Bulletin of the American Physical Society
APS April Meeting 2022
Volume 67, Number 6
Saturday–Tuesday, April 9–12, 2022; New York
Session S11: Mini-symposium: Neutrino Mass IIMini-Symposium Recordings Available
|
Hide Abstracts |
Sponsoring Units: DNP DAP DPF Chair: Jo Dunkley, Princeton University Room: Majestic |
Monday, April 11, 2022 1:30PM - 1:42PM |
S11.00001: Sterile neutrino decay during the weak decoupling epoch and its effects on the early Universe and Big Bang Nucleosynthesis Hannah Rasmussen, Alex McNichol, Chad T Kishimoto, George M Fuller The hot and dense early Universe combined with the promise of high-precision cosmological observations provide an intriguing laboratory for Beyond Standard Model (BSM) physics. We simulate the early Universe to examine the effects of the decay of thermally populated sterile neutrino states into Standard Model products around the time of weak decoupling. These decays deposit a significant amount of entropy into the plasma as well as produce a population of high-energy out-of-equilibrium active neutrinos. As a result, we can constrain these models by their inferred value of Neff, the effective number of relativistic degrees of freedom. In our work, we explore a variety of models with Neff values consistent with CMB observations, but with vastly different active neutrino spectra which will alter the time-temperature relation and lepton capture rates on free nucleons. We discuss how these effects of sterile neutrino decay challenge the standard cosmological model and affect Big Bang Nucleosynthesis (BBN). |
Monday, April 11, 2022 1:42PM - 1:54PM |
S11.00002: BBN and CMB combined and separate constraints on new physics: measuring Neff and probing its evolution in the early Universe Tsung-Han Yeh, Jessie Shelton, Keith A Olive, Brian D Fields Big Bang Nucleosynthesis (BBN) and the cosmic microwave background (CMB) both probe the physics of the early Universe. BBN accounts for the cosmic origin of the lightest elements, e.g., 2H and 4He. Having precisely measured nuclear data as inputs, BBN abundance calculation depends on two cosmological parameters: the cosmic baryon-to-photon ratio η = nb/nγ and the effective number of neutrino species Neff. BBN data analyses then use observed primordial abundances to determine η and Neff in return. The CMB can also independently determine both parameters. Hence, the BBN+CMB joint constraint on Neff provides a sharpened cosmological probe to new physics. Any departure from the Standard Model NeffSM would unveil nonstandard cosmology and likely BSM physics. Moreover, BBN+CMB constraints on new physics improve when newer precision observations are available. Latest developments of such joint analyses will be presented. In addition, both BBN and the CMB analyses independently reach levels of precision that can meaningfully probe changes in η and/or Neff between these two epochs. This open a new window to study a broad variety of BSM models, including extra entropy and/or radiation injection between BBN and the CMB. Likelihoods of (Δη, ΔNeff) from our latest research will be reported. |
Monday, April 11, 2022 1:54PM - 2:06PM |
S11.00003: Hidden-Sector Neutrinos and Freeze-In Leptogenesis Rafael W Porto, Ina C Flood, Jane F Schlesinger, Brian Y Shuve, Maxwell Thum Sterile neutrinos at the GeV scale can resolve several outstanding problems of the Standard Model (SM), such as the source of neutrino masses and the origin of the baryon asymmetry through freeze-in leptogenesis, but they can be challenging to detect experimentally due to their small couplings to SM particles. In extensions of the SM with new interactions of the sterile neutrinos, they can be produced copiously at accelerators and colliders. We systematically investigate the impact of such novel interactions on the asymmetry from freeze-in leptogenesis. We find that the interactions tend to bring the sterile neutrinos into equilibrium at early times, leading to a significant reduction in the generated asymmetry. We also show that observable rates of several hidden-sector neutrino signatures, such as SM Higgs decays to pairs of sterile neutrinos, can be inconsistent with the observed baryon asymmetry and provide an opportunity to falsify freeze-in leptogenesis. |
Monday, April 11, 2022 2:06PM - 2:18PM |
