Search results for "Vector meson dominance"
showing 10 items of 30 documents
ρρinteraction in the hidden gauge formalism and thef0(1370)andf2(1270)resonances
2008
We have studied the interaction of vector mesons within the hidden gauge formalism and applied it to the particular case of the $\ensuremath{\rho}\ensuremath{\rho}$ interaction. We find a strong attraction in the isospin, spin channels $I$, $S=0$, 0 and 0, 2, which is enough to bind the $\ensuremath{\rho}\ensuremath{\rho}$ system. We also find that the attraction in the $I$, $S=0$, 2 channel is much stronger than in the 0, 0 case. The states develop a width when the $\ensuremath{\rho}$ mass distribution is considered, and particularly when the $\ensuremath{\pi}\ensuremath{\pi}$ decay channel is turned on. Using a regularization scheme with cutoffs of natural size, we obtain results in fair …
Observation of the Dalitz decayη′→γe+e−
2015
We report the first observation of the Dalitz decay eta' -> gamma e(+)e(-), based on a data sample of 1.31 billion J/psi events collected with the BESIII detector. The eta' mesons are produced via the J/psi -> gamma eta' decay process. The ratio (eta' -> gamma e(+)e(-))/Gamma (eta' -> gamma gamma) is measured to be (2.13 +/- 0.09(stat) +/- 0.07(sys)) x 10(-2). This corresponds to a branching fraction B(eta' -> gamma e(+)e(-)) = (4.69 +/- 0.20(stat) +/- 0.23(sys)) x 10(-4). The transition form factor is extracted and different expressions are compared to the measured dependence on the e(+)e(-) invariant mass. The results are consistent with the prediction of the vector meson dominance model.
Measurement of the branching fractions of the radiative charm decaysD0→K¯*0γandD0→ϕγ
2008
We present a measurement of the branching fractions for the Cabibbo-favored radiative decay D^0→K ^(*0) γ and the Cabibbo-suppressed radiative decay D^0→ϕγ. These measurements are based on a data sample corresponding to an integrated luminosity of 387.1 fb^(-1) and recorded with the BABAR detector at the PEP-II e^+e^- asymmetric-energy collider operating at center-of-mass energies 10.58 and 10.54 GeV. We measure the branching fractions relative to the well-studied decay D^0→K^-π^+ and find B(D^0→K ^(*0) γ)/B(D^0→K^-π^+)=(8.43±0.51±0.70)×10^(-3) and B(D^0→ϕγ)/B(D^0→K^-π^+)=(7.15±0.78±0.69)×10^(-4), where the first error is statistical and the second is systematic. This is the first observat…
Y(3940),Z(3930), and theX(4160)as dynamically generated resonances from the vector-vector interaction
2009
We apply a unitary approach together with a set of hidden‐gauge Lagrangians to study the vector‐vector interaction. Concretely, we focus on the sector with quantum numbers charm C = 0 and strangeness S = 0 in the region around 4000 MeV. We get five poles, three of which could be identified with the Y(3940), Z(3930) and X(4160). These poles appear with quantum numbers I = 0 and JPC = 0++,2++ and 2++, respectively, and can be considered as hadronic molecules made of D*D*, Ds*Ds*, decaying to a pair of light vectors, light‐heavy vector or pseudoscalar‐pseudoscalar.
Radiative decays of theY(3940),Z(3930), and theX(4160)as dynamically generated resonances
2011
We study the radiative decay properties of the charmoniumlike $X$, $Y$, and $Z$ mesons generated dynamically from vector-meson--vector-meson interaction in the framework of a unitarized hidden-gauge formalism. In the present work, we calculate the one- and two-photon decay widths of the hidden-charm $Y(3940)$, $Z(3930)$ [or $X(3915)$], and $X(4160)$ mesons in the framework of the vector-meson dominance formalism. We obtain good agreement with the experiment in case of the two-photon width of the $X(3915)$, which we associate to the ${2}^{+}$ resonance that we find at 3922 MeV. However, in view of discrepancies with a different approach that also considers the resonances as molecular states,…
Decay of axial-vector mesons into VP andPγ
2004
We propose a phenomenological Lagrangian for the decay of the SU(3) nonets of the axial-vector mesons of J{sup PC}=1{sup +-},1{sup ++} into a vector meson and a pseudoscalar constructed with tensor fields for the vector and axial-vector mesons. The formulation leads to a good reproduction of the different decay branching ratios and assuming vector meson dominance (VMD) it also leads to good results for the radiative decay of the a{sub 1} into pion and photon, and in agreement with the structure proposed in the chiral tensor formulation of radiative decay of axial-vector mesons. The two SU(3) parameters and the mixing angle of K{sub 1A} and K{sub 1B} needed to give the physical K{sub 1}(1270…
η→π0γγdecay within a chiral unitary approach
2003
We improve the calculations of the $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\eta}}{\ensuremath{\pi}}^{0}\ensuremath{\gamma}\ensuremath{\gamma}$ decay within the context of meson chiral Lagrangians. We use a chiral unitary approach for the meson-meson interaction, thus generating the ${a}_{0}(980)$ resonance and fixing the long standing sign ambiguity on its contribution. This also allows us to calculate the loops with one vector meson exchange, thus removing a former source of uncertainty. In addition we ensure the consistency of the approach with other processes, first, by using vector meson dominance couplings normalized to agree with radiative vector meson decays and, second, by …
Radiative decay into gamma-baryon of dynamically generated resonances from the vector-baryon interaction
2010
We study the radiative decay into gamma and a baryon of the SU(3) octet and decuplet of nine and ten resonances that are dynamically generated from the interaction of vector mesons with baryons of the octet and the decuplet, respectively. We obtain quite different partial decay widths for the various resonances, and for different charge states of the same resonance, suggesting that the experimental investigation of these radiative decays should bring much information on the nature of these resonances. For the case of baryons of the octet we determine the helicity amplitudes and compare them with experimental data when available.
Photoproduction of theωmeson on the proton near threshold
2015
An experimental study of omega photoproduction on the proton was conducted by using the Crystal Ball and TAPS multiphoton spectrometers together with the photon tagging facility at the Mainz Microtron MAMI. The gamma p -> omega p differential cross sections are measured from threshold to the incident-photon energy E-gamma = 1.40 GeV (W = 1.87 GeV for the center-of-mass energy) with 15-MeV binning in E-gamma and full production-angle coverage. The quality of the present data near threshold gives access to a variety of interesting physics aspects. As an example, an estimation of the omega N scattering length alpha(omega p) is provided.
Observation ofη′→ωe+e−
2015
Based on a sample of eta' mesons produced in the radiative decay J/psi -> gamma eta' in 1.31 x 10(9) J/psi events collected with the BESIII detector, the decay eta' -> omega e(+)e(-) is observed for the first time, with a statistical significance of 8 sigma. The branching fraction is measured to be B(eta' -> omega e(+)e(-)) = (1.97 +/- 0.34(stat) +/- 0.17(syst)) x 10(-4), which is in agreement with theoretical predictions. The branching fraction of eta' -> omega gamma is also measured to be (2.55 +/- 0.03(stat) +/- 0.16(syst)) x 10(-2), which is the most precise measurement to date, and the relative branching fraction B(eta' -> omega e(+)e(-))/B(eta' -> omega gamma) is determined to be (7.7…