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Articles 1 - 30 of 43
Full-Text Articles in Physics
Coordination Chemistry Of Uranyl Ions With Surface-Immobilized Peptides: An Xps Study, Esha Mishra, Cody M. Schultz, Rebecca Lai, Peter A. Dowben
Coordination Chemistry Of Uranyl Ions With Surface-Immobilized Peptides: An Xps Study, Esha Mishra, Cody M. Schultz, Rebecca Lai, Peter A. Dowben
Department of Physics and Astronomy: Faculty Publications
The coordination chemistry of uranyl ions with surface immobilized peptides was studied using X-ray photoemission spectroscopy (XPS). All the peptides in the study were modified using a six-carbon alkanethiol as a linker on a gold substrate with methylene blue as the redox label. The X-ray photoemission spectra reveal that each modified peptide interacts differently with the uranyl ion. For all the modified peptides, the XPS spectra were taken in both the absence and presence of the uranium, and their comparison reveals that the interaction depends on the chemical group present in the peptides. The XPS results show that, among all …
Ultrafast Electron Diffraction: Visualizing Dynamic States Of Matter, D. Filippetto, P. Musumeci, R. K. Li, B. J. Siwick, M. R. Otto, Martin Centurion, J. P. F. Nunes
Ultrafast Electron Diffraction: Visualizing Dynamic States Of Matter, D. Filippetto, P. Musumeci, R. K. Li, B. J. Siwick, M. R. Otto, Martin Centurion, J. P. F. Nunes
Department of Physics and Astronomy: Faculty Publications
Since the discovery of electron-wave duality, electron scattering instrumentation has developed into a powerful array of techniques for revealing the atomic structure of matter. Beyond detecting local lattice variations in equilibrium structures with the highest possible spatial resolution, recent research efforts have been directed toward the long-sought-after dream of visualizing the dynamic evolution of matter in real time. The atomic behavior at ultrafast timescales carries critical information on phase transition and chemical reaction dynamics, the coupling of electronic and nuclear degrees of freedom in materials and molecules, and the correlation among structure, function, and previously hidden metastable or nonequilibrium states …
Search For New Particles In An Extended Higgs Sector With Four Bquarks In The Final State At √S=13tev, Cms Collaboration
Search For New Particles In An Extended Higgs Sector With Four Bquarks In The Final State At √S=13tev, Cms Collaboration
Department of Physics and Astronomy: Faculty Publications
A search for a massive resonance X decaying to a pair of spin-0 bosons φ that themselves decay to pairs of bottom quarks, is presented. The analysis is restricted to the mass ranges mφ from 25 to 100GeVand mX from 1 to 3TeV. For these mass ranges, the decay products of each φ boson are expected to merge into a single large-radius jet. Jet substructure and flavor identification techniques are used to identify these jets. The search is based on CERN LHC proton-proton collision data at √s=13 TeV, collected with the CMS detector in 2016–2018, corresponding to an …
Surface Versus Bulk State Transitions In Inkjet-Printed All-Inorganic Perovskite Quantum Dot Films, Thilini K. Ekanayaka, Dylan Richmond, Mason Mccormick, Shashank R. Nandyala, Halle C. Helfrich, Alexander Sinitskii, Jon M. Pikal, Carolina C. Ilie, Peter A. Dowben, Andrew J. Yost
Surface Versus Bulk State Transitions In Inkjet-Printed All-Inorganic Perovskite Quantum Dot Films, Thilini K. Ekanayaka, Dylan Richmond, Mason Mccormick, Shashank R. Nandyala, Halle C. Helfrich, Alexander Sinitskii, Jon M. Pikal, Carolina C. Ilie, Peter A. Dowben, Andrew J. Yost
Department of Physics and Astronomy: Faculty Publications
The anion exchange of the halides, Br and I, is demonstrated through the direct mixing of two pure perovskite quantum dot solutions, CsPbBr3 and CsPbI3, and is shown to be both facile and result in a completely alloyed single phase mixed halide perovskite. Anion exchange is also observed in an interlayer printing method utilizing the pure, unalloyed perovskite solutions and a commercial inkjet printer. The halide exchange was confirmed by optical absorption spectroscopy, photoluminescent spectroscopy, X-ray diffraction, and X-ray photoemission spectroscopy characterization and indicates that alloying is thermodynamically favorable, while the formation of a clustered alloy is …
Injection Of Electron Beams Into Two Laser Wakefields And Generation Of Electron Rings, Q. Chen, Dominika Maslarova, J. Wang, S. Li, Donald Umstadter
Injection Of Electron Beams Into Two Laser Wakefields And Generation Of Electron Rings, Q. Chen, Dominika Maslarova, J. Wang, S. Li, Donald Umstadter
Department of Physics and Astronomy: Faculty Publications
Mutual injection of electron beams into two laser plasma wakefields was observed experimentally when driving laser pulses interfered in plasma at a small crossing angle and were slightly relatively delayed, approximately by one pulse duration. Particle-in-cell simulations revealed that the mutual injection was sensitive to the spatial overlap of the laser pulses, which therefore could be used to control the mutual injection. The dual synchronized, femtosecond electron beams are potentially useful for pump-probe experiments in ultrafast science. In addition, out-of-axis ring-shaped electron beams were detected in both experiments and simulations.
