Seminars and Colloquia

Title Speaker Location Material
Prospects for laboratory searches for Planck-scale Dark Matter William Terrano, PhD (Technische Universität München, München, Germany) Presentation at 3:45 PM, NPL 178 Coffee and cookies starting at 3:30 PM

will discuss the tantalizing prospect that Dark Matter is a
relic of physics at the Planck-scale, where quantum gravity
effects are expected to become important. I will review
how physics at such high energy scales can produce
low-energy relics and describe the properties of Dark
Matter if it is in fact such a relic. I’ll then look at whether
there is any hope for a laboratory detection of Planck-scale
Dark Matter through its spin-couplings, taking advantage of
the recent great strides — thanks to medical physics
applications — in producing large quantities of
coherently-polarized nucleons.

Status of the Mu3e experiment Dr. Frederik Wauters (Johannes Gutenberg-Universität, Mainz, Germany) Presentation at 3:45 PM, NPL 178 Coffee and cookies starting at 3:30 PM

The upcoming Mu3e experiment searches for the lepton
flavour violating decay μ + →e + e e + aiming for a final single
event sensitivity of 1 x 10 -16 . We are currently finalizing the
design of the first phase, which will have single event
sensitivity of 2 x 10 -15 , which will exploit the current muon
rates available at the Paul Scherrer Institute. The Mu3e
detector consist of 4 layers of ultra-thin silicon pixels
developed for this experiment, combined with scintillating
fibers and tile timing detectors to deal with the high decay
rates. Current prototypes meet all requirements, and the
project is moving from the R&D phase to construction.

Short-Range Correlations in nuclei Erez O. Cohen (School of Physics and Astronomy, Tel Aviv University, Israel) Presentation at 3:45 PM, NPL 178 Coffee and cookies starting at 3:30 PM

Short-range correlated (SRC) nucleon pairs are a vital part
of the nucleus, accounting for almost all nucleons with
momentum greater than the Fermi momentum (k​F​ ). A
fundamental characteristic of SRC pairs is having large
relative momenta, and smaller center-of-mass momenta as
compared to k​F​ . Knowledge of the c.m. momentum is
essential for understanding the formation mechanism of
SRC pairs. I will report on the extraction of SRC c.m.
motion from measurements of the A(e,e’pp) reaction at
Jefferson Lab.

The Standard Model and Beyond through β-decay Leendert Hayen (Katholieke Universiteit Leuven, Belgium) Presentation at 3:45 PM, NPL 178 Coffee and cookies starting at 3:30 PM

The study of nuclear beta decay has guided our physical
understanding of the universe throughout most of the 20​ th century,
directly leading to the unification of electromagnetic and weak
forces and the Standard Model. With new physics seemingly out of
reach with modern colliders, low energy searches for Beyond
Standard Model physics become even more valuable,
consolidating the role of nuclear beta decay as physics moves
forward. With experiments breaking new ground, we will review the
theoretical progress on the beta spectrum shape and frame its role
in ongoing and future tests of exotic currents in the weak
interaction. We will analyze its position in the so-called reactor
antineutrino anomaly which points towards the existence of a
fourth, sterile neutrino. In doing so, we illustrate the influence of
nuclear structure in the outstanding problems and conclusions.

qBOUNCE, a Quantum Bouncing Ball Gravity Spectrometer Prof. Dr. Hartmut Abele (Atominstitut – TU Wien, Austria) Presentation at 3:45 PM, NPL 178 Coffee and cookies starting at 3:30 PM

This talk focuses on the control and understanding of a
gravitationally interacting elementary quantum system
using the techniques of resonance spectroscopy. It offers a
new way of looking at gravitation at short distances based
on quantum interference. The ultra-cold neutron reflects
from a mirror in well-defined quantum states in the gravity
potential of the earth allowing the application of gravity
resonance spectroscopy (GRS). GRS relies on frequency
measurements, which provide a spectacular sensitivity.

