Download or read book Differential Cross Section and Recoil Polarization Measurements for the Gamma P to K Lambda Reaction Using CLAS at Jefferson Lab written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present measurements of the differential cross section and Lambda recoil polarization for the gamma p to K+ Lambda reaction made using the CLAS detector at Jefferson Lab. These measurements cover the center-of-mass energy range from 1.62 to 2.84 GeV and a wide range of center-of-mass K+ production angles. Independent analyses were performed using the K+ p pi- and K+ p (missing pi - ) final-state topologies; results from these analyses were found to exhibit good agreement. These differential cross section measurements show excellent agreement with previous CLAS and LEPS results and offer increased precision and a 300 MeV increase in energy coverage. The recoil polarization data agree well with previous results and offer a large increase in precision and a 500 MeV extension in energy range. The increased center-of-mass energy range that these data represent will allow for independent study of non-resonant K+ Lambda photoproduction mechanisms at all production angles.
Download or read book Differential Cross Sections and Recoil Polarizations for the Reaction p u2192 K 0 written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, high-statistics measurements of differential cross sections and recoil polarizations for the reaction $\gamma p \rightarrow K+̂ \Sigma0̂$ have been obtained using the CLAS detector at Jefferson Lab. We cover center-of-mass energies ($\sqrt{s}$) from 1.69 to 2.84 GeV, with an extensive coverage in the $K+̂$ production angle. Independent measurements were made using the $K{̂+}p\pi{̂-}$($\gamma$) and $K{̂+}p$($\pi-̂,\gamma$) final-state topologies, and were found to exhibit good agreement. Our differential cross sections show good agreement with earlier CLAS, SAPHIR and LEPS results, while offering better statistical precision and a 300-MeV increase in $\sqrt{s}$ coverage. Above $\sqrt{s} \approx 2.5$ GeV, $t$- and $u$-channel Regge scaling behavior can be seen at forward- and backward-angles, respectively. Our recoil polarization ($P_\Sigma$) measurements represent a substantial increase in kinematic coverage and enhanced precision over previous world data. At forward angles we find that $P_\Sigma$ is of the same magnitude but opposite sign as $P_\Lambda$, in agreement with the static SU(6) quark model prediction of $P_\Sigma \approx -P_\Lambda$. This expectation is violated in some mid- and backward-angle kinematic regimes, where $P_\Sigma$ and $P_\Lambda$ are of similar magnitudes but also have the same signs. In conjunction with several other meson photoproduction results recently published by CLAS, the present data will help constrain the partial wave analyses being performed to search for missing baryon resonances.
Download or read book Differential Cross Sections and Recoil Polarizations for the Reaction math Display written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, high-statistics measurements of differential cross sections and recoil polarizations for the reaction $\gamma p \rightarrow K^+ \Sigma^0$ have been obtained using the CLAS detector at Jefferson Lab. We cover center-of-mass energies ($\sqrt{s}$) from 1.69 to 2.84 GeV, with an extensive coverage in the $K^+$ production angle. Independent measurements were made using the $K^{+}p\pi^{-}$($\gamma$) and $K^{+}p$($\pi^-, \gamma$) final-state topologies, and were found to exhibit good agreement. Our differential cross sections show good agreement with earlier CLAS, SAPHIR and LEPS results, while offering better statistical precision and a 300-MeV increase in $\sqrt{s}$ coverage. Above $\sqrt{s} \approx 2.5$ GeV, $t$- and $u$-channel Regge scaling behavior can be seen at forward- and backward-angles, respectively. Our recoil polarization ($P_\Sigma$) measurements represent a substantial increase in kinematic coverage and enhanced precision over previous world data. At forward angles we find that $P_\Sigma$ is of the same magnitude but opposite sign as $P_\Lambda$, in agreement with the static SU(6) quark model prediction of $P_\Sigma \approx -P_\Lambda$. This expectation is violated in some mid- and backward-angle kinematic regimes, where $P_\Sigma$ and $P_\Lambda$ are of similar magnitudes but also have the same signs. In conjunction with several other meson photoproduction results recently published by CLAS, the present data will help constrain the partial wave analyses being performed to search for missing baryon resonances.
