P-wave Contribution Research Articles

S -wave contribution to rare D0→π+π−ℓ+ℓ− decays in the standard model and sensitivity to new physics

Physics of the up-type flavor offers unique possibilities of testing the standard model (SM) compared to the down-type flavor sector. Here, we discuss SM and new physics (NP) contributions to the rare charm-meson decay D0→π+π−ℓ+ℓ−. In particular, we discuss the effect of including the lightest scalar isoscalar resonance in the SM picture, namely, the f0(500), which manifests in a big portion of the allowed phase space. Other than showing in the total branching ratio at an observable level of about 20%, the f0(500) resonance manifests as interference terms with the vector resonances, such as at high invariant mass of the leptonic pair in distinct angular observables. Recent data from LHCb optimize the sensitivity to P-wave contributions that we analyze in view of the inclusion of vector resonances. We propose the measurement of alternative observables that are sensitive to the S-wave and are straightforward to implement experimentally. This leads to a new set of null observables that vanish in the SM due to its gauge and flavor structures. Finally, we study observables that depend on the SM interference with generic NP contributions from semileptonic four-fermion operators in the presence of the S-wave. Published by the American Physical Society 2024

Exploring Light Meson Resonances in Two-Pion Photoproduction: A Regge Formalism Analysis

In the domain of hadron spectroscopy, the investigation of meson resonances plays a pivotal role. This study focuses on the significance of twopion photoproduction as a prominent avenue for studying meson resonances in the ππ system. By employing the Regge formalism, our model incorporates the background contribution from the well-known “Deck Mechanism” and emphasizes the significant ρ(770) resonance, representing the P-wave contribution arising from pomeron and f2 exchanges. The model is extended by accounting for scalar mesons, namely σ, f0(980) and f0(1370), contributing to the S-wave behavior, as well as the tensor meson f2(1270) corresponding to the D-wave contributions, while also considering non-resonant P- and S-wave components. The model contains a number of free parameters, which are constrained from a global fit of the available experimental data for angular moments up to L = 2 for M = 0, …, 2. The fitted angular moments are compared with experimental data obtained from CLAS. The key physical insights gained from the model are summarized. Furthermore, we extract the t-dependence of the Regge amplitude residue function for the subdominant exchanges, shedding light on their contribution to the overall dynamics.

A unified description of the halo nucleus 37Mg from microscopic structure to reaction observables

Based on the structure input directly from the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc), we fully study reaction observables to search for halo evidence of 37Mg with the Glauber model. In this scheme, we evaluate the reaction cross sections of 20–37Mg bombarding a C target at 240 MeV/nucleon and find that most of the results agree well with the experimental data within 1σ uncertainty, especially good for the case of 37Mg. Our predicted doubling of the cross section change from 36Mg to 37Mg over that from 34Mg to 35Mg is consistent with a halo structure in 37Mg. Additionally, our calculated narrow longitudinal momentum distribution of 36Mg residues from 37Mg + 12C breakup agrees well with data and imply a nuclear size much larger than 35Mg. Furthermore, our study shows a dominant p-wave contribution to the longitudinal momentum distribution, supporting the conclusion that 37Mg is a p-wave halo nucleus. Our study provides the first unified description of the halo characteristics of 37Mg from nuclear structure to reaction dynamics.

Orbital and Skeletal Structure of a Single Molecule on a Metal Surface Unveiled by Scanning Tunneling Microscopy.

Atomic-scale spatial characteristics of a phthalocyanine orbital and skeleton are obtained on a metal surface with a scanning tunneling microscope and a CO-functionalized tip. Intriguingly, the high spatial resolution of the intramolecular electronic patterns is achieved without resonant tunneling into the orbital and despite the hybridization of the molecule with the reactive Cu substrate. The resolution can be fine-tuned by the tip-molecule distance, which controls the p-wave and s-wave contribution of the molecular probe to the imaging process. The detailed structure is deployed to minutely track the translation of the molecule in a reversible interconversion of rotational variants and to quantify relaxations of the adsorption geometry. Entering into the Pauli repulsion imaging mode, the intramolecular contrast loses its orbital character and reflects the molecular skeleton instead. The assignment of pyrrolic-hydrogen sites becomes possible, which in the orbital patterns remains elusive.

