1,084 research outputs found
Phonon-phonon interactions due to non-linear effects in a linear ion trap
We examine in detail the theory of the intrinsic non-linearities in the
dynamics of trapped ions due to the Coulomb interaction. In particular the
possibility of mode-mode coupling, which can be a source of decoherence in
trapped ion quantum computation, or, alternatively, can be exploited for
parametric down-conversion of phonons, is discussed and conditions under which
such coupling is possible are derived.Comment: 25 pages, 4 figure
Possible background reductions in double beta decay experiments
The background induced by radioactive impurities of and
in the source of the double beta experiment NEMO-3 has been
investigated. New methods of data analysis which decrease the background from
the above mentioned contamination are identified. The techniques can also be
applied to other double beta decay experiments capable of measuring
independently the energies of the two electrons.Comment: 15 pages, 13 figures, accepted in the Nuclear Instruments and Methods
Systematics of geometric scaling
Using all available data on the deep-inelastic cross-sections at HERA at
x<0.01, we look for geometric scaling of the form \sigma^{\gamma^*p}(\tau)
where the scaling variable \tau behaves alternatively like \log(Q^2)-\lambda Y,
as in the original definition, or \log(Q^2)-\lambda \sqrt{Y}, which is
suggested by the asymptotic properties of the Balitsky-Kovchegov (BK) equation
with running QCD coupling constant. A ``Quality Factor'' (QF) is defined,
quantifying the phenomenological validity of the scaling and the uncertainty on
the intercept \lambda. Both choices have a good QF, showing that the second
choice is as valid as the first one, predicted for fixed coupling constant. A
comparison between the QCD asymptotic predictions and data is made and the QF
analysis shows that the agreement can be reached, provided going beyond leading
logarithmic accuracy for the BK equation.Comment: 4 pages, 4 figure
Gluon saturation effects on the color singlet J/Psi production in high energy dA and AA collisions
We derive the formulae for the cross section of J/Psi production in high
energy pA and AA collisions taking into account the gluon saturation/color
glass condensate effects. We then perform the numerical calculations of the
corresponding nuclear modification factors and find a good agreement between
our calculations and the experimental data on J/Psi production in dA
collisions. We also observe that cold nuclear modification effects alone cannot
describe the data on J/Psi production in AA collisions. Additional final state
suppression (at RHIC) and enhancement (at LHC) mechanisms are required to
explain the experimental observations.Comment: 11 pages, 6 figure
Heavy-quark energy loss in pQCD and SYM plasmas
We consider heavy-quark energy loss and pT-broadening in a strongly-coupled
N=4 Super Yang Mills (SYM) plasma, and the problem of finite-extend matter is
addressed. When expressed in terms of the appropriate saturation momentum, one
finds identical parametric forms for the energy loss in pQCD and SYM theory,
while pT-broadening is radiation dominated in SYM theory and multiple
scattering dominated in pQCD.Comment: 5 pages, 2 figures, Proceedings of the IIIrd Workshop for Young
Scientists on the Physics of Ultrarelativistic Nucleus-Nucleus Collisions
(HotQuarks08), Estes Park, USA, August 18-23 200
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