We obtain the nonequilibrium effective action of an inflatonlike scalar field—the system—by tracing over sub-Hubble degrees of freedom of “environmental” light scalar fields. The effective action is stochastic leading to effective Langevin equations of motion for the fluctuations of the inflatonlike field, with self-energy corrections and stochastic noise correlators that obey a de Sitter space-time analog of a fluctuation dissipation relation. We solve the Langevin equation implementing a dynamical renormalization group resummation of the leading secular terms and obtain the corrections to the power spectrum of super-Hubble fluctuations of the inflaton field, $\mathcal{P}(k;\eta )={\mathcal{P}}_0(k)e^{-\gamma (k;\eta )}$ where ${\mathcal{P}}_0(k)$ is the nearly scale invariant power spectrum in absence of coupling. $\gamma (k;\eta )>0$ describes the suppression of the power spectrum; it features Sudakov-type double logarithms and entails violations of scale invariance. We also obtain the effective action for the case of a heavy scalar field of mass $M\gg H$; this case yields a local “Fermi” limit with a very weak self-interaction of the inflatonlike field and dissipative terms that are suppressed by powers of $H/M$. We conjecture on the possibility that the large scale anomalies in the cosmic microwave background may originate in dissipative processes from inflaton coupling to sub-Hubble degrees of freedom.

We develop a model to study tetraquark production in hadronic collisions. We focus on double parton scattering and formulate a version of the color evaporation model for the production of the $X(3872)$ and of the $T_{4c}$ tetraquark, a state composed by the $c\overline{c}c\overline{c}$ quarks. We find that the production cross section grows rapidly with the collision energy $\sqrt{s}$ and make predictions for the forthcoming higher energy data of the LHC.

We consider the production of dark matter in association with a pair of top quarks, mediated by a scalar or pseudoscalar particle in a generic Simplified Model. We demonstrate that the difference of azimuthal angle between the two leptons $\mathrm{\Delta }{\varphi }_{\ell \ell }$, in the dileptonic top decay mode, can directly probe the $CP$-properties of the mediator. We estimate the constraints to strength and $CP$-structure of dark matter production for these well-motivated Simplified Models from the LHC Run II.

We investigate the special case of quintic interactions for massless higher spin gauge fields using the string-theoretic vertex operator construction for higher spin gauge fields in Vasiliev’s framelike formalism. We compute explicitly the related five-point interaction vertex in the low energy limit of string theory and find that the structure of the quintic $s_1-s_2-s_3-s_4-s_5$ higher spin interaction gets drastically simplified and localized if (a) the spin values satisfy the constraint $s_1+s_2+s_3=s_4+s_5+2$ (and, more generally, if the sum of three spin values roughly equals the sum of the remaining two) and (b) one of the spin values $s_4$ or $s_5$ is sufficiently small. In this paper, the explicit computation is done for the case $s_4=4$.

We study the cosmic censorship of dynamical $p$-brane systems in a $D$-dimensional background. This is the generalization of the analysis in the Einstein-Maxwell-dilaton theory, which was discussed by Horne and Horowitz [Phys. Rev. D 48, R5457 (1993)]. We show that a timelike curvature singularity generically appears from an asymptotic region in the time evolution of the $p$-brane solution. Since we can set regular and smooth initial data in a dynamical M5-brane system in 11-dimensional supergravity, this implies a violation of cosmic censorship.

We explore the tensor perturbation of the $f(T)$ brane embedded in an ${\mathrm{AdS}}_5$ spacetime. With the transverse-traceless condition, we get the tensor perturbation equation of the $f(T)$ brane and show that the stability of this brane system can be ensured. In addition, we take $f(T)=T+\alpha T^2$ as an example to analyze the localization problem of the graviton zero mode. It is shown that the graviton zero mode can be localized on the brane.

