Results for "N. Blagorodnova"

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A tale of two transients: GW170104 and GRB170105AMay 31 2017Jul 21 2017We present multi-wavelength follow-up campaigns by the AstroSat-CZTI and GROWTH collaborations to search for an electromagnetic counterpart to the gravitational wave event GW170104. At the time of the GW170104 trigger, the AstroSat CZTI field-of-view ... More
ZTF18aalrxas: A Type IIb Supernova from a very extended low-mass progenitorMar 21 2019We investigate ZTF18aalrxas, a double-peaked Type IIb core-collapse supernova (SN) discovered during science validation of the Zwicky Transient Facility (ZTF). ZTF18aalrxas was discovered while the optical emission was still rising towards the initial ... More
Far-Ultraviolet to Near-Infrared Spectroscopy of A Nearby Hydrogen Poor Superluminous Supernova Gaia16apdNov 09 2016Apr 17 2017We report the first maximum-light far-Ultraviolet to near-infrared spectra (1000A - 1.62um, rest) of a H-poor superluminous supernova, Gaia16apd. At z=0.1018, it is one of the closest and the UV brightest such events, with 17.4 (AB) magnitude in Swift ... More
A Fully Automated Integral Field Spectrograph Pipeline for the SEDMachine: pysedmFeb 22 2019Current time domain facilities are discovering hundreds of new galactic and extra-galactic transients every week. Classifying the ever-increasing number of transients is challenging, yet crucial to further our understanding of their nature, discover new ... More
Far-Ultraviolet to Near-Infrared Spectroscopy of A Nearby Hydrogen Poor Superluminous Supernova Gaia16apdNov 09 2016We report the first maximum-light far-Ultraviolet to near-infrared spectra (1000A - 1.62um, rest) of a H-poor superluminous supernova, Gaia16apd. At z=0.1018, it is one of the closest and the UV brightest such events, with 17.4 (AB) magnitude in Swift ... More
Revisiting optical tidal disruption events with iPTF16axaMar 03 2017May 15 2017We report the discovery by the intermediate Palomar Transient Factory (iPTF) of a candidate tidal disruption event (TDE) iPTF16axa at $z=0.108$, and present its broadband photometric and spectroscopic evolution from 3 months of follow-up observations ... More
Gaia16apd -- a link between fast-and slowly-declining type I superluminous supernovaeNov 30 2016We present ultraviolet, optical and infrared photometry and optical spectroscopy of the type Ic superluminous supernova (SLSN) Gaia16apd, covering its evolution from 27 d before the $g$-band peak to the nebular phase, including the latest spectrum ever ... More
Gaia16apd -- a link between fast-and slowly-declining type I superluminous supernovaeNov 30 2016Dec 01 2016We present ultraviolet, optical and infrared photometry and optical spectroscopy of the type Ic superluminous supernova (SLSN) Gaia16apd, covering its evolution from 27 d before the $g$-band peak to the nebular phase, including the latest spectrum ever ... More
The Death Throes of a Stripped Massive Star: An Eruptive Mass-Loss History Encoded in Pre-Explosion Emission, a Rapidly Rising Luminous Transient, and a Broad-Lined Ic Supernova SN2018gepApr 24 2019We present detailed observations of ZTF18abukavn (SN2018gep), discovered in high-cadence data from the Zwicky Transient Facility as a rapidly rising (1.3 mag/hr) and luminous ($M_{g,\mathrm{peak}}=-20$ mag) transient. It is spectroscopically classified ... More
OGLE-IV Real-Time Transient SearchSep 03 2014We present the design and first results of a real-time search for transients within the 650 sq. deg. area around the Magellanic Clouds, conducted as part of the OGLE-IV project and aimed at detecting supernovae, novae and other events. The average sampling ... More
Bright but slow - Type II supernovae from OGLE-IV - Implications for magnitude limited surveysJan 13 2015Feb 25 2015We study a sample of 11 Type II supernovae (SNe) discovered by the OGLE-IV survey. All objects have well sampled I-band light curves, and at least one spectrum. We find that 2 or 3 of the 11 SNe have a declining light curve, and spectra consistent with ... More
