On Minkowski spacetime, the angular momentum flux through null infinity of Maxwell fields, computed using the stress-energy tensor, depends not only on the radiative degrees of freedom (d.o.f.), but also on the Coulombic parts. However, the angular momentum also can be computed using other conserved currents associated with a Killing field, such as the Noether current and the canonical current. The flux computed using these latter two currents is purely radiative. A priori, it is not clear which of these is to be considered the “true” flux of angular momentum for Maxwell fields. This situation carries over to Maxwell fields on nondynamical, asymptotically flat spacetimes for fluxes associated with the Lorentz symmetries in the asymptotic Bondi-Metzner-Sachs (BMS) algebra. We investigate this question of angular momentum flux in the full Einstein-Maxwell theory. Using the prescription of Wald and Zoupas, we compute the charges associated with any BMS symmetry on cross sections of null infinity. The change of these charges along null infinity then provides a flux. For Lorentz symmetries, Maxwell fields contribute an additional term, compared to the Wald-Zoupas charge in vacuum general relativity, to the charge on a cross section. With this additional term, the flux associated with Lorentz symmetries, e.g., the angular momentum flux, is purely determined by the radiative d.o.f. of the gravitational and Maxwell fields. In fact, the contribution to this flux by Maxwell fields is given by the radiative Noether current flux and not by the stress-energy flux.

We present an alternative derivation of the gravitational clock compass and show how such a device can be used for the detection of gravitational waves. Explicit compass setups are constructed in special types of space-times, namely for exact plane gravitational waves and for waves moving radially relative to an observer.

We derive the one-loop perturbative formula of the redshift-space matter power spectrum after density field reconstruction in the Zeldovich approximation. We find that the reconstruction reduces the amplitudes of nonlinear one-loop perturbative terms significantly by partially erasing the nonlinear mode coupling between density and velocity fields. In comparison with $N$-body simulations, we find that both the monopole and quadrupole spectra of reconstructed matter density fields agree with the one-loop perturbation theory up to higher wave number than those before reconstruction. We also evaluate the impact on cosmic growth rate assuming the survey volume and the number density like the Baryon Oscillation Spectroscopic Survey and find that the total error, including statistical and systematic ones due to one-loop approximation, decreases by half.

The light relic density affects the thermal and expansion history of the early Universe, leaving a number of observable imprints. We focus on the primordial abundances of light elements produced during the process of big bang nucleosynthesis that are influenced by the light relic density. Primordial abundances can be used to infer the density of light relics and thereby serve as a probe of physics beyond the standard model. We calculate the observational uncertainty on primordial light element abundances and associated quantities that would be required in order for these measurements to achieve sensitivity to the light relic density comparable to that anticipated from upcoming cosmic microwave background surveys. We identify the nuclear reaction rates that need to be better measured to maximize the utility of future observations. We show that improved measurements of the primordial helium-4 abundance can improve constraints on light relics, while more precise measurements of the primordial deuterium abundance are unlikely to be competitive with cosmic microwave background measurements of the light relic density.

We describe features that could be observed in the line spectra of relic cosmological particles should quantum nonequilibrium be preserved in their statistics. According to our arguments, these features would represent a significant departure from those of a conventional origin. Among other features, we find a possible spectral broadening that is proportional to the energy resolution of the recording telescope (and so could be much larger than any conventional broadening). Notably, for a range of possible initial conditions we find the possibility of spectral line “narrowing,” whereby a telescope could observe a line that is narrower than it is conventionally able to resolve. We discuss implications for the indirect search for dark matter, with particular reference to some recent controversial spectral lines.

Recently, it was shown that quark matter with only $u$ and $d$ quarks ($ud\mathrm{QM}$) can be the ground state of matter for baryon numbers $A>A_{\min }$ with $A_{\min }\gtrsim 300$. In this paper, we explore $ud$ quark stars ($ud\mathrm{QSs}$) that are composed of $ud\mathrm{QM}$, in the context of the two-families scenario in which $ud\mathrm{QSs}$ and hadronic stars (HSs) can coexist. Distinct signatures are discussed compared to the conventional study regarding strange quark stars (SQSs). We show that the requirements of $A_{\min }\gtrsim 300$ and the most massive compact star observed being a $ud\mathrm{QS}$ together may put stringent constraints on the allowed parameter space of $ud\mathrm{QSs}$. Then, we study the related gravitational-wave probe of the tidal deformability in binary star mergers, including the $ud\mathrm{QS}\text{−}ud\mathrm{QS}$ and $ud\mathrm{QS}\text{−}\mathrm{HS}$ cases. The obtained values of the tidal deformability at 1.4 solar masses and the average tidal deformability are all in good compatibility with the experimental constraints of GW170817. This study points to a new possible interpretation of the GW170817 binary merger event, where $ud\mathrm{QS}$ may be at least one component of the binary system detected.

