We report a lattice QCD calculation of the parton distribution function (PDF) of a deuteronlike dibaryon system using large-momentum effective theory. The calculation is done on three Wilson-clover ensembles with a fixed lattice spacing $a=0.105\mathrm{fm}$ and two pion masses. The lattice matrix elements are computed at proton momenta up to 2.46 GeV, with the signal of high-momentum modes being improved by applying the momentum smearing technique. The state-of-the-art renormalization, matching, and extrapolation are then applied to obtain the final result of the light-cone PDF. A comparison between the result of the dibaryon system and the sum of the proton and neutron PDFs is also given.

In high-energy particle physics, extracting parton distribution functions (PDFs) from lattice quantum chromodynamics (QCD) calculations remains a significant challenge, particularly due to the divergent nature of perturbative expansions at high orders. The presence of renormalon singularities in the Borel plane further hinders the accurate determination of PDFs, especially in the context of lattice QCD and effective field theory approaches like large momentum effective theory. This study explores the application of conformal mapping as a technique to improve the convergence of perturbative series for matching kernels. By transforming the Borel plane to map singularities onto the unit disk, this method mitigates the effects of divergent behavior in high-order perturbative expansions of matching kernels. The numerical analysis focuses on the matching kernel for quark correlation functions, using the CT18NNLO PDFs for u quarks and d quarks, along with next-to-next-to-next-to-leading-order hard kernel inputs. The results demonstrate that conformal mapping enhances the stability of the perturbative series, reducing the root-mean-square error by up to 40% compared to conventional $a_s$ series. These findings highlight the potential of conformal mapping to enhance the precision of PDFs and reduce theoretical uncertainties in high-order QCD calculations.

We perform a functional renormalization group analysis of a four-fermion model with $CP$ and $P$ violation to explore the nonperturbative infrared dynamics of quantum chromodynamics (QCD) within the Wilsonian renormalization group framework, particularly in the context of spontaneous $CP$-violation models. Our analysis of the fixed-point structure reveals that, in the large-$N_c$ limit, the $CP$-violating $\overline{\theta }$ parameter is dynamically induced and approaches $\pi ·(N_f/2)$ (where $N_f$ is the number of flavors) as the system enters the chirally broken phase. This behavior arises due to criticality and the large anomalous dimensions of the $U(1{)}_A$-violating four-fermion couplings. Furthermore, this trend appears to persist beyond the leading large-$N_c$ approximation, provided that the infrared dynamics of QCD remains dominated by the scalar condensate of the quark bilinear, as expected. Notably, our findings highlight that $CP$-violating four-fermion interactions, which are perturbatively irrelevant, can become relevant in the chirally broken phase through nonperturbative effects, with potential implications for spontaneous $CP$-violation scenarios.

More than twenty years have elapsed since the discovery of ${\chi }_{c1}(3872)$ [previously denoted as $X(3872)$], and an impressive amount of theoretical and experimental studies has been devoted to its properties, decays and production mechanisms. Despite the extensive work, a full understanding of the nature of ${\chi }_{c1}(3872)$ is still missing. In the present study we reconsider a theoretical framework based on the heavy quark large mass limit to analyze the radiative decays of heavy quarkonia, in particular the electric dipole transitions of ${\chi }_{c1}(2P)$ to $S$-wave charmonia. The results favorably compare to recent measurements for ${\chi }_{c1}(3872)$, obtained by the LHCb Collaboration, if this meson is identified with ${\chi }_{c1}(2P)$.

The color-flavor locked phase of high density QCD admits non-Abelian vortices that are superfluid vortices with confined color-magnetic fluxes. Vortex solutions were thus far constructed in an axially symmetric Ansatz with common vortex winding in the left- and right-handed diquark condensates. In this paper, we explore vortex solutions without any Ansatz. In addition to axially symmetric configurations known before, we find that the axial symmetry is broken in certain parameter regions; in one case a single vortex is split into two chiral non-Abelian vortices, i.e., vortices with winding only in the left- or right-handed diquark condensate, and they are connected by one or two domain walls forming a non-Abelian vortex molecule. In the other case, a chiral non-Abelian vortex molecule is confined inside a domain wall elongated to spatial infinity.

