F. J. Klein

ANALYSIS TOOLS FOR NEXT-GENERATION HADRON SPECTROSCOPY EXPERIMENTS

The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopy in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document. The material presented in the article was edited by the following Editorial Board: Marco Battaglieri, Bill J. Briscoe, Su-Urk Chung, Michael Doring, Jozef Dudek, Geoffrey Fox, Christoph Hanhart, Martin Hoferichter, David G. Ireland, Bernhard Ketzer, Bastian Kubis, Vincent Mathieu, Ryan Mitchell, Jose R. Pelaez, Elena Santopinto, Adam Szczepaniak.

Photoproduction of phi Mesons with Linearly Polarized Photons

We propose to measure the reaction gamma(vec) + p --> p + phi with phi --> K^+K^- in the photon energy range of 1.9 < E_gamma < 2.2 GeV by tagging the incident photon energy and detecting the final-state proton in coincidence with the decay K^+ in the CLAS detector. The photons will be produced by coherent bremsstrahlung from a 4 GeV (6 GeV) electron beam incident on a diamond radiator, and will provide an average polarization of 65% (80%) The proposal to build the Coherent Bremsstrahlung Facility has been approved. The reaction can be completely specified by 12 complex density matrix elements composed of 17 independent, real functions of which 11 are measurable. The use of a linearly polarized beam of photons will allow for the extraction of nine of these functions by measuring the angular distributions of the decay kaons for each value of the 4-momentum transfer squared (t). The maximimum value of t is -2.0 (GeV/c)^2 and the experiment will obtain data with good statistics up to

Ray Theory Results and Ray Wavefront Diagrams for the Hyperbolic Cosine Propagation Sound-Speed Profile

In this paper, we provide a complete geometrical treatment of classical rays emanating from an underwater point source and propagating in an unbounded medium where the speed of sound has a hyperbolic cosine dependence on the depth coordinate (z). General results are derived exclusively from Snells law and are not limited to the case in which the ray emitting source is located at a point on the minimum propagation speed plane. Explicit relations are provided for the following: 1) the ray depth coordinate (z) expressed as a function of the ray horizontal range (ρ) and the ray source angle (θ0); 2) all the relations among the ray source angle (θ0), the ray receiver angle (θ), and the travel time (τ) to reach an arbitrary position of the receiver from an arbitrary position of the source; and 3) the classical wavefront coordinates (ρ,z) along a ray expressed as a function of the ray source angle (θ0) and travel time (τ). From the wavefront coordinates (ρ,z), we construct and display ray/wavefront diagrams for a varying source depth (z0) relative to the minimum propagation speed plane. We also derive the time-averaged acoustic energy flux carried along classical ray tubes.

Performance studies of Hamamatsu R9800 photomultiplier tube with a new active base designed for use in the Hall D Broadband tagger Hodoscope

This paper presents the results of a study of a high rate photomultiplier and active base assembly designed for use in scintillator counters of the Hall D Jefferson Lab Broadband fixed-array Tagging Hodoscope. In its standard configuration the fixed-array hodoscope consists of 218 plastic scintillator counters made with Hamamatsu R9800 one inch in diameter photomultiplier tube. All tubes are equipped with designed at JLab new active base. The base comprised of a high voltage divider integrated with amplifiers powered by current flowing through the divider (U.S. Patent No. 6,791,269). This original design allows limiting the PMT anode current to 15-20 μA at a 4 MHz count rate, and allows tube operation at lower high voltage bias voltage while retaining a desired overall gain and dynamic range of output signals. The performance of the PMT assemblies were studied at Jeffeson Lab using a picosecond laser (PLP-10). Subsequently, two hundred fifty PMT and base assemblies were manufactured and tested. The results of testing the R9800 photomultiplier in a new active base are presented and discussed.

