WorldWideScience

Sample records for discriminating strange star

  1. Discriminating strange star mergers from neutron star mergers by gravitational-wave measurements

    International Nuclear Information System (INIS)

    Bauswein, A.; Oechslin, R.; Janka, H.-T.

    2010-01-01

    We perform three-dimensional relativistic hydrodynamical simulations of the coalescence of strange stars and explore the possibility to decide on the strange matter hypothesis by means of gravitational-wave measurements. Self-binding of strange quark matter and the generally more compact stars yield features that clearly distinguish strange star from neutron star mergers, e.g. hampering tidal disruption during the plunge of quark stars. Furthermore, instead of forming dilute halo structures around the remnant as in the case of neutron star mergers, the coalescence of strange stars results in a differentially rotating hypermassive object with a sharp surface layer surrounded by a geometrically thin, clumpy high-density strange quark matter disk. We also investigate the importance of including nonzero temperature equations of state in neutron star and strange star merger simulations. In both cases we find a crucial sensitivity of the dynamics and outcome of the coalescence to thermal effects, e.g. the outer remnant structure and the delay time of the dense remnant core to black hole collapse depend on the inclusion of nonzero temperature effects. For comparing and classifying the gravitational-wave signals, we use a number of characteristic quantities like the maximum frequency during inspiral or the dominant frequency of oscillations of the postmerger remnant. In general, these frequencies are higher for strange star mergers. Only for particular choices of the equation of state the frequencies of neutron star and strange star mergers are similar. In such cases additional features of the gravitational-wave luminosity spectrum like the ratio of energy emitted during the inspiral phase to the energy radiated away in the postmerger stage may help to discriminate coalescence events of the different types. If such characteristic quantities could be extracted from gravitational-wave signals, for instance with the upcoming gravitational-wave detectors, a decision on the

  2. From strange stars to strange dwarfs

    International Nuclear Information System (INIS)

    Glendenning, N.K.; Kettner, C.; Weber, F.

    1995-01-01

    We determine all possible equilibrium sequences of compact strange-matter stars with nuclear crusts, which range from massive strange stars to strange white dwarf endash like objects (strange dwarfs). The properties of such stars are compared with those of their nonstrange counterparts emdash neutron stars and ordinary white dwarfs. The main emphasis of this paper is on strange dwarfs, which we divide into two distinct categories. The first one consists of a core of strange matter enveloped within ordinary white dwarf matter. Such stars are hydrostatically stable with or without the strange core and are therefore referred to as open-quote open-quote trivial close-quote close-quote strange dwarfs. This is different for the second category which forms an entirely new class of dwarf stars that contain nuclear material up to 4x10 4 times denser than in ordinary white dwarfs of average mass, M∼0.6 M circle-dot , and still about 400 times denser than in the densest white dwarfs. The entire family of such dwarfs, denoted dense strange dwarfs, owes its hydrostatic stability to the strange core. A striking features of strange dwarfs is that the entire sequence from the maximum-mass strange star to the maximum-mass strange dwarf is stable to radial oscillations. The minimum-mass star is only conditionally stable, and the sequences on both sides are stable. Such a stable, continuous connection does not exist between ordinary white dwarfs and neutron stars, which are known to be separated by a broad range of unstable stars. We find an expansive range of very low mass (planetary-like) strange-matter stars (masses even below 10 -4 M circle-dot are possible) that arise as natural dark-matter candidates, which if abundant enough in our Galaxy, should be seen in the gravitational microlensing searches that are presently being performed. copyright 1995 The American Astronomical Society

  3. Fast pulsars, strange stars

    International Nuclear Information System (INIS)

    Glendenning, N.K.

    1990-02-01

    The initial motivation for this work was the reported discovery in January 1989 of a 1/2 millisecond pulsar in the remnant of the spectacular supernova, 1987A. The status of this discovery has come into grave doubt as of data taken by the same group in February, 1990. At this time we must consider that the millisecond signal does not belong to the pulsar. The existence of a neutron star in remnant of the supernova is suspected because of recent observations on the light curve of the remnant, and of course by the neutrino burst that announced the supernova. However its frequency is unknown. I can make a strong case that a pulsar rotation period of about 1 ms divides those that can be understood quite comfortably as neutron stars, and those that cannot. What we will soon learn is whether there is an invisible boundary below which pulsar periods do not fall, in which case, all are presumable neutron stars, or whether there exist sub- millisecond pulsars, which almost certainly cannot be neutron stars. Their most plausible structure is that of a self-bound star, a strange-quark-matter star. The existence of such stars would imply that the ground state of the strong interaction is not, as we usually assume, hadronic matter, but rather strange quark matter. Let us look respectively at stars that are bound only by gravity, and hypothetical stars that are self-bound, for which gravity is so to speak, icing on the cake

  4. Stars of strange matter

    International Nuclear Information System (INIS)

    Bethe, H.A.; Brown, G.E.; Cooperstein, J.

    1987-01-01

    We investigate suggestions that quark matter with strangeness per baryon of order unity may be stable. We model this matter at nuclear matter densities as a gas of close packed Λ-particles. From the known mass of the Λ-particle we obtain an estimate of the energy and chemical potential of strange matter at nuclear densities. These are sufficiently high to preclude any phase transition from neutron matter to strange matter in the region near nucleon matter density. Including effects from gluon exchange phenomenologically, we investigate higher densities, consistently making approximations which underestimate the density of transition. In this way we find a transition density ρ tr > or approx.7ρ 0 , where ρ 0 is nuclear matter density. This is not far from the maximum density in the center of the most massive neutron stars that can be constructed. Since we have underestimated ρ tr and still find it to be ∝7ρ 0 , we do not believe that the transition from neutron to quark matter is likely in neutron stars. Moreover, measured masses of observed neutron stars are ≅1.4 M sun , where M sun is the solar mass. For such masses, the central (maximum) density is ρ c 0 . Transition to quark matter is certainly excluded for these densities. (orig.)

  5. Strange-quark-matter stars

    International Nuclear Information System (INIS)

    Glendenning, N.K.

    1989-11-01

    We investigate the implications of rapid rotation corresponding to the frequency of the new pulsar reported in the supernovae remnant SN1987A. It places very stringent conditions on the equation of state if the star is assumed to be bound by gravity alone. We find that the central energy density of the star must be greater than 13 times that of nuclear density to be stable against the most optimistic estimate of general relativistic instabilities. This is too high for the matter to consist of individual hadrons. We conclude that it is implausible that the newly discovered pulsar, if its half-millisecond signals are attributable to rotation, is a neutron star. We show that it can be a strange quark star, and that the entire family of strange stars can sustain high rotation if strange matter is stable at an energy density exceeding about 5.4 times that of nuclear matter. We discuss the conversion of a neutron star to strange star, the possible existence of a crust of heavy ions held in suspension by centrifugal and electric forces, the cooling and other features. 34 refs., 10 figs., 1 tab

  6. Strange matter in compact stars

    Science.gov (United States)

    Klähn, Thomas; Blaschke, David B.

    2018-02-01

    We discuss possible scenarios for the existence of strange matter in compact stars. The appearance of hyperons leads to a hyperon puzzle in ab-initio approaches based on effective baryon-baryon potentials but is not a severe problem in relativistic mean field models. In general, the puzzle can be resolved in a natural way if hadronic matter gets stiffened at supersaturation densities, an effect based on the quark Pauli quenching between hadrons. We explain the conflict between the necessity to implement dynamical chiral symmetry breaking into a model description and the conditions for the appearance of absolutely stable strange quark matter that require both, approximately masslessness of quarks and a mechanism of confinement. The role of strangeness in compact stars (hadronic or quark matter realizations) remains unsettled. It is not excluded that strangeness plays no role in compact stars at all. To answer the question whether the case of absolutely stable strange quark matter can be excluded on theoretical grounds requires an understanding of dense matter that we have not yet reached.

  7. Strange matter in compact stars

    Directory of Open Access Journals (Sweden)

    Klähn Thomas

    2018-01-01

    Full Text Available We discuss possible scenarios for the existence of strange matter in compact stars. The appearance of hyperons leads to a hyperon puzzle in ab-initio approaches based on effective baryon-baryon potentials but is not a severe problem in relativistic mean field models. In general, the puzzle can be resolved in a natural way if hadronic matter gets stiffened at supersaturation densities, an effect based on the quark Pauli quenching between hadrons. We explain the conflict between the necessity to implement dynamical chiral symmetry breaking into a model description and the conditions for the appearance of absolutely stable strange quark matter that require both, approximately masslessness of quarks and a mechanism of confinement. The role of strangeness in compact stars (hadronic or quark matter realizations remains unsettled. It is not excluded that strangeness plays no role in compact stars at all. To answer the question whether the case of absolutely stable strange quark matter can be excluded on theoretical grounds requires an understanding of dense matter that we have not yet reached.

  8. Torsional oscillations of strange stars

    Directory of Open Access Journals (Sweden)

    Mannarelli Massimo

    2014-01-01

    Full Text Available Strange stars are one of the hypothetical compact stellar objects that can be formed after a supernova explosion. The existence of these objects relies on the absolute stability of strange collapsed quark matter with respect to standard nuclear matter. We discuss simple models of strange stars with a bare quark matter surface, thus standard nuclear matter is completely absent. In these models an electric dipole layer a few hundreds Fermi thick should exist close to the star surface. Studying the torsional oscillations of the electrically charged layer we estimate the emitted power, finding that it is of the order of 1045 erg/s, meaning that these objects would be among the brightest compact sources in the heavens. The associated relaxation times are very uncertain, with values ranging between microseconds and minutes, depending on the crust thickness. Although part of the radiated power should be absorbed by the electrosphere surrounding the strange star, a sizable fraction of photons should escape and be detectable.

  9. Strange exotic states and compact stars

    International Nuclear Information System (INIS)

    Sagert, Irina; Wietoska, Mirjam; Schaffner-Bielich, Juergen

    2006-01-01

    We discuss the possible appearance of strange exotic multi-quark states in the interiors of neutron stars and signals for the existence of strange quark matter in the cores of compact stars. We show how the in-medium properties of possible pentaquark states are constrained by pulsar mass measurements. The possibility of generating the observed large pulsar kick velocities by asymmetric emission of neutrinos from strange quark matter in magnetic fields is outlined

  10. The Fastest Rotating Pulsar: a Strange Star?

    Institute of Scientific and Technical Information of China (English)

    徐仁新; 徐轩彬; 吴鑫基

    2001-01-01

    According to the observational limits on the radius and mass, the fastest rotating pulsar (PSR 1937+21) is probably a strange star, or at least some neutron star equations of state should be ruled out, if we suggest that a dipole magnetic field is relevant to its radio emission. We presume that the millisecond pulsar is a strange star with much low mass, small radius and weak magnetic moment.

  11. Quark core stars, quark stars and strange stars

    International Nuclear Information System (INIS)

    Grassi, F.

    1988-01-01

    A recent one flavor quark matter equation of state is generalized to several flavors. It is shown that quarks undergo a first order phase transition. In addition, this equation of state depends on just one parameter in the two flavor case, two parameters in the three flavor case, and these parameters are constrained by phenomenology. This equation of state is then applied to the hadron-quark transition in neutron stars and the determination of quark star stability, the investigation of strange matter stability and possible strange star existence. 43 refs., 6 figs

  12. Medium effects in strange quark matter and strange stars

    International Nuclear Information System (INIS)

    Schertler, K.; Greiner, C.; Thoma, M.H.

    1997-01-01

    We investigate the properties of strange quark matter at zero temperature including medium effects. The quarks are considered as quasiparticles which acquire an effective mass generated by the interaction with the other quarks of the dense system. The effective quark masses are derived from the zero momentum limit of the dispersion relations following from an effective quark propagator obtained from resumming one-loop self-energy diagrams in the hard dense loop approximation. This leads to a thermodynamic self-consistent description of strange quark matter as an ideal Fermi gas of quasiparticles. Within this approach we find that medium effects reduce the overall binding energy with respect to 56 Fe of strange quark matter. For typical values of the strong coupling constant (α s >or∼1) strange quark matter is not absolutely stable. The application to pure strange quark matter stars shows that medium effects have, nevertheless, no impact on the mass-radius relation of the stars. However, a phase transition to hadronic matter at the surface of the stars becomes more likely. (orig.)

  13. A new deterministic model of strange stars

    Energy Technology Data Exchange (ETDEWEB)

    Rahaman, Farook; Shit, G.C. [Jadavpur University, Department of Mathematics, Kolkata, West Bengal (India); Chakraborty, Koushik [Government Training College, Department of Physics, Hooghly, West Bengal (India); Kuhfittig, P.K.F. [Milwaukee School of Engineering, Department of Mathematics, Milwaukee, WI (United States); Rahman, Mosiur [Meghnad Saha Institute of Technology, Department of Mathematics, Kolkata (India)

    2014-10-15

    The observed evidence for the existence of strange stars and the concomitant observed masses and radii are used to derive an interpolation formula for the mass as a function of the radial coordinate. The resulting general mass function becomes an effective model for a strange star. The analysis is based on the MIT bag model and yields the energy density, as well as the radial and transverse pressures. Using the interpolation function for the mass, it is shown that a mass-radius relation due to Buchdahl is satisfied in our model. We find the surface redshift (Z) corresponding to the compactness of the stars. Finally, from our results, we predict some characteristics of a strange star of radius 9.9 km. (orig.)

  14. Relativistic model for anisotropic strange stars

    Science.gov (United States)

    Deb, Debabrata; Chowdhury, Sourav Roy; Ray, Saibal; Rahaman, Farook; Guha, B. K.

    2017-12-01

    In this article, we attempt to find a singularity free solution of Einstein's field equations for compact stellar objects, precisely strange (quark) stars, considering Schwarzschild metric as the exterior spacetime. To this end, we consider that the stellar object is spherically symmetric, static and anisotropic in nature and follows the density profile given by Mak and Harko (2002) , which satisfies all the physical conditions. To investigate different properties of the ultra-dense strange stars we have employed the MIT bag model for the quark matter. Our investigation displays an interesting feature that the anisotropy of compact stars increases with the radial coordinate and attains its maximum value at the surface which seems an inherent property for the singularity free anisotropic compact stellar objects. In this connection we also perform several tests for physical features of the proposed model and show that these are reasonably acceptable within certain range. Further, we find that the model is consistent with the energy conditions and the compact stellar structure is stable with the validity of the TOV equation and Herrera cracking concept. For the masses below the maximum mass point in mass vs radius curve the typical behavior achieved within the framework of general relativity. We have calculated the maximum mass and radius of the strange stars for the three finite values of bag constant Bg.

  15. FEROS Finds a Strange Star

    Science.gov (United States)

    1999-02-01

    New Spectrograph Explores the Skies from La Silla While a major effort is now spent on the Very Large Telescope and its advanced instruments at Paranal, ESO is also continuing to operate and upgrade the extensive research facilities at La Silla, its other observatory site. ESO PR Photo 03a/99 ESO PR Photo 03a/99 [Preview - JPEG: 800 x 1212 pix - 606k] [High-Res - JPEG: 1981 x 3000 pix - 3.6M] Caption to PR Photo 03a/99 : This photo shows the ESO 1.52-m telescope, installed since almost 30 years in its dome at the La Silla observatory in the southern Atacama desert. The new FEROS spectrograph is placed in an adjacent, thermally and humidity controlled room in the telescope building (where a classical coudé spectrograph was formerly located). The light is guided from the telescope to the spectrograph by 14-m long optical fibres. Within this programme, a new and powerful spectrograph, known as the Fibre-fed Extended Range Optical Spectrograph (FEROS) , has recently been built by a consortium of European institutes. It was commissioned in late 1998 at the ESO 1.52-m telescope by a small team of astronomers and engineers and has already produced the first, interesting scientific results. FEROS is able to record spectra of comparatively faint stars. For instance, it may be used to measure the chemical composition of stars similar to our Sun at distances of up to about 2,500 light-years, or to study motions in the atmospheres of supergiant stars in the Magellanic Clouds. These satellite galaxies to the Milky Way are more than 150,000 light-years away and can only be observed with telescopes located in the southern hemisphere. First FEROS observations uncover an unusual star ESO PR Photo 03b/99 ESO PR Photo 03b/99 [Preview - JPEG: 800 x 958 pix - 390k] [High-Res - JPEG: 3000 x 3594 pix - 1.7M] Caption to PR Photo 03b/99 : This diagramme shows the spectrum of the Lithium rich giant star S50 in the open stellar cluster Be21 , compared to that of a normal giant star ( S156

  16. Radial stability of anisotropic strange quark stars

    Energy Technology Data Exchange (ETDEWEB)

    Arbañil, José D.V.; Malheiro, M., E-mail: jose.arbanil@upn.pe, E-mail: malheiro@ita.br [ITA—Instituto Tecnológico de Aeronáutica—Departamento de Física, 12228-900, São José dos Campos, São Paulo (Brazil)

    2016-11-01

    The influence of the anisotropy in the equilibrium and stability of strange stars is investigated through the numerical solution of the hydrostatic equilibrium equation and the radial oscillation equation, both modified from their original version to include this effect. The strange matter inside the quark stars is described by the MIT bag model equation of state. For the anisotropy two different kinds of local anisotropic σ = p {sub t} − p {sub r} are considered, where p {sub t} and p {sub r} are respectively the tangential and the radial pressure: one that is null at the star's surface defined by p {sub r} ( R ) = 0, and one that is nonnull at the surface, namely, σ {sub s} = 0 and σ {sub s} {sub ≠} {sub 0}. In the case σ {sub s} = 0, the maximum mass value and the zero frequency of oscillation are found at the same central energy density, indicating that the maximum mass marks the onset of the instability. For the case σ {sub s} {sub ≠} {sub 0}, we show that the maximum mass point and the zero frequency of oscillation coincide in the same central energy density value only in a sequence of equilibrium configurations with the same value of σ {sub s} . Thus, the stability star regions are determined always by the condition dM / d ρ {sub c} {sub >} {sub 0} only when the tangential pressure is maintained fixed at the star surface's p {sub t} ( R ). These results are also quite important to analyze the stability of other anisotropic compact objects such as neutron stars, boson stars and gravastars.

  17. Strangeness in nuclei and neutron stars

    Science.gov (United States)

    Lonardoni, Diego

    2017-01-01

    The presence of exotic particles in the core of neutron stars (NS) has been questioned for a long time. At present, it is still an unsolved problem that drives intense research efforts, both theoretical and experimental. The appearance of strange baryons in the inner regions of a NS, where the density can exceed several times the nuclear saturation density, is likely to happen due to energetic considerations. The onset of strange degrees of freedom is considered as an effective mechanism to soften the equation of state (EoS). This softening affects the entire structure of the star, reducing the pressure and therefore the maximum mass that the star can stably support. The observation of two very massive NS with masses of the order of 2M⊙ seems instead to rule out soft EoS, apparently excluding the possibility of hyperon formation in the core of the star. This inconsistency, usually referred to as the hyperon puzzle, is based on what we currently know about the interaction between strange particles and normal nucleons. The combination of a poor knowledge of the hypernuclear interactions and the difficulty of obtaining clear astrophysical evidence of the presence of hyperons in NS makes the understanding of the behavior of strange degrees of freedom in NS an intriguing theoretical challenge. We give our contribution to the discussion by studying the general problem of the hyperon-nucleon interaction. We attack this issue by employing a quantum Monte Carlo (QMC) technique, that has proven to be successful in the description of strongly correlated Fermion systems, to the study of finite size nuclear systems including strange degrees of freedom, i.e. hypernuclei. We show that many-body hypernuclear forces are fundamental to properly reproduce the ground state physics of Λ hypernuclei from light- to medium-heavy. However, the poor abundance of experimental data on strange nuclei leaves room for a good deal of indetermination in the construction of hypernuclear

  18. On the Stability of Strange Dwarf Hybrid Stars

    Energy Technology Data Exchange (ETDEWEB)

    Alford, Mark G.; Harris, Steven P. [Physics Department, Washington University, St. Louis, MO 63130 (United States); Sachdeva, Pratik S., E-mail: harrissp@wustl.edu [Department of Physics, University of California, Berkeley, CA 94720 (United States)

    2017-10-01

    We investigate the stability of “strange dwarfs”: white-dwarf-sized stars with a density discontinuity between a small dense core of quark matter and a thick low-density mantle of degenerate electrons. Previous work on strange dwarfs suggested that such a discontinuity could stabilize stars that would have been classified as unstable by the conventional criteria based on extrema in the mass–radius relation. We investigate the stability of such stars by numerically solving the Sturm–Liouville equations for the lowest-energy modes of the star. We find that the conventional criteria are correct, and strange dwarfs are not stable.

  19. Role of strangeness to the neutron star mass and cooling

    Science.gov (United States)

    Lee, Chang-Hwan; Lim, Yeunhwan; Hyun, Chang Ho; Kwak, Kyujin

    2018-01-01

    Neutron star provides unique environments for the investigation of the physics of extreme dense matter beyond normal nuclear saturation density. In such high density environments, hadrons with strange quarks are expected to play very important role in stabilizing the system. Kaons and hyperons are the lowest mass states with strangeness among meson and bayron families, respectively. In this work, we investigate the role of kaons and hyperons to the neutron star mass, and discuss their role in the neutron star cooling.

  20. PSR1987A: the case for strange-quark stars

    International Nuclear Information System (INIS)

    Glendenning, N.K.

    1989-01-01

    The new fast pulsar observed in the remnant of SN1987A, together with other considerations, provide evidence that there are two types of collapsed stars: neutron stars, having moderate central densities and subject to the usual mass constraint, and strange-quark-matter stars. We show that (i) all known pulsar masses and frequencies, with the exception of the new one, can be accounted for by plausible neutron star models; (ii) no known neutron star model can withstand the fast rotation of the new pulsar unless the central energy density is ∼ 15 that of normal nuclei, at which densities hadrons cannot plausibly exist as constituents; and (iii) if strange-quark matter is the true ground state of the strong interactions, strange-quark stars can sustain the high rotation imputed to the new pulsar. In the absence of another plausible structure that can withstand the fast rotation, we provisionally infer that the new pulsar is such a star. (author)

  1. Cooling Curve of Strange Star in Strong Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-Qin; LUO Zhi-Quan

    2008-01-01

    In this paper, firstly, we investigate the neutrino emissivity from quark Urca process in strong magnetic field. Then, we discuss the heat capacity of strange stars in strong magnetic field. Finally, we give the cooling curve in strong magnetic field. In order to make a comparison, we also give the corresponding cooling curve in the case of null magnetic field. It turns out that strange stars cool faster in strong magnetic field than that without magnetic field.

  2. Thermal structure of accreting neutron stars and strange stars

    International Nuclear Information System (INIS)

    Miralda-Escude, J.; Paczynski, B.; Haensel, P.

    1990-01-01

    Steady-state models of accreting neutron stars and strange stars are presented, and their properties as a function of accretion rate are analyzed. The models have steady-state envelopes, with stationary hydrogen burning taken into account, the helium shell flashes artificially suppressed, and the crust with a large number of secondary heat sources. The deep interiors are almost isothermal and are close to thermal equilibrium. A large number of models were calculated for many values of the accretion rates, with ordinary, pion-condensed, and strange cores, with and without secondary heat sources in the crust, and with the heavy element content of the accreting matter in the range Z = 0.0002-0.02. All models show a similar pattern of changes as the accretion rate is varied. For low accretion rates, the hydrogen burning shell is unstable; for intermediate rates, the hydrogen burning shell is stable, but helium burning is not; for high rates, the two shell sources burn together and are unstable. 60 refs

  3. Role of strangeness to the neutron star mass and cooling

    Directory of Open Access Journals (Sweden)

    Lee Chang-Hwan

    2018-01-01

    Full Text Available Neutron star provides unique environments for the investigation of the physics of extreme dense matter beyond normal nuclear saturation density. In such high density environments, hadrons with strange quarks are expected to play very important role in stabilizing the system. Kaons and hyperons are the lowest mass states with strangeness among meson and bayron families, respectively. In this work, we investigate the role of kaons and hyperons to the neutron star mass, and discuss their role in the neutron star cooling.

  4. Dark matter, neutron stars, and strange quark matter.

    Science.gov (United States)

    Perez-Garcia, M Angeles; Silk, Joseph; Stone, Jirina R

    2010-10-01

    We show that self-annihilating weakly interacting massive particle (WIMP) dark matter accreted onto neutron stars may provide a mechanism to seed compact objects with long-lived lumps of strange quark matter, or strangelets, for WIMP masses above a few GeV. This effect may trigger a conversion of most of the star into a strange star. We use an energy estimate for the long-lived strangelet based on the Fermi-gas model combined with the MIT bag model to set a new limit on the possible values of the WIMP mass that can be especially relevant for subdominant species of massive neutralinos.

  5. Mass-radius relation for magnetized strange quark stars

    CERN Document Server

    Martinez, A Perez; Paret, D Manreza

    2010-01-01

    We review the stability of magnetized strange quark matter (MSQM) within the phenomenological MIT bag model, taking into account the variation of the relevant input parameters, namely, the strange quark mass, baryon density, magnetic field and bag parameter. A comparison with magnetized asymmetric quark matter in $\\beta$-equilibrium as well as with strange quark matter (SQM) is presented. We obtain that the energy per baryon for MSQM decreases as the magnetic field increases, and its minimum value at vanishing pressure is lower than the value found for SQM, which implies that MSQM is more stable than non-magnetized SQM. The mass-radius relation for magnetized strange quark stars is also obtained in this framework.

  6. Effects of Density-Dependent Bag Constant and Strange Star Rotation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Qiao-Er; GUO Hua

    2003-01-01

    With the emphasis on the effects of the density-dependent bag constant and the rotation of strange star the limiting mass of strange star is calculated. The obtained results show that the limiting mass and the corresponding radius of strange star increase as the rotation frequency increases, and tend to be lowered when the density-dependent bag constant is considered.

  7. Effect of the Curved Spacetime on the Electrostatic Potential Energy Distribution of Strange Stars

    Institute of Scientific and Technical Information of China (English)

    陈次星; 张家铝

    2001-01-01

    The effect of the strong gravitational field of the strange core of a strange star on its surface electrostatic potential energy distribution is discussed. We present the general-relativistic hydrodynamics equations of fluids in the presence of the electric fields and investigate the surface electrostatic potential distribution of the strange core of a strange star in hydrostatic equilibrium to correct Alcock and coworker's result [Astrophys. J. 310 (1986) 261]. Also, we discuss the temperature distribution of the bare strange star surface and give the related formulae, which may be useful if we are concerned further about the physical processes near the quark atter surfaces of strange stars.

  8. Dark matter admixed strange quark stars in the Starobinsky model

    Science.gov (United States)

    Lopes, Ilídio; Panotopoulos, Grigoris

    2018-01-01

    We compute the mass-to-radius profiles for dark matter admixed strange quark stars in the Starobinsky model of modified gravity. For quark matter, we assume the MIT bag model, while self-interacting dark matter inside the star is modeled as a Bose-Einstein condensate with a polytropic equation of state. We numerically integrate the structure equations in the Einstein frame, adopting the two-fluid formalism, and we treat the curvature correction term nonperturbatively. The effects on the properties of the stars of the amount of dark matter as well as the higher curvature term are investigated. We find that strange quark stars (in agreement with current observational constraints) with the highest masses are equally affected by dark matter and modified gravity.

  9. Properties of bare strange stars associated with surface electric fields

    International Nuclear Information System (INIS)

    Picanco Negreiros, Rodrigo; Mishustin, Igor N.; Schramm, Stefan; Weber, Fridolin

    2010-01-01

    In this paper we investigate the electrodynamic surface properties of bare strange quark stars. The surfaces of such objects are characterized by the formation of ultrahigh electric surface fields which might be as high as ∼10 19 V/cm. These fields result from the formation of electric dipole layers at the stellar surfaces. We calculate the increase in gravitational mass associated with the energy stored in the electric dipole field, which turns out to be only significant if the star possesses a sufficiently strong net electric charge distribution. In the second part of the paper, we explore the intriguing possibility of what happens when the electron layer (sphere) rotates with respect to the stellar strange matter body. We find that in this event magnetic fields can be generated which, for moderate effective rotational frequencies between the electron layer and the stellar body, agree with the magnetic fields inferred for several central compact objects. These objects could thus be comfortably interpreted as strange stars whose electron atmospheres rotate at frequencies that are moderately different (∼10 Hz) from the rotational frequencies of the strange star itself.

  10. On relativistic models of strange stars

    Indian Academy of Sciences (India)

    tractable models of superdense stars in equilibrium. Several aspects of physical relevance of compact star models, based on Vaidya–Tikekar ansatz, have been in- vestigated [7–10] by a number of workers. Mukherjee et al [11–13] indicated the possibility of using this set-up to describe models of the compact star like Her.

  11. Strange Stars: Can Their Crust Reach the Neutron Drip Density?

    Institute of Scientific and Technical Information of China (English)

    Hai Fu; Yong-Feng Huang

    2003-01-01

    The electrostatic potential of electrons near the surface of static strange stars at zero temperature is studied within the frame of the MIT bag model. We find that for QCD parameters within rather wide ranges, if the nuclear crust on the strange star is at a density leading to neutron drip, then the electrostatic potential will be insufficient to establish an outwardly directed electric field, which is crucial for the survival of such a crust. If a minimum gap width of 200 fm is brought in as a more stringent constraint, then our calculations will completely rule out the possibility of such crusts. Therefore, our results argue against the existence of neutron-drip crusts in nature.

  12. "Movie Star" Acting Strangely, Radio Astronomers Find

    Science.gov (United States)

    1999-01-01

    Astronomers have used the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope to make the first-ever time-lapse "movie" showing details of gas motions around a star other than our Sun. The study, the largest observational project yet undertaken using Very Long Baseline Interferometry, has produced surprising results that indicate scientists do not fully understand stellar atmospheres. The "movie" shows that the atmosphere of a pulsating star more than 1,000 light-years away continues to expand during a part of the star's pulsation period in which astronomers expected it to start contracting. Philip Diamond and Athol Kemball, of the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, announced their findings at the American Astronomical Society's meeting in Austin, TX, today. "The continued expansion we're seeing contradicts current theoretical models for how these stars work," Diamond said. "The models have assumed spherical symmetry in the star's atmosphere, and our movie shows that this is not the case. Such models suggest that a shock wave passes outward from the star. Once it's passed, then the atmosphere should begin to contract because of the star's gravity. We've long passed that point and the contraction has not begun." The time-lapse images show that the gas motions are not uniform around the star. Most of the motion is that of gas moving directly outward from the star's surface. However, in about one-fourth of the ring, there are peculiar motions that do not fit this pattern. The scientists speculate that the rate of mass loss may not be the same from all parts of the star's surface. "A similar star behaved as predicted when studied a few years ago, so we're left to wonder what's different about this one," Diamond said. "Right now, we think that different rates of mass loss in the two stars may be the cause of the difference. This star is losing mass at 100 times the rate of the star in the earlier study." "This

  13. White dwarf stars as strange quark matter detectors

    Energy Technology Data Exchange (ETDEWEB)

    Benvenuto, O G [Departamento de AstronomIa y AstroFisica, Pontificia Universidad Catolica, Vicuna Mackenna 4860, Casilla 306, Santiago (Chile); Facultad de Ciencias Astronomicas y GeoFisicas, Universidad Nacional de La Plata, Paseo del Bosque S/N, B1900FWA, La Plata (Argentina)

    2005-11-01

    We show that the presence of a strange matter core inside a white dwarf (WD) star produces a drastic change in the spectrum of non-radial oscillations in the range of periods corresponding to gravity modes. The distinctive, observable signal for such a core is a very short period spacing between consecutive modes, far shorter than in the case of pulsating WDs without any compact core. (letter to the editor)

  14. Strange stars in f(R,Script T) gravity

    Science.gov (United States)

    Deb, Debabrata; Rahaman, Farook; Ray, Saibal; Guha, B. K.

    2018-03-01

    In this article we try to present spherically symmetric isotropic strange star model under the framework of f(R,Script T) theory of gravity. To this end, we consider that the Lagrangian density is a linear function of the Ricci scalar R and the trace of the energy momentum tensor Script T given as f(R,Script T)=R+2χ Script T. We also assume that the quark matter distribution is governed by the simplest form of the MIT bag model equation of state (EOS) as p=1/3(ρ‑4B), where B is the bag constant. We have obtained an exact solution of the modified form of the Tolman-Oppenheimer-Volkoff (TOV) equation in the framework of f(R,Script T) gravity theory and have studied the dependence of different physical properties, viz., the total mass, radius, energy density and pressure for the chosen values of χ. Further, to examine physical acceptability of the proposed stellar model, we have conducted different tests in detail, viz., the energy conditions, modified TOV equation, mass-radius relation, causality condition etc. We have precisely explained the effects arising due to the coupling of the matter and geometry on the compact stellar system. For a chosen value of the bag constant, we have predicted numerical values of the different physical parameters in tabular form for the different strange star candidates. It is found that as the factor χ decreases the strange star candidates become gradually massive and larger in size with less dense stellar configuration. However, when χ increases the stars shrink gradually and become less massive to turn into a more compact stellar system. Hence for χ>0 our proposed model is suitable to explain the ultra-dense compact stars well within the observational limits and for χ<0 case allows to represent the recent massive pulsars and super-Chandrasekhar stars. For χ=0 we retrieve as usual the standard results of the general relativity (GR).

  15. COALESCENCE OF STRANGE-QUARK PLANETS WITH STRANGE STARS: A NEW KIND OF SOURCE FOR GRAVITATIONAL WAVE BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Geng, J. J.; Huang, Y. F. [School of Astronomy and Space Science, Nanjing University, Nanjing 210046 (China); Lu, T., E-mail: hyf@nju.edu.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2015-05-01

    Strange-quark matter (SQM) may be the true ground state of hadronic matter, indicating that the observed pulsars may actually be strange stars (SSs), but not neutron stars. According to the SQM hypothesis, the existence of a hydrostatically stable sequence of SQM stars has been predicted, ranging from 1 to 2 solar mass SSs, to smaller strange dwarfs and even strange planets. While gravitational wave (GW) astronomy is expected to open a new window to the universe, it will shed light on the search for SQM stars. Here we show that due to their extreme compactness, strange planets can spiral very close to their host SSs without being tidally disrupted. Like inspiraling neutron stars or black holes, these systems would serve as new sources of GW bursts, producing strong GWs at the final stage. The events occurring in our local universe can be detected by upcoming GW detectors, such as Advanced LIGO and the Einstein Telescope. This effect provides a unique probe to SQM objects and is hopefully a powerful tool for testing the SQM hypothesis.

  16. Softness of Nuclear Matter and the Production of Strange Particles in Neutron Stars

    Institute of Scientific and Technical Information of China (English)

    陈伟; 文德华; 刘良钢

    2003-01-01

    In the various models, we study the influences of the softness of nuclear matter, the vacuum fluctuation ofnucleons and σ mesons on the production of strange particles in neutron stars. Wefind that the stiffer the nuclear matter is, the more easily the strange particles is produced in neutron stars. The vacuum fluctuation of nucleons has large effect on strange particle production while that of σ meson has little effect on it.

  17. Strange star candidates revised within a quark model with chiral mass scaling

    Institute of Scientific and Technical Information of China (English)

    Ang Li; Guang-Xiong Peng; Ju-Fu Lu

    2011-01-01

    We calculate the properties of static strange stars using a quark model with chiral mass scaling. The results are characterized by a large maximum mass (~ 1.6 M⊙) and radius (~ 10 km). Together with a broad collection of modern neutron star models, we discuss some recent astrophysical observational data that could shed new light on the possible presence of strange quark matter in compact stars. We conclude that none of the present astrophysical observations can prove or confute the existence of strange stars.

  18. Fast Radio Bursts from the Collapse of Strange Star Crusts

    Science.gov (United States)

    Zhang, Yue; Geng, Jin-Jun; Huang, Yong-Feng

    2018-05-01

    Fast radio bursts (FRBs) are transient radio sources at cosmological distances. No counterparts in other bands have been observed for non-repeating FRBs. Here we suggest the collapse of strange star (SS) crusts as a possible origin for FRBs. SSs, which are composed of almost equal numbers of u, d, and s quarks, may be encapsulated by a thin crust of normal hadronic matter. When a SS accretes matter from its environment, the crust becomes heavier and heavier. It may finally collapse, leading to the release of a large amount of magnetic energy and plenty of electron/positron pairs on a very short timescale. Electron/positron pairs in the polar cap region of the SS can be accelerated to relativistic velocities, streaming along the magnetic field lines to form a thin shell. FRBs are produced by coherent emission from these electrons when the shell is expanding. Basic characteristics of observed FRBs can be explained in our model.

  19. Effects of strangeness on the mass-radius of neutron stars in MQMC

    International Nuclear Information System (INIS)

    Sahoo, H.S.; Mishra, R.N.; Panda, P.K.; Barik, N.

    2017-01-01

    With the increase of baryon density towards centers of neutron stars, chemical potentials of neutrons become high so that neutrons at Fermi surfaces are changed to hyperons via strangeness non-conserving weak interactions overcoming rest masses of hyperons. In the present attempt we incorporate an additional pair of hidden strange mesons σ∗ and ϕ which couple only to the strange quark and the hyperons of the nuclear matter

  20. Distinguishing Newly Born Strange Stars from Neutron Stars with g-Mode Oscillations

    International Nuclear Information System (INIS)

    Fu Weijie; Wei Haiqing; Liu Yuxin

    2008-01-01

    The gravity-mode (g-mode) eigenfrequencies of newly born strange quark stars (SQSs) and neutron stars (NSs) are studied. It is found that the eigenfrequencies in SQSs are much lower than those in NSs by almost 1 order of magnitude, since the components of a SQS are all extremely relativistic particles while nucleons in a NS are nonrelativistic. We therefore propose that newly born SQSs can be distinguished from the NSs by detecting the eigenfrequencies of the g-mode pulsations of supernovae cores through gravitational radiation by LIGO-class detectors

  1. Strange Quark Stars in Binaries: Formation Rates, Mergers, and Explosive Phenomena

    International Nuclear Information System (INIS)

    Wiktorowicz, G.; Drago, A.; Pagliara, G.; Popov, S. B.

    2017-01-01

    Recently, the possible coexistence of a first family composed of “normal” neutron stars (NSs) with a second family of strange quark stars (QSs) has been proposed as a solution of problems related to the maximum mass and to the minimal radius of these compact stellar objects. In this paper, we study the mass distribution of compact objects formed in binary systems and the relative fractions of quark and NSs in different subpopulations. We incorporate the strange QS formation model provided by the two-families scenario, and we perform a large-scale population synthesis study in order to obtain the population characteristics. According to our results, the main channel for strange QS formation in binary systems is accretion from a secondary companion on an NS. Therefore, a rather large number of strange QSs form by accretion in low-mass X-ray binaries and this opens the possibility of having explosive GRB-like phenomena not related to supernovae and not due to the merger of two NSs. The number of double strange QS systems is rather small, with only a tiny fraction that merge within a Hubble time. This drastically limits the flux of strangelets produced by the merger, which turns out to be compatible with all limits stemming from Earth and lunar experiments. Moreover, this value of the flux rules out at least one relevant channel for the transformation of all NSs into strange QSs by strangelets’ absorption.

  2. Strange Quark Stars in Binaries: Formation Rates, Mergers, and Explosive Phenomena

    Science.gov (United States)

    Wiktorowicz, G.; Drago, A.; Pagliara, G.; Popov, S. B.

    2017-09-01

    Recently, the possible coexistence of a first family composed of “normal” neutron stars (NSs) with a second family of strange quark stars (QSs) has been proposed as a solution of problems related to the maximum mass and to the minimal radius of these compact stellar objects. In this paper, we study the mass distribution of compact objects formed in binary systems and the relative fractions of quark and NSs in different subpopulations. We incorporate the strange QS formation model provided by the two-families scenario, and we perform a large-scale population synthesis study in order to obtain the population characteristics. According to our results, the main channel for strange QS formation in binary systems is accretion from a secondary companion on an NS. Therefore, a rather large number of strange QSs form by accretion in low-mass X-ray binaries and this opens the possibility of having explosive GRB-like phenomena not related to supernovae and not due to the merger of two NSs. The number of double strange QS systems is rather small, with only a tiny fraction that merge within a Hubble time. This drastically limits the flux of strangelets produced by the merger, which turns out to be compatible with all limits stemming from Earth and lunar experiments. Moreover, this value of the flux rules out at least one relevant channel for the transformation of all NSs into strange QSs by strangelets’ absorption.

  3. Strange Quark Stars in Binaries: Formation Rates, Mergers, and Explosive Phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Wiktorowicz, G. [Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warsaw (Poland); Drago, A.; Pagliara, G. [Dipartimento di Fisica e Scienze della Terra dell’Università di Ferrara and INFN Sezione di Ferrara, Via Saragat 1, I-44100 Ferrara (Italy); Popov, S. B., E-mail: gwiktoro@astrouw.edu.pl [Sternberg Astronomical Institute, Lomonosov Moscow State University, Universitetsky prospekt 13, 119234, Moscow (Russian Federation)

    2017-09-10

    Recently, the possible coexistence of a first family composed of “normal” neutron stars (NSs) with a second family of strange quark stars (QSs) has been proposed as a solution of problems related to the maximum mass and to the minimal radius of these compact stellar objects. In this paper, we study the mass distribution of compact objects formed in binary systems and the relative fractions of quark and NSs in different subpopulations. We incorporate the strange QS formation model provided by the two-families scenario, and we perform a large-scale population synthesis study in order to obtain the population characteristics. According to our results, the main channel for strange QS formation in binary systems is accretion from a secondary companion on an NS. Therefore, a rather large number of strange QSs form by accretion in low-mass X-ray binaries and this opens the possibility of having explosive GRB-like phenomena not related to supernovae and not due to the merger of two NSs. The number of double strange QS systems is rather small, with only a tiny fraction that merge within a Hubble time. This drastically limits the flux of strangelets produced by the merger, which turns out to be compatible with all limits stemming from Earth and lunar experiments. Moreover, this value of the flux rules out at least one relevant channel for the transformation of all NSs into strange QSs by strangelets’ absorption.

  4. The effect of dynamical quark mass on the calculation of a strange quark star's structure

    Institute of Scientific and Technical Information of China (English)

    Gholam Hossein Bordbar; Babak Ziaei

    2012-01-01

    We discuss the dynamical behavior of strange quark matter components,in particular the effects of density dependent quark mass on the equation of state of strange quark matter.The dynamical masses of quarks are computed within the Nambu-Jona-Lasinio model,then we perform strange quark matter calculations employing the MIT bag model with these dynamical masses.For the sake of comparing dynamical mass interaction with QCD quark-quark interaction,we consider the one-gluon-exchange term as the effective interaction between quarks for the MIT bag model.Our dynamical approach illustrates an improvement in the obtained equation of state values.We also investigate the structure of the strange quark star using TolmanOppenheimer-Volkoff equations for all applied models.Our results show that dynamical mass interaction leads to lower values for gravitational mass.

  5. A class of exact strange quark star model

    Indian Academy of Sciences (India)

    1Department of Mathematics; 2Department of Physics, Eastern University,. Chenkalady, Sri ... true ground state of nuclear matter [8] and occupies the entire compact star. These highly ... Neutron stars with 1.5–1.8M⊙ masses having ... origin of the pressure anisotropy, the role of pressure anisotropy in modelling compact.

  6. Strangeness in nuclei and neutron stars: a challenging puzzle

    Directory of Open Access Journals (Sweden)

    Lonardoni Diego

    2016-01-01

    Full Text Available The prediction of neutron stars properties is strictly connected to the employed nuclear interactions. The appearance of hyperons in the inner core of the star is strongly dependent on the details of the underlying hypernuclear force. We summarize our recent quantum Monte Carlo results on the development of realistic two- and threebody hyperon-nucleon interactions based on the available experimental data for light- and medium-heavy hypernuclei.

  7. Imprint of the symmetry energy on the inner crust and strangeness content of neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Providencia, Constanca; Chiacchiera, Silvia; Grill, Fabrizio; Rabhi, Aziz; Vidana, Isaac [University of Coimbra, Centro de Fisica Computacional, Department of Physics, Coimbra (Portugal); Avancini, Sidney S.; Menezes, Debora P. [Universidade Federal de Santa Catarina, Departamento de Fisica, SC - CP. 476, Florianopolis (Brazil); Cavagnoli, Rafael [Universidade Federal de Pelotas, Departamento de Fisica, CP 354, Pelotas/SC (Brazil); Ducoin, Camille; Margueron, Jerome [Universite Claude Bernard Lyon 1, Institut de Physique Nucleaire de Lyon, Villeurbanne (France)

    2014-02-15

    In this work we study the effect of the symmetry energy on several properties of neutron stars. First, we discuss its effect on the density, proton fraction and pressure of the neutron star crust-core transition. We show that whereas the first two quantities present a clear correlation with the slope parameter L of the symmetry energy, no satisfactory correlation is seen between the transition pressure and L. However, a linear combination of the slope and curvature parameters at ρ = 0.1 fm{sup -3} is well correlated with the transition pressure. In the second part we analyze the effect of the symmetry energy on the pasta phase. It is shown that the size of the pasta clusters, number of nucleons and the cluster proton fraction depend on the density dependence of the symmetry energy: a small L gives rise to larger clusters. The influence of the equation of state at subsaturation densities on the extension of the inner crust of the neutron star is also discussed. Finally, the effect of the density dependence of the symmetry energy on the strangeness content of neutron stars is studied in the last part of the work. It is found that charged (neutral) hyperons appear at smaller (larger) densities for smaller values of the slope parameter L. A linear correlation between the radius and the strangeness content of a star with a fixed mass is also found. (orig.)

  8. Anisotropic strange stars under simplest minimal matter-geometry coupling in the f (R ,T ) gravity

    Science.gov (United States)

    Deb, Debabrata; Guha, B. K.; Rahaman, Farook; Ray, Saibal

    2018-04-01

    We study strange stars in the framework of f (R ,T ) theory of gravity. To provide exact solutions of the field equations it is considered that the gravitational Lagrangian can be expressed as the linear function of the Ricci scalar R and the trace of the stress-energy tensor T , i.e. f (R ,T )=R +2 χ T , where χ is a constant. We also consider that the strange quark matter (SQM) distribution inside the stellar system is governed by the phenomenological MIT bag model equation of state (EOS), given as pr=1/3 (ρ -4 B ) , where B is the bag constant. Further, for a specific value of B and observed values of mass of the strange star candidates we obtain the exact solution of the modified Tolman-Oppenheimer-Volkoff (TOV) equation in the framework of f (R ,T ) gravity and have studied in detail the dependence of the different physical parameters, like the metric potentials, energy density, radial and tangential pressures and anisotropy etc., due to the chosen different values of χ . Likewise in GR, as have been shown in our previous work [Deb et al., Ann. Phys. (Amsterdam) 387, 239 (2017), 10.1016/j.aop.2017.10.010] in the present work also we find maximum anisotropy at the surface which seems an inherent property of the strange stars in modified f (R ,T ) theory of gravity. To check the physical acceptability and stability of the stellar system based on the obtained solutions we have performed different physical tests, viz., the energy conditions, Herrera cracking concept, adiabatic index etc. In this work, we also have explained the effects, those are arising due to the interaction between the matter and the curvature terms in f (R ,T ) gravity, on the anisotropic compact stellar system. It is interesting to note that as the values of χ increase the strange stars become more massive and their radius increase gradually so that eventually they gradually turn into less dense compact objects. The present study reveals that the modified f (R ,T ) gravity is a suitable

  9. Strange bedfellows: The curious case of STAR and Moata

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.M., E-mail: ams@ansto.gov.au [Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC NSW 2232 (Australia); Levchenko, V.A.; Malone, G. [Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC NSW 2232 (Australia)

    2013-01-15

    The 2 MV tandem accelerator named 'STAR' was installed at ANSTO in 2003 and commissioned in 2004. It is used for ion beam analysis (IBA) and for radiocarbon measurements by accelerator mass spectrometry (AMS). Convenient space for the accelerator was found in the same building occupied by the decommissioned Argonaut-class nuclear reactor 'Moata'; the name derives from the aboriginal word for 'fire stick' or 'gentle fire', appropriate for a 100 kW research reactor. This reactor operated between 1961 and 1995. In 2007 ANSTO's Engineering Division assembled a team to dismantle and remove the reactor structure, along with its 12.1 tonnes of graphite reflector. The removal and remediation was completed in November 2010 and has won the team a number of prestigious awards. The entire operation was conducted inside a negatively-pressurised double-walled vinyl tent. An air curtain was positioned around the reactor core. The exhaust air from the tent passed through 2-stage HEPA filters before venting through an external stack. Neither ANSTO staff nor contractors received any significant radiation dose during the operation. Given the sensitivity of STAR for detection of {sup 14}C/{sup 12}C ({approx}10{sup -16}) and the numerous routes for production of {sup 14}C in the reactor such as {sup 13}C(n, {gamma}){sup 14}C, {sup 14}N(n, p){sup 14}C and {sup 17}O(n, {alpha}){sup 14}C there was the potential to directly contaminate the STAR environment with {sup 14}C. Furthermore, there was concern that reactor-{sup 14}C could find its way from this building into the building where the radiocarbon sample preparation laboratories are located. This necessitated restrictions on staff movement between the buildings. We report on {sup 14}C control measurements made during and after the operation. These involved direct measurements on the reactor graphite and concrete bioshield, blank targets that were exposed in the building, swipe samples taken

  10. Strange bedfellows: The curious case of STAR and Moata

    Science.gov (United States)

    Smith, A. M.; Levchenko, V. A.; Malone, G.

    2013-01-01

    The 2 MV tandem accelerator named ‘STAR’ was installed at ANSTO in 2003 and commissioned in 2004. It is used for ion beam analysis (IBA) and for radiocarbon measurements by accelerator mass spectrometry (AMS). Convenient space for the accelerator was found in the same building occupied by the decommissioned Argonaut-class nuclear reactor ‘Moata’; the name derives from the aboriginal word for ‘fire stick’ or ‘gentle fire’, appropriate for a 100 kW research reactor. This reactor operated between 1961 and 1995. In 2007 ANSTO’s Engineering Division assembled a team to dismantle and remove the reactor structure, along with its 12.1 tonnes of graphite reflector. The removal and remediation was completed in November 2010 and has won the team a number of prestigious awards. The entire operation was conducted inside a negatively-pressurised double-walled vinyl tent. An air curtain was positioned around the reactor core. The exhaust air from the tent passed through 2-stage HEPA filters before venting through an external stack. Neither ANSTO staff nor contractors received any significant radiation dose during the operation. Given the sensitivity of STAR for detection of 14C/12C (∼10-16) and the numerous routes for production of 14C in the reactor such as 13C(n, γ)14C, 14N(n, p)14C and 17O(n, α)14C there was the potential to directly contaminate the STAR environment with 14C. Furthermore, there was concern that reactor-14C could find its way from this building into the building where the radiocarbon sample preparation laboratories are located. This necessitated restrictions on staff movement between the buildings. We report on 14C control measurements made during and after the operation. These involved direct measurements on the reactor graphite and concrete bioshield, blank targets that were exposed in the building, swipe samples taken inside the tent and around the building and aerosol samples that were collected inside the building throughout the

  11. RX J1856.5-3754: A Strange Star with Solid Quark Surface?

    Science.gov (United States)

    Zhang, Xiaoling; Xu, Renxin; Zhang, Shuangnan

    2003-01-01

    The featureless spectra of isolated 'neutron stars' may indicate that they are actually bare strange stars but a definitive conclusion on the nature of the compact objects cannot be reached until accurate and theoretically calculated spectra of the bare quark surface are known. However due to the complex nonlinearity of quantum chromodynamics it is almost impossible to present a definitive and accurate calculation of the density-dominated quark-gluon plasma from the first principles. Nevertheless it was suggested that cold quark matter with extremely high baryon density could be in a solid state. Within the realms of this possibility we have fitted the 500ks Chandra LETG/HRC data for the brightest isolated neutron star RX 51856.5-3754 with a phenomenological spectral model and found that electric conductivity of quark matter on the stellar surface is about 1.5 x 10(exp 16)/s.

  12. Radial oscillations of strange quark stars admixed with condensed dark matter

    Science.gov (United States)

    Panotopoulos, G.; Lopes, Ilídio

    2017-10-01

    We compute the 20 lowest frequency radial oscillation modes of strange stars admixed with condensed dark matter. We assume a self-interacting bosonic dark matter, and we model dark matter inside the star as a Bose-Einstein condensate. In this case the equation of state is a polytropic one with index 1 +1 /n =2 and a constant K that is computed in terms of the mass of the dark matter particle and the scattering length. Assuming a mass and a scattering length compatible with current observational bounds for self-interacting dark matter, we have integrated numerically first the Tolman-Oppenheimer-Volkoff equations for the hydrostatic equilibrium, and then the equations for the perturbations ξ =Δ r /r and η =Δ P /P . For a compact object with certain mass and radius we have considered here three cases, namely no dark matter at all and two different dark matter scenarios. Our results show that (i) the separation between consecutive modes increases with the amount of dark matter, and (ii) the effect is more pronounced for higher order modes. These effects are relevant even for a strange star made of 5% dark matter.

  13. Ultra-dense neutron star matter, strange quark stars, and the nuclear equation of state

    International Nuclear Information System (INIS)

    Weber, F.; Meixner, M.; Negreiros, R.P.; Malheiro, M.

    2007-01-01

    With central densities way above the density of atomic nuclei, neutron stars contain matter in one of the densest forms found in the universe. Depending of the density reached in the cores of neutron stars, they may contain stable phases of exotic matter found nowhere else in space. This article gives a brief overview of the phases of ultra-dense matter predicted to exist deep inside neutron stars and discusses the equation of state (EoS) associated with such matter. (author)

  14. A STRANGE STAR SCENARIO FOR THE FORMATION OF ECCENTRIC MILLISECOND PULSAR/HELIUM WHITE DWARF BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Long; Li, Xiang-Dong [Department of Astronomy, Nanjing University, Nanjing 210046 (China); Dey, Jishnu; Dey, Mira, E-mail: lixd@nju.edu.cn [Department of Physics, Presidency University, 86/1, College Street, Kolkata 700 073 (India)

    2015-07-01

    According to the recycling scenario, millisecond pulsars (MSPs) have evolved from low-mass X-ray binaries (LMXBs). Their orbits are expected to be circular due to tidal interactions during binary evolution, as observed in most binary MSPs. There are some peculiar systems that do not fit this picture. Three recent examples are the PSRs J2234+06, J1946+3417, and J1950+2414, all of which are MSPs in eccentric orbits but with mass functions compatible with expected He white dwarf (WD) companions. It has been suggested these MSPs may have formed from delayed accretion-induced collapse of massive WDs, or the eccentricity may be induced by dynamical interaction between the binary and a circumbinary disk. Assuming that the core density of accreting neutron stars (NSs) in LMXBs may reach the density of quark deconfinement, which can lead to phase transition from NSs to strange quark stars, we show that the resultant MSPs are likely to have an eccentric orbit, due to the sudden loss of the gravitational mass of the NS during the transition. The eccentricities can be reproduced with a reasonable estimate of the mass loss. This scenario might also account for the formation of the youngest known X-ray binary Cir X–1, which also possesses a low-field compact star in an eccentric orbit.

  15. Reconstruction and study of the multi-strange baryons in ultra-relativistic heavy ion collisions at a center-of-mass energy of 200 GeV, with the Star experiment at RHIC

    International Nuclear Information System (INIS)

    Faivre, J.

    2004-10-01

    The study of strangeness production is essential for the understanding of processes occurring in ultra-relativistic heavy ion collisions. Strangeness production is directly linked to the phase of deconfined partons that followed these collisions: the quark and gluon plasma. STAR, one of the 4 experiments at RHIC collider, is a perfect tool for studying the multi-strange Ξ and Ω particles. We have devised a Ξ and Ω reconstruction program using signals from the STAR time projection chamber. We have worked out a multi-variable selection method for extracting the signals from the combinative background: the linear discriminant analysis. We have applied it to Au-Au collisions at 200 GeV (in the center of mass frame) to improve the accuracy of previous results. The Ω and anti-Ω production rates have been obtained for 3 ranges of centrality as well as their radial flow and their kinetic uncoupling temperatures. The gain on the relative uncertainty is between 15 and 30% according to the variable. The average speed of the radial flow is 0.50 ± 0.02 and the kinetic uncoupling temperature is 132 ± 20 MeV which indicates that multi-strange baryons uncouple in hadronic medium earlier that lighter particles like pions, kaons and protons. However, uncertainty intervals remain too broad to draw strong conclusions. (A.C.)

  16. On the short periods oscillation in relativistic stars

    International Nuclear Information System (INIS)

    Aquilano, R.; Morales, S.; Navone, H.; Sevilla, D.; Zorzi, A.

    2009-01-01

    We expand the study of neutron and strange matter stars with general relativistic formalism. We analyze the correlation with the observational data short periods oscillations in these stars, and we intend to discriminate between them.