We present a novel analysis technique for liquid xenon time projection chambers that allows for a lower threshold by relying on events with a prompt scintillation signal consisting of single detected photons. The energy threshold of the LUX dark matter experiment is primarily determined by the smallest scintillation response detectable, which previously required a twofold coincidence signal in its photomultiplier arrays, enforced in data analysis. The technique presented here exploits the double photoelectron emission effect observed in some photomultiplier models at vacuum ultraviolet wavelengths. We demonstrate this analysis using an electron recoil calibration dataset and place new constraints on the spin-independent scattering cross section of weakly interacting massive particles (WIMPs) down to $2.5\mathrm{GeV}/c^2$ WIMP mass using the 2013 LUX dataset. This new technique is promising to enhance light WIMP and astrophysical neutrino searches in next-generation liquid xenon experiments.

Our understanding of the dynamics and the phase structure of dense strong-interaction matter is to a large extent still built on the analysis of low-energy models, such as those of the Nambu–Jona-Lasinio-type model. In this work, we analyze the emergence of the latter class of models at intermediate- and low-energy scales from fundamental quark-gluon interactions. To this end, we study the renormalization group flow of a Fierz-complete set of four-quark interactions and monitor their strength at finite temperature and quark chemical potential. At small quark chemical potential, we find that the scalar-pseudoscalar interaction channel is dynamically rendered most dominant by the gauge degrees of freedom, indicating the formation of a chiral condensate. Moreover, the inclusion of quark-gluon interactions leaves a significant imprint on the dynamics as measured by the curvature of the finite-temperature phase boundary which we find to be in accordance with lattice QCD results. At large quark chemical potential, we then observe that the dominance pattern of the four-quark couplings is changed by the underlying quark-gluon dynamics, without any fine-tuning of the four-quark couplings. In this regime, the scalar-pseudoscalar interaction channel becomes subleading, and the dominance pattern suggests the formation of a chirally symmetric diquark condensate. In particular, our study confirms the importance of explicit $U_{\mathrm{A}}(1)$ breaking for the formation of this type of condensate at high densities.

New measurements of the coherent elastic neutrino-nucleus scattering (CEvNS) are expected to be achieved in the near future by using two neutrino production channels with different energy distributions: the very low energy electron antineutrinos from reactor sources and the muon and electron neutrinos from spallation neutron sources (SNS) with a relatively higher energy. Although precise measurements of this reaction would allow for an improved knowledge of standard and beyond the Standard Model physics, it is important to distinguish the different new contributions to the process. We illustrate this idea by constraining the average neutron root mean square (rms) radius of the scattering material, as a standard physics parameter, together with the nonstandard interactions (NSI) contribution as the new physics formalism. We show that the combination of experiments with different neutrino energy ranges could give place to more robust constraints on these parameters as long as the systematic errors are under control.

Utilizing the Georgi-Machacek model, we study the electroweak symmetry breaking mechanism with extra electroweak symmetry breaking contributions (eEWSB) that are bounded by the Fermi constant and limits from the related collider searches. The eEWSB is helpful to build a different zero temperature vacuum structure from the Standard Model (SM), and therefore leads to different electroweak phase transition patterns at the early Universe. We investigate the collider search prospects and gravitational waves (GW) predictions from the strongly firstly order phase transition (SFOEWPT) in this scenario. The Higgs pair searches at lepton colliders are found to be complementary with the GW searches of the SFOEWPT parameter spaces.

A thermal potential can be defined to facilitate understanding the behavior of quarkonia in quark-gluon plasma. A nonperturbative evaluation of this potential from lattice QCD is difficult, as it involves a real-time correlation function, and has often involved the use of Bayesian analysis, with its associated systematics. In this work we show that using the properties of the static quarkonia thermal correlation functions, one can directly extract a thermal potential for quarkonia from Euclidean Wilson loop data. This leads to a controlled extraction and allows us to judge the suitability of various model potentials.