Polarization Observables for K{sup +}{Lambda} and K{sup +}{Sigma}{sup 0} Photoproduction form Polarized Protons

The search for undiscovered excited states of the nucleon continues to be a focus of experiments at Jefferson Lab. Recent LQCD calculations have confirmed long-standing quark-model predictions of many more states than have so far been identified.1 A large effort for the N* program has been launched using the CLAS detector to provide the database that will allow nearly model-independent partial wave analyses to be carried out in the search for such states. Polarization observables play a crucial role in this effort, as they are essential in disentangling overlapping resonant and non-resonant amplitudes. In 2010, double-polarization data were taken at JLab using circularly polarized photons incident on a transversely polarized frozen-spin butanol target.2 Our current analysis yields preliminary data of the T and F asymmetries of the K+Λ and K+Σ0 final states, which are compared to predictions of recent multipole analyses. This work is the first of its kind and will significantly broaden the world database for these reactions.

POLARIZATION OBSERVABLES FOR K+Λ AND K+Σ0 PHOTOPRODUCTION FROM POLARIZED PROTONS

The search for undiscovered excited states of the nucleon continues to be a focus of experiments at Jefferson Lab. Recent LQCD calculations have confirmed long-standing quark-model predictions of many more states than have so far been identified.1 A large effort for the N* program has been launched using the CLAS detector to provide the database that will allow nearly model-independent partial wave analyses to be carried out in the search for such states. Polarization observables play a crucial role in this effort, as they are essential in disentangling overlapping resonant and non-resonant amplitudes. In 2010, double-polarization data were taken at JLab using circularly polarized photons incident on a transversely polarized frozen-spin butanol target.2 Our current analysis yields preliminary data of the T and F asymmetries of the K+Λ and K+Σ0 final states, which are compared to predictions of recent multipole analyses. This work is the first of its kind and will significantly broaden the world database for these reactions.

Polarization Observables for Kaon Photoproduction from Polarized Protons

The search for undiscovered excited states of the nucleon continues to be a focus of experiments at Jefferson Lab. Recent LQCD calculations have confirmed long-standing quark-model predictions of many more states than have so far been identified.1 A large effort for the N* program has been launched using the CLAS detector to provide the database that will allow nearly model-independent partial wave analyses to be carried out in the search for such states. Polarization observables play a crucial role in this effort, as they are essential in disentangling overlapping resonant and non-resonant amplitudes. In 2010, double-polarization data were taken at JLab using circularly polarized photons incident on a transversely polarized frozen-spin butanol target.2 Our current analysis yields preliminary data of the T and F asymmetries of the K+Λ and K+Σ0 final states, which are compared to predictions of recent multipole analyses. This work is the first of its kind and will significantly broaden the world database for these reactions.

Polarization Observables for

The search for undiscovered excited states of the nucleon continues to be a focus of experiments at Jefferson Lab. Recent LQCD calculations have confirmed long-standing quark-model predictions of many more states than have so far been identified.1 A large effort for the N* program has been launched using the CLAS detector to provide the database that will allow nearly model-independent partial wave analyses to be carried out in the search for such states. Polarization observables play a crucial role in this effort, as they are essential in disentangling overlapping resonant and non-resonant amplitudes. In 2010, double-polarization data were taken at JLab using circularly polarized photons incident on a transversely polarized frozen-spin butanol target.2 Our current analysis yields preliminary data of the T and F asymmetries of the K+Λ and K+Σ0 final states, which are compared to predictions of recent multipole analyses. This work is the first of its kind and will significantly broaden the world database for these reactions.

K^+ \Lambda

We present a preliminary analysis of the photon beam asymmetry observable (Σ) from the photoproduction reaction channel γn → pπ− in the invariant mass range 1.6–2.3 GeV. The measurement was obtained using the near-4π CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory, USA, employing a linearly polarised photon beam with an energy range 1.1–2.3 GeV, incident on a liquid deuterium target. The measurement will provide new data to address the poorly established neutron excitation spectrum and will greatly expand the sparse world data-set both in energy and angle.