  17. Orbital and epicyclic frequencies around neutron and strange stars in R{sup 2} gravity

    Energy Technology Data Exchange (ETDEWEB)

    Staykov, Kalin V., E-mail: kstaykov@phys.uni-sofia.bg [Department of Theoretical Physics, Faculty of Physics, Sofia University, 1164, Sofia (Bulgaria); Doneva, Daniela D., E-mail: daniela.doneva@uni-tuebingen.de [Theoretical Astrophysics, Eberhard Karls University of Tübingen, 72076, Tübingen (Germany); INRNE-Bulgarian Academy of Sciences, 1784, Sofia (Bulgaria); Yazadjiev, Stoytcho S., E-mail: yazad@phys.uni-sofia.bg [Department of Theoretical Physics, Faculty of Physics, Sofia University, 1164, Sofia (Bulgaria); Theoretical Astrophysics, Eberhard Karls University of Tübingen, 72076, Tübingen (Germany)

    2015-12-21

    According to various models, the orbital and the epicyclic frequencies of particles moving on a circular orbit around compact objects are related to the quasi-periodic oscillations observed in the X-ray flux of some pulsars or black hole candidates. It is expected that they originate from the inner edge of the accretion discs, deep into the gravitational field of the compact objects. Considering the planned new generation X-ray timing observatories with large collective areas, the quasi-periodic oscillations might be an excellent tool for testing gravity in strong field regime and, respectively, alternative gravitational theories. We examine the orbital and the epicyclic frequencies of a particle moving on a circular orbit around neutron or strange stars in R{sup 2} gravity. The case of slow rotation is considered too. The R{sup 2} gravity results are compared to the general relativistic case. We comment on the deviations from general relativity, as well as the deviations due to rotation in both theories.

  18. Orbital and epicyclic frequencies around neutron and strange stars in R{sup 2} gravity

    Energy Technology Data Exchange (ETDEWEB)

    Staykov, Kalin V. [Sofia University, Department of Theoretical Physics, Faculty of Physics, Sofia (Bulgaria); Doneva, Daniela D. [Eberhard Karls University of Tuebingen, Theoretical Astrophysics, Tuebingen (Germany); INRNE-Bulgarian Academy of Sciences, Sofia (Bulgaria); Yazadjiev, Stoytcho S. [Sofia University, Department of Theoretical Physics, Faculty of Physics, Sofia (Bulgaria); Eberhard Karls University of Tuebingen, Theoretical Astrophysics, Tuebingen (Germany)

    2015-12-15

    According to various models, the orbital and the epicyclic frequencies of particles moving on a circular orbit around compact objects are related to the quasi-periodic oscillations observed in the X-ray flux of some pulsars or black hole candidates. It is expected that they originate from the inner edge of the accretion discs, deep into the gravitational field of the compact objects. Considering the planned new generation X-ray timing observatories with large collective areas, the quasi-periodic oscillations might be an excellent tool for testing gravity in strong field regime and, respectively, alternative gravitational theories. We examine the orbital and the epicyclic frequencies of a particle moving on a circular orbit around neutron or strange stars in R{sup 2} gravity. The case of slow rotation is considered too. The R{sup 2} gravity results are compared to the general relativistic case. We comment on the deviations from general relativity, as well as the deviations due to rotation in both theories. (orig.)

  19. Moment of inertia, quadrupole moment, Love number of neutron star and their relations with strange-matter equations of state

    Science.gov (United States)

    Bandyopadhyay, Debades; Bhat, Sajad A.; Char, Prasanta; Chatterjee, Debarati

    2018-02-01

    We investigate the impact of strange-matter equations of state involving Λ hyperons, Bose-Einstein condensate of K- mesons and first-order hadron-quark phase transition on moment of inertia, quadrupole moment and tidal deformability parameter of slowly rotating neutron stars. All these equations of state are compatible with the 2 M_{solar} constraint. The main findings of this investigation are the universality of the I- Q and I -Love number relations, which are preserved by the EoSs including Λ hyperons and antikaon condensates, but broken in the presence of a first-order hadron-quark phase transition. Furthermore, it is also noted that the quadrupole moment approaches the Kerr value of a black hole for maximum-mass neutron stars.

  20. Search for (exotic) strange matter in the Star and Alice experiments with the ultra-relativistic heavy ion colliders RHIC and LHC

    International Nuclear Information System (INIS)

    Vernet, R.

    2006-02-01

    Ultra-relativistic heavy ion collisions offer the possibility to create conditions of temperature and density that could lead nuclear matter to a state of deconfined partons, the quark-gluon plasma. Strange baryon production is one of the essential observables to understand the mechanisms involved in the medium. Furthermore, theories predict a possible production of strange dibaryons, still hypothetical particles, from which one could draw important inferences in nuclear physics and astrophysics. The experiments STAR at RHIC, and, soon, ALICE at LHC, allow one to search for strange baryons and dibaryons. The STAR sensitivity to the metastable dibaryon H 0 in the Λpπ - decay mode was calculated thanks to a dedicated simulation. The search for the H 0 , and for the Ξ - p resonance as well, was performed in the STAR Au+Au data at √(s NN ) = 62.4 and 200 GeV energies. Within the framework of the preparation of ALICE to the first Pb+Pb data, the detector ability to identify strange baryons Λ, Ξ and Ω, was estimated via several simulations. So as to favour the reconstruction efficiency in a large range of transverse momentum while keeping a reasonable S/B ratio, the influence of the geometrical selections and the size of the reconstruction zone was emphasized. The ALICE sensitivities to the metastable strange dibaryons H 0 and (Ξ 0 p) b and to the ΛΛ resonance were calculated as well. (author)

  1. Calculation of the structural properties of a strange quark star in the presence of a strong magnetic field using a density dependent bag constant

    Institute of Scientific and Technical Information of China (English)

    Gholam Hossein Bordbar; Hajar Bahri; Fatemeh Kayanikhoo

    2012-01-01

    We have calculated the structural properties of a strange quark star with a static model in the presence of a strong magnetic field.To this end,we use the MITbag model with a density dependent bag constant.To parameterize the density dependence of the bag constant,we have used our results for the lowest order constrained variational calculation of the asymmetric nuclear matter.By calculating the equation of state of strange quark matter,we have shown that the pressure of this system increases by increasing both density and magnetic field.Finally,we have investigated the effect of density dependence of the bag constant on the structural properties of a strange quark star.

  2. Massive neutron star with strangeness in a relativistic mean-field model with a high-density cutoff

    Science.gov (United States)

    Zhang, Ying; Hu, Jinniu; Liu, Peng

    2018-01-01

    The properties of neutron stars with the strangeness degree of freedom are studied in the relativistic mean-field (RMF) model via including a logarithmic interaction as a function of the scalar meson field. This interaction, named the σ -cut potential, can largely reduce the attractive contributions of the scalar meson field at high density without any influence on the properties of nuclear structure around the normal saturation density. In this work, the TM1 parameter set is chosen as the RMF interaction, while the strengths of σ -cut potential are constrained by the properties of finite nuclei so that we can obtain a reasonable effective nucleon-nucleon interaction. The hyperons Λ ,Σ , and Ξ are considered in neutron stars within this framework, whose coupling constants with mesons are determined by the latest hyperon-nucleon and Λ -Λ potentials extracted from the available experimental data of hypernuclei. The maximum mass of neutron star can be larger than 2 M⊙ with these hyperons in the present framework. Furthermore, the nucleon mass at high density will be saturated due to this additional σ -cut potential, which is consistent with the conclusions obtained by other calculations such as Brueckner-Hartree-Fock theory and quark mean-field model.

  3. THE NEWLY BORN MAGNETARS POWERING GAMMA-RAY BURST INTERNAL-PLATEAU EMISSION: ARE THERE STRANGE STARS?

    International Nuclear Information System (INIS)

    Yu Yunwei; Cao Xiaofeng; Zheng Xiaoping

    2009-01-01

    The internal-plateau X-ray emission of gamma-ray bursts (GRBs) indicates that a newly born magnetar could be the central object of some GRBs. The observed luminosity and duration of the plateaus suggest that, for such a magnetar, a rapid spin with a sub- or millisecond period is sometimes able to last thousands of seconds. In this case, the conventional neutron star (NS) model for the magnetar may be challenged, since the rapid spin of nascent NSs would be remarkably decelerated within hundreds of seconds due to r-mode instability. In contrast, the r-modes can be effectively suppressed in nascent strange stars (SSs). In other words, to a certain extent, only SSs can keep nearly constant extremely rapid spin for a long period of time during the early ages of the stars. We thus propose that the sample of the GRB rapidly spinning magnetars can be used to test the SS hypothesis based on the distinct spin limits of NSs and SSs.

  4. The Elliptic Flow of Multi-Strange Hadrons in √SNN=200GeV Au + Au Collisions at STAR%The Elliptic Flow of Multi-Strange Hadrons in √SNN=200GeV Au + Au Collisions at STAR

    Institute of Scientific and Technical Information of China (English)

    张小平

    2012-01-01

    Azimuthal anisotropy, especially for the multi-strange hadrons, is expected to be sensitive to the dynamical evolution in the early stage of high energy nuclear collisions. In this paper we present the latest results of multi-strange hadron elliptic flow in Au + Au collisions at √SNN=200GeV from the STAR experiment at RHIC. The number-of-quark scaling is evidenced with φ(ss) and Ω(sss) with highly statistical data, which shows strange quark collectivity at RHIC. The u2 of φ meson is found to be consistent with that of proton within statistical error bars at pw 〈 1 GeV/c.

  5. Strange Dibaryons

    International Nuclear Information System (INIS)

    Franklin, G.B.; Athanas, M.; Barnes, P.D.

    1993-01-01

    Strange Dibaryons, six valence-quark hadrons constructed from one or more strange quarks, are predicted to have greater binding than dibaryons in the non-strange sector. The flavor-singlet dibaryon with quark structure ''uuddss'' is of particular theoretical and experimental interest. A brief review of the status of H dibaryon studies is presented with emphasis on experiment E813 currently taking data at the AGS

  6. Strange particles

    International Nuclear Information System (INIS)

    Chinowsky, W.

    1989-01-01

    Work done in the mid 1950s at Brookhaven National Laboratory on strange particles is described. Experiments were done on the Cosmotron. The author describes his own and others' work on neutral kaons, lambda and theta particles and points out the theoretical gap between predictions and experimental findings. By the end of the decade, the theory of strange particles was better understood. (UK)

  7. Characterisation of a dense state of quarks and gluons by the multi-strange hyperons excitation functions as measured with the Star experiment at RHIC

    International Nuclear Information System (INIS)

    Speltz, J.

    2006-10-01

    In this work, we characterize the production of the multi-strange baryons Xi and Omega in Au+Au collisions at RHIC, where the possible formation of a matter of deconfined quarks and gluons (QGP) is expected. We analyze with the STAR experiment, the collisions obtained at an energy of 62 GeV, intermediate between the one reached at the SPS (17 GeV) and the nominal energy of RHIC (200 GeV). Transverse momentum spectra, yields and elliptic flow are measured with different methods allowing for a relevant estimation of systematic errors. The results are compared to statistical and hydrodynamic models that we have adapted for their use at 62 GeV. The so obtained chemical and dynamic properties of the created medium indicate the formation of a thermalized, at least partially, medium and suggests the formation of a comparable matter at 62 GeV and at 200 GeV. (author)

  8. Strange Assemblage

    Directory of Open Access Journals (Sweden)

    David Robert Cole

    2014-08-01

    Full Text Available This paper contends that the power of Deleuze & Guattari’s (1988 notion of assemblage as theorised in 1000 Plateaus can be normalised and reductive with reference to its application to any social-cultural context where an open system of dynamic and fluid elements are located. Rather than determining the assemblage in this way, this paper argues for an alternative conception of ‘strange assemblage’ that must be deliberately and consciously created through rigorous and focused intellectual, creative and philosophical work around what makes assemblages singular. The paper will proceed with examples of ‘strange assemblage’ taken from a film by Peter Greenaway (A Zed and 2 Noughts; the film ‘Performance’; educational research with Sudanese families in Australia; the book, Bomb Culture by Jeff Nuttall (1970; and the band Hawkwind. Fittingly, these elements are themselves chosen to demonstrate the concept of ‘strange assemblage’, and how it can be presented. How exactly the elements of a ‘strange assemblage’ come together and work in the world is unknown until they are specifically elaborated and created ‘in the moment’. Such spontaneous methodology reminds us of the 1960s ‘Happenings’, the Situationist International and Dada/Surrealism. The difference that will be opened up by this paper is that all elements of this ‘strange assemblage’ cohere in terms of a rendering of ‘the unacceptable.'

  9. Study of stellar objects with strange quark matter crust

    International Nuclear Information System (INIS)

    Hothi, N.; Bisht, S.

    2012-01-01

    The absolute stability of strange quark matter is a viable possibility and immensely effects physics at the astrophysical scale. Relativistic heavy-ion reactions offer a stage to produce this exotic state of matter and the enhanced production of strange particles during these reactions can be studied within the framework of quark-gluon plasma (QGP). We have tried to investigate the role of strangeness under the compact star phenomenology. Emphasis is laid upon the possibility of existence of a third family of strange quark stars and its study help in revealing a number of unexplored features of the cosmos. Bag model parameters have been used to determine some integral parameters for a sequence of strange stars with crust and strange dwarfs constructed out of strange quark matter crust. A comparative analysis is performed between the strange and neutron stars and the strange and white dwarfs based upon these intrinsic parameters and paramount differences are observed. The intimacy between astrophysics and strange quarks depends strongly upon the strange quark matter hypothesis. It states that for a collection of more than a few hundred u, d and s quarks, the energy per baryon E/A of strange quark matter (SQM) can be well below the energy per baryon of the most stable atomic nuclei

  10. Flipped neutrino emissivity from strange matter

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, A.; Dutta, S. (Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India))

    1994-04-15

    Energy loss due to wrong helicity sterile neutrinos through spin flip processes leads to rapid cooling of nascent neutron stars. The observed cooling of neutron stars associated with SN 1987A seems to preclude the existence of Dirac neutrinos with a mass in excess of 20 keV. Assuming that nuclear matter in the core of the neutron star undergoes a phase transition to quark matter leading to a strange star or a neutron star with a strange matter core, we examine the emission of flipped Dirac neutrinos for two dominant processes: quark-neutrino scattering [[ital q]+[nu][sub [minus

  11. Quark Condensate in the Strange Matter

    Institute of Scientific and Technical Information of China (English)

    LU Chang-Fang; LU" Xiao-Fu

    2003-01-01

    In a nonlinear chiral SU(3) framework, we investigate the quark condensate in the strange matter including N, Σ, Ξ, and Λ, making use of chiral symmetry spontaneous breaking Lagrangian and mean-field approximation. The results show that the chiral symmetry is restored partially when the strange matter density increases and that 〈π→2〉 plays a very important role in the strange matter which may approach the constituents of the neutron stars. In addition, we can find that the strange matter density where the π-condensate emerges leads to the ratio of the nucleon number to baryon number.

  12. Translation and discriminative validation of the STarT Back Screening Tool into Danish.

    Science.gov (United States)

    Morsø, Lars; Albert, Hanne; Kent, Peter; Manniche, Claus; Hill, Jonathan

    2011-12-01

    The STarT Back Screening Tool (STarT) is a nine-item patient self-report questionnaire that classifies low back pain patients into low, medium or high risk of poor prognosis. When assessed by GPs, these subgroups can be used to triage patients into different evidence-based treatment pathways. The objective of this study was to translate the English version of STarT into Danish (STarT-dk) and test its discriminative validity. Translation was performed using methods recommended by best practice translation guidelines. Psychometric validation of the discriminative ability was performed using the Area Under the Curve statistic. The Area Under the Curve was calculated for seven of the nine items where reference standards were available and compared with the original English version. The linguistic translation required minor semantic and layout alterations. The response options were changed from "agree/disagree" to "yes/no" for four items. No patients reported item ambiguity using the final version. The Area Under the Curve ranged from 0.735 to 0.855 (CI95% 0.678-0.897) in a Danish cohort (n = 311) and 0.840 to 0.925 (CI95% 0.772-0.948) in the original English cohort (n = 500). On four items, the Area Under the Curve was statistically similar between the two cohorts but lower on three psychosocial sub-score items. The translation was linguistically accurate and the discriminative validity broadly similar, with some differences probably due to differences in severity between the cohorts and the Danish reference standard questionnaires not having been validated. Despite those differences, we believe the results show that the STarT-dk has sufficient patient acceptability and discriminative validity to be used in Denmark.

  13. Strangeness photoproduction

    International Nuclear Information System (INIS)

    Berthot, J.; Saghai, B.

    1989-01-01

    A non exhaustive review, about the strangeness photo-production is presented here in relation with the new electrons machines. Accent is put on the elementary reaction γp → K + Λ. The experiments on electroproduction and the study of hypernuclei with the electromagnetic probe are also discussed [fr

  14. Strange Men

    OpenAIRE

    Snider, William Stephen

    2017-01-01

    Haamid lives a modest life running a restaurant in a small market town in Uganda. A member of the minority Indian population, he is estranged from his family for reasons he prefers not to discuss. At night he cooks elaborate dinners that he eats alone. When an openly gay Peace Corps volunteer comes to town looking for more than a good meal, Haamid's comfortable routine is broken, and his life is put in danger. STRANGE MEN explores the limits of good intentions and the uneven stakes for Americ...

  15. Search for (exotic) strange matter in the Star and Alice experiments with the ultra-relativistic heavy ion colliders RHIC and LHC; Recherche de matiere etrange (exotique) dans les experiences STAR et ALICE aupres des collisionneurs d'ions lourds ultra-relativistes RHIC et LHC

    Energy Technology Data Exchange (ETDEWEB)

    Vernet, R

    2006-02-15

    Ultra-relativistic heavy ion collisions offer the possibility to create conditions of temperature and density that could lead nuclear matter to a state of deconfined partons, the quark-gluon plasma. Strange baryon production is one of the essential observables to understand the mechanisms involved in the medium. Furthermore, theories predict a possible production of strange dibaryons, still hypothetical particles, from which one could draw important inferences in nuclear physics and astrophysics. The experiments STAR at RHIC, and, soon, ALICE at LHC, allow one to search for strange baryons and dibaryons. The STAR sensitivity to the metastable dibaryon H{sup 0} in the {lambda}p{pi}{sup -} decay mode was calculated thanks to a dedicated simulation. The search for the H{sup 0}, and for the {xi}{sup -}p resonance as well, was performed in the STAR Au+Au data at {radical}(s{sub NN}) = 62.4 and 200 GeV energies. Within the framework of the preparation of ALICE to the first Pb+Pb data, the detector ability to identify strange baryons {lambda}, {xi} and {omega}, was estimated via several simulations. So as to favour the reconstruction efficiency in a large range of transverse momentum while keeping a reasonable S/B ratio, the influence of the geometrical selections and the size of the reconstruction zone was emphasized. The ALICE sensitivities to the metastable strange dibaryons H{sup 0} and ({xi}{sup 0}p){sub b} and to the {lambda}{lambda} resonance were calculated as well. (author)

  16. Strangeon and Strangeon Star

    Science.gov (United States)

    Xiaoyu, Lai; Renxin, Xu

    2017-06-01

    The nature of pulsar-like compact stars is essentially a central question of the fundamental strong interaction (explained in quantum chromo-dynamics) at low energy scale, the solution of which still remains a challenge though tremendous efforts have been tried. This kind of compact objects could actually be strange quark stars if strange quark matter in bulk may constitute the true ground state of the strong-interaction matter rather than 56Fe (the so-called Witten’s conjecture). From astrophysical points of view, however, it is proposed that strange cluster matter could be absolutely stable and thus those compact stars could be strange cluster stars in fact. This proposal could be regarded as a general Witten’s conjecture: strange matter in bulk could be absolutely stable, in which quarks are either free (for strange quark matter) or localized (for strange cluster matter). Strange cluster with three-light-flavor symmetry is renamed strangeon, being coined by combining “strange nucleon” for the sake of simplicity. A strangeon star can then be thought as a 3-flavored gigantic nucleus, and strangeons are its constituent as an analogy of nucleons which are the constituent of a normal (micro) nucleus. The observational consequences of strangeon stars show that different manifestations of pulsarlike compact stars could be understood in the regime of strangeon stars, and we are expecting more evidence for strangeon star by advanced facilities (e.g., FAST, SKA, and eXTP).

  17. Flipped neutrino emissivity from strange matter

    International Nuclear Information System (INIS)

    Goyal, A.; Dutta, S.

    1994-01-01

    Energy loss due to wrong helicity sterile neutrinos through spin flip processes leads to rapid cooling of nascent neutron stars. The observed cooling of neutron stars associated with SN 1987A seems to preclude the existence of Dirac neutrinos with a mass in excess of 20 keV. Assuming that nuclear matter in the core of the neutron star undergoes a phase transition to quark matter leading to a strange star or a neutron star with a strange matter core, we examine the emission of flipped Dirac neutrinos for two dominant processes: quark-neutrino scattering [q+ν - (bar ν + )→q+ν + (bar ν - )] and the quark neutrino pair bremsstrahlung process [q+q→q+q+ν - bar ν - (ν+bar ν + )]. We determine the composition of quark matter just after core bounce and examine the effect of neutrino degeneracy on the emission rate and mean free path of the wrong helicity neutrinos

  18. Strange quarks in nuclei

    International Nuclear Information System (INIS)

    Dover, C.B.

    1991-06-01

    We survey the field of strange particle nuclear physics, starting with the spectroscopy of strangeness S = -1 Λ hypernuclei, proceeding to an interpretation of recent data on S = -2 ΛΛ hypernuclear production and decay, and finishing with some speculations on the production of multi-strange nuclear composites (hypernuclei or ''strangelets'') in relativistic heavy ion collisions. 41 refs., 5 figs

  19. Relativistic simulations of compact object mergers for nucleonic matter and strange quark matter

    Energy Technology Data Exchange (ETDEWEB)

    Bauswein, Andreas Ottmar

    2010-01-29

    Under the assumption that the energy of the ground state of 3-flavor quark matter is lower than the one of nucleonic matter, the compact stellar remnants of supernova explosions are composed of this quark matter. Because of the appearance of strange quarks, such objects are called strange stars. Considering their observational features, strange stars are very similar to neutron stars made of nucleonic matter, and therefore observations cannot exclude the existence of strange stars. This thesis introduces a new method for simulating mergers of compact stars and black holes within a general relativistic framework. The main goal of the present work is the investigation of the question, whether the coalescence of two strange stars in a binary system yields observational signatures that allow one to distinguish them from colliding neutron stars. In this context the gravitational-wave signals are analyzed. It is found that in general the characteristic frequencies in the gravitational-wave spectra are higher for strange stars. Moreover, the amount of matter that becomes gravitationally unbound during the merging is determined. The detection of ejecta of strange star mergers as potential component of cosmic ray flux could serve as a proof of the existence of strange quark matter. (orig.)

  20. Relativistic simulations of compact object mergers for nucleonic matter and strange quark matter

    International Nuclear Information System (INIS)

    Bauswein, Andreas Ottmar

    2010-01-01

    Under the assumption that the energy of the ground state of 3-flavor quark matter is lower than the one of nucleonic matter, the compact stellar remnants of supernova explosions are composed of this quark matter. Because of the appearance of strange quarks, such objects are called strange stars. Considering their observational features, strange stars are very similar to neutron stars made of nucleonic matter, and therefore observations cannot exclude the existence of strange stars. This thesis introduces a new method for simulating mergers of compact stars and black holes within a general relativistic framework. The main goal of the present work is the investigation of the question, whether the coalescence of two strange stars in a binary system yields observational signatures that allow one to distinguish them from colliding neutron stars. In this context the gravitational-wave signals are analyzed. It is found that in general the characteristic frequencies in the gravitational-wave spectra are higher for strange stars. Moreover, the amount of matter that becomes gravitationally unbound during the merging is determined. The detection of ejecta of strange star mergers as potential component of cosmic ray flux could serve as a proof of the existence of strange quark matter. (orig.)

  1. Searching for Strange Quark Matter Objects in Exoplanets

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Y. F.; Yu, Y. B., E-mail: hyf@nju.edu.cn [Department of Astronomy, School of Astronomy and Space Science, Nanjing University, Nanjing 210023 (China)

    2017-10-20

    The true ground state of hadronic matter may be strange quark matter (SQM). Consequently, observed pulsars may actually be strange quark stars, but not neutron stars. However, proving or disproving the SQM hypothesis still remains a difficult problem to solve due to the similarity between the macroscopical characteristics of strange quark stars and neutron stars. Here, we propose a hopeful method to probe the existence of SQM. In the framework of the SQM hypothesis, strange quark dwarfs and even strange quark planets can also stably exist. Noting that SQM planets will not be tidally disrupted even when they get very close to their host stars due to their extreme compactness, we argue that we could identify SQM planets by searching for very close-in planets among extrasolar planetary systems. Especially, we should keep our eyes on possible pulsar planets with orbital radius less than ∼5.6 × 10{sup 10} cm and period less than ∼6100 s. A thorough search in the currently detected ∼2950 exoplanets around normal main-sequence stars has failed to identify any stable close-in objects that meet the SQM criteria, i.e., lying in the tidal disruption region for normal matter planets. However, the pulsar planet PSR J1719-1438B, with an orbital radius of ∼6 × 10{sup 10} cm and orbital period of 7837 s, is, encouragingly, found to be a good candidate.

  2. Aspects of strangeness

    International Nuclear Information System (INIS)

    Dover, C.B.

    1995-01-01

    We review various aspects of strangeness production in relativistic heavy ion collisions from AGS to CERN energies. The experimental data are briefly summarized and various possible theoretical interpretations of these data are evaluated, such as quark-gluon- plasma (QGP), hadron gas (HG) thermal models, or event generators (cascade models). Some comments on the production of strange clusters are offered

  3. Is the nucleon strange?

    CERN Document Server

    Nowak, M A; Zahed, I

    1989-01-01

    The issue of the strangeness content of the proton in relation to a large σ π N term is examined using the instanton-antiinstanton description of the QCD ground state. Modulo plausible assumptions, our results indicate no strangeness admixture in the nucleon state at zero momentum transfer.

  4. Seismic Search for Strange Quark Matter

    Science.gov (United States)

    Teplitz, Vigdor

    2004-01-01

    Two decades ago, Witten suggested that the ground state of matter might be material of nuclear density made from up, down and strange quarks. Since then, much effort has gone into exploring astrophysical and other implications of this possibility. For example, neutron stars would almost certainly be strange quark stars; dark matter might be strange quark matter. Searches for stable strange quark matter have been made in various mass ranges, with negative, but not conclusive results. Recently, we [D. Anderson, E. Herrin, V. Teplitz, and I. Tibuleac, Bull. Seis. Soc. of Am. 93, 2363 (2003)] reported a positive result for passage through the Earth of a multi-ton "nugget" of nuclear density in a search of about a million seismic reports, to the U.S. Geological Survey for the years 1990-93, not associated with known Earthquakes. I will present the evidence (timing of first signals to the 9 stations involved, first signal directions, and unique waveform characteristics) for our conclusion and discuss potential improvements that could be obtained from exploiting the seismologically quieter environments of the moon and Mars.

  5. Translation and discriminative validation of the STarT Back Screening Tool into Danish

    DEFF Research Database (Denmark)

    Morsø, Lars; Albert, Hanne; Kent, Peter

    2011-01-01

    OBJECTIVE: The STarT Back Screening Tool (STarT) is a nine-item patient self-report questionnaire that classifies low back pain patients into low, medium or high risk of poor prognosis. When assessed by GPs, these subgroups can be used to triage patients into different evidence-based treatment pa...

  6. Nucleation of strange matter in dense stellar cores

    International Nuclear Information System (INIS)

    Horvath, J.E.; Benvenuto, O.G.; Vucetich, H.

    1992-01-01

    We investigate the nucleation of strange quark matter inside hot, dense nuclear matter. Applying Zel'dovich's kinetic theory of nucleation we find a lower limit of the temperature T for strange-matter bubbles to appear, which happens to be satisfied inside the Kelvin-Helmholtz cooling era of a compact star life but not much after it. Our bounds thus suggest that a prompt conversion could be achieved, giving support to earlier expectations for nonstandard type-II supernova scenarios

  7. Theoretical perspective on strangeness production

    Directory of Open Access Journals (Sweden)

    Ko Che Ming

    2018-01-01

    Full Text Available A brief review of some highlights and puzzles on strangeness production in heavy ion collisions is given. These include strangeness production and the nuclear equation of state; deeply subthreshold strangeness production; mean-field potentials on strange hadrons; phi meson in dense matter; anomalous strange hadron to pion ratios; density fluctuations on particle production; A hyperon polarization and the vorticity field, and exotic hadrons.

  8. The PANDA physics program: Strangeness and more

    Energy Technology Data Exchange (ETDEWEB)

    Iazzi, Felice, E-mail: felice.iazzi@polito.it [INFN-Sezione di Torino, Turin (Italy); Politecnico di Torino, Turin (Italy); Collaboration: PANDA Collaboration

    2016-06-21

    The physics program of the PANDA experiment at FAIR is illustrated, with a particular attention to the planned activity in the field of the doubly strange systems. The investigation of these systems can help, among others, to shed light on the role of the hyperons in the composition of the neutron stars. The great advantages that can be reached in the field of the charmed systems and nucleon structure by using high quality and intense antiproton beams are also recalled.

  9. The PANDA physics program: Strangeness and more

    International Nuclear Information System (INIS)

    Iazzi, Felice

    2016-01-01

    The physics program of the PANDA experiment at FAIR is illustrated, with a particular attention to the planned activity in the field of the doubly strange systems. The investigation of these systems can help, among others, to shed light on the role of the hyperons in the composition of the neutron stars. The great advantages that can be reached in the field of the charmed systems and nucleon structure by using high quality and intense antiproton beams are also recalled.

  10. Strange Light Nuclei

    Directory of Open Access Journals (Sweden)

    Nakamura Satoshi N.

    2014-04-01

    Full Text Available “Strange” means 1 unusual or surprising, especially in a way that is difficult to explain or understand or 2 having strangeness degree of freedom. Light nuclear systems with strangeness, light hypernuclei, are perfect playground to study baryon force which would be a bridge between well established nuclear force in low energy region and QCD, the first principle of the strong interaction. Overview of study of light hypernuclei is given and recent experimental findings are reviewed.

  11. Characterisation of a dense state of quarks and gluons by the multi-strange hyperons excitation functions as measured with the Star experiment at RHIC; Caracterisation d'un etat dense de quarks et de gluons grace aux fonctions d'excitation des hyperons multi-etranges mesurees avec l'experience STAR au RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Speltz, J

    2006-10-15

    In this work, we characterize the production of the multi-strange baryons Xi and Omega in Au+Au collisions at RHIC, where the possible formation of a matter of deconfined quarks and gluons (QGP) is expected. We analyze with the STAR experiment, the collisions obtained at an energy of 62 GeV, intermediate between the one reached at the SPS (17 GeV) and the nominal energy of RHIC (200 GeV). Transverse momentum spectra, yields and elliptic flow are measured with different methods allowing for a relevant estimation of systematic errors. The results are compared to statistical and hydrodynamic models that we have adapted for their use at 62 GeV. The so obtained chemical and dynamic properties of the created medium indicate the formation of a thermalized, at least partially, medium and suggests the formation of a comparable matter at 62 GeV and at 200 GeV. (author)

  12. Multi-strangeness dynamics at PANDA

    Energy Technology Data Exchange (ETDEWEB)

    Gaitanos, Theodoros; Lenske, Horst; Mosel, Ulrich [Institut fuer Theoretische Physik, Universitaet Giessen (Germany)

    2014-07-01

    Multi-strange bound hadron systems are excellent candidates for studying in-medium hyperon-hyperon (YY) interactions. A better understanding of the strangeness sector of the hadronic equation of state is crucial for our understanding of astrophysical objects like neutron stars. Furthermore, these studies are being motivated by actual and planed experimental activities on hypernuclear physics (HypHI and PANDA Collaborations). In fact, HypHI has already studied single-strange hypernuclei in heavy-ion collisions, whereas studies on double- and multi-strange nuclear systems are being planed by PANDA. We have reported in the past first studies on single- and double-Λ hypernuclei production in reactions induced by heavy-ions and antiprotons, respectively. The YY-interaction is still little known and many controversial theoretical predictions exist in the literature. We therefore extend our previous works by investigating the influence of various hyperon-hyperon interactions on the production dynamics of multi-Λ hypernuclei in reactions relevant for FAIR. Particular attention is paid to the heavy Ω-baryon (S=-3) and its role to the formation of multi-Λ hypernuclei in reactions induced by antiprotons.

  13. Strange pathways for black hole formation

    International Nuclear Information System (INIS)

    Prakash, M.

    2000-01-01

    Immediately after they are born, neutron stars are characterized by an entropy per baryon of order unity and by the presence of trapped neutrinos. If the only hadrons in the star are nucleons, these effects slightly reduce the maximum mass relative to cold, catalyzed matter. However, if strangeness-bearing hyperons, a kaon condensate, or quarks are also present, these effects result in an increase in the maximum mass of up to ∼ 0.3M [odot] compared to that of a cold, neutrino-free star. This makes a sufficiently massive proto-neutron star metastable, so that after a delay of 10-100 seconds, the PNS collapses into a black hole. Such an event might be straightforward to observe as an abrupt cessation of neutrinos when the instability is triggered

  14. Nucleon strangeness: present and future

    CERN Document Server

    Sapozhnikov, M G

    2010-01-01

    A review of experimental results for the measurement of the strange quark distributions in the nucleon, is given. Contributions of the strange quarks to the nucleon mass, electromagnetic form factors and spin, are discussed.

  15. A Fat strange Repeller

    Institute of Scientific and Technical Information of China (English)

    申影; 何阅; 姜玉梅; 何大韧

    2004-01-01

    This article reports an observation on a fat strange repeller, which appears after a characteristic crisis observed in a kicked rotor subjected to a piecewise continuous force field. The discontinuity border in the definition range of the two-dimensional mapping, which describes the system, oscillates as the discrete time develops. At a threshold of a control parameter a fat chaotic attractor suddenly transfers to a fat transient set. The strange repeller, which appears after the crisis, is also a fat fractal. This is the reason why super-transience happens

  16. Strangeness at SIS energies

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Volker

    2005-09-28

    In this contribution the authors discuss the physics of strange hadrons in low energy ({approx_equal} 1-2 AGeV) heavy ion collision. In this energy range the relevant strange particle are the kaons and anti-kaons. The most interesting aspect concerning these particles are so called in-medium modifications. They will attempt to review the current status of understanding of these in medium modifications. In addition they briefly discuss other issues related with kaon production, such as the nuclear equation of state and chemical equilibrium.

  17. Chemical and dynamics properties of heavy ion collisions at RHIC energies by the measurement of the production of the doubly strange baryons in the STAR experiment

    International Nuclear Information System (INIS)

    Estienne, M.

    2005-04-01

    Lattice QCD calculations predict, at μ B ∼ 0, a crossover from ordinary hadronic matter to a Quark Gluon Plasma. Heavy ion collisions have been proposed to recreate it in the laboratory and to study its properties. The Au+Au, d+Au collisions at √(S NN ) = 200 GeV and the Au+Au ones at 62.4 GeV delivered at RHIC have been probed by the measurement of the Ξ particles in the STAR experiment. Their yield evolution with collision energy and system size gives size to the chemical properties of the reaction in the framework of hadronic and statistical models. The Ξ R CP shows: (1) a meson/baryon dependence for 2 pT CP suppression at pT > 3 GeV/c, (3) strong interactions between constituents suggesting the existence of strong collectivity in the medium. The Ξ transverse flow seems to be interesting to probe the early stage the collision with presumably partonic degrees of freedom. (author)

  18. Concurrent and discriminant validity of the Star Excursion Balance Test for military personnel with lateral ankle sprain.

    Science.gov (United States)

    Bastien, Maude; Moffet, Hélène; Bouyer, Laurent; Perron, Marc; Hébert, Luc J; Leblond, Jean

    2014-02-01

    The Star Excursion Balance Test (SEBT) has frequently been used to measure motor control and residual functional deficits at different stages of recovery from lateral ankle sprain (LAS) in various populations. However, the validity of the measure used to characterize performance--the maximal reach distance (MRD) measured by visual estimation--is still unknown. To evaluate the concurrent validity of the MRD in the SEBT estimated visually vs the MRD measured with a 3D motion-capture system and evaluate and compare the discriminant validity of 2 MRD-normalization methods (by height or by lower-limb length) in participants with or without LAS (n = 10 per group). There is a high concurrent validity and a good degree of accuracy between the visual estimation measurement and the MRD gold-standard measurement for both groups and under all conditions. The Cohen d ratios between groups and MANOVA products were higher when computed from MRD data normalized by height. The results support the concurrent validity of visual estimation of the MRD and the use of the SEBT to evaluate motor control. Moreover, normalization of MRD data by height appears to increase the discriminant validity of this test.

  19. DECONSTRUCTING FALSE IDENTITY: EXPLORING GENDER DISCRIMINATION AND ROLE-PLAYING IN THE GIRL WHO TOUCHED THE STARS

    Directory of Open Access Journals (Sweden)

    Neeraj Sankhyan

    2016-02-01

    Full Text Available Mahesh Dattani, is an avant-garde Indian English dramatist known for his radical and unconventional dramatic themes. His plays are characterized by an extremely sensitive temperament that delves into the intricacies of the human nature and strives to expose the hypocrisy of the urban life and society. This paper discusses his play The Girl Who Touched the Stars as a quest for a lost identity. In doing so, the paper sheds light upon the underlying themes of gender discrimination, misogyny and role-playing that the playwright uses in this play to show how much these evils are rampant even amongst the educated classes of the society. Specifically, the paper explores the deconstruction of identity of the protagonist as employed by the playwright and examines the implications this technique has on the narrative of the play. The interconnection between the role-playing and the inherent theme of gender discrimination is also analyzed in order to see how these elements complement each other. Also, the paper comments on the efficacy of radio drama as a medium for handling a sensitive theme like this.

  20. Thermal evolution of compact stars

    International Nuclear Information System (INIS)

    Schaab, C.; Glendenning, N.K.

    1996-01-01

    A collection of modern, field-theoretical equations of state is applied to the investigation of cooling properties of compact stars. These comprise neutron stars as well as hypothetical strange-matter stars, made up of absolutely stable 3-flavor strange-quark matter. Various uncertainties in the behavior of matter at supernuclear densities, e.g., hyperonic degrees of freedom, behavior of coupling strengths in matter, pion and meson condensation, superfluidity, transition to quark matter, absolute stability of strange-quark matter, and last but not least the many-body technique itself are tested against the body of observed cooling data. (orig.)

  1. Strangeness in nuclei

    International Nuclear Information System (INIS)

    Dover, C.B.

    1988-01-01

    We review some of the motivations for the study of strange particle nuclear physics. A status report on recent progress in the spectroscopy of Λ and Σ hypernuclei is provided, as well as a discussion of future prospects for the study of S = /minus/1 and /minus/2 systems. The importance of the nuclear physics program at future high intensity hadron facilities is emphasized. 45 refs

  2. Strangeness in nuclear collisions

    International Nuclear Information System (INIS)

    Gazdzicki, M.; Roehrich, D.

    1996-01-01

    Data on the mean multiplicity of strange hadrons produced in minimum bias proton-proton and central nucleus-nucleus collisions at momenta between 2.8 and 400 GeV/c per nucleon have been compiled. The multiplicities for nucleon-nucleon interactions were constructed. The ratios of strange particle multiplicity to participant nucleon as well as to pion multiplicity are larger for central nucleus-nucleus collisions than for nucleon-nucleon interactions at all studied energies. The data at AGS energies suggest that the latter ratio saturates with increasing masses of the colliding nuclei. The strangeness to pion multiplicity ratio observed in nucleon-nucleon interactions increases with collision energy in the whole energy range studied. A qualitatively different behaviour is observed for central nucleus-nucleus collisions: the ratio rapidly increases when going from Dubna to AGS energies and changes little between AGS and SPS energies. This change in the behaviour can be related to the increase in the entropy production observed in central nucleus-nucleus collisions at the same energy range. The results are interpreted within a statistical approach. They are consistent with the hypothesis that the quark gluon plasma is created at SPS energies, the critical collision energy being between AGS and SPS energies. (orig.)

  3. Magnetic monopoles and strange matter

    International Nuclear Information System (INIS)

    Sanudo, J.; Segui, A.

    1985-07-01

    We show that, if the density of grand unified monopoles at T approx. = 200 MeV is of the order of or greater than 4.4 * 10 21 cm -3 , they annihilate all of the strange matter produced in the quagmahadron phase transition which the Universe undergoes at this temperature. We also study gravitational capture of monopoles by lumps of strange matter. This yields upper limits on the density of monopoles for different sizes of strange ball. (author)

  4. An effective equation of state for dense matter with strangeness

    International Nuclear Information System (INIS)

    Balberg, S.; Gal, A.

    1997-01-01

    An effective equation of state which generalizes the Lattimer-Swesty equation for nuclear matter is presented for matter at supernuclear densities including strange baryons. It contains an adjustable baryon potential energy density, based on models of local potentials for the baryon-baryon interactions. The features of the equation rely on the properties of nuclei for the nucleon-nucleon interactions, and mainly on experimental data from hypernuclei for the hyperon-nucleon and hyperon-hyperon interactions. The equation is used to calculate equilibrium compositions and thermodynamic properties of high density matter with strangeness in two astrophysical contexts: neutron star matter (transparent to neutrinos) and proto-neutron star matter (opaque to neutrinos). The effective equation of state reproduces typical properties of high density matter found in theoretical microscopic models. Of these, the main result is that hyperons appear in both types of matter at about twice the nuclear saturation density, and that their appearance significantly softens the equation of state. The range of maximal masses of neutron stars found in a comprehensive parameter survey is 1.4-1.7 M s un. Another typical result is that the maximal mass of a proto-neutron star with strange baryons is higher than that of an evolved neutron star (opposite to the case of nuclear matter), setting the stage for a ''delayed collapse'' scenario. (orig.)

  5. Strange culinary cncounters:

    DEFF Research Database (Denmark)

    Leer, Jonatan; Kjær, Katrine Meldgaard

    Strange Culinary Encounters: Stranger Fetishism in Cooking Shows In this paper, we will examine the ways in which the encountering of 'other' food cultures is played out in the two travelogue cooking shows Gordon's Great Escape and Jamie's Italian Escape, arguing that despite their ‘noble......’ intentions and ‘enlightened’ cosmopolitan approach to meeting the other (culinary culture), ultimately, Jamie and Gordon's respective culinary adventures work to create a social hierarchy in their own favor. Inspired by Sara Ahmed’s work on stranger fetishism, we will investigate how the two protagonist...

  6. Strangeness in nuclei

    International Nuclear Information System (INIS)

    Buettgen, R.; Holinde, K.; Holzenkamp, B.; Speth, J.

    1986-01-01

    We present further results of our general program, which is to construct meson-exchange potentials for hadronic systems involving strange particles. In this contribution we investigate the relationship between the free ΛN-interaction and the effective interactions inside of a nucleus. These polarization effects are taken into account within a generalized Brueckner G-matrix. Within this approximation we calculate the binding energy and effective mass of a Λ-particle in nuclear matter as well as the Landau-parameters of the ΛN-system

  7. Strange experiments at the AGS

    International Nuclear Information System (INIS)

    Chrien, R.

    1990-01-01

    The purpose of this review is to report recent progress in nuclear experiments involving strangeness which have been carried out at the Brookhaven Alternating Gradient Synchrotron over the past three years. These recent developments are noted in three areas: few body systems and dibaryons; strange probes of the nucleus; and associated production of hypernuclei. 9 refs., 3 figs

  8. Overview of strangeness nuclear physics

    International Nuclear Information System (INIS)

    Gibson, B.F.

    1998-01-01

    Novel as well as puzzling aspects of strangeness (S = -1 and S = -2) nuclear physics are highlighted. Opportunities to gain new insights into hypernuclear spectroscopy, structure, and weak decays and to contribute to the continuing effort to understand the fundamental baryon-baryon force are outlined. Connections to strangeness in heavy-ion reactions and astrophysics are noted

  9. Towards Strange Metallic Holography

    International Nuclear Information System (INIS)

    2010-01-01

    We initiate a holographic model building approach to 'strange metallic' phenomenology. Our model couples a neutral Lifshitz-invariant quantum critical theory, dual to a bulk gravitational background, to a finite density of gapped probe charge carriers, dually described by D-branes. In the physical regime of temperature much lower than the charge density and gap, we exhibit anomalous scalings of the temperature and frequency dependent conductivity. Choosing the dynamical critical exponent z appropriately we can match the non-Fermi liquid scalings, such as linear resistivity, observed in strange metal regimes. As part of our investigation we outline three distinct string theory realizations of Lifshitz geometries: from F theory, from polarized branes, and from a gravitating charged Fermi gas. We also identify general features of renormalization group flow in Lifshitz theories, such as the appearance of relevant charge-charge interactions when z (ge) 2. We outline a program to extend this model building approach to other anomalous observables of interest such as the Hall conductivity.

  10. Strangeness nuclear physics

    International Nuclear Information System (INIS)

    Imai, Kenichi

    1999-01-01

    A simple review of strangeness nuclear physics is stated in the order of introduction, generation, structure and decay of hyper-nucleus and S=-2 nuclear physics. Strangeness nuclear physics investigate the structure and nuclear force of new created nucleus by introducing strangeness to the nuclear matter. The fundamental problems are hyperon-nucleon and hyperon-hyperon interaction. There are many methods to generate hyper nucleus. The stopped K - reaction is the best one. Λ and S hyper and S=-2 nucleus were generated by (K - , π) and (π + , K + ) reaction, (K - , π) reaction and (K - , K + ) reaction, respectively. The elementary decay process in the nucleus is Λ - > pπ (Q=38 MeV), nπ 0 and Λp - > np (Q=176 MeV), Λn- > nn. In emulsion, mass of light nucleus less than 160 were determined. Two measurement units are stated. One of them is a double focusing type K beam line in BNL to investigate H dibaryon by (K - , K + ) reaction. The other is KEK-SKS, which is superconducting kaon spectrometer to study hyper nucleus by (π + , K + ) reaction. The various kinds of binding energy of Λ single-particle states are displayed as a function of A -2/3 . These experimental data fit well with DWIA calculation using Woods-Saxon type one-body potential. A spectrum of 12C (π + , K + ) reaction showed small peak without main two peaks, which was a hyperfine structure between the exited state of 11 C core and couple of s 1/2 Λ. Although γ-ray was detected by three nucleuses such as 4 HΛ, 7 Li Λ and 9 Be Λ , γ-ray spectrometry of hyper nucleus remains unexplored. E hyper nucleus is detected by 4He(K-, t) and not by 4 He (K - , π + ). The binding energy of 4He Σ is 4.4 + 1 MeV and the width 7.0 + 0.7 MeV. Λ hyper nucleus decay is occurred by weak interaction. The elementary processes are a mesonic decay of Λ - > pπ - and Λ - > nπ 0 and a nonmesonic decay of Λn - > nn and Λp- > np. The lifetime of hyper nucleus is shorter than free Λ. Subject of S=-2 nuclear

  11. Today's View on Strangeness

    CERN Document Server

    Ellis, Jonathan Richard

    2005-01-01

    There are several different experimental indications, such as the pion-nucleon sigma term and polarized deep-inelastic scattering, which suggest that the nucleon wave function contains a hidden s bar s component. This is expected in chiral soliton models, which also predicted the existence of new exotic baryons that may recently have been observed. Another hint of hidden strangeness in the nucleon is provided by copious phi production in various N bar N annihilation channels, which may be due to evasions of the Okubo-Zweig-Iizuka rule. One way to probe the possible polarization of hidden s bar s pairs in the nucleon may be via Lambda polarization in deep-inelastic scattering.

  12. ALICE Masterclass on strangeness

    Directory of Open Access Journals (Sweden)

    Foka Panagiota

    2014-04-01

    Full Text Available An educational activity, the International Particle Physics Masterclasses, was developed by the International Particle Physics Outreach Group with the aim to bring the excitement of cutting-edge particle-physics research into the classroom. Thousands of pupils, every year since 2005, in many countries all over the world, are hosted in research centers or universities close to their schools and become “scientists for a day” as they are introduced to the mysteries of particle physics. The program of a typical day includes lectures that give insight to topics and methods of fundamental research followed by a “hands-on” session where the high-school students perform themselves measurements on real data from particle-physics experiments. The last three years data from the ALICE experiment at LHC were used. The performed measurement “strangeness enhancement” and the employed methodology are presented.

  13. Rotating Stars in Relativity

    Directory of Open Access Journals (Sweden)

    Stergioulas Nikolaos

    2003-01-01

    Full Text Available Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on the equilibrium properties and on the nonaxisymmetric instabilities in f-modes and r-modes have been updated and several new sections have been added on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity.

  14. Controlling Strange Attractor in Dynamics

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A nonlinear system which exhibits a strange attractor is considered, with the goal of illustrating how to control the chaotic dynamical system and to obtain a desired attracting periodic orbit by the OGY control algorithm.

  15. Strange mesonic transition form factor

    International Nuclear Information System (INIS)

    Goity, J.L.; Musolf, M.J.

    1996-01-01

    The strange-quark vector current ρ-to-π meson transition form factor is computed at one-loop order using strange meson intermediate states. A comparison is made with a φ-meson dominance model estimate. We find that one-loop contributions are comparable in magnitude to those predicted by φ-meson dominance. It is possible that the one-loop contribution can make the matrix element as large as those of the electromagnetic current mediating vector meson radiative decays. However, due to the quadratic dependence of the one-loop results on the hadronic form factor cutoff mass, a large uncertainty in the estimate of the loops is unavoidable. These results indicate that non-nucleonic strange quarks could contribute appreciable in moderate-parallel Q 2 parallel parity-violating electron-nucleus scattering measurements aimed at probing the strange-quark content of the nucleon. copyright 1996 The American Physical Society

  16. Theoretical Issues in Strangeness Production

    International Nuclear Information System (INIS)

    Laget, Jean-Marc

    2000-01-01

    After pioneering works on hypernuclei, strangeness production mechanisms have been studied in hadron collisions and photoreactions in the sixties. Recent experiments at SATURNE and COSY, in the hadronic sector, as well as ELSA and JLab, in the electromagnetic sector, have confirmed our basic ideas on the reaction mechanisms. In the near future, strangeness production at JLab, HERMES and COMPASS may prove to be a powerful tool to study hadronic matter

  17. Electro and photoproduction of strangeness

    International Nuclear Information System (INIS)

    Bertini, R.

    1988-01-01

    Strangeness-production studies and the characteristics of the electron accelerators applied in the experiments are discussed. The strangeness of the nucleon, the polarization in hyperon production, strange dybaryons, hypernuclei and baryons resonance and strangeness are the main topics. The importance of the electromagnetic probe as a tool in hyperon polarization measurements, in order to understand why hyperons become polarized at large momentum transfer, is underlined. High beam energies (30 GeV or so) and targets are needed for the study of the nucleon spin functions, as well as transverse and longitudinal polarization of the beam must be provided. In the following studies the needed energy range has been determinated: for the study of the strangeness content of the nucleon a beam energy higher than 3-4 GeV, in the search of H and D baryons, energies higher than 4 GeV, for the production of hypernuclei, the hyperon polarization and the baryon resonances study, beam energies ranging in the 3-4 GeV gap are enough. The relation meson-nucleon sigma terms to the strange quark content of the nucleon is discussed. In the measurement of the K-N sigma term, low energy Kaon beams and, possibly, polarized targets are needed

  18. Highlights from STAR

    International Nuclear Information System (INIS)

    Schweda, Kai

    2004-01-01

    Selected results from the STAR collaboration are presented. We focus on recent results on jet-like correlations, nuclear modification factors of identified hadrons, elliptic flow of multi-strange baryons Ξ and Ω, and resonance yields. First measurements of open charm production at RHIC are presented

  19. Strange Baryon Physics in Full Lattice QCD

    International Nuclear Information System (INIS)

    Huey-Wen Lin

    2007-01-01

    Strange baryon spectra and form factors are key probes to study excited nuclear matter. The use of lattice QCD allows us to test the strength of the Standard Model by calculating strange baryon quantities from first principles

  20. Strangeness Suppression and Color Deconfinement

    Science.gov (United States)

    Satz, Helmut

    2018-02-01

    The relative multiplicities for hadron production in different high energy collisions are in general well described by an ideal gas of all hadronic resonances, except that under certain conditions, strange particle rates are systematically reduced. We show that the suppression factor γs, accounting for reduced strange particle rates in pp, pA and AA collisions at different collision energies, becomes a universal function when expressed in terms of the initial entropy density s0 or the initial temperature T of the produced thermal medium. It is found that γs increases from about 0.5 to 1.0 in a narrow temperature range around the quark-hadron transition temperature Tc ≃ 160 MeV. Strangeness suppression thus disappears with the onset of color deconfinement; subsequently, full equilibrium resonance gas behavior is attained.

  1. Observational Constraints on Quark Matter in Neutron Stars

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We study the observational constraints of mass and redshift on the properties of the equation of state (EOS) for quark matter in compact stars based on the quasi-particle description. We discuss two scenarios: strange stars and hybrid stars. We construct the equations of state utilizing an extended MIT bag model taking the medium effect into account for quark matter and the relativistic mean field theory for hadron matter. We show that quark matter may exist in strange stars and in the interior of neutron stars. The bag constant is a key parameter that affects strongly the mass of strange stars. The medium effect can lead to the stiffer hybrid-star EOS approaching the pure hadronic EOS, due to the reduction of quark matter, and hence the existence of heavy hybrid stars. We find that a middle range coupling constant may be the best choice for the hybrid stars being compatible with the observational constraints.

  2. Production of strange particles in hadronization processes

    International Nuclear Information System (INIS)

    Hofmann, W.

    1987-08-01

    Strange particles provide an important tool for the study of the color confinement mechanisms involved in hadronization processes. We review data on inclusive strange-particle production and on correlations between strange particles in high-energy reactions, and discuss phenomenological models for parton fragmentation. 58 refs., 24 figs

  3. Strangeness production at high baryon density

    Energy Technology Data Exchange (ETDEWEB)

    Satz, Helmut [Universitaet Bielefeld, Fakultaet fuer Physik, Bielefeld (Germany)

    2016-08-15

    We propose to measure strange and non-strange hadron abundances at NICA in both AA and pp collisions, in order to test the validity range and possible extension schemes for present explanations of the energy and collision dependence of strange particle suppression. (orig.)

  4. Strange matter and Big Bang helium synthesis

    International Nuclear Information System (INIS)

    Madsen, J.; Riisager, K.

    1985-01-01

    Stable strange quark matter produced in the QCD phase transition in the early universe will trap neutrons and repel protons, thus reducing primordial helium production, Ysub(p). For reasonable values of Ysub(p), the radius of strange droplets must exceed 10 -6 cm if strange matter shall solve the dark-matter problem without spoiling Big Bang helium synthesis. (orig.)

  5. Strange Hadronic Matter in a Chiral Model

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-Liang; SONG Hong-Qiu; WANG Ping; SU Ru-Keng

    2000-01-01

    The strange hadronic matter with nucleon, Λ-hyperon and E-hyperon is studied by using a chiral symmetry model in a mean-field approximation. The saturation properties and stabilities of the strange hadronic matter are discussed. The result indicates a quite large strangeness fraction (fs) region where the strange hadronic matter is stable against particle emission. In the large fs region, the component dominates, resulting in a deep minimum in the curve of the binding energy per baryon EB versus the strangeness fraction fs with (EB, fs) -~ (-26.0MeV, 1.23).

  6. A strange cat in Dublin

    Science.gov (United States)

    O'Raifeartaigh, Cormac

    2012-11-01

    Not many life stories in physics involve Nazis, illicit sex, a strange cat and the genetic code. Thus, a new biography of the great Austrian physicist Erwin Schrödinger is always of interest, and with Erwin Schrödinger and the Quantum Revolution, veteran science writer John Gribbin does not disappoint.

  7. Strange matter and dihyperon physics

    International Nuclear Information System (INIS)

    Barnes, P.D.

    1986-01-01

    A short review of the properties of Strange Matter is followed by a discussion of dihyperon physics. Calculations of the mass, lifetime and decay modes of the H particle are discussed, along with a review of experiments designed to search for the H Dibaryon. 32 refs., 15 figs

  8. Will strangeness win the prize?

    Energy Technology Data Exchange (ETDEWEB)

    Kapusta, Joseph I. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States). E-mail: kapusta at physics.spa.umn.edu

    2001-03-01

    Five groups have made predictions involving the production of strange hadrons and entered them in a competition set up by Barbara Jacak, Xin-Nian Wang and myself in the spring of 1998 for the purpose of comparing with first-year physics results from RHIC. These predictions are summarized and evaluated. (author)

  9. The discrimination between star-forming and AGN galaxies in the absence of Hαand [NII]: A machine learning approach

    Science.gov (United States)

    Teimoorinia, H.; Keown, J.

    2018-05-01

    In the absence of the two emission lines Hαand [NII] (6584Å) in a BPT diagram, we show that other spectral information is sufficiently informative to distinguish AGN galaxies from star-forming galaxies. We use pattern recognition methods and a sample of galaxy spectra from the Sloan Digital Sky Survey (SDSS) to show that, in this survey, the flux and equivalent width of [OIII] (5007Å) and Hβ, along with the 4000Å break, can be used to classify galaxies in a BPT diagram. This method provides a higher accuracy of predictions than those which use stellar mass and [OIII]/Hβ. First, we use BPT diagrams and various physical parameters to re-classify the galaxies. Next, using confusion matrices, we determine the `correctly' predicted classes as well as confused cases. In this way, we investigate the effect of each parameter in the confusion matrices and rank the physical parameters used in the discrimination of the different classes. We show that in this survey, for example, {g - r} colour can provide the same accuracy as galaxy stellar mass to predict whether or not a galaxy hosts an AGN. Finally, with the same information, we also rank the parameters involved in the discrimination of Seyfert and LINER galaxies.