Like fluctuations, nondiagonal correlators of conserved charges provide a tool for the study of chemical freeze-out in heavy ion collisions. They can be calculated in thermal equilibrium using lattice simulations, and be connected to moments of event-by-event net-particle multiplicity distributions. We calculate them from continuum-extrapolated lattice simulations at ${\mu }_B=0$, and present a finite-${\mu }_B$ extrapolation, comparing two different methods. In order to relate the grand canonical observables to the experimentally available net-particle fluctuations and correlations, we perform a hadron resonance gas model analysis, which allows us to completely break down the contributions from different hadrons. We then construct suitable hadronic proxies for fluctuation ratios, and study their behavior at finite chemical potentials. We also study the effect of introducing acceptance cuts, and argue that the small dependence of certain ratios on the latter allows for a direct comparison with lattice QCD results, provided that the same cuts are applied to all hadronic species. Finally, we perform a comparison for the constructed quantities for experimentally available measurements from the STAR Collaboration. Thus, we estimate the chemical freeze-out temperature to 165 MeV using a strangeness-related proxy. This is a rather high temperature for the use of the hadron resonance gas; thus, further lattice studies are necessary to provide first principle results at intermediate ${\mu }_B$.

We study the nature of the finite-temperature transition of the three-dimensional scalar chromodynamics with $N_f$ flavors. These models are constructed by considering maximally $\mathrm{O}(M)$-symmetric multicomponent scalar models, whose symmetry is partially gauged to obtain $\mathrm{SU}(N_c)$ gauge theories, with a residual nonabelian global symmetry given by $U(N_f)$ for $N_c\ge 3$ and $\mathrm{Sp}(N_f)$ for $N_c=2$, so that $M=2N_c{N}_f$. For $N_f=2$ and for all values of $N_c$ we investigated, $N_c=2$, 3, 4, these systems undergo a continuous finite-temperature transition, which belongs to a universality class related to the global symmetry group of the model. For $N_c=2$, since $\mathrm{Sp}(2)/{\mathbb{Z}}_2=\mathrm{SO}(5)$, it belongs to the O(5) vector universality class. For $N_c\ge 3$, since $\mathrm{SU}(2)/{\mathbb{Z}}_2=\mathrm{SO}(3)$, it belongs to the O(3) vector universality class. For $N_f\ge 3$, the numerical results show evidence of first-order transitions for any $N_c$. These results are in agreement with the predictions obtained by using the effective Landau-Ginzburg-Wilson approach in terms of a gauge-invariant order parameter. Our results indicate that the non-Abelian gauge degrees of freedom are irrelevant at the transition. These conclusions are supported by an analysis of gauge-field dependent correlation functions, that are always short ranged, even at the transition.

A number of proposed extensions of the standard model include new strongly interacting dynamics, in the form of $SU(N)$ gauge fields coupled to various numbers of fermions. Often, these extensions allow $N=3$ as a plausible choice, or even require $N=3$, such as in twin Higgs models, where the new dynamics is a “copy” of QCD. However, the fermion masses in such a sector are typically different from (often heavier than) the ones of real-world QCD, relative to the confinement scale. Many of the strong interaction masses and matrix elements for $SU(3)$ at heavy fermion masses have already been computed on the lattice, typically as a by-product of the approach to the physical point of real QCD. We provide a summary of these relevant results for the phenomenological community.

We discuss how to study $I=0$ quarkonium resonances decaying into pairs of heavy-light mesons using static potentials from lattice QCD. These static potentials can be obtained from a set of correlation functions containing both static and light quarks. As a proof of concept, we focus on bottomonium with relative orbital angular momentum $L_{\overline{Q}Q}=0$ of the $\overline{b}b$ pair corresponding to $J^{PC}=0^{-+}$ and $J^{PC}=1^{--}$. We use static potentials from an existing lattice QCD string breaking study and compute phase shifts and $\mathrm{T}$ matrix poles for the lightest heavy-light meson-meson decay channel. We discuss our results in the context of corresponding experimental results, in particular for $\mathrm{\Upsilon }(10860)$ and $\mathrm{\Upsilon }(11020)$.

