We propose a novel approach to probe new fundamental interactions using isotope shift spectroscopy in atomic clock transitions. As a concrete toy example we focus on the Higgs boson couplings to the building blocks of matter: the electron and the up and down quarks. We show that the attractive Higgs force between nuclei and their bound electrons, which is poorly constrained, might induce effects that are larger than the current experimental sensitivities. More generically, we discuss how new interactions between the electron and the neutrons, mediated via light new degrees of freedom, may lead to measurable nonlinearities in a King plot comparison between isotope shifts of two different transitions. Given state-of-the-art accuracy in frequency comparison, isotope shifts have the potential to be measured with sub-Hz accuracy, thus potentially enabling the improvement of current limits on new fundamental interactions. A candidate atomic system for this measurement requires two different clock transitions and four zero nuclear spin isotopes. We identify several systems that satisfy this requirement and also briefly discuss existing measurements. We consider the size of the effect related to the Higgs force and the requirements for it to produce an observable signal.

We present the first study of the QCD corrections to the color-singlet (CS) $J/\psi$ production in deeply inelastic $ep$ scattering at HERA. The $K$-factor ranges from 0.85 to 2.38 in the kinematic regions we study. In low transverse momentum regions, the $K$-factors is even smaller, and close to 1, which indicates good convergence of the perturbative expansion. With the QCD corrections, the CS cross section is still below the data. At least at QCD next-to-leading order, the color-octet mechanism is necessary to describe the data.

Using the Belle data on the decay $\mathrm{\Upsilon }(10860)\to \mathrm{\Upsilon }(1S)f_0(980)\to \mathrm{\Upsilon }(1S){\pi }^{+}{\pi }^{-}$, we estimate the fraction of the process $\mathrm{\Upsilon }(10860)\to \mathrm{\Upsilon }(1S)f_0(980)\to \mathrm{\Upsilon }(1S)\eta {\pi }^0$, caused by the mixing of $a_0^0(980)$ and $f_0(980)$ resonances that breaks the isotopic invariance due to the $K^{+}$ and $K^0$ meson mass difference. With an instantaneous luminosity of $8\times {10}^{35}{\mathrm{cm}}^{-2}·{\mathrm{s}}^{-1}$ at the SuperKEKB collider, one can collect with the Belle II detector about a hundred $\mathrm{\Upsilon }(10860)\to \mathrm{\Upsilon }(1S)\eta {\pi }^0$ events in the narrow region of the $\eta {\pi }^0$ invariant mass near the $K\overline{K}$ thresholds in a time roughly spent on the present Belle experiment.

We calculate the holographic entanglement entropy for the holographic QCD phase diagram considered in [J. Knaute, R. Yaresko, and B. Kämpfer, arXiv:1702.06731] and explore the resulting qualitative behavior over the temperature-chemical potential plane. In agreement with the thermodynamic result, the phase diagram exhibits the same critical point as the onset of a first-order phase transition curve. We compare the phase diagram of the entanglement entropy to that of the thermodynamic entropy density and find a striking agreement in the vicinity of the critical point. Thus, the holographic entanglement entropy qualifies us to characterize different phase structures. The scaling behavior near the critical point is analyzed through the calculation of critical exponents.

We analyze light vector and scalar meson mass spectra using a novel approach where a modified soft wall model with a UV cutoff is considered. Including this cutoff introduces an extra energy scale. For this model, we found that the masses for the scalar and vector spectra are well fitted within a very small root mean square (RMS) error for 14 of these states, with nonlinear trajectories given by two common parameters, the UV locus $z_0$, and the quadratic dilaton profile slope $\kappa$. We concluded that in this model the $f_0(500)$ scalar resonance cannot be fitted holographically as a $q\overline{q}$ state since we could not find a trajectory that included this pole. This result is in agreement with the most recent phenomenological and theoretical methods.

