An extended superscaling analysis of quasielastic electron-scattering data is proposed by parametrizing the scaling function as the sum of a symmetric function corresponding to the emission of a single particle plus a contribution from the phase space of two-particle emission. The phase space of two-particle emission (2p2h) is multiplied by a $q$-dependent parameter that has been fitted to describe the tail behavior of the scaling function. This approach allows for an alternative description of the quasielastic electron scattering data, incorporating the contributions from both single-particle and two-particle emission processes induced by the one-body current and explaining the asymmetry of the scaling function. In a factorized schematic model based on the independent-pair approximation, the 2p2h parameter is related to the high-momentum distribution of the pair averaged over 2p2h excitations. However, in the phenomenological fitting approach undertaken here, this coefficient includes other contributions such as interference with two-body currents and effects of the final-state interactions. We present predictions for the inclusive two-nucleon emission cross section induced by electrons and neutrinos.

An amplitude analysis of ${\mathrm{\Lambda }}_c^{+}\to p{K}^{-}{\pi }^{+}$ decays together with a measurement of the ${\mathrm{\Lambda }}_c^{+}$ polarization vector in semiōleptonic beauty hadron decays is presented. A sample of 400 000 candidates is selected from proton-proton collisions recorded by the LHCb detector at a center-of-mass energy of 13 TeV. An amplitude model is developed and the resonance fractions as well as two- and three-body decay parameters are reported. The mass and width of the $\mathrm{\Lambda }(2000)$ state are also determined. A significant ${\mathrm{\Lambda }}_c^{+}$ polarization is found. A large sensitivity of the ${\mathrm{\Lambda }}_c^{+}\to p{K}^{-}{\pi }^{+}$ decay to the polarization is seen, making the amplitude model suitable for ${\mathrm{\Lambda }}_c^{+}$ polarization measurements in other systems.

A search for the baryon- and lepton-number violating decays $B^0\to p{\mu }^{-}$ and $B_s^0\to p{\mu }^{-}$ is performed at the LHCb experiment using data collected in proton-proton collisions at $\sqrt{s}=7$, 8 and 13 TeV, corresponding to integrated luminosities of 1, 2, and $6{\mathrm{fb}}^{-1}$, respectively. No significant signal for $B^0\to p{\mu }^{-}$ and $B_s^0\to p{\mu }^{-}$ decays is found and the upper limits on the branching fractions are determined to be $\mathcal{B}(B^0\to p{\mu }^{-})<2.6(3.1)\times {10}^{-9}$ and $\mathcal{B}(B_s^0\to p{\mu }^{-})<12.1(14.0)\times {10}^{-9}$, respectively, at 90% (95%) confidence level. These are the first limits on these decays to date.

Resonant structures in the dipion mass spectrum from ${\chi }_{c1}(3872)\to {\pi }^{+}{\pi }^{-}J/\psi$ decays, produced via $B^{+}\to K^{+}{\chi }_{c1}(3872)$ decays, are analyzed using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$. A sizeable contribution from the isospin conserving ${\chi }_{c1}(3872)\to \omega J/\psi$ decay is established for the first time, $(21.4\pm 2.3\pm 2.0)\%$, with a significance of more than $7.1\sigma$. The amplitude of isospin violating decay, ${\chi }_{c1}(3872)\to {\rho }^{0}J/\psi$, relative to isospin conserving decay, ${\chi }_{c1}(3872)\to \omega J/\psi$, is properly determined, and it is a factor of 6 larger than expected for a pure charmonium state.

We investigate the scalar absorption spectrum of wormhole solutions constructed via the recently developed thin-shell formalism for Palatini $f(\mathcal{R})$ gravity. Such wormholes come from the matching of two Reissner-Nordström spacetimes at a timelike hypersurface (shell), which, according to the junction conditions in Palatini $f(\mathcal{R})$, can be stable and have either positive or negative energy density. In particular, we identified a new physically interesting configuration made out of two overcharged Reissner-Nordström spacetimes, whose absorption profile departs from that of black holes and other previously considered wormholes in the whole range of frequencies. Unlike in symmetric wormhole solutions, the asymmetry of the effective potential causes the dilution of the resonances associated to the quasibound states for the high-frequency regime. Therefore, slight asymmetries in wormhole space-times could have a dramatic impact on the observable features associated to resonant states.