Using a sample of $(10087\pm 44)\times {10}^{6}J/\psi$ events accumulated with the BESIII detector, we analyze the decays $\eta \to {\pi }^{+}{\pi }^{-}{l}^{+}{l}^{-}$ ($l=e$ or $\mu$) via the process $J/\psi \to \gamma \eta$. The branching fraction of $\eta \to {\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-}$ is measured to be $\mathcal{B}(\eta \to {\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-})=(3.07\pm 0.12_{\mathrm{stat}}\pm 0.19_{\mathrm{syst}})\times {10}^{-4}$. No signal events are observed for the $\eta \to {\pi }^{+}{\pi }^{-}{\mu }^{+}{\mu }^{-}$ decay, leading to an upper limit on the branching fraction of $\mathcal{B}(\eta \to {\pi }^{+}{\pi }^{-}{\mu }^{+}{\mu }^{-})<4.0\times {10}^{-7}$ at the 90% confidence level. Furthermore, the $CP$-violation asymmetry parameter is found to be ${\mathcal{A}}_{CP}(\eta \to {\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-})=(-4.04\pm 4.69_{\mathrm{stat}}\pm 0.14_{\mathrm{syst}})\%$, showing no evidence of $CP$-violation with current statistics. Additionally, we extract the transition form factor from the decay amplitude of $\eta \to {\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-}$. Finally, axionlike particles are searched for via the decay $\eta \to {\pi }^{+}{\pi }^{-}a,a\to e^{+}{e}^{-}$, and upper limits on this branching fraction relative to that of $\eta \to {\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-}$ are presented as a function of the axionlike particle mass in the range $5–200\mathrm{MeV}/c^2$.

Spherical proportional counters (SPCs) are gaseous particle detectors sensitive to single ionization electrons in their target media, with large detector volumes and low background rates. The $\text{NEWS-G}$ collaboration employs this technology to search for low-mass dark matter, having previously performed searches with detectors at the Laboratoire Souterrain de Modane (LSM), including a recent campaign with a 135 cm diameter SPC filled with methane. While in situ calibrations of the detector response were carried out at the LSM, measurements of the mean ionization yield and fluctuations of methane gas in SPCs were performed using a 30 cm diameter detector. The results of multiple measurements taken at different operating voltages are presented. A UV laser system was used to measure the mean gas gain of the SPC, along with ${}^{37}\mathrm{Ar}$ and aluminum-fluorescence calibration sources. These measurements will inform the energy response model of future operating detectors.

We introduce a generative AI model to obtain type IIB brane configurations that realize toric phases of a family of $4D$ $\mathcal{N}=1$ supersymmetric gauge theories. These $4D$ $\mathcal{N}=1$ quiver gauge theories are world volume theories of a D3-brane probing a toric Calabi-Yau 3-fold. The type IIB brane configurations are given by the coamoeba projection of the mirror curve associated with the toric Calabi-Yau 3-fold. The shape of the mirror curve and its coamoeba projection, as well as the corresponding type IIB brane configuration and the toric phase of the $4d$ $\mathcal{N}=1$ theory, all depend on the complex structure moduli parametrizing the mirror curve. We train a generative AI model, a conditional variational autoencoder (CVAE), that takes a choice of complex structure moduli as input and generates the corresponding coamoeba. This enables us not only to obtain a high-resolution representation of the entire phase space for a family of $4D$ $\mathcal{N}=1$ theories corresponding to the same toric Calabi-Yau 3-fold, but also to continuously track the movements of the mirror curve and the branes wrapping the curve in the corresponding type IIB brane configurations during phase transitions associated with Seiberg duality.

