Physics Commons^™

Search For A Higgs Boson Produced In Association With A Z Boson In Pp̅ Collisions, V. M. Abazov, Kenneth A. Bloom, Gregory Snow

Gregory Snow Publications

We describe a search for the Standard Model Higgs boson with a mass of 105 GeV/c² to 145 GeV/c² in data corresponding to an integrated luminosity of approximately 450 pb^-1 collected with the DØ detector at the Fermilab Tevatron p̅p collider at a center-of-mass energy of 1.96 TeV. The Higgs boson is required to be produced in association with a Z boson, and the Z boson is required to decay to either electrons or muons with the Higgs boson decaying to a b̅b pair. The data are well described by the expected background, leading to …

Rapidity And Species Dependence Of Particle Production At Large Transverse Momentum For D+Au Collisions At √ Snn = 200 Gev, B.I. Abelev, J. Adams, M.M. Aggarwal, J. Amonett, B.D. Anderson, M. Anderson, D. Arkhipkin, G.S. Averichev, Y. Bai, J. Balewski, O. Barannikova, L.S. Barnby, J. Baudot, S. Bekele, V.V. Belaga, A. Bellingeri-Laurikainen, R. Bellwied, F. Benedosso, S. Bhardwaj, A. Bhasin, A.K. Bhati, H. Bichsel, J. Bielcik, J. Bielcikova, L.C. Bland, S.L. Blyth, B.E. Bonner, M. Botje, J. Bouchet, A.V. Brandin, A. Bravar, M. Bystersky, R.V. Cadman, X.Z. Cai, H. Caines, M. Calderon De La Barca Sanchez, J. Castillo, O. Catu, D. Cebra, Z. Chajecki, P. Chaloupka, S. Chattopadhyay, H.F. Chen, J.H. Chen, J. Cheng, M. Cherney, A. Chikanian, W. Christie, J.P. Coffin, T.M. Cormier, M.R. Cosentino, J.G. Cramer, H.J. Crawford, D. Das, S. Das, M. Daughertiy, M.M De Moura, T.G. Dedovich, M. Dephillips, A.A. Derevschikov, L. Didenko, T. Dietel, P. Djawotho, S.M Dogra, W.J. Dong, X. Dong, J.E. Draper, F. Du, V.B. Dunin, J.C. Dunlop, M.R. Dutta Mazumdar, V. Eckardt, W.R. Edwards, L.G. Efimov, V. Emelianov, J. Engelage, G. Eppley, B. Erazmus, M. Estienne, P. Fachini, R. Fatemi, J. Fedorisin, K. Filimonov, P. Filip, E. Finch, V. Fine, Y. Fisyak, J. Fu, C.A. Gagliardi, L. Gaillard, M.S. Ganti, V. Ghazikhanian, P. Ghosh, J.E. Gonzalez, Y.G. Gorbunov, H. Gos, O. Grebenyuk, D. Grosnick, S.M. Guertin, K.S.F.F. Guimaraes, Y. Guo, N. Gupta, T.D. Gutierrez, B. Haag, T.J. Hallman, A. Hamed, J.W. Harris, W. He, M. Heinz, T.W. Henry, S. Hepplemann, B. Hippolyte, A. Hirsch, E. Hjort, A.M. Hoffman, G.W. Hoffmann, M.J. Horner, H.Z. Huang, S.L. Huang, E.W. Hughes, T.J. Humanic, G. Igo, P. Jacobs, W.W. Jacobs, P. Jakl, F. Jia, H. Jiang, P.G. Jones, E.G. Judd, S. Kabana, K. Kang, J. Kapitan, M. Kaplan, D. Keane, A. Kechechyan, V.Yu. Khodyrev, B.C. Kim, J. Kiryluk, A. Kisiel, E.M. Kislov, S.R. Klein, A. Kocoloski, D.D. Koetke, T. Kollegger, M. Kopytine, L. Kotchenda, V. Kouchpil, K.L. Kowalik, M. Kramer, P. Kravtsov, V.I. Kravtsov, K. Krueger, C. Kuhn, A.I. Kulikov, A. Kumar, A.A. Kuznetsov, M.A.C. Lamont, J.M. Landgraf, S. Lange, S. Lapointe, F. Laue, J. Lauret, A. Lebedev, R. Lednicky, C.