The hybrid leptogenesis framework combining the type-I and type-II seesaw mechanisms for neutrino mass necessarily include scattering topologies involving both the scalar triplet and the right-handed neutrino. We demonstrate that a systematic inclusion of these mixed scatterings can significantly alter the evolution of the number densities exhibiting, up to a factor ten, deviation in the predicted asymmetry as demonstrated by our benchmark scenarios. We provide quantitative constraints on the degeneracy of the seesaw scales where the complete analysis becomes numerically significant, limiting the validity of leptogenesis being dominated by the lightest seesaw species only.

In this paper, we study scalar mediator induced nonstandard interactions (SNSIs) in the context of the ESSnuSB experiment. In particular, we study the capability of ESSnuSB to put bounds on the SNSI parameters and also study the impact of SNSIs in the measurement of the leptonic $CP$ phase ${\delta }_{CP}$. Existence of SNSIs modifies the neutrino mass matrix and this modification can be expressed in terms of three diagonal real parameters (${\eta }_{ee}$, ${\eta }_{\mu \mu }$, and ${\eta }_{\tau \tau }$) and three off-diagonal complex parameters (${\eta }_{e\mu }$, ${\eta }_{e\tau }$, and ${\eta }_{\mu \tau }$). Our study shows that the upper bounds on the parameters ${\eta }_{\mu \mu }$ and ${\eta }_{\tau \tau }$ depend upon how $\mathrm{\Delta }{m}_{31}^2$ is minimized in the theory. However, this is not the case when one tries to measure the impact of SNSIs on ${\delta }_{CP}$. Further, we show that the $CP$ sensitivity of ESSnuSB can be completely lost for certain values of ${\eta }_{ee}$ and ${\eta }_{\mu \tau }$ for which the appearance channel probability becomes independent of ${\delta }_{CP}$.

We study the phenomenology of the charged Higgs boson at future muon colliders. We investigate the pair production ${\mu }^{+}{\mu }^{-}\to H^{+}{H}^{-}$, the single production ${\mu }^{+}{\mu }^{-}\to W^{\pm }{H}^{\mp }$, as well as the vector boson fusion (VBF) $\{e^{+}{e}^{-},{\mu }^{+}{\mu }^{-}\}\to \nu \overline{\nu }{H}^{+}{H}^{-}$. We show that the neutral Higgs exchange diagrams in the muon collider case can lead to a significant boost in the cross sections through their Yukawa couplings. Our results for the muon collider are systematically compared to the corresponding ones at $e^{+}{e}^{-}$ machines. It is demonstrated that the VBF $e^{+}{e}^{-}\to \nu \overline{\nu }{H}^{+}{H}^{-}$ can compete with the mentioned $2\to 2$ processes. We select benchmark points and perform signal-background analyses, taking into account detector simulations. We demonstrate the discovery region at $5\sigma$ and the excluded region at $2\sigma$ levels at a 3 TeV muon collider.

We present the first calculation of the pion gluon moment from lattice QCD in the continuum-physical limit. The calculation is done using clover fermions for the valence action with three pion masses, 220, 310 and 690 MeV, and three lattice spacings, 0.09, 0.12, and 0.15 fm, using ensembles generated by MILC Collaboration with $2+1+1$ flavors of highly improved staggered quarks (HISQ). On the lattice, we nonperturbatively renormalize the gluon operator in RI/MOM scheme using the cluster-decomposition error reduction (CDER) technique to enhance the signal-to-noise ratio of the renormalization constant. We extrapolate the pion gluon moment to the continuum-physical limit and obtain $⟨x{⟩}_g=0.394(58{)}_{\mathrm{stat}+\mathrm{NPR}}(39{)}_{\text{mixing}}$ in the $\overline{\mathrm{MS}}$ scheme at 2 GeV, with first error being the statistical error and uncertainties in nonperturbative renormalization, and the second being a systematic uncertainty estimating the effect of ignoring quark mixing. Our pion gluon momentum fraction has a central value lower than two recent single-ensemble lattice-QCD results near physical pion mass but is consistent with the recent global fits by JAM and xFitter and with most QCD-model estimates.

