In the present paper we discuss properties of a model of a ring wormhole, recently proposed by Gibbons and Volkov [Phys. Rev. D 96, 024053 (2017); J. Cosmol. Astropart. Phys. 05 (2017) 039; Phys. Lett. B 760, 324 (2016)]. Such a wormhole connects two flat spacetimes which are glued through disks of the radius $a$ bounded by the string with negative angle deficit $-2\pi$. The presence of the string’s matter violating the null-energy condition makes the wormhole static and traversable. We study gravitational field of static sources in such a spacetime in the weak-field approximation. In particular, we discuss how a field of an oblate thin massive shell surrounding one of the wormhole’s mouths is modified by its presence. We also obtain a solution of a similar problem when both mouths of the wormhole are located in the same space. This approximate solution is found for the case when the distance $L$ between these mouths is much larger than the radius $a$ of the ring. We demonstrate that the corresponding locally static gravitational field in such a multiply connected space is nonpotential. As a result of this, the proper time gap for the clock’s synchronization linearly grows with time and closed timelike curves are formed. This process inevitably transforms such a traversable ring wormhole into a time machine. We estimate the timescale of this process.

In recent years, significant progress has been made in the computation of conservative and dissipative scattering observables using the post-Minkowskian approach to gravitational dynamics. However, for accurate modeling of unbound orbits, an appropriate effective-one-body (EOB) resummation of the post-Minkowski results that also accounts for dissipative dynamics is desirable. As a step in this direction, we consider the electromagnetic analog of this problem here. We show that a six-parameter equation of motion encapsulates the effective-one-body dynamics for the electromagnetic scattering problem appropriate to third order in the coupling constant. Three of these six parameters describe the conservative part of the dynamics, while the rest correspond to the radiation-reaction effects. Here we show that only two radiation-reaction-related parameters are important at the desired order, making the effective number of parameters in our formalism to be 5. We compute the explicit forms of these five parameters by matching EOB scattering observables to that of the original two-body ones computed by Saketh et al. [Phys. Rev. Res. 4, 013127 (2022)]. Interestingly, our formalism leads to a conjecture for the subleading angular momentum loss, for which no precise computations exist. In addition, we demonstrate that the bound-orbit observables computed using our method are in perfect agreement with those calculated using unbound-to-bound analytical continuation techniques. Finally, we qualitatively discuss the extension of our formalism to gravity.

We give a simple prescription for relating different solutions to the zero-rest-mass field equations in conformally flat space-time via complex conformal transformations and changes in reality conditions. We give several examples including linearized black holes. In particular, we show that the linearized Plebański-Demiański and Schwarzschild fields are related by a complex translation and a complex special conformal transformation. Similar results hold for the linearized Kerr and C-metric fields and for a peculiar toroidal singularity.

We compute the leading and subleading spin effects through the second post-Newtonian order (2PN) in spherical harmonic modes of gravitational waveforms from inspiralling compact binaries in noncircular orbits with nonprecessing components. The two spin couplings, linear-in-spin (spin-orbit) and quadratic-in-spin (spin-spin) that appear in 2PN waveforms are computed with desired accuracy, and explicit expressions for relevant modes are derived. The modes that have spin corrections through 2PN include $(\ell ,|m|)=((2,2),(2,1),(3,3),(3,2),(3,1),(4,3),(4,1))$ modes. Additionally, two $m=0$ modes—(2,0) and (3,0)—also contribute to the 2PN order. Closed-form expressions for these modes for compact binaries in general orbits as well as in elliptical orbits are provided. While the general orbit results can be used to study signals from binaries in orbits of arbitrary shape and nature, elliptical orbit results are applicable to systems with arbitrary eccentricities. We also express the elliptical orbit results as leading eccentric corrections to the circular results. Our prescription represents, the first, fully analytical treatment that combines spins, eccentricity, and higher modes together and completes computation of spin effects through 2PN order. These should find immediate applications in inspiral-merger-ringdown modeling for eccentric mergers including the effect of nonprecessing spins and higher modes as well as in parameter estimation analyses employing an inspiral waveform.

We are in the era of precision cosmology which offers us a unique opportunity to investigate beyond standard model physics. Toward this endeavor, inflaton is assumed to be a perfect new physics candidate. In this submission, we explore the phenomenological impact of the latest observation of PLANCK and $\mathrm{BICEP}/Keck$ data on the physics of inflation. We particularly study three different models of inflation, namely $\alpha$-attractor E, T, and the minimal plateau model. We further consider two different post-inflationary reheating dynamics driven by inflaton decaying into bosons and fermions. Given the latest data in the inflationary $(n_s-r)$ plane, we derive detailed phenomenological constraints on different inflaton parameters and the associated physical quantities, such as inflationary $e$-folding number, $N_k$, reheating temperatures $T_{\mathrm{re}}$. Apart from considering direct observational data, we further incorporate the bounds from primordial gravitational waves (PGWs) and different theoretical constraints. Rather than in the laboratory, our results illustrate the potential of present and future cosmological observations to look for new physics in the sky.