Gaia16apd -- a link between fast-and slowly-declining type I superluminous supernovaeNov 30 2016Jun 05 2017We present ultraviolet, optical and infrared photometry and optical spectroscopy of the type Ic superluminous supernova (SLSN) Gaia16apd (= SN 2016eay), covering its evolution from 26 d before the $g$-band peak to 234.1 d after the peak. Gaia16apd was ... More
iPTF17cw: An engine-driven supernova candidate discovered independent of a gamma-ray triggerMay 31 2017We present the discovery, classification, and radio-to-X-ray follow-up observations of iPTF17cw, a broad-lined (BL) type Ic supernova (SN) discovered by the intermediate Palomar Transient Factory (iPTF). Although unrelated to the gravitational wave trigger, ... More
A UV Resonance Line Echo from a Shell Around a Hydrogen-Poor Superluminous SupernovaAug 14 2018Aug 18 2018Hydrogen-poor superluminous supernovae (SLSN-I) are a class of rare and energetic explosions discovered in untargeted transient surveys in the past decade. The progenitor stars and the physical mechanism behind their large radiated energies ($\sim10^{51}$ ... More
Illuminating Gravitational Waves: A Concordant Picture of Photons from a Neutron Star MergerOct 16 2017Merging neutron stars offer an exquisite laboratory for simultaneously studying strong-field gravity and matter in extreme environments. We establish the physical association of an electromagnetic counterpart EM170817 to gravitational waves (GW170817) ... More
The Broad Absorption Line Tidal Disruption Event iPTF15af: Optical and Ultraviolet EvolutionSep 20 2018We present multiwavelength observations of the tidal disruption event (TDE) iPTF15af, discovered by the intermediate Palomar Transient Factory (iPTF) survey at redshift $z=0.07897$. The optical and ultraviolet (UV) light curves of the transient show a ... More
Early Observations of the Type Ia Supernova iPTF 16abc: A Case of Interaction with Nearby, Unbound Material and/or Strong Ejecta MixingAug 23 2017May 22 2018Early observations of Type Ia supernovae (SNe Ia) provide a unique probe of their progenitor systems and explosion physics. Here we report the intermediate Palomar Transient Factory (iPTF) discovery of an extraordinarily young SN Ia, iPTF 16abc. By fitting ... More
iPTF16asu: A Luminous, Rapidly-Evolving, and High-Velocity SupernovaJun 15 2017Jan 09 2018Wide-field surveys are discovering a growing number of rare transients whose physical origin is not yet well understood. Here, we present optical and UV data and analysis of iPTF16asu, a luminous, rapidly-evolving, high velocity, stripped-envelope supernova. ... More
Sifting for Sapphires: Systematic Selection of Tidal Disruption Events in iPTFDec 13 2017Aug 13 2018We present results from a systematic selection of tidal disruption events (TDEs) in a wide-area (4800~deg$^2$), $g+R$ band, Intermediate Palomar Transient Factory (iPTF) experiment. Our selection targets typical optically-selected TDEs: bright ($>$60\% ... More
iPTF Discovery of the Rapid "Turn On" of a Luminous QuasarDec 14 2016We present a radio-quiet quasar at z=0.237 discovered "turning on" by the intermediate Palomar Transient Factory (iPTF). The transient, iPTF 16bco, was detected by iPTF in the nucleus of a galaxy with an archival SDSS spectrum with weak narrow-line emission ... More
The OmegaWhite survey for short-period variable stars - V. Discovery of an ultracompact hot subdwarf binary with a compact companion in a 44 minute orbitOct 19 2017We report the discovery of the ultracompact hot subdwarf (sdOB) binary OW J074106.0-294811.0 with an orbital period of P$_{\rm orb}=44.66279\pm1.16\times10^{-4}$ min, making it the most compact hot subdwarf binary known. Spectroscopic observations using ... More
OGLE-2013-SN-079: a lonely supernova consistent with a helium shell detonationOct 22 2014Dec 17 2014We present observational data for a peculiar supernova discovered by the OGLE-IV survey and followed by the Public ESO Spectroscopic Survey for Transient Objects. The inferred redshift of $z=0.07$ implies an absolute magnitude in the rest-frame $I$-band ... More