Trapped Atoms and Ions for Tests of the Charged Electroweak Interaction Prof. Dan Melconian, PhD (Cyclotron Institute/Dept of Physics & Astronomy, Texas A&M University) Presentation at 3:45 PM, NPL 178 Coffee and cookies starting at 3:30 PM

Nuclear decay has a long-standing history of shaping and testing the standard model of particle
physics, and it continues to this day with elegant, ultra-precise low-energy nuclear measurements.
Experiments observing the angular correlations between the electron, neutrino and recoil
momenta following the decay of (un)polarized nuclei can be used to search for exotic currents
contributing to the dominant V−A structure of the weak interaction. Precision measurements of
the correlation parameters to < 0.1% would be sensitive to (or meaningfully constrain) new
physics, complementing other searches at large-scale facilities like the LHC. Ion and atom traps
provide an ideal source of very cold, short-lived radioactive nuclei in an extremely clean and open
environment. As such, they are invaluable tools for precision measurements of β-decay
parameters. This talk will focus on two such efforts. The TAMUTRAP facility at the Cyclotron
Institute, Texas A&M University, will utilize an upgrade to the recently commissioned cylindrical
Penning trap – already the world’s largest with an inner diameter of 90 mm – to search for scalar
currents via the β-ν-correlation in the β-delayed proton decay of T = 2 nuclei. The other effort,
based at TRIUMF in Vancouver, Canada, utilizes neutral atom-trapping techniques with optical
pumping methods to highly polarize (> 99%) 37
K atoms. Recently, we determined the asymmetry
parameter, A​ β​ , to 0.3% precision, which is comparable to or better than any other nuclear
measurement, including the neutron.

On the new MiniBooNE/LSND results Gerry Garvey, PhD (University of Washington) Presentation at 3:00 PM, NPL 178 Coffee and cookies starting at 2:45 PM

I will present and provide some background for a recent
MiniBooNE/LSND posting on the arXiv (1805.12028). The
MiniBooNE result includes new recently analyzed data. The
excess of electron neutrino like events observed in both
MiniBooNE and LSND appears consistent. If interpreted as
muon-neutrino (muon-anti-neutrino) oscillating into electron-
neutrino (electron-anti-neutrino) via a light sterile neutrino, the
best fit has a probability of ~20% while a background only fit
has a ?2 probability of 5x10-7 relative to the best fit. I will also
present a recent update of an arXiv posting by the MINOS
collaboration (1710-06488v2) that would make an
interpretation employing a sterile neutrino highly unlikely.

Cosmic Rays from 10^15 to 10^20 eV Gordon Thomson, PhD (University of Utah) Presentation at 3:45 PM, NPL 178 Coffee and cookies starting at 3:30 PM

The energy range covered by the Telescope Array
experiment, from 2x1015 eV to 2x1020 eV, contains the
end of the galactic cosmic ray spectrum, the
galactic-extragalactic transition, important information
about the nature of cosmic rays throughout this energy
region, and what probably are the highest energy
particles in the universe. As time permits, I will discuss
measurements of the spectrum and composition of
cosmic rays, and searches for anisotropy (and hence the
sources of these particles).

Searches for supersymmetry in final states with photons in CMS Menglei Sun (Carnegie Mellon University) Presentation at 3:45 PM, NPL 178 Coffee and cookies starting at 3:30 PM

The Standard Model (SM) is very successful at explaining a wide
range of phenomena. With the discovery of the Higgs boson,
the SM is complete. Yet there are still many questions left
unanswered: Why is the Higgs mass so light when it receives
radiative corrections up to the Planck scale? What is dark
matter? The supersymmetric extension to the SM would
provide solutions to these problems. Models of supersymmetry
with general gauge-mediated supersymmetry breaking often
lead to final states containing photons and large missing
transverse momentum. In this talk, I will discuss the searches
for supersymmetry in events with photons in proton-proton
collisions at √S = 13 TeV at the CMS experiment.

First Search for Neutrinoless Double Beta Decay in 76Ge with the Majorana Demonstrator Walter Pettus, PhD (University of Washington) Presentation at 3:45 PM, NPL 178 Coffee and cookies starting at 3:30 PM

Neutrinoless double-beta decay (0νββ) is a hypothetical
lepton-number violating process that would establish the Majorana
nature of neutrinos and serve as an indirect probe of the absolute
neutrino mass. The Majorana Demonstrator is an array of high purity
Ge detectors at the 4850’ level of the Sanford Underground Research
Facility in South Dakota searching for 0νββ in 76 Ge. The experiment
consists of two modules totaling 44 kg of p-type point contact
detectors; the first module began data taking in June 2015, with the
entire array operational since August 2016. I will report the analysis
of the first 9.95 kg*yr of exposure from the MAJORANA
DEMONSTRATOR, achieving a half-life limit of >1.9×10 25 yr for 0νββ
decay of 76 Ge. The experiment has also demonstrated the best
energy resolution and a background consistent with the best
achieved of any 0νββ experiment. These results strongly position
76 Ge for a future tonne-scale 0νββ experiment.