A simple theory where the total lepton number is a local gauge symmetry is proposed. In this context, the gauge anomalies are canceled with the minimal number of extra fermionic fields and one predicts that the neutrinos are Majorana fermions. The properties of the neutrino sector are discussed, showing that this theory predicts a $3+2$ light neutrino sector. We show that using the same fermionic fields one can gauge the baryon number and define a simple theory where the lepton and baryon numbers can be spontaneously broken at the low scale in agreement with experiments.

We discuss the potential of using long-lived particle (LLP) searches for right-handed neutrinos (RHNs) to test resonant leptogenesis and the seesaw mechanism. This is challenging if only RHNs are added to the Standard Model, as naturally the active-sterile mixing strengths $|V_{\ell N}{|}^2$ are small, for $1\mathrm{GeV}\lesssim M_N\lesssim 1000\mathrm{GeV}$. Instead, we consider the minimal $B-L$ gauge model, where a $Z^{\prime }$ gauge boson couples to fermions including the RHNs. During leptogenesis, this gauge coupling introduces scattering processes that washout the $B-L$ asymmetry. At colliders, it can lead to abundant production of RHNs which allows probing the associated seesaw mechanism using LLP searches. We find that LLP searches at the FCC-hh can test leptogenesis and the seesaw mechanism simultaneously and probe the active-sterile mixing at or below the seesaw floor.

In this paper, we perform a comprehensive study of lepton flavor violation (LFV) in semileptonic transitions in the framework of an effective field theory with general flavor structure. We account for the renormalization group equations, which induce nontrivial correlations between the different types of LFV processes. In particular, we show that these loop effects are needed to improve the bounds on several coefficients that are not efficiently constrained at tree level. For illustration, we consider a few concrete scenarios, with predominant couplings to third-generation quarks, and we explore the correlations between the various tree- and loop-level constraints on these models. As a by-product, we also provide expressions for several semileptonic LFV meson decays by using the latest determinations of the relevant hadronic form factors on the lattice.

Thermal relic dark matter below $\sim 10\mathrm{GeV}$ is excluded by cosmic microwave background data if its annihilation to visible particles is unsuppressed near the epoch of recombination. Usual model-building measures to avoid this bound involve kinematically suppressing the annihilation rate in the low-velocity limit, thereby yielding dim prospects for indirect detection signatures at late times. In this work, we investigate a class of cosmologically viable sub-GeV thermal relics with late-time annihilation rates that are detectable with existing and proposed telescopes across a wide range of parameter space. We study a representative model of inelastic dark matter featuring a stable state ${\chi }_1$ and a slightly heavier excited state ${\chi }_2$ whose abundance is thermally depleted before recombination. Since the kinetic energy of dark matter in the Milky Way is much larger than it is during recombination, ${\chi }_1{\chi }_1\to {\chi }_2{\chi }_2$ upscattering can efficiently regenerate a cosmologically long-lived Galactic population of ${\chi }_2$, whose subsequent coannihilations with ${\chi }_1$ give rise to observable gamma-rays in the $\sim 1\mathrm{MeV}-100\mathrm{MeV}$ energy range. We find that proposed MeV gamma-ray telescopes, such as e-ASTROGAM, AMEGO, and MAST, would be sensitive to much of the thermal relic parameter space in this class of models and thereby enable both discovery and model discrimination in the event of a signal at accelerator or direct detection experiments.

We study the possibility of generating dark matter (DM) purely from ultralight primordial black hole (PBH) evaporation with the latter being produced from a first order phase transition (FOPT) in the early Universe. If such ultralight PBH leads to an early matter domination, it can give rise to a doubly peaked gravitational wave (GW) spectrum in Hz-kHz ballpark with the low frequency peak generated from PBH density fluctuations being within near future experimental sensitivity. In the subdominant PBH regime, the FOPT generated GW spectrum comes within sensitivity due to absence of entropy dilution. In both the regimes, PBH mass from a few kg can be probed by GW experiments like BBO, ET, CE, UDECIGO etc. while DM mass gets restricted to the superheavy ballpark in the PBH dominance case. Apart from distinct DM mass ranges in the two scenarios, GW observations can differentiate by measuring their distinct spectral shapes.

