Phase transitions in the early Universe give rise to effective masses for massless fields in the symmetry-broken phase. We perform lattice simulations to study the dynamical impact of a mass-acquiring spectator field on the evolution of first-order phase transitions and the associated gravitational-wave production, while keeping the effective potential responsible for bubble nucleation fixed. In addition to the well-known friction effects, we identify a novel effect that significantly enhances the strength of first-order phase transitions. In contrast to the general scenario, although the effective potential governs the tunneling rate, the amplitude of the $\chi$ field is strongly suppressed inside the true vacuum bubble, resulting in a faster bubble expansion than predicted by the effective potential alone. The amplitude of the mass-acquiring field is highly suppressed in the true vacuum bubbles, resulting in additional release of vacuum energy that concentrate on the bubble walls. We further develop an analytical framework that not only explains our numerical results but can also be used to improve the estimation of gravitational-wave signals in related phase-transition scenarios.

In this work, we constrain the value of ${\sigma }_8$ for the normal and self-accelerating branch of a Dvali-Gabadadze-Porrati brane embedded in a five-dimensional Minkowski space-time. For that purpose, we first constrain the background model parameters $H_0$, ${\mathrm{\Omega }}_{m0}$, ${\mathrm{\Omega }}_{r0}$, and $M$ using the $\mathrm{Pantheon}+\text{catalog}$ and a mock catalog of gravitational waves. Then, we numerically solve the equation for dark matter scalar perturbations using the dynamic scaling solution for the master equation. Finally, we found that the evolution of matter density perturbations in both branches is different from the $\mathrm{\Lambda }\mathrm{CDM}$ model and that the value of ${\sigma }_8=0.774\pm 0.027$ for the normal branch and ${\sigma }_8=0.913\pm 0.032$ for the self-accelerating branch.

Primordial power spectra with low power at long wavelengths can alleviate lensing anomaly. However the extent to which data favors such a primordial spectrum is not clear. In this work, we investigate power suppression and related mitigation of lensing anomaly with the help of phenomenological models that are valid over scales of interest. We consider simple extensions to nearly scale invariant power spectra such as those that include running and running of running of the spectral index. We perform Bayesian analysis of these models, which are agnostic about power suppression, with Planck legacy data and show that data tend to choose parameters that lead to power suppression at low multipoles. We then investigate the connection between power suppression and alleviation of lensing anomaly and show that lensing anomaly is mitigated the most in models with maximum suppression of power at low multipoles. We also analyze the significance of these findings using information criteria. These results are further analyzed in the light of Planck Release 4 data using CamSpec, High-$\ell$ Likelihood on Polarized Power spectra (HiLLiPoP), and Low-$\ell$ Likelihood on Polarized Power spectra (LoLLiPoP) likelihoods in which departure of lensing parameter from one is significantly reduced. Furthermore, we investigate the ability of near-ultimate future CMB missions such as ECHO to put tighter constraints on these models and to settle the issue. We conclude that we can make stronger conclusions about the presence of power suppression in the future by studying such simple phenomenological models.

Magnetic monopoles are a long-standing prediction of Grand Unified Theories, yet their efficient production in early universe phase transitions would lead to a monopole abundance that far exceeds observational limits. The standard solution of the problem invokes inflation occurring after monopole production, diluting their density to undetectable levels and eliminating any possibility of present-day observation. Here, we propose an alternative solution based on the breaking, in the early universe prior to big bang nucleosynthesis, of the Weyl conformal symmetry of the gauge kinetic sector of the Lagrangian. This mechanism enhances monopole annihilation, thereby reducing their abundance to acceptable levels without requiring inflation. This scenario also predicts a residual flux of Grand Unified Theories monopoles potentially within the sensitivity of current and upcoming cosmic ray detectors, making their discovery possible in the near future.

