Download or read book Preliminary Measurement of D sup D Production and D sup Spin Alignment at the Z sup 0 Resonance written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: USING HADRONIC Z[sup 0] DECAYS RECORDED BY THE SLD EXPERIMENT AT SLAC, WE HAVE MEASURED THE VECTOR/(VECTOR+PSEUDOSCALAR) PRODUCTION RATIO, V/(V+ P), FOR THE PROMPT CHARMED MESONS D[sup*+] AND D[sup+]. USING THE CHANNELS D[sup*+][yields] D[sup 0][pi][sup+][sub S], D[sup 0][yields] K[sup -][pi][sup+], AND D[sup 0][yields] K[sup -][pi][sup+][pi][sup -][pi][sup+], AS WELL AS D[sup+][yields] K[sup -][pi][sup+][pi][sup -], WE FIND V/(V+ P)= 0.61+/- 0.09(STAT.)+/- 0.03(BR), WHICH DISFAVORS THE EXPECTATION OF 0.75 FROM NAIVE SPIN COUNTING. WE HAVE ALSO MEASURED THE DEGREE OF D[sup*+] SPIN ALIGNMENT ALONG THE FLIGHT DIRECTION AND FIND IT TO BE CONSISTENT WITH ZERO FOR D[sup*+] FRACTIONAL MOMENTA x= E[sub D*]/E[sub BEAM][gt] 0.2. We compare these results with QCD model predictions.

Download or read book Preliminary Measurement of D sup D Production and D sup Spin Alignment at the Z Resonance written by and published by . This book was released on 1996 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: USING HADRONIC Z° DECAYS RECORDED BY THE SLD EXPERIMENT AT SLAC, WE HAVE MEASURED THE VECTOR/(VECTOR+PSEUDOSCALAR) PRODUCTION RATIO, V/(V + P), FOR THE PROMPT CHARMED MESONS D{sup *+} AND D. USING THE CHANNELS D{sup *+} → D°?+{sub S}, D° → K−?+, AND D° → K−?+?−?+, AS WELL AS D+ → K−?+?−, WE FIND V/(V + P) = 0.61 +/- 0.09(STAT.) +/- 0.03(BR), WHICH DISFAVORS THE EXPECTATION OF 0.75 FROM NAIVE SPIN COUNTING. WE HAVE ALSO MEASURED THE DEGREE OF D{sup *+} SPIN ALIGNMENT ALONG THE FLIGHT DIRECTION AND FIND IT TO BE CONSISTENT WITH ZERO FOR D{sup *+} FRACTIONAL MOMENTA x = E{sub D*}/E{sub BEAM}

Download or read book Preliminary Measurement of D D Production and D Spin Alignment at the Z Resonance written by and published by . This book was released on 1996 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using hadronic Z° decays recorded by the SLD experiment at SLAC, we have measured the vector/(vector+pseudoscalar) production ratio, V/(V+P), for the prompt charmed mesons, D{sup *+} and D. Using the channels D{sup *+}→D°?+{sub s}, D°→ K−?+, and D°→ K{sup - }?+?−?+, as well as D+??2192? K−?+?−, we find V/(V+P) = 0.57 ± 0.07 ({ital stat})± 0.02({ital BR}), which disfavors the expectations of 0.75 from naive spin counting. We have also measured the degree of D{sup *+} spin alignment along the flight direction and find it to be consistent with the zero for D{sup *+} fractional momenta? {triple_bond} E{sub D{sup *}}/D{sub {ital beam}}

Download or read book Preliminary Measurement of Prompt D sup and D sup Meson Production and D sup Spin Alignment in Hadronic Z sup 0 Decays written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors have measured the production rates as a function of scaled energy x of prompt charmed pseudoscalar D[sup[+-]] and vector D*[sup[+-]] mesons in hadronic Z[sup 0] decays. The prompt signal components were isolated from the background of D mesons from B hadron decays using impact parameters of reconstructed D[sup[+-]][yields] K[sup[minus-plus]][pi][sup[+-]][pi][sup[+-]] and D*-daughter D[sup 0][yields] K[sup[minus]][pi][sup+] and D[sup 0][yields] K[sup[minus]][pi][sup+][pi][sup[minus]][pi][sup+] candidates. Using the combined meson production rates the authors have measured the fraction of hadronic Z[sup 0] decays into c[bar c], R[sub c]= 0.182[+-] 0.027 (stat.)[+-] 0.012 (syst.) (Preliminary). Comparison of the D*[sup[+-]] and D[sup[+-]] rates gives a direct probe of vector (V) vs. pseudoscalar (P) meson production for charmed quarks, and for x> 0.4 they have measured P[sub V]= V/(V+ P)= 0.65[+-] 0.09(stat.)[+-] 0.03(syst.)[+-] 0.03 (BR) (Preliminary). They have measured the degree of spin alignment of the D*[sup[+-]] mesons along their flight direction and find it to be consistent with zero. They compared the latter two results with QCD- and model-based predictions of charm-quark jet fragmentation.

