Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userHigh Energy Behaviour of Light Meson Photoproduction
65
0
0.0
(
0
)
Authors
Moskov J. Amaryan
Ask ChatGPT about the research
No Arabic abstract
We evaluated recent CLAS Collaboration measurements for the $90^circ$ meson photoproduction off the nucleon using a tagged photon beam spanning the energy interval $s = 3 - 11$ GeV$^2$. The results are compared with the Quark Counting Rules predictions.
rate research
Read More
In the present talk, we report a recent investigation on photoproduction of the $gamma N to f_0(500)N$ within a framework of the effective Lagrangian. We include the nucleon resonances with pin $1/2$ in the $s$ channel. The coupling constants have been etermined by assuming that the decay process $N^* to (pipi)_{I=0,J=0}N$ can be regarded as $N^* to f_0(500) N$. We discuss the numerical results for the total cross sections and possible extension of the present work.
High-accuracy $Upsilon$-meson photoproduction data from EIC and EicC experiments will allow the measurement of the near-threshold total cross section of the reaction $gamma ptoUpsilon p$, from which the absolute value of the $Upsilon p$ scattering length, $|alpha_{Upsilon p}|$, can be extracted using a Vector-Meson Dominance model. For this evaluation, we used $Upsilon$-meson photoproduction quasi-data from the QCD approach (the production amplitude can be factorized in terms of gluonic generalized parton distributions and the quarkonium distribution amplitude). A comparative analysis of $|alpha_{Upsilon p}|$ with the recently determined scattering lengths for $omega p$, $phi p$, and $J/psi p$ using the A2, CLAS, and GlueX experimental data are performed. The role of the young vector-meson effect is evaluated.
We investigate the reaction mechanism of the $phi$-meson photoproduction off the proton target, i.e., $gamma ptophi p$, up to $sqrt{s}=2.8$ GeV. For this purpose, we employ an effective Lagrangian approach in the tree-level Born approximation, and we employ various experimental and theoretical inputs. As a theoretical setup, the vectorlike Pomeron ($C=+1$) is taken into account as a parameterized two-gluon exchange contribution. We also consider $f_1(1285)$ axial-vector-meson, ($pi,eta$) pseudoscalar-meson, and ($a_0,f_0$) scalar-meson exchanges in the $t$ channel, in addition to the experimentally confirmed nucleon resonances, such as $N^*(2000,5/2^+)$ and $N^*(2300,1/2^+)$, for the direct $phi$-meson radiations in the $s$ and $u$ channels. We provide numerical results for the total and differential cross sections as well as the spin-density matrices in the Gottfried-Jackson, Adair, and helicity frames. We observe that, together with the universally accepted pomeron contribution, the considered meson and nucleon-resonance contributions play significant roles in reproducing the experimental data for the forward and backward $phi$-meson scattering-angle regions, respectively, indicating the nontrivial interferences between mesonic and baryonic contributions.
Enlarging the set of hard exclusive reactions to be studied in the framework of QCD collinear factorization opens new possibilities to access generalized parton distributions (GPDs). We studied the photoproduction of a large invariant mass photon-photon or photon-meson pair in the generalized Bjorken regime which may be accessible both at JLab and at the EIC.
Using the Gribov-Glauber model for photon-nucleus scattering and a generalization of the vector meson dominance model for the hadronic structure of the photon, we make predictions for the cross section of incoherent $rho$ photoproduction in Pb-Pb ultraperipheral collisions (UPCs) in the Large Hadron Collider kinematics. We find that the effect of the inelastic nuclear shadowing is significant and leads to an additional 25% suppression of the incoherent cross section. Comparing our predictions to those of the STARlight Monte Carlo framework, we observe very significant differences.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
