We develop a scenario based on $\mu$-hybrid inflation within the framework of a left-right symmetric model defined by the gauge symmetry group $G_{3221}=SU(3{)}_c\times SU(2{)}_L\times SU(2{)}_R\times U(1{)}_{B-L}$. This model features a two-stage symmetry breaking to the Standard Model, with inflation occurring between the two stages, resulting in the dilution of primordial monopoles produced during the symmetry breaking of $SU(2{)}_R$ to $U(1{)}_R$. The second symmetry breaking gives rise to a network of metastable cosmic strings, which produces gravitational waves that can be observed by current and future experiments. A crucial aspect of this model is the inclusion of $R$-symmetry breaking terms in the superpotential, which helps explain the origin of the first symmetry breaking scale and ensures experimentally viable inflation with a minimal (canonical) Kähler potential. We show that the model successfully implements consistent inflation, leptogenesis, metastable cosmic strings, and gravitino dark matter, all in agreement with the observational data and constraints on reheating temperature from leptogenesis and gravitino overproduction bounds. We explore the potential embedding of $G_{3221}$ within the gauge symmetry $G_{422}=SU(4{)}_c\times SU(2{)}_L\times SU(2{)}_R$ and provide a brief discussion on the proton decay predictions, which can be tested by the upcoming experiments.

Stellar mass, binary black hole (BBH) mergers dominates the sources of gravitational wave (GW) events so far detected by the LIGO/Virgo/KAGRA (LVK) experiment. The origin of these BBHs is unknown, and no electromagnetic (EM) counterpart has been undoubtedly associated to any of such GW events. The thin discs of active galactic nuclei (AGNs) might be viable environments where BBHs can form and at the same time produce observable radiation feedback. This paper presents new physically motivated light-curve (LC) solutions for thermal flares driven by the remnant of a BBH merger within the disc of an AGN. Following previous analyses, we consider that the BBH likely creates an under-density cavity in the disc prior to its coalescence. Depending on the merger conditions, the black hole (BH) remnant can leave the cavity, interact with the unperturbed disc, and drive a transient BH wind. The wind expels disc material that expands above and below the disc plane and we consider the emission of these plasma ejections as the EM counterpart to the merger GW. We model the LC of such eruptions as minisupernovae explosions finding that stellar mass merger remnants can drive distinguishable flares in optical and UV bands, with time lags of $\sim 10–100\mathrm{days}$ after the GW event, when occurring in AGN with central engines of $\sim {10}^{6-8}{M}_{\odot }$. The Vera C. Rubin Observatory can potentially detect the optical component of these EM counterparts up to redshifts of $z\sim 0.7–1.2$, accordingly. The present model provide constraints on multimessenger observables, such as the binary effective spin, mass ratio, remnant mass, and the time delay of the EM signature. These constraints are useful to localize flaring AGNs as sources of multimessenger emission following GW alerts.

Space-based gravitational wave (GW) detectors aim to measure GWs in the millihertz frequency band. Various noise sources can limit the GW detection sensitivity during the detection process. Tilt-to-length (TTL) noise, arising from the angular and lateral jitter of spacecraft (SC) and movable optical subassembly (MOSA), is one of the primary noise sources remaining after using the time-delay interferometry (TDI) technique to suppress laser frequency noise. In this paper, we derive an analytical expression for the TTL noise power spectral density (PSD) in arbitrary geometric TDI combinations. Moreover, we calculate the signal-to-noise ratio (SNR) of TTL noise to the noise floor (test mass acceleration noise and optical path noise) and find that the SNR exceeds 1 in the frequency band of 2 mHz to 1 Hz. Then, we construct a marginal likelihood function to estimate TTL coupling coefficients from the unknown noise floor PSD and unknown GW signals. This approach uses these estimated coefficients to subtract TTL noise. We use a simulation to show that TTL coupling coefficients estimation error is less than $0.1\mathrm{mm}/\mathrm{rad}$ for forty-five geometric TDI combinations, and the suppressed TTL noise level is below the noise floor. Finally, a frequency-domain burst is injected to verify the algorithm’s robustness. We compare the estimation accuracy of the marginal likelihood estimation with that of the least squares method. Our work shows that the marginal likelihood estimation effectively subtracts TTL noise and demonstrates stronger robustness in the presence of an unexpected frequency-domain burst.

