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Results for "J. Ayres"

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X-ray Emission from Young Stars in the TW Hya AssociationAug 18 2014The 9 Myr old TW Hya Association (TWA) is the nearest group (typical distances of $\sim$50 pc) of pre-main-sequence (PMS) stars with ages less than 10 Myr and contains stars with both actively accreting disks and debris disks. We have studied the coronal ... More
Coexistence of orbital and quantum critical magnetoresistance in FeSe$_{1-x}$S$_{x}$Mar 13 2019The recent discovery of a non-magnetic nematic quantum critical point (QCP) in the iron chalcogenide family FeSe$_{1-x}$S$_{x}$ has raised the prospect of investigating, in isolation, the role of nematicity on the electronic properties of correlated metals. ... More
Three-loop vacuum integrals with arbitrary massesSep 29 2016Nov 29 2016Three-loop vacuum integrals are an important building block for the calculation of a wide range of three-loop corrections. Until now, only results for integrals with one and two independent mass scales are known, but in the electroweak Standard Model ... More
Numerical multi-loop integrals and applicationsApr 01 2016Aug 12 2016Higher-order radiative corrections play an important role in precision studies of the electroweak and Higgs sector, as well as for the detailed understanding of large backgrounds to new physics searches. For corrections beyond the one-loop level and involving ... More
Three-loop vacuum integrals with arbitrary massesSep 29 2016Three-loop vacuum integrals are an important building block for the calculation of a wide range of three-loop corrections. Until now, only results for integrals with one and two independent mass scales are known, but in the electroweak Standard Model ... More
The satisfiability threshold for random linear equationsOct 20 2017Oct 15 2018Let $A$ be a random $m\times n$ matrix over the finite field $F_q$ with precisely $k$ non-zero entries per row and let $y\in F_q^m$ be a random vector chosen independently of $A$. We identify the threshold $m/n$ up to which the linear system $A x=y$ has ... More
Is the Sun Lighter than the Earth? Isotopic CO in the Photosphere, Viewed through the Lens of 3D Spectrum SynthesisJan 22 2013We consider the formation of solar infrared (2-6 micron) rovibrational bands of carbon monoxide (CO) in CO5BOLD 3D convection models, with the aim to refine abundances of the heavy isotopes of carbon (13C) and oxygen (18O,17O), to compare with direct ... More
Serendipitous X-ray Sources in the Chandra HRC Field around Alpha CentauriOct 27 2018For more than a decade, Alpha Centauri AB (G2V+K1V) has been observed by Chandra, in a long-term program to follow coronal (T~1MK) activity cycles of the two sunlike stars. Over 2008.4-2017.8, nineteen HRC-I exposures were taken, each about 10 ks in duration, ... More
Rigid colourings of hypergraphs and contiguityAug 13 2018We consider the problem of $q$-colouring a $k$-uniform random hypergraph, where $q,k \geq 3$, and determine the rigidity threshold. For edge densities above the rigidity threshold, we show that almost all solutions have a linear number of vertices that ... More
Renormalization and ultraviolet sensitivity of gauge vertices in universal extra dimensionsMay 30 2018When computing radiative corrections in models with compactified extra dimen- sions, one has to sum over the entire tower of Kaluza-Klein excitations inside the loops. The loop corrections generate a difference between the coupling strength of a zero-mode ... More
Anti-B --> X(s) gamma in two universal extra dimensionsJan 28 2008We calculate the leading order corrections to the anti-B --> X(s) gamma decay in the standard model with two large flat universal extra dimensions. We find that the contributions involving the exchange of Kaluza-Klein modes of the physical scalar field ... More
The Ups and Downs of Alpha CentauriJan 04 2014The following is a progress report on the long-term coronal activity of Alpha Centauri A (HD128620: G2V) and B (HD128621: K1V). Since 2005, Chandra X-ray Observatory has carried out semiannual pointings on AB, mainly with the High Resolution Camera (HRC-I), ... More
