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Full-Text Articles in Physics
Exploring The Coronal Magnetic Field With Galactic Cosmic Rays: The Sun Shadow Observed By Hawc, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, R. Babu, Et Al.
Exploring The Coronal Magnetic Field With Galactic Cosmic Rays: The Sun Shadow Observed By Hawc, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, R. Babu, Et Al.
Michigan Tech Publications, Part 2
Galactic cosmic rays (GCRs) are charged particles that reach the heliosphere almost isotropically in a wide energy range. In the inner heliosphere, the GCR flux is modulated by solar activity so that only energetic GCRs reach the lower layers of the solar atmosphere. In this work, we propose that high-energy GCRs can be used to explore the solar magnetic fields at low coronal altitudes. We used GCR data collected by the High-Altitude Water Cherenkov observatory to construct maps of GCR flux coming from the Sun’s sky direction and studied the observed GCR deficit, known as Sun shadow (SS), over a …
A Jwst Survey Of The Supernova Remnant Cassiopeia A, Dan Milisavljevic, Tea Temim, Ilse De Looze, Danielle Dickinson, J. Martin Laming, Robert Fesen, John C. Raymond, Richard G. Arendt, Jacco Vink, Bettina Posselt, George G. Pavlov, Ori D. Fox, Ethan Pinarski, Bhagya Subrayan, Judy Schmidt, William P. Blair, Armin Rest, Daniel Patnaude, Bon Chul Koo, Jeonghee Rho, Salvatore Orlando, Hans Thomas Janka, Moira Andrews, Michael J. Barlow, Adam Burrows, Roger Chevalier, Geoffrey Clayton, Claes Fransson, Christopher Fryer, Haley L. Gomez, Florian Kirchschlager
A Jwst Survey Of The Supernova Remnant Cassiopeia A, Dan Milisavljevic, Tea Temim, Ilse De Looze, Danielle Dickinson, J. Martin Laming, Robert Fesen, John C. Raymond, Richard G. Arendt, Jacco Vink, Bettina Posselt, George G. Pavlov, Ori D. Fox, Ethan Pinarski, Bhagya Subrayan, Judy Schmidt, William P. Blair, Armin Rest, Daniel Patnaude, Bon Chul Koo, Jeonghee Rho, Salvatore Orlando, Hans Thomas Janka, Moira Andrews, Michael J. Barlow, Adam Burrows, Roger Chevalier, Geoffrey Clayton, Claes Fransson, Christopher Fryer, Haley L. Gomez, Florian Kirchschlager
Michigan Tech Publications, Part 2
We present initial results from a James Webb Space Telescope (JWST) survey of the youngest Galactic core-collapse supernova remnant, Cassiopeia A (Cas A), made up of NIRCam and MIRI imaging mosaics that map emission from the main shell, interior, and surrounding circumstellar/interstellar material (CSM/ISM). We also present four exploratory positions of MIRI Medium Resolution Spectrograph integral field unit spectroscopy that sample ejecta, CSM, and associated dust from representative shocked and unshocked regions. Surprising discoveries include (1) a weblike network of unshocked ejecta filaments resolved to ∼0.01 pc scales exhibiting an overall morphology consistent with turbulent mixing of cool, low-entropy matter …
Machine Learning Techniques For Intermediate Mass Gap Lepton Partner Searches At The Large Hadron Collider, Bhaskar Dutta, Tathagata Ghosh, Alyssa Horne, Jason Kumar, Sean Palmer, Pearl Sandick, Marcus Snedeker, Patrick Stengel, Joel W. Walker
Machine Learning Techniques For Intermediate Mass Gap Lepton Partner Searches At The Large Hadron Collider, Bhaskar Dutta, Tathagata Ghosh, Alyssa Horne, Jason Kumar, Sean Palmer, Pearl Sandick, Marcus Snedeker, Patrick Stengel, Joel W. Walker
Michigan Tech Publications, Part 2
We consider machine learning techniques associated with the application of a boosted decision tree (BDT) to searches at the Large Hadron Collider (LHC) for pair-produced lepton partners which decay to leptons and invisible particles. This scenario can arise in the minimal supersymmetric Standard Model (MSSM), but can be realized in many other extensions of the Standard Model (SM). We focus on the case of intermediate mass splitting (∼30 GeV) between the dark matter (DM) and the scalar. For these mass splittings, the LHC has made little improvement over LEP due to large electroweak backgrounds. We find that the use of …
Constraints On Metastable Superheavy Dark Matter Coupled To Sterile Neutrinos With The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, K. Nguyen, D. Nitz, Et Al.
