The interaction of spins in a spin-polarized test mass and those in a paramagentic salt, separated by a μ-metal shield and a double-layer superconducting shield, was investigated. Our results set a limit on electron spin interactions and on moments which are not of electromagnetic origin. In terms of a standard dipole-dipole form, the limit is (2.7±2.4)×10−14 of the interaction strength between the magnetic moments of the electrons. Compared to previous results, this is more than a twentyfold improvement.
CONST is the interaction strength between the magnetic moments of the electrons in terms of a standard dipole-dipole form.
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NC, CF, and TF are the color factors for SU(N) group. For SU(3) they are equal to: NC = 3, CF = 4/3, and TF = 1/2.
Absolute cross sections for Compton scattering from protons have been determined at 180° for the backscattered photon at incident laboratory photon energies of 98 and 132 MeV. For the difference between the electric and the magnetic polarizability of the proton a value of (7.03 − 2.37 +2.49 − 2.05 +2.14 ) × 10 −4 fm 3 has been derived using the predictions from calculations based on relativistic dispersion relations.
No description provided.
From 2540 Z 0 → τ + τ − events, we determine the inclusive decay branching fractions of the τ -lepton into one and three charged particles to be 0.856 ± 0.006 (stat.) ± 0.003 (syst.) and 0.144 ± 0.006 (stat.) ± 0.003 (syst.), respectively. The leptonic branching fractions are measured to be 0.175 ± 0.008 (stat.) ± 0.005 (syst.) for τ → μν μ ντ and 0.177 ± 0.007 (stat.) ± 0.006 (syst.) for τ → eν e ν τ . We determined the τ lifetime both from three-prong decays using the decay length and from one-prong decays using the impact parameter. The results from the two independent methods agree and yield a combined value of [0.309 ± 0.023 (stat.) ± 0.030 (syst.)] × 10 −12 s.
ALPHAS extracted from the ratio of the branching fractions.
Data on stable hadron production in p + p and p + n interactions at 200 GeV/ c are reviewed. Methods to construct missing data in the p + p, p + n, and n + n interactions are derived from charge symmetry and charge, baryon and strangeness conservation, and used to yield nucleon-nucleon interaction results. These may be useful for evaluating nucleus-nucleus collision measurements in terms of enhancements and suppressions. Parameterizations of p t 2 and rapidity distributions are presented to provide yields in acceptance cuts for comparisons to nucleus-nucleus data. As an example the derived nucleon-nucleon multiplicities are reduced to the acceptances of the NA-35 CERN S + S experiment.
No description provided.
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The ratio of the branching fractions for p p →K + K − and p p →π + π − was determined with the CPLEAR detector, by stopping antiprotons in a gaseous hydrogen target at 15 bar pressure. It was found to be BR(K + K − )/BR( π + π − )=0.205± 0.016. The fraction of P-wave annihilation at rest at this target density was deduced to be (38±9)%.
CONST is the fraction of P-wave annihilation in gaseous hydrogen at pressu re of 15 bar. In the SIG/SIG the statistical and systematic errors are added qu adratically.
In four-jet events from e + e − →Z 0 →multihadrons one can separate the three principal contributions from the triple-gluon vertex, double gluon-bremsstrahlung and the secondary quark-antiquark production, using the shape of the two-dimensional angular distributions in the generalized Nachtmann-Reiter angle θ NR ∗ and the opening angle of the secondary jets. Thus one can identify directly the contribution from the triple-gluon vertex without comparison with a specific non-QCD model. Applying this new method to events taken with the DELPHI-detector we get for the ratio of the colour factor N c to the fermionic Casimir operator C F : N c C F = 2.55 ± 0.55 ( stat. ) ± 0.4 ( fragm. + models ) ± 0.2 ( error in bias ) in agreement with the value 2.25 expected in QCD from N c =3 and C F = 4 3 .
NC, CF, and TR are the color factors for SU(3) group.
We present measurement of the π0γ*γ, ηγ*γ and η′γ*γ form factors. The π0-form factor is for the first time observed in the space-like region. The transition form factor of the η-meson is determined from its decay modes π+π−π0, π+π−γ and the neutral decay mode γγ. The decay of the η′ is observed in the decay channels ργ, ηπ+π− with η→γγ and in the four charged prong final state stemming from ηπ+π− with the η decaying into π+π−(π0/γ). All form factors agree well with a simple ρ-pole predicted by the vector meson dominance model and also with the QCD inspired Brodsky-Lepage model.
No description provided.
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HERE XL IS CUMULATIVE NUMBER, DEFINED AS FOLLOWS: (E-PL)/M(NUCLEON). THE DISTRIBUTION (1/N)*D(N)/D(XL) WAS FITTED BY THE SUM: CONST(1)* EXP(-SLOPE(1)*XL)+CONST(2)*EXP(-SLOPE(2)*XL).
HERE XL IS CUMULATIVE NUMBER, DEFINED AS FOLLOWS: (E-PL)/M(NUCLEON). THE DISTRIBUTION (XL/N)*D(N)/D(XL) WAS FITTED BY THE SUM: CONST(1)* EXP(-SLOPE(1)*XL)+CONST(2)*EXP(-SLOPE(2)*XL).
HERE XL IS CUMULATIVE NUMBER, DEFINED AS FOLLOWS: (E-PL)/M(NUCLEON).
A search for the 0 + → 2 + neutrinoless double-beta decay of 76 Ge into the first excited state of 76 Se has been carried out using a coincidence technique between Ge and NaI detectors. Since the expected number of counts is very small and mixed with a continuous background of natural radioactivity, special care has been taken to maintain the good energy resolution of the detectors. As a consequence, the experimental data display, after 6207 h statistical time, a coincidence signal of 19.3 ± 5.8 counts, between an energy deposition of 1484.0 ± 0.3 keV in the Ge detectors and 561 ± 10 keV in the NaI detectors. Both Ge and NaI energies are within the experimental errors, compatible with the expected values. No other unidentified coincidence signal has been found in the full Ge-NaI energy matrix, and no similar γγ cascade has been found within our background. Even if the low statistics does not completely rule out the possibility of a statistical fluctuation, this result should encourage further experiments with improved sensitivities.
SE76* IS IN 2+ EXGITED STATE.
Forum