71 research outputs found
Stealth Supersymmetry
We present a broad class of supersymmetric models that preserve R-parity but
lack missing energy signatures. These models have new light particles with
weak-scale supersymmetric masses that feel SUSY breaking only through couplings
to the MSSM. This small SUSY breaking leads to nearly degenerate fermion/boson
pairs, with small mass splittings and hence small phase space for decays
carrying away invisible energy. The simplest scenario has low-scale SUSY
breaking, with missing energy only from soft gravitinos. This scenario is
natural, lacks artificial tunings to produce a squeezed spectrum, and is
consistent with gauge coupling unification. The resulting collider signals will
be jet-rich events containing false resonances that could resemble signatures
of R-parity violation. We discuss several concrete examples of the general
idea, and emphasize gamma + jet + jet resonances, displaced vertices, and very
large numbers of b-jets as three possible discovery modes.Comment: 12 pages, 4 figure
Light Sterile Neutrinos and Short Baseline Neutrino Oscillation Anomalies
We study two possible explanations for short baseline neutrino oscillation
anomalies, such as the LSND and MiniBooNE anti-neutrino data, and for the
reactor anomaly. The first scenario is the mini-seesaw mechanism with two
eV-scale sterile neutrinos. We present both analytic formulas and numerical
results showing that this scenario could account for the short baseline and
reactor anomalies and is consistent with the observed masses and mixings of the
three active neutrinos. We also show that this scenario could arise naturally
from an effective theory containing a TeV-scale VEV, which could be related to
other TeV-scale physics. The minimal version of the mini-seesaw relates the
active-sterile mixings to five real parameters and favors an inverted
hierarchy. It has the interesting property that the effective Majorana mass for
neutrinoless double beta decay vanishes, while the effective masses relevant to
tritium beta decay and to cosmology are respectively around 0.2 and 2.4 eV. The
second scenario contains only one eV-scale sterile neutrino but with an
effective non-unitary mixing matrix between the light sterile and active
neutrinos. We find that though this may explain the anomalies, if the
non-unitarity originates from a heavy sterile neutrino with a large
(fine-tuned) mixing angle, this scenario is highly constrained by cosmological
and laboratory observations.Comment: 25 pages, 6 figure
CoNIC Challenge: Pushing the Frontiers of Nuclear Detection, Segmentation, Classification and Counting
Nuclear detection, segmentation and morphometric profiling are essential in
helping us further understand the relationship between histology and patient
outcome. To drive innovation in this area, we setup a community-wide challenge
using the largest available dataset of its kind to assess nuclear segmentation
and cellular composition. Our challenge, named CoNIC, stimulated the
development of reproducible algorithms for cellular recognition with real-time
result inspection on public leaderboards. We conducted an extensive
post-challenge analysis based on the top-performing models using 1,658
whole-slide images of colon tissue. With around 700 million detected nuclei per
model, associated features were used for dysplasia grading and survival
analysis, where we demonstrated that the challenge's improvement over the
previous state-of-the-art led to significant boosts in downstream performance.
Our findings also suggest that eosinophils and neutrophils play an important
role in the tumour microevironment. We release challenge models and WSI-level
results to foster the development of further methods for biomarker discovery
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