5,241 research outputs found
Shock-wave therapy of gastric outlet syndrome caused by a gallstone
A patient with gastric outlet syndrome (Bouveret's syndrome) caused by a large gallstone impacted in the duodenal bulb was successfully treated by extracorporeal shock-wave lithotripsy. Thus, open abdominal surgery could be avoided. For disintegration of the stone, three consecutive lithotripsy procedures were necessary. Thereafter, stone fragments could be extracted endoscopically. Extracorporeal shock-wave lithotripsy could become a non-surgical alternative in patients with obstruction of the duodenum caused by a gallstone
Better Higgs-CP Tests Through Information Geometry
Measuring the CP symmetry in the Higgs sector is one of the key tasks of the
LHC and a crucial ingredient for precision studies, for example in the language
of effective Lagrangians. We systematically analyze which LHC signatures offer
dedicated CP measurements in the Higgs-gauge sector, and discuss the nature of
the information they provide. Based on the Fisher information measure, we
compare the maximal reach for CP-violating effects in weak boson fusion,
associated ZH production, and Higgs decays into four leptons. We find a subtle
balance between more theory-independent approaches and more powerful analysis
channels, indicating that rigorous evidence for CP violation in the Higgs-gauge
sector will likely require a multi-step process.Comment: 27 pages, 8 figure
Early Thermal Evolution of Planetesimals and its Impact on Processing and Dating of Meteoritic Material
Radioisotopic ages for meteorites and their components provide constraints on
the evolution of small bodies: timescales of accretion, thermal and aqueous
metamorphism, differentiation, cooling and impact metamorphism. Realising that
the decay heat of short-lived nuclides (e.g. 26Al, 60Fe), was the main heat
source driving differentiation and metamorphism, thermal modeling of small
bodies is of utmost importance to set individual meteorite age data into the
general context of the thermal evolution of their parent bodies, and to derive
general conclusions about the nature of planetary building blocks in the early
solar system. As a general result, modelling easily explains that iron
meteorites are older than chondrites, as early formed planetesimals experienced
a higher concentration of short-lived nuclides and more severe heating.
However, core formation processes may also extend to 10 Ma after formation of
Calcium-Aluminum-rich inclusions (CAIs). A general effect of the porous nature
of the starting material is that relatively small bodies (< few km) will also
differentiate if they form within 2 Ma after CAIs. A particular interesting
feature to be explored is the possibility that some chondrites may derive from
the outer undifferentiated layers of asteroids that are differentiated in their
interiors. This could explain the presence of remnant magnetization in some
chondrites due to a planetary magnetic field.Comment: 24 pages, 9 figures, Accepted for publication as a chapter in
Protostars and Planets VI, University of Arizona Press (2014), eds. H.
Beuther, R. Klessen, C. Dullemond, Th. Hennin
Resonance Searches with an Updated Top Tagger
The performance of top taggers, for example in resonance searches, can be
significantly enhanced through an increased set of variables, with a special
focus on final-state radiation. We study the production and the decay of a
heavy gauge boson in the upcoming LHC run. For constant signal efficiency, the
multivariate analysis achieves an increased background rejection by up to a
factor 30 compared to our previous tagger. Based on this study and the
documentation in the Appendix we release a new HEPTopTagger2 for the upcoming
LHC run. It now includes an optimal choice of the size of the fat jet,
N-subjettiness, and different modes of Qjets.Comment: 26 page
A tunnel and a traffic jam: How transition disks maintain a detectable warm dust component despite the presence of a large planet-carved gap
We combined hydrodynamical simulations of planet-disk interactions with dust
evolution models that include coagulation and fragmentation of dust grains over
a large range of radii and derived observational properties using radiative
transfer calculations. We studied the role of the snow line in the survival of
the inner disk of transition disks. Inside the snow line, the lack of ice
mantles in dust particles decreases the sticking efficiency between grains. As
a consequence, particles fragment at lower collision velocities than in regions
beyond the snow line. This effect allows small particles to be maintained for
up to a few Myrs within the first astronomical unit. These particles are
closely coupled to the gas and do not drift significantly with respect to the
gas. For lower mass planets (1), the pre-transition appearance
can be maintained even longer because dust still trickles through the gap
created by the planet, moves invisibly and quickly in the form of relatively
large grains through the gap, and becomes visible again as it fragments and
gets slowed down inside of the snow line. The global study of dust evolution of
a disk with an embedded planet, including the changes of the dust aerodynamics
near the snow line, can explain the concentration of millimetre-sized particles
in the outer disk and the survival of the dust in the inner disk if a large
dust trap is present in the outer disk. This behaviour solves the conundrum of
the combination of both near-infrared excess and ring-like millimetre emission
observed in several transition disks.Comment: Accepted for publication in A&A (including acknowledgments
The Higgs Legacy of the LHC Run I
Based on Run I data we present a comprehensive analysis of Higgs couplings.
For the first time this SFitter analysis includes independent tests of the
Higgs-gluon and top Yukawa couplings, Higgs decays to invisible particles, and
off-shell Higgs measurements. The observed Higgs boson is fully consistent with
the Standard Model, both in terms of coupling modifications and effective field
theory. Based only on Higgs total rates the results using both approaches are
essentially equivalent, with the exception of strong correlations in the
parameter space induced by effective operators. These correlations can be
controlled through additional experimental input, namely kinematic
distributions. Including kinematic distributions the typical Run I reach for
weakly interacting new physics now reaches 300 to 500 GeV.Comment: 29 pages, 15 figure
Excitation spectra and rf-response near the polaron-to-molecule transition from the functional renormalization group
A light impurity in a Fermi sea undergoes a transition from a polaron to a
molecule for increasing interaction. We develop a new method to compute the
spectral functions of the polaron and molecule in a unified framework based on
the functional renormalization group with full self-energy feedback. We discuss
the energy spectra and decay widths of the attractive and repulsive polaron
branches as well as the molecular bound state and confirm the scaling of the
excited state decay rate near the transition. The quasi-particle weight of the
polaron shifts from the attractive to the repulsive branch across the
transition, while the molecular bound state has a very small residue
characteristic for a composite particle. We propose an experimental procedure
to measure the repulsive branch in a Li6 Fermi gas using rf-spectroscopy and
calculate the corresponding spectra.Comment: 15 pages, 13 figures; v2: version published in Phys. Rev.
Quantum critical behavior in strongly interacting Rydberg gases
We study the appearance of correlated many-body phenomena in an ensemble of
atoms driven resonantly into a strongly interacting Rydberg state. The ground
state of the Hamiltonian describing the driven system exhibits a second order
quantum phase transition. We derive the critical theory for the quantum phase
transition and show that it describes the properties of the driven Rydberg
system in the saturated regime. We find that the suppression of Rydberg
excitations known as blockade phenomena exhibits an algebraic scaling law with
a universal exponent.Comment: 4 pages, 3 figures, published versio
- …