Light Mesons Research Articles

Tetraquark nature of the a0(980) meson in hadronic D decays

The internal structure of the light scalar meson a0(980) is explored in the three-body D decays of D→a0(980)P→P1P2P through the intermediate state a0(980), where P denotes a pseudoscalar meson. The quasi-two-body D→a0(980)+P decays are governed by the external W-emission diagram in which a0(980)+ is emitted. The predicted branching fractions in the qq¯ model of a0(980) are too small by one to two orders of magnitude compared to the experiment as the amplitude is suppressed by the smallness of the a0(980)+ decay constant, while those for D+→a0(980)0P and D0→a0(980)−P are usually too large. These discrepancies can be resolved, provided that a0(980) is a tetraquark state. In this case, there exist two additional T-like topological amplitudes, denoted by T¯ and T˜, which readily account for the discrepancies. An important implication of the tetraquark model is that the Ds+→a0(980)+π0+a0(980)0π+ decay is not a purely W-annihilation process as in the qq¯ model of a0(980); it receives dominant contributions from T¯ newly noticed in this work. Therefore, measurements of (D,Ds+)→a0(980)P decays lend strong support to the tetraquark picture of a0(980). Published by the American Physical Society 2024

Charged pions asymmetry due to interference from the decay of light neutral axial mesons

Abstract Effective three meson couplings, based in flavor U(3) quark-antiquark
 interactions,
 are considered to describe two
light neutral axial meson
Strong decays, 
 $A \sim f_1(1285)$ and $f_{1S} (1420)$,
and the charged rho meson decay
in the following channels:
$A \to \rho^\mp (770)+ \pi^\pm$,
 $A\to a_0^\mp (980) +\pi^\pm$ and
$\rho^\pm \to \pi^\pm \pi^0$.
By considering neutral meson mixings, such as $f_1(1285) - a_1^0(1260)$, $f_{1S}(1420) - a_1^0(1260)$ and $\eta-\pi^0$ for the channels investigated, the leading three-meson interactions may lead to decay amplitudes that undergo interference and a resulting ratio of decay rate into charged pions, $\Gamma_{\pi^+}/\Gamma_{\pi^-}$, slightly smaller than one. For that it will be assumed that the produced charged vector mesons or charged scalar mesons undergo absorption, decay into channels without charged pions, or any other inelastic process that may suppress their decays into charged pions.

Heavy flavor-asymmetric pseudoscalar mesons on the light front

We extract the leading Fock-state light front wave functions of heavy flavor-asymmetric pseudoscalar mesons D, B, and Bc from their Bethe-Salpeter wave functions, based on the Dyson-Schwinger equations approach. We then study their leading-twist parton distribution amplitudes, generalized parton distribution functions, and transverse momentum-dependent parton distributions. The spatial distributions of the quark and antiquark on the transverse plane are presented, along with their charge and energy distributions on the light front. We find that in the considered mesons, the heavier quarks carry most of the longitudinal momentum fraction, resulting in narrow x distributions, while the lighter quarks play an active role in shaping the transverse distributions in both spatial and momentum space, exhibiting a duality that embodies characteristics of both light mesons and heavy quarkonium. Published by the American Physical Society 2024

Topological amplitudes of charmed baryon decays in the SU(3)F limit

Charmed baryon decay plays an important role in studying the weak and strong interactions. Topological diagram is an intuitive tool for analyzing the dynamics of heavy hadron decays. In this work, we investigate the topological diagrams of charmed baryon antitriplet (Bc3¯) decays into a light baryon octet (B8) and a light meson (M). A one-to-one mapping between the topological diagram and the invariant tensor is established. The topological diagrams of the Bc3¯→B8SM modes (where B8S and B8A are the q1↔q2 symmetric and antisymmetric octets) and the diagrams with a quark loop are presented for the first time. The completeness of topologies is confirmed by permutation. The linear relations of topologies are obtained by deriving the relation between the topological amplitudes constructed by the third- and second-rank octet tensors. It is found the topologies contributing to the Bc3¯→B8SM modes can be determined by the topologies contributing to the Bc3¯→B8AM modes, and vice versa. The equations of SU(3) irreducible amplitudes decomposed by topologies are derived through two different intermediate amplitudes. However, the inverse solution does not exist since the number of topologies exceeds number of SU(3) irreducible amplitudes. Applying this framework to the Standard Model, it is found there are thirteen independent SU(3) irreducible amplitudes contributing to the Bc3¯→B8M decays. Among these, four amplitudes associated with three-dimensional operators are significant for CP asymmetries. Considering the suppressions due to small Cabibbo-Kobayashi-Maskawa matrix elements and the Körner-Pati-Woo theorem, the branching fractions of charmed baryon decays are dominated by five SU(3) irreducible amplitudes in the SU(3)F limit. Quark-loop diagrams could enhance the U-spin breaking effects and increase the branching fraction difference of two decay channels. Systematic measurements of branching fractions of the singly Cabibbo-suppressed modes could help identify promising channels for searching for CP asymmetries in the charmed baryon sector. Published by the American Physical Society 2024

