Physics Commons^™

Search For Dark Matter Particles In Proton-Proton Collisions At √S=8 Tev Using The Razor Variables, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search for dark matter particles directly produced in proton-proton collisions recorded by the CMS experiment at the LHC is presented. The data correspond to an integrated luminosity of 18.8 fb−1, at a center-of-mass energy of 8 TeV. The event selection requires at least two jets and no isolated leptons. The razor variables are used to quantify the transverse momentum balance in the jet momenta. The study is performed separately for events with and without jets originating from b quarks. The observed yields are consistent with the expected backgrounds and, depending on the nature of the production mechanism, dark matter …

Effect Of Disorder On The Magnetic And Electronic Structure Of A Prospective Spin-Gapless Semiconductor Mncrval, P. Kharel, J. Herran, Pavel Lukashev, Y. Jin, J. Waybright, S. Gilbert, B, Staten, P. Gray, S. Valloppilly, Y. Huh, D. J. Sellmyer

Faculty Work

Recent discovery of a new class of materials, spin-gapless semiconductors (SGS), has attracted considerable attention in the last few years, primarily due to potential applications in the emerging field of spin-based electronics (spintronics). Here, we investigate structural, electronic, and magnetic properties of one potential SGS compound, MnCrVAl, using various experimental and theoretical techniques. Our calculations show that this material exhibits ≈ 0.5 eV band gap for the majority-spin states, while for the minority-spin it is nearly gapless. The calculated magnetic moment for the completely ordered structure is 2.9 µ_B/f.u., which is different from our experimentally measured value of …

Novel Concepts In Semiconductor Disk Lasers, Zhou Yang

Optical Science and Engineering ETDs

Optically-pumped semiconductor disk lasers (SDLs) have received much attention in recent years for a myriad of applications requiring intracavity access, good beam quality, wavelength versatility, and high output powers. The traditional scheme of these lasers feature a semiconductor distributed Bragg reflector (DBR) integrated with the active region, together forming an active mirror in an external free-space cavity. The active mirror component is fabricated by either epitaxial growth or post-growth processing. This places certain restrictions on SDL design, as material system choices become limited. It further viii hinders laser performance with regard to its thermal management and laser bandwidth (tuning range). …

Efficient And Robust Methods For Quantum Tomography, Charles Baldwin

Physics & Astronomy ETDs

The development of large-scale platforms that implement quantum information processing protocols requires new methods for verification and validation of quantum behavior. Quantum tomography (QT) is the standard tool for diagnosing quantum states, process, and readout devices by providing complete information about each. However, QT is limited since it is expensive to not only implement experimentally, but also requires heavy classical post-processing of experimental data. In this dissertation, we introduce new methods for QT that are more efficient to implement and robust to noise and errors, thereby making QT a more widely practical tool for current quantum information experiments. The crucial …

Spectroscopic And Spectro-Astrometric Analysis Of T Tauri Stars, Logan Ryan Brown

Dissertations

To understand our own solar origins, we must investigate the composition of the protoplanetary disk from which the solar system formed. To infer this, we study analogs to the early solar system called T Tauri stars. These objects are low-mass, pre-main sequence stars surrounded by circumstellar disks of material from which planets are believed to form. We present high-resolution, near-infrared spectroscopic data for the T Tauri stars DR Tau and AA Tau using NIRSPEC at the Keck II telescope. For DR Tau, a spectro-astrometric analysis was performed, obtaining sub-seeing spatial information on water emission. Alongside a disk model, we constrained …

Single Particle Tracking: Analysis Techniques For Live Cell Nanoscopy., Peter K. Relich

Physics & Astronomy ETDs

Single molecule experiments are a set of experiments designed specifically to study the properties of individual molecules. It has only been in the last three decades where single molecule experiments have been applied to the life sciences; where they have been successfully implemented in systems biology for probing the behaviors of sub-cellular mechanisms. The advent and growth of super-resolution techniques in single molecule experiments has made the fundamental behaviors of light and the associated nano-probes a necessary concern among life scientists wishing to advance the state of human knowledge in biology. This dissertation disseminates some of the practices learned in …