We calculate $(\sqrt{-t}/Q{)}^k$ and $(m/Q{)}^k$ power corrections with $k\le 4$, where $m$ is the target mass and $t$ is the momentum transfer, to several key observables in deeply virtual Compton scattering (DVCS). We find that the power expansion is well convergent up to $|t|/Q^2\lesssim 1/4$ for most of the observables, but is naturally organized in terms of $1/(Q^2+t)$ rather than the nominal hard scale $1/Q^2$. We also argue that target mass corrections remain under control and do not endanger quantum chromodynamics (QCD) factorization for coherent DVCS on nuclei. These results remove an important source of uncertainties due to the frame dependence and violation of electromagnetic Ward identities in the QCD predictions for the DVCS amplitudes in the leading-twist approximation.

Inspired by the newly observed $T_{c\overline{s}}$ state in the $D_{s1}(2460{)}^{+}\to D_s^{+}{\pi }^{+}{\pi }^{-}$ reaction by the LHCb Collaboration, we investigate the amplitude of this decay to explore the origins and properties of the open-charm tetraquark state based on the final state interaction. The invariant mass distributions of $D_s^{+}{\pi }^{+}$ and ${\pi }^{+}{\pi }^{-}$ are well reproduced by the $S$-wave scattering amplitudes of the coupled channel systems $D_s\pi$ and $\pi \pi$. However, neither the tree level nor both the tree level and $\pi \pi$ coupled channel scattering contributions can describe the experimental data well, which indicates that the $D_s\pi$ coupled channel scattering is required. We find that the $T_{c\overline{s}}$ and $f_0(500)$ resonances are dynamically generated from the pseudoscalar-pseudoscalar meson interaction within the chiral unitary approach. In addition, we find the corresponding poles and also calculate the $S$-wave scattering length for the $DK$ channel, which is on the same scale as the result extracted from the experiment. We propose that the $T_{c\overline{s}}$ and $f_0(500)$ resonances in the $D_{s1}(2460{)}^{+}\to D_s^{+}{\pi }^{+}{\pi }^{-}$ reaction are hadronic molecular type particles.

We examine the behavior of singular leading and subleading logarithms, commonly referred to as the soft-virtual (SV) and next-to-soft-virtual (NSV) terms, in the production of the Higgs boson via the bottom quark annihilation channel. We derive analytic expressions at the SV + NSV resummed level, up to next-to-next-to-next-to-leading logarithmic (N3LL) accuracy in perturbative quantum chromodynamics (QCD), applicable to both the inclusive production cross section and rapidity distribution. This has been achieved using an existing resummation formalism based on factorization and renormalization group (RG) invariance. A phenomenological analysis of our resummed results is performed for the 13 TeV Large Hadron Collider. Furthermore, we present the SV coefficients at the fourth order in the strong coupling and explore the impact of next-to-next-to-next-to-next-to-leading logarithmic (N4LL) resummation on the total cross section.

We study the longitudinal spin polarization of a relativistic fluid of massive spin-$1/2$ particles undergoing a boost-invariant expansion in the longitudinal direction and rotating in the transverse plane. We express the polarization vector in terms of spin moments and derive closed equations of motion for the latter using spin kinetic theory with a nonlocal relaxation time approximation. These equations of motion are valid at any time of the evolution, from the free-streaming regime to the hydrodynamic regime. At late time, the polarization features contributions from gradients of the fluid velocity and of the temperature that emerge from the nonlocal part of the collision term. Our results can be used to explore polarization phenomena in the context of heavy-ion collisions.

