arXiv subjects

Peter Pauli

Publications and source records attributed to Peter Pauli.

5 recordsLinked to original sources

arXiv2022

The strangeness program at GlueX

The GlueX experiment located at Jefferson Lab studies the spectrum of hadrons using photoproduction on a LH$_2$ target in a wide variety of final states. With its detector system capable of measuring neutral and charged final state particles over almost the full solid angle, and very good particle identification capabilities, GlueX can measure many different hadrons containing strangeness. A linearly polarized photon beam allows the measurement of polarization observables, which contain information about the production mechanisms involved in generating strange particles in photoproduction. In addition, GlueX can perform precise cross-section measurements, which help to study the spectrum of strange hadrons. In this presentation, the GlueX experiment is introduced, and recent progress of its strangeness program is discussed. We present recent results on $Σ^0$ beam asymmetries, $Λ$(1520) spin-density matrix elements and ongoing studies of the $Λ$(1405) lineshape. We also present our recent progress on measurements of $Λ\barΛ$ and $Ξ^{(*)}$ photoproduction. Also, future prospects for strangeness measurements at GlueX are discussed.

hep-ex↗

arXiv2022

Photoproduction of the $Λ$(1520) hyperon with a 9 GeV photon beam at GlueX

The GlueX experiment is located at the Thomas Jefferson National Accelerator Facility (JLab) in Newport News, VA, USA. It features a hermetic 4$π$ detector with excellent tracking and calorimetry capabilities. Its 9 GeV linearly polarized photon beam is produced from the 12 GeV electron beam, delivered by JLab's Continuous Electron Beam Accelerator Facility (CEBAF), via bremsstrahlung on a thin diamond and is incident on a LH2 target. GlueX recently finished its first data taking period and published first results. The main goal of GlueX is to measure gluonic excitations of mesons. These so-called hybrid or exotic mesons are predicted by Quantum Chromodynamics (QCD) but haven't been experimentally confirmed yet. They can have quantum numbers not accessible by ordinary quark-antiquark pairs which helps in identifying them using partial wave analysis techniques. The search for exotic mesons requires a very good understanding of photoproduction processes in a wide range of final states, one of them being $pK^{+}K^{-}$ which contains many meson and baryon reactions. The $Λ$(1520) is a prominent hyperon resonance in this final state and is the subject of this presentation. This talk will give an introduction to the GlueX experiment and show preliminary results for the photoproduction of the $Λ$(1520) hyperon. The measurement of important observables like the photon beam asymmetry and spin-density matrix elements will be discussed and an outlook to possible measurements of further hyperon states in the $pK^{+}K^{-}$ final state will be given.

nucl-ex↗

arXiv2021

Accessing glue through photoproduction measurements at GlueX

Photoproduction experiments are a key tool in the investigation of the spectrum of hadronic states and the way gluons contribute to this spectrum. The GlueX experiment, located at Jefferson Lab, features a linearly polarized tagged photon beam and its detector system is optimized to measure a wide range of neutral and charged final states. GlueX offers unique capabilities to study the spectrum of hadrons and is dedicated to the search for hybrid mesons, states with gluonic degrees of freedom. This talk presents first results from our initial campaign of data taking which finished in 2018.

hep-ex↗

arXiv2021

Strange Hadron Spectroscopy with Secondary KL Beam in Hall D

We propose to create a secondary beam of neutral kaons in Hall D at Jefferson Lab to be used with the GlueX experimental setup for strange hadron spectroscopy. The superior CEBAF electron beam will enable a flux on the order of $1\times 10^4~K_L/sec$, which exceeds the flux of that previously attained at SLAC by three orders of magnitude. The use of a deuteron target will provide first measurements ever with neutral kaons on neutrons. The experiment will measure both differential cross sections and self-analyzed polarizations of the produced $Λ$, $Σ$, $Ξ$, and $Ω$ hyperons using the GlueX detector at the Jefferson Lab Hall D. The measurements will span CM $\cosθ$ from $-0.95$ to 0.95 in the range W = 1490 MeV to 2500 MeV. The new data will significantly constrain the partial wave analyses and reduce model-dependent uncertainties in the extraction of the properties and pole positions of the strange hyperon resonances, and establish the orbitally excited multiplets in the spectra of the $Ξ$ and $Ω$ hyperons. Comparison with the corresponding multiplets in the spectra of the charm and bottom hyperons will provide insight into he accuracy of QCD-based calculations over a large range of masses. The proposed facility will have a defining impact in the strange meson sector through measurements of the final state $Kπ$ system up to 2 GeV invariant mass. This will allow the determination of pole positions and widths of all relevant $K^\ast(Kπ)$ $S$-,$P$-,$D$-,$F$-, and $G$-wave resonances, settle the question of the existence or nonexistence of scalar meson $κ/K_0^\ast(700)$ and improve the constrains on their pole parameters. Subsequently improving our knowledge of the low-lying scalar nonet in general.

nucl-ex↗

arXiv2016

"What's (the) Matter?", A Show on Elementary Particle Physics with 28 Demonstration Experiments

We present the screenplay of a physics show on particle physics, by the Physikshow of Bonn University. The show is addressed at non-physicists aged 14+ and communicates basic concepts of elementary particle physics including the discovery of the Higgs boson in an entertaining fashion. It is also demonstrates a successful outreach activity heavily relying on the university physics students. This paper is addressed at anybody interested in particle physics and/or show physics. This paper is also addressed at fellow physicists working in outreach, maybe the experiments and our choice of simple explanations will be helpful. Furthermore, we are very interested in related activities elsewhere, in particular also demonstration experiments relevant to particle physics, as often little of this work is published. Our show involves 28 live demonstration experiments. These are presented in an extensive appendix, including photos and technical details. The show is set up as a quest, where 2 students from Bonn with the aid of a caretaker travel back in time to understand the fundamental nature of matter. They visit Rutherford and Geiger in Manchester around 1911, who recount their famous experiment on the nucleus and show how particle detectors work. They travel forward in time to meet Lawrence at Berkeley around 1950, teaching them about the how and why of accelerators. Next, they visit Wu at DESY, Hamburg, around 1980, who explains the strong force. They end up in the LHC tunnel at CERN, Geneva, Switzerland in 2012. Two experimentalists tell them about colliders and our heroes watch live as the Higgs boson is produced and decays. The show was presented in English at Oxford University and University College London, as well as Padua University and ICTP Trieste. It was 1st performed in German at the Deutsche Museum, Bonn (5/'14). The show has eleven speaking parts and involves in total 20 people.

physics.pop-ph↗