Domain Wall Enabled Steep Slope Switching In Mos2 Transistors Towards Hysteresis-Free Operation, Jingfeng Song, Yubo Qi, Zhiyong Xiao, Kun Wang, Dawei Li, Seung-Hyun Kim, Angus I. Kingon, Andrew M. Rappe, Xia Hong
Domain Wall Enabled Steep Slope Switching In Mos2 Transistors Towards Hysteresis-Free Operation, Jingfeng Song, Yubo Qi, Zhiyong Xiao, Kun Wang, Dawei Li, Seung-Hyun Kim, Angus I. Kingon, Andrew M. Rappe, Xia Hong
Department of Physics and Astronomy: Faculty Publications
The device concept of ferroelectric-based negative capacitance (NC) transistors offers a promising route for achieving energyefficient logic applications that can outperform the conventional semiconductor technology, while viable operation mechanisms remain a central topic of debate. In this work, we report steep slope switching in MoS2 transistors back-gated by single-layer polycrystalline PbZr0.35Ti0.65O3. The devices exhibit current switching ratios up to 8 × 106 within an ultra-low gate voltage window of Vg = ±0:5 V and subthreshold swing (SS) as low as 9.7 mV decade−1 at room temperature, transcending the 60 mV decade …
Topological Phase Transitions And Berry-Phase Hysteresis In Exchange-Coupled Nanomagnets, Ahsan Ullah, Xin Li, Yunlong Jin, Rabindra Pahari, Lanping Yue, Xiaoshan S. Xu, Balamurugan Balasubramanian,, David J. Sellmyer, Ralph Skomski
Topological Phase Transitions And Berry-Phase Hysteresis In Exchange-Coupled Nanomagnets, Ahsan Ullah, Xin Li, Yunlong Jin, Rabindra Pahari, Lanping Yue, Xiaoshan S. Xu, Balamurugan Balasubramanian,, David J. Sellmyer, Ralph Skomski
Department of Physics and Astronomy: Faculty Publications
Topological phase in magnetic materials yields a quantized contribution to the Hall effect known as the topological Hall effect, which is often caused by skyrmions, with each skyrmion creating a magnetic flux quantum ±h/e. The control and understanding of topological properties in nanostructured materials is the subject of immense interest for both fundamental science and technological applications, especially in spintronics. In this work, the electron-transport properties and spin structure of exchange-coupled cobalt nanoparticles with an average particle size of 13.7 nm are studied experimentally and theoretically. Magnetic and Hall-effect measurements identify topological phase transitions in the exchange-coupled cobalt …
Ultrafast Electron Diffraction From Transiently Aligned Asymmetric Top Molecules: Rotational Dynamics And Structure Retrieval, Kyle Wilkin, Yanwei Xiong, Haoran Zhao, Sri Bhavya Muvva, S. K. Saha, Martin Centurion
Ultrafast Electron Diffraction From Transiently Aligned Asymmetric Top Molecules: Rotational Dynamics And Structure Retrieval, Kyle Wilkin, Yanwei Xiong, Haoran Zhao, Sri Bhavya Muvva, S. K. Saha, Martin Centurion
Department of Physics and Astronomy: Faculty Publications
Ultrafast electron diffraction (UED) from aligned molecules in the gas phase has successfully retrieved structures of both linear and symmetric top molecules. Alignment of asymmetric tops has been recorded with UED but no structural information was retrieved. We present here the extraction of two-dimensional structural information from simple transformations of experimental diffraction patterns of aligned molecules as a proof-of-principle for the recovery of the full structure. We align 4-fluorobenzotrifluoride with a linearly polarized laser and show that we can distinguish between atomic pairs with equal distances that are parallel and perpendicular to the aligned axis. We additionally show with numerical …
Measurements Of The Associated Production Of A W Boson And A Charm Quark In Proton–Proton Collisions At √S = 8tev, A. Tumasyan
Measurements Of The Associated Production Of A W Boson And A Charm Quark In Proton–Proton Collisions At √S = 8tev, A. Tumasyan
Department of Physics and Astronomy: Faculty Publications
Measurements of the associated production of a W boson and a charm (c) quark in proton–proton collisions at a centre-of-mass energy of 8 TeV are reported. The analysis uses a data sample corresponding to a total integrated luminosity of 19.7 fb−1 collected by the CMS detector at the LHC. The W bosons are identified through their leptonic decays to an electron or a muon, and a neutrino. Charm quark jets are selected using distinctive signatures of charm hadron decays. The product of the cross section and branching fraction σ(pp → W + c + X)β(W → ℓν), where ℓ …