Interpretation of recently discovered single bottom baryons in the relativistic flux tube model

Following recent experimental progress in the study of bottom baryons, we systematically calculate the mass spectra of Λb, Ξb, Σb, Ξb′, and Ωb baryons with a quark-diquark picture in the framework of a relativistic flux tube model with spin-dependent interactions in the j-j coupling scheme. Furthermore, we calculate the strong decay width of bottom baryons decaying into a bottom baryon and a light pseudoscalar meson. Good agreement is found between the calculated masses and the experimentally available masses of singly bottom baryons. By analyzing both mass spectra and strong decay widths, we interpret Σb(6097) as a 1P(3/2−) state and Ξb(6100) as a 1P(1/2−) state of the Ξb baryon. The Ξb(6227) is identified to be an orbital excitation 1P of the Ξb′ baryon with JP=3/2−. Further, we determine Ξb(6327) and Ξb(6333) as a 1P(3/2−) state and 1P(5/2−) state, respectively, of Ξb′ baryon. From the obtained mass spectra, we construct the Regge trajectories in the (J,M2) plane, which are found to be essentially linear, parallel, and equidistant. Our predictions for higher orbital and radial excited states can help experimentalists identify missing excited states of singly bottom baryons. Published by the American Physical Society 2024

Predicting hidden bottom molecular tetraquarks with a complex scaling method

In the present work, we perform a coupled-channel analysis of B(s)(*)B¯(s)(*) systems with the one-boson-exchange potentials. We first study the I(JPC)=1(1+−) BB¯*/B*B¯* system to describe the Zb(10610) and Zb(10650) particles as molecular states and determine the reasonable range of cutoff parameter Λ. Then, other B(s)(*)B¯(s)(*) combinations with different quantum numbers are systematically investigated. Some bound states and resonances appear in the isoscalar systems, while only several shallow bound states exist for isovector systems. Far away from the excited conventional P-wave bottomium, these predicted states can be easily identified as exotic particles both theoretically and experimentally. Moreover, the ηb(nS)/ϒ(nS) plus light mesons are the excellent final states to search for the bound states, while the BB¯*+H.c. and B*B¯* channels are suitable for the resonances. We highly recommend that the LHCb and Belle II Collaborations hunt for these bottomoniumlike states in the future. Published by the American Physical Society 2024

Anomalous and linear holographic hard wall models for light unflavored mesons

In this work we consider anomalous and linear holographic hard wall (HW) models for light unflavored mesons inspired by the AdS/CFT correspondence. The anomalous dimensions depend on the logarithm of the spin S of the meson state and come from a semiclassical analysis of gauge/string duality. The anomalous HW model produces very good masses and good Regge trajectories for mesons compared with PDG data. Inspired by this anomalous HW model we also propose a phenomenological modification of the dimension of the boundary operators such that the model produces asymptotic linear Regge trajectories. Both anomalous HW models considered here present mass percentage deviations of less than 3%, when compared with PDG data. Published by the American Physical Society 2024

The study of hadronic rescattering on K*0 resonance yield in baryon-rich QCD matter

Abstract The effect of hadronic rescattering on $K^{*0}$ resonance yield can be studied by measuring $K^{*0}/K$ ratio as a function of centrality or multiplicity. This study investigates how the size of the system and the chemical composition (meson-meson versus meson-baryon interaction) of the matter formed in heavy-ion collisions impact the process of hadronic rescattering. It is shown that existing calculation of $K^{*0}/K$ ratio, which considers the interaction of $K^{*0}$ and $K$ mesons with only light mesons in the hadronic medium (neglecting interactions with baryons), fails to explain the measured $K^{*0}/K$ ratio at RHIC BES energies. To understand the multiplicity dependence of the $K^{*0}/K$ ratio at RHIC BES and SPS energies ($\sqrt{s_{NN}}$ $<$ 20 GeV), the Ultra Relativistic Quantum Molecular Dynamics (UrQMD) model is employed. UrQMD calculations suggest that for a given multiplicity, $K^{*0}/K$ is more suppressed in Au+Au collision at $\sqrt{s_{NN}}$ =7.7 GeV, compared to that in $\sqrt{s_{NN}}$ =200 GeV. This is possibly because of formation different type of QCD medium at 200 GeV and 7.7 GeV, and change in interaction cross-section between hadrons with change in particle type and energy.