  10. Can doubly strange dibaryon resonances be discovered at RHIC?

    International Nuclear Information System (INIS)

    Paganis, S. D.; Hoffmann, G. W.; Ray, R. L.; Tang, J.-L.; Udagawa, T.; Longacre, R. S.

    2000-01-01

    The baryon-baryon continuum invariant mass spectrum generated from relativistic nucleus + nucleus collision data may reveal the existence of doubly strange dibaryons not stable against strong decay if they lie within a few MeV of threshold. Furthermore, since the dominant component of these states is a superposition of two color-octet clusters which can be produced intermediately in a color-deconfined quark-gluon plasma (QGP), an enhanced production of dibaryon resonances could be a signal of QGP formation. A total of eight, doubly strange dibaryon states are considered for experimental search using the STAR detector (solenoidal tracker at RHIC) at the new Relativistic Heavy Ion Collider (RHIC). These states may decay to ΛΛ and/or pΞ - , depending on the resonance energy. STAR's large acceptance, precision tracking and vertex reconstruction capabilities, and large data volume capacity, make it an ideal instrument to use for such a search. Detector performance and analysis sensitivity are studied as a function of resonance production rate and width for one particular dibaryon which can directly strong decay to pΞ - , but not ΛΛ. Results indicate that such resonances may be discovered using STAR if the resonance production rates are comparable to coalescence model predictions for dibaryon bound states. (c) 2000 The American Physical Society

  11. Strange functions in real analysis

    CERN Document Server

    Kharazishvili, AB

    2005-01-01

    Weierstrass and Blancmange nowhere differentiable functions, Lebesgue integrable functions with everywhere divergent Fourier series, and various nonintegrable Lebesgue measurable functions. While dubbed strange or "pathological," these functions are ubiquitous throughout mathematics and play an important role in analysis, not only as counterexamples of seemingly true and natural statements, but also to stimulate and inspire the further development of real analysis.Strange Functions in Real Analysis explores a number of important examples and constructions of pathological functions. After introducing the basic concepts, the author begins with Cantor and Peano-type functions, then moves to functions whose constructions require essentially noneffective methods. These include functions without the Baire property, functions associated with a Hamel basis of the real line, and Sierpinski-Zygmund functions that are discontinuous on each subset of the real line having the cardinality continuum. Finally, he considers e...

  12. Strange quark matter in the Universe and accelerator nuclear beams

    International Nuclear Information System (INIS)

    Okonov, Eh.

    1995-01-01

    An almost symmetric mixture of u, d and s-quarks - Strange Quark Matter (SQM) is strongly argued to be the ground and absolutely stable of the matter. Astrophysical objects, supposed to be the SQM states, could be formed as the result of the Big Bang (in the early Universe) and the conversion of neutron stars into strange ones. Such objects are considered to be favourable candidates as black holes. The unique possibility to produce the SQM under terrestrial conditions (at accelerator laboratories) are violent relativistic nucleus-nucleus collisions so called 'little big bang'. The expected singulares of SQM are reviewed which could be revealed from astrophysical observations of peculiarities of large SQM objects as well as from accelerator experiments with searching smaller SQM states including the simplest one - metastable six-quark H dihyperon. The first results of the Dubna search experiments, with considerable heating of matter and formation a dense strangeness abundant fireball (mixed phase?) in central nuclear collisions, is presented. Under these favourable conditions a candidate for H dihyperon is observed and an upper limit of production cross sections of this SQM state is estimated. Some prospects and advantages of further searches for light SQM states, using the JINR new superconducting accelerator - Nuclotron with energy 5-6 GeV per nucleon, are briefly outlined. 19 refs., 7 figs

  13. Thermodynamics of strange quark matter with the density-dependent bag constant

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The thermodynamics of strange quark matter with density dependent bag constant are studied self-consistently in the framework of the general ensemble theory and the MIT bag model.In our treatment,an additional term is found in the expression of pressure.With the additional term,the zero pressure locates exactly at the lowest energy state,indicating that our treatment is a self-consistently thermodynamic treatment.The self-consistent equations of state of strange quark matter in both the normal and color-flavor-locked phase are derived.They are both softer than the inconsistent ones.Strange stars in both the normal and color-flavor locked phase have smaller masses and radii in our treatment.It is also interesting to find that the energy density at a star surface in our treatment is much higher than that in the inconsistent treatment for both phases.Consequently,the surface properties and the corresponding observational properties of strange stars in our treatment are different from those in the inconsistent treatment.

  14. Thermodynamics of strange quark matter with the density-dependent bag constant

    Institute of Scientific and Technical Information of China (English)

    ZHU MingFeng; LIU GuangZhou; YU Zi; XU Yan; SONG WenTao

    2009-01-01

    The thermodynamics of strange quark matter with density dependent bag constant are studied selfconsistently in the framework of the general ensemble theory and the MIT bag model.In our treatment,an additional term Is found in the expression of pressure.With the additional term,the zero pressure locates exactly at the lowest energy state,Indicating that our treatment is a self-consistently thermodynamic treatment.The self-consistent equations of state of strange quark matter in both the normal and color-flavor-locked phase are derived.They are both softer than the inconsistent ones.Strange stars in both the normal and color-flavor locked phase have smaller masses and radii in our treatment.It is also interesting to find that the energy density at a star surface in our treatment is much higher than that In the inconsistent treatment for both phases.Consequently,the surface properties and the corresponding observational properties of strange stars in our treatment are different from those in the inconsistent treatment.

  15. 363. WE-Heraeus seminar on neutron stars and pulsars - 40 years after the discovery. Posters and contributed talks

    International Nuclear Information System (INIS)

    Becker, W.; Huang, H.H.

    2007-01-01

    The following topics were dealt with: X-ray observation of pulsars, gamma-ray observation of pulsars, radio observations of pulsars, theory of neutron stars and pulsars, AXPs, SGRs, and strange stars, gravitayional waves, analysis tools with software. (HSI)

  16. 363. WE-Heraeus seminar on neutron stars and pulsars - 40 years after the discovery. Posters and contributed talks

    Energy Technology Data Exchange (ETDEWEB)

    Becker, W; Huang, H H [eds.

    2007-07-01

    The following topics were dealt with: X-ray observation of pulsars, gamma-ray observation of pulsars, radio observations of pulsars, theory of neutron stars and pulsars, AXPs, SGRs, and strange stars, gravitayional waves, analysis tools with software. (HSI)

  17. Rotating stars in relativity.

    Science.gov (United States)

    Paschalidis, Vasileios; Stergioulas, Nikolaos

    2017-01-01

    Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on equilibrium properties and on nonaxisymmetric oscillations and instabilities in f -modes and r -modes have been updated. Several new sections have been added on equilibria in modified theories of gravity, approximate universal relationships, the one-arm spiral instability, on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity including both hydrodynamic and magnetohydrodynamic studies of these objects.

  18. Electromagnetic production of associated strangeness

    Energy Technology Data Exchange (ETDEWEB)

    David, J C [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; [CEA Centre d` Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d` Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l` Instrumentation Associee; Fayard, C; Lamot, G H [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Saghai, B [CEA Centre d` Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d` Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l` Instrumentation Associee

    1996-04-01

    A formalism, based on an isobaric approach using Feynman diagram techniques, which includes the nucleonic (spin {<=} 5/2), hyperonic (spin 1/2) and kaonic resonances, is developed. Using this formalism, a thorough investigation of electromagnetic strangeness processes is performed. A reaction mechanism, describing well enough the data, is found to include a reasonable number of baryonic resonances among a very large number of potential candidates. Predictions for the upcoming photoproduction polarization and electroproduction observables are presented, and their sensitivity to the phenomenological models ingredients are emphasized. (K.A.). 70 refs.; Submitted to Physical Review, C (US).

  19. Electromagnetic production of associated strangeness

    International Nuclear Information System (INIS)

    David, J.C.; CEA Centre d'Etudes de Saclay, 91 - Gif-sur-Yvette; Fayard, C.; Lamot, G.H.; Saghai, B.

    1996-04-01

    A formalism, based on an isobaric approach using Feynman diagram techniques, which includes the nucleonic (spin ≤ 5/2), hyperonic (spin 1/2) and kaonic resonances, is developed. Using this formalism, a thorough investigation of electromagnetic strangeness processes is performed. A reaction mechanism, describing well enough the data, is found to include a reasonable number of baryonic resonances among a very large number of potential candidates. Predictions for the upcoming photoproduction polarization and electroproduction observables are presented, and their sensitivity to the phenomenological models ingredients are emphasized. (K.A.)

  20. New strangeness results from HADES

    Czech Academy of Sciences Publication Activity Database

    Fabbietti, L.; Agakishiev, G.; Agodi, C.; Balanda, A.; Bellia, G.; Belver, D.; Belyaev, A.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Braun-Munzinger, P.; Cabanelas, P.; Castro, E.; Chernenko, S.; Christ, T.; Destefanis, M.; Díaz, J.; Dohrmann, F.; Dybczak, A.; Eberl, T.; Fateev, O.; Friese, J.; Frohlich, I.; Galatyuk, T.; Garzón, J.A.; Gernhäuser, R.; Gil, A.; Gilardi, C.; Golubeva, M.; Gonzalez-Diaz, D.; Grosse, E.; Guber, F.; Heilmann, M.; Hennino, T.; Holzman, R.; Ierusalimov, A.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Kanaki, K.; Karavicheva, T.; Kirschner, D.; Koenig, I.; Koenig, W.; Kolb, B.W.; Kotte, R.; Kozuch, A.; Krása, Antonín; Křížek, Filip; Krücken, R.; Kühn, W.; Kugler, Andrej; Kurepin, A.; Lamas-Valverde, J.; Lang, S.; Lange, J.S.; Lapidus, K.; Lopes, L.; Maier, L.; Mangiarotti, A.; Marín, J.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Mishra, D.; Moriniére, E.; Mousa, J.; Muntz, C.; Naumann, L.; Novotný, R.; Otwinowski, J.; Pachmayer, Y.C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Cavalcanti, T.P.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Roy-Stephan, M.; Rustamov, A.; Sadovsky, A.; Sailer, B.; Salabura, P.; Schmah, A.; Simon, R. S.; Sobolev, Yuri, G.; Spataro, S.; Spruck, B.; Strobele, H.; Stroth, J.; Sturm, C.; Sudol, M.; Tarantola, A.; Teilab, K.; Tlustý, Pavel; Traxler, M.; Trebacz, R.; Tsertos, H.; Veretenkin, I.; Wagner, Vladimír; Wen, H.; Wisniowski, M.; Wojcik, T.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y.V.; Zhou, P.; Zumbruch, P.

    2009-01-01

    Roč. 36, č. 6 (2009), 064005/1-064005/12 ISSN 0954-3899. [12th International Conference on Strangeness in Quark Matter. Beijing, 05.10.2008-10.10.2008] R&D Projects: GA AV ČR IAA100480803; GA MŠk LC07050 Institutional research plan: CEZ:AV0Z10480505 Keywords : heavy-ion collisions * kaon production * sis energies Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.124, year: 2009

  1. Strangeness production with protons and pions

    International Nuclear Information System (INIS)

    Dover, C.B.

    1993-01-01

    We discuss the spectrum of physics questions related to strangeness which could be addressed with intense beams of protons and pions in the few GeV region. We focus on various aspects of strangeness production, including hyperon production in pp collisions, studies of hyperon-nucleon scattering, production of hypernuclei in proton and pion-nucleus collisions, and spin phenomena in hypernuclei

  2. On the properties of strange quark matter

    International Nuclear Information System (INIS)

    Zhou Leming; Peng Guangxiong; Ning Pingzhi

    1999-01-01

    According to authors' recent studies, the authors derive a new mass formula for strange quarks at zero temperature. The authors apply it to investigating the properties of strange quark matter and obtain similar results to those in the MIT bag model. A different point in authors' results is that the variation of sound velocity with energy density becomes a little slower

  3. Strangeness fluctuations and MEMO production at FAIR

    International Nuclear Information System (INIS)

    Steinheimer, Jan; Mitrovski, Michael; Schuster, Tim; Petersen, Hannah; Bleicher, Marcus; Stoecker, Horst

    2009-01-01

    We apply a coupled transport-hydrodynamics model to discuss the production of multi-strange meta-stable objects in Pb + Pb reactions at the FAIR facility. In addition to making predictions for yields of these particles we are able to calculate particle dependent rapidity and momentum distributions. We argue that the FAIR energy regime is the optimal place to search for multi-strange baryonic object (due to the high baryon density, favoring a distillation of strangeness). Additionally, we show results for strangeness and baryon density fluctuations. Using the UrQMD model we calculate the strangeness separation in phase space which might lead to an enhanced production of MEMOs compared to models that assume global thermalization.

  4. How strange a non-strange heavy baryon?

    International Nuclear Information System (INIS)

    Zhitnitsky, A.R.

    1997-01-01

    We give some general arguments in favor of the large magnitude of matrix elements of an operator associated with nonvalence quarks in heavy hadrons. In particular, we estimate matrix element left angle Λ b vertical stroke ss vertical stroke Λ b right angle to be of order of 1 for Λ b baryon whose valence content is b, u, d quarks. The arguments are based on the QCD sum rules and low energy theorems. The physical picture behind the phenomenon is somewhat similar to the one associated with the large strange content of the nucleon, i.e. with the large magnitude of the matrix element left angle p vertical stroke ss vertical stroke p right angle ∼ 1. We discuss some possible applications of the result. (orig.)

  5. Strangeness by Thermal Model Simulation at RHIC

    Institute of Scientific and Technical Information of China (English)

    SHI Xing-Hua; MA Yu-Gang; CAI Xiang-Zhou; CHEN Jin-Hui; MA Guo-Liang; ZHONG Chen

    2009-01-01

    The local temperature effect on strangeness enhancement in relativistic heavy ion collisions is discussed in the framework of the thermal model in which the K+ /h+ ratio becomes smaller with increasing freeze-out temperature.Considering that most strangeness particles of final-state particles are from the kaon meson,the temperature effect may play a role in strangeness production in hot dense matter where a slightly different temperature distribution in different areas could be produced by jet energy loss.This phenomenon is predicted by thermal model calculation at RHIC energy.The Ε-/φ ratio in central Au+Au collisions at 200 GeV from the thermal model depends on the freeze-out temperature obviously when γs is different.It should be one of the reasons why strangeness enhancements of Ε and φ are different though they include two strange quarks.These results indicate that thermodynamics is an important factor for strangeness production and the strangeness enhancement phenomenon.

  6. Weak strange particle production: advantages and difficulties

    International Nuclear Information System (INIS)

    Angelescu, Tatiana; Baker, O.K.

    2002-01-01

    Electromagnetic strange particle production developed at Jefferson Laboratory was an important source of information on strange particle electromagnetic formfactors and induced and transferred polarization. The high quality of the beam and the detection techniques involved could be an argument for detecting strange particles in weak interactions and answer questions about cross sections, weak formfactors, neutrino properties, which have not been investigated yet. The paper analyses some aspects related to the weak lambda production and detection with the Hall C facilities at Jefferson Laboratory and the limitations in measuring the weak interaction quantities. (authors)

  7. Ultrarelativistic cascades and strangeness production

    Energy Technology Data Exchange (ETDEWEB)

    Kahana, D.E. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics; Kahana, S.H. [Brookhaven National Lab., Upton, NY (United States). Physics Dept.

    1998-08-24

    A two-phase cascade code, LUCIFER II, developed for the treatment of ultra high energy-ion-ion collisions is applied to the production of strangeness at SPS energies {radical}(s)=17-20. This simulation is able to simultaneously describe both hard processes such as Drell-Yan and slower, soft processes such as the production of light mesons by separating the dynamics into two steps, a fast cascade involving only the nucleons in the original colliding relativistic ions followed, after an appropriate delay, by a normal multiscattering of the resulting excited baryons and mesons produced virtually in the first step. No energy loss can take place in the short time interval over which the first cascade takes place. The chief result is a reconciliation of the important Drell-Yan measurements with the apparent success of standard cascades to describe the nucleon stopping and meson production in heavy-ion experiments at the CERN SPS. (orig.) 26 refs.

  8. Nuclear physics with strange particles

    International Nuclear Information System (INIS)

    Dover, C.B.

    1988-01-01

    Recent progress in the understanding of strange particle interactions with nuclear systems is reviewed. We discuss the relative merits of various reactions such as (K - , π/sup +-/), (π + , K + ), or (γ, K + ) for hypernuclear production. The structure of /sub Λ/ 13 C is analyzed in some detail, in order to illustrate the role of the ΛN residual interaction and approximate dynamical symmetries in hypernuclear structure. Recent results on the single particle states of a Λ in heavy systems, as revealed by (π + , K + ) reaction studies, are used to extract information on the density dependence and effective mass which characterize the Λ-nucleus mean field. Finally, we develop the idea the K + -nucleus scattering at low energies is sensitive to the subtle ''swelling'' effects for nucleons bound in nuclei. 64 refs., 13 figs

  9. Ultrarelativistic cascades and strangeness production

    International Nuclear Information System (INIS)

    Kahana, D.E.; Kahana, S.H.

    1998-01-01

    A two-phase cascade code, LUCIFER II, developed for the treatment of ultra high energy-ion-ion collisions is applied to the production of strangeness at SPS energies √(s)=17-20. This simulation is able to simultaneously describe both hard processes such as Drell-Yan and slower, soft processes such as the production of light mesons by separating the dynamics into two steps, a fast cascade involving only the nucleons in the original colliding relativistic ions followed, after an appropriate delay, by a normal multiscattering of the resulting excited baryons and mesons produced virtually in the first step. No energy loss can take place in the short time interval over which the first cascade takes place. The chief result is a reconciliation of the important Drell-Yan measurements with the apparent success of standard cascades to describe the nucleon stopping and meson production in heavy-ion experiments at the CERN SPS. (orig.)

  10. Ultrarelativistic cascades and strangeness production

    International Nuclear Information System (INIS)

    Kahana, D.E.; Kahana, S.H.

    1998-02-01

    A two phase cascade, LUCIFER II, developed for the treatment of ultra high energy Ion-Ion collisions is applied to the production of strangeness at SPS energies. This simulation is able to simultaneously describe both hard processes such as Drell-Yan and slower, soft processes such as the production of light mesons by separating the dynamics into two steps, a fast cascade involving only the nucleons in the original colliding relativistic ions followed, after an appropriate delay, by a normal multiscattering of the resulting excited baryons and mesons produced virtually in the first step. No energy loss can take place in the short time interval over which the first cascade takes place. The chief result is a reconciliation of the important Drell-Yan measurements with the apparent success of standard cascades to describe the nucleon stopping and meson production in heavy ion experiments at the CERN SPS

  11. Studying Strangeness Production with HADES

    Science.gov (United States)

    Schuldes, Heidi

    2018-02-01

    The High-Acceptance DiElectron Spectrometer (HADES) operates in the 1 - 2A GeV energy regime in fixed target experiments to explore baryon-rich strongly interacting matter in heavy-ion collisions at moderate temperatures with rare and penetrating probes. We present results on the production of strange hadrons below their respective NN threshold energy in Au+Au collisions at 1.23A GeV ( = 2.4 GeV). Special emphasis is put on the enhanced feed-down contribution of ϕ mesons to the inclusive yield of K- and its implication on the measured spectral shape of K-. Furthermore, we investigate global properties of the system, confronting the measured hadron yields and transverse mass spectra with a Statistical Hadronization Model (SHM) and a blastwave parameterization, respectively. These supplement the world data of the chemical and kinetic freeze-out temperatures.

  12. Introduction to neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Lattimer, James M. [Dept. of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

    2015-02-24

    Neutron stars contain the densest form of matter in the present universe. General relativity and causality set important constraints to their compactness. In addition, analytic GR solutions are useful in understanding the relationships that exist among the maximum mass, radii, moments of inertia, and tidal Love numbers of neutron stars, all of which are accessible to observation. Some of these relations are independent of the underlying dense matter equation of state, while others are very sensitive to the equation of state. Recent observations of neutron stars from pulsar timing, quiescent X-ray emission from binaries, and Type I X-ray bursts can set important constraints on the structure of neutron stars and the underlying equation of state. In addition, measurements of thermal radiation from neutron stars has uncovered the possible existence of neutron and proton superfluidity/superconductivity in the core of a neutron star, as well as offering powerful evidence that typical neutron stars have significant crusts. These observations impose constraints on the existence of strange quark matter stars, and limit the possibility that abundant deconfined quark matter or hyperons exist in the cores of neutron stars.

  13. Strange (and incompatible) bedfellows: The relationship between ...

    African Journals Online (AJOL)

    Strange (and incompatible) bedfellows: The relationship between the National Health Act and the regulations relating to artificial fertilisation of persons, and its impact on individuals engaged in assisted reproduction.

  14. Associated strangeness production at intermediate energies

    International Nuclear Information System (INIS)

    Saghai, B.

    1996-04-01

    Elementary strangeness production reactions with hadronic and electromagnetic probes are briefly reviewed. Some recent theoretical and experimental findings are underlined and a few open questions are singled out. (author)

  15. New experimental results on strangeness production

    International Nuclear Information System (INIS)

    Sapozhnikov, M.G.

    1998-01-01

    New experimental results on the production of φ and f 2 ' (1525) mesons in the annihilation of stopped antiprotons are discussed. The explanation of these facts in the framework of the polarized strangeness model is considered

  16. Strangeness production in heavy ion collisions

    International Nuclear Information System (INIS)

    Redlich, K.

    2001-05-01

    Strangeness production in heavy ion collisions is discussed in a broad energy range from SIS to RHIC. In the whole energy range particle yields are showing high level of chemical equilibration which can be described by the unified freezeout conditions of fixed energy/particle ≅ 1GeV. The statistical model within the canonical formulation of strangeness conservation provides a framework to describe the observed enhancement of (multi)strange particles from p+A to A+A collisions measured at the SPS energy and predicts that this enhancement should be larger for decreasing collision energy. However, only at the SPS and RHIC chemical freezeout temperature is consistent within error with the critical value required for deconfinement and simultaneously strangeness is uncorrelated and distributed in the whole volume of the fireball. (orig.)

  17. Charges on Strange Quark Nuggets in Space

    Science.gov (United States)

    Teplitz, V.; Bhatia, A.; Abers, E.; Dicus, D.; Repko, W.; Rosenbaum, D.

    2008-01-01

    This viewgraph presentation reviews the work done in calculations to find ZN such that the rate of ambient photons ionize the strange quark nuggets (SQNs) Electrons are equal to the rate of ambient e's to replace them.

  18. Strange Attractors in Drift Wave Turbulence

    International Nuclear Information System (INIS)

    Lewandowski, J.L.V.

    2003-01-01

    A multi-grid part-in-cell algorithm for a shearless slab drift wave model with kinetic electrons is presented. The algorithm, which is based on an exact separation of adiabatic and nonadiabatic electron responses, is used to investigate the presence of strange attractors in drift wave turbulence. Although the simulation model has a large number of degrees of freedom, it is found that the strange attractor is low-dimensional and that it is strongly affected by dissipative (collisional) effects

  19. Strange sea determination from collider data

    Science.gov (United States)

    Alekhin, S.; Blümlein, J.; Moch, S.

    2018-02-01

    We consider determinations of the strange sea in the nucleon based on QCD analyses of data collected at the LHC with focus on the recent high-statistics ATLAS measurement of the W±- and Z-boson production. We study the effect of different functional forms for parameterization of the parton distribution functions and the combination of various data sets in the analysis. We compare to earlier strange sea determinations and discuss ways to improve them in the future.

  20. Strange sea determination from collider data

    International Nuclear Information System (INIS)

    Alekhin, S.; Bluemlein, J.; Moch, S.

    2017-08-01

    We consider determinations of the strange sea in the nucleon based on QCD analyses of data collected at the LHC with focus on the recent high-statistics ATLAS measurement of the W ± - and Z-boson production. We study the effect of different functional forms for parameterization of the parton distribution functions and the combination of various data sets in the analysis. We compare to earlier strange sea determinations and discuss ways to improve them in the future.

  1. Strange sea determination from collider data

    Energy Technology Data Exchange (ETDEWEB)

    Alekhin, S. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Institut Fiziki Vysokikh Ehnergij, Protvino (Russian Federation); Bluemlein, J. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Moch, S. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2017-08-15

    We consider determinations of the strange sea in the nucleon based on QCD analyses of data collected at the LHC with focus on the recent high-statistics ATLAS measurement of the W{sup ±}- and Z-boson production. We study the effect of different functional forms for parameterization of the parton distribution functions and the combination of various data sets in the analysis. We compare to earlier strange sea determinations and discuss ways to improve them in the future.

  2. Towards a new generation of strangeness results

    International Nuclear Information System (INIS)

    Bellwied, Rene

    2004-01-01

    I will review the latest strangeness result measured in fixed target heavy-ion collisions at SIS, AGS and SPS before describing the first round of RHIC results. I will show that the systematic studies performed at the lower energies give a very consistent picture of enhanced strangeness production at SPS energies and hints of medium modification effects at the lower energies, which are dominated by larger baryon densities. The RHIC results complement this picture by again indicating strangeness production from a thermally equilibrated source, albeit at slightly higher freeze-out temperatures and lower baryon densities. RHIC adds significant new physics results to the field, though, by enabling the measurement of strange particle production at high transverse momentum, presently out to about 6 GeV/c. The new regime between 2 and 6 GeV/c is dominated by an interplay between traditional soft particle production, which is well described by hydrodynamical and thermal models, and production of strangeness from jet fragmentation. Potential new QGP signatures, such as jet quenching and elliptic flow due to parton collectivity, can be probed by measuring particle identified strange particle spectra out to high p t . I will review the latest results and show that these measurements breathe new life into a well-established field

  3. Energy dependence of strangeness production and event-byevent fluctuations

    Directory of Open Access Journals (Sweden)

    Rustamov Anar

    2018-01-01

    Full Text Available We review the energy dependence of strangeness production in nucleus-nucleus collisions and contrast it with the experimental observations in pp and p-A collisions at LHC energies as a function of the charged particle multiplicities. For the high multiplicity final states the results from pp and p-Pb reactions systematically approach the values obtained from Pb-Pb collisions. In statistical models this implies an approach to the thermodynamic limit, where differences of mean multiplicities between various formalisms, such as Canonical and Grand Canonical Ensembles, vanish. Furthermore, we report on event-by-event net-proton fluctuations as measured by STAR at RHIC/BNL and by ALICE at LHC/CERN and discuss various non-dynamical contributions to these measurements, which should be properly subtracted before comparison to theoretical calculations on dynamical net-baryon fluctuations.

  4. Production and energy loss of strange and heavy quarks

    International Nuclear Information System (INIS)

    2010-01-01

    Data taken over the last several years have demonstrated that RHIC has created a hot, dense medium with partonic degrees of freedom. Identified particle spectra at high transverse momentum (p T ) and heavy flavor that are thought to be well-calibrated probes thus serve as ideal tools to study the properties of the medium. We present p T distributions of particle ratios in p+p collisions from the STAR experiment to understand the particle production mechanisms. These measurements will also constrain fragmentation functions in hadron-hardon collisions. In heavy-ion collisions, we highlight (1) recent measurements of strange hadrons and heavy flavor decay electrons up to high p T to study jet interaction with the medium and explore partonic energy loss mechanisms, and (2) Υ and high p T J/ψ measurements to study the effect of color screening and other possible production mechanisms.

  5. Theoretical perspectives on strange physics

    International Nuclear Information System (INIS)

    Ellis, J.

    1983-04-01

    Kaons are heavy enough to have an interesting range of decay modes available to them, and light enough to be produced in sufficient numbers to explore rare modes with satisfying statistics. Kaons and their decays have provided at least two major breakthroughs in our knowledge of fundamental physics. They have revealed to us CP violation, and their lack of flavor-changing neutral interactions warned us to expect charm. In addition, K 0 -anti K 0 mixing has provided us with one of our most elegant and sensitive laboratories for testing quantum mechanics. There is every reason to expect that future generations of kaon experiments with intense sources would add further to our knowledge of fundamental physics. This talk attempts to set future kaon experiments in a general theoretical context, and indicate how they may bear upon fundamental theoretical issues. A survey of different experiments which would be done with an Intense Medium Energy Source of Strangeness, including rare K decays, probes of the nature of CP isolation, μ decays, hyperon decays and neutrino physics is given

  6. Supernovae, compact stars and nuclear physics

    International Nuclear Information System (INIS)

    Glendenning, N.K.

    1989-01-01

    We briefly review the current understanding of supernova. We investigate the implications of rapid rotation corresponding to the frequency of the new pulsar reported in the supernovae remnant SN1987A. It places very stringent conditions on the equation of state if the star is assumed to be bound by gravity alone. We find that the central energy density of the star must be greater than 12 times that of nuclear density to be stable against the most optimistic estimate of general relativistic instabilities. This is too high for the matter to plausibly consist of individual hadrons. We conclude that the newly discovered pulsar, if its half-millisecond signals are attributable to rotation, cannot be a neutron star. We show that it can be a strange quark star, and that the entire family of strange stars can sustain high rotation under appropriate conditions. We discuss the conversion of a neutron star to strange star, the possible existence of a crust of heavy ions held in suspension by centrifugal and electric forces, the cooling and other features. 39 refs., 8 figs., 2 tabs

  7. Towards a new generation of strangeness results

    CERN Document Server

    Bellwied, R

    2004-01-01

    I will review the latest strangeness result measured in fixed target heavy-ion collisions at SIS, AGS and SPS before describing the first round of RHIC results. I will show that the systematic studies performed at the lower energies give a very consistent picture of enhanced strangeness production at SPS energies and hints of medium modification effects at the lower energies, which are dominated by larger baryon densities. The RHIC results complement this picture by again indicating strangeness production from a thermally equilibrated source, albeit at slightly higher freeze-out temperatures and lower baryon densities. RHIC adds significant new physics results to the field, though, by enabling the measurement of strange particle production at high transverse momentum, presently out to about 6 GeV /c. The new regime between 2 and 6 GeV/c is dominated by an interplay between traditional soft particle production, which is well described by hydrodynamical and thermal models, and production of strangeness from jet...

  8. Strange hadron production at low transverse momenta

    Science.gov (United States)

    Veres, Gábor I.; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Noell, A.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sawicki, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Teng, R.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wyslouch, B.; Zhang, J.

    2004-01-01

    Some of the latest results of the PHOBOS experiment from the \\sqrt{s_{NN}}= 200\\ GeV Au+Au data are discussed. Those relevant to strangeness production are emphasized. These observations relate to the nature of the matter created when heavy ions collide at the highest achieved energy. The invariant yields of strange and non-strange charged hadrons at very low transverse momentum have been measured, and used to differentiate between different dynamical scenarios. In the intermediate transverse momentum range, the measured ratios of strange and anti-strange kaons approach one, while the antibaryon to baryon ratio is still significantly less, independent of collision centrality and transverse momentum. At high transverse momenta, we find that central and peripheral Au+Au collisions produce similar numbers of charged hadrons per participant nucleon pair, rather than per binary nucleon-nucleon collision. Finally, we describe the upgrades of PHOBOS completed for the 2003 d+Au and p+p run, which extend the transverse momentum range over which particle identification is possible and, at the same time, implement a trigger system selective for high-pT particles.

  9. General Relativity and Compact Stars

    International Nuclear Information System (INIS)

    Glendenning, Norman K.

    2005-01-01

    Compact stars--broadly grouped as neutron stars and white dwarfs--are the ashes of luminous stars. One or the other is the fate that awaits the cores of most stars after a lifetime of tens to thousands of millions of years. Whichever of these objects is formed at the end of the life of a particular luminous star, the compact object will live in many respects unchanged from the state in which it was formed. Neutron stars themselves can take several forms--hyperon, hybrid, or strange quark star. Likewise white dwarfs take different forms though only in the dominant nuclear species. A black hole is probably the fate of the most massive stars, an inaccessible region of spacetime into which the entire star, ashes and all, falls at the end of the luminous phase. Neutron stars are the smallest, densest stars known. Like all stars, neutron stars rotate--some as many as a few hundred times a second. A star rotating at such a rate will experience an enormous centrifugal force that must be balanced by gravity or else it will be ripped apart. The balance of the two forces informs us of the lower limit on the stellar density. Neutron stars are 10 14 times denser than Earth. Some neutron stars are in binary orbit with a companion. Application of orbital mechanics allows an assessment of masses in some cases. The mass of a neutron star is typically 1.5 solar masses. They can therefore infer their radii: about ten kilometers. Into such a small object, the entire mass of our sun and more, is compressed

  10. Delta isobars in neutron stars

    Directory of Open Access Journals (Sweden)

    Pagliara Giuseppe

    2015-01-01

    Full Text Available The appearance of delta isobars in beta-stable matter is regulated by the behavior of the symmetry energy at densities larger than saturation density. We show that by taking into account recent constraints on the density derivative of the symmetry energy and the theoretical and experimental results on the excitations of delta isobars in nuclei, delta isobars are necessary ingredients for the equations of state used for studying neutron stars. We analyze the effect of the appearance of deltas on the structure of neutron stars: as in the case of hyperons, matter containing delta is too soft for allowing the existence of 2M⊙ neutron stars. Quark stars on the other hand, could reach very massive configurations and they could form from a process of conversion of hadronic stars in which an initial seed of strangeness appears through hyperons.

  11. Search for a strangeness -2 dibaryon

    International Nuclear Information System (INIS)

    Franklin, G.B.

    1985-01-01

    The existing data on the strangeness -2 two-baryon mass spectrum is reviewed and a new experiment is proposed to explore this spectrum from 100 MeV below the mass of the lightest known two-baryon strangeness -2 system, ΛΛ, to 20 MeV above the ΛΛ mass. The proposed experiment is motivated by Jaffe's 1977 prediction of a six-quark object with strangeness -2 and J/sup π/ = 0 + at a mass of 2150. This particle, called the ''H'', has been predicted by later bag models as well. Calculations indicate the proposed experiment will be a sensitive test of the dibaryon theories. 12 refs

  12. Neutron stars velocities and magnetic fields

    Science.gov (United States)

    Paret, Daryel Manreza; Martinez, A. Perez; Ayala, Alejandro.; Piccinelli, G.; Sanchez, A.

    2018-01-01

    We study a model that explain neutron stars velocities due to the anisotropic emission of neutrinos. Strong magnetic fields present in neutron stars are the source of the anisotropy in the system. To compute the velocity of the neutron star we model its core as composed by strange quark matter and analice the properties of a magnetized quark gas at finite temperature and density. Specifically we have obtained the electron polarization and the specific heat of magnetized fermions as a functions of the temperature, chemical potential and magnetic field which allow us to study the velocity of the neutron star as a function of these parameters.

  13. Connecting coherent structures and strange attractors

    Science.gov (United States)

    Keefe, Laurence R.

    1990-01-01

    A concept of turbulence derived from nonlinear dynamical systems theory suggests that turbulent solutions to the Navier-Stokes equations are restricted to strange attractors, and, by implication, that turbulent phenomenology must find some expression or source in the structure of these mathematical objects. Examples and discussions are presented to link coherent structures to some of the commonly known characteristics of strange attractors. Basic to this link is a geometric interpretation of conditional sampling techniques employed to educe coherent structures that offers an explanation for their appearance in measurements as well as their size.

  14. Properties of Strange Matter in a Model with Effective Lagrangian

    Institute of Scientific and Technical Information of China (English)

    WANG Ping; SU Ru-Keng; SONG Hong-Qiu; ZHANG Li-Liang

    2001-01-01

    The strange hadronic matter with nucleons, A-hyperons and E-hyperons is studied by using an effective nuclear model in a mean-field approximation. The density and strangeness fraction dependence of the effective baryon masses as well as the saturation properties and stabilities of the strange hadronic matter are discussed.``

  15. Neutron stars

    International Nuclear Information System (INIS)

    Irvine, J.M.

    1978-01-01

    The subject is covered in chapters entitled: introduction (resume of stellar evolution, gross characteristics of neutron stars); pulsars (pulsar characteristics, pulsars as neutron stars); neutron star temperatures (neutron star cooling, superfluidity and superconductivity in neutron stars); the exterior of neutron stars (the magnetosphere, the neutron star 'atmosphere', pulses); neutron star structure; neutron star equations of state. (U.K.)

  16. Echolocation The Strange Ways of Bats

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 5. Echolocation The Strange Ways of Bats. G Marimuthu. General Article Volume 1 Issue 5 May 1996 pp 40-48. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/001/05/0040-0048. Author Affiliations.

  17. Strange diquarks and orbital excitations of hyperons

    International Nuclear Information System (INIS)

    Kondratyuk, L.A.; Ralchenko, Yu.V.; Vasilets, A.V.

    1987-01-01

    Using the model of the QCD string with spin-orbital interaction the masses of strange diquarks are determined. The spectra of orbital excitations of the Λ and Σ hyperons are calculated and discussed. Also the decay modes for Λ's and Σ's are considered

  18. CP asymmetries in Strange Baryon Decays

    Science.gov (United States)

    Bigi, I. I.; Kang, Xian-Wei; Li, Hai-Bo

    2018-01-01

    While indirect and direct CP violation (CPV) has been established in the decays of strange and beauty mesons, no CPV has yet been found for baryons. There are different paths to finding CP asymmetry in the decays of strange baryons; they are all highly non-trivial. The HyperCP Collaboration has probed CPV in the decays of single Ξ and Λ [1]. We discuss future lessons from {{{e}}}+{{{e}}}- collisions at BESIII/BEPCII: probing decays of pairs of strange baryons, namely Λ, Σ and Ξ. Realistic goals are to learn about non-perturbative QCD. One can hope to find CPV in the decays of strange baryons; one can also dream of finding the impact of New Dynamics. We point out that an important new era will start with the BESIII/BEPCII data accumulated by the end of 2018. This also supports new ideas to trigger {{J}}/{{\\psi }}\\to \\bar{{{Λ }}}{{Λ }} at the LHCb collaboration. Supported by National Science Foundation (PHY-1520966), National Natural Science Foundation of China (11335009, 11125525), Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (U1532257), the National Key Basic Research Program of China (2015CB856700), Key Research Program of Frontier Sciences, CAS, (QYZDJ-SSW-SLH003), XWK’s work is also supported by MOST (Taiwan) (104-2112-M-001-022)

  19. 'Strange money': risk, finance and socialized debt.

    Science.gov (United States)

    Dodd, Nigel

    2011-03-01

    This paper explores an essential but neglected aspect of recent discussions of the banking and financial system, namely money itself. Specifically, I take up a distinction drawn by Susan Strange which has never been fully elaborated: between a financial system that is global, and an international monetary system that remains largely territorial. I propose a sociological elaboration of this distinction by examining each category, 'finance' and 'money', in terms of its distinctive orientation to risk and debt. Money is distinguished by its high degree of liquidity and low degree of risk, corresponding to expectations that derive from its status as a 'claim upon society'- a form of socialized debt. But as Strange argued, these features of money are being undermined by the proliferation of sophisticated instruments of financial risk management -'strange money'- that, as monetary substitutes, both weaken states' capacity to manage money, and more broadly, contribute to 'overbanking'. The ultimate danger, according to Strange, is the 'death of money'. The paper concludes by exploring the implications of the distinction for sociological arguments about the changing nature of money. © London School of Economics and Political Science 2011.

  20. Strange baryon production in Z hadronic decays

    CERN Document Server

    Abreu, P; Adye, T; Agasi, E; Ajinenko, I; Aleksan, Roy; Alekseev, G D; Allport, P P; Almehed, S; Alvsvaag, S J; Amaldi, Ugo; Amato, S; Andreazza, A; Andrieux, M L; Antilogus, P; Anykeyev, V B; Apel, W D; Arnoud, Y; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barate, R; Bardin, Dimitri Yuri; Barker, G J; Baroncelli, A; Barrio, J A; Bartl, Walter; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Benvenuti, Alberto C; Berggren, M; Bertrand, D; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bloch, D; Blume, M; Blyth, S; Bocci, V; Bolognese, T; Bonesini, M; Bonivento, W; Booth, P S L; Borisov, G; Bosio, C; Bosworth, S; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenner, R A; Bricman, C; Brillault, L; Brown, R C A; Brunet, J M; Brückman, P; Bugge, L; Buran, T; Buys, A; Bärring, O; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Cankocak, K; Cao, F; Carena, F; Carrilho, P; Carroll, L; Caso, Carlo; Cassio, V; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Cerrito, L; Chabaud, V; Charpentier, P; Chaussard, L; Chauveau, J; Checchia, P; Chelkov, G A; Chikilev, O G; Chliapnikov, P V; Chochula, P; Chorowicz, V; Cindro, V; Collins, P; Contreras, J L; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; D'Almagne, B; Da Silva, W; Dahl-Jensen, Erik; Dahm, J; Dam, M; Damgaard, G; Daum, A; Dauncey, P D; Davenport, Martyn; De Angelis, A; De Boeck, H; De Brabandere, S; De Clercq, C; De Lotto, B; De Min, A; De Paula, L S; De Saint-Jean, C; Defoix, C; Della Ricca, G; Delpierre, P A; Demaria, N; Di Ciaccio, Lucia; Dijkstra, H; Djama, F; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Dufour, Y; Dupont, F; Dönszelmann, M; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Ershaidat, N; Erzen, B; Espirito-Santo, M C; Falk, E; Fassouliotis, D; Feindt, Michael; Ferrer, A; Filippas-Tassos, A; Firestone, A; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frenkiel, P; Fries, D E C; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Föth, H; Fürstenau, H; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Gillespie, D; Gokieli, R; Golob, B; Gopal, Gian P; Gorn, L; Gracco, Valerio; Grard, F; Graziani, E; Grosdidier, G; Gunnarsson, P; Guy, J; Guz, Yu; Górski, M; Günther, M; Haedinger, U; Hahn, F; Hahn, M; Hahn, S; Haider, S; Hajduk, Z; Hallgren, A; Hamacher, K; Hao, W; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Higón, E; Hilke, Hans Jürgen; Hill, T S; Holmgren, S O; Holt, P J; Holthuizen, D J; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Ioannou, P; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Joram, Christian; Juillot, P; Jönsson, L B; Jönsson, P E; Kaiser, M; Kalmus, George Ernest; Kapusta, F; Karlsson, M; Karvelas, E; Katsanevas, S; Katsoufis, E C; Keränen, R; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klein, H; Klovning, A; Kluit, P M; Kokkinias, P; Koratzinos, M; Korcyl, K; Kostyukhin, V; Kourkoumelis, C; Kramer, P H; Krammer, Manfred; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Królikowski, J; Kubinec, P; Kucewicz, W; Kurvinen, K L; Kuznetsov, O; Köhne, J H; Köne, B; La Vaissière, C de; Lacasta, C; Laktineh, I; Lamblot, S; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Lapin, V; Last, I; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leitner, R; Lemoigne, Y; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Liko, D; Lindner, R; Lipniacka, A; Lippi, I; Lokajícek, M; Loken, J G; Loukas, D; Lutz, P; Lyons, L; López, J M; López-Aguera, M A; López-Fernandez, A; Lörstad, B; MacNaughton, J N; Maehlum, G; Maio, A; Malychev, V; Mandl, F; Marco, J; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Maron, T; Martí i García, S; Martínez-Rivero, C; Martínez-Vidal, F; Maréchal, B; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; Medbo, J; Meroni, C; Meyer, W T; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Monge, M R; Morettini, P; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Mönig, K; Møller, R; Müller, H; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Negri, P; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nikolaenko, V; Niss, P; Nomerotski, A; Normand, Ainsley; Némécek, S; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Ouraou, A; Paganini, P; Paganoni, M; Pagès, P; Palka, H; Papadopoulou, T D; Pape, L; Parodi, F; Passeri, A; Pegoraro, M; Pennanen, J; Peralta, L; Pernegger, H; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Piana, G; Pierre, F; Pimenta, M; Plaszczynski, S; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Prest, M; Privitera, P; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Renton, P B; Resvanis, L K; Richard, F; Richardson, J; Rinaudo, G; Ripp, I; Romero, A; Roncagliolo, I; Ronchese, P; Roos, L; Rosenberg, E I; Rosso, E; Roudeau, Patrick; Rovelli, T; Ruhlmann-Kleider, V; Ruiz, A; Rídky, J; Rückstuhl, W; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sannino, M; Schneider, H; Schyns, M A E; Sciolla, G; Scuri, F; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Shellard, R C; Siccama, I; Siegrist, P; Simonetti, S; Simonetto, F; Sissakian, A N; Sitár, B; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Squarcia, S; Stanescu, C; Stapnes, Steinar; Stavitski, I; Stepaniak, K; Stichelbaut, F; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Stäck, H; Szczekowski, M; Szeptycka, M; Sánchez, J; Tabarelli de Fatis, T; Tavernet, J P; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Toet, D Z; Tomaradze, A G; Tomé, B; Tortora, L; Tranströmer, G; Treille, D; Trischuk, W; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tuuva, T; Tyapkin, I A; Tyndel, M; Tzamarias, S; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van Doninck, W K; Van Eldik, J; Van der Velde, C; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vlasov, E; Vodopyanov, A S; Voutilainen, M; Vrba, V; Wahlen, H; Walck, C; Waldner, F; Wehr, A; Weierstall, M; Weilhammer, Peter; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Wormser, G; Woschnagg, K; Yip, K; Yu, L; Yushchenko, O P; Zach, F; Zacharatou-Jarlskog, C; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zhigunov, V P; Zimin, N I; Zito, M; Zontar, D; Zuberi, R; Zucchelli, G C; Zumerle, G; de Boer, Wim; van Apeldoorn, G W; van Dam, P; Åsman, B; Österberg, K; Überschär, B; Überschär, S

    1995-01-01

    A study of the production of strange octet and decuplet baryons in hadronic decays of the Z recorded by the DELPHI detector at LEP is presented. This includes the first measurement of the \\Sigma^\\pm average multiplicity. The total and differential cross sections, the event topology and the baryon-antibaryon correlations are compared with current hadronization models.

  1. Strange sea quark effects for low lying baryons

    International Nuclear Information System (INIS)

    Upadhyay, A.; Batra, Meenakshi

    2013-01-01

    Assuming hadrons as an ensemble of quark-gluon Fock states, contributions from sea quarks and gluons can be studied in detail for ground state baryons. Spin crisis of nucleons say that only a small fraction of proton spin is carried by valence quarks. Rest part is distributed among gluons and sea which includes both strange and non-strange quark-anti-quark pairs. This necessitates the study of strange sea quark contribution for other baryons too due to higher mass and presence of strange quark in valence part. Recent studies have also studied strange sea contribution for baryons using different models. We implement the statistical modeling techniques to compute strange sea quark content for baryon octet. Statistical model has already been applied to study sea quark content for nucleons in the form of scalar, vector and tensor sea. In our present work the same idea has been extended for strange sea to probe the structure in more detail. (author)

  2. Strangeness chemical equilibration in a quark-gluon plasma

    International Nuclear Information System (INIS)

    Letessier, Jean; Rafelski, Johann

    2007-01-01

    We study, in the dynamically evolving quark-gluon plasma (QGP) fireball formed in relativistic heavy ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and CERN Large Hadron Collider (LHC), the growth of strangeness yield toward and beyond the chemical equilibrium. We account for the contribution of the direct strangeness production and evaluate the thermal-QCD strangeness production mechanisms. The specific yield of strangeness per entropy, s/S, is the primary target variable. We explore the effect of collision impact parameter, i.e., fireball size, on kinetic strangeness chemical equilibration in QGP. Insights gained in studying the RHIC data with regard to the dynamics of the fireball are applied to the study of strangeness production at the LHC. We use these results and consider the strange hadron relative particle yields at RHIC and LHC in a systematic fashion. We consider both the dependence on s/S and the direct dependence on the participant number

  3. Strange particle correlations measured by the Star experiment in ultra-relativistic heavy ion collisions a RHIC; Etude des correlations de particules etranges mesurees par l'experience STAR dans les collisions d'ions lourds ultra-relativistes au RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Renault, G

    2004-09-01

    Non-identical correlation functions allow to study the space-time evolution of the source of particles formed in ultra-relativistic heavy ion collisions. The STAR experiment is dedicated to probe the formation of a new state of nuclear matter called Quark Gluon Plasma. The proton - lambda correlation function is supposed to be more sensitive to bigger source sizes than the proton - proton because of the absence of the final state Coulomb interaction. In this thesis, proton - lambda, anti-proton - anti-lambda, anti-proton - lambda and proton - anti-lambda correlation functions are studied in Au+Au collisions at {radical}S{sub NN} = 200 GeV using an analytical model. The proton - lambda and anti-proton - anti-lambda correlation functions exhibit the same behavior as in previous measurements. The anti-proton - lambda and proton - anti-lambda correlation functions, measured for the first time, show a very strong signal corresponding to the baryon - anti-baryon annihilation channel. Parameterizing the correlation functions has allowed to characterize final state interactions. (author)

  4. Chemical and dynamics properties of heavy ion collisions at RHIC energies by the measurement of the production of the doubly strange baryons in the STAR experiment; Proprietes chimiques et dynamiques des collisions d'ions lourds aux energies du RHIC par la mesure de la production des baryons doublement etranges dans l'experience STAR

    Energy Technology Data Exchange (ETDEWEB)

    Estienne, M

    2005-04-15

    Lattice QCD calculations predict, at {mu}{sub B} {approx} 0, a crossover from ordinary hadronic matter to a Quark Gluon Plasma. Heavy ion collisions have been proposed to recreate it in the laboratory and to study its properties. The Au+Au, d+Au collisions at {radical}(S{sub NN}) = 200 GeV and the Au+Au ones at 62.4 GeV delivered at RHIC have been probed by the measurement of the {xi} particles in the STAR experiment. Their yield evolution with collision energy and system size gives size to the chemical properties of the reaction in the framework of hadronic and statistical models. The {xi} R{sub CP} shows: (1) a meson/baryon dependence for 2 < {sub pT} < 5 GeV/c well reproduced by quark coalescence and recombination models, (2) the formation of a dense matter signed by a R{sub CP} suppression at {sub pT} > 3 GeV/c, (3) strong interactions between constituents suggesting the existence of strong collectivity in the medium. The {xi} transverse flow seems to be interesting to probe the early stage the collision with presumably partonic degrees of freedom. (author)

  5. Color-flavor locked strange quark matter in a mass density-dependent model

    International Nuclear Information System (INIS)

    Chen Yuede; Wen Xinjian

    2007-01-01

    Properties of color-flavor locked (CFL) strange quark matter have been studied in a mass-density-dependent model, and compared with the results in the conventional bag model. In both models, the CFL phase is more stable than the normal nuclear matter for reasonable parameters. However, the lower density behavior of the sound velocity in this model is completely opposite to that in the bag model, which makes the maximum mass of CFL quark stars in the mass-density-dependent model larger than that in the bag model. (authors)

  6. Strange particles from dense hadronic matter

    International Nuclear Information System (INIS)

    Rafelski, J.; Letessier, J.; Tounsi, A.

    1996-01-01

    After a brief survey of the remarkable accomplishments of the current heavy ion collision experiments up to 200A GeV, we address in depth the role of strange particle production in the search for new phases of matter in these collisions. In particular, we show that the observed enhancement pattern of otherwise rarely produced multistrange antibaryons can be consistently explained assuming color deconfinement in a localized, rapidly disintegrating hadronic source. We develop the theoretical description of this source, and in particular study QCD based processes of strangeness production in the deconfined, thermal quark-gluon plasma phase, allowing for approach to chemical equilibrium and dynamical evolution. We also address thermal charm production. Using a rapid hadronization model we obtain final state particle yields, providing detailed theoretical predictions about strange particle spectra and yields as functions of heavy ion energy. Our presentation is comprehensive and self contained: we introduce the procedures used in data interpretation in considerable detail, discuss the particular importance of selected experimental results, and show how they impact the theoretical developments. (author)

  7. Strange Particle Production from SIS to LHC

    CERN Document Server

    Oeschler, H; Redlich, Krzysztof

    2003-01-01

    A review of meson emission in heavy ion collisions at incident energies from SIS up to collider energies is presented. A statistical model assuming chemical equilibrium and local strangeness conservation (i.e. strangeness conservation per collision) explains most of the observed features. Emphasis is put onto the study of $K^+$ and $K^-$ emission at low incident energies. In the framework of this statistical model it is shown that the experimentally observed equality of $K^+$ and $K^-$ rates at ``threshold-corrected'' energies $\\sqrt{s} - \\sqrt{s_{th}}$ is due to a crossing of two excitation functions. Furthermore, the independence of the $K^+$ to $K^-$ ratio on the number of participating nucleons observed between SIS and RHIC is consistent with this model. It is demonstrated that the $K^-$ production at SIS energies occurs predominantly via strangeness exchange and this channel is approaching chemical equilibrium. The observed maximum in the $K^+/\\pi^+$ excitation function is also seen in the ratio of stran...

  8. Strangeness production in AA and pp collisions

    Energy Technology Data Exchange (ETDEWEB)

    Castorina, Paolo [Universita di Catania, Dipartimento di Fisica ed Astronomia, Catania (Italy); INFN, Catania (Italy); Satz, Helmut [Universitaet Bielefeld, Fakultaet fuer Physik, Bielefeld (Germany)

    2016-07-15

    Boost-invariant hadron production in high-energy collisions occurs in causally disconnected regions of finite space-time size. As a result, globally conserved quantum numbers (charge, strangeness, baryon number) are conserved locally in spatially restricted correlation clusters. Their size is determined by two time scales: the equilibration time specifying the formation of a quark-gluon plasma, and the hadronization time, specifying the onset of confinement. The expected values for these scales provide the theoretical basis for the suppression observed for strangeness production in elementary interactions (pp, e{sup +}e{sup -}) below LHC energies. In contrast, the space-time superposition of individual collisions in high-energy heavy-ion interactions leads to higher energy densities, resulting in much later hadronization and hence much larger hadronization volumes. This largely removes the causality constraints and results in an ideal hadronic resonance gas in full chemical equilibrium. In the present paper, we determine the collision energies needed for that; we also estimate when pp collisions reach comparable hadronization volumes and thus determine when strangeness suppression should disappear there as well. (orig.)

  9. Complete strangeness measurements in heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Tomasik, Boris [Univerzita Mateja Bela, FPV, Banska Bystrica (Slovakia); Czech Technical University in Prague, FNSPE, Prague 1 (Czech Republic); Kolomeitsev, Evgeni E. [Univerzita Mateja Bela, FPV, Banska Bystrica (Slovakia)

    2016-08-15

    We discuss strangeness production in heavy-ion collisions within and around the energy range of the planned NICA facility. We describe a minimal statistical model, in which the total strangeness yield is fixed by the observed or calculated K{sup +} multiplicity. We show how the exact strangeness conservation can be taken into account on event-by-event basis in such a model. We argue that from strange particle yields one can reveal information about the collision dynamics and about possible modifications of particle properties in medium. This can be best achieved if the complete strangeness measurement is performed, i.e. kaons, antikaons, hyperons and multistrange hyperons are registered in the same experimental setup. In particular, production of hadrons containing two and more strange quarks, like Ξ and Ω baryons could be of interest. (orig.)

  10. Experimental overview and challenge in strangeness nuclear physics — strangeness in the past and coming decades

    International Nuclear Information System (INIS)

    Imai, Kenichi

    2010-01-01

    A great progress has been made in strangeness nuclear physics in the past decade. Examples are; 1) The "hyperfine" structure of hypernuclei were measured with the Hyperball, and ΛN spin dependent interactions in p-shell hypernuclei were determined. 2) The "complete measurements" of the weak decay of hypernuclei were made and the np ratio puzzle in the non-mesonic decay was solved. 3) The discovery of a clean event of "Lambpha" and determination of its binding energy concluded that the Λ-Λ interaction is weak attractive. However, we still have important questions to be answered in this field, especially in relation with QCD and nuclear physics. For the future strangeness nuclear physics, we have and will have facilities such as JLab, SPring-8, Daphne, J-PARC, FAIR. We discuss experimental challenges in the strangeness nuclear physics and related fields in the next decade. (author)

  11. Strangeness suppression in e+e- light flavour jets

    International Nuclear Information System (INIS)

    Liu Ximing; Sun Xubin

    2007-01-01

    From the simple physical picture of quark combination model, the authors obtain the generate probabilities of various particles and relative ration in e + e - →q 0 (q 0 )-bar→h's process, and find that the relationship between the ration of strange hadron to unstrange hadron γ and the strangeness suppression factor λ. Our results can be used to explain particle ration enhancement observed in experiments without assumption of strangeness suppression factor enhancement. (authors)

  12. Form factors and other measures of strangeness in the nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Feldmann, T. [Siegen Univ. (Germany). Theoretische Physik I; Kroll, P. [Bergische Univ., Wuppertal (Germany). Fachbereich Physik

    2007-11-15

    We discuss the phenomenology of strange-quark dynamics in the nucleon, based on experimental and theoretical results for electroweak form factors and for parton densities. In particular, we construct a model for the generalized parton distribution that relates the asymmetry s(x)- anti s(x) between the longitudinal momentum distributions of strange quarks and antiquarks with the form factor F{sup s}{sub 1}(t), which describes the distribution of strangeness in transverse position space. (orig.)

  13. Form factors and other measures of strangeness in the nucleon

    International Nuclear Information System (INIS)

    Diehl, M.; Feldmann, T.; Kroll, P.

    2007-11-01

    We discuss the phenomenology of strange-quark dynamics in the nucleon, based on experimental and theoretical results for electroweak form factors and for parton densities. In particular, we construct a model for the generalized parton distribution that relates the asymmetry s(x)- anti s(x) between the longitudinal momentum distributions of strange quarks and antiquarks with the form factor F s 1 (t), which describes the distribution of strangeness in transverse position space. (orig.)

