arXiv subjects

J. -P. Dedonder

Publications and source records attributed to J. -P. Dedonder.

At least 19 recordsLinked to original sources

arXiv2024

Amplitude analysis of $ B^0 \to K^0_S K^+ K^-$ decays in a quasi-two-body QCD factorization approach

The $B^0 \to K^0_S K^+ K^- $ decay amplitude is derived within a quasi-two-body QCD factorization framework in terms of kaon form factors and $B^0$ to two-kaon-transition functions. The final state kaon-kaon interactions in the $S$, $P$, and $D$ waves are taken into account. The unitarity constraints are satisfied for the two kaons in scalar states. It is shown that with few terms of the full decay amplitude one may reach a fair agreement with the total branching fraction and Dalitz-plot projections published in 2010 by the Belle Collaboration and in 2012 by the $\textit{BABAR}$ Collaboration. With 13 free parameters, our model fits the corresponding 422 data with a $χ^2$ of 583.6 which leads to a $χ^2$ per degree of freedom equal to 1.43. The dominant branching fraction arises from the $f_0(K^+K^-) K^0_S$ mode with 83.0$\%$ of the total branching. The next important mode is dominated by $ϕK^0_S$ plus small $ωK^0_S$ and $ρ^0 K^0_S$ modes with 18.3$\%$ of the total. Then follows the $a_0^\pm K^\mp$ mode with 6.2$\%$. Adding the other smaller modes, the total percentage sum is 107.7$\%$ which indicates a small interference contribution. In most regions of the Dalitz plot, our model gives rather small $CP$ asymmetry, but in some parts its values can be large and positive or negative. Its predicted total value is equal to -0.11$\%$. The calculated time dependent $\textit{CP}$-asymmetry parameters agree, within errors, with those obtained by the $\textit{BABAR}$ analysis. Our model amplitude can be the basis for a parametrization in experimental Dalitz plot analyses of LHCb and Belle II Collaborations.

hep-ph↗

arXiv2021

Dalitz plot studies of $D^0 \to K^0_S K^+ K^-$ decays in a factorization approach

The $\textit{BABAR}$ Collaboration data of the $D^0 \to K^0_S K^+ K^-$ process are analyzed within a quasi two-body factorization framework. In earlier studies, assuming $D^0$ transitions to two kaons and the transitions between one kaon and two kaons to proceed through the dominant intermediate resonances, we approximated them as being proportional to the kaon form factors. To obtain good fits, one has to multiply the scalar-kaon form factors, derived from unitary relativistic coupled-channel models or in a dispersion relation approach, by phenomenological energy-dependent functions. The final state kaon-kaon interactions in the $S$-, $P$- and $D$- waves are taken into account. All $S$-wave channels are treated in a unitary way. The $K^+K^-$ and $\bar K^0 K^+$ $S$-wave effective mass squared distributions, corrected for phase space, are shown, in a model-independent manner, to be significantly different. Then the $f_0(980)$ resonance must be included at variance with the BABAR analysis. The best fit has 19 free parameters and indicates i) the dominance of annihilation amplitudes, ii) a large dominance of the $f_0(980)$ meson in the near threshold $K^+K^-$ invariant mass distribution and iii) a sizable branching fraction to the $K_S^0 \ [ρ(770)^+ + ρ(1450)^+ + ρ(1700)^+] $ final states. An appendix provides an update of the determination of the isoscalar-scalar meson-meson amplitudes based on an enlarged set of data. A second appendix proposes two alternative fits based on scalar-kaon form factors calculated from the Muskhelishvili-Omnès dispersion relation approach. These fits have $χ^2$ quite close to that of the best fit but they show important contributions from both the $f_0$ and $a_0^0$ mesons and a weaker role of the $ρ^+$ mesons.

