670 Matching Results

Search Results

Advanced search parameters have been applied.

Final technical report, Outstanding Junior Investigator Award for DE-FG02-94ER40869

Description: This report summarizes the research of the Principal Investigator, his postdoctoral research associates, and his students during the period of the award. The majority of the work concerns the behavior of hadrons containing strange, charm, bottom and top quarks, with a particular focus on the extraction of Cabibbo--Kobayashi--Maskawa matrix elements from experiments performed on such systems.
Date: May 16, 2002
Creator: Falk, Adam F.
Partner: UNT Libraries Government Documents Department

Strangeness at SIS energies

Description: In this contribution the authors discuss the physics of strange hadrons in low energy ({approx_equal} 1-2 AGeV) heavy ion collision. In this energy range the relevant strange particle are the kaons and anti-kaons. The most interesting aspect concerning these particles are so called in-medium modifications. They will attempt to review the current status of understanding of these in medium modifications. In addition they briefly discuss other issues related with kaon production, such as the nuclear equation of state and chemical equilibrium.
Date: September 28, 2005
Creator: Koch, Volker
Partner: UNT Libraries Government Documents Department

Strange sea and alpha {sub s} measurements from nu - N deep inelastic scattering at CCFR/NuTeV

Description: We present the latest Next-to-Next-Leading order strong coupling constant, {alpha}{sub s}, extracted from Gross-Llewellyn-Smith sum rule. The value of {alpha}{sub s} from this measurement, at the mass of Z boson, is {alpha}{sub s}{sup NNLO} (M{sup 2}{sub Z}) = 0.114{sup +0.009}{sub -0.012}. We discuss the previous strange sea quark measurement from the CCFR experiment and the prospects for improvements of the measurement in the NuTeV experiment.
Date: August 1, 1998
Creator: Yu, J. & Collaboration, CCFR /NuTeV
Partner: UNT Libraries Government Documents Department

Strangeness production in relativistic nuclear collisions

Description: A review of strange particle production in heavy ion collisions from AGS to SPS energies is presented. Implications of the newest developments in understanding the collision dynamics and the role of strange particle production in the search for a new phase of matter, in both experimental and theoretical sectors, are discussed.
Date: January 1, 1998
Creator: Odyniec, G.J.
Partner: UNT Libraries Government Documents Department

Recent results from E885 -- A search for doubly strange objects

Description: E885, an experiment performed at the Brookhaven National Laboratory Alternate Gradient Synchrotron (BNL AGS) achieved high sensitivity in a search for {Lambda}{Lambda} hypernuclei, {Xi} hypernuclei, and the H particle. Evidence was found for {Xi} hypernuclei. Possible extensions of the methods used are discussed.
Date: October 23, 2000
Partner: UNT Libraries Government Documents Department

Stability of strange quark stars with nuclear crusts against radial oscillations

Description: This paper investigates the stability of the complete sequence of strange-matter stars with nuclear crusts against radial pulsations (acoustical modes). It is found that a broad class of white dwarf- like strange stars is stable against such pulsations. The same holds for the much denser strange stars, which are the strange counter-parts of neutron stars. All stars possessing still higher central densities (e.g., charm stars) turn out to be unstable.
Date: December 5, 1994
Creator: Kettner, Ch.; Weigel, M.K.; Weber, F. & Glendenning, N.K.
Partner: UNT Libraries Government Documents Department

Aspects of strangeness

Description: We review various aspects of strangeness production in relativistic heavy ion collisions from AGS to CERN energies. The experimental data are briefly summarized and various possible theoretical interpretations of these data are evaluated, such as quark-gluon- plasma (QGP), hadron gas (HG) thermal models, or event generators (cascade models). Some comments on the production of strange clusters are offered.
Date: March 1, 1995
Creator: Dover, C.B.
Partner: UNT Libraries Government Documents Department

Strange particle production and s-quark asymmetry

Description: Using hadronic Z{sup 0} decays recorded by the SLD experiment at SLAC, we have studied the production of strange particles as a function of momentum. A high-purity sample of K{sup {+-}} was tagged using Cherenkov Ring Imaging Detector (CRID). The {phi}, {Lambda} and K{sub s} were reconstructed in the K{sup +}K{sup -}, p-{pi} and {pi}{sup +}{pi}{sup -} modes respectively, and CRID identification of K{sup {+-}} and p was used to obtain pure samples of {phi} and {Lambda}. We have used the high electron-beam polarisation delivered by the SLC to measure the left-right forward-backward production asymmetries of these particles, and discuss the relationship of these quantities to the underlying strange quark asymmetry in Z{sup 0} decays.
Date: August 1, 1996
Creator: Narita, S.
Partner: UNT Libraries Government Documents Department