Gauge dependence and renormalization of $\tanβ$ in the MSSMMay 24 2002May 24 2004Well-known and newly developed renormalization schemes for $\tan\beta$ are analyzed in view of three desirable properties: gauge independence, process independence, and numerical stability in perturbation theory. Arguments are provided that no scheme ... More
Gauge dependence and renormalization of tan(beta)Oct 28 2002Renormalization schemes for tan(beta) are discussed in view of their gauge dependence. It is shown that several common renormalization schemes lead to a gauge-dependent definition of tan(beta), whereas two classes of gauge-independent schemes show even ... More
Higgs CP Properties From Early LHC DataNov 08 2012Mar 26 2013In this paper, we constrain CP violation in the Higgs sector using the measured signal strengths in the various Higgs search channels. To this end, we introduce a general parameterization for a resonance which is an admixture of a CP-even Higgs-like state ... More
The Far-Ultraviolet Ups and Downs of Alpha CentauriOct 31 2014Four years (2010-2014) of semiannual pointings by Hubble Space Telescope Imaging Spectrograph (STIS) on nearby Alpha Centauri have yielded a detailed time history of far-ultraviolet emissions of the solar-like primary (A: G2V) and the cooler, but more ... More
Cracking the Conundrum of F-Supergiant CoronaeFeb 07 2018Chandra X-ray and HST far-ultraviolet (FUV) observations of three early-F supergiants have shed new light on a previous puzzle involving a prominent member of the class: Alpha Persei (HD20902: F5Ib). The warm supergiant is a moderately strong, hard coronal ... More
Leptophilic Dark Matter in Lepton Interactions at LEP and ILCAug 08 2014Dark matter particles that couple primarily to leptons are only weakly constrained by data from direct detection experiments and the LHC. However, models of this kind necessarily generate effective four-lepton contact interactions at the tree- or one-loop-level, ... More
Two universal extra dimensions and spinless photons at the ILCNov 26 2007Mar 11 2008We study the ILC phenomenology of (1,0) Kaluza-Klein (KK) modes along two universal extra dimensions compactified on the chiral square. We compute production cross sections of various (1,0) particles at the ILC with sqrt(s)=1 TeV, focusing on decays of ... More
QCD corrections to massive color-octet vector boson pair productionJun 28 2017This paper describes the calculation of the next-to-leading order (NLO) QCD corrections to massive color-octet vector boson pair production at hadron colliders. As a concrete framework, a two-site coloron model with an internal parity is chosen, which ... More
Multi-Photon Signals from Composite Models at LHCOct 12 2010We analyze the collider signals of composite scalars that emerge in certain little Higgs models and models of vectorlike confinement. Similar to the decay of the pion into photon pairs, these scalars mainly decay through anomaly-induced interactions into ... More
The Flare-ona of EK DraconisMay 09 2015EK Draconis (HD 129333: G1.5 V) is a well-known young (50 Myr) solar analog. In 2012, Hubble Space Telescope returned to EK Dra to follow up a far-ultraviolet (FUV) SNAPshot visit by Cosmic Origins Spectrograph (COS) two years earlier. The brief SNAP ... More
Artificial Plants - Vascular Morphogenesis Controller-guided growth of braided structuresApr 17 2018Natural plants are exemplars of adaptation through self-organisation and collective decision making. As such, they provide a rich source of inspiration for adaptive mechanisms in artificial systems. Plant growth - a structure development mechanism of ... More
Comparison of JET main chamber erosion with dust collected in the divertorJul 26 2013A complete global balance for carbon in JET requires knowledge of the net erosion in the main chamber, net deposition in the divertor and the amount of dust and flakes collecting in the divertor region. This paper describes a number of measurements on ... More
FK Comae Berenices, King of Spin: The COCOA-PUFS ProjectJan 12 2016COCOA-PUFS is an energy-diverse, time-domain study of the ultra-fast spinning, heavily spotted, yellow giant FK Com (HD117555; G4 III). This single star is thought to be a recent binary merger, and is exceptionally active by measure of its intense ultraviolet ... More
On the Numerical Evaluation of Loop Integrals With Mellin-Barnes RepresentationsJan 19 2010An improved method is presented for the numerical evaluation of multi-loop integrals in dimensional regularization. The technique is based on Mellin-Barnes representations, which have been used earlier to develop algorithms for the extraction of ultraviolet ... More