Download or read book Issues in General Physics Research 2011 Edition written by and published by ScholarlyEditions. This book was released on 2012-01-09 with total page 13957 pages. Available in PDF, EPUB and Kindle. Book excerpt: Issues in General Physics Research / 2011 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about General Physics Research. The editors have built Issues in General Physics Research: 2011 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about General Physics Research in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Issues in General Physics Research: 2011 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Download or read book Measurement of Differential Cross Sections and Cx and Cz for Gamma Photon proton Going to Kaon lambda Baryon and Gamma Photon proton Going to Kaon sigma Baryon Using CLAS at Jefferson Lab written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents several observables for the reactions [gamma] p → K+[Lambda] and [gamma] p → K+[Sigma]°. In addition to measuring differential cross sections, we have made first measurements of the double polarization observables Cx and Cz. Cx and C z characterize the transfer of polarization from the incident photon to the produced hyperons. Data were obtained at Jefferson Lab using a circularly polarized photon beam at endpoint energies of 2.4, 2.9, and 3.1 GeV. Events were detected with the CLAS spectrometer. In the [Lambda] channel, the cross sections support the recent observation of new resonant structure at W = 1900 MeV. Studies of the invariant cross section, dsdd show scaling behavior suggesting that the production mechanism becomes t-channel dominated near threshold at forward kaon angles. The double polarization observables show that the recoiling [Lambda] is almost maximally polarized along the direction of the incident photon from mid to forward kaon angles. While [Sigma]o differential cross sections are of the same magnitude as the [Lambda] differential cross sections, there is evidence of different physics dominating the production mechanism. The [Sigma]° invariant cross sections do not show the same t-scaling behavior present in the [Lambda] results. The double polarization observables indicate that the [Sigma]° is not polarized as strongly as the [Lambda]. They also fail to identify one preferred polarization axis. Complete interpretation of these results will rely on model calculations. Currently available isobar models obtain varying degrees of success while attempting to predict the double polarization observables. While the models are in better agreement with the differential cross sections, discrepancies with our cross sections indicate that they must be re-optimized in light of the new data. While the data suggest that a Regge model would provide a good description of K+[Lambda] over most of the range in W, the available Regge calculation overstates the strength of the cross section and does not predict Cx and Cz correctly.
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 Differential Cross Section and Polarization Extractions for Gamma P Going to K sigma0 and Gamma P Going to Phi P Using CLAS at Jefferson Lab Towards a Partial Wave Analysis in Search of Missing Baryon Resonances written by Biplab Dey and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Measurement of the Differential Cross Section for the Reaction gamma N to pi P from Deuterium written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a measurement of the differential cross section for the $\gamma n \to \pi^- p$ process from the CLAS detector at Jefferson Lab in Hall B for photon energies between 1.0 and 3.5 GeV and pion center-of-mass (c.m.) angles ($\theta_{c.m.}$) between 50$^\circ$ and 115$^\circ$. We confirm a previous indication of a broad enhancement around a c.m. energy ($\sqrt{s}$) of 2.2 GeV at $\theta_{c.m.}=90^\circ$ in the scaled differential cross section, $s^7 {\frac{d\sigma}{dt}}$. Our data show the angular dependence of this enhancement as the scaling region is approached in the kinematic region from 70$^\circ$ to 105$^\circ$.
Download or read book Measurement of the Differential Cross Section at 3 4 5 6 GeV c for the Reactions pi sup p Yields K sup 0 lambda sup 0 and pi sup p Yields K sup 0 Sigma sup 0 and of lambda sup 0 Polarization at 5 GeV c written by and published by . This book was released on 1973 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Differential Cross Section and Recoil Polarization from d K0 p written by Nicholas Compton and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A measurement of unpolarized cross sections and polarized cross section differences of deeply virtual compton scattering on the proton at Jefferson Laboratory using Clas written by Nicholas Hirlinger-Saylor and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cette thèse a pour sujet l'étude de la réaction de la Diffusion Compton Profondément Virtuelle (DVCS) sur le proton e + p -> e' + p' + gamma (DVCS). Cette réaction est mesurée en analysant l'expérience e1-dvcs2 qui a eu lieu dans le Hall B du Jefferson Laboratory avec CLAS. La prise de données s'est déroulée du 22 octobre 2008 jusqu'au 23 janvier 2009. Cette analyse a pour but la détermination des sections efficaces non polarisées et les différences de sections efficaces polarisées du DVCS, dans divers bins en xB, Q^2, t et phi. Cette analyse compare les sections efficaces avec plusieurs mesures existantes du DVCS: une analyse parallèle de e1-dvcs2 et une analyse de e1-dvcs1. En factorisant l'élément de matrice qui correspond au DVCS en deux parties, calculables en QCD perturbative et non perturbative, on peut accéder aux Distributions de Partons Généralisées (GPDs) du proton, et ainsi obtenir une vue en 3D des distributions spatiales et en impulsion des quarks et des gluons dans le proton.