We propose an ansatz quantum circuit for the variational quantum eigensolver (VQE), suitable for exploring the phase structure of the multiflavor Schwinger model in the presence of a chemical potential. Our ansatz is capable of incorporating relevant model symmetries via constrains on the parameters, and can be implemented on circuit-based as well as measurement-based quantum devices. We show via classical simulation of the VQE that our ansatz is able to capture the phase structure of the model, and can approximate the ground state to a high level of accuracy. Moreover, we perform proof-of-principle simulations on superconducting, gate-based quantum hardware. Our results show that our approach is suitable for current gate-based quantum devices, and can be readily implemented on measurement-based quantum devices once available.

We determine, by means of lattice QCD calculations, the local form factors describing the $B_s\to {\mu }^{+}{\mu }^{-}\gamma$ decay, in the so-called electroquenched approximation. For this analysis we make use of the gauge configurations produced by the ETM Collaboration with $N_f=2+1+1$ flavor of Wilson-Clover twisted-mass fermions at maximal twist. To obtain the $B_s$ meson form factors, we perform simulations for several heavy-strange meson masses $m_{H_s}$ in the range $m_{H_s}\in [m_{D_s},2m_{D_s}]$, and extrapolate to the physical $B_s$ meson point $m_{B_s}\simeq 5.367\mathrm{GeV}$ making use of the HQET scaling laws. We cover the region of large dimuon invariant masses $\sqrt{q^2}>4.16\mathrm{GeV}$, and use our results to determine the branching fraction for $B_s\to {\mu }^{+}{\mu }^{-}\gamma$, which has been recently measured by LHCb in the region $\sqrt{q^2}>4.9\mathrm{GeV}$. The largest contribution to the uncertainty in the partial branching fractions at values of $\sqrt{q^2}<4.8\mathrm{GeV}$ is now due to resonance and other long-distance effects, including those from “charming penguins,” which we estimate by summing over the contributions from the $J^P=1^{-}$ charmonium resonances.

It is shown that the nontrivial energy dependencies of $D\overline{D}$, $D{\overline{D}}^{*}$, and $D^{*}{\overline{D}}^{*}$ pair production cross sections in $e^{+}{e}^{-}$ annihilation are well described within the approach based on an account of the final-state interaction of produced particles. This statement is valid for the production of charged and neutral particles. Interaction of $D^{(*)}$ and ${\overline{D}}^{(*)}$ is taken into account using the effective potential method. Its applicability is based on the fact that for near-threshold resonance the characteristic width of peak in the wave function is much larger than the interaction radius. The transition amplitudes between all three channels play an important role in the description of cross sections. These transitions are possible since all channels have the same quantum numbers $J^{PC}=1^{--}$.

We propose a method to determine the effective potential of QCD from the gap equation by introducing the homotopy method between the solutions of the equation of motion. Via this method, the effective potential beyond the bare vertex approximation is obtained, which then generalizes the Cornwall-Jackiw-Tomboulis effective potential for the bilocal composite operators. Moreover, the extended effective potential is set to be a function of self-energy instead of the propagator, which is the key point for the potential to be bounded from below. We then investigate the extended effective potential in the cases of phase transition of the QCD vacuum with a small current quark mass, the first order phase transition of QCD at finite temperature, and high baryon chemical potential. In the former case, the effective potential shows as an inflection point at the critical mass where the multiple solutions of the Dyson-Schwinger equation (DSE) vanishes, which is consistent with that obtained by solving the DSE directly. For the latter case, the in-medium properties, such as the latent heat and the difference of trace anomaly, of QCD is obtained.