S11.00004: Cascade Appearance Signatures of Sterile Neutrinos at 1-100 TeV Benjamin Smithers, Benjamin J Jones, Janet M Conrad, Carlos A Arguelles, Alejandro Diaz Existing tensions and anomalies in neutrino oscillations data suggest the possibility of a fourth, non-active, neutrino. Such a `sterile' neutrino with eV2-scale mass-squared splittings would lead to resonant matter-enhanced oscillations for Earth-crossing atmospheric neutrinos; a signature for which km3-scale neutrino telescopes are distinctly well suited to study. In this talk, we explore the detectability of these signatures at such neutrino telescopes given present constraints on sterile neutrino mixing. As an example, we forecast the sensitivity of the IceCube Neutrino Observatory to the mixing angles θ14, θ24, and θ34 in the 3+1 sterile neutrino model using the cascade channel with ten years of data. We find that ντ appearance signatures consistent with the existing IceCube νμ disappearance best-fit point are discoverable for values of θ34 consistent with world constraints, and that the sterile neutrino parameters favored by the BEST and gallium anomalies are expected to be testable at the 95% confidence level. |
Monday, April 11, 2022 2:18PM - 2:30PM |
S11.00005: Classical and Quantum Coherent Neutrino Oscillations Joshua D Martin, Alessandro Roggero, Huaiyu Duan, Joseph A Carlson, Vincenzo Cirigliano Neutrinos are emitted in enormously large fluxes in extreme astrophysical environments such as core collapse supernovae, binary neutron star mergers and the early universe. Through coherent forward scattering, neutrinos traveling along different trajectories may exchange flavor information resulting in macroscopically large scale flavor oscillations. The Hamiltonian which governs the flavor content evolution in these dense neutrino gases in the two-flavor approximation can be written as a quantum spin-spin Hamiltonian similar to the Heisenberg model, but with all-to-all couplings in the two-body interaction. Solving the full quantum evolution in this system even for very simple initial conditions can be prohibitively difficult, and as such much of the investigation into the flavor dynamics present in such dense neutrino gases has been performed in the mean-field approximation. We examined the fully quantum evolution of a dense neutrino gas in a simple "two-beam" model under a product state prototypical initial condition. By exploiting the symmetries of this model, we are able to track the full coherent evolution of thousands of neutrino flavor spins, and make direct comparisons with two well understood flavor oscillation modes in the mean-field limit. In all cases we find that the mean-field well describes the evolution of simple one-body observables despite the presence and development of entanglement among the neutrinos in the two beams. |
Monday, April 11, 2022 2:30PM - 2:42PM |
S11.00006: PROSPECT-II Oscillation Physics Goals and Beyond Manoa Andriamirado The Precision Reactor Oscillation and SPECTrum, or PROSPECT, detector is designed to search for eV-scale sterile neutrino oscillation and to make a high resolution spectrum measurement. PROSPECT consists of a segment 6Li-doped liquid scintillator volume deployed at ~7m from the High Flux Isotope Reactor at Oak Ridge National Laboratory. Due to the degree of segmentation and the short baseline deployment, the PROSPECT detector is excellent to probe mass-splitting between 0.1-10 eV2. While PROSPECT has set stringent new limits on sterile neutrinos in this mass splitting range, physically relevant parameter space remains unaddressed. An evolutionary upgrade of PROSPECT detector is in progress that will provide an improved spectrum measurement and will significantly exceed the current sensitivity in oscillation parameter space. This talk will focus on PROSPECT-II oscillation sensitivity and the possible impact of additional future deployments. |
Monday, April 11, 2022 2:42PM - 2:54PM |
S11.00007: PROSPECT-II detector design and external calibration scheme Xiaobin Lu PROSPECT, the Precision Reactor Oscillation and SPECTrum Experiment, operates at very short baselines from the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory to make precision flux and energy spectral measurements of reactor antineutrinos. One of the goals of PROSPECT is to search for a signature of antineutrinos changing or oscillating into a sterile type of neutrino. In its first phase, PROSPECT-I produced some of the strongest limits on eV-scale sterile neutrinos, made a precision measurement of the reactor antineutrino spectrum from U-235, and demonstrated the observation of reactor antineutrinos in an aboveground detector with good energy resolution and well-controlled backgrounds. The PROSPECT collaboration is now preparing an upgraded detector, PROSPECT-II, to probe yet unexplored parameter space for sterile neutrinos and contribute to a full resolution of the Reactor Antineutrino Anomaly, a long-standing puzzle in neutrino physics. This talk will cover the detector improvements and provide details of a new external calibration scheme. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700