Precise predictions for slepton pair productionNov 07 2002Mar 05 2003At a future linear collider, the masses and couplings of scalar leptons can be measured with high accuracy, thus requiring precise theoretical predictions for the relevant processes. In this work, after a discussion of the expected experimental precision, ... More
NOvA Proposal to Build a 30 Kiloton Off-Axis Detector to Study Neutrino Oscillations in the Fermilab NuMI BeamlineMar 30 2005This is an updated version of the NOvA proposal. The detector is a 30 kiloton tracking calorimeter, 15.7 m by 15.7 m by 132 m long, with alternating horizontal and vertical rectangular cells of liquid scintillator contained in PVC extrusion modules. Light ... More
Determining the SUSY-QCD Yukawa CouplingJun 09 2006Among the firm predictions of softly broken supersymmetry is the identity of gauge couplings and the corresponding Yukawa couplings between gauginos, sfermions and fermions. In the event that a SUSY-like spectrum of new particles is discovered at future ... More
Ultraviolet emission lines of Si II in cool star and solar spectraOct 29 2015Recent atomic physics calculations for Si II are employed within the Cloudy modelling code to analyse Hubble Space Telescope (HST) STIS ultraviolet spectra of three cool stars, Beta-Geminorum, Alpha-Centauri A and B, as well as previously published HST/GHRS ... More
A Multi-Wavelength Perspective of Flares on HR 1099: Four Years of Coordinated CampaignsFeb 25 2004We report on four years of multiple wavelength observations of the RS CVn system V711 Tau (HR 1099) from 1993, 1994, 1996, and 1998. This combination of radio, ultraviolet, extreme ultraviolet, and X-ray observations allows us to view, in the most comprehensive ... More
Hypergraph coloring up to condensationAug 07 2015Apr 13 2018Improving a result of Dyer, Frieze and Greenhill [Journal of Combinatorial Theory, Series B, 2015], we determine the $q$-colorability threshold in random $k$-uniform hypergraphs up to an additive error of $\ln 2+\varepsilon_q$, where $\lim_{q\to\infty}\varepsilon_q=0$. ... More
Matching Matters!Jul 27 2016Effective Lagrangians are a useful tool for a data-driven approach to physics beyond the Standard Model at the LHC. However, for the new physics scales accessible at the LHC, the effective operator expansion is only relatively slowly converging at best. ... More
Long-Slit Observations of Extended C II 1335 Emission Around V854 Centauri and RY SagittariiJun 28 2001We have obtained long-slit far-ultraviolet (1150--1730 A) spectra of the R Coronae Borealis (RCB) stars V854 Cen and RY Sgr, near maximum light and pulsational phase zero, with the Space Telescope Imaging Spectrograph (STIS) on Hubble Space Telescope ... More
Measuring Sparticles with the Matrix ElementOct 14 2009Oct 16 2009We apply the Matrix Element Method (MEM) to mass determination of squark pair production with direct decay to quarks and LSP at the LHC, showing that simultaneous mass determination of squarks and LSP is possible. We furthermore propose methods for inclusion ... More
Two-Loop Results for M_W in the Standard Model and the MSSMDec 04 2002Recent higher-order results for the prediction of the W-boson mass, M_W, within the Standard Model are reviewed and an estimate of the remaining theoretical uncertainties of the electroweak precision observables is given. An updated version of a simple ... More
Lower bounds on the chromatic number of random graphsDec 23 2018We prove that a formula predicted on the basis of non-rigorous physics arguments [Zdeborova and Krzakala: Phys. Rev. E (2007)] provides a lower bound on the chromatic number of sparse random graphs. The proof is based on the interpolation method from ... More
Computing Intrinsic Lyman-alpha Fluxes of F5 V to M5 V StarsJan 24 2013The Lyman-alpha emission line dominates the far-ultraviolet spectra of late-type stars and is a major source for photodissociation of important molecules including H2O, CH4, and CO2 in exoplanet atmospheres. The incident flux in this line illuminating ... More