Measurements Of The Higgs Boson Production Cross Section And Couplings In The W Boson Pair Decay Channel In Proton-Proton Collisions At √S = 13tev, A. Tumasyan
Department of Physics and Astronomy: Faculty Publications
Production cross sections of the standard model Higgs boson decaying to a pair of W bosons are measured in proton-proton collisions at a center-of-mass energy of 13 TeV. The analysis targets Higgs bosons produced via gluon fusion, vector boson fusion, and in association with a W or Z boson. Candidate events are required to have at least two charged leptons and moderate missing transverse momentum, targeting events with at least one leptonically decaying W boson originating from the Higgs boson. Results are presented in the form of inclusive and differential cross sections in the simplified template cross section framework, as …
Measurement Of The Mass Dependence Of The Transverse Momentum Of Lepton Pairs In Drell–Yan Production In Proton–Proton Collisions At √S = 13tev, A. Tumasyan
Department of Physics and Astronomy: Faculty Publications
The double differential cross sections of the Drell–Yan lepton pair (ℓ + ℓ −, dielectron or dimuon) production are measured as functions of the invariant mass mℓℓ, transverse momentum pT(ℓℓ), and ϕ∗η. The ϕ∗η observable, derived from angular measurements of the leptons and highly correlated with pT(ℓℓ), is used to probe the low-pT(ℓℓ) region in a complementary way. Dilepton masses up to 1 TeV are investigated. Additionally, a measurement is performed requiring at least one jet in the final state. To benefit from partial cancellation …
Spontaneous Polarization In An Ultrathin Improper-Ferroelectric/Dielectric Bilayer In A Capacitor Structure At Cryogenic Temperatures, Yu Yun, Pratyush Buragohain, Arashdeep Singh Thind, Yuewei Yin, Xin Li, Xuanyuan Jiang, Rohan Mishra, Alexei Gruverman, X. S. Xu
Spontaneous Polarization In An Ultrathin Improper-Ferroelectric/Dielectric Bilayer In A Capacitor Structure At Cryogenic Temperatures, Yu Yun, Pratyush Buragohain, Arashdeep Singh Thind, Yuewei Yin, Xin Li, Xuanyuan Jiang, Rohan Mishra, Alexei Gruverman, X. S. Xu
Department of Physics and Astronomy: Faculty Publications
To determine the effect of depolarization and the critical thickness in improper-ferroelectric hexagonal-ferrite thin films, we investigate the polarization switching of a ferroelectric/dielectric bilayer in capacitor structures at 20 K. Experimentally, we show that the spontaneous polarization persists throughout the studied thickness range (3 to 80 unit cell), even with a thick (10-nm) dielectric layer, suggesting no practical thickness limit for applications. By fitting the effect of depolarization using the phenomenological theory, we show that the spontaneous polarization remains finite when the thickness of the ferroelectric layer approaches zero, providing a hint for the absence of critical thickness. We also …
Retrieval Of The Molecular Orientation Distribution From Atom-Pair Angular Distributions, Yanwei Xiong, Kyle J. Wilkin, S. K. Saha, Sri Bhavya Muvva, Haoran Zhao, Martin Centurion
Retrieval Of The Molecular Orientation Distribution From Atom-Pair Angular Distributions, Yanwei Xiong, Kyle J. Wilkin, S. K. Saha, Sri Bhavya Muvva, Haoran Zhao, Martin Centurion
Department of Physics and Astronomy: Faculty Publications
Imaging laser-induced rotational dynamics is an important and active field due to its applications in capturing reactions in the molecular frame and in molecular imaging. Experimental measurement of the molecular orientation distribution, as a function of the Euler angles, has been demonstrated for special cases when the detectable signal is generated along the molecular symmetry axis. Here we developed the general theory that maps the probability density distribution of the molecular orientation to the atom-pair angular distributions for nonlinear molecules. With the theory, the molecular orientation distribution can be retrieved from the measured atom-pair angular distribution, which we demonstrate experimentally …
