Download or read book Photoproduction Of Lambda And Sigma sup 0 Hyperons Off Protons in the Nucleon Resonance Region Using CLAS at Jefferson Lab written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The differential cross section and hyperon recoil polarizations of the photoproduction of the ground state hyperons, [gamma] p[yields] K[sup+][Lambda] and[gamma] p[yields] K[sup+][Sigma][sup 0], have been measured with the CLAS at Jefferson Lab up to a photon energy in the lab of 2.325 GeV. The results for both channels show significantly larger cross section in the middle to forward angles than have been observed previously by the SAPHIR Collaboration. Both reactions show significantly more backward peaking in the angular distributions than has previously been possible to observe. The backward peaking hints that hyperon resonances in the u-channel play a significant role in the production mechanism. In addition, in the[gamma] p[yields] K[sup+][Lambda] reaction, a previously unobserved bump in the cross section was observed at forward angles, centered on a W of 1.95 GeV with a width of approximately[Gamma]= 100 MeV. In both[gamma] p[yields] K[sup+] Y reactions the recoil polarization in the forward direction seems reasonably well reproduced by t-channel interferences in a Regge model calculation as well as hadrodynamic models that include kaon resonances in the t-channel. The recoil polarization for[gamma] p[yields] K[sup+][Lambda] shows a significant enhancement around a W of 1.9 GeV in the backward angles, which is a sign of resonance activity in this vicinity. The polarization of[gamma] p[yields] K[sup+][Sigma][sup 0] at backward angles is, in contrast, less pronounced and mostly consistent with zero.
Download or read book Photoproduction of Lambda and Sigma Hyperons Off Protons in the Nucleon Resonance Region Using CLAS at Jefferson Lab written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The differential cross section and hyperon recoil polarizations of the photoproduction of the ground state hyperons, [gamma] p 2!K [Lambda] and [gamma] p 2!K [Sigma]°, have been measured with the CLAS at Jefferson Lab up to a photon energy in the lab of 2.325 GeV. The results for both channels show significantly larger cross section in the middle to forward angles than have been observed previously by the SAPHIR Collaboration. Both reactions show significantly more backward peaking in the angular distributions than has previously been possible to observe. The backward peaking hints that hyperon resonances in the u-channel play a significant role in the production mechanism. In addition, in the [gamma] p 2!K+ [Lambda] reaction, a previously unobserved bump in the cross section was observed at forward angles, centered on a W of 1.95 GeV with a width of approximately [Gamma] = 100 MeV. In both [gamma] p 2!K+ Y reactions the recoil polarization in the forward direction seems reasonably well reproduced by t-channel interferences in a Regge model calculation as well as hadrodynamic models that include kaon resonances in the t-channel. The recoil polarization for [gamma] p 2!K+ [Lambda] shows a significant enhancement around a W of 1.9 GeV in the backward angles, which is a sign of resonance activity in this vicinity. The polarization of [gamma] p 2!K+ [Sigma]° at backward angles is, in contrast, less pronounced and mostly consistent with zero.
Download or read book Photoproduction of Lambda and Sigma0 Hyperons Off Protons in the Nucleon Resonance Region Using CLAS at Jefferson Lab written by John W. C. McNabb and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Photoproduction of and 0 Hyperons Off Protons in the Nucleon Resonance Region Using CLAS at Jefferson Lab written by and published by . This book was released on 2002 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: The differential cross section and hyperon recoil polarizations of the photoproduction of the ground state hyperons, ? p → K+ ? and ? p → K+ ?0 , have been measured with the CLAS at Jefferson Lab up to a photon energy in the lab of 2.325 GeV. The results for both channels show significantly larger cross section in the middle to forward angles than have been observed previously by the SAPHIR Collaboration. Both reactions show significantly more backward peaking in the angular distributions than has previously been possible to observe. The backward peaking hints that hyperon resonances in the u-channel play a significant role in the production mechanism. In addition, in the ? p → K+ ? reaction, a previously unobserved bump in the cross section was observed at forward angles, centered on a W of 1.95 GeV with a width of approximately ? = 100 MeV. In both ? p → K+ Y reactions the recoil polarization in the forward direction seems reasonably well reproduced by t-channel interferences in a Regge model calculation as well as hadrodynamic models that include kaon resonances in the t-channel. The recoil polarization for ? p → K+ ? shows a significant enhancement around a W of 1.9 GeV in the backward angles, which is a sign of resonance activity in this vicinity. The polarization of ? p → K+ ?0 at backward angles is, in contrast, less pronounced and mostly consistent with zero.
