We unveil the dynamics of four-dimensional chiral gauge-Yukawa theories featuring several scalar degrees of freedom transforming according to distinct representations of the underlying gauge group. We consider generalized Georgi-Glashow and Bars-Yankielowicz theories. We determine, to the maximum known order in perturbation theory, the phase diagram of these theories and further disentangle their ultraviolet asymptotic nature according to whether they are asymptotically free or safe. We therefore extend the number of theories that are known to be fundamental in the Wilsonian sense to the case of chiral gauge theories with scalars.

Millimagnetically charged particles generically appear in scenarios with kinetic mixing. We present model independent bounds on these particles coming from magnetars. Schwinger pair production discharges the magnetic field of the magnetar. Thus the existence of large magnetic fields at magnetars place strong bounds on the millimagnetic charge to be smaller than ${10}^{-18}$ over a large mass range.

The two messenger results of the GeV gamma-ray excess at the Galactic center and a probable antiproton excess in the recent AMS-02 observation suggest that these two anomalies may be owing to the same origin—the dark matter (DM) annihilation into $b\overline{b}$, while these results seem in tension with the dwarf spheroidal galaxy observations. To give a compatible explanation about it, we consider the pseudoscalar DM particles $S_d^{+}{S}_d^{-}$ annihilating via $S_d^{+}{S}_d^{-}\to S_d^0{S}_d^0$, with the process mediated by a new scalar $\varphi$ and $S_d^0$ quickly decaying into $b\overline{b}$. For the particles $S_d^{+}$, $S_d^{-}$, and $S_d^0$ in a triplet with degenerate masses, the annihilation cross section of DM today is linearly dependent on the relative velocity $v_r$, and thus constraints from the dwarf spheroidal galaxies are relaxed. The parameter spaces are derived with corresponding constraints. Though traces from the new sector seem challenging to be disclosed at the collider and in DM direct detections, the indirect search of the gamma-ray line from the $S_d^0$’s decay has the potential to shed light on DM annihilations, with the energy of the gamma-ray line $\sim m_{S_d^0}/2$, i.e. about 50–75 GeV.

We use lattice regularization to study the flow of the flavor-triplet fermion current central charge $C_J^f$ from its free field value in the ultraviolet limit to its conformal value in the infrared limit of the parity-invariant three-dimensional QED with two flavors of two-component fermions. The dependence of $C_J^f$ on the scale is weak with a tendency to be below the free field value at intermediate distances. Our numerical data suggest that the flavor-triplet fermion current and the topological current correlators become degenerate within numerical errors in the infrared limit, thereby supporting an enhanced O(4) symmetry predicted by strong self-duality. Further, we demonstrate that fermion dynamics is necessary for the scale-invariant behavior of parity-invariant three-dimensional QED by showing that the pure gauge theory with noncompact gauge action has a nonzero bilinear condensate.

We derive Lüscher phase-shift formulas for two-particle states in boxes elongated in one of the dimensions. Such boxes offer a cost-effective way of varying the relative momentum of the particles. Boosted states in the elongated direction, which allow wider access to energies, are also considered. The formulas for the various scenarios (moving and zero-momentum states in cubic and elongated boxes) are compared, and relations between them are clarified. The results are applicable to a wide set of meson-meson and meson-baryon elastic scattering processes, with the two-particle system having equal or unequal masses.

We present results on the nucleon axial and induced pseudoscalar form factors using an ensemble of two degenerate twisted mass clover-improved fermions with mass yielding a pion mass of $m_{\pi }=130\mathrm{MeV}$. We evaluate the isovector and the isoscalar, as well as the strange and the charm axial form factors. The disconnected contributions are evaluated using recently developed methods that include deflation of the lower eigenstates, allowing us to extract the isoscalar, strange, and charm axial form factors. We find that the disconnected quark loop contributions are nonzero and particularly large for the induced pseudoscalar form factor.

In this paper we present results for the renormalization of gauge invariant nonlocal fermion operators which contain a Wilson line, to one-loop level in lattice perturbation theory. Our calculations have been performed for Wilson/clover fermions and a wide class of Symanzik improved gluon actions. The extended nature of such “long-link” operators results in a nontrivial renormalization, including contributions which diverge linearly as well as logarithmically with the lattice spacing, along with additional finite factors. On the lattice there is also mixing among certain subsets of these nonlocal operators; we calculate the corresponding finite mixing coefficients, which are necessary in order to disentangle individual matrix elements for each operator from lattice simulation data. Finally, extending our perturbative setup, we present nonperturbative prescriptions to extract the linearly divergent contributions.