Positronium Collisions With Polar Molecules, R. S. Wilde, M. K. Selvage, Ilya I. Fabrikant
Positronium Collisions With Polar Molecules, R. S. Wilde, M. K. Selvage, Ilya I. Fabrikant
Department of Physics and Astronomy: Faculty Publications
We calculate elastic and positronium (Ps) break-up cross sections for collisions of Ps with the polar molecules CO, HCl, and LiF in the fixed-nuclei approximation. We incorporate electron exchange and correlation for these processes by using the free-electron-gas model developed earlier for Ps scattering by rare-gas atoms, N2, O2, and CO2 molecules. The present target molecules provide a range of dipole moments from the weakly polar CO to the strongly polar LiF. We find that Ps scattering is similar to electron scattering when the cross sections are plotted as a function of projectile velocity for …
Search For A W' Boson Decaying To A Vector-Like Quark And A Top Or Bottom Quark In The All-Jets Final State At √S = 13 Tev, The Cms Collaboration
Search For A W' Boson Decaying To A Vector-Like Quark And A Top Or Bottom Quark In The All-Jets Final State At √S = 13 Tev, The Cms Collaboration
Department of Physics and Astronomy: Faculty Publications
A search is presented for a heavy W0 boson resonance decaying to a B or T vector-like quark and a t or a b quark, respectively. The analysis is performed using protonproton collisions collected with the CMS detector at the LHC. The data correspond to an integrated luminosity of 138 fb−1 at a center-of-mass energy of 13TeV. Both decay channels result in a signature with a t quark, a Higgs or Z boson, and a b quark, each produced with a significant Lorentz boost. The all-hadronic decays of the Higgs or Z boson and of the t quark are …
Leptogenesis Triggered By A First-Order Phase Transition, Peisi Huang, Ke-Pan Xie
Leptogenesis Triggered By A First-Order Phase Transition, Peisi Huang, Ke-Pan Xie
Department of Physics and Astronomy: Faculty Publications
We propose a new scenario of leptogenesis, which is triggered by a first-order phase transition (FOPT). The right-handed neutrinos (RHNs) are massless in the old vacuum, while they acquire a mass in the new vacuum bubbles, and the mass gap is huge compared with the FOPT temperature. The ultra-relativistic bubble walls sweep the RHNs into the bubbles, where the RHNs experience fast decay and generate the lepton asymmetry, which is further converted to the baryon asymmetry of the Universe (BAU). Since the RHNs are out of equilibrium inside the bubble, the generated BAU does not suffer from the thermal bath …
Polarization Topology At The Nominally Charged Domain Walls In Uniaxial Ferroelectrics, Yurii Tikhonov, Jesi R. Maguire, Conor J. Mccluskey, James P. V. Mcconville, Amit Kumar, Haidong Lu, Dennis Meier, Anna Razumnaya, John Martin Gregg, Alexei Gruverman, Valerii M. Vinokur, Igor Luk’Yanchuk
Polarization Topology At The Nominally Charged Domain Walls In Uniaxial Ferroelectrics, Yurii Tikhonov, Jesi R. Maguire, Conor J. Mccluskey, James P. V. Mcconville, Amit Kumar, Haidong Lu, Dennis Meier, Anna Razumnaya, John Martin Gregg, Alexei Gruverman, Valerii M. Vinokur, Igor Luk’Yanchuk
Department of Physics and Astronomy: Faculty Publications
Ferroelectric domain walls provide a fertile environment for novel materials physics. If a polarization discontinuity arises, it can drive a redistribution of electronic carriers and changes in band structure, which often result in emergent 2D conductivity. If such a discontinuity is not tolerated, then its amelioration usually involves the formation of complex topological patterns, such as flux-closure domains, dipolar vortices, skyrmions, merons, or Hopfions. The degrees of freedom required for the development of such patterns, in which dipolar rotation is a hallmark, are readily found in multiaxial ferroelectrics. In uniaxial ferroelectrics, where only two opposite polar orientations are possible, it …
Polarization Angle Dependence Of Vertically Propagating Radio-Frequency Signals In South Polar Ice, Davez Bensson, Ilya Kravchenko, Krishna Nivedita
