More Like this

1. Heavy neutral leptons at beam dump experiments of future lepton colliders

   https://doi.org/10.1007/JHEP04(2023)046  

   Giffin, Pierce ; Gori, Stefania ; Tsai, Yu-Dai ; Tuckler, Douglas ( April 2023 , Journal of High Energy Physics)

   A bstract A new beam dump experiment that utilizes the beam of future high energy electron-positron colliders could be an excellent avenue to search for dark sector particles due to its unprecedented high energy and intensity. We consider heavy neutral leptons (HNLs) as a specific example to demonstrate the sensitivity of searches for dark sector particles at future electron-positron collider beam dump experiments. This includes the study of the reach at the International Linear Collider (ILC), the Cool Copper Collider (C 3 ), and the Compact Linear Collider (CLIC). We comprehensively examine the HNL production and detector acceptance at these electron beam dump experiments. We show that these experiments will probe regions of HNL parameter space, not yet probed by past experiments, as well as by future approved experiments. Our study also motivates a more detailed analysis of heavy meson productions in high-energy electron-nucleon collisions in thick targets. 

   more » « less
2. The Complexity of Nonbinary Gender Inclusion in Engineering Culture

   Haverkamp, A. ( June 2018 , ASEE annual conference & exposition)

   Gender in engineering is a long-standing source of inquiry, research, outreach, and discussion as inequity in demographics and negative experiences persist in the field. Women consist of just approximately 20% of our engineering undergraduate programs nationally, and roughly 14% of our national professional workforce. Absent from these numbers and research into gender minority experiences are students who lay further on the margins of discussion, awareness, inclusion, and acknowledgement of existence - students who identify as nonbinary or other genders aside from man or woman. This paper presents background literature on gender, gender minority experiences in higher education, nonbinary gender identity, and aims to present points of discussion to facilitate further engagement with a more nuanced understanding of gender in engineering. Gender as a social system is defined by multiplicity and fluidity and does not fit within two unitary and discrete categories. The majority of current gender in engineering scholarship utilizes a conceptualization of gender which does not acknowledge or incorporate more than two gender options, and is rooted in increasingly rejected notions of biological essentialism. Nonbinary and gender nonconforming students, some of which also identify within the transgender population, exist in liminal spaces throughout society and higher education, and continuation of this scholarship tacitly denies their existence by framing gender as intrinsically linked to two biological categories. Engineering professionals, faculty, and students who identify as neither men nor women must be included and our conversation be expanded for academically rigorous investigation into gender dynamics and create inclusive engineering spaces. Conversations around gender neutral bathrooms are just the beginnings of widespread cultural change to support gender expansive engineers. The discipline must re-think our approaches towards gender equity in engineering and the theoretical conceptualization of gender to not only frame its inequity through the sharp underrepresentation of women, but its gender dynamics as experienced by nonbinary and gender nonconforming students. We must continue to make space for marginalized gender identities and gendered experiences. Through reviewing existing literature and integrating my own intimate experiences I seek to discuss preliminary efforts towards nonbinary inclusion in our teaching, professionalization, and language. This paper represents a point of entry for discussing nonbinary inclusion as part of the discipline's continued commitment to cultural change surrounding gender. 

   more » « less
3. The Complexity of Nonbinary Gender Inclusion in Engineering Culture

   Haverkamp, A. ( June 2018 , ASEE annual conference & exposition)

   Gender in engineering is a long-standing source of inquiry, research, outreach, and discussion as inequity in demographics and negative experiences persist in the field. Women consist of just approximately 20% of our engineering undergraduate programs nationally, and roughly 14% of our national professional workforce. Absent from these numbers and research into gender minority experiences are students who lay further on the margins of discussion, awareness, inclusion, and acknowledgement of existence - students who identify as nonbinary or other genders aside from man or woman. This paper presents background literature on gender, gender minority experiences in higher education, nonbinary gender identity, and aims to present points of discussion to facilitate further engagement with a more nuanced understanding of gender in engineering. Gender as a social system is defined by multiplicity and fluidity and does not fit within two unitary and discrete categories. The majority of current gender in engineering scholarship utilizes a conceptualization of gender which does not acknowledge or incorporate more than two gender options, and is rooted in increasingly rejected notions of biological essentialism. Nonbinary and gender nonconforming students, some of which also identify within the transgender population, exist in liminal spaces throughout society and higher education, and continuation of this scholarship tacitly denies their existence by framing gender as intrinsically linked to two biological categories. Engineering professionals, faculty, and students who identify as neither men nor women must be included and our conversation be expanded for academically rigorous investigation into gender dynamics and create inclusive engineering spaces. Conversations around gender neutral bathrooms are just the beginnings of widespread cultural change to support gender expansive engineers. The discipline must re-think our approaches towards gender equity in engineering and the theoretical conceptualization of gender to not only frame its inequity through the sharp underrepresentation of women, but its gender dynamics as experienced by nonbinary and gender nonconforming students. We must continue to make space for marginalized gender identities and gendered experiences. Through reviewing existing literature and integrating my own intimate experiences I seek to discuss preliminary efforts towards nonbinary inclusion in our teaching, professionalization, and language. This paper represents a point of entry for discussing nonbinary inclusion as part of the discipline's continued commitment to cultural change surrounding gender. 