Recent status in the search for the quark-gluon plasma

Description: The author reviews recent experimental results in the search for the quark-gluon plasma. Because the magnitudes of many signals for the plasma are directly proportional to the reaction cross sections, the author examines the corrections to the commonly used lowest-order cross sections. The author finds that the corrections are often significant and should be properly taken into account. The use of dileptons and photons with large transverse momenta is suggested as a means to study the boundary of the quark-gluon plasma.
Date: February 1, 1995
Creator: Wong, Cheuk-Yin
Partner: UNT Libraries Government Documents Department

Chiral Symmetries in Nuclear Physics

Description: The theoretical concepts of a chirally symmetric meson field theory are reviewed and an overview of the most relevant applications in nuclear physics is given. This includes a unified description of the vacuum properties of hadrons, finite nuclei and hot, dense and strange nuclear matter in an extended chiral SU(3){sub L}/SU(3){sub R} {sigma}-{omega} model.
Date: June 12, 2000
Creator: Zschiesche, D.; Papazoglou, P.; Schramm, S.; Beckmann, C.; Schaffner-Bielich, J.; Stocker, H. et al.
Partner: UNT Libraries Government Documents Department

Spin-orbit inversion of excited heavy quark mesons

Description: The mesonic heavy quark spin multiplets with s{sub l}{sup {pi}{sub l}}=(1/2){sup +} and (3/2){sup +} are expected to be the lowest-lying excitations about the pseudoscalar and vector ground states with s{sub l}{sup {pi}{sub l}}=(1/2){sup {minus}}. The author shows that for charm and bottom these multiplets are probably inverted, with the 2{sup +} and 1{sup +} states with s{sub l}{sup {pi}{sup l}}=(3/2){sup +} about 150 MeV below the 1{sup +} and 0{sup +} states with s{sub l}{sup {pi}{sub l}}=(1/2){sup +}. If verified, such an inversion would both support the expectation that confinement has no dynamical spin-dependence and indicate that heavy and light quark systems may be characterized by the same effective low-energy degrees of freedom. As an important byproduct, this work establishes the dynamics of the strange quark as a critical link between heavy- and light-quark hadrons, justifying efforts toward a much more complete experimental and theoretical understanding of strange mesons and baryons and of strangeonia.
Date: June 1, 1997
Creator: Isgur, Nathan
Partner: UNT Libraries Government Documents Department

Search for the H-dibaryon. A proposal to E871

Description: This report consists of vugraphs for a lecture on the search for the H-dibaryon. The physics importance of this search are: (1) low energy test of QCD; (2) new form of matter; (3) missing link between normal hadronic matter and strange matter; (4) astrophysical explanations; and (5) cosmology and dark matter. The author reviews past experiments searching for H-dibaryon. Finally he discusses search methods at E871.
Date: October 1, 1998
Creator: Fitch, V.; Klein, J. & May, M.
Partner: UNT Libraries Government Documents Department

Strange particle production in hadronic Z{sup 0} decays

Description: A study has been made of neutral strange baryons and pseudoscalar mesons produced in hadronic decays of the weak gauge boson V. The experiment was performed at the Stanford Linear Accelerator Center, which has the unique capability of colliding highly polarized electrons with unpolarized positrons. Overall production rates and spectra of the K{sup 0} and the {Lambda}{sup 0} (+{Lambda}{sup 0}) were measured and compared with other experiments as well as with Quantum Chromodynamics calculations. The combination of the small, stable beam spots produced by the SLAC Linear Collider (SLC) and the precision vertexing capabilities of the SLC Large Detector (SLD) permitted the separation of the hadronic events into three quark flavor-enriched samples. An unfolding was performed to obtain flavor-pure samples, and for the first time measurements were made of K{sup 0} and {Lambda}{sup 0} (+{Lambda}{sup 0}) production rates and spectra in uds, c, and b quark events at the Z{sup 0} pole. This measurement revealed significant production differences. Utilizing the large quark production asymmetry due to the polarized electron beam, high-purity quark and antiquark jet samples were obtained. The first measurement of production differences of the {Lambda}{sup 0} baryon in quark and antiquark jets was performed, which provided clear evidence for a leading particle effect at high momenta.
Date: April 1, 1996
Creator: Baird, K.G. III
Partner: UNT Libraries Government Documents Department