Dilaton effective field theory (dEFT) describes the long distance behavior of certain confining, near-conformal gauge theories that have been studied via lattice computation. Pseudo-Nambu- Goldstone bosons (pNGBs), emerging from the breaking of approximate, continuous, internal symmetries, are coupled to an additional scalar particle, the dilaton, arising from the spontaneous breaking of approximate scale invariance. This effective theory has been employed to study possible extensions of the standard model. In this paper, we propose a complementary role for dEFT, as a description of the dark matter of the Universe, with the pNGBs identified as the dark matter particles. We show that this theory provides a natural implementation of the “forbidden” dark matter mechanism, and we identify regions of parameter space for which the thermal history of dEFT yields the measured dark matter relic density.

The normalization of the leading-twist photon distribution amplitude (DA), $f_{\gamma }^{\perp }$, is an important ingredient in the study of exclusive processes involving the photon emission by means of QCD sum-rules. In this paper we determine the up-, down- and strange-quark contribution to $f_{\gamma }^{\perp }$ by exploiting its relation to the zero-momentum two-point correlation function of the electromagnetic current $J_{\mathrm{em}}^{\mu }$ and the electric component of the tensor current $T^{\mu \nu }$. To that end we employ the gauge ensembles obtained by using $N_f=2+1+1$ Wilson-Clover twisted-mass quark flavors, generated by the Extended Twisted Mass (ETM) Collaboration, and after adding all sources of systematic uncertainties, we obtain a total error of 1.5% and 3.5%, respectively, for the light- ($u$ and $d$) and strange-quark contribution to $f_{\gamma }^{\perp }(2\mathrm{GeV})$ in the $\overline{\mathrm{MS}}$ scheme, thus improving their accuracy by a factor of 2.3 and 2.8, respectively. For the strange-quark contribution $f_{\gamma ,s}^{\perp }(2\mathrm{GeV})$, we observe a discrepancy with respect to previous lattice calculations. By combining our result with the world average lattice value of the chiral condensate, we obtain for the susceptibility of the quark condensate ${\chi }_d^{\overline{\mathrm{MS}}}(2\mathrm{GeV})\simeq {\chi }_u^{\overline{\mathrm{MS}}}(2\mathrm{GeV})=2.17(12){\mathrm{GeV}}^{-2}$.

While neutrino oscillations have led to attention and research on field mixing arising from quadratic interactions, the field mixing inherent in clothed particles is more fundamental, serving as a significant source of complexity and nonperturbative challenges in quantum field theory. We present an example of an analytical solution for field mixing involving a three-point interaction between a bosonic field and a fermionic field. Specifically, we study the Rothe-Stamatescu (RS) model and utilize lattice regularization to provide a well-defined Hamiltonian that is absent in the original continuous RS model. Because of the complexity introduced by three-point interactions compared to quadratic interactions, the Fock representation commonly used in discussions of field mixing does not work well; instead, we define a representation based on real space to investigate the physical vacuum and clothed particles. These eigenstates not only reveal the field mixing between the bosonic and fermionic fields but also allow us to directly observe the spatial entanglement structure.

Recently, several pentaquark states $P_{css}$, with global flavor $\overline{c}cssn$, have been predicted within a theoretical framework based on unitary coupled channels. We study theoretically the feasibility to observe the $P_{css}$ with $I(J^P)=\frac{1}{2}({\frac{1}{2}}^{-})$ in the decays ${\mathrm{\Xi }}_b^0\to \eta {\eta }_c{\mathrm{\Xi }}^0$ and ${\mathrm{\Omega }}_b^{-}\to K^{-}{\eta }_c{\mathrm{\Xi }}^0$. Indeed, within the model, the ${\eta }_c{\mathrm{\Xi }}^0$ channel is the lowest mass pseudoscalar-baryon channel to which this pentaquark state couples, thus we can expect to observe its signal in the ${\eta }_c{\mathrm{\Xi }}^0$ invariant mass distribution of the mentioned decays. We identify the dominant weak decay processes and then implement the hadronization into the different meson-baryon channels in the final state, linked by flavor symmetry. The dominant meson-baryon final state interaction is then implemented to generate the full amplitude, implicitly accounting for the dynamical emergence of the pentaquark states. We obtain a clear Breit-Wigner-like resonant signal in the spectrum of the ${\mathrm{\Omega }}_b^{-}$ decay, exceeding that in the ${\mathrm{\Xi }}_b^0$ decay by two to three orders of magnitude. In the case of the latter decay, the resonant state would manifest as a significant dip in the spectrum. We study the feasibility of searching for these $b$-hadron decay modes and analyzing their resonant components using the current and future data samples from the LHCb experiment.

