Resonance Contributions Research Articles

Four-body semileptonic decays B → D*Pℓ+νℓ with SU(3) flavor symmetry

Abstract We present a complete study of the B → D*Pℓ + ν ℓ (ℓ = e, μ, τ) decays with the non-resonant, the charmed axial vector resonant, and the charmed tensor resonant contributions using the SU(3) flavor symmetry. The relevant amplitude relations between the different decay modes are obtained by the SU(3) flavor symmetry. We then predict non-measured branching ratios of the B → D*Pℓ + ν ℓ decays with the non-resonant and the charmed resonant contributions by using the present experimental data of the B → D * P ℓ ′ + ν ℓ ′ ( ℓ ′ = e , μ ) decays within 2σ errors. We have found that B 0,+ → D*ηℓ + ν ℓ , B 0 , + → D * η ′ ℓ + ν ℓ , B s 0 → D s * η ℓ + ν ℓ , B s 0 → D s * η ′ ℓ + ν ℓ , and B 0 , + → D s * K ℓ + ν ℓ decays only receive non-resonant contributions. Decays B s 0 → D s * − π 0 ℓ + ν ℓ only receive D s 1 ′ resonant contributions. Other decays receive all three kinds of contributions, and these contributions are important in most decays.

Triboson production in the SMEFT

We study the production of three electroweak gauge bosons at the LHC, in the effective field theory of the standard model, at dimension six and next-to-leading order in QCD. We present results for inclusive cross-sections and differential distributions, finding that these QCD corrections are large, often vary across the phase-space and notably differ from those observed in the standard model. We then explore the potential of the recently observed triboson production processes for improving the sensitivity brought by electroweak precision observables and diboson data. The additional sensitivity we observe is dominated by resonant Higgs boson contributions, with decays to photon pairs in particular. A global analysis including Higgs boson data is therefore needed for a fair assessment of the future reach of triboson measurements on heavy new physics.

Investigation of Single Proton Dissociation

We consider the single proton diffraction dissociation at low missing masses focusing on the interplay between diffractive processes and resonance production. The model incorporates the concept of duality, where the observed cross sections are explained by both smooth background processes and discrete resonance contributions. At low missing masses MX, this approach leverages the Regge proton trajectory to account for the role of resonances in the cross section. Recent experimental data are used to refine model parameters, enhancing the accuracy of predictions for the differential cross section behavior in the resonance region.

Double and triple Higgs boson production to probe the electroweak phase transition

The production of three Higgs bosons could be a stretch goal for the LHC and a strategic case for future colliders. In this work, we analyse the phenomenological prospects of (neutral) triple Higgs compared to di-Higgs boson production, for a range of Higgs-sector extensions from a strong first-order electroweak phase transition perspective. In parallel, we include constraints from existing exotics and Higgs boson measurements that further limit the parameter space of such models. Resonance contributions offer large modifications in particular for triple Higgs production, albeit starting from a small SM expectation. With enhancements of order 40 over the SM, however, experimental efforts to obtain limits at the HL-LHC are well motivated and well placed. This is further highlighted by the potential of these processes to inform the investigation of the thermal history of our Universe. Published by the American Physical Society 2024

Resonance and non-resonant contributions to three-body Ds+ → π+π0η′ decay

Resonance and non-resonant contributions to three-body Ds+ → π+π0η′ decay

Anisotropy of energetic particles and thermal transport on internal kink stability in HL-3

The kinetic effects of Neutral Beam Injection (NBI) induced energetic particles (EPs) on the stability of internal kink mode are numerically investigated in the presence of anisotropic thermal transport for the new medium-sized tokamak HL-3, utilizing the MHD-kinetic hybrid code MARS-K (Liu Y Q et al. 2008 Phys. Plasmas 15 112503). It is found that after including realistic level of thermal transport, the kinetic effect of EPs on the mode stability is stabilizing in the co-NBI case while destabilizing in the counter-NBI case, in contrast to the similar stabilizing effect with both NBI cases at vanishing thermal transport. Detailed investigation reveals that this opposite effect with the two NBI cases is due to the different non-adiabatic transit resonance contributions of passing EPs in the presence of thermal transport. Anisotropic thermal transport can indirectly affect the non-adiabatic contribution of passing EPs by modifying the mode eigenvalue, which also contributes to the resonance condition between the mode and passing EPs. The non-perturbative approach adopted in the study also enables comparison of different modifications to the mode eigen-structure between the two NBI cases.