In this work, we investigate the semileptonic decays of the $B_{(s)}$ meson to $D_0^{*}(2300)$, $D_{s0}^{*}(2317)$, $D_{s1}(2460)$, $D_{s1}(2536)$, $D_1(2420)$, and $D_1(2430)$ in the covariant light-front quark model. We combine the helicity amplitudes via the corresponding form factors to obtain the branching ratios of the semileptonic decays $B_{(s)}\to D_{(s)}^{**}\ell {\nu }_{\ell }$ with $D_{(s)}^{**}$ referring to a P-wave excited charmed meson $D_0^{*}(2300)$, $D_{s0}^{*}(2317)$, $D_{s1}(2460)$, $D_{s1}(2536)$, $D_1(2420)$, or $D_1(2430)$ and $\ell =e$, $\mu$, $\tau$. Furthermore, we also take into account another two physical observables, namely, the longitudinal polarization fraction $f_L$ and the forward-backward asymmetry $A_{FB}$. Most of our predictions are comparable to the results given by other theoretical approaches and the currently available data. The branching ratios of the semileptonic decay channels $B_s\to D_{s1}(2460)\ell {\nu }_{\ell }$ and $B\to D_1(2420)\ell {\nu }_{\ell }$ are larger than those of the semileptonic decays $B_s\to D_{s1}(2536)\ell {\nu }_{\ell }$ and $B\to D_1(2430)\ell {\nu }_{\ell }$, respectively. We find that the long-standing “$1/2$ vs $3/2$ puzzle” in the decays $B^{+}\to {\overline{D}}_1^{(\prime )0}{\ell }^{\prime +}{\nu }_{{\ell }^{\prime }}$ $({\ell }^{\prime }=e,\mu )$ can be solved by taking some negative mixing angle ${\theta }_s$ values within a range from $-30.3°$ to $-24.9°$, corresponding to $\theta$ of about $5°\sim 10.4°$; whereas the Belle Collaboration updated their measurements for the decays $B^0\to D_0^{*-}{\ell }^{\prime +}{\nu }_{{\ell }^{\prime }}$ with only a small upper limit $\mathrm{Br}(B^0\to D_0^{*-}{\ell }^{\prime +}{\nu }_{{\ell }^{\prime }})<0.44\times {10}^{-3}$ obtained, which is much larger than most theoretical predictions and raises a new puzzle.

With no concrete evidence for nongravitational interactions of dark matter to date, it is natural to wonder whether dark matter couples predominantly to the Standard Model (SM)’s neutrinos. Neutrino interactions (and the possible existence of additional neutrinophilic mediators) are substantially less understood than those of other SM particles, yet this picture will change dramatically in the coming decades with new neutrino sources. One potential new source arises with the construction of a high-energy muon collider (MuCol); due to muons’ instability, a MuCol is a source of high-energy collimated neutrinos. Importantly, since the physics of muon decays (into neutrinos) is very well-understood, this leads to a neutrino flux with systematic uncertainties far smaller than fluxes from conventional high-energy (proton-sourced) neutrino beams. In this work, we study the capabilities of a potential neutrino detector, “$\mathrm{MuCol}\nu$”, placed $\sim 100\mathrm{m}$ downstream of the MuCol interaction point. The $\mathrm{MuCol}\nu$ detector would be especially capable of searching for a neutrinophilic mediator $\varphi$ through the mononeutrino scattering process ${\nu }_{\mu }N\to {\mu }^{+}\varphi X$, exceeding searches from other terrestrial approaches for $m_{\varphi }$ in the $\sim \mathrm{few}$ MeV- ten GeV range. Even with a 10 kg-yr exposure, $\mathrm{MuCol}\nu$ is capable of searching for well-motivated classes of thermal freeze-out and freeze-in neutrino-portal dark matter.

The kinetic mixing (KM) portal, by which the Standard Model (SM) photon mixes with a light dark photon arising from a new $U(1{)}_D$ gauge group, allows for the possibility of viable scenarios of sub-GeV thermal dark matter with appropriately suppressed couplings to the SM. This KM can only occur if particles having both SM and dark quantum numbers, here termed portal matter, also exist. The presence of such types of states and the strong suggestion of a need to embed $U(1{)}_D$ into a non-Abelian gauge structure not too far above the TeV scale based on the renormalization-group equation running of the $U(1{)}_D$ gauge coupling is potentially indicative of an enlarged group linking together the visible and dark sectors. The gauge group $G=SU(3{)}_c\times SU(3{)}_L\times U(1{)}_A\times U(1{)}_B=3_c{3}_L{1}_A{1}_B$ is perhaps the simplest setup wherein the SM and dark interactions are partially unified in a non-Abelian fashion that is not a simple product group of the form $G=G_{\mathrm{SM}}\times G_D$ encountered frequently in earlier work. The present paper describes the implications and phenomenology of this type of setup.

