45,259 research outputs found
The Two-Nucleon 1S0 Amplitude Zero in Chiral Effective Field Theory
We present a new rearrangement of short-range interactions in the
nucleon-nucleon channel within Chiral Effective Field Theory. This is intended
to reproduce the amplitude zero (scattering momentum 340 MeV) at
leading order, and it includes subleading corrections perturbatively in a way
that is consistent with renormalization-group invariance. Systematic
improvement is shown at next-to-leading order, and we obtain results that fit
empirical phase shifts remarkably well all the way up to the pion-production
threshold. An approach in which pions have been integrated out is included,
which allows us to derive analytic results that also fit phenomenology
surprisingly well.Comment: 34 pages, 7 figure
The symmetries of the Dirac--Pauli equation in two and three dimensions
We calculate all symmetries of the Dirac-Pauli equation in two-dimensional
and three-dimensional Euclidean space. Further, we use our results for an
investigation of the issue of zero mode degeneracy. We construct explicitly a
class of multiple zero modes with their gauge potentials.Comment: 22 pages, Latex. Final version as published in JMP. Contains an
additional subsection (4.2) with the explicit construction of multiple zero
mode
Light charged Higgs boson production at the Large Hadron electron Collider
We study the production of a light charged Higgs boson at the future Large
Hadron electron Collider (LHeC), through the process
considering both decay channels and in the final state. We analyse these processes in the context of the
2-Higgs Doublet Model Type III (2HDM-III) and assess the LHeC sensitivity to
such signals against a variety of both reducible and irreducible
backgrounds. We confirm that prospects for detection in the 2HDM-III are
excellent assuming standard collider energy and luminosity conditions.Comment: 12 pages, 12 figures. Accepted in Physical Review
Coherent spin rotations in open driven double quantum dots
We analyze the charge and spin dynamics in a DC biased double quantum dot
driven by crossed DC and AC magnetic fields. In this configuration, spatial
delocalization due to inter-dot tunnel competes with intra-dot spin rotations
induced by the time dependent magnetic field, giving rise to a complicated time
dependent behavior of the tunnelling current. When the Zeeman splitting has the
same value in both dots and spin flip is negligible, the electrons remain in
the triplet subspace (dark subspace) performing coherent spin rotations and the
current does not flow. This electronic trapping is removed either by finite
spin relaxation or when the Zeeman splitting is different in each quantum dot.
In the first case, our results show that measuring the current will allow to
get information on the spin relaxation time. In the last case, we will show
that applying a resonant bichromatic magnetic field, the electrons become
trapped in a coherent superposition of states and electronic transport is
blocked. Then, manipulating AC magnetic fields, electrons are driven to perform
coherent spin rotations which can be unambiguously detected by direct
measurement of the tunneling current.Comment: 7 pages, 6 figures. Extended published versio
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