Download or read book Spectroscopic Study of Light Lambda Hypernuclei Via the e E K Reaction written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hypernuclear production through the (e, e'K+) reaction makes it possible to realize sub-MeV high-resolution spectroscopy of  hypernuclei thanks to the availability of high quality primary beams. It is in contrast to the (K?, L?) and (L+, K+) reactions which use secondary beams of pions and kaons. Even though hypernuclear cross sections are much smaller than those from meson beams, the (e, e?K+) reaction has advantageous features for  hypernuclear production. A goal of the present study is to further explore and establish (e, e?K+) spectroscopy as a tool to investigate  hypernuclei, succeeding the pioneering experiment JLab E89-009, which was successfully carried out previously. A 1.8 GeV electron beam hit targets at the entrance of the splitter magnet in JLab?s Hall C.A positive kaon and a scattered electron were deflected by the splitter magnet to opposite directions and guided to the high resolution kaon spectrometer (HKS) and the scattered electron spectrometer (Enge), respecti.

Download or read book Spectroscopic Study of the Lambda Hypernuclei by the e e K Reaction written by and published by . This book was released on 2002 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hypernuclear spectroscopy study via the (e,e'K+) reaction has been carried out for the first time, establishing a new technique to study Lambda hypernuclei. The high quality electron beam at Jefferson Lab made it possible to measure Lambda hypernuclear spectra with an energy resolution better than 1 MeV (FWHM). The present experiment was designed to make full use of the virtual photon flux, which peaks at very forward angles, by detecting scattered electrons at 0 degrees. Scattered positive kaons were also detected near 0 degrees, where the cross section of the kaon photo-production is maximized. This unique kinematical configuration was realized with the HyperNuclear Spectrometer System (HNSS), which consisted of the Short-Orbit Spectrometer, the Enge Split-Pole Spectrometer, and the splitter magnet. The $12top{Λ}$B mass spectrum was measured in the 12C(e,e'K+)$12top{Λ}$ reaction with 0.9 MeV (FWHM) energy resolution. The averaged binding energy of the $12top{Λ}$B ground state doublet was obtained to be 11.7 ± 0.1 (statistical) ± 0.3 (systematic) MeV, which is consistent with emulsion data. The general spectral structure of the 12C(e,e'K+) $12top{Λ}$B reaction was found to be similar to that of the 12C(?+,K+)$12top{Λ}$C reaction, showing characteristic peaks corresponding to sLambda and pLambda orbits, as well as a few core-excited states. The cross section of the $12top{Λ}$B ground state doublet was derived to be 117 ± 13 (statistical) ± 14 (systematic) nb/sr. The theoretical prediction of the cross section was consistent with the present result, validating DWIA calculation for hypernuclear yields. The present study proved the effectiveness of the (e,e'K+) reaction for future Lambda hypernuclear spectroscopy studies.

Download or read book Spectroscopic Study of the Lambda Hypernuclei by the e E K Reaction written by Toshinobu Miyoshi and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hypernuclear spectroscopy study via the (e, e'K+) reaction has been carried out for the first time, establishing a new technique to study Lambda hypernuclei. The high quality electron beam at Jefferson Lab made it possible to measure Lambda hypernuclear spectra with an energy resolution better than 1 MeV (FWHM). The present experiment was designed to make full use of the virtual photon flux, which peaks at very forward angles, by detecting scattered electrons at 0 degrees. Scattered positive kaons were also detected near 0 degrees, where the cross section of the kaon photo-production is maximized. This unique kinematical configuration was realized with the HyperNuclear Spectrometer System (HNSS), which consisted of the Short-Orbit Spectrometer, the Enge Split-Pole Spectrometer, and the splitter magnet. The Lambda12B mass spectrum was measured in the 12C(e, e'K+)Lambda12B reaction with 0.9 MeV (FWHM) energy resolution. The averaged binding energy of the Lambda12B ground state doublet was obtained to be 11.7 " 0.1 (statistical) " 0.3 (systematic) MeV, which is consistent with emulsion data. The general spectral structure of the 12C(e, e'K+) Lambda12B reaction was found to be similar to that of the 12C(Lambda+, K+)Lambda12C reaction, showing characteristic peaks corresponding to sLambda and pLambda orbits, as well as a few core-excited states. The cross section of the Lambda12B ground state doublet was derived to be 117 " 13 (statistical) " 14 (systematic) nb/sr. The theoretical prediction of the cross section was consistent with the present result, validating DWIA calculation for hypernuclear yields. The present study proved the effectiveness of the (e, e'K+) reaction for future Lambda hypernuclear spectroscopy studies.

