Proton decay searches in the next generation of water Cherenkov detectors, such as Hyper-Kamiokande, are expected to probe the ${10}^{35}$-year lifetime regime where atmospheric neutrino backgrounds and systematic uncertainties begin to play an increasingly important role. In this study, we employ the gibuu framework and reevaluate the proton decay search sensitivity for the $\mathrm{p}\to {\mathrm{e}}^{+}{\pi }^0$ channel by incorporating a typical event reconstruction performance in water Cherenkov detectors. Using sophisticated models implemented in gibuu—most notably the mean-field potential and Boltzmann transport—which have been benchmarked against accelerator neutrino scattering data, in particular pion production, we find that the resulting proton decay signal detection efficiency and atmospheric neutrino background rate are comparable to those previously evaluated for the current and near future water Cherenkov experiments using ad hoc nuclear models. In addition to pion final-state interactions, we evaluate the impact of differences in the Fermi momentum distribution of nucleons in the nucleus, as a source of systematic uncertainty, on the signal detection efficiency and the expected background event rate. We find that the uncertainty associated with pion final-state interactions is moderate, whereas the choice of Fermi momentum distribution can significantly affect the estimated atmospheric neutrino background rate and constitutes the dominant contribution. Our study provides an independent and complementary characterization of nuclear effects on proton decay searches and helps to refine sensitivity estimates in the regime where systematic uncertainties become more relevant.

We study the discovery prospects for a doubly charged Higgs boson $H^{\pm \pm }$ in the 2-Higgs doublet model with type-II seesaw at future $e^{+}{e}^{-}$ colliders. Focusing on the three-body channels $e^{+}{e}^{-}\to H^{\pm \pm }{H}_1^{\mp }{H}_1^{\mp }$ and $e^{+}{e}^{-}\to H^{\pm \pm }{H}_1^{\mp }{W}^{\mp }$, we scan the model parameter space subject to theoretical consistency as well as current collider, flavor, and electroweak precision observables. We find that these $2\to 3$ production modes can exceed the conventional pair production rate $e^{+}{e}^{-}\to H^{++}{H}^{--}$, followed by $H^{\pm \pm }\to H_1^{\pm }{H}_1^{\pm }$ and $H_1^{\pm }{W}^{\pm }$ decays, over wide regions, particularly above the $H^{\pm \pm }\to H_1^{\pm }{H}_1^{\pm }$ and $H^{\pm \pm }\to H_1^{\pm }{W}^{\pm }$ thresholds, reaching cross sections up to $\mathcal{O}({10}^2)\mathrm{fb}$ for $\sqrt{s}=500–1500\mathrm{GeV}$. A detector-level analysis of the $4\ell +{\cancel{E}}_T$ signature, including dominant multiboson and top quark backgrounds, shows that discovery sensitivity is achievable for $\sqrt{s}=1000–1500\mathrm{GeV}$ with integrated luminosities in the few ${\mathrm{ab}}^{-1}$ range, even in the presence of realistic systematic uncertainties.

We investigate an extension of the left-right symmetric model featuring an additional non-Abelian $SU(2)$ gauge symmetry. The particle content is augmented by one generation of vectorlike leptons transforming under the fundamental representation of this new gauge group. We demonstrate that the neutral component of the vectorlike lepton multiplet naturally provides a viable and stable dark matter candidate. Stability is ensured by imposing a discrete parity symmetry that forbids mixing between the vectorlike leptons and the Standard Model leptons. As a consequence, the dark sector interacts with the visible sector exclusively through the vector portal (via s-channel processes) and the vectorlike lepton portal (via t-channel processes). In our analysis, we incorporate collider constraints on the mass of the first-generation extra charged gauge boson $W^{\prime \pm }$, while assuming that additional scalar states are decoupled from the relevant energy scale for simplicity. We identify the regions of parameter space consistent with the observed relic abundance, collider bounds on the charged partner $E^{\pm }$, current direct detection limits from the LUX-ZEPLIN experiment and indirect detection constraints from Fermi-Large Area Telescope. We find viable dark matter with a mass at the TeV scale. We show the complementarity of direct and indirect searches in probing the remaining parameter space of the model, in particular comparing the prospects of multiton direct detection experiments such as Xenon-Lux-Zeplin-Darwin and of the Cherenkov Telescope Array.

We present a secluded dark-matter (DM) framework based on an extra $U(1{)}_X$ gauge symmetry. The model contains a Dirac DM particle $\chi$, three heavy neutrinos $N_I$ with masses $M_{N,I}$, and a singlet scalar $R$ that mixes with the Standard Model Higgs doublet $\mathrm{\Phi }$ by an angle $\alpha$. A symmetry forbids the $\mathrm{\Phi }-R$ portal at tree level; the leading portal then arises at one loop from the same Yukawa structures that generate active neutrino masses $m_{\nu ,I}$, implying $\tan (2\alpha )\propto {\sum }_I{m}_{\nu ,I}{M}_{N,I}^2/(v_h{m}_H^2)$, where $v_h$ and $m_H$ are the Standard Model Higgs vacuum-expectation-value and mass. For heavy-neutrino masses in the multi-TeV range, this yields a naturally tiny mixing, $\tan (2\alpha )\sim 5\times {10}^{-11}{(M_N/10\mathrm{TeV})}^2$, which strongly suppresses DM signals in direct, indirect, and collider searches. For PeV-scale heavy neutrinos the loop-induced portal is enhanced and the DM-nucleon cross section can instead enter the reach of direct-detection experiments. The visible and dark sectors thermalize at temperatures of order a few times the mass of the lightest heavy neutrino, then subsequently decouple, and typically evolve with a slightly hotter dark bath. In the secluded regime, with $\tan (2\alpha )\ll 1$ and $m_{\chi }>m_{H_p}$, the relic density is set by $p$-wave annihilation $\chi \overline{\chi }\to H_p{H}_p$ (with $H_p$ the Higgs-like particle of the dark sector), and the dark-sector Yukawa couplings required to reproduce the observed abundance are $\mathcal{O}(0.1-1)$, as in the standard WIMP case. For heavy-neutrino masses $\gtrsim 10\mathrm{TeV}$, the mediator decays before nucleosynthesis without spoiling big bang nucleosynthesis observables, while the tiny portal suppresses present-day signals below current and near-future sensitivities. This links two long-standing puzzles—the absence of DM signals and the smallness of neutrino masses—within a predictive thermal framework.

The unsuppressed $CP$ violation in QCD is a problem in the standard model. If we have some mechanism to guarantee real determinants of the quark mass matrices, the vanishing physical vacuum angle $\overline{\theta }$ indicates the $CP$ invariance at the fundamental level. Thus, the small $\overline{\theta }$ is technically natural, since we have an enhanced $CP$ symmetry in the limit of the vanishing $\overline{\theta }=0$. In fact, it was proved that the vacuum angle is never renormalized up to the four-loop level once it is fixed at 0 value at some high energy scale. The purpose of this paper is to construct a model that guarantees the real determinants of the quark mass matrices assuming a noninvertible symmetry. In the present model, we have only one $CP$ violating phase and hence all observable phases such as phases in the Cabibbo-Kobayashi-Maskawa matrix, in the neutrino oscillation and in the leptogenesis are related. It should be remarkable that the correct sign of the baryon-number asymmetry in the present Universe is obtained and a narrow region for the $CP$ violating phase ${\delta }_{\mathit{CP}}\simeq 192°–197°$ is predicted.

Axionlike particles (ALPs) provide a well-motivated framework for physics beyond the Standard Model, coupling to gauge bosons through dimension-five operators protected by an approximate shift symmetry. At the LHC, such interactions lead to distinctive signatures in multiboson production, where the ALP appears as an off-shell mediator rather than a narrow resonance. In this work, we present the first global analysis of ALP-mediated multiboson processes, combining measurements of diphoton, $ZZ$, $W^{+}{W}^{-}$, dijet, and vector-boson-fusion (VBF) final states. On the theory side, motivated from a UV perspective, we assume that the ALP couples only to the gauge sector of the SM and classify the ALP-multiboson vertices that directly modify collider observables. Using Run-2 LHC measurements, we extract bounds on the Wilson coefficients $(c_{\tilde{G}},c_{\tilde{W}},c_{\tilde{B}})$ that parametrize gluonic and electroweak ALP interactions. Our results show that the dijet channel dominates the sensitivity to ALP couplings and determines the limits on $c_{\tilde{G}}$, while diboson and VBF processes provide complementary constraints on the electroweak couplings. We further assess the validity of the effective field theory expansion at the multi-TeV scales probed by the data. This global study provides the most comprehensive picture to date of ALP-gauge interactions from multiboson production at the LHC and highlights the opportunities for significant improvements with future high-luminosity measurements.