-H. Lee, S. Lehocka, M.J. Levine, C. Li, Q. Li, G. Lin, S.J. Lindenbaum, M.A. Lisa, F. Liu, H. Liu, J. Liu, L. Liu, Z. Liu, T. Ljubicic, W.J. Llope, H. Long, R.S. Longacre, M. Lopez-Noriega, W.A. Love, Y. Lu, T. Ludlam, D. Lynn, G.L. Ma, J.G. Ma, Y.G. Ma, D. Magestro, D.P. Mahapatra, R. Majka, L.K. Mangotra, R. Manweiler, S. Margetis, C. Markert, L. Martin, H.S. Matis, Yu.A. Matulenko, C.J. Mcclain, T.S. Mcshane, Yu. Melnick, A. Meschanin, J. Millane, M.L. Miller, N.G. Minaev, S. Mioduszewski, C. Mironov, A. Mischke, D.K. Mishra, J. Mitchell, B. Mohanty, L. Molnar, C.F. Moore, D.A. Morozov, M.G. Munhoz, B.K. Nandi, C. Nattrass, T.K. Nayak, J.M. Nelson, P.K. Netrakanti, V.A. Nikitin, L.V. Nogach, S.B. Nurushev, G. Odyniec, A. Ogawa, V. Okorokov, M. Oldenburg, D. Olson, M. Pachr, S.K. Pal, Y. Panebratsev, S.Y. Panitkin, A.I. Pavlinov, T. Pawlak, T. Peitzmann, V. Perevoztchikov, C. Perkins, W. Peryt, V.A. Petrov, S.C. Phatak, R. Picha, M. Planinic, J. Pluta, N. Poljak, N. Porile, J. Porter, A.M. Poskanzer, M. Potekhin, E. Potrebenikova, B.V.K.S. Potukuchi, D. Prindle, C. Pruneau, J. Putschke, G. Rakness, R. Raniwala, S. Raniwala, R.L. Ray, S.V. Razin, J. Reinnarth, D. Relyea, F Retiere, A. Ridiger, H.G. Ritter, J.B. Roberts, O.V. Rogachevskiy, J.L. Romero, A. Rose, C. Roy, L. Ruan, M.J. Russcher, R. Sahoo, T. Sakuma, S. Salur, J. Sanweiss, M. Sarsour, P.S. Sazhin, J. Schambach, R.P. Scharenberg, N. Schmitz, K. Schweda, J. Serger, I. Selyuzhenkov, P. Seyboth, A. Shabetai, E. Shahaliev, M. Shao, M. Sharma, W.Q. Shen, S.S. Shimanskiy, E. Sichtermann, F. Simon, R.N. Singaraju, N. Smirnov, R. Snellings, G. Sood, P. Sorensen, J. Sowinski, J. Speltz, H.M. Spinka, B. Srivastava, A. Stadnik, T.D.S. Stanislaus, R. Stock, A. Stolpovsky, M. Strikhanov, B. Stringfellow, A.A.P. Suaide, E. Sugarbaker, M. Sumbera, Z. Sun, B. Surrow, M. Swanger, T.J.M. Symons, A. Szanto De Toledo, A. Tai, J. Takahashi, A.H. Tang, T. Tarnowsky, D. Thein, J.H. Thomas, A.R. Timmins, S. Timoshenko, M. Tokarev, T.A. Trainor, S. Trentalange, R.E. Tribble, O.D. Tsai, J. Ulery, T. Ullrich, D.G. Underwood, G. Van Buren, N. Van Der Kolk, M. Van Leeuwen, A.M. Vander Molen, R. Varma, I.M. Vasilevski, A.N. Vasiliev, R. Vernet, S.E. Vigdor, Y.P. Viyogi, S. Vokal, S.A. Voloshin, W.T. Waggoner, F. Wang, G. Wang, J.S. Wang, X.L. Wang, J.W. Watson, J.C. Webb, G.D. Westfall, A. Wetzler, C. Whitten Jr., H. Wieman, S.W. Wissink, R. Witt, J. Wood, J. Wu, N. Xu, Q.H. Xu, Z. Xu, P. Yepes, I.-K. Yoo, V.I. Yurevich, W. Zhan, H. Zang, W.M. Zhang, Y. Zhang, Z.P. Zhang, Y. Zhao, C. Zong, R. Zoulkarneev, Y. Zoulkarneeva, A.N. Zubarev, J.X. Zuo