The periodic solution of the Friedmann equation in conformal time implies that only cosmological perturbations exhibiting corresponding symmetries are physically permissible, leading to a discrete spectrum of allowed wave vectors. Furthermore, in a spatially closed universe, these wave vectors are independently constrained to be integers. Matching these two distinct quantization conditions provides a novel theoretical constraint on the possible values of spatial curvature. In this work, we numerically solve the cosmological perturbation equations, incorporating radiation anisotropy and higher-order Boltzmann terms, to calculate these discrete wave vectors with improved precision. Subsequently, we generate cosmic microwave background power spectra for different characteristic spacings of these quantized wave vectors. Finally, we apply the constraint to Planck 2018 observational data to determine the cosmological parameters. This analysis yields a discrete set of allowed values for the spatial curvature, ${\mathrm{\Omega }}_{K,0}$, including $[-0.076,-0.039,-0.024,-0.016,-0.012,\dots ]$.

We study the spatial distributions of pressure, energy density, and shear forces inside the nucleon within the two-flavor Skyrme model including vector mesons. This framework has the advantage that nucleon configurations can be stabilized without the Skyrme term. In contrast to the model without vector mesons, however, we realize that the energy-momentum tensor (EMT) becomes pseudogauge dependent. We explicitly demonstrate that all these distributions differ between the canonical and Belinfante forms of the EMTs. We identify the pseudogauge ambiguity as originating from nonvanishing surface terms associated with spin currents generated by the vector-meson field strength tensors. Furthermore, we show that the pressure and shear-force distributions in the canonical EMT develop singularities at the nucleon center, whereas the corresponding Belinfante distributions remain finite. Finally, we discuss the implications of pseudogauge dependence for extracting the confining force and for constructing the equation of state inside the nucleon.

We study the sensitivity to the decay of a heavy neutral lepton into $e^{+}{e}^{-}$-pairs using the solar boron-8 neutrino flux as source. We provide a fully differential cross section for this process including the interference of neutral and charged current amplitudes. We revisit a previous bound from Borexino and make predictions for the expected sensitivity in future large liquid noble gas detectors, like XLZD, Argo, and DUNE, as well as high-resolution scintillator detectors based on the LiquidO technology. We find that more than two orders of magnitude improvement in mixing angle reach is possible relative to existing bounds.

We investigate a grand unification inspired version of the minimal supersymmetric standard model (MSSM) based on a left-right symmetric $4\text{−}2\text{−}2$ gauge group, incorporating Yukawa coupling unification and current phenomenological constraints. Utilizing a split soft supersymmetry-breaking parameter space motivated by flavor symmetries, we analyze the implications of recent results from ATLAS, CMS, LHCb, and dark matter direct detection experiments. Our numerical scans, conducted with sarah and spheno, identify viable low-energy regions consistent with third-generation Yukawa unification, the observed Higgs boson mass, dark matter relic density, and flavor observables such as $B\to X_s\gamma$, $B_s\to {\mu }^{+}{\mu }^{-}$ and $B_u\to \tau {\nu }_{\tau }$. Our findings suggest that while current bounds severely constrain much of the MSSM-like parameter space, substantial regions remain experimentally viable and testable in the ongoing LHC run and next-generation dark matter experiments.

We propose novel approaches to investigate exotic spin-dependent interactions, $V_{4+5}$ and $V_{12+13}$, between polarized electrons and unpolarized nucleons. A rotating torsion balance is used as the detection apparatus. The pendulum serves as the source of polarized electrons. It comprises a cubic samarium cobalt (${\mathrm{SmCo}}_5$) magnet surrounded by six iron (Fe) pieces, providing approximately $1\times {10}^{23}$ polarized electrons. Tungsten nucleon sources are symmetrically positioned on both sides of the pendulum. $V_{4+5}$ is detected by rotating the nucleon sources about the horizontal axis, while $V_{12+13}$ is detected by rotating them about the vertical axis. After a comprehensive evaluation of random noise and systematic effects, the sensitivity for detecting external torques can reach $1.2\times {10}^{-18}\mathrm{N}·\mathrm{m}$. This sensitivity enables new constraints on the coupling parameters $f_{4+5}^{en}$ and $f_{12+13}^{en}$ for interaction ranges from 0.1 to $10\mathrm{\mu }\mathrm{eV}$. These constraints are expected to improve previous limits by factors of 4 and 170, respectively.