Massive scalar charges are ubiquitous in extensions to general relativity and the Standard Model in particle physics. We describe spectral methods which can accurately construct the spacetime of rotating black holes with dimensionless spin up to $a\le 0.8$ surrounded by massive scalar fields nonminimally coupled to spacetime curvature. We consider axi-dilaton, dynamical Chern-Simons, and scalar Gauss-Bonnet couplings, and obtain leading-order solutions for both the scalar field and the associated metric modifications. Our method accurately resolves massive scalar fields with Compton wavelengths as short as 5 times the black hole mass, achieving residual errors $\lesssim {10}^{-5}$, and yields the corresponding leading-order spacetime modifications with residual errors $\lesssim {10}^{-3}$. Using the constructed spacetimes, we computes the leading-order shifts in the surface gravity and the angular velocity of the event horizon, important information for computing the quasinormal modes. These results pave the way to incorporate massive scalar charges into electromagnetic observations and gravitational-wave detections of black holes, potentially enabling new probes of fundamental scalar degrees of freedom.

We study the color correlation between two static quarks in 3Q ($QQQ$) and 4Q ($QQ\overline{Q}\overline{Q}$) multiquark systems at $T=0$ based on the reduced two-body density matrices $\rho$ in color space. We perform quenched lattice QCD calculations with the Coulomb gauge adopting the standard Wilson gauge action, and the spatial volume is $L^3=32^3$ at $\beta =5.8$, which corresponds to the lattice spacing $a=0.14\mathrm{fm}$ and the system volume $L^3={4.5}^3{\mathrm{fm}}^3$. We evaluate the two-body color density matrix $\rho$ of static quarks and investigate the dependence of color correlations on the quarks’ spatial configuration. As a result, we find that the color correlations depend on the minimal path length along a flux tube which connects two quarks under consideration. The color correlation between quarks quenches because of color leak into the gluon field (flux tube) and the color configuration of quarks finally approaches the random one in the large distance limit. We also find a “universality” in the flux-tube path length dependence of the color correlations for 2Q, 3Q, and 4Q ground-state systems. Our results show that the color correlations of end-point quarks can be a clue to clarify the internal structures of hadrons, including exotic (multiquark) hadrons.

For the first time, we incorporate the cascade-type topology $D^0\to {\pi }^{-}{a}_1^{+}(1260)(\to {\pi }^{+}{\rho }^0(\to {\ell }^{+}{\ell }^{-}))$ to describe the recently measured rare charm-meson decays. We find that it comprises one of the largest contributions to the decay rate and obtain an unprecedented agreement of the Standard Model prediction with the available LHCb data while also aptly describing four-body nonleptonic transitions. In the presence of this cascade component, we predict that some angular observables acquire nonzero values, further stressing its phenomenological relevance and its potential for constraining new physics.

Assuming $X(6900)$ is a tetraquark state, the decay width of $X(6900)\to 2J/\psi$ is calculated in a covariant quark model, with the diquark-antidiquark $[cc][\overline{c}\overline{c}]$ picture. Two possible structures, vector-vector and axial-vector–axial-vector coupling, are investigated. The result indicates that the axial-vector–axial-vector coupling is consistent with the experiments. Additionally, as another application of the covariant quark model, the decay width of $X(6900)\to 2{\eta }_c$ is predicted to be 66–88 keV.

Inspired by the recent discovery of a pseudoscalar enhancement structure near the $t\overline{t}$ threshold reported by the CMS and ATLAS Collaborations, this work investigates the mass spectra of single topped hadrons—including both topped mesons and topped baryons—based on a relativistic potential model. Using the same parameters obtained from the fit to mesons and baryons, we provide predictions for the mass spectra of ground and low-lying orbitally excited single topped mesons and baryons. In addition, we point out that the precise measurement of the $t\overline{t}$ mass could test the limitation of the potential model. Given the extremely large mass of the topped quark, we discuss spectroscopic properties of topped hadrons in the approximation of an ideal heavy-quark limit.

We investigate the spectral functions of neutral and charged mesons in a hot dense medium under a external magnetic field using the two-flavor quark-meson model within the functional renormalization group framework. Our results show that the spectral functions of $\sigma$ and ${\pi }_0$ mesons develop new structures due to decay channels into quarks occupying different Landau levels. By consistently incorporating the momentum relations at vertices for charged particles in a magnetic field, we further show that the ${\pi }_{+}$ spectral function develops a multipeak structure at finite temperatures, resulting from the various annihilation and decay channels available to ${\pi }_{+}$ in the magnetic environment. This multipeak structure is further enhanced in a finite-density medium, causing the ${\pi }_{+}$ meson to become a broad resonance at lower temperatures and densities compared to neutral mesons. Such a multipeak pattern is expected to be universal for charged mesons under magnetic fields and carries significant implications for understanding transport properties in magnetized strongly interacting fluids.