Physics

We determine rapidity asymmetry in the production of charged pions, protons, and antiprotons for large transverse momentum (pT) for d+Au collisions at sNN−−−√=200 GeV. The rapidity asymmetry is defined as the ratio of particle yields at backward rapidity (Au beam direction) to those at forward rapidity (d beam direction). The identified hadrons are measured in the rapidity regions |y|

Measurement Of The ΛB0 Lifetime Using Semileptonic Decays, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

We report a measurement of the Λ_b⁰ lifetime using a sample corresponding to 1.3 fb^-1 of data collected by the D0 experiment in 2002–2006 during run II of the Fermilab Tevatron collider. The Λ_b⁰ baryon is reconstructed via the decay Λ_b⁰ → μν̅Λ_c⁺ X. Using 4437 ± 329 signal candidates, we measure the Λ_b⁰ lifetime to be τ(Λ_b⁰) = 1.290_-0.110^+0.119 (stat) _-0.091^+0.087 (syst) ps, which is among the most precise measurements in semileptonic Λ_b⁰ decays. This result is in good …

Measurement Of The ΛB0 Lifetime Using Semileptonic Decays, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration

Kenneth Bloom Publications

We report a measurement of the Λ_b⁰ lifetime using a sample corresponding to 1:3 fb^-1 of data collected by the D0 experiment in 2002–2006 during run II of the Fermilab Tevatron collider. The Λ_b⁰ baryon is reconstructed via the decay Λ_b⁰ → μν&#; Λ _c⁺X. Using 4437 ± 329 signal candidates, we measure the Λ_b⁰ lifetime to be τ(Λ_b⁰) = 1.290_-0.110^+0.119 (stat) _-0.091^+0.087(syst) ps, which is among the most precise measurements in semileptonic Λ_b⁰ decays. This result is in …

Harmonic Holography: A New Holographic Principle, Ye Pu, Martin Centurion, Demetri Psaltis

Martin Centurion Publications

The process of second harmonic generation (SHG) has a unique property of forming a sharp optical contrast between noncentrosymmetric crystalline materials and other types of material, which is a highly valuable asset for contrast microscopy. The coherent signal obtained through SHG also allows for the recording of holograms at high spatial and temporal resolution, enabling whole-field four-dimensional microscopy for highly dynamic microsystems and nanosystems. Here we describe a new holographic principle, harmonic holography (H²), which records holograms between independently generated second harmonic signals and reference. We experimentally demonstrate this technique with digital holographic recording of second harmonic signals …

Agn Reddening And Ultraviolet Extinction Curves From Hubble Space Telescope Spectra, C. Martin Gaskell, A. J. Benkler

C. Martin Gaskell Publications

We present intrinsic extinction curves for 14 AGNs. The AGNs have reddenings, E(B-V), of up to 0.36 mag. The majority (13 out of 14) of the extinction curves are not steep in the UV. Of the seven best determined extinction curves, five have extinction curves that are as flat as the standard Galactic curve in the optical and near UV, but flatter in the far UV, and without the λ2175 feature. One AGN, B3 0754+394, has a steep SMC-like extinction curve, and another, Mrk 304, has an LMC-like extinction curve, including a probable λ2175 bump. The remaining seven, lower-quality, extinction …

Ngc 5548: The Agn Energy Budget Problem And The Geometry Of The Broad-Line Region And Torus, C. Martin Gaskell, Elizabeth S. Klimek, Ludmila S. Nazarova

C. Martin Gaskell Publications

We consider in detail the spectral energy distribution (SED) and multi-wavelength variability of NGC 5548. Comparison with the SEDs of other AGNs implies that the internal reddening of NGC 5548 is E(B-V) = 0.17 mag. The extinction curve is consistent with the mean curve of other AGNs found by Gaskell & Benker, but inconsistent with an SMC-type reddening curve. Because most IR emission originates exterior to the broad-line region (BLR), the SED seen by the inner BLR is different from that seen by the outer BLR and from the earth. The most likely BLR covering factor is ~ 40% and …

Transformations Between 2mass, Sdss And Bvri Photometric Systems: Bridging The Near Infrared And Optical, S. Bilir, S. Ak, S. Karaali, A. Cabrera-Lavers, T. S. Chonis, C. Martin Gaskell