In the theory with a Majorana fermion ($\mathcal{X}$) coupled to quarklike fermions ($Q$) via a dimension-six four-fermion vector-vector interaction, we have computed in an earlier work the baryon asymmetry generated in the decay and scattering processes of the $\mathcal{X}$ with $Q$. In this work we consider such processes in the expanding early Universe, set up the Boltzmann equations governing the $\mathcal{X}$ and net baryon number densities, and numerically solve them in example benchmark points, taking the thermally averaged decay and scattering rates and their temperature dependence from the earlier study. We find that starting from a baryon symmetric universe at early time, the presently observed baryon asymmetry of the universe (BAU) can be explained in this theory over a wide range of mass scales, $M_{\chi }\in ({10}^4,{10}^{16})\mathrm{GeV}$ for appropriately chosen couplings. We find that scattering processes play a crucial role in generating the baryon asymmetry in this theory. We present our results in a general manner that should be useful not just in our theory, but also in other related theories that share the essential ingredients. Our results should help guide promising ways to probe such new physics in terrestrial experiments. For instance, in regions of parameter space that yield the observed BAU, we present the rate for neutron-antineutron ($n-\overline{n}$) oscillation and discuss the prospects for observing this in upcoming experiments.

The axionlike particle (ALP) is one of the best motivated particles beyond the Standard Model (SM). We explore the possibility of detecting the couplings of ALP with leptons via three-lepton final state processes $e^{-}p\to e^{-}ja(a\to {\ell }^{+}{\ell }^{-})$ at the LHeC (FCC-eh). For completeness, we investigate the cases where the ALP decays not only into electron and muon pairs but also into tau pairs, and perform a detailed simulation for the decays of taus. We find that the prospective sensitivities of the LHeC (FCC-eh) with the center-of-mass energy $\sqrt{s}=1.3(3.5)\mathrm{TeV}$ and the integrated luminosity $\mathcal{L}=1(2){\mathrm{ab}}^{-1}$ to the ALP-lepton couplings are not only stronger than some existing bounds of the LHC and LEP but also complementary to the expected bounds of the CEPC and FCC-ee.

In this paper, we investigate the scattering of Bogomolny-Prasad-Sommerfield (BPS) magnetic monopoles through numerical simulations. We present an ansatz for various multimonopole configurations suitable for analyzing monopole scattering processes. Our study includes planar scattering scenarios involving two, three, and four monopoles, as well as nonplanar processes where three and four monopoles form intermediate tetrahedral and cubic states, respectively. Our observations align with the theoretical predictions of the moduli space approximation. Furthermore, we extend our analysis to relativistic velocities and explore parameters beyond the BPS limit.

We report the results of an extensive numerical study of the $Sp(4)$ lattice gauge theory coupled to fermion matter content consisting of three (Dirac) flavors, transforming in the two-index antisymmetric representation of the gauge group. In the presence of (degenerate) fermion masses, the theory has an enhanced global $SU(6)$ symmetry, broken explicitly and spontaneously to its $SO(6)$ subgroup. This symmetry breaking pattern makes the theory interesting for applications in the context of composite Higgs models, as well as for the implementation of top partial compositeness. Alternatively, it can also provide a dynamical realization of the strongly interacting massive particle paradigm for the origin of dark matter. We adopt the standard plaquette gauge action, along with the Wilson-Dirac formulation for the fermions, and apply the (rational) hybrid Monte Carlo algorithm in our ensemble generation process. We monitor the autocorrelation and topology of the ensembles. We explore the bare parameter space, and identify the weak and strong coupling regimes, which are separated by a line of first-order bulk phase transitions.