Excited doubly heavy baryon production via W+ boson decays

In this paper, decay widths of the doubly heavy baryons (${\mathrm{\ensuremath{\Xi}}}_{cc}$ and ${\mathrm{\ensuremath{\Xi}}}_{bc}$) production are theoretically calculated in the whole phase space through ${W}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Xi}}}_{cc}+\overline{c}+\overline{s}$ and ${W}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Xi}}}_{bc}+\overline{b}+\overline{s}$, within the framework of nonrelativistic QCD (NRQCD). Differential widths $d\mathrm{\ensuremath{\Gamma}}/d{s}_{12}$, $d\mathrm{\ensuremath{\Gamma}}/d{s}_{23}$, $d\mathrm{\ensuremath{\Gamma}}/d\mathrm{cos}{\ensuremath{\theta}}_{12}$, and $d\mathrm{\ensuremath{\Gamma}}/d\mathrm{cos}{\ensuremath{\theta}}_{13}$ are also given. In addition to the ordinary S-wave contributions for the baryons, we specifically calculate P-wave contributions as a comparison, namely the high excited states of the intermediate diquark, including $[{^{1}P}_{1}]$ and $[{^{1}P}_{J}]$ (with $J=0,1,2$) in both color antitriplet state $\overline{\mathbf{3}}$ and color sextuplet state $\mathbf{6}$. It shows that the contribution from the P-wave is about one order lower than the S-wave. According to the results, we can expect plentiful events produced at the LHC, i.e., $3.69\ifmmode\times\else\texttimes\fi{}{10}^{5}\text{ }\text{ }{\mathrm{\ensuremath{\Xi}}}_{cc}$ events and $4.91\ifmmode\times\else\texttimes\fi{}{10}^{4}\text{ }\text{ }{\mathrm{\ensuremath{\Xi}}}_{bc}$ events per year.

K̅N interaction, p-wave terms

The inclusion of new ingredients that are expected to be specially relevant at higher energies could reveal more information about the physics behind the NLO terms of the chiral Lagrangian. In the present work, we explore the relevance of including partial waves higher than the L = 0, which is usually the only component considered in the literature to study the K̅N scattering phenomenology. In particular, we focus on the p-wave contribution, the effect of which is expected to be non-negligible, as we aim at obtaining the K−p scattering amplitudes at higher energies, necessary to describe the ηΛ, ηΣ0, K0Ξ0 and K+Ξ− production reactions. Extending the K̅N interaction to p-wave components is also relevant for studies of bound K− mesons in nuclei since their local momentum can acquire sizable values.

P-wave contributions to B(s)→ψKπ decays in perturbative QCD approach * * Supported by the National Natural Science Foundation of China (11947013, 11605060, 11775117, 11547020); Ya Li is also Supported by the Natural Science Foundation of Jiangsu Province (BK20190508) and the Research Start-up Funding of Nanjing Agricultural University; Zhou Rui is Supported in part by the Natural Science Foundation of Hebei

We study the quasi-two-body decays by employing the perturbative QCD (PQCD) factorization approach, where the charmonia represents and . The corresponding decay channels are studied by constructing the kaon-pion distribution amplitude (DA) , which comprises important final state interactions between the kaon and pion in the resonant region. Relativistic Breit-Wigner formulas are adopted to parameterize the time-like form factor appearing in the kaon-pion DAs. The SU(3) flavor symmetry breaking effect resulting from the mass difference between the kaon and pion is taken into account, which makes significant contributions to the longitudinal polarizations. The observed branching ratios and the polarization fractions of are accommodated by tuning hadronic parameters for the kaon-pion DAs. The PQCD predictions for modes from the same set of parameters can be tested by precise data obtained in the future from LHCb and Belle II experiments.

Clinical determinants of the PR interval duration in Swiss middle-aged adults: The CoLaus/PsyCoLaus study.

