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lambda. and. sigma. hypernuclei

Description: The present status of structure calculations for p-shell ..lambda.. hypernuclei, including the phenomenological determination of ..lambda..N effective interaction matrix elements, is briefly reviewed. For ..sigma.. hypernuclei the Nijmegen potential model D is used for guidance in constructing ..sigma..N effective interactions. The structure of /sub ..sigma..//sup 12/Be and /sub ..sigma..//sup 12/C, including isospin mixing in the later case, is discussed, and a comparison is made with experimental data. 19 refs., 5 figs., 4 tabs.
Date: January 1, 1985
Creator: Millener, D.J.
Partner: UNT Libraries Government Documents Department

A study of hypernuclei using the (. pi. /sup +/,K/sup +/) reaction

Description: The (..pi../sup plus/,K/sup plus/) reaction was used to study lambda hypernuclear states from /sup 9/Be, /sup 12/C, /sup 13/C, /sup 16/O, /sup 28/Si, /sup 40/Ca, /sup 51/V, and /sup 89/Y 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.
Date: January 1, 1988
Creator: Pile, P.H.
Partner: UNT Libraries Government Documents Department

Neutrino interactions with e/sup +/. mu. /sup -/ and multiple K/sup 0/'s. [Branching ratio]

Description: A scan for directly produced positrons in 5,000 neutrino interactions in the neon (21 percent) hydrogen filled bubble chamber at Fermilab has yielded 15 events, 9 of which have ..mu../sup -/'s identified in the external muon identifier. On correcting for detection efficiency one obtains sigma(e/sup +/..mu../sup -/)/sigma(..mu../sup -/) approximately 1 x 10/sup -2/ for E/sub e/sup +// > .8 GeV and E/sub ..nu../ > 5 GeV. The kaon multiplicity is unexpectedly high. Eleven of the events have one or more Vees and three have two or more. Among the 11 events are two clear ..lambda..'s and two ambiguous K/sup 0//..lambda... There are four events with identifiable charged kaons. A 16th e/sup +/ event (9) is a definite ..nu../sub e/. From this information one concludes that the kaon multiplicity is 2 +- .6 K/sup 0/'s and 2 +- 1 K/sup + -/'s per interaction. From the observation <p/sub ..mu../sup -//>/<p/sub e/sup +//> = 6.6, one concludes that the e/sup +/'s are probably not uniquely from heavy lepton decay. From a variety of analyses involving the e/sup +/ and/or K/sup 0/'s one learns that the mass of the hadron (C) that produces the e/sup +/'s is greater than 1.6 GeV. By determining the fraction of normal charged current (CC) events that have K/sup 0//sub s/ ..-->.. ..pi../sup +/..pi../sup -/ one is able to compare this fraction with the fraction of CC events that have e/sup +/..mu../sup -/ (K/sup 0//sub s/ ..-->.. ..pi../sup +/..pi../sup -/) to establish a conservative lower limit to the semileptonic branching ratio, C ..-->.. (e/sup +/ and ..mu../sup +/) ..nu../C ..-->.. all > 0.33 (1 +- .42), provided that the same number of K/sup 0//sub s/ exists in thenonleptonic decays as in the semileptonic ones, and that the phase space for ..mu../sup +/ and e/sup +/ are nearly equal. ...
Date: July 1, 1976
Creator: Stevenson, M. L.
Partner: UNT Libraries Government Documents Department

Strangeness exchange reactions and hypernuclei

Description: Recent progress in the spectroscopy of ..lambda.. and ..sigma.. hypernuclei is reviewed. Prospects for the production of doubly strange hypernuclei at a future kaon factory are assessed. It is suggested that the (K/sup -/,K/sup +/) reaction on a nuclear target may afford an optimal way of producing the H dibaryon, a stable six quark object with J/sup ..pi../ = O/sup +/, S = -2.
Date: January 1, 1982
Creator: Dover, C.B.
Partner: UNT Libraries Government Documents Department

Strangeness-exchange and strange nuclei

Description: The nuclear strangeness exchange reaction (K/sup -/,..pi../sup -/) is discussed. Possible reaction mechanisms are reviewed, and the spectroscopic ..lambda..-hypernuclear information derived from observation of strangeness exchange is discussed. The more general question of multiply-strange nuclei is introduced. 10 figures, 1 table, 32 references.
Date: January 1, 1978
Creator: Gal, A
Partner: UNT Libraries Government Documents Department

The (. gamma. ,K) program: A new CEBAF initiative for the study of nuclear strangeness

Description: This paper is a summary of the CEBAF working group discussions on electromagnetic production of strangeness in nuclear systems. A review of the recent BNL results in (..pi..,K) is presented as representative of the physics questions that could be addressed with the CEBAF facility. Recommendations of the working group concerning the necessary experimental apparatus for a (e,e',K) program are presented. 13 figs., 2 tabs.
Date: June 1, 1987
Creator: Chrien, R.E. & Hungerford, E.V.
Partner: UNT Libraries Government Documents Department

Recent results from the Mark II detector at SPEAR

Description: Recent results rom the Mark II Detector at SPEAR are presented. These include measurements of the decays tau/sup -/ ..-->.. rho/sup -/..nu../sub tau/ and tau/sup -/ ..-->.. K*/sup -/(890)..nu../sub tau/, observation of direct photons at the psi, inclusive proton and ..lambda.. production and measurements of charmed baryon and charmed meson decays.
Date: November 1, 1979
Creator: Dorfan, Jonathan
Partner: UNT Libraries Government Documents Department

lambda. N effective interaction

Description: A combination of theoretical estimates, based on a ..lambda..N potential model, and phenomenological analysis of hypernuclear data is used to determine a set of four P/sub N/s/sub ..lambda../ two-body matrix elements which characterize the spin dependence of the ..lambda..N interaction in the p shell. The central spin-spin and the ..lambda.. spin-orbit matrix elements are most strongly constrained by existing data. The spin dependence is weak in the sense that s/sub ..lambda../ doublet splittings are predicted to be of order 100 keV except for the special case of /sub ..lambda..//sup 7/Li where the central spin-spin interaction dominates and the ground-state doublet separation is likely to be about 600 keV. The results of recent (K/sup -/, ..pi../sup -/..gamma..) experiments at the Brookhaven AGS are interpreted in terms of the ..lambda..N effective interaction.
Date: May 23, 1984
Creator: Millener, D.J.
Partner: UNT Libraries Government Documents Department