Meson spectroscopy from spectral densities in lattice gauge theories

Spectral densities encode nonperturbative information that enters the calculation of a plethora of physical observables in strongly coupled field theories. Phenomenological applications encompass aspects of standard-model hadronic physics, observable at current colliders, as well as correlation functions characterizing new physics proposals, testable in future experiments. By making use of numerical data produced in a Sp(4) lattice gauge theory with matter transforming in an admixture of fundamental and 2-index antisymmetric representations of the gauge group, we perform a systematic study to demonstrate the effectiveness of recent technological progress in the reconstruction of spectral densities.To this purpose, we write and test new software packages that use energy-smeared spectral densities to analyze the mass spectrum of mesons. We assess the effectiveness of different smearing kernels and optimize the smearing parameters to the characteristics of available lattice ensembles. For concreteness, we analyze the Sp(4) lattice gauge theory with matter transforming in an admixture of fundamental and 2-index antisymmetric representations of the gauge group. We generate new ensembles for the theory in consideration, with lattices that have a longer extent in the time direction with respect to the spatial ones. We run our tests on these ensembles, obtaining new results about the spectrum of light mesons and their excitations. We make available our algorithm and software for the extraction of spectral densities, that can be applied to theories with other gauge groups, including the theory of strong interactions (QCD) governing hadronic physics in the standard model. Published by the American Physical Society 2024

Walking-dilaton hybrid inflation with B − L Higgs embedded in dynamical scalegenesis

We propose a hybrid inflationary scenario based on eight-flavor hidden QCD with the hidden colored fermions being in part gauged under U(1)B−L. This hidden QCD is almost scale-invariant, so-called walking, and predicts the light scalar meson (the walking dilaton) associated with the spontaneous scale breaking, which develops the Coleman-Weinberg (CW) type potential as the consequence of the nonperturbative scale anomaly, hence plays the role of an inflaton of the small-field inflation. The U(1)B−L Higgs is coupled to the walking dilaton inflaton, which is dynamically induced from the so-called bosonic seesaw mechanism. We explore the hybrid inflation system involving the walking dilaton inflaton and the U(1)B−L Higgs as a waterfall field. We find that observed inflation parameters tightly constrain the U(1)B−L breaking scale as well as the walking dynamical scale to be ~ 109 GeV and ~ 1014 GeV, respectively, so as to make the waterfall mechanism worked. The lightest walking pion mass is then predicted to be around 500 GeV. Phenomenological perspectives including embedding of the dynamical electroweak scalegenesis and possible impacts on the thermal leptogenesis are also addressed.

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

Coupled-channel J−− meson resonances from lattice QCD

We extend an earlier calculation within lattice QCD of excited light meson resonances with JPC=1−−,2−−,3−− at the SU(3) flavor point in the representation, by considering the representation. In this case the resonances appear in coupled-channel amplitudes, which we determine, establishing the relative strength of pseudoscalar-pseudoscalar to pseudoscalar-vector decays. Combining the new octet results with the prior results for the singlet, we perform a plausible extrapolation to the physical quark mass, and compare to experimental ρJ⋆,KJ⋆,ωJ⋆ and ϕJ⋆ resonances. Published by the American Physical Society 2024

Quark spin-orbit correlations in spin-0 and spin-1 mesons using the light-front quark model

We investigate the spin-orbital angular momentum correlations for the active quark inside the light and heavy mesons for both the spin-0 and spin-1 cases. These correlations can be derived from the generalized transverse-momentum-dependent distributions as well as the generalized parton distributions. We employ the overlap representation of light-front wave functions in the light-front quark model to calculate our analytical results. The dependence of spin-orbit correlations (SOCs) on the longitudinal momentum fraction x as well as the transverse-momentum-dependence k⊥ is graphically presented. Even though the SOCs have already been studied for the spin-0 pions and kaons in other approaches, no calculations for the other light and heavy spin-0 mesons have been reported in the literature. Further, the correlations for any of the light and heavy spin-1 mesons are studied for the first time in the present work. Published by the American Physical Society 2024