  14. Use of Added Sugars Instead of Total Sugars May Improve the Capacity of the Health Star Rating System to Discriminate between Core and Discretionary Foods.

    Science.gov (United States)

    Menday, Hannah; Neal, Bruce; Wu, Jason H Y; Crino, Michelle; Baines, Surinder; Petersen, Kristina S

    2017-12-01

    The Australian Government has introduced a voluntary front-of-package labeling system that includes total sugar in the calculation. Our aim was to determine the effect of substituting added sugars for total sugars when calculating Health Star Ratings (HSR) and identify whether use of added sugars improves the capacity to distinguish between core and discretionary food products. This study included packaged food and beverage products available in Australian supermarkets (n=3,610). The product categories included in the analyses were breakfast cereals (n=513), fruit (n=571), milk (n=309), non-alcoholic beverages (n=1,040), vegetables (n=787), and yogurt (n=390). Added sugar values were estimated for each product using a validated method. HSRs were then estimated for every product according to the established method using total sugar, and then by substituting added sugar for total sugar. The scoring system was not modified when added sugar was used in place of total sugar in the HSR calculation. Products were classified as core or discretionary based on the Australian Dietary Guidelines. To investigate whether use of added sugar in the HSR algorithm improved the distinction between core and discretionary products as defined by the Australian Dietary Guidelines, the proportion of core products that received an HSR of ≥3.5 stars and the proportion of discretionary products that received an HSR of added sugars were determined. There were 2,263 core and 1,347 discretionary foods; 1,684 of 3,610 (47%) products contained added sugar (median 8.4 g/100 g, interquartile range=5.0 to 12.2 g). When the HSR was calculated with added sugar instead of total sugar, an additional 166 (7.3%) core products received an HSR of ≥3.5 stars and 103 (7.6%) discretionary products received a rating of ≥3.5 stars. The odds of correctly identifying a product as core vs discretionary were increased by 61% (odds ratio 1.61, 95% CI 1.26 to 2.06; Padded compared to total sugars. In the six

  15. Production rates of strange vector mesons at the Z0 resonance

    Energy Technology Data Exchange (ETDEWEB)

    Dima, Mihai O. [Stanford Univ., CA (United States)

    1997-05-01

    This dissertation presents a study of strange vector meson production, "leading particle" effect and a first direct measurement of the strangeness suppression parameter in hadronic decays of the neutral electroweak boson, Z. The measurements were performed in e+e- collisions at the Stanford Linear Accelerator Center (SLAC) with the SLC Large Detector (SLD) experiment. A new generation particle ID system, the SLD Cerenkov Ring Imaging Detector (CRID) is used to discriminate kaons from pions, enabling the reconstruction of the vector mesons over a wide momentum range. The inclusive production rates of ρ and K*0 and the differential rates versus momentum were measured and are compared with those of other experiments and theoretical predictions. The high longitudinal polarisation of the SLC electron beam is used in conjunction with the electroweak quark production asymmetries to separate quark jets from antiquark jets. K*0 production is studied separately in these samples, and the results show evidence for the "leading particle" effect. The difference between K*0 production rates at high momentum in quark and antiquark jets yields a first direct measurement of strangeness suppression in jet fragmentation.

  16. Production rates of strange vector mesons at the Z0 resonance

    International Nuclear Information System (INIS)

    Dima, M.O.

    1997-05-01

    This dissertation presents a study of strange vector meson production, open-quotes leading particleclose quotes effect and a first direct measurement of the strangeness suppression parameter in hadronic decays of the neutral electroweak boson, Z 0 . The measurements were performed in e + e - collisions at the Stanford Linear Accelerator Center (SLAC) with the SLC Large Detector (SLD) experiment. A new generation particle ID system, the SLD Cerenkov Ring Imaging Detector (CRID) is used to discriminate kaons from pions, enabling the reconstruction of the vector mesons over a wide momentum range. The inclusive production rates of φ and K* 0 and the differential rates versus momentum were measured and are compared with those of other experiments and theoretical predictions. The high longitudinal polarisation of the SLC electron beam is used in conjunction with the electroweak quark production asymmetries to separate quark jets from antiquark jets. K* 0 production is studied separately in these samples, and the results show evidence for the open-quotes leading particleclose quotes effect. The difference between K* 0 production rates at high momentum in quark and antiquark jets yields a first direct measurement of strangeness suppression in jet fragmentation

  17. Strange quark content in the nucleon and the strange quark vector current form factors

    International Nuclear Information System (INIS)

    Dubnicka, S.; Dubnickova, A.Z.

    1996-12-01

    A behaviour of the form factors of the nucleon matrix element of the strange quark vector current in the momentum range of the planned measurements in MIT/Bates and CEBAF is predicted theoretically without using any of the experimental information on the nucleon electromagnetic structure. The corresponding leading nonvanishing moments of the nucleon vector strangeness distribution are comparable with the values obtained by other authors in the framework of the method based on the vector meson pole fit of the isoscalar electromagnetic form factors of the nucleon. (author). 16 refs, 2 figs

  18. Space-Time Geometry of Quark and Strange Quark Matter

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We study quark and strange quark matter in the context of general relativity. For this purpose, we solve Einstein's field equations for quark and strange quark matter in spherical symmetric space-times. We analyze strange quark matter for the different equations of state (EOS) in the spherical symmetric space-times, thus we are able to obtain the space-time geometries of quark and strange quark matter. Also, we discuss die features of the obtained solutions. The obtained solutions are consistent with the results of Brookhaven Laboratory, i.e. the quark-gluon plasma has a vanishing shear (i.e. quark-gluon plasma is perfect).

  19. Production of strange clusters in relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Dover, C.B.; Baltz, A.J.; Pang, Yang; Schlagel, T.J.; Kahana, S.H.

    1993-02-01

    We address a number of issues related to the production of strangeness in high energy heavy ion collisions, including the possibility that stable states of multi-strange hyperonic or quark matter might exist, and the prospects that such objects may be created and detected in the laboratory. We make use of events generated by the cascade code ARC to estimate the rapidity distribution dN/dy of strange clusters produced in Si+Au and Au+Au collisions at AGS energies. These calculations are performed in a simple coalescence model, which yields a consistent description of the strange cluster (d, 3 HE, 3 H, 4 He) production at these energies. If a doubly strange, weakly bound ΛΛ dibaryon exists, we find that it is produced rather copiously in Au+Au collisions, with dN/dy ∼0.1 at raid-rapidity. If one adds another non-strange or strange baryon to a cluster, the production rate decreases by roughly one or two orders of magnitude, respectively. For instance, we predict that the hypernucleus ΛΛ 6 He should have dN/dy ∼5 x 10 -6 for Au+Au central collisions. It should be possible to measure the successive Λ → pπ- weak decays of this object. We comment on the possibility that conventional multi-strange hypernuclei may serve as ''doorway states'' for the production of stable configurations of strange quark matter, if such states exist

  20. Strange and Multi-strange Particle Production in pPb and PbPb with CMS

    CERN Document Server

    Ni, Hong

    2017-01-01

    Identified particle spectra provide an important tool for understanding the particle production mechanism and the dynamical evolution of the medium created in relativistic heavy ion collisions. Studies involving strange and multi-strange hadrons, such as $K^0_S$, $\\Lambda$, and $\\Xi^-$, carry additional information since there is no net strangeness content in the initial colliding system. Strangeness enhancement in AA collisions with respect to pp and pA collisions has long been considered as one of the signatures for quark-gluon plasma (QGP) formation. Recent observations of collective effects in high-multiplicity pp and pA collisions raise the question of whether QGP can also be formed in the smaller systems. Systematic studies of strange particle abundance, particle ratios, and nuclear modification factors can shed light on this issue. The CMS experiment has excellent strange-particle reconstruction capabilities over a broad kinematic range, and dedicated high-multiplicity triggers in pp and pPb collision...

  1. Structural Discrimination

    DEFF Research Database (Denmark)

    Thorsen, Mira Skadegård

    discrimination as two ways of articulating particular, opaque forms of racial discrimination that occur in everyday Danish (and other) contexts, and have therefore become normalized. I present and discuss discrimination as it surfaces in data from my empirical studies of discrimination in Danish contexts...

  2. On Surface Tension for Compact Stars R. Sharma & S. D. Maharaj

    Indian Academy of Sciences (India)

    Abstract. In an earlier analysis it was demonstrated that general rel- ativity gives higher values of surface tension in strange stars with quark matter than neutron stars.We generate the modified Tolman–Oppenheimer–. Volkoff equation to incorporate anisotropic matter and use this to show that pressure anisotropy provides ...

  3. Calculation of baryon chemical potential and strangeness chemical potential in resonance matter

    International Nuclear Information System (INIS)

    Fu Yuanyong; Hu Shouyang; Lu Zhongdao

    2006-01-01

    Based on the high energy heavy-ion collisions statistical model, the baryon chemical potential and strangeness chemical potential are calculated for resonance matter with net baryon density and net strangeness density under given temperature. Furthermore, the relationship between net baryon density, net strangeness density and baryon chemical potential, strangeness chemical potential are analyzed. The results show that baryon chemical potential and strangeness chemical potential increase with net baryon density and net strangeness density increasing, the change of net baryon density affects baryon chemical potential and strangeness chemical potential more strongly than the change of net strangeness density. (authors)

  4. Strangeness condensation and ''clearing'' of the vacuum

    International Nuclear Information System (INIS)

    Brown, G.E.; Kubodera, Kuniharu; Rho, M.; State Univ. of New York, Stony Brook

    1987-01-01

    We show that a substantial amount of strange quark-antiquark pair condensates in the nucleon required by the πN sigma term implies that kaons could condense in nuclear matter at a density about three times that of normal nuclear matter. This phenomenon can be understood as the ''cleansing'' of qanti q condensates from the QCD vacuum by a dense nuclear matter, resulting in a (partial) restoration of the chiral symmetry explicitly broken in the vacuum. It is suggested that the condensation signals a new phase distinct from that of quark plasma and that of ordinary dense hadronic matter. (orig.)

  5. Quark-gluon plasma, and strangeness

    International Nuclear Information System (INIS)

    Rafelski, Johann; Letessier, Jean

    2002-01-01

    In order to recognize the new form of matter created at RHIC and SPS as the deconfined quark-gluon plasma state (QGP), we need to understand the expected properties of this phase near to the conditions of its formation and disintegration. Thus, we first develop a model of QGP considering the constrains arising from QCD properties and lattice results, and explore its properties. In the second part, we describe the kinetic theory of strangeness production in the QGP phase. We show that gluon fusion dominate and evaluate the degree of equilibration expected at RHIC

  6. Strange bedfellows: Cervantes and Mary Wollstonecraft Shelley

    Directory of Open Access Journals (Sweden)

    Alfredo Moro

    2017-11-01

    Full Text Available Miguel de Cervantes and Mary Shelley do seem, at first sight, two strange bedfellows. Notwithstanding the evident differences between the narrative of both authors, the English novelist showed a notable interest for the life and works of Miguel de Cervantes throughout her literary career. This article intends to offer a precise portrait of the Cervantean interests of the author of Frankenstein, tracing these through her personal correspondence, her narrative production, and finally, through her contribution to the realm of Cervantean studies: Shelley’s Life of Cervantes (1837, published in Dyonisius Lardner’s Cabinet Cyclopaedia.

  7. STRANGE BARYONIC MATTER AND KAON CONDENSATION

    Czech Academy of Sciences Publication Activity Database

    Gazda, Daniel; Friedman, E.; Gal, A.; Mareš, Jiří

    2011-01-01

    Roč. 26, 3-4 (2011), s. 567-569 ISSN 0217-751X. [11th International Workshop on Meson Production, Properties and Interaction. Krakow, 10.06.2010-15.06.2010] R&D Projects: GA ČR GA202/09/1441 Institutional research plan: CEZ:AV0Z10480505 Keywords : (K)over-bar-nuclear bound states * strange baryonic matter * kaon condensation Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.053, year: 2011

  8. Strange Curves, Counting Rabbits, & Other Mathematical Explorations

    CERN Document Server

    Ball, Keith

    2011-01-01

    How does mathematics enable us to send pictures from space back to Earth? Where does the bell-shaped curve come from? Why do you need only 23 people in a room for a 50/50 chance of two of them sharing the same birthday? In Strange Curves, Counting Rabbits, and Other Mathematical Explorations, Keith Ball highlights how ideas, mostly from pure math, can answer these questions and many more. Drawing on areas of mathematics from probability theory, number theory, and geometry, he explores a wide range of concepts, some more light-hearted, others central to the development of the field and used dai

  9. Strange Quark Matter Status and Prospects

    Science.gov (United States)

    Sandweiss, J.

    2004-01-01

    The existence of quark states with more than three quarks is allowed in QCD. The stability of such quark matter states has been studied with lattice QCD and phenomenological bag models, but is not well constrained by theory. The addition of strange quarks to the system allows the quarks to be in lower energy states despite the additional mass penalty. There is additional stability from reduced Coulomb repulsion. SQM is expected to have a low Z/A. Stable or metastable massive multiquark states contain u, d, and s quarks.

  10. Results from CERN experiment NA36 on strangeness production

    International Nuclear Information System (INIS)

    1991-12-01

    Measurements of the production of strange particles in the reactions S + Pb and S + S at beam momentum 200GeV/c per nucleon are presented. A short description of CERN experiment NA36 and the methods of raw data analysis, is followed by physics results concentrating on the dependence of strange particle production on multiplicity. Transverse momentum distributions are also presented

  11. Examination of the strangeness contribution to the nucleon magnetic moment

    NARCIS (Netherlands)

    Chen, XS; Timmermans, RGE; Sun, WM; Zong, HS; Wang, F

    We examine the nucleon strangeness magnetic moment mu(s) with a lowest order meson cloud model. We observe that (1) strangeness in the nucleon is a natural requirement of the empirical relation mu(p)/mu(n)similar or equal to-3/2, which favors an SU(3) octet meson cloud instead of merely the SU(2)

  12. The Geometric Structure of Strange Attractors in the Lozi Map

    Institute of Scientific and Technical Information of China (English)

    YongluoCAO; ZengrongLIU

    1998-01-01

    In this paper,the structure of the strange attractors in the Lozi map is investigated on basis of the results gotten by the authors in 1991-1993,The new results of the strange atrtractors of the Lozi map show that our viewpoint is correct.

  13. Strangeness and quark gluon plasma: Aspects of theory and experiment

    International Nuclear Information System (INIS)

    Eggers, H.C.; Rafelski, J.

    1990-07-01

    A survey of our current understanding of the strange particle signature of quark gluon plasma is presented. Emphasis is placed on the theory of strangeness production in the plasma and recent pertinent experimental results. Useful results on spectra of thermal particles are given. (orig.)

  14. Strangeness and charm production in high energy heavy ion collisions

    International Nuclear Information System (INIS)

    Xu, Nu

    2001-01-01

    We discuss the dynamical effects of strangeness and charm production in high energy nuclear collisions. In order to understand the early stage dynamical evolution, it is necessary to study the transverse momentum distributions of multi-strange hadrons like Ξ and Ω and charm mesons like J/Ψ as a function of collision centrality

  15. Mini-Proceedings of ECT Workshop Strangeness in Nuclei

    CERN Document Server

    Zmeskal, J

    2011-01-01

    This workshop brought together international experts in the research area of strangeness in nuclei physics, working on theory as well as on experiments, to discuss the present status, to develop new methods of analysis and to have the opportunity for brainstorming towards future studies, going towards a deeper understanding of the hot topics in the low-energy QCD in the strangeness sector.

  16. Symbiotic stars

    International Nuclear Information System (INIS)

    Boyarchuk, A.A.

    1975-01-01

    There are some arguments that the symbiotic stars are binary, where one component is a red giant and the other component is a small hot star which is exciting a nebula. The symbiotic stars belong to the old disc population. Probably, symbiotic stars are just such an evolutionary stage for double stars as planetary nebulae for single stars. (Auth.)

  17. Strangeness in the nucleon on the light-cone

    International Nuclear Information System (INIS)

    Malheiro, Manuel; Melnitchouk, Wally

    1999-01-01

    Strange matrix elements of the nucleon are calculated within the light-cone formulation of the meson cloud model. The Q 2 dependence of the strange vector form factors is computed, and the strangeness radius and magnetic moment extracted, both of which are found to be very small. The strange magnetic moment μ S is seen to change sign once the spurious form factors arising from the violation of rotational invariance are subtracted. The resulting μ S is small and slightly positive, in agreement with the trend of the recent data from the SAMPLE experiment. Within the same framework one finds a small but non-zero excess of the antistrange distribution over the strange at large x. (author)

  18. Rapidity dependence of strangeness enhancement factor at FAIR energies

    International Nuclear Information System (INIS)

    Dey, Kalyan; Bhattacharjee, B.

    2014-01-01

    Strange particles are produced only at the time of collisions and thus expected to carry important information of collision dynamics. Strangeness enhancement is considered to be one of the traditional signatures of formation of Quark Gluon Plasma (QGP). Due to the limitation of the detector acceptance, the past and ongoing heavy ion experiments could measure the strangeness enhancement at midrapidity only. But the future heavy ion experiment CBM at FAIR will have the access to the entire forward rapidity hemisphere and thus the experimental determination of rapidity dependent strangeness enhancement is a possibility. In this work, an attempt has therefore been made to study the rapidity dependent strangeness enhancement at FAIR energies with the help of a string based hadronic model (UrQMD). A sum of 93 million minimum biased UrQMD events have been used for the present analysis

  19. Strange Particles and Heavy Ion Physics

    Energy Technology Data Exchange (ETDEWEB)

    Bassalleck, Bernd [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Physics and Astronomy; Fields, Douglas [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Physics and Astronomy

    2016-04-28

    This very long-running grant has supported many experiments in nuclear and particle physics by a group from the University of New Mexico. The gamut of these experiments runs from many aspects of Strangeness Nuclear Physics, to rare Kaon decays, to searches for exotic Hadrons such as Pentaquark or H-Dibaryon, and finally to Spin Physics within the PHENIX collaboration at RHIC. These experiments were performed at a number of laboratories worldwide: first and foremost at Brookhaven National Lab (BNL), but also at CERN, KEK, and most recently at J-PARC. In this Final Technical Report we summarize progress and achievements for this award since our last Progress Report, i.e. for the period of fall 2013 until the award’s termination on November 30, 2015. The report consists of two parts, representing our two most recent experimental efforts, participation in the Nucleon Spin Physics program of the PHENIX experiment at RHIC, the Relativistic Heavy Ion Collider at BNL – Task 1, led by Douglas Fields; and participation in several Strangeness Nuclear Physics experiments at J-PARC, the Japan Proton Accelerator Research Center in Tokai-mura, Japan – Task 2, led by Bernd Bassalleck.

  20. Halo structure of strange particles in nuclei

    International Nuclear Information System (INIS)

    Akaishi, Yoshinori; Yamazaki, Toshimitsu.

    1997-01-01

    Some characteristic behaviors of hyperons in nuclei which have recently been revealed experimentally and theoretically are discussed with the emphasis on the repulsive part of the hyperon-nucleus interaction. The observed Σ 4 He nucleus is a bound state with J π = 0 + and T ≅ 1/2. Its nucleus-Σ potential derived from a realistic ΣN interaction is characterized by inner repulsion and a strong Lane term, which play important roles in forming the Σ-hypernuclear bound state. In 208 Pb a typical Coulomb-assisted bound state is expected, where Σ is trapped in the surface region by the nucleus-Σ potential with the aid of Coulomb and centrifugal interactions. In the double-strangeness (S=-2) sector, there is a possibility that the lightest double-Λ hypernucleus ΛΛ 4 H is abundantly populated by stopping Ξ - on 4 He. Its formation branching amounts to about 15%. A stopped Ξ - on 9 Be will also produce efficiently a variety of double-Λ hyperfragments. Discrete spectra of weak-decay pions from the fragments will provide a means of mass spectroscopy of double-Λ hypernuclei. In the S=-2 five-body system an excited state Ξ 5 H is predicted to appear with 'strangeness halo' and the ground state ΛΛ 5 H with almost pure ΛΛ component. (author)

  1. Notes on properties of holographic strange metals

    International Nuclear Information System (INIS)

    Lee, Bum-Hoon; Pang, Da-Wei

    2010-01-01

    We investigate properties of holographic strange metals in p+2 dimensions, generalizing the analysis performed in [S. A. Hartnoll et al. J. High Energy Phys. 04 (2010) 120]. The bulk spacetime is a p+2-dimensional Lifshitz black hole, while the role of charge carriers is played by probe D-branes. We mainly focus on massless charge carriers, where most of the results can be obtained analytically. We obtain exact results for the free energy and calculate the entropy density and the heat capacity, as well as the speed of sound at low temperature. We obtain the DC conductivity and DC Hall conductivity and find that the DC conductivity takes a universal form in the large density limit, while the Hall conductivity is also universal in all dimensions. We also study the resistivity in different limits and clarify the condition for the linear dependence on the temperature, which is a key feature of strange metals. We show that our results for the DC conductivity are consistent with those obtained via the Kubo formula and we obtain the charge diffusion constant analytically. The corresponding properties of massive charge carriers are also discussed in brief.

  2. Double Degenerate Stars

    International Nuclear Information System (INIS)

    Xin-Lian, Luo; Hua, Bai; Lei, Zhao

    2008-01-01

    Regardless of the formation mechanism, an exotic object, the double degenerate star (DDS), is introduced and investigated, which is composed of baryonic matter and some unknown fermion dark matter. Different from the simple white dwarfs (WDs), there is additional gravitational force provided by the unknown fermion component inside DDSs, which may strongly affect the structure and the stability of such kind of objects. Many possible and strange observational phenomena connecting with them are concisely discussed. Similar to the normal WD, this object can also experience thermonuclear explosion as type Ia supernova explosion when DDS's mass exceeds the maximum mass that can be supported by electron degeneracy pressure. However, since the total mass of baryonic matter can be much lower than that of WD at Chandrasekhar mass limit, the peak luminosity should be much dimmer than what we expect before, which may throw a slight shadow on the standard candle of SN Ia in the research of cosmology. (general)

  3. Measurement of the Strange Spectral Function in Hadronic $\\tau$ Decays

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Amaral, P.; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Buesser, K.; Burckhart, H.J.; Campana, S.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krieger, P.; von Krogh, J.; Kruger, K.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Layter, J.G.; Lellouch, D.; Lettso, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Masetti, G.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Menke, S.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Moed, S.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rosati, S.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, Matthias; Schumacher, M.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2004-01-01

    Tau Lepton decays with open strangeness in the final state are measured with the OPAL detector at LEP to determine the strange hadronic spectral function of the tau lepton. The decays tau- -> (Kpi)-nu tau, (Kpipi)-nu tau and (Kpipipi)-nu tau with final states consisting of neutral and charged kaons and pions have been studied. The invariant mass distributions of 93.4% of these final states have been experimentally determined. Monte Carlo simulations have been used for the remaining 6.6% and for the strange final states including eta mesons. The reconstructed strange final states, corrected for resolution effects and detection efficiencies, yield the strange spectral function of the tau lepton. The moments of the spectral function and the ratio of strange to non-strange moments, which are important input parameters for theoretical analyses, are determined. Furthermore, the branching fractions B(tau- -> K-pi0nu tau) = (0.471+-0.059stat+-0.023sys)% and B(tau- -> K-pi+pi-nu tau) = (0.415+-0.053stat+-0.040sys)% ha...

  4. Strange-face illusions during inter-subjective gazing.

    Science.gov (United States)

    Caputo, Giovanni B

    2013-03-01

    In normal observers, gazing at one's own face in the mirror for a few minutes, at a low illumination level, triggers the perception of strange faces, a new visual illusion that has been named 'strange-face in the mirror'. Individuals see huge distortions of their own faces, but they often see monstrous beings, archetypal faces, faces of relatives and deceased, and animals. In the experiment described here, strange-face illusions were perceived when two individuals, in a dimly lit room, gazed at each other in the face. Inter-subjective gazing compared to mirror-gazing produced a higher number of different strange-faces. Inter-subjective strange-face illusions were always dissociative of the subject's self and supported moderate feeling of their reality, indicating a temporary lost of self-agency. Unconscious synchronization of event-related responses to illusions was found between members in some pairs. Synchrony of illusions may indicate that unconscious response-coordination is caused by the illusion-conjunction of crossed dissociative strange-faces, which are perceived as projections into each other's visual face of reciprocal embodied representations within the pair. Inter-subjective strange-face illusions may be explained by the subject's embodied representations (somaesthetic, kinaesthetic and motor facial pattern) and the other's visual face binding. Unconscious facial mimicry may promote inter-subjective illusion-conjunction, then unconscious joint-action and response-coordination. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Differential discriminator

    International Nuclear Information System (INIS)

    Dukhanov, V.I.; Mazurov, I.B.

    1981-01-01

    A principal flowsheet of a differential discriminator intended for operation in a spectrometric circuit with statistical time distribution of pulses is described. The differential discriminator includes four integrated discriminators and a channel of piled-up signal rejection. The presence of the rejection channel enables the discriminator to operate effectively at loads of 14x10 3 pulse/s. The temperature instability of the discrimination thresholds equals 250 μV/ 0 C. The discrimination level changes within 0.1-5 V, the level shift constitutes 0.5% for the filling ratio of 1:10. The rejection coefficient is not less than 90%. Alpha spectrum of the 228 Th source is presented to evaluate the discriminator operation with the rejector. The rejector provides 50 ns time resolution

  6. Pulsations of the R Coronae Borealis stars

    International Nuclear Information System (INIS)

    Cox, J.P.; King, D.S.; Cox, A.N.; Wheeler, J.C.; Hansen, C.J.; Hodson, S.W.

    1980-01-01

    The radial pulsations of very luminous, low-mass models (L/M approx. 10 4 , solar units), which are possible representatives of the R CrB stars, have been examined. These pulsations are extremely nonadiabatic. There are in some cases at least one extra (strange) mode which makes interpretation difficult. The blue instability edges are also peculiar, in that there is an abrupt excursion of the blue edge to the blue for L/M sufficiently large. The range of periods of the model encompasses observed periods of the Cepheid-like pulsations of actual R CrB stars

  7. Status and prospects for strange physics at LHCb

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    Rare decays are fundamental probes of physics beyond the Standard Model. We present the current status of rare decays studies at the LHCb experiment and discuss a possible picture emerging from these measurements. The expanding LHCb program of strange physics, in particular of their rare decays, provides a unique and complementary probe to test the SM with respect to the beauty and charm. We present recent results on rare strange hadrons decays exploiting the LHCb Run I data. We then present prospects for strange physics with the LHCb Run II data and after the improvements in the trigger for the LHCb Upgrade.

  8. Quark Matter May Not Be Strange.

    Science.gov (United States)

    Holdom, Bob; Ren, Jing; Zhang, Chen

    2018-06-01

    If quark matter is energetically favored over nuclear matter at zero temperature and pressure, then it has long been expected to take the form of strange quark matter (SQM), with comparable amounts of u, d, and s quarks. The possibility of quark matter with only u and d quarks (udQM) is usually dismissed because of the observed stability of ordinary nuclei. However, we find that udQM generally has lower bulk energy per baryon than normal nuclei and SQM. This emerges in a phenomenological model that describes the spectra of the lightest pseudoscalar and scalar meson nonets. Taking into account the finite size effects, udQM can be the ground state of baryonic matter only for baryon number A>A_{min} with A_{min}≳300. This ensures the stability of ordinary nuclei and points to a new form of stable matter just beyond the periodic table.

  9. Strange particle production from quark matter droplets

    International Nuclear Information System (INIS)

    Werner, K.; Hladik, M.

    1995-01-01

    We recently introduced new methods to study ultrarelativistic nuclear scattering by providing a link between the string model approach and a thermal description. The string model is used to provide information about fluctuations in energy density. Regions of high energy density are considered to be quark matter droplets and treated macroscopically. At SPS energies, we find mainly medium size droplets---with energies up to few tens of Gev. A key issue is the microcanonical treatment of individual quark matter droplets. Each droplet hadronizes instantaneously according to the available n-body phase space. Due to the huge number of possible hadron configurations, special Monte Carlo techniques have been developed to calculate this disintegration. We present results concerning the production of strange particles from such a hadronization as compared to string decay. copyright 1995 American Institute of Physics

  10. Chiral symmetry and strangeness at SIS energies

    International Nuclear Information System (INIS)

    Lutz, M.F.M.

    2003-11-01

    In this talk we review the consequences of the chiral SU(3) symmetry for strangeness propagation in nuclear matter. Objects of crucial importance are the meson-baryon scattering amplitudes obtained within the chiral coupled-channel effective field theory. Results for antikaon and hyperon-resonance spectral functions in cold nuclear matter are presented and discussed. The importance of the Σ(1385) resonance for the subthreshold antikaon production in heavy-ion reaction at SIS is pointed out. The in-medium properties of the latter together with an antikaon spectral function based on chiral SU(3) dynamics suggest a significant enhancement of the π Λ → anti Κ N reaction in nuclear matter. (orig.)

  11. The Universe is a Strange Place

    Science.gov (United States)

    Wilczek, Frank

    2006-01-01

    Our understanding of ordinary matter is remarkably accurate and complete, but it is based on principles that are very strange and unfamiliar. As I'll explain, we've come to understand matter to be a Music of the Void, in a remarkably literal sense. Just as we physicists finalized that wonderful understanding, towards the end of the twentieth century, astronomers gave us back our humility, by informing us that ordinary matter - what we, and chemists and biologists, and astronomers themselves, have been studying all these centuries constitutes only about 5% of the mass of the universe as a whole. I'll describe some of our promising attempts to rise to this challenge by improving, rather than merely complicating, our description of the world.

  12. Strangeness photoproduction with the SAPHIR-detector

    International Nuclear Information System (INIS)

    Merkel, H.

    1993-12-01

    At the ELSA facility at Bonn a photon beam with a high duty cycle up to energies of 3.3 GeV is available. In this energy range the large solid angle detector SAPHIR enables us to investigate the strangeness photoproduction starting from threshold. SAPHIR has already achieved results for the reactions γ+p→K + +Λ and γ+p→K + +Σ 0 . This work investigates the possibilities to measure the related reactions γ+n→K 0 +Λ and γ+n→K 0 +Σ 0 at a deuteron target and to measure the reaction γ+p→K 0 +Σ + at a proton target. For the first time the Σ + polarisation has been measured. With an cross section 10 times smaller compared to the kaon hyperon reactions, the photoproduction of the Φ(1020) meson can be investigated with the SAPHIR detector too. First reconstructed events are shown. (orig.)

  13. Evolution of newborn neutron stars: role of quark matter nucleation

    International Nuclear Information System (INIS)

    Bombaci, Ignazio; Logoteta, Domenico; Providencia, Constança; Vidaña, Isaac

    2011-01-01

    A phase of strong interacting matter with deconfined quarks is expected in the core of massive neutron stars. We study the quark deconfinement phase transition in cold (T = 0) and hot β-stable hadronic matter. Assuming a first order phase transition, we calculate and compare the nucleation rate and the nucleation time due to thermal and quantum nucleation mechanisms. We show that above a threshold value of the central pressure a pure hadronic star (HS) is metastable to the conversion to a quark star (QS) (i.e. hybrid star or strange star). We introduce the concept of critical mass M cr for cold HSs and proto-hadronic stars (PHSs), and the concept of limiting conversion temperature for PHSs. We show that PHSs with a mass M cr could survive the early stages of their evolution without decaying to QSs. Finally, we discuss the possible evolutionary paths of proto-hadronic stars.

  14. Strangeness in hot and dense nuclear matter

    International Nuclear Information System (INIS)

    Nappi, E.

    2009-01-01

    Ultra-relativistic heavy-ion collisions are believed to provide the extreme conditions of energy densities able to lead to a transition to a short-lived state, called Quark-Gluon Plasma (QGP), where the quarks are no longer bound inside hadrons. The studies performed so far, formerly at SPS (CERN) and later at RHIC (BNL) allowed to achieve a multitude of crucial results consistent with the hypothesis that a new phase of the QCD matter has been indeed created. However, the emerging picture is that of the formation of a strongly interacting medium with negligibly small viscosity, a perfect liquid, rather than the ideal perturbative QCD parton-gas predicted by most theorists. The head-on collision between lead nuclei at the unprecedented energies of the forthcoming Large Hadron Collider (LHC) at CERN, due to start in 2008, will allow to measure the properties of compressed and excited nuclear matter at even higher initial densities and temperatures, far above the predicted QCD phase transition point. The longer duration of the quark-gluon plasma phase and the much more abundant production of hard probes, which depend much less on details of the later hadronic phase, will likely provide a consistent and uncontroversial experimental evidence of the QGP formation. Among the signals what witness the charge in the nature of the state of nuclear matter, the chemical equilibrium value of the strangeness plays a key role since it is directly sensitive to the matter properties and provides information on the link between the partonic and the hadronic phases. The aim of this course is to overview the underlying goals, the current status and the prospect of the physics of the nucleus-nucleus collisions at ultrarelativistic energies. Among the experimental methods adopted to investigate the challenging signatures of the QGP formation, emphasis on those related to the strangeness flavour will be given.

  15. Multi-strange baryon elliptic flow in Pb-Pb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV measured with the ALICE detector

    CERN Document Server

    Zhongbao, Yin

    2012-01-01

    We present the results on elliptic flow with multi-strange baryons produced in Pb-Pb collisions at \\sqrt{s_{NN}} = 2.76 TeV. The analysis is performed with the ALICE detector at LHC. Multi-strange baryons are reconstructed via their decay topologies and the v_2 values are analyzed with the two-particle scalar product method. The p_T differential v_2 values are compared to the VISH2+1 model calculation and to the STAR measurements at 200 GeV in Au+Au collisions. We found that the model describes \\Xi and \\Omega v_2 measurements within experimental uncertainties. The differential flow of \\Xi and \\Omega is similar to the STAR measurements at 200 GeV in Au+Au collisions.

  16. PREFACE: Strangeness in Quark Matter (SQM2009) Strangeness in Quark Matter (SQM2009)

    Science.gov (United States)

    Fraga, Eduardo; Kodama, Takeshi; Padula, Sandra; Takahashi, Jun

    2010-09-01

    The 14th International Conference on Strangeness in Quark Matter (SQM2009) was held in Brazil from 27 September to 2 October 2009 at Hotel Atlântico, Búzios, Rio de Janeiro. The conference was jointly organized by Universidade Federal do Rio de Janeiro, Universidade Estadual de Campinas, Centro Brasileiro de Pesquisas Físicas, Universidade de São Paulo, Universidade Estadual Paulista and Universidade Federal do Rio Grande do Sul. Over 120 scientists from Argentina, Brazil, China, France, Germany, Hungary, Italy, Japan, Mexico, The Netherlands, Norway, Poland, Russia, Slovakia, South Africa, Switzerland, the UK and the USA gathered at the meeting to discuss the physics of hot and dense matter through the signals of strangeness and also the behavior of heavy quarks. Group photograph The topics covered were strange and heavy quark production in nuclear collisions, strange and heavy quark production in elementary processes, bulk matter phenomena associated with strange and heavy quarks, and strangeness in astrophysics. In view of the LHC era and many other upcoming new machines, together with recent theoretical developments, sessions focused on `New developments and new facilities' and 'Open questions' were also included. A stimulating round-table discussion on 'Physics opportunities in the next decade in the view of strangeness and heavy flavor in matter' was chaired in a relaxed atmosphere by Grazyna Odyniec and conducted by P Braun-Munzinger, W Florkowski, K Redlich, K Šafařík and H Stöcker, We thank these colleagues for pointing out to young participants new physics directions to be pursued. We also thank J Dunlop and K Redlich for excellent introductory lectures given on the Sunday evening pre-conference session. In spite of the not-so-helpful weather, the beauty and charm of the town of Búzios helped to make the meeting successful. Nevertheless, the most important contributions were the excellent talks, whose contents are part of these proceedings, given

  17. Anisotropic models for compact stars

    Energy Technology Data Exchange (ETDEWEB)

    Maurya, S.K.; Dayanandan, Baiju [University of Nizwa, Department of Mathematical and Physical Sciences, College of Arts and Science, Nizwa (Oman); Gupta, Y.K. [Jaypee Institute of Information Technology University, Department of Mathematics, Noida, Uttar Pradesh (India); Ray, Saibal [Government College of Engineering and Ceramic Technology, Department of Physics, Kolkata, West Bengal (India)

    2015-05-15

    In the present paper we obtain an anisotropic analog of the Durgapal and Fuloria (Gen Relativ Gravit 17:671, 1985) perfect fluid solution. The methodology consists of contraction of the anisotropic factor Δ with the help of both metric potentials e{sup ν} and e{sup λ}. Here we consider e{sup λ} the same as Durgapal and Fuloria (Gen Relativ Gravit 17:671, 1985) did, whereas e{sup ν} is as given by Lake (Phys Rev D 67:104015, 2003). The field equations are solved by the change of dependent variable method. The solutions set mathematically thus obtained are compared with the physical properties of some of the compact stars, strange star as well as white dwarf. It is observed that all the expected physical features are available related to the stellar fluid distribution, which clearly indicates the validity of the model. (orig.)

  18. Modeling pulsations in hot stars with winds

    Energy Technology Data Exchange (ETDEWEB)

    Noels, Arlette; Godart, Melanie [Institut d' Astrophysique et de Geophysique, Liege (Belgium); Dupret, Marc-Antoine [Observatoire de Paris-Meudon, LESIA (France)], E-mail: Arlette.Noels@ulg.ac.be, E-mail: ma.dupret@obspm.fr, E-mail: Melanie.Godart@ulg.ac.be

    2008-10-15

    The interaction pulsation/mass loss takes different aspects. Pulsations can trigger mass loss as in LBVs and Miras; on the other hand, mass loss can modify the driving conditions within the stars. But the most spectacular aspect is the effect on stellar models which, in turn, opens a royal way to asteroseismology to test physical conditions inside massive stars, such as the extent of convective cores or the appearance of new driving mechanisms. We start with a discussion on MS stars and their strange mode instabilities. We then move on to the excitation of the LBV phenomenon. WR stars and the newly observed MOST period in WR123 are discussed in view of the power of asteroseismology. We then turn to B supergiants, in particular HD163899, and show how asteroseismology can really probe convection, semiconvection and mass loss.

  19. Modeling pulsations in hot stars with winds

    International Nuclear Information System (INIS)

    Noels, Arlette; Godart, Melanie; Dupret, Marc-Antoine

    2008-01-01

    The interaction pulsation/mass loss takes different aspects. Pulsations can trigger mass loss as in LBVs and Miras; on the other hand, mass loss can modify the driving conditions within the stars. But the most spectacular aspect is the effect on stellar models which, in turn, opens a royal way to asteroseismology to test physical conditions inside massive stars, such as the extent of convective cores or the appearance of new driving mechanisms. We start with a discussion on MS stars and their strange mode instabilities. We then move on to the excitation of the LBV phenomenon. WR stars and the newly observed MOST period in WR123 are discussed in view of the power of asteroseismology. We then turn to B supergiants, in particular HD163899, and show how asteroseismology can really probe convection, semiconvection and mass loss.

  20. Strangeness and the quark-gluon plasma: An experimenter's perspective

    International Nuclear Information System (INIS)

    Odyniec, G.

    1994-02-01

    Current status of experimental results on strange particle production in relativistic nucleus-nucleus collisions is reviewed. Emphasis is placed on the relevance to the hypothetical quark-gluon plasma formation and the origin of the Universe

  1. Enhancement of strangeness in relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Grassi, F.; Heiselberg, H.

    1990-01-01

    The theoretical and experimental conditions to obtain strange particle production in heavy ion collisions at high energies are discussed, by analysis of results obtained from Super Proton Synchrotron - CERN and Alternating Gradient Synchrotron in United States. (M.C.K.)

  2. Is EG 50 a White or Strange Dwarf?

    Science.gov (United States)

    Hajyan, G. S.; Vartanyan, Yu. L.

    2017-12-01

    The time dependences of the luminosity of a white dwarf and four strange dwarfs with masses of 0.5 M (the mass of the white dwarf EG 50 with a surface temperature of 2.1·104 K) are determined taking neutrino energy losses into account. It was assumed that these configurations radiate only at the expense of thermal energy reserves. It is shown that the sources of thermal energy owing to nonequilibrium b-processes and the phenomenon of crystallization of electron-nuclear matter are insignificant in determining the cooling time of white and strange dwarfs with masses of 0.5 M⨀. It is shown that in this approximation the time dependences of the luminosity of white and strange dwarfs with masses of 0.5 M⨀ differ significantly only for surface temperatures TR≥7·104 K, so it is impossible to determine whether EG 50 is a white or strange dwarf based on the cooling time.

  3. Collider phenomenology of light strange-beauty squarks

    International Nuclear Information System (INIS)

    Cheung, Kingman; Hou Weizshu

    2004-01-01

    Strong mixing between right-handed strange and beauty squarks is a possible solution to the CP violation discrepancy in B→φK S decay as recently suggested by the Belle data. In this scenario, thanks to the strong mixing one of the strange-beauty squarks can be as light as 200 GeV, even though the generic supersymmetry scale is at TeV. In this work, we study the production of this light right-handed strange-beauty squark at hadronic colliders and discuss the detection in various decay scenarios. Detection prospect at the Tevatron run II is good for the strange-beauty squark mass up to about 300 GeV

  4. Higher dimensional strange quark matter solutions in self creation cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Şen, R., E-mail: ramazansen-1991@hotmail.com [Institute for Natural and Applied Sciences, Çanakkale Onsekiz Mart University, 17020, Çanakkale (Turkey); Aygün, S., E-mail: saygun@comu.edu.tr [Department of Physics, Art and Science Faculty, Çanakkale Onsekiz Mart University, Çanakkale 17020 (Turkey)

    2016-03-25

    In this study, we have generalized the higher dimensional flat Friedmann-Robertson-Walker (FRW) universe solutions for a cloud of string with perfect fluid attached strange quark matter (SQM) in Self Creation Cosmology (SCC). We have obtained that the cloud of string with perfect fluid does not survive and the string tension density vanishes for this model. However, we get dark energy model for strange quark matter with positive density and negative pressure in self creation cosmology.

  5. Charm and strangeness of ultrarelativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Gerschel, C.

    1994-01-01

    Charmonium and strangeness production in collisions induced by ultrarelativistic sulfur or silicon ions is reviewed. A suppression of charmonium production and a strangeness enhancement are observed. Predicted as potential signatures of the quark gluon plasma formation, their interpretation is still very much debated. The status of the discussion will be given as well as the expected evolutions with the forthcoming Pb beams. (author). 45 refs., 11 figs., 1 tab

  6. Hot Strange Hadronic Matter in an Effective Model

    Institute of Scientific and Technical Information of China (English)

    QIAN Wei-Liang; SU Ru-Keng; SONG Hong-Qiu

    2003-01-01

    An effective model used to describe the strange hadronic matter with nucleons, Λ-hyperons, and Ξ-hyperonsis extended to finite temperature. The extended model is used to study the density, temperature, and strangeness fractiondependence of the effective masses of baryons in the matter. The thermodynamical quantities, such as free energy andpressure, as well as the equation of state of the matter, are given.

  7. Strangeness Production in a Chemically Equilibrating Quark-Gluon Plasma

    Institute of Scientific and Technical Information of China (English)

    HE Ze-Jun; LONG Jia-Li; MA Yu-Gang; MA Guo-Liang

    2004-01-01

    @@ We study the strangeness of a chemically equilibrating quark-gluon plasma at finite baryon density based on the and will accelerate with the change of the initial system from a chemically non-equilibrated to an equilibrated system. We also find that the calculated strangeness is very different from the one in the thermodynamic equilibrium system. This study may be helpful to understand the formation of quark-gluon plasma via a chemically non-equilibrated evolution framework.

  8. Non-Spherical Gravitational Collapse of Strange Quark Matter

    Institute of Scientific and Technical Information of China (English)

    Zade S S; Patil K D; Mulkalwar P N

    2008-01-01

    We study the non-spherical gravitational collapse of the strange quark null fluid.The interesting feature which emerges is that the non-spherical collapse of charged strange quark matter leads to a naked singularity whereas the gravitational collapse of neutral quark matter proceeds to form a black hole.We extend the earlier work of Harko and Cheng[Phys.Lett.A 266 (2000) 249]to the non-spherical case.

  9. Hot Strange Hadronic Matter in an Effective Model

    Institute of Scientific and Technical Information of China (English)

    QIANWei-Liang; SURu-Keng; SONGHong-Qiu

    2003-01-01

    An effective model used to describe the strange hadronic matter with nucleons, A-hyperons, and [I]-hyperons is extended to finite temperature. The extended model is used to study the density, temperature, and strangeness fraction dependence of the effective masses of baryons in the matter. The thermodynamical quantities, such as free energy and pressure, as well as the equation of state of the matter, are given.

  10. Theoretical study of nuclear physics with strangeness at Nankai University

    International Nuclear Information System (INIS)

    Ning Pingzhi

    2007-01-01

    Theoretical study of nuclear physics with strangeness from the nuclear physics group at Nankai university is briefly introduced. Theoretical calculations on hyperon mean free paths in nuclear medium have been done. The other 4 topics in the area of strangeness nuclear physics are the effect of different baryon impurities in nucleus, the heavy flavored baryon hypernuclei, the eta-mesons in nuclear matter and the properties of kaonic nuclei. (authors)

  11. Equation of state of strange quark matter in a strong magnetic field

    International Nuclear Information System (INIS)

    Isayev, A.A.; Yang, J.

    2012-01-01

    Thermodynamic properties of strange quark matter (SQM) in strong magnetic fields H up to 10 20 G are considered at zero temperature within the MIT bag model. The effects of the pressure anisotropy, exhibiting in the difference between the pressures along and perpendicular to the field direction, become essential at H>H t h , with the estimate 10 17 t h 18 G. The longitudinal pressure vanishes in the critical field H c , which can be somewhat less or larger than 10 18 G, depending on the total baryon number density and bag pressure. As a result, the longitudinal instability occurs in strongly magnetized SQM. The appearance of such instability sets the upper bound on the magnetic field strength which can be reached in the interior of a neutron star with the quark core. The longitudinal and transverse pressures as well as the anisotropic equation of state of SQM are determined under the conditions relevant for the cores of magnetars

  12. Stellar equilibrium configurations of compact stars in f(R,T) theory of gravity

    Science.gov (United States)

    Moraes, P. H. R. S.; Arbañil, José D. V.; Malheiro, M.

    2016-06-01

    In this article we study the hydrostatic equilibrium configuration of neutron stars and strange stars, whose fluid pressure is computed from the equations of state p=ωρ5/3 and p=0.28(ρ-4Script B), respectively, with ω and Script B being constants and ρ the energy density of the fluid. We start by deriving the hydrostatic equilibrium equation for the f(R,T) theory of gravity, with R and T standing for the Ricci scalar and trace of the energy-momentum tensor, respectively. Such an equation is a generalization of the one obtained from general relativity, and the latter can be retrieved for a certain limit of the theory. For the f(R,T)=R+2λ T functional form, with λ being a constant, we find that some physical properties of the stars, such as pressure, energy density, mass and radius, are affected when λ is changed. We show that for a fixed central star energy density, the mass of neutron and strange stars can increase with λ. Concerning the star radius, it increases for neutron stars and it decreases for strange stars with the increment of λ. Thus, in f(R,T) theory of gravity we can push the maximum mass above the observational limits. This implies that the equation of state cannot be eliminated if the maximum mass within General Relativity lies below the limit given by observed pulsars.

  13. Stellar equilibrium configurations of compact stars in f ( R , T ) theory of gravity

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, P.H.R.S.; Arbañil, José D.V.; Malheiro, M., E-mail: moraes.phrs@gmail.com, E-mail: arbanil@ita.br, E-mail: malheiro@ita.br [ITA—Instituto Tecnológico de Aeronáutica—Departamento de Física, 12228-900, São José dos Campos, São Paulo (Brazil)

    2016-06-01

    In this article we study the hydrostatic equilibrium configuration of neutron stars and strange stars, whose fluid pressure is computed from the equations of state p =ωρ{sup 5/3} and p =0.28(ρ−4B), respectively, with ω and B being constants and ρ the energy density of the fluid. We start by deriving the hydrostatic equilibrium equation for the f ( R , T ) theory of gravity, with R and T standing for the Ricci scalar and trace of the energy-momentum tensor, respectively. Such an equation is a generalization of the one obtained from general relativity, and the latter can be retrieved for a certain limit of the theory. For the f ( R , T )= R +2λ T functional form, with λ being a constant, we find that some physical properties of the stars, such as pressure, energy density, mass and radius, are affected when λ is changed. We show that for a fixed central star energy density, the mass of neutron and strange stars can increase with λ. Concerning the star radius, it increases for neutron stars and it decreases for strange stars with the increment of λ. Thus, in f ( R , T ) theory of gravity we can push the maximum mass above the observational limits. This implies that the equation of state cannot be eliminated if the maximum mass within General Relativity lies below the limit given by observed pulsars.

  14. Stars and Star Myths.

    Science.gov (United States)

    Eason, Oliver

    Myths and tales from around the world about constellations and facts about stars in the constellations are presented. Most of the stories are from Greek and Roman mythology; however, a few Chinese, Japanese, Polynesian, Arabian, Jewish, and American Indian tales are also included. Following an introduction, myths are presented for the following 32…

  15. New results on mesons containing strange quarks

    International Nuclear Information System (INIS)

    Aston, D.; Awaji, N.; Bienz, T.

    1987-01-01

    Recent results of strange and strangeonium mesons are presented. The data come from a high sensitivity study (4.1 ev/nb) of K - p interactions at 11 GeV/c using the LASS spectrometer at SLAC. The complete leading orbitally-excited K* series up through J/sup P/ = 5 - and a substantial number of the expected underlying states are observed decaying into K - π + , anti K 3 0 π + π - , and K eta final states, and new measurements are made of their masses, widths, and branching ratios. Production of strangeonium states via hypercharge exchange is observed into K 3 0 K 3 0 , K - K + , and K 3 0 K +- π -+ final states. The leading orbitally-excited phi series through J/sup P/ = 3 - is clearly seen and evidence is presented for additional high spin structure in the 2.2 GeV/c 2 region. No f 2 (1720) is observed. The K 3 0 K +- π -+ spectrum is dominated by 1 + (K* anti K + anti K* K) production in the region below 1.6 GeV/c 2 . These results are compared with data on the same systems produced by different production mechanisms. 12 refs., 28 figs

  16. ['How strange is the patient to me?'

    Science.gov (United States)

    Karger, André; Lindtner-Rudolph, Heide; Mroczynski, Robert; Ziem, Alexander; Joksimovic, Ljiljana

    2017-09-01

    'How strange is the patient to me?' Physicians' attitudes and expectations toward treating patients with a migration background Objectives: Undergraduate and postgraduate training in cultural competence remains a challenging issue. It might be useful to integrate culturally sensitive learning objectives in existing curricula. As part of a needs assessment, this qualitative study examined the prototypical experiences in clinical routines with patients with a migration background. Twenty physicians took part in half-structured narrative interviews, which were then analyzed by linguistic-ethnographic conversation analysis. The main reasons for difficulties in patient-physician relation proved to be language barriers. Assignments of professional interpreters were rated critically. Physicians attributed the responsibility for successful communication mainly to the patient. The physicians saw little need for training in cultural competence. The integration of learning objectives related to cultural sensibility in existing curricula would seem to be useful, especially because the physicians interviewed reported little need for additional training on their own. The importance of implied negative attitudes and stereotypes in creating a culturally sensitive approach should be taken into account.

  17. Strangeness Prospects with the CBM Experiment

    International Nuclear Information System (INIS)

    Friese, Volker

    2016-01-01

    The CBM experiment will study strongly interacting matter at high net-baryon densities with nuclear collisions up to 45A GeV beam energy at the future FAIR facility. With interaction rates unprecedented in heavy-ion collisions, CBM will give access also to extremely rare probes and thus to the early stage of the collisions, in search for the first-order phase transition from confined to deconfined matter and the QCD critical point. The CBM physics programme will be started with beams delivered by the SIS-100 synchrotron, providing energies from 2 to 11 GeV/nucleon for heavy nuclei, up to 14 GeV/nucleon for light nuclei, and 30 GeV for protons. The highest net baryon densities will be explored with ion beams up to 45 GeV/nucleon energy delivered by SIS-300 in a later stage of the FAIR project.After several years of preparation, the CBM experiment now enters the realisation phase. In this article, we report on the current status of the system developments and the expected physics performance for strange and charmed observables, as well as on the roadmap towards the first data taking. (paper)

  18. Spatial discrimination and visual discrimination

    DEFF Research Database (Denmark)

    Haagensen, Annika M. J.; Grand, Nanna; Klastrup, Signe

    2013-01-01

    Two methods investigating learning and memory in juvenile Gottingen minipigs were evaluated for potential use in preclinical toxicity testing. Twelve minipigs were tested using a spatial hole-board discrimination test including a learning phase and two memory phases. Five minipigs were tested...... in a visual discrimination test. The juvenile minipigs were able to learn the spatial hole-board discrimination test and showed improved working and reference memory during the learning phase. Performance in the memory phases was affected by the retention intervals, but the minipigs were able to remember...... the concept of the test in both memory phases. Working memory and reference memory were significantly improved in the last trials of the memory phases. In the visual discrimination test, the minipigs learned to discriminate between the three figures presented to them within 9-14 sessions. For the memory test...

  19. Production of multi-strange hyperons and strange resonances in the NA49 experiment

    CERN Document Server

    Barton, R A; Anticic, T; Bächler, J; Barna, D; Barnby, L S; Bartke, Jerzy; Betev, L; Bialkowska, H; Billmeier, A; Blume, C; Blyth, C O; Boimska, B; Botje, M; Bracinik, J; Brady, F P; Bramm, R; Brun, R; Buncic, P; Carr, L; Cebra, D; Cooper, G E; Cramer, J G; Csató, P; Eckhardt, F; Ferenc, D; Filip, P; Fischer, H G; Fodor, Z; Foka, P Y; Freund, P; Friese, V; Ftácnik, J; Gál, J; Gazdzicki, M; Georgopoulos, G; Gladysz-Dziadus, E; Hegyi, S; Hlinka, V; Höhne, C; Igo, G; Ivanov, M; Jacobs, P; Janik, R; Jones, P G; Kadija, K; Kolesnikov, V I; Kollegger, T; Kowalski, M; Van Leeuwen, M; Lévai, Peter; Malakhov, A I; Margetis, S; Markert, C; Mayes, B W; Melkumov, G L; Mischke, A; Molnár, J; Nelson, J M; Odyniec, Grazyna Janina; Pálla, G; Panagiotou, A D; Petridis, A; Pikna, M; Pinsky, L; Poskanzer, A M; Prindle, D J; Pühlhofer, F; Reid, J G; Renfordt, R E; Retyk, W; Ritter, H G; Röhrich, D; Roland, C; Roland, G; Rybicki, A; Sammer, T; Sandoval, A; Sann, H; Schäfer, E; Schmitz, N; Seyboth, P; Siklér, F; Sitár, B; Skrzypczak, E; Snellings, R; Squier, G T A; Stock, Reinhard; Strmen, P; Ströbele, H; Susa, T; Szarka, I; Szentpétery, I; Sziklai, J; Toy, M; Trainor, T A; Trentalange, S; Varga, D; Vassiliou, Maria; Veres, G I; Vesztergombi, G; Voloshin, S A; Vranic, D; Wang, F; Weerasundara, D D; Wenig, S; Wetzler, A; Whitten, C; Xu, N; Yates, T A; Yoo, I K; Zimányi, J

    2001-01-01

    The NA49 large-acceptance hadron spectrometer has measured strange and multi-strange hadrons from Pb+Pb and p+p collisions at the CERN SPS. Preliminary results for the transverse mass and rapidity distributions for X and Xi /sup +/ from central Pb+Pb collisions at 158 GeV c/sup -1//nudeon are presented. Fully integrated yields per event of 4.42+or-0.31 and 0.74+0.04 are found for Xi /sup -/ and Xi /sup +/, respectively, leading to a 4 pi Xi /sup +// Xi /sup -/ ratio of 0.17+or-0.02. The ratio Xi /sup +// Xi /sup -/ at mid-rapidity is found to be 0.22+or-0.04, agreeing with previously published values. In addition, preliminary data on the Lambda (1520) and phi (1020) resonances are presented. The Lambda (1520) multiplicity for p+p collisions is found to be 0.012+or-0.003. No signal is observed for Pb+Pb collisions and a production upper limit of 1.36 Lambda (1520) per event indicates an apparent suppression when comparing with scaled p+p data. Integrated phi (1020) yields per event are found to be 7.6+or-1.1 f...

  20. Discovery Mondays - “Relativity Theory... strange! Did you say strange?”

    CERN Multimedia

    2005-01-01

    We all know that famous equation E=mc2, but do you know its true significance? Relativity theory: what is the meaning of this strange concept which plunged the physics world into turmoil 100 years ago? What effects can be observed today? Did you know that the GPS system would not work if relativity was not taken into account? The next Discovery Monday will take you on a journey into a strange world. You will be able to witness for yourselves the consequences of Einstein's theories. How, for example, can relativity theory be tested by eclipses? What consequences does it have for the accelerators at CERN? How can it be used to measure the mass of enormous black holes? And finally, how is it linked to the puzzle surrounding the missing mass of the Universe? As part of the World Year of Physics, the next Discovery Monday will be dedicated to one of the theories that Einstein published in 1905, his “annus mirabilis”. Join us at the Microcosm (Reception Building 33, Meyrin site), on Monday 5th September ...

