We present a search at the Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling α' to electrons. Such a particle A' can be produced in electron-nucleus ...fixed-target scattering and then decay to an e + e- pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175-250 MeV, found no evidence for an A'→ e+ e- reaction, and set an upper limit of α'/α ~/= 10(-6). Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces.
Two-phase noble liquid detectors, with large target masses and effective background reduction, are currently leading the dark matter direct detection for WIMP masses above a few GeV. Due to their ...sensitivity to single ionized electron signals, these detectors were shown to also have strong constraints for sub-GeV dark matter via their scattering on electrons. In fact, the most stringent direct detection constraints for sub-GeV dark matter down to as low as 5 MeV come from noble liquid detectors, namely XENON10, DarkSide-50, XENON100 and XENON1T, although these experiments still suffer from high background at single or a few electron level. LBECA is a planned 100-kg scale liquid xenon detector with significant reduction of the single and a few electron background. The experiment will improve the sensitivity to sub-GeV dark matter by three orders of magnitude compared to the current best constraints.
Investigation at a
φ
-factory can shed light on several debated issues in particle physics. We discuss: (i) recent theoretical development and experimental progress in kaon physics relevant for the ...Standard Model tests in the flavor sector, (ii) the sensitivity we can reach in probing CPT and Quantum Mechanics from time evolution of entangled-kaon states, (iii) the interest for improving on the present measurements of non-leptonic and radiative decays of kaons and
η
/
η
′ mesons, (iv) the contribution to understand the nature of light scalar mesons, and (v) the opportunity to search for narrow di-lepton resonances suggested by recent models proposing a hidden dark-matter sector. We also report on the
e
+
e
−
physics in the continuum with the measurements of (multi)hadronic cross sections and the study of
γ
γ
processes.
Abstract
The Dark Matter Daily Modulation experiment (DMSQUARE) seeks for dark matter interactions with a Skipper CCD. It is currently running at surface level in Bariloche, Argentina, and will be ...moved to a shallow underground site at Sierra Grande, Argentina in November 2021. The low threshold achieved by Skipper CCDs allows to search for electron recoil events with an ionization energy down to 1.2 eV. In order to extract a potential dark matter signal from noise at the single electron level, we propose to search for a diurnal modulation of events, resulting from the potential interaction of the dark matter wind with the particles in the Earth. Depending on the model, mass and cross-section, this modulation can be maximum at 40deg of latitude in the Southern Hemisphere, where DMSQUARE is operated. In this article we present the experiment, report preliminary results with a prototype Skipper CCD taking data at surface level and comment on future prospects.
Background: With communication skills deemed increasingly important for engineering graduates, we wanted to understand how writing is currently included in engineering classes, what challenges are ...caused by including writing in such classes, and what resources would be most useful to help engineering instructors more easily include writing in engineering classes. Literature review: Writing is a necessary skill for engineering graduates and has received increased attention in engineering classes. However, despite many instructors' beliefs that writing is an important skill for engineers, it is not typically taught in a systematic and comprehensive way across the engineering curriculum. Research questions: 1. What perceptions of writing, and specifically writing in engineering, do engineering instructors hold? 2. To what extent do engineering instructors report incorporation of writing activities and assignments in their classes? 3. What barriers do engineering instructors perceive as inhibiting the inclusion of more writing in engineering courses? 4. What resources do engineering instructors desire to expand and improve the inclusion of writing in engineering courses? Research methods: A survey was completed by engineering instructional staff (n = 190 respondents, 10.7% response rate) from seven institutions as well as by some members of the Big10+ Engineering Deans Mailing List. Instructors were asked about their general perceptions about writing in engineering and were also asked to consider the most recent engineering course that they taught and reflect on how they included (or did not include) writing in their course. Findings and conclusions: As expected, we found that most engineering instructional staff agree that writing skills are very important in engineering. Yet, we found that constraints on time and resources kept instructors from including more writing in their courses. This paper concludes with a discussion of our efforts to develop resources, such as rubrics, graded writing examples, and strategies for developing writing prompts, to help instructors include more writing in their engineering courses .
The dwarf spheroidal satellite galaxies (dSphs) of the Milky Way are some of the most dark matter (DM) dominated objects known. We report on γ-ray observations of Milky Way dSphs based on six years ...of Fermi Large Area Telescope data processed with the new Pass8 event-level analysis. None of the dSphs are significantly detected in γ rays, and we present upper limits on the DM annihilation cross section from a combined analysis of 15 dSphs. These constraints are among the strongest and most robust to date and lie below the canonical thermal relic cross section for DM of mass ≲100 GeV annihilating via quark and τ-lepton channels.
"Future Girls of STEM" is a university-sponsored, summer camp outreach program that was designed and implemented by an all-female faculty group to increase young girls' interest in pursuing future ...careers in science, technology, engineering, and mathematics (STEM). This paper discusses the logistics and results of the pilot Future Girls of STEM camp, which was held in the summer of 2019 for seven to twelve-year-old girls. The four-day summer camp featured female engineers from local industry, who shared personal stories of their careers and helped campers work through engineering and leadership activities. Researchers assessed whether completing the activities increased participants' understanding of, interest in, and self-efficacy in engineering topics, majors, and careers. Results showed an increased interest and self-reported understanding of engineering topics after participants completed the camp, as well as high self-efficacy throughout the camp experience. The Future Girls of STEM program, and its hands-on, interactive activities, can be transferred to other locations or universities with varying resources available.
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