Constraints On Metastable Superheavy Dark Matter Coupled To Sterile Neutrinos With The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, K. Nguyen, D. Nitz, Et Al.
Michigan Tech Publications, Part 2
Dark matter particles could be superheavy, provided their lifetime is much longer than the age of the Universe. Using the sensitivity of the Pierre Auger Observatory to ultrahigh energy neutrinos and photons, we constrain a specific extension of the Standard Model of particle physics that meets the lifetime requirement for a superheavy particle by coupling it to a sector of ultralight sterile neutrinos. Our results show that, for a typical dark coupling constant of 0.1, the mixing angle θm between active and sterile neutrinos must satisfy, roughly, θm≲1.5×10-6(MX/109 GeV)-2 for a mass MX of the dark-matter particle between 108 GeV …
Estimating Polarization Purity With Noise, Alex Kostinski, Dan Kestner, Jothiram Vivekanandan
Estimating Polarization Purity With Noise, Alex Kostinski, Dan Kestner, Jothiram Vivekanandan
Michigan Tech Publications, Part 2
We formulate a problem of estimating and monitoring mismatch (unwanted departure from orthogonality) of two ostensibly orthogonal polarization channels in a fully polarimetric general device such as a polarimetric weather radar. A statistical approach is proposed by using thermal noise or, more generally, a 'polarimetric noise' class of sources. The suitable noise class of distributions is shown to be rooted in the complex multivariate Gaussian probability density function (pdf), the latter possessing a uniform pdf on the Poincare sphere (PS), with a probability measure given by a fractional surface area. To that end, we develop a parameter to estimate polarization …
Light Curve And Hardness Tests For Millilensing In Grb 081122a, Grb 081126a, Grb 110517b, And Grb 210812a, Oindabi Mukherjee, Robert J. Nemiroff
Light Curve And Hardness Tests For Millilensing In Grb 081122a, Grb 081126a, Grb 110517b, And Grb 210812a, Oindabi Mukherjee, Robert J. Nemiroff
Michigan Tech Publications, Part 2
Analyses are given on four recent gravitational millilensing claims on gamma-ray bursts (GRBs): GRB 081122A, GRB 081126A, GRB 110517B, and GRB 210812A. Two tests, a light curve similarity test and a hardness similarity test, compare different temporal sections of a single GRB to see if they are statistically similar. The hardness similarity test shows that the ratio between the second and the first emission episodes in each energy channel differed from the same ratio averaged over all energy channels at above 90 per cent confidence level in GRB 081122A. Additionally, the light curve similarity test applied to GRB 081122A, GRB …
First-Principles Study Of Hydrogen Storage Application Of Ti3c2tx Monolayer Mxene, Yi Zhi Chu, Kah Chun Lau
First-Principles Study Of Hydrogen Storage Application Of Ti3c2tx Monolayer Mxene, Yi Zhi Chu, Kah Chun Lau
Michigan Tech Publications, Part 2
MXene, with its high aspect ratio and adjustable surface properties, has garnered significant attention in the realm of hydrogen storage research. For the first time, considering a ternary/quaternary mixed terminated MXene surface, the authors have investigated comprehensively the hydrogen storage potential of two-dimensional (2D) titanium carbide Ti3C2Tx monolayer MXene using density functional theory (DFT). By considering mixed terminated surfaces, this study indicated the locally induced dipole due to the mixed termination is beneficial in facilitating hydrogen adsorption with stronger average adsorption energies than that of the uniform F-/O-/OH-/H-terminated surfaces. The authors estimated a compelling average H2 surface adsorption energy on …