Hypergraph coloring up to condensationAug 07 2015Improving a result of Dyer, Frieze and Greenhill [Journal of Combinatorial Theory, Series B, 2015], we determine the $q$-colorability threshold in random $k$-uniform hypergraphs up to an additive error of $\ln 2+\varepsilon_q$, where $\lim_{q\to\infty}\varepsilon_q=0$. ... More
Radiative corrections to masses and couplings in Universal Extra DimensionsNov 20 2017Feb 26 2018Models with an orbifolded universal extra dimension receive important loop-induced corrections to the masses and couplings of Kaluza-Klein (KK) particles. The dominant contributions stem from so-called boundary terms which violate KK number. Previously, ... More
Integrating in the Higgs Portal to Fermion Dark MatterJun 12 2015Jun 23 2015Fermion dark matter (DM) interacting with the standard model through a Higgs portal requires non-renormalizable operators, signaling the presence of new mediator states at the electroweak scale. Collider signatures that involve the mediators are a powerful ... More
Pushing Higgs Effective Theory to its LimitsOct 12 2015Jan 27 2016At the LHC, an effective theory of the Higgs sector allows us to analyze kinematic distributions in addition to inclusive rates, although there is no clear hierarchy of scales. We systematically analyze how well dimension-6 operators describe LHC observables ... More
Probing Light Dark Matter with a Hadrophilic Scalar MediatorDec 12 2018We investigate the thermal cosmology and terrestrial and astrophysical phenomenology of a sub-GeV hadrophilic dark sector. The specific construction explored in this work features a Dirac fermion dark matter candidate interacting with a light scalar mediator ... More
Measurement of the neutrino mass splitting and flavor mixing by MINOSMar 02 2011Measurements of neutrino oscillations using the disappearance of muon neutrinos from the Fermilab NuMI neutrino beam as observed by the two MINOS detectors are reported. New analysis methods have been applied to an enlarged data sample from an exposure ... More
The HST Treasury "Advanced Spectral Library" (ASTRAL) ProgramsNov 05 2014The "Advanced Spectral Library (ASTRAL)" Project (PI = T. Ayres) consists of two Treasury Programs: the Cycle 18 "Cool Stars" (GO-12278) Program and the Cycle 21 "Hot Stars" (GO-13346) Program. The primary goal of these programs is to collect, for the ... More
Axinos in Cosmology and at CollidersMay 05 2011The axino, the fermionic superpartner of the axion, is a well-motivated candidate for cold dark matter if it is the lightest supersymmetric particle. Since the axino couples very weakly to the matter multiplets, the next-to-lightest supersymmetric particle ... More
The two-loop electroweak bosonic corrections to $\sin^2θ_{\rm eff}^{\rm b}$Jul 28 2016Sep 30 2016The prediction of the effective electroweak mixing angle $\sin^2\theta_{\rm eff}^{\rm b}$ in the Standard Model at two-loop accuracy has now been completed by the first calculation of the bosonic two-loop corrections to the $Z{\bar b}b$ vertex. Numerical ... More
Chromospheric Thermal Continuum Millimetre Emission from non-dusty K and M Red GiantsOct 09 2012We examine the thermal free-free millimetre fluxes expected from non-dusty and non-pulsating K through mid-M giant stars based on our limited understanding of their inhomogeneous chromospheres. We present a semi-analytic model that provides estimates ... More
Upper Limits on the Peccei-Quinn Scale and on the Reheating Temperature in Axino Dark Matter ScenariosApr 21 2009Aug 21 2009Considering axino cold dark matter scenarios with a long-lived charged slepton, we study constraints on the Peccei-Quinn scale f_a and on the reheating temperature T_R imposed by the dark matter density and by big bang nucleosynthesis (BBN). For an axino ... More
Distinguishing spins in decay chains with photons at the Large Hadron ColliderApr 08 2009Aug 04 2009Several models for physics beyond the Standard Model predict new particles with a decay signature including hard photons and missing energy. Two well-motivated examples are supersymmetry with gauge-mediated breaking (GMSB) and the standard model with ... More
Flavor-specific scalar mediatorsDec 28 2017Oct 18 2018New singlet scalar bosons have broad phenomenological utility and feature prominently in many extensions of the Standard Model. Such scalars are often taken to have Higgs-like couplings to SM fermions in order to evade stringent flavor bounds, e.g. by ... More