Polarization Angle Dependence Of Vertically Propagating Radio-Frequency Signals In South Polar Ice, Davez Bensson, Ilya Kravchenko, Krishna Nivedita
Department of Physics and Astronomy: Faculty Publications
To better understand the effect of ice properties on the science reach of radio experiments designed to measure ultrahigh energy neutrinos (UHEN), we recently considered the timing and amplitude characteristics of radio-frequency (RF) signals propagating along multi-kilometer, primarily horizontal trajectories through cold Polar ice at the South Pole. That analysis indicated satisfactory agreement with a model of ice birefringence based on ice crystal (ĉ-axis) data culled from the South Pole Ice Core Experiment (SPICE). Here we explore the geometrically complementary case of signals propagating along primarily vertical trajectories, using extant data from the Askaryan Radio Array (ARA) experiment, …
Physical Vapor Transport Growth Of Antiferromagnetic Crcl3 Flakes Down To Monolayer Thickness, Jia Wang, Zahra Ahmadi, David Lujan, Jeongheon Choe, Xiaoqin Li, Jeffrey E. Shield, Xia Hong
Physical Vapor Transport Growth Of Antiferromagnetic Crcl3 Flakes Down To Monolayer Thickness, Jia Wang, Zahra Ahmadi, David Lujan, Jeongheon Choe, Xiaoqin Li, Jeffrey E. Shield, Xia Hong
Department of Physics and Astronomy: Faculty Publications
The van der Waals magnets CrX3 (X = I, Br, and Cl) exhibit highly tunable magnetic properties and are promising candidates for developing novel two-dimensional (2D) magnetic devices such as magnetic tunnel junctions and spin tunneling transistors. Previous studies of CrCl3 have mainly focused on mechanically exfoliated samples. Controlled synthesis of high quality atomically thin flakes is critical for their technological implementation but has not been achieved to date. Here, we report the growth of large CrCl3 flakes with well-defined facets down to monolayer thickness (~0.6 nm) via the physical vapor transport technique. Long stripes of tri-layer samples …
Efficient Perpendicular Magnetization Switching By A Magnetic Spin Hall Effect In A Noncollinear Antiferromagnet, Shuai Hu, Ding-Fu Shao, Huanglin Yang, Chang Pan, Zhenxiao Fu, Meng Tang, Yumeng Yang, Weijia Fan, Shiming Zhou, Evgeny Y. Tsymbal, Xuepeng Qiu
Efficient Perpendicular Magnetization Switching By A Magnetic Spin Hall Effect In A Noncollinear Antiferromagnet, Shuai Hu, Ding-Fu Shao, Huanglin Yang, Chang Pan, Zhenxiao Fu, Meng Tang, Yumeng Yang, Weijia Fan, Shiming Zhou, Evgeny Y. Tsymbal, Xuepeng Qiu
Department of Physics and Astronomy: Faculty Publications
Current induced spin-orbit torques driven by the conventional spin Hall effect are widely used to manipulate the magnetization. This approach, however, is nondeterministic and inefficient for the switching of magnets with perpendicular magnetic anisotropy that are demanded by the high-density magnetic storage and memory devices. Here, we demonstrate that this limitation can be overcome by exploiting a magnetic spin Hall effect in noncollinear antiferromagnets, such as Mn3Sn. The magnetic group symmetry of Mn3Sn allows generation of the out-of-plane spin current carrying spin polarization collinear to its direction induced by an in-plane charge current. This spin current drives an …
Majorana Bound States With Chiral Magnetic Textures, Utkan Güngördü, Alexey Kovalev
Majorana Bound States With Chiral Magnetic Textures, Utkan Güngördü, Alexey Kovalev
Department of Physics and Astronomy: Faculty Publications
The aim of this Tutorial is to give a pedagogical introduction into realizations of Majorana fermions, usually termed as Majorana bound states (MBSs), in condensed matter systems with magnetic textures. We begin by considering the Kitaev chain model of “spinless” fermions and show how two “half” fermions can appear at chain ends due to interactions. By considering this model and its two-dimensional generalization, we emphasize intricate relation between topological superconductivity and possible realizations of MBS. We further discuss how “spinless” fermions can be realized in more physical systems, e.g., by employing the spin-momentum locking. Next, we demonstrate how magnetic textures …