BackgroundProlonged PR interval (PRi) is associated with adverse outcomes. However, PRi determinants are poorly known. We aimed to identify the clinical determinants of the PRi duration in the general population.HypothesisSome clinical data are associated with prolonged PRi.MethodsCross‐sectional study conducted between 2014 and 2017. Electrocardiogram‐derived PRi duration was categorized into normal or prolonged (>200 ms). Determinants were identified using stepwise logistic regression, and results were expressed as multivariable‐adjusted odds ratio (OR) (95% confidence interval). A further analysis was performed adjusting for antiarrhythmic drugs, P‐wave contribution to PRi duration, electrolytes (kalemia, calcemia, and magnesemia), and history of cardiovascular disease.ResultsOverall, 3655 participants with measurable PRi duration were included (55.6% females; mean age 62 ± 10 years), and 330 (9.0%) had prolonged PRi. Stepwise logistic regression identified male sex (OR 1.41 [1.02‐1.97]); aging (65‐74 years: OR 2.29 [1.61‐3.24], and ≥ 75 years: OR 4.21 [2.81‐6.31]); increased height (per 5 cm, OR 1.15 [1.06‐1.25]); hypertension (OR 1.37 [1.06‐1.77]); and hs troponin T (OR 1.67 [1.15‐2.43]) as significantly and positively associated, and high resting heart rate (≥70 beats/min, OR 0.43 [0.29‐0.62]) as negatively associated with prolonged PRi. After further adjustment, male sex, aging and increased height remained positively, and high resting heart rate negatively associated with prolonged PRi. Hypertension and hs troponin T were no longer associated.ConclusionIn a sample of the Swiss middle‐aged population, male sex, aging and increased height significantly increased the likelihood of a prolonged PRi duration, whereas a high resting heart rate decreased it.

Quasi-two-body decays B_{(s)}rightarrow K^*(892)hrightarrow Kpi h in perturbative QCD approach

We extend our recent works on the P-wave two-pion resonant contributions to the kaon-pion cases in the hadronic charmless B meson decays by employing the perturbative QCD approach. The concerned decay modes are analysed in the quasi-two-body framework by parameterizing the kaon-pion distribution amplitude Phi _{K pi }^mathrm{P}, which contains the final state interactions between the kaon and pion in the resonant region. The relativistic Breit–Wigner formula for the P-wave resonant state K^*(892) is adopted to parameterize the time-like form factor F_{Kpi }. We calculate the CP-averaged branching ratios and direct CP-violating asymmetries of the quasi-two-body decays B_{(s)}rightarrow K^*(892) hrightarrow Kpi h, with h=(pi , K), in this work. It is shown that the agreement of theoretical results with the experimental data can be achieved, through which Gegenbauer moments of the P-wave kaon-pion distribution amplitudes are determined. The predictions in this work will be tested by the precise data from the LHCb and the future Belle II experiments.

Static response, collective frequencies, and ground-state thermodynamical properties of spin-saturated two-component cold atoms and neutron matter

The thermodynamical ground-state properties and static response in both cold atoms at or close to unitarity and neutron matter are determined using a recently proposed Density Functional Theory (DFT) based on the s-wave scattering length $a_s$, effective range $r_e$, and unitary gas limit. In cold atoms, when the effective range may be neglected, we show that the pressure, chemical potential, compressibility modulus and sound velocity obtained with the DFT are compatible with experimental observations or exact theoretical estimates. The static response in homogeneous infinite systems is also obtained and a possible influence of the effective range on the response is analyzed. The neutron matter differs from unitary gas due to the non infinite scattering length and to a significant influence of effective range which affects all thermodynamical quantities as well as the static response. In particular, we show for neutron matter that the latter response recently obtained in Auxiliary-Field Diffusion Monte-Carlo (AFDMC) can be qualitatively reproduced when the p-wave contribution is added to the functional. Our study indicates that the close similarity between the exact AFDMC static response and the free gas response might stems from the compensation of the $a_s$ effect by the effective range and p-wave contributions. We finally consider the dynamical response of both atoms or neutron droplets in anisotropic traps. Assuming the hydrodynamical regime and a polytropic equation of state, a reasonable description of the radial and axial collective frequencies in cold atoms is obtained. Following a similar strategy, we estimate the equivalent collective frequencies of neutron drops in anisotropic traps.