The central exclusive production of charged-hadron pairs in $pp$ collisions at a center-of-mass energy of 13 TeV is examined, based on data collected in a special high-${\beta }^{*}$ run of the LHC. The nonresonant continuum processes are studied with the invariant mass of the centrally produced two-pion system in the resonance-free region, $m_{{\pi }^{+}{\pi }^{-}}<0.7$ or $m_{{\pi }^{+}{\pi }^{-}}>1.8\mathrm{GeV}$. Differential cross sections as functions of the azimuthal angle between the surviving protons, squared exchanged four-momenta, and $m_{{\pi }^{+}{\pi }^{-}}$ are measured in a wide region of scattered proton transverse momenta, between 0.2 and 0.8 GeV, and for pion rapidities $|y|<2$. A rich structure of interactions related to double-pomeron exchange is observed. A parabolic minimum in the distribution of the two-proton azimuthal angle is observed for the first time. It can be interpreted as an effect of additional pomeron exchanges between the protons from the interference between the bare and the rescattered amplitudes. After model tuning, various physical quantities are determined that are related to the pomeron cross section, proton-pomeron and meson-pomeron form factors, pomeron trajectory and intercept, and coefficients of diffractive eigenstates of the proton.

A search for the single production of a vectorlike top partner ($T$) with mass greater than 1 TeV decaying into a $Z$ boson and a top quark is presented, using the full Run 2 dataset corresponding to $139{\mathrm{fb}}^{-1}$ of $pp$ collisions at $\sqrt{s}=13\mathrm{TeV}$, collected in 2015–2018 with the ATLAS detector at the Large Hadron Collider. The targeted final state is characterized by the presence of a pair of electrons or muons with opposite-sign charges which form a $Z$-boson candidate, as well as by the presence of $b$-tagged jets and forward jets. Events with exactly two or at least three leptons are categorized into two independently optimized analysis channels. No significant excess above the background expectation is observed and the results from the two channels are statistically combined to set exclusion limits at 95% confidence level on the masses and couplings of $T$. The results are interpreted in several benchmark scenarios to set limits on the mass and universal coupling strength ($\kappa$) of the vectorlike quark. For singlet $T$ quarks, $\kappa$ values between 0.22 and 0.64 are excluded for masses between 1000 and 1975 GeV. For $T$ quarks in the doublet scenario, where the production cross section is much lower, $\kappa$ values between 0.54 and 0.88 are excluded for masses between 1000 and 1425 GeV.

This paper presents a search for pair production of higgsinos, the supersymmetric partners of the Higgs bosons, in scenarios with gauge-mediated supersymmetry breaking. Each higgsino is assumed to decay into a Higgs boson and a nearly massless gravitino. The search targets events where each Higgs boson decays into $b\overline{b}$, leading to a reconstructed final state with at least three energetic $b$-jets and missing transverse momentum. Two complementary analysis channels are used, with each channel specifically targeting either low or high values of the higgsino mass. The low-mass (high-mass) channel exploits $126(139){\mathrm{fb}}^{-1}$ of $\sqrt{s}=13\mathrm{TeV}$ data collected by the ATLAS detector during Run 2 of the Large Hadron Collider. No significant excess above the Standard Model prediction is found. At 95% confidence level, masses between 130 GeV and 940 GeV are excluded for higgsinos decaying exclusively into Higgs bosons and gravitinos. Exclusion limits as a function of the higgsino decay branching ratio to a Higgs boson are also reported.

Searches for dark matter with liquid xenon time projection chamber experiments have traditionally focused on the region of the parameter space that is characteristic of weakly interacting massive particles, ranging from a few $\mathrm{GeV}/c^2$ to a few $\mathrm{TeV}/c^2$. Models of dark matter with a mass much heavier than this are well motivated by early production mechanisms different from the standard thermal freeze-out, but they have generally been less explored experimentally. In this work, we present a reanalysis of the first science run of the LZ experiment, with an exposure of $0.9\text{tonne}\times \mathrm{yr}$, to search for ultraheavy particle dark matter. The signal topology consists of multiple energy deposits in the active region of the detector forming a straight line, from which the velocity of the incoming particle can be reconstructed on an event-by-event basis. Zero events with this topology were observed after applying the data selection calibrated on a simulated sample of signal-like events. New experimental constraints are derived, which rule out previously unexplored regions of the dark matter parameter space of spin-independent interactions beyond a mass of ${10}^{17}\mathrm{GeV}/c^2$.