The pion light-cone distribution amplitude (LCDA) is an essential nonperturbative input for a range of high-energy exclusive processes in quantum chromodynamics. Building on our previous work, the continuum limit of the fourth Mellin moment of the pion LCDA is determined in quenched QCD using quark masses which correspond to a pion mass of $m_{\pi }=550\mathrm{MeV}$. This calculation finds $⟨{\xi }^2⟩=0.202(8)(9)$ and $⟨{\xi }^4⟩=0.039(28)(11)$ where the first error indicates the combined statistical and systematic uncertainty from the analysis and the second indicates the uncertainty from working with Wilson coefficients computed to next-to-leading order. These results are presented in the $\overline{\mathrm{MS}}$ scheme at a renormalization scale of $\mu =2\mathrm{GeV}$.

Two-photon exchange (TPE) is one of the leading explanations for discrepancies in measurements of the proton electromagnetic form factors. It has been proposed that TPE could impact not only elastic scattering but also the cross sections for both inclusive deep inelastic scattering (DIS) and semi-inclusive DIS, thereby affecting the interpretation of DIS structure functions in terms of parton distributions. It is expected that higher-order QED effects such as TPE should manifest as a deviation from unity in the ratio of $e^{+}p$ and $e^{-}p$ DIS cross sections. We use the existing inclusive $e^{\pm }p$ DIS data from HERA and SLAC to constrain higher-order QED effects on inclusive DIS.

In this work, we employ the quark-meson coupling model to investigate the mass shifts of $1P$-wave charmonia ${\chi }_{cJ}(1P)$ ($J=0$, 1, 2) in cold symmetric nuclear matter by incorporating in-medium loop contributions to the ${\chi }_{cJ}(1P)$ self-energy within the unquenched picture. At normal nuclear matter density, we obtain significant mass reductions of about 60 MeV for the ${\chi }_{cJ}(1P)$ states, with the ${\chi }_{c2}(1P)$ mass shift primarily arising from the vector-vector loop. Our results also indicate the absence of level crossing between the in-medium ${\chi }_{cJ}(1P)$ mass and the $D\overline{D}$ mass threshold up to ${\rho }_B<3{\rho }_0$—a feature that could be probed in the compressed baryonic matter experiment at FAIR and the beam energy scan program at RHIC.

We study the energy dependence of the cross section for exclusive photoproduction of vector mesons $J/\psi$ and $\mathrm{\Upsilon }$, using a solution to the next-to-leading order (NLO) Balitsky-Fadin-Kuraev-Lipatov (BFKL) equation. Our goal is to use BFKL evolution as a benchmark to provide evidence for the presence of nonlinear QCD dynamics and signs for the onset of gluon saturation at the highest center-of-mass energies. Our approach determines initial conditions for the proton from the Bartels-Golec Biernat-Kowalski (BGK) dipole model and evolves the resulting unintegrated gluon distribution using NLO BFKL evolution. For the nucleus, initial conditions are generated through both the impact parameter dependent saturation model (IP-Sat), using a Wood-Saxon distribution, and a $A^{1/3}$ scaling of the saturation scale of the original BGK model. We find that NLO BFKL evolution provides a very good description of the nuclear modification factor for $J/\psi$ production if initial conditions are generated through an $A^{1/3}$ scaled BGK model, while the description fails if initial conditions are created using the IP-Sat model.

We investigate the general susceptibilities in the charm sector by using the van der Waals hadron resonance gas model (VDWHRG).We argue that the ideal hadron resonance gas, which assumes no interactions between hadrons, and the excluded volume hadron resonance gas, which includes only repulsive interactions, fail to explain the lattice quantum chromodynamics (lQCD) data at very high temperatures. In contrast, the VDWHRG model, incorporating both attractive and repulsive interactions, extends the degree of agreement with lQCD up to nearly 180 MeV. We estimate the partial pressure in the charm sector and study charm susceptibility ratios in a baryon-rich environment, which is tricky for lQCD due to the fermion sign problem. Our study further solidifies the notion that the hadrons should not be treated as noninteracting particles, especially when studying higher order fluctuations, but rather one should consider both attractive and repulsive interactions between the hadrons.

