Bulletin of the American Physical Society
3rd Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Volume 54, Number 10
Tuesday–Saturday, October 13–17, 2009; Waikoloa, Hawaii
Session BD: Hadronic Physics I |
Hide Abstracts |
Chair: A. Hosaka, Osaka University Room: Kohala 4 |
Wednesday, October 14, 2009 7:00PM - 7:15PM |
BD.00001: $\phi$(1020) Photo-production in Neutral Decay Channel $\gamma p \rightarrow p'\phi \rightarrow p'K_S K_L$ Heghine Seraydaryan Using photo-production data on hydrogen target collected with CLAS detector at Thomas Jefferson National Accelerator Facility the $\phi$(1020) meson production cross-sections in the neutral decay channel $\phi \rightarrow K_S K_L$ is obtained for the first time. The measured cross-section shows difference from the charged channel decay ($\phi \rightarrow K_- K_+$). In this talk we present the cross-section and the t - slope for wide photon energy range E= 1.6-3.6 GeV. The spin-density matrix elements were extracted in Helicity and Gottfried-Jackson frames. [Preview Abstract] |
Wednesday, October 14, 2009 7:15PM - 7:30PM |
BD.00002: Photoproduction of the $\phi$ meson on the neutron Anna Micherdzinska, Barry Berman The photoproduction of the $\phi$ meson has attracted a lot of interest in the past decade. Due to the dominant $s\overline{s}$ component in the $\phi$, quark-exchange mechanisms are expected to be strongly suppressed. This makes the photoproduction process an excellent tool to study gluon dynamics in its various manifestations. However, the mechanism of $\phi$ photoproduction on the nucleon is not yet well understood. In order to differentiate between the various mechanisms proposed for $\phi$ photoproduction, data for both differential cross sections and spin observables are needed. All existing experimental data come from $\phi$ photoproduction on the proton, and there is only one published result currently available using a linearly polarized photon beam. There are no experimental results at all for $\phi$ photoproduction on the neutron. Our g13 experiment, using the CLAS at Jefferson Lab, where both linearly and the circularly polarized photons were incident on a deuterium target, can provide such data. We are analyzing these large-kinematic-coverage data to extract both cross sections and angular distributions for the $\gamma + n \rightarrow K^+ K^- + n$ reaction channel. [Preview Abstract] |
Wednesday, October 14, 2009 7:30PM - 7:45PM |
BD.00003: ABSTRACT WITHDRAWN |
Wednesday, October 14, 2009 7:45PM - 8:00PM |
BD.00004: The extraction of $\phi-N$ total cross section from $d(\gamma,pK^+K^-)n$ process Xin Qian In this talk, we will report on the first measurement of the differential cross section of $\phi$-meson photoproduction for the $d(\gamma,pK^{+}K^{-})n$ exclusive reaction channel. The experiment was performed using a tagged-photon beam and the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We carried out a combined analysis to extract the $\phi-N$ total cross section, $\sigma_{\phi N}$, using data from the $d(\gamma,pK^{+}K^{-})n$ channel and those from a previous publication on coherent $\phi$ production on the deuteron. The extracted $\phi-N$ total cross section favors a value above 20 mb. This value is larger than the value extracted using vector-meson dominance models for $\phi$ photoproduction on the proton. [Preview Abstract] |
Wednesday, October 14, 2009 8:00PM - 8:15PM |
BD.00005: $K^{*}$ photoproduction within Regge approach Sho Ozaki, Hideko Nagahiro, Atushi Hosaka Recently strangeness photoproduciton has been of interest in hadron physics. Several photon facilities such as CLAS, LEPS, SAPHIR and CBELSA/TAPS have been providing rich and variety of data. There interesting phenomena are reported including the observation of the pentaquark. Also unexpected peak structures near the threshold are found in $\phi$ photoproduction and in $\Lambda$ resonance photoproduction. In order to understand those interesting phenomena, we have to understand a fundamental mechanism of the open strangeness photoproduction. In this contribution, we study $K^{*}$ photoproduction within Regge approach in a gauge invariant