Spin-Neutral Tunneling Anomalous Hall Effect, Ding-Fu Shao, Shu-Hui Zhang, Rui-Chun Xiao, Zi-An Wang, W. J. Lu, Y. P. Sun, Evgeny Y. Tsymbal
Spin-Neutral Tunneling Anomalous Hall Effect, Ding-Fu Shao, Shu-Hui Zhang, Rui-Chun Xiao, Zi-An Wang, W. J. Lu, Y. P. Sun, Evgeny Y. Tsymbal
Department of Physics and Astronomy: Faculty Publications
Anomalous Hall effect (AHE) is a fundamental spin-dependent transport property that is widely used in spintronics. It is generally expected that currents carrying net spin polarization are required to drive the AHE. Here we demonstrate that, in contrast to this common expectation, a spin-neutral tunneling AHE (TAHE), i.e. a TAHE driven by spin-neutral currents, can be realized in an antiferromagnetic (AFM) tunnel junction where an AFM electrode with a non-spin-degenerate Fermi surface and a normal metal electrode are separated by a non-magnetic barrier with strong spin-orbit coupling (SOC). The symmetry mismatch between the AFM electrode and the SOC barrier results …
Search For Flavor-Changing Neutral Current Interactions Of The Top Quark And Higgs Boson In Final States With Two Photons In Proton-Proton Collisions At √S =13 Tev, A. Tumasyan
Department of Physics and Astronomy: Faculty Publications
Proton-proton interactions resulting in final states with two photons are studied in a search for the signature of flavor-changing neutral current interactions of top quarks (t) and Higgs bosons (H). The analysis is based on data collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb−1. No significant excess above the background prediction is observed. Upper limits on the branching fractions (Ɓ) of the top quark decaying to a Higgs boson and an up (u) or charm …
Explosive Spontaneous Emulsification, Xuefei Wu, Gautam Bordia, Robert Streubel, Jaffar Hasnain, Ahmad K. Omar, Phillip L. Geissler, Dong Wang, Han Xue, Jianjun Wang, Thomas P. Russell
Explosive Spontaneous Emulsification, Xuefei Wu, Gautam Bordia, Robert Streubel, Jaffar Hasnain, Ahmad K. Omar, Phillip L. Geissler, Dong Wang, Han Xue, Jianjun Wang, Thomas P. Russell
Department of Physics and Astronomy: Faculty Publications
Spontaneous emulsification, resulting from the assembly and accumulation of surfactants at liquid-liquid interfaces, is an interfacial instability where microdroplets are generated and diffusively spread from the interface until complete emulsification. Here, we show that an external magnetic field can modulate the assembly of paramagnetic nanoparticle surfactants (NPSs) at liquid-liquid interfaces and trigger an oversaturation in the areal density of the NPSs at the interface, as evidenced by the reduction in the interfacial tension, γ, and corroborated with a magnetostatic continuum theory. Despite the significant reduction in γ, the presence of the magnetic field does not cause stable interfaces to become …
Probing Charm Quark Dynamics Via Multiparticle Correlations In Pb-Pb Collisions At √SNn =5.02 Tev, A. Tumasyan
Probing Charm Quark Dynamics Via Multiparticle Correlations In Pb-Pb Collisions At √SNn =5.02 Tev, A. Tumasyan
Department of Physics and Astronomy: Faculty Publications
Multiparticle azimuthal correlations of prompt D0 mesons are measured in Pb-Pb collisions at a nucleon-nucleon center-of-mass energy of √sNN = 5.02 TeV. For the first time, a four-particle cumulant method is used to extract the second Fourier coefficient of the azimuthal distribution (ν2) of D0 mesons as a function of event centrality and the D0 transverse momentum. The ratios of the four-particle v2 values to previously measured two-particle cumulant results provide direct experimental access to event-by-event fluctuations of charm quark azimuthal anisotropies. These ratios are also found to be comparable to …
First Search For Exclusive Diphoton Production At High Mass With Tagged Protons In Proton-Proton Collisions At √S =13 Tev, A. Tumasyan
Department of Physics and Astronomy: Faculty Publications
