The reaction γp→pπ0η has been studied with the CBELSA/TAPS detector at the electron stretcher accelerator ELSA in Bonn for incident photon energies from threshold up to 3.1 GeV. This paper has been ...motivated by the recently claimed observation of a narrow structure in the MNη invariant mass distribution at a mass of 1678MeV/c2. The existence of this structure cannot be confirmed in the present work. Instead, for Eγ = 1400–1500 MeV and the cut Mpπ0≤1190MeV/c2 a statistically significant structure in the Mpη invariant mass distribution near 1700 MeV/c2 is observed with a width of Γ≈35MeV/c2 while the mass resolution is σres = 5 MeV/c2. Increasing the incident photon energy from 1420 to 1540 MeV this structure shifts in mass from ≈ 1700 MeV/c2 to ≈ 1725 MeV/c2; the width increases to about 50 MeV/c2 and decreases thereafter. The cross section associated with this structure reaches a maximum of ≈ 100 nb around Eγ≈ 1490 MeV (W ≈ 1920 MeV), which coincides with the pa0 threshold. Three scenarios are discussed which might be the origin of this structure in the Mpη invariant mass distribution. The most likely interpretation is that it is due to a triangular singularity in the γp→pa0→pπ0η reaction.
The reaction
γ
p
→
p
π
0
η
has been studied with the CBELSA/TAPS detector at the electron stretcher accelerator ELSA in Bonn for incident photon energies from threshold up to 3.1 GeV. This paper has ...been motivated by the recently claimed observation of a narrow structure in the
M
N
η
invariant mass distribution at a mass of
1678
MeV
/
c
2
. The existence of this structure cannot be confirmed in the present work. Instead, for
E
γ
= 1400–1500 MeV and the cut
M
p
π
0
≤
1190
MeV
/
c
2
a statistically significant structure in the
M
p
η
invariant mass distribution near 1700
MeV
/
c
2
is observed with a width of
Γ
≈
35
MeV
/
c
2
while the mass resolution is
σ
res
= 5
MeV
/
c
2
. Increasing the incident photon energy from 1420 to 1540 MeV this structure shifts in mass from
≈
1700
MeV
/
c
2
to
≈
1725
MeV
/
c
2
; the width increases to about 50
MeV
/
c
2
and decreases thereafter. The cross section associated with this structure reaches a maximum of
≈
100 nb around
E
γ
≈
1490 MeV (W
≈
1920 MeV), which coincides with the
p
a
0
threshold. Three scenarios are discussed which might be the origin of this structure in the
M
p
η
invariant mass distribution. The most likely interpretation is that it is due to a triangular singularity in the
γ
p
→
p
a
0
→
p
π
0
η
reaction.
This work presents ideas for the determination of complete experiments using graphs, which are based on a recently published, modified form of Moravcsik's theorem. The lucid representation of ...complete experiments in terms of graphs, which is at the heart of the theorem, leads to a fully automated procedure that can determine complete experiments for in principle any reaction, i.e. for any number of amplitudes \(N\). For larger \(N\) (i.e. \(N \geq 4\)), the sets determined according to Moravcsik's theorem turn out to be slightly overcomplete. A new type of directional graph has been proposed recently, which can decrease the length of the complete sets of observables in some of these cases. The presented results are relevant for reactions with larger numbers of spin-amplitudes, which are at the center of interest in forthcoming measurements, such as single-meson electroproduction \((N=6)\), two-meson photoproduction \((N=8)\) or vector-meson photoproduction \((N=12)\).
We revisit Moravcsik's theorem on the unique extraction of amplitudes from polarization observables, which has been originally published in 1985. The proof is (re-) written in a more formal and ...detailed way and the theorem is corrected for the special case of an odd number of amplitudes (this case was treated incorrectly in the original publication). Moravcsik's theorem, in the modified form, can be applied in principle to the extraction of an arbitrary number of \(N\) helicity amplitudes. The uniqueness theorem is then applied to hadronic reactions involving particles with spin. The most basic example is Pion-Nucleon scattering (\(N=2\)), the first non-trivial example is pseudoscalar meson photoproduction (\(N=4\)) and the most technically involved case treated here is given by pseudoscalar meson electroproduction (\(N=6\)). The application of Moravcsik's theorem to electroproduction yields new results, which for the first time provide insights into the structure and content of complete sets for this particular process. The uniqueness-statements for the various reactions are compared and an attempt is made to recognize general patterns, which emerge under the application of the theorem.