We analyze the one-loop quantum entanglement entropy in ten-dimensional type-II string theory using the orbifold method by analytically continuing in $N$ the genus-one partition function for string orbifolds on ${\mathbb{R}}^2/{\mathbb{Z}}_N$ conical spaces known for all odd integers $N>1$. We show that the tachyonic contributions to the orbifold partition function can be appropriately summed and analytically continued to an expression that is finite in the physical region $0<N\le 1$ resulting in a finite and calculable answer for the entanglement entropy. We discuss the implications of the finiteness of the entanglement entropy for the information paradox, quantum gravity, and holography.

Gravitational lensing effect is one of most significant observational probes to investigate compact dark matter/objects over a wide mass range. In this work, we first propose to derive the population information and the abundance of supermassive compact dark matter in the mass range $\sim {10}^5–{10}^7{M}_{\odot }$ from six millilensed $\gamma$-ray burst (GRB) candidates in 3000 Fermi GRB events using the hierarchical Bayesian inference method. We obtain that, for the mass range $\sim {10}^5–{10}^7{M}_{\odot }$, the abundance of supermassive compact dark matter is $f_{\mathrm{CO}}={10}^{-1.60}$ in the log-normal mass distribution scenario. This result is in obvious tension with some other observational constraints, e.g., ultrafaint dwarfs and dynamical friction. However, it also was argued that there is only one system in these six candidates that has been identified as a lensed GRB event with fairly high confidence. In this case, the tension would be significantly alleviated. Therefore, it would be an interesting clue for both the millilensed GRB identification and the formation mechanism of supermassive compact dark matter.

We are examining a newly discovered parametric family of backgrounds in massive type IIA supergravity that contains a warped ${\mathrm{AdS}}_5$ factor. This family is the dual gravity description of four-dimensional quivers with $\mathcal{N}=1$ supersymmetry. We are interested in the status of classical integrability in these theories, and we show that there exists a single choice of solutions that is special, while all other choices lead to nonintegrable quivers and chaotic string motion. By focusing on this special choice, we provide strong suggestive evidence for the integrability of the dual field theory based on analytic studies and extensive numerical analysis.

We consider string/M-theory reductions on a compact space $X=X^{\mathrm{loc}}\cup X^{\circ }$, where $X^{\mathrm{loc}}$ contains the singular locus and $X^{\circ }$ is its complement. For the resulting supergravity theories, we construct a suitable symmetry topological field theory (SymTFT) associated with the boundary $\partial X^{\mathrm{loc}}\coprod \partial X^{\circ }$. We propose that boundary conditions for different Bogomol’nyi-Prasad-Sommerfield branes wrapping the same boundary cycles must be correlated for the SymTFT to yield an absolute theory consistent with quantum gravity. Using heterotic/M-theory duality, this constraint can be translated into a field-theoretic statement, which restricts the global structure of $d\ge 7$, $\mathcal{N}=1$ supergravity theories to reproduce precisely the landscape of untwisted toroidal heterotic compactifications. Furthermore, for six-dimensional (2, 0) theories, we utilize a subtle interplay between gauged 0-, 2-, and 4-form symmetries to provide a bottom-up explanation of the correlated boundary conditions in K3 compactifications of type IIB.