Strange Particle Production in $p+p$ Collisions at $\sqrt{s}$= 200GeV

Description: We present strange particle spectra and yields measured atmid-rapidity in sqrt text s=200 GeV proton-proton (p+p) collisions atRHIC. We find that the previously observed universal transverse mass(mathrm mT \equiv\sqrt mathrm p_T 2+\mathrm m2) scaling of hadronproduction in p+p collisions seems to break down at higher \mt and thatthere is a difference in the shape of the \mt spectrum between baryonsand mesons. We observe mid-rapidity anti-baryon to baryon ratios nearunity for Lambda and Xi baryons and no dependence of the ratio ontransverse momentum, indicating that our data do not yet reach thequark-jet dominated region. We show the dependence of the mean transversemomentum (\mpt) on measured charged particle multiplicity and on particlemass and infer that these trends are consistent with gluon-jet dominatedparticle production. The data are compared to previous measurements fromCERN-SPS, ISR and FNAL experiments and to Leading Order (LO) and Next toLeading order (NLO) string fragmentation model predictions. We infer fromthese comparisons that the spectral shapes and particle yields from $p+p$collisions at RHIC energies have large contributions from gluon jetsrather than quark jets.
Date: July 31, 2006
Creator: Abelev, B.I.; Adams, J.; Aggarwal, M.M.; Ahammed, Z.; Amonett,J.; Anderson, B.D. et al.
Partner: UNT Libraries Government Documents Department


Description: Since the earliest days of ultra-relativistic heavy ion physics, there has been interest in strange particle production. Originally, an anomalously large strangeness production was believed to be a signature of the Quark Gluon Plasma. Now the flavor composition of the plasma as reflected in the ratios of abundances of strange and non-strange particles is believed by advocates to tell us the temperature and baryon number density of the Quark Gluon Plasma at decoupling. In addition, there are arguments that suggest that the abundances of strange particles might at intermediate energy or at non-central rapidity, signal the existence of a critical end point of phase transitions in the baryon number chemical potential temperature plane. The purpose of this workshop is to assess the current theoretical and experimental understanding of strangeness production for ultra-relativistic heavy ion collisions.
Date: February 16, 2006
Creator: SAMIOS,N.
Partner: UNT Libraries Government Documents Department

pi+ p Interactions at 250-GeV/c in improved FNAL 30 inch hybrid system

Description: We propose to utilize the excellent momentum resolution, increased angular acceptance, and neutral particle detection capabilities of the improved FNAL 30' hybrid bubble chamber system to study interaction of 250 GeV/c {pi}{sup +} mesons in an enriched {pi}{sup +(l)} beam. We will examine leading particle effects and diffraction dissociation, long and short range correlations, inclusive single particle and resonance production, strange particle production, and systematics of events with forward {pi}{sup 0} and {eta}{sup 0}. Comparison with Experiment 299 results and a proposed experiment at 75 GeV/c will permit determination of general energy dependence of these effects, particularly leading particle cross section where-good resolution near x = 1 is essential to test carefully model dependent predictions of leading particle cross sections.
Date: May 1, 1975
Creator: Bugg, W.M.; Condo, G.T.; Hart, E.L.; Handler, T.; U., /Tennessee; Cohn, H.O. et al.
Partner: UNT Libraries Government Documents Department

Search for anti-neutrino induced muon+ e- events

Description: The authors have examined 1200 interactions with visible energies greater than 7.5 GeV produced by an anti-neutrino beam in the Fermilab 15-foot bubble chamber filled with a light neon hydrogen mixture. They have found one event with a {mu}{sup +}e{sup -} and hadrons in the final state, but with no evidence of strange particle production. This event may be an example of dilepton production by an anti-neutrino interaction, but other interpretations are possible. With 90% confidence, they conclude that the rate for the process {bar {nu}} + N {yields} e{sup -} + {mu}{sup +} + hadrons is {le} .8% of charged current anti-neutrino interactions with visible energy > 7.5 GeV.
Date: April 1, 1976
Creator: Berge, J.F.; DiBianca, F.A.; Hanft, R.; Nezrick, F.A.; Scott, W.G.; Smart, Wesley M. et al.
Partner: UNT Libraries Government Documents Department

A Muon Exposure in the Tohoku High Resolution Bubble Chamber

Description: The authors would like to propose an experiment to investigate muon induced interactions in the Tohoku freon bubble chamber, a high resolution 4{pi} detector. The Tohoku bubble chamber is located in Lab F on the neutrino beam line. The NT test beam line, which passes 4.5 meters east of the bubble chamber, has carried a muon beam to Lab F in the past. it appears possible to bend this beam to the west sufficiently to send muons of approximately 200 GeV to the present position of the Tohoku chamber. A bubble chamber experiment will have better systematics than a comparable muons cattering experiment using counters, but will have lower statistics. With the chamber, direct observation of neutral strange particle and charm particle production will make possible a unique clean study of the virtual photon interactions involved.
Date: January 1, 1986
Creator: Chen, A.; Shapire, A.; Widgoff, M.; U., /Brown; Childress, S.; Murphy, T. et al.
Partner: UNT Libraries Government Documents Department