NOTE: Text or symbols not renderable in plain ASCII are indicated by […]. Abstract is included in .pdf document.
The polarization of [lambda] hyperons in the reaction [lambda] + p […]K[superscript +] + [lambda] has been measured, using the Caltech synchrotron. The measurements were made at 90[degrees] in the c. m. system, at laboratory photon energies of 1100 MeV, 1200 MeV, and 1300 MeV. Protons from the asymmetric decay of the [lambda] were detected by counters placed, symmetrically above and below the plane defined by the photon beam and the mean kaon momentum. Kaons were detected in a 16 to 18 counter range telescope. If preliminary logic was satisfied, all pulse heights from counters in the telescope were digitized and recorded on paper tape, along with relevant coincidence information. A detailed fit to the Bragg curve was made in a digital computer to establish the kaon identification. The results were P[lambda] = +0.34 […] 0.09 at 1100 MeV, + 0.30 […] 0.07 at 1200 MeV, and + 0.08 […] 0.07 at 1300 MeV, where P[lambda] is measured in the […] direction. These data, together with those of other groups, add support to the suggestion that the effects of the third [pi]N resonance are evident in K[lambda] photoproduction.}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {Walker, Robert Lee}, } @phdthesis{10.7907/W7TA-GH83, author = {Daybell, Melvin Drew}, title = {Photoproduction of positive k-mesons in hydrogen at large center of mass angles}, school = {California Institute of Technology}, year = {1962}, doi = {10.7907/W7TA-GH83}, url = {https://resolver.caltech.edu/CaltechTHESIS:07282011-085756389}, abstract = {This is the first of a series of experiments designed to take advantage of the extension of the peak energy of the Caltech electron synchrotron into the 1500 mev region to measure K-photoproduction in hydrogen at energies significantly above threshold. Data on both the γ + p → K^+ + Λ° and the γ + p → K^ + Σ° reactions were obtained for photon energies from 1000 to 1400 mev and center of momentum angles near 125°. At the low energy limit of these measurements agreement is found with earlier measurements in this laboratory and at Cornell. In the 1100 to 1400 mev region the K^+ + Λ° differential production cross section appears to level off at a value of about 1.2 x 10^(-31) cm^2 / steradian or possibly decrease slightly. The three K^+ + Σ° points taken continue the steep rise above threshold observed earlier at Cornell and then appear to drop off above 1250 mev.
The experiment was performed by allowing the K^+ particles produced in a liquid hydrogen target by the incident photon beam to pass through a symmetric wedge magnet, which focused the particles of the proper momentum onto a scintillation counter telescope in which they came to rest. In this way, the momentum, range, and specific ionization loss of each particle passing through the system was determined. To discriminate against the much more numerous pions and protons present, the velocity of each particle was measured by using time of flight techniques.
}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {Sands, Matthew L.}, } @phdthesis{10.7907/JQ7K-E986, author = {Elliott, David Duncan}, title = {Angular Correlation of Photoproduced Pion Pairs}, school = {California Institute of Technology}, year = {1959}, doi = {10.7907/JQ7K-E986}, url = {https://resolver.caltech.edu/CaltechETD:etd-02102006-080252}, abstract = {NOTE: Text or symbols not renderable in plain ASCII are indicated by […]. Abstract is included in .pdf document. The angular correlation between the two pions from the reaction […] has been studied by observing coincidences between two pions produced simultaneously in a hydrogen target in the 1.1 Bev x-ray beam of the Cal Tech synchrotron. The negative pion was detected in a magnetic spectrometer set to accept 150 Mev pions at an angle, […] 35° with respect to the x-ray beams. The positive pion was detected in a counter telescope which was set at various angles, […] with respect to the x-ray beam, and at azimuthal angles, […] with respect to the azimuthal angle of the negative pion, of 0°, 90°, and 180°. For each set of angles the absorbers between the counters of the telescope were chosen such that the observed pairs could be separated into two groups: those produced by photons with energies between 650 and 825 Mev, and those produced by photons with energies from 825 to the bremsstrahlung cut-off energy of 1080 Mev. For pairs produced by photons in the lower energy group the cross section shows no azimuthal dependence in the C. M. system within the statistical error of about […] at either of the two C. M. zenith angles […] = 70° and l20°. For a C. M. azimuthal angle of 180° the cross-section appears to be independent of zenith angle, […] except at the most forward point ([…] = 35°) where the cross-section is about 30% larger than that observed at other angles. The value of the cross section integrated over all […] directions is consistent with a direct measurement of the cross-section for the production of negative pions.}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {Sands, Matthew L.}, } @phdthesis{10.7907/Q2VA-D633, author = {Bloch, Michel A.}, title = {Photoproduction of Pion Pairs in Hydrogen}, school = {California Institute of Technology}, year = {1958}, doi = {10.7907/Q2VA-D633}, url = {https://resolver.caltech.edu/CaltechETD:etd-10072004-094719}, abstract = {NOTE: Text or symbols not renderable in plain ASCII are indicated by […]. Abstract is included in .pdf document. The multiple photoproduction of pions has been observed by detecting, in a magnetic spectrometer, the negative pions which emerged at 60[degrees] and at 120[degrees] from a high-density hydrogen gas target in the bremsstrahlung beam of the electron synchrotron at the California Institute of Technology. The yields of negative pions “per equivalent quantum” were measured for several values of pion energy and bremsstrahlung cut-off energy. From the variations of the yields with bremsstrahlung cut-cuff energy, the cross-section for multiple production of pions was obtained. The cross-section shows no large dependence on the angle of emission of the pion from 90[degrees] to 150[degrees] in the C.M. system. The integral of the cross-section over pion energy is consistent with a constant value […] = 4 x 10[…] cm[…]/ster. for all photon energies between 600 and 1100 Mev. No theoretical prediction is yet available at the photon energies considered in this experiment. The observed dependence of the cross-section on pion energy has been compared to some phenomenological models.}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {Sands, Matthew L.}, }