C. Martin Gaskell Publications

We present color transformations for the conversion of the 2MASS photometric system to the Johnson-Cousins UBV RI system and further into the SDSS ugriz system. We have taken SDSS gri magnitudes of stars measured with the 2.5-m telescope from SDSS Data Release 5 (DR5), and BV RI and JHK_s magnitudes from Stetson’s catalogue and Cutri et al. (2003), respectively. We matched thousands of stars in the three photometric systems by their coordinates and obtained a homogeneous sample of 825 stars by the following constraints, which are not used in previous transformations: 1) the data are de-reddened, 2) giants are …

Reversal Of Spin Polarization In Fe/Gaas (001) Driven By Resonant Surface States: First-Principles Calculations, Athanasios N. Chantis, Kirill D. Belashchenko, D. L. Smith, Evgeny Y. Tsymbal, Mark Van Schilfgaarde, R. C. Albers

Evgeny Tsymbal Publications

A minority-spin resonant state at the Fe/GaAs(001) interface is predicted to reverse the spin polarization with the voltage bias of electrons transmitted across this interface. Using a Green's function approach within the local spin-density approximation, we calculate the spin-dependent current in a Fe/GaAs/Cu tunnel junction as a function of the applied bias voltage. We find a change in sign of the spin polarization of tunneling electrons with bias voltage due to the interface minority-spin resonance. This result explains recent experimental data on spin injection in Fe/GaAs contacts and on tunneling magnetoresistance in Fe/GaAs/Fe magnetic tunnel junctions.

Half Metallic Ferromagnets, Peter A. Dowben

Peter Dowben Publications

Since its introduction by de Groot and colleagues in the early 1980s [1], the concept of half metallic ferromagnetism has attracted great interest. Idealized, half-metals have only one spin channel for conduction: the spin-polarized band structure exhibits metallic behavior for one spin channel, while the other spin band structure exhibits a gap at the Fermi level. Due to the gap for one spin direction, the density of states at the Fermi level has, theoretically, 100 % spin polarization. This gap in the density of states in one spin at the Fermi level, for example ↓ so N↓(E_{F …}

The Case For Optically Thick High-Velocity Broad-Line Region Gas In Active Galactic Nuclei, Stephanie A. Snedden, C. Martin Gaskell

C. Martin Gaskell Publications

A combined analysis of the profiles of the main broad quasar emission lines in both Hubble Space Telescope and optical spectra shows that while the profiles of the strong UV lines are quite similar, there is frequently a strong increase in the Lyα/Hα ratio in the high-velocity gas.We show that the suggestion that the high-velocity gas is optically thin presents many problems.We show that the relative strengths of the high-velocity wings arise naturally in an optically thick BLR component. An optically thick model successfully explains the equivalent widths of the lines, the Lyα/Hα ratios and flatter Balmer decrements in the …

Discovery Of Polarization Reverberation In Ngc 4151, C. Martin Gaskell, René W. Goosmann, Nelly I. Merkulova, Nikolay M. Shakhovskoy, Masatoshi Shoji

C. Martin Gaskell Publications

Observations of the optical polarization of NGC 4151 in 1997–2003 show variations of an order of magnitude in the polarized flux while the polarization position angle remains constant. The amplitude of variability of the polarized flux is comparable to the amplitude of variability of the total U-band flux, except that the polarized flux follows the total flux with a lag of 8±3 days. The time lag and the constancy of the position angle strongly favor a scattering origin for the variable polarization rather than a non-thermal synchrotron origin. The orientation of the position angle of the polarized flux (parallel to …

Optimization Of Electrostatic Interactions In Protein-Protein Complexes, Kelly Brock, Kemper Talley, Kacey Coley, Petras Kundrotas, Emil Alexov

Publications

In this article, we present a statistical analysis of the electrostatic properties of 298 protein-protein complexes and 356 domain-domain structures extracted from the previously developed database of protein complexes (ProtCom, http://www.ces.clemson.edu/compbio/protcom). For each structure in the dataset we calculated the total electrostatic energy of the binding and its two components, Coulombic and reaction field energy. It was found that in a vast majority of the cases (>90%), the total electrostatic component of the binding energy was unfavorable. At the same time, the Coulombic component of the binding energy was found to favor the complex formation while …

Matched Filtering And Parameter Estimation Of Ringdown Waveforms, Emanuele Berti, Jaime Cardoso, Vitor Cardoso, Marco Cavaglia