Interaction of exotic states in a hadronic medium: the Z c (3900) case

We investigate the interactions of the charged exotic state Z c (3900) in a hadronic medium composed of light mesons. We study processes such as Zcπ→DD¯ , Zcπ→D*D¯* , Zcπ→DD¯* and the inverse ones. Using effective Lagrangians and form factors calculated with Quantum Chromodynamics (QCD) sum rules (treating the Z c (3900) as a tetraquark) we estimate the vacuum and thermally-averaged cross-sections of these reactions. We find that the Z c (3900) has relatively large interaction cross sections with the constituent particles of the hadronic medium. After that, we use the production and suppression cross sections in a rate equation to estimate the time evolution of the Z c multiplicity. We include the Z c decay and regeneration terms The coalescence model is employed to compute the initial Z c multiplicity for the compact tetraquark configuration. Our results indicate that the combined effects of hadronic interactions, hydrodynamical expansion, decay and regeneration affect the final yield, which is bigger than the initial value. Besides, the dependence of the Z c final yield with the centrality, center-of-mass energy and the charged hadron multiplicity measured at midrapidity [dNch/dη(η<0.5)] is also investigated.

X(3872) to ψ(2S) yield ratio in heavy-ion collisions

In this work, we evaluate the X(3872) to ψ(2S) yield ratio (NX/Nψ(2S)) in Pb-Pb collisions, taking into account the interactions of the ψ(2S) and X(3872) states with light mesons in the hadron gas formed at the late stages of these collisions. We employ an effective Lagrangian approach to estimate the thermally averaged cross sections for the production and absorption of the ψ(2S) and use them in the rate equation to determine the time evolution of Nψ(2S). The multiplicity of these states at the end of the mixed phase is obtained from the coalescence model. The multiplicity of X(3872), treated as a bound state of (DD¯*+cc) and also as a compact tetraquark, was already calculated in previous works. Knowing these yields, we derive predictions for the ratio (NX/Nψ(2S)) as a function of the centrality, of the center-of-mass energy, and of the charged hadron multiplicity measured at midrapidity [dNch/dη(η&lt;0.5)]. Finally, we make predictions for this ratio in Pb-Pb collisions at sNN=5.02 TeV to be measured by the ALICE Collaboration in run 3. Our findings suggest that the molecular configuration generates a ratio compatible with the data, whereas the ratio obtained with the tetraquark configuration is 50 times smaller. Published by the American Physical Society 2024

Symmetries of spatial correlators of light and heavy mesons in high temperature lattice QCD

The spatial z correlators of meson operators in Nf=2+1+1 lattice QCD with optimal domain-wall quarks at the physical point are studied for seven temperatures in the range of 190–1540 MeV. The meson operators include a complete set of Dirac bilinears (scalar, pseudoscalar, vector, axial vector, tensor vector, and axial-tensor vector), and each for six flavor combinations (u¯d, u¯s, s¯s, u¯c, s¯c, and c¯c). In a recent paper [], I focused on the meson correlators of u and d quarks, and discussed their implications for the effective restoration of SU(2)L×SU(2)R and U(1)A chiral symmetries, as well as the emergence of approximate SU(2)CS chiral spin symmetry. In this work, we extend our study to meson correlators of six flavor contents, and first observe the hierarchical restoration of chiral symmetries in QCD, from SU(2)L×SU(2)R×U(1)A to SU(3)L×SU(3)R×U(1)A, and to SU(4)L×SU(4)R×U(1)A, as the temperature is increased from 190 to 1540 MeV. Moreover, we compare the temperature windows for the emergence of the approximate SU(2)CS symmetry in light and heavy vector mesons, and find that the temperature windows are dominated by the (u¯c,s¯c,c¯c) sectors. Published by the American Physical Society 2024

Predictions of the missing excited vector heavy–light mesons: the mass difference method

A prediction study for the not yet discovered cs¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$c\\overline{s}$$\\end{document} and bs¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$b\\overline{s}$$\\end{document} meson states of the 13D1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$1^{3}D_1$$\\end{document} quantum numbers is conducted, denoted as Ds\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D_s$$\\end{document} and Bs\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$B_s$$\\end{document}, respectively. By employing our method, both states of ground and excited vector mesons are considered, which predominantly correspond to the ground state vector mesons with quantum numbers n2S+1LJ=13S1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$n~ ^{2S+1}L_{J} = 1 ~ ^{3}S_1$$\\end{document} and to the orbitally excited vector mesons with quantum numbers n2S+1LJ=13D1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$n~ ^{2\\,S+1}L_{J} = 1~ ^{3}D_1$$\\end{document}. The considered method depends on the difference in the masses for the relevant states from orbitally and ground state vector mesons. Theoretical calculations are in good agreements with newly published data.