iPTF16geu: A multiply imaged, gravitationally lensed type Ia supernovaOct 31 2016Apr 24 2017We report the discovery of a multiply-imaged gravitationally lensed Type Ia supernova, iPTF16geu (SN 2016geu), at redshift $z=0.409$. This phenomenon could be identified because the light from the stellar explosion was magnified more than fifty times ... More
Common Envelope ejection for a Luminous Red Nova in M101Jul 27 2016We present the results of optical, near-infrared, and mid-infrared observations of M101 OT2015-1 (PSN J14021678+5426205), a luminous red nova in M101 galaxy, spanning 16 years. The lightcurve of the object showed two peaks with absolute magnitudes $M_R\leq-12.4$ ... More
Common Envelope ejection for a Luminous Red Nova in M101Jul 27 2016Oct 28 2016We present the results of optical, near-infrared, and mid-infrared observations of M101 OT2015-1 (PSN J14021678+5426205), a luminous red transient in the Pinwheel galaxy (M101), spanning a total of 16 years. The lightcurve showed two distinct peaks with ... More
GS-TEC: the Gaia Spectrophotometry Transient Events ClassifierApr 28 2014We present an algorithm for classifying the nearby transient objects detected by the Gaia satellite. The algorithm will use the low-resolution spectra from the blue and red spectro-photometers on board of the satellite. Taking a Bayesian approach we model ... More
Discovery of Highly Blueshifted Broad Balmer and Metastable Helium Absorption Lines in a Tidal Disruption EventMar 13 2019We report the discovery of non-stellar hydrogen Balmer and metastable helium absorption lines accompanying a transient, high-velocity (0.05$c$) broad absorption line (BAL) system in the optical spectra of the tidal disruption event (TDE) AT2018zr ($z=0.071$). ... More
The discovery of the multiply-imaged lensed Type Ia supernova iPTF16geuOct 31 2016We report the discovery of a gravitationally lensed Type Ia supernova (SN Ia) by the intermediate Palomar Transient Factor (iPTF). The light originating from SNIa iPTF16geu, at redshift $z_{SN}=0.409$, is magnified by an intervening galaxy at $z_{l}=0.216$, ... More
iPTF Survey for Cool TransientsNov 28 2017Jan 12 2018We performed a wide-area (2000 deg$^{2}$) g and I band experiment as part of a two month extension to the Intermediate Palomar Transient Factory. We discovered 36 extragalactic transients including iPTF17lf, a highly reddened local SN Ia, iPTF17bkj, a ... More
A New Class of Changing-Look LINERsApr 24 2019We report the discovery of six active galactic nuclei (AGN) caught "turning on" during the first nine months of the Zwicky Transient Facility (ZTF) survey. The host galaxies were classified as LINERs by weak narrow forbidden line emission in their archival ... More
Gaia transient detection efficiency: hunting for nuclear transientsOct 27 2015We present a study of the detectability of transient events associated with galaxies for the Gaia European Space Agency astrometric mission. We simulated the on-board detections, and on-ground processing for a mock galaxy catalogue to establish the properties ... More
Black hole masses of tidal disruption event host galaxiesJun 27 2017The mass of the central black hole in a galaxy that hosted a tidal disruption event (TDE) is an important parameter in understanding its energetics and dynamics. We present the first homogeneously measured black hole masses of a complete sample of 12 ... More
iPTF16fnl: a faint and fast tidal disruption event in an E+A galaxyMar 02 2017May 25 2017We present ground-based and \textit{Swift} observations of iPTF16fnl, a likely tidal disruption event (TDE) discovered by the intermediate Palomar Transient Factory (iPTF) survey at 66.6 Mpc. The lightcurve of the object peaked at absolute $M_g=-17.2$ ... More
SN 2011ht: Weak explosion in massive extended envelopeOct 21 2015Oct 29 2015A possibility is explored to account for the light curve and the low expansion velocity of the supernova SN~2011ht, a member of group of three objects showing signatures of both IIn and IIP supernovae. It is argued that the radiated energy and the expansion ... More