Physics Faculty Research & Creative Works

Using recent results from numerical relativity simulations of nonspinning binary black hole mergers, we revisit the problem of detecting ringdown waveforms and of estimating the source parameters, considering both LISA and Earth-based interferometers. We find that Advanced LIGO and EGO could detect intermediate-mass black holes of mass up to ∼10³M_⊙ out to a luminosity distance of a few Gpc. For typical multipolar energy distributions, we show that the single-mode ringdown templates presently used for ringdown searches in the LIGO data stream can produce a significant event loss ( > 10% for all detectors in a large interval of …

Coincidence Angular Correlation In Electron Impact Single Or Double Ionisation Of Atoms And Molecules, E. M. Staicu-Casagrande, Adnan Naja, Xueguang Ren, Mohammed Nekkab, Fabrice Catoire, F. Mezdari, Azzeddine Lahmam-Bennani, Don H. Madison, Ochbadrakh Chuluunbaatar, Boghos B. Joulakian

Physics Faculty Research & Creative Works

Experimental results obtained with our multi-parameter multi-coincidence spectrometer are presented for the (e,3e) double ionisation of Ar and (e,2e) single ionisation of small molecules. The (e,3e) measurements are discussed in terms of competition between the two double ionisation processes present under the chosen kinematics, and qualitative conclusions are given. The results for the ionisation of H₂ and the outer orbital of N₂ are compared with the predictions of the most elaborate available theoretical models for description of the molecular ionisation process. Overall reasonable agreement is observed and tentative interpretations for the discrepancies are discussed.

Two-Center Interference In P-H2 Electron-Transfer Collisions, Daniel Fischer, M. Gudmundsson, Kristian Stochkel, Zoltan Berenyi, Henrik Cederquist, Nicole Haag, Henrik A B Johansson, Sergey B. Levin, Peter Reinhed, Reinhold S. Schuch, Henning T. Schmidt

Physics Faculty Research & Creative Works

We report on measurements of transfer excitation in collisions of 0.3-1.3 MeV protons with spatially oriented H₂ molecules. Evidences of two center interference are found in the angular distribution of the molecule after a transfer excitation process and directly in the projectile angular scattering distributions. These features can be explained in a way which is analogous to that for the interferences in Young's classical double slit experiment: The fast projectiles preferentially capture electrons close to either of the molecular nuclei, and thereby they change their momenta and de Broglie wavelengths. The waves emerging from the two 'slits' of the …

Zeeman Splitting And G Factor Of The 1s²2s²2p ²P3/2 And ²P1/2 Levels In Ar¹³⁺, R. Soria Orts, Jose R. Crespo Lopez-Urrutia, Hjalmar Bruhns, Antonio J. Gonzalez, Zoltan Harman, Ulrich D. Jentschura, Christoph H. Keitel, Alain Lapierre, Hiroyuki Tawara, I. I. Tupitsyn, Joachim Hermann Ullrich, Andrey V. Volotka

Physics Faculty Research & Creative Works

The Zeeman line components of the magnetic-dipole (M1) 1s² 2s^{2 2} P_1/2 -²P_3/2 transition in boronlike Ar¹³⁺ were experimentally resolved by high-precision emission spectroscopy using the Heidelberg electron beam ion trap. We determined the gyromagnetic (g) factors of the ground and first-excited levels to be g_1/2 =0.663(7) and g_3/2 =1.333(2), respectively. This corresponds to a measurement of the g factor of a relativistic electron in a bound non- S state of a multielectron ion with a 1.5 parts-per-thousand accuracy. The results are compared to theoretical calculations by means of the configuration …

Search For BS0→ Μ+ Μ- Decays At D0, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

We report results from a search for the decay B_s⁰ → μ⁺μ^- using 1.3 fb^-1 of pp̅ collisions at √s= 1.96 TeV collected by the D0 experiment at the Fermilab Tevatron Collider.We find two candidate events, consistent with the expected background of 1.24 ± 0.99, and set an upper limit on the branching fraction of Ɓ(B_s⁰ → μ⁺μ^-) < 1.2 x 10^-7 at the 95% C.L.

