Analyzing powers ( A y ) and spin-rotation-depolarization parameters ( D SS , D SL , D LS , D LL , D NN ) were determined for 500 MeV p + 2 H and p + 12 C inclusive quasielastic scattering at 10°, 15°, and 20° laboratory scattering angles. The p + 2 H data are consistent with the isospin-average of the proton-proton and proton-neutron scattering observables; the p + 12 C data are not. A relativistic plane wave impulse approximation calculation leads to better agreement with the p + 12 C spin-observables.
Inclusive quasielastic p deut measurements.
Inclusive quasielastic p c measurements.
A complete set of polarization-transfer observables has been measured for quasifree (p→,n→) reactions on H2, C12, and Ca40 at a bombarding energy of 495 MeV and a laboratory scattering angle of 18°. The data span an energy-loss range from 0 to 160 MeV, with a corresponding momentum transfer range of qc.m.=1.7–1.9 fm−1. The laboratory observables are used to construct partial cross sections proportional to the nonspin response and three orthogonal spin responses. These results are compared to the transverse spin response measured in deep inelastic electron scattering and to nuclear responses based on the random phase approximation. The polarization observables for all three targets are remarkably similar and reveal no evidence for an enhancement of the spin-longitudinal nuclear response relative to the spin-transverse response. These results suggest the need for substantial modifications to the standard form assumed for the residual particle-hole interaction.
No description provided.
No description provided.
No description provided.
The energy spectra of deuterons recoiling from a deuterium gas target bombarded by transversely polarized 796-MeV protons have been measured to obtain the differential cross sections, dσdt, and analyzing powers, Ay(t), for p→-d elastic scattering over a range of laboratory angles from 4.53° to 13.02°, corresponding to a range of four-momentum transfer squared, |t|, from 0.013 to 0.108 GeV2/c2. Employing several sets of nucleon-nucleon, N-N, amplitudes obtained from N-N phase shift analyses, comparisons are made between the experimental data and the predictions of a multiple scattering theory. In this region of four-momentum transfer, Ay is shown to depend almost entirely on the spin-independent and spin-orbit N-N amplitudes. NUCLEAR REACTIONS d(p→, p)d, E=796 MeV; measured dσdt(θ) and Ay(θ); comparison with multiple-scattering theory using free N-N amplitudes, −t=0.013−0.108 GeV2/c2, Δt=1.88×10−3 GeV2/c2.
X ERROR D(-T) = 0.0019 GEV**2.
500 MeV p→+p elastic and quasielastic, and p→+n quasielastic, analyzing powers (Ay) and spin-rotation-depolarization parameters (DSS, DSL, DLS, DLL, DNN) were determined for center-of-momentum angular ranges 6.8°–55.4° (elastic) and 22.4°–55.4° (quasielastic); liquid hydrogen and deuterium targets were used. The p→+p elastic and quasielastic results are in good agreement; both the p→+p and p→+n parameters are well described by current phase shift solutions.
The elastic P P analysing power at 500 MeV incident proton energy. There is an additional overall normalization uncertainty of 1 PCT.
The spin depolarization and spin rotation parameters in 500 MeV P P elastic interactions. Additional normalization uncertainty of 1 PCT (2 PCT for DLL and DLS).
The elastic P P analysing power at 500 MeV incident proton energy. There is an additional overall normalization uncertainty of 1 PCT.
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No description provided.
The asymmetry ANN for pp elastic scattering has been measured at 800 and 650 MeV in the region of Coulomb-nuclear interference. The data have been analyzed to extract the real part of a spin-spin scattering amplitude. Results are compared with the predictions of forward dispersion relations. They disagree significantly at 650 MeV.
No description provided.
No description provided.
An experimental investigation of the structure of identified quark and gluon jets is presented. Observables related to both the global and internal structure of jets are measured; this allows for test
The measured jet broadening distributions (B) in quark and gluon jets seperately.
Measured distributions of -LN(Y2), where Y2 is the differential one-subjet rate, that is the value of the subjet scale parameter where 2 jets appear from the single jet.
The mean subjet multiplicity (-1) for gluon jets and quark jets for different values of the subject resolution parameter Y0.
The absolute cross sections for the production of 11 C by 1.59 GeV and 4.19 GeV α-particles incident on natural carbon have been measured to be 46.4 ± 1.3 mb and 42.5 ± 1.1 mb respectively. These results, together with data reported at other energies, indicate that the C(α, X) 11 C cross section becomes approximately constant at a value of about 43 mb for energies above 3 GeV (750 MeV/n). A similar energy dependence is exhibited by the C(p, X) 11 C reaction whose cross section has been measured previously over an extensive energy range. The C(α, X) 11 C cross sections are found to be in good agreement with predictions of a semi-empirical model developed to describe nuclear fragmentation.
ALL SYSTEMATICAL ERRORS WERE INCLUDED INTO TABULATED ERRORS.
We report on a measurement of the ratio of the differential cross sections for W and Z boson production as a function of transverse momentum in proton-antiproton collisions at sqrt(s) = 1.8 TeV. This measurement uses data recorded by the D0 detector at the Fermilab Tevatron in 1994-1995. It represents the first investigation of a proposal that ratios between W and Z observables can be calculated reliably using perturbative QCD, even when the individual observables are not. Using the ratio of differential cross sections reduces both experimental and theoretical uncertainties, and can therefore provide smaller overall uncertainties in the measured mass and width of the W boson than current methods used at hadron colliders.
The measured W and Z0 cross sections used to compute the ratio.
The measured ratios of W+-/Z0 cross sections, corrected for the branching ratios BR(W-->e-nue)=0.1073+-0.0025 and BR(Z0-->E+E-)=0.033632+-0.000059 (PDG 2000). The error given is the total error, but note that the 4.3pct error in the luminosity cancels completely in the ratio.
We present a measurement of angular observables, $P_4'$, $P_5'$, $P_6'$, $P_8'$, in the decay $B^0 \to K^\ast(892)^0 \ell^+ \ell^-$, where $\ell^+\ell^-$ is either $e^+e^-$ or $\mu^+\mu^-$. The analysis is performed on a data sample corresponding to an integrated luminosity of $711~\mathrm{fb}^{-1}$ containing $772\times 10^{6}$ $B\bar B$ pairs, collected at the $\Upsilon(4S)$ resonance with the Belle detector at the asymmetric-energy $e^+e^-$ collider KEKB. Four angular observables, $P_{4,5,6,8}'$ are extracted in five bins of the invariant mass squared of the lepton system, $q^2$. We compare our results for $P_{4,5,6,8}'$ with Standard Model predictions including the $q^2$ region in which the LHCb collaboration reported the so-called $P_5'$ anomaly.
Results of the angular analysis of $B^0 \to K^\ast(892)^0 \ell^+ \ell^-$ (where $\ell = e,\mu$) in five bins of $q^2$, the di-lepton invariant mass squared.
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