13,553 research outputs found
DVCS on nuclei: Observability and Consequences
In this paper, we discuss the feasibility of measuring deeply virtual Compton
scattering (DVCS) on nuclei in a collider setting, as for example, the planned
high-luminosity Electron-Ion-Collider (EIC). We demonstrate that employing our
recent model for nuclear generalized parton distributions (nGPDs), the
one-photon unpolarized DVCS cross section as well as the azimuthal- and spin
asymmetry are of the same size as in the proton case. This will allow for an
experimental extraction of nuclear GPDs with high precision shedding new light
on nuclear shadowing at small and the interplay of shadowing and
nuclear enhancement at .Comment: 9 pages, 18 figures, uses EPJ style format, final version to appear
in EPJ
Single spin asymmetry in DVCS
In the following note, we will present an estimation of the single spin
asymmetry in deeply virtual Compton scattering (DVCS) which directly allows one
to test predictions of the ratio of the imaginary part of the amplitude in DIS
to DVCS, as well as access the skewed parton distributions at small in the
DGLAP region. We find it to be large for the HERA kinematics to be accessible
in forthcoming runs with polarized electrons.Comment: 6 pages, 2 figures in eps format. Submitted to Phys. Rev. D's Rapid
Communication
Masses and Mixings from Neutrino Beams pointing to Neutrino Telescopes
We discuss the potential to determine leading oscillation parameters, the
value and the sign of \Delta m^2_{31}, as well as the magnitude of \sin^2
2\theta_{13} using a conventional wide band neutrino beam pointing to water or
ice Cherenkov neutrino detectors known as ``Neutrino Telescopes''. We find that
precision measurements of \Delta m^2_{31} and \theta_{23} are possible and
that, even though it is not possible to discriminate between charges in the
detector, there is a remarkably good sensitivity to the mixing angle
\theta_{13} and the sign of \Delta m^2_{31}.Comment: 9 pages, 4 figure
Efficient frequency doubler for the soft X-ray SASE FEL at the TESLA Test Facility
This paper describes an effective frequency doubler scheme for SASE free
electron lasers. It consists of an undulator tuned to the first harmonic, a
dispersion section, and a tapered undulator tuned to the second harmonic. The
first stage is a conventional soft X-ray SASE FEL. Its gain is controlled in
such a way that the maximum energy modulation of the electron beam at the exit
is about equal to the local energy spread, but still far away from saturation.
When the electron bunch passes through the dispersion section this energy
modulation leads to effective compression of the particles. Then the bunched
electron beam enters the tapered undulator and produces strong radiation in the
process of coherent deceleration. We demonstrate that a frequency doubler
scheme can be integrated into the SASE FEL at the TESLA Test Facility at DESY,
and will allow to reach 3 nm wavelength with GW-level of output peak power.
This would extend the operating range of the FEL into the so-called water
window and significantly expand the capabilities of the TTF FEL user facility.Comment: 17 pages, 13 figure
Systematic Exploration of the Neutrino Factory Parameter Space including Errors and Correlations
We discuss in a systematic way the extraction of neutrino masses, mixing
angles and leptonic CP violation at neutrino factories. Compared to previous
studies we put a special emphasis on improved statistical methods and on the
multidimensional nature of the combined fits of the nu_e -> nu_mu, \bar nu_e ->
\bar nu_mu appearance and nu_mu -> nu_mu, \bar nu_mu -> \bar nu_mu
disappearance channels. Uncertainties of all involved parameters and
statistical errors are included. We find previously ignored correlations in the
multidimensional parameter space, leading to modifications in the physics
reach, which amount in some cases to one order of magnitude. Including proper
statistical errors we determine for all parameters the improved sensitivity
limits for various baselines, beam energies, neutrino fluxes and detector
masses. Our results allow a comparison of the physics potential for different
choices of baseline and beam energy with regard to all involved parameters. In
addition we discuss in more detail the problem of parameter degeneracies in
measurements of delta_CP.Comment: 29 pages, 14 fugure
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