Download or read book Polarization of Hyperons in Elementary Photoproduction written by Reinhard Schumacher and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent measurements using the CLAS detector at Jefferson Lab of the reactions {gamma} + p {yields} K{sup +} + {Lambda} and {gamma} + p {yields} K{sup +} + {Sigma}{sup 0} have been used to extract the spin transfer coefficients C{sub x} and C{sub z} for the first time. These observables quantify the degree of the photon circular polarization that is transferred to the recoiling hyperons in the scattering plane. The unexpected result is that {Lambda} hyperons are produced '100% polarized' as seen when combining C{sub x} and C{sub z} with the induced transverse polarization, P. Furthermore, C{sub x} and C{sub z} seem to be linearly related. This paper discusses the experimental results and offers a hypothesis which can explain these observations. We show how the produced strange quark can be subject to a pure spin-orbit type of interaction which preserves its state of polarization throughout the hadronization process.
Download or read book Electro and Photoproduction Of omega 783 Mesons Using CLAS at Jefferson Lab written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Electro- and photoproduction of[omega](783) from a proton target have been measured in the CLAS detector at the Thomas Jefferson National Accelerator Facility in Newport News, VA. The photoproduction data were taken over a photon energy range from 0.5 to 2.3 GeV, while the electroproduction data was obtained over a W range of 1.8--2.5 GeV/c[sup 2]. Preliminary acceptance-corrected center-of-mass angular distributions have been examined for both data sets.
Download or read book Measurement of Excited Hyperons in Photoproduction at CLAS written by and published by . This book was released on 2014 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurement results of photoproduced excited hyperon states using the CLAS detector at Jefferson Lab are shown. The invariant mass distribution of the?(1405) has recently been shown to be different for each of the three Sigma pi channels that it decays to, showing that there is prominent interference between the isospin I=0 and I=1 isospin amplitudes. Measurements of the differential and total cross sections of the three hyperons?(1405),?°(1385), and Lambda(1520) are presented and compared. Prospects of future studies using a 12 GeV beam with the GlueX detector are briefly given.
Download or read book Photoproduction of and 0 Hyperons Using Linearly Polarized Photons written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of polarization observables for the reactions $\vec{\gamma} p \rightarrow K+̂ \Lambda$ and $\vec{\gamma} p \rightarrow K+̂ \Sigma0̂$ have been performed. This is part of a programme of measurements designed to study the spectrum of baryon resonances. The accurate measurement of several polarization observables provides tight constraints for phenomenological fits. Beam-recoil observables for the $\vec{\gamma} p \rightarrow K+̂ \Sigma0̂$ reaction have not been reported before now. Furthermore, the measurements were carried out using linearly polarized photon beams and the CLAS detector at the Thomas Jefferson National Accelerator Facility. The energy range of the results is 1.71GeV.
Download or read book Electromagnetic Production of Hyperon Resonances written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of hyperon resonances has entered a new era of precision with advent of high-statistics photoproduction data from the CLAS detector at Jefferson Lab. These data have multi-particle final states, allowing clean identification of exclusive reactions associated with strange mesons and baryons. Examples of physics results are: evidence for isospin interference in the decay of the [Lambda](1405) resonance; a strong suggestion of meson cloud effects in the structure of the [Sigma](1385) resonance; data from K* photoproduction that will test the existence of the purported K0(800)$ meson. Properties of other hyperon resonances will also be studied in the near future.
Download or read book Photoproduction of Multiply Strange Hyperons at CLAS written by and published by . This book was released on 2016 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The activities of the California State University, Dominguez Hills (CSUDH) Hadronic Structure Laboratory, undertaken with the support of the U.S. Department of Energy's Office of Science under grant DE-FG02-07ER41525, are described. This grant was originally awarded in 2007, and then renewed in 2009 and 2012, before it expired in 2015. The work was performed primarily at the home institution on the CSUDH campus in Carson, CA. A significant portion of the work was carried out at the Thomas Jefferson National Accelerator Facility (JLab) in Newport News, VA. The work covered in this award involves the study of the structure of the proton, which is done indirectly by looking at the ? particle. This is a particle with a spin and spatial structure similar to that of the proton, but with a different quark structure. Their properties are expected to be related due to SU(3)F symmetry. Additional work performed under this grant involved the construction of the High Threshold Cherenkov Counter, which was done by CSUDH undergraduate students in collaboration with JLab staff scientists.