Progress In Electronic, Energy, Biomedical And Environmental Applications Of Boron Nitride And Mos2 Nanostructures, Join Uddin, Raksha Dubey, Vinaayak Sivam Balasubramaniam, Jeff Kabel, Vedika Khare, Zohreh Salimi, Sambhawana Sharma, Dongyan Zhang, Yoke Khin Yap
Progress In Electronic, Energy, Biomedical And Environmental Applications Of Boron Nitride And Mos2 Nanostructures, Join Uddin, Raksha Dubey, Vinaayak Sivam Balasubramaniam, Jeff Kabel, Vedika Khare, Zohreh Salimi, Sambhawana Sharma, Dongyan Zhang, Yoke Khin Yap
Michigan Tech Publications, Part 2
In this review, we examine recent progress using boron nitride (BN) and molybdenum disulfide (MoS) nanostructures for electronic, energy, biomedical, and environmental applications. The scope of coverage includes zero-, one-, and two-dimensional nanostructures such as BN nanosheets, BN nanotubes, BN quantum dots, MoS nanosheets, and MoS quantum dots. These materials have sizable bandgaps, differentiating them from other metallic nanostructures or small-bandgap materials. We observed two interesting trends: (1) an increase in applications that use heterogeneous materials by combining BN and MoS nanostructures with other nanomaterials, and (2) strong research interest in environmental applications. Last, we encourage researchers to study how …
Detection Of Small Drizzle Droplets In A Large Cloud Chamber Using Ultrahigh-Resolution Radar, Zeen Zhu, Fan Yang, Pavlos Kollias, Raymond A. Shaw, Alexander Kostinski, Steve Krueger, Katia Lamer, Nithin Allwayin, Mariko Oue
Detection Of Small Drizzle Droplets In A Large Cloud Chamber Using Ultrahigh-Resolution Radar, Zeen Zhu, Fan Yang, Pavlos Kollias, Raymond A. Shaw, Alexander Kostinski, Steve Krueger, Katia Lamer, Nithin Allwayin, Mariko Oue
Michigan Tech Publications, Part 2
A large convection-cloud chamber has the potential to produce drizzle-sized droplets, thus offering a new opportunity to investigate aerosol-cloud-drizzle interactions at a fundamental level under controlled environmental conditions. One key measurement requirement is the development of methods to detect the low-concentration drizzle drops in such a large cloud chamber. In particular, remote sensing methods may overcome some limitations of in situ methods. Here, the potential of an ultrahigh-resolution radar to detect the radar return signal of a small drizzle droplet against the cloud droplet background signal is investigated. It is found that using a small sampling volume is critical to …
First-Principles Study Of Mxene Properties With Varying Hydrofluoric Acid Concentration, Yi Zhi Chu, Megan Hoover, Patrick Ward, Kah Chun Lau
First-Principles Study Of Mxene Properties With Varying Hydrofluoric Acid Concentration, Yi Zhi Chu, Megan Hoover, Patrick Ward, Kah Chun Lau
Michigan Tech Publications, Part 2
With varying hydrofluoric acid (HF) concentrations under three etching conditions, we presented a comparative study of the effects of both the ordered and randomly ternary mixed terminated Ti3C2Tx surfaces with a wide variation of O/OH/F stoichiometry on the thermodynamic stability and electronic properties. Regardless of the HF concentration, an OH-rich surface is found to be thermodynamically stable and the electrical conductivity of Ti3C2Tx is substantially affected by the OH concentration. The charge density difference and electron localization function demonstrated a significant electron localization at the hydroxyl group on the O/OH/F mixed terminated surface, which could yield a locally induced dipole …
Search For Decaying Dark Matter In The Virgo Cluster Of Galaxies With Hawc, A. Albert, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, H. A. Ayala Solares, R. Babu, R. Turner, X. Wang, Et Al.
