Search results for "Dominance"
showing 10 items of 360 documents
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…
Working group on goldstone boson production and decay
2008
This is the summary of the working group on Goldstone Boson Production and Decay of the Chiral Dynamics Workshop in Mainz, September 1–5, 1997. For the production aspects we discuss π0 and η production in nucleon-nucleon collisions and the behaviour of hadrons in various sum rules. For the decays we present a discussion on various K, η and π decay channels. Other aspects discussed are a new treatment of meson-meson scattering, the light-by-light contribution to the muon anomalous magnetic moment and progress in various aspects of the p 6 generating functional in the mesonic sector.
THE X(3872) AND OTHER X,Y,Z RESONANCES AS HIDDEN CHARM MESON-MESON MOLECULES
2011
We report on some ideas concerning the nature of the X(3872) resonance and the need for approximately equal charged and neutral components of $D \bar{D}^* +cc$. Then we discuss how some hidden charm states are obtained from the interaction between vector mesons with charm and can be associated to some of the charmonium-like X,Y,Z states. Finally we discuss how the nature of these states could be investigated through different types of radiative decay.
The hadronic off-shell width of meson resonances
2000
6 páginas, 4 figuras.-- PACS number(s): 12.39.Fe, 12.38.Aw, 12.38.Cy, 12.40.Vv