In this paper we build the general gravitational-lensing formalism for luminal Horndeski theories, deriving the Jacobi matrix equation and the general angular diameter distance in these theories through the screen-space formalism. We generalize the focusing and multiple-lensing theorems in General Relativity to include the luminal Horndeski theories and derive constraints they must satisfy to exhibit the same gravitional-lensing behavior in General Relativity. This provides a way to test theories through strong-lensing effects, as well as a full theoretical framework for testing lensing predictions in these theories against observations. We find that for some theories, like metric $f(R)$ and unified $k$-essence, the obtained theorems are satisified in general physical cases, while for others, like Galileon condensate models, the current observational constraints show the theory has the same gravitational-lensing behavior as in General Relativity.

We investigate the Schwarzschild-(anti) de Sitter spacetime with the anisotropic metric ansatz. The Wheeler-DeWitt equation for such a metric is solved numerically. In the presence of the cosmological constant $\mathrm{\Lambda }$, we show that two classical wave packets can be annihilated inside the black hole horizon, i.e., the annihilation-to-nothing scenario. It is interesting that the Wheeler-DeWitt equation can be extended to the asymptotic de Sitter spacetime outside the cosmological horizon. Surprisingly, the only bounded nontrivial wave function beyond the cosmological horizon satisfies the DeWitt boundary condition, i.e., the wave function must vanish at a certain finite radius. This might be an alternative explanation to the classicalization of quantum fluctuations in the de Sitter space, where this topic is also related to decoherence.

Perturbation theory is a powerful tool for studying large-scale structure formation in the universe and calculating observables such as the power spectrum or bispectrum. However, beyond linear order, typically this is done by assuming a simplification in the time-dependence of gravitational-coupling kernels between the matter and velocity fluctuations. Though the true dependencies are known for Lambda cold dark matter cosmologies, they are ignored due to the computational costs associated with considering them in full and, instead, are replaced by simpler dependencies valid for an Einstein–de Sitter cosmology. Here we develop, implement, and demonstrate the effectiveness of a new numerical method for finding the full dynamical evolution of these kernels to all perturbative orders based upon spectral methods using Chebyshev polynomials. This method is found to be orders of magnitude more efficient than direct numerical solvers while still producing highly accurate and reliable results. A code implementation of the Chebyshev spectral method is then presented and characterized. The code has been made publicly available alongside this paper. We expect our method to be of use for interpretation of upcoming galaxy clustering measurements.

An era of kination occurs when the Universe’s energy density is dominated by a fast-rolling scalar field. Dark matter that is thermally produced during an era of kination requires larger-than-canonical annihilation cross sections to generate the observed dark matter relic abundance. Furthermore, dark matter density perturbations that enter the horizon during an era of kination grow linearly with the scale factor prior to radiation domination. We show how the resulting enhancement to the small-scale matter power spectrum increases the microhalo abundance and boosts the dark matter annihilation rate. We then use gamma-ray observations to constrain thermal dark matter production during kination. The annihilation boost factor depends on the minimum halo mass, which is determined by the small-scale cutoff in the matter power spectrum. Therefore, observational limits on the dark matter annihilation rate imply a minimum cutoff scale for a given dark matter particle mass and kination scenario. For dark matter that was once in thermal equilibrium with the Standard Model, this constraint establishes a maximum allowed kinetic decoupling temperature for the dark matter. This bound on the decoupling temperature implies that the growth of perturbations during kination cannot appreciably boost the dark matter annihilation rate if dark matter was once in thermal equilibrium with the Standard Model.