   more » « less
4. A Mean-risk Mixed Integer Nonlinear Program for Network Protection

   https://doi.org/liojoin  

   Burton, Amy ( January 2020 , Thesis for Clemson University)

   d. Many of the infrastructure sectors that are considered to be crucial by the Department of Homeland Security include networked systems (physical and temporal) that function to move some commodity like electricity, people, or even communication from one location of importance to another. The costs associated with these flows make up the price of the network’s normal functionality. These networks have limited capacities, which cause the marginal cost of a unit of flow across an edge to increase as congestion builds. In order to limit the expense of a network’s normal demand we aim to increase the resilience of the system and specifically the resilience of the arc capacities. Divisions of critical infrastructure have faced difficulties in recent years as inadequate resources have been available for needed upgrades and repairs. Without being able to determine future factors that cause damage both minor and extreme to the networks, officials must decide how to best allocate the limited funds now so that these essential systems can withstand the heavy weight of society’s reliance. We model these resource allocation decisions using a two-stage stochastic program (SP) for the purpose of network protection. Starting with a general form for a basic two-stage SP, we enforce assumptions that specify characteristics key to this type of decision model. The second stage objective—which represents the price of the network’s routine functionality—is nonlinear, as it reflects the increasing marginal cost per unit of additional flow across an arc. After the model has been designed properly to reflect the network protection problem, we are left with a nonconvex, nonlinear, nonseparable risk-neutral program. This research focuses on key reformulation techniques that transform the problematic model into one that is convex, separable, and much more solvable. Our approach focuses on using perspective functions to convexify the feasibility set of the second stage and second order conic constraints to represent nonlinear constraints in a form that better allows the use of computational solvers. Once these methods have been applied to the risk-neutral model we introduce a risk measure into the first stage that allows us to control the balance between an efficient, solvable model and the need to hedge against extreme events. Using Benders cuts that exploit linear separability, we give a decomposition and solution algorithm for the general network model. The innovations included in this formulation are then implemented on a transportation network with given flow demand 

   more » « less
5. Heavy neutral leptons at the Electron-Ion Collider

   https://doi.org/10.1007/JHEP03(2023)020  

   Batell, Brian ; Ghosh, Tathagata ; Han, Tao ; Xie, Keping ( March 2023 , Journal of High Energy Physics)

   A bstract The future Electron-Ion Collider (EIC) at Brookhaven National Laboratory, along with its primary capacity to elucidate the nuclear structure, will offer new opportunities to probe physics beyond the Standard Model coupled to the electroweak sector. Among the best motivated examples of such new physics are new heavy neutral leptons (HNLs), which are likely to play a key role in neutrino mass generation and lepton number violation. We study the capability of the EIC to search for HNLs, which can be produced in electron- proton collisions through charged current interactions as a consequence of their mixing with light neutrinos. We find that, with the EIC design energy and integrated luminosity, one is able to probe HNLs in the mass range of 1 – 100 GeV with mixing angles down to the order of 10 − 4 − 10 − 3 through the prompt decay signatures, and in the mass range of 1 10 GeV with | U e | 2 ~ 10 − 6 – 10 − 4 via the displaced decay signatures. We also consider the invisible mode where an HNL is undetected or decaying to dark sector particles. One could potentially probe heavy HNLs for mixing angles in the window 10 − 3 – 10 − 2 , provided SM background systematics can be brought under control. These searches are complementary to other probes of HNLs, such as neutrino-less double- β decay, meson decay, fixed-target, and high-energy collider experiments. 

   more » « less