A J-resolved spectroscopy that depends on homonuclear scalar coupling in the strong-coupling regime and heteronuclear coupling in the weak regime expands complex peak patterns to a second axis. Hyperpolarization by Signal Amplification by Reversible Exchange (SABRE) enables the spectroscopy at a low magnetic field of 0.82 mT. Overlapping peaks of molecules such as 3-fluoropyridine and 3,5-difluoropyridine are resolved. Density matrix simulations of the 1H and 19F spins indicate a strong dependence on the signs and values of the J-coupling constants, including the homonuclear couplings that are not directly observable. The best matching peak positions and intensities predict coupling constants, including couplings between chemically equivalent nuclear spins, ranging in magnitude from 0.4 to 9.0 Hz for the two molecules. Simulations of other spin systems show unique patterns for molecules containing 1H and 19F or 13C. The dependence of the J-resolved peak patterns on all coupling constants in a spin system presents a new modality for portable and inexpensive identification of molecules.

Nuclear magnetic resonance (NMR)-based 13C tracing is widely used in medicine, metabolomics, and environmental research. Here, we introduce a 2D 1H-1H (12C/13C) "in-phase/opposite-phase" (IP/OP) TOCSY experiment that uniquely generates 2D subspectra discriminating 13C-13C, 12C-13C, and 12C-12C connectivity. The sequence was demonstrated first on a standard mixture of 50/50 13C-phenylalanine and 1-13C-glucose, followed by an in vivo ethanol fermentation using brewer's yeast (Saccharomyces cerevisiae) with 1-13C-glucose. Finally, incorporation of 13C in marine copepods (Tigriopus californicus) was monitored ex vivo. Copepods were analyzed at natural abundance and again on 7 days of feeding >98% 13C-enriched green algae. The sequence successfully identified three carbon pools: intact fragments or molecules from the 13C diet (13C-13C), intact fragments from pre-existing biomass (12C-12C), and new bond formation between 12C and 13C molecules during metabolite turnover (12C-13C). Molecules involved in osmotic regulation, alanine, proline, glycine, choline, betaine, and TMAO, were particularly abundant in the 12C-13C pool, suggesting rapid turnover by combining 13C food with existing 12C biomass. This was supported by a quantitative 1D 1H-(12C/13C) IP/OP experiment, measuring average enrichment of the six osmolytes at 22.8 ± 0.1% 13C on day 7. A complementary "singlet-only" experiment quantified glycine at 27.4 ± 0.2% 13C and betaine at 3.7 ± 0.4% 13C, enabling detection of molecules without scalar couplings. In summary, the 2D 1H-1H IP/OP TOCSY simultaneously identified pre-existing and newly synthesized molecules, while 1D experiments provide quantitative support, offering a sensitive framework to study carbon dynamics, preservation, and transformation in complex in vivo and ex vivo processes.

Grand unified origin of enhanced scalar couplings: Connecting radiatively broken electroweak symmetry to SO(10) dynamics

Isoaspartate forms spontaneously from Asn deamidation or Asp isomerization, which can plague protein purification and storage processes. Indeed, it often comes with deleterious consequences, from a loss of function to a gain of toxic properties. IsoAsp detection is not straightforward, notably because it causes weak mass shifts, i.e., +1 or 0 from the native Asn or Asp, respectively. NMR spectroscopy might help in nontargeted detection of isoAsp, but information on isoAsp NMR fingerprint and sensitive detection methods were missing. Here, we report the NMR characterization of isoAsp in ten model, random coil hexapeptides, and release reference chemical shifts and scalar couplings of backbone nuclei from (i-1)-(i)-(i+1) residues (from 283 to 310 K). We show how isoAsp chemical shifts evolve with pH (from 2 to 8) and urea concentration (from 0 to 8 M). This led us to draw methods to identify isoAsp in 13C/15N-enriched and in natural abundance polypeptides. In the latter case, we use notably trypsinization, protein denaturation, and 1H-only NMR, enabling the detection of 10 nmol of isoAsp-containing protein in 1 h. We exemplify this approach on therapeutic products like insulin or the monoclonal antibody trastuzumab.