A lattice quantum chromodynamics (LQCD) calculation of the nuclear matrix element relevant to the $nn\to ppee{\overline{\nu }}_e{\overline{\nu }}_e$ transition is described in detail, expanding on the results presented in Ref. [P. E. Shanahan et al., Phys. Rev. Lett. 119, 062003 (2017)]. This matrix element, which involves two insertions of the weak axial current, is an important input for phenomenological determinations of double-$\beta$ decay rates of nuclei. From this exploratory study, performed using unphysical values of the quark masses, the long-distance deuteron-pole contribution to the matrix element is separated from shorter-distance hadronic contributions. This polarizability, which is only accessible in double-weak processes, cannot be constrained from single-$\beta$ decay of nuclei, and is found to be smaller than the long-distance contributions in this calculation, but non-negligible. In this work, technical aspects of the LQCD calculations, and of the relevant formalism in the pionless effective field theory, are described. Further calculations of the isotensor axial polarizability, in particular near and at the physical values of the light-quark masses, are required for precise determinations of both two-neutrino and neutrinoless double-$\beta$ decay rates in heavy nuclei.

In the original Collins-Soper-Sterman (CSS) presentation of the results of transverse-momentum-dependent (TMD) factorization for the Drell-Yan process, results for perturbative coefficients can be obtained from calculations for collinear factorization. Here we show how to use these results, plus known results for the quark form factor, to obtain coefficients for TMD factorization in more recent formulations, e.g., that due to Collins, and apply them to known results at order ${\alpha }_s^2$ and ${\alpha }_s^3$. We also show that the “nonperturbative” functions as obtained from fits to data are equal in the two schemes. We compile the higher-order perturbative inputs needed for the updated CSS scheme by appealing to results obtained in a variety of different formalisms. In addition, we derive the connection between both versions of the CSS formalism and several formalisms based in soft-collinear effective theory (SCET). Our work uses some important new results for factorization for the quark form factor, which we derive.

Recent results for the total and inelastic hadronic cross sections from LHC experiments are compared with predictions from a single-channel eikonal minijet model driven by parton density functions and from an empirical model. The role of soft gluon resummation in the infrared region in taming the rise of minijets and their contribution to the increase of the total cross sections at high energies are discussed. Survival probabilities at the LHC, whose theoretical estimates range from circa 10% to a few per mille, are estimated in this model and compared with results from QCD-inspired models and from multichannel eikonal models. We revisit a previous calculation and examine the origin of these discrepancies.

The nonleptonic weak decay of ${\mathrm{\Lambda }}_c^{+}\to {\overline{K}}^0\eta p$ is analyzed from the viewpoint of probing the $N^{*}(1535)$ resonance, which has a big decay branching ratio to $\eta N$. Up to an arbitrary normalization, the invariant mass distribution of $\eta p$ is calculated with both the chiral unitary approach and an effective Lagrangian model. Within the chiral unitary approach, the $N^{*}(1535)$ resonance is dynamically generated from the final-state interaction of mesons and baryons in the strangeness zero sector. For the effective Lagrangian model, we take a Breit-Wigner formula to describe the distribution of the $N^{*}(1535)$ resonance. It is found that the behavior of the $N^{*}(1535)$ resonance in the ${\mathrm{\Lambda }}_c^{+}\to {\overline{K}}^0{N}^{*}(1535)\to {\overline{K}}^0\eta p$ decay within the two approaches is different. The proposed ${\mathrm{\Lambda }}_c^{+}$ decay mechanism can provide valuable information on the properties of the $N^{*}(1535)$ and can in principle be tested by facilities such as BEPC II and SuperKEKB.