The population of stellar-origin black hole binaries (SOBHBs) detected by existing ground-based gravitational-wave detectors is an exciting target for the future space-based Laser Interferometer Space Antenna (LISA). LISA is sensitive to signals at significantly lower frequencies than ground-based detectors. SOBHB signals will thus be detected much earlier in their evolution, years to decades before they merge. The mergers will then occur in the frequency band covered by ground-based detectors. Observing SOBHBs years before merger can help distinguish between progenitor models for these systems. We present a new Bayesian parameter estimation algorithm for LISA observations of SOBHBs that uses a time-frequency (wavelet) -based likelihood function. Our technique accelerates the analysis by several orders of magnitude compared to the standard frequency domain approach and allows for an efficient treatment of nonstationary noise.

Compact boson-star binaries are hypothetical sources for ground-based and space gravitational-wave detectors. Their signal would be a messenger for novel fundamental fields and could shed light on the dark matter. In this work, we further develop our analysis [Phys. Rev. D 102, 083002 (2020)], aimed at constraining the properties of these objects with future observations. We use a coherent waveform template for the inspiral stage of boson-star binaries with large quartic self-interactions, including tidal deformability and the nonlinear dependence of the quadrupole moments on the spin in terms of the fundamental couplings of the scalar field theory. Performing a Bayesian analysis, we investigate the ability of a third-generation gravitational-wave detector such as the Einstein Telescope to distinguish these exotic sources from black holes and infer constraints on the fundamental couplings of the model.

Using first-principles numerical simulations, we investigate the Casimir effect in zero-temperature SU(3) lattice gauge theory in $3+1$ spacetime dimensions. The Casimir interaction between perfect chromometallic mirrors reveals the presence of a new gluonic state with the mass $m_{\mathrm{gt}}=1.0(1)\sqrt{\sigma }=0.49(5)\mathrm{GeV}=0.29(3)M_{0^{++}}$, which is substantially lighter than the $0^{++}$ ground-state glueball. We call this excitation “glueton,” interpreting it as a nonperturbative colorless state of gluons bound to their negatively colored images in the chromometallic mirror. The glueton is a gluonic counterpart of a surface electron-hole exciton in semiconductors. We also show that a heavy quark is attracted to the neutral chromometallic mirror, thus supporting the existence of a “quarkiton” (a “quark exciton”) colorless state in QCD, which is formed by a single quark with its antiquark image in the chromometallic mirror. Analogies with edge modes in topological insulators and boundary states of fractional vortices in multicomponent condensates are highlighted.

In the present work, the mass spectra of the light mesons, the kaons ($u\overline{s}$), and strangeonium ($s\overline{s}$) is systematically studied within the framework of Regge phenomenology. Several relations between Regge slope, intercept, and meson masses are extracted with the assumption of linear Regge trajectories. Using these relations, the ground state masses ($1{}^1{S}_0$ and $1{}^3{S}_1$) of the pure $s\overline{s}$ states are evaluated. Further, the Regge slopes are extracted for kaons and strangeonium to obtain the orbitally excited state masses in the ($J,M^2$) plane. Similarly, the values of Regge parameters are calculated in the ($n,M^2$) plane for each Regge trajectory and we obtain the radially excited state masses of mesons lying on that Regge trajectory. We compared our obtained spectrum with the experimental observations where available and with the predictions of other theoretical approaches. Here, we predict the possible quantum numbers of several recently observed experimental states, which still require further verification, and also evaluate the higher orbital and radial excited states that may be detected in the near future. We expect our predicted results could provide valuable information for future experimental searches for missing excited kaons and strangeonium mesons.

