2,077 research outputs found
Direct Detection of Light Dark Matter and Solar Neutrinos via Color Center Production in Crystals
We propose a new low-threshold direct-detection concept for dark matter and
for coherent nuclear scattering of solar neutrinos, based on the dissociation
of atoms and subsequent creation of color center type defects within a lattice.
The novelty in our approach lies in its ability to detect single defects in a
macroscopic bulk of material. This class of experiments features ultra-low
energy thresholds which allows for the probing of dark matter as light as
MeV through nuclear scattering. Another feature of defect
creation in crystals is directional information, which presents as a
spectacular signal and a handle on background reduction in the form of daily
modulation of the interaction rate. We discuss the envisioned setup and
detection technique, as well as background reduction. We further calculate the
expected rates for dark matter and solar neutrinos in two example crystals for
which available data exists, demonstrating the prospective sensitivity of such
experiments
Models of Dynamical R-Parity Violation
The presence of R-parity violating interactions may relieve the tension
between existing LHC constraints and natural supersymmetry. In this paper we
lay down the theoretical framework and explore models of dynamical R-parity
violation in which the breaking of R-parity is communicated to the visible
sector by heavy messenger fields. We find that R-parity violation is often
dominated by non-holomorphic operators that have so far been largely ignored,
and might require a modification of the existing searches at the LHC. The
dynamical origin implies that the effects of such operators are suppressed by
the ratio of either the light fermion masses or the supersymmetry breaking
scale to the mediation scale, thereby providing a natural explanation for the
smallness of R-parity violation. We consider various scenarios, classified by
whether R-parity violation, flavor breaking and/or supersymmetry breaking are
mediated by the same messenger fields. The most compact case, corresponding to
a deformation of the so called flavor mediation scenario, allows for the
mediation of supersymmetry breaking, R-parity breaking, and flavor symmetry
breaking in a unified manner.Comment: v2: references adde
Error Rates in Sex Determination of Human Skeletal Remains
The possible fallibility of forensic methods has been under scrutiny for over a decade. Left out of the initial reviews were methods within forensic anthropology. A literature review was conducted to examine modern methods in determining the biological sex of human skeleton remains and their associated error rates in making a correct determination. Results showed no significant correlation between the number of traits being considered the subsequent error rate in determining sex. The skull was shown to be the least accurate in determining biological sex with the pelvis showing the lowest rate of error. Finally, between regression line-based methods and observer-based methods, observer-based methods had a lower rate of error
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