We present a unified theory of inflation, neutrino mass, baryogenesis, and dark matter where global lepton number symmetry and its breaking play a crucial role. The basic idea is to use a lepton number carrying a complex scalar field as the inflaton as well as the field that implements Affleck-Dine (AD) leptogenesis. Dark matter is the massive Majoron which is a pseudo-Goldstone boson, resulting from the spontaneous breaking of lepton number symmetry supplemented by explicit lepton number violation needed to implement AD leptogenesis. The magnitude of the resulting $n_B/s$ in the model is related to the mass of the pseudo-Goldstone dark matter, connecting two apparently disconnected cosmological observations. An inverse seesaw mechanism with lepton number breaking at low scale is crucial to prevent washout of the lepton asymmetry during the universe’s evolution. The model seems to provide an economical solution to several puzzles of the standard model of particle physics and cosmology in one stroke.

We explore the direct Higgs boson-top $CP$ measurement via the $pp\to t\overline{t}h$ channel at the high-luminosity LHC. We show that a combination of machine learning techniques and efficient kinematic reconstruction methods can boost new physics sensitivity, effectively probing the complex $t\overline{t}h$ multiparticle phase space. Special attention is devoted to top quark polarization observables, uplifting the analysis from a raw rate to a polarization study. Through a combination of hadronic, semileptonic, and dileptonic top pair final states in association with $h\to \gamma \gamma$, we obtain that the HL-LHC can probe the Higgs boson-top coupling modifier and $CP$ phase, respectively, up to $|{\kappa }_t|\lesssim 8\%$ and $|\alpha |\lesssim 13°$ at 68% C.L.

Experiments that use liquid noble gases as target materials, such as argon and xenon, play a significant role in direct detection searches for weakly interacting massive particles(-like) dark matter. As these experiments grow in size, they will soon encounter a new background to their dark matter discovery potential from neutrino scattering off nuclei and electrons in their targets. Therefore, a better understanding of this new source of background is crucial for future large-scale experiments such as ARGO and DARWIN. In this work, we study the impact of atmospheric neutrino flux uncertainties, electron recoil rejection efficiency, recoil energy sensitivity, and other related factors on the dark matter discovery reach. We also show that a significant improvement in sensitivity can potentially be obtained, at large exposures, by combining data from independent argon and xenon experiments.

In this work, we study the status of negative coupling modifiers in extended Higgs sectors, focusing on the ratio of coupling modifiers that probes custodial symmetry violation ${\lambda }_{WZ}={\kappa }_W/{\kappa }_Z$. Higgs sectors with multiplets larger than doublets are the only weakly coupled models that give tree-level modifications to ${\lambda }_{WZ}$, and we explore all such models allowed by the constraint from the $\rho$ parameter and perturbative unitarity. This class of models has a custodial symmetry violating potential, while the vacuum configuration preserves the symmetry. We apply precision measurements from ATLAS and CMS and show that each dataset can exclude a vast set of models with ${\lambda }_{WZ}<0$ at greater than 95% confidence level. We give evidence that ${\lambda }_{WZ}<0$ is excluded in all weakly coupled models.

We analyze the pseudocritical behavior of three-flavor QCD using highly improved staggered quarks on lattices with temporal extent $N_{\tau }=8$ and for quark masses corresponding to a pseudoscalar Goldstone mass in the range $80\mathrm{MeV}\lesssim m_{\pi }\lesssim 140\mathrm{MeV}$. Our findings are consistent with the occurrence of a second order chiral phase transition at vanishing values of the quark masses. The chiral phase transition temperature at this finite value of the lattice spacing is determined to be $T_c={98}_{-6}^{+3}\mathrm{MeV}$. A comparison with a corresponding analysis performed in ($2+1$)-flavor QCD suggests that the continuum limit extrapolated chiral phase transition temperature in three-flavor QCD will turn out to be below 90 MeV.