  1. Discovery Mondays - “Relativity Theory... strange! Did you say strange?”

    CERN Multimedia

    2005-01-01

    We all know that famous equation E=mc2, but do you know its true significance? Relativity theory: what is the meaning of this strange concept which plunged the physics world into turmoil 100 years ago? What effects can be observed today? Did you know that the GPS system would not work if relativity was not taken into account? The next Discovery Monday will take you on a journey into a strange world. You will be able to witness for yourselves the consequences of Einstein's theories. How, for example, can relativity theory be tested by eclipses? What consequences does it have for the accelerators at CERN? How can it be used to measure the mass of enormous black holes? And finally, how is it linked to the puzzle surrounding the missing mass of the Universe? As part of the World Year of Physics, the next Discovery Monday will be dedicated to one of the theories that Einstein published in 1905, his “annus mirabilis”. Join us at the Microcosm (Reception Building 33, Meyrin site), on Monday 5th Septemb...

  2. Observation of enhanced production of strange and multi-strange hadrons in high-multiplicity pp and p-Pb collisions with the ALICE detector.

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    The production of strange hadrons has long been studied in heavy-ion collisions to investigate the formation of a deconfined medium. The interpretation of these data depends critically on the understanding of strange-particle production in smaller ‘baseline’ collision systems such as proton-proton and proton-ion. The ALICE experiment is well-suited to the measurement of identified charged hadrons and weakly-decaying strange and multi-strange baryons and has collected large samples of minimum-bias pp and p-Pb collisions. Characterising the collisions according to their final-state multiplicities reveals an enhancement in the production of strange and multi-strange particles, relative to light flavoured hadrons. This detailed information is valuable in understanding the mechanisms that control the production of strange particles.  

  3. Mass discrimination

    Energy Technology Data Exchange (ETDEWEB)

    Broeckman, A. [Rijksuniversiteit Utrecht (Netherlands)

    1978-12-15

    In thermal ionization mass spectrometry the phenomenon of mass discrimination has led to the use of a correction factor for isotope ratio-measurements. The correction factor is defined as the measured ratio divided by the true or accepted value of this ratio. In fact this factor corrects for systematic errors of the whole procedure; however mass discrimination is often associated just with the mass spectrometer.

  4. How discriminating are discriminative instruments?

    Science.gov (United States)

    Hankins, Matthew

    2008-05-27

    The McMaster framework introduced by Kirshner & Guyatt is the dominant paradigm for the development of measures of health status and health-related quality of life (HRQL). The framework defines the functions of such instruments as evaluative, predictive or discriminative. Evaluative instruments are required to be sensitive to change (responsiveness), but there is no corresponding index of the degree to which discriminative instruments are sensitive to cross-sectional differences. This paper argues that indices of validity and reliability are not sufficient to demonstrate that a discriminative instrument performs its function of discriminating between individuals, and that the McMaster framework would be augmented by the addition of a separate index of discrimination. The coefficient proposed by Ferguson (Delta) is easily adapted to HRQL instruments and is a direct, non-parametric index of the degree to which an instrument distinguishes between individuals. While Delta should prove useful in the development and evaluation of discriminative instruments, further research is required to elucidate the relationship between the measurement properties of discrimination, reliability and responsiveness.

  5. How discriminating are discriminative instruments?

    Directory of Open Access Journals (Sweden)

    Hankins Matthew

    2008-05-01

    Full Text Available Abstract The McMaster framework introduced by Kirshner & Guyatt is the dominant paradigm for the development of measures of health status and health-related quality of life (HRQL. The framework defines the functions of such instruments as evaluative, predictive or discriminative. Evaluative instruments are required to be sensitive to change (responsiveness, but there is no corresponding index of the degree to which discriminative instruments are sensitive to cross-sectional differences. This paper argues that indices of validity and reliability are not sufficient to demonstrate that a discriminative instrument performs its function of discriminating between individuals, and that the McMaster framework would be augmented by the addition of a separate index of discrimination. The coefficient proposed by Ferguson (Delta is easily adapted to HRQL instruments and is a direct, non-parametric index of the degree to which an instrument distinguishes between individuals. While Delta should prove useful in the development and evaluation of discriminative instruments, further research is required to elucidate the relationship between the measurement properties of discrimination, reliability and responsiveness.

  6. A statistical approach to strange diffusion phenomena

    International Nuclear Information System (INIS)

    Milligen, B.Ph. van; Carreras, B.A.; Sanchez, R.

    2005-01-01

    The study of particle (and heat) transport in fusion plasmas has revealed the existence of what might be called 'unusual' transport phenomena. Such phenomena are: unexpected scaling of the confinement time with system size, power degradation (i.e. sub-linear scaling of energy content with power input), profile stiffness (also known as profile consistency), rapid transient transport phenomena such as cold and heat pulses (travelling much faster than the diffusive timescale would allow), non-local behaviour and central profile peaking during off-axis heating, associated with unexplained inward pinches. The standard modelling framework, essentially equal to Fick's Law plus extensions, has great difficulty in providing an all-encompassing and satisfactory explanation of all these phenomena. This difficulty has motivated us to reconsider the basics of the modelling of diffusive phenomena. Diffusion is based on the well-known random walk. The random walk is captured in all its generality in the Continuous Time Random Walk (CTRW) formalism. The CTRW formalism is directly related to the well-known Generalized Master Equation, which describes the behaviour of tracer particle diffusion on a very fundamental level, and from which the phenomenological Fick's Law can be derived under some specific assumptions. We show that these assumptions are not necessarily satisfied under fusion plasma conditions, in which case other equations (such as the Fokker-Planck diffusion law or the Master Equation itself) provide a better description of the phenomena. This fact may explain part of the observed 'strange' phenomena (namely, the inward pinch). To show how the remaining phenomena mentioned above may perhaps find an explanation in the proposed alternative modelling framework, we have designed a toy model that incorporates a critical gradient mechanism, switching between rapid (super-diffusive) and normal diffusive transport as a function of the local gradient. It is then demonstrated

  7. Double-strangeness five-body system

    Energy Technology Data Exchange (ETDEWEB)

    Myint, K S [Mandalay Univ. (Myanmar). Dept. of Physics; Akaishi, Yoshinori

    1994-09-01

    We perform theoretical analysis on the structure and decay of a double-strangeness five-body system which consists of {sub {Lambda}{Lambda}}{sup 5}H and {sub {identical_to}}{sup 5}H states. In this S=-2 five-body system the thresholds of the t{Lambda}{Lambda} channel and the {alpha}{identical_to}{sup -} channel come closer with only 8.51 MeV difference. We treat both bound and resonant states of the three-body channels t{Lambda}{Lambda} and tp{identical_to}{sup -} by applying a complex rotation method. It is found that there is a bound {sub {Lambda}{Lambda}}{sup 5}H state with 6.3 MeV below the threshold of t+{Lambda}+{Lambda}. In the {identical_to}{sup -} channel a resonant {sub {identical_to}}{sup 5}H state appears at 1.7 MeV below the threshold of {alpha}+{identical_to}{sup -}. Though the existence of this state is ensured by the Coulomb interaction, it is a `halo` nuclear state rather than an atomic state as judged from its size. The conversion width of this state is 0.2 MeV which is extremely narrow. It is also found that {identical_to} mixing into the {sub {Lambda}{Lambda}}{sup 5}H ground state is small with 1.0 %. For the {sub {Lambda}{Lambda}}{sup 5}H state, the weak decay to the {alpha}+{Sigma}{sup -} final state produces a high mono-energetic {Sigma}{sup -} with branching ratio of 5.5 %. Thus the {Sigma}{sup -} with discrete energy would become a clear signature of the forming of the {Lambda}{Lambda} hypernucleus. (author).

  8. Double-strangeness five-body system

    Energy Technology Data Exchange (ETDEWEB)

    Myint, K S [Mandalay Univ. (Myanmar). Dept. of Physics; Akaishi, Yoshinori

    1995-03-01

    We perform theoretical analysis on the structure and decay of a double-strangeness five-body system which consists of {sub {Lambda}{Lambda}}{sup 5}H and {sub {Xi}}{sup 5}H states. In this S=-2 five-body system the thresholds of the t{Lambda}{Lambda} channel and the {alpha}{Xi}{sup -} channel come closer with only 8.51 MeV difference. We treat both bound and resonant states of the three-body channels t{Lambda}{Lambda} and tp{Xi}{sup -} by applying a complex rotation method. It is found that there is a bound {sub {Lambda}{Lambda}}{sup 5}H state with 6.3 MeV below the threshold of t+{Lambda}+{Lambda}. In the {Xi}{sup -} channel a resonant {sub {Xi}}{sup 5}H state appears at 1.7 MeV below the threshold of {alpha}+{Xi}{sup -}. Though the existence of this state is ensured by the Coulomb interaction, it is a `halo` nuclear state rather than an atomic state as judged from its size. The conversion width of this state is 0.2 MeV which is extremely narrow. It is also found that {Xi} mixing into the {sub {Lambda}{Lambda}}{sup 5}H ground state is small with 1.0%. For the {sub {Lambda}{Lambda}}{sup 5}H state, the weak decay to the {alpha}+{Sigma}{sup -} final state produces a high mono-energetic {Sigma}{sup -} with branching ratio of 5.5%. Thus the {Sigma}{sup -} with discrete energy would become a clear signature of the forming of the {Lambda}{Lambda} hypernucleus. (author).

  9. Study of the strangeness photoproduction on deuteron

    International Nuclear Information System (INIS)

    Rouvier, F.

    1997-01-01

    Hypernuclear physics has been getting more and more attention in the last fifteen years with the realization that it is important to study hyperon - nucleon interactions in addition to nucleon - nucleon interactions in order to have a comprehensive understanding of strong interactions. One is to study final-state interactions in processes initiated with electromagnetic probes. In this thesis we focus our attention on a particular case of hyperon-nucleon interaction, namely the Λn interaction in the continuum. The reaction γd → K +Λn is ideal for this purpose. A covariant formalism developed from an effective Lagrangian and based upon an isobaric approach is used to perform a thorough study of the electromagnetic strangeness process γd → K +Λn , for 0.8 ≤ E γ ≤ 1.7 GeV. The present model using a diagrammatic technique consists of the loop Feynman's diagram evaluation by means of the relativistic impulse approximation (the neutron is considered as spectator on its mass-shell during the process). First, we have therefore to calculate the three diagram which dominates the dynamics by its pole terms and does not include the final-state interaction. A Watson-Migdal approximation is first used to incorporate the final-state interaction Λn without Λ ↔ Σ conversion. Secondly, we have calculated the full loop diagram with many potentials models in a slow-variation approximation. It consists of extracting the tree diagram amplitude T fi t from the integral which calculates the full loop diagram T fi l . In conclusion, we have examined the changes caused by (Λ - Σ)n final-state interaction on d 3σ , d 2σ and Λ polarization for various kinematical choices. (author)

  10. Non-Equilibrium Heavy Flavored Hadron Yields from Chemical Equilibrium Strangeness-Rich QGP

    OpenAIRE

    Kuznetsova, Inga; Rafelski, Johann

    2008-01-01

    The yields of heavy flavored hadrons emitted from strangeness-rich QGP are evaluated within chemical non-equilibrium statistical hadronization model, conserving strangeness, charm, and entropy yields at hadronization.

  11. Strange and non-strange baryon production in ultrarelativistic sulphur-tungsten and sulphur-sulphur collisions

    International Nuclear Information System (INIS)

    Helstrup, H.

    1993-04-01

    Relativistic heavy ion collisions provide an opportunity to create a new phase of matter, the quark gluon plasma, in the laboratory. A possible quark gluon will be very short-lived, and only its decay products can be observed. There exists no unambiguous signal to identify plasma formation yet, although several candidates have been suggested. An enhanced production of strange particles is one of these proposed signals. The WA85 experiments measures strange particle production ratios in a narrow window in rapidity and transverse momentum. At present, WA85 is the only collaboration who have published results on multi strange particles. This thesis discusses the investigation of the production of strange particles in relativistic ion collisions done by the WA85 collaboration and its successors at CERN. An enhanced production of strange particles has been suggested as a signal for plasma production. Even if no plasma is produced, the experiment may reveal interesting information on the physics of the fireball produced by colliding heavy nuclei, the highest concentration of energy presently available on Earth. 80 refs., 57 figs., 11 tabs

  12. Not strange but bizarre physics from the sample experiment

    International Nuclear Information System (INIS)

    Leinweber, D. B.

    1999-01-01

    Since the report of the SAMPLE Collaboration suggesting the strange-quark contribution to the nucleon, G M s (0), may be greater than zero, numerous models have appeared supporting positive values for G M s (0) In this paper the bizarre physics associated with G M s (0) > 0 is illustrated. Two equations are presented describing the strange quark contribution to the nucleon magnetic moment in terms of the ratio of strange to light sea-quark-loop contributions and valence-quark ratios, probing the subtle effects of environment sensitivity. The evaluations involve no approximations outside of the usual assumption of equal current quark masses. Using the new lattice QCD results, our best estimate for G M s (0) shifts slightly from G M s (0) =-0.75 ± 0.30 μ N , to G M s (0) = -0.62 ± 0.26 μ N . Copyright (1999) World Scientific Publishing Co. Pte. Ltd

  13. Neutrino dimuon production and the strangeness asymmetry of the nucleon

    International Nuclear Information System (INIS)

    Olness, F.; Nadolsky, P.; Pumplin, J.; Stump, D.; Huston, J.; Tung, W.K.; Lai, H.L.; Kretzer, S.; Owens, J.F.

    2005-01-01

    We have performed the first global QCD analysis to include the CCFR and NuTeV dimuon data, which provide direct constraints on the strange and antistrange parton distributions, s(x) and anti s(x). To explore the strangeness sector, we adopt a general parametrization of the non-perturbative s(x), anti s(x) functions satisfying basic QCD requirements. We find that the strangeness asymmetry, as represented by the momentum integral [S - ]≡∫ 0 1 x [s(x)- anti s(x)] dx, is sensitive to the dimuon data provided the theoretical QCD constraints are enforced. We use the Lagrange multiplier method to probe the quality of the global fit as a function of [S - ] and find -0.001 - ] < 0.004. Representative parton distribution sets spanning this range are given. Comparisons with previous work are made. (orig.)

  14. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Brorsen, Michael; Frigaard, Peter

    Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star.......Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star....

  15. Limiting rotational period of neutron stars

    Science.gov (United States)

    Glendenning, Norman K.

    1992-11-01

    We seek an absolute limit on the rotational period for a neutron star as a function of its mass, based on the minimal constraints imposed by Einstein's theory of relativity, Le Chatelier's principle, causality, and a low-density equation of state, uncertainties in which can be evaluated as to their effect on the result. This establishes a limiting curve in the mass-period plane below which no pulsar that is a neutron star can lie. For example, the minimum possible Kepler period, which is an absolute limit on rotation below which mass shedding would occur, is 0.33 ms for a M=1.442Msolar neutron star (the mass of PSR1913+16). A still lower curve, based only on the structure of Einstein's equations, limits any star whatsoever to lie in the plane above it. Hypothetical stars such as strange stars, if the matter of which they are made is self-bound in bulk at a sufficiently large equilibrium energy density, can lie in the region above the general-relativistic forbidden region, and in the region forbidden to neutron stars.

  16. Limiting rotational period of neutron stars

    International Nuclear Information System (INIS)

    Glendenning, N.K.

    1992-01-01

    We seek an absolute limit on the rotational period for a neutron star as a function of its mass, based on the minimal constraints imposed by Einstein's theory of relativity, Le Chatelier's principle, causality, and a low-density equation of state, uncertainties in which can be evaluated as to their effect on the result. This establishes a limiting curve in the mass-period plane below which no pulsar that is a neutron star can lie. For example, the minimum possible Kepler period, which is an absolute limit on rotation below which mass shedding would occur, is 0.33 ms for a M=1.442M circle-dot neutron star (the mass of PSR1913+16). A still lower curve, based only on the structure of Einstein's equations, limits any star whatsoever to lie in the plane above it. Hypothetical stars such as strange stars, if the matter of which they are made is self-bound in bulk at a sufficiently large equilibrium energy density, can lie in the region above the general-relativistic forbidden region, and in the region forbidden to neutron stars

  17. Tidal Love numbers of neutron and self-bound quark stars

    International Nuclear Information System (INIS)

    Postnikov, Sergey; Prakash, Madappa; Lattimer, James M.

    2010-01-01

    Gravitational waves from the final stages of inspiraling binary neutron stars are expected to be one of the most important sources for ground-based gravitational wave detectors. The masses of the components are determinable from the orbital and chirp frequencies during the early part of the evolution, and large finite-size (tidal) effects are measurable toward the end of inspiral, but the gravitational wave signal is expected to be very complex at this time. Tidal effects during the early part of the evolution will form a very small correction, but during this phase the signal is relatively clean. The accumulated phase shift due to tidal corrections is characterized by a single quantity related to a star's tidal Love number. The Love number is sensitive, in particular, to the compactness parameter M/R and the star's internal structure, and its determination could provide an important constraint to the neutron star radius. We show that Love numbers of self-bound strange quark matter stars are qualitatively different from those of normal neutron stars. Observations of the tidal signature from coalescing compact binaries could therefore provide an important, and possibly unique, way to distinguish self-bound strange quark stars from normal neutron stars. Tidal signatures from self-bound strange quark stars with masses smaller than 1M · are substantially smaller than those of normal stars owing to their smaller radii. Thus tidal signatures of stars less massive than 1M · are probably not detectable with Advanced LIGO. For stars with masses in the range 1-2M · , the anticipated efficiency of the proposed Einstein telescope would be required for the detection of tidal signatures.

  18. Strange attractor in the Potts spin glass on hierarchical lattices

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Washington de [Universidade Federal de Pernambuco, Centro Acadêmico do Agreste, Pernambuco (Brazil); Camelo-Neto, G. [Universidade Federal de Alagoas, Núcleo de Ciências Exatas, Laboratório de Física Teórica e Computacional, CEP 57309-005 Arapiraca, Alagoas (Brazil); Coutinho, S., E-mail: sergio@ufpe.br [Universidade Federal de Pernambuco, Departamento de Física, Laboratório de Física Teórica e Computacional, Cidade Universitária, CEP 50670-901 Recife, Pernambuco (Brazil)

    2013-11-29

    The spin-glass q-state Potts model on d-dimensional diamond hierarchical lattices is investigated by an exact real space renormalization group scheme. Above a critical dimension d{sub l}(q) for q>2, the coupling constants probability distribution flows to a low-temperature strange attractor or to the high-temperature paramagnetic fixed point, according to the temperature is below or above the critical temperature T{sub c}(q,d). The strange attractor was investigated considering four initial different distributions for q=3 and d=5 presenting strong robustness in shape and temperature interval suggesting a condensed phase with algebraic decay.

  19. A strange horn between Paolo Mantegazza and Charles Darwin.

    Science.gov (United States)

    Garbarino, Carla; Mazzarello, Paolo

    2013-09-01

    During the preparation of an exhibition in Pavia dedicated to the centennial anniversary of the death of the Italian Pathologist Paolo Mantegazza, a strange cheratinic horn was found at the Museum for the History of the University of Pavia labelled as 'spur of a cock transplanted into an ear of a cow.' After some historical investigation, we found this strange object was at the centre of a scientific correspondence between Mantegazza and Charles Darwin, who made reference to it in his book The Variation of Animals and Plants under Domestication. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Search for Exotic Strange Dibaryon in Relativistic Heavy Ion Collisions

    Institute of Scientific and Technical Information of China (English)

    GAO Chong-Shou

    2003-01-01

    The exotic strange dibaryon particle (ΩΩ)0+ with S = -6 can be produced in relativistic heavyioncollisions. The yields of this kind of exotic strange dibaryon particles can increase significantly soon as the formation ofQGP does exhibit after the collision. If there is no phase transition after the collision, the upper bound of the productionof this diomega can be estimated from the free hadronic gas model for nuclear matter. The relative yield ratio of diomegato deuteron is less than 0.000205, this means that if there is no QGP creation it is difficult to observe the production ofdiomega in relativistic heavy ion collisions.

  1. Search for Exotic Strange Dibaryon in Relativistic Heavy Ion Collisions

    Institute of Scientific and Technical Information of China (English)

    GAOChong-Shou

    2003-01-01

    The exotic strange dibaryon particle (ΩΩ)0+ with S = -6 can be produced in relativistic heavy ion collisions. The yields of this kind of exotic strange dibaryon particles can increase signitlcantly soon as the formation of QGP does exhibit after the collision. If there is no phase transition after the collision, the upper bound of the production of this diomega can be estimated from the free hadronic gas model for nuclear matter. The relative yield ratio of diomega to deuteron is less than 0.000205, this means that if there is no QGP creation it is difficult to observe the production of diomega in relativistic heavy ion collisions.

  2. Statistical properties of chaotic dynamical systems which exhibit strange attractors

    International Nuclear Information System (INIS)

    Jensen, R.V.; Oberman, C.R.

    1981-07-01

    A path integral method is developed for the calculation of the statistical properties of turbulent dynamical systems. The method is applicable to conservative systems which exhibit a transition to stochasticity as well as dissipative systems which exhibit strange attractors. A specific dissipative mapping is considered in detail which models the dynamics of a Brownian particle in a wave field with a broad frequency spectrum. Results are presented for the low order statistical moments for three turbulent regimes which exhibit strange attractors corresponding to strong, intermediate, and weak collisional damping

  3. Strange magnetism and the anapole structure of the proton

    International Nuclear Information System (INIS)

    Hasty, R.; Beck, D.H.; Danagoulian, A.; Blake, A.; Carr, R.; Covrig, S.; Filipoone, B.W.; Ito, T.M.; Gao, J.; Jones, C.E.; Lee, P.; McKeown, R.D.; Savu, V.; Beise, E.J.; Breuer, H.; Spayde, D.T.; Tieulent, R.; Herda, M.C.; Barkhuff, D.; Dodson, G.; Dow, K.; Farkhondeh, M.; Kowalski, S.; Tsentalovich, E.; Yang, B.; Zwart, T.; Hawthorne-Allen, A.M.; Pitt, M.; Ritter, J.; Korsch, W.; Mueller, B.; Wells, S.P.; Averett, T.; Roche, J.; Kramer, K.

    2000-01-01

    The violation of mirror symmetry in the weak force provides a powerful tool to study the internal structure of the proton. Experimental results have been obtained that address the role of strange quarks in generating nuclear magnetism. The measurement reported here provides an unambiguous constraint on strange quark contributions to the proton's magnetic moment through the electron-proton weak interaction. We also report evidence for the existence of a parity-violating electromagnetic effect known as the anapole moment of the proton. The proton's anapole moment is not yet well understood theoretically, but it could have important implications for precision weak interaction studies in atomic systems such as cesium.

  4. Strangeness production and propagation in relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Herrmann, N.

    1997-01-01

    Strangeness production is studied with the FOPI detector at GSI in the reaction 58 Ni + 58 Ni at 1.93 AGeV. K + and Λ momentum space distributions are compatible with the assumption of kinetic equilibrium with the baryons. The extrapolated production yields are in variance with chemical equilibrium. Effects of possible in-medium modification of the strange meson masses on the experimental observables are discussed. The directed sideward flow of kaons is used as an additional probe of the in-medium properties. (authors)

  5. Strangeness production in nuclear collisions: Color rope formations?

    International Nuclear Information System (INIS)

    Toneev, V.D.; Amelin, N.S.; Csernai, L.P.; Gudima, K.K.; Sivoklokov, S.Yu.

    1992-12-01

    Strangeness production at SPS-CERN energies is studied within the Quark Gluon String Model. This analysis indicates that the observed shape of rapidity and transverse mass distributions are reproduced fairly well for both peripheral and central heavy ion collisions. However, for central collisions the model underpredicts strange particles abundance by a factor of about 2:2:4 for K S 0 , Λ and anti Λ, respectively. This discrepancy can be considered as a possible manifestation of string-string interactions of a collective type similar to the formation of a color rope. The model predictions for coming experiments with the Pb beam at CERN are given. (orig.)

  6. Life Is Strange : a mediated game reception analysis

    OpenAIRE

    Mänder, Leili

    2017-01-01

    In this essay a mediated video game reception of the game Life Is Strange is made, with the purpose of examining the players' meaning-making processes from a gender perspective. The materials of this essay consist of videos from six different YouTube channels where each player film themselves whilst playing through Life Is Strange as a way to review and share the gaming experience. The results show how the meaning-making processes are littered with gender discourses and affects. The affects o...

  7. Charm and strange quark contributions to the proton structure

    Energy Technology Data Exchange (ETDEWEB)

    Torokoff, K

    1999-02-01

    The possibility to have charm and strange quarks as quantum mechanical fluctuations in the proton wave function is investigated based on a model for non-perturbative QCD dynamics. Both hadron and parton basis are examined. A scheme for energy fluctuations is constructed and compared with explicit energy-momentum conservation. Resulting momentum distributions for charm and strange quarks in the proton are derived at the starting scale Q{sub 0} for the perturbative QCD evolution. Kinematical constraints are found to be important when comparing to the `intrinsic charm` model 20 refs, 30 figs, 9 tabs

  8. Charm and strange quark contributions to the proton structure

    International Nuclear Information System (INIS)

    Torokoff, K.

    1999-02-01

    The possibility to have charm and strange quarks as quantum mechanical fluctuations in the proton wave function is investigated based on a model for non-perturbative QCD dynamics. Both hadron and parton basis are examined. A scheme for energy fluctuations is constructed and compared with explicit energy-momentum conservation. Resulting momentum distributions for charm and strange quarks in the proton are derived at the starting scale Q 0 for the perturbative QCD evolution. Kinematical constraints are found to be important when comparing to the 'intrinsic charm' model

  9. Magnetized color flavor locked state and compact stars

    CERN Document Server

    Felipe, R Gonzalez; Martinez, A Perez

    2010-01-01

    The stability of the color flavor locked phase in the presence of a strong magnetic field is investigated within the phenomenological MIT bag model, taking into account the variation of the strange quark mass, the baryon density, the magnetic field, as well as the bag and gap parameters. It is found that the minimum value of the energy per baryon in a color flavor locked state at vanishing pressure is lower than the corresponding one for unpaired magnetized strange quark matter and, as the magnetic field increases, the energy per baryon decreases. This implies that magnetized color flavor locked matter is more stable and could become the ground state inside neutron stars. The mass-radius relation for such stars is also studied.

  10. Relativistic modeling of compact stars for anisotropic matter distribution

    Energy Technology Data Exchange (ETDEWEB)

    Maurya, S.K. [University of Nizwa, Department of Mathematical and Physical Sciences, College of Arts and Science, Nizwa (Oman)

    2017-05-15

    In this paper we have solved Einstein's field equations of spherically symmetric spacetime for anisotropic matter distribution by assuming physically valid expressions of the metric function e{sup λ} and radial pressure (p{sub r}). Next we have discussed the physical properties of the model in details by taking the radial pressure p{sub r} equal to zero at the boundary of the star. The physical analysis of the star indicates that its model parameters such as density, redshift, radial pressure, transverse pressure and anisotropy are well behaved. Also we have obtained the mass and radius of our compact star which are 2.29M {sub CircleDot} and 11.02 km, respectively. It is observed that the model obtained here for compact stars is compatible with the mass and radius of the strange star PSR 1937 +21. (orig.)

  11. Assessment of the biological effects of 'strange' radiation

    International Nuclear Information System (INIS)

    Pryakhin, E.A.; Tryapitsina, G.A.; Urutskoyev, L.I.; Akleyev, A.V.

    2006-01-01

    The results from studies of the effects produced by electrical explosions of foils made from super pure materials in water point to the emergence of new chemical elements. An additional finding was the discharge of 'strange' radiation accompanying the transformation of chemical elements. However, currently, the mechanism involved in the interaction between 'strange' radiation and a substance or a biological entity remains obscure. Therefore, the aim of the present research is to investigate the biological effects of the 'strange' radiation. Pilot studies were performed at the RECOM RRC 'Kurchatov Institute' in April-May of 2004. The animals used in the experiment were female mice of C57Bl/6 line aged 80 days with body weight 16-18 g. The animals were exposed to radiation discharged during explosions of Ti foils in water and aqueous solutions. The cages with animals were placed at 1 m from the epicenter of the explosion. Explosions were carried out on the 19. (3 explosions), 20. (4 explosions) and 22. (3 explosions) of April, 2004 (explosions No1373 - No1382, respectively). The animals were assigned to 4 experimental groups comprised of 17-20 mice per group. The animals received experimental exposure within 1, 2 and 3 days of the experiment. In total, the experimental groups were exposed to 3, 7 and 10 explosions, respectively. In order to identify the biological reactions, the following parameters were estimated: number of nucleated cells in the bone marrow, number of CFU in the spleen after additional gamma-irradiation (6 Gy), cell composition of the bone marrow, the rate of erythrocytes with the different level of maturation in the bone marrow, the rate of erythrocytes with the micronuclei in the bone marrow, the reaction of bone marrow cells to additional gamma-irradiation (2 Gy), number of leucocytes in the peripheral blood, and cell composition of the peripheral blood. The following conclusions were drawn from these studies: 1. 'strange' radiation resulting

  12. Study of Strange Quark Mass in CFL Phase

    Institute of Scientific and Technical Information of China (English)

    LI Xin; L(U) Xiao-Fu

    2006-01-01

    In this paper we introduce bilocal fields in the global color symmetry model and consider color and electrical neutrality conditions simultaneously to study the effect of strange quark mass Ms for the momentum-dependent condensate of color-flavor locked phase. Consequently we find that there will be a quantum phase transition occurring.

  13. Strangeness production in proton–proton and proton–nucleus ...

    Indian Academy of Sciences (India)

    Therefore, the strangeness production is expected to provide information about the resonances lying at higher excitation energies. For beam energies very close to the kaon production threshold the hyperon–proton final state interaction effects are quite important. Thus, these studies provide a check on the models of ...

  14. Finite Volume Effect of Baryons in Strange Hadronic Matter

    Institute of Scientific and Technical Information of China (English)

    SUN Bao-Xi; LI Lei; NING Ping-Zhi; ZHAO En-Guang

    2001-01-01

    The finite volume effect of baryons in strange hadronic matter (SHM) is studied within the framework of relativistic mean-field theory. As this effect is concerned, the saturation density of SHM turns lower, and the binding energy per baryon decreases. Its influence to the compression modulus of SHM is also discussed.

  15. Evidence for strange kinetics in Hasegawa-Mima turbulent transport

    International Nuclear Information System (INIS)

    Annibaldi, S.V.; Drury, L.O'C.; Manfredi, G.; Dendy, R.O.

    2000-01-01

    We have studied the transport of test particle ensembles moving in turbulent electrostatic fields governed by the Hasegawa-Mima (HM) equation. As a result of the interplay of the linear dispersive term and the nonlinear term in the HM equation, 'strange kinetics' emerge: the poloidal particle transport undergoes a qualitative transition from diffusive, through supradiffusive, to ballistic. (author). Letter-to-the-editor

  16. Plane Symmetric Cosmological Model with Quark and Strange ...

    Indian Academy of Sciences (India)

    Keywords. f(R,T) theory of gravity—plane symmetric space-time—quark and strange quark matter—constant deceleration parameter. 1. Introduction. Modern astrophysical observations point out that present expansion of the Universe is an accelerated epoch. The most fascinating evidence for this is found in measurements ...

  17. Strangeness production in proton–proton and proton–nucleus ...

    Indian Academy of Sciences (India)

    journal of. April 2006 physics pp. 765–780. Strangeness production in ... computing power necessary for the numerical treatment, lattice QCD has only ... tering reactions, it is necessary to use effective methods for the description of the ..... nucleus, it provides an appropriate tool to learn about the behaviour of the nuclear.

  18. Strangeness Production in Jets with ALICE at the LHC

    Science.gov (United States)

    Smith, Chrismond; Harton, Austin; Garcia, Edmundo; Alice Collaboration

    2016-03-01

    The study of strange particle production is an important tool for understanding the properties of the hot and dense QCD medium created in heavy-ion collisions at ultra-relativistic energies. The study of strange particles in these collisions provides information on parton fragmentation, a fundamental QCD process. While measurements at low and intermediate pT, are already in progress at the LHC, the study of high momentum observables is equally important for a complete understanding of the QCD matter, this can be achieved by studying jet interactions. We propose the measurement of the characteristics of the jets containing strange particles. Starting with proton-proton collisions, we have calculated the inclusive pTJet spectra and the spectra for jets containing strange particles (K-short or lambda), and we are extending this analysis to lead-lead collisions. In this talk the ALICE experiment will be described, the methodology used for the data analysis and the available results will be discussed. This material is based upon work supported by the National Science Foundation under Grants PHY-1305280 and PHY-1407051.

  19. Strange hadronic physics in electroproduction experiments at the Mainz Microtron

    Czech Academy of Sciences Publication Activity Database

    Achenbach, P.; Esser, A.; Gayoso, C. A.; Böhm, R.; Borodina, O.; Bosnar, D.; Bozkurt, V.; Bydžovský, Petr; Debenjak, L.; Distler, M. O.; Friscic, I.; Fujii, Y.; Gogami, T.; Gomez, M.R.; Hashimoto, O.; Hirose, S.; Kim, E.; Margaryan, A.; Merkel, H.; Müller, U.; Nagao, S.; Nakamura, S. N.; Pochodzalla, J.; Rappold, C.; Reinhold, J.; Saito, T.; Lorente, A.S.; Majos, S. S.; Schlimme, B. S.; Schoth, M.; Schulz, F.; Sfienti, C.; Sirca, S.; Tang, L.; Thiel, M.; Tsukada, K.

    2012-01-01

    Roč. 881, 5/6 (2012), s. 187-198 ISSN 0375-9474 R&D Projects: GA MŠk(CZ) LG11005 Institutional support: RVO:61389005 Keywords : strangeness reactions * Kaon electroproduction * missing mass spectroscopy * hypernuclei * decay-pion spectroscopy Subject RIV: BE - Theoretical Physics Impact factor: 1.525, year: 2012

  20. Strangeness production in pA and AA collisions at 158 A GeV

    Institute of Scientific and Technical Information of China (English)

    王晓荣[1; 萨本豪[2; 周代翠[3; 刘涵[4; 蔡勖[5

    2000-01-01

    LUCIAE, a hadronic and string cascade model and its corresponding event generator are used to analyse strangeness production singly and multiply in p-Pb and Pb-Pb collisions at 158 A GeV. Spectra of multiplicity and transverse mass for single (Α ,Α ) and multiple (Ε Ε ) strangeness are given. in LUCIAE model it suggests a physical mechanism, i.e. the dependence of the strange quark suppression factor on incident energy, projectile mass and centrality of colliding sys-tem might result in increase of yield of strange particles with increasing the above three parameters. Calculations from the model reconstruct well the WA97 experimental data: increase of yield of strange particles with increasing centrality and increase of strangeness enhancement with increasing number of strange quarks, in relativistic nucleus-nucleus collisions.

  1. Strangeness production in pA and AA collisions at 158 A GeV

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    LUCIAE, a hadronic and string cascade model and its corresponding event generator are used to analyse strangeness production singly and multiply in p-Pb and Pb-Pb collisions at 158 A GeV. Spectra of multiplicity and transverse mass for single (Λ, Λ) and multiple (Ξ-, Ξ-, Ω-, Ω-) strangeness are given. In LUCIAE model it suggests a physical mechanism, i.e. the dependence of the strange quark suppression factor on incident energy, projectile mass and centrality of colliding system might result in increase of yield of strange particles with increasing the above three parameters. Calculations from the model reconstruct well the WA97 experimental data: increase of yield of strange particles with increasing centrality and increase of strangeness enhancement with increasing number of strange quarks, in relativistic nucleus-nucleus collisions.

  2. Enhanced production of multi-strange hadrons in high-multiplicity proton–proton collisions

    CERN Document Server

    Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahmad, Shakeel; Ahn, Sang Un; Aiola, Salvatore; Akindinov, Alexander; Alam, Sk Noor; Silva De Albuquerque, Danilo; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; An, Mangmang; Andrei, Cristian; Andrews, Harry Arthur; Andronic, Anton; Anguelov, Venelin; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Arnaldi, Roberta; Arnold, Oliver Werner; Arsene, Ionut Cristian; Arslandok, Mesut; Audurier, Benjamin; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Balasubramanian, Supraja; Baldisseri, Alberto; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartalini, Paolo; Barth, Klaus; Bartke, Jerzy Gustaw; Bartsch, Esther; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bello Martinez, Hector; Bellwied, Rene; Belmont Iii, Ronald John; Belmont Moreno, Ernesto; Espinoza Beltran, Lucina Gabriela; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Biro, Gabor; Biswas, Rathijit; Biswas, Saikat; Bjelogrlic, Sandro; Blair, Justin Thomas; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boggild, Hans; Boldizsar, Laszlo; Bombara, Marek; Bonora, Matthias; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Borri, Marcello; Bossu, Francesco; Botta, Elena; Bourjau, Christian; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brucken, Erik Jens; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Bashir Butt, Jamila; Buxton, Jesse Thomas; Cabala, Jan; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calero Diaz, Liliet; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Carena, Francesco; Carena, Wisla; Carnesecchi, Francesca; Castillo Castellanos, Javier Ernesto; Castro, Andrew John; Casula, Ester Anna Rita; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Cerkala, Jakub; Chang, Beomsu; Chapeland, Sylvain; Chartier, Marielle; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chauvin, Alex; Chelnokov, Volodymyr; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Cho, Soyeon; Chochula, Peter; Choi, Kyungeon; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Crkovska, Jana; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dahms, Torsten; Dainese, Andrea; Danisch, Meike Charlotte; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; De Caro, Annalisa; De Cataldo, Giacinto; De Conti, Camila; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; Derradi De Souza, Rafael; Deisting, Alexander; Deloff, Andrzej; Denes, Ervin Sandor; Deplano, Caterina; Dhankher, Preeti; Di Bari, Domenico; Di Mauro, Antonio; Di Nezza, Pasquale; Di Ruzza, Benedetto; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Drozhzhova, Tatiana; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Ehlers Iii, Raymond James; Elia, Domenico; Endress, Eric; Engel, Heiko; Epple, Eliane; Erazmus, Barbara Ewa; Erdemir, Irem; Erhardt, Filip; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Eum, Jongsik; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabbietti, Laura; Fabris, Daniela; Faivre, Julien; Fantoni, Alessandra; Fasel, Markus; Feldkamp, Linus; Feliciello, Alessandro; Feofilov, Grigorii; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Feuillard, Victor Jose Gaston; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Francisco, Audrey; Frankenfeld, Ulrich Michael; Fronze, Gabriele Gaetano; Fuchs, Ulrich; Furget, Christophe; Furs, Artur; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gajdosova, Katarina; Gallio, Mauro; Duarte Galvan, Carlos; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Gao, Chaosong; Garabatos Cuadrado, Jose; Garcia-Solis, Edmundo Javier; Garg, Kunal; Gargiulo, Corrado; Gasik, Piotr Jan; Gauger, Erin Frances; Germain, Marie; Gheata, Mihaela; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Giubilato, Piero; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez Coral, Diego Mauricio; Gomez Ramirez, Andres; Sanchez Gonzalez, Andres; Gonzalez, Victor; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Grabski, Varlen; Grachov, Oleg Anatolievich; Graczykowski, Lukasz Kamil; Graham, Katie Leanne; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grynyov, Borys; Grion, Nevio; Gronefeld, Julius Maximilian; Grosse-Oetringhaus, Jan Fiete; Grosso, Raffaele; Gruber, Lukas; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Gulbrandsen, Kristjan Herlache; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Haake, Rudiger; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hamon, Julien Charles; Harris, John William; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Hellbar, Ernst; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Herrmann, Florian; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hillemanns, Hartmut; Hippolyte, Boris; Horak, David; Hosokawa, Ritsuya; Hristov, Peter Zahariev; Hughes, Charles; Humanic, Thomas; Hussain, Nur; Hussain, Tahir; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Inaba, Motoi; Incani, Elisa; Ippolitov, Mikhail; Irfan, Muhammad; Isakov, Vladimir; Ivanov, Marian; Ivanov, Vladimir; Izucheev, Vladimir; Jacak, Barbara; Jacazio, Nicolo; Jacobs, Peter Martin; Jadhav, Manoj Bhanudas; Jadlovska, Slavka; Jadlovsky, Jan; Jahnke, Cristiane; Jakubowska, Monika Joanna; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jusko, Anton; Kalinak, Peter; Kalweit, Alexander Philipp; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karayan, Lilit; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Khatun, Anisa; Kileng, Bjarte; Kim, Do Won; Kim, Dong Jo; Kim, Daehyeok; Kim, Hyeonjoong; Kim, Jinsook; Kim, Jiyoung; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Carsten; Klein, Jochen; Klein-Boesing, Christian; Klewin, Sebastian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobdaj, Chinorat; Kofarago, Monika; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Kondratyuk, Evgeny; Konevskikh, Artem; Kopcik, Michal; Kour, Mandeep; Kouzinopoulos, Charalampos; Kovalenko, Oleksandr; Kovalenko, Vladimir; Kowalski, Marek; Koyithatta Meethaleveedu, Greeshma; Kralik, Ivan; Kravcakova, Adela; Krivda, Marian; Krizek, Filip; Kryshen, Evgeny; Krzewicki, Mikolaj; Kubera, Andrew Michael; Kucera, Vit; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kumar, Ajay; Kumar, Jitendra; Kumar, Lokesh; Kumar, Shyam; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Ladron De Guevara, Pedro; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lapidus, Kirill; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; Laudi, Elisa; Lea, Ramona; Leardini, Lucia; Lee, Seongjoo; Lehas, Fatiha; Lehner, Sebastian; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leon Monzon, Ildefonso; Leon Vargas, Hermes; Leoncino, Marco; Levai, Peter; Li, Shuang; Li, Xiaomei; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loginov, Vitaly; Loizides, Constantinos; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lowe, Andrew John; Luettig, Philipp Johannes; Lunardon, Marcello; Luparello, Grazia; Lupi, Matteo; Lutz, Tyler Harrison; Maevskaya, Alla; Mager, Magnus; Mahajan, Sanjay; Mahmood, Sohail Musa; Maire, Antonin; Majka, Richard Daniel; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manko, Vladislav; Manso, Franck; Manzari, Vito; Mao, Yaxian; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Margutti, Jacopo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martin, Nicole Alice; Martinengo, Paolo; Martinez Hernandez, Mario Ivan; Martinez-Garcia, Gines; Martinez Pedreira, Miguel; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Mastroserio, Annalisa; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel Anthony; Mazzilli, Marianna; Mazzoni, Alessandra Maria; Mcdonald, Daniel; Meddi, Franco; Melikyan, Yuri; Menchaca-Rocha, Arturo Alejandro; Meninno, Elisa; Mercado-Perez, Jorge; Meres, Michal; Mhlanga, Sibaliso; Miake, Yasuo; Mieskolainen, Matti Mikael; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Mishra, Tribeni; Miskowiec, Dariusz Czeslaw; Mitra, Jubin; Mitu, Ciprian Mihai; Mohammadi, Naghmeh; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Montes Prado, Esther; Moreira De Godoy, Denise Aparecida; Perez Moreno, Luis Alberto; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Mulligan, James Declan; Gameiro Munhoz, Marcelo; Munning, Konstantin; Munzer, Robert Helmut; Murakami, Hikari; Murray, Sean; Musa, Luciano; Musinsky, Jan; Naik, Bharati; Nair, Rahul; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Naru, Muhammad Umair; Ferreira Natal Da Luz, Pedro Hugo; Nattrass, Christine; Rosado Navarro, Sebastian; Nayak, Kishora; Nayak, Ranjit; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Negrao De Oliveira, Renato Aparecido; Nellen, Lukas; Ng, Fabian; Nicassio, Maria; Niculescu, Mihai; Niedziela, Jeremi; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Cabanillas Noris, Juan Carlos; Norman, Jaime; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Ohlson, Alice Elisabeth; Okatan, Ali; Okubo, Tsubasa; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Oliver, Michael Henry; Onderwaater, Jacobus; Oppedisano, Chiara; Orava, Risto; Oravec, Matej; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozdemir, Mahmut; Pachmayer, Yvonne Chiara; Pagano, Davide; Pagano, Paola; Paic, Guy; Pal, Susanta Kumar; Palni, Prabhakar; Pan, Jinjin; Pandey, Ashutosh Kumar; Papikyan, Vardanush; Pappalardo, Giuseppe; Pareek, Pooja; Park, Woojin; Parmar, Sonia; Passfeld, Annika; Paticchio, Vincenzo; Patra, Rajendra Nath; Paul, Biswarup; Pei, Hua; Peitzmann, Thomas; Peng, Xinye; Pereira Da Costa, Hugo Denis Antonio; Peresunko, Dmitry Yurevich; Perez Lezama, Edgar; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petrov, Viacheslav; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Ozelin De Lima Pimentel, Lais; Pinazza, Ombretta; Pinsky, Lawrence; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Planinic, Mirko; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polishchuk, Boris; Poljak, Nikola; Poonsawat, Wanchaloem; Pop, Amalia; Poppenborg, Hendrik; Porteboeuf, Sarah Julie; Porter, R Jefferson; Pospisil, Jan; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puccio, Maximiliano; Puddu, Giovanna; Pujahari, Prabhat Ranjan; Punin, Valery; Putschke, Jorn Henning; Qvigstad, Henrik; Rachevski, Alexandre; Raha, Sibaji; Rajput, Sonia; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Rami, Fouad; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Ravasenga, Ivan; Read, Kenneth Francis; Redlich, Krzysztof; Reed, Rosi Jan; Rehman, Attiq Ur; Reichelt, Patrick Simon; Reidt, Felix; Ren, Xiaowen; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Reygers, Klaus Johannes; Riabov, Viktor; Ricci, Renato Angelo; Richert, Tuva Ora Herenui; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Ristea, Catalin-Lucian; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roeed, Ketil; Rogochaya, Elena; Rohr, David Michael; Roehrich, Dieter; Ronchetti, Federico; Ronflette, Lucile; Rosnet, Philippe; Rossi, Andrea; Roukoutakis, Filimon; Roy, Ankhi; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Ryabov, Yury; Rybicki, Andrzej; Saarinen, Sampo; Sadhu, Samrangy; Sadovskiy, Sergey; Safarik, Karel; Sahlmuller, Baldo; Sahoo, Pragati; Sahoo, Raghunath; Sahoo, Sarita; Sahu, Pradip Kumar; Saini, Jogender; Sakai, Shingo; Saleh, Mohammad Ahmad; Salzwedel, Jai Samuel Nielsen; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Sarkar, Debojit; Sarkar, Nachiketa; Sarma, Pranjal; Scapparone, Eugenio; Scarlassara, Fernando; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schmidt, Martin; Schuchmann, Simone; Schukraft, Jurgen; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Rebecca Michelle; Sefcik, Michal; Seger, Janet Elizabeth; Sekiguchi, Yuko; Sekihata, Daiki; Selyuzhenkov, Ilya; Senosi, Kgotlaesele; Senyukov, Serhiy; Serradilla Rodriguez, Eulogio; Sevcenco, Adrian; Shabanov, Arseniy; Shabetai, Alexandre; Shadura, Oksana; Shahoyan, Ruben; Shangaraev, Artem; Sharma, Ankita; Sharma, Mona; Sharma, Monika; Sharma, Natasha; Sheikh, Ashik Ikbal; Shigaki, Kenta; Shou, Qiye; Shtejer Diaz, Katherin; Sibiryak, Yury; Siddhanta, Sabyasachi; Sielewicz, Krzysztof Marek; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine Micaela; Simatovic, Goran; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singhal, Vikas; Sarkar - Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Slupecki, Maciej; Smirnov, Nikolai; Snellings, Raimond; Snellman, Tomas Wilhelm; Song, Jihye; Song, Myunggeun; Song, Zixuan; Soramel, Francesca; Sorensen, Soren Pontoppidan; Sozzi, Federica; Spiriti, Eleuterio; Sputowska, Iwona Anna; Spyropoulou-Stassinaki, Martha; Stachel, Johanna; Stan, Ionel; Stankus, Paul; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Strmen, Peter; Alarcon Do Passo Suaide, Alexandre; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais Kazim Oglu; Suljic, Miljenko; Sultanov, Rishat; Sumbera, Michal; Sumowidagdo, Suharyo; Swain, Sagarika; Szabo, Alexander; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej Pawel; Tabassam, Uzma; Takahashi, Jun; Tambave, Ganesh Jagannath; Tanaka, Naoto; Tarhini, Mohamad; Tariq, Mohammad; Tarzila, Madalina-Gabriela; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terasaki, Kohei; Terrevoli, Cristina; Teyssier, Boris; Thaeder, Jochen Mathias; Thakur, Dhananjaya; Thomas, Deepa; Tieulent, Raphael Noel; Tikhonov, Anatoly; Timmins, Anthony Robert; Toia, Alberica; Trogolo, Stefano; Trombetta, Giuseppe; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ullaland, Kjetil; Uras, Antonio; Usai, Gianluca; Utrobicic, Antonija; Vala, Martin; Valencia Palomo, Lizardo; Van Der Maarel, Jasper; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Vanat, Tomas; Vande Vyvre, Pierre; Varga, Dezso; Diozcora Vargas Trevino, Aurora; Vargyas, Marton; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vauthier, Astrid; Vazquez Doce, Oton; Vechernin, Vladimir; Veen, Annelies Marianne; Velure, Arild; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Vickovic, Linda; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Villatoro Tello, Abraham; Vinogradov, Alexander; Vinogradov, Leonid; Virgili, Tiziano; Vislavicius, Vytautas; Viyogi, Yogendra; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Wagner, Boris; Wagner, Jan; Wang, Hongkai; Wang, Mengliang; Watanabe, Daisuke; Watanabe, Yosuke; Weber, Michael; Weber, Steffen Georg; Weiser, Dennis Franz; Wessels, Johannes Peter; Westerhoff, Uwe; Whitehead, Andile Mothegi; Wiechula, Jens; Wikne, Jon; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Willems, Guido Alexander; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Yalcin, Serpil; Yang, Ping; Yano, Satoshi; Yin, Zhongbao; Yokoyama, Hiroki; Yoo, In-Kwon; Yoon, Jin Hee; Yurchenko, Volodymyr; Zaborowska, Anna; Zaccolo, Valentina; Zaman, Ali; Zampolli, Chiara; Correia Zanoli, Henrique Jose; Zaporozhets, Sergey; Zardoshti, Nima; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Chunhui, Zhang; Zhang, Zuman; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zyzak, Maksym

    2017-01-01

    At sufficiently high temperature and energy density, nuclear matter undergoes a transition to a phase in which quarks and gluons are not confined: the quark–gluon plasma (QGP). Such an exotic state of strongly interacting quantum chromodynamics matter is produced in the laboratory in heavy nuclei high-energy collisions, where an enhanced production of strange hadrons is observed. Strangeness enhancement, originally proposed as a signature of QGP formation in nuclear collisions, is more pronounced for multi-strange baryons. Several effects typical of heavy-ion phenomenology have been observed in high-multiplicity proton–proton (pp) collisions, but the enhanced production of multi-strange particles has not been reported so far. Here we present the first observation of strangeness enhancement in high-multiplicity proton–proton collisions. We find that the integrated yields of strange and multi-strange particles, relative to pions, increases significantly with the event charged-particle multiplicity. The me...

  3. Anisotropic Flow of Strange Particles at SPS

    CERN Document Server

    Stefanek, Grzegorz; Anticic, T.; Baatar, B.; Barna, D.; Bartke, J.; Betev, L.; Białkowska, H.; Blume, C.; Boimska, B.; Botje, M.; Bracinik, J.; Bramm, R.; Bunčic, P.; Cerny, V.; Christakoglou, P.; Chung, P.; Chvala, O.; Cramer, J.G.; Csató, P.; Dinkelaker, P.; Eckardt, V.; Flierl, D.; Fodor, Z.; Foka, P.; Friese, V.; Gál, J.; Gazdzicki, M.; Genchev, V.; Georgopoulos, G.; Gładysz, E.; Grebieszkow, K.; Hegyi, S.; Höhne, C.; Kadija, K.; Karev, A.; Kikola, D.; Kliemant, M.; Kniege, S.; Kolesnikov, V.I.; Kornas, E.; Korus, R.; Kowalski, M.; Kraus, I.; Kreps, M.; Laszlo, A.; Lacey, R.; van Leeuwen, M.; Lévai, P.; Litov, L.; Lungwitz, B.; Makariev, M.; Malakhov, A.I.; Mateev, M.; Melkumov, G.L.; Mischke, A.; Mitrovski, M.; Molnár, J.; Mrówczynski, St.; Nicolic, V.; Pálla, G.; Panagiotou, A.D.; Panayotov, D.; Petridis, A.; Peryt, W.; Pikna, M.; Pluta, J.; Prindle, D.; Pühlhofer, F.; Renfordt, R.; Roland, C.; Roland, G.; Rybczynski, M.; Rybicki, A.; Sandoval, A.; Schmitz, N.; Schuster, T.; Seyboth, P.; Siklér, F.; Sitar, B.; Skrzypczak, E.; Slodkowski, M.; Stefanek, G.; Stock, R.; Strabel, C.; Ströbele, H.; Susa, T.; Szentpétery, I.; Sziklai, J.; Szuba, M.; Szymanski, P.; Trubnikov, V.; Varga, D.; Vassiliou, M.; Veres, G.I.; Vesztergombi, G.; Vranic, D.; Wetzler, A.; Włodarczyk, Z.; Wojtaszek, A.; Yoo, I.K.; Zimányi, J.; Stefanek, Grzegorz

    2006-01-01

    The elliptic flow for Lambda hyperons and K0s mesons was measured by the NA49 experiment in semicentral Pb+Pb collisions at 158A GeV. The standard method of correlating particles with an event plane has been used. Measurements of v2 near mid-rapidity are reported as a function of centrality, rapidity and transverse momentum. Elliptic flow of Lambda and K0s particles increases both with the impact parameter and with the transverse momentum. It is compared with v2 for pions and protons as well as with various model predictions. The NA49 results are compared with data from NA45/CERES and STAR experiments.

  4. Radio stars

    International Nuclear Information System (INIS)

    Hjellming, R.M.

    1976-01-01

    Any discussion of the radio emission from stars should begin by emphasizing certain unique problems. First of all, one must clarify a semantic confusion introduced into radio astronomy in the late 1950's when most new radio sources were described as radio stars. All of these early 'radio stars' were eventually identified with other galactic and extra-galactic objects. The study of true radio stars, where the radio emission is produced in the atmosphere of a star, began only in the 1960's. Most of the work on the subject has, in fact, been carried out in only the last few years. Because the real information about radio stars is quite new, it is not surprising that major aspects of the subject are not at all understood. For this reason this paper is organized mainly around three questions: what is the available observational information; what physical processes seem to be involved; and what working hypotheses look potentially fruitful. (Auth.)

  5. Shooting stars

    International Nuclear Information System (INIS)

    Maurette, M.; Hammer, C.

    1985-01-01

    A shooting star passage -even a star shower- can be sometimes easily seen during moonless black night. They represent the partial volatilization in earth atmosphere of meteorites or micrometeorites reduced in cosmic dusts. Everywhere on earth, these star dusts are searched to be gathered. This research made one year ago on the Greenland ice-cap is this article object; orbit gathering projects are also presented [fr

  6. Measurement of the strangeness spectral function and the mass of the strange quark in hadronic {tau} decays with the OPAL detector

    Energy Technology Data Exchange (ETDEWEB)

    Mader, W.

    2004-03-01

    Tau lepton decays with open strangeness in the final state are measured with the Opal detector at LEP to determine the strange hadronic spectral function of the {tau} lepton and the mass of the strange quark. The decays {tau}{sup -} {yields} (K{pi}){sup -}{nu}{sub {tau}}, (K{pi}{pi}){sup -}{nu}{sub {tau}} and (K{pi}{pi}{pi}){sup -}{nu}{sub {tau}} with final states consisting of neutral and charged kaons and pions, have been studied. The invariant mass distribution of 93.4% of these final states have been experimentally determined. Monte Carlo simulations have been used for the remaining 6.6% and for the strange final states including {eta} mesons. The reconstructed strange final states, corrected for resolution effects and detection efficiencies, yield the strange spectral function of the {tau} lepton. The moments of the spectral function and the ratio of strange to non-strange moments, which are important input parameters for theoretical analyses, are determined. Furthermore, the branching fractions B({tau}{sup -} {yields} K{sup -}{pi}{sup 0}{nu}{sub {tau}}) = (0.471 {+-} 0.064{sub stat} {+-} 0.021{sub sys})%, B({tau}{sup -} {yields} K{sup -}{pi}{sup +}{pi}{sup -}{nu}{sub {tau}}) = (0.415 {+-} 0.059{sub stat} {+-} 0.031{sub sys})% have been measured. From the CKM weighted difference of strange and non-strange spectral moments, the mass of the strange quark at the {tau} mass scale has been determined: m{sub s}(m{sub {tau}}{sup 2}) = (84 {+-} 14{sub exp} {+-} 6{sub V{sub us}} {+-} 17{sub theo}) MeV. Evolving this result to customary scales yields m{sub s}(1 GeV{sup 2}) = (111{sub -35}{sup +26}) MeV, m{sub s}(4 GeV{sup 2}) = (82{sub -25}{sup +19}) MeV. (orig.)

  7. Measurement of the strangeness spectral function and the mass of the strange quark in hadronic τ decays with the OPAL detector

    International Nuclear Information System (INIS)

    Mader, W.

