22,250 research outputs found
How to measure the Charm Density in the Proton at EIC
We study two experimental ways to measure the heavy-quark content of the
proton: using the Callan-Gross ratio and/or the azimuthal
asymmetry in deep inelastic lepton-nucleon scattering. Our
approach is based on the following observations. First, unlike the production
cross sections, the ratio and the azimuthal
asymmetry in heavy-quark leptoproduction are sufficiently stable, both
parametricallly and perturbatively, in a wide region of variables and
within the fixed-flavor-number scheme of QCD. Second, both these quantities,
and asymmetry, are sensitive to resummation of
the mass logarithms of the type within
the variable-flavor-number schemes. These two facts together imply that the
heavy-quark densities in the nucleon can, in principle, be determined from
high- data on the Callan-Gross ratio and/or the azimuthal asymmetry in
heavy-quark leptoproduction. In particular, the charm content of the proton can
be measured in future studies at the proposed Large Hadron-Electron (LHeC) and
Electron-Ion (EIC) Colliders.Comment: 9 pages, 4 figures, LaTeX. Talk given at the Workshop on Exclusive
Reactions at High Momentum Transfer (IV), May 18-21, 2010, TJNAF, Newport
News, VA and Electron-Ion Collider Collaboration Meeting, July 29-31, 2010,
Catholic University of America, Washington, D
On the polarization properties of the charmed baryon Lambda^+_c in the Lambda^+_c -> p + K^- + pi^+ + pi^0 decay
The polarization properties of the charmed Lambda^+_c baryon are investigated
in weak non-leptonic four-body Lambda^+_c -> p + K^- + pi^+ + pi^0 decay. The
probability of this decay and the angular distribution of the probability are
calculated in the effective quark model with chiral U(3)XU(3) symmetry
incorporating Heavy Quark Effective theory (HQET) and the extended
Nambu-Jona-Lasinio model with a linear realization of chiral U(3)XU(3)
symmetry. The theoretical value of the probability of the decay Lambda^+_c -> p
+ K^- + pi^+ + pi^0 relative to the probability of the decay Lambda^+_c -> p +
K^- + pi^+ does not contain free parameters and fits well experimental data.
The application of the obtained results to the analysis of the polarization of
the Lambda^+_c produced in the processes of photo and hadroproduction is
discussed.Comment: 10 pages, no figures, Late
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