Download or read book Spectroscopic Research of Lambda Hypernuclei Up to Medium heavy Mass Region with the e E K Reaction written by and published by . This book was released on 2014 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 2009 (August-November), the E05-115 experiment was carried out at JLab to investigate L hypernuclei in the wide mass region up to A = 52 ($7\atop{{u039B}}$He, $10\atop{{u039B}}$Be, $12\atop{{u039B}}$B and $52\atop{{u039B}}$V) with the (e, e'K+) reaction. This is the first attempt to investigate a medium heavy L hypernucleus with the (e, e'K+) reaction. Experimentally, it is difficult to measure heavier L hypernuclei as background rates of particles which originate from electromagnetic processes are roughly in proportion to Z2 (Z: target proton number) in the (e, e'K+) experiment. To perform the experiment, many experimental techniques have been developed and introduced such as optimization of the electron spectrometer configuration (tilt method), clean kaon identification, particle tracking under high multiplicity environment, precise energy scale calibration and so on. In the present thesis, experimental results of the elementary process of p(e, e'K+)L, L hypernuclei of $7\atop{{u039B}}$He, $10\atop{{u039B}}$Be, $12\atop{{u039B}}$B and $52\atop{{u039B}}$V are shown. Elementary processes of the electroproduction of L and [Sigma]0, p(e, e'K+)L, [Sigma]0 were used for the absolute energy scale calibration of our spectrometer systems. A careful Monte Carlo simulation shows that the binding energy can be obtained with a systematic error of 0.11 MeV with our energy scale calibration method. A study of the elementary process of L is important to understand L hypernuclei as it is essential for theoretical calculations of L hypernuclei. The differential cross section of the p(e, e'K+)L reaction at the small K+ scattering angle (theta-CM/gamma-K approx. 15.5°), the small Q2 (approx 0.01 [GeV/c]2) and the total energy of W = 1.92 GeV, where no experimental data exists was obtained to be 235 ± 13$+28\atop{-24}$ nb/sr. The ground state (1/2+) binding energy of $7\atop{[Lambda]}$He was already measured in JLab E01-011 (2005). In the present work, the binding energy of 1/2+ state was determined to be B[Lambda] = 5.55 ± 0.10 ±0.11 MeV with five times more statistic and smaller systematic errors than those of the previous experiment. The ground state binding energy is important to test the phe- nomenologically introduced CSB (Charge Symmetry Breaking) LN interaction for A = 7, T = 1 hypernuclear systems. In addition, a peak which is interpreted as 3/2+ and 5/2+ states was measured to be B[Lambda] = 3.65 ± 0.20 ±0.11 MeV with sufficient statistic for the first time. Only three events of the ground state of $10\atop{[Lambda]}$ Be had been observed in the emulsion experiments. The present experiment is the first spectroscopic measurement of 10/L-Be, and the detailed structures have been successfully measured for the first time. About three times better energy resolution was achieved in the present experiment (0.78 MeV in FWHM) than that of the mirror L hy- pernucleus, $10\atop{[Lambda]}$B (2.2 MeV in FWHM) which was measured in the ([pi]+, K+) experiment at KEK. The result of the ground state binding energy was obtained to be B[Lambda] = 8.55 ± 0.07 ± 0.11 MeV which serves also to discuss about the CSB effect in the LN interaction. $12\atop{[Lambda]}$B has been measured with the world best energy resolution of 0:5 MeV (FWHM) among the reaction spectroscopy of L hypernuclei. The results of $12\atop{[Lambda]}$B are compared with the experimental results in the previous experiments to confirm the consistency. Furthermore, the obtained ground state binding energies of $12\atop{[Lambda]}$B (B[Lambda]= 11.38 ± 0.02 ± 0.11 MeV) and $52\atop{[Lambda]}$V (B[Lambda] = 21.88 ± 0.59 ± 0.11 MeV) indicate that the reported value of 12/L-C which has been used as a reference of binding energy measurements for the ([pi]+, K+) experiments would be shallower by ~ 0.5 MeV. A pilot study for investigation in the medium-heavy mass region with the (e, e'K