Testing the Muon g-2 Anomaly at the LHCFeb 27 2014Sep 12 2014The long-standing difference between the experimental measurement and the standard-model prediction for the muon's anomalous magnetic moment, $a_{\mu} = (g_{\mu}-2)/2$, may be explained by the presence of new weakly interacting particles with masses of ... More
Constraining the Intrinsic Structure of Top-QuarksOct 09 2012Mar 21 2013The basic structure of top-quarks as spin-1/2 particles is characterized by the radius $R_t$ and the intrinsic magnetic dipole moment $\kappa_t$, both individually associated with gauge interactions. They are predicted to be zero in pointlike theories ... More
Complete electroweak two-loop corrections to Z boson production and decayApr 26 2018This article presents results for the last unknown two-loop contributions to the $Z$-boson partial widths and $Z$-peak cross-section. These are the so-called bosonic electroweak two-loop corrections, where "bosonic" refers to diagrams without closed fermion ... More
Ultraviolet Spectroscopy of Rapidly-Rotating Solar-Mass Stars: Emission Line Redshifts as a Test of the Solar-Stellar ConnectionMay 29 2012We compare high-resolution ultraviolet spectra of the Sun and thirteen solarmass main sequence stars with different rotational periods that serve as proxies for their different ages and magnetic field structures. In this the second paper in the series, ... More
Solar Carbon Monoxide, Thermal Profiling, and the Abundances of C, O, and their IsotopesJun 07 2006A solar photospheric "thermal profiling" analysis is presented, exploiting the infrared rovibrational bands of carbon monoxide (CO) as observed with the McMath-Pierce Fourier transform spectrometer (FTS) at Kitt Peak, and from above the Earth's atmosphere ... More
Invisible Z-Boson Decays at e+e- CollidersAug 05 2003The measurement of the invisible Z-boson decay width at e+e- colliders can be done "indirectly", by subtracting the Z-boson visible partial widths from the Z-boson total width, or "directly", from the process e+e- -> \gamma \nu \bar{\nu}. Both procedures ... More
Late Energy Injection and Cosmological Constraints in Axino Dark Matter ScenariosSep 17 2009Dec 14 2009Taking into account effects of late energy injection, we examine big bang nucleosynthesis (BBN) constraints on axino dark matter scenarios with long-lived charged sleptons. We calculate 4-body slepton decays into the axino, a lepton, and a quark-antiquark ... More
A Method for the Precision Mass Measurement of the Stop Quark at the International Linear ColliderDec 25 2007Many supersymmetric models predict new particles within the reach of the next generation of colliders. For an understanding of the model structure and the mechanism(s) of symmetry breaking, it is important to know the masses of the new particles precisely. ... More
Constraining the magnetic field on white dwarf surfaces; Zeeman effects and fine structure constant variationDec 30 2018White dwarf atmospheres are subjected to gravitational potentials around $10^5$ times larger than occur on Earth. They provide a unique environment in which to search for any possible variation in fundamental physics in the presence of strong gravitational ... More
Near-UV Absorption, Chromospheric Activity, and Star-Planet Interactions in the WASP-12 systemJan 09 2013Jan 25 2013We observed the extreme close-in hot Jupiter system WASP-12 with HST. Near-UV transits up to three times deeper than the optical transit of WASP-12b reveal extensive diffuse gas, extending well beyond the Roche lobe. The distribution of absorbing gas ... More
Absorbing gas around the WASP-12 planetary systemMar 14 2013Near-UV observations of the planet host star WASP-12 uncovered the apparent absence of the normally conspicuous core emission of the Mg2 h&k resonance lines. This anomaly could be due either to (1) a lack of stellar activity, which would be unprecedented ... More
Far Ultraviolet Continuum Emission: Applying this Diagnostic to the Chromospheres of Solar-Mass StarsSep 26 2011The far ultraviolet (FUV) continuum flux is recognized as a very sensitive diag- nostic of the temperature structure of the Sun's lower chromosphere. Until now analysis of the available stellar FUV data has shown that solar-type stars must also have chromospheres, ... More