We study the dynamical generation of scalar mesons in the light quark sector ($q\in \{u,d,s\}$) and calculate the masses and widths for the $f_0(500)$, $a_0(980)$, and $f_0(980)$. To this end we study the mixing of conventional $q\overline{q}$ and “exotic” $q\overline{q}q\overline{q}$ states via a coupled set of two-body Bethe-Salpeter equations based on a symmetry-preserving truncation of the underlying Dyson-Schwinger equations. This allows us to determine the dominant components of each state. Furthermore, we extend our previous framework into the complex energy plane such that we can study the analytic structure of the states in question and extract their width. At the physical point of small quark masses, the $\sigma$ meson is predominantly a $\pi \pi$ resonance. Consequently, its mass and width is driven by the effects of chiral symmetry breaking. At larger quark masses, however, the conventional $q\overline{q}$ components take over. Furthermore, we find a strong molecular $K\overline{K}$ component for both, the strange-light $f_0(980)$ and the $a_0(980)$.

In this paper we study the gluon and valence quark distributions in the pion and kaon in nuclear medium for various nuclear densities as well as in vacuum within the Nambu–Jona-Lasinio (NJL) model with the help of the proper-time regularization scheme which simulates a confinement of QCD. The nuclear medium effect is also determined in the same model for the symmetric nuclear matter. We then analyze the gluon and valence quark distributions for the bound pion and kaon in symmetric nuclear matter as well as those in vacuum. We find that the valence quark and gluon distributions in vacuum have relatively good agreements with the experimental data, the lattice QCD simulations, and the JAM Monte-Carlo (MC) global fit QCD analysis. Evolving to the higher factorization scale $Q=4\mathrm{GeV}$, the in-medium gluon and valence-quark distributions of the pion for various nuclear densities are turned out to be almost unchanged in comparison to the vacuum cases. On the contrary, for the kaon, they increase significantly with respect to the densities. Finally, we find that the vacuum gluon distribution for the kaon is smaller than that for the pion, which is consistent with other theoretical predictions. This feature holds for the in-medium gluon distribution in the nuclear density up to the saturation density.

The LHCb experiment at CERN has discovered a doubly charmed isoscalar tetraquark $T_{cc}$ with the quantum numbers of $cc\overline{u}\overline{d}$ and mass of about $3875\mathrm{MeV}/c^2$, decaying to $D^0{D}^0{\pi }^{+}$ through the intermediate channel $D^{*+}{D}^0$. We present a study of its strange companions with the quantum numbers of $cc\overline{q}\overline{s}$, where $q=u$, $d$ and isospin violation is neglected.

In this work we report the calculation of the total cross section for pion-production by the dispersion of neutrinos on nucleons. We use a consistent formalism for the intermediate resonance states of spin-$\frac{3}{2}$, taking care on the conditions imposed by the invariance on contact transformations and using the Sachs parametrization for the form factors. In addition, we incorporate states in the second resonance region up to 1.6 GeV and implement different approaches for all the dressed resonance propagators. In addition to the $\mathrm{\Delta }(1232)$, we include the $N^{*}(1440)$, $N^{*}(1535)$, and $N^{*}(1520)$ resonance contributions, and it is shown that this inclusion improves the description of the total cross section regarding a model where only the $\mathrm{\Delta }(1230)$ resonance is considered. Also, results for antineutrinos are properly described.

We study the quasi-two-body $D\to SP$ decays and the three-body $D$ decays proceeding through intermediate scalar resonances, where $S$ and $P$ denote scalar and pseudoscalar mesons, respectively. Our main results are the following: (i) Certain external and internal $W$-emission diagrams with the emitted meson being a scalar meson are naïvely expected to vanish, but they actually receive contributions from vertex and hard spectator-scattering corrections beyond the factorization approximation. (ii) For light scalars with masses below or close to 1 GeV, it is more sensible to study three-body decays directly and compare with experiment as the two-body branching fractions are either unavailable or subject to large finite-width effects of the scalar meson. (iii) We consider the two-quark (scheme I) and four-quark (scheme II) descriptions of the light scalar mesons, and find the latter generally in better agreement with experiment. This is in line with recent BESIII measurements of semileptonic charm decays that prefer the tetraquark description of light scalars produced in charmed meson decays. (iv) The topological amplitude approach fails here as the $D\to SP$ decay branching fractions cannot be reliably inferred from the measurements of three-body decays, mainly because the decay rates cannot be factorized into the topological amplitude squared and the phase space factor. (v) The predicted rates for $D^0\to f_{0}P,a_{0}P$ are generally smaller than experimental data by one order of magnitude, presumably implying the significance of $W$-exchange amplitudes. (vi) The $W$-annihilation amplitude is found to be very sizable in the $SP$ sector with $|A/T{|}_{SP}\sim 1/2$, contrary to its suppression in the $PP$ sector with $|A/T{|}_{PP}\sim 0.18$. (vii) Finite-width effects are very important for the very broad $\sigma /f_0(500)$ and $\kappa /K_0^{*}(700)$ mesons. The experimental branching fractions $\mathcal{B}(D^{+}\to \sigma {\pi }^{+})$ and $\mathcal{B}(D^{+}\to {\overline{\kappa }}^0{\pi }^{+})$ are thus corrected to be $(3.8\pm 0.3)\times {10}^{-3}$ and $(6.7_{-4.5}^{+5.6})\%$, respectively.

