state where the medium effects have been encoded in effective gluon and quark/antiquark momentum distributions that posses nontrivial energy dispersions. The anisotropic distribution functions are obtained in a straightforward way by stretching or squeezing the isotropic ones along one of the directions. The gluon self-energy is computed using these distribution functions in a linearized transport equation with the BGK collisional kernel. Further, the tensor decomposition of gluon self-energy leads to the structure functions which eventually controls the dispersion relations and the collective mode structure of the medium. It has been seen that both the medium effects and collisions induce appreciable modifications to the collective modes or the plasma excitations in the hot QCD medium.

Results are reported from a search for new physics in 13 TeV proton-proton collisions in the final state with large missing transverse momentum and two Higgs bosons decaying via $H\to b\overline{b}$. The search uses a data sample accumulated by the CMS experiment at the LHC in 2016, corresponding to an integrated luminosity of $35.9{\mathrm{fb}}^{-1}$. The search is motivated by models based on gauge-mediated supersymmetry breaking, which predict the electroweak production of a pair of Higgsinos, each of which can decay via a cascade process to a Higgs boson and an undetected lightest supersymmetric particle. The observed event yields in the signal regions are consistent with the standard model background expectation obtained from control regions in data. Higgsinos in the mass range 230–770 GeV are excluded at 95% confidence level in the context of a simplified model for the production and decay of approximately degenerate Higgsinos.

We study the greybody factors of the scalar fields in spherically symmetric Einstein-Gauss-Bonnet–de Sitter black holes in higher dimensions. We derive the greybody factors analytically for both minimally and nonminimally coupled scalar fields. Moreover, we discuss the dependence of the greybody factor on various parameters including the angular momentum number, the nonminimally coupling constant, the spacetime dimension, the cosmological constant, and the Gauss-Bonnet coefficient in detail. We find that the nonminimal coupling may suppress the greybody factor and the Gauss-Bonnet coupling could enhance it, but they both suppress the energy emission rate of Hawking radiation.

We investigate the behavior of low-mass, planar domain walls in the so-called ${\varphi }^4$ model of the scalar field on the Schwarzschild and Kerr backgrounds. We focus on a transit of a domain wall through a black hole and solve numerically the equations of motion for a range of parameters of the domain wall and the black hole. We observe a behavior resembling an occurrence of ringing modes. Perturbations of domain walls vanish during latter evolution, suggesting their stability against a passage through the black hole. The results obtained for Kerr and Reissner-Nordström black holes are also compared.

In this article we study the geodesic motion of test particles and light in the five-dimensional Myers-Perry-anti–de Sitter spacetime. We derive the equations of motion and present their solutions in terms of the Weierstrass $\wp$, $\sigma$, and $\zeta$ functions. With the help of parametric diagrams and effective potentials, we analyze the geodesic motion and give a list of all possible orbit types for timelike, null, and spacelike geodesics. We plot examples of the orbits and take a look at the photon region in five dimensions. Furthermore, we study spacelike geodesics and their relation to the AdS/CFT correspondence.

In this paper we reconsider the existence of stealth fields during the evolution of our Universe by admitting more realistic nonminimal couplings to gravity than the conformal one. In the framework of the FRW cosmology we found that inhomogeneous stealths, as those enabled in the conformal case, are only allowed in de Sitter backgrounds. In particular, it is shown that the homogeneous stealths resulting from nonconformal couplings can coexist with each kind of matter dominant in the several phases characterizing the evolution of our Universe according to the $\mathrm{\Lambda }\mathrm{CDM}$ model.