Search For Decaying Dark Matter In The Virgo Cluster Of Galaxies With Hawc, A. Albert, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, H. A. Ayala Solares, R. Babu, R. Turner, X. Wang, Et Al.
Michigan Tech Publications, Part 2
The decay or annihilation of dark matter particles may produce a steady flux of very-high-energy gamma rays detectable above the diffuse background. Nearby clusters of galaxies provide excellent targets to search for the signatures of particle dark matter interactions. In particular, the Virgo cluster spans several degrees across the sky and can be efficiently probed with a wide field-of-view instrument. The High Altitude Water Cherenkov (HAWC) observatory, due to its wide field of view and sensitivity to gamma rays at an energy scale of 300 GeV-100 TeV is well-suited for this search. Using 2141 days of data, we search for …
Resolving The Topology Of Encircling Multiple Exceptional Points, Chitres Guria, Qi Zhong, Sahin Kaya Ozdemir, Yogesh S.S. Patil, Ramy El-Ganainy, Jack Gwynne Emmet Harris
Resolving The Topology Of Encircling Multiple Exceptional Points, Chitres Guria, Qi Zhong, Sahin Kaya Ozdemir, Yogesh S.S. Patil, Ramy El-Ganainy, Jack Gwynne Emmet Harris
Michigan Tech Publications, Part 2
Non-Hermiticity has emerged as a new paradigm for controlling coupled-mode systems in ways that cannot be achieved with conventional techniques. One aspect of this control that has received considerable attention recently is the encircling of exceptional points (EPs). To date, most work has focused on systems consisting of two modes that are tuned by two control parameters and have isolated EPs. While these systems exhibit exotic features related to EP encircling, it has been shown that richer behavior occurs in systems with more than two modes. Such systems can be tuned by more than two control parameters, and contain EPs …
Galactic Gamma-Ray Diffuse Emission At Tev Energies With Hawc Data, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, R. Babu, Et Al.
Galactic Gamma-Ray Diffuse Emission At Tev Energies With Hawc Data, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, R. Babu, Et Al.
Michigan Tech Publications, Part 2
Galactic gamma-ray diffuse emission (GDE) is emitted by cosmic rays (CRs), ultra-relativistic protons, and electrons, interacting with gas and electromagnetic radiation fields in the interstellar medium. Here we present the analysis of teraelectronvolt diffuse emission from a region of the Galactic plane over the range in longitude of l ∈ [43°, 73°], using data collected with the High Altitude Water Cherenkov (HAWC) detector. Spectral, longitudinal, and latitudinal distributions of the teraelectronvolt diffuse emission are shown. The radiation spectrum is compatible with the spectrum of the emission arising from a CR population with an index similar to that of the observed …
Demonstrating Agreement Between Radio And Fluorescence Measurements Of The Depth Of Maximum Of Extensive Air Showers At The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, D. Nitz, K. Nguyen, A. Puyleart, Et Al.
Demonstrating Agreement Between Radio And Fluorescence Measurements Of The Depth Of Maximum Of Extensive Air Showers At The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, D. Nitz, K. Nguyen, A. Puyleart, Et Al.
Michigan Tech Publications, Part 2
We show, for the first time, radio measurements of the depth of shower maximum (Xmax) of air showers induced by cosmic rays that are compared to measurements of the established fluorescence method at the same location. Using measurements at the Pierre Auger Observatory we show full compatibility between our radio and the previously published fluorescence dataset, and between a subset of air showers observed simultaneously with both radio and fluorescence techniques, a measurement setup unique to the Pierre Auger Observatory. Furthermore, we show radio Xmax resolution as a function of energy and demonstrate the ability to make competitive high-resolution Xmax …
Radio Measurements Of The Depth Of Air-Shower Maximum At The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, D. Nitz, K. Nguyen, A. Puyleart, Et Al.