In this work, we have considered a spherically symmetric nonrotating charged black hole geometry where Newton’s gravitational constant and the charge of the black hole flow with the energy scale. We have used the Kretschmann scale identification to write down the finite cutoff for the momentum scale regarding the proper distance. Introducing the flow of running couplings, the event horizon radius of the black hole using the quantum-improved Reissner-Nordstrom metric was found by Ishibashi et al. [Phys. Rev. D 104, 066016 (2021)]. We have, in this work, explored the thought experiment of a two-level atom freely falling into the event horizon of a quantum-improved charged black hole and have computed the transition probability of the atom for going from its ground state to the excited state via emission of a virtual photon. We find that the probability deviates slightly from the pure Planckian spectrum. We have shown that this deviation is due to the presence of an incomplete lower gamma function in the distribution function. We have then computed the horizon brightened acceleration radiation entropy and found that it is identical to the Bekenstein-Hawking entropy followed by the renormalization group correction terms including an inverse logarithmic and a square root of the area term due to emitting photons.

Understanding the loop corrections to cosmological observables is of paramount importance for having control on the quantum consistency of a theory in an expanding universe as well as for phenomenological reasons. In the present work, we begin with a systematic study of such corrections in the context scalar toy models whose perturbative Bunch-Davies wave function enjoys an intrinsic definition in terms of cosmological polytopes, focusing on one-loop graphs. Owing to the underlying twisted period integral representation they admit, their combinatorial structure along with their vector space structure, emerging from polynomial ideals algebra and intersection theory, are exploited to set-up and analyze the differential equations that the two- and three-site one-loop corrections have to satisfy upon variation of the external kinematic variables. We find that, while the two-site contribution can be written in terms of multiple polylogarithms, this is no longer true for the three-site case, for which elliptic structures appear. As a nontrivial check, we consider the scattering amplitude limit, recovering the known result in terms of polylogarithms only.

The detection of parity violation in the isotropic stochastic gravitational wave background (SGWB) will serve a crucial probe for new physics, particularly in parity-violating theories of gravity. The joint observations by the planned space-borne gravitational wave detectors, LISA and TAIJI, will offer a unique opportunity to observe such effects in the millihertz (mHz) band. This study evaluates the detectability of parity violation in the SGWB using two network configurations: LISA-TAIJIp and LISA-TAIJIm. The former configuration consists of LISA (inclined at $+60°$ relative to the ecliptic plane) and TAIJIp (also inclined at $+60°$), while the latter network pairs LISA with TAIJIm (inclined at $-60°$). Our analysis demonstrates that the sensitivity of the LISA-TAIJIm network to parity violation in the SGWB is approximately one order of magnitude greater than that of the LISA-TAIJIp network at lower frequencies. To quantify the performance of the two networks, we evaluate the signal-to-noise ratios for different spectral shapes, including power-law, single-peak, and broken power-law models, and estimate parameter determination using the Fisher information matrix. The results confirm that LISA-TAIJIm outperforms LISA-TAIJIp in detecting the SGWB with circular polarization components, offering a superior opportunity to test parity-violating gravitational constraints on various mechanisms in the mHz band.

In the present work, we obtain and analyze a new class of analytical solutions of magnetically charged black bounces in the $k$-essence theory, spherically symmetric in ($3+1$) dimensions, coupled to nonlinear electrodynamics (NED). We consider two metric models, Simpson-Visser and Bardeen-type black bounces, for the $k$-essence configurations $n=1/3$ and $n=1/5$. We obtain in an analytical way the scalar field, the field potential, and Lagrangian NED, which are necessary to support the metrics. We analyze the behavior of these quantities and the energy conditions due to the scalar field and the NED.