Molecular absorption in transition region spectral linesSep 05 2014Aims: We present observations from the Interface Region Imaging Spectrograph (IRIS) of absorption features from a multitude of cool atomic and molecular lines within the profiles of Si IV transition region lines. Many of these spectral lines have not ... More
Lot sizing problem integrated with cutting stock problem in a paper industry: a multiobjective approachMar 08 2017Jul 18 2017In this work, we use a multiobjective approach to address the lot sizing problem integrated with the cutting stock problem in a paper industry. We analyze the trade-offs and correlations which exist among the costs and their decision variables. Considering ... More
SSALMON - The Solar Simulations for the Atacama Large Millimeter Observatory NetworkFeb 19 2015Apr 06 2015The Solar Simulations for the Atacama Large Millimeter Observatory Network (SSALMON) was initiated in 2014 in connection with two ALMA development studies. The Atacama Large Millimeter/submillimeter Array (ALMA) is a powerful new tool, which can also ... More
ALMA Observations of the Sun in Cycle 4 and BeyondJan 04 2016Apr 11 2016This document was created by the Solar Simulations for the Atacama Large Millimeter Observatory Network (SSALMON) in preparation of the first regular observations of the Sun with the Atacama Large Millimeter/submillimeter Array (ALMA), which are anticipated ... More
New Physics from the Top at the LHCJul 19 2012Dec 10 2012The top quark may hold the key to new physics associated with the electroweak symmetry-breaking sector, given its large mass and enhanced coupling to the Higgs sector. We systematically categorize generic interactions of a new particle that couples to ... More
Theory Requirements and Possibilities for the FCC-ee and other Future High Energy and Precision Frontier Lepton CollidersJan 09 2019The future lepton colliders proposed for the High Energy and Precision Frontier set stringent demands on theory. The most ambitious, broad-reaching and demanding project is the FCC-ee. We consider here the present status and requirements on precision ... More
Heavy Color-Octet Particles at the LHCOct 29 2014Jun 23 2015Many new-physics models, especially those with a color-triplet top-quark partner, contain a heavy color-octet state. The "naturalness" argument for a light Higgs boson requires that the color-octet state be not much heavier than a TeV, and thus it can ... More
A study of the elements copper through uranium in Sirius A: Contributions from STIS and ground-based spectraMay 26 2016We determine abundances or upper limits for all of the 55 stable elements from copper to uranium for the A1 Vm star Sirius. The purpose of the study is to assemble the most complete picture of elemental abundances with the hope of revealing the chemical ... More
The Structure of the Local Interstellar Medium. VI. New MgII, FeII, and MnII Observations Toward Stars Within 100 ParsecsMar 31 2014We analyze high-resolution spectra obtained with the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope toward 34 nearby stars (<100 pc) to record MgII, FeII and MnII absorption due to the local interstellar medium (LISM). Observations ... More
First measurement of electron neutrino appearance in NOvAJan 19 2016May 02 2016We report results from the first search for $\nu_\mu\to\nu_e$ transitions by the NOvA experiment. In an exposure equivalent to $2.74\times10^{20}$ protons-on-target in the upgraded NuMI beam at Fermilab, we observe 6 events in the Far Detector, compared ... More
First measurement of muon-neutrino disappearance in NOvAJan 19 2016Jan 20 2016This paper reports the first measurement using the NOvA detectors of $\nu_\mu$ disappearance in a $\nu_\mu$ beam. The analysis uses a 14 kton-equivalent exposure of $2.74 \times 10^{20}$ protons-on-target from the Fermilab NuMI beam. Assuming the normal ... More
The photospheric solar oxygen project: I. Abundance analysis of atomic lines and influence of atmospheric modelsMay 28 2008The solar oxygen abundance has undergone a major downward revision in the last decade, the most noticeable one being the update including 3D hydrodynamical simulations to model the solar photosphere. Up to now, such an analysis has been carried out only ... More
A Robot to Shape your Natural Plant: The Machine Learning Approach to Model and Control Bio-Hybrid SystemsApr 18 2018Apr 19 2018Bio-hybrid systems---close couplings of natural organisms with technology---are high potential and still underexplored. In existing work, robots have mostly influenced group behaviors of animals. We explore the possibilities of mixing robots with natural ... More
