Standard-Model (SM) hadronic parton showers initiated by secondary cosmic-ray production or dark matter (DM) annihilations robustly predict very low antinuclei yields and a strong additional suppression for heavier antinuclei. We show that an important exception can arise if DM annihilates into a confining dark sector that produces soft unclustered energy patterns (SUEPs). The hallmark of SUEPs is the emission of very large multiplicities of soft dark mesons (pi D), which can overcome the usual phase-space suppression of antinuclei formation in parton showers, provided that the dark mesons decay promptly into SM quarks, i.e., within a SM hadronization length. We study several benchmark realizations and find that for DM masses mDM O(10 TeV), dark meson masses m pi D 400 GeV, pi D dominantly decaying to tt & strns;, and a SUEP temperature TSUEP <^> 0.1m pi D, DM annihilation into SUEPs can yield tens of antideuterons and a few antihelium-3 events at AMS - 02 at kinetic energies of O(GeV/n) and a few antideuterons and antihelium-3 events in GAPS at energies below 0.5 GeV/n. A future confirmation of an antinuclei signal by the AMS - 02 or GAPS experiments could provide hints for hidden confining dynamics and would significantly constrain the relevant SUEP parameters.
We compute the electromagnetic form factors of the proton and neutron using lattice QCD. We employ Nf = 2 + 1 + 1 twisted mass clover-improved fermions with quark masses tuned to their physical values. Three ensembles with lattice spacings of a = 0.080 fm, 0.068 fm, and 0.057 fm and approximately the same physical volume allow us to obtain the continuum limit directly at the physical pion mass. For each ensemble, we use several values of the sink-source time separation, ranging from 0.5 to 1.5 fm, to allow for a thorough analysis of excited-state effects via multistate fits. The disconnected contributions are also analyzed using high statistics combined with techniques to mitigate stochastic noise in the estimation of the fermion loop. These techniques include low-mode deflation, dilution in the color and spin components, and hierarchical probing. We study the momentum-transfer dependence of the form factors using the z-expansion and dipole Ans & auml;tze, thereby enabling the extraction of the electric and magnetic radii and the magnetic moments, as well as the Zemach and Friar radii in the continuum limit. Results for the proton and neutron electric and magnetic mean square radii are p ffiffiffiffiffiffiffiffiffiffiffi p ffiffiffiffiffiffiffiffiffiffiffi (r2 E)n = -0.147(48) fm2, (r2 M)p = 0.870(53)(15) fm, and (r2M)n = 0.913(67)(19) fm, and for the proton and neutron magnetic moments, mu p = 2.849(92)(52) and mu n= -1.819(76)(29), respectively. In all cases, the first error is statistical, and the second is systematic, where the latter includes an estimate of the error from the fits to the momentum dependence of the form factors and from the continuum extrapolation.
Using (2.712 +/- 0.014) x 10(9) psi(3686) events collected with the BESIII detector at the BEPCII collider, we report an evidence of Xi(0) transverse polarization with a significance of 4.4 sigma, a precise measurement of the branching fraction and the ratios between the S-wave and D-wave contributions of psi(3686) -> Xi(0)(Xi) over bar (0). The weak decay parameters (phi(Xi 0/(Xi) over bar)0, alpha(Xi 0/(Xi) over bar0)) and the angular distribution (alpha(psi)) are also measured with higher precision compared to the previous measurements. Furthermore, two the CP observables are also determined to be A(CP)(Xi 0) = -0.014 +/- 0.030 +/- 0.010 and Delta phi(Xi 0)(CP) = 0.000 +/- 0.028 +/- 0.003 rad, which are still consistent with CP conservation at 1 sigma level under the current statistics.