We investigate the Gross–Llewellyn Smith sum rule within the framework of analytic quantum chromodynamics (QCD). A comparison is performed between experimental data, lattice calculations, and perturbative QCD based on conventional and analytic versions of perturbation theory with different parametrizations for the higher twist contributions. We show that conventional perturbation theory fails to reproduce the data, while the analytic version demonstrates good agreement with experiment and lattice calculations. We also discuss the relation between the Gross–Llewellyn Smith sum rule and the Bjorken sum rule.

The gradients act as invisible engines of transport, converting microscopic imbalances into macroscopic flows and, thus, providing deep insights into the dynamics of physical systems. Thermal gradients do not merely drive the flow of heat, but they also set the microscopic constituents of the system into motion. In such scenarios, the constituents of the system not only transport energy, but also diffuse collectively under the influence of these gradients. For the very first time, we present a first-principles investigation of the Soret and Dufour effects in hot and dense QCD matter. We use the relativistic Boltzmann transport equation under the relaxation time approximation. By incorporating chemical potential and temperature gradients into the kinetic theory framework, we derive explicit expressions for the Dufour coefficient, which quantifies the heat flow due to concentration gradients, and the Soret coefficient, which describes the particle diffusion induced by thermal gradients. These coupled-transport phenomena are traditionally studied in multicomponent classical systems at low energy scales. In this study, we follow quasiparticle models for the deconfined phase and the hadron resonance gas model for the confined hadronic phase in the context of heavy-ion collisions. This study provides novel insights into the thermodiffusion and diffusion-thermo phenomena and opens avenues for incorporating such effects in hydrodynamic modeling and transport simulations of QCD matter.

Spin-1 particles, is a fundamental bound state for the two quarks, and play a crucial role in elucidating the electromagnetic properties within the realm of hadronic physics. Their intrinsic relativistic nature mandates a quantum field theory (QFT) framework for a comprehensive analysis. In this investigation, we employ both the instant form of QFT and light-front quantum field theory (LFQFT) as our theoretical tools. While conventional LFQFT approaches predominantly focus on the plus component of the electromagnetic current to extract the properties of spin-1 vector particles, our study extends this analysis by systematically incorporating the minus component as well. Our findings demonstrate that achieving a rigorous equivalence between these distinct current components necessitates the inclusion of nonvalence terms within the electromagnetic current operator. This crucial inclusion serves to restore manifest covariance and ensures a robust consistency with the results independently derived from the more conventional instant form of quantum field theory.

We present the results of searches for nucleon decays via $p\to \nu {\pi }^{+}$ and $n\to \nu {\pi }^0$ using a $0.484\mathrm{Mt}·\mathrm{yr}$ exposure of Super-Kamiokande I-V data covering the entire pure water phase of the experiment. Various improvements on the previous 2014 nucleon decay search [Phys. Rev. Lett. 113, 121802 (2014)], which used an exposure of $0.173\mathrm{Mt}·\mathrm{yr}$, are incorporated. The physics models related to pion production and nuclear interaction are refined with external data, and a more comprehensive set of systematic uncertainties, now including those associated with the atmospheric neutrino flux and pion production channels, is considered. Also, the fiducial volume has been expanded by 21%. No significant indication of a nucleon decay signal is found beyond the expected background. Lower bounds on the nucleon partial lifetimes are determined to be $3.5\times {10}^{32}\mathrm{yr}$ for $p\to \nu {\pi }^{+}$ and $1.4\times {10}^{33}\mathrm{yr}$ for $n\to \nu {\pi }^0$ at 90% confidence level.

It was recently shown that the time variation of the polarization of electromagnetic waves from pulsars can be used, in cross-correlation with pulsar timing, to probe the chirality of an isotropic gravitational wave background. Here, we show that the expression for the cross-correlation is derived efficiently with the total-angular-momentum formalism and use this framework to extend the formulation to cross-correlation with astrometry. We do so for spin-1 gravitational waves (that may arise in alternative-gravity theories) as well as the general-relativistic spin-2 gravitational waves.