Observation of gravitationally induced vertical striation of polarized ultracold neutrons by spin-echo spectroscopyJun 01 2015Sep 08 2015We describe a spin-echo method for ultracold neutrons (UCNs) confined in a precession chamber and exposed to a $|B_0|=1~\text{\mu T}$ magnetic field. We have demonstrated that the analysis of UCN spin-echo resonance signals in combination with knowledge ... More
A Far Ultraviolet Spectroscopic Explorer Survey of Coronal Forbidden Lines in Late-Type StarsNov 15 2002We present a survey of coronal forbidden lines detected in Far Ultraviolet Spectroscopic Explorer (FUSE) spectra of nearby stars. Two strong coronal features, Fe XVIII 974 A and Fe XIX 1118 A, are observed in 10 of the 26 stars in our sample. Various ... More
The Advanced Spectral Library (ASTRAL): Reference Spectra for Evolved M-StarsNov 28 2018The HST Treasury Program "Advanced Spectral Library Project: Cool Stars" was designed to collect representative, high quality ultraviolet spectra of eight evolved F-M type cool stars. The Space Telescope Imaging Spectrograph (STIS) echelle spectra of ... More
Recent direct reaction experimental studies with radioactive tin beamsAug 26 2015Direct reaction techniques are powerful tools to study the single-particle nature of nuclei. Performing direct reactions on short-lived nuclei requires radioactive ion beams produced either via fragmentation or the Isotope Separation OnLine (ISOL) method. ... More
Characterising exoplanets and their environment with UV transmission spectroscopyMar 04 2015Exoplanet science is now in its full expansion, particularly after the CoRoT and Kepler space missions that led us to the discovery of thousands of extra-solar planets. The last decade has taught us that UV observations play a major role in advancing ... More
Cool, evolved stars: results, challenges, and promises for the next decadeMar 11 2019Cool, evolved stars are the main source of chemical enrichment of the interstellar medium (ISM), and understanding their mass loss and structure offers a unique opportunity to study the cycle of matter in the Universe. Pulsation, convection, and other ... More
The solar photospheric abundance of carbon.Analysis of atomic carbon lines with the CO5BOLD solar modelFeb 12 2010The use of hydrodynamical simulations, the selection of atomic data, and the computation of deviations from local thermodynamical equilibrium for the analysis of the solar spectra have implied a downward revision of the solar metallicity. We are in the ... More
Solar science with the Atacama Large Millimeter/submillimeter Array - A new view of our SunApr 26 2015Jan 04 2016The Atacama Large Millimeter/submillimeter Array (ALMA) is a new powerful tool for observing the Sun at high spatial, temporal, and spectral resolution. These capabilities can address a broad range of fundamental scientific questions in solar physics. ... More
Measurement of the atmospheric neutrino flavour composition in Soudan 2Nov 13 1996Nov 29 1996The atmospheric neutrino flavour ratio measured using a 1.52 kton-year exposure of Soudan 2 is found to be 0.72 +- 0.19 +0.05 -0.07 relative to the expected value from a Monte Carlo calculation. The possible background of interactions of neutrons and ... More
Isotope Harvesting at FRIB: Additional opportunities for scientific discoveryDec 07 2018The Facility for Rare Isotope Beams (FRIB) at Michigan State University provides a unique opportunity to access some of the nation's most specialized scientific resources: radioisotopes. An excess of useful radioisotopes will be formed as FRIB fulfills ... More
A Revised Experimental Upper Limit on the Electric Dipole Moment of the NeutronSep 15 2015Oct 13 2015We present for the first time a detailed and comprehensive analysis of the experimental results that set the current world sensitivity limit on the magnitude of the electric dipole moment (EDM) of the neutron. We have extended and enhanced our earlier ... More
Gravitational Depolarization of Ultracold Neutrons: Comparison with DataJun 22 2015Aug 26 2015We compare the expected effects of so-called gravitationally enhanced depolarization of ultracold neutrons to measurements carried out in a spin-precession chamber exposed to a variety of vertical magnetic-field gradients. In particular, we have investigated ... More