We study the process of black brane evaporation through the emission of D-branes. Black branes in asymptotically anti–de Sitter spacetimes, holographically dual to field theory states at finite temperature and density, have previously been found to exhibit an instability due to brane nucleation. Working in the setting of D3-branes on the conifold, we construct static Euclidean solutions describing this nucleation to leading order—D3-branes bubbling off the horizon. Furthermore, we analyze the late-time dynamics of such a D3-brane bubble as it expands and find a steady-state solution including the wall profile and its speed.

Generation of magnetic field during inflation can explain its presence over a wide range of scales in the Universe. In [Sharma et al Phys. Rev. D 96, 083511 (2017)], we proposed a model to generate these fields during inflation. These fields have nonzero anisotropic stress which lead to the generation of a stochastic background of gravitational waves (GW) in the early universe. Here we show that for a scenario of magnetogenesis where reheating takes place around QCD epoch, this stochastic GW background lies in the 95% confidence region of the stochastic common spectrum process probed by NANOGrav collaboration. This is the case when the generated electromagnetic field (EM) energy density is 3%–10% of the background energy density at the end of reheating. For this case, the values of magnetic field strength $B_0\sim (0.7–1.4)\times {10}^{-11}\mathrm{G}$ and its coherence length $\sim 3\mathrm{kpc}$ at the present epoch. These values are for the models in which EM fields are of nonhelical nature. For the helical nature of the fields, these values are $B_0\sim (2.1–3.8)\times {10}^{-10}\mathrm{G}$ and its coherence length $\sim 90\mathrm{kpc}$.

The doubly charmed exotic state $T_{cc}$ recently discovered by the LHCb Collaboration could well be a $D{D}^{*}$ molecular state long predicted in various theoretical models, in particular, the $D{D}^{*}$ isoscalar axial vector molecular state predicted in the one-boson-exchange model. In this work, we study the $DD{D}^{*}$ system in the Gaussian expansion method with the $D{D}^{*}$ interaction derived from the one-boson-exchange model and constrained by the precise binding energy of $273\pm 63\mathrm{keV}$ of $T_{cc}$ with respect to the $D^{*+}{D}^0$ threshold. We show the existence of a $DD{D}^{*}$ state with a binding energy of a few hundred keV, isospin $1/2$, and spin-parity $1^{-}$. Its main decay modes are $DDD\pi$ and $DDD\gamma$. The existence of such a state could in principle be confirmed with the upcoming LHC data and will unambiguously determine the nature of the $T_{cc}^{+}$ state and of the many exotic states of similar kind, thus deepening our understanding of the nonperturbative strong interaction.

We compute the Rényi entropies of the massless Dirac field on the Euclidean torus (the Lorentzian cylinder at nonzero temperature) for arbitrary spatial regions. We do it by the resolvent method, i.e., we express the entropies in terms of the resolvent of a certain operator and then use the explicit form of that resolvent, which was obtained recently. Our results are different in appearance from those already existing in the literature (obtained via the replica trick), but they agree perfectly, as we show numerically for noninteger order and analytically for integer order. We also compute the Rényi mutual information, and find that, for appropriate choices of the parameters, it is nonpositive and nonmonotonic. This behavior is expected, but it cannot be seen with the simplest known Rényi entropies in quantum field theory because they are proportional to the entanglement entropy.

