The space-borne gravitational wave (GW) detection mission endeavors to uncover more abundant GW sources within the frequency range of 0.1 mHz to 1 Hz. Given the inherently feeble nature of GW signals, they are often overshadowed by lots of noise sources. Among these, laser frequency noise and clock-jitter noise stand out as the primary obstacles in space-borne GW detection. To mitigate these noises, a postprocessing technique known as time-delay interferometry (TDI) has been proposed. Additionally, arm locking has emerged as a promising method to attenuate laser frequency noise by several orders of magnitude, thereby alleviating the challenges posed by TDI. Both theoretical and experimental evidence underscores the viability of this method. In this paper, we extend the application of arm locking to address the clock-jitter noise. In the space-borne GW detection, an interspacecraft clock transfer chain leveraging electro-optic modulator (EOM) sideband modulation is employed to facilitate the comparison of clock noises between spacecrafts. This comparison data can serve as an error signal and be used to control the clock signal, which is similar to the intersatellite laser phase-locking technology. Furthermore, we propose locking the clock frequency to the arm length of the GW detector, and delve into the methodology and identify the typical noise sources. Our findings reveal that within the scientific frequency band, clock-jitter noise can be suppressed by at least three orders of magnitude, thereby satisfying the stringent requirements of space-borne GW detection. At the same time, it also means that a highly stable clock can be effectively generated from a hardware perspective.

Gravitational-wave data from interferometric detectors like LIGO, Virgo and KAGRA are routinely analyzed by rapid matched-filtering algorithms to detect compact binary merger events and rapidly infer their spatial position, which enables the discovery of associated transients like GRB 170817A and AT2017gfo. One of the critical requirements for finding such counterparts is that the rapidly inferred sky location, usually performed by the bayestar algorithm, is correct. The reliability of this data product relies on various assumptions and a tuning parameter in bayestar, which we investigate in this paper in the context of PyCBC Live, one of the rapid search algorithms used by LIGO, Virgo and KAGRA. We perform simulations of compact binary coalescence signals recovered by PyCBC Live and localized by bayestar, under various configurations with different balances between simplicity and realism, and we test the resulting sky localizations for consistency based on the widely-used percentile-percentile plot. We identify some aspects of the search configuration which drive the optimal setting of bayestar’s tuning parameter, in particular the properties of the template bank used for matched filtering. On the other hand, we find that this parameter does not depend strongly on the nonstationary and non-Gaussian properties of the detector noise.

We investigate the purely nonfactorizable ${\mathrm{\Lambda }}_c^{+}\to {\mathrm{\Xi }}^0{K}^{+}$ decay using light-cone sum rules. To extract the decay amplitudes, a three-point correlation function is defined and calculated at hadron and quark-gluon level, respectively. Both the W-exchange and the W-inward emission diagrams are considered in the quark-gluon level calculation, where the two-particle light-cone distribution amplitudes (LCDAs) of kaon are used as nonperturbative input. We obtain the decay amplitudes contributed from the twist-2 and twist-3 kaon LCDAs, respectively. The obtained P-wave amplitude is consistent with those predicted in the literature, while the S-wave one is much smaller. This significant difference between the S- and P -wave amplitudes leads to small up-down spin asymmetry, close to the experimental measurement.

Analysis of normalized $C$ moments of multiplicity distribution calculated from the different phenomenological models, the Bialas-Praszalowics (BP) model, modified negative binomial and the superposed shifted Gompertz distribution at different center of mass (cms) energies is presented. The analysis covers a range of energies (200–900 GeV) of $\overline{p}p$ collisions in restricted phase space slices. A comparison of different models to the experimental data on charged particle multiplicity spectra from the $\overline{p}p$ annihilation in five pseudorapidity windows is reported. The comparison shows that the two approaches other than the BP model are in better agreement to the data. Results on variation of moments with pseudorapidity window size and with center of mass energy and observations from such a study in $\overline{p}p$ annihilation and $pp$ interactions at the same center-of-mass energy are also presented.

This paper addresses Yukawa theory, focusing on the scattering between two identical fermions mediated by an intermediate scalar boson, considering the effects of thermal contributions and Lorentz symmetry breaking. Temperature is introduced into the theory through the thermofield dynamics formalism, while Lorentz violation arises from a background tensor coupled to the kinetic part of the Klein-Gordon Lagrangian. Two important quantities are calculated: the cross section for the scattering process and the modified Yukawa potential. The main results obtained in this work demonstrate that considering Lorentz symmetry breaking has several implications for changes in symmetries and physical states, while the presence of temperature is strongly related to the strength of the interaction. This interplay between symmetry breaking and temperature effects provides deeper insights into the behavior of the Yukawa theory under different conditions.