The extreme O-type spectroscopic binary HD 93129ANov 19 2018Jan 14 2019HD 93129A was classified as the earliest O-type star in the Galaxy (O2~If*) and is considered as the prototype of its spectral class. However, interferometry shows that this object is a binary system, while recent observations even suggest a triple configuration. ... More
Electronic and Structural Characteristics of Zinc-Blende Wurtzite Biphasic Homostructure GaN NanowiresFeb 16 2007We report a new biphasic crystalline wurtzite/zinc-blende homostructure in gallium nitride nanowires. Cathodoluminescence was used to quantitatively measure the wurtzite and zinc-blende band gaps. High resolution transmission electron microscopy was used ... More
Active to sterile neutrino mixing limits from neutral-current interactions in MINOSApr 20 2011Jul 01 2011Results are reported from a search for active to sterile neutrino oscillations in the MINOS long-baseline experiment, based on the observation of neutral-current neutrino interactions, from an exposure to the NuMI neutrino beam of $7.07\times10^{20}$ ... More
A Search for Lorentz Invariance and CPT Violation with the MINOS Far DetectorJul 16 2010We searched for a sidereal modulation in the MINOS far detector neutrino rate. Such a signal would be a consequence of Lorentz and CPT violation as described by the Standard-Model Extension framework. It also would be the first detection of a perturbative ... More
An improved measurement of muon antineutrino disappearance in MINOSFeb 13 2012We report an improved measurement of muon anti-neutrino disappearance over a distance of 735km using the MINOS detectors and the Fermilab Main Injector neutrino beam in a muon anti-neutrino enhanced configuration. From a total exposure of 2.95e20 protons ... More
First direct observation of muon antineutrino disappearanceApr 03 2011Aug 15 2011This letter reports the first direct observation of muon antineutrino disappearance. The MINOS experiment has taken data with an accelerator beam optimized for muon antineutrino production, accumulating an exposure of $1.71\times 10^{20}$ protons on target. ... More
Search for the disappearance of muon antineutrinos in the NuMI neutrino beamAug 06 2011Sep 20 2011We report constraints on antineutrino oscillation parameters that were obtained by using the two MINOS detectors to measure the 7% muon antineutrino component of the NuMI neutrino beam. In the Far Detector, we select 130 events in the charged-current ... More
Improved search for muon-neutrino to electron-neutrino oscillations in MINOSJul 29 2011We report the results of a search for $\nu_{e}$ appearance in a $\nu_{\mu}$ beam in the MINOS long-baseline neutrino experiment. With an improved analysis and an increased exposure of $8.2\times10^{20}$ protons on the NuMI target at Fermilab, we find ... More
Search for Lorentz invariance and CPT violation with muon antineutrinos in the MINOS Near DetectorJan 12 2012Jan 13 2012We have searched for sidereal variations in the rate of antineutrino interactions in the MINOS Near Detector. Using antineutrinos produced by the NuMI beam, we find no statistically significant sidereal modulation in the rate. When this result is placed ... More
The NuMI Neutrino BeamJul 23 2015Jul 29 2015This paper describes the hardware and operations of the Neutrinos at the Main Injector (NuMI) beam at Fermilab. It elaborates on the design considerations for the beam as a whole and for individual elements. The most important design details of individual ... More
Stability of spherical stellar systems I : Analytical resultsNov 22 1995The so-called ``symplectic method'' is used for studying the linear stability of a self-gravitating collisionless stellar system, in which the particles are also submitted to an external potential. The system is steady and spherically symmetric, and its ... More
Probing the Gravitational Dependence of the Fine-Structure Constant from Observations of White Dwarf StarsFeb 06 2017Apr 05 2017Hot white dwarf stars are the ideal probe for a relationship between the fine-structure constant and strong gravitational fields, providing us with an opportunity for a direct observational test. We study a sample of hot white dwarf stars, combining far-UV ... More