The search for dark matter holds considerable interest in the physics community. Any laboratory-based evidence of Beyond the Standard Model physics would begin to illuminate the dark sector. Many experiments have searched for such evidence, but so far it has proven elusive. For the nuclear physics community the concept of a low mass dark photon has garnered considerable attention. Of particular recent interest are the well-known g_{\mu}-2 anomaly and an excess observed in the decay of excited states of He-4, Be-8 and C-12, which could be explained by a 17 MeV/c² mass dark boson. The proposed DarkLight experiment would search for this potential low mass force carrier at the TRIUMF ARIEL accelerator in the 10-20 MeV/c² e⁺e^- invariant mass range. This talk will focus on the motivation, physics case, and experimental design of the DarkLight experiment.
 

We present the nucleon vector form factors in a convenient parametric form that is optimized for low momentum transfers < few GeV^2. The form factors are determined from a global fit to electron scattering data and precise charge radii measurements with an updated treatment of radiative corrections. We evaluate the unpolarized charged-current elastic neutrino–nucleon scattering cross sections at GeV energies of neutrino oscillation experiments. These cross sections differ by 3–5% compared to commonly used form-factor models. Contrary to these models, our form factors are constrained by recent high-statistics electron–proton scattering data from the A1 Collaboration. We also implement updated nucleon vector form factors in the neutrino event generator GENIE. On top of the form-factor description at leading order, radiative corrections in the Standard Model and potential new physics generate additional contributions. We provide a general framework of invariant amplitudes and explore the impact of modern and future cross section measurements, considering both unpolarized cross sections and polarization observables, on constraining these amplitudes. We also discuss the effects of radiative corrections on the unpolarized cross section and all possible single-spin asymmetries.

Pulsars have become fertile ground for unraveling the mysteries of fundamental physics. Among the many intriguing avenues of exploration is the consideration of baryon number violation (BNV), a phenomenon linked to questions such as the baryon asymmetry problem. Stringent constraints on BNV result from its lack of observation in experiments, making the search for its consequences in astrophysical environments a natural step to explore. In this presentation, we delve into the effects of a particular class of slow BNV, one that leads to quasi-equilibrium evolutions, on the spin parameters of pulsars. These parameters encompass vital characteristics such as spin-down rates, the second derivative of frequency, and pulsar braking indices. Within pulsars, the existence of BNV may manifest as anomalies in the second derivative of pulsar spin frequency, transitions between states of spinning down and spinning up, and it can give rise to a diverse range of both positive and negative braking indices. We explore the prospects of detecting these effects in the wake of the recent discovery of a stochastic gravitational wave background by NANOGrav.

For a quantitative investigation on the time evolution of heavy thermal dark matter particles at and after thermal freeze-out, close-to-threshold processes need to be taken into account which have a large impact on the observed dark matter relic abundance.  Our aim is to study the recoil effect of kinetically equilibrated dark matter pairs in a thermal medium and compute the center-of-mass recoil corrections to the near-threshold observables in the laboratory frame within the framework of potential non-relativistic effective field theories at finite temperature.  For the considered hierarchy of energy scales, we highlight the relative corrections due the recoil on the present dark matter energy density.

Among the four known fundamental forces or interactions, gravitation and electromagnetism are close to daily life, while the strong and weak forces only reveal themselves at sub-atomic or smaller scales. The strong force, which is mediated by gluon exchange between quarks confines quarks into protons and neutrons (nucleons). The residual component of this strong force that induces the strong nuclear interactions between nucleons at the fermi scale (10^-15m). This so-called "nuclear force" is attractive at a longer distance (e.g. for nucleon separation greater than the proton radius) and binds nucleons together into nuclei), while the force is strongly repulsive at a much shorter distance which prevents the nucleus from collapsing. 
Nucleon interactions at short distances are not well-described in either QCD or the field theory. Experimentally, a series of electron-nucleon scattering measurements at Jefferson Lab (JLab) have determined about 20% of nucleons in heavy nuclei are moving fast (above the Fermi momentum) due to hard, short-distance interactions with another nucleons, forming so-called short-range correlated (SRC) pairs. Understanding those SRC pairs is necessary in providing a complete  description of nuclear structure. It also offers us a unique chance to probe the tensor and repulsive force at intermediate to short distances. In this talk, I will present recent results from the JLab Hall A tritium program which studied the momentum distribution, and spin/isospin structure of SRC pairs in the mirror nuclei tritium and helium-3. I will then discuss how those measurements help us better understand the short-distance part of strong nucleon-nucleon interactions, and their connections to future experiments.

The axion is one of the best motivated dark matter candidates, simultaneously solving the Strong CP problem as well as providing the dark matter of the universe. However, in comparison to WIMPs the axion was historically neglected by experimental efforts. This has been changing in the last five years, which a bevy of new experiment proposals and results. I outline several recent updates for new detection ideas, including plasma haloscopes and axion detection with phonon-polaritons.

The Short-Baseline Near Detector (SBND) sits in an intense stream of neutrinos from the Booster Neutrino Beam at Fermilab. With only 110 m between the detector volume and the beam target, SBND will have unprecedented statistics of over a million neutrino interactions per year, allowing for precise cross-section measurements and Beyond the Standard Model physics searches. Importantly, SBND is the near detector of the Short-Baseline Neutrino (SBN) program which will allow the study of neutrino oscillations with much greater statistics capabilities than have been previously possible. SBND is a 112-ton active volume Liquid Argon Time Projection Chamber (LArTPC) neutrino detector and it is anticipated to start operations in late 2023. This seminar will focus on the recent progress in construction and commissioning as well as novel analysis tools and the physics which SBND is expected to probe.

Although the existence of neutrino mass is firmly established, the precise neutrino mass scale remains unknown.  To directly probe this property, measurements of the endpoint of the tritium beta spectrum have achieved the greatest sensitivity, recently reaching the sub-eV scale.  In this talk, I will present Project 8, an experimental concept based on the novel Cyclotron Radiation Emission Spectroscopy (CRES) technique.  Project 8 has recently released its first measurements of the tritium beta spectral endpoint and demonstrated its high precision spectroscopy using krypton calibration.  An R&D campaign is now underway to demonstrate scalability of the CRES technique and to develop the atomic tritium source required.  Building on these successes, a next-generation experiment is envisioned with neutrino mass sensitivity down to 40 meV.

Abstract:  In April 2021, the Muon g-2 Experiment at Fermilab reported its first measurement of the muon magnetic anomaly to an unprecedented precision of 460 ppb. The result agrees with the previous measurement performed at Brookhaven National Laboratory, and the combined experimental value is in tension with the Standard Model prediction at 4.2 sigma, a possible hint of new physics. The first result from the Fermilab experiment was based on its Run-1 data, collected in 2018, which comprises just 6% of the experiment’s target statistics. The Runs 2 & 3 data, collected between 2019-2020, amount to a four-fold increase in statistics and consequently, a factor of two reduction in the statistical uncertainty. The measurement relies on the precise determination of two key quantities: the anomalous precession frequency of the muon and the magnetic field. In this seminar, I will describe the Fermilab experiment with a focus on the anomalous precession frequency analysis of the Run-2 and Run-3 data. I detail the procedures used, highlighting improvements compared to the Run-1 analysis. I also show blinded results and discuss some of the largest systematic uncertainties in the analysis, as well as provide an outlook and current status of the experiment.