Study of the axial-vector and tensor resonant contributions to the D→VPℓ+νℓ decays based on SU(3) flavor analysis

Semileptonic three-body D→Mℓ+νℓ decays, non-leptonic M→VP decays, and semileptonic four-body D→M(M→VP)ℓ+νℓ decays are analyzed using the SU(3) flavor symmetry/breaking approach, where ℓ=e/μ, M=A/T, and A/T/V/P denote the axial-vector/tensor/vector/pseudoscalar mesons, respectively. In terms of SU(3) flavor symmetry/breaking, the decay amplitudes of the D→Mℓ+νℓ decays and the vertex coefficients of the M→VP decays are related. The relevant non-perturbative parameters of the D→Aℓ+νℓ, A→VP, and T→VP decays are constrained by the present experimental data, and the non-perturbative parameters of D→Tℓ+νℓ decays are taken from the results in the light-front quark model since no experimental data are available at present. The branching ratios of the D→Mℓ+νℓ, M→VP, and D→M(M→VP)ℓ+νℓ decays are then predicted. We find that some processes receive both tensor and axial-vector resonant contributions, while other processes receive only axial-vector resonant contributions. In cases where both kinds of resonant contributions exist, the axial-vector contributions are dominant. Some branching ratios with axial-vector resonance states are large, and they may be measured experimentally in the near future. In addition, the sensitivities of the branching ratios of D→Aℓ+νℓ and A→VP decays to the parameters are also investigated, and some decay branching ratios are found to be sensitive to the non-perturbative parameters.

The structure of the wave operator in four dimensions in the presence of resonances

We show that the wave operators for Schrödinger scattering in R4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mathbb {R}^4$$\\end{document} have a particular form which depends on the existence of resonances. As a consequence of this form, we determine the contribution of resonances to the index of the wave operator.

Light scalar quarkonia from Laplace sum rule at NLO

We review our results on light scalar quarkonia (q¯q and four-quark states) from (inverse) QCD Laplace sum rules (LSR) and their ratios R within stability criteria and including higher order perturbative (PT) corrections up to the (estimated) O(αs5). As the Operator Product Expansion (OPE) usually converges for D⩽6−8, we evaluated the QCD spectral functions at Lowest Order (LO) of PT QCD and up to the D=6 dimension vaccum condensates. We request that the optimal results obey the constraint: Pole (Resonance) contribution to the spectral integral is larger than the QCD continuum one which excludes an on-shell mass around (500−600)MeV obtained for values of the QCD continuum threshold tc⩽(1∼1.5)GeV2. Our results for the different assignments of the scalar mesons are compiled in Tables 1 to 3.

Elasticity and modal effects on the optimal performance of micro-perforated multi-layered absorbers

Multi-layered wall-treatments with thin lightweight micro-perforated panels offer a potential solution to achieve broadband noise absorption while complying with mass saving and compactness. This study examines how vibrational effects, often neglected, may impede the wideband acoustical performance of such partitions, made up of a distribution of either periodic or graded micro-perforated membranes or panels. The impedance translation method and a scattering matrix analysis have been implemented. It is found that the elasticity behavior of thin micro-perforated membranes has a beneficial effect on the acoustical efficiency of the partitions. The contributions of the individual acoustical resonances tend to merge if the elasticity effects are accounted for. If the partition is optimized, near-constant high absorption and low transmission values are obtained over a wide frequency range. A more robust design involves partitions made up of micro-perforated panels. It was observed that the first volumetric volumetric mode of the panels modifies the absorption properties of the partition. It cross-couples with the acoustical resonances and redistributes their spectral locations. This structural resonance sets an upper frequency bound, below which the partition achieves a high broadband performance. It should be accounted for when setting the frequency limits of the total dissipation to be optimized.

Search for the rare decay of charmed baryon Λc+ into the pμ+μ− final state

A search for the nonresonant Λc+→pμ+μ− decay is performed using proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the LHCb experiment, corresponding to an integrated luminosity of 5.4 fb−1. No evidence for the decay is found in the dimuon invariant-mass regions where the expected contributions of resonances is subdominant. The upper limit on the branching fraction of the Λc+→pμ+μ− decay is determined to be 2.9(3.2)×10−8 at 90%(95%) confidence level. The branching fractions in the dimuon invariant-mass regions dominated by the η, ρ and ω resonances are also determined. © 2024 CERN, for the LHCb Collaboration 2024 CERN

New approach to finding invisible states in e+e− annihilation and application to BESIII data

