It is an intriguing possibility that dark matter (DM) could have flavor quantum numbers like the quarks. We propose and investigate a class of UV-complete models of this kind, in which the dark matter is in a scalar triplet of an SU(3) flavor symmetry, and interacts with quarks via a colored flavor-singlet fermionic mediator. Such mediators could be discovered at the LHC if their masses are $\sim 1\mathrm{TeV}$. We constrain the DM-mediator couplings using relic abundance, direct detection, and flavor-changing neutral-current considerations. We find that, for reasonable values of its couplings, scalar flavored DM can contribute significantly to the real and imaginary parts of the $B_s-{\overline{B}}_s$ mixing amplitude. We further assess the potential for such models to explain the Galactic center GeV gamma-ray excess.

A dark sector resembling the Standard Model, where the abundance of matter is explained by baryon and lepton asymmetries and stable constituents bind to form atoms, is a theoretically appealing possibility. We show that a minimal model with a hidden SU(2) gauge symmetry broken to U(1), with a Dirac fermion doublet, suffices to realize this scenario. Supplemented with a dark Higgs doublet that gets no vacuum expectation value, we readily achieve the dark matter asymmetry through leptogenesis. The model can simultaneously have three portals to the Standard Model, through the Higgs, non-Abelian kinetic mixing, and the heavy neutrino, with interesting phenomenology for direct and collider searches, as well as cosmologically relevant dark matter self-interactions. Exotic bound states consisting of two fermions and a doubly charged vector boson can exist in one phase of the theory.

In recent years, the use of variational analysis techniques in lattice QCD has been demonstrated to be successful in the investigation of the rest-mass spectrum of many hadrons. However, due to parity mixing, more care must be taken for investigations of boosted states to ensure that the projected correlation functions provided by the variational analysis correspond to the same states at zero momentum. In this paper we present the parity-expanded variational analysis (PEVA) technique, a novel method for ensuring the successful and consistent isolation of boosted baryons through a parity expansion of the operator basis used to construct the correlation matrix.

We construct a nonrelativistic effective field theory description of heavy quarkonium hybrids from QCD. We identify the symmetries of the system made of a heavy quark, a heavy antiquark, and glue in the static limit. Corrections to this limit can be obtained order by order in an expansion in the inverse of the mass $m$ of the heavy quark. At order $1/m$ in the expansion, we obtain, at the level of potential nonrelativistic QCD, a system of coupled Schrödinger equations that describes hybrid spin-symmetry multiplets, including the mixing of different static energies into the hybrid states, an effect known as $\mathrm{\Lambda }$ doubling in molecular physics. In the short distance, the static potentials depend on two nonperturbative parameters, the gluelump mass and the quadratic slope, which can be determined from lattice calculations. We adopt a renormalon subtraction scheme for the calculation of the perturbative part of the potential. We numerically solve the coupled Schrödinger equations and obtain the masses for the lowest lying spin-symmetry multiplets for $c\overline{c}$, $b\overline{c}$, and $b\overline{b}$ hybrids. The $\mathrm{\Lambda }$-doubling effect breaks the degeneracy between opposite-parity spin-symmetry multiplets and lowers the mass of the multiplets that get mixed contributions of different static energies. We compare our findings to the experimental data, direct lattice computations, and sum rule calculations, and discuss the relation to the Born-Oppenheimer approximation.

The decay $D^0\to {\pi }^{+}{\pi }^{-}{\pi }^0$ appears to be dominated by $\rho \pi$ states in a configuration of zero total isotopic spin. The spin $J$, parity $P$, and charge-conjugation eigenvalue $C$ of this final state are, therefore, $J^{PC}=0^{--}$, which cannot be formed of a quark $q$ and antiquark $\overline{q}$. If a resonance near $M(D^0)$ dominates the final state, it must be a hybrid composed of a quark-antiquark pair and a constituent gluon, or a tetraquark $qq\overline{q}\overline{q}$. A test for this resonance in electroproduction is proposed.

We present measurements of the frequency dependence of thermal noise in aluminum and niobium flexures. Our measurements cover the audio-frequency band from 10 Hz to 10 kHz, which is of particular relevance to ground-based interferometric gravitational wave detectors, and span up to an order of magnitude above and below the fundamental flexure resonances. Results from two flexures are well explained by a simple model in which both structural and thermoelastic loss play a role. The ability of such a model to explain this interplay is important for investigations of quantum-radiation-pressure noise and the standard quantum limit. Furthermore, measurements on a third flexure provide evidence that surface damage can affect the frequency dependence of thermal noise in addition to reducing the quality factor, a result which will aid the understanding of how aging effects impact on thermal noise behavior.