A recent analysis by one of the authors [L. Perivolaropoulos, Phys. Rev. D 95, 084050 (2017)] has indicated the presence of a $2\sigma$ signal of spatially oscillating new force residuals in the torsion balance data of the Washington experiment. We extend that study and analyze the data of the Stanford Optically Levitated Microsphere Experiment (SOLME) [A. D. Rider et al., Phys. Rev. Lett. 117, 101101 (2016)] (kindly provided by A. D. Rider et al.) searching for sub-mm spatially oscillating new force signals. We find a statistically significant oscillating signal for a force residual of the form $F(z)=\alpha \cos (\frac{2\pi }{\lambda }z+c)$ where $z$ is the distance between the macroscopic interacting masses (levitated microsphere and cantilever). The best fit parameter values are $\alpha =(1.1\pm 0.4)\times {10}^{-17}N$, $\lambda =(35.2\pm 0.6)\mu \mathrm{m}$. Monte Carlo simulation of the SOLME data under the assumption of zero force residuals has indicated that the statistical significance of this signal is at about $2\sigma$ level. The improvement of the ${\chi }^2$ fit compared to the null hypothesis (zero residual force) corresponds to $\mathrm{\Delta }{\chi }^2=13.1$. There are indications that this previously unnoticed signal is indeed in the data but is most probably induced by a systematic effect caused by diffraction of non-Gaussian tails of the laser beam. Thus the amplitude of this detected signal can only be useful as an upper bound to the amplitude of new spatially oscillating forces on sub-mm scales. In the context of gravitational origin of the signal emerging from a fundamental modification of the Newtonian potential of the form $V_{\mathrm{eff}}(r)=-G\frac{M}{r}(1+{\alpha }_O\cos (\frac{2\pi }{\lambda }r+\theta ))\equiv V_N(r)+V_{\mathrm{osc}}(r)$, we evaluate the source integral of the oscillating macroscopically induced force. If the origin of the SOLME oscillating signal is systematic, the parameter ${\alpha }_O$ is bounded as ${\alpha }_O<{10}^7$ for $\lambda \simeq 35\mu \mathrm{m}$. Thus, the SOLME data cannot provide useful constraints on the modified gravity parameter ${\alpha }_O$. However, the constraints on the general phenomenological parameter $\alpha$ ($\alpha <0.3\times {10}^{-17}N$ at $2\sigma$) can be useful in constraining other fifth force models related to dark energy (chameleon oscillating potentials etc.).

Private communication with the authors of [2].

We introduce a frequency-dependent Doppler and aberration transformation kernel for the harmonic multipoles of a general cosmological observable with spin weight $s$, Doppler weight $d$ and arbitrary frequency spectrum. In the context of cosmic microwave background (CMB) studies, the frequency-dependent formalism allows to correct for the motion-induced aberration and Doppler effects on individual frequency maps with different masks. It also permits to deboost background radiations with non-blackbody frequency spectra, like extragalactic foregrounds and CMB spectra with primordial spectral distortions. The formalism can also be used to correct individual E and B polarization modes and account for motion-induced E/B mixing of polarized observables with $d\ne 1$ at different frequencies. We apply the generalized aberration kernel on polarized and unpolarized specific intensity at 100 and 217 GHz and show that the motion-induced effects typically increase with the frequency of observation. In all-sky CMB experiments, the frequency-dependence of the motion-induced effects for a blackbody spectrum are overall negligible. However in a cut-sky analysis, ignoring the frequency dependence can lead to percent level error in the polarized and unpolarized power spectra over all angular scales. In the specific cut-sky used in our analysis ($b>45°,f_{\mathrm{sky}}\simeq 14\%$), and for the dipole-inferred velocity $\beta =0.00123$ typically attributed to our peculiar motion, the Doppler and aberration effects can change polarized and unpolarized power spectra of specific intensity in the CMB rest frame by $1–2\%$, but we find the polarization cross-leakage between E and B modes to be negligible.

We extend the confined isospin-density-dependent mass (CIDDM) model to include temperature dependence of the equivalent mass for quarks. Within the CIDDM model, we study the equation of state for $\beta$-equilibrium quark matter, quark symmetry energy, quark symmetry free energy, and the properties of quark stars at finite temperatures. We find that including the temperature dependence of the equivalent mass can significantly influence the properties of the strange quark matter as well as the quark symmetry energy, the quark symmetry free energy, and the maximum mass of quark stars at finite temperatures. The mass-radius relations for different stages of the protoquark stars (PQSs) along the star evolution are analyzed. Our results indicate that the heating (cooling) process for PQSs will increase (decrease) the maximum mass within the CIDDM model by including temperature dependence of the equivalent mass for quarks.

We investigate the texture structures of lepton mass matrices with four (five) nonzero elements in the charged lepton mass matrix and three (four) vanishing cofactors in the neutrino mass matrix. Using weak basis transformations, all possible textures for three and four vanishing cofactors in $M_{\nu }$ are grouped into seven classes, and predictions for the unknown parameters—such as the Dirac $CP$-violating phase and the effective Majorana mass—for the phenomenologically allowed textures are obtained. We, also, illustrate how such texture structures can be realized using discrete Abelian flavor symmetries.