We compare precision e+e−→μ+μ− cross section measurements by BESIII in the Ecm=3.8–4.6 GeV range, to predictions based on measured Rhad data. The consistency is poor (p-value <0.012). Allowing for resonance contributions not seen in Rhad gives an excellent fit. The 4.6σ state required at 4421 MeV suggests that a substantial portion of ψ(4415) decays are not identified, while the 3.2σ structure at 4211 MeV, if confirmed, points to a new, very narrow resonance. This analysis shows the power of precision e+e−→μ+μ− measurements to uncover or probe otherwise difficult to access states. Published by the American Physical Society 2024

Enhanced four-band absorption in a tunable graphene subwavelength grating structure for photodetection

This paper investigates a sub-wavelength multilayer dielectric grating structure based on a simple metasurface, achieving dynamically switchable four-band absorption enhancement. This enhancement spans the visible to near-infrared (NIR) range, with absorption exceeding 90%, representing nearly a 40-fold increase over the intrinsic absorption of a single graphene layer. The contributions of guided-mode resonance (GMR), optical Tamm state (OTS), and photonic crystal defect cavity resonance to the absorption spectra are analyzed separately, offering a method for independent multi-channel signal extraction. Additionally, we explore the impact of structural parameters on the absorption response and examine the broad-spectrum multiband detection mechanism. This mechanism, explained through the integration of resonant cavity perturbation theory and the dynamic tuning of absorption efficiency via graphene's Fermi energy levels, results in an independently tunable optical system for four key operating bands. These properties make the structure suitable for applications such as multiband biomedical photodetectors or components in optoelectronic devices with multiple operating bands.

ρ meson magnetic dipole moment from BaBar e+e−→π+π−π0π0 cross section measurement

We obtain the value of the magnetic dipole moment of the ρ meson, using data from the collaboration for the e+e−→π+π−2π0 process. The considered center of mass energy range is from 0.9 to 1.8 GeV. We describe the γ*→4π vertex using a vector meson dominance model, including the intermediate resonant contributions relevant at these energies. We find μρ=2.7±0.3 in e/2mρ units. We improve on the previous extracted value, where preliminary data from the same collaboration was used, by considering definite data, better grounded values of the parameters involved, and an explicit gauge invariant description of the process. Published by the American Physical Society 2024

Analysis of three-body decays B→D(V→)PP under the factorization-assisted topological-amplitude approach

Motivated by the accumulated experimental results on three-body charmed B decays with resonance contributions in , LHCb, and Belle (II), we systematically analyze B(s)→D(s)(V→)P1P2 decays with V representing a vector resonance (ρ,K*,ω, or ϕ) and P1,2 as a light pseudoscalar meson (pion or kaon). The intermediate subprocesses B(s)→D(s)V are calculated with the factorization-assisted topological-amplitude (FAT) approach and the intermediate resonant states V described by the relativistic Breit-Wigner distribution successively decay to P1P2 via strong interaction. Taking all lowest resonance states (ρ,K*,ω,ϕ) into account, we calculate the branching fractions of these decay modes as well as the Breit-Wigner-tail effects for B(s)→D(s)(ρ,ω→)KK. Our results agree with the data by , LHCb, and Belle (II). Among the predictions that are still not observed, there are some branching ratios of order 10−6–10−4 which are hopeful to be measured by LHCb and Belle II. Our approach and the perturbative QCD approach (PQCD) adopt the compatible theme to deal with the resonance contributions. What is more, our data for the intermediate two-body charmed B-meson decays in FAT approach are more precise. As a result, our results for branching fractions have smaller uncertainties, especially for color-suppressed emission diagram dominated modes. Published by the American Physical Society 2024

Nucleon electric and magnetic polarizabilities in holographic QCD

We analyze the resonance contributions to the generalized Baldin sum rule, namely the sum of the generalized electric and magnetic nucleon polarizabilities αE(Q2) and βM(Q2), within the holographic QCD model by Witten, Sakai, and Sugimoto (WSS). In particular, we account for the contributions from the first low-lying nucleon resonances with spin-1/2 and spin-3/2 and both parities. After having extrapolated the WSS model parameters to fit experimental data on baryonic observables, we compare our findings with alternative predictions in literature, finding a qualitative agreement with all of them. Moreover, at least for the proton case, where data are available, our results are in qualitative accordance with resonance contributions extracted from experimental nucleon-resonance helicity amplitudes. Published by the American Physical Society 2024

Broadband light trapping in perovskite solar cells: Optimization and enhancement through exploiting multi-resonant Mie resonators

We present multi-resonant Mie resonators comprising dielectric nanopyramid arrays (DNPAs) for efficient broadband light trapping (LT) in perovskite solar cells (PSCs). Absorption in a 100 nm-thick active layer is significantly enhanced over a broad range of wavelengths through the simultaneous resonant excitation of electric and magnetic moments. Through optimization, a PSC integrated with a front-located DNPA LT structure having a base edge of 320 nm and a spacing of 180 nm at an aspect ratio of 1.5 yields a short-circuit current density (Jsc) of 18.13 mA/cm2, which is about 29 % higher than that of a planar PSC. Multipole resonance contributions and radiation patterns of DNPs are also investigated. The spectral overlap of the multipole resonances of the DNPAs can be easily tuned, thereby providing performance enhancements in diverse applications, such as nanoantennas, metasurfaces, photodiodes, and other solar cells.