Affine metrics and algebroid structures: Application to general relativity and unificationAug 14 2011Affine metrics and its associated algebroid bundle are developed. Theses structures are applied to the general relativity and provide an structure for unification of gravity and electromagnetism. The final result is a field equation on the associated ... More
$ΔS = 1$ Hadronic Weak Decays of Hyperons in a Soliton ModelSep 23 1997We study the parity violating hyperon non-leptonic weak decays in the three flavor Skyrme model. We follow the approach in which the symmetry breaking terms in the action are diagonalized exactly within the collective coordinate approximation. We show ... More
Fate of k_perp-factorization for hard processes in nuclear environmentDec 15 2004Large thickness of heavy nuclei brings in a new scale into the pQCD description of hard processes in nuclear environment. The familiar linear $k_{\perp}$-factorization breaks down and must be replaced by a new concept of the nonlinear $k_{\perp}$-factorization ... More
A statistical analysis of circumstellar material in Type Ia supernovaeAug 18 2013A key tracer of the elusive progenitor systems of Type Ia supernovae (SNe Ia) is the detection of narrow blueshifted time-varying Na I D absorption lines, interpreted as evidence of circumstellar material (CSM) surrounding the progenitor system. The origin ... More
Bosonic stimulation of cold 1s excitons into a harmonic potential minimum in Cu$_2$OFeb 07 2003Density distribution of cold exciton clouds generated into a strain-induced potential well by two-photon excitation in Cu$_2$O is studied at 2 K. We find that an anomalous spike, which can be interpreted as accumulation of the excitons into the ground ... More
The Universal Equation of State near the Critical Point of QCDJan 12 2004Jun 18 2004We study the universal properties of the phase diagram of QCD near the critical point using the exact renormalization group. For two-flavour QCD and zero quark masses we derive the universal equation of state in the vicinity of the tricritical point. ... More
Analytical Estimate of the Effect of Spherical Inhomogeneities on Luminosity Distance and RedshiftFeb 06 2008Jun 25 2008We provide an analytical estimate of the effect of a spherical inhomogeneity on light beams that travel through it. We model the interior of the inhomogeneity in terms of the Lemaitre-Tolman-Bondi metric. We assume that the beam source is located outside ... More
Heavy quark skyrmionsMay 18 2009The description of the heavy baryons as heavy-meson--soliton bound systems is reviewed. We outline how such bound systems arise from effective lagrangians that respect both chiral symmetry and heavy quark symmetry. Effects due to finite heavy quark masses ... More
Wind of presupernova IIn SN~1997egJan 15 2019Spectra and phototometry of type IIn supernova SN 1997eg are used to determine properties of the circumstellar gas lost by the presupernova during the latest 200 years before the explosion. The analysis of narrow H$\alpha$ and [Fe X] 6374 \AA\ results ... More
Connection between Diffraction and Small-$x$Nov 30 2001A brief review of the modern QCD theory of diffractive DIS is given.
Diffractive DIS: Where Are We?Nov 12 2001Nov 20 2001A brief review of the modern QCD theory of diffractive DIS is given. The recent progress has been remarkably rapid, all the principal predictions from the color dipole approach to diffraction - the $(Q^2+m_V^2)$ scaling, the pattern of SCHNC, shrinkage ... More
Diffractive Vector Mesons in DIS: Meson Structure and QCDSep 15 2000I review the modern status of QCD theory of diffractive vector meson production with the focus on shrinkage of photons with Q2 and (Q2+mV2)$scaling, j-plane properties of the QCD pomeron and Regge shrinkage of diffraction cone, $s$-channel helicity non-conservation ... More
Spin dependence of diffractive DISMay 31 1999I review the recent progress in the theory of s-channel helicity nonconservation (SCHNC) effects in diffractive DIS including the unitarity driven demise of the Burkhardt-Cottingham sum rule and strong scaling departure from the Wandzura-Wilczek relation. ... More
New upper bound for a class of vertex Folkman numbersJan 11 2006We improve the previuosly known bound for some vertex Folkman numbers.