In this article, based on the approach of McKeon et al., we show that the renormalization group equation related to the radiative mass scale $\mu$ operates as a summation over QCD perturbative terms. Employing the full QCD $\beta$ function within this summation, all logarithmic corrections can be presented as log-independent contributions. In another step of this approach, the renormalization scheme dependence for QCD observables characterized by Stevenson can be examined by specifying the renormalization scheme, in which the $\beta$ function beyond two-loop order is utilized. In this regard, there are two choices of renormalization scheme. In the first scheme, the QCD observable involves two powers of the running coupling constant, such that the perturbative series contains just two terms. In the second scheme, the perturbative series expansion is written as an infinite series in terms of the two-loop running coupling, which can be represented by the Lambert $W$ function. In both cases, the QCD observable involves parameters that are renormalization scheme invariant and the coupling constant, which is independent of the renormalization scale. We then consider another approach, which is called complete renormalization group improvement (CORGI). In this approach, by using the self-consistency principle it is possible to reconstruct the conventional perturbative series in terms of scheme-invariant quantities and the coupling constant as a function of the Lambert $W$ function. It should be noted that while in the renormalization group summation method of McKeon et al. the scheme dependence of observables is investigated separately from their scale dependence, in the CORGI approach, through the principle of self-consistency, both scale and scheme parameters are utilized. Then, we numerically examine these two approaches, considering two QCD observables. The first is the $R_{e^{+}{e}^{-}}$ ratio, investigated at three different colliding energies, and the second is the Higgs decay width to a gluon pair. We compare our results for $R_{e^{+}{e}^{-}}$ with the available experimental data. The results based on the McKeon et al. approach are in better agreement with the experimental data.

We derive a chiral kinetic theory with Landau level basis, which is valid for slow-varying magnetic field with arbitrary magnitude. We apply the new chiral kinetic theory to calculate the electric conductivity transverse to the magnetic field in a magnetized QED and QCD plasma. Under the lowest Landau level approximation and relaxation time approximation, we find the transverse conductivity is inversely proportional to the relaxation time. We also obtain a frequency-dependent transverse conductivity in response to a time-dependent electric field. We find a high frequency enhancement in this conductivity.

The holographic recipe for the calculation of decay constants is revisited. Starting from the holographic two-point function and using the fact that normalizable bulk modes scale as $z^{\mathrm{\Delta }-S}$, with $S$ the spin, we can obtain a consistent expression that depends on the value of the mode at the boundary, not the derivative. We apply our decay constant expression to other $\mathrm{AdS}/\mathrm{QCD}$ (static and dynamic) models proving its consistency. We also demonstrated that our approach is equivalent to the usual holographic prescription.

We compute the entanglement entropy of a massless spin 2 field in a sphere in flat Minkowski space. We describe the theory with a linearized metric perturbation field $h_{\mu \nu }$ and decompose the field into independent modes using tensor spherical harmonics. We fix the gauge such that (a) the two dynamical modes for each angular momentum decouple and have the dynamics of scalar spherical modes, and (b) the gauge-fixed field degrees of freedom inside the sphere represent gauge invariant operators of the theory localized in the same region. In this way the entanglement entropy turns out to be equivalent to the one of a pair of free massless scalars where the contributions of the $l=0$ and $l=1$ modes have been subtracted. The result for the coefficient of the universal logarithmic term is $-61/45$ and coincides with that computed using a regularization based on the mutual information.

The recently proposed trans-Planckian censorship conjecture (TCC) imposes a strong constraint on the inflationary Hubble scale, of which the upper bound could be largely relaxed by considering a noninstantaneous reheating history. In this paper we will show that, if the primordial black holes (PBHs) are formed at reentry in the radiation-dominated era from the enhanced curvature perturbations at small scales, the TCC would impose a lower bound on the PBH mass $M_{\mathrm{PBH}}>\gamma (H_{\mathrm{end}}/{10}^9\mathrm{GeV}{)}^2{M}_{\odot }$ regardless of the details for reheating history, where $\gamma$ is the collapse efficiency factor and $H_{\mathrm{end}}$ is the Hubble scale at the end of inflation. In particular, the current open window for PBHs to make up all the cold dark matter could be totally ruled out if the inflationary Hubble scale is larger than 10 TeV. For the case of PBHs formed in an early matter-dominated era, an upper mass bound is obtained.