A search for exclusive two-photon production via photon exchange in proton-proton collisions, pp → pγγp with intact protons, is presented. The data correspond to an integrated luminosity of 9.4 fb−1 collected in 2016 using the CMS and TOTEM detectors at a center-of-mass energy of 13 TeVat the LHC. Events are selected with a diphoton invariant mass above 350 GeVand with both protons intact in the final state, to reduce backgrounds from strong interactions. The events of interest are those where the invariant mass and rapidity calculated from the momentum losses of the forward-moving protons match the mass and rapidity …
Time-Varying Resonant Mass At Collider And Beam Dump Experiments, Jinhui Guo, Yuxuan He, Jia Liu, Xiao-Ping Wang, Ke-Pan Xie
Time-Varying Resonant Mass At Collider And Beam Dump Experiments, Jinhui Guo, Yuxuan He, Jia Liu, Xiao-Ping Wang, Ke-Pan Xie
Department of Physics and Astronomy: Faculty Publications
A new particle usually manifests itself as a single resonant peak located at its mass. We propose if the new particle mass is time-varying due to environmental effects, then its mass spectrum typically has a novel double-peak feature. A representative model is the kinetic mixing dark photon interacting with an ultralight complex scalar dark matter charged under U(1)'. We reanalyze the existing experiments, showing the constraints on such a model are drastically weakened than those on the traditional single-peak resonance model, due to the reduction of the luminosity exposure in each resonant mass bin. Consequently, for mass around tens …
Induced Spin Textures At 3D Transition Metal–Topological Insulator Interfaces, Slimane Laref, Sumit Ghosh, Evgeny Y. Tsymbal, Aurelien Manchon
Induced Spin Textures At 3D Transition Metal–Topological Insulator Interfaces, Slimane Laref, Sumit Ghosh, Evgeny Y. Tsymbal, Aurelien Manchon
Department of Physics and Astronomy: Faculty Publications
While some of the most elegant applications of topological insulators, such as the quantum anomalous Hall effect, require the preservation of Dirac surface states in the presence of time-reversal symmetry breaking, other phenomena such as spin-charge conversion rather rely on the ability for these surface states to imprint their spin texture on adjacent magnetic layers. In this Rapid Communication, we investigate the spin-momentum locking of the surface states of a wide range of monolayer transition metals (3d-TM) deposited on top of Bi2Se3 topological insulators using first-principles calculations. We find an anticorrelation between the magnetic moment …
Superfluid Spin Transistor, Edward Schwartz, Bo Li, Alexey Kovalev
Superfluid Spin Transistor, Edward Schwartz, Bo Li, Alexey Kovalev
Department of Physics and Astronomy: Faculty Publications
We propose to use the Hall response of topological defects, such as merons and antimerons, to spin currents in two-dimensional magnetic insulator with in-plane anisotropy for identification of the Berezinskii-Kosterlitz-Thouless (BKT) transition in a transistorlike geometry. Our numerical results relying on a combination of Monte Carlo and spin dynamics simulations show transition from spin superfluidity to conventional spin transport, accompanied by the universal jump of the spin stiffness and exponential growth of the transverse vorticity current. We propose a superfluid spin transistor in which the spin and vorticity currents are modulated by changes in density of free topological defects, e.g., …
First-Order Phase Transition And Fate Of False Vacuum Remnants, Kiyoharu Kawana, Philip Lu, Ke-Pan Xie
First-Order Phase Transition And Fate Of False Vacuum Remnants, Kiyoharu Kawana, Philip Lu, Ke-Pan Xie
Department of Physics and Astronomy: Faculty Publications
False vacuum remnants in first-order phase transitions in the early Universe can form compact objects which may constitute dark matter. Such remnants form because particles develop large mass gaps between the two phases and become trapped in the old phase. We focus on remnants generated in a class of models with trapped dark sector particles, trace their development, and determine their ultimate fate. Depending on model and phase transition parameters, the evolutionary endpoint of these remnants can be primordial black holes, Fermi-balls, Q-balls, or thermal balls, and they all have the potential to constitute some portion or the whole of …