We investigate the cosmological observables using the Euclidean path integral approach. Specifically, we study both the no-boundary compact instantons scenario and the Euclidean wormholes scenario that can induce the creation of two universes from nothing. It is known that perturbations associated with the no-boundary scenario can only be consistent with the Bunch-Davies vacuum. Here we conjecture that the Euclidean wormholes can allow for a class of de Sitter invariant vacua, the so-called $\alpha$-vacua, where the Bunch-Davies vacuum is a special case. This therefore provides the $\alpha$-vacua a geometrical origin. As an aside, we discuss a subtle phase issue when considering the power spectrum related to $\alpha$-vacua in the closed universe framework.

We investigate the extent to which modifying the ionization history at cosmological recombination can relieve the Hubble tension, taking into account all relevant datasets and considering the implications for the galaxy clustering parameter $S_8$ and the matter density fraction ${\mathrm{\Omega }}_m$. We use the linear response approximation to systematically search for candidate ionization histories parameterized with a cubic-spline that provide good fits to the Planck CMB and DESI BAO data while relieving the $H_0$ tension, followed by MCMC fits of the most promising candidate models to the data. We also fit to the data a physically motivated phenomenological model of ionization history that has four parameters. Our main result is that models of modified recombination can reduce the Hubble tension to below $2\sigma$ while improving the fit to the current CMB and BAO data and reducing the $S_8$ tension. The promising candidate ionization histories have simple shapes, with no need for an oscillatory dependence on redshift. Our study also demonstrates the importance of the high-resolution CMB temperature and polarization anisotropies for constraining modified recombination, with the candidate models in this study showing varying levels of agreement with the current ACT DR4 and SPT-3G data.

Recent results from DESI combined with cosmic microwave background data give the tightest constraints on the sum of neutrino masses to date. However, these analyses approximate the neutrino mass hierarchy by three degenerate-mass (DM) neutrinos, instead of the normal (NH) and inverted hierarchies (IH) informed by terrestrial neutrino oscillation experiments. Given the stringency of the upper limits from DESI data, we test explicitly whether the inferred neutrino mass constraints are robust to the choice of neutrino mass ordering using both Bayesian and frequentist methods. For Planck data alone, we find that the DM hierarchy presents a good approximation to the physically motivated hierarchies while showing a strong dependence on the assumed lower bound of the prior, confirming previous studies. For the combined Planck and DESI baryon acoustic oscillation data, we find that assuming NH ($M_{\mathrm{tot}}<0.13\mathrm{eV}$) or IH ($M_{\mathrm{tot}}<0.16\mathrm{eV}$) loosens the Bayesian upper limits compared to the DM approximation ($M_{\mathrm{tot}}<0.086\mathrm{eV}$). The frequentist analysis shows that the different neutrino models fit the data equally well and the loosening of the constraints can thus be attributed to the lower bounds induced by NH and IH. Overall, we find that the DM hierarchy presents a good approximation to the physically motivated hierarchies also for Planck + DESI data as long as the corresponding lower neutrino mass bounds are imposed.

An oscillating scalar field can behave like cold dark matter in the expanding Universe. In relativistic cosmology, this perspective is primarily reasoned by an evolution of a background scalar field and its subhorizon perturbations in a matter-dominated era. A corresponding relativistic description is usually based on the ansatz that the perturbations oscillate in the same way as the background field and on time averaging to find the oscillation amplitudes. In contrast, the presented approach makes no initial assumptions about the perturbation behavior and does not use time averages. It is shown that, although the previous treatments are valid only well inside the Hubble scale, the scalar field reproduces the cold dark matter scenarios on the superhorizon scale and also throughout the evolution of the Universe from the beginning of the oscillations. The misunderstanding about the Jeans length scale in the matter-dominated epoch is also clarified. An analog of the Jeans effect is found in a radiation-dominated era. It can prevent an overproduction of small halos for the scalars with $m\sim {10}^{-13}\mathrm{eV}$.