The photon is arguably the most universally important particle across all fields of physics. Despite its status as a fundamental particle, at high energies the photon can be seen as a hadronic source of partons. The partonic content of the photon is very poorly constrained compared to that of the proton, with uncertainties in the photon parton distribution functions typically 1 or 2 orders of magnitude larger than their proton counterparts, despite the fact that its source, the gamma -* qq & strns; splitting, is perturbatively calculable. The high luminosity, excellent particle identification, and far-backward electron tagging capabilities of the Electron-Ion Collider (EIC) make it an ideal environment for studying photon parton distribution functions. Similar to the p + p or pi + p systems, photoproduction at the EIC can be thought of as two parton distributions colliding. One of the most powerful processes in such collisions is production of lepton pairs, i.e. h + p -* l+l- + X, known as the Drell-Yan process. This process has the ability to access for the first time the transverse-momentum-dependent parton distributions of the photon. The transversely polarized proton beam of the EIC additionally provides a possible means of accessing the transversity distribution of the proton without relying on fragmentation functions.
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 6 and ,r0 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 ,r & thorn; spectral function develops a multipeak structure at finite temperatures, resulting from the various annihilation and decay channels available to ,r & thorn; in the magnetic environment. This multipeak structure is further enhanced in a finite-density medium, causing the ,r & thorn;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.
Using a 10.9 fb(-1) data sample collected by the BESIII detector at center-of-mass energies from 4.16 to 4.34 GeV, we search for the charmless decays X(3872) -> (KSK +/-)-K-0 pi(-/+) and K*(892)K ($) over bar, where the X(3872) is produced via the radiative process e(+)e(-) -> gamma X(3872). No significant signal is observed. We set upper limits on the relative branching fractions B[X(3872) -> (KSK +/-)-K-0 pi(-/+)]/B[X(3872) -> pi(+)pi(-)J/psi] < 0.07 and B[X(3872) -> K*(892)<(K)over bar>]/B[X(3872) -> pi(+)pi(-)J/psi] < 0.10 at the 90% confidence level. Additionally, upper limits on the product of the cross section sigma[e(+)e(-) -> gamma X(3872)] and the branching fractions B[X(3872) -> (KSK +/-)-K-0 pi(-/+)] and B[X(3872) -> K*(892)(K) over bar] are reported at each energy point. In all cases, K*(892)(K) over bar refers to the sum of the modes K*(892)K-+(-) thorn c.c. and K*(892)(0)(K) over bar (0) + c.c., where c.c. denotes the corresponding charge-conjugate modes.
At hadron colliders, the net transverse momentum of particles that do not interact with the detector (missing transverse momentum, (p) over right arrow sub(miss) over T) is a crucial observable in many analyses. In the standard model, (p) over right arrow sub(miss) over T) originates from neutrinos. Many beyond-the-standard-model particles, such as dark matter candidates, are also expected to leave the experimental apparatus undetected. This paper presents a novel deep neural network based. (p) over right arrow sub(miss) over T) estimator, DeepMET, developed by the CMS Collaboration at the LHC. The DeepMET algorithm produces a weight for each reconstructed particle based on its properties. The estimator is based on the negative vector sum of the weighted transverse momenta of all reconstructed particles in an event. Compared with other estimators currently employed by CMS, DeepMET improves the (p) over right arrow sub(miss) over T) resolution by 10%-30%, shows improvement for a wide range of final states, is easier to train, and is more resilient against the effects of additional proton-proton interactions accompanying the collision of interest.
The Cabibbo-favored decay A+ c-* nK & strns;0tc+ offers a unique window to explore unresolved puzzles in the low-energy baryon spectroscopy and the isospin dynamics of the K & strns;N system. Recent experimental results present a, for now, contradiction: LHCb and Belle analyses of A+ c-* pK-tc+suggest the pK-(I = 0) component dominates, while the Beijing Spectrometer III (BESIII) hints at significant contributions from both isospin 0 and 1 in the nK & strns;0 system of A+ c-* nK0Stc+. Furthermore, the measured branching fraction of A+ c-* nK0Stc+exceeds SU(3) symmetry predictions by a factor of 3-4, signaling strong contributions from low-lying resonances. In this work, we provide a theoretical analysis of A & thorn;c-* nK & strns;0tc+ within the coupled-channel chiral unitary approach, where the N(1535) and A(1670) can be dynamically generated. Our calculations show a narrow peak from N(1535) in the tc+n invariant mass spectrum and a distinct dip from A(1670) in the K & strns;0n spectrum. The dip structure is qualitatively consistent with the A(1670) manifestation in K & strns;N-* K & strns;N scattering, supporting its molecular interpretation. This study not only connects the experimental observations but also highlights A+ c-* nK & strns;0tc+ as a crucial process to disentangle the nature of N(1535) and A(1670). Future precise measurements of this decay channel by the BESIII, Belle II, LHCb, and the proposed Super Tau-Charm Facility are strongly encouraged.