Prompted by a recent lattice QCD calculation, we review the SU(3) light quark flavor structure of charmed tetraquarks with spin 0 diquarks. Fermi statistics forces the three light quarks to be in the representation $\overline{\mathbf{3}}\otimes \overline{\mathbf{3}}=\mathbf{3}\oplus \overline{\mathbf{6}}$. This agrees with the weak repulsion in the $\mathbf{15}$ of the $\mathbf{3}\otimes \mathbf{8}$ in $\overline{D}K$ scattering studied on the lattice. We analyze the $\mathbf{3}\oplus \overline{\mathbf{6}}$ multiplet broken by the strange quark mass and determine the five independent masses from the known masses of diquarks. The mass of $D_{s0}^{*}(2317)$ is predicted within 50 MeV accuracy. The recently observed ${\overline{D}}_s^{--}(2900)$ and ${\overline{D}}_s^0(2900)$, likely part of a $I=1$ multiplet, with flavor composition $\overline{c}\overline{q}{q}^{\prime }s$, and $X_0(2900)$, an isosinglet with flavor composition $\overline{c}\overline{s}ud$, fit naturally in a $\mathbf{3}\oplus \overline{\mathbf{6}}$ structure as the first radial excitations. We discuss also the decay modes of $D_{s0}^{*}(2317)$, of the radial excitations and of the predicted particles.

We compute electromagnetic and two-photon transition form factors of ground-state pseudoscalar mesons: $\pi ,K,{\eta }_c,{\eta }_b$. To this end, we employ an algebraic model based upon the coupled formalism of Schwinger-Dyson and Bethe-Salpeter equations. Within this approach, the dressed quark propagator and the relevant Bethe-Salpeter amplitude encode the internal structure of the corresponding meson. Electromagnetic properties of the meson are probed via the quark-photon interaction. The algebraic model employed by us unifies the treatment of all ground-state pseudoscalar mesons. Its parameters are carefully fitted performing a global analysis of existing experimental data including the knowledge of the charge radii of the mesons studied. We then compute and predict electromagnetic and two-photon transition form factors for a wide range of probing photon momentum-squared which is of direct relevance to the experimental observations carried out thus far or planned at different hadron physics facilities such as the Thomas Jefferson National Accelerator Facility (JLab) and the forthcoming Electron-Ion Collider. We also present comparisons with other theoretical models and approaches and lattice quantum chromodynamics.

The inclusive production of the charm-strange baryon ${\mathrm{\Omega }}_{\mathrm{c}}^0$ is measured for the first time via its semileptonic decay into ${\mathrm{\Omega }}^{-}{\mathrm{e}}^{+}{\nu }_{\mathrm{e}}$ at midrapidity ($|y|<0.8$) in proton-proton (pp) collisions at the center-of-mass energy $\sqrt{s}=13\mathrm{TeV}$ with the ALICE detector at the LHC. The transverse momentum ($p_{\mathrm{T}}$) differential cross section multiplied by the branching ratio is presented in the interval $2<p_{\mathrm{T}}<12\mathrm{GeV}/c$. The branching-fraction ratio $\mathrm{BR}({\mathrm{\Omega }}_{\mathrm{c}}^0\to {\mathrm{\Omega }}^{-}{\mathrm{e}}^{+}{\nu }_{\mathrm{e}})/\mathrm{BR}({\mathrm{\Omega }}_{\mathrm{c}}^0\to {\mathrm{\Omega }}^{-}{\pi }^{+})$ is measured to be $1.12\pm 0.22$ (stat) $\pm 0.27$ (syst). Comparisons with other experimental measurements, as well as with theoretical calculations, are presented.

As shown in the classic work of Belinski, Khalatnikov and Lifshitz, the approach to a generic spacelike singularity in general relativity consists of a sequence of epochs and eras in which the metric is locally Kasner, connected by brief transitions. When quantum gravity effects are included, we argue that a new type of transition arises, giving rise to Kasner eons: periods which are dominated by emergent physics at each energy scale. We comment on the different ways in which the Einsteinian eon may come to an end and show explicitly how additional Kasner eons arise in the interior of a black hole solution due to higher-derivative corrections.

In this study, we investigate the behavior of entanglement properties in the QCD phase diagram using holographic Einstein-Maxwell-dilaton models. We consider two representative holographic QCD models and examine various entanglement measures, including entanglement entropy, conditional mutual information, and the entanglement of purification. We find that the entanglement entropy obtained using the direct UV-cutoff renormalization method shows significant dependence on the specific model being used. However, the outcomes of other nondivergent entanglement measures, such as cutoff-independent entanglement entropy, conditional mutual information, and the entanglement of purification, exhibit congruence in our calculations. When we focus specifically on the temperature range below 300 MeV, we observe a similar behavior among the three entanglement measures. This may suggest that within this temperature range, the entanglement of QCD matter decreases with increasing temperature. Additionally, we observe distinct phase transition behaviors of entanglement properties at the critical end point and first-order phase transitions. This observation highlights the potential of entanglement properties as effective order parameters for QCD matter phase transitions.