We derive the structure of the density matrix for two Unruh-DeWitt detectors coupled to a massless scalar field to all orders of perturbation theory, in spacetimes admitting a well-defined Wightman function. Calculating all of its leading terms enables us to fully characterize observable correlations, entanglement, and quantum discord. We apply these results to study detector responses in two locally flat topologically nontrivial spacetimes constructed from identifications of Minkowski space. We demonstrate how local statistics and detector-detector correlations depend on the global spacetime structure. In particular, we show that if the spacetime has a preferred direction, this direction may be inferred from the dependence of correlations between the two detectors on their orientation. While using such measurements to distinguish spacetimes with identical local geometry is apparently impractical, this effect points to fundamental connections between quantum field correlations and the structure of spacetime. This relationship may also be relevant in the phenomenology of the early Universe.

A parametric reconstruction of the jerk parameter, the third order derivative of the scale factor expressed in a dimensionless way, has been discussed. Observational constraints on the model parameters have been obtained by maximum likelihood analysis of the models using supernova distance modulus data, observational Hubble data, baryon acoustic oscillation data, and cosmic microwave background shift parameter data. The present value of the jerk parameter has been kept open to start with, but the plots of various cosmological parameters, like deceleration parameter $q(z)$, jerk parameter $j(z)$, and dark energy equation of state parameter $w_{\mathrm{DE}}(z)$ indicate that the reconstructed models are very close to a $\mathrm{\Lambda }\mathrm{CDM}$ model with a slight inclination toward a nonphantom behavior of the evolution.

Gamma rays and neutrinos are produced as a result of proton-proton interactions that occur in different astrophysical contexts. The detection of these two types of messengers is of great importance for the study of different physical phenomena, related to nonthermal processes, taking place in different astrophysical scenarios. Therefore, the knowledge of the energy spectrum of these two types of particles, as a function of the incident proton energy, is essential for the interpretation of the observational data. In this paper, parametrizations of the energy spectra of gamma rays and neutrinos, originated in proton-proton collisions, are presented. The energy range of the incident protons considered extends from ${10}^2$ to ${10}^8\mathrm{GeV}$. The parametrizations are based on Monte Carlo simulations of proton-proton interactions performed with the hadronic interaction models QGSJET-II-04 and EPOS-LHC, which have recently been updated with the data taken by the Large Hadron Collider.

We report the measurement of muons and muon-induced phosphorescence in DM-Ice17, a NaI(Tl) direct detection dark matter experiment at the South Pole. Muon interactions in the crystal are identified by their observed pulse shape and large energy depositions. The measured muon rate in DM-Ice17 is $2.93\pm 0.04\mu /\text{crystal}/\text{day}$ with a modulation amplitude of $12.3\pm 1.7\%$, consistent with expectation. Following muon interactions, we observe long-lived phosphorescence in the NaI(Tl) crystals with a decay time of $5.5\pm 0.5\mathrm{s}$. The prompt energy deposited by a muon is correlated to the amount of delayed phosphorescence, the brightest of which consist of tens of millions of photons. These photons are distributed over tens of seconds with a rate and arrival timing that do not mimic a scintillation signal above $2{\mathrm{keV}}_{\mathrm{ee}}$. While the properties of phosphorescence vary among individual crystals, the annually modulating signal observed by DAMA cannot be accounted for by phosphorescence with the characteristics observed in DM-Ice17.

We describe a minimal extension of the standard model (SM) by three right-handed neutrinos, a scalar doublet, and a scalar singlet (the “$\nu \mathrm{DFSZ}$”) which serves as an existence proof that weakly coupled high-scale physics can naturally explain phenomenological shortcomings of the SM. The $\nu \mathrm{DFSZ}$ can explain neutrino masses, baryogenesis, the strong $CP$ problem, and dark matter, and remains calculably natural despite a hierarchy of scales up to $\sim {10}^{11}\mathrm{GeV}$. It predicts a SM-like Higgs boson (maximally) TeV-scale scalar states, intermediate-scale hierarchical leptogenesis (${10}^5\mathrm{GeV}\lesssim M_N\lesssim {10}^7\mathrm{GeV}$), and axionic dark matter.