Radio Measurements Of The Depth Of Air-Shower Maximum At The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, D. Nitz, K. Nguyen, A. Puyleart, Et Al.
Michigan Tech Publications, Part 2
The Auger Engineering Radio Array (AERA), part of the Pierre Auger Observatory, is currently the largest array of radio antenna stations deployed for the detection of cosmic rays, spanning an area of 17 km2 with 153 radio stations. It detects the radio emission of extensive air showers produced by cosmic rays in the 30-80 MHz band. Here, we report the AERA measurements of the depth of the shower maximum (Xmax), a probe for mass composition, at cosmic-ray energies between 1017.5 and 1018.8 eV, which show agreement with earlier measurements with the fluorescence technique at the Pierre Auger Observatory. We show …
Designing A Convection-Cloud Chamber For Collision-Coalescence Using Large-Eddy Simulation With Bin Microphysics, Aaron Wang, Mikhail Ovchinnikov, Fan Yang, Silvio Schmalfuss, Raymond A. Shaw
Designing A Convection-Cloud Chamber For Collision-Coalescence Using Large-Eddy Simulation With Bin Microphysics, Aaron Wang, Mikhail Ovchinnikov, Fan Yang, Silvio Schmalfuss, Raymond A. Shaw
Michigan Tech Publications, Part 2
Collisional growth of cloud droplets is an essential yet uncertain process for drizzle and precipitation formation. To improve the quantitative understanding of this key component of cloud-aerosol-turbulence interactions, observational studies of collision-coalescence in a controlled laboratory environment are needed. In an existing convection-cloud chamber (the Pi Chamber), collisional growth is limited by low liquid water content and short droplet residence times. In this work, we use numerical simulations to explore various configurations of a convection-cloud chamber that may intensify collision-coalescence. We employ a large-eddy simulation (LES) model with a size-resolved (bin) cloud microphysics scheme to explore how cloud properties and …
Light Curve And Hardness Tests For Millilensing In Grb 950830, Grb 090717a, And Grb 200716c, Oindabi Mukherjee, Robert J. Nemiroff
Light Curve And Hardness Tests For Millilensing In Grb 950830, Grb 090717a, And Grb 200716c, Oindabi Mukherjee, Robert J. Nemiroff
Michigan Tech Publications, Part 2
Two different temporal sections of a single gamma-ray burst (GRB) must be statistically similar to show an internal gravitational lensing signature. Here, two straightforward gravitational lensing tests are defined and applied: a light curve similarity test and a hardness similarity test. Gravitational millilensing has been claimed to be detected within several individual GRBs that contain two emission episodes separated by a time-delay. However, our analyses indicate that none of those claims satisfy both tests. The hardness similarity test performed on GRB 950830 and GRB 090717A found that the ratio between the second and the first emission episodes in each energy …
Constraining Models For The Origin Of Ultra-High-Energy Cosmic Rays With A Novel Combined Analysis Of Arrival Directions, Spectrum, And Composition Data Measured At The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, D. Nitz, A. Puyleart, Et Al.
Constraining Models For The Origin Of Ultra-High-Energy Cosmic Rays With A Novel Combined Analysis Of Arrival Directions, Spectrum, And Composition Data Measured At The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, D. Nitz, A. Puyleart, Et Al.
Michigan Tech Publications, Part 2
The combined fit of the measured energy spectrum and shower maximum depth distributions of ultra-high-energy cosmic rays is known to constrain the parameters of astrophysical models with homogeneous source distributions. Studies of the distribution of the cosmic-ray arrival directions show a better agreement with models in which a fraction of the flux is non-isotropic and associated with the nearby radio galaxy Centaurus A or with catalogs such as that of starburst galaxies. Here, we present a novel combination of both analyses by a simultaneous fit of arrival directions, energy spectrum, and composition data measured at the Pierre Auger Observatory. The …