We measure two-point correlation functions between meson operators that transform as nontrivial representations of $SO(6)$, and extract the ground-state masses, in all accessible spin and parity channels. We assess the size of finite volume effects, and restrict attention to measurements in which these systematic effects are negligibly small compared to the statistical uncertainties. The accuracy of our data enables us to extract the decay constants of the composite particles in the pseudoscalar, vector and axial-vector channels. In addition, we measure the mass of the first excited state for one of the channels, the vector meson, by performing a generalized eigenvalue problem analysis involving two different meson operators. Spectral quantities show a mass dependence that is compatible with the expectation that, at long distances, the theory undergoes confinement, accompanied by the spontaneous breaking of the approximate global symmetries acting on the matter fields. Finally, we discuss the continuum and massless extrapolations within the framework of Wilson chiral perturbation theory, after setting the physical scale using the gradient flow method, and compare the results to those of existing studies in the quenched approximation, as well as to the literature on closely related theories.

Lattice quantum chromodynamics (QCD) calculations share a defining challenge by requiring a small finite range of spatial separation $z$ between quark/gluon bilinears for controllable power corrections in the perturbative QCD factorization, and a large hadron boost $p_z$ for a successful determination of collinear parton distribution functions (PDFs). However, these two requirements make the determination of PDFs from lattice data very challenging. We present the application of generative machine learning algorithms to estimate the polarized and unpolarized gluon correlation functions utilizing short-distance data and extending the correlation up to $z{p}_z\lesssim 14$, surpassing the current capabilities of lattice QCD calculations. We train physics-informed machine learning algorithms to learn from the short-distance correlation at $z\lesssim 0.36\mathrm{fm}$ and take the limit, $p_z\to \infty$, thereby minimizing possible contamination from the higher-twist effects for a successful reconstruction of the polarized gluon PDF. We also expose the bias and problems with underestimating uncertainties associated with the use of model-dependent and overly constrained functional forms, such as $x^{\alpha }(1-x{)}^{\beta }$ and its variants to extract PDFs from the lattice data. We propose the use of generative machine learning algorithms to mitigate these issues and present our determination of the polarized and unpolarized gluon PDFs in the nucleon.

We develop a generalization of low-mode averaging in which the number of low quark modes of the Dirac operator required for a constant variance reduction can be kept independent of the volume by exploiting their local coherence. Typically in lattice QCD simulations, the benefit of translation averaging quark propagators over the space-time volume is spoiled by large fluctuations introduced by the approximations needed to estimate the average. For quark-line connected diagrams at large separations, most of this additional variance can be efficiently suppressed by the introduction of hierarchical subspaces, thanks to the reduced size of the coarse grid operators that act within the subspaces. In this work, we investigate the contributions to the variance of the isovector vector current correlator with $N_{\mathrm{f}}=2$ nonperturbatively $\mathrm{O}(a)$-improved Wilson fermions on lattices approximately of size $L=2$, 3 and 4 fm. The numerical results obtained confirm that the variance decreases as the volume is increased when a multigrid decomposition is used with a fixed number of low modes. We obtain a speedup of more than an order of magnitude compared with a plain stochastic estimator. Compared with state-of-the-art low-mode averaging we practically eliminate the cost of generating low modes and the associated memory and storage overheads. While the proposed decomposition can be applied to any quark propagator, it is expected to be especially effective for quark-line connected diagrams at large separations, for example, the isovector contribution to the hadronic vacuum polarization or baryonic correlators.