Disturbances in gravitational wave (GW) observational data are often caused by nonstationary noise in the detector itself, such as backscattering of laser stray light into the signal field. Unlike GW signals, nonstationary noise can appear in both the GW-signal quadrature and the orthogonal quadrature, which is usually not measured. Simultaneous sensing of this orthogonal quadrature provides a witness channel that can be used to reconstruct the disturbance in the signal quadrature enabling subtraction of nonstationary noise. Here, we present the concept of quadrature witness that is compatible with frequency-dependent squeezing, which is already used to simultaneously reduce photon shot noise and photon radiation-pressure noise. We demonstrate that implementing this approach in a GW detector could reduce noise caused by loud backscatter events, thereby improving the overall sensitivity and robustness of GW observatories.
We investigate the effective potential and the string tension for the spatial Wilson loop in hot dense quark-gluon plasma with two types of anisotropy, i.e., external magnetic field and spatial anisotropy, employing a holographic approach for the heavy quark model. In this approach, the string is extended in the fifth, holographic direction and has a turning point either on a dynamical wall (DW) configuration or on the horizon configuration in the fifth direction. We obtain the magnetic catalysis behavior for a phase transition between DW and horizon configuration of the string. The structure of the phase diagram does not depend on the boundary conditions choice for the dilaton field. Inclusion of the external magnetic field and spatial anisotropy enhance the string tension in the horizon configuration, namely drag force. For the spatially isotropic case nu = 1 at different magnetic field values, the string tension is proportional to T2 and is qualitatively consistent with lattice results. However, for the anisotropic case, nu = 4.5, it deviates from the quadratic term.
In this work, we study the radiative decays of the Ec, c, and 1 ccharmed baryons, which belong to the flavor sextet (6F), within the constituent quark model formalism. The electromagnetic transitions are calculated from the ground and P-wave states to ground states, as well as from the second shell states to both the ground and P-wave final states. These decays play a crucial role in confirming the existence of certain resonances when strong decays are not allowed. Moreover, electromagnetic decay widths are particularly useful for identifying resonances when states have the same mass and total decay width. A relevant case is the 1 c(3327) state, whose branching ratios between the strong decay channels are comparable; thus, the radiative decay widths may help assign this state. We also make the assignment of the recently discovered c(2923)+ baryon, which is consistent with being the isospin partner of the E c(2923)0. mixed states, and rho-mode radially excited states in the charm sector. Throughout our calculations, we account for uncertainties arising from both experimental and model-dependent errors.
In the Cachazo-He-Yuan (CHY) representation, many tree-level scattering amplitudes are written as integrals localized by the scattering equations, where the CHY integrand encodes the theory and must reproduce the physical factorization pattern of Mandelstam singularities. The inverse CHY problem therefore asks for a rational integrand whose physical poles match a prescribed set of factorization channels, a task that becomes rapidly combinatorial at higher multiplicity. We present an algorithmic approach that makes the subset structure of pole data explicit by assigning each particle subset A a generalized pole degree K(A), realized as a signed internal-edge count in a colored integrand graph. Additivity under integrand multiplication and an elementary face recursion on the subset lattice imply that all higher-channel K(A) are linear functions of the two-particle integers {K(si1)}, so the inverse step becomes a mixed-integer linear feasibility problem. The same subset lattice provides a fixed computation graph for exact constraint satisfaction: pole requirements and recursion identities are treated as hard constraints, updates are restricted to those that preserve feasibility, and whenever a proposed change would enter a fixed node its constraint residual is rerouted and redistributed through unfixed degrees of freedom so that all constraints remain satisfied throughout. After a factorial rescaling, every local propagation update is purely integral, keeping the entire procedure exact in integer arithmetic and avoiding a posteriori reconstruction from numerical evaluations. Since physical tree-level amplitudes must contain only simple factorization poles as dictated by unitarity and locality, we further organize generalized integrands by an n-regular grading under multiplication, where degree-zero factors act as M & ouml;bius-invariant insertions admitting a decomposition into products of four-point cross ratios, which guides efficient higher-order pole reduction. We illustrate the construction at six and eight points, including pole selection and higher-order pole reduction.