If the QCD axion is a significant component of dark matter, and if the Universe was once hotter than a few hundred MeV, the axion relic abundance depends on the function $\chi (T)$, the temperature-dependent topological susceptibility. Uncertainties in this quantity induce uncertainties in the axion mass as a function of the relic density, or vice versa. At high temperatures, theoretical uncertainties enter through the dilute instanton gas computation, while in the intermediate and strong coupling regime, only lattice QCD can determine $\chi (T)$ precisely. We reassess the uncertainty on the instanton contribution, arguing that it amounts to less than 20% in the effective action, or a factor of 20 in $\chi$ at $T=1.5\mathrm{GeV}$. We then combine the instanton uncertainty with a range of models for $\chi (T)$ at intermediate temperatures and determine the impact on the axion relic density. We find that for a given relic density and initial misalignment angle, the combined uncertainty amounts to a factor of 2–3 in the zero-temperature axion mass.

Toroidally compactified Yang-Mills theory on the lattice is studied by using the Hybrid Monte Carlo algorithm. When the compact dimensions are small, the theory naturally reduces to Yang-Mills with scalars. We confirm previous analytical and numerical results for pure gauge theory with scalars in ($0+1$) dimensions and at high temperatures to super-Yang-Mills in ($1+1$) dimensions. In ($1+1$) dimensions, our simulations confirm the previously conjectured phase diagram. Furthermore, we find evidence for the sequential breaking of the center symmetry in ($1+1$) dimensions as a function of the volume. In ($3+1$) dimensions we present first simulation results for the eigenvalue distribution of the Polyakov and Wilson loops, finding localized, nonuniform, and center-symmetric configurations as a function of the lattice coupling.

We study spatial isovector meson correlators in $N_f=2$ QCD with dynamical domain-wall fermions on $32^3\times 8$ lattices at temperatures $T=220–380\mathrm{MeV}$. We measure the correlators of spin-one ($J=1$) operators including vector, axial-vector, tensor and axial-tensor. Restoration of chiral $U(1{)}_A$ and $SU(2{)}_L\times SU(2{)}_R$ symmetries of QCD implies degeneracies in vector–axial-vector ($SU(2{)}_L\times SU(2{)}_R$) and tensor–axial-tensor ($U(1{)}_A$) pairs, which are indeed observed at temperatures above $T_c$. Moreover, we observe an approximate degeneracy of all $J=1$ correlators with increasing temperature. This approximate degeneracy suggests emergent $SU(2{)}_{CS}$ and $SU(4)$ symmetries at high temperatures, that mix left- and right-handed quarks.

Searches for double beta decay of ${}^{134}\mathrm{Xe}$ were performed with EXO-200, a single-phase liquid xenon detector designed to search for neutrinoless double beta decay of ${}^{136}\mathrm{Xe}$. Using an exposure of $29.6\mathrm{kg}·\mathrm{yr}$, the lower limits of ${\mathrm{T}}_{1/2}^{2\nu \beta \beta }>8.7\times {10}^{20}\mathrm{yr}$ and ${\mathrm{T}}_{1/2}^{0\nu \beta \beta }>1.1\times {10}^{23}\mathrm{yr}$ at 90% confidence level were derived, with corresponding half-life sensitivities of $1.2\times {10}^{21}\mathrm{yr}$ and $1.9\times {10}^{23}\mathrm{yr}$. These limits exceed those in the literature for ${}^{134}\mathrm{Xe}$, improving by factors of nearly $10^5$ and 2 for the two antineutrino and neutrinoless modes, respectively.

The gravitino mass is expected not to be much smaller than the Planck scale for a large fraction of vacua in flux compactifications. There is no continuous parameter to tune even by hand, and it seems that the gravitino mass can be small only as a result of accidental cancellation among period integrals weighted by integer-valued flux quanta. DeWolfe et al. [J. High Energy Phys. 02 (2005) 037] proposed paying close attention to vacua where the Hodge decomposition is possible within a number field, so that the precise cancellation takes place as a result of algebra. We focus on a subclass of those vacua—those with complex multiplication—and explore more on the idea in this article. It turns out, in Type IIB compactifications, that those vacua admit nontrivial supersymmetric flux configurations if and only if the reflex field of the Weil intermediate Jacobian is isomorphic to the quadratic imaginary field generated by the axidilaton vacuum expectation value. We also found that flux statistics are highly enriched on such vacua, as F-term conditions become linearly dependent.

The exterior electromagnetic fields of slowly rotating relativistic magnetized star in the braneworld are studied in detail. We have also obtained exact analytical solutions of the Maxwell equations for the magnetic and the electric fields inside the slowly rotating relativistic magnetized star in the braneworld. The dependence of the electromagnetic energy losses of the rotating magnetized star from the brane tension is also calculated and has been combined with the astrophysical data on pulsar period slowdown in order to get constraints on the brane parameter. We have found the upper limit for the brane parameter as $|Q^{*}|\lesssim 3\times {10}^{11}{\mathrm{cm}}^2$.