Download or read book Sigma Production by Lambda 0 Hyperons written by and published by . This book was released on 1957 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies of Lambda N Interaction Through Polarization Observables for Final state Interactions in Exclusive Lambda Photoproduction Off the Deuteron written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical studies suggest that experimental observables for hyperon production reactions can place stringent constraints on the free parameters of hyperon-nucleon potentials, which are critical for the understanding of hypernuclear matter and neutron stars. Here we present preliminary experimental results for the polarization observables S, Py, Ox, Oz, Cx, and Cz for final-state interactions (FSI) in exclusive L photoproduction off the deuteron. The observables were obtained from data collected during the E06-103 (g13) experiment with the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at Jefferson Lab. The g13 experiment ran with unpolarized deuteron target and circularly- and linearly-polarized photon beams with energies between 0.5 GeV and 2.5 GeV and collected about 51010 events with multiple charged particles in the final state. To select the reaction of interest, the K+ and the L decay products, a proton and a negative pion, were detected in the CLAS. The missing-mass technique was used to identify exclusive hyperon photoproduction events. Final-state interaction events were selected by requesting that the reconstructed neutron has a momentum larger than 200 MeV/c. The large statistics of E06-103 provided statistically meaningful FSI event samples, which allow for the extraction of one- and two-fold differential single- and double-polarization observables. Here we present preliminary results for a set of six observables for photon energies between 0.9 GeV and 2.3 GeV and for several kinematic variables in the Ln center-of-mass frame. Our results are the very first estimates of polarization observables for FSI in hyperon photoproduction and will be used to constrain the free parameters of hyperon-nucleon potentials.
Download or read book Eta Photoproduction from the Proton Using CLAS written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Differential cross sections for the reaction[gamma]p[yields] np have been measured for incident photon energies from 0.75 to 1.95 GeV. Data were taken using the CLAS spectrometer and tagged photon facility at Jefferson Lab. The data provide the first extensive measurements of angular distributions for this process above the S11 (1535) resonance in the range up to W= 2.1 GeV.
Download or read book Hyperon Nucleon Bound States and Electroproduction of Strangeness on He 3 4 written by F. Dohrmann and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The A(e, e'K{sup +})YX reaction has been investigated in Hall C at Jefferson Lab. Data were taken for Q{sup 2} {approx} 0.35 and 0.5 GeV{sup 2} at a beam energy of 3.245 GeV for {sup 3}He, {sup 4}He. The missing mass spectra are fitted with Monte Carlo simulations including {Lambda}, {Sigma}{sup 0}, {Sigma}{sup -} hyperon production. Models for quasifree production are compared to the data, excess yields close to threshold are attributed to FSI. Evidence for {Lambda}-hypernuclear bound states is seen for {sup 3,4}He targets.
Download or read book Photoproduction of the Xi Hyperons written by John Price and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Very little is known about the doubly-strange Xi hyperons. SU(3){sub F} symmetry, based on QCD, implies the existence of many Xi states yet to be found. A complete study of the excited Xi spectrum can also be used to study other related areas of nuclear physics, such as the s - d quark mass difference and Xi p scattering. We will report on a new approach to Xi physics, using the photoproduction process gamma p --> K{sup +} K{sup +} Xi{sup -}, in which the Xi is cleanly tagged by the missing mass of the (K{sup +}K{sup +}) system. We show the current status of this study with the CLAS detector at Jefferson Laboratory, and discuss how it relates to the above topics. We also comment on the future of this program.
Download or read book Eta Photoproduction from the Proton Using CLAS written by Michael Dugger and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Differential cross sections for the reaction {gamma}p {yields} np have been measured for incident photon energies from 0.75 to 1.95 GeV. Data were taken using the CLAS spectrometer and tagged photon facility at Jefferson Lab. The data provide the first extensive measurements of angular distributions for this process above the S11 (1535) resonance in the range up to W = 2.1 GeV.
Download or read book The English Register of Oseney Abbey by Oxford Written about 1460 written by and published by . This book was released on 1907 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