We study the influence of the environment-induced interatomic interaction, which is usually neglected, on the entanglement dynamics of two uniformly accelerated atoms coupled with fluctuating massless scalar fields in the Minkowski vacuum. When the two-atom system is initially prepared in a separable state such that the two atoms are in the ground and excited states respectively, the environment-induced interatomic interaction assists entanglement generation, in the sense that the parameter space of acceleration and interatomic separation that allows entanglement generation is enlarged, the rate of entanglement generation at the initial time is enhanced, and the maximum of concurrence generated during evolution is increased compared with when the environment-induced interaction is neglected. Remarkably, the rate of entanglement generation at the initial time and the maximal concurrence generated during evolution decrease monotonically with the acceleration, in contrast to that they exhibit a nonmonotonic behavior as the acceleration varies when the environment-induced interatomic interaction is neglected. In other words, the anti-Unruh phenomenon in terms of the entanglement generation is deprived of by the consideration of the environment-induced interatomic interaction.

We study the axial quasinormal modes of hairy black holes in Gauss-Bonnet gravity with a massive self-interacting scalar field. Two coupling functions of the scalar field to the Gauss-Bonnet invariant are adopted with one of them leading to black hole scalarization. The axial perturbations are studied via time evolution of the perturbation equation, and the effect of the scalar field mass and the self-interaction constant on the oscillation frequency and damping time is examined. We study as well the effect of nonzero scalar field potential on the critical point at which the perturbation equation loses hyperbolicity in the case of black hole scalarization. The results show that the nonzero scalar field potential extends the range of parameters where such a loss of hyperbolicity is observed thus shrinking the region of stable black hole existence. This will have an important effect on the nonlinear dynamical simulation studies in massive scalar Gauss-Bonnet gravity.

Simpson-Visser (SV) spacetimes are the simplest globally regular modifications of the Schwarzschild, Reissner-Nordsröm and other black hole solutions of general relativity. They smoothly interpolate between these black holes and traversable wormholes. After a brief presentation of the Schwarzschild-like and Reissner-Nordsröm-like SV geometries, including their Carter-Penrose diagrams, we show that any static, spherically symmetric SV metric can be obtained as an exact solution to the Einstein field equations sourced by a combination of a minimally coupled phantom scalar field with a nonzero potential $V(\varphi )$ and a magnetic field in the framework of nonlinear electrodynamics with the Lagrangian $\mathcal{L}(F)$, $\mathcal{F}=F_{\mu \nu }{F}^{\mu \nu }$ (in standard notations). Explicit forms of $V(\varphi )$ and $\mathcal{L}(F)$ are presented for the cases of Schwarzschild-like and Reissner-Nordsröm-like SV metrics.

We study the mass-radius relation and the second Love number of compact objects made of ordinary matter and non-self-annihilating fermionic dark matter for a wide range of dark matter particle masses, and for the cases of weakly and strongly interacting dark matter. We obtain stable configurations of compact objects with radii smaller than 10 km and masses similar to Earth- or Jupiter-like stellar objects. In certain parameter ranges, we find second Love numbers which are markedly different compared to those expected for neutron stars without dark matter. Thus, by obtaining the compactness of these compact objects and measuring their tidal deformability from gravitational wave detections from binary neutron star mergers, the extracted value of the second Love number would allow us to determine the existence of dark matter inside neutron stars irrespective of the equation of state of ordinary matter.

The ringdown data of both GW150914 and GW190521_074359 (GW190521r) show evidence supporting the presence of an overtone. All of the previous studies adopt a fundamental assumption, which was motivated more by convenience than by first principles, that the first overtone and the fundamental mode share a same onset. In this work, for the first time, we relax such an assumption, and we aim to probe the possible chromatic onsets of these two components within the GW150914 and GW190521r ringdown data. For both events, we bound the onset lags to be $\mathrm{\Delta }{t}_0\ge 5M_f$ at probabilities of $\ge 94.7\%$, where $M_f$ is the mass of the remnant black hole formed in the merger. This result moderately favors the nonsimultaneous excitation between the fundamental mode and the first overtone in the ringdown.