The reaction $\gamma p \rightarrow p \pi^0 \eta$ has been studied with the
CBELSA/TAPS detector at the electron stretcher accelerator ELSA in Bonn for
incident photon energies from threshold up to ...3.1 GeV. This paper has been
motivated by the recently claimed observation of a narrow structure in the
M$_{N\eta}$ invariant mass distribution at a mass of 1678 MeV/$c^2$. The
existence of this structure cannot be confirmed in the present work. Instead,
for E$_{\gamma}$ = 1400 - 1500 MeV and the cut M$_{p\pi^0} \le 1190 $ MeV/$c^2$
a statistically significant structure in the M$_{p\eta}$ invariant mass
distribution near 1700 MeV/$c^2$ is observed with a width of $\Gamma\approx 35$
MeV/$c^2$ while the mass resolution is $\sigma_{res}$ = 5 MeV/$c^2$. Increasing
the incident photon energy from 1420 to 1540 MeV this structure shifts in mass
from $\approx$ 1700MeV/c$^2$ to $\approx$ 1725 MeV/$c^2$; the width increases
to about 50 MeV/$c^2$ and decreases thereafter. The cross section associated
with this structure reaches a maximum of $\approx$ 100 nb around E$_{\gamma}
\approx$ 1490 MeV (W $\approx $ 1920 MeV), which coincides with the $p a_0$
threshold. Three scenarios are discussed which might be the origin of this
structure in the M$_{p\eta}$ invariant mass distribution. The most likely
interpretation is that it is due to a triangular singularity in the $\gamma p
\rightarrow p a_0 \rightarrow p \pi^0 \eta$ reaction
The reaction \(\gamma p \rightarrow p \pi^0 \eta\) has been studied with the CBELSA/TAPS detector at the electron stretcher accelerator ELSA in Bonn for incident photon energies from threshold up to ...3.1 GeV. This paper has been motivated by the recently claimed observation of a narrow structure in the M\(_{N\eta}\) invariant mass distribution at a mass of 1678 MeV/\(c^2\). The existence of this structure cannot be confirmed in the present work. Instead, for E\(_{\gamma}\) = 1400 - 1500 MeV and the cut M\(_{p\pi^0} \le 1190 \) MeV/\(c^2\) a statistically significant structure in the M\(_{p\eta}\) invariant mass distribution near 1700 MeV/\(c^2\) is observed with a width of \(\Gamma\approx 35\) MeV/\(c^2\) while the mass resolution is \(\sigma_{res}\) = 5 MeV/\(c^2\). Increasing the incident photon energy from 1420 to 1540 MeV this structure shifts in mass from \(\approx\) 1700MeV/c\(^2\) to \(\approx\) 1725 MeV/\(c^2\); the width increases to about 50 MeV/\(c^2\) and decreases thereafter. The cross section associated with this structure reaches a maximum of \(\approx\) 100 nb around E\(_{\gamma} \approx\) 1490 MeV (W \(\approx \) 1920 MeV), which coincides with the \(p a_0\) threshold. Three scenarios are discussed which might be the origin of this structure in the M\(_{p\eta}\) invariant mass distribution. The most likely interpretation is that it is due to a triangular singularity in the \(\gamma p \rightarrow p a_0 \rightarrow p \pi^0 \eta\) reaction
Summary
Plant resistance (R) and pathogen avirulence (Avr) gene interactions play a vital role in pathogen resistance. Efficient molecular screening tools for crops lack far behind their model ...organism counterparts, yet they are essential to rapidly identify agriculturally important molecular interactions that trigger host resistance.
Here, we have developed a novel wheat protoplast assay that enables efficient screening of Avr/R interactions at scale. Our assay allows access to the extensive gene pool of phenotypically described R genes because it does not require the overexpression of cloned R genes. It is suitable for multiplexed Avr screening, with interactions tested in pools of up to 50 Avr candidates.
We identified Avr/R‐induced defense genes to create a promoter‐luciferase reporter. Then, we combined this with a dual‐color ratiometric reporter system that normalizes read‐outs accounting for experimental variability and Avr/R‐induced cell death. Moreover, we introduced a self‐replicative plasmid reducing the amount of plasmid used in the assay.
Our assay increases the throughput of Avr candidate screening, accelerating the study of cellular defense signaling and resistance gene identification in wheat. We anticipate that our assay will significantly accelerate Avr identification for many wheat pathogens, leading to improved genome‐guided pathogen surveillance and breeding of disease‐resistant crops.
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