A search for dark matter particles produced in association with a Higgs boson decaying to a bottom quark-antiquark pair in proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$ is presented. The data, collected with the CMS detector at the LHC, correspond to an integrated luminosity of $101{\mathrm{fb}}^{-1}$. The analysis is performed in exclusive categories targeting both Lorentz-boosted (merged) and resolved $b$ jet pair topologies, covering a wide range of Higgs boson transverse momentum. A statistical combination is made with a previous search using data collected in 2016 and corresponding to an integrated luminosity of $35.9{\mathrm{fb}}^{-1}$. The observed data agree with the standard model background predictions. Constraints are placed on models predicting new particles or interactions, such as those in the simplified frameworks of baryonic-$Z^{\prime }$ and $2\mathrm{HDM}+a$, where the latter is a type-II two-Higgs-doublet model featuring a heavy pseudoscalar with an additional light pseudoscalar. Upper limits at 95% confidence level are set on the production cross section for these models. For the baryonic-$Z^{\prime }$ model, $Z^{\prime }$ boson masses below 2.25 TeV are excluded for a dark matter particle candidate mass of 1 GeV. In the $2\mathrm{HDM}+a$ model, heavy pseudoscalar masses between 850 and 1300 GeV are excluded for a light pseudoscalar mass of 350 GeV.

The water-based liquid scintillator (WbLS) enables hybrid detection by combining scintillation and Cherenkov signals, providing superior event reconstruction capabilities compared to conventional neutrino detectors. We measured the light yield of Gd-compatible WbLS at varying concentrations from 0.35% to 1% by mass, using cosmic-ray muons in a 1-ton scale detector at Brookhaven National Laboratory. The light yield is measured as $(69.2\pm 6.9)\mathrm{ph}/\mathrm{MeV}$ at 0.35% concentration, which increased to $(87.3\pm 8.7)\mathrm{ph}/\mathrm{MeV}$ at 1%. These results establish a quantitative basis for optimizing future WbLS-based detectors in neutrino physics.

The Higgs boson (H) decay width is determined from the ratio of off- and on-shell production of $H\to WW\to e\nu \mu \nu$ using proton–proton collision data corresponding to an integrated luminosity of $138{\mathrm{fb}}^{-1}$ collected at $\sqrt{s}=13\mathrm{TeV}$ by the CMS experiment at the Large Hadron Collider. The off-shell signal strength is measured as ${\mu }_{\mathrm{off}\text{−}\mathrm{shell}}={1.2}_{-0.7}^{+0.8}$. The Higgs boson total decay width is ${\mathrm{\Gamma }}_H={3.9}_{-2.2}^{+2.7}\mathrm{MeV}$, in agreement with the standard model prediction. The uncertainty in this result represents a factor of 3 improvement over the previous CMS result in this decay channel.

Motivated by the observations of $T_{c\overline{s}0}(2900{)}^0$ and $T_{c\overline{s}0}(2900{)}^{++}$, we propose to search for ${T_{c\overline{s}0}(2900)}^0$ in the cleaner process $B^{-}\to K^{-}{D}^0{K}^0$. In the $D^{*}{K}^{*}$ molecular picture, our estimates suggest that $T_{c\overline{s}0}(2900{)}^0$ should contribute significantly to the $D^0{K}^0$ invariant mass distribution in $B^{-}\to K^{-}{D}^0{K}^0$, as reported by the Belle II Collaboration. The corresponding fit fraction is estimated to be $(9.72\pm 3.92)\%$ or $(7.09\pm 5.88)\%$ in different fitting schemes. Further precise measurements of this process at Belle II and LHCb could be helpful for clarifying the nature of $T_{c\overline{s}0}(2900)$.

Coherent elastic neutrino-nucleus scattering ($\mathrm{CE}\nu \mathrm{NS}$) provides a pathway for reactor monitoring via compact detectors, benefiting from its enhanced cross section relative to inverse beta decay. We present a benchmark estimate of the sensitivity of $\mathrm{CE}\nu \mathrm{NS}$-based detectors to changes in the nuclear recoil spectrum caused by variations in reactor fuel composition, including ${}^{239}\mathrm{Pu}$ diversion. Incorporating spectral-shape information alongside rate measurements reduces the exposure required to detect a given amount of diverted plutonium compared to rate-only approaches. Across reactors of varying thermal power and fuel enrichment, low-power enriched-fuel reactors offer the most favorable detection conditions. Together, these results delineate how rate and spectral information in the $\mathrm{CE}\nu \mathrm{NS}$ interaction channel encode its fundamental sensitivity to plutonium diversion across reactor configurations.

From the AdS/CFT dictionary, we derive a bulk dual of the work distribution defined by the two-point measurement on the boundary, yielding a bulk formulation of the Tasaki-Crooks fluctuation theorem. We argue that this does not merely supply a holographic prescription for the work distribution; it encodes the mean energy change and fluctuations of bulk real-time dynamics associated with the two-point measurement.