Experimental Search for Neutron to Mirror Neutron Oscillations as an Explanation of the Neutron Lifetime Anomaly

An unexplained $>4\,\sigma$ discrepancy persists between "beam" and "bottle" measurements of the neutron lifetime. A new model proposed that conversions of neutrons $n$ into mirror neutrons $n'$, part of a dark mirror sector, can increase the apparent neutron lifetime by $1\%$ via a small mass splitting $\Delta{m}$ between $n$ and $n'$ inside the 4.6 T magnetic field of the National Institute of Standards and Technology Beam Lifetime experiment. A search for neutron conversions in a 6.6 T magnetic field was performed at the Spallation Neutron Source which excludes this explanation for the neutron lifetime discrepancy

The Beta-decay Paul Trap Mk IV: Design and commissioning

The Beta-decay Paul Trap is an open-geometry, linear trap used to measure the decays of $^8$Li and $^8$B to search for a tensor contribution to the weak interaction. In the latest $^8$Li measurement of Burkey et al. (2022), $\beta$ scattering was the dominant experimental systematic uncertainty. The Beta-decay Paul Trap Mk IV reduces the prevalence of $\beta$ scattering by a factor of 4 through a redesigned electrode geometry and the use of glassy carbon and graphite as electrode materials. The trap has been constructed and successfully commissioned with $^8$Li in a new data campaign that collected 2.6 million triple coincidence events, an increase in statistics by 30% with 4 times less $\beta$ scattering compared to the previous $^8$Li data set.Comment: 17 pages, 7 figure

New high-sensitivity searches for neutrons converting into antineutrons and/or sterile neutrons at the HIBEAM/NNBAR experiment at the European Spallation Source

The violation of baryon number, B, is an essential ingredient for the preferential creation of matter over antimatter needed to account for the observed baryon asymmetry in the Universe. However, such a process has yet to be experimentally observed. The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source to search for baryon number violation. The program will include high-sensitivity searches for processes that violate baryon number by one or two units: free neutron-antineutron oscillation (n -> (n) over bar) via mixing, neutron-antineutron oscillation via regeneration from a sterile neutron state (n -> [n',(n) over bar'] -> (n) over bar), and neutron disappearance (n -> n'); the effective Delta B = 0 process of neutron regeneration (n ->[n',(n) over bar'] -> n) is also possible. The program can be used to discover and characterize mixing in the neutron, antineutron and sterile neutron sectors. The experiment addresses topical open questions such as the origins of baryogenesis and the nature of dark matter, and is sensitive to scales of new physics substantially in excess of those available at colliders. A goal of the program is to open a discovery window to neutron conversion probabilities (sensitivities) by up to three orders of magnitude compared with previous searches. The opportunity to make such a leap in sensitivity tests should not be squandered. The experiment pulls together a diverse international team of physicists from the particle (collider and low energy) and nuclear physics communities, while also including specialists in neutronics and magnetics.Peer reviewe

Fundamental Symmetries, Neutrons, and Neutrinos (FSNN): Whitepaper for the 2023 NSAC Long Range Plan

This whitepaper presents the research priorities decided on by attendees of the 2022 Town Meeting for Fundamental Symmetries, Neutrons and Neutrinos, which took place December 13-15, 2022 in Chapel Hill, NC, as part of the Nuclear Science Advisory Committee (NSAC) 2023 Long Range Planning process. A total of 275 scientists registered for the meeting. The whitepaper makes a number of explicit recommendations and justifies them in detail

Transfer of nitrogen by migratory birds in the African-Western Eurasian Flyways

Migrating animals are known to play an important role in nutrient transfer over short distances; however, this phenomenon has not been well studied for long-distance migrants. In this preliminary study, we focused on nitrogen (N) transfer by 44 bird species that migrate from Eurasia to two regions in sub-Saharan Africa that fall into the lowest 10% quantile of global N-deposition (mean annual deposition ≤ 10.44 mg/m2/year). We estimated the number of birds that die during the non-breeding season in these areas and then used N content and species-specific mass values to calculate annual N-deposition rates. For these two areas of low N-deposition, we found that bird mortality contributed 0.2 – 1.1% of total nitrogen deposition, which is a relatively small proportion. Therefore, we conclude that nitrogen transfer by long-distance bird migrants using the East Atlantic Flyway and the West Asian-East African Flyway currently has limited impact on the sub-Saharan nitrogen cycle. However, it is worth noting that this impact may have been more important in the past due to larger bird populations and lower background N-deposition (i.e., less anthropogenic impact)

Bacterial biofilm formation in the urinary bladder of spinal cord injured patients

In a randomized, double blind study, 145 HIV+ women receiving anti-retroviral therapy at Sekou-Toure Regional Hospital in Mwanza, Tanzania were enrolled. Participants were randomly allocated to receive 125 mL daily regular yogurt or 125 mL probiotic supplemented yogurt for 29 days. Subject interviews at day 0 and 29 revealed fewer vaginal symptoms and signs, better appetite, less stomach gas and more energy for work, irrespective of the treatment group. The Nugent scoring showed almost 40% women had improved vaginal microbiota over the month, albeit the addition of the probiotic did not differ from the standard yogurt group. Therefore, yogurt provides a safe nutritious food that can be made locally and taken daily by HIV-subjects receiving anti-retroviral therapy. It has the potential to transfer health benefits to the gut and vagina, but the extent to which a probiotic can add to this through rectal to perineal transfer remains to be determined. © 2011 Elsevier Ltd