The need to achieve high quality heteronuclear decoupling is a topic that has been given due attention for a long time now to optimize such aspects as complete decoupling with suppression of decoupling sidebands, bandwidth, and required power. However, one aspect that has been neglected, and there appears to be only one report that specifically addresses the issue, concerns the problem of very large coupling constants, for example, when proton is directly bound to phosphorous. For instance, in diethyl phosphonate {HP(=O)(OCH2CH3)2},1 J H,P is 693 Hz and this large coupling results in decoupling sidebands and artifacts when employing standard composite-pulse decoupling schemes such as WALTZ or GARP; even adiabatic-pulse and MPF decoupling fail to provide complete suppression of the decoupling sidebands and artifacts. Herein it is demonstrated that superior 1H decoupling when acquiring a 31P NMR spectrum is accomplished by spin locking the 1H magnetization using adiabatic pulses. Significantly, this can be performed using a two-channel instrument as opposed to the previous methodology which ostensibly required a three-channel instrument.

A bstract Effective field theories featuring light scalar fields play a pivotal role in addressing fundamental questions in (astro)particle physics and cosmology. However, such theories often confront hierarchy problems in the absence of a symmetry. Self-completion via classicalization offers a non-Wilsonian approach to ultraviolet (UV) completion, wherein new scalar self-interactions involving derivatives give rise to Vainshtein-like screening around energy-momentum sources. Rather than introducing new UV degrees of freedom to restore unitarity at high energies, these theories reshuffle their infrared (IR) degrees of freedom by generating extended semi-classical objects — referred to as classicalons — which decay into a multitude of soft particles. This mechanism incorporates non-localizable fields, thereby realizing a form of UV/IR mixing that is analogous to the dynamics of black holes in gravitational theories. In this article, having reviewed the fundamental principles of classicalization with a simple k-essence model, we then argue the necessity of maintaining a little hierarchy between the scalar mass and the scale of the first new resonances, thereby illustrating the impact of UV/IR mixing on hierarchy problems. Additionally, we investigate the effects of a scalar potential and couplings to fermions on the Vainshtein screening mechanism. We discuss that a chameleon-like screening mechanism must accompany the Vainshtein screening to preserve the integrity of classicalon solutions.

Scalar fields in the early Universe are mostly discussed in two limits: either in equilibrium or completely decoupled.In this work we discuss scenarios where there are scalar fields that are not in equilibrium, but for which the coupling to thermal bath leads to interesting non-trivial dynamics.For example, in theories where scalar fields control the effective couplings of the theory, such out-of-equilibrium behavior can lead to cases where the couplings vary during cosmological evolution.We systematically examine the generic features governing the evolution of these couplings, and as an application we highlight a novel effect where the scalar quartic coupling of an Abelian Higgs model is modified, leading to stronger cosmological phase transitions than would be obtained for static non-evolving quartics.

We propose the nuclear interferometer - a single-photon interferometry experiment based upon the thorium-229 nuclear clock transition - as a novel detector for ultra-light dark matter. Thanks to the enhanced sensitivity of this transition to the variation of fundamental constants, we find that possible realisations of such an experiment deploying either single ions or clouds of atoms have the potential to complement advanced very-long-baseline terrestrial clock atom interferometers in the search for ultra-light dark matter with scalar couplings to photons in the future. Nuclear interferometry may also offer an unparalleled window to new physics coupling to the QCD sector via quarks or gluons, with a discovery reach that could enhance existing and proposed experiments over a range of frequencies in the direction of well-motivated parameter space.