Breaking of $G$-parity or new weak (second class) currents can be responsible for ${\tau }^{-}\to {\eta }^{(\prime )}{\pi }^{-}{\nu }_{\tau }$ decays. Forthcoming measurements of $\tau$ lepton properties at the Belle II experiment will be able to measure this decay channel for the first time. Isolating new physics contributions from the measured rates will require a careful evaluation of $G$-parity breaking contributions. Here we evaluate the one-loop contribution to ${\tau }^{-}\to {\eta }^{(\prime )}{\pi }^{-}{\nu }_{\tau }$ decays induced by the emission of two virtual photons and its later conversion into an ${\eta }^{(\prime )}$ meson. As expected, this contribution is very small and may be relevant only for new physics searches contributing at the ${10}^{-4}$ level to the decay rate of ${\tau }^{-}\to {\eta }^{(\prime )}{\pi }^{-}{\nu }_{\tau }$.

The generalized uncertainty principle (GUP) is a modification of Heisenberg’s Principle predicted by several theories of quantum gravity. It consists of a modified commutator between the position and momentum. In this work, we compute potentially observable effects that GUP implies for the harmonic oscillator, coherent, and squeezed states in quantum mechanics. In particular, we rigorously analyze the GUP-perturbed harmonic oscillator Hamiltonian, defining new operators that act as ladder operators on the perturbed states. We use these operators to define the new coherent and squeezed states. We comment on potential applications.

We prove the renormalizability of a gauge-invariant, four-dimensional group field theory (GFT) model on SU(2), whose defining interactions correspond to necklace bubbles (found also in the context of new large-N expansions of tensor models), rather than melonic ones, which are not renormalizable in this case. The respective scaling of different interactions in the vicinity of the Gaussian fixed point is determined by the renormalization group itself. This is possible because the appropriate notion of canonical dimension of the GFT coupling constants takes into account the detailed combinatorial structure of the individual interaction terms. This is one more instance of the peculiarity (and greater mathematical richness) of GFTs with respect to ordinary local quantum field theories. We also explore the renormalization group flow of the model at the nonperturbative level, using functional renormalization group methods, and identify a nontrivial fixed point in various truncations. This model is expected to have a similar structure of divergences as the GFT models of 4D quantum gravity, thus paving the way to more detailed investigations on them.

We propose new dictionaries for holographic conductors that enable us to compute carrier densities and mean velocities of charge carriers in the system. The carrier density, which differs from the charge density, is the total number density of both the positive and the negative charge carriers. The mean velocity is the mean value of the velocities of all charge carriers. These quantities are not conjugate to the sources that are given by boundary values of bulk fields, and we cannot compute them by using the conventional method in holography. In the present work, we introduce a phenomenological model of charge transport, and we establish the dictionary by comparing the results of the phenomenological model and those from the holography. We show that the mean velocity agrees with the velocity of an analog black hole on the worldvolume of the probe D-brane, and it can be read from the spectrum of the fluctuations.

In this work, we introduce classical holographic codes. These can be understood as concatenated probabilistic codes and can be represented as networks uniformly covering hyperbolic space. In particular, classical holographic codes can be interpreted as maps from bulk degrees of freedom to boundary degrees of freedom. Interestingly, they are shown to exhibit features similar to those expected from the AdS/CFT correspondence. Among these are a version of the Ryu-Takayanagi formula and intriguing properties regarding bulk reconstruction and boundary representations of bulk operations. We discuss the relation of our findings with expectations from AdS/CFT and, in particular, with recent results from quantum error correction.

We calculate quantum loop corrections to the stress-energy flux caused by moving mirrors. We consider massless, self-interacting, ${\varphi }^4$, real scalar theory. In these calculations we encounter new and quite unexpected subtleties due to the absence of global hyperbolicity in the presence of mirrors. We attempt to clearly phrase as many hidden assumptions and complications as possible that appear while solving the problem in question. On top of that, we find that quantum loop corrections to the stress-energy flux grow with time and are not suppressed in comparison with the semiclassical contributions. Thus, we observe the breakdown of the perturbation theory, and we discuss its physical origin and ways to deal with such a situation. As a byproduct, we observe a similarity of the problem in question with that for the minimally coupled, massless scalar field in de Sitter space.

We present a covariant formulation for constructing general quadratic actions for cosmological perturbations, invariant under a given set of gauge symmetries for a given field content. This approach allows us to analyze scalar, vector, and tensor perturbations at the same time in a straightforward manner. We apply the procedure to diffeomorphism invariant single-tensor, scalar-tensor, and vector-tensor theories and show explicitly the full covariant form of the quadratic actions in such cases, in addition to the actions determining the evolution of vector and tensor perturbations. We also discuss the role of the symmetry of the background in identifying the set of cosmologically relevant free parameters describing these classes of theories, including calculating the relevant free parameters for an axisymmetric Bianchi-I vacuum universe.