manner. $K^{*}$ is a vector meson like a $\phi$ meson. In $\phi$ photoproduction Pomeron contribution successfully reproduces various cross sections as well as spin observables. Therefore one can expect that Reggeons play an important role also in $K^{*}$ photoproduction. We calculate the energy and $t$ dependence of various cross sections and spin density matrices. We find that the energy dependence differs from that of the $\phi$ photoproduction due to the different trajectories which are allowed in the reactions. In spin density matrices we find that there are obvious differences between our model with Regge phenomenology and the previous work based on the Feynman amplitude of the effective Lagrangian method. [Preview Abstract] |
Wednesday, October 14, 2009 8:15PM - 8:30PM |
BD.00006: Electroproduction of $\pi^0$ and $\eta$ in the resonance region at high $Q^2$ with CLAS Maurizio Ungaro, Kyungseon Joo We report the analysis of exclusive single $\pi^0$ and $\eta$ electroproduction in the resonance region at Jefferson Lab in the $Q^2$ range 2 to 6 $GeV^2/c^2$. A longitudinally polarized $5.75$ $GeV$ electron beam was incident on a 5 cm long liquid Hydrogen target. The CLAS spectrometer at Jefferson Lab was used to detect the final state particles. The goal of this analysis is to extract $\pi^0$ and $\eta$ c.m. differential cross sections over the entire $4\pi$ $c.m.$ solid angle, up to $W=2$ GeV, and their beam spin asymmetries. [Preview Abstract] |
Wednesday, October 14, 2009 8:30PM - 8:45PM |
BD.00007: The Search for Exotic Mesons in $\gamma p\to\pi^+\pi^+\pi^-n$ System in Photoproduction with CLAS Craig Bookwalter In addition to ordinary $q\bar{q}$ pairs, quantum chromodynamics (QCD) permits many other possibilities in meson spectra, such as gluonic hybrids, glueballs, and tetraquarks. Experimental discovery and study of these exotic states provides insight on the nonperturbative regime of QCD. Over the past twenty years, some searches for exotic mesons have met with controversial results, especially those obtained in the three-pion system. Prior theoretical work indicates that in photoproduction one should find gluonic hybrids at significantly enhanced levels compared to that found in pion production. To that end, the CLAS g12 run was recently completed at Jefferson Lab, using a liquid hydrogen target and tagged photons from a 5.71 GeV electron beam. The CLAS experimental apparatus was modified to maximize forward acceptance for peripheral production of mesons. The resulting data contains the world's largest 3$\pi$ photoproduction dataset, with $\gamma p \to \pi^+\pi^+\pi^-n$ events numbering in the millions. Early results describing the data quality, kinematics, and dynamics will be shown. [Preview Abstract] |
Wednesday, October 14, 2009 8:45PM - 9:00PM |
BD.00008: The Neutron electromagnetic Form Factors at Large Momentum Transfer Bogdan Wojtsekhowski, Gordon Cates, Ron Gilman, Brian Quinn, Seamus Riordan Nucleon Form Factors provide powerful constraints on the Generalized Parton Distributions, which form a unified framework for a number of electromagnetic processes. Plans have been developed to measure the neutron electric and magnetic form factors at momentum transfers up to 10 and 18 GeV$^2$, respectively. Experiments will be performed in JLab Hall A after the 12 GeV upgrade of the CEBAF accelerator, using the Super BigBite apparatus. In the talk we will present the proposed experimental setup and projected accuracy of the new measurements. [Preview Abstract] |
Wednesday, October 14, 2009 9:00PM - 9:15PM |
BD.00009: Parity-Violating Asymmetry in the Nucleon to Delta Transition Carissa Capuano The G$^0$ collaboration at Jefferson Lab has measured the
parity-violating asymmetry of polarized electrons scattered
inelastically from the proton. Data were obtained for inclusive
pion electroproduction at a beam energy of 687 MeV, with the
scattered electrons detected at backward angle (${\theta_e}$
${\sim}$ 110$^\circ$). These data will be used to extract the
axial vector transition form factor G$^A_{N\Delta}$ for $Q^2$ in
the range 0.3 GeV/c$^2 |
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