Download or read book Spectroscopy of Medium heavy Lambda Hypernuclei Via the pi Kappa Reaction written by Dideaki Hotchi and published by . This book was released on 2000 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of High precision Lambda Hypernuclear Spectroscopy Via the e E K Reaction written by and published by . This book was released on 2011 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of [Lambda] hypernuclear structure is very interesting in point of the understanding of the interaction between [Lambda] and nucleon ([Lambda]-N interaction) and its strange structure itself due to the containment of a [Lambda] hyperon which has a strangeness as a new degree of freedom. In the several way to study the Lamda hypernuclei, the (e, e'K+) reaction spectroscopy is a powerful tool for the precise investigation of [Lambda] hypernuclear structure. The purpose of the preset thesis is the establishment of the experimental design with the efficient data analysis method for the (e, e'K+) hypernuclear spectroscopic experiment in the wide mass region (from A=7 to A=52). It is very challenging to perform the (e, e'K+) spectroscopic experiment with such a heavy target, because of the huge electron background due to the bremsstrahlung process. In the experiment, it is required to obtain the necessary hypernuclear yield, suppressing the background event ratio. We achieved these requirements by newly constructing the high resolution electron spectrometer (HES) and splitter magnet (SPL) dedicated to the (e, e'K+) spectroscopic experiment. The HES consists of two quadrupole magnets and a dipole magnets (Q-Q-D) with a momentum resolution of dp/p = 3x10-4 at p = 0.84 GeV/c. It was used being vertically tilted by 6.5 degree so as to optimize signal to noise ratio and hypernuclear yield. The SPL is a dipole magnet. The experimental target was placed at the entrance of this magnet. The role of the SPL is to separate four kind of particles; scattered kaons, photons created by the bremsstrahlung, the post beam and scattered electrons. In addition, since the SPL is a part of the kaon and electron spectrometers. We designed the magnet shape carefully considering these points. The experiment was performed with 2.344 GeV/c electron beam from CEBAF at Jefferson Lab. The experimental setup consists of the HES, SPL and HKS (high momentum resolution kaon spectrometer). The HKS is also a Q-Q-D type spectrometer with the momentum resolution of dp/p = 2x10-4 at p = 1.2 GeV/c. In the data analysis, the particle momentum calibration was the most important procedure. At the initial point, the particle momentum was obtained from the calculated magnetic field map of the spectrometer whose accuracy is an order of 10-2. The initial momentum was calibrated by two step, the the magnetic field map improvement and the calibration with known masses of [Lambda]/[sigma]0 which were observed by the CH2 target data. As a result of the calibration, the momentum resolutions of HKS and HES were estimated as 4x10-4 and 6x10-4, respectively. Though these values are the double of the designed value, it was achieved to obtain the [Lambda]/[sigma]0 peaks with the same order of the designed energy from the original calculated magnetic field. The cross section was calculated with the several estimated factors. The averaged p([gamma]*, K+)[Lambda] cross section in the HKS acceptance, (0.90

Download or read book Hypernuclear Spectroscopy Using the e E K Reaction written by and published by . This book was released on 2006 with total page 44607 pages. Available in PDF, EPUB and Kindle. Book excerpt: A pioneering experiment in Lambda hypernuclear spectroscopy, undertaken at the Thomas Jefferson National Accelerator Facility (Jlab), was recently reported. The experiment used the high- precision, continuous electron beam at Jlab, and a special arrangement of spectrometer magnets to measure the spectrum from {nat}C and 7Li targets using the (e, e' K+)reaction. The 12B hypernuclear spectrum was previously published. This experiment is now reported in more detail, with improved results for the 12B hypernuclear spectrum. In addition, unpublished results of the 7He hypernuclear spectrum are also shown. This later spectrum indicates the need for a more detailed few-body calculation of the hypernucleus and the reaction process. The success of this experiment demonstrates that the (e, e'K+) reaction can be effectively used as a high resolution tool to study hypernuclear spectra, ant its use should be vigorously pursued.