Flavor-spin symmetry of the PψN/HΩcccN and PψsΛ/HΩcccsΛ molecular states

Based on a contact Lagrangian that incorporates the SU(3) flavor and SU(2) spin symmetries, we discuss the symmetry properties of the interactions among the heavy flavor meson-baryon PψN, PψsΛ (with quark components [nc¯][nnc], [sc¯][nnc], or [nc¯][nsc]) systems and dibaryon HΩcccN, HΩcccsΛ (with quark components [nnc][ncc], [nnc][scc], or [nsc][ncc]) systems (n=u, d). The light quark components of the PψN (PψsΛ) and HΩcccN (HΩcccsΛ) systems have identical flavors, the interactions generated from the exchanges of light mesons in the PψN (PψsΛ) systems should be very similar to that of the HΩcccN (HΩcccsΛ) systems. We perform the single-channel and multichannel calculations on the PψN/PψsΛ/HΩcccN/HΩcccsΛ systems and introduce the SU(3) breaking effect to identify the different mass spectra among the PψN (HΩcccN) and PψsΛ (HΩcccsΛ) systems. We suggest two kinds of evidences for the existence of the flavor-spin symmetry among the heavy flavor PψN/HΩcccN/PψsΛ/HΩcccsΛ molecule community, i.e., the mass arrangements of the PψN/HΩcccN/PψsΛ/HΩcccsΛ mass spectra and the binding energies of the heavy flavor meson-baryon (dibaryon) systems attributed to the same contact potentials. Published by the American Physical Society 2024

Charmonium χc0 and χc2 resonances in coupled-channel scattering from lattice QCD

In order to explore the spectrum of hidden-charm scalar and tensor resonances, we study meson-meson scattering with JPC=0++,2++ in the charmonium energy region using lattice QCD. Employing a light-quark mass corresponding to mπ≈391 MeV, we determine coupled-channel scattering amplitudes up to around 4100 MeV considering all kinematically relevant channels consisting of a pair of open-charm mesons or a charmonium meson with a light meson. A single isolated scalar resonance near 4000 MeV is found with large couplings to DD¯, DsD¯s and the kinematically closed D*D¯* channel. A single tensor resonance at a similar mass couples strongly to DD¯, DD¯* and D*D¯*. We compare the extracted resonances to contemporary experimental candidate states, previous lattice results and theoretical modeling. In contrast to several other studies, we do not find any significant feature in the scalar amplitudes between the ground state χc0(1P) and the resonance found around 4000 MeV. Published by the American Physical Society 2024

Semileptonic W Decay to the B Meson with Lepton Pairs in Heavy Quark Effective Theory Factorization up to $\mathcal {O}(\alpha _s)$

Abstract Motivated by the study of heavy–light meson production within the framework of heavy quark effective theory (HQET) factorization, we extend the factorization formalism for a rather complicated process W+ → B+ℓ+ℓ− in the limit of a nonzero invariant squared mass of the dilepton, q2, at the lowest order in 1/mb up to $\mathcal {O}(\alpha _s)$. The purpose of the current study is to extend the HQET factorization formula for the W+ → B+ℓ+ℓ− process and subsequently compute the form factors for this channel up to next-to-leading-order corrections in αs. We explicitly show that the amplitude of the W+ → B+ℓ+ℓ− process can also be factorized into a convolution between the perturbatively calculable hard-scattering kernel and the nonperturbative yet universal light-cone distribution amplitude (LCDA) defined in HQET. The validity of the HQET factorization depends on the assumed scale hierarchy mW ∼ mb ≫ ΛQCD. Within the HQET framework, we evaluate the form factors associated with the W+ → B+ℓ+ℓ− process, providing insights into its phenomenology. In addition, we also perform an exploratory phenomenological study on W+ → B+ℓ+ℓ− by employing an exponential model for the LCDAs for the B+ meson. Our findings reveal that the branching ratio for W+ → B+ℓ+ℓ− is below 10−10. Although the branching ratios are small, this channel in high-luminosity LHC experiments may serve to further constrain the value of λB.