In the light-front quark model (LFQM) amenable to the simultaneous study of both the mass spectroscopy and the wave function related observables, we examine the decay constants and distribution amplitudes (DAs) up to the twist-4. The analysis of the heavy pseudoscalar mesons is carried out both in the $1S$ and $2S$ states. This investigation involves calculating the local and nonlocal matrix elements $⟨0|\overline{q}\mathrm{\Gamma }q|P⟩$ using three distinct current operators $\mathrm{\Gamma }=({\gamma }^{\mu }{\gamma }_5,i{\gamma }_5,{\sigma }^{\mu \nu }{\gamma }_5)$. Considering a general reference frame where ${\mathbf{P}}_{\perp }\ne 0$ and investigating all available current components, we examine not only the frame independence but also the component independence of the decay constants. The explicit findings from our study provide the evidence for the equality of the three pseudoscalar meson decay constants obtained from the three distinct current operators $\mathrm{\Gamma }$. The notable agreement in decay constants is attained by imposing the Bakamjian-Thomas construction of the LFQM, namely, the meson state is constructed by the noninteracting quark and antiquark representations while the interaction is added to the mass operator, which provides the self-consistency condition replacing the physical mass $M$ with the invariant mass $M_0$ for the noninteracting quark-antiquark representation of the meson state. In addition to obtaining the process-independent pseudoscalar meson decay constant, regardless of the choice of current operators $\mathrm{\Gamma }$, we further demonstrate its explicit Lorentz and rotation invariance. In particular, we present the analysis conducted on the twist-4 DA derived from the minus component of the axial-vector current. Finally, we discuss the various twist DAs and their $\xi$-moments associated with the $1S$ and $2S$ heavy pseudoscalar mesons.

The decay $B^{-}\to {\mathrm{\Lambda }}_c^{+}{\overline{\mathrm{\Lambda }}}_c^{-}{K}^{-}$ is studied in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13\mathrm{TeV}$ using data corresponding to an integrated luminosity of $5{\mathrm{fb}}^{-1}$ collected by the LHCb experiment. In the ${\mathrm{\Lambda }}_c^{+}{K}^{-}$ system, the ${\mathrm{\Xi }}_c(2930{)}^0$ state observed at the BABAR and Belle experiments is resolved into two narrower states, ${\mathrm{\Xi }}_c(2923{)}^0$ and ${\mathrm{\Xi }}_c(2939{)}^0$, whose masses and widths are measured to be $m({\mathrm{\Xi }}_c(2923{)}^0)=2924.5\pm 0.4\pm 1.1\mathrm{MeV}$, $m({\mathrm{\Xi }}_c(2939{)}^0)=2938.5\pm 0.9\pm 2.3\mathrm{MeV}$, $\mathrm{\Gamma }({\mathrm{\Xi }}_c(2923{)}^0)=4.8\pm 0.9\pm 1.5\mathrm{MeV}$, $\mathrm{\Gamma }({\mathrm{\Xi }}_c(2939{)}^0)=11.0\pm 1.9\pm 7.5\mathrm{MeV}$, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt ${\mathrm{\Lambda }}_c^{+}{K}^{-}$ sample. Evidence of a new ${\mathrm{\Xi }}_c(2880{)}^0$ state is found with a local significance of $3.8\sigma$, whose mass and width are measured to be $2881.8\pm 3.1\pm 8.5\mathrm{MeV}$ and $12.4\pm 5.3\pm 5.8\mathrm{MeV}$, respectively. In addition, evidence of a new decay mode ${\mathrm{\Xi }}_c(2790{)}^0\to {\mathrm{\Lambda }}_c^{+}{K}^{-}$ is found with a significance of $3.7\sigma$. The relative branching fraction of $B^{-}\to {\mathrm{\Lambda }}_c^{+}{\overline{\mathrm{\Lambda }}}_c^{-}{K}^{-}$ with respect to the $B^{-}\to D^{+}{D}^{-}{K}^{-}$ decay is measured to be $2.36\pm 0.11\pm 0.22\pm 0.25$, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.

