Search results for "Vector meson"
showing 10 items of 116 documents
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…
Low-lying even parity meson resonances and spin-flavor symmetry
2010
A study is presented of the $s-$wave meson-meson interactions involving members of the $\rho-$nonet and of the $\pi-$octet. The starting point is an SU(6) spin-flavor extension of the SU(3) flavor Weinberg-Tomozawa Lagrangian. SU(6) symmetry breaking terms are then included to account for the physical meson masses and decay constants, while preserving partial conservation of the axial current in the light pseudoscalar sector. Next, the $T-$matrix amplitudes are obtained by solving the Bethe Salpeter equation in coupled-channel with the kernel built from the above interactions. The poles found on the first and second Riemann sheets of the amplitudes are identified with their possible Particl…
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.
New interpretation for theDs2*(2573)and the prediction of novel exotic charmed mesons
2010
In this manuscript we study the vector-vector interaction within the hidden-gauge formalism in a coupled channel unitary approach. In the sector $C=1$, $S=1$, $J=2$ we get a pole in the $T$ matrix around 2572 MeV that we identify with the ${D}_{s2}^{*}(2573)$, coupling strongly to the ${D}^{*}{K}^{*}({D}_{s}^{*}\ensuremath{\phi}(\ensuremath{\omega}))$ channels. In addition we obtain resonances in other exotic sectors which have not been studied before such as $C=1$, $S=\ensuremath{-}1$, $C=2$, $S=0$ and $C=2$, $S=1$. These ``flavor-exotic'' states are interpreted as ${D}^{*}{\overline{K}}^{*}$, ${D}^{*}{D}^{*}$, and ${D}_{s}^{*}{D}^{*}$ molecular states but have not been observed yet. In to…
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…
Vector meson-vector meson interaction in a hidden gauge unitary approach
2008
The formalism developed recently to study vector meson-vector meson interaction, and applied to the case of rho rho, is extended to study the interaction of the nonet of vector mesons among themselves. The interaction leads to poles of the scattering matrix corresponding to bound states or resonances. We show that 11 states (either bound or resonant) get dynamically generated in nine strangeness-isospin-spin channels. Five of them can be identified with those reported in the PDG, i.e., the f(0)(1370), f(0)(1710), f(2)(1270), f(2)(')(1525), and K-2(*)(1430). The masses of the latter three tensor states have been used to fine-tune the free parameters of the unitary approach, i.e., the subtrac…
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 …
Hidden gauge formalism for the radiative decays of axial-vector mesons
2009
24 pages, 6 tables, 11 figures.--ISI article identifier:000262979700040 .-- ArXiv pre-print avaible at:http://arxiv.org/abs/0809.0943
Resonances and the Weinberg-Tomozawa 56-baryon-35-meson interaction
2006
Vector meson degrees of freedom are incorporated into the Weinberg-Tomozawa (WT) meson-baryon chiral Lagrangian by using a scheme which relies on spin--flavor SU(6) symmetry. The corresponding Bethe-Salpeter approximation successfully reproduces previous SU(3)--flavor WT results for the lowest-lying s--wave negative parity baryon resonances, and it also provides some information on the dynamics of the heavier ones. Moreover, it also predicts the existence of an isoscalar spin-parity $\frac32^-$ $K^*N$ bound state (strangeness +1) with a mass around 1.7--1.8 GeV, unstable through $K^*$ decay. Neglecting d-wave KN decays, this state turns out to be quite narrow ($\Gamma \le 15$ MeV) and it mi…