We examine local physics in the presence of global variables: variables associated with the whole of the spacelike surfaces of a foliation. These could be the (pseudo)constants of nature and their conjugate times, but our statements are more general. Interactions between the local and the global (for example, dependence of the local action on global times dual to constants) degrades full space-time diffeomorphism invariance down to spatial diffeomorphism invariance, and so an extra degree of freedom appears. When these presumably primordial global interactions switch off, the local action recovers full invariance and so the usual two gravitons, but a legacy matter component is left over, bearing the extra degree of freedom. Under the assumption that the preferred foliation is geodesic, this component behaves like dark matter, except that 3 of its 4 local degrees of freedom are frozen, forcing its rest frame to coincide with the preferred foliation. The nonfrozen degree of freedom (the number density of the effective fluid) is the survivor of the extra “graviton” present in the initial theory and keeps memory of all the past global interactions that took place in a given location in the preferred foliation. Such “painted-on” dark matter is best distinguished from the conventional one in situations where the preferred frame would be preposterous if all 4 degrees of freedom of dark matter were available. We provide one example: an outflowing halo of legacy matter with exact escape speed at each point and a very specific profile, surrounding a condensed structure made of normal matter.

In this work, we explicitly construct the vacuum solution of Einstein’s equations with prescribed multipole moments. By observing the behavior of the multipole spacetime metric at small distances, we conjecture that for a sufficiently large multipole moment, there is a minimal size below which no object in nature can support such a moment. The examples we have investigated suggest that such minimal size scales as $(M_n{)}^{1/(n+1)}$ [instead of $(M_n/M{)}^{1/n}$], where $M$ is the mass and $M_n$ is the $n$th order multipole moment. With the metric of the “multipole spacetime,” we analyze the shape of black hole shadow for various multipole moments and discuss the prospects of constraining the moments from shadow observations. In addition, we discuss the shift of gravitational wave phase with respect to those of the Kerr spacetime, for a test particle moving around an object with this set of multipole moments. These phase shifts are required for the program of mapping out the spacetime multipole moments based on gravitational wave observations of extreme mass-ratio inspirals.

In most analytical studies of light ray propagation in curved spacetimes around a gravitating object surrounded by a medium, it is assumed that the medium is a cold nonmagnetized plasma. The distinctive feature of this environment is that the equations of motion of the rays are independent of the plasma velocity, which, however, is not the case in other media. In this paper, we consider the deflection of light rays propagating near a spherically symmetric gravitating object in a moving dispersive medium given by a general refractive index. The deflection is studied when the motion of the medium is defined either as a radially falling onto a gravitating object (e.g., black hole), or rotating in the equatorial plane. For both cases the deflection angles are obtained. These examples demonstrate that fully analytic expressions can be obtained if the Hamiltonian for the rays takes a rather general form as a polynomial in a given momentum component. The general expressions are further applied to three specific choices of refractive indices, and these cases are compared. Furthermore, the light rays propagating around a gravitating object surrounded by a generally moving medium are further studied as a small perturbation of the cold plasma model. The deflection angle formula is hence expressed as a sum of zeroth and first order components, where the zeroth order term corresponds to the known cold plasma case, and the first order correction can be interpreted as caused by small difference in the refractive index compared to the cold plasma. The results presented in this paper allow to describe the effects caused by the motion of a medium and thus go beyond cold nonmagnetized plasma model.

During a binary black hole merger, multiple intermediary marginally outer trapped tubes connect the initial pair of apparent horizons with the final (single) apparent horizon. The marginally outer trapped surfaces (MOTSs) that foliate these tubes can have complicated geometries as well as nonspherical topologies. In particular, toroidal MOTSs form inside both of the original black holes during the early stages of a head-on merger that starts from time-symmetric initial data [1]. We show that toroidal MOTSs also form in the maximal analytic extension of the Schwarzschild spacetime as Kruskal time advances from the $T=0$ moment of time symmetry. As for the merger simulations, they cross the Einstein-Rosen bridge and are tightly sandwiched between the apparent horizons in the two asymptotic regions at early times. This strongly suggests that their formation is a consequence of the initial conditions rather than merger physics. Finally, we consider MOTSs of spherical topology in the Kruskal-Szekeres slicing and study their properties. All of these are contained within the apparent horizon but some do not enclose the wormhole.