Bias Voltage Dependence Of Tunneling Anisotropic Magnetoresistance In Magnetic Tunnel Junctions With Mgo And Al2O3 Tunnel Barriers, Li Gao, Xin Jiang, See-Hun Yang, John D. Burton, Evgeny Y. Tsymbal, Stuart S. P. Parkin

Evgeny Tsymbal Publications

Tunneling anisotropic magnetoresistance (TAMR) is observed in tunnel junctions with transition metal electrodes as the moments are rotated from in-plane to out-of-plane in sufficiently large magnetic fields that the moments are nearly parallel to one another. A complex angular dependence of the tunneling resistance is found with twofold and fourfold components that vary strongly with bias voltage. Distinctly different TAMR behaviors are obtained for devices formed with highly textured crystalline MgO(001) and amorphous Al₂O₃ tunnel barriers. A tight-binding model shows that a fourfold angular dependence can be explained by the presence of an interface resonant state that …

Forward-Jet Production In Deep Inelastic Ep Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi

Faculty Publications

Forward jet cross sections have been measured in neutral current deep inelastic scattering at low Bjorken-x with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb-1. Measurements are presented for inclusive forward jets as well as for forward jets accompanied by a dijet system. The explored phase space, with jet pseudorapidity up to 4.3 is expected to be particularly sensitive to the dynamics of QCD parton evolution at low x. The measurements are compared to fixed-order QCD calculations and to leading-order parton-shower Monte Carlo models. © 2007 Springer-Verlag / Società Italiana di Fisica.

Angular And Polarization Analysis Of X-Rays Emitted From Highly-Charged, Few-Electron Ions, Stephan Fritzsche, Andrey S. Surzhykov, Ulrich D. Jentschura, Th H. Stohlker

Physics Faculty Research & Creative Works

The recent theoretical progress in studying the x-ray emission from highly-charged, few-electron ions is reviewed. These case studies show that relativistic, high-Z ions provide a unique tool for better understanding the interplay between the electron-photon and electron-electron interactions in strong fields. Most naturally, this interplay is probed by the radiative capture of a (quasi-) free electron into the bound states of projectile ions, and by varying the charge state and the energy of the projectiles. For the capture into initially hydrogen-and lithium-like ions, here we summarize the recent results for the angular distribution and polarization of the recombination photons as …

Measurement And Evaluation Of Blade Passage Frequency Fluctuations (A), Cole V. Duke, Scott D. Sommerfeldt, Kent L. Gee, Connor R. Duke

Faculty Publications

In the active control of tonal noise from cooling fans, one factor that can limit the achievable attenuation is fluctuation of the blade passage frequency in time. Large fluctuations in a short time can hinder the algorithm from converging to the optimal solution. Some fans have steadier speeds than others, which can be due to unsteady driving mechanisms or the physical structure of the fan. Environmental effects, such as back pressure and unsteady blade loading, can also cause the fan speed to fluctuate. The shifting in the blade passage frequency will be measured using a zero-crossing technique to track the …

The Spin Axes Orbital Alignment Of Both Stars Within The Eclipsing Binary System V1143 Cyg Using The Rossiter-Mclaughlin Effect, S. Albrecht, S. Reffert, I. Snellen, A. Quirrenbach, D. S. Mitchell

Physics

Context. The Rossiter-McLaughlin (RM) effect, a rotational effect in eclipsing systems, provides unique insight into the relative orientation of stellar spin axes and orbital axes of eclipsing binary systems.

Aims. Our aim is to develop a robust method to analyze the RM effect in an eclipsing system with two nearly equally bright components. This gives access to the orientation of the stellar rotation axes and may shed light on questions of binary formation and evolution. For example, a misalignment between the spin axes and the angular momentum of the system could bring the observed and theoretical apsidal motion into better …

Vacancy Localization In The Square Dimer Model, Mark Bowick, J. Bouttier, Emmanuel Guitter, Monwhea Jeng

Physics - All Scholarship

We study the classical dimer model on a square lattice with a single vacancy by developing a graph-theoretic classification of the set of all configurations which extends the spanning tree formulation of close-packed dimers. With this formalism, we can address the question of the possible motion of the vacancy induced by dimer slidings. We find a probability 57/4-10Sqrt[2] for the vacancy to be strictly jammed in an infinite system. More generally, the size distribution of the domain accessible to the vacancy is characterized by a power law decay with exponent 9/8. On a finite system, the probability that a vacancy …

Isothermal Low-Field Tuning Of Exchange Bias In Epitaxial Fe/Cr2o3/Fe, Sarbeswar Sahoo, Tathagata Mukherjee, Kirill D. Belashchenko, Christian Binek