Download or read book Spectroscopic Investigation of P Shell Lambda Hypernuclei by the e E K Reaction written by and published by . This book was released on 2014 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hypernuclear spectroscopy is a powerful tool to investigate Lambda-N interaction. Compared with other Lambda hypernuclei productions, electroproduction via the (e, e'K+) reaction has the advantage of exciting states deeply inside of the hypernucleus and achieving sub-MeV energy resolution. The E05-115 experiment, which was successfully performed in 2009, is the third generation hypernuclear experiment in JLab Hall C.A new splitter magnet and electron spectrometer were installed, and beam energy of 2.344 GeV was selected in this experiment. These new features gave better field uniformity, optics quality and made the tilt method more effective in improving yield-to-background ratio. The magnetic optics of the spectrometers were carefully studied with GEANT simulation, and corrections were applied to compensate for the fringe field cross talk between the compact spectrometer magnets. The non-linear least chi-squared method was used to further calibrate the spectrometer with the events from Lambda, Sigma0 and B12Lambda and uniform magnetic optics as well as precise kinematics were achieved. Several p-shell Lambda hypernuclear spectra, including B12[Lambda], Be10[Lambda], He7[Lambda], were obtained with high energy resolution and good accuracy. For B12[Lambda], eight peaks were recognized with the resolution of ~540keV (FWHM), and the ground state binding energy was obtained as 11.529 ± 0.012(stat.) ± 0.110(syst.) MeV. Be10[Lambda], twelve peaks were recognized with the resolution of ~520keV (FWHM), and the binding energy of the ground state was determined as 8.710 ± 0.059(stat.) ± 0.114(syst.) MeV. For He7[Lambda], three peaks were recognized with the resolution of ~730keV, and the ground state binding energy was obtained as 5.510 ± 0.050(stat.) ± 0.120(syst.) MeV. Compared with the published data of B12[Lambda] from the JLab Hall A experiment, four extra peaks were fitted and interpreted thanks to the highest ever energy resolution and sufficient statistics. The determined binding energy of Be10[Lambda] provides new information on charge symmetry breaking effect in the Lambda-N interaction. Compared with the results of He7Lambda from the E01-011 experiment, the ground state position is consistent with 4 times more statistics, and two extra peaks corresponding to excited states were recognized.

Download or read book Spectroscopic Study of Lambda Hypernuclei Beyon the P Shell written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hypernuclear Spectroscopy of 12lambdaB by the e E K Reactions written by Joerg Reinhold and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The first Lambda-hypernuclear spectroscopy study using an electron beam has been carried out at Jefferson Lab. The hypernuclear spectrometer system (HNSS) was used to measure spectra from the 12C (e, e'K+) 12Lambda B reaction with close to 1 MeV resolution, the best energy resolution obtained so far in hypernuclear spectroscopy with magnetic spectrometers. This paper describes the HNSS and preliminary results for the 12Lambda B system. A program of hypernuclear physics experiments is planned for the future with much higher yield and even better energy resolution.

Download or read book Spectroscopy of Electroproduced Light to Medium Mass Lambda Hypernuclei written by and published by . This book was released on 2010 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the main tasks of nuclear physics is the study of subatomic particles and their interactions. Nowadays, the fundamental theory of strong interactions is a particularly interesting subject in the field. At the current moment, such a theory is not complete yet. It describes very well the nucleon-nucleon (NN) interactions, which were intensively studied over the last several decades. In our modern, technically advanced world the research gravitates towards the higher energies, reaching deeper inside of the nuclear structure. About sixty years ago the strong interaction was associated with the interaction between nucleons responsible for holding those nucleons together within the nuclear volume. However, with discovery of mesons and strange particles, the picture has changed. The proof of bound states of strange baryons (? particles) with nucleons revealed a broad class of particles participating in the strong interaction, called hadrons. The rich variety of hadron interactions raises an important topic in modern nuclear physics which strives for providing a deep insight into nuclear matter structure. The analysis of the interaction of a strange baryon, called a hyperon, with a nucleon delivers new knowledge of nuclear properties, which were not understood with widely studied nucleon-nucleon interactions. The direct approach for creating an interaction of free hyperons with nucleons in the target is not an easy task in experimental nuclear physics. The relatively short lifetime of free hyperons, which can only be produced as a secondary beam, leads to extremely low statistics. Nowadays, the best known method of hyperon-nucleon interaction study is the formation of hyperons inside of the nucleus. The bound hyperon serves as a probe of nuclear properties of such complex nuclear systems called hypernuclei. Hypernuclear physics itself is a sub-area of nuclear physics, which studies such bound systems. It employs the rich knowledge of the nucleon-nucleon interaction and at the same time performs a generalization of the above mentioned interaction for systems with a third quark flavor – strangeness [1]. Production reactions of ? particles and hypernuclei, as well as spectroscopy and decay modes, provide valuable information on the hyperon interaction. For example, analysis of ? and hypernuclear decay modes gives knowledge of the properties of weak interactions. The study of the energy of ground and excited states exposes the laws of baryon distribution inside of the nucleus. Investigation of ?N and ?? potentials is important for baryon-baryon theories that include strange quarks, e.g. SU(3). These potentials are more short-ranged than the ones for NN and therefore the additional degrees of freedom play an essential role.