We present a formulation of the spherically decomposed Green's function for a Schwarzschild black hole, based on a decomposition into two components, G & thorn; and G-, based on their large-frequency behavior. While similar decompositions have been considered previously, here we systematically apply it to Schwarzschild spacetime and analyze its implications for the analytic structure of the Green's function in the complex-frequency plane. We show that both G & thorn; and G- possess branch cuts along the imaginary axis, which give rise to the direct part and the late-time tail, while the poles of G & thorn; correspond to the quasinormal mode spectrum. This allows us to identify a branch-cut direct part, a quasinormal-mode contribution, and a late-time tail through contours adapted to different causal spacetime regions. This is in sharp contrast to Leaver's original formulation, where the prompt response is tied to a technically difficult large-arc contribution. We validate our decomposition with independent time-domain Regge-Wheeler simulations finding excellent agreement. Our results provide a practical and physically transparent framework for disentangling the distinct pieces of the Schwarzschild response, and offer a natural starting point for extensions to Kerr perturbations and nonlinear ringdown physics.
We propose a novel self-interacting dark matter (SIDM) model mediated by a light leptophilic scalar boson to solve long-standing small-scale structure problems within the Lambda cold dark matter (Lambda CDM) framework. Small-scale anomalies such as the core-cusp problem challenge the traditional CDM framework. Therefore, we introduce a scalar-mediated SIDM model as an alternative to CDM that naturally addresses these problems. It also exhibits p-wave-suppressed annihilation and avoids constraints from the cosmic microwave background. In our model, we assume pseudo-Dirac dark matter with a small mass splitting of order 102 eV to ensure kinematic scattering suppression in satellites. We also introduce a dimension-five transition magnetic dipole operator to satisfy big bang nucleosynthesis requirements. It allows the decay x2 -* x1y, so the excited-state abundance is primarily depleted by exothermic selfinteractions (x2x2 -* x1x1) in the early Universe. This ensures that the excited-state population is negligible for structure formation at the dipole scale Lambda eff greater than or similar to 107 GeV. The model is made inelastic by a dark discrete Z2 symmetry that prevents tree-level elastic scattering. Treating the scattering dynamics nonperturbatively in a Schr & ouml;dinger framework yields a relatively small residual resonant benchmark window (mx 40 GeV, Delta m 100 eV, m, 20 MeV). In such a system, the kinematic threshold minimizes interactions in ultrafaint Milky Way satellites, while resonant effects produce large cross sections, 6/m O(10) cm2/g, in field dwarf galaxies. Current direct-detection prospects are weak, and the leptophilic scalar mediator keeps the model away from existing nuclear recoil constraints. However, the low-threshold dipole operator provides a potential discovery channel for future xenon-based experiments.
Nonlinearly scalarized black holes are investigated in Einstein-scalar-Gauss-Bonnet theory with polynomial coupling functions zeta & eth;phi & THORN; satisfying zeta 00 & eth;0 & THORN; 1/4 0, where zeta 0 & eth;phi & THORN; 1/4 0 features besides phi 1/4 0 solutions with constant phi s not equal 0. We determine the threshold amplitudes for Gaussian pulses, above which Schwarzschild black holes (SBHs) transition to scalarized black holes for two coupling functions; zeta & eth;phi & THORN; 1/4 alpha phi 4 - beta phi 8 and zeta & eth;phi & THORN; 1/4 alpha phi 4 - beta phi 6. In contrast, for the quartic coupling function zeta & eth;phi & THORN; 1/4 alpha phi 4 SBHs are stable. Treating zeta & eth;phi & THORN;R2GB as an effective potential Veff provides an explanation for the "plateau" and the divergence observed in the time evolution. We then construct the branches of nonlinearly scalarized black holes in the probe limit and with backreaction. While the pattern of the solution branches in the probe limit exhibits universal features, the presence of backreaction reveals a distinct dependence on the coupling strength beta.