This study examines the behavior of test particles within the space-time of a non-rotating black hole (BH) possessing fundamental scalar hair. The geometry expands the standard Schwarzschild solution within scalar-tensor frameworks, defined by a charge Q and coupling hair constants α and Λ, which alter the gravitational potential and space-time configuration. Through the integration of analytical techniques and numerical simulations, we obtain precise formulations for conserved quantities, including energy and angular momentum, and examine the impact of scalar hair on the effective potential, the stability of circular orbits, and the positioning of the innermost stable circular orbits (ISCOs). Our results show that increasing the scalar charge or coupling strengths deepens the effective potential, reduces the ISCOs radii, and lowers the angular momentum required for stable orbits. We analyze the effective force and demonstrate its increased attractive nature under the influence of a scalar field. Through geodesic integration, we simulate the exact particle trajectories, revealing broader and more distinct orbits compared to the Schwarzschild BH model. In this case, we also study small harmonic oscillations around stable orbits, deriving radial, vertical, and orbital frequencies for both local and distant observers. In addition, the frequency of periastron precession decreases with increasing scalar hair parameters, suggesting potential observational signatures in systems with quasi-periodic oscillations (QPOs).

In this work, we shall consider Higgs inflationary Einstein–Gauss–Bonnet theories that are compatible with the GW170817 event, which dictates that the gravitational wave speed of primordial tensor perturbations must satisfy the constraint [Formula: see text]. We consider Einstein–Gauss–Bonnet theories that yield directly [Formula: see text] for which theories, the scalar potential and the non-minimal Gauss–Bonnet scalar coupling function are related. We assume that the non-minimal Gauss–Bonnet scalar coupling function is identical with the Higgs potential, and we confront the resulting theory with the ACT data, to determine whether the theory is viable. As we show, the resulting theoretical framework is viable and compatible with the ACT data and the updated Planck constraints on the tensor-to-scalar ratio.

High-resolution 1H NMR of rigid solids is now routinely observed under fast magic angle sample spinning (MAS). Nevertheless, the spectral resolution of 1H nuclei bonded to 14N is often compromised by residual dipolar splitting (RDS) and scalar coupling between 1H and 14N. Given the ubiquity of the NH moiety and the high natural abundance of both nuclei, RDS broadening poses a widespread practical challenge. Heteronuclear 14N decoupling during 1H acquisition is therefore essential for enhancing the spectral resolution. Previously, we demonstrated that low-power 14N CW decoupling via 70 kHz MAS improves the 1H signal intensity by ∼20% and narrows 1H line widths by ∼180 Hz but under stringent on-resonance 14N irradiation. Offset-tolerant 14N decoupling sequences are necessary to achieve good decoupling in samples with multiple 14N sites. Here, we assess several amplitude-modulated decoupling schemes, adapted from solution NMR. Experiments and numerical simulations determine that SUSAN1 (with tp = 10 μs and ν14N = 15-23 kHz) provides the best broadband 14N decoupling performance. Furthermore, an empirical correlation is established between pulse length and selective band-limited and non-selective broadband 14N decoupling behavior under low-power and fast MAS conditions.

A bstract In this work, we investigate monophoton signatures arising from dark matter via a 2 → 3 scattering process χ + N → χ + N + γ that is mediated by a virtual scalar and a Standard Model photon. Since the final-state photon carries a large fraction of the initial dark matter’s energy, this process offers a compelling handle for probing scalar portal dark matter scenarios. Their distinctive energy, angular, and timing distributions allow for effective separation of signal from neutrino-induced backgrounds. We analyze several models featuring different couplings to the scalar mediator, with the scalar photon coupling serving as the common detection channel. To distinguish between the models, we further examined their distinct spatial distributions. We considered the flux of dark matter produced both at the target and absorber of neutrino facilities such as the BNB, NuMI, and LBNF, and investigated the sensitivities at the ongoing SBND, ICARUS-NuMI, and future DUNE ND detectors. We further investigated the differences in the DM fluxes arising from various production mechanisms, as well as the distinctions between the target and absorber contributions. Our results demonstrate that the sensitivities at the considered experiments, especially DUNE ND, can place significantly improved constraints on viable parameter space in various scenarios.

We compute the running of the mass of a neutral boson and of its self-coupling in a simple model describing the self-interaction of three scalars, one of them neutral and the other two electrically charged, subject to the effects of a magnetic field, as functions of the field strength, at one-loop order. We resort to the environmentally friendly renormalization group approach, where the flow variable is taken as that describing the environmental conditions, in this case, the strength of the magnetic field. We find the magnetic field dependent mass and coupling beta functions and use them to set up the differential equations satisfied by the neutral scalar mass and coupling. We solve the resulting system of coupled equations both numerically and also analytically in the small-mass approximation. We find that the neutral scalar mass increases, while the coupling decreases with increasing field strength. The study is intended to set up the ideas to later use them in more sophisticated theories such as QED and QCD.