Higgs interference effects in top-quark pair production in the 1HSM

We present a next-to-leading-order (NLO) study of the process pp (→ {h1, h2}) →tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document} + X in the 1-Higgs-singlet extension of the Standard Model with an additional heavy Higgs boson h2 that mixes with the light Higgs boson h1. This process is subject to large interference effects between loop-induced Higgs-mediated amplitudes and the QCD continuum background which tend to overcompensate any resonance contributions. A reliable modelling of the resulting top-pair invariant mass shapes requires the inclusion of higher-order QCD corrections, which are presented here. The computation of these NLO corrections is exact in all contributions but in the class of non-factorisable two-loop diagrams which are included in an approximate way such that all infrared singular limits are preserved. We present numerical results for several benchmark points with heavy Higgs masses in the range 700–3000 GeV considering the production of stable top quarks. We find that the interference effects dominate the BSM signal yielding sharp dip structures instead of resonance peaks. The significance and excludability of the BSM effect is explored for the LHC Run 2, Run 3 and HL-LHC.

Photoionization of hydrogen halides using the R-matrix method

Abstract In this study, we use the UK Molecular R-matrix (UKRMol) codes in the close-coupling approximation to examine the photoionization of hydrogen halides (hydrogen fluoride, hydrogen chloride, and hydrogen bromide). This article reports the total and partial photoionization cross sections for the X2Π, A2Σ+, and B2Σ+ ionic states of these halides. The calculated cross sections are compared with the available literature, which does not accurately represent the effective cross sections near the threshold region, which is dominated by the Rydberg series autoionization resonances converging to the A2Σ+ ionic state. There seems to have been minimal effort to investigate the Rydberg-bound states of these halides. Meanwhile, the R-matrix approaches have traditionally excelled at characterizing such studies. This indicates the effectiveness of this method for molecular photoionization as well as for understanding the resonant contribution to the photoionization cross sections. The detailed cross sections calculated comprise the complex autoionizing resonance structures capable of significantly contributing to the computations of total photoionization rates, which are necessary to maintain a steady state of ionization in astrophysical plasmas. Comparisons with the experimental measurements and the theoretical data generally show reasonable agreement across the reported energy range.

Quantitative Signal Analysis of Sum-Frequency Scattering Experiments from Aerosol Surfaces.

Droplet interfaces are instrumental in processes of biology, engineering, production, and environmental systems. The chemical and physical properties of heterogeneous interfaces are known to be different from those of their underlying bulk phases, and different again when considering the curved surface of submicron aerosol droplets. The recently developed technique of vibrational sum-frequency scattering (VSFS) spectroscopy from airborne particles has emerged as an interface-specific method for the in situ analysis of this unique system. While the technique has shown promise in debut works, a quantitative analysis of the VSFS system has not yet been performed. Here we provide a comprehensive analysis of a VSFS spectrometer with reference to the well-documented planar analog. We decompose the VSFS signal into coherent and incoherent as well as resonant and nonresonant components as a function of incident pulse delay time. We then quantify and compare resonant and nonresonant VSFS and VSFG experimental data using the same laser and detection systems. Using the air/water interface as a guide, we show that the resonant and nonresonant contributions to the SF responses are comparable for the two systems by extracting second-order susceptibilities and hyperpolarizabilities, and using them to estimate single-particle susceptibilities. A quantitative analysis of the signal detection systems for the scattering and planar geometries is made, and conversion efficiencies for VSFG, VSFS, and other nonlinear scattering experiments are compared. Lastly, the possibility of a low-repetition (1 kHz) VSFS spectrometer is considered, determining that it may be possible with modern laser technology but is inevitably less efficient than a high-repetition (100 kHz) system. Though this multistep analysis we obtain a better understanding of the components of the VSFS signal from aerosol particles, further validate the feasibility of the experiments, and provide insight to those wishing to conduct similar experiments and how they may be improved.