We investigate the photoproduction of neutral $\rho$ mesons in ultraperipheral isobaric collisions of ${}_{44}{}^{96}\mathrm{Ru}+{}_{44}{}^{96}\mathrm{Ru}$ and ${}_{40}{}^{96}\mathrm{Zr}+{}_{40}{}^{96}\mathrm{Zr}$ at $s_{NN}^{1/2}=200\mathrm{GeV}$, employing the dipole model within the equivalent photon approximation. By implementing the Woods-Saxon distribution for the nuclear mass density, which is derived from the density functional theory incorporating nuclear deformation effects, we calculate differential cross sections in $\mathrm{Ru}+\mathrm{Ru}$ and $\mathrm{Zr}+\mathrm{Zr}$ collisions as well as their ratios in the transverse momentum spectrum squared $q_T^2$. We observe the characteristic dip behavior in differential cross sections, an indicator of diffraction in high-energy collisions. When nuclear deformation is considered, the ratio of differential cross sections shows a nearly linear increase behavior with increasing $q_T^2$ for $q_T^2\lesssim 0.015{\mathrm{GeV}}^2$, in agreement with experimental observation. We offer a simple explanation for such a behavior by introducing an effective description of the thickness function. We also extend our discussion on the photoproduction of neutral $\rho$ mesons in electron-ion collisions with nuclear targets Cu-63, Au-197 and U-238.

We conduct an investigation on the spin $\frac{3}{2}\to \frac{1}{2}$ semileptonic weak transition of single heavy baryons for the exclusive decay ${\mathrm{\Sigma }}_b^{*0}\to {\mathrm{\Sigma }}_c^{+}\ell {\overline{\nu }}_{\ell }$ in three possible lepton channels within the three point QCD sum rule method. We compute the responsible form factors of this semileptonic decay by incorporating both perturbative and nonperturbative contributions of the operator product expansion series up to a mass dimension six. Having acquired the form factors, the decay widths of the processes in all lepton channels are determined. Our findings as well as possible future experimental information can be employed in order to check the SM predictions and explore the possibility of new physics in heavy baryonic decay channels.

The role of finite volume effects on the various transport coefficients of strongly interacting quark matter is analyzed in the Polyakov chiral SU(3) quark mean-field model at finite temperatures and chemical potentials incorporating the fermionic vacuum term. Using a nonzero lower momentum cutoff and two different forms of the Polyakov loop potentials with quark backreaction, we study the following viscous properties: specific shear viscosity ($\eta /s$), normalized bulk viscosity (${\zeta }_b/s$), and conductivity properties: electrical conductivity (${\sigma }_{\mathrm{el}}/T$) and thermal conductivity ($\kappa /T^2$). Along with this, some essential thermodynamic quantities in the context of transport properties, such as the square of the speed of sound ($c_s^2$) and the specific heat ($c_v$) at a constant volume, are computed. Finite size effects are applied to the vacuum term and its influence on the effective quark masses, thermodynamic quantities, and transport coefficients is studied. The temperature dependence of the transport coefficients is obtained through the kinetic theory approach with the relaxation time approximation. The size of the system has been found to have significant effects on all transport coefficients. We find that all the transport coefficients increase as the size of the system is reduced. We have also studied the specific sound channel $(\eta +3{\zeta }_b/4)/s$ and the bulk-to-shear viscosity ratio ${\zeta }_b/\eta$. The effect of finite size is found to be more prominent in the transition region and vanishes at high $T$. The transition temperature $T_{\chi }$ is found to decrease as the system size (characterized by $R$) decreases. At finite chemical potentials, $T_{\chi }$ is shifted to lower values compared to the case of the vanishing chemical potential.

We revisit the isospin-breaking corrections relating the $e^{+}{e}^{-}$ hadronic cross section and the tau decay spectral function, focusing on the dipion channel, that gives the dominant contribution to the hadronic vacuum polarization piece of the muon $g-2$. We test different types of electromagnetic and weak form factors and show that both, the Gounaris-Sakurai and a dispersive-based approach, describe accurately $\tau$ lepton and $e^{+}{e}^{-}$ data (less when KLOE measurements are included in the fits) and comply reasonably well with analyticity constraints. From these results we obtain the isospin-breaking contribution to the conserved vector current (CVC) prediction of the $\mathrm{BR}(\tau \to \pi \pi {\nu }_{\tau })$ and to the $2\pi$ hadronic vacuum polarization (HVP) contribution to the muon $g-2$, in agreement with previous determinations and with similar precision. Our results abound in the utility of using tau data-based results in the updated data-driven prediction of the muon $g-2$ in the Standard Model.