Search For Dark Matter In Proton-Proton Collisions At 8 Tev With Missing Transverse Momentum And Vector Boson Tagged Jets, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search is presented for an excess of events with large missing transverse momentum in association with at least one highly energetic jet, in a data sample of proton-proton collisions at a centre-of-mass energy of 8 TeV. The data correspond to an integrated luminosity of 19.7 fb−1 collected by the CMS experiment at the LHC. The results are interpreted using a set of simplified models for the production of dark matter via a scalar, pseudoscalar, vector, or axial vector mediator. Additional sensitivity is achieved by tagging events consistent with the jets originating from a hadronically decaying vector boson. This search …

Modern Assessment Of The High-Energy Background Environment At Small Atmospheric Depths Using The X-Calibur X-Ray Polarimeter And Its Implications, Rashied Baradaran Amini

Arts & Sciences Graduate Student Theses and Dissertations

Since the discovery of cosmic rays, Earth's upper atmosphere at depths of 1-10 g cm2 has been used for balloon-borne observations probing the high-energy universe. However, the interaction of cosmic rays with the earth atmosphere generates numerous particles, each with their own flux and interaction physics that contribute to instrument background. In Fall 2014, the X-Calibur X-ray polarimeter designed and built at Washington University in St. Louis was launched from Ft. Sumner, New Mexico. While no astrophysical observation was performed as a result of a failure in telescope mechanisms, X-Calibur was able to record hours of instrument background with an …

Scatterometry Of 50 Nm Half Pitch Features, Ruichao Zhu

Optical Science and Engineering ETDs

Metrology technologies are an essential adjunct to Integrated Circuit (I.C.) Semiconductor manufacturing. Scatterometry, an optical metrology, was chosen to measure 50 nm half pitch feature structures. A bread-board scatterometry system has been assembled to provide a non-contact, non-destructive, accurate and flexible measurement. A real-time, on-line scatterometry system has also been demonstrated and proven to provide a high throughput measurement.

Three different types of samples have been measured using the scatterometry setup. The wire-grid polarizer (WGP) sample has been made by Jet and Flash Nanoimprint Lithography with ~100 nm pitch and ~50 nm wide ~200 nm tall Al gratings on fused …

The Second Quantized Approach To The Study Of Model Hamiltonians In Quantum Hall Regime, Li Chen

Arts & Sciences Graduate Student Theses and Dissertations

The study of model Hamiltonians, whose exact ground states are well known quantum Hall states, have been investigated solely in the literature from the point of view of first quantized approach in the last few decades. However, a second quantized approach to such Hamiltonians has not been taken in the same measure. In this dissertation, we study Haldane pseudopotential, which is the parent Hamiltonian of 1/M Laughlin state, and Trugman-Kivelson pseudopotential, which is the parent Hamiltonian of 2/5 unprojected Jain state. We find that the study of these Hamiltonians in their second quantized forms not only reproduces all properties of …

New Techniques And Optimizations Of Short Echo-Time 1h Mri With Applications In Murine Lung, Jinbang Guo

Arts & Sciences Graduate Student Theses and Dissertations

Although x-ray computed tomography (CT) is a gold standard for pulmonary imaging, it has high ionizing radiation, which puts patients at greater risk of cancer, particularly in a longitudinal study with cumulative doses. Magnetic resonance imaging (MRI) doesn't involve exposure to ionizing radiation and is especially useful for visualizing soft tissues and organs such as ligaments, cartilage, brain, and heart. Many efforts have been made to apply MRI to study lung function and structure of both humans and animals. However, lung is a unique organ and is very different from other solid organs like the heart and brain due to …

The Dynamic Brain In Action: Cortical Oscillations And Coordination Dynamics, Mahmood Hoseini

Arts & Sciences Graduate Student Theses and Dissertations

Cortical oscillations are electrical activities with rhythmic and/or repetitive nature generated spontaneously and in response to stimuli. Study of cortical oscillations has become an area of converging interests since the last two decades and has deepened our understanding of its physiological basis across different behavioral states. Experimental and modeling work has taught us that there is a wide diversity of cellular and circuit mechanisms underlying the generation of cortical rhythms. A wildly diverse set of functions has pertained to synchronous oscillations but their significance in cognition should be better appraised in the more general framework of correlation between spike times …

Ongoing And Visually-Evoked Cortical Activity Measured Across Multiple Spatial Scales, Nathaniel Caleb Wright

Arts & Sciences Graduate Student Theses and Dissertations

The visual cortex is a densely-interconnected network of neurons, which receives sensory input from the early visual pathway, and represents information about the visual world in the resulting spatiotemporal activity patterns. These patterns are mediated by cortical interactions that span multiple spatial scales (i.e., neuron-neuron, neuron-population, and population-population). Such interactions are a fundamental property of cortical function, and capture the contribution of the cortex to sensory coding. Yet these interactions are only beginning to be understood, in part because of the challenge of recording ongoing and visually-evoked activity across multiple spatial scales in individual studies. In this thesis, we present …

Real-Space Mean-Field Theory Of A Spin-1 Bose Gas In Synthetic Dimensions, Hilary M. Hurst, Justin H. Wilson, J. H. Pixley, I. B. Spielman, Stefan S. Natu

Faculty Research, Scholarly, and Creative Activity

The internal degrees of freedom provided by ultracold atoms give a route for realizing higher dimensional physics in systems with limited spatial dimensions. Non-spatial degrees of freedom in these systems are dubbed "synthetic dimensions". This connection is useful from an experimental standpoint but complicated by the fact that interactions alter the condensate ground state. Here we use the Gross-Pitaevskii equation to study ground state properties of a spin-1 Bose gas under the combined influence of an optical lattice, spin-orbit coupling, and interactions at the mean field level. The associated phases depend on the sign of the spin-dependent interaction parameter and …

How Shape Of Simulated Graphene Sheets Affects Debye Scattering Patterns, Lindsay Lesh

Honors Projects

This research is about understanding the structure of a subset of graphitic stardust found in primitive meteorites (e.g. the Murchison meteorite). The carbon grains of interest exhibit a core-rim structure, where the core – with a density less than that of the graphitic rim – comprises the majority of the grain. Previous studies have shown that the cores are comprised primarily of unlayered graphene, and it has been hypothesized that the cores are the result of the rapid freezing (quenching) of a liquid carbon droplet. Electron diffraction is sensitive to small differences in crystal structure and simulated electron diffraction powder …

Sdss-Iv Manga – The Spatially Resolved Transition From Star Formation To Quiescence, Francesco Belfiore, Roberto Maiolino, Claudia Maraston, Eric Emsellem, Matthew A. Bershady, Karen L. Masters, Dmitry Bizyaev, Médéric Boquien, Joel R. Brownstein, Kevin Bundy, Aleksandar M. Diamond-Stanic, Niv Drory, Timothy M. Heckman, David R. Law, Olena Malanushenko, Audrey Oravetz, Kaike Pan, Alexandre Roman-Lopes, Daniel Thomas, Anne-Marie Weijmans, Kyle B. Westfall, Renbin Yan

Physics and Astronomy Faculty Publications

Using spatially resolved spectroscopy from SDSS-IV MaNGA we have demonstrated that low ionization emission-line regions (LIERs) in local galaxies result from photoionization by hot evolved stars, not active galactic nuclei, hence tracing galactic region hosting old stellar population where, despite the presence of ionized gas, star formation is no longer occurring. LIERs are ubiquitous in both quiescent galaxies and in the central regions of galaxies where star formation takes place at larger radii. We refer to these two classes of galaxies as extended LIER (eLIER) and central LIER (cLIER) galaxies, respectively. cLIERs are late-type galaxies primarily spread across the green …

Studies Of Inclusive Four-Jet Production With Two B-Tagged Jets In Proton-Proton Collisions At 7 Tev, V. Khachatryan, A. M. Sirunyan, A. R. Tumasyan, Marc M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, Daniel Noonan, Tuhin S. Roy, Francisco X. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

Measurements are presented of the cross section for the production of at least four jets, of which at least two originate from b quarks, in proton-proton collisions. Data collected with the CMS detector at the LHC at a center-of-mass energy of 7 TeV are used, corresponding to an integrated luminosity of 3 pb-1. The cross section is measured as a function of the jet transverse momentum for pT>20 GeV, and of the jet pseudorapidity for |η|<2.4 (b jets), 4.7 (untagged jets). The correlations in azimuthal angle and pT between the jets are also studied. The inclusive cross section is measured to be σ(pp→2b+2j+X)=69±3(stat)±24(syst) nb. The η and pT distributions of the four jets and the correlations between them are well reproduced by event generators that combine perturbative QCD calculations at next-to-leading-order accuracy with contributions from parton showers and multiparton interactions. © 2016 CERN.

Graphene Kirigami And Its Use In Biocompatible Strain Sensor, Erik Vyhmeister

Honors Theses

Graphene's large fracture strain (>30%), chemical inertness, and piezoresistive nature make it well suited for use as a biocompatible strain sensor. A rectangular multilayer strucutre with graphene as its operative component was designed. It consists of a bottom layer of SU-8, a center layer of graphene, and a top layer of SU-8 and gold, with gold acting as the electrical contact. Kirigami-style patterning is applied via photolithography and oxygen plasma etching, allowing for a greater fracture strain. Additionally, the kirigami affects the stress concentraton in the graphene, affecting its piezoresistive gauge factor. The complete (patterned) structure exhibited a fracture …

Search For Long-Lived Charged Particles In Proton-Proton Collisions At √S = 13 Tev, V. Khachatryan, A. M. Sirunyan, A. R. Tumasyan, Marc M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, Daniel Noonan, Tuhin S. Roy, Francisco X. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

Results are presented of a search for heavy stable charged particles produced in proton-proton collisions at √s = 13 TeV using a data sample corresponding to an integrated luminosity of 2.5 fb-1 collected in 2015 with the CMS detector at the CERN LHC. The search is conducted using signatures of anomalously high energy deposits in the silicon tracker and long time-of-flight measurements by the muon system. The data are consistent with the expected background, and upper limits are set on the cross sections for production of long-lived gluinos, top squarks, tau sleptons, and leptonlike long-lived fermions. These upper limits are …

Linear Feedback Stabilization For A Continuously Monitored Qubit, Taylor Lee Patti, A. Chantasri, Justin Dressel, A. N. Jordan

Student Scholar Symposium Abstracts and Posters

In quantum mechanics, standard or strong measurement approaches generally result in the collapse of an ensemble of wavefunctions into a stochastic mixture of eigenstates. On the other hand, continuous or weak measurements have the propensity to dynamically control the evolution of quantum states over time, guiding the trajectory of the state into non-trivial superpositions and maintaining state purity. This kind of measurement-induced state steering is of great theoretical and experimental interest for the harnessing of quantum bits or "qubits", which are the fundamental unit of the emerging quantum computer. We explore continuous measurement-based quantum state stabilization through linear feedback control …

Memory Effects In Brownian Motion, Random Walks Under Confining Potentials, And Relaxation Of Quantum Systems, Matthew Chase

Physics & Astronomy ETDs

This dissertation is a report on a number of distinct topics in the field of non-equilibrium statistical mechanics including the evolution of classical as well as quantum systems.

The evolution of an object that is described by the Ornstein-Uhlenbeck process generalized through a time-nonlocal attraction is considered. The time-nonlocality is taken to be represented in the Langevin description through the presence of memory. Analysis of the Langevin equation is performed for algebraic and delay-type memories. An equivalent \emph{bona-fide} Fokker-Planck equation is constructed.

A random walker subjected to a non-standard confining potential, taken to be a piece-wise linear function, is analyzed. …

Search For New Physics In Final States With Two Opposite-Sign, Same-Flavor Leptons, Jets, And Missing Transverse Momentum In Pp Collisions At √S = 13 Tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search is presented for physics beyond the standard model in final states with two opposite-sign, same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 2.3 fb−1 of proton-proton collisions at s=13 TeV collected with the CMS detector at the LHC in 2015. The analysis uses the invariant mass of the lepton pair, searching for a kinematic edge or a resonant-like excess compatible with the Z boson mass. Both search modes use several event categories in order to increase the sensitivity to new physics. These categories are based on the rapidity of the …

The Subject Librarian Newsletter, Physics, Fall 2016, Sandy Avila

Libraries' Newsletters

No abstract provided.

De Haas-Van Alphen Study Of Role Of 4f Electrons In Antiferromagnetic Cezn₁₁ As Compared To Its Nonmagnetic Analog Lazn₁₁, S. F. Blake, Halyna Hodovanets, A. Mccollam, S. L. Bud'ko, P. C. Canfield, A. I. Coldea

Physics Faculty Research & Creative Works

We present a de Haas-van Alphen study of the Fermi surface of the low-temperature antiferromagnet CeZn₁₁ and its nonmagnetic analog LaZn₁₁, measured by torque magnetometry up to fields of 33T and at temperatures down to 320mK. Both systems possess similar de Haas-van Alphen frequencies, with three clear sets of features -- ranging from 50T to 4kT -- corresponding to three bands of a complex Fermi surface, with an expected fourth band also seen weakly in CeZn₁₁. The effective masses of the charge carriers are very light ( < 1m_e) in LaZn₁₁ but a factor …

Structural Reinforcement Through Liquid Encapsulation, Alin Cristian Chipara, Peter Samora Owuor, Sanjit Bhowmick, Gustavo Brunetto, S. A. Syed Asif, Mircea Chipara, Robert Vajtai, Jun Lou, Douglas S. Galvao, Chandra Sekhar Tiwary

Physics & Astronomy Faculty Publications

The liquid inside a solid material is one of the most common composite materials in nature. The interface between solid–liquid plays an important role in unique deformation. Here, model systems of two polymers (polydimethylsiloxane–polyvinylidenefluoride) are used to make sphere of solid with liquid inside it.

Effects Of Time And Diffusion Phase-Lags In A Thick Circular Plate Due To A Ring Load With Axisymmetric Heat Supply, R. Kumar, N. Sharma, P. Lata

Applications and Applied Mathematics: An International Journal (AAM)

The purpose of this paper is to depict the effect of time, thermal, and diffusion phase lags due to axisymmetric heat supply in a ring. The problem is discussed within the context of DPLT and DPLD models. The upper and lower surfaces of the ring are traction-free and subjected to an axisymmetric heat supply. The solution is found by using Laplace and Hankel transform techniques. The analytical expressions of displacements, stresses and chemical potential, temperature and mass concentration are computed in transformed domain. Numerical inversion technique has been applied to obtain the results in the physical domain. Numerically simulated results …

Dispersion Characteristics Of Non-Newtonian Fluid During Transportation Of Nanoparticles In Permeable Capillary, Rekha Bali, Nivedita Gupta, Swati Mishra

Applications and Applied Mathematics: An International Journal (AAM)

The present analysis deals with the dispersion characteristics of blood described as Herschel- Bulkley fluid in capillary with permeable walls for fluid and impermeable for the nanoparticles. The contribution of molecular and convective diffusion is recalled from the Taylor and Aris coefficient of diffusion. The effective longitudinal diffusion depends on three parameters namely rheological parameter, pressure parameter, and the permeability parameter. We investigate the influence of the longitudinal transport of nanoparticles with permeable blood vessels on the effective dispersion. It shows that the effective diffusion of nanoparticles reduces with increase in radius of the plug region (i.e., the volume of …

A Generalized Polynomial Identity Arising From Quantum Mechanics, Shashikant B. Mulay, John J. Quinn, Mark A. Shattuck

Applications and Applied Mathematics: An International Journal (AAM)

We establish a general identity that expresses a Pfaffian of a certain matrix as a quotient of homogeneous polynomials. This identity arises in the study of weakly interacting many-body systems and its proof provides another way of realizing the equivalence of two proposed types of trial wave functions used to describe such systems. In the proof of our identity, we make use of only elementary linear algebra and combinatorics and thereby avoid use of more advanced conformal field theory in establishing the aforementioned equivalence.

On Arresting The Complex Growth Rates In Rotatory Triply Diffusive Convection, Jyoti Prakash, Renu Bala, Kanu Vaid, Vinod Kumar

Applications and Applied Mathematics: An International Journal (AAM)

Linear stability of a triply diffusive fluid layer (one of the components may be heat) has been mathematically analyzed in the presence of uniform vertical rotation. Upper bounds for the complex growth rate of an arbitrary oscillatory perturbation of growing amplitude are derived which are important especially when at least one of the boundaries is rigid so that exact solutions in closed form are not obtainable. Further, it is proved that the results obtained herein are uniformly valid for any combination of dynamically free and rigid boundaries. It is also shown that the existing results of rotatory hydrodynamic Rayleigh Benard …

Identity‐Based Schemes For A Secured Big Data And Cloud Ict Framework In Smart Grid System, Feng Ye, Yi Qian, Rose Qingyang Hu

Electrical and Computer Engineering Faculty Publications

Smart grid is an intelligent cyber physical system (CPS). The CPS generates a massive amount of data for efficient grid operation. In this paper, a big data‐driven, cloud‐based information and communication technology (ICT) framework for smart grid CPS is proposed. The proposed ICT framework deploys hybrid cloud servers to enhance scalability and reliability of smart grid communication infrastructure. Because the data in the ICT framework contains much privacy of customers and important data for automated controlling, the security of data transmission must be ensured. In order to secure the communications over the Internet in the system, identity‐based schemes are proposed …