We consider an alternative to weakly interacting massive particle (WIMP) cold dark matter (CDM)—ultralight bosonic dark matter ($m\gtrsim {10}^{-22}\mathrm{eV}/c^2$) described by a complex scalar field (SFDM) with a global $U(1)$ symmetry—for which the comoving particle number density or charge density is conserved after particle production during standard reheating. We allow for a repulsive self-interaction. In a $\mathrm{\Lambda }\mathrm{SFDM}$ universe, SFDM starts out relativistic, evolving from stiff ($w=1$) to radiation-like ($w=1/3$), before becoming nonrelativistic at late times ($w=0$). Thus, before the familiar radiation-dominated era, there is an earlier era of stiff-SFDM domination. During both the stiff-SFDM-dominated and radiation-dominated eras, the expansion rate is higher than in $\mathrm{\Lambda }\mathrm{CDM}$. The SFDM particle mass $m$ and quartic self-interaction coupling strength $\lambda$ are therefore constrained by cosmological observables, particularly $N_{\text{eff}}$, the effective number of neutrino species during big bang nucleosynthesis, and $z_{\mathrm{eq}}$, the redshift of matter-radiation equality. Furthermore, since the stochastic gravitational-wave background (SGWB) from inflation is amplified during the stiff-SFDM-dominated era, it can contribute a radiation-like component large enough to affect these observables by further boosting the expansion rate after the stiff era ends. Remarkably, this same amplification makes detection of the SGWB possible at high frequencies by current laser interferometer experiments, e.g., aLIGO/Virgo and LISA. For SFDM particle parameters that satisfy these cosmological constraints, the amplified SGWB is detectable by LIGO for a broad range of reheat temperatures $T_{\text{reheat}}$, for values of the tensor-to-scalar ratio $r$ currently allowed by cosmic microwave background polarization measurements. For a given $r$ and $\lambda /(m{c}^2{)}^2$, the marginally allowed $\mathrm{\Lambda }\mathrm{SFDM}$ model for each $T_{\text{reheat}}$ has the smallest $m$ that satisfies the cosmological constraints, and maximizes the present SGWB energy density for that $T_{\text{reheat}}$. This SGWB is then maximally detectable for values of $T_{\text{reheat}}$ for which modes that reenter the horizon when reheating ended have frequencies today that lie within the LIGO sensitive band. For example, for the family of marginally allowed models with $r=0.01$ and $\lambda /(m{c}^2{)}^2={10}^{-18}{\mathrm{eV}}^{-1}{\mathrm{cm}}^3$, the maximally detectable $\mathrm{\Lambda }\mathrm{SFDM}$ model has $T_{\text{reheat}}\simeq 2\times {10}^4\mathrm{GeV}$ and $m\simeq 1.6\times {10}^{-19}\mathrm{eV}/c^2$, for which we predict an aLIGO O1 run detection with signal-to-noise ratio of $\sim 10$. We show that the null detection of the SGWB recently reported by the aLIGO O1 run excludes the parameter range $8.75\times {10}^3\lesssim T_{\text{reheat}}(\mathrm{GeV})\lesssim 1.7\times {10}^5$ for this illustrative family at 95% confidence, thereby demonstrating that GW detection experiments can already place a new kind of cosmological constraint on SFDM. A wider range of SFDM parameters and reheat temperatures should be accessible to aLIGO/Virgo O5, with the potential to detect this unique signature of the $\mathrm{\Lambda }\mathrm{SFDM}$ model. For this same illustrative family, for example, a $3\sigma$ detection is predicted for $600\lesssim T_{\text{reheat}}(\mathrm{GeV})\lesssim {10}^7$.

We apply three forward light-by-light scattering sum rules to charmonium states. We show that these sum rules imply a cancellation between charmonium bound state contributions, which are mostly known from the $\gamma \gamma$ decay widths of these states, and continuum contributions above $D\overline{D}$ threshold, for which we provide a duality estimate. We also show that two of these sum rules allow us to predict the yet unmeasured ${\gamma }^{*}\gamma$ coupling of the ${\chi }_{c1}(1P)$ state, which can be tested at present high-luminosity $e^{+}{e}^{-}$ colliders.