Superconducting proximity in three-dimensional Dirac materials: Odd-frequency, pseudoscalar, pseudovector, and tensor-valued superconducting orders

We find that a conventional s-wave superconductor in proximity to three dimensional Dirac material (3DDM), to all orders of perturbation in tunneling, induces a combination of s and p-wave pairing only. We show that the Lorentz invariance of the superconducting pairing prevents the formation of Cooper pairs with higher orbital angular momenta in the 3DDM. This no-go theorem acquires stronger form when the probability of tunneling from the conventional superconductor to positive and negative energy states of 3DDM are equal. In this case all the p-wave contribution except for the lowest order, identically vanish and hence we obtain an exact result for the induced p-wave superconductivity in 3DDM. Fierz decomposing the superconducting matrix we find that temporal component of the vector superconducting order and spatial components of the pseudo-vector order are odd-frequency pairing. We find that the latter is odd with respect to exchange of position and chirality of the electrons in the Cooper pair and is spin-triplet which is necessary for NMR detection of such an exotic pseudo- vector pairing. Moreover, we show that the tensorial order breaks into a polar vector and an axial vector and both of them are conventional pairing except for being spin-triplet. According to our study, for gapless 3DDM the tensorial superconducting order will be the only order which is odd with respect to the chemical potential {\mu}. Therefore we predict that a transverse p-n junction binds Majorana fermions. This effect can be used to control the neutral Majorana fermions with electric fields.

Chiral dynamics, S-wave contributions and angular analysis in Drightarrow pi pi ell bar{nu }

We present a theoretical analysis of the D^-rightarrow pi ^+pi ^- ell bar{nu } and bar{D}^0rightarrow pi ^+pi ^0 ell bar{nu } decays. We construct a general angular distribution which can include arbitrary partial waves of pi pi . Retaining the S-wave and P-wave contributions we study the branching ratios, forward–backward asymmetries and a few other observables. The P-wave contribution is dominated by rho ^0 resonance, and the S-wave contribution is analyzed using the unitarized chiral perturbation theory. The obtained branching fraction for Drightarrow rho ell nu , at the order 10^{-3}, is consistent with the available experimental data. The S-wave contribution has a branching ratio at the order of 10^{-4}, and this prediction can be tested by experiments like BESIII and LHCb. Future measurements can also be used to examine the pi –pi scattering phase shift.

Anapole dark matter annihilation into photons

In models of anapole dark matter (DM), the DM candidate is a Majorana fermion whose primary interaction with standard model (SM) particles is through an anapole coupling to off-shell photons. As such, at tree-level, anapole DM undergoes p-wave annihilation into SM charged fermions via a virtual photon. But, generally, Majorana fermions are polarizable, coupling to two real photons. This fact admits the possibility that anapole DM can annihilate into two photons in an s-wave process. Using an explicit model, we compute both the tree-level and diphoton contributions to the anapole DM annihilation cross section. Depending on model parameters, the s-wave process can either rival or be dwarfed by the p-wave contribution to the total annihilation cross section. Subjecting the model to astrophysical upper bounds on the s-wave annihilation mode, we rule out the model with large s-wave annihilation.

Complete Study of Hadroproduction of a ϒ Meson Associated with a Prompt J/ψ.

We present the first complete study of ϒ and prompt J/ψ production from single-parton scattering, including the complete O(α_{S}^{6}) color-singlet contribution, the O(α_{S}^{2}α^{2}) electroweak contribution, and the complete nonrelativistic S-wave and P-wave color-octet contribution as well as the feeddown contribution. Our study was motivated by the recent evidence reported by the D0 Collaboration of prompt J/ψ and ϒ simultaneous production at the Tevatron. With our complete evaluation, we are able to refine the determination of the double-parton scattering contribution made by the D0 Collaboration. We find that the effective cross section characterizing the importance of double-parton scatterings is σ_{eff}≤8.2 mb at 68%confidence level from the D0 measurement.

Form factors in [formula omitted] from QCD light-cone sum rules

The form factors of the semileptonic B→ππℓν¯ decay are calculated from QCD light-cone sum rules with the distribution amplitudes of dipion states. This method is valid in the kinematical region, where the hadronic dipion state has a small invariant mass and simultaneously a large recoil. The derivation of the sum rules is complicated by the presence of an additional variable related to the angle between the two pions. In particular, we realize that not all invariant amplitudes in the underlying correlation function can be used, some of them generating kinematical singularities in the dispersion relation. The two sum rules that are free from these ambiguities are obtained in the leading twist-2 approximation, predicting the B¯0→π+π0 form factors F⊥ and F∥ of the vector and axial b→u current, respectively. We calculate these form factors at the momentum transfers 0<q2≲12 GeV2 and at the dipion mass close to the threshold 4mπ2. The sum rule results indicate that the contributions of the higher partial waves to the form factors are suppressed with respect to the lowest P-wave contribution and that the latter is not completely saturated by the ρ-meson term.