A new transient effective theory of the relativistic Boltzmann equation is derived for locally momentum-anisotropic systems. In the expansion of the distribution function around a local “quasi-equilibrium” state, a nonhydrodynamic dynamical degree of freedom is introduced at leading order that breaks local momentum isotropy. By replacing the deviation of the distribution function from this quasi-equilibrium state in terms of moments of the leading-order distribution and applying a systematic power-counting scheme that orders the nonhydrodynamic modes by their microscopic time scales, a closed set of equations for the dynamical degrees of freedom is obtained. Truncating this set at the level of the slowest nonhydroynamic mode, we find that it exhibits transient oscillatory behavior—a phenomenon previously found only in strongly coupled theories, where it appears to be generic. In weakly coupled systems described by the Boltzmann equation, these transient oscillations depend on the breaking of local momentum isotropy being treated nonperturbatively at leading order in the expansion of the distribution function.

$e^{+}{e}^{-}\to W^{+}{W}^{-}$ is an integral part of the global precision analysis program which is becoming more relevant after the discovery of the Higgs boson. We analyze the current situation of precision calculations of inclusive $e^{+}{e}^{-}\to W^{+}{W}^{-}$ observables and study the prospects of incorporating them into the framework of global precision electroweak analyses in light of per-mil-level cross section measurements at proposed future facilities. We present expansion formulas for the observables, making the dependence on the inputs clear. Also, the calculation of new physics effects is demonstrated in the effective field theory framework for universal theories. We go beyond the triple-gauge-couplings parametrization and illustrate the complementarity of $e^{+}{e}^{-}\to W^{+}{W}^{-}$ and other precision data at the observables level.

Relying on an effective-string approach in which glueballs—bound states of pure Yang-Mills theory—are modeled by closed strings, we give arguments suggesting that anyonic glueballs, i.e. glueballs with arbitrary spin, may exist in ($2+1$)-dimensional Yang-Mills theory. We then focus on the large-$N_c$ limit of $SU(N_c)$ Yang-Mills theory and show that our model leads to a mass spectrum in good agreement with lattice data in the scalar sector, while it predicts the masses and spins of anyonic glueball states.

We formulate several criteria under which the symmetries associated with the Killing and Killing-Yano tensors on the base space can be lifted to the symmetries of the full warped geometry. The procedure is explicitly illustrated on several examples, providing new prototypes of spacetimes admitting such tensors. In particular, we study a warped product of two Kerr-NUT-(A)dS spacetimes and show that it gives rise to a new class of highly symmetric vacuum (with a cosmological constant) black hole solutions that inherit many of the properties of the Kerr-NUT-(A)dS geometry.

We study spacetimes that lead to a separable Klein-Gordon equation in a general number of dimensions. We introduce an ansatz for the metric in higher dimensions motivated by analogical work by Carter in four dimensions and find solutions of the Klein-Gordon equation. For such a metric we solve the Einstein equations and regain the Kerr–NUT–(A)dS spacetime as one of our results. Other solutions lead to the Einstein-Kähler metric of a Euclidean signature. Next we investigate a warped geometry of two Klein-Gordon separable spaces with a properly chosen warped factor. We show that the resulting metric leads also to a separable Klein-Gordon equation and we find the corresponding solutions. Finally, we solve the Einstein equations for the warped geometry and obtain new solutions.

The discrepancy between the amplitudes of matter fluctuations inferred from Sunyaev-Zel’dovich (SZ) cluster number counts and the measurement of temperature and polarization anisotropies of the cosmic microwave background (CMB) measured by the Planck satellite can be reconciled if the local universe is embedded in an underdense region as shown by Lee, 2014. Here using a simple void model assuming the open Friedmann-Robertson-Walker geometry and a Markov Chain Monte Carlo technique, we investigate how deep the local underdense region needs to be to resolve this discrepancy. Such local void, if it exists, predicts the local Hubble parameter value that is different from the global Hubble constant. We derive the posterior distribution of the local Hubble parameter from a joint fitting of the Planck CMB data and SZ cluster number counts assuming the simple void model. We show that the predicted local Hubble parameter value of $H_{\text{loc}}=70.1\pm 0.34\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ is in better agreement with direct local Hubble parameter measurements, indicating that the local void model may provide provide a consistent solution to the cluster number counts and Hubble parameter discrepancies.