In a previous paper [Flores-Baez et al., Phys. Rev. D 76, 096010 (2007)] we have calculated the radiative corrections to rho -> pi pi decays, aiming to estimate the width difference between charged and neutral rho mesons. There, we have used the scalar quantum electrodynamics approximation and considered the convection terms to keep the loop contributions finite in the case of charged rho meson decays. Here we compute the radiative corrections by considering the electromagnetic structure of charged mesons and we also include the full Lorentz structure of the electromagnetic vertices. We reevaluate the width difference of rho(+/-) - rho(0) vector mesons and calculate the structure-dependent contributions to final state radiation terms in the e(+) e(-) -> pi(+)pi(-) cross section. Both effects are important inputs for evaluating the isospin breaking corrections in the dominant hadronic vacuum polarization contributions to the muon g - 2 when using tau lepton data.
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 NI with masses M-N;I, and a singlet scalar R that mixes with the Standard Model Higgs doublet Phi by an angle alpha. A symmetry forbids the 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)proportional to Sigma(I)m nu;M-I(N;I)2=(v(h)m(2)H), 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) 5 & times; 10(-11)(M-N=10 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) << 1 and m chi > m(Hp,) the relic density is set by p-wave annihilation chi chi & strns;-> HpHp (with H(p )the Higgs-like particle of the dark sector), and the dark-sector Yukawa couplings required to reproduce the observed abundance are O(0.1-1), as in the standard WIMP case. For heavy-neutrino masses greater than or similar to 10 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.
A time- and flavor-integrated amplitude analysis of B-0 and B-s(0) decays to the (K+ pi(-)) (K-pi(+)) final state in the K*(892)(0) (K) over bar*(892)(0) region is presented, using pp collision data recorded with the LHCb detector in 2011-2018, corresponding to an integrated luminosity of 9 fb(-1). The branching fractions of the B-0 and B-s(0) decays are measured relative to the B-0 -> D-pi(+) and B-s(0) up arrow D-s(-) pi(+) modes, respectively. The corresponding longitudinal polarization fractions are found to be f(L)(d) = 0.600 +/- 0.022 +/- 0.017 and f(L)(s) = 0.159 +/- 0.010 +/- 0.007, where the uncertainties are statistical and systematic, respectively. The theory-motivated ratio of the squared B-s(0) to B-0 longitudinally polarized decay amplitudes is found to be L-K*0 (K) over bar *0 = 4.92 +/- 0.55 +/- 0.48 +/- 0.02 +/- 0.10, where the uncertainties are statistical, systematic, due to uncertainty of external mass and lifetime measurements, and due to knowledge of the fragmentation fraction ratio, respectively. This confirms the previously reported tension between experimental determinations and theoretical predictions of longitudinal polarization in B -> VV decays at the level of 4.4 standard deviations.
Coherent elastic neutrino-nucleus scattering (CEvNS) 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 CEvNS-based detectors to changes in the nuclear recoil spectrum caused by variations in reactor fuel composition, including 239Pu 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 CEvNS interaction channel encode its fundamental sensitivity to plutonium diversion across reactor configurations.
Using e(+)e(-) collision data collected with the BESIII detector corresponding to an integrated luminosity of 44.2 fb(-1), we measure the Born cross sections for the process e(+)e(-) -> Xi(1530)(0)(Xi) over bar (0) + c.c. at 48 centerof-mass energies between 3.51 and 4.95 GeV. The potential signal from non-D (D) over bar decays for psi(3770), i.e., psi(3770) -> Xi(1530)(0)(Xi) over bar (0) + c.c., is investigated by fitting the dressed cross section, no obvious signal is found. The upper limit of B(psi(3770) -> Xi(1530)(0)(Xi) over bar (0)) at 90% confidence level is given.