We investigate the low transverse momentum heavy quarkonium ($J/\psi$, $\mathrm{\Upsilon }$) productions in the forward rapidity region of $pp$ and $pA$ collisions at the LHC as an important probe to the transverse momentum tomography of the gluons in hadrons in the color glass condensate (CGC) framework. By implementing the Sudakov resummation consistently in the CGC formalism, we achieve an excellent agreement between the improved CGC calculations and the LHC data. We show that both the small-$x$ and the Sudakov effects are essential for a complete description of heavy quarkonium productions in the low transverse momentum region. This provides a solid foundation to study the small-$x$ gluon saturation in a big nucleus with the future $pA$ programs at the LHC.

We study quenched disorder in strongly correlated systems via holography, focusing on the thermodynamic effects of mild electric disorder. Disorder is introduced through a random potential which is assumed to self-average on macroscopic scales. Studying the flow of this distribution with energy scale leads us to develop a holographic functional renormalization scheme. We test this scheme by computing thermodynamic quantities and confirming that the Harris criterion for relevance, irrelevance, or marginality of quenched disorder holds.

We consider several configurations that describe Wilson loops in nonrelativistic field theories, and for some of them we find systems of coupled nonlinear differential equations. Also, we find a nontrivial drag force at zero temperature, which suggests that the parameter controlling the deviation of the nonrelativistic space from the relativistic space may be related to the chemical potential of these systems. Moreover, we reconsider some known configurations in the literature and we perform further analysis.

We study implications of the weak gravity conjecture in the AdS/CFT correspondence. Unlike in Minkowski spacetime, Anti-de Sitter (AdS) spacetime has a physical length scale, so that the conjecture must be generalized with an additional parameter. We discuss possible generalizations and translate them into the language of dual conformal field theories (CFTs), which take the form of inequalities involving the dimension and charge of an operator as well as the current and energy-momentum tensor central charges. We then test these inequalities against various CFTs to see if they are universally obeyed by all the CFTs. We find that certain CFTs, such as supersymmetric QCDs, do not satisfy them even in the large $N$ limit. This does not contradict the conjecture in AdS spacetime because the theories violating them are either unlikely or unclear to have weakly coupled gravitational descriptions, but it suggests that the CFT inequalities obtained here by naive translations do not apply beyond the regime in which weakly coupled gravitational descriptions are available.

The quark production in classical color fields is investigated with a focus on the induction of an electromagnetic current by produced quarks. We show that the color SU(2) and the SU(3) theories lead significantly different results for the electromagnetic current. In uniform SU(2) color fields, the net electromagnetic current is not generated, while in SU(3) color fields the net current is induced depending on the color direction of background fields. Also the numerical study of the quark production in inhomogeneous color fields is done. Motivated by gauge field configurations provided by the color glass condensate framework, we introduce an ensemble of randomly distributed color electric fluxtubes. The spectrum of photons emitted from the quarks by a classical process is shown.

Primordial black holes are studied in the Bose-Einstein condensate description of space-time. The question of baryon-number conservation is investigated with emphasis on the possible formation of bound states of the system’s remaining captured baryons. This leads to distinct predictions both for the formation time, which for the naively natural assumptions is shown to lie between ${10}^{-12}\mathrm{s}$ and ${10}^{12}\mathrm{s}$ after the big bang, and for the remnant’s mass, yielding approximately $3\times {10}^{23}\mathrm{kg}$ in the same scheme. The consequences for astrophysically formed black holes are also considered.

We study how a cosmological bounce, with a type IV singularity at the bouncing point, can be generated by a classical vacuum $F(G)$ gravity. We focus our investigation on the behavior of the vacuum $F(G)$ theory near the type IV singular bouncing point and address the stability of the resulting solution by treating the equations of motion as a dynamical system. In addition, we investigate how the scalar perturbations of the background metric evolve, emphasizing cosmological times near the type IV singular bouncing point. Finally, we also investigate which mimetic vacuum $F(G)$ gravity can describe the singular bounce cosmology.