    2004-03-01

    Tau lepton decays with open strangeness in the final state are measured with the Opal detector at LEP to determine the strange hadronic spectral function of the τ lepton and the mass of the strange quark. The decays τ - → (Kπ) - ν τ , (Kππ) - ν τ and (Kπππ) - ν τ with final states consisting of neutral and charged kaons and pions, have been studied. The invariant mass distribution of 93.4% of these final states have been experimentally determined. Monte Carlo simulations have been used for the remaining 6.6% and for the strange final states including η mesons. The reconstructed strange final states, corrected for resolution effects and detection efficiencies, yield the strange spectral function of the τ lepton. The moments of the spectral function and the ratio of strange to non-strange moments, which are important input parameters for theoretical analyses, are determined. Furthermore, the branching fractions B(τ - → K - π 0 ν τ ) = (0.471 ± 0.064 stat ± 0.021 sys )%, B(τ - → K - π + π - ν τ ) = (0.415 ± 0.059 stat ± 0.031 sys )% have been measured. From the CKM weighted difference of strange and non-strange spectral moments, the mass of the strange quark at the τ mass scale has been determined: m s (m τ 2 ) = (84 ± 14 exp ± 6 V us ± 17 theo ) MeV. Evolving this result to customary scales yields m s (1 GeV 2 ) = (111 -35 +26 ) MeV, m s (4 GeV 2 ) = (82 -25 +19 ) MeV. (orig.)

  8. Star Polymers.

    Science.gov (United States)

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  9. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Brorsen, Michael; Frigaard, Peter

    Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star.......Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star....

  10. Star Imager

    DEFF Research Database (Denmark)

    Madsen, Peter Buch; Jørgensen, John Leif; Thuesen, Gøsta

    1997-01-01

    The version of the star imager developed for Astrid II is described. All functions and features are described as well as the operations and the software protocol.......The version of the star imager developed for Astrid II is described. All functions and features are described as well as the operations and the software protocol....

  11. Measurement of the Strangeness Spectral Function and the Mass of the Strange Quark in Hadronic tau Decays with the OPAL Detector

    CERN Document Server

    Mader, Wolfgang Franz

    2004-01-01

    Tau lepton decays with open strangeness in the final state are measured with the Opal detector at LEP to determine the strange hadronic spectral function of the τ lepton and the mass of the strange quark. The decays τ −→ (Kπ) −ντ , (Kππ) −ντ and (Kπππ) −ντ with final states consisting of neutral and charged kaons and pions, have been studied. The invariant mass distribution of 93.4% of these final states have been experimentally determined. Monte Carlo simulations have been used for the remaining 6.6% and for the strange final states including η mesons. The reconstructed strange final states, corrected for resolution effects and detection efficiencies, yield the strange spectral function of the τ lepton. The moments of the spectral function and the ratio of strange to non-strange moments, which are important input parameters for theoretical analyses, are determined. Furthermore, the branching fractions B(τ − → K −π 0 ντ ) = (0.471 ± 0.064stat ± 0.021sys) % B(τ − → K ...

  12. Radio stars

    International Nuclear Information System (INIS)

    Hjellming, R.M.; Gibson, D.M.

    1985-01-01

    Studies of stellar radio emission became an important field of research in the 1970's and have now expanded to become a major area of radio astronomy with the advent of new instruments such as the Very Large Array in New Mexico and transcontinental telescope arrays. This volume contains papers from the workshop on stellar continuum radio astronomy held in Boulder, Colorado, and is the first book on the rapidly expanding field of radio emission from stars and stellar systems. Subjects covered include the observational and theoretical aspects of stellar winds from both hot and cool stars, radio flares from active double star systems and red dwarf stars, bipolar flows from star-forming regions, and the radio emission from X-ray binaries. (orig.)

  13. Properties of hybrid stars in an extended MIT bag model

    International Nuclear Information System (INIS)

    Bao Tmurbagan; Liu Guangzhou; Zhu Mingfeng

    2009-01-01

    The properties of hybrid stars are investigated in the framework of the relativistic mean field theory (RMFT) and an MIT bag model with density-dependent bag constant to describe the hadron phase (HP) and quark phase (QP), respectively. We find that the density-dependent B(ρ) decreases with baryon density ρ; this decrement makes the strange quark matter become more energetically favorable than ever; which makes the threshold densities of the hadron-quark phase transition lower than those of the original bag constant case. In this case, the hyperon degrees of freedom can not be considered. As a result, the equations of state of a star in the mixed phase (MP) become softer whereas those in the QP become stiffer, and the radii of the star obviously decrease. This indicates that the extended MIT bag model is more suitable to describe hybrid stars with small radii. (authors)

  14. Strange nucleon electromagnetic form factors from lattice QCD

    Science.gov (United States)

    Alexandrou, C.; Constantinou, M.; Hadjiyiannakou, K.; Jansen, K.; Kallidonis, C.; Koutsou, G.; Avilés-Casco, A. Vaquero

    2018-05-01

    We evaluate the strange nucleon electromagnetic form factors using an ensemble of gauge configurations generated with two degenerate maximally twisted mass clover-improved fermions with mass tuned to approximately reproduce the physical pion mass. In addition, we present results for the disconnected light quark contributions to the nucleon electromagnetic form factors. Improved stochastic methods are employed leading to high-precision results. The momentum dependence of the disconnected contributions is fitted using the model-independent z-expansion. We extract the magnetic moment and the electric and magnetic radii of the proton and neutron by including both connected and disconnected contributions. We find that the disconnected light quark contributions to both electric and magnetic form factors are nonzero and at the few percent level as compared to the connected. The strange form factors are also at the percent level but more noisy yielding statistical errors that are typically within one standard deviation from a zero value.

  15. Hot Strange Hadronic Matter in an Effective Model

    Science.gov (United States)

    Qian, Wei-Liang; Su, Ru-Keng; Song, Hong-Qiu

    2003-10-01

    An effective model used to describe the strange hadronic matter with nucleons, Λ-hyperons, and Ξ-hyperons is extended to finite temperature. The extended model is used to study the density, temperature, and strangeness fraction dependence of the effective masses of baryons in the matter. The thermodynamical quantities, such as free energy and pressure, as well as the equation of state of the matter, are given. The project supported in part by National Natural Science Foundation of China under Grant Nos. 10075071, 10047005, 19947001, 19975010, and 10235030, and the CAS Knowledge Innovation Project No. KJCX2-N11. Also supported by the State Key Basic Research Development Program under Grant No. G200077400 and the Exploration Project of Knowledge Innovation Program of the Chinese Academy of Sciences

  16. Torus-doubling process via strange nonchaotic attractors

    International Nuclear Information System (INIS)

    Mitsui, Takahito; Uenohara, Seiji; Morie, Takashi; Horio, Yoshihiko; Aihara, Kazuyuki

    2012-01-01

    Torus-doubling bifurcations typically occur only a finite number of times. It has been assumed that torus-doubling bifurcations in quasiperiodically forced systems are interrupted by the appearance of strange nonchaotic attractors (SNAs). In the present Letter, we study a quasiperiodically forced noninvertible map and report the occurrence of a torus-doubling process via SNAs. The mechanism of this process is numerically clarified. Furthermore, this process is experimentally demonstrated in a switched-capacitor integrated circuit. -- Highlights: ► We report the occurrence of a torus-doubling process via strange nonchaotic attractors (SNAs). ► The process consists of the gradual fractalization of a torus and the Heagy–Hammel transition. ► The torus-doubling process via SNAs is also experimentally demonstrated in an electronic circuit.

  17. Strange attractor of Henon map and its basin

    Institute of Scientific and Technical Information of China (English)

    曹永罗

    1995-01-01

    In this paper, Henon map is considered. For a positive measure set of parameters (a, b), we construct a trapping region G of topologically transitive strange attractor Aa,b for Ta,b, and prove that Aa,b= ∩n≥0Ta,bnG, and the basin B(Aa,b) of Aa,b is exactly the union of domain whose boundary is contained in w5(p) ∪wu(p) and ws(p). Therefore, that the conjecture posed by Benedicks and Carleson about the basin of strange attactor is true is proved. Furthermore, B(Aa,b) is simply connected and path-connected, w4(p2) is contained in the attainable boundary set of B(Aa,b) (where p2 is another hyperbolic fixed point of Ta,b).

  18. Strange attractors in weakly turbulent Couette-Taylor flow

    Science.gov (United States)

    Brandstater, A.; Swinney, Harry L.

    1987-01-01

    An experiment is conducted on the transition from quasi-periodic to weakly turbulent flow of a fluid contained between concentric cylinders with the inner cylinder rotating and the outer cylinder at rest. Power spectra, phase-space portraits, and circle maps obtained from velocity time-series data indicate that the nonperiodic behavior observed is deterministic, that is, it is described by strange attractors. Various problems that arise in computing the dimension of strange attractors constructed from experimental data are discussed and it is shown that these problems impose severe requirements on the quantity and accuracy of data necessary for determining dimensions greater than about 5. In the present experiment the attractor dimension increases from 2 at the onset of turbulence to about 4 at a Reynolds number 50-percent above the onset of turbulence.

  19. Quark-flavor mixing and the nucleon strangeness form factors

    International Nuclear Information System (INIS)

    Ito, H.

    1995-01-01

    We have calculated the strangeness form factors of the nucleon G E s (Q), G M s (Q) and G A s (Q) and the electromagnetic form factors G E N (Q) as well, by using a relativistic constituent quark model of the nucleon wave function on the light-cone. Octet of Goldstone bosons (π, K, η) are assumed to induce the SU flavor mixing among the light constituent quarks; d-→K+s →d for example, and this mechanism induces the strangeness content in the nucleon. To calculate the meson-loop corrections to the electroweak couplings of constituent quarks, we have employed two models of the quark-meson vertex; (1) composite model of the Goldstone bosons (2) and (3) chiral quark Lagrangian. The loop momenta are regulated in a gauge-invariant way for both models

  20. Strangeness in nuclear matter at DAΦNE

    International Nuclear Information System (INIS)

    Gianotti, P.

    1998-01-01

    The low energy kaons from the φ meson produced at DAΦNE offer a unique opportunity to study strangeness in nuclear matter. The interaction of kaons with hadronic matter can be investigated at DAΦNE using three main approaches: study of hypernuclei production and decay, kaons scattering on nucleons, kaonic atoms formation. These studies explore kaon-nucleon and hyperon-nucleon forces at very low energy, the nuclear shell model in presence of strangeness quantum number and eventual quarks deconfinement phenomena. The experiments devoted to study this physical program at DAΦNE are FINUDA and DEAR. The physics topics of both experiments are illustrated together with a detailed descriptions of the two detectors

  1. A strange familiarity? Place perceptions among the globally mobile

    DEFF Research Database (Denmark)

    Pristed Nielsen, Helene; Faber, Stine Thidemann

    2014-01-01

    How do globally mobile people perceive and make sense of a new place in which they have to create an everyday life for themselves? And how may their place perception be communicated through photographs? These are the questions around which this article revolves. The visual material discussed...... of strangeness and familiarity occur along unexpected lines of difference and similarity depending on the embodied positionality of the involved participants....

  2. Anomalies, symmetries and strangeness content of the proton

    Indian Academy of Sciences (India)

    The matrix elements of the operators of strange quark fields s ¯ s where is 1 or 5 between a proton state is calculated. The sigma term is found to be ≈ 41 MeV and the (3) singlet axial matrix element is found to be ≈ 0.22, both in agreement with experiment. The sigma term is found using the trace anomaly, ...

  3. LHCb: Prospect for rare strange decays at LHCb

    CERN Multimedia

    Marin Benito, C

    2014-01-01

    Prospects on rare strange decays at LHCb are presented. The latest results from the K_s \\to \\mu \\mu search are reported, together with the future prospects for this decay. A search for K_s \\to \\pi^0 \\mu \\mu, a K^+ mass measurement, a search for K_s \\to 4 \\el and a search for \\Sigma^+ \\to p\\mu\\mu are also presented.

  4. Diffractive production of charmed strange mesons by neutrinos and antineutrinos

    Science.gov (United States)

    Asratyan, A. E.; Aderholz, M.; Ammosov, V. V.; Burkot, W.; Clayton, E. F.; Coghen, T.; Erriquez, O.; Gapienko, G. S.; Gapienko, V. A.; Guy, J.; Hantke, D.; Jones, G. T.; Kaftanov, V. S.; Katz, U. F.; Kern, J.; Korotkov, V. A.; Krutchinin, S. P.; Kubantsev, M. A.; Marage, P.; Miller, D. B.; Mobayyen, M. M.; Morrison, D. R. O.; Neveu, M.; Sacton, J.; Schmitz, N.; Varvell, K.; Venus, W.; Wittek, W.; Zaetz, V. G.

    1993-03-01

    The diffractive production of charmed strange D {s/*} and possibly D s mesons by neutrinos and antineutrinos on nucleons in hydrogen, deuterium and neon targets is observed. The slope parameter of the t distribution is 3.3±0.8 (GeV)-2. The production rate per charged current neutrino interaction with an isoscalar target times the D{s/+}→φτ+ branching fraction is (1.03±0.27)×10-4.

  5. Diffractive production of charmed strange mesons by neutrinos and antineutrinos

    International Nuclear Information System (INIS)

    Asratyan, A.E.; Kaftanov, V.S.; Krutchinin, S.P.; Kubantsev, M.A.; Aderholz, M.; Hantke, D.; Katz, U.F.; Kern, J.; Schmitz, N.; Wittek, W.; Ammosov, V.V.; Gapienko, G.S.; Gapienko, V.A.; Korotkov, V.A.; Zaetz, V.G.; Burkot, W.; Coghen, T.; Clayton, E.F.; Miller, D.B.; Mobayyen, M.M.; Erriquez, O.; Guy, J.; Venus, W.; Jones, G.T.; Varvell, K.; Marage, P.; Sacton, J.; Morrison, D.R.O.; Neveu, M.

    1993-01-01

    The diffractive production of charmed strange D s * and possibly D s mesons by neutrinos and antineutrinos on nucleons in hydrogen, deuterium and neon targets is observed. The slope parameter of the t distribution is 3.3±0.8 (GeV) -2 . The production rate per charged current neutrino interaction with an isoscalar target times the D s + →φπ + branching fraction is (1.03±0.27)x10 -4 . (orig.)

  6. Overview of the electromagnetic production of strange mesons at MAMI

    Czech Academy of Sciences Publication Activity Database

    Achenbach, P.; Rodriguez, M. G.; Tsukada, K.; Gayoso, C. A.; Böhm, R.; Borodina, O.; Bosnar, D.; Bozkurt, V.; Bydžovský, Petr; Debenjak, L.; Distler, M. O.; Esser, A.; Friscic, I.; Fujii, Y.; Gogami, T.; Hashimoto, O.; Hirose, S.; Kanda, H.; Kaneta, M.; Kim, E.; Margaryan, A.; Merkel, H.; Müller, U.; Nagao, S.; Nakamura, S. N.; Pochodzalla, J.; Rappold, C.; Reinhold, J.; Saito, T. R.; Lorente, A.S.; Majos, S. S.; Schlimme, B. S.; Schoth, M.; Schultz, F.; Sfienti, C.; Sirca, S.; Tang, L.; Thiel, M.

    2013-01-01

    Roč. 914, SEP (2013), s. 41-50 ISSN 0375-9474 R&D Projects: GA ČR(CZ) GAP203/12/2126 Institutional support: RVO:61389005 Keywords : strangeness reactions * Kaon electro-production * missing mass spectroscopy * structure functions Subject RIV: BE - Theoretical Physics Impact factor: 2.499, year: 2013 http://www.sciencedirect.com/science/article/pii/S0375947413000304

  7. Strangeness-changing vector currents in τ-lepton decays

    International Nuclear Information System (INIS)

    Bednyakov, V.A.; Osipov, A.A.

    1992-01-01

    The Cabibbo suppressed τ-lepton decays into a kaon and a non-strange pseudoscalar meson have been investigated in the U(3)-version of the superconducting quark model with allowance for ΦA-mixing. The total and differential widths of four τ-lepton decays were obtained. The number of these decays per year at the c-τ-factory was calculated. 6 refs.; 4 figs.; 2 tabs

  8. Does Kepler unveil the mystery of the Blazhko effect? First detection of period doubling in Kepler Blazhko RR Lyrae stars

    DEFF Research Database (Denmark)

    Szabó, R.; Kollath, Z.; Molnár, L.

    2010-01-01

    -doubling bifurcation in our non-linear RR Lyrae models computed by the Florida-Budapest hydrocode. This enabled us to trace the origin of this instability in RR Lyrae stars to a resonance, namely a 9:2 resonance between the fundamental mode and a high-order (ninth) radial overtone showing strange-mode characteristics...

  9. Another Possibility for Boyajian's Star

    Science.gov (United States)

    Kohler, Susanna

    2017-07-01

    2017]Foukal recognized that this phenomenon may also provide an explanation for Boyajians star. He modeled how this might occur for Boyajians star, demonstrating that if its flux is somehow blocked from reaching the surface and stored in a shallow convective zone, this can account for the 20% dips seen in the stars light curve.In addition, these sporadic flux-blocking events would cause Boyajians star to constantly be relaxing from the post-blockage enhanced luminosity. This decay which occurs at rates of 0.11% brightness per year for convective-zone depths of tens of thousands of kilometers would nicely account for the long-term, gradual dimming observed.Whats blocking the flux? Foukal postulates a few options, including magnetic activity (as with the Sun), differential rotation, sporadic changes in photospheric abundances, and simply random variation in convective efficiency.Strangely UniqueBoyajians stars flux in May and June shows some brand new dips. Note that the team now names them! [Tabetha Boyajian and team]So why have we only found one star with light curves like Boyajians? If these are inherently natural processes in the star, we would expect to have seen more than one such object. This may be selection effect Boyajians star lies at the hot end of the range of stars that Kepler observes or it may be that the star is reaching the end of its convective lifetime.Until we discover more cases, the best we can hope for is more data from Boyajians star itself. Conveniently, it has continued to keep us on our toes, with new dips in May and June. Perhaps our continued observations will finally reveal the answer to this mystery.CitationPeter Foukal 2017 ApJL 842 L3. doi:10.3847/2041-8213/aa740f

  10. Symbiotic stars

    International Nuclear Information System (INIS)

    Kafatos, M.; Michalitsianos, A.G.

    1984-01-01

    Among the several hundred million binary systems estimated to lie within 3000 light years of the solar system, a tiny fraction, no more than a few hundred, belong to a curious subclass whose radiation has a wavelength distribution so peculiar that it long defied explanation. Such systems radiate strongly in the visible region of the spectrum, but some of them do so even more strongly at both shorter and longer wavelengths: in the ultraviolet region and in the infrared and radio regions. This odd distribution of radiation is best explained by the pairing of a cool red giant star and an intensely hot small star that is virtually in contact with its larger companion. Such objects have become known as symbiotic stars. On photographic plate only the giant star can be discerned, but evidence for the existence of the hot companion has been supplied by satellite-born instruments capable of detecting ultraviolet radiation. The spectra of symbiotic stars indicate that the cool red giant is surrounded by a very hot ionized gas. Symbiotic stars also flared up in outbursts indicating the ejection of material in the form of a shell or a ring. Symbiotic stars may therefore represent a transitory phase in the evolution of certain types of binary systems in which there is substantial transfer of matter from the larger partner to the smaller

  11. Strangeness as a probe to baryon-rich QCD matter at NICA

    Energy Technology Data Exchange (ETDEWEB)

    Fukushima, Kenji [The University of Tokyo, Department of Physics, Bunkyo-ku, Tokyo (Japan)

    2016-08-15

    We elucidate a prospect of strangeness fluctuation measurements in the heavy-ion collision at NICA energies. The strangeness fluctuation is sensitive to quark deconfinement. At the same time strangeness has a strong correlation with the baryon number under the condition of vanishing net strangeness, which leads to an enhancement of Λ{sup 0}, Ξ{sup 0}, Ξ{sup -}, and K{sup +} at high baryon density. The baryon density is maximized around the NICA energies, and strangeness should be an ideal probe to investigate quark deconfinement phenomena of baryon-rich QCD matter created at NICA. We also utilize the hadron resonance gas model to estimate a mixed fluctuation of strangeness and baryon number. (orig.)

  12. The strange quark contribution to the neutron electric dipole moment in multi-Higgs doublet models

    International Nuclear Information System (INIS)

    He, Xiao Gang; McKeller, H.J.; Pakvasa, S.

    1990-09-01

    The strange quark contribution to the neutron electric dipole moment was studied and compared with other contributions in multi-Higgs doublet models. It was found that the strange quark contribution is significant because the strange quark color dipole moment is larger than that of the down (up) quark by a factor m s /m d (m s /m u ). In the case of neutral Higgs it can be the dominant contribution to the neutron electric dipole moment. 18 refs

  13. Star formation

    International Nuclear Information System (INIS)

    Woodward, P.R.

    1978-01-01

    Theoretical models of star formation are discussed beginning with the earliest stages and ending in the formation of rotating, self-gravitating disks or rings. First a model of the implosion of very diffuse gas clouds is presented which relies upon a shock at the edge of a galactic spiral arm to drive the implosion. Second, models are presented for the formation of a second generation of massive stars in such a cloud once a first generation has formed. These models rely on the ionizing radiation from massive stars or on the supernova shocks produced when these stars explode. Finally, calculations of the gravitational collapse of rotating clouds are discussed with special focus on the question of whether rotating disks or rings are the result of such a collapse. 65 references

  14. Virtual meson cloud of the nucleon and intrinsic strangeness and charm

    International Nuclear Information System (INIS)

    Navarra, F.S.; Nielsen, M.; Duraes, F.O.; Barz, L.L.; Paiva, S.

    1996-09-01

    We have applied the Meson Cloud Model (MCM) to calculate the charm and strange antiquark distribution in the nucleon. The resulting distribution, in the case of charm, is very similar to the intrinsic charm momentum distribution in the nucleon. This seems to corroborate the hypothesis that the intrinsic charm is in the cloud and, at the same time, explains why other calculations with the MCM involving strange quark distributions fail in reproducing the low x region data. From the intrinsic strange distribution in the nucleon we have extracted the strangeness radius of the nucleon, which is in agreement with other meson cloud calculations. (author). 28 refs., 4 figs

  15. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Frigaard, Peter

    Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star....

  16. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Andersen, Thomas Lykke

    Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star....

  17. STARS no star on Kauai

    International Nuclear Information System (INIS)

    Jones, M.

    1993-01-01

    The island of Kuai, home to the Pacific Missile Range Facility, is preparing for the first of a series of Star Wars rocket launches expected to begin early this year. The Strategic Defense Initiative plans 40 launches of the Stategic Target System (STARS) over a 10-year period. The focus of the tests appears to be weapons and sensors designed to combat multiple-warhead ICBMs, which will be banned under the START II Treaty that was signed in January. The focus of this article is to express the dubious value of testing the STARS at a time when their application will not be an anticipated problem

  18. Flare stars

    International Nuclear Information System (INIS)

    Nicastro, A.J.

    1981-01-01

    The least massive, but possibly most numerous, stars in a galaxy are the dwarf M stars. It has been observed that some of these dwarfs are characterized by a short increase in brightness. These stars are called flare stars. These flare stars release a lot of energy in a short amount of time. The process producing the eruption must be energetic. The increase in light intensity can be explained by a small area rising to a much higher temperature. Solar flares are looked at to help understand the phenomenon of stellar flares. Dwarfs that flare are observed to have strong magnetic fields. Those dwarf without the strong magnetic field do not seem to flare. It is believed that these regions of strong magnetic fields are associated with star spots. Theories on the energy that power the flares are given. Astrophysicists theorize that the driving force of a stellar flare is the detachment and collapse of a loop of magnetic flux. The mass loss due to stellar flares is discussed. It is believed that stellar flares are a significant contributor to the mass of interstellar medium in the Milky Way

  19. Fighting discrimination.

    Science.gov (United States)

    Wientjens, Wim; Cairns, Douglas

    2012-10-01

    In the fight against discrimination, the IDF launched the first ever International Charter of Rights and Responsibilities of People with Diabetes in 2011: a balance between rights and duties to optimize health and quality of life, to enable as normal a life as possible and to reduce/eliminate the barriers which deny realization of full potential as members of society. It is extremely frustrating to suffer blanket bans and many examples exist, including insurance, driving licenses, getting a job, keeping a job and family affairs. In this article, an example is given of how pilots with insulin treated diabetes are allowed to fly by taking the responsibility of using special blood glucose monitoring protocols. At this time the systems in the countries allowing flying for pilots with insulin treated diabetes are applauded, particularly the USA for private flying, and Canada for commercial flying. Encouraging developments may be underway in the UK for commercial flying and, if this materializes, could be used as an example for other aviation authorities to help adopt similar protocols. However, new restrictions implemented by the new European Aviation Authority take existing privileges away for National Private Pilot Licence holders with insulin treated diabetes in the UK. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  20. Symbiotic stars

    Science.gov (United States)

    Kafatos, M.; Michalitsianos, A. G.

    1984-01-01

    The physical characteristics of symbiotic star systems are discussed, based on a review of recent observational data. A model of a symbiotic star system is presented which illustrates how a cool red-giant star is embedded in a nebula whose atoms are ionized by the energetic radiation from its hot compact companion. UV outbursts from symbiotic systems are explained by two principal models: an accretion-disk-outburst model which describes how material expelled from the tenuous envelope of the red giant forms an inwardly-spiralling disk around the hot companion, and a thermonuclear-outburst model in which the companion is specifically a white dwarf which superheats the material expelled from the red giant to the point where thermonuclear reactions occur and radiation is emitted. It is suspected that the evolutionary course of binary systems is predetermined by the initial mass and angular momentum of the gas cloud within which binary stars are born. Since red giants and Mira variables are thought to be stars with a mass of one or two solar mass, it is believed that the original cloud from which a symbiotic system is formed can consist of no more than a few solar masses of gas.

  1. Unlocking the secrets of white dwarf stars

    CERN Document Server

    Van Horn, Hugh M

    2015-01-01

    White dwarfs, each containing about as much mass as our Sun but packed into a volume about the size of Earth, are the endpoints of evolution for most stars. Thousands of these faint objects have now been discovered, though only a century ago only three were known. They are among the most common stars in the Milky Way Galaxy, and they have become important tools in understanding the universe. Yet a century ago only three white dwarfs were known.   The existence of these stars completely baffled the scientists of the day, and solving the mysteries of these strange objects required revolutionary advances in science and technology, including the development of quantum physics, the construction and utilization of large telescopes, the invention of the digital computer, and the ability to make astronomical observations from space.   This book tells the story of the growth in our understanding of white dwarf stars, set within the context of the relevant scientific and technological advances. Part popular science, ...

  2. Discrimination and Anti-discrimination in Denmark

    DEFF Research Database (Denmark)

    Olsen, Tore Vincents

    The purpose of this report is to describe and analyse Danish anti-discrimination legislation and the debate about discrimination in Denmark in order to identify present and future legal challenges. The main focus is the implementation of the EU anti-discrimination directives in Danish law...

  3. Connected, disconnected and strange quark contributions to HVP

    International Nuclear Information System (INIS)

    Bijnens, Johan; Relefors, Johan

    2016-01-01

    We calculate all neutral vector two-point functions in Chiral Perturbation Theory (ChPT) to two-loop order and use these to estimate the ratio of disconnected to connected contributions as well as contributions involving the strange quark. We extend the ratio of −1/10 derived earlier in two flavour ChPT at one-loop order to a large part of the higher order contributions and discuss corrections to it. Our final estimate of the ratio disconnected to connected is negative and a few % in magnitude.

  4. Strangeness of the nucleon from lattice quantum chromodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Alexandrou, Constantia [The Cyprus Institute, Nicosia (Cyprus). Computation-based Science and Technology Research Center (CaSToRC); Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; Constantinou, Martha; Hadjiyiannakou, Kyriakos [Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; Dinter, Simon; Drach, Vincent [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Jansen, Karl [Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Koutsou, Giannis; Vaquero, Alejandro [The Cyprus Institute, Nicosia (Cyprus). Computation-based Science and Technology Research Center (CaSToRC); Collaboration: ETM Collaboration

    2013-10-15

    We present a non-perturbative calculation of the strangeness of the nucleon y{sub N} within the framework of lattice QCD. This observable is known to be an important cornerstone to interpret results from direct dark matter detection experiments. We perform a lattice computation for y{sub N} with an analysis of systematic effects originating from discretization, finite size, chiral extrapolation and excited state effects leading to a value of y{sub N}=0.135(46) which turns out to be rather small. As a main result of our work, we demonstrate that the error for y{sub N} is dominated by systematic uncertainties.

  5. Connected, disconnected and strange quark contributions to HVP

    Energy Technology Data Exchange (ETDEWEB)

    Bijnens, Johan; Relefors, Johan [Department of Astronomy and Theoretical Physics, Lund University,Sölvegatan 14A, SE 223-62 Lund (Sweden)

    2016-11-14

    We calculate all neutral vector two-point functions in Chiral Perturbation Theory (ChPT) to two-loop order and use these to estimate the ratio of disconnected to connected contributions as well as contributions involving the strange quark. We extend the ratio of −1/10 derived earlier in two flavour ChPT at one-loop order to a large part of the higher order contributions and discuss corrections to it. Our final estimate of the ratio disconnected to connected is negative and a few % in magnitude.

  6. Connected, disconnected and strange quark contributions to HVP

    Science.gov (United States)

    Bijnens, Johan; Relefors, Johan

    2016-11-01

    We calculate all neutral vector two-point functions in Chiral Perturbation Theory (ChPT) to two-loop order and use these to estimate the ratio of disconnected to connected contributions as well as contributions involving the strange quark. We extend the ratio of -1/10 derived earlier in two flavour ChPT at one-loop order to a large part of the higher order contributions and discuss corrections to it. Our final estimate of the ratio disconnected to connected is negative and a few % in magnitude.

  7. Strange-particle production via the weak interaction

    International Nuclear Information System (INIS)

    Adera, G. B.; Van Der Ventel, B. I. S.; Niekerk, D. D. van; Mart, T.

    2010-01-01

    The differential cross sections for the neutrino-induced weak charged current production of strange particles in the threshold energy region are presented. The general representation of the weak hadronic current is newly developed in terms of eighteen unknown invariant amplitudes to parametrize the hadron vertex. The Born-term approximation is used for the numerical calculations in the framework of the Cabibbo theory and SU(3) symmetry. For unpolarized octet baryons four processes are investigated, whereas in the case of polarized baryons only one process is chosen to study the sensitivity of the differential cross section to the various polarizations of the initial-state nucleon and the final-state hyperon.

  8. 1-4 Strangeness Production in Antiproton Induced Nuclear Reactions.

    Institute of Scientific and Technical Information of China (English)

    Feng; Zhaoqing[1

    2014-01-01

    More localized energy deposition is able to be produced in antiproton-nucleus collisions in comparison withheavy-ion collisions due to annihilation reactions. Searching for the cold quark-gluon plasma (QGP) with antiprotonbeamshas been considered as a hot topic both in experiments and in theretical calculations over the past severaldecades. Strangeness production and hypernucleus formation in antiproton-induced nuclear reactions are importancein exploring the hyperon (antihyperon)-nucleon (HN) potential and the antinucleon-nucleon interaction, whichhave been hot topics in the forthcoming experiments at PANDA in Germany.

  9. STRANGE ATTRACTORS ON PSEUDOSPECTRAL SOLUTIONS FOR DISSIPATIVE ZAKHAROV EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    马书清; 常谦顺

    2004-01-01

    In this paper, the pseudospcctral method to solve the dissipative Zakharov equations is used. Its convergence is proved by priori estinates. The existence of the global attractors and the estimates of dimension are presented. A class of steady state solutions is also disscussed. The numerical results show that if the steady state solutions satisfy some special conditions, they become unstable and limit cycles and strange attractors will occur for very small perturbations.The largest Lyapunov exponent and analysis of the lincarized system are applied to explain these phenomena.

  10. Influence of rescattering on the spectra of strange particles

    International Nuclear Information System (INIS)

    David, C.; Hartnack, C.; Kerveno, M.; Le Pallec, J.Ch.; Aichelin, J.

    1996-11-01

    Applying a new method of rescattering based on neural network technique the influence of rescattering on the spectra of strange particles produced in heavy ion reactions is studied. A comparison of our calculations for the system Ni(1.93 A GeV)+Ni with recent data of the FOPI collaboration is presented. It is found that even for this small system rescattering changes the observables considerably but does not invalidate the role of the kaons as a messenger from the high density zone. (K.A.)

  11. Precise Determination of the Strangeness Magnetic Moment of the Nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Leinweber, D B; Boinepalli, S; Cloet, I C; Thomas, A W; Williams, A G; Young, R D; Zanotti, J M; Zhang, J B

    2005-06-01

    By combining the constraints of charge symmetry with new chiral extrapolation techniques and recent low mass lattice QCD simulations of the individual quark contributions to the magnetic moments of the nucleon octet, we obtain a precise determination of the strange magnetic moment of the proton. The result, namely G{sub M}{sup s} = -0.051 +/- 0.021 mu{sub N}, is consistent with the latest experimental measurements but an order of magnitude more precise. This poses a tremendous challenge for future experiments.

  12. Some statistical properties of strange attractors: engineering view

    International Nuclear Information System (INIS)

    Mijangos, M; Kontorovich, V; Aguilar-Torrentera, J

    2008-01-01

    In this paper, the statistical characterization of strange attractors is investigated via the so-called 'model distribution' approach. It is shown that in order to calculate the first four cumulants, which are necessary to create a model distribution of kurtosis approximation, a systematic method for the calculus of the variance needs to be considered. Correspondently, an analytical method based on the Kolmogorov-Sinai (K-S) entropy for variance approximation is herein proposed. The methodology is of interest for its application in the statistical analysis of chaotic systems that model physical phenomena found in some areas of electrical (communication) engineering

  13. Strangeness Suppression of qq ¯ Creation Observed in Exclusive Reactions

    Science.gov (United States)

    Mestayer, M. D.; Park, K.; Adhikari, K. P.; Aghasyan, M.; Pereira, S. Anefalos; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; Deur, A.; Djalali, C.; Doughty, D.; Dupre, R.; Alaoui, A. El; Fassi, L. El; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fleming, J. A.; Forest, T. A.; Garillon, B.; Garçon, M.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guegan, B.; Guidal, M.; Hakobyan, H.; Hanretty, C.; Hattawy, M.; Holtrop, M.; Hughes, S. M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Jiang, H.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Koirala, S.; Kubarovsky, V.; Kuleshov, S. V.; Lenisa, P.; Levine, W. I.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Mayer, M.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moody, C. I.; Moutarde, H.; Movsisyan, A.; Camacho, C. Munoz; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Peng, P.; Phelps, W.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Rimal, D.; Ripani, M.; Rizzo, A.; Rosner, G.; Roy, P.; Sabatié, F.; Saini, M. S.; Schott, D.; Schumacher, R. A.; Simonyan, A.; Sokhan, D.; Strauch, S.; Sytnik, V.; Tang, W.; Tian, Ye; Ungaro, M.; Vernarsky, B.; Vlassov, A. V.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

    2014-10-01

    We measured the ratios of electroproduction cross sections from a proton target for three exclusive meson-baryon final states: ΛK+, pπ0, and nπ+, with the CLAS detector at Jefferson Lab. Using a simple model of quark hadronization, we extract qq ¯ creation probabilities for the first time in exclusive two-body production, in which only a single qq ¯ pair is created. We observe a sizable suppression of strange quark-antiquark pairs compared to nonstrange pairs, similar to that seen in high-energy production.

  14. Strangeness suppression of qq creation observed in exclusive reactions.

    Science.gov (United States)

    Mestayer, M D; Park, K; Adhikari, K P; Aghasyan, M; Pereira, S Anefalos; Ball, J; Battaglieri, M; Batourine, V; Bedlinskiy, I; Biselli, A S; Boiarinov, S; Briscoe, W J; Brooks, W K; Burkert, V D; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Contalbrigo, M; Cortes, O; Crede, V; D'Angelo, A; Dashyan, N; De Vita, R; Deur, A; Djalali, C; Doughty, D; Dupre, R; El Alaoui, A; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fleming, J A; Forest, T A; Garillon, B; Garçon, M; Ghandilyan, Y; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Golovatch, E; Gothe, R W; Griffioen, K A; Guegan, B; Guidal, M; Hakobyan, H; Hanretty, C; Hattawy, M; Holtrop, M; Hughes, S M; Hyde, C E; Ilieva, Y; Ireland, D G; Jiang, H; Jo, H S; Joo, K; Keller, D; Khandaker, M; Kim, A; Kim, W; Koirala, S; Kubarovsky, V; Kuleshov, S V; Lenisa, P; Levine, W I; Livingston, K; Lu, H Y; MacGregor, I J D; Mayer, M; McKinnon, B; Meyer, C A; Mirazita, M; Mokeev, V; Montgomery, R A; Moody, C I; Moutarde, H; Movsisyan, A; Camacho, C Munoz; Nadel-Turonski, P; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Pappalardo, L L; Paremuzyan, R; Peng, P; Phelps, W; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Protopopescu, D; Puckett, A J R; Raue, B A; Rimal, D; Ripani, M; Rizzo, A; Rosner, G; Roy, P; Sabatié, F; Saini, M S; Schott, D; Schumacher, R A; Simonyan, A; Sokhan, D; Strauch, S; Sytnik, V; Tang, W; Tian, Ye; Ungaro, M; Vernarsky, B; Vlassov, A V; Voskanyan, H; Voutier, E; Walford, N K; Watts, D P; Wei, X; Weinstein, L B; Wood, M H; Zachariou, N; Zhang, J; Zhao, Z W; Zonta, I

    2014-10-10

    We measured the ratios of electroproduction cross sections from a proton target for three exclusive meson-baryon final states: ΛK(+), pπ(0), and nπ(+), with the CLAS detector at Jefferson Lab. Using a simple model of quark hadronization, we extract qq creation probabilities for the first time in exclusive two-body production, in which only a single qq pair is created. We observe a sizable suppression of strange quark-antiquark pairs compared to nonstrange pairs, similar to that seen in high-energy production.

  15. Dark stars

    DEFF Research Database (Denmark)

    Maselli, Andrea; Pnigouras, Pantelis; Nielsen, Niklas Grønlund

    2017-01-01

    to the formation of compact objects predominantly made of dark matter. Considering both fermionic and bosonic (scalar φ4) equations of state, we construct the equilibrium structure of rotating dark stars, focusing on their bulk properties and comparing them with baryonic neutron stars. We also show that these dark......Theoretical models of self-interacting dark matter represent a promising answer to a series of open problems within the so-called collisionless cold dark matter paradigm. In case of asymmetric dark matter, self-interactions might facilitate gravitational collapse and potentially lead...... objects admit the I-Love-Q universal relations, which link their moments of inertia, tidal deformabilities, and quadrupole moments. Finally, we prove that stars built with a dark matter equation of state are not compact enough to mimic black holes in general relativity, thus making them distinguishable...

  16. Consideration of the vacuum of QCD in a composite quark model. Strange hadrons

    International Nuclear Information System (INIS)

    Dorokhov, A.E.; Kochelev, N.I.

    1986-01-01

    The method of inclusion of QCD vacuum condensates within the quark composite model is generalized to the case of hadrons containing strange quarks. The mass formula for such hadrons is obtained. The mass of strange quark is defined by analysing the energy spectrum of hadron ground states. The mixing angles of pseudoscalar mesons are estimated

  17. The strange 0++ and 2++ radial excitations: A review of LASS data

    International Nuclear Information System (INIS)

    Aston, D.; Bienz, T.; Bird, F.; Dunwoodie, W.; Johnson, W.B.; Kunz, P.; Kwon, Y.; Leith, D.W.G.S.; Levinson, L.; Ratcliff, B.N.; Rensing, P.; Schultz, D.; Shapiro, S.; Sinervo, P.K.; Tarnopolsky, G.; Toge, N.; Waite, A.; Williams, S.; Awaji, N.; Fujii, K.; Hayashii, H.; Iwata, S.; Kajikawa, R.; Matsui, T.; Miyamoto, A.; Ozaki, H.; Pak, C.O.; Shimomura, T.; Sugiyama, A.; Suzuki, S.; Tauchi, T.; D'Amore, J.; Endorf, R.; Martinez, J.; Meadows, B.T.; Nussbaum, M.; Ukai, K.

    1991-10-01

    The experimental status of the strange 0 ++ and 2 ++ mesons is briefly reviewed and compared with expectations from the quark model. The results are taken from a high statistics study of strange mesons produced in LASS by an 11 GeV/c K - beam. 13 refs., 8 figs., 1 tab

  18. Cross-Curricular Teaching Going Forward: A View from "Strange Fruit"

    Science.gov (United States)

    Esteve-Faubel, José-María; Martin, Tania Josephine; Junda, Mary Ellen

    2018-01-01

    "Strange Fruit," a song popularized by Billie Holiday in 1939, paints a gruesome picture of racial violence suffered by former African-American slaves following Reconstruction, 1863-1877 (Foner, 2011). While many scholars have analyzed the lyrics of "Strange Fruit", research that focuses on young people's reaction to the song…

  19. Aspects of strangeness production with 15 -- 30 GeV proton beams

    International Nuclear Information System (INIS)

    Dover, C.B.

    1992-04-01

    We discuss the spectrum of physics questions related to strangeness which could be addressed with a 15--30 GeV proton storage ring. We focus on various aspects of strangeness production, including hyperon production in pp collisions, studies of hyperon-nucleon scattering, production of hyper-fragments in p-nucleus collisions, and hyperon spin observables in inclusive production

  20. Universal scaling of strange particle pT spectra in pp collisions

    Science.gov (United States)

    Yang, Liwen; Wang, Yanyun; Hao, Wenhui; Liu, Na; Du, Xiaoling; Zhang, Wenchao

    2018-04-01

    As a complementary study to that performed on the transverse momentum (pT) spectra of charged pions, kaons and protons in proton-proton (pp) collisions at LHC energies 0.9, 2.76 and 7TeV, we present a scaling behaviour in the pT spectra of strange particles (KS0, Λ, Ξ and φ) at these three energies. This scaling behaviour is exhibited when the spectra are expressed in a suitable scaling variable z=pT/K, where the scaling parameter K is determined by the quality factor method and increases with the center of mass energy (√{s}). The rates at which K increases with ln √{s} for these strange particles are found to be identical within errors. In the framework of the colour string percolation model, we argue that these strange particles are produced through the decay of clusters that are formed by the colour strings overlapping. We observe that the strange mesons and baryons are produced from clusters with different size distributions, while the strange mesons (baryons) KS0 and φ ( Λ and Ξ) originate from clusters with the same size distributions. The cluster's size distributions for strange mesons are more dispersed than those for strange baryons. The scaling behaviour of the pT spectra for these strange particles can be explained by the colour string percolation model in a quantitative way.

  1. Strange and non-strange baryon and antibaryon production in sulphur-tungsten and sulphur-sulphur interactions at 200 A Gev/c

    Energy Technology Data Exchange (ETDEWEB)

    Holme, A.K.

    1995-11-01

    The author has studied production of strange and multistrange baryons and antibaryons in central sulphur-tungsten, sulphur-sulphur, and lead-lead interactions at relativistic energies. The spectra of strange baryons and antibaryons provide information about the dynamics of hadronic matter under the extreme conditions realised in these collisions. The particle ratios allow the degree and the nature of the flavour equilibrium to be studied, while the transverse mass distributions provide independent information of the temperatures achieved. 143 refs.

  2. Strange and non-strange baryon and antibaryon production in sulphur-tungsten and sulphur-sulphur interactions at 200 A Gev/c

    International Nuclear Information System (INIS)

    Holme, A.K.

    1995-11-01

    The author has studied production of strange and multistrange baryons and antibaryons in central sulphur-tungsten, sulphur-sulphur, and lead-lead interactions at relativistic energies. The spectra of strange baryons and antibaryons provide information about the dynamics of hadronic matter under the extreme conditions realised in these collisions. The particle ratios allow the degree and the nature of the flavour equilibrium to be studied, while the transverse mass distributions provide independent information of the temperatures achieved. 143 refs

  3. Study of Strange and Multistrange Particles in Ultrarelativistic Nucleus-Nucleus Collisions

    CERN Multimedia

    Vande vyvre, P; Feofilov, G; Snoeys, W; Hetland, K F; Campbell, M; Klempt, W

    2002-01-01

    % NA57\\\\ \\\\ The goal of the experiment is to study the production of strange and multi-strange particles in nucleus-nucleus collisions. This study was initiated at the OMEGA spectrometer, where three ion experiments have been performed: WA85 (S-W and p-W collisions at 200 A GeV/c), WA94 (S-S and p-S collisions at 200 A GeV/c) and WA97 (Pb-Pb, p-Pb and p-Be collisions at 160 A GeV/c).\\\\ \\\\ The experiment aims at extending the scope of WA97 by:\\\\ \\\\ - investigating the beam energy dependence of the enhancements of multi-strange particle production reported by the previous experiments, and by\\\\ \\\\\\\\ \\\\- measuring the yields of strange and multi-strange particles over an extended centrality range compared with the previous experiments.\\\\ \\\\ The apparatus consists mainly of silicon pixel detector planes.

  4. Using the Moon As A Low-Noise Seismic Detector For Strange Quark Nuggets

    Science.gov (United States)

    Banerdt, W. Bruce; Chui, Talso; Griggs, Cornelius E.; Herrin, Eugene T.; Nakamura, Yosio; Paik, Ho Jung; Penanen, Konstantin; Rosenbaum, Doris; Teplitz, Vigdor L.; Young, Joseph

    2006-01-01

    Strange quark matter made of up, down and strange quarks has been postulated by Witten [1]. Strange quark matter would be nearly charge neutral and would have density of nuclear matter (10(exp 14) gm/cu cm). Witten also suggested that nuggets of strange quark matter, or strange quark nuggets (SQNs), could have formed shortly after the Big Bang, and that they would be viable candidates for cold dark matter. As suggested by de Rujula and Glashow [2], an SQN may pass through a celestial body releasing detectable seismic energy along a straight line. The Moon, being much quieter seismically than the Earth, would be a favorable place to search for such events. We review previous searches for SQNs to illustrate the parameter space explored by using the Moon as a low-noise detector of SQNs. We also discuss possible detection schemes using a single seismometer, and using an International Lunar Seismic Network.

  5. Measurement of strange particle production in the NICA fixed-target programme

    Energy Technology Data Exchange (ETDEWEB)

    Friese, Volker [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2016-08-15

    Strange particles provide a sensitive tool to study the dense and hot matter created in relativistic nuclear collisions. Although strangeness production in such collisions has been a topic of experimental and theoretical research for many years, its understanding is far from being complete. This holds in particular for multi-strange hyperons and for lower collision energies as relevant for NICA and FAIR. Multi-strange particles, being sensitive to both the mechanism of strangeness production and the net-baryon density, are expected to shed light on the state of the created matter and to indicate possible transitions to new phases of strongly interacting matter. We thus advocate the measurement of hyperons and φ mesons in a fixed-target experiment at NICA (BM rate at N), which can be achieved by a relatively compact detector system. (orig.)

  6. Strangeness photoproduction at the BGO-OD experiment

    Energy Technology Data Exchange (ETDEWEB)

    Jude, Thomas [Physikalisches Institut, Bonn University (Germany); Collaboration: BGO-OD-Collaboration

    2016-07-01

    The BGO-OD experiment at the ELSA accelerator facility uses an energy tagged bremstrahlung photon beam to investigate the internal structure of the nucleon. The setup consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. Compared to constituent quark models (CQMs), models including psuedoscalar meson-baryon interactions have had improved success in describing baryon excitation spectra. For example, the Λ(1405) appears to be dynamically generated from meson-baryon interactions at least to some extent. Vector-meson baryon interactions have also been predicted to dynamically generate states, which may have been observed in photoproduction reactions. BGO-OD is ideal for investigating low momentum transfer processes due to the acceptance and high momentum resolution at forward angles. This enables the investigation of degrees of freedom not derived from CQMs, and in particular, strangeness photoproduction where t-channel exchange mechanisms play a dominant role. With the first major data taking periods for BGO-OD complete, an extensive programme for the investigation of associated strangeness photoproduction has begun.

  7. Neutral strangeness production with the ZEUS detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Liu Chuanlei

    2007-12-15

    The inclusive production of the neutral strange particles, {lambda}, anti {lambda} and K{sup 0}{sub S} has been studied with the ZEUS detector at HERA. The measurement provides a way to understand the fragmentation process in ep collisions and to check the universality of this process. The strangeness cross sections have been measured and compared with Monte Carlo (MC) predictions. Over the kinematic regions of interest, no {lambda} to anti {lambda} asymmetry was observed. The relative yield of {lambda} and K{sup 0}{sub S} was determined and the result was compared with MC calculations and results from other experiments. A good agreement was found except for the enhancement in the photoproduction process. Clear rapidity correlation was observed for particle pairs where either quark flavor or baryon number compensation occurs. The K{sup 0}{sub S}K{sup 0}{sub S} Bose-Einstein correlation measurement gives a result consistent with those from LEP measurements. The {lambda} polarizations were measured to be consistent with zero for HERA I data. (orig.)

  8. The hydrogen bubble chamber and the strange resonances

    International Nuclear Information System (INIS)

    Alvarez, L.W.

    1989-01-01

    Work on observing strange particle resonances, already predicted by theory, was done at Berkeley by the author Luis Alvarez starting in 1953, thanks to the development of a bubble chamber filled with liquid hydrogen, which made the discovery on new particles and their mode of production easier. The first experiment, stopping K - mesons in hydrogen lead to copious production of the strangeness equal to minus one hyperons, the lambda, and sigma minus, plus and neutral, as well as enabling the first observation of muon-catalyzed fusion reactions. In 1955, funding was obtained for a seventy-two-inch bubble chamber, by far the largest ever constructed. Later computer analysis permitted calculation of track co-ordinates in real space. A neutral cascade particle, the xi, predicted by theory, had its mass measured first on the fifteen-inch chamber. The author closes with a description of the explosion in discoveries of resonance particles in the late fifties and speculates about future discoveries. (UK)

  9. Strange hadron decays involving e+e- pairs

    International Nuclear Information System (INIS)

    Soyeur, M.

    1996-01-01

    A high resolution, large acceptance e + e - detector like HADES coupled to intense secondary kaon beams could offer a remarkable opportunity to study at GSI both the electromagnetic and electroweak decays of strange hadrons. Such data can be very consistently interpreted using effective chiral Lagrangians based on the SU(3) x SU(3) symmetry. Of particular interest are a complete set of data on the electromagnetic form factors for the ρ,ω, φ and K* Dalitz decays, which would put very strong constraints on departures from ideal SU(3) mixings, and measurements of Dalitz decays of hyperons, whose electromagnetic structure is very much unknown. Better data on the nonleptonic radiative (e + e - ) decays of kaons would be most useful to study the strangeness changing weak currents and effects related to CP violation. A major progress in the understanding of these decays came recently from their description in chiral perturbation theory, where the chiral dynamics of Goldstone bosons is coupled to the weak and electromagnetic gauge fields. Those studies could be extended to the electroweak decays of hyperons. (author)

  10. "Making strange": a role for the humanities in medical education.

    Science.gov (United States)

    Kumagai, Arno K; Wear, Delese

    2014-07-01

    Stories, film, drama, and art have been used in medical education to enhance empathy, perspective-taking, and openness to "otherness," and to stimulate reflection on self, others, and the world. Yet another, equally important function of the humanities and arts in the education of physicians is that of "making strange"-that is, portraying daily events, habits, practices, and people through literature and the arts in a way that disturbs and disrupts one's assumptions, perspectives, and ways of acting so that one sees the self, others, and the world anew. Tracing the development of this concept from Viktor Shklovsky's "enstrangement" (ostranenie) through Bertolt Brecht's "alienation effect," this essay describes the use of this technique to disrupt the "automaticity of thinking" in order to discover new ways of perceiving and being in the world.Enstrangement may be used in medical education in order to stimulate critical reflection and dialogue on assumptions, biases, and taken-for-granted societal conditions that may hinder the realization of a truly humanistic clinical practice. In addition to its ability to enhance one's critical understanding of medicine, the technique of "making strange" does something else: By disrupting fixed beliefs, this approach may allow a reexamination of patient-physician relationships in terms of human interactions and provide health care professionals an opportunity-an "open space"-to bear witness and engage with other individuals during challenging times.

  11. Overview of the electromagnetic production of strange mesons at MAMI

    Energy Technology Data Exchange (ETDEWEB)

    Achenbach, P., E-mail: patrick@kph.uni-mainz.de [Institut für Kernphysik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Gómez Rodríguez, M. [Institut für Kernphysik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Tsukada, K. [Department of Physics, Tohoku University, 980-8578 Sendai (Japan); Ayerbe Gayoso, C.; Böhm, R. [Institut für Kernphysik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Borodina, O. [Institut für Kernphysik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); GSI Helmholtz Centre for Heavy Ion Research, 64291 Darmstadt (Germany); Bosnar, D. [Department of Physics, University of Zagreb, 10002 Zagreb (Croatia); Bozkurt, V. [GSI Helmholtz Centre for Heavy Ion Research, 64291 Darmstadt (Germany); Bydžovský, P. [Nuclear Physics Institute, 25068 Řež near Prague (Czech Republic); Debenjak, L. [University of Ljubljana and Institut “Jožef Stefan”, 1000 Ljubljana (Slovenia); Distler, M.O.; Esser, A. [Institut für Kernphysik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Friščić, I. [Department of Physics, University of Zagreb, 10002 Zagreb (Croatia); Fujii, Y.; Gogami, T.; Hashimoto, O.; Hirose, S.; Kanda, H.; Kaneta, M. [Department of Physics, Tohoku University, 980-8578 Sendai (Japan); Kim, E. [GSI Helmholtz Centre for Heavy Ion Research, 64291 Darmstadt (Germany); and others

    2013-09-20

    The Mainz Microtron MAMI provides a continuous-wave unpolarized or spin-polarized electron beam with energies up to 1.6 GeV and high degrees of polarization. Electro-production of strange mesons is performed in the multi-spectrometer facility with the KAOS spectrometer for kaon detection and a high-resolution spectrometer for electron detection in plane or out of plane. Differential cross section measurements of exclusive p(e,e{sup ′}K{sup +})Λ,Σ{sup 0} reactions at low four-momentum transfers in the nucleon's third resonance region have been done, followed by a measurement of the beam helicity asymmetry for p(e{sup →},e{sup ′}K{sup +})Λ. These studies are important for the understanding of the effective coupling of photons to the hadrons and their resonances and electromagnetic form factors entering different effective Lagrangian models for photo- and electro-production of strangeness. The polarized structure function, extracted from the beam helicity asymmetry, shows an especially high sensitivity to model parameters.

  12. Neutral strange particle production in neutrino interactions at Tevatron energies

    International Nuclear Information System (INIS)

    De, K.

    1988-05-01

    This thesis reports on a study of neutral strange particle production by high energy muon-neutrinos. The neutrinos were obtained from a 800 GeV proton beam-dump at Fermilab. Neutrino events were observed using a hybrid bubble chamber detector system. The data contained deep inelastic neutrino-nucleon interactions with an average momentum transfer 2 > = 23 (GeV/c) 2 . Rates for K 0 and Λ production in neutrino and anti-neutrino charged current events are presented. The distributions of these particles in Feynman x and rapidity are also studied. Significant differences were observed in the production mechanism for the K 0 meson and the Λ baryon. The production rates of K 0 's were observed to increase with energy, whereas the rates for Λ production remained essentially constant. In Feynman x, the K 0 's were produced in the central region and the Λ's were produced backwards. The data are compared with the LUND monte carlo for string fragmentation. In the monte carlo, K 0 's are mostly produced from s/bar s/ pair production during fragmentation. The Λ's are generally produced through recombination with the diquark from the target nucleon. The data agree with this model for strange particle production. 39 refs., 24 figs., 10 tabs

  13. Hybrid stars

    Indian Academy of Sciences (India)

    Hybrid stars. AsHOK GOYAL. Department of Physics and Astrophysics, University of Delhi, Delhi 110 007, India. Abstract. Recently there have been important developments in the determination of neutron ... number and the electric charge. ... available to the system to rearrange concentration of charges for a given fraction of.

  14. Pulsating stars

    CERN Document Server

    Catelan, M?rcio

    2014-01-01

    The most recent and comprehensive book on pulsating stars which ties the observations to our present understanding of stellar pulsation and evolution theory.  Written by experienced researchers and authors in the field, this book includes the latest observational results and is valuable reading for astronomers, graduate students, nuclear physicists and high energy physicists.

  15. Variable stars

    International Nuclear Information System (INIS)

    Feast, M.W.; Wenzel, W.; Fernie, J.D.; Percy, J.R.; Smak, J.; Gascoigne, S.C.B.; Grindley, J.E.; Lovell, B.; Sawyer Hogg, H.B.; Baker, N.; Fitch, W.S.; Rosino, L.; Gursky, H.

    1976-01-01

    A critical review of variable stars is presented. A fairly complete summary of major developments and discoveries during the period 1973-1975 is given. The broad developments and new trends are outlined. Essential problems for future research are identified. (B.R.H. )

  16. Star Products and Applications

    OpenAIRE

    Iida, Mari; Yoshioka, Akira

    2010-01-01

    Star products parametrized by complex matrices are defined. Especially commutative associative star products are treated, and star exponentials with respect to these star products are considered. Jacobi's theta functions are given as infinite sums of star exponentials. As application, several concrete identities are obtained by properties of the star exponentials.

  17. Pulse duration discriminator

    International Nuclear Information System (INIS)

    Kosakovskij, L.F.