We analyze lepton flavor violation (LFV) using the Standard Model effective field theory (SMEFT) framework at the future lepton colliders. Our focus is on the associated production of tau lepton with electron/muon at the electron-positron ($e^{+}{e}^{-}$) colliders, related to four-Fermi SMEFT effective operators. In accordance with the upper limits on effective couplings from lepton flavor violating tau decays, we conduct a cut-based analysis to achieve sufficient signal significance. We utilize the optimal observable technique (OOT) to estimate the optimal sensitivity of the effective couplings. The impact of electron beam polarization and the interplay of signal and background in enhancing the optimal sensitivity of the effective couplings are discussed in detail. We find that the sensitivity of flavor-violating effective couplings is enhanced by order of one for 3 TeV center-of-mass (CM) energy and $1000{\mathrm{fb}}^{-1}$ integrated luminosity at the $e^{+}{e}^{-}$ colliders.

We examine the possibility that dark matter (DM) may be an ultralight scalar that was misaligned via nonminimal coupling to gravity, in the early Universe. For a certain regime of scalar masses, gravitational effects in neutron stars could place interesting bounds on the viable parameter space of the model, even in the absence of nongravitational interactions between DM and ordinary matter.

A possible extension of the Standard Model able to explain the recent measurement of the anomalous magnetic moment of the muon consists in adding a gauged $U(1{)}_{L_{\mu }-L_{\tau }}$ symmetry. If the dark matter particle is charged under this symmetry, then the kinetic mixing between the new gauge boson and the photon induces dark matter-electron interactions. We derive direct detection constraints on light dark matter charged under a $U(1{)}_{L_{\mu }-L_{\tau }}$ symmetry with electron recoil experiments and explore prospects with XLZD and OSCURA to close in the parameter space able to explain simultaneously the recent measurement on the anomalous magnetic moment of the muon and the observed relic density of dark matter. We further discuss the spin-dependent scattering contribution arising in this model, which was ignored previously in the literature.

The production of multiple Higgs bosons at the LHC and beyond is a strong test of the mechanism of electroweak symmetry breaking. Taking inspiration from recent experimental efforts to move toward limits on triple-Higgs production at the Large Hadron Collider, we consider generic bosonic deviations of $HH$ and $HHH$ production from the Standard Model in the guise of Higgs effective field theory (HEFT). Including one-loop radiative corrections within the HEFT and going up to $\mathcal{O}(p^4)$ in the momentum expansion, we provide a detailed motivation of the parameter range that the LHC (and future hadron colliders) can explore, through accessing nonstandard coupling modifications and momentum dependencies that probe Higgs boson nonlinearities. In particular, we find that radiative corrections can enhance the sensitivity to Higgs self-coupling modifiers and HEFT-specific momentum dependencies can vastly increase triple-Higgs production, thus providing further motivation to consider these processes during the LHC’s high-luminosity phase.

The $\mathcal{V}\to \mathcal{P}\gamma$ and $\eta ({\eta }^{\prime })\to \gamma \gamma$ decays are evaluated within a Dyson-Schwinger and Bethe-Salpeter equations framework (here $\mathcal{V}=\{{\rho }^{\pm },K^{\star \pm },\varphi \}$ and $\mathcal{P}=\{{\pi }^{\pm },K^{\pm },\eta ,{\eta }^{\prime }\}$). The so-called impulse approximation (IA) is employed in the computation of the decay constants involved and decay widths, and so in the estimation of the associated charge and interaction radii. For their part, the required propagators and vertices stem from a contact interaction model, embedded within a beyond rainbow-ladder (RL) truncation that accounts for the typical ladder exchanges, quark anomalous magnetic moment, as well as the non-Abelian anomaly. While the examined transitions produce decay widths plainly compatible with the available experimental data, those processes involving the $\eta -{\eta }^{\prime }$ mesons highlight the incompleteness of the IA when considering beyond RL effects in the interaction kernels.

We calculate the cross section for forward $\mathrm{J}/\psi$ production in proton-proton and minimum bias proton-lead collisions using the color glass condensate (CGC) and nonrelativistic QCD (NRQCD) formalism consistently with deep inelastic scattering data. The cross section for color singlet states is sensitive to a four-point correlator of Wilson lines for which we describe in the Gaussian approximation in the large-$N_c$ limit. Furthermore, we quantify the importance of finite-$N_{\mathrm{c}}$ corrections to have a small $\sim 12\%$ effect. In contrast with the generic NRQCD expectation, we show that the color singlet contribution is only 15% to the total cross section. We also compare our predictions for $\mathrm{J}/\psi$ production as well as for the nuclear modification ratio $R_{pPb}$ to LHCb and ALICE data. We find a good agreement at forward rapidities, except at low transverse momenta where the cross sections are overestimated.