P-wave contribution to third-order top-quark pair production near threshold

The next-to-leading order (NLO) P-wave Coulomb Green function contributes at third-order to top-pair production in e+e− collisions near threshold. In this paper we compute the NLO P-wave Green function in dimensional regularization, as required for a consistent combination with non-resonant production of the W+W−bb¯ final state, and present a phenomenological analysis of the P-wave contribution. We further briefly discuss squark production near threshold and top-pair production in γγ collisions, where no S-wave contribution is present, and the P-wave thus constitutes the dominant production process.

PR interval, P-wave duration, and mortality: New insights, additional questions

PR interval, P-wave duration, and mortality: New insights, additional questions

Chiral dynamics and S-wave contributions in semileptonic B decays

The flavor-changing neutral current process b → sl + l − is beneficial to testing the standard model and hunting for new physics scenarios. In exclusive decay modes like B → K * (892)l + l −, the S-wave effects may not be negligible and thus have to be reliably estimated. Using the scalar form factors derived from dispersion relations in two channels and matched to Chiral Perturbation Theory, we investigate the S-wave contributions in $ {{\overline{B}}^0}\to {K^{-}}{\pi^{+}}{l^{+}}{l^{-}} $ , with the Kπ invariant mass lying in the vicinity of the mass of K * (892), and B s → K − K + l + l − with m KK ~ m ϕ . We find that the S-wave will modify differential decay widths by about 10% in the process of $ {{\overline{B}}^0}\to {K^{-}}{\pi^{+}}{l^{+}}{l^{-}} $ and about 5% in B s → K − K + l + l −. A forward-backward asymmetry for the charged kaon in the final state arises from the interference between the S-wave and P-wave contributions. The measurement of this asymmetry offers a new way to determine the variation of the Kπ S-wave phase versus the invariant mass.

Investigation of thedd→3Henπ0reaction with the FZ Jülich WASA-at-COSY facility

An exclusive measurement of the dd -> 3He n \pi 0 reaction was carried at a beam momentum of p = 1.2 GeV/c using the WASA-at-COSY facility. For the first time data on the total cross section as well as differential distributions were obtained. The data are described with a phenomenological approach based on a combination of a quasi-free model and a partial wave expansion for three-body reaction. The total cross section is found to be \sigma(tot) = (2.89 +- 0.01(stat) +- 0.06(sys) +- 0.29(norm)) \mu b. The contribution of the quasi-free processes (with the neutron being target or beam spectator) accounts for 38% of the total cross section and dominates the differential distributions in specific regions of the phase space. The remaining part of the cross section can be described within a partial wave decomposition indicating the significance of p-wave contributions in the final state.

Atom-dimer scattering amplitude for fermionic mixtures with different masses:s-wave andp-wave contributions

We study near a Feshbach resonance, as a function of the mass ratio, the fermion-dimer scattering amplitude in fermionic mixtures of two fermion species. When masses are equal the physical situation is known to be quite simple. We show that, when the mass ratio is increased, the situation becomes much more complex. For the s-wave contribution we obtain an analytical solution in the asymptotic limit of very large mass ratio. In this regime the s-wave scattering amplitude displays a large number of zeros, essentially linked to the known large value of the fermion-dimer scattering length in this regime. We find by an exact numerical calculation that a zero is still present for a mass ratio of 15. For the p-wave contribution we make our study below the mass ratio of 8.17, where a fermion-dimer bound state appears. We find that a strong p-wave resonance is present at low energy, due to a virtual bound state, in the fermion-dimer system, which is a forerunner of the real bound state. This resonance becomes prominent in the mass ratio range around the one corresponding to the $^{40}$K - $^6$Li mixtures, much studied experimentally. This resonance should affect a number of physical properties. These include the equation of state of unbalanced mixtures at very low temperature but also the equation of state of balanced mixtures at moderate or high temperature. The frequency and the damping of collective modes should also provide a convenient way to evidence this resonance. Finally it should be possible to modify the effective mass of one of the fermionic species by making use of an optical lattice. This would allow to study the strong dependence of the resonance as a function of the mass ratio of the two fermionic elements. In particular one could check if the virtual bound state is relevant for the instabilities of these mixtures.