in the double-Regge region Bibrzycki, L; Fernández-Ramírez, C; Mathieu, V ...
The European physical journal. C, Particles and fields,
07/2021, Letnik:
81, Številka:
7
Journal Article
Recenzirano
The production of Formula omitted pairs constitutes one of the golden channels to search for hybrid exotics, with explicit gluonic degrees of freedom. Understanding the dynamics and backgrounds ...associated to Formula omitted production above the resonance region is required to impose additional constraints to the resonance extraction. We consider the reaction Formula omitted measured by COMPASS. We show that the data in Formula omitted can be described by amplitudes based on double-Regge exchanges. The angular distribution of the meson pairs, in particular in the Formula omitted channel, can be attributed to flavor singlet exchanges, suggesting the presence of a large gluon content that couples strongly to the produced mesons.
We calculated the coupled channel photoproduction amplitudes of the scalar
isovector resononace $a_0(980)$, which include the $\pi\eta$, $K^+K^-$ and
$K^0\overline{K^0}$ intermediate states. Based on ...them we obtained the mass
distribution in the $\pi\eta$ channel at photon energy $E_\gamma$=7 GeV,
corresponding to energy accissible in new JLab experiments CLAS12 and GlueX. We
also analyzed the shape of mass distribution as a function of the phase of the
background amplitude.
Tensor meson photoproduction is described as either a direct production process or a consequence of the final state \pi\pi interactions. We calculate the mass distributions for selected partial waves ...and confront our predictions with the measurements of the CLAS experiment. We also point out the structures in the photoproduction amplitudes which may result in observable effects able to indicate the dominant tensor meson photoporduction mechanism.
We study the decay $J/\psi\to\pi^{+}\pi^{-}\pi^{0}$ within the framework of
the Khuri-Treiman equations. We find that the BESIII experimental di-pion mass
distribution in the $\rho(770)$-region is ...well reproduced with a
once-subtracted $P$-wave amplitude. Furthermore, we show that $F$-wave
contributions to the amplitude improve the description of the data in the
$\pi\pi$ mass region around 1.5 GeV. We also present predictions for the
$J/\psi\to\pi^{0}\gamma^{*}$ transition form factor.
Assuming that the $\pi^+\pi^-$ photoproduction at forward angles and high
energies is dominated by one pion exchange we calculate the $\pi^+\pi^-$ mass
distributions for low partial waves. ...Predictions of the model agree well
Assuming that the $\pi^+\pi^-$ photoproduction at forward angles and high
energies is dominated by one pion exchange we calculate the $\pi^+\pi^-$ mass
distributions for low partial waves. Predictions of the model agree well with
the experimental data which indicate that the $S$, $P$ and $D$ waves are
dominated by the $f_0(980)$, $\rho(770)$ and $f_2(1270)$, resonances
respectively.
Results of a new analysis of the K + K- photoproduction at two photon energies, \(E_\gamma = 4 \mbox{GeV}\) and \(5.65 \mbox{GeV}\), with a particular emphasis on the S-wave production are presented. ...We show that the proper treatment of all the helicity components of the S- and P-waves enables one to eliminate the reported discrepancies in the extraction of the S-wave photoproduction cross section from the experimental data.
We calculated the coupled channel photoproduction amplitudes of the scalar isovector resononace \(a_0(980)\), which include the \(\pi\eta\), \(K^+K^-\) and \(K^0\overline{K^0}\) intermediate states. ...Based on them we obtained the mass distribution in the \(\pi\eta\) channel at photon energy \(E_\gamma\)=7 GeV, corresponding to energy accissible in new JLab experiments CLAS12 and GlueX. We also analyzed the shape of mass distribution as a function of the phase of the background amplitude.
PDF
