Seminars and Colloquia

Title Speaker Location Material
Search for Vector Boson Scattering with W/Z boson jet at ATLAS Tatsumi Natta, PhD Waseda University (Japan) Cookies and Coffee starting at 3:30pm; Presentation at 3:45pm
Vector boson scattering (VBS) is a key process to probe the electroweak symmetry breaking (EWSB) of the Standard Model, since it involves both self-couplings of the vector bosons and the coupling with Higgs boson. If the Higgs mechanism is not the sole source of EWSB, the scattering amplitude deviates from SM prediction at high scattering energy.  Moreover, deviation may be detectable even if a new physics scale is higher than reach of direct search. The LHC-ATLAS experiment have been finished 3 years Run2 physics program at √s = 13 TeV. In this talk, I will present recent study of VBS at Run2 focussing on final states having boosted W/Z jets. The boosted W/Z jets tagging is one of key techniques to probe the most energetic scatting W/Z boson in the VBS process. The recent development of boson tagging techniques is also presented.
Nuclear reactor and astrophysics neutrinos with the JUNO experiement Mariangela Settimo, PhD SUBATECH CNRS (France) Presentation at 3:45pm Coffee and Cookies starting at 3:30pm
The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid scintillator underground detector, under construction in China. The main goal of the experiment is the neutrino mass hierarchy determination
and the high-precision neutrino oscillation parameter measurements, detecting electron anti-neutrinos emitted from two nearby (baseline of about 53 km) nuclear power plants. JUNO experiment is not only a reactor neutrino experiment for the mass hierarchy and oscillation, but also for supernova and astrophysics studies. In this seminar, I will briefly presents the physics perspectives and give a status of its construction.
Results from sub-GeV dark matter searches and high voltage breakdown studies in liquid argon and xenon Lucie Tvrznikova, Phd (Lawrence Livermore National Laboratory) Presentation at 3:45 PM, NPL 178 Coffee and cookies starting at 3:30 PM

Sub-GeV WIMP dark matter (DM) is usually difficult to probe using liquid xenon
detectors due to a small energy transfer in DM-nucleus interactions and a finite
detector threshold. However, two novel direct detection methods overcome this
limitation: the Bremsstrahlung and Migdal effects allow us to consider electron recoils
that accompany the standard DM-nucleus scattering, thereby extending the reach to
lower DM masses. I will present constraints on DM-nucleon scattering using data
acquired in 2013 by the Large Underground Xenon (LUX) experiment. Looking ahead,
the increasingly large noble liquid detectors are facing challenges with applications of
high voltage (HV). The Xenon Breakdown Apparatus (XeBrA) at the Lawrence Berkeley
National Laboratory was built to characterize the HV behavior of liquid xenon and liquid
argon. Results from XeBrA serve not only to improve our understanding of the physical
processes involved in the breakdown but also to inform the future of noble liquid
detector engineering and neutrinoless double beta decay searches.

Quantum computing for nuclear physics: status and expectations Natalie Klco (Institute for Nuclear Theory, UW, Seattle) Presentation at 2:45 PM, NPL 178 Coffee and cookies starting at 2:15 PM

Studying nature directly from quark and gluon degrees of freedom is often
computationally limited by nature's physical characteristics of exponentially growing
Hilbert spaces with particle number and sign/signal-to-noise problems. As a result,
Minkowski-space dynamics and fermionic many-body structure calculations require
exponentially large classical computing resources to provide results with necessary
precision. This leaves many systems of interest to nuclear and particle physics (finite
density systems, fragmentation functions, non-equilibrium systems etc.) intractable for
known algorithms with current and foreseeable classical computational resources.
Fortunately, there are good reasons to expect that it will be efficient to simulate
locally-interacting quantum systems with quantum systems. By leveraging their natural
capacity to represent wavefunctions and directly manipulate amplitudes rather than
probabilities, the use of quantum systems as a computational framework leads to
constructions of basic quantum field theories with resource requirements that scale
only polynomially with the precision and size of the system. In this talk, I will present an
overview of recent efforts in, and the potential for, quantum computing to address
important aspects of quantum field theories relevant to nuclear physic

Search for New Physics with Neutrinoless Double-β Decay The Ge-76 Experimental Program Dr. Matteo Agostini (Technische Universität München, Germany) Presentation at 3:45 PM, NPL 178 Coffee and cookies starting at ​ 3:30 PM

The neutrinoless double-β decay is a hypothetical nuclear
transition predicted by most of the theories that explain the origin
of neutrino masses or the dominance of matter over antimatter in
our Universe. Its discovery would unambiguously prove that the
lepton number is not conserved and neutrinos are their own
antiparticles. The experimental search for the neutrinoless
double-β decay is a very active and rapidly growing field, with
several experiments running and many others under preparation.
The talk will cover the theoretical and experimental aspects
connected to the neutrinoless double-β decay, with focus on the
experimental program based on Ge-76.

Atomic parity violation and searching for dark matter with magnetic resonance: recent results from Mainz Prof. Dr. Dimitry Budker (Johannes Gutenberg-Universität Mainz, Germany) Presentation at 10:30 AM, NPL 178 Coffee and cookies starting at 10:15 AM

We will discuss a measurement of atomic parity violation in a
chain of Yb isotopes and the progress in the CASPEr
experiments, including the recent results of the search for
ultralight dark-matter fields with zero- and ultralow-field (ZULF)
nuclear magnetic resonance.

The Compact Binary Census after LIGO/Virgo's Second Observing Run Prof. Ben Farr, PhD (University of Oregon, Eugene) Presentation at 3:45 PM, NPL 178 Coffee and cookies starting at 3:30 PM

With 5.9 binary black hole mergers and 1 binary neutron star merger announced so far, the Advanced LIGO and Virgo detectors have started their census of the local(ish) compact binary population. With detection rates as high as one per week in the next observing run, and one per day in the coming years, we will quickly accumulate the statistics necessary to constrain the physics relevant to binary formation. I will present some the techniques being developed to make these inferences, what we have learned so far, and what we might learn in the near future.

Hadronic corrections to the anomalous magnetic moment of the muon Dr. Peter Stoffer, University of California, San Diego INT Conference room C421

The anomalous magnetic moment of the muon g-2 has been measured and computed to very high precision of about 0.5 ppm. For more than a decade, a discrepancy has persisted between experiment and Standard Model prediction, now of about 3-4 sigma. The main uncertainty of the theory prediction is due to strong-interaction effects, the hadronic vacuum polarisation (HVP) and hadronic light-by-light (HLbL) contributions.

While the most precise HVP evaluation is based on dispersion relations and data input, HLbL is currently plagued by uncontrolled model uncertainties. Within a dispersive framework based on unitarity and analyticity, we scrutinize the uncertainty estimates for the two-pion HVP channel and we calculate model-independently two-pion contributions in HLbL, which shows an avenue towards a data-driven evaluation of g-2 of the muon.

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.