The branching fraction $\mathcal{B}(B^0\to D^{*-}{\tau }^{+}{\nu }_{\tau })$ is measured relative to that of the normalization mode $B^0\to D^{*-}{\pi }^{+}{\pi }^{-}{\pi }^{+}$ using hadronic ${\tau }^{+}\to {\pi }^{+}{\pi }^{-}{\pi }^{+}({\pi }^0){\overline{\nu }}_{\tau }$ decays in proton-proton collision data at a center-of-mass energy of 13 TeV collected by the LHCb experiment, corresponding to an integrated luminosity of $2{\mathrm{fb}}^{-1}$. The measured ratio is $\mathcal{B}(B^0\to D^{*-}{\tau }^{+}{\nu }_{\tau })/\mathcal{B}(B^0\to D^{*-}{\pi }^{+}{\pi }^{-}{\pi }^{+})=1.70\pm 0.10_{-0.10}^{+0.11}$, where the first uncertainty is statistical and the second is related to systematic effects. Using established branching fractions for the $B^0\to D^{*-}{\pi }^{+}{\pi }^{-}{\pi }^{+}$ and $B^0\to D^{*-}{\mu }^{+}{\nu }_{\mu }$ modes, the lepton universality test $\mathcal{R}(D^{*-})\equiv \mathcal{B}(B^0\to D^{*-}{\tau }^{+}{\nu }_{\tau })/\mathcal{B}(B^0\to D^{*-}{\mu }^{+}{\nu }_{\mu })$ is calculated, $\mathcal{R}(D^{*-})=0.247\pm 0.015\pm 0.015\pm 0.012$, where the third uncertainty is due to the uncertainties on the external branching fractions. This result is consistent with the Standard Model prediction and with previous measurements.

We demonstrate the importance of quantum jumps in the nonequilibrium evolution of bottomonium states in the quark-gluon plasma. Based on nonrelativistic effective field theory and the open quantum system framework, we evolve the density matrix of color singlet and octet pairs. We show that quantum regeneration of singlet states from octet configurations is necessary to understand experimental results for the suppression of both bottomonium ground and excited states. The values of the heavy-quarkonium transport coefficients used are consistent with recent lattice QCD determinations.

In holographic models of quantum chromodynamics, the running of the anomalous dimension of the quark bilinear operator leads to chiral symmetry breaking when $\gamma =1$ and the Breitenlohner-Freedman bound is violated. In that case, the running drives the sigma meson mass tachyonic inducing the chiral symmetry breaking. Here we include the running anomalous dimension in the computation of the spectrum of bound states associated with other operators made of light quarks, such as the nucleon and exotic sexaquark states. We show that including the one-loop gauge theory running can have substantial effects on the predictions. For example, the nucleon mass to rho mass ratio is improved and lies much closer to the observed value. A similar result is obtained for the $\mathrm{\Lambda }$ and $\mathrm{\Xi }$ baryon when strange quarks are included. A $uuddss$ sexaquark state with a low enough mass to make it stable can be achieved, but this depends on the input assumptions about the running dimension.

Interacting dark sectors may undergo changes in the number of their relativistic species during the early universe, due to a mass threshold $m$ (similar to changes in the Standard Model bath), and in doing so affect the cosmic history. When such changes occur close to recombination, i.e., for $m\sim (0.1–10)\mathrm{eV}$, the stringent bound on the effective number of neutrino species, $N_{\mathrm{eff}}$, can be relaxed and the value of the Hubble expansion rate $H_0$ inferred from cosmic microwave background (CMB) observations raised. We search for such sectors (with and without mass thresholds) in the latest cosmological datasets, including the full-shape (FS) of BOSS DR12 galaxy power spectrum. We perform a detailed analysis, accounting for the choice of prior boundaries and additionally exploring the possible effects of dark sector interactions with (a fraction of) the dark matter. We find $\mathrm{\Delta }{N}_{\mathrm{eff}}\le 0.55(0.46)$ at 95% confidence level (CL) with (without) a mass threshold. While a significantly larger Hubble rate is achieved in this scenario, $H_0=69.01_{-1.1}^{+0.66}$, the overall fit to $\mathrm{CMB}+\mathrm{FS}$ data does not provide a compelling advantage over the $\mathrm{\Lambda }\mathrm{CDM}$ model. Furthermore, we find that dark matter interactions with the dark sector do not significantly improve the (matter fluctuations) $S_8$ tension with respect to the $\mathrm{\Lambda }\mathrm{CDM}$ model. Our work provides model-independent constraints on (decoupled) dark sectors with mass thresholds around the eV scale.