Flow-invariant hypersurfaces in semi-dispersing billiardsMar 15 2006This work results from our attempts to solve Boltzmann-Sinai's hypothesis about the ergodicity of hard ball gases. A crucial element in the studies of the dynamics of hard balls is the analysis of special hypersurfaces in the phase space consisting of ... More
Effective quantum number for axially symmetric problemsAug 15 2014We generalize the universal effective quantum number introduced earlier for centrally symmetric problems. The proposed number determines the semiclassical quantization condition for axially symmetric potentials.
Propagation of a Dark Soliton in a Disordered Bose-Einstein CondensateJun 01 2005Sep 26 2005We consider the propagation of a dark soliton in a quasi 1D Bose-Einstein condensate in presence of a random potential. This configuration involves nonlinear effects and disorder, and we argue that, contrarily to the study of stationary transmission coefficients ... More
Unnatural Oscillon Lifetimes in an Expanding BackgroundApr 19 2006Jul 11 2006We consider a classical toy model of a massive scalar field in 1+1 dimensions with a constant exponential expansion rate of space. The nonlinear theory under consideration supports approximate oscillon solutions, but they eventually decay due to their ... More
Non-linear Matter Spectrum for a Variable Equation of StateFeb 17 2010Apr 10 2014We study the growth of matter perturbations beyond the linear level in cosmologies in which the dark energy has a variable equation of state. The non-linear corrections result in shifts in the positions of the maximum, minima and nodes of the spectrum ... More
Unifying aspects of polarization of vector mesons from hard production in DIS and at TevatronAug 08 2001Virtual photons have both the transverse and longitudinal polarization. In the inclusive DIS the impact of longitudinal photons, quantified by R=sigmaL/\igmaT sim 0.2, is marginal, but in diffractive DIS with excitation of small mass hadronic states or ... More
Cohomological invariants of a variation of flat connectionApr 20 2015Sep 23 2015In this paper, we apply the theory of Chern-Cheeger-Simons to construct canonical invariants associated to a $r$-simplex whose points parametrize flat connections on a smooth manifold $X$. These invariants lie in degrees $(2p-r-1)$-cohomology with $C/Z$-coefficients, ... More
Stability of tangent bundle on the moduli space of stable bundles on a curveNov 01 2011Feb 12 2014In this paper, we prove that the tangent bundle of the moduli space $\cSU_C(r,d)$ of stable bundles of rank $r>2$ and of fixed determinant of degree $d$ (such that $(r,d)=1$), on a smooth projective curve $C$ is always stable, in the sense of Mumford-Takemoto. ... More
Incomplete Tribonacci-Lucas numbers and polynomialsApr 16 2014In this paper, we define Tribonacci-Lucas polynomials and present Tribonacci-Lucas numbers and polynomials as a binomial sum. Then, we introduce incomplete Tribonacci-Lucas numbers and polynomials. In addition we derive recurrence relations, some properties ... More
Henon-Heiles Hamiltonian for Coupled Upper-Hybrid and Magnetoacoutic Waves in Magnetized PlasmasJul 24 1995We show that the coupled mode equations for the stationary propagation of upper--hybrid and magnetoacoustic waves in magnetized electron--ion plasmas with negative group dispersion can be exactly derived from the generalized \Henon--Heiles Hamiltonian. ... More
Circumstellar Na I and Ca II lines of type Ia supernovae in symbiotic scenarioJan 29 2008Formation of circumstellar lines of Na I and Ca II in type Ia supernovae is studied for the case, when supernova explodes in a binary system with a red giant. The model suggests a spherically-symmetric wind and takes into account ionization and heating ... More
Broad emission lines from opaque electron-scattering environment of SN 1998SJun 13 2001I propose that broad narrow-topped emission lines with full width at zero intensity >20000 km/s, seen in early-time spectra of SN 1998S, originate from a dense circumstellar gas and not from the supernova ejecta. The tremendous line width is the result ... More
Circumstellar interaction in type Ibn supernovae and SN 2006jcAug 05 2009I analyse peculiar properties of light curve and continua of enigmatic Ibn supernovae, including SN 2006jc, and argue in favour of the early strong circumstellar interaction. This interaction explains the high luminosity and fast flux rise of SN 1999cq, ... More
Light Scalar Mesons as Manifestation of Spontaneously Broken Chiral SymmetryJan 20 2010Attention is paid to the production mechanisms of light scalars that reveal their nature. We reveal the chiral shielding of the \sigma(600) meson. We show that the kaon loop mechanism of the \phi radiative decays, ratified by experiment, points to the ... More
Strong decays of P wave baryons in the $1/N_c$ expansionApr 18 2005The hadronic decays of non-strange negative parity baryons are analyzed in the framework of the 1/Nc expansion. A complete basis of spin-flavor operators for the pseudoscalar meson S and D partial wave amplitudes is established to order 1/Nc and the unknown ... More
Two and Three parametric regular generalizations of spherically symmetric and axially symmetric metricsNov 22 2002Regular generalizations of spherically and axially symmetric metrics and their properties are considered. Newton gravity law generalizations are reduced for null geodesic.