Download or read book A Measurement of Unpolarized Cross Sections and Polarized Cross Section Differences of Deeply Virtual Compton Scattering on the Proton at Jefferson Laboratory Using CLAS e1 dvcs2 written by Nicholas A. N. Hirlinger Saylor and published by . This book was released on 2013 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Study of Beam Recoil Polarization Observables for gamma p forward Arrow K0 sigma written by Jose Francisco Gonzalez Ledesma and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The realm of hadronic spectroscopy offers a window into the inner workings of quark-gluon inter- actions within hadrons, while providing new insights into the existence of excited hadrons. The knowledge gained from the further study of baryon resonances are manifold, as they proffer a deeper understanding of strong interactions hitherto unknown and glimpsed only through the properties of the ensuing excited baryon states. Moreover, the study of these excited states is a well-established tool implemented to further understand the non-perturbative (low-energy) regime of Quantum Chromodynamics (QCD). Nonetheless, even after decades of intense theoretical and experimental investigations, most of the predicted excited resonance states proposed by different theoretical programs, including Lattice QCD and Constituent Quark Models (CQM), have yet to be experimentally confirmed. Current theoretical calculations predict a greater number of baryon resonances than what has actually been observed. This disagreement between models and experimental studies in hadronic physics is known as the missing baryon problem. The missing resonances are excited state particles that decay quickly, and might be responsible for filling in the intermediate steps in processes such as [gamma]N → N∗ → YZ. Excited nucleon states are typically found in broadly overlapping (across a wide range of masses and spin-parity combinations Jp̳̳ ) resonances, such as N∗ states (these have the potential to decay into a plethora of final-states YZ composed of baryons and mesons), which can account for the intermediate particle involved in the reaction. Consequently, these states are difficult to isolate via the use of cross-sectional data alone. Therefore, it becomes necessary to introduce a set of polarization observables, as they are an instrumental tool in the disentanglement process of contributing single resonant and non-resonant amplitudes, leading to the identification of the missing baryons. It is theorized that Nucleon (N∗) resonances can decay into final-state pairs like the [lambda]K or K[sigma] channels. The data employed in this thesis was recorded at the Thomas Jefferson National Accelerator Facility (JLab) under the CLAS g12 experiment as part of their N∗ spectroscopy program, via the use of the CEBAF Large Acceptance Spectrometer (CLAS) detector. This experiment recorded photoproduction data from the application of a circularly-polarized photon beam incident on an unpolarized liquid Hydrogen (lH 2 ) target, using a photon energy range of 1.1
Download or read book Photographic Print of Painting Showing the Death of Lincoln written by and published by . This book was released on 1940 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Print in true wood frame with glass.
Download or read book Beam Recoil Polarization Transfer in the Nucleon Resonance Region in the Exclusive vec e p to E K vec Lambda and vec e p to E K vec Sigma 0 Reactions at CLAS written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Beam-recoil transferred polarizations for the exclusive $\vec{e}p \to e'K^+ \vec{\Lambda}, \vec{\Sigma}^0$ reactions have been measured using the CLAS spectrometer at Jefferson Laboratory. New measurements have been completed at beam energies of 4.261 and 5.754~GeV that span a range of momentum transfer $Q^2$ from 0.7 to 5.4~GeV$^2$, invariant energy $W$ from 1.6 to 2.6~GeV, and the full center-of-mass angular range of the $K^+$ meson. These new data add to the existing CLAS $K^+\Lambda$ measurements at 2.567~GeV, and provide the first-ever data for the $K^+\Sigma^0$ channel in electroproduction. Comparisons of the data with several theoretical models are used to study the sensitivity to $s$-channel resonance contributions and the underlying reaction mechanism. Interpretations within two semi-classical partonic models are made to probe the underlying reaction mechanism and the $s\bar{s}$ quark-pair creation dynamics.