hep-ph↗

arXiv2019

Parametrizations of three-body hadronic $B$- and $D$-decay amplitudes

A short review of our recent work on amplitude parametrizations of three-body hadronic weak $B$ and $D$ decays is presented. The final states are here composed of three light mesons, namely the various charge $πππ$, $Kππ$ and $KK\bar K$ states. These parametrizations are derived from previous calculations based on a quasi-two-body factorization approach where the two-body hadronic final state interactions are fully taken into account in terms of unitary $S$- and $P$-wave $ππ$, $πK$ and $K \bar K$ form factors. They are an alternative to the isobar-model description and can be useful in the interpretation of CP asymmetries.

hep-ph↗

arXiv2018

Photon or meson formation in $J/ψ$ decays into $p {\overline{p}}$

The measurements of the $J/ψ\rightarrow γp \overline{p}$ decays by the BES Collaboration indicate an enhancement at the $p \overline{p}$ threshold which, however, is not present in the J/$ψ$ decays into $ωp \overline{p}$ and into $πp \overline{p}$. Here, two processes for describing the decays $J/ψ\rightarrow \mathcal{B} p \overline{p}$ where $\mathcal{B} = γ, ω$ are presented in some detail and the cases $\mathcal{B} =ϕ, π$ are briefly touched on. The first one, applied not only to the radiative decay to reproduce the threshold peak but also to the $ωp \overline{p}$ decay channel to improve the description of the spectrum, postulates a direct emission of the boson before the baryon pair is formed. The second process assumes that the boson $\mathcal{B}$ is emitted from the baryon pair following the $J/ψ$ decay and includes for the decays into $γp \overline{p}$ a final state nucleon-antinucleon interaction based on the Paris $N \overline{N}$ potential. The reproduction of the $p \overline{p}$ distribution in the $J/ψ\rightarrow ωp \overline{p}$ decays needs a final state interaction involving a $N(2050)\ 3/2^-$ resonance. The photon- and meson-emission rates are reproduced in a semi-quantitative way.

hep-ph↗

arXiv2017

Parametrizations of three-body hadronic $B$- and $D$-decay amplitudes in terms of analytic and unitary meson-meson form factors

We introduce parametrizations of hadronic three-body $B$ and $D$ weak decay amplitudes that can be readily implemented in experimental analyses and are a sound alternative to the simplistic and widely used sum of Breit-Wigner type amplitudes, also known as the isobar model. These parametrizations can be particularly useful in the interpretation of CP asymmetries in the Dalitz plots. They are derived from previous calculations based on a quasi-two-body factorization approach in which two-body hadronic final state interactions are fully taken into account in terms of unitary $S$- and $P$-wave $ππ$, $πK$ and $K \bar K$ form factors. These form factors can be determined rigorously, fulfilling fundamental properties of quantum field-theory amplitudes such as analyticity and unitarity, and are in agreement with the low-energy behaviour predicted by effective theories of QCD. They are derived from sets of coupled-channel equations using $T$-matrix elements constrained by experimental meson-meson phase shifts and inelasticities, chiral symmetry and asymptotic QCD. We provide explicit amplitude expressions for the decays $B^\pm \to π^+ π^- π^\pm$, $B \to K \ π^+ π^-$, $B^\pm \to K^+ K^-K^\pm$, $D^+ \to π^- π^+ π^+ $, $D^+ \to K^- π^+ \ π^+ $, $D^0 \to K^0_S \ π^+\ π^- $, for which we have shown in previous studies that this approach is phenomenologically successful, in addition, we provide expressions for the $D^0 \to K^0_S \ K^+ K^-$ decay. Other three-body hadronic channels can be parametrized likewise.