Stripes ordering in self-stratification experiments of binary and ternary granular mixturesApr 25 2000The self-stratification of binary and ternary granular mixtures has been experimentally investigated. Ternary mixtures lead to a particular ordering of the strates which was not accounted for in former explanations. Bouncing grains are found to have an ... More
Partition test and sexual motivation in male miceAug 02 2007Theoretical analysis of own and literature investigations of sexual motivation with the use of the partition test [Kudryavtseva, 1987, 1994] in male mice was carried out. It has been shown that appearance of a receptive female in the neighboring compartment ... More
Spin Dependence of Diffractive Vector Meson ProductionAug 24 1999Aug 26 1999I review the recent progress in the theory of s-channel helicity nonconservation (SCHNC) effects in diffractive DIS. SCHNC in diffractive vector meson production is an unique probe of the spin-orbit coupling and Fermi motion of quarks in vector mesons. ... More
Helicity Flip in Diffractive DISAug 26 1999I review new results on s-channel helicity nonconservation (SCHNC) in diffractive DIS. I discuss how by virtue of unitarity diffractive DIS gives rise to spin structure functions which were believed to vanish at x << 1. These include tensor polarization ... More
Asymptotic behaviour of the total cross section of p-p scattering and the Akeno cosmic ray dataApr 21 1993I present a new determination of the total cross section for proton-proton collisions from the recent Akeno results on absorption of the cosmic ray protons in the p-Air collisions. Extrapolation to the SSC energy suggests $\sigma_{tot}(p-p) \approx (160-170) ... More
Asymmetry of $^{56}$Ni ejecta and polarization in type IIP supernova 2004djAug 21 2006I study a problem, whether the asymmetry of a $^{56}$Ni ejecta that results in the asymmetry of the H$\alpha$ emission line at the nebular epoch of the type IIP supernova SN 2004dj is able also to account for the recently detected polarization of the ... More
Non-Abelian Lovelock-Born-Infeld Topological Black HolesSep 02 2009Oct 24 2009We present the asymptotically AdS solutions of the Einstein gravity with hyperbolic horizons in the presence of $So(n(n-1)/2-1, 1)$ Yang-Mills fields governed by the non-Abelian Born-Infeld lagrangian. We investigate the properties of these solutions ... More
Gaussian measures associated to the higher order conservation laws of the Benjamin-Ono equationSep 24 2011Jul 04 2012Inspired by the work of Zhidkov on the KdV equation, we perform a construction of weighted gaussian measures associated to the higher order conservation laws of the Benjamin-Ono equation. The resulting measures are supported by Sobolev spaces of increasing ... More
Stability of the Lepton-Flavor Mixing Matrix Against Quantum CorrectionsJun 24 1999Recent neutrino experiments suggest the strong evidences of tiny neutrino masses and the lepton-flavor mixing. Neutrino-oscillation solutions for the atmospheric neutrino anomaly and the solar neutrino deficit can determine the texture of neutrino mass ... More
Yukawa Interaction from a SUSY Composite ModelSep 04 1997We present a composite model that is based on non-perturbative effects of N=1 supersymmetric SU(N_C) gauge theory with N_f=N_C+1 flavors. In this model, we consider N_C=7, where all matter fields in the supersymmetric standard model, that is, quarks, ... More
Static Configurations of Dark Energy and Dark MatterSep 26 2005Dec 08 2005We study static configurations of dark matter coupled to a scalar field responsible for the dark energy of the Universe. The dark matter is modelled as a Fermi gas within the Thomas-Fermi approximation. The mass of the dark matter particles is a function ... More
Colour transparency: a novel test of QCD in nuclear interactionsApr 20 1993Colour transparency is a cute and indispensable property of QCD as the gauge theory of strong interaction. CT tests of QCD consist of production of the perturbative small-sized hadronic state and measuring the strngth of its non-perturbative diffraction ... More
Intrinsic $k_{\perp}$ in the pomeronMay 31 1999Aug 20 1999In a consistent QCD approach to diffractive DIS gluons in the pomeron have soft $z_{g}$ distribution and very broad intrinsic $k_{\perp}$ distribution. The latter has not yet been incorporated into diffractive Monte-Carlo generators (RAPGAP,....). I argue ... More
An example of a 16-vertex Folkman edge (3,4)-graph without 8-cliquesFeb 12 2006In this paper we prove a new upper bouhd on an edge Folkman number. In a previous paper we have proved that this bound is exact.