We propose that primordial black hole (PBH) binary systems can lead to standard timers in tracking the evolution of the Universe. Through gravitational waves from monochromatic PBH binaries, the probability distribution on major axis and eccentricity from the same redshift is obtained. By studying the dynamical evolution of PBH binaries from the initial probability distribution to observed redshifted ones, the redshift-time calibration can be extracted, which can constrain cosmological models. A general formalism of the standard timer is further concluded based on the evolution of statistical distribution in dynamical systems.

We present a further observational analysis of the ${\mathrm{\Lambda }}_{\mathrm{s}}\mathrm{CDM}$ model proposed in Akarsu et al. [Phys. Rev. D 104, 123512 (2021)]. This model is based on the recent conjecture suggesting the Universe has transitioned from anti–de Sitter vacua to de Sitter vacua (viz., the cosmological constant switches sign from negative to positive), at redshift $z_{†}\sim 2$, inspired by the graduated dark energy model proposed in Akarsu et al. [Phys. Rev. D 101, 063528 (2020)]. ${\mathrm{\Lambda }}_{\mathrm{s}}\mathrm{CDM}$ was previously claimed to simultaneously relax five cosmological discrepancies, namely, the $H_0$, $S_8$, and $M_B$ tensions along with the $\mathrm{Ly}\text{−}\alpha$ and ${\omega }_{\mathrm{b}}$ anomalies, which prevail within the standard $\mathrm{\Lambda }\mathrm{CDM}$ model as well as its canonical/simple extensions. In the present work, we extend the previous analysis by constraining the model using the Pantheon data (with and without the SH0ES $M_B$ prior) and/or the completed BAO data along with the full Planck CMB data. We find that ${\mathrm{\Lambda }}_{\mathrm{s}}\mathrm{CDM}$ exhibits a better fit to the data compared to $\mathrm{\Lambda }\mathrm{CDM}$, and simultaneously relaxes the six discrepancies of $\mathrm{\Lambda }\mathrm{CDM}$, viz., the $H_0$, $M_B$, $S_8$, $\mathrm{Ly}\text{−}\alpha$, $t_0$, and ${\omega }_{\mathrm{b}}$ discrepancies, all of which are discussed in detail. When the $M_B$ prior is included in the analyses, ${\mathrm{\Lambda }}_{\mathrm{s}}\mathrm{CDM}$ performs significantly better in relaxing the $H_0$, $M_B$, and $S_8$ tensions with the constraint $z_{†}\sim 1.8$ even when the $\mathrm{Ly}\text{−}\alpha$ data (which imposed the $z_{†}\sim 2$ constraint in the previous studies) are excluded. In contrast, the presence of the $M_B$ prior causes only negligible improvements for $\mathrm{\Lambda }\mathrm{CDM}$. Thus, the ${\mathrm{\Lambda }}_{\mathrm{s}}\mathrm{CDM}$ model provides remedy to various cosmological tensions simultaneously, only that the galaxy BAO data hinder its success to some extent.

Future gamma-ray experiments, such as the e-ASTROGAM and AMEGO telescopes, can detect the Hawking radiation of photons from primordial black holes (PBHs) if they make up a fraction or all of dark matter. PBHs can analogously also Hawking radiate new particles, which is especially interesting if these particles are mostly secluded from the Standard Model sector, since they might therefore be less accessible otherwise. A well-motivated example of this type is axionlike particles (ALPs) with a tiny coupling to photons. We assume that the ALPs produced by PBHs decay into photons well before reaching the Earth, so these will augment the photons directly radiated by the PBHs. Remarkably, we find that the peaks in the energy distributions of ALPs produced from PBHs are different than the corresponding ones for Hawking radiated photons due to the spin-dependent graybody factor. Therefore, we demonstrate that this process will in fact distinctively modify the PBHs’ gamma-ray spectrum relative to the Standard Model prediction. We use monochromatic asteroid-mass PBHs as an example to show that e-ASTROGAM can observe the PBH-produced ALP gamma-ray signal (for masses up to $\sim 60\mathrm{MeV}$) and further distinguish it from Hawking radiation without ALPs. By measuring the gamma-ray signals, e-ASTROGAM can thereby probe yet unexplored parameters in the ALP mass and photon coupling.