Christian Binek Publications

Moderate dc magnetic fields of less than 1 T allow tuning the exchange bias in an epitaxially grown Fe 10 nm/Cr₂O₃ 2.7 nm/Fe 10 nm trilayer between negative and positive bias fields. Remarkably, this tunable exchange bias is observed at least up to 395 K which exceeds the Néel temperature of bulk Cr₂O₃ (307 K). The presence of spontaneous exchange bias and the absence of training effects at room temperature suggest the existence of stable interface moments independent of antiferromagnetic long range order in Cr₂O₃. Furthermore, the coercivity remains constant, …

Ferroelectric Control Of Magnetism In Batio3/Fe Heterostructures Via Interface Strain Coupling, Sarbeswar Sahoo, Srinivas Polisetty, Chun-Gang Duan, Sitaram S. Jaswal, Evgeny Y. Tsymbal, Christian Binek

Christian Binek Publications

Reversible control of magnetism is reported for a Fe thin film in proximity of a BaTiO₃ single crystal. Large magnetization changes emerge in response to ferroelectric switching and structural transitions of BaTiO₃ controlled by applied electric fields and temperature, respectively. Interface strain coupling is the primary mechanism altering the induced magnetic anisotropy. As a result, coercivity changes up to 120% occur between the various structural states of BaTiO₃. Up to 20% coercivity change is achieved via electrical control at room temperature. Our all solid state ferroelectric-ferromagnetic heterostructures open viable possibilities for technological applications.

High-Et Dijet Photoproduction At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi

Faculty Publications

The cross section for high-ET dijet production in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 81.8pb-1. The events were required to have a virtuality of the incoming photon, Q2, of less than 1GeV2 and a photon-proton center-of-mass energy in the range 14215GeV and pseudorapidity (with respect to the proton beam direction) requirements of -1<ηjet1,2

G Factor Of The 2+1 State Of 170Hf, A. Wolf, Z. Berant, A. Heinz, V. Werner, E. A. Mccutchan, G. Gurdal, R. Cakirli, Y. Oktem, J. Ai, L. Amon, C. W. Beausang, D. S. Brenner, R. F. Casten, R. J. Casperson, K. Dusling, C. R. Fitzpatrick, A. B. Gransworthy, N. Pietralla, J. Qian, P. H. Regan, N. J. Thompson, E. Williams, R. Winkler

Physics Faculty Publications

The g factor of the 2⁺₁ state of ¹⁷⁰Hf was measured by perturbed γ-γ angular correlation in a static external magnetic field. The result, g(2⁺₁) = 0.28(5), extends the systematics of g factors of even-even Hf isotopes to N = 98 and enables a better test of theoretical models. The g(2⁺₁) experimental values of these isotopes exhibit a remarkable constancy as a function of neutron number. This phenomenon, which was also observed for other isotopic chains in the Gd–W range, is explained in terms of a recently proposed empirical …

Properties Of L = 1 B1 And B2* Mesons, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

This Letter presents the first strong evidence for the resolution of the excited B mesons B₁ and B₂^* as two separate states in fully reconstructed decays to B^+(*). The mass of B₁ is measured to be 5720.6 ± 2.4 ± 1.4 MeV=c ² and the mass difference ΔM between B₂^* and B₁ is 26.2 ± 3.1 ± 0.9 MeV/c ², giving the mass of the B₂^* as 5746.8 ± 2.4 ± 1.7 MeV/c ². The production rate for B₁ and B_{2 …}

Effect Of Tip Resonances On Tunnelling Anisotropic Magnetoresistance In Ferromagnetic Break Junctions: A First-Principles Study, John D. Burton, Renat F. Sabirianov, Julian P. Velev, O. N. Mryasov, Evgeny Y. Tsymbal

Materials Research Science and Engineering Center: Faculty Publications

First-principles calculations of electron tunneling transport in nanoscale Ni and Co break-junctions reveal strong dependence of the conductance on the magnetization direction, an effect known as tunneling anisotropic magnetoresistance TAMR. An important aspect of this phenomenon stems from resonant states localized in the electrodes near the junction break. The energy and broadening of these states is strongly affected by the magnetization orientation due to spin-orbit coupling, causing TAMR to be sensitive to bias voltage on a scale of a few millivolts. Our results bear a resemblance to recent experimental data and suggest that TAMR driven by resonant states is a …