Invariant measure for a three dimensional nonlinear wave equationJul 10 2007We study the long time behavior of the subcritical (subcubic) defocussing nonlinear wave equation on the three dimensional ball, for random data of low regularity. We prove that for a large set of radial initial data in $\cap_{s<1/2} H^s(B(0,1))$ the ... More
Modified Gauss-Newton method in low-rank signal estimationMar 04 2018The paper is devoted to the solution of a weighted non-linear least-squares problem for low-rank signal estimation, which is related Hankel structured low-rank approximation problems. The solution is constructed by a modified weighted Gauss-Newton method. ... More
Decay $X(3872)\toπ^0π^+π^-$ and $S$-wave $D^0\bar D^0 \toπ^+π^-$ scattering lengthApr 04 2019The isospin-breaking decay $X(3872)\to(D^*\bar D+ \bar D^*D) \to\pi^0D\bar D\to\pi^0\pi^+\pi^-$ is discussed. In its amplitude there is a triangle logarithmic singularity, due to which the dominant contribution to $BR(X(3872)\to\pi^0\pi^+\pi^-)$ comes ... More
Spherical symmetric charged solution with cosmological constantNov 29 2007A spherically symmetric charged ideal fluid solution of Einstein field equation is given in the presence of the cosmological constant and two well known example of this type of solution is presented. If the matter is confined in a region, the exterior ... More
Survey of Gravity in Non-Commutative GeometryApr 28 2009We present a survey of the application of Cones' Non-Commutative Geometry to gravitation. Bases of the theory and Euclidian gravity models are reviewed. Then we discuss the problem of a Lorentzian generalization of the theory and review existing attempts ... More
Unified Model of Radio and X-Ray Emission of Nova CI Cam 1998Sep 08 2010A unified model is proposed for the radio and X-ray outburst of nova CI Cam 1998 which suggests the shock interaction of nova shell with the circumstellar gas. The spherical model is able to describe kinematics of the radio shell together with the evolution ... More
Combined SM Higgs Limits at the TevatronOct 18 2009We combine results from CDF and DO on direct searches for a standard model (SM) Higgs boson (H) in pbar-p collisions at the Fermilab Tevatron at sqrt{s}=1.96 TeV. Compared to the previous Higgs Tevatron combination, more data and new channels (WH to tau ... More
Nonperturbative renormalization-group approach to fermion systems in the two-particle-irreducible effective action formalismOct 18 2013Jan 24 2014We propose a nonperturbative renormalization-group (NPRG) approach to fermion systems in the two-particle-irreducible (2PI) effective action formalism, based on an exact RG equation for the Luttinger-Ward functional. This approach enables us to describe ... More
Effective action for superfluid Fermi systems in the strong-coupling limitDec 21 2004Oct 20 2005We derive the low-energy effective action for three-dimensional superfluid Fermi systems in the strong-coupling limit, where superfluidity originates from Bose-Einstein condensation of composite bosons. Taking into account density and pairing fluctuations ... More
Spin waves in the spiral phase of a doped antiferromagnet: a strong-coupling approachMay 03 2001We study spin fluctuations in the spiral phase of the two-dimensional Hubbard model at low doping on the basis of the spin-particle-hole coherent-state path integral. In the strong correlation limit, we obtain an analytical expression of the spin-wave ... More
Fermi liquid theory: a renormalization group point of viewApr 30 1996We show how Fermi liquid theory results can be systematically recovered using a renormalization group (RG) approach. Considering a two-dimensional system with a circular Fermi surface, we derive RG equations at one-loop order for the two-particle vertex ... More