Download or read book Preliminary Measurement of Prompt D sup and D sup Meson Production and D sup Spin Alignment in Hadronic Z Decays written by and published by . This book was released on 1997 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors have measured the production rates as a function of scaled energy x of prompt charmed pseudoscalar D{sup ±} and vector D*{sup ±} mesons in hadronic Z° decays. The prompt signal components were isolated from the background of D mesons from B hadron decays using impact parameters of reconstructed D{sup ±} → K{sup {minus_plus}}?{sup ±}?{sup ±} and D*-daughter D° → K−? and D° → K−?+?−?+ candidates. Using the combined meson production rates the authors have measured the fraction of hadronic Z° decays into c{bar c}, R{sub c} = 0.182 {+-} 0.027 (stat.) {+-} 0.012 (syst.) (Preliminary). Comparison of the D*{sup {+-}} and D{sup {+-}} rates gives a direct probe of vector (V) vs. pseudoscalar (P) meson production for charmed quarks, and for x> 0.4 they have measured P{sub V} = V/(V + P) = 0.65 {+-} 0.09(stat.) {+-} 0.03(syst.) {+-} 0.03 (BR) (Preliminary). They have measured the degree of spin alignment of the D*{sup {+-}} mesons along their flight direction and find it to be consistent with zero. They compared the latter two results with QCD- and model-based predictions of charm-quark jet fragmentation.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Preliminary Measurements of Production Of sup plus minus K sup plus minus P K And in Hadronic Z Decays written by and published by . This book was released on 1996 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have measured production of?{sup {+-}},?{sup {+-}}, {ital p}/{ital {bar p}},?° and?°/{bar?}° as a function of momentum in inclusive hadronic {ital Z}° decay events and separately in events containing primary light-({ital uds}) and {ital b}-quarks. The SLD Cherenkov Ring Imaging Detector was used to identify charged pions, kaons, and protons over most of the available momentum range 0.8>{ital p}>33 GeV/c. The neutral?°{sub s} and {Lambda}° were reconstructed using the??− and {ital p}?− decay modes, respectively. We present the first comparisons of momentum of charged tracks measured in the SLD Vertex Detector. Substantial differences are observed, consistent with the kinematics of {ital B}-hadron production in Z° decays and the properties of {ital B}-hadron decays as measured at lower energies.

Download or read book Measurements of Spin sensitive Quantities in Hadronic Decays of Z sup 0 Bosons Produced in E sup e sup minus Annihilations written by and published by . This book was released on 1992 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1992 the SLD experiment at SLAC collected over 11,000 hadronic decay events of Z[sup 0] bosons produced in collisions of polarised electrons with unpolarised positrons delivered by the SLC. Preliminary experimental results are presented on tests of the value of the gluon spin involving events containing three hadronic jets measured in the final state. A leading order QCD prediction is found to be in agreement with the data, whilst a model including scalar gluons is clearly excluded. Effects of the electron beam polarisation upon the orientation of the three-jet event plane are discussed.

Download or read book Preliminary Results for Two Pion Resonances in D sup and D sup sub S r arrow pi sup minus pi sup pi sup from Fermilab Experiment E 791 written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper the authors present preliminary results of a coherent amplitude analysis of three-pion decays of charm mesons. The analysis includes a greater number of possible resonant states than in previous analyses, and produces masses and Breit-Wigner widths of the isoscalar resonances f[sub 0] (980) and f[sub 0] (1370) with better precision than previous measurements. They also present preliminary results for the mass and width of the low lying f[sub o] (400), sometimes called the[sigma] meson.

Download or read book Spin Alignment and Density Matrix Measurement in Sup 28 Si Sup 12 C Orbiting Reaction written by and published by . This book was released on 1990 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gamma-ray angular correlations have been measured for the strongly damped reactions 12C(28Si, 12C)28Si between [theta]{sub cm} = (120° - 160°) for E{sub cm} = 43.5 and 48 MeV. We find that the density matrices for the 12C(21) and 28Si states are almost diagonal with respect to the direction of motion of the outgoing particle. The measured density matrices and spin alignments are consistent with the picture of formation of a long-lived dinuclear complex undergoing orbiting, bending and wriggling motions, but not with those obtained from statistical compound nucleus or sticking model calculations. 17 refs., 2 figs., 1 tab.