We investigate the effects of dark scalar- and vector-mediated interactions on dark matter admixed neutron stars, employing the two-fluid formalism. We adopt three different nuclear equations of state—BSk22, MPA1 and APR4—to describe the baryonic sector, while the dark component consists of fermionic particles within a relativistic mean field framework. We consider both linear and quadratic scalar interactions with the dark fermion, including a quartic self-interaction in the latter case. The parameters of the dark matter (DM) models are inferred via a Bayesian analysis that incorporates data from NICER observations and binary neutron star merger detections. The neutron star configurations obtained from the selected model parameters develop dark matter cores, leading to more compact objects with smaller masses and radii. Our findings suggest that scalar interactions generally have a weaker impact on the stellar structure compared to vector-mediated ones, though quantitative differences arise. In particular, quadratic scalar couplings suppress the net attractive interaction, allowing for larger dark matter fractions to be accreted. We also compute the sound speed of DM, finding that the scalar and quadratic interactions modify the stiffness of the dark equation of state while respecting causality: vector repulsion enhances the sound speed, whereas scalar attraction tends to soften it. We compare our results with GW1708017, GW190425 and NICER data and constrain DM couplings and mass.

Monoclonal antibodies are the cornerstone biopharmaceuticals whose safety and efficacy critically depend on their higher-order structure (HOS). Nuclear magnetic resonance (NMR) spectroscopy has emerged as a promising tool for HOS evaluation, yet its application has largely relied on fingerprinting approaches without residue-level interpretation. Here, we report site-specific assignments of methyl resonances in the Fc region of human IgG1, established through amino acid-selective labeling and correlation with backbone resonances using scalar coupling and NOE connectivities, further supported by mutagenesis. These assignments allowed us to identify glycoform-dependent spectral variations, including distinct signatures of core fucosylation and terminal galactosylation, as well as an Fc-specific amino acid substitution. Importantly, these spectral probes were detectable even in antibodies at natural isotopic abundance, enabling practical applications to therapeutic products without isotopic labeling. Furthermore, dynamic filtering highlighted methyl resonances from hinge and receptor-binding residues with elevated mobility, providing localized insights into functional sites. Collectively, our results establish unlabeled methyl NMR as a robust platform for sensitive and practical HOS assessment of therapeutic antibodies. This approach is broadly applicable to monitor glycosylation heterogeneity, chemical modifications, and batch-to-batch consistency, thereby offering a valuable framework for development and quality control of both innovative biopharmaceuticals and biosimilars.

In this work, we use neutrino masses as a probe of the neutrino-light-quark effective scalar interactions. It is found that neutrinos can acquire masses not only from the usual light quark loop corrections, but also from the light quark condensates. The latter contribution has been overlooked in the literature. We show that both contributions are comparable for operators involving <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>u</a:mi> </a:math> and <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>d</c:mi> </c:math> quarks, while quark loop corrections dominate for operators involving the <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mi>s</e:mi> </e:math> quark. Using the low-energy effective field theory extended with light right-handed neutrinos and matching to chiral perturbation theory, we systematically analyze these contributions, deriving constraints on the corresponding Wilson coefficients from neutrino mass bounds, coherent elastic neutrino-nucleus scattering, and light pseudoscalar meson invisible decays. Our analysis shows that electron neutrino mass measurements provide the most stringent constraints on these scalar couplings, significantly improving upon limits from other observables. The results highlight the importance of including both perturbative and nonperturbative contributions in complete phenomenological analyses of neutrino mass generation mechanisms.

We investigated how a magnetic topological defect affects the vacuum polarization of a charged massive scalar field in a flat (3+1)-dimensional space-time. The defect was modeled as an impenetrable-to-matter-field, finite-thickness tube with magnetic flux inside. We implemented the most general form of the Robin boundary condition on the surface of the magnetic tube, which enables a fully general analysis of the problem. We found that in flat space-time, the total vacuum energy generated by a magnetic topological defect depends on the curvature (ξ), except for special cases corresponding to the Dirichlet and Neumann boundary conditions. By contrast, when Robin’s general boundary conditions are imposed, the induced vacuum energy acquires an explicit dependence on the curvature coupling (ξ), which is significant even in flat space-time. A detailed study of the dependence of the effect on the boundary-condition parameter was carried out. The obtained results highlight the nontrivial role played by boundary conditions in vacuum polarization phenomena.

1H MRS lactate measurements are potentially valuable for studying energy metabolism in working skeletal muscle, but some technical obstacles need to be overcome. Spectral filtering to isolate the lactate signal from overlapping lipid resonances shows promise. We report a novel sequence with 3D localisation and a CH-selective double quantum filter (DQF) which enables dynamic postexercise single-shot measurement of cellular lactate T2 and clearance kinetics. Using a two-channel 1H transceiver coil at 7 T we applied a localized CH-selective DQF sequence to postexercise calf muscle in 11 subjects. In one leg acquisitions with constant and incrementing TE were interleaved to measure lactate decrease and T2. In the other the CH-selective sequence was interleaved with the nonselective variant. Postexercise DQF shows lactate clearly in 4 s single-shot spectra. Fitting was able to separate lactate concentration kinetics from T2 and J-modulation: clearance t1/2 = 162 ± 42 s and T2 = 138 ± 20 ms (mean ± SD); the scalar coupling constant fitted from time evolution was J = 16.6 ± 0.8 Hz, closely matching J = 16.5 ± 1.3 Hz derived from spectral splitting. Direct comparison showed 2.3 ± 0.9 times higher signal with the new CH-selective sequence. The new sequence improved lactate detection, enabling quantification from single shots postexercise with time resolution similar to 31P MRS. Measuring clearance and relaxation time constants of intramuscular lactate lays the groundwork for future absolute quantification and studies of intra- and extracellular lactate compartmentation based on dipolar coupling differences.

If axions simultaneously have the scalar couplings to the nucleons and pseudoscalar couplings to the electrons, it may mediate a <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi mathvariant="script">P</a:mi> </a:math> , <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"> <d:mi mathvariant="script">T</d:mi> </d:math> -violating interaction between the electronic shell and nuclei in the molecules. The polyatomic molecule RaOH, which is considered a promising platform for the <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mi mathvariant="script">P</g:mi> </g:math> , <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"> <j:mi mathvariant="script">T</j:mi> </j:math> -violation searches, is studied for its sensitivity to such interactions. Because of the long-range nature (on molecular scales) of the axion-mediated interaction, it is important whether the molecular parameter is sensitive to the vibration of the molecule. Our results imply that the impact of the vibrations on the axion-mediated electron-nucleon interaction in the molecule is similar to the impact on the short-range electron-nucleon scalar-pseudoscalar interaction studied earlier.

Synchronization is a universal phenomenon underpinning various natural processes and finds direct application in control engineering and photonics. Among several synchronization mechanisms, subharmonic entrainment (SHE) is a nonlinear synchronization phenomenon where an oscillator locks to an external drive with a fraction of the oscillator's frequency. While its mechanism is well understood for scalar couplings and finds application in the stabilization of ultrafast laser pulses, the potential of SHE with vectorial coupling is still unexplored. In this work, we demonstrate vector SHE (VSHE) using a passively mode-locked fiber laser as a testbed. We unveil the mechanism of vector SHE, in which weak external signals can entrain internal laser dynamics through vector coupling. Vector SHE presents in the form of synchronization between the subharmonic of mode-locking-driven oscillations and continuous wave (CW) signal with an evolving state of polarization. This CW signal, driven by the internal dynamics of the injected signal, causes VSHE with the frequencies' ratios of multiples of ten, resulting in a partially mode locking regime operation. Our findings offer new control techniques over mode-locking and additional dimension such as polarization states.