80 research outputs found
Large enhancement of deuteron polarization with frequency modulated microwaves
We report a large enhancement of 1.7 in deuteron polarization up to values of
0.6 due to frequency modulation of the polarizing microwaves in a two liters
polarized target using the method of dynamic nuclear polarization. This target
was used during a deep inelastic polarized muon-deuteron scattering experiment
at CERN. Measurements of the electron paramagnetic resonance absorption spectra
show that frequency modulation gives rise to additional microwave absorption in
the spectral wings. Although these results are not understood theoretically,
they may provide a useful testing ground for the deeper understanding of
dynamic nuclear polarization.Comment: 10 pages, including the figures coming in uuencoded compressed tar
files in poltar.uu, which also brings cernart.sty and crna12.sty files neede
Spin Structure of the Proton from Polarized Inclusive Deep-Inelastic Muon-Proton Scattering
We have measured the spin-dependent structure function in inclusive
deep-inelastic scattering of polarized muons off polarized protons, in the
kinematic range and . A
next-to-leading order QCD analysis is used to evolve the measured
to a fixed . The first moment of at is .
This result is below the prediction of the Ellis-Jaffe sum rule by more than
two standard deviations. The singlet axial charge is found to be . In the Adler-Bardeen factorization scheme, is
required to bring in agreement with the Quark-Parton Model. A
combined analysis of all available proton and deuteron data confirms the
Bjorken sum rule.Comment: 33 pages, 22 figures, uses ReVTex and smc.sty. submitted to Physical
Review
Leading-order QCD Analysis of Neutrino-Induced Dimuon Events
The results of a leading-order QCD analysis of neutrino-induced charm production are presented. They are based on a sample of 4111 \numu- and 871 \anumu-induced opposite-sign dimuon events with , , observed in the CHARM~II detector exposed to the CERN wideband neutrino and antineutrino beams. The analysis yields the value of \linebreak the charm quark mass and the Cabibbo--Kobayashi--Maskawa matrix element . The strange quark content of the nucleon is found to be suppressed with respect to non-strange sea quarks by a factor
Experimental search for muonic photons
We report new limits on the production of muonic photons in the CERN neutrino beam. The results are based on the analysis of neutrino production of dimuons in the CHARM II detector. A CL limit on the coupling constant of muonic photons, is derived for a muon neutrino mass in the range eV. This improves the limit obtained from a precision measurement of the anomalous magnetic moment of the muon by a factor from 8 to 4
Measurement of the spin-dependent structure function g1(x) of the proton
Adams D, Adeva B, Arik E, et al. Measurement of the spin-dependent structure function g1(x) of the proton. Phys.Lett. B. 1994;329(2-3):399-406.We have measured the spin-dependent structure function of the proton in deep inelastic scattering of polarized muons off polarized protons, in the kinematic range and 1\,\mbox{GeV}~2
. Its first moment, , is found to be 0.136 \pm 0.011\,(\mbox{stat.})\pm 0.011\,(\mbox{syst.}) at Q~2=10\,\mbox{GeV}~2. This value is smaller than the prediction of the Ellis--Jaffe sum rule by two standard deviations, and is consistent with previous measurements. A combined analysis of all available proton, deuteron and neutron data confirms the Bjorken sum rule to within of the theoretical value
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