hep-ph↗

arXiv2014

Dalitz plot studies of D0 --> K0S pi+ pi- decays in a factorization approach

The presently available high-statistics data of the D0 --> K0S pi+ pi- processes measured by the Belle and BABAR Collaborations are analyzed within a quasi two-body QCD factorization framework. Starting from the weak effective Hamiltonian, tree and annihilation amplitudes build up the D0 --> K0S pi+ pi- decay amplitude. Two of the three final-state mesons are assumed to form a single scalar, vector or tensor state originating from a quark-antiquark pair so that the factorization hypothesis can be applied. The meson-meson final state interactions are described by K pi and pi pi scalar and vector form factors for the S and P waves and by relativistic Breit-Wigner formulae for the D waves. A combined chi^2 fit to a Belle Dalitz plot density distribution, to the total experimental branching fraction and to the tau^- --> K0S pi- nu_tau decay data is carried out to fix the 33 free parameters. These are mainly related to the strengths of the scalar form factors and to unknown meson to meson transition form factors at a large momentum transfer squared equal to the D0 mass squared. A good overall agreement to the Belle Dalitz plot density distribution is achieved. Another set of parameters fits equally well the BABAR Collaboration Dalitz plot model. The branching fractions of the dominant channels compare well with those of the isobar Belle or BABAR models.The lower-limit values of the branching fractions of the annihilation amplitudes are significant. Built upon experimental data from other processes, the unitary K pi and pi pi scalar form factors, entering our decay amplitude and satisfying analyticity and chiral symmetry constraints, are furthermore constrained by the present Dalitz plot analysis. Our decay amplitude could be a useful input for determinations of D0-D0bar mixing parameters and of the CKM angle gamma (or phi3).

hep-ph↗

arXiv2012

Final state strong interaction constraints on weak D0 -> K0S pi+ pi- decay amplitudes

Weak decay tree and annihilation - t-channel W - exchange amplitudes for the D0 -> K0S pi+ pi- process are calculated using quasi two-body QCD factorization approach and unitarity constraints. Final state strong kaon-pion and pion-pion interactions in S, P and D waves are described through corresponding form factors including many resonances. Preliminary results compare well with the effective mass distributions of the Belle and BABAR Collaboration analyses.

hep-ph↗

arXiv2012

Dalitz plot studies of D0 to K0S pi+ pi- decays

The availaible data on the D0 to K0S pi+ pi- decays are analysed in the framework of the quasi two-body QCD factorization approximation. The annihilation, via W-exchange, amplitudes are added to the weak-decay tree amplitudes. The doubly Cabibbo suppressed parts of the amplitudes are also considered. The strong interactions between the kaon-pion and pion-pion pairs in the S-, P- and D-final states are described in terms of the corresponding form factors. The kaon-pion or pion-pion scalar and vector form factors are constrained by other experimental data. Unitarity, analyticity and chiral symmetry are also used to obtain their functional forms. We go through a minimization procedure to reproduce the K0S pi-, K0S pi+ and pi+ pi- effective mass projections of the Dalitz plot distributions. The large number (27) of non-zero amplitudes leads to a large number of parameters. The resulting model distributions and branching fractions are compared to the accurate Belle Collaboration data.

hep-ph↗

arXiv2012

CP violation and strong pion-pion interactions in the weak B charged decays into three charged pions

An analysis of charged B decay data in a quasi two-body decay into a charged pion plus a S, P,or D state of two charged pions is performed in the QCD factorization framework. The short distance amplitudes are calculated including next-to-leading order corrections in the strong coupling constant for vertex and penguin contributions. The long distance amplitudes due to the two charged pion final state interactions are described by the pion non-strange scalar and vector form factors for the two-pion S- and P-wave states, respectively and by a relativistic Breit-Wigner formula for the D-wave state. We achieve a good fit of the data with only three parameters for the S wave, one for the P wave and one for the D wave. Our model gives a unified unitary description of the three scalar resonances, f_0(600), f_0(980) and f_0(1400) in terms of the pion scalar form factor. We predict for the B to f_2(1270) transition form factor a value of 0.098+-0.007 at a momentum transfer square equal to the pion-mass square.

hep-ph↗

arXiv2011

New physics in B_s^0 -> J/ψϕdecays?

After a brief review of B_s^0 - \bar B_s^0 oscillations, we discuss the weak decays B_s^0 -> J/ψϕand B_s^0 -> J/ψf_0(980) and the ratio R_{f_0/ϕ} of their decay rates in the light of recent measurements by the LHCb, D0 and CDF Collaborations. We point out that the experimental values for R_{f_0/ϕ} impose tight limits on new physics contributions to both decay channels.

hep-ph↗

arXiv2011

S-, P- and D-wave final state interactions and CP violation in B+- --> pi+- pi-+ pi+- decays

We study CP violation and the contribution of the strong pion-pion interactions in the three-body B+- --> pi+- pi-+ pi+- decays within a quasi two-body QCD factorization approach. The short distance interaction amplitude is calculated in the next-to-leading order in the strong coupling constant with vertex and penguin corrections. The meson-meson final state interactions are described by pion non-strange scalar and vector form factors for the S and P waves and by a relativistic Breit-Wigner formula for the D wave. The pion scalar form factor is calculated from a unitary relativistic coupled-channel model including pi pi, Kbar K and effective (2pi)(2pi) interactions. The pion vector form factor results from a Belle Collaboration analysis of tau- --> pi- pi0 nu_tau data. The recent B+- --> pi+- pi-+ pi+- BABAR Collaboration data are fitted with our model using only three parameters for the S wave, one for the P wave and one for the D wave. We find not only a sizable contribution of the S wave just above the pi pi threshold but also under the rho(770) peak a significant interference, mainly between the S and P waves. For the B to f_2(1270) transition form factor, we predict F^{Bf_2}(m_π^2)=0.098+-0.007. Our model yields a unified unitary description of the contribution of the three scalar resonances f_0(600), f_0(980) and f_0(1400) in terms of the pion non-strange scalar form factor.

hep-ph↗

arXiv2010

Are scalar mesons visible in B+- --> pi+pi-pi+- decays?

Two pion effective mass and helicity angle distributions in the charged B-meson decays into three charged pions are studied. The weak decay amplitudes are calculated in the framework of the QCD factorization approximation. The strong interactions between the pairs of pions are taken into account using scalar and vector pion form factors. The scalar form factors are constrained by data on pion-pion, kaon-antikaon and four pion production incorporated into a multichannel model of the coupled amplitudes. The vector form factor is obtained from the Belle Collaboration analysis of the tau- --> pi- pi0 nu_{tau} decays. The theoretical distributions of the dipion effective masses are compared with the corresponding results of the recent Dalitz plot analysis of B+- --> pi+pi-pi+- decays performed by the BABAR Collaboration. We find that the S-wave dipion amplitude, although much smaller than the P-wave amplitude, plays an important role even in the rho(770) mass range. We show that the helicity angle distribution is strongly asymmetric in the rho- meson range. This effect can be attributed to the broad f0(600)(or sigma) meson. The fact that the signal of the B+- --> f0(980) pi+- decay has not been found in the experimental analysis can be easily explained in our model since the relevant B decay amplitude is proportional to the scalar form factor which has a dip at the f0(980) mass. We obtain a unified unitary description of the contribution of the three scalar resonances f0(600), f0(980) and f0(1400) in terms of the pion non-strange scalar form factor.

hep-ph↗

arXiv2010

Scalar resonance effects on the B_s - \bar B_s mixing angle

The $B_s^0 \to J/ψϕ$ and $B_s^0 \to J/ψf_0(980)$ decays are analyzed within generalized QCD factorization including all leading-order corrections in $\alphas$. We point out that the ratio of our calculated widths, $Γ(B_s^0\to J/ψf_0(980), f_0(980)\to π^+π^-)/ Γ(B_s^0 \to J/ψϕ,ϕ\to K^+K^-)$, strongly indicates that $S$-wave effects in the $f_0(980)$'s daughter pions or kaons cannot be ignored in the extraction of the $B_s-\bar{B}_s$ mixing angle, $-2β_s$, from the $B_s^0 \to ϕJ/ψ$ decay amplitudes.

hep-ph↗

arXiv2010

K* resonance effects on direct CP violation in B -> pi pi K

Charged and neutral B decays into two charged pions and a charged or a neutral kaon are analyzed within the QCD factorization scheme where final state interactions before and after hadronization are included. The K*(892) and K*(1430) resonance effects are taken into account using the presently known pion-Kaon strange vector and scalar form factors. The weak decay amplitudes, which are calculated at leading power in Lambda_QCD/m_b and at the next-to-leading order in the strong coupling constant, include the hard scattering and annihilation contributions. The end point divergences of these weak final state interactions are controlled by two complex parameters determined through a fit to the available effective mass and helicity angle distribution, CP asymmetry and K*(892) branching ratio data. The predicted K*(1430) branching ratios and the calculated direct CP violation asymmetries are compared to the Belle and BABAR Collaboration data.

hep-ph↗

arXiv2009

On the structure of the X(1835) baryonium

The measurement by the BES collaboration of J/psi -> gamma p pbar decays indicates an enhancement at the p-pbar threshold. In another experiment BES finds a peak in the invariant mass of pi-mesons produced in the possibly related decay J/psi -> gamma pi+ pi- eta'. Using a semi-phenomenological potential model which describes all the N-Nbar scattering data, we show that the explanation of both effects may be given by a broad quasi-bound state in the spin and isospin singlet S wave. The structure of the observed peak is due to an interference of this quasi-bound state with a background amplitude and depends on the annihilation mechanism.

nucl-th↗

arXiv2009

The Scalar Meson f0(980) in Heavy-Meson Decays

A phenomenological analysis of the scalar meson f0(980) is performed that relies on the quasi-two body decays D and Ds -> f0(980)P, with P=pi, K. The two-body branching ratios are deduced from experimental data on D or Ds -> pi pi pi, K Kbar pi and from the f0(980) -> pi+ pi- and f0(980) -> K+ K- branching fractions. Within a covariant quark model, the scalar form factors F0(q2) for the transitions D and Ds -> f0(980) are computed. The weak D decay amplitudes, in which these form factors enter, are obtained in the naive factorization approach assuming a quark-antiquark state for the scalar and pseudoscalar mesons. They allow to extract information on the f0(980) wave function in terms of u-ubar, d-dbar and s-sbar pairs as well as on the mixing angle between the strange and non-strange components. The weak transition form factors are modeled by the one-loop triangular diagram using two different relativistic approaches: covariant light-front dynamics and dispersion relations. We use the information found on the f0(980) structure to evaluate the scalar and vector form factors in the transitions D and Ds -> f0(980), as well as to make predictions for B and Bs -> f0(980), for the entire kinematically allowed momentum range of q2.

hep-ph↗

arXiv2009

Scalar resonances in a unitary $π-π$ $S$-wave model for $D^+ \to π^+ π^- π^+$

We propose a model for $D^+ \to π^+ π^- π^+$ decays following experimental results which indicate that the two-pion interaction in the $S$-wave is dominated by the scalar resonances $f_0(600)/σ$ and $f_0(980)$. The weak decay amplitude for $D^+\to R π^+$, where $R$ is a resonance that subsequently decays into $π^+π^-$, is constructed in a factorization approach. In the $S$-wave, we implement the strong decay $R\to π^-π^+$ by means of a scalar form factor. This provides a unitary description of the pion-pion interaction in the entire kinematically allowed mass range $m_{ππ}^2$ from threshold to about 3 GeV$^2$. In order to reproduce the experimental Dalitz plot for $\Dppp$, we include contributions beyond the $S$-wave. For the $P$-wave, dominated by the $ρ(770)^0$, we use a Breit-Wigner description. Higher waves are accounted for by using the usual isobar prescription for the $f_2(1270)$ and $ρ(1450)^0$. The major achievement is a good reproduction of the experimental $m_{ππ}^2$ distribution, and of the partial as well as the total $\Dppp$ branching ratios. Our values are generally smaller than the experimental ones. We discuss this shortcoming and, as a byproduct, we predict a value for the poorly known $D\to σ$ transition form factor at $q^2=m_π^2$.

hep-ph↗

arXiv2008

Modeling electromagnetic form factors of light and heavy pseudoscalar mesons

The electromagnetic form factors of light and heavy pseudoscalar mesons are calculated within two covariant constituent-quark models, a light-front and a dispersion relation approach. We investigate the details and physical origins of the model dependence of various hadronic observables: the weak decay constant, the charge radius and the elastic electromagnetic form factor.

hep-ph↗