English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We investigate eta photoproduction in the $N^{*}(1535)$ resonance regionwithin the effective Lagrangian approach (ELA), wherein leading contributionsto the amplitude at the tree level are taken into account. These include thenucleon Born terms and the leading $t$-channel vector meson exchanges as thenon-resonant pieces. In addition, we consider five resonance contributions inthe $s$- and $u$- channel; besides the dominant $N^{*}(1535)$, these are:$N^{*}(1440),N^{*}(1520),N^{*}(1650)$ and $N^{*}(1710)$. The amplitudes for the$\pi^\circ$ and the $\eta$ photoproduction near threshold have significantdifferences, even as they share common contributions, such as those of thenucleon Born terms. Among these differences, the contribution to the $\eta$photoproduction of the $s$-channel excitation of the $N^{*}(1535)$ is the mostsignificant. We find the off-shell properties of the spin-3/2 resonances to beimportant in determining the background contributions. Fitting our effectiveamplitude to the available data base allows us to extract the quantity$\sqrt{\chi \Gamma_\eta} A_{1/2}/\Gamma_T$, characteristic of thephotoexcitation of the $N^{*}(1535)$ resonance and its decay into the$\eta$-nucleon channel, of interest to precise tests of hadron models. At thephoton point, we determine it to be $(2.2\pm 0.2)\times 10^{-1} GeV^{-1}$ fromthe old data base, and $(2.2\pm 0.1) \times 10^{-1} GeV^{-1}$ from acombination of old data base and new Bates data. We obtain the helicityamplitude for $N^{*}(1535)\rightarrow \gamma p$ to be $A_{1/2}=(97\pm 7)\times10^{-3} GeV^{-1/2}$ from the old data base, and $A_{1/2}=(97\pm 6)\times10^{-3} GeV^{-1/2}$ from the combination of the old data base and new Batesdata, compared with the results of the analysis of pion photoproductionyielding $74\pm 11$, in the same units.Comment: 43 pages, RevTeX, 9 figures available upon request, to appear in  Phys. Rev.

physical review. d. particles, fields, gravitation, and cosmology/physical review. d. particles and fields

Effective Lagrangian approach to the theory of η photoproduction in the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="italic">N</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">*</mml:mi></mml:mrow></mml:msup></mml:mrow></mml:math>(1535) region

Effective Lagrangian approach to the theory of η photoproduction in theN*(1535) region