We derive constraints on cosmological parameters and tests of dark energy models from the combination of baryon acoustic oscillation (BAO) measurements with cosmic microwave background (CMB) data and a recent reanalysis of Type Ia supernova (SN) data. In particular, we take advantage of high-precision BAO measurements from galaxy clustering and the Lyman-$\alpha$ forest (LyaF) in the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). Treating the BAO scale as an uncalibrated standard ruler, BAO data alone yield a high confidence detection of dark energy; in combination with the CMB angular acoustic scale they further imply a nearly flat universe. Adding the CMB-calibrated physical scale of the sound horizon, the combination of BAO and SN data into an “inverse distance ladder” yields a measurement of $H_0=67.3\pm 1.1\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$, with 1.7% precision. This measurement assumes standard prerecombination physics but is insensitive to assumptions about dark energy or space curvature, so agreement with CMB-based estimates that assume a flat $\mathrm{\Lambda }\mathrm{CDM}$ cosmology is an important corroboration of this minimal cosmological model. For constant dark energy ($\mathrm{\Lambda }$), our $\mathrm{BAO}+\mathrm{SN}+\mathrm{CMB}$ combination yields matter density ${\mathrm{\Omega }}_m=0.301\pm 0.008$ and curvature ${\mathrm{\Omega }}_k=-0.003\pm 0.003$. When we allow more general forms of evolving dark energy, the $\mathrm{BAO}+\mathrm{SN}+\mathrm{CMB}$ parameter constraints are always consistent with flat $\mathrm{\Lambda }\mathrm{CDM}$ values at $\approx 1\sigma$. While the overall ${\chi }^2$ of model fits is satisfactory, the LyaF BAO measurements are in moderate ($2–2.5\sigma$) tension with model predictions. Models with early dark energy that tracks the dominant energy component at high redshift remain consistent with our expansion history constraints, and they yield a higher $H_0$ and lower matter clustering amplitude, improving agreement with some low redshift observations. Expansion history alone yields an upper limit on the summed mass of neutrino species, $\sum m_{\nu }<0.56\mathrm{eV}$ (95% confidence), improving to $\sum m_{\nu }<0.25\mathrm{eV}$ if we include the lensing signal in the Planck CMB power spectrum. In a flat $\mathrm{\Lambda }\mathrm{CDM}$ model that allows extra relativistic species, our data combination yields $N_{\mathrm{eff}}=3.43\pm 0.26$; while the LyaF BAO data prefer higher $N_{\mathrm{eff}}$ when excluding galaxy BAO, the galaxy BAO alone favor $N_{\mathrm{eff}}\approx 3$. When structure growth is extrapolated forward from the CMB to low redshift, standard dark energy models constrained by our data predict a level of matter clustering that is high compared to most, but not all, observational estimates.

From data recently reported from the IceCube telescope, we derive new bounds on the monochromatic neutrino signal produced from dark matter particle decays. In the few TeV to tens of TeV energy range, these bounds turn out to be better than previous limits by more than an order of magnitude. As a result, intensity constraints on neutrino lines at energies above a few TeV are now comparable to those on gamma-ray lines. From the same data sample, we also perform a detailed search for a neutrino line, showing that there is no significant hint for such a signal.

We improve previous calculations of the cosmic microwave background spectral distortions due to the decay of primordial magnetic fields. We focus our studies on causally generated magnetic fields at the electroweak and QCD phase transitions. We also consider the decay of helical magnetic fields. We show that the decay of nonhelical magnetic fields generated at either the electroweak or QCD scale produce $\mu$- and $y$-type distortions below ${10}^{-8}$ which are probably not detectable by a future PIXIE-like experiment. We show that magnetic fields generated at the electroweak scale must have a helicity fraction $f_{*}>10^{-4}$ in order to produce detectable $\mu$-type distortions. Hence, a positive detection coming from the decay of magnetic fields would rule out nonhelical primordial magnetic fields and provide a lower bound on the magnetic helicity.

Within the context of the $\mathrm{AdS}/\mathrm{CFT}$ correspondence, we show that the DC thermoelectric conductivity can be obtained by solving the linearized, time-independent, and forced Navier-Stokes equations on the black hole horizon for an incompressible and charged fluid.

We investigate the impact of the matter and glue dynamics on baryon number fluctuations and the kurtosis of baryon number distribution. This is done within the framework of QCD-improved low-energy effective models. In particular, we include the momentum scale dependence of the quark-meson scattering and the nontrivial dispersions of both quarks and mesons. On the gluonic side, we take into account the backreaction of the matter sector on the glue dynamics. It is shown that the above fluctuations lead to a more rapid change of the baryon number fluctuations as well as the kurtosis of with the chiral crossover. We also study the signatures of quark confinement in low-energy QCD. It is shown that, contrary to the common picture, the effective thermal distribution in the presence of confining glue backgrounds does not tend towards the colorless baryonic one. Instead, the dominance of colorless hadronic states is obtained in a subtle interplay of quark and glue contributions to the canonical potential.