Neutrino oscillations are genuine quantum phenomena in which coherent oscillations are maintained over a long distance. As a result, in principle, the phenomena can be studied efficiently using quantum simulations. In today’s noisy quantum hardware, encoding neutrinos in a multiqubit system requires a redundant basis and tricky entangling gates. We encode a three-flavor neutrino in a superconducting qutrit and study its oscillations using Pontecorvo-Maki-Nakagawa-Sakata theory with time evolution expressed in terms of single qutrit gates. The qutrit is engineered from the multilevel structure of IBM transmon devices. High-fidelity gate control and readout are fine-tuned using programming microwave pulses using a high-level language. Our quantum simulations on real hardware match the analytical calculations well in three oscillation cases: vacuum, interaction with matter, and $CP$ violation.

Black holes can be produced in collapse of small-scale dark matter structures, which can happen at any time from the early to present-day Universe. Microstructure black holes (MSBHs) can have a wide range of masses. Small MSBHs evaporate via Hawking radiation with lifetimes shorter than the age of the Universe, but they are not subject to the usual early-Universe bounds on the abundance of small primordial black holes. We investigate the possible signal of such a population of exploding, late-forming black holes, constraining their abundance with observations from diffuse extragalactic gamma- and x-ray sources, the Galactic Center, and dwarf spheroidal galaxies.

We consider different types of storage rings as precision probes of axion-mediated monopole-dipole forces. We show that current and planned experiments aiming to measure magnetic and electric dipole moments of protons, muons. and electrons very precisely may explore new parts of the parameter space beyond existing laboratory bounds and, in some cases, beyond astrophysical constraints. Remarkably, a light axion coupled to muons may explain the FNAL/BNL $(g-2{)}_{\mu }$ anomaly as an environmental effect—the coherent axion field generated by the earth nucleons induces an extra contribution to the anomalous precession frequency of the muon explaining the discrepancy with respect to the SM prediction.

Topology and generalized symmetries in the $SU(N)/{\mathbb{Z}}_N$ gauge theory are considered in the continuum and the lattice. Starting from the $SU(N)$ gauge theory with the ’t Hooft twisted boundary condition, we give a simpler explanation of the van Baal’s proof on the fractionality of the topological charge. This description is applicable to both continuum and lattice by using the generalized Lüscher’s construction of topology on the lattice. Thus we can recover the $SU(N)/{\mathbb{Z}}_N$ principal bundle from lattice $SU(N)$ gauge fields being subject to the ${\mathbb{Z}}_N$-relaxed cocycle condition. We explicitly demonstrate the fractional topological charge, and verify an equivalence with other constructions reported recently based on different ideas. Gauging the ${\mathbb{Z}}_N$ 1-form center symmetry enables lattice gauge theories to couple with the ${\mathbb{Z}}_N$ 2-form gauge field as a simple lattice integer field, and to reproduce the Kapustin-Seiberg prescription in the continuum limit. Our construction is also applied to analyzing the higher-group structure in the $SU(N)$ gauge theory with the instanton-sum modification.

Searching for exotic multiquark states and elucidating their nature remains a central topic in understanding quantum chromodynamics–the underlying theory of the strong interaction. Two of the most studied such states are the charm-strange states $D_{s0}^{*}(2317)$ and $D_{s1}(2460)$. In this paper, we show for the first time that their prompt production yields in inclusive $e^{+}{e}^{-}\to c\overline{c}$ collisions near $\sqrt{s}=10.6\mathrm{GeV}$ measured by the BABAR collaboration, $Y(D_{s0}^{*}(2317))$ and $Y(D_{s1}(2460))$, in particular the ratio $R=Y(D_{s0}^{*}(2317))/Y(D_{s1}(2460))$, can be well explained in the molecular picture, which provide a highly nontrivial verification of their nature being $DK/D^{*}K$ molecules. On the contrary, treating them as pure $c\overline{s}$ $P$-wave states, the statistical model predicts a ratio $R$ smaller than unity, in contrast with the experimental central value, though in agreement with it considering its relatively large uncertainty. In addition, we predict the production yield of the $D\overline{D}K$ three-body bound state, $K_{c\overline{c}}(4180)$, in $e^{+}{e}^{-}\to c\overline{c}$ collisions and find that it is within the reach of the ongoing Belle II experiment. The present study demonstrates the feasibility of a novel method to unravel the nature of exotic hadrons and the potential of electron-positron collisions in this regard.

We calculate the entanglement entropy of a model proton wave function in coordinate space by integrating out degrees of freedom outside a small circular region $\overline{A}$ of radius $L$, where $L$ is much smaller than the size of the proton. The wave function provides a nonperturbative distribution of three valence quarks. In addition, we include the perturbative emission of a single gluon and calculate the entanglement entropy of gluons in $\overline{A}$. For both quarks and gluons, we obtain the same simple result: $S_E=-\int \frac{dx}{\mathrm{\Delta }x}{N}_{L^2}(x)\log [N_{a^2}(x)]$, where $a$ is the UV cutoff in coordinate space and $\mathrm{\Delta }x$ is the longitudinal resolution scale. Here $N_S(x)$ is the number of partons (of the appropriate species) with longitudinal momentum fraction $x$ inside an area $S$. It is related to the standard parton distribution function by $N_S(x)=\frac{S}{A_p}\mathrm{\Delta }xF(x)$, where $A_p$ denotes the transverse area of the proton.