    1980-01-01

    Basic circuits of a discriminator for discrimination of pulses with the duration greater than the preset one, and of a multifunctional discriminator allowing to discriminate pulses with the duration greater (tsub(p)>tsub(s)) and lesser (tsub(p) tsub(s) and with the duration tsub(p) [ru

  18. Study of strange particle production by neutral currents induced by 1 and 12 GeV neutrinos and antineutrinos

    International Nuclear Information System (INIS)

    Francois, T.L.B.

    1977-01-01

    Strange particles production by weak neutral currents was experimentally studied. The first result is a direct confirmation that neutral currents conserve strangeness (by an upper limit on ΔS=-1 production). The two other results, production rate of strange neutral particles and ratio of strange particles production for antineutrinos and neutrinos, prove that these particles are mainly produced in the final hadronic state rather than on strange sea-quarks and give an upper limit on the rate of this type of quark in the nucleon [fr

  19. All spherically symmetric charged anisotropic solutions for compact stars

    Energy Technology Data Exchange (ETDEWEB)

    Maurya, S.K. [University of Nizwa, Department of Mathematical and Physical Sciences, College of Arts and Science, Nizwa (Oman); Gupta, Y.K. [Raj Kumar Goel Institute of Technology, Department of Mathematics, Ghaziabad, UP (India); Ray, Saibal [Government College of Engineering and Ceramic Technology, Department of Physics, Kolkata, West Bengal (India)

    2017-06-15

    In the present paper we develop an algorithm for all spherically symmetric anisotropic charged fluid distributions. Considering a new source function ν(r) we find a set of solutions which is physically well behaved and represents compact stellar models. A detailed study specifically shows that the models actually correspond to strange stars in terms of their mass and radius. In this connection we investigate several physical properties like energy conditions, stability, mass-radius ratio, electric charge content, anisotropic nature and surface redshift through graphical plots and mathematical calculations. All the features from these studies are in excellent agreement with the already available evidence in theory as well as observations. (orig.)

  20. Strange metal from Gutzwiller correlations in infinite dimensions

    Science.gov (United States)

    Ding, Wenxin; Žitko, Rok; Mai, Peizhi; Perepelitsky, Edward; Shastry, B. Sriram

    2017-08-01

    Recent progress in extremely correlated Fermi liquid theory (ECFL) and the dynamical mean field theory (DMFT) enables us to accurately compute in the d →∞ limit the resistivity of the t -J model after setting J →0 . This is also the U =∞ Hubbard model. Since J is set to zero, our study isolates the dynamical effects of the single occupation constraint enforced by the projection operator originally introduced by Gutzwiller. We study three densities n =.75 ,.8 ,.85 that correspond to a range between the overdoped and optimally doped Mott insulating state. We delineate four distinct regimes separated by three crossovers, which are characterized by different behaviors of the resistivity ρ . We find at the lowest temperature T a Gutzwiller correlated Fermi liquid regime with ρ ∝T2 extending up to an effective Fermi temperature that is dramatically suppressed from the noninteracting value by the proximity to half filling, n ˜1 . This is followed by a Gutzwiller correlated strange metal regime with ρ ∝(T -T0) , i.e., a linear resistivity extrapolating back to ρ =0 at a positive T0. At a higher temperature scale this crosses over into the bad metal regime with ρ ∝(T +T1) , i.e., a linear resistivity extrapolating back to a finite resistivity at T =0 and passing through the Ioffe-Regel-Mott value where the mean free path is a few lattice constants. This regime finally gives way to the high T metal regime, where we find ρ ∝T , i.e., a linear resistivity extrapolating back to zero at T =0 . The present work emphasizes the first two, i.e., the two lowest temperature regimes, where the availability of an analytical ECFL theory is of help in identifying the changes in related variables entering the resistivity formula that accompanies the onset of linear resistivity, and the numerically exact DMFT helps to validate the results. We also examine thermodynamical variables such as the magnetic susceptibility, compressibility, heat capacity, and entropy and

  1. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Frigaard, Peter; Brorsen, Michael

    Nærværende rapport beskriver foreløbige hovedkonklusioner på modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star i perioden 13/9 2004 til 12/11 2004.......Nærværende rapport beskriver foreløbige hovedkonklusioner på modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star i perioden 13/9 2004 til 12/11 2004....

  2. Cold dense baryonic matter and compact stars

    International Nuclear Information System (INIS)

    Hyun Kyu Lee; Sang-Jin Sin; Mannque Rho

    2011-01-01

    Probing dense hadronic matter is thus far an uncharted field of physics. Here we give a brief summary of the highlights of what has been so far accomplished and what will be done in the years ahead by the World Class University III Project at Hanyang University in the endeavor to unravel and elucidate the multi-facet of the cold dense baryonic matter existing in the interior of the densest visible stable object in the universe, i.e. neutron stars, strangeness stars and/or quark stars, from a modest and simplified starting point of an effective field theory modeled on the premise of QCD as well as from a gravity dual approach of hQCD. The core of the matter of our research is the possible origin of the ∼ 99% of the proton mass that is to be accounted for and how the 'vacuum' can be tweaked so that the source of the mass generation can be uncovered by measurements made in terrestrial as well as space laboratories. Some of the issues treated in the program concern what can be done - both theoretically and experimentally - in anticipation of what's to come for basic physics research in Korea. (authors)

  3. Constituent quarks and enhancement of multi-strange baryons in heavy-ion collisions

    International Nuclear Information System (INIS)

    Behera, Nirbhay Kumar; Nandi, Basanta Kumar; Sahoo, Raghunath

    2011-01-01

    Heavy-ion collisions at relativistic energies aim to produce a state of matter which is governed by partonic degrees of freedom, known as Quark-Gluon Plasma (QGP). In the central rapidity region, strangeness enhancement has been proposed as a potential signature of QGP. It has been observed that a quark participant scaling of the multi-strange baryon production and also a strangeness scaling of the enhancement. This confirms that the partonic degrees of freedom is playing a major role in the particle production mechanism and may therefore significantly determine the formation of QGP in heavy ion collisions

  4. Low-lying 1/2-hidden strange pentaquark states in the constituent quark model

    Institute of Scientific and Technical Information of China (English)

    Hui Li; Zong-Xiu Wu; Chun-Sheng An; Hong Chen

    2017-01-01

    We investigate the spectrum of the low-lying 1/2-hidden strange pentaquark states,employing the constituent quark model,and looking at two ways within that model of mediating the hyperfine interaction between quarks-Goldstone boson exchange and one gluon exchange.Numerical results show that the lowest 1/2-hidden strange pentaquark state in the Goldstone boson exchange model lies at ~ 1570 MeV,so this pentaquark configuration may form a notable component in S11(1535) if the Goldstone boson exchange model is applied.This is consistent with the prediction that S11 (1535) couples very strongly to strangeness channels.

  5. Influence of rescattering on the strange particle spectrum

    International Nuclear Information System (INIS)

    David, C.; Hartnack, C; Aichelin, J.

    1997-01-01

    Applying a new method of rescattering which is based on the neural network technique we study the influence of rescattering on the spectra of strange particles produced in heavy ion reactions. In contradistinction to formal approaches the rescattering is done explicitly and not in a perturbative fashion. We present a comparison of our calculations for the system Ni (1.93 A.GeV) + Ni with recent data of the FOPI collaboration. We find that even for this small system rescattering changes the observables considerably but does not invalidate the role of the kaons as a messenger from the high density zone. We cannot confirm the conjecture that the kaon flow can be of use for the determination of the optical potential of the kaon. The experimental results agree with the computations showing a minimal change of the K + particles in the nuclear matter. Probably, the situation is very different for the K - particles

  6. |Vus| determination from inclusive strange tau decay and lattice HVP

    Directory of Open Access Journals (Sweden)

    Boyle Peter

    2018-01-01

    Full Text Available We propose and apply a novel approach to determining |Vus| which uses inclusive strange hadronic tau decay data and hadronic vacuum polarization functions (HVPs computed on the lattice. The experimental and lattice data are related through dispersion relations which employ a class of weight functions having poles at space-like momentum. Implementing this approach using lattice data generated by the RBC/UKQCD collaboration, we show examples of weight functions which strongly suppress spectral integral contributions from the region where experimental data either have large uncertainties or do not exist while at the same time allowing accurate determinations of relevant lattice HVPs. Our result for |Vus| is in good agreement with determinations from K physics and 3-family CKM unitarity. The advantages of the new approach over the conventional sum rule analysis will be discussed.

  7. |Vus| determination from inclusive strange tau decay and lattice HVP

    Science.gov (United States)

    Boyle, Peter; Hudspith, Renwick James; Izubuchi, Taku; Jüttner, Andreas; Lehner, Christoph; Lewis, Randy; Maltman, Kim; Ohki, Hiroshi; Portelli, Antonin; Spraggs, Matthew

    2018-03-01

    We propose and apply a novel approach to determining |Vus| which uses inclusive strange hadronic tau decay data and hadronic vacuum polarization functions (HVPs) computed on the lattice. The experimental and lattice data are related through dispersion relations which employ a class of weight functions having poles at space-like momentum. Implementing this approach using lattice data generated by the RBC/UKQCD collaboration, we show examples of weight functions which strongly suppress spectral integral contributions from the region where experimental data either have large uncertainties or do not exist while at the same time allowing accurate determinations of relevant lattice HVPs. Our result for |Vus| is in good agreement with determinations from K physics and 3-family CKM unitarity. The advantages of the new approach over the conventional sum rule analysis will be discussed.

  8. Strange b baryon production and lifetime in Z decays

    CERN Document Server

    Buskulic, Damir; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Nief, J Y; Odier, P; Pietrzyk, B; Casado, M P; Chmeissani, M; Crespo, J M; Delfino, M C; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Orteu, S; Padilla, C; Park, I C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Alemany, R; Bazarko, A O; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Lutters, G; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Mir, L M; Moneta, L; Oest, T; Pacheco, A; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schmitt, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wagner, A; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Rossignol, J M; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Casper, David William; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Abbaneo, D; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Moutoussi, A; Nash, J; Sedgbeer, J K; Stacey, A M; Williams, M D; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Williams, M I; Galla, A; Giehl, I; Greene, A M; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Konstantinidis, N P; Payre, P; Rousseau, D; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Aleppo, M; Ragusa, F; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Choi, Y; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Höcker, A; Jacholkowska, A; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Park, H J; Schune, M H; Simion, S; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Verdini, P G; Walsh, J; Blair, G A; Bryant, L M; Cerutti, F; Chambers, J T; Gao, Y; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Maley, P; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Boswell, R; Brew, C A J; Cartwright, S L; Combley, F; Köksal, A; Lehto, M H; Newton, W M; Reeve, J; Thompson, L F; Böhrer, A; Brandt, S; Büscher, V; Cowan, G D; Grupen, Claus; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Greening, T C; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    In a data sample of approximately four million hadronic Z decays recorded with the ALEPH detector from 1990 to 1995, a search for the strange b baryon Xi_b is performed with a study of Xi-lepton correlations. Forty-four events with same sign Xi- l- combinations are found whereas 8.4 are expected based on on the rate of opposite sign Xi- l+ combinations. This significant excess is interpreted as evidence for Xi_b semileptonic decays. The measured product branching ratio is: Br( b -> Xi_b) Br( Xi_b -> Xc X l- nu) Br( Xc -> Xi- X') = (5.4 +/- 1.1(stat) +/- 0.8(syst) ) 10**-4 per lepton species, averaged over electrons and muons, with Xc a charmed baryo\\ n. The Xi_b lifetime is measured to be : tau = 1.35 (+0.37 -0.28 (stat)) (+0.15 -0.17 (syst)) ps.

  9. Production of strange baryons and antibaryons in relativistic ion collisions

    CERN Multimedia

    2002-01-01

    A new state of matter - the quark-gluon plasma - may be produced in $^{32}$S interactions with heavy nuclei A (Ag, Cu, Pb and S targets) at beam momenta up to 200 GeV/c per nucleon. A possible signature of this state is a strongly enhanced yield of strange quark pairs. The aim of the experiment is therefore a measurement of differential cross sections for production of neutral kaons, $\\Lambda, \\Xi, \\Omega$ and their antiparticles with high statistics. Furthermore charged particle trajectories will be reconstructed and the total energy flow and its fluctuations will be determined in the forward c.m.s. hemisphere. \\\\\\\\The experiment is performed with a modified EHS configuration; its characteristic features are:\\\\\\\\ - Tracking chambers.\\\\ - A Cerenkov counter.\\\\ - A TPC for 3-dimensional unambiguous space point tracking.\\\\ - A magnet to sweep most of the produced particles from the tracking devices.\\\\ - Hadronic and electromagnetic calorimeters covering hermetically the forward c.m.s. hemisphere.\\\\ - ...

  10. Extreme neutron stars from Extended Theories of Gravity

    Energy Technology Data Exchange (ETDEWEB)

    Astashenok, Artyom V. [I. Kant Baltic Federal University, Institute of Physics and Technology, Nevskogo st. 14, Kaliningrad, 236041 (Russian Federation); Capozziello, Salvatore [Dipartimento di Fisica, Università di Napoli ' ' Federico II' ' , Via Cinthia, 9, Napoli, I-80126 Italy (Italy); Odintsov, Sergei D., E-mail: artyom.art@gmail.com, E-mail: capozziello@na.infn.it, E-mail: odintsov@ieec.uab.es [Instituciò Catalana de Recerca i Estudis Avançats (ICREA), Barcelona (Spain)

    2015-01-01

    We discuss neutron stars with strong magnetic mean fields in the framework of Extended Theories of Gravity. In particular, we take into account models derived from f(R) and f(G) extensions of General Relativity where functions of the Ricci curvature invariant R and the Gauss-Bonnet invariant G are respectively considered. Dense matter in magnetic mean field, generated by magnetic properties of particles, is described by assuming a model with three meson fields and baryons octet. As result, the considerable increasing of maximal mass of neutron stars can be achieved by cubic corrections in f(R) gravity. In principle, massive stars with M > 4M{sub ☉} can be obtained. On the other hand, stable stars with high strangeness fraction (with central densities ρ{sub c} ∼ 1.5–2.0 GeV/fm{sup 3}) are possible considering quadratic corrections of f(G) gravity. The magnetic field strength in the star center is of order 6–8 × 10{sup 18} G. In general, we can say that other branches of massive neutron stars are possible considering the extra pressure contributions coming from gravity extensions. Such a feature can constitute both a probe for alternative theories and a way out to address anomalous self-gravitating compact systems.

  11. Magnetotransport in a Model of a Disordered Strange Metal

    Science.gov (United States)

    Patel, Aavishkar A.; McGreevy, John; Arovas, Daniel P.; Sachdev, Subir

    2018-04-01

    Despite much theoretical effort, there is no complete theory of the "strange" metal state of the high temperature superconductors, and its linear-in-temperature T resistivity. Recent experiments showing an unexpected linear-in-field B magnetoresistivity have deepened the puzzle. We propose a simple model of itinerant electrons, interacting via random couplings, with electrons localized on a lattice of "quantum dots" or "islands." This model is solvable in a particular large-N limit and can reproduce observed behavior. The key feature of our model is that the electrons in each quantum dot are described by a Sachdev-Ye-Kitaev model describing electrons without quasiparticle excitations. For a particular choice of the interaction between the itinerant and localized electrons, this model realizes a controlled description of a diffusive marginal-Fermi liquid (MFL) without momentum conservation, which has a linear-in-T resistivity and a T ln T specific heat as T →0 . By tuning the strength of this interaction relative to the bandwidth of the itinerant electrons, we can additionally obtain a finite-T crossover to a fully incoherent regime that also has a linear-in-T resistivity. We describe the magnetotransport properties of this model and show that the MFL regime has conductivities that scale as a function of B /T ; however, the magnetoresistance saturates at large B . We then consider a macroscopically disordered sample with domains of such MFLs with varying densities of electrons and islands. Using an effective-medium approximation, we obtain a macroscopic electrical resistance that scales linearly in the magnetic field B applied perpendicular to the plane of the sample, at large B . The resistance also scales linearly in T at small B , and as T f (B /T ) at intermediate B . We consider implications for recent experiments reporting linear transverse magnetoresistance in the strange metal phases of the pnictides and cuprates.

  12. Neutron stars interiors: Theory and reality

    International Nuclear Information System (INIS)

    Stone, J.R.

    2016-01-01

    There are many fascinating processes in the universe which we observe in more detail thanks to increasingly sophisticated technology. One of the most interesting phenomena is the life cycle of stars, their birth, evolution and death. If the stars are massive enough, they end their lives in a core-collapse supernova explosion, one of the most violent events in the universe. As a result, the densest objects in the universe, neutron stars and/or black holes, are created. The physical basis of these events should be understood in line with observation. Unfortunately, available data do not provide adequate constraints for many theoretical models of dense matter. One of the most open areas of research is the composition of matter in the cores of neutron stars. Unambiguous fingerprints for the appearance and evolution of particular components, such as strange baryons and mesons, with increasing density, have not been identified. In particular, the hadron-quark phase transition remains a subject of intensive research. In this contribution we briefly survey the most promising observational and theoretical directions leading to progress in understanding high density matter in neutron stars. A possible way forward in modeling high-density matter is outlined, exemplified by the quark-meson-coupling model (QMC). This model makes connection between hadronic structure and the underlying quark make-up. It offers a natural explanation for the saturation of nuclear force and treats high-density matter, containing the full baryon octet, in terms of four uniquely defined parameters adjusted to properties of symmetric nuclear matter at saturation. (orig.)

  13. Neutron stars interiors: Theory and reality

    Science.gov (United States)

    Stone, J. R.

    2016-03-01

    There are many fascinating processes in the universe which we observe in more detail thanks to increasingly sophisticated technology. One of the most interesting phenomena is the life cycle of stars, their birth, evolution and death. If the stars are massive enough, they end their lives in a core-collapse supernova explosion, one of the most violent events in the universe. As a result, the densest objects in the universe, neutron stars and/or black holes, are created. The physical basis of these events should be understood in line with observation. Unfortunately, available data do not provide adequate constraints for many theoretical models of dense matter. One of the most open areas of research is the composition of matter in the cores of neutron stars. Unambiguous fingerprints for the appearance and evolution of particular components, such as strange baryons and mesons, with increasing density, have not been identified. In particular, the hadron-quark phase transition remains a subject of intensive research. In this contribution we briefly survey the most promising observational and theoretical directions leading to progress in understanding high density matter in neutron stars. A possible way forward in modeling high-density matter is outlined, exemplified by the quark-meson-coupling model (QMC). This model makes connection between hadronic structure and the underlying quark make-up. It offers a natural explanation for the saturation of nuclear force and treats high-density matter, containing the full baryon octet, in terms of four uniquely defined parameters adjusted to properties of symmetric nuclear matter at saturation.

  14. Neutron stars interiors: Theory and reality

    Energy Technology Data Exchange (ETDEWEB)

    Stone, J.R. [University of Oxford, Department of Physics, Oxford (United Kingdom); University of Tennessee, Department of Physics and Astronomy, Knoxville, TN (United States)

    2016-03-15

    There are many fascinating processes in the universe which we observe in more detail thanks to increasingly sophisticated technology. One of the most interesting phenomena is the life cycle of stars, their birth, evolution and death. If the stars are massive enough, they end their lives in a core-collapse supernova explosion, one of the most violent events in the universe. As a result, the densest objects in the universe, neutron stars and/or black holes, are created. The physical basis of these events should be understood in line with observation. Unfortunately, available data do not provide adequate constraints for many theoretical models of dense matter. One of the most open areas of research is the composition of matter in the cores of neutron stars. Unambiguous fingerprints for the appearance and evolution of particular components, such as strange baryons and mesons, with increasing density, have not been identified. In particular, the hadron-quark phase transition remains a subject of intensive research. In this contribution we briefly survey the most promising observational and theoretical directions leading to progress in understanding high density matter in neutron stars. A possible way forward in modeling high-density matter is outlined, exemplified by the quark-meson-coupling model (QMC). This model makes connection between hadronic structure and the underlying quark make-up. It offers a natural explanation for the saturation of nuclear force and treats high-density matter, containing the full baryon octet, in terms of four uniquely defined parameters adjusted to properties of symmetric nuclear matter at saturation. (orig.)

  15. Appliance Efficiency Standards and Price Discrimination

    Energy Technology Data Exchange (ETDEWEB)

    Spurlock, Cecily Anna [Univ. of California, Berkeley, CA (United States)

    2013-05-08

    I explore the effects of two simultaneous changes in minimum energy efficiency and ENERGY STAR standards for clothes washers. Adapting the Mussa and Rosen (1978) and Ronnen (1991) second-degree price discrimination model, I demonstrate that clothes washer prices and menus adjusted to the new standards in patterns consistent with a market in which firms had been price discriminating. In particular, I show evidence of discontinuous price drops at the time the standards were imposed, driven largely by mid-low efficiency segments of the market. The price discrimination model predicts this result. On the other hand, in a perfectly competition market, prices should increase for these market segments. Additionally, new models proliferated in the highest efficiency market segment following the standard changes. Finally, I show that firms appeared to use different adaptation strategies at the two instances of the standards changing.

  16. Strange Meson Radiative Capture on the Proton in Low Energy QCD Lagrangian

    Institute of Scientific and Technical Information of China (English)

    ZHOU Li-Juan; MA Wei-Xing

    2002-01-01

    Based on our low energy QCD Lagrangian description of strange meson photoproduction off the protonand the crossing symmetry, the strange meson radiative capture on the proton, K- + p →γ + A, is investigated in the[SUsF (6) O(3)]sym. SUc (3) quark model of baryon structure with the same input parameter, the only strong couplingconstant aM, as that in the strange meson photoproduction off the proton γ + p → K+ + A, a crossing channel of thecapture reaction. A good agreement on the branching ratio between the predictions and data is obtained successfully.This excellent fit indicates that our low energy QCD Lagrangian theory with only one free parameter is an advancedand unified description of strange meson photoproduction and its associated radiative capture.

  17. Strange Meson Radiative Capture on the Proton in Low Energy QCD Lagrangian

    Institute of Scientific and Technical Information of China (English)

    ZHOULi-Juan; MAWei-Xing; 等

    2002-01-01

    Based on our low energy QCD Lagrangian description of strange meson photoproduction off the proton and the crossing symmetry,the strange meson radiative capture on the proton,K-+p→γ+A,is investigated in the [SU SF(6)×O(3)]sym,SUc(3) quark model of baryon structure with the same input parameter,the only strong coupling constant αM,as that in the strange meson photoproduction off the proton γ+p-→K+ Α,a crossing channel of the capture reaction,A good agreement on the branching ratio between the predictions and data is obtained successfully.This excellent fit indicates that our low energy QCD Lagrangian theory with only one free parameter is an advanced and unified description of strange meson photoproduction and its associated radiative capture.

  18. Neutral strange particle production in neutrino and antineutrino charged current interactions on protons

    Science.gov (United States)

    Jones, G. T.; Jones, R. W. L.; Kennedy, B. W.; O'Neale, S. W.; Villalobos-Baillie, O.; Klein, H.; Morrison, D. R. O.; Schmid, P.; Wachsmuth, H.; Miller, D. B.; Mobayyen, M. M.; Wainstein, S.; Aderholz, M.; Hantke, D.; Katz, U. F.; Kern, J.; Schmitz, N.; Wittek, W.; Borner, H. P.; Myatt, G.; Radojicic, D.; Bullock, F. W.; Burke, S.

    1993-06-01

    The production of the neutral strange particles K 0, Λ andbar Λ in vp andbar vp charged current interactions is studied in an experiment with the Big European Bubble Chamber. Mean multiplicities are measured as a function of the event variables E v, W 2 and Q 2 and of the hadron variables x F, z and p {T/2}. K *± (892) and ∑ *± (1385) signals are observed, whereas there is no evidence for ∑ *- (1385) production in vp scattering. Forward, backward and total mean multiplicities are found to compare well with the predictions of an empirical model for deep-inelastic reactions in the case of the strange mesons K 0 and K *± (892) but less so for the strange baryons Λ,bar Λ and ∑ *± (1385). The strange baryon multiplicities are used to obtain the decuplet to octet baryon production ratio and to assess the probabilities of a uu or ud system to break up.

  19. Handling conditional discrimination

    NARCIS (Netherlands)

    Zliobaite, I.; Kamiran, F.; Calders, T.G.K.

    2011-01-01

    Historical data used for supervised learning may contain discrimination. We study how to train classifiers on such data, so that they are discrimination free with respect to a given sensitive attribute, e.g., gender. Existing techniques that deal with this problem aim at removing all discrimination

  20. The Badness of Discrimination

    DEFF Research Database (Denmark)

    Lippert-Rasmussen, Kasper

    2006-01-01

    . In this paper I address these issues. First, I offer a taxonomy of discrimination. I then argue that discrimination is bad, when it is, because it harms people. Finally, I criticize a rival, disrespect-based account according to which discrimination is bad regardless of whether it causes harm....

  1. Strangeness and charm production in nucleus-nucleus collisions at beam energies near the thresholds

    International Nuclear Information System (INIS)

    Senger, P.

    2001-01-01

    The creation of strangeness and charm in nucleus-nucleus collisions at threshold beam energies is discussed as a probe for compressed baryonic matter. Experimental data on strangeness production at SIS energies indicate that the properties of kaons and antikaons are modified in the dense nuclear medium. An experiment is proposed to explore the QCD phase diagram in the region of highest baryon densities. An important observable will be charm production close to threshold. (orig.)

  2. The STAR endcap electromagnetic calorimeter

    International Nuclear Information System (INIS)

    Allgower, C.E.; Anderson, B.D.; Baldwin, A.R.; Balewski, J.; Belt-Tonjes, M.; Bland, L.C.; Brown, R.L.; Cadman, R.V.; Christie, W.; Cyliax, I.; Dunin, V.; Efimov, L.; Eppley, G.; Gagliardi, C.A.; Gagunashvili, N.; Hallman, T.; Hunt, W.; Jacobs, W.W.; Klyachko, A.; Krueger, K.; Kulikov, A.; Ogawa, A.; Panebratsev, Y.; Planinic, M.; Puskar-Pasewicz, J.; Rakness, G.; Razin, S.; Rogachevski, O.; Shimansky, S.; Solberg, K.A.; Sowinski, J.; Spinka, H.; Stephenson, E.J.; Tikhomirov, V.; Tokarev, M.; Tribble, R.E.; Underwood, D.; Vander Molen, A.M.; Vigdor, S.E.; Watson, J.W.; Westfall, G.; Wissink, S.W.; Yokosawa, A.; Yurevich, V.; Zhang, W.-M.; Zubarev, A.

    2003-01-01

    The STAR endcap electromagnetic calorimeter will provide full azimuthal coverage for high-p T photons, electrons and electromagnetically decaying mesons over the pseudorapidity range 1.086≤η≤2.00. It includes a scintillating-strip shower-maximum detector to provide π 0 /γ discrimination and preshower and postshower layers to aid in distinguishing between electrons and charged hadrons. The triggering capabilities and coverage it offers are crucial for much of the spin physics program to be carried out in polarized proton-proton collisions

  3. The STAR endcap electromagnetic calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Allgower, C.E.; Anderson, B.D.; Baldwin, A.R.; Balewski, J.; Belt-Tonjes, M.; Bland, L.C.; Brown, R.L.; Cadman, R.V.; Christie, W.; Cyliax, I.; Dunin, V.; Efimov, L.; Eppley, G.; Gagliardi, C.A.; Gagunashvili, N.; Hallman, T.; Hunt, W.; Jacobs, W.W.; Klyachko, A.; Krueger, K.; Kulikov, A.; Ogawa, A.; Panebratsev, Y.; Planinic, M.; Puskar-Pasewicz, J.; Rakness, G.; Razin, S.; Rogachevski, O.; Shimansky, S.; Solberg, K.A.; Sowinski, J.; Spinka, H.; Stephenson, E.J.; Tikhomirov, V.; Tokarev, M.; Tribble, R.E.; Underwood, D.; Vander Molen, A.M.; Vigdor, S.E. E-mail: vigdor@iucf.indiana.edu; Watson, J.W.; Westfall, G.; Wissink, S.W.; Yokosawa, A.; Yurevich, V.; Zhang, W.-M.; Zubarev, A

    2003-03-01

    The STAR endcap electromagnetic calorimeter will provide full azimuthal coverage for high-p{sub T} photons, electrons and electromagnetically decaying mesons over the pseudorapidity range 1.086{<=}{eta}{<=}2.00. It includes a scintillating-strip shower-maximum detector to provide {pi}{sup 0}/{gamma} discrimination and preshower and postshower layers to aid in distinguishing between electrons and charged hadrons. The triggering capabilities and coverage it offers are crucial for much of the spin physics program to be carried out in polarized proton-proton collisions.

  4. Determination of strange sea distributions from {nu}N deep inelastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Alekhin, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)]|[Inst. for High Energy Physics, Protvino (Russian Federation); Kulagin, S. [Academy of Sciences of Russia, Moscow (Russian Federation). Inst. for Nuclear Research; Petti, R. [South Carolina Univ., Columbia, SC (United States). Dept. of Physics and Astronomy

    2008-12-15

    We present an analysis of the nucleon strange sea extracted from a global Parton Distribution Function fit including the neutrino and anti-neutrino dimuon data by the CCFR and NuTeV collaborations, the inclusive charged lepton-nucleon Deep Inelastic Scattering and Drell-Yan data. The (anti-)neutrino induced dimuon analysis is constrained by the semi-leptonic charmed-hadron branching ratio B{sub {mu}}=(8.8{+-}0.5)%, determined from the inclusive charmed hadron measurements performed by the FNAL-E531 and CHORUS neutrino emulsion experiments. Our analysis yields a strange sea suppression factor {kappa}(Q{sup 2}=20 GeV{sup 2})=0.62{+-}0.04, the most precise value available, an x-distribution of total strange sea that is slightly softer than the non-strange sea, and an asymmetry between strange and anti-strange quark distributions consistent with zero (integrated over x it is equal to 0.0013{+-}0.0009 at Q{sup 2}=20 GeV{sup 2}). (orig.)

  5. Strange Quark Magnetic Moment of the Nucleon at the Physical Point.

    Science.gov (United States)

    Sufian, Raza Sabbir; Yang, Yi-Bo; Alexandru, Andrei; Draper, Terrence; Liang, Jian; Liu, Keh-Fei

    2017-01-27

    We report a lattice QCD calculation of the strange quark contribution to the nucleon's magnetic moment and charge radius. This analysis presents the first direct determination of strange electromagnetic form factors including at the physical pion mass. We perform a model-independent extraction of the strange magnetic moment and the strange charge radius from the electromagnetic form factors in the momentum transfer range of 0.051  GeV^{2}≲Q^{2}≲1.31  GeV^{2}. The finite lattice spacing and finite volume corrections are included in a global fit with 24 valence quark masses on four lattices with different lattice spacings, different volumes, and four sea quark masses including one at the physical pion mass. We obtain the strange magnetic moment G_{M}^{s}(0)=-0.064(14)(09)μ_{N}. The four-sigma precision in statistics is achieved partly due to low-mode averaging of the quark loop and low-mode substitution to improve the statistics of the nucleon propagator. We also obtain the strange charge radius ⟨r_{s}^{2}⟩_{E}=-0.0043(16)(14)  fm^{2}.

  6. Life of a star

    International Nuclear Information System (INIS)

    Henbest, Nigel.

    1988-01-01

    The paper concerns the theory of stellar evolution. A description is given of:- how a star is born, main sequence stars, red giants, white dwarfs, supernovae, neutron stars and black holes. A brief explanation is given of how the death of a star as a supernova can trigger off the birth of a new generation of stars. Classification of stars and the fate of our sun, are also described. (U.K.)

  7. Pulse-width discriminators

    International Nuclear Information System (INIS)

    Budyashov, Yu.G.; Grebenyuk, V.M.; Zinov, V.G.

    1978-01-01

    A pulse duration discriminator is described which is intended for processing signals from multilayer scintillators. The basic elements of the scintillator are: an input gate, a current generator, an integrating capacitor, a Schmidt trigger and an anticoincidence circuit. The basic circuit of the discriminator and its time diagrams explaining its operating are given. The discriminator is based on microcircuits. Pulse duration discrimination threshold changes continuously from 20 to 100 ns, while its amplitude threshold changes within 20 to 100 mV. The temperature instability of discrimination thresholds (both in pulse width and in amplitude) is better than 0.1 per cent/deg C

  8. Spontaneous scalarization with an extremely massive field and heavy neutron stars

    Science.gov (United States)

    Morisaki, Soichiro; Suyama, Teruaki

    2017-10-01

    We investigate the internal structure and the mass-radius relation of neutron stars in a recently proposed scalar-tensor theory dubbed asymmetron in which a massive scalar field undergoes spontaneous scalarization inside neutron stars. We focus on the case where the Compton wavelength is shorter than 10 km, which has not been investigated in the literature. By solving the modified Einstein equations, either purely numerically or by partially using a semianalytic method, we find that not only the weakening of gravity by spontaneous scalarization but also the scalar force affect the internal structure significantly in the massive case. We also find that the maximum mass of neutron stars is larger for certain parameter sets than that in general relativity and reaches 2 M⊙ even if the effect of strange hadrons is taken into account. There is even a range of parameters where the maximum mass of neutron stars largely exceeds the threshold that violates the causality bound in general relativity.

  9. Near-side azimuthal and pseudorapidity correlations using neutral strange baryons and mesons in d +Au , Cu + Cu, and Au + Au collisions at √{sN N}=200 GeV

    Science.gov (United States)

    Abelev, B.; Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Barnby, L. S.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bombara, M.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chatterjee, A.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Gaillard, L.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Hamad, A. I.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, T.; Huang, B.; Huang, X.; Huang, H. Z.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jentsch, A.; Jia, J.; Jiang, K.; Jones, P. G.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Koetke, D. D.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kumar, L.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, C.; Li, Y.; Li, W.; Li, X.; Li, X.; Lin, T.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, S.; Luo, X.; Ma, L.; Ma, R.; Ma, G. L.; Ma, Y. G.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Matis, H. S.; McDonald, D.; McKinzie, S.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nattrass, C.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Sharma, A.; Sharma, M. K.; Shen, W. Q.; Shi, Z.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, Z.; Sun, X. M.; Surrow, B.; Svirida, D. N.; Tang, Z.; Tang, A. H.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, H.; Wang, Y.; Wang, G.; Wang, Y.; Wang, J. S.; Wang, F.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xin, K.; Xu, Y. F.; Xu, Q. H.; Xu, N.; Xu, J.; Xu, H.; Xu, Z.; Yang, Y.; Yang, Q.; Yang, S.; Yang, Y.; Yang, Y.; Yang, C.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, S.; Zhang, X. P.; Zhang, Y.; Zhang, S.; Zhang, J. B.; Zhang, J.; Zhang, J.; Zhang, Z.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

    2016-07-01

    We present measurements of the near side of triggered di-hadron correlations using neutral strange baryons (Λ ,Λ ¯) and mesons (KS0) at intermediate transverse momentum (3 < pT <6 GeV /c ) to look for possible flavor and baryon-meson dependence. This study is performed in d +Au , Cu+Cu, and Au+Au collisions at √{sN N}=200 GeV measured by the STAR experiment at RHIC. The near-side di-hadron correlation contains two structures, a peak which is narrow in azimuth and pseudorapidity consistent with correlations from jet fragmentation, and a correlation in azimuth which is broad in pseudorapidity. The particle composition of the jet-like correlation is determined using identified associated particles. The dependence of the conditional yield of the jet-like correlation on the trigger particle momentum, associated particle momentum, and centrality for correlations with unidentified trigger particles are presented. The neutral strange particle composition in jet-like correlations with unidentified charged particle triggers is not well described by PYTHIA. However, the yield of unidentified particles in jet-like correlations with neutral strange particle triggers is described reasonably well by the same model.

  10. LABOR DISCRIMINATION IN BULGARIA

    Directory of Open Access Journals (Sweden)

    Vyara Slavyanska

    2017-03-01

    Full Text Available Labor discrimination is a phenomenon with very serious social and economic consequences, which has increased actuality and importance in Bulgaria nowadays. Because of the high price of discrimination, building effective anti-discrimination legislation occupies a special place in the policy of the European Union. Despite the European directives, the presence of anti-discrimination legislation and the broadly declared anti-discrimination inclinations in our country, these are absolutely not enough for providing environment of equality, with a climate of respect and tolerance to the differences. It turns out that certain groups are definitely victims of labor discrimination. In this connection the present article consecutively identifies these groups, as well as the reasons for their discrimination, underlining the necessity and benefits of the integration of the different.

  11. The effect of the scalar-isovector meson field on hyperon-rich neutron star matter

    International Nuclear Information System (INIS)

    Mi, Aijun; Zuo, Wei; Li, Ang

    2008-01-01

    We investigate the effect of the scalar-isovector δ-meson field on the equation of state (EOS) and composition of hyperonic neutron star matter, and the properties of hyperonic neutron stars within the framework of the relativistic mean field theory. The influence of the δ-field turns out to be quite different and generally weaker for hyperonic neutron star matter as compared to that for npeμ neutron star matter. We find that inclusion of the δ-field enhances the strangeness content slightly and consequently moderately softens the EOS of neutron star matter in its hyperonic phase. As for the composition of hyperonic star matter, the effect of the δ-field is shown to shift the onset of the negatively-charged (positively-charged) hyperons to slightly lower (higher) densities and to enhance (reduce) their abundances. The influence of the δ-field on the maximum mass of hyperonic neutron stars is found to be fairly weak, whereas inclusion of the δ-field turns out to enhance sizably both the radii and the moments of inertia of neutron stars with given masses. It is also shown that the effects of the δ-field on the properties of hyperonic neutron stars remain similar in the case of switching off the Σ hyperons. (author)

  12. PREFACE: SQM2007 International Conference on Strangeness in Quark Matter

    Science.gov (United States)

    Šafařík, Karel; Šándor, Ladislav; Tomášik, Boris

    2008-04-01

    The International Conference on `Strangeness in Quark Matter' (SQM) was held from 24-29 June 2007 at the Congress Hall of the city cultural centre in the charming mediaeval town of Levoča in north-eastern Slovakia. The Institute of Experimental Physics of the Slovak Academy of Science and the Faculty of Science of the P J Šafárik University in Košice shared the duties of main organizers of the conference. SQM2007 was attended by more than 100 participants from about 20 countries. The natural beauty and the rich cultural and historical monuments of the surrounding Spiš (Scepusium) region created an inspiring setting for the scientific, social and cultural framework of the conference. Continuing the trend started at the SQM2006 conference, heavy flavour physics in heavy-ion collisions was a topic given equal importance in the SQM2007 programme alongside strange quark physics. The Symposium for Students, from Students, organized by Christian Klein-Boesing and Boris Tomášik on the basis of the contributed abstracts, was again an integral and successful part of the conference. The jury, drawn from the organizers, awarded William A Horowitz (Columbia University) the title of best student contribution. The good news is that many students and younger researchers attended the conference. This could not have happened without generous support from our sponsors whom we would like to thank for valuable financial support: CERN, Journal of Physics G, the Prešov self-governing region authorities and the Slovak Physical Society. The kind assistance of the mayor of the town of Levoča is also warmly acknowledged. We would like to extend our gratitude to our colleagues and students from the organizing institutions for their diligent work prior to and during the conference, which ensured that everything worked smoothly. Our special thanks go to our secretaries, Adri Chomičová and Mery Šemš'aková, as well as to the management of the SATEL Hotel in Levoča for their highly

  13. Low-lying charmed and charmed-strange baryon states

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Bing [Anyang Normal University, Department of Physics, Anyang (China); Institute of Modern Physics of CAS and Lanzhou University, Research Center for Hadron and CSR Physics, Lanzhou (China); Wei, Ke-Wei [Anyang Normal University, Department of Physics, Anyang (China); Liu, Xiang [Lanzhou University, School of Physical Science and Technology, Lanzhou (China); Institute of Modern Physics of CAS and Lanzhou University, Research Center for Hadron and CSR Physics, Lanzhou (China); Matsuki, Takayuki [Tokyo Kasei University, Tokyo (Japan); Nishina Center, RIKEN, Theoretical Research Division, Saitama (Japan)

    2017-03-15

    In this work, we systematically study the mass spectra and strong decays of 1P and 2S charmed and charmed-strange baryons in the framework of non-relativistic constituent quark models. With the light quark cluster-heavy quark picture, the masses are simply calculated by a potential model. The strong decays are studied by the Eichten-Hill-Quigg decay formula. Masses and decay properties of the well-established 1S and 1P states can be reproduced by our method. Σ{sub c}(2800){sup 0,+,++} can be assigned as a Σ{sub c2}(3/2{sup -}) or Σ{sub c2}(5/2{sup -}) state. We prefer to interpret the signal Σ{sub c}(2850){sup 0} as a 2S(1/2{sup +}) state although at present we cannot thoroughly exclude the possibility that this is the same state as Σ{sub c}(2800){sup 0}. Λ{sub c}(2765){sup +} or Σ{sub c}(2765){sup +} could be explained as the Λ{sub c}{sup +}(2S) state or Σ{sup +}{sub c1}(1/2{sup -}) state, respectively. We propose to measure the branching ratio of B(Σ{sub c}(2455)π)/B(Σ{sub c}(2520)π) in the future, which may disentangle the puzzle of this state. Our results support Ξ{sub c}(2980){sup 0,+} as the first radial excited state of Ξ{sub c}(2470){sup 0,+} with J{sup P} = 1/2{sup +}. The assignment of Ξ{sub c}(2930){sup 0} is analogous to Σ{sub c}(2800){sup 0,+,++}, i.e., a Ξ{sup '}{sub c2}(3/2{sup -}) or Ξ{sup '}{sub c2}(5/2{sup -}) state. In addition, we predict some typical ratios among partial decay widths, which are valuable for experimental search for these missing charmed and charmed-strange baryons. (orig.)

  14. Topics in the theory of neutron star cooling

    International Nuclear Information System (INIS)

    Duncan, R.C. Jr.

    1986-01-01

    The author calculates the neutrino emissivity of interacting, degenerate quark matter, which may make up the dense cores of neutron stars. QCD interactions between quarks are included to first order. The author shows that when massive s-quarks are present in cold quark matter, electrons are not present in equilibrium at densities above a threshold electron extinction density n/sub ex/. This results in a much lower neutrino emissivity epsilon/sub nu/ at high densities than has been previously calculated. Dependences of epsilon/sub nu/ on the strange quark mass m/sub s/ and the QCD coupling constant a/sub c/ are determined for a quark liquid in β-equilibrium. Implications of these calculations for neutron-star cooling are briefly discussed. Eventually, it is shown that neutrino momentum effects may be ignored in neutron star cooling calculations without significant error, even when high-density quark-matter cores are present. Finally considered is the very early cooling epoch, lasting up to ∼1 minutes after formation, when a neutron star is optically thick to neutrinos. It is shown that the coupled equations of neutrino and photon transport in the atmosphere of a sufficiently hot, nascent neutron star do not admit hydrostatic solutions

  15. GRB 130603B: No Compelling Evidence for Neutron Star Merger

    Directory of Open Access Journals (Sweden)

    Shlomo Dado

    2015-01-01

    Full Text Available The near infrared (NIR flare/rebrightening in the afterglow of the short hard gamma ray burst (SHB 130603B measured with the Hubble Space Telescope (HST and an alleged late-time X-ray excess were interpreted as possible evidence of a neutron star merger origin of SHBs. However, the X-ray afterglow that was measured with the Swift XRT and Newton XMM has the canonical behaviour of a synchrotron afterglow produced by a highly relativistic jet. The H-band flux observed with HST 9.41 days after burst is that expected from the measured late-time X-ray afterglow. The late-time flare/rebrightening of the NIR-optical afterglow of SHB 130603B could have been produced also by jet collision with an interstellar density bump. Moreover, SHB plus a kilonova can be produced also by the collapse of a compact star (neutron star, strange star, or quark star to a more compact object due to cooling, loss of angular momentum, or mass accretion.

  16. Strangeness photoproduction at the BGO-OD experiment

    Energy Technology Data Exchange (ETDEWEB)

    Jude, Thomas [Physikalisches Institut, Universitaet Bonn, Nussallee 12, Bonn (Germany); Collaboration: BGO-OD-Collaboration

    2015-07-01

    The BGO-OD experiment at the ELSA accelerator facility uses an energy tagged bremstrahlung photon beam to investigate the internal structure of the nucleon. The setup consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. The BGO-OD is ideal for investigating the photoproduction of hadrons of non-zero strangeness. The high momentum resolution at forward angles covers a kinematic region where t-channel exchange mechanisms play a dominant role. This is complemented by the neutral and charged particle identification in the BGO calorimeter for the identification of hyperon decays. The first part of an extensive physics programme includes measurements of the differential cross section at forward angles for γp → K{sup +}Λ and, using linearly polarised photons, the beam asymmetry, Σ, for γp → K{sup 0}Σ{sup +}. This latter measurement is focussed on the K* threshold region where a cusp-like structure was recently observed in the total cross section. Analysis of these reaction channels for both real and simulated data is presented.

  17. Physics near the strange and charm production thresholds

    International Nuclear Information System (INIS)

    Nagamiya, S.; Bland, L.C.

    1995-01-01

    LISS is a Light-Ion Spin Synchrotron and storage ring that is being considered as an upgrade of the Indiana University Cyclotron Facility. Current plans call for a racetrack design for the ring that will provide variable energy polarized proton and deuteron beams up to a momentum of 16 GeV/c and unpolarized light ions with 3 ≤A ≤ 40 accelerated to comparable rigidities. Experiments would be conducted using both polarized and unpolarized internal targets. The racetrack design for the ring will provide for two ∼100-m long, zero-dispersion straight sections that allow for the installation of sophisticated experimental equipment. The ring design will incorporate the recently developed technologies of Siberian snakes allowing for relatively straightforward acceleration and use of polarized beams for high-precision experiments, electron cooling for shrinking the emittance of the stored beams, and carrier-free polarized internal targets. This talk will focus on that part of the physics Program of the LISS facility associated with the production of strange and charmed quarks. Examples will include the study of the spin-dependence of the A-nucleon scattering length; second-generation associated hyperon production experiments emphasizing polarization transfer and exclusive identification of the produced hyperons (ΛΣ, etc.) with the goal of understanding the dynamical origin of hyperon polarization; and studies of the total charm production cross section in p-p collisions near threshold

  18. Role of the strange quark in the rho(770) meson

    Energy Technology Data Exchange (ETDEWEB)

    Molina Peralta, Raquel [George Washington Univ., Washington, DC (United States); Guo, Dehua [George Washington Univ., Washington, DC (United States); Hu, B. [George Washington Univ., Washington, DC (United States); Alexandru, Andrei; Doering, Michael [George Washington Univ., Washington, DC (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2017-03-01

    Recently, the GWU lattice group has evaluated high-precision phase-shift data for $\\pi\\pi$ scattering in the $I = 1$, $J = 1$ channel. Unitary Chiral Perturbation Theory describes these data well around the resonance region and for different pion masses. Moreover, it allows to extrapolate to the physical point and estimate the effect of the missing $K\\bar{K}$ channel in the two-flavor lattice calculation. The absence of the strange quark in the lattice data leads to a lower $\\rho$ mass, and the analysis with U$\\chi$PT shows that the $K \\bar{K}$ channel indeed pushes the $\\pi\\pi$-scattering phase shift upward, having a surprisingly large effect on the $\\rho$-mass. The inelasticity is shown to be compatible with the experimental data. The analysis is then extended to all available two-flavor lattice simulations and similar mass shifts are observed. Chiral extrapolations of $N_f = 2 + 1$ lattice simulations for the $\\rho(770)$ are also reported.

  19. Unlocking color and flavor in superconducting strange quark matter

    International Nuclear Information System (INIS)

    Alford, Mark; Berges, Juergen; Rajagopal, Krishna

    1999-01-01

    We explore the phase diagram of strongly interacting matter with massless u and d quarks as a function of the strange quark mass m s and the chemical potential μ for baryon number. Neglecting electromagnetism, we describe the different baryonic and quark matter phases at zero temperature. For quark matter, we support our model-independent arguments with a quantitative analysis of a model which uses a four-fermion interaction abstracted from single-gluon exchange. For any finite m s , at sufficiently large μ we find quark matter in a color-flavor-locked state which leaves a global vector-like SU(2) color+L+R symmetry unbroken. As a consequence, chiral symmetry is always broken in sufficiently dense quark matter. As the density is reduced, for sufficiently large m s we observe a first-order transition from the color-flavor-locked phase to color superconducting phase analogous to that in two-flavor QCD. At this unlocking transition chiral symmetry is restored. For realistic values of m s our analysis indicates that chiral symmetry breaking may be present for all densities down to those characteristic of baryonic matter. This supports the idea that quark matter and baryonic matter may be continuously connected in nature. We map the gaps at the quark Fermi surfaces in the high density color-flavor-locked phase onto gaps at the baryon Fermi surfaces at low densities

  20. The Strange Case of Billy Biswas: Two conflicting realities

    Directory of Open Access Journals (Sweden)

    Bikki Anupama

    2017-09-01

    Full Text Available Arun Joshi presents socio-cultural conflicts between two different societies. One society is material driven and backed by the modern state apparatus like police, courts, etc. while the other is subsistence driven and is at the bottom in the hierarchy of the modern state. Indian tribal societies have been exploited right from the colonial period into the post-independence times. These two societies differ as follows: the tribal society lives on subsistence looks at Nature as a space for socio-economic, political, cultural and community, while the urban materialistic world perceives Nature as a resource to be exploited. This primordial difference has manifested as a socio-cultural conflict between these two societies. This may be due to the mutually exclusive and incorrigible nature of their social constructs which trigger perceptual obfuscation of symbiotic living.  What appears to be an objective reality for one appears as subjective to the other and vice versa. This paper studies the strangeness of Billy Biswas, the protagonist of the novel in the socio-cultural milieu of conflicting realities.

  1. The Art of Reflection: Turning the Strange into the Familiar.

    Science.gov (United States)

    Weingarten, Kaethe

    2016-06-01

    There are a great many useful articles on the dynamics and pragmatics of reflecting teams but few articles address what constitutes a good or inept reflection and why. I provide a conceptual model for thinking about what a good reflection does, distinguishing it from a nice reflection. With some further refinements in place, I then illustrate how reflections can be part of any relationship, not just clinical ones. We have opportunities to make them and to recognize when others make them to us. By using examples from my personal life-as a grandmother, daughter, radio listener, cancer survivor, and client-I attempt to ease the personal/professional binary, a project of mine for the last 35 years. In the second part of the article, I address how writing can serve reflection. Although best offered at the moment one is called for, it is never too late for a reflection. Writing allows people to offer reflections after the fact to those who have shared their stories. Sometimes, it is to ourselves we offer those reflections, when the reflector has long since dropped the thread of obligation or interest. I provide an example of working with iconic imagery to unpack meaning so that reflection can eventually take place, allowing integration to proceed, facilitating the strange becoming the familiar. © 2015 Family Process Institute.

  2. Search for the Charmed Strange Baryon A$^{o}$

    CERN Multimedia

    2002-01-01

    The aim of the experiment is to search for inclusive production of the charmed strange baryon A|0 using @S|- with a momentum of 135 GeV/c on a Be-target. A|0 with lab-momenta between 70-120 GeV/c will be accepted, corresponding to X(A|0) $>$ 0.5. \\\\ \\\\ The apparatus is a modified version of the one used for WA42. The incoming @S|- are identified by a DISC Cerenkov counter. The A|0 detection is restricted to decay channels which contains only charged particles in the final state (e.g. A|0 @A @L K|-@p|+). \\\\ \\\\ The decay products are analysed in a magnetic spectrometer equipped with multiwire proportional chambers (B,C,D,E) and drift chambers (DC). Two multicell gas Cerenkov counters (C1,C2) allow the separation of K's and p's from @p's. A second magnet (SM2) reduces the geometrical overlap of @p's and heavier particles in the Cerenkov counters due to their different momentum spectra. The scintillator hodoscopes H^4 and H^5 and the chambers E and F behind SM2 allow a geometrical correlation of tracks with the C...

  3. Critical charges on strange quark nuggets and other extended objects

    International Nuclear Information System (INIS)

    Dicus, Duane A.; Repko, Wayne W.; Teplitz, V. L.

    2008-01-01

    We investigate the behavior of the critical charge for spontaneous pair production, Z C , defined as the charge at which the total energy of a K-shell electron is E=-m e , as a function of the radius R of the charge distribution. Our approach is to solve the Dirac equation for a potential V(r) consisting of a spherically symmetrical charge distribution of radius R and a Coulomb tail. For a spherical shell distribution of the type usually associated with color-flavor locked strange quark nuggets, we confirm the relation Z C =0.71R (fm) for sufficiently large R obtained by Madsen, who used an approach based on the Thomas-Fermi model. We also present results for a uniformly charged sphere and again find that Z C ∼R for large enough R. Also discussed is the behavior of Z C when simple ad hoc modifications are made to the potential for 0≤r< R.

  4. Strangeness production in nucleus-nucleus collisions: An experimental review

    International Nuclear Information System (INIS)

    Odyniec, G.

    1990-12-01

    In experiments with oxygen (60 and 200 GeV/N) and sulphur (200 GeV/N) ions at CERNSPS, large energy densities of the order of 2--3 GeV/fm 3 have been observed, which according to QCD calculations, satisfy necessary conditions for the formation of a quark gluon plasma (QGP) phase. Under such conditions, colour would no longer be confined to hadronic dimensions, and quarks and gluons will propagate freely throughout an extended volume. Somehow lower energy densities, of the order of 0.7--1 GeV/fm 3 , were observed in AGS experiments with 15 GeV/N silicon beams and heavy targets. These energy densities might be adequate for investigations of the pre-equilibrium stage, during which the momentum space distribution has been degradated from its initial value but is not yet thermal. First experimental results, available now, show promise of seeing signs of a new phase of matter. In this review the current status of the selective experimental results on strange-particle production, which are relevant to equilibration and QGP formation in nucleus-nucleus collisions, is presented

  5. Strange b baryon production and lifetime in Z decays

    Science.gov (United States)

    Buskulic, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Lucotte, A.; Minard, M.-N.; Nief, J.-Y.; Odier, P.; Pietrzyk, B.; Casado, M. P.; Chmeissani, M.; Crespo, J. M.; Delfino, M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Juste, A.; Martinez, M.; Orteu, S.; Padilla, C.; Park, I. C.; Pascual, A.; Perlas, J. A.; Riu, I.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; de Palma, M.; Gelao, G.; Girone, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Marinelli, N.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Alemany, R.; Bazarko, A. O.; Bonvicini, G.; Cattaneo, M.; Comas, P.; Coyle, P.; Drevermann, H.; Forty, R. W.; Frank, M.; Hagelberg, R.; Harvey, J.; Janot, P.; Jost, B.; Kneringer, E.; Knobloch, J.; Lehraus, I.; Lutters, G.; Martin, E. B.; Mato, P.; Minten, A.; Miquel, R.; Mir, Ll. M.; Moneta, L.; Oest, T.; Pacheco, A.; Pusztaszeri, J.-F.; Ranjard, F.; Rensing, P.; Rolandi, L.; Schlatter, D.; Schmelling, M.; Schmitt, M.; Schneider, O.; Tejessy, W.; Tomalin, I. R.; Venturi, A.; Wachsmuth, H.; Wagner, A.; Ajaltouni, Z.; Barrès, A.; Boyer, C.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Rosnet, P.; Rossignol, J.-M.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Nilsson, B. S.; Rensch, B.; Wäänänen, A.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Rougé, A.; Rumpf, M.; Valassi, A.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Focardi, E.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Jaffe, D. E.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Casper, D.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Curtis, L.; Dorris, S. J.; Halley, A. W.; Knowles, I. G.; Lynch, J. G.; O'Shea, V.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Teixeira-Dias, P.; Thompson, A. S.; Thomson, F.; Thorn, S.; Turnbull, R. M.; Becker, U.; Geweniger, C.; Graefe, G.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E. E.; Putzer, A.; Schmidt, M.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, S.; Wunsch, M.; Abbaneo, D.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Dornan, P. J.; Moutoussi, A.; Nash, J.; Sedgbeer, J. K.; Stacey, A. M.; Williams, M. D.; Dissertori, G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Betteridge, A. P.; Bowdery, C. K.; Colrain, P.; Crawford, G.; Finch, A. J.; Foster, F.; Hughes, G.; Sloan, T.; Williams, M. I.; Galla, A.; Giehl, I.; Greene, A. M.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.-G.; van Gemmeren, P.; Zeitnitz, C.; Aubert, J. J.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Diaconu, C.; Etienne, F.; Konstantinidis, N.; Payre, P.; Rousseau, D.; Talby, M.; Sadouki, A.; Thulasidas, M.; Trabelsi, K.; Aleppo, M.; Ragusa, F.; Abt, I.; Assmann, R.; Bauer, C.; Blum, W.; Dietl, H.; Dydak, F.; Ganis, G.; Gotzhein, C.; Jakobs, K.; Kroha, H.; Lütjens, G.; Lutz, G.; Männer, W.; Moser, H.-G.; Richter, R.; Rosado-Schlosser, A.; Schael, S.; Settles, R.; Seywerd, H.; Denis, R. St.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Choi, Y.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Höcker, A.; Jacholkowska, A.; Jacquet, M.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Nikolic, I.; Park, H. J.; Schune, M.-H.; Simion, S.; Veillet, J.-J.; Videau, I.; Zerwas, D.; Azzurri, P.; Bagliesi, G.; Batignani, G.; Bettarini, S.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Sciabà, A.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Vannini, C.; Verdini, P. G.; Walsh, J.; Blair, G. A.; Bryant, L. M.; Cerutti, F.; Chambers, J. T.; Gao, Y.; Green, M. G.; Medcalf, T.; Perrodo, P.; Strong, J. A.; von Wimmersperg-Toeller, J. H.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Maley, P.; Norton, P. R.; Thompson, J. C.; Wright, A. E.; Bloch-Devaux, B.; Colas, P.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J.-F.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Black, S. N.; Dann, J. H.; Johnson, R. P.; Kim, H. Y.; Litke, A. M.; McNeil, M. A.; Taylor, G.; Booth, C. N.; Boswell, R.; Brew, C. A. J.; Cartwright, S.; Combley, F.; Koksal, A.; Letho, M.; Newton, W. M.; Reeve, J.; Thompson, L. F.; Böhrer, A.; Brandt, S.; Büscher, V.; Cowan, G.; Grupen, C.; Minguet-Rodriguez, J.; Rivera, F.; Saraiva, P.; Smolik, L.; Stephan, F.; Apollonio, M.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Rothberg, J.; Wasserbaech, S.; Armstrong, S. R.; Elmer, P.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; González, S.; Grahl, J.; Greening, T. C.; Hayes, O. J.; Hu, H.; McNamara, P. A.; Nachtman, J. M.; Orejudos, W.; Pan, Y. B.; Saadi, Y.; Scott, I. J.; Walsh, A. M.; Wu, Sau Lan; Wu, X.; Yamartino, J. M.; Zheng, M.; Zobernig, G.; Aleph Collaboration

    1996-02-01

    In a data sample of approximately four million hadronic Z decays recorded with the ALEPH detector from 1990 to 1995, a search for the strange b baryon Ξb is performed with a study of Ξ-lepton correlations. Forty-four events with same sign Ξ-ℓ - combinations are found whereas 8.4 are expected based on the rate of opposite sign Ξ-ℓ + combinations. This significant excess is interpreted as evidence for Ξb semileptonic decays. The measured product branching ratio is Br(b → Ξ b) × Br(Ξ b → X cXℓ -overlineν ℓ) × Br(X c → Ξ -X‧) = (5.4±1.1(stat) ± 0.8(syst)) × 10 -4 per lepton species, averaged over electrons and muons, with X c a charmed baryon. The Ξb lifetime is measured to be τΞb = 1.35 -0.28+0.37(stat) -0.17+0.15(syst) ps.