Download or read book Spectroscopic Study of Capital Lambda hypernuclei Beyond the P shell written by Victor Manuel Rodriguez and published by . This book was released on 2006 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electron Induced Hypernuclear Spectroscopy Results in Hall A at Jefferson Lab written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The characteristics of the Jefferson LAB electron beam, together with those of the experimental equipments, offer a unique opportunity to study hypernuclear spectroscopy via electromagnetic induced reactions. Results are presented on 12C, 16O and 9Be targets. In the hypernuclear missing-mass spectrum the experiment achieves sub-MeV energy resolution by exploiting the characteristics of the High Resolution Spectrometer pair and the beam quality available at JLab. These studies have provided, among other things, the first quantitative information on core-excited states in hypernuclei, as well as the precise determination of Lambda binding energy in the Lambda16N hypernucleus. For the experiment on oxygen, a waterfall target has been employed, allowing simultaneous measurement of the elementary reaction on protons: a crucial measurement to disentangle the contribution of the elementary reaction from the measured hypernuclear production cross section, yielding direct access to the nucleus-hypernucleus transition structure.

Download or read book A Study of Hypernuclei Using the Pi K Reaction written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The (.pi./sup plus/, K/sup plus/) reaction was used to study lambda hypernuclear states from 9Be, 12C, 13C, 16O, 28Si, 4°Ca, 51V, and 89Y targets. Ground state excitations were seen for all targets as well as clear indications for the .lambda. populating bound shell model single-particle states. The data will be compared with DWBA calculations of Dover and Millener. 10 refs., 2 figs., 1 tab.

Download or read book The Production and Decay of Hypernuclei written by and published by . This book was released on 1990 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hypernuclei have been studied for the last 35 years using several techniques. Since 1970, the {sup A}Z (K−, [pi]−) {sub {Lambda}}{sup A}Z strangeness-exchange reaction has been used at CERN, BNL, and KEK to produce hypernuclei and study their spectroscopic properties. These studies also include experiments where decay gamma rays and hypernuclear weak decay products are detected in coincidence with hypernuclear production. Recent experiments at BNL and KEK have proven the utility of the {sup A}Z ([pi], K) {sub {Lambda}}{sup A}Z reaction to study hypernuclear spectroscopy. Although I have no hope of covering this field in much detail, I write this paper as an introduction to the subject and highlights some of the recent experimental developments. 37 refs., 6 figs., 2 tabs.

Download or read book First Experiment on Spectroscopy of Lambda Hypernuclei by Electroproduction at Jlab written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The first experiment in Lambda-hypernuclear spectroscopy using the high precision electron beam at Jefferson laboratory (Jlab) has been carried out. The hypernuclear spectrometer system (HNSS) was used to measure spectra from the 12C(e, e(prime)K)12{sub {Lambda}}B reaction with sub-1 MeV resolution, the best energy resolution obtained thus far in hypernuclear spectroscopy with magnetic spectrometers. This paper describes the HNSS and the preliminary results for the 12{sub {Lambda}}B system. The experimental spectrum is consistent with the expected strong spin-flip excitations of unnatural parity states. A program of hypernuclear physics experiments is planned for the future with much higher yield and even better energy resolution.

Download or read book Spectroscopy of 28Al Lambda 12B Lambda 7He Lambda by the e e K Reaction written by and published by . This book was released on 2009 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hypernuclear spectroscopy by the $(e,e{̂\prime}K+̂)$ reaction is one of the powerful tools to investigate precise structures of hypernuclei and to study $\Lambda$N interaction. The second generation hypernuclear experiment at JLab Hall C(E01-011) was successfully performed in 2005, introducing the two novel experimental configurations, High resolution and large acceptance Kaon Spectrometer(HKS) and Tilt method. Thanks to these new configurations, various hypernuclei such as ${̂28}_{\Lambda}$Al, $_̂{\Lambda}$B and ${̂7}_{\Lambda}$He were measured with precise energy resolution of 500 keV (FWHM). Obtained absolute binding energies and cross sections were compared with other experimental data and recent theoretical calculations based on shell model and cluster model. The results of this study provided new information on $\Lambda$N interaction.