This paper proposes an alternative regularization method for handling the ultraviolet behavior of entanglement entropy. Utilizing an $i\epsilon$ prescription in the Euclidean double cone geometry, it accurately reproduces the universal behavior of entanglement entropy. The method is demonstrated in the free boson theory in arbitrary dimensions and two-dimensional conformal field theories. The findings highlight the effectiveness of the $i\epsilon$ regularization method in addressing ultraviolet issues in quantum field theory and gravity, suggesting potential applications to other calculable quantities.

Applying the holographic method, we investigate correlation functions of boundary and defect conformal field theories. To describe boundary conformal field theory, we consider an end of the world brane in an asymptotic AdS space, which behaves as a boundary in the dual conformal field theory. In this holographic setup, we calculate correlation functions involving the reflection effect at the boundary. We show that, when the end of the world brane has no degrees of freedom, the holographic calculation reproduces the correlation functions known in the boundary conformal field theory. When the boundary has nontrivial boundary entropy, we calculate one- and two-point functions nontrivially relying on the boundary entropy. We further study correlation functions of defect conformal field theory after introducing a $p$ brane. We directly derive a bulk-to-defect two-point function without introducing an image operator and determine the coefficient of the two-point function exactly in the holographic setup.

The renormalization group method, more specifically the Wegner-Houghton equation, is used to find first order phase transitions in a simple scalar field theory with a polynomial potential. An improved definition of the running parameters allows us to explore the renormalization group flow down to the IR endpoint and to locate phase transitions. Beyond the expected first order transition further radiative correction generated first and second order transitions are found. The phase diagram is reviewed by a Monte-Carlo simulation of the lattice regulated version of the theory but the serious slow down of the convergence prevents us from obtaining conclusive results from the simulation.

This paper combines the post-Minkowskian expansion of general relativity with the language of intersection theory. Because of the nature of the soft limit inherent to the post-Minkowskian expansion, the intersection-based approach is of enhanced utility in that theory compared to a generic quantum field theory. In the language of intersection theory, Feynman integrals are rephrased in terms of twisted cocycles. The intersection number is a pairing between two such cocycles, and its existence allows for the direct projection onto a basis of master integrals. In this paper we use this approach to compute the second post-Minkowskian contribution to the scattering of two compact astronomical objects, getting results in agreement with previous findings.

The present work investigates the thermodynamic properties of the four-dimensional Kerr-Newmann-AdS black hole, utilizing the recently proposed framework of restricted phase space thermodynamics. This approach introduces a novel set of paired thermodynamic variables; the central charge ($C$) of the corresponding dual conformal field theory and the chemical potential ($\mu$). Through rigorous analysis, we establish fundamental relationships, including the Euler relation, Gibbs-Duhem relation, and the zeroth-order homogeneity of intensive variables. Furthermore, numerical techniques are employed to explore thermodynamic processes between the conjugate variables in canonical and grand canonical ensembles. Our investigation reveals first-order and second-order phase transitions across various macroscopic processes. Despite the absence of complete analytical expressions, our findings unveil striking similarities in behavior between Reissner-Nordström-Anti-de Sitter and Kerr-anti–de Sitter, underscoring the presence of underlying universality within the restricted phase space thermodynamics formalism.

The three observational runs of advanced LIGO and Virgo detectors have detected $\sim 90$ compact binary coalescence events with most of them being quasicircular compact binary merger events. Astrophysical models predict compact binary mergers with appreciable nonzero eccentricity if in dense stellar environments like globular clusters, active galactic nuclei discs. Gravitational wave searches from eccentric systems are either limited to very low eccentricities or rely on model-agnostic time-frequency-based searches. Typically, gravitational waves from eccentric systems with moderate eccentricities carry non-negligible energy in the eccentric higher-order modes. In this work, using the effective chirp mass model [N. Bose and A. Pai, Phys. Rev. D 104, 124021 (2021)] developed using EccentricTD waveform, we develop a phenomenological scaling relation for the eccentric higher-order mode time-frequency track. Further, we incorporate this additional information from the higher-order eccentric mode for nonspinning, stellar mass eccentric binaries to improve the constraint on eccentricity.