$K^+Λ$(1405) photoproduction at the BGO-OD experiment
Georg Scheluchin, Stefan Alef, Patrick Bauer, Reinhard Beck, Alessandro Braghieri, Philip Cole, Rachele Di Salvo, Daniel Elsner, Alessia Fantini, Oliver Freyerm… 展开作者
Georg Scheluchin, Stefan Alef, Patrick Bauer, Reinhard Beck, Alessandro Braghieri, Philip Cole, Rachele Di Salvo, Daniel Elsner, Alessia Fantini, Oliver Freyermuth, Francesco Ghio, Anatoly Gridnev, Daniel Hammann, Jürgen Hannappel, Thomas Jude, Katrin Kohl, Nikolay Kozlenko, Alexander Lapik, Paolo Levi Sandri, Valery Lisin, Giuseppe Mandaglio, Roberto Messi, Dario Moricciani, Vladimir Nedorezov, Dmitry Novinsky, Paolo Pedroni, Andrei Polonski, Björn-Eric Reitz, Mariia Romaniuk, Hartmut Schmieden, Victorin Sumachev, Viacheslav Tarakanov, Christian Tillmanns
备注：
Contribution to the proceedings of "NSTAR2019: 12th International Workshop on the Physics of Excited Nucleons"
Since the discovery of the $Λ(1405)$, it remains poorly described by conventional constituent quark models, and it is a candidate for having an "exotic" meson-baryon or "penta-quark" structure, similar to states recently reported in the hidden charm sector.
The $Λ(1405)$ can be produced in the reaction $γp \rightarrow K^+Λ(1405)$. The pure I=0 decay mode into $Σ^0π^0$ is prohibited for the mass-overlapping $Σ(1385)$. Combining a large aperture forward magnetic spectrometer and a central BGO crystal calorimeter, the BGO-OD experiment is ideally suited to measure this decay with the $K^+$ in the forward direction. Preliminary results are presented.
*Supported by DFG (PN 388979758, 405882627).
The BGO-OD experiment at the ELSA accelerator facility uses an energy tagged bremstrahlung photon beam to investigate the internal structure of the nucleon. The setup consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. BGO-OD is ideal for investigating low momentum transfer processes due to the acceptance and high momentum resolution at forward angles. This enables the investigation of strangeness photoproduction where $t$-channel exchange mechanisms play a dominant role. A detailed understanding of this low-m…
The BGO-OD experiment at the University of Bonn's ELSA accelerator facility in Germany is ideally suited to investigate photoproduction at extreme forward angles. It combines a highly segmented BGO electromagnetic calorimeter at central angles and an open dipole magnetic spectrometer in the forward direction. This allows the detection of forward going kaons, and complex final states of mixed charge from hyperon decays. Current projects at the BGO-OD experiment include strangeness production of $γp \rightarrow K^+ Λ/Σ^0$ at forward angles, $K^0Σ^0$ with a deuteron target and $K^+Λ(1405)$ line s…
The BGO-OD experiment at the ELSA accelerator facility uses an energy tagged bremsstrahlung photon beam to investigate the excitation structure of the nucleon. The setup consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. BGO-OD is ideal for investigating low momentum transfer processes due to the acceptance and high momentum resolution at forward angles. In particular, this enables the investigation of strangeness photoproduction where t-channel exchange mechanisms play an important role. This also allows acc…
$K^+Λ(1405)$ photoproduction has been studied at the BGOOD experiment via the all neutral decay, $Λ(1405)\rightarrowΣ^0π^0$. The unique BGOOD experimental setup allows both the cross section and $Λ(1405)$ invariant mass distribution (line shape) to be measured over a broad $K^+$ polar angle range, extending to extreme forward $K^+$ angles unattainable at previous experiments. Evidence is provided for the role of a triangle singularity driven by the $N^*(2030)$ resonance, which appears to contribute significantly to $K^+Λ(1405)$ photoproduction. This is observed in both the angular distribution…
$γp \rightarrow K^+ Λ$ differential cross sections and recoil polarisation data from threshold for extremely forward angles are presented. The measurements were performed at the BGOOD experiment at ELSA, utilising the high angular and momentum resolution forward spectrometer for charged particle identification. The data discriminates between conflicting results in the world data set and enable extraction of the cross section as the minimum momentum transfer to the recoiling hyperon is approached.
The GlueX experiment, located in experimental Hall D of Jefferson Lab, seeks to map the spectrum of light mesons in search of exotic hybrid mesons, a predicted class of hadronic states with explicit gluonic degrees of freedom. GlueX is a photoproduction experiment utilizing a linearly polarized photon beam at $E_γ=$ 8-9 GeV and a large acceptance spectrometer. The experiment has already collected orders of magnitude more data than previous experiments at similar energies. We show results on asymmetry measurements in the production of pseudoscalars mesons, which refine our understanding of prod…
The GlueX experiment at Jefferson Lab aims to study the light meson spectrum with an emphasis on the search for hybrid mesons. To this end, a linearly-polarized $9\,$GeV photon beam impinges on a hydrogen target contained within a detector with near-complete neutral and charged particle coverage. In 2018, the experiment completed its first phase of data taking in its design configuration and the quantity of analyzed data already exceed that of previous experiments for polarized photoproduction in this energy regime by orders of magnitude. Polarization observables such as spin-density matrix el…
我们提出了一个搜索的光生的疏轻子玻色子耦合到夸克在GREX实验在杰斐逊实验室。我们详细研究了一个新的规范玻色子耦合到重子数$B$，并估计$γp \to p B$将提供最好的灵敏度为$B$质量超过0.5 GeV。这项研究也将为其他提出的与夸克耦合的暗区态提供灵敏度。最后，我们的研究结果激发了类似的搜索$B$玻色子电生产的CLAS实验。
Perturbative QCD is applied to investigate the near threshold heavy quarkonium photoproduction at large momentum transfer. We take into account the contributions from the leading three-quark Fock states of the nucleon. The dominant contribution comes from the three-quark Fock state with one unit quark orbital angular momentum (OAM) whereas that from zero quark OAM is suppressed at the threshold. From our analysis, we also show that there is no direct connection between the near threshold heavy quarkonium photoproduction and the gluonic gravitational form factors of the nucleon. Based on the co…