We propose a novel mechanism that the spin alignment of vector meson $\varphi$ and $K^{*0}$ in most central heavy ion collisions is induced by intrinsic quantum chromo dynamics (QCD) without external vortical/magnetic fields. The local spin density fluctuation of quarks due to the axial-vector and tensor interactions between quarks can induce the spin alignments of vector meson. It is found that axial-vector interaction results in ${\rho }_{00}<1/3$ for the spin alignment of $\varphi$ meson, while tensor interaction results in ${\rho }_{00}>1/3$. We argue that the spin alignment of $K^{*0}$ due to the spin density fluctuation from flavor-mixing would be a signature or hint of instanton.

Nonperturbative inequalities constrain the thermodynamic pressure of quantum chromodynamics (QCD) with its phase-quenched version, a sign-problem-free theory amenable to lattice treatment. In the perturbative regime with a small QCD coupling constant ${\alpha }_s$, one of these inequalities manifests as an $O({\alpha }_s^3)$ difference between the phase-quenched and QCD pressures at large baryon chemical potential. In this work, we generalize state-of-the-art algorithmic techniques used in collider physics to address large-scale multiloop computations at finite chemical potential, by direct numerical integration of Feynman diagrams in momentum space. Using this novel approach, we evaluate this $O({\alpha }_s^3)$ difference and show that it is a gauge-independent and small positive number compared to the known perturbative coefficients at this order. This implies that at high baryon densities, phase-quenched lattice simulations can provide a complementary nonperturbative method for accurately determining the pressure of cold quark matter at $O({\alpha }_s^3)$.

We apply the method of quantum chromodynamics (QCD) sum rules to study the $qc\overline{q}\overline{c}$ tetraquark states with the exotic quantum number $J^{PC}=3^{-+}$, and extract the mass of the lowest-lying state to be ${4.49}_{-0.41}^{+0.45}\mathrm{GeV}$. To construct the relevant tetraquark currents we need to explicitly add the covariant derivative operator. Our systematic analysis of these interpolating currents indicates that: (a) this state readily decays into the $P$-wave $[\rho J/\psi ]/[\omega J/\psi ]$ channel but not into the $[\rho {\chi }_{c2}]/[\omega {\chi }_{c2}]/[J/\psi f_2(1270)]$ channels, and (b) it readily decays into the $[D^{*}{\overline{D}}_2^{*}]$ channel but not into the $P$-wave $[D^{*}{\overline{D}}^{*}]$ channel.

We present a global embedding of the fiber inflation model in a perturbative large volume scenario (LVS) in which the inflationary potential is induced via a combination of string-loop corrections and higher derivative ${\mathrm{F}}^4$ effects. The minimal fiber inflation model developed in the standard LVS generically faces some strong bounds on the inflaton field range arising from the Kähler cone constraints, which subsequently creates a challenge for realizing the cosmological observables while consistently respecting the underlying supergravity approximations. The main attractive feature of this proposal is to naturally alleviate this issue by embedding fiber inflation in perturbative LVS.

We investigate the interior of the moduli space of four-dimensional $\mathcal{N}=1$ theories of gravity arising from compactifications of the $E_8\times E_8$ heterotic string on Calabi-Yau threefolds. By studying the threshold corrections to the coupling of the heterotic gauge groups, we infer the existence of a strong coupling singularity for one of the perturbative heterotic gauge groups, which effectively yields an additional finite distance boundary of the classical scalar field space. In heterotic M-theory, this boundary maps to a domain wall solution for which the gauge coupling and the warp factor on one of the Horava-Witten 9-branes diverge, thus highlighting the gravitational origin of the classical strong coupling singularity. The divergence of the warp factor is, however, regulated once nonperturbative effects are taken into account, as we demonstrate by studying the instanton corrections to the 5D BPS domain wall equations. This regularization implies that the classical strong coupling boundary of the scalar field 4D $\mathcal{N}=1$ heterotic M-theory is resolved, indicating that, at the quantum level, the field space can be extended beyond this classical boundary.

Convolutional neural networks (CNNs) have demonstrated potential for the real-time analysis of data from gravitational wave detector networks for the specific case of signals from coalescing compact-object binaries such as black-hole binaries. Unfortunately, CNNs presented to date have required a precise model of the target signal for training. Such CNNs are therefore not applicable to detecting generic gravitational wave transients from unknown sources, and may be unreliable for anticipated sources such as core-collapse supernovae and long gamma-ray bursts, where unknown physics or computational limitations prevent the development of robust, accurate signal models. We demonstrate for the first time a CNN analysis pipeline with the ability to detect generic signals—those without a precise model—with sensitivity across a wide parameter space and with useful significance. Our CNN has a novel structure that uses not only the network strain data but also the Pearson cross-correlation between detectors to distinguish correlated gravitational wave signals from uncorrelated noise transients. We demonstrate the efficacy of our CNN using data from the second LIGO-Virgo observing run. We show that it has sensitivity approaching that of the “gold-standard” unmodeled transient searches currently used by LIGO-Virgo, at extremely low (order of 1 s) latency and using only a fraction of the computing power required by existing searches, allowing our models the possibility of true real-time detection of gravitational wave transients associated with gamma-ray bursts, core-collapse supernovae, and other relativistic astrophysical phenomena.