Download or read book Precision Electroweak Measurements on the Z Resonance written by Delphi Aleph (L3, Opal, SLD, Collaboration) and published by . This book was released on 2005 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. the data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLD experiment using a polarized beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarized asymmetries. The mass and width of the Z boson, m{sub Z} and {Lambda}{sub Z}, and its couplings to fermions, for example the {rho} parameter and the effective electroweak mixing angle for leptons, are precisely measured: m{sub Z} = 91.1875 {+-} 0.0021 GeV; {Lambda}{sub Z} = 2.4952 {+-} 0.0023 GeV; {rho}{sub {ell}} = 1.0050 {+-} 0.0010; sin{sup 2} {theta}{sub eff}{sup lept} = 0.23153 {+-} 0.00016. The number of light neutrino species is determined to be 2.9840 {+-} 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model. At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its Standard Model expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m{sub t} = 173{sub -10}{sup +13} GeV, and the mass of the W boson, m{sub W} = 80.363 {+-} 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the Standard Model. Using in addition the direct measurements of m{sub t} and m{sub W}, the mass of the as yet unobserved Standard Model Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level.

Download or read book Measurement of Spin Structure Functions at Moderate Q sup 2 Using CLAS written by Volker Burkert and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Spin structure functions of the nucleon in the region of large z and small to moderate Q{sup 2} continue to be of high current interest. Among the topics one can study in this kinematic regime are spin-dependent resonance transition amplitudes and their interference with each other and the non-resonant background, the behavior of the asymmetry A{sub 1} at large x, and the presence or absence of local duality in spin structure functions. The first moment of the spin structure function g{sub 1} goes through a rapid transition from the photon point (Q{sup 2} = 0), where it is constrained by the Gerasimov-Drell-Hearn sum rule, to the deep inelastic limit where it is sensitive to the nucleon spin fraction carried by quarks. This opens up the possibility to study the transition from hadronic to quark degrees of freedom over the whole range of Q{sup 2}. Recently, we concluded a large experimental program to measure these observables with polarized proton and deuteron targets at Jefferson Lab. A highly polarized electron beam, solid polarized NH{sub 3} and ND{sub 3} targets and the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B were used to accumulate over 23 billion events with 4 different beam energies of 1.6, 2.5, 4.2 and 5.7 GeV. We present an overview of the experiment, its kinematic coverage and its statistical power. We show final results from the first run at 2.5 GeV and 4 GeV and preliminary results from the 5.7 GeV and the 1.6 GeV data sets.

Download or read book Measurement of the Deuteron Spin Structure Function G1 sup D x for 1 GeV c 2 Q2 40 GeV c 2 written by and published by . This book was released on 1999 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: New measurements are reported on the deuteron spin structure function g1{sup d}. These results were obtained from deep inelastic scattering of 48.3 GeV electrons on polarized deuterons in the kinematic range 0.01

Download or read book Measurement of A sub B at the Z Resonance Using a Jet charge Technique written by and published by . This book was released on 1997 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present a new preliminary measurement of the parity-violation parameter A{sub b} using a self-calibrating jet-charge technique. In the SLD experiment they observe hadronic decays of Z° bosons produced in collisions between longitudinally polarized electrons and unpolarized positrons a the SLAC Linear Collider. A sample of b{anti b} events is selected using the topologically reconstructed mass of B hadrons. From the 1997--1998 data sample of approximately 200,000 hadronic Z° decays, they obtain A{sub b} = 0.824 " 0.031(stat) " 0.032(syst). Together with the previous 1993--1995 result, it yields a preliminary combined SLD jet-charge measurement of: A{sub b} = 0.849 " 0.026(stat) " 0.031(syst).

Download or read book Measurement of the Proton and Deuteron Spin Structure Functions G2 and Asymmetry A2 written by and published by . This book was released on 1999 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have measured the spin structure functions g2{sup p} and g2{sup d} and the virtual photon asymmetries A2{sup p} and A2{sup d} over the kinematic range 0.02

Download or read book First Measurement of the T Odd Correlation Between The Zeta sup 0 Spin and the Three Jet Plane Orientation in Polarized Zeta sup 0 Decays to Three Jets written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the first measurement of the correlation between the Z[sup 0] spin and the event plane orientation in polarized Z[sup 0] decays into three jets in the SLD experiment at SLAC utilizing a longitudinally polarized electron beam. The CP even and T odd triple product[rvec S][sub Z][center-dot] ([rvec k][sub 1] x[rvec k][sub 2]) formed from the two fastest jet momenta, [rvec k][sub 1] and[rvec k][sub 2], and the Z[sup 0] polarization vector[rvec S][sub Z], is sensitive to physics beyond the Standard Model. We measure the expectation value of this quantity to be consistent with zero and Set 95% C.L. limits of -0.022[lt][beta][lt]0.039 on the correlation.

Download or read book INIS Atomindex written by and published by . This book was released on 1988 with total page 794 pages. Available in PDF, EPUB and Kindle. Book excerpt: