Digital Commons Network^™

Study Of The Ic 443 Region With The Hawc Observatory, R. Alfaro, C. Alvarez, M. Araya, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, Et. Al

Michigan Tech Publications

Supernova remnants are one potential source class considered a PeVatron (i.e., capable of accelerating cosmic rays above PeV energies). The shock fronts produced after the explosion of the supernova are ideal regions for particle acceleration. IC 443 is a supernova remnant that has been studied extensively at different wavelengths. Using 2966 days of gamma-ray data from the High Altitude Water Cherenkov (HAWC) observatory, we study the emission of IC 443 with the objective of finding signatures of cosmic-ray acceleration at the PeV scale. Using a maximum likelihood method, we find a point source located at (α=94.°42, δ=22.°35) that we associate …

Construction, Optimization, And Characterization Of An Undergraduate Cold Cathode Table-Top Electron Accelerator For Radiation Physics Education, Caitlin Balmer, Mason Skeath, Mehran M. Zaini, Peter Zencak, Erin M. Craig

Journal of the Symposium of University Research and Creative Expression

Project Mentor(s): Mehran Zaini, PhD; Peter Zencak

Rising cancer cases spurred advancements in radiation therapy modalities, including electron accelerators. In this report, descriptive and diagnostic analysis was utilized to develop and characterize a functional, low energy cold cathode table-top electron accelerator for radiation physics experimentation in Central Washington University’s (CWU) undergraduate radiation lab. The device features a tungsten cathode (TC), brass anode, and copper Faraday Cup (FC) in a vacuum, enclosed by blue-tinted polyvinyl chloride (PVC). TC electron emission was facilitated by applied electric fields from input voltages of 1000 V to 5000 V. FC collected electron current in the …

Synthesis Of Nitrogen-Enriched 3d Graphene Foam For Electrochemical Sensing Of Hydrogen Peroxide (H₂O₂), Bhargavi Dronavalli, Madhava Rao Vallabhaneni, Jatla Murali Prakash, Deepti Kolli, Dandamudi Srilaxmi

Karbala International Journal of Modern Science

In this work, A simple hydrothermal process was utilized to create 3D-foam-type Nitrogen-doped graphene (NDG). The synthesized material was characterized using a range of physicochemical characterization techniques. These techniques confirm that nitrogen is successfully incorporated into the carbon network, resulting in NDG. Cyclic voltammetry (CV) investigation demonstrated that NDG-modified glassy carbon electrode (NDG/GCE) displayed finite charge transfer properties against typical redox systems. NDG/GCE is identified as a simple, facile, and efficient electrocatalyst material for the estimation of hydrogen peroxide (H₂O₂). From CV analysis, it is revealed that NDG/GCE can produce a signal for electrochemical quantification of …

Plasmonic Nanoparticle Integration On Fiber Optic: Role Of Organic Linker And Functionalization Length In Refractive Index Sensing, Shela Ilmiyah, Mohamad Syahadi, Muflikhah Muflikhah, Yuwana Pradana, Zainul Arifin Iman Supardi, Iwan Darmadi, Lia Aprilia

Makara Journal of Science

Nanoplasmonic fiber optic sensors leverage the optical fiber’s inherent compactness and surface sensitivity via evanescent-field interactions with the localized surface plasmon resonance of the metallic nanoparticles. One of the popular approaches is self-assembly owing to its relatively low cost. Despite its low cost, the self-assembly technique has low reproducibility and exhibits low sensitivity because of low nanoplasmonic coverage on the fiber optic surface. In this study, several fabrication techniques were explored to assess the refractive index sensitivity by comparing three common organosilanes, i.e., (3-Aminopropyl)triethoxysilane (APTES), (3-Aminopropyl)trimethoxysilane, and (3-Mercaptopropyl)trimethoxysilane. Comparative analyses assessed the anchoring efficiency of the three silanes, sensor reproducibility, …

Hawc, Veritas, Fermi-Lat, And Xmm-Newton Follow-Up Observations Of The Unidentified Ultra-High-Energy Gamma-Ray Source Lhaaso J2108+5157, C. B. Adams, P. Bangale, W. Benbow, J. H. Buckley, Y. Chen, J. L. Christiansen, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, X. Wang, Et. Al

Michigan Tech Publications

We report observations of the ultra-high-energy gamma-ray source LHAASO J2108+5157, utilizing VERITAS, HAWC, Fermi-LAT, and XMM-Newton. VERITAS has collected ∼40 hr of data that we used to set ULs to the emission above 200 GeV. The HAWC data, collected over ∼2400 days, reveal emission between 3 and 146 TeV, with a significance of 7.5σ, favoring an extended source model. The best-fit spectrum measured by HAWC is characterized by a simple power law with a spectral index of 2.45 ± 0.11stat. Fermi-LAT analysis finds a point source with a very soft spectrum in the LHAASO J2108+5157 region, consistent with the 4FGL-DR3 …

Synthesis And Characterization Of Fe-Zn Bimetallic Nanoparticles Via Two-Step Laser Ablation And Their Antibacterial Activity, Hudhaifa M. Mohammed, Sahar Naji Rashid

Karbala International Journal of Modern Science

In this study, Nd: YAG laser at a wavelength of (1064 nm), energies of (300 and 400 mJ), and a pulse repetition rate of (3 Hz) was used to synthesize metallic nanoparticles from iron and zinc individually using a one-step pulsed laser ablation approach, followed by the two-step synthesis of bimetallic nanoparticles. The physical properties of the synthesized nanoparticles were then investigated using UV-visible (UV-Vis), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and energy-dispersive X-ray (EDX) techniques. The results of characterization of the obtained NPs confirmed the formation of core-shell nanocomposites, as evidenced by the increased absorbance intensity of …

Modeling-Based Prediction Of Current Oscillation With The Josephson Frequency In Voltage-Biased Phase-Slip Center Filaments, Armen Gulian

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this article, we demonstrate that the voltage-biased phase-slip center (PSC) can act as a direct equivalent (not merely an analogy) of the Josephson effect in Josephson junctions (JJs). We analyze the behavior of PSCs in the case when a constant voltage V is applied to the superconducting filament. The analysis is performed using finite element modeling on the basis of time-dependent Ginzburg–Landau (TDGL) equations. It reveals that the current in the filament oscillates with the Josephson frequency ω = 2eV/h. This fact may have important corollaries in practice.

Solutions For Linear Fractional Differential Equations With Multiple Constraints Using Fractional B-Poly Bases, Md. Habibur Rahman, Muhammad I. Bhatti, Nicholas Dimakis

Physics & Astronomy Faculty Publications

This study presents an innovative numerical method for solving linear fractional differential equations (LFDEs) using modified Bernstein polynomial bases. The proposed approach effectively addresses the challenges posed by the nonlocal nature of fractional derivatives, providing a robust framework for handling multiple initial and boundary value constraints. By integrating the LFDEs and approximating the solutions with modified fractional-order Bernstein polynomials, we derive operational matrices to solve the resulting system numerically. The method’s accuracy is validated through several examples, showing excellent agreement between numerical and exact solutions. Comparative analysis with existing data further confirms the reliability of the approach, with absolute errors …

Effect Of Varying Chitosan Molecular Weights On The Morphology And Physical Characteristics Of Pva/Chitosan Composite Hydrogels, Yuan Alfinsyah Sihombing, Halida Rahmi Luthfianti, William Xaveriano Waresindo, Marathur Rodhiyah, Nur’Aini Nafisah, Dian Ahmad Hapidin, Dhewa Edikresnha, Khairurrijal Khairurrijal

Makara Journal of Science

We employed the innovative freeze–thaw method to investigate the effect of chitosan (CS) molecular weights incorporated into polyvinyl alcohol on the morphology and physical characteristics of the hydrogel. This study aimed to unravel the intricate relationships between CS molecular weight variations, CS concentration, and the number of freeze–thaw cycles (4 or 6 cycles) on hydrogel swelling degree and weight loss. Incorporating CS improved the hydrogel structure and enhanced its porosity, resulting in remarkable increases in swelling degree ranging from 2 to 6 times the initial weight. Higher molecular weight CS (310,000–375,000 Da) exhibited a lower swelling degree than medium molecular …

Enhancing Science Learning Outcomes With Sitaya Miniature Media: A Quantitative Study Of Elementary Education, Gilang Kripsiyadi Praramdana, Hamdan Hamdan, Agus Gunawan, Fauziah Dwi Hijriani

Jurnal Pendidikan Sains

This study investigates the impact of SITAYA Miniature media on the learning outcomes of grade VI students in science subjects at SDN 2 Darma. Conventional teaching methods, often less engaging for students, were identified as a significant factor contributing to low academic performance. The study employed a quantitative research approach, with a randomized sample of 43 students divided into an experimental group (24 students) and a control group (19 students). Pretest and posttest data were collected using a structured test instrument, and statistical analyses, including normality, homogeneity, t-tests, and N-Gain tests, were conducted to assess the effectiveness of SITAYA Miniature …

Beta Particles Impact On The Optical Properties Of Tio₂ Thin Films, Farah S. Dakhil, Hassan M.Jaber Al-Ta’Ii

Al-Bahir

TiO₂ is a semiconductor with a wide band gap and is utilized in various applications, including photovoltaics, solar cells, and photocatalysis. In this work, TiO₂ thin films were fabricated using the doctor blade technique and deposited onto glass substrates. The purpose of the study was to investigate how beta irradiation affected the optical properties of the TiO₂ films. The produced samples' absorbance and photon energy were the main subjects of the measurements. While the samples exposed to beta rays for 30, 60, and 90 minutes had direct band gaps of 3.87 eV, 3.75 eV, and 3.66 eV, …

Eng- Semicon: Understanding Nanoscale Heat Transport In Wide- And Ultrawide Bandgap Semiconductors Using Novel Deep Ultraviolet Tools, Joshua Lee Knobloch

Funded Research Records

No abstract provided.

Click-Ready Gold Nanoparticles From Aqueous Mechanochemistry: 2-Propynylamine As A Reducing Agent And Surface Ligand, Amber L. Garcia, Brian S. Mitchell, Amanda Reusch, Mark J. Fink, Juan P. Hinestroza, Yelin Ko, Julie P. Vanegas

Physics & Astronomy Faculty Publications

We report a rapid aqueous method for synthesizing monodisperse gold nanoparticles (AuNPs), employing 2-propynylamine as both an intrinsic reducing agent and a surface-stabilizing ligand. This self-mediated process—achieved in a single step—yields spherical AuNPs with an average diameter of 4.0 ± 1.0 nm and a well-defined localized surface plasmon resonance band centered at 520 nm. Acting as a bifunctional molecule, 2-propynylamine simultaneously reduces HAuCl4·3H2O to elemental gold and passivates the nanoparticle surface through coordination via the amine group, while preserving a terminal alkyne (–C≡CH) functionality. This reactive moiety remains exposed and chemically accessible, enabling post-synthetic modification through Cu(I)-catalyzed azide–alkyne cycloaddition. Control …

Correlation Of Radon Gas Concentrations And Associated Radiological Risks In Soil Using Ssntds With Gis And Spss At Najaf Governorate, Iraq, Rafal Mohamed Abdulsada, Lubna A. Alasadi

Al-Bahir

All human beings are affected by soil directly or indirectly. This study focuses on the effect of radon gas and related radiological risks using SSNTDs, specifically CR-39 detectors, in eighty secondary schools in Najaf and Kufa cities, Najaf Governorate, Iraq. As we recognize the importance of soil and its strong connection to humans, the study focused on areas where public and private schools were built, where students are present, and the potential for radiation risks to affect students' health. The results show that the average concentrations of C, C_Rn were 64.329±59.149 Bq / m³ and 3150.699±2897.036 Bq / …

Green Synthesis Of Copper And Silver Nanostructured Particles From Eremurus Plant Extract And Comparison Of Their Optical Properties And Antibacterial Activities, Doaa Ayad Kamil, Ali F. Al-Rawaf, Mohammed Yarub Hani, H.H. Obeed, Tabarek Falah Deindee, Mohammed Ridha Shaeed

Karbala International Journal of Modern Science

In the present investigation, silver (Ag) and copper (Cu) nanostructured particles were synthesized from Eremurus plant by means of an environmentally benign methodology in which plant extracts served as both reducing and stabilizing agents. The resultant nanostructured particles were subjected to characterization techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDXS). XRD analysis confirmed development of Ag nanostructured particles with face-centered cubic (fcc) structure and also Cu nanostructured particles with cubic form. Moreover, the average crystallite dimensions obtained for Ag and Cu were 18.3 nm and 65.7 nm, …

Fabrication And Characterization Of Epoxy Resin Co-Doped With 2,5-Diphenyloxazole And Cerium Fluoride Nanoparticles For Radiation Detection, Akapong Phunpueok, Jaruwan Seangrit, Sarawut Jaiyen, Krittiya Sreebunpeng, Wuttichai Chaiphaksa, Kewalee Nilgumhang, Voranuch Thongpool

Karbala International Journal of Modern Science

This paper presents the fabrication and characterization of a plastic scintillator prepared from epoxy resin doped with 2,5-diphenyloxazole (PPO) and cerium fluoride nanoparticles (CeF₃ NPs) for radiation detection. The CeF₃ NPs were prepared by a chemical process and examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM); it was found that the prepared particles were true CeF₃ NPs with an average particle size of approximately 17 nm. The CeF₃ NPs were co-doped with PPO into epoxy resin and formed into a plastic scintillator of 3 cm in diameter and 2 cm in length. Analysis of …

Hybrid Path Planner For Centralized Multi-Robotic Long-Vehicle Based On Adaptive Dimensionality And Grey Wolf Algorithm, Noor Kadhim Ayoob, Ali Hadi Hasan

Karbala International Journal of Modern Science

The present robot planning methods pay no attention to the impact of the robot's size and the space it occupies in the environment on path planning. This paper presents a centralized hybrid method to plan optimal paths for multiple robotic long vehicles (RLVs) competing with each other to reach one common goal, taking into account the space that must be available to the RLV at each step to avoid narrow spaces that are too small to pass through. The environment analysis for each RLV is improved by assigning constant weight to the obstacles and calculating two new parameters: safety (SF) …

Unified Study Of The Classical Hall Effect, Carter J. Reed, Javier E. Hasbun, Wyatt E. Ackerman, L Ajith Desilva

Georgia Journal of Science

Germanium (Ge) samples with different doping types, acceptors (p-type) and donors (n-type), were studied to investigate charge carrier behavior. Carrier concentrations were found to be 1.16×10^21 m^(-3) for the p-type sample and 7.337×10^20 m^(-3) for the n-type sample. These experiments were conducted for the standard Hall effect (Hall voltage versus low magnetic field (B) values) as well as conductivity and Hall voltage versus temperature for different B-fields. The measurements versus temperature at zero-field allow us to obtain band gap ( Eg). While we investigate the conductivities for n-type and p-type doped samples, we also study the conductivity of an undoped …

Unveiling The Interplay Of Electronic And Phononic Excitations In Laser-Induced Oxygen Activation On Ru(0001), Xiangrui Wang, Jiamin Wang, Paul Spiering, Liping Liu, Jörg Meyer, Jerry L. Larue, Hongliang Xin

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Understanding laser-induced dynamics on metal surfaces poses significant challenges due to the intricate interplay between electronic and phononic degrees of freedom, which evolve on distinct timescales. In this study, we introduce a machine learning-accelerated approach to molecular dynamics simulations that incorporates anisotropic electronic friction, providing deeper insights into these complex processes. Our framework extends the accessible time and length scales for nonadiabatic dynamics simulations, enabling a detailed investigation of the laser-induced activation of oxygen on the Ru(0001) surface. Statistical analysis reveals that strong electronic excitation dominates the first 800 fs after laser exposure. Beyond this timescale, energy deposited by electronic …

Influence Of Variable Climate On Mechanical Properties Of Composite Materials: An Experimental Study, Alexandra Tazhibaeva, Safaa M.R.H. Hussein, Mikhail Kuznetsov, Farid Shakirzyanov, Nikita Kharin, Igor Muravyev, Timur Agliullin, Gulshat Saleeva, Victor Mitryakin, Oleg Morozov, Oskar Sachenkov

Karbala International Journal of Modern Science

This study investigates the degradation of carbon fiber-reinforced plastic composites, fabricated via non-autoclave molding, under tropical climatic conditions across three regions over three years. Forty specimens (10 control, 30 exposed) with 2x2 twill weave and 0°/90° fiber orientation were subjected to tensile and compressive testing, microscopy, and X-ray computed tomography. Control specimens established baseline properties, while exposed specimens underwent three-year weathering. Statistical and principal component analyses revealed significant mechanical degradation, with tensile strength decreasing by up to 16.1% (p

Impact Of Plasma-Activated Water On Breast Cancer Cell Viability, Maryam G. Jasim, Hammad R. Humud

Karbala International Journal of Modern Science

Plasma-activated water (PAW) was generated using a dielectric barrier discharge (DBD) plasma system operating with a 1:1 mixture of nitrogen and argon gases to evaluate its cytotoxic effects on MCF-7 breast cancer cells. Water samples were divided into five groups: 0 minutes (control), 5, 10, 15, and 20 minutes of plasma exposure. The resulting PAW was applied to cultured cells, and cell viability was assessed 24- and 48-hour post-treatment. Viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results showed an apparent time-dependent increase in cytotoxicity. At 24 hours, cell mortality rates were 1.9%, 40.7%, 48.1%, 53.6%, …

Engineered Biochar-Attapulgite Clay Composite: A Novel Slow-Release Phosphorus Fertilizer, Harleen Kaur, Gurwinder Singh, Marjana Yeasmin, Kavitha Ramadass, Puspamitra Panigrahi, Alan Larson, Ranjit Pati, Dane Lamb, Bo Zheng, Ehsan Tavakkoli, Lukas Van Zwieten, Ajayan Vinu

Michigan Tech Publications

Sustainable agricultural practices are in high demand, and the development of innovative materials for slow nutrient release holds utmost importance. Phosphorus (P) stratification limits plant P availability in no-till farming systems. To address this, a nano composite-based P fertilizer to release nutrients in the root zone following surface soil application is constructed. The nanocomposite fertilizers (BAP-SRFs) were formed by a combination of different amounts of biochar (BC), attapulgite clay (ATP) and KH2PO4, followed by a high-temperature treatment (500 °C). XANES analysis revealed the enrichment of the surface with carbon (C), oxygen (O) and P-containing functional groups, and the bond formation …

Concentration-Dependent Responses Of C. Reinhardtii To Silver Ions: Hormetic Response In Growth And Reduction Of Motility, Hemanta Pradhan, Arpan Poudel, Diksha Shrestha, Ariel Rogers, Michael Stewart, Amani Jereb, Jack Harper, Ming Li, Wen Zhang, Jingyi Chen, Yong Wang

Physics Faculty Publications and Presentations

Elevated levels of silver in aquatic environments arising from widespread use of silver nitrate and silver nanoparticles in different sectors of industry and medicine pose significant biophysical challenges to aquatic microorganisms. Despite extensive toxicity studies of silver on bacteria and microbial communities, its influence on other aquatic microorganisms, such as microalgae, remains poorly understood. In this study, we investigated the biophysical response of C. reinhardtii microalgae to silver ion exposure in terms of their population growth dynamics, chlorophyll content, and swimming motility. We found that silver ions at different concentrations (from 0.29 to 1.18 mu\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} …

Nonlinear Stage Of Modulational Instability In Repulsive Two-Component Bose-Einstein Condensates, S. Mossman, S. I. Mistakidis, G. C. Katsimiga, A. Romero-Ros, G. Biondini, P. Schmelcher, P. Engels, P. G. Kevrekidis

Physics Faculty Research & Creative Works

Modulational instability (MI) is a fundamental phenomenon in the study of nonlinear dynamics, spanning diverse areas such as shallow water waves, optics, and ultracold atomic gases. In particular, the nonlinear stage of MI has recently been a topic of intense exploration and has been shown to manifest, in many cases, in the generation of dispersive shock waves (DSWs). In this Letter, we experimentally probe the MI dynamics in an immiscible two-component ultracold atomic gas with exclusively repulsive interactions, catalyzed by a hard-wall-like boundary produced by a repulsive optical barrier. We analytically describe the expansion rate of the DSWs in this …

Coupled-Channel Calculations Of Fully Differential Cross Sections For Ionization In 75-Kev P + He Collisions, K. H. Spicer, N. W. Antonio, M. S. Schöffler, Michael Schulz, A. S. Kadyrov

Physics Faculty Research & Creative Works

The fully differential cross section is the most detailed quantity that can be measured or calculated to study ionization in few-body systems. For 75 keV proton collisions with helium, various experimental data are available. However, previous theoretical calculations found significant discrepancies across the entire range of data. In this work the wave-packet convergent close-coupling method is extended to calculating these cross sections for electrons ejected with energies from 1 to 75.4 eV. The approach utilizes a two-center expansion and correlated two-electron helium wave functions to describe the four-body proton-helium system. While there is good agreement with the experiment for electrons …

Efficient Parallel Processing Of Second-Generation Tdi Data For Galactic Binaries In Space-Based Gravitational Wave Missions, Xue-Hao Zhang, Soumya D. Mohanty, S. R. Valluri, Shao-Dong Zhao, Qun-Ying Xie, Yu-Xiao Liu

Physics & Astronomy Faculty Publications

Space-based gravitational wave missions such as LISA, Taiji, and Tianqin rely on the time-delay interferometry (TDI) technique to observe low-frequency signals such as Galactic binaries (GBs), massive black-hole binaries, and extreme-mass-ratio inspirals. Among these sources, resolving the large population of GBs poses a central challenge for data analysis. In this work, we present GBSIEVER-C, a pipeline implemented in C and parallelized using OpenMP (Open Multi-Processing), along with a range of additional algorithmic optimizations, including a fast implementation of second-generation TDI response modeling. It builds upon the previous MATLAB-based pipeline that demonstrated competitive performance on LISA Data Challenge (LDC) data. To …

Modeling The Basal Ganglia Network Using Leaky Integrate-And-Fire Neurons To Explore Its Role In Facilitating Purposive Saccades, Saarth Anjali Chitale

All ETDs from UAB

Saccadic eye movements provide a well-defined behavioral readout for investigating how the basal ganglia (BG) contribute to action selection. While saccades are controlled by multiple brain regions, including direct excitatory inputs from various cortices, the BG exerts a key inhibitory influence. Decades of experimental work using saccadic behavioral paradigms in non-human primates have yielded important insights into the activity of BG populations. These include the caudate nucleus, subthalamic nucleus, globus pallidus externus, and substantia nigra pars reticulata, as well as dopaminergic afferents from the substantia nigra pars compacta and efferent projections to the superior colliculus, which controls eye movements. Despite …

Gw250114: Testing Hawking’S Area Law And The Kerr Nature Of Black Holes, The Ligo Scientific Collaboration, The Virgo Collaboration, The Kagra Collaboration

Department of Physics and Astronomy Faculty Scholarship and Creative Works

The gravitational-wave signal GW250114 was observed by the two LIGO detectors with a network matched-filter signal-to-noise ratio of 80. The signal was emitted by the coalescence of two black holes with near-equal masses 𝑚1=33.6+1.2−0.8⁢𝑀⊙ and 𝑚2=32.2+0.8−1.3⁢𝑀⊙, and small spins 𝜒1,2≤0.26 (90% credibility) and negligible eccentricity 𝑒⁢≤0.03. Postmerger data excluding the peak region are consistent with the dominant quadrupolar (ℓ=|𝑚|=2) mode of a Kerr black hole and its first overtone. We constrain the modes’ frequencies to ±30% of the Kerr spectrum, providing a test of the remnant’s Kerr nature. We also examine Hawking’s area law, also known as the second law …

Gw250114: Testing Hawking’S Area Law And The Kerr Nature Of Black Holes, A. G. Abac, I. Abouelfettouh, F. Acernese, Teviet Creighton, Mario C. Diaz, R. Espinosa, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, M. Ramos Arevalo, Wenhui Wang

Physics & Astronomy Faculty Publications

The gravitational-wave signal GW250114 was observed by the two LIGO detectors with a network matched-filter signal-to-noise ratio of 80. The signal was emitted by the coalescence of two black holes with near-equal masses m_{1}=33.6_{-0.8}^{+1.2}M_{⊙} and m_{2}=32.2_{-1.3}^{+0.8}M_{⊙}, and small spins χ_{1,2}≤0.26 (90% credibility) and negligible eccentricity e≤0.03. Postmerger data excluding the peak region are consistent with the dominant quadrupolar (ℓ=|m|=2) mode of a Kerr black hole and its first overtone. We constrain the modes' frequencies to ±30% of the Kerr spectrum, providing a test of the remnant's Kerr nature. We also examine Hawking's area law, also known as the second law …

Multiply Differential Study Of Detachment With Simultaneous Target Excitation In Anion-Atom Collisions, M. Schulz, F. Herrmann, W. Zhang, D. V. Chicharro, A. Dorn, M. Grieser, F. Grussie, H. Kreckel, O. Novotny, F. Trost, A. Wolf, T. Pfeifer, C. D. Schröter

Physics Faculty Research & Creative Works

We have measured momenta of electrons and recoil ions in triple coincidence with neutralized projectiles for slow collisions between various anions and target atoms. From the data we extracted triple differential momentum and angular distributions of electrons ejected in detachment, in detachment with simultaneous target ionization (DI), and in detachment with simultaneous target excitation (DE). The DI rates relative to the DE rates depend sensitively on the projectile speed and on the properties of the target.