The diabatic framework generalizes the adiabatic approximation built into the Born-Oppenheimer (BO) formalism and is devised to rigorously incorporate the mixing of BO-approximation eigenstates with two-particle thresholds. We recently applied this framework in a bound-state approximation to the mixing of hidden-charm dynamical-diquark tetraquark states with open-charm dimeson thresholds. Since almost all of these states are observed as above-threshold resonances, we here implement the corresponding scattering formalism to allow for a study of exotic tetraquark resonances within the diabatic framework. We calculate elastic open-charm dimeson cross sections (in channels with zero, open, and hidden strangeness) as functions of center-of-mass energy and observe the development of true resonances, near resonances, and various threshold cusp effects. As an example, ${\chi }_{c1}(3872)$ can originate in the $1^{++}$ channel as a diquark-antidiquark state enhanced by the $D^0{\overline{D}}^{*0}$ threshold, with or without an additional contribution from the conventional charmonium ${\chi }_{c1}(2P)$ state.

We present the resummed predictions consisting of both soft-virtual (SV) as well as next-to-SV (NSV) threshold logarithms to all orders in perturbative QCD for the rapidity distribution of Higgs boson up to next-to-next-to-leading order plus next-to-next-to-leading-logarithmic $(\mathrm{NNLO}+\overline{\mathrm{NNLL}})$ accuracy at LHC. Using our recent formalism, the resummation is carried out in the double Mellin space by restricting the NSV contributions only from diagonal $gg$ channel. We perform the inverse Mellin transformation using the minimal prescription procedure and match it with the corresponding fixed-order results. We do a detailed analysis of the numerical impact of the resummed result. The K-factor values at different logarithmic accuracy suggest that the prediction for the rapidity distribution converges and becomes more reliable at $\mathrm{NNLO}+\overline{\mathrm{NNLL}}$ order. Further, we observe that the inclusion of resummed NSV contribution improves the renormalization scale uncertainty at every order in perturbation theory. However, the uncertainty due to factorization scale increases by the addition of resummed $\mathrm{SV}+\mathrm{NSV}$ predictions to the fixed-order rapidity distribution.

A search for the rare hadronic decay $B_s^0\to p\overline{p}$ is performed using proton-proton collision data recorded by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of $6{\mathrm{fb}}^{-1}$. No evidence of the decay is found and an upper limit on its branching fraction is set at $\mathcal{B}(B_s^0\to p\overline{p})<4.4(5.1)\times {10}^{-9}$ at 90% (95%) confidence level; this is currently the world’s best upper limit. The decay mode $B^0\to p\overline{p}$ is measured with very large significance, confirming the first observation by the LHCb experiment in 2017. The branching fraction is determined to be $\mathcal{B}(B^0\to p\overline{p})=(1.27\pm 0.15\pm 0.05\pm 0.04)\times {10}^{-8}$, where the first uncertainty is statistical, the second is systematic and the third is due to the external branching fraction of the normalization channel $B^0\to K^{+}{\pi }^{-}$. The combination of the two LHCb measurements of the $B^0\to p\overline{p}$ branching fraction yields $\mathcal{B}(B^0\to p\overline{p})=(1.27\pm 0.13\pm 0.05\pm 0.03)\times {10}^{-8}$.

This paper presents a search for the rare flavor-changing neutral current process $B^0\to K^{*0}{\tau }^{+}{\tau }^{-}$ using data taken with the Belle detector at the KEKB asymmetric energy $e^{+}{e}^{-}$ collider. The analysis is based on the entire $\mathrm{\Upsilon }(4S)$ resonance data sample of $711{\mathrm{fb}}^{-1}$, corresponding to $772\times {10}^{6}B\overline{B}$ pairs. In our search we fully reconstruct the companion $B$ meson produced in the process $e^{+}{e}^{-}\to \mathrm{\Upsilon }(4S)\to B\overline{B}$ from its hadronic decay modes, and look for the decay $B^0\to K^{*0}{\tau }^{+}{\tau }^{-}$ in the rest of the event. No evidence for a signal is found. We report an upper limit on the branching fraction $\mathcal{B}(B^0\to K^{*0}{\tau }^{+}{\tau }^{-})<3.1\times {10}^{-3}$ at 90% confidence level. This is the first direct limit on $\mathcal{B}(B^0\to K^{*0}{\tau }^{+}{\tau }^{-})$.