On the Lie subalgebra of Killing-Milne and Killing-Cartan vector fields in Newtonian space-timeDec 18 2014The Galilean (and more generally Milne) invariance of Newtonian theory allows for Killing vector fields of a general kind, whereby the Lie derivative of a field is not required to vanish but only to be cancellable by some infinitesimal Galilean (respectively ... More
Evolutionary games on the lattice: Payoffs affecting birth and death ratesFeb 01 2013May 18 2015This article investigates an evolutionary game based on the framework of interacting particle systems. Each point of the square lattice is occupied by a player who is characterized by one of two possible strategies and is attributed a payoff based on ... More
Chiral four-body interactions in nuclear matterSep 20 2012An exploratory study of chiral four-nucleon interactions in nuclear and neutron matter is performed. The leading-order terms arising from pion-exchange in combination with the chiral $4\pi$-vertex and the chiral NN$3\pi$-vertex are found to be very small. ... More
Isovector part of nuclear energy density functional from chiral two- and three-nucleon forcesMar 28 2012A recent calculation of the nuclear energy density functional from chiral two- and three-nucleon forces is extended to the isovector terms pertaining to different proton and neutron densities. An improved density-matrix expansion is adapted to the situation ... More
Exact calculation of three-body contact interaction to second orderMar 28 2012For a system of fermions with a three-body contact interaction the second-order contributions to the energy per particle $\bar E(k_f)$ are calculated exactly. The three-particle scattering amplitude in the medium is derived in closed analytical form from ... More
Resummation of fermionic in-medium ladder diagrams to all ordersFeb 10 2011A system of fermions with a short-range interaction proportional to the scattering length $a$ is studied at finite density. At any order $a^n$, we evaluate the complete contributions to the energy per particle $\bar E(k_f)$ arising from combined (multiple) ... More
Radiative corrections to neutral pion-pair productionAug 04 2010We calculate the one-photon loop radiative corrections to the neutral pion-pair photoproduction process $\pi^-\gamma \to \pi^-\pi^0\pi^0$. At leading order this reaction is governed by the chiral pion-pion interaction. Since the chiral $\pi^+\pi^-\to\pi^0\pi^0$ ... More
Nuclear energy density functional from chiral pion-nucleon dynamics: Isovector termsMar 04 2010We extend a recent calculation of the nuclear energy density functional in the framework of chiral perturbation theory by computing the isovector surface and spin-orbit terms: $(\vec \nabla \rho_p- \vec \nabla \rho_n)^2 G_d(\rho)+ (\vec \nabla \rho_p- ... More
Pion-photon exchange nucleon-nucleon potentialsJan 31 2006We calculate in chiral perturbation theory the dominant next-to-leading order correction to the $\pi\gamma$-exchange NN-potential proportional to the large isovector magnetic moment $\kappa_v = 4.7$ of the nucleon. The corresponding spin-spin and tensor ... More
Dark matter vs. Pulsars: Catching the impostorSep 13 2013Sep 18 2013Evidence of excess GeV emission nearly coinciding with the Galactic Centre has been interpreted as a possible signature of annihilating dark matter. In this paper, we argue that it seems too early to discard pulsars as a viable explanation for the observed ... More
A Curious Source of Extended X-ray Emission in the Outskirts of Globular Cluster GLIMPSE-C01Nov 13 2009We report the discovery of an unusual source of extended X-ray emission CXOU J184846.3-013040 (`The Stem') located on the outskirts of the globular cluster GLIMPSE-C01. No point-like source falls within the extended emission which has an X-ray luminosity ... More