Supersymmetry (SUSY) addresses several problems of the Standard Model, such as the naturalness problem and gauge coupling unification, and can provide cosmologically viable dark matter candidates. SUSY must be broken at high energy scales with mechanisms like gravity, anomaly, gauge mediation, etc. This paper revisits the gauge mediated SUSY breaking (GMSB) scenarios in the context of data from the Large Hadron Collider (LHC) experiment. The ATLAS monophoton search at 139 inverse femtobarn integrated luminosity at the 13 TeV LHC, in the context of a simplified general gauge mediation (GGM) scenario (which is a phenomenological version of GMSB with an agnostic approach to the nature of the hidden sector), relies on assumptions that do not hold across the entire parameter space. We identify a few crucial assumptions regarding the decay widths of SUSY particles into final states with gravitinos that affect the LHC limits on the masses of the SUSY particles. Our study aims to reinterpret the ATLAS constraints on the gluino-NLSP mass plane, considering all possible decay modes of SUSY particles in a realistic GGM model.

The shortcomings of the Standard Model (SM) motivate its extension to accommodate new expected phenomena, such as dark matter and neutrino masses. However, such extensions are generally more complex due to the presence of a large number of free parameters and additional phenomenology. Understanding how theoretical and experimental limits affect the parameter spaces of new models, individually and collectively, is of utmost importance for conducting model status analysis, motivating precise computations, or model building aimed at solving certain issues. However, checking the constraints usually requires a large amount of time using a chain of physics tools. We demonstrate, for the first time, the application of deep learning for the multilabel classification of a group of theoretical and experimental constraints in the dark doublet phase of the next-to two-Higgs-doublet model, as a representative nine-dimensional parameter space. We analyze the issue of class imbalance and the ability of the classifier to learn joint class distributions. We demonstrate the time advantage compared to physics tools, with the classifier achieving orders of magnitude faster checks on groups of constraints and strong performance. The classifier performed strongly in terms of identifying regions where all constraints are valid or invalid, as well as regions where one or more of the constraints are valid or invalid simultaneously. This approach can be applied to any extension beyond the SM with the potential to aid HEP tools or act as a surrogate for fast model status checks. To that end, we provide a python tool hepmlc for generating and investigating multilabel classifiers for SM extensions.

We propose a three-Higgs-doublet model (3HDM) that goes beyond natural flavor conservation and in which each of the three Higgs doublets couples mainly to a single generation of fermions via nonstandard Yukawa structures. A hierarchy in the vacuum expectation values of the three Higgs doublets can partially address the Standard Model flavor puzzle. In light of the experimentally observed 125 GeV Higgs boson, we primarily work within a 3HDM alignment limit such that a Standard Model-like Higgs is recovered. In order to reproduce the observed Cabibbo–Kobayashi–Maskawa mixing among quarks, the neutral Higgs bosons of the theory necessarily mediate flavor changing neutral currents at the tree level. We consider constraints from neutral kaon, $B$ meson, and $D$ meson mixing as well as from the rare leptonic decays $B_s/B^0/K_L\to {\mu }^{+}{\mu }^{-}/e^{+}{e}^{-}$. We identify regions of parameter space in which the new physics Higgs bosons can be as light as a TeV or even lighter.

Confining QCD-like theories close to the conformal window have a “walking” coupling. This is believed to lead to a light singlet scalar meson in the low-energy spectrum, a dilaton, which is the pseudo-Nambu-Goldstone boson for the approximate scale symmetry. Extending chiral perturbation theory to include the dilaton requires a new small parameter to control the dilaton mass and its interactions. In our previous work we derived a systematic power counting for the dilaton couplings by matching the effective low-energy theory to the underlying theory using mild assumptions. In this paper we examine two alternative power countings which were proposed in the literature based on a phenomenological picture for the conformal transition. We find that one of these power countings fails, in fact, to generate a systematic expansion; the other coincides with the power counting we derived. We also point out that the so-called $\mathrm{\Delta }$-potential coincides with the tree-level potential of the former, invalid, power counting.