Observations of the cosmic microwave background (CMB) together with weak lensing measurements of the clustering of large scale cosmological structures and local measurements of the Hubble constant pose a challenge to the standard $\mathrm{\Lambda }\mathrm{CDM}$ cosmological model. On one side CMB observations imply a Hubble constant that is lower than local measurements and an amplitude of the lensing signal that is higher than direct measurements from weak lensing surveys. We investigate a way of relieving these tensions by adding dark radiation tightly coupled to an acoustic part of the dark matter sector and compare it to massive neutrino solutions. While these models offer a way of separately relieving the Hubble and weak lensing tensions they are prevented from fully accommodating both at the same time since the CMB requires additional cold dark matter when adding acoustic dark matter or massive neutrinos to preserve the same sharpness of the acoustic peaks which counteracts the desired growth suppression.

Einstein’s general theory of relativity is plagued by cosmological and black-hole type singularities Recently, it has been shown that infinite derivative, ghost free, gravity can yield nonsingular cosmological and mini-black hole solutions. In particular, the theory possesses a mass-gap determined by the scale of new physics. This paper provides a plausible argument, not a no-go theorem, based on the Area-law of gravitational entropy that within infinite derivative, ghost free, gravity nonsingular compact objects in the static limit need not have horizons.

Using a thin shell, the first law of thermodynamics, and a unified approach, we study the thermodymanics and find the entropy of a ($2+1$)-dimensional extremal rotating Bañados-Teitelbom-Zanelli (BTZ) black hole. The shell in ($2+1$) dimensions, i.e., a ring, is taken to be circularly symmetric and rotating, with the inner region being a ground state of the anti-de Sitter spacetime and the outer region being the rotating BTZ spacetime. The extremal BTZ rotating black hole can be obtained in three different ways depending on the way the shell approaches its own gravitational or horizon radius. These ways are explicitly worked out. The resulting three cases give that the BTZ black hole entropy is either the Bekenstein-Hawking entropy, $S=\frac{A_{+}}{4G}$, or an arbitrary function of $A_{+}$, $S=S(A_{+})$, where $A_{+}=2\pi r_{+}$ is the area, i.e., the perimeter, of the event horizon in ($2+1$) dimensions. We speculate that the entropy of an extremal black hole should obey $0\le S(A_{+})\le \frac{A_{+}}{4G}$. We also show that the contributions from the various thermodynamic quantities, namely, the mass, the circular velocity, and the temperature, for the entropy in all three cases are distinct. This study complements the previous studies in thin shell thermodynamics and entropy for BTZ black holes. It also corroborates the results found for a ($3+1$)-dimensional extremal electrically charged Reissner-Nordström black hole.

The interaction between two initially causally disconnected regions of the Universe is studied using analogies of noncommutative quantum mechanics and the deformation of Poisson manifolds. These causally disconnect regions are governed by two independent Friedmann-Lemaître-Robertson-Walker (FLRW) metrics with scale factors $a$ and $b$ and cosmological constants ${\mathrm{\Lambda }}_a$ and ${\mathrm{\Lambda }}_b$, respectively. The causality is turned on by positing a nontrivial Poisson bracket $[{\mathcal{P}}_{\alpha },{\mathcal{P}}_{\beta }]={\epsilon }_{\alpha \beta }\frac{\kappa }{G}$, where $G$ is Newton’s gravitational constant and $\kappa$ is a dimensionless parameter. The posited deformed Poisson bracket has an interpretation in terms of 3-cocycles, anomalies, and Poissonian manifolds. The modified FLRW equations acquire an energy-momentum tensor from which we explicitly obtain the equation of state parameter. The modified FLRW equations are solved numerically and the solutions are inflationary or oscillating depending on the values of $\kappa$. In this model, the accelerating and decelerating regime may be periodic. The analysis of the equation of state clearly shows the presence of dark energy. By completeness, the perturbative solution for $\kappa \ll 1$ is also studied.

The Minkowski vacuum state is expressed as an entangled state between the left and right Rindler wedges when it is constructed on the Rindler vacuum. In this paper, we further examine the entanglement structure and extend the expression to the future (expanding) and past (shrinking) Kasner spacetimes. This clarifies the origin of the quantum radiation produced by an Unruh-DeWitt detector in uniformly accelerated motion in the four-dimensional Minkowski spacetime. We also investigate the two-dimensional massless case where the quantum radiation vanishes but the same entanglement structure exists.