The nature of gravitational singularities has been questioned by some recent research, challenging the notion that classical determinism breaks down at these points. By allowing for dynamic changes in the orientation of spatial hypersurfaces, Einstein’s equations can be uniquely extended across singularities in certain symmetry-reduced models. A key step in this work was to reformulate the dynamical equations in terms of physical degrees of freedom. The singular behavior, it turns out, is confined to the gauge or unphysical degrees of freedom, and the physical ones evolve smoothly through the singularity. This paper builds on these findings, extending them to a model of gravity coupled with Abelian gauge fields in a homogeneous but anisotropic universe. The study reveals that near the big bang, the dynamics of geometry and gauge fields can be reformulated in a way that preserves determinism, provided there is a change of orientation at the singularity. Intriguingly, the gauge fields are shown to maintain their orientation through the singularity, unlike the spatial hypersurfaces. This suggests that the predicted orientation change of spatial hypersurfaces has physical significance, potentially allowing an observer to determine which side of the big bang they occupy. These results are proved to also extend to non-Abelian gauge fields with only one spatial component.

Cosmic birefringence, the observed rotation of the polarization plane of the cosmic microwave background (CMB), serves as a compelling probe for parity-violating physics beyond the Standard Model. This study explores the potential of ultralight axion-like particle (ALP) dark matter to explain the observed cosmic birefringence in the CMB. We focus on the previously understudied mass range of ${10}^{-25}$ to ${10}^{-23}\mathrm{eV}$, where ALPs start to undergo nonlinear clustering in the late Universe. Our analysis incorporates recent cosmological constraints and considers the washout effect on CMB polarization. We find that for models with ALP masses ${10}^{-25}\mathrm{eV}\lesssim m_{\varphi }\lesssim {10}^{-23}\mathrm{eV}$ and birefringence arising from late ALP clustering, the upper limit on the ALP-photon coupling constant, imposed by the washout effect, is stringently lower than the coupling required to account for the observed static cosmic birefringence signal. This discrepancy persists regardless of the ALP fraction in dark matter. Furthermore, considering that ALPs with masses $m_{\varphi }\gtrsim {10}^{-23}\mathrm{eV}$ cannot explain static birefringence due to their rapid field oscillations, our results indicate that all ALP dark matter candidates capable of nonlinear clustering in the late Universe and thus contributing mainly to the rotation angle of polarized photons are incompatible with explaining the static cosmic birefringence signal observed in Planck and WMAP data.

Quintessence scalar fields are a natural candidate for evolving dark energy. Unlike the phenomenological $w_0{w}_a$ parameterization of the dark energy equation of state, they cannot accommodate the phantom regime of dark energy $w(z)<-1$, or crossings into the phantom regime. Recent baryon acoustic oscillation (BAO) measurements by the Dark Energy Spectroscopic Instrument (DESI) indicate a preference for evolving dark energy over a cosmological constant, ranging from $2.6\sigma -3.9\sigma$ when fitting to $w_0{w}_a$, and combining the DESI BAO measurements with other cosmological probes. In this work, we directly fit three simple scalar field models to the DESI BAO data, combined with cosmic microwave background anisotropy measurements and supernova datasets. We find the best fit model to include a 2–4% kinetic scalar field energy ${\mathrm{\Omega }}_{\mathrm{scf},\mathrm{k}}$, for a canonical scalar field with a quadratic or linear potential. However, only the DESY-Y5 supernova dataset combination shows a preference for quintessence over $\mathrm{\Lambda }$ cold dark matter (CDM) at the 95% confidence level. Fitting to the supernova datasets Pantheon, Pantheon+, DES-Y5, and Union3, we show that the mild tension ($n_{\sigma }<3.4$) under $\mathrm{\Lambda }\mathrm{CDM}$ emerges from a BAO preference for smaller values of fractional mass-energy density ${\mathrm{\Omega }}_m<0.29$, while all supernova datasets, except for Pantheon, prefer larger values, ${\mathrm{\Omega }}_m>0.3$. The tension under $\mathrm{\Lambda }\mathrm{CDM}$ remains noticeable ($n_{\sigma }<2.8$), when replacing two of the DESI BAO redshift bins with effective redshifts $z_{\mathrm{eff}}=0.51$, and $z_{\mathrm{eff}}=0.706$ with comparable BOSS DR 12 BAO measurements at $z_{\mathrm{eff}}=0.51$, and $z_{\mathrm{eff}}=0.61$. Canonical scalar fields as dark energy are successful in mitigating that tension.