4,167 research outputs found
Ground state correlations in Deep Inelastic Scattering and the Drell-Yan process
Non-perturbative corrections to the LO cross section formulae for DIS and the
Drell-Yan process were calculated. The interaction of partons was taken into
account via dressing the incoming quark lines with spectral functions. We found
the effect of ground state correlation in DIS to be large in the region of
small Bjorken x and low momentum transfer Q. For a quark width of the order of
200 MeV, the deviation from parton model cross section reaches as much as 50%
for Q^2=10 GeV^2. On the other hand, for the values of Q well above the
resonance region, the effect of ISI turned out to be small in DIS, but still
substantial for the triple differential Drell-Yan cross section. Our
calculations show that the shape of the high mass Drell-Yan pair transverse
momentum distribution is fully determined by quark off-shellness. From
comparison to the resent data on the Drell-Yan cross section from NuSea
collaboration, we obtained for the quark width in the nucleon the value about
200 MeV.Comment: Talk presented on "IV international conference on Perspectives in
Hadronic Physics", to be published in the proceedings, 6 pages, 5 figures,
uses EPJ styl
Wannier-Stark resonances in optical and semiconductor superlattices
In this work, we discuss the resonance states of a quantum particle in a
periodic potential plus a static force. Originally this problem was formulated
for a crystal electron subject to a static electric field and it is nowadays
known as the Wannier-Stark problem. We describe a novel approach to the
Wannier-Stark problem developed in recent years. This approach allows to
compute the complex energy spectrum of a Wannier-Stark system as the poles of a
rigorously constructed scattering matrix and solves the Wannier-Stark problem
without any approximation. The suggested method is very efficient from the
numerical point of view and has proven to be a powerful analytic tool for
Wannier-Stark resonances appearing in different physical systems such as
optical lattices or semiconductor superlattices.Comment: 94 pages, 41 figures, typos corrected, references adde
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