We propose the addition of a new “soft-collinear” mode to soft collinear effective theory (SCET) below the usual soft scale to factorize and resum logarithms of jet radii $R$ in jet cross sections. We consider exclusive 2-jet cross sections in $e^{+}{e}^{-}$ collisions with an energy veto $\mathrm{\Lambda }$ on additional jets. The key observation is that there are actually two pairs of energy scales whose ratio is $R$: the transverse momentum $QR$ of the energetic particles inside jets and their total energy $Q$, and the transverse momentum $\mathrm{\Lambda }R$ of soft particles that are cut out of the jet cones and their energy $\mathrm{\Lambda }$. The soft-collinear mode is necessary to factorize and resum logarithms of the latter hierarchy. We show how this factorization occurs in the jet thrust cross section for cone and $k_T$-type algorithms at $\mathcal{O}({\alpha }_s)$ and using the thrust cone algorithm at $\mathcal{O}({\alpha }_s^2)$. We identify the presence of hard-collinear, in-jet soft, global (veto) soft, and soft-collinear modes in the jet thrust cross section. We also observe here that the in-jet soft modes measured with thrust are actually the “csoft” modes of the theory ${\mathrm{SCET}}_{+}$. We dub the new theory with both csoft and soft-collinear modes “${\mathrm{SCET}}_{++}$.” We go on to explain the relation between the “unmeasured” jet function appearing in total exclusive jet cross sections and the hard-collinear and csoft functions in measured jet thrust cross sections. We do not resum logs that are nonglobal in origin, arising from the ratio of the scales of soft radiation whose thrust is measured at $Q\tau /R$ and of the soft-collinear radiation at $2\mathrm{\Lambda }R$. Their resummation would require the introduction of additional operators beyond those we consider here. The steps we outline here are a necessary part of summing logs of $R$ that are global in nature and have not been factorized and resummed beyond leading-log level previously.

We study the moduli space of (framed) self-dual instantons on $\mathbb{C}{P}^2$. These are described by an Atiyah-Drinfeld-Hitchin-Manin (ADHM)-like construction which allows us to compute the Hilbert series of the moduli space. The latter has been found to be blind to certain compact directions. In this paper, we probe these, finding them to correspond to a Grassmanian, upon considering appropriate ungaugings. Moreover, the ADHM-like construction can be embedded into a $3d$ gauge theory with a known gravity dual. Using this, we realize in ${\mathrm{AdS}}_4/{\mathrm{CFT}}_3$ (part of), the instanton moduli space providing at the same time further evidence supporting the ${\mathrm{AdS}}_4/{\mathrm{CFT}}_3$ duality. Moreover, upon orbifolding, we provide the ADHM-like construction of instantons on $\mathbb{C}{P}^2/{\mathbb{Z}}_n$ as well as compute its Hilbert series. As in the unorbifolded case, these turn out to coincide with those for instantons on ${\mathbb{C}}^2/{\mathbb{Z}}_n$.

We study the propagator of a colored scalar particle in the background of a non-Abelian gauge field using the worldline formalism. It is obtained by considering the open worldline of a scalar particle with extra degrees of freedom needed to take into account the color charge of the particle, which we choose to be in the fundamental representation of the gauge group. Specializing the external gauge field to be given by a sum of plane waves, i.e. a sum of external gluons, we produce a master formula for the scalar propagator with an arbitrary number of gluons directly attached to the scalar line, akin to similar formulas derived in the literature for the case of the scalar particle performing a loop. Our worldline description produces at the same time the situation in which the particle has a color charge given by an arbitrarily chosen symmetric or antisymmetric tensor product of the fundamental.