  6. Testing the doubly charged charm-strange tetraquarks

    Science.gov (United States)

    Agaev, S. S.; Azizi, K.; Sundu, H.

    2018-02-01

    The spectroscopic parameters and decay channels of the doubly charged scalar, pseudoscalar and axial-vector charm-strange tetraquarks Z_{ \\overline{c}s}=[sd][\\overline{u} \\overline{c}] are explored within framework of the QCD sum rule method. The masses and current couplings of these diquark-antidiquark states are calculated by means of two-point correlation functions and taking into account the vacuum condensates up to eight dimensions. To compute the strong couplings of Z_{\\overline{c}s} states with D, Ds, D^{*}, Ds^{*}, D_{s1}(2460), D_{s0}^{*}(2317), π and K mesons we use QCD light-cone sum rules and evaluate width of their S- and P-wave decays to a pair of negatively charged conventional mesons: For the scalar state Z_{\\overline{c}s}→ D_s π , DK, D_{s1}(2460)π , for the pseudoscalar state Z_{\\overline{c}s} → Ds^{*}π , D^{*}K, D_{s0}^{*}(2317)π , and for the axial-vector state Z_{\\overline{c}s} → Ds^{*}π , D^{*}K, D_{s1}(2460)π decays are investigated. Obtained predictions for the spectroscopic parameters and decay widths of the Z_{\\overline{c}s} tetraquarks may be useful for experimental investigations of the doubly charged exotic hadrons.

  7. O stars and Wolf-Rayet stars

    International Nuclear Information System (INIS)

    Conti, P.S.; Underhill, A.B.; Jordan, S.; Thomas, R.

    1988-01-01

    Basic information is given about O and Wolf-Rayet stars indicating how these stars are defined and what their chief observable properties are. Part 2 of the volume discussed four related themes pertaining to the hottest and most luminous stars. Presented are: an observational overview of the spectroscopic classification and extrinsic properties of O and Wolf-Rayet stars; the intrinsic parameters of luminosity, effective temperature, mass, and composition of the stars, and a discussion of their viability; stellar wind properties; and the related issues concerning the efforts of stellar radiation and wind on the immediate interstellar environment are presented

  8. O stars and Wolf-Rayet stars

    Science.gov (United States)

    Conti, Peter S.; Underhill, Anne B.; Jordan, Stuart (Editor); Thomas, Richard (Editor)

    1988-01-01

    Basic information is given about O and Wolf-Rayet stars indicating how these stars are defined and what their chief observable properties are. Part 2 of the volume discussed four related themes pertaining to the hottest and most luminous stars. Presented are: an observational overview of the spectroscopic classification and extrinsic properties of O and Wolf-Rayet stars; the intrinsic parameters of luminosity, effective temperature, mass, and composition of the stars, and a discussion of their viability; stellar wind properties; and the related issues concerning the efforts of stellar radiation and wind on the immediate interstellar environment are presented.

  9. Shock wave produced by hadron-quark phase transition in neutron star

    Energy Technology Data Exchange (ETDEWEB)

    Gustavo de Almeida, Luis, E-mail: lgalmeida@cbpf.br [Universidade Federal do Acre – Campus Floresta, Estrada do Canela Fina, km 12, CEP 69980-000, Cruzeiro do Sul, AC (Brazil); Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150, CEP 22290-180, Rio de Janeiro, RJ (Brazil); Duarte, Sérgio José Barbosa, E-mail: sbd@cbpf.br [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150, CEP 22290-180, Rio de Janeiro, RJ (Brazil); Rodrigues, Hilário, E-mail: harg.astrophys@gmail.com [Centro Federal de Educação Tecnológica Celso Suckow da Fonseca Av. Maracanã, 229, CEP 20271-110, Rio de Janeiro, RJ (Brazil)

    2015-12-17

    In this work we present a schematic description of the detonation wave in hadronic matter inside a neutron star core. We have used a simplified two shells model where the inner shell medium is initially composed of a small lump of strange quark matter surrounded by a large outer shell composed of hadronic matter. We have utilized an equation of state (EOS) based on Relativistic Mean Field Theory with the parameter set NL3 to describe the nuclear and subnuclear phases. We use the MIT bag model to describe the strange quark matter. The hadron-quark phase transition actually induces highly non equilibrium modes, which may become a detonation process (faster) or a burning process (slower). The main purpose of the work is to study the formation of a remnant quark star and the possibility of mass ejection caused by the hadron-quark phase transition. We have found that the total amount of ejected mass is dependant of the bag constant utilized in the strange matter description.

  10. Strange-face Illusions During Interpersonal-Gazing and Personality Differences of Spirituality.

    Science.gov (United States)

    Caputo, Giovanni B

    Strange-face illusions are produced when two individuals gaze at each other in the eyes in low illumination for more than a few minutes. Usually, the members of the dyad perceive numinous apparitions, like the other's face deformations and perception of a stranger or a monster in place of the other, and feel a short lasting dissociation. In the present experiment, the influence of the spirituality personality trait on strength and number of strange-face illusions was investigated. Thirty participants were preliminarily tested for superstition (Paranormal Belief Scale, PBS) and spirituality (Spiritual Transcendence Scale, STS); then, they were randomly assigned to 15 dyads. Dyads performed the intersubjective gazing task for 10 minutes and, finally, strange-face illusions (measured through the Strange-Face Questionnaire, SFQ) were evaluated. The first finding was that SFQ was independent of PBS; hence, strange-face illusions during intersubjective gazing are authentically perceptual, hallucination-like phenomena, and not due to superstition. The second finding was that SFQ depended on the spiritual-universality scale of STS (a belief in the unitive nature of life; e.g., "there is a higher plane of consciousness or spirituality that binds all people") and the two variables were negatively correlated. Thus, strange-face illusions, in particular monstrous apparitions, could potentially disrupt binding among human beings. Strange-face illusions can be considered as 'projections' of the subject's unconscious into the other's face. In conclusion, intersubjective gazing at low illumination can be a tool for conscious integration of unconscious 'shadows of the Self' in order to reach completeness of the Self. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Egyptian "Star Clocks"

    Science.gov (United States)

    Symons, Sarah

    Diagonal, transit, and Ramesside star clocks are tables of astronomical information occasionally found in ancient Egyptian temples, tombs, and papyri. The tables represent the motions of selected stars (decans and hour stars) throughout the Egyptian civil year. Analysis of star clocks leads to greater understanding of ancient Egyptian constellations, ritual astronomical activities, observational practices, and pharaonic chronology.

  12. MAGNETIC FIELDS OF STARS

    OpenAIRE

    Bychkov, V. D.; Bychkova, L. V.; Madej, J.

    2008-01-01

    Now it is known about 1212 stars of the main sequence and giants (from them 610 stars - it is chemically peculiarity (CP) stars) for which direct measurements of magnetic fields were spent (Bychkov et al.,2008). Let's consider, what representations were generated about magnetic fields (MT) of stars on the basis of available observations data.

  13. Quantum-state discrimination

    International Nuclear Information System (INIS)

    Roa, Luis; Retamal, Juan Carlos; Saavedra, Carlos

    2002-01-01

    A proposal for a physical implementation of a quantum-state discrimination protocol using an ion in a linear trap is studied, where two nonorthogonal quantum states are codified using two electronic states of the ion. In addition, a protocol is given for discriminating superpositions of nonorthogonal entangled states between ions inside widely separated optical cavities. The discrimination protocol is extended to the case of N linearly independent nonorthogonal quantum states lying in a space of 2N-1 dimensions

  14. Socially-Tolerable Discrimination

    OpenAIRE

    Amegashie, J. Atsu

    2008-01-01

    History is replete with overt discrimination on the basis of race, gender, age, citizenship, ethnicity, marital status, academic performance, health status, volume of market transactions, religion, sexual orientation, etc. However, these forms of discrimination are not equally tolerable. For example, discrimination based on immutable or prohibitively unalterable characteristics such as race, gender, or ethnicity is much less acceptable. Why? I develop a simple rent-seeking model of conflict w...

  15. Compact stars

    Science.gov (United States)

    Estevez-Delgado, Gabino; Estevez-Delgado, Joaquin

    2018-05-01

    An analysis and construction is presented for a stellar model characterized by two parameters (w, n) associated with the compactness ratio and anisotropy, respectively. The reliability range for the parameter w ≤ 1.97981225149 corresponds with a compactness ratio u ≤ 0.2644959374, the density and pressures are positive, regular and monotonic decrescent functions, the radial and tangential speed of sound are lower than the light speed, moreover, than the plausible stability. The behavior of the speeds of sound are determinate for the anisotropy parameter n, admitting a subinterval where the speeds are monotonic crescent functions and other where we have monotonic decrescent functions for the same speeds, both cases describing a compact object that is also potentially stable. In the bigger value for the observational mass M = 2.05 M⊙ and radii R = 12.957 Km for the star PSR J0348+0432, the model indicates that the maximum central density ρc = 1.283820319 × 1018 Kg/m3 corresponds to the maximum value of the anisotropy parameter and the radial and tangential speed of the sound are monotonic decrescent functions.

  16. Neutron Stars and NuSTAR

    Science.gov (United States)

    Bhalerao, Varun

    2012-05-01

    My thesis centers around the study of neutron stars, especially those in massive binary systems. To this end, it has two distinct components: the observational study of neutron stars in massive binaries with a goal of measuring neutron star masses and participation in NuSTAR, the first imaging hard X-ray mission, one that is extremely well suited to the study of massive binaries and compact objects in our Galaxy. The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer mission that will carry the first focusing high energy X-ray telescope to orbit. NuSTAR has an order-of-magnitude better angular resolution and has two orders of magnitude higher sensitivity than any currently orbiting hard X-ray telescope. I worked to develop, calibrate, and test CdZnTe detectors for NuSTAR. I describe the CdZnTe detectors in comprehensive detail here - from readout procedures to data analysis. Detailed calibration of detectors is necessary for analyzing astrophysical source data obtained by the NuSTAR. I discuss the design and implementation of an automated setup for calibrating flight detectors, followed by calibration procedures and results. Neutron stars are an excellent probe of fundamental physics. The maximum mass of a neutron star can put stringent constraints on the equation of state of matter at extreme pressures and densities. From an astrophysical perspective, there are several open questions in our understanding of neutron stars. What are the birth masses of neutron stars? How do they change in binary evolution? Are there multiple mechanisms for the formation of neutron stars? Measuring masses of neutron stars helps answer these questions. Neutron stars in high-mass X-ray binaries have masses close to their birth mass, providing an opportunity to disentangle the role of "nature" and "nurture" in the observed mass distributions. In 2006, masses had been measured for only six such objects, but this small sample showed the greatest diversity in masses

  17. Strangeness freeze-out: role of system size and missing resonances

    Directory of Open Access Journals (Sweden)

    Chatterjee Sandeep

    2018-01-01

    Full Text Available The conventional approach to treat strangeness freezeout has been to consider a unified freezeout scheme where strangeness freezes out along with the nonstrange hadrons (1CFO, with or without an additional parameter accounting for out-of-equilibrium strangeness production (γS. Several alternate scenarios have been formulated lately. Here, we will focus on flavor dependent freezeout with early freezeout of strangeness (2CFO in comparison to 1CFO and its variants with respect to the roles played by the system size and missing resonances predicted by different theoretical approaches but yet to be seen in experiments. In contrast to the performance of 1CFO with/without γS that is insensitive to system size, 2CFO exhibits a clear system size dependence-while for Pb+Pb the χ2/NDF is around 0-2, for smaller system size in p+Pb and p+p, the χ2/NDF> 5 and larger than 1CFO+γS. This clearly shows a system size dependence of the preference for the freezeout scheme, while 2CFO is preferred in Pb+Pb, 1CFO+γS is preferred in p+Pb and p+p. We have further investigated the role of the missing resonances on strangeness freezeout across SPS to LHC beam energies.

  18. The neutron star mass distribution

    Energy Technology Data Exchange (ETDEWEB)

    Kiziltan, Bülent [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Kottas, Athanasios; De Yoreo, Maria [Department of Applied Mathematics and Statistics, University of California, Santa Cruz, CA 95064 (United States); Thorsett, Stephen E., E-mail: bkiziltan@cfa.harvard.edu [Department of Astronomy and Astrophysics, University of California and UCO/Lick Observatory, Santa Cruz, CA 95064 (United States)

    2013-11-20

    In recent years, the number of pulsars with secure mass measurements has increased to a level that allows us to probe the underlying neutron star (NS) mass distribution in detail. We critically review the radio pulsar mass measurements. For the first time, we are able to analyze a sizable population of NSs with a flexible modeling approach that can effectively accommodate a skewed underlying distribution and asymmetric measurement errors. We find that NSs that have evolved through different evolutionary paths reflect distinctive signatures through dissimilar distribution peak and mass cutoff values. NSs in double NS and NS-white dwarf (WD) systems show consistent respective peaks at 1.33 M {sub ☉} and 1.55 M {sub ☉}, suggesting significant mass accretion (Δm ≈ 0.22 M {sub ☉}) has occurred during the spin-up phase. The width of the mass distribution implied by double NS systems is indicative of a tight initial mass function while the inferred mass range is significantly wider for NSs that have gone through recycling. We find a mass cutoff at ∼2.1 M {sub ☉} for NSs with WD companions, which establishes a firm lower bound for the maximum NS mass. This rules out the majority of strange quark and soft equation of state models as viable configurations for NS matter. The lack of truncation close to the maximum mass cutoff along with the skewed nature of the inferred mass distribution both enforce the suggestion that the 2.1 M {sub ☉} limit is set by evolutionary constraints rather than nuclear physics or general relativity, and the existence of rare supermassive NSs is possible.

  19. 'The Strange Case of Angelica': affinity between Fantastic and Documental

    Directory of Open Access Journals (Sweden)

    Rita Benis

    2017-01-01

    Full Text Available In 2010, Manoel de Oliveira films The Strange Case of Angélica, a project from the early fifties of the past century. In it, the confrontation between the documentary side of the film (the sequences where the protagonist, Isaac, photographs the workers in the vineyards and the fantastic sequences (the episodes with the ghost of Angelica seems to indicate an affinity. That "shadow of resemblance" Petrarch spoke about to his close friend Giovanni Boccaccio: "... he who imitates must proceed in such a way that what he does is similar but not equal, and that the likeness is not that which exists between the original and the copy, that the more similar the more it is praiseworthy, but instead a likeness which one finds in the similarities between a father and a son, among which, though much difference is made in the aspect, there is, however, as a shadow of resemblance, which the painters call 'aire' (... "(apud Rodrigues 2003: 5. A "family air" as a living correlation that comes to our encounter and which is felt as an immediate understanding (and not as definable evidence. In the film, the shiver that assaults us through the apparition of Angelica seems to announce something that goes beyond this same vision: the eminence of the disappearance of the vineyard workers and their gestures, a loss of connection between Man and Nature. The present affinity - Angelica / diggers - is mirrored in Isaac's immense melancholy, the only person apparently capable of perceiving the landscape, the "air" that this relationship evokes. The whole film is crossed by the glimpse of this indefinable kinship, by the porosity between the sensitive world and the spectral world, the permanent interweaving of visibilities / invisibilities that allow us access to this other cinematographic space-time, more percept than visible, in which, according to Manoel de Oliveira, the phantom of physical reality reveals itself "more real, however, than reality itself" (Baecque and

  20. Strange history: the fall of Rome explained in Hereditas.

    Science.gov (United States)

    Bengtsson, Bengt O

    2014-12-01

    In 1921 Hereditas published an article on the fall of Rome written by the famous classical scholar Martin P:son Nilsson. Why was a paper on this unexpected topic printed in the newly founded journal? To Nilsson, the demise of the Roman Empire was explained by the "bastardization" occurring between "races" from different parts of the realm. Offspring from mixed couples were of a less stable "type" than their parents, due to the breaking up by recombination of the original hereditary dispositions, which led to a general loss of competence to rule and govern. Thus, the "hardness" of human genes, together with their recombination, was - according to Nilsson - the main cause of the fall of Rome. Nilsson's argument is not particularly convincingly presented. Human "races" are taken to have the same genetic structure as inbred crop strains, and Nilsson believes in a metaphysical unity between the individual and the race to which it belongs. However, in my view, Martin P:son Nilsson and his friend Herman Nilsson-Ehle had wider aims with the article than to explain a historical event. The article can be read as indicating strong support from the classical human sciences to the ambitious new science of genetics. Support is also transferred from genetics to the conservative worldview, where the immutability and inflexibility of the Mendelian genes are used to strengthen the wish for greater stability in politics and life. The strange article in Hereditas can, thus, be read as an early instance in the - still ongoing - tug-of-war between the conservative and the liberal ideological poles over how genetic results best are socially interpreted. © 2015 The Authors.

  1. Hypernuclei and strangeness physics programme at J-PARC

    International Nuclear Information System (INIS)

    Nagae, Tomofumi

    2009-01-01

    Full text: The construction of Japan Proton Accelerator Research Complex (J-PARC) is completed in 2009. The J-PARC accelerators consist of a 181-MeV proton linac, a 3-GeV rapid-cycling proton synchrotron, and a 50-GeV main proton synchrotron. Now, the 3-GeV proton beam is used to produce spallation neutrons and slow muons for materials and life sciences. The 30-GeV proton beam from the main ring is used to produce high-intensity kaon beams and neutrino beam. Beam commissioning of the slow-extraction beam from the J- PARC main proton synchrotron started in January, 2009. The beam was successfully extracted and transported to the Hadron Experimental Hall on January 27. The first secondary-beam production was confirmed on February 11 at the K1.8-branch beam line in the hall. Although we need a lot of work to be completed before the beam would be available for experimental users, we believe this is the start of the J-PARC era to open new research fields in strangeness nuclear physics. The K - beams with the highest intensity in the world enable us to carry out various interesting experimental subjects; the (K - , K + ) missing-mass spectroscopy to discover hypernuclei, hypernuclear gamma-ray spectroscopy, search for kaonic nuclei, and so on. New detector systems such as the SKS+ spectrometer, Hyperball-J detector, and Cylindrical Detector System (CDS) are now in preparation. Present status of the experiments, our initial physics goals at J-PARC and the perspectives are discussed

  2. Testing the doubly charged charm-strange tetraquarks

    Energy Technology Data Exchange (ETDEWEB)

    Agaev, S.S. [Kocaeli University, Department of Physics, Izmit (Turkey); Baku State University, Institute for Physical Problems, Baku (Azerbaijan); Azizi, K. [Dogus University, Department of Physics, Istanbul (Turkey); Institute for Research in Fundamental Sciences (IPM), School of Physics, Tehran (Iran, Islamic Republic of); Sundu, H. [Kocaeli University, Department of Physics, Izmit (Turkey)

    2018-02-15

    The spectroscopic parameters and decay channels of the doubly charged scalar, pseudoscalar and axial-vector charm-strange tetraquarks Z {sub anti} {sub cs} = [sd][uc] are explored within framework of the QCD sum rule method. The masses and current couplings of these diquark-antidiquark states are calculated by means of two-point correlation functions and taking into account the vacuum condensates up to eight dimensions. To compute the strong couplings of Z {sub anti} {sub cs} states with D, D{sub s}, D*,D{sub s}{sup *}, D{sub s1}(2460), D{sub s0}{sup *}(2317), π and K mesons we use QCD light-cone sum rules and evaluate width of their S- and P-wave decays to a pair of negatively charged conventional mesons: For the scalar state Z {sub anti} {sub cs} → D{sub s}π,DK, D{sub s1}(2460)π, for the pseudoscalar state Z {sub anti} {sub cs} → D{sub s}{sup *}π, D*K, D{sub s0}{sup *}(2317)π, and for the axial-vector state Z {sub anti} {sub cs} → D{sub s}{sup *}π, D*K, D{sub s1}(2460)π decays are investigated. Obtained predictions for the spectroscopic parameters and decay widths of the Z {sub anti} {sub cs} tetraquarks may be useful for experimental investigations of the doubly charged exotic hadrons. (orig.)

  3. The Strange Case of OGLE-SMC-ECL-0277

    Czech Academy of Sciences Publication Activity Database

    Zasche, P.; Wolf, M.; Vraštil, J.; Fatka, P.; Hornoch, Kamil; Janák, Z.; Janík, J.; Kortusová, Eva; Kurfürst, P.; Kušnirák, Peter; Paunzen, E.; Řezba, Luděk; Votruba, Viktor; Zejda, M.; Zielinski, P.

    2017-01-01

    Roč. 67, č. 3 (2017), s. 243-255 ISSN 0001-5237 R&D Projects: GA MŠk(CZ) LG15010 Grant - others:GA ČR(CZ) GA15-02112S Institutional support: RVO:67985815 Keywords : binaries eclipsing * stars * fundamental parameters Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 3.043, year: 2016

  4. Generalized isothermal models with strange equation of state

    Indian Academy of Sciences (India)

    intention to study the Einstein–Maxwell system with a linear equation of state with ... It is our intention to model the interior of a dense realistic star with a general ... The definition m(r) = 1. 2. ∫ r. 0 ω2ρ(ω)dω. (14) represents the mass contained within a radius r which is a useful physical quantity. The mass function (14) has ...

  5. INTERSECTIONAL DISCRIMINATION AGAINST CHILDREN

    DEFF Research Database (Denmark)

    Ravnbøl, Camilla Ida

    This paper adds a perspective to existing research on child protection by engaging in a debate on intersectional discrimination and its relationship to child protection. The paper has a twofold objective, (1) to further establish intersectionality as a concept to address discrimination against...... children, and (2) to illustrate the importance of addressing intersectionality within rights-based programmes of child protection....

  6. Discrimination and delusional ideation.

    Science.gov (United States)

    Janssen, I; Hanssen, M; Bak, M; Bijl, R V; de Graaf, R; Vollebergh, W; McKenzie, K; van Os, J

    2003-01-01

    In the UK and The Netherlands, people with high rates of psychosis are chronically exposed to discrimination. To test whether perceived discrimination is associated longitudinally with onset of psychosis. A 3-year prospective study of cohorts with no history of psychosis and differential rates of reported discrimination on the basis of age, gender, disability, appearance, skin colour or ethnicity and sexual orientation was conducted in the Dutch general population (n=4076). The main outcome was onset of psychotic symptoms (delusions and hallucinations). The rate of delusional ideation was 0.5% (n=19) in those who did not report discrimination, 0.9% (n=4) in those who reported discrimination in one domain, and 2.7% (n=3) in those who reported discrimination in more than one domain (exact P=0.027). This association remained after adjustment for possible confounders. No association was found between baseline discrimination and onset of hallucinatory experiences. Perceived discrimination may induce delusional ideation and thus contribute to the high observed rates of psychotic disorder in exposed minority populations.

  7. Discrimination and delusional ideation

    NARCIS (Netherlands)

    Janssen, I.C.M.; Hanssen, M.S.S.; Bak, M.L.F.J.; Bijl, R.V.; Graaf, R. de; Vollebergh, W.A.M.; McKenzie, K.; Os, J. van

    2003-01-01

    Background In the UK and The Netherlands, people with high rates of psychosis are chronically exposed to discrimination. Aims To test whether perceived discrimination is associated longitudinally with onset of psychosis. Method A 3-year prospective study of cohorts with no history of psychosis and

  8. Flash-Type Discrimination

    Science.gov (United States)

    Koshak, William J.

    2010-01-01

    This viewgraph presentation describes the significant progress made in the flash-type discrimination algorithm development. The contents include: 1) Highlights of Progress for GLM-R3 Flash-Type discrimination Algorithm Development; 2) Maximum Group Area (MGA) Data; 3) Retrieval Errors from Simulations; and 4) Preliminary Global-scale Retrieval.

  9. Discrimination against Black Students

    Science.gov (United States)

    Aloud, Ashwaq; Alsulayyim, Maryam

    2016-01-01

    Discrimination is a structured way of abusing people based on racial differences, hence barring them from accessing wealth, political participation and engagement in many spheres of human life. Racism and discrimination are inherently rooted in institutions in the society, the problem has spread across many social segments of the society including…

  10. Digital voltage discriminator

    International Nuclear Information System (INIS)

    Zhou Zhicheng

    1992-01-01

    A digital voltage discriminator is described, which is synthesized by digital comparator and ADC. The threshold is program controllable with high stability. Digital region of confusion is approximately equal to 1.5 LSB. This discriminator has a single channel analyzer function model with channel width of 1.5 LSB

  11. Thin accretion disks around cold Bose-Einstein condensate stars

    Energy Technology Data Exchange (ETDEWEB)

    Danila, Bogdan [Babes-Bolyai University, Department of Physics, Cluj-Napoca (Romania); Harko, Tiberiu [University College London, Department of Mathematics, London (United Kingdom); Kovacs, Zoltan

    2015-05-15

    Due to their superfluid properties some compact astrophysical objects, like neutron or quark stars, may contain a significant part of their matter in the form of a Bose-Einstein condensate (BEC). Observationally distinguishing between neutron/quark stars and BEC stars is a major challenge for this latter theoretical model. An observational possibility of indirectly distinguishing BEC stars from neutron/quark stars is through the study of the thin accretion disks around compact general relativistic objects. In the present paper, we perform a detailed comparative study of the electromagnetic and thermodynamic properties of the thin accretion disks around rapidly rotating BEC stars, neutron stars and quark stars, respectively. Due to the differences in the exterior geometry, the thermodynamic and electromagnetic properties of the disks (energy flux, temperature distribution, equilibrium radiation spectrum, and efficiency of energy conversion) are different for these classes of compact objects. Hence in this preliminary study we have pointed out some astrophysical signatures that may allow one to observationally discriminate between BEC stars and neutron/quark stars. (orig.)

  12. Introduction to integral discriminants

    International Nuclear Information System (INIS)

    Morozov, A.; Shakirov, Sh.

    2009-01-01

    The simplest partition function, associated with homogeneous symmetric forms S of degree r in n variables, is integral discriminant J n|r (S) = ∫e -S(x 1 ,...,x n ) dx 1 ...dx n . Actually, S-dependence remains the same if e -S in the integrand is substituted by arbitrary function f(S), i.e. integral discriminant is a characteristic of the form S itself, and not of the averaging procedure. The aim of the present paper is to calculate J n|r in a number of non-Gaussian cases. Using Ward identities - linear differential equations, satisfied by integral discriminants - we calculate J 2|3 ,J 2|4 ,J 2|5 and J 3|3 . In all these examples, integral discriminant appears to be a generalized hypergeometric function. It depends on several SL(n) invariants of S, with essential singularities controlled by the ordinary algebraic discriminant of S.

  13. Giant CP stars

    International Nuclear Information System (INIS)

    Loden, L.O.; Sundman, A.

    1989-01-01

    This study is part of an investigation of the possibility of using chemically peculiar (CP) stars to map local galactic structure. Correct luminosities of these stars are therefore crucial. CP stars are generally regarded as main-sequence or near-main-sequence objects. However, some CP stars have been classified as giants. A selection of stars, classified in literature as CP giants, are compared to normal stars in the same effective temperature interval and to ordinary 'non giant' CP stars. There is no clear confirmation of a higher luminosity for 'CP giants', than for CP stars in general. In addition, CP characteristics seem to be individual properties not repeated in a component star or other cluster members. (author). 50 refs., 5 tabs., 3 figs

  14. 1-3 Nuclear In-medium Effects of Strange Particles in Proton-nucleus Collisions

    Institute of Scientific and Technical Information of China (English)

    Feng; Zhaoqing[1

    2014-01-01

    Extraction of the in-medium properties of strange particles from heavy-ion collisions is very complicated, since he nuclear density varies in the evolution of nucleus-nucleus collisions. To avoid the uncertainties of the baryon ensities during the stage of strange particle production, one can investigate proton-nucleus collisions where the uclear density is definite around the saturation density. Dynamics of strange particles produced in the protoninduced uclear the reactions near the threshold energies has been investigated within the Lanzhou quantum olecular dynamics (LQMD) transport model. The in-medium modifications on particle production in densenuclear matter are considered through the corrections to the elementary cross sections via the effective mass and he mean-field potentials[1].

  15. Low-lying 1/2- hidden strange pentaquark states in the constituent quark model

    Science.gov (United States)

    Li, Hui; Wu, Zong-Xiu; An, Chun-Sheng; Chen, Hong

    2017-12-01

    We investigate the spectrum of the low-lying 1/2- hidden strange pentaquark states, employing the constituent quark model, and looking at two ways within that model of mediating the hyperfine interaction between quarks - Goldstone boson exchange and one gluon exchange. Numerical results show that the lowest 1/2- hidden strange pentaquark state in the Goldstone boson exchange model lies at ˜1570 MeV, so this pentaquark configuration may form a notable component in S 11(1535) if the Goldstone boson exchange model is applied. This is consistent with the prediction that S 11(1535) couples very strongly to strangeness channels. Supported by National Natural Science Foundation of China (11675131, 11645002), Chongqing Natural Science Foundation (cstc2015jcyjA00032) and Fundamental Research Funds for the Central Universities (SWU115020)

  16. Fast reconstruction of multi-strange hyperons in the CBM experiment

    Energy Technology Data Exchange (ETDEWEB)

    Vassiliev, Iouri [GSI, Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Collaboration: CBM-Collaboration

    2015-07-01

    The main goal of the CBM experiment is to study the behaviour of nuclear matter at very high baryonic density in which the transition to a deconfined and chirally restored phase is expected to happen. One of the promissing signatures of this new state is the enhanced production of multi-strange particles, therefore the reconstruction of multi-strange hyperons is essential for the understanding of the heavy ion collision dynamics. Another experimental challenge of the CBM experiment is online selection of open charm particles via the displaced vertex of the hadronic decay, Charmonium and low mass vector mesons in the environment of a heavy-ion collision. This task requires fast and efficient track reconstruction algorithms, primary vertex finder and particles finder. Results of feasibility studies of the multi-strange hyperons in the CBM experiment are presented.

  17. Ratios of strange hadrons to pions in collisions of large and small nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Oeschler, H. [Ruprecht-Karls-Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Cleymans, J. [University of Cape Town, UCT-CERN Research Centre and Department of Physics, Rondebosch (South Africa); Hippolyte, B. [Universite de Strasbourg, CNRS-IN2P3, Institut Pluridisciplinaire Hubert Curien (IPHC), Strasbourg (France); Redlich, K. [University of Wroclaw, Institute of Theoretical Physics, Wroclaw (Poland); ExtreMe Matter Institute EMMI, GSI, Darmstadt (Germany); Sharma, N. [Panjab University, Department of Physics, Chandigarh (India)

    2017-09-15

    The dependence of particle production on the size of the colliding nuclei is analyzed in terms of the thermal model using the canonical ensemble. The concept of strangeness correlation in clusters of sub-volume V{sub c} is used to account for the suppression of strangeness. A systematic analysis is presented of the predictions of the thermal model for particle production in collisions of small nuclei. The pattern of the maxima of strange-particles-to-pion ratios as a function of beam energy is quite special, as they do not occur at the same beam energy and are sensitive to the system size. In particular, the Λ/π{sup +} ratio shows a clear maximum even for small systems while the maximum in the K{sup +}/π{sup +} ratio is less pronounced in small systems. (orig.)

  18. Beauty-conserving strangeness-changing rare semileptonic decays of Bs meson

    International Nuclear Information System (INIS)

    Harpreet Kaur

    1999-01-01

    The beauty-conserving strangeness-changing decays of B s meson are examined. In the charm sector, charm-conserving strangeness changing (Δc = 0, Δs ≠ 0) decays are Cabibbo suppressed and are governed by the CKM element V us which is much smaller than the CKM diagonal element V cs , so may be of little interest. On the other hand, in the b-sector, beauty-conserving strangeness changing (Δb = 0, Δs ≠ 0) decays are CKM allowed as the CKM matrix element V us governing such decays is much larger than V bc or V bu which govern respectively the b→c or b→u transitions. The phase space available, however, is too small for the decays considered here. The numerical estimates for the decay widths of two such modes of B s meson are presented. (author)

  19. Measuring the strangeness content of the nucleon by observing the ϕ-meson mass shift in nuclear matter

    International Nuclear Information System (INIS)

    Gubler, Philipp; Ohtani, Keisuke

    2015-01-01

    The modification of the ϕ-meson at finite density is studied by using QCD sum rules in combination with the maximum entropy method. As a result, it is found that the mass shift of the ϕ-meson is strongly correlated to the strangeness content of the nucleon, , which governs the depletion of the strange quark condensate in nuclear matter. (author)

  20. Neutral strange particle production at top SPS energy measured by the CERES experiment

    International Nuclear Information System (INIS)

    Radomski, S.

    2006-01-01

    Systematics of strange particle production in collisions of ultrarelativistic nuclei provides an insight into the properties of the strongly interacting matter. Hadrochemistry, the study of the relative yields, provides information about chemical freeze-out and the position of the system in the phase diagram. Strangeness production at Super Proton Synchrotron (SPS) energies is not fully explained by the thermal model of hadron gas. Data reported by one experiment show sharp structures as a function of energy which are interpreted as a signature for a phase transition, but due to discrepancies in the results between two different experiments, a conclusion can not be drawn. This thesis is part of an effort to build a database of the strangeness production at SPS energy. The particular subject of this work is a precise measurement of the production of K S 0 . The results are compared with two other experiments and the prediction of the thermal model. The high precision data shed light on the systematics of strangeness production and allow clarification of the experimental status. The study of transverse momentum spectra provides information about the temperature and the radial expansion of the system. Here, as in the case of particle yields, interesting structures are visible as a function of energy. A rapid increase in the number of degrees of freedom is visible in the SPS region. A large part of the strangeness is carried by the neutral strange baryon Λ. Here the experimental situation is even more complicated because the reconstruction of the Λ yield requires large extrapolation to low transverse momentum. In this work first results on Λ production will be presented. (orig.)

  1. Neutral strange particle production at top SPS energy measured by the CERES experiment

    Energy Technology Data Exchange (ETDEWEB)

    Radomski, S.

    2006-07-05

    Systematics of strange particle production in collisions of ultrarelativistic nuclei provides an insight into the properties of the strongly interacting matter. Hadrochemistry, the study of the relative yields, provides information about chemical freeze-out and the position of the system in the phase diagram. Strangeness production at Super Proton Synchrotron (SPS) energies is not fully explained by the thermal model of hadron gas. Data reported by one experiment show sharp structures as a function of energy which are interpreted as a signature for a phase transition, but due to discrepancies in the results between two different experiments, a conclusion can not be drawn. This thesis is part of an effort to build a database of the strangeness production at SPS energy. The particular subject of this work is a precise measurement of the production of K{sub S}{sup 0}. The results are compared with two other experiments and the prediction of the thermal model. The high precision data shed light on the systematics of strangeness production and allow clarification of the experimental status. The study of transverse momentum spectra provides information about the temperature and the radial expansion of the system. Here, as in the case of particle yields, interesting structures are visible as a function of energy. A rapid increase in the number of degrees of freedom is visible in the SPS region. A large part of the strangeness is carried by the neutral strange baryon {lambda}. Here the experimental situation is even more complicated because the reconstruction of the {lambda} yield requires large extrapolation to low transverse momentum. In this work first results on {lambda} production will be presented. (orig.)

  2. Rates of star formation

    International Nuclear Information System (INIS)

    Larson, R.B.

    1977-01-01

    It is illustrated that a theoretical understanding of the formation and evolution of galaxies depends on an understanding of star formation, and especially of the factors influencing the rate of star formation. Some of the theoretical problems of star formation in galaxies, some approaches that have been considered in models of galaxy evolution, and some possible observational tests that may help to clarify which processes or models are most relevant are reviewed. The material is presented under the following headings: power-law models for star formation, star formation processes (conditions required, ways of achieving these conditions), observational indications and tests, and measures of star formation rates in galaxies. 49 references

  3. Energy production in stars

    International Nuclear Information System (INIS)

    Bethe, Hans.

    1977-01-01

    Energy in stars is released partly by gravitation, partly by nuclear reactions. For ordinary stars like our sun, nuclear reactions predominate. However, at the end of the life of a star very large amounts of energy are released by gravitational collapse; this can amount to as much as 10 times the total energy released nuclear reactions. The rotational energy of pulsars is a small remnant of the energy of gravitation. The end stage of small stars is generally a white dwarf, of heavy stars a neutron star of possibly a black hole

  4. STAR FORMATION IN 30 DORADUS

    International Nuclear Information System (INIS)

    De Marchi, Guido; Spezzi, Loredana; Sirianni, Marco; Andersen, Morten; Paresce, Francesco; Panagia, Nino; Mutchler, Max; Whitmore, Bradley C.; Bond, Howard; Beccari, Giacomo; Balick, Bruce; Dopita, Michael A.; Frogel, Jay A.; Calzetti, Daniela; Marcella Carollo, C.; Disney, Michael J.; Hall, Donald N. B.; Holtzman, Jon A.; Kimble, Randy A.; McCarthy, Patrick J.

    2011-01-01

    Using observations obtained with the Wide-Field Camera 3 on board the Hubble Space Telescope, we have studied the properties of the stellar populations in the central regions of 30 Dor in the Large Magellanic Cloud. The observations clearly reveal the presence of considerable differential extinction across the field. We characterize and quantify this effect using young massive main-sequence stars to derive a statistical reddening correction for most objects in the field. We then search for pre-main-sequence (PMS) stars by looking for objects with a strong (>4σ) Hα excess emission and find about 1150 of them over the entire field. Comparison of their location in the Hertzsprung-Russell diagram with theoretical PMS evolutionary tracks for the appropriate metallicity reveals that about one-third of these objects are younger than ∼4 Myr, compatible with the age of the massive stars in the central ionizing cluster R 136, whereas the rest have ages up to ∼30 Myr, with a median age of ∼12 Myr. This indicates that star formation has proceeded over an extended period of time, although we cannot discriminate between an extended episode and a series of short and frequent bursts that are not resolved in time. While the younger PMS population preferentially occupies the central regions of the cluster, older PMS objects are more uniformly distributed across the field and are remarkably few at the very center of the cluster. We attribute this latter effect to photo-evaporation of the older circumstellar disks caused by the massive ionizing members of R 136.

  5. Regular Generalized Star Star closed sets in Bitopological Spaces

    OpenAIRE

    K. Kannan; D. Narasimhan; K. Chandrasekhara Rao; R. Ravikumar

    2011-01-01

    The aim of this paper is to introduce the concepts of τ1τ2-regular generalized star star closed sets , τ1τ2-regular generalized star star open sets and study their basic properties in bitopological spaces.

  6. Strange particles: production by Cosmotron beams as observed in diffusion cloud chambers

    International Nuclear Information System (INIS)

    Fowler, W.B.

    1989-01-01

    Proton beams, from the 1GeV Cosmotron accelerator at Brookhaven, were used in the 1950s to produce strange particles. One big leap forward technologically was the development of the diffusion cloud chamber which made detecting particle tracks more accurate and sensitive. A large co-operative team worked on its development. By the mid 1950s enough tracks had been observed to show the associated production of strange particles. It was the same Brookhaven workers who developed the eighty-inch hydrogen bubble chamber which took the first photograph of the long predicted omega minus particle at the end of the decade. (UK)

  7. Rank One Strange Attractors in Periodically Kicked Predator-Prey System with Time-Delay

    Science.gov (United States)

    Yang, Wenjie; Lin, Yiping; Dai, Yunxian; Zhao, Huitao

    2016-06-01

    This paper is devoted to the study of the problem of rank one strange attractor in a periodically kicked predator-prey system with time-delay. Our discussion is based on the theory of rank one maps formulated by Wang and Young. Firstly, we develop the rank one chaotic theory to delayed systems. It is shown that strange attractors occur when the delayed system undergoes a Hopf bifurcation and encounters an external periodic force. Then we use the theory to the periodically kicked predator-prey system with delay, deriving the conditions for Hopf bifurcation and rank one chaos along with the results of numerical simulations.

  8. Strangeness production in proton and heavy ion collisions at 200 A GeV

    International Nuclear Information System (INIS)

    Amelin, N.S.; Bravina, L.V.; Csernai, L.P.; Toneev, V.D.; Gudima, K.K.; Sivoklokov, S.Y.

    1992-11-01

    Strangeness production at SPS-CERN energies is studied within the Quark Gluon String Model. The observed shape of rapidity and transverse mass distributions are reproduced fairly well for both peripheral and central heavy ion collisions. However, for central collisions the model underpredicts strange particle abundances by a factor of about 2:2:4 for K S 0 , Λ and antiΛ, respectively. This discrepancy can be considered as a possible manifestation of collective string-string interactions similar to the formation of a color rope. Model predictions for coming experiments with the Pb beam at CERN are given. 30 refs. 11 figs., 3 tabs

  9. Nuclear corrections in neutrino deep inelastic scattering and the extraction of the strange quark distribution

    International Nuclear Information System (INIS)

    Boros, C.

    1999-01-01

    Recent measurement of the structure function F 2 υ in neutrino deep inelastic scattering allows us to compare structure functions measured in neutrino and charged lepton scattering for the first time with reasonable precision. The comparison between neutrino and muon structure functions made by the CCFR Collaboration indicates that there is a discrepancy between these structure functions at small Bjorken x values. In this talk I examine two effects which might account for this experimental discrepancy: nuclear shadowing corrections for neutrinos and contributions from strange and anti-strange quarks. Copyright (1999) World Scientific Publishing Co. Pte. Ltd

  10. Strange quark condensate in the nucleon in 2 + 1 flavor QCD.

    Science.gov (United States)

    Toussaint, D; Freeman, W

    2009-09-18

    We calculate the "strange quark content of the nucleon," , which is important for interpreting the results of some dark matter detection experiments. The method is to evaluate quark-line disconnected correlations on the MILC lattice ensembles, which include the effects of dynamical light and strange quarks. After continuum and chiral extrapolations, the result is = 0.69(7)_{stat}(9)_{syst}, in the modified minimal subtraction scheme (2 GeV) regularization, or for the renormalization scheme invariant form, m_{s} partial differentialM_{N}/ partial differentialm_{s} = 59(6)(8) MeV.

  11. Parity Violation in Elastic Electron-Proton Scattering and the Proton's Strange Magnetic Form Factor

    International Nuclear Information System (INIS)

    Spayde, D. T.; Averett, T.; Barkhuff, D.; Beck, D. H.; Beise, E. J.; Benson, C.; Breuer, H.; Carr, R.; Covrig, S.; DelCorso, J.

    2000-01-01

    We report a new measurement of the parity-violating asymmetry in elastic electron scattering from the proton at backward scattering angles. This asymmetry is sensitive to the strange magnetic form factor of the proton as well as electroweak axial radiative corrections. The new measurement of A=-4.92±0.61±0.73 ppm provides a significant constraint on these quantities. The implications for the strange magnetic form factor are discussed in the context of theoretical estimates for the axial corrections. (c) 2000 The American Physical Society

  12. Neutral strange particle production in antineutrino-neon charged current interactions

    Science.gov (United States)

    Willocq, S.; Marage, P.; Aderholz, M.; Allport, P.; Baton, J. P.; Berggren, M.; Clayton, E. F.; Cooper-Sarkar, A. M.; Erriquez, O.; Faulkner, P. J. W.; Guy, J.; Hulth, P. O.; Jones, G. T.; Mobayyen, M. M.; Morrison, D. R. O.; Neveu, M.; O'Neale, S.; Sacton, J.; Sansum, R. A.; Varvell, K.; Venus, W.; Wells, J.; Wittek, W.

    1992-06-01

    Neutral strange particle production inbar v Ne charged current interactions is studied using the bubble chamber BEBC, exposed to the CERN SPS antineutrino wide band beam. From a sample of 1191 neutral strange particles, the inclusive production rates are determined to be (15.7±0.8)% for K 0 mesons, (8.2±0.5)% for Λ, (0.4±0.2)% forbar Λ and (0.6±0.3)% for Σ0 hyperons. The inclusive production properties of K 0 mesons and Λ hyperons are investigated. The Λ hyperons are found to be polarized in the production plane.

  13. ENERGY STAR Certified Displays

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 7.0 ENERGY STAR Program Requirements for Displays that are effective as of July 1, 2016....

  14. ENERGY STAR Certified Boilers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 3.0 ENERGY STAR Program Requirements for Boilers that are effective as of October 1,...

  15. ENERGY STAR Certified Televisions

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 7.0 ENERGY STAR Program Requirements for Televisions that are effective as of October 30,...

  16. ENERGY STAR Certified Dehumidifiers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 4.0 ENERGY STAR Program Requirements for Dehumidifiers that are effective as of October...

  17. Observations of central stars

    International Nuclear Information System (INIS)

    Lutz, J.H.

    1978-01-01

    Difficulties occurring in the observation of central stars of planetary nebulae are reviewed with emphasis on spectral classifications and population types, and temperature determination. Binary and peculiar central stars are discussed. (U.M.G.)

  18. ENERGY STAR Certified Telephones

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 3.0 ENERGY STAR Program Requirements for Telephony (cordless telephones and VoIP...

  19. Wolf-Rayet stars

    Energy Technology Data Exchange (ETDEWEB)

    Sahade, J

    1981-12-01

    Aspects of the problems of the Wolf-Rayet stars related to their chemical composition, their evolutionary status, and their apparent dichotomy in two spectral sequences are discussed. Dogmas concerning WR stars are critically discussed, including the belief that WR stars lack hydrogen, that they are helium stars evolved from massive close binaries, and the existence of a second WR stage in which the star is a short-period single-lined binary. The relationship of WR stars with planetary nebulae is addressed, as is the membership of these stars in clusters and associations. The division of WR stars into WN and WC sequences is considered, questioning the reasonability of accounting for WR line formation in terms of abundance differences.

  20. Star formation: Cosmic feast

    Science.gov (United States)

    Scaringi, Simone

    2017-03-01

    Low-mass stars form through a process known as disk accretion, eating up material that orbits in a disk around them. It turns out that the same mechanism also describes the formation of more massive stars.

  1. Nucleation of Quark Matter in Neutron Stars:. Role of Color Superconductivity

    Science.gov (United States)

    Bombaci, Ignazio; Lugones, Germán; Vidaña, Isaac

    2008-02-01

    Pure hadronic compact stars ("neutron stars") above a critical mass Mcr are metastable1,2 for the conversion to quark stars (hybrid or strange stars). This conversion process liberates an enormous amount of energy (Econv ~ 1053 ergs), which could power some of the observed gamma ray bursts.1-3 In cold deleptonized hadronic stars, the conversion process is triggered by the quantum nucleation of a quark matter drop in the stellar center. These drops can be made up of normal (i.e. unpaired) quark matter, or color superconducting quark matter, depending on the details of the equation of state of quark and hadronic matter.4 In this talk, we present the results of recent calculations5 of the effects of color superconductivity on the conversion of hadronic stars to quark stars. In particular, we study the dependence of the critical mass Mcr and conversion energy Econv on the quark-quark pairing gap Δ, the bag constant B, and the surface tension σ of the quark-hadron interface.

  2. Autonomous Star Tracker Algorithms

    DEFF Research Database (Denmark)

    Betto, Maurizio; Jørgensen, John Leif; Kilsgaard, Søren

    1998-01-01

    Proposal, in response to an ESA R.f.P., to design algorithms for autonomous star tracker operations.The proposal also included the development of a star tracker breadboard to test the algorithms performances.......Proposal, in response to an ESA R.f.P., to design algorithms for autonomous star tracker operations.The proposal also included the development of a star tracker breadboard to test the algorithms performances....

  3. Set discrimination of quantum states

    International Nuclear Information System (INIS)

    Zhang Shengyu; Ying Mingsheng

    2002-01-01

    We introduce a notion of set discrimination, which is an interesting extension of quantum state discrimination. A state is secretly chosen from a number of quantum states, which are partitioned into some disjoint sets. A set discrimination is required to identify which set the given state belongs to. Several essential problems are addressed in this paper, including the condition of perfect set discrimination, unambiguous set discrimination, and in the latter case, the efficiency of the discrimination. This generalizes some important results on quantum state discrimination in the literature. A combination of state and set discrimination and the efficiency are also studied

  4. The Optical/UV Excess of X-Ray-dim Isolated Neutron Stars. I. Bremsstrahlung Emission from a Strangeon Star Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Weiyang; Lu, Jiguang; Men, Yunpeng; Xu, Renxin [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Tong, Hao [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi 830011 (China); Ge, Mingyu [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Li, Zhaosheng, E-mail: r.x.xu@pku.edu.cn [Department of Physics, Xiangtan University, Xiangtan 411105 (China)

    2017-03-01

    X-ray-dim isolated neutron stars (XDINSs) are characterized by Planckian spectra in X-ray bands, but show optical/ultraviolet (UV) excesses: the factors by which the measured photometry exceeds those extrapolated from X-ray spectra. To solve this problem, a radiative model of bremsstrahlung emission from a plasma atmosphere is established in the regime of a strangeon star. A strangeon star atmosphere could simply be regarded as the upper layer of a normal neutron star. This plasma atmosphere, formed and maintained by the interstellar-medium-accreted matter due to the so-called strangeness barrier, is supposed to be of two temperatures. All seven XDINS spectra could be well fitted by the radiative model, from optical/UV to X-ray bands. The fitted radiation radii of XDINSs are from 7 to 13 km, while the modeled electron temperatures are between 50 and 250 eV, except RX J0806.4–4123, with a radiation radius of ∼3.5 km, indicating that this source could be a low-mass strangeon star candidate. This strangeon star model could further be tested by soft X-ray polarimetry, such as the Lightweight Asymmetry and Magnetism Probe, which is expected to be operational on China’s space station around 2020.

  5. Neuronal discrimination capacity

    International Nuclear Information System (INIS)

    Deng Yingchun; Williams, Peter; Feng Jianfeng; Liu Feng

    2003-01-01

    We explore neuronal mechanisms of discriminating between masked signals. It is found that when the correlation between input signals is zero, the output signals are separable if and only if input signals are separable. With positively (negatively) correlated signals, the output signals are separable (mixed) even when input signals are mixed (separable). Exact values of discrimination capacity are obtained for two most interesting cases: the exactly balanced inhibitory and excitatory input case and the uncorrelated input case. Interestingly, the discrimination capacity obtained in these cases is independent of model parameters, input distribution and is universal. Our results also suggest a functional role of inhibitory inputs and correlated inputs or, more generally, the large variability of efferent spike trains observed in in vivo experiments: the larger the variability of efferent spike trains, the easier it is to discriminate between masked input signals

  6. Neuronal discrimination capacity

    Energy Technology Data Exchange (ETDEWEB)

    Deng Yingchun [Department of Mathematics, Hunan Normal University 410081, Changsha (China); COGS, University of Sussex at Brighton, BN1 9QH (United Kingdom); Williams, Peter; Feng Jianfeng [COGS, University of Sussex at Brighton, BN1 9QH (United Kingdom); Liu Feng [COGS, University of Sussex at Brighton, BN1 9QH (United Kingdom); Physics Department, Nanjing University (China)

    2003-12-19

    We explore neuronal mechanisms of discriminating between masked signals. It is found that when the correlation between input signals is zero, the output signals are separable if and only if input signals are separable. With positively (negatively) correlated signals, the output signals are separable (mixed) even when input signals are mixed (separable). Exact values of discrimination capacity are obtained for two most interesting cases: the exactly balanced inhibitory and excitatory input case and the uncorrelated input case. Interestingly, the discrimination capacity obtained in these cases is independent of model parameters, input distribution and is universal. Our results also suggest a functional role of inhibitory inputs and correlated inputs or, more generally, the large variability of efferent spike trains observed in in vivo experiments: the larger the variability of efferent spike trains, the easier it is to discriminate between masked input signals.

  7. Covering tree with stars

    DEFF Research Database (Denmark)

    Baumbach, Jan; Guo, Jian-Ying; Ibragimov, Rashid

    2013-01-01

    We study the tree edit distance problem with edge deletions and edge insertions as edit operations. We reformulate a special case of this problem as Covering Tree with Stars (CTS): given a tree T and a set of stars, can we connect the stars in by adding edges between them such that the resulting ...

  8. America's Star Libraries

    Science.gov (United States)

    Lyons, Ray; Lance, Keith Curry

    2009-01-01

    "Library Journal"'s new national rating of public libraries, the "LJ" Index of Public Library Service, identifies 256 "star" libraries. It rates 7,115 public libraries. The top libraries in each group get five, four, or three Michelin guide-like stars. All included libraries, stars or not, can use their scores to learn from their peers and improve…

  9. Discrimination in Textbooks

    OpenAIRE

    大津, 尚志

    1996-01-01

    In this paper, I deal with the issues which concern discriminations in textbooks.In America, they have paid special attentions to these problems since 1960's. They made guidelines for textbooks to check various kinds of discriminative descriptions and tried to make textbooks to meet these standards. In this respects I would examine the present states about textbooks in America and would compare them to the Japanese ones. That would be useful, I believe, when we consider these issues in Japan.

  10. Breakdown of I-Love-Q Universality in Rapidly Rotating Relativistic Stars

    Science.gov (United States)

    Doneva, Daniela D.; Yazadjiev, Stoytcho S.; Stergioulas, Nikolaos; Kokkotas, Kostas D.

    2014-01-01

    It was shown recently that normalized relations between the moment of inertia (I), the quadrupole moment (Q), and the tidal deformability (Love number) exist and for slowly rotating neutron stars they are almost independent of the equation of state (EOS). We extend the computation of the I-Q relation to models rotating up to the mass-shedding limit and show that the universality of the relations is lost. With increasing rotation rate, the normalized I-Q relation departs significantly from its slow-rotation limit, deviating up to 40% for neutron stars and up to 75% for strange stars. The deviation is also EOS dependent and for a broad set of hadronic and strange matter EOSs the spread due to rotation is comparable to the spread due to the EOS, if one considers sequences with fixed rotational frequency. Still, for a restricted sample of modern realistic EOSs one can parameterize the deviations from universality as a function of rotation only. The previously proposed I-Love-Q relations should thus be used with care, because they lose their universality in astrophysical situations involving compact objects rotating faster than a few hundred Hz.

  11. BREAKDOWN OF I-LOVE-Q UNIVERSALITY IN RAPIDLY ROTATING RELATIVISTIC STARS

    International Nuclear Information System (INIS)

    Doneva, Daniela D.; Yazadjiev, Stoytcho S.; Kokkotas, Kostas D.; Stergioulas, Nikolaos

    2014-01-01

    It was shown recently that normalized relations between the moment of inertia (I), the quadrupole moment (Q), and the tidal deformability (Love number) exist and for slowly rotating neutron stars they are almost independent of the equation of state (EOS). We extend the computation of the I-Q relation to models rotating up to the mass-shedding limit and show that the universality of the relations is lost. With increasing rotation rate, the normalized I-Q relation departs significantly from its slow-rotation limit, deviating up to 40% for neutron stars and up to 75% for strange stars. The deviation is also EOS dependent and for a broad set of hadronic and strange matter EOSs the spread due to rotation is comparable to the spread due to the EOS, if one considers sequences with fixed rotational frequency. Still, for a restricted sample of modern realistic EOSs one can parameterize the deviations from universality as a function of rotation only. The previously proposed I-Love-Q relations should thus be used with care, because they lose their universality in astrophysical situations involving compact objects rotating faster than a few hundred Hz

  12. Making the Familiar Strange: Creative Cultural Storytelling within the Communication Classroom

    Science.gov (United States)

    Blinne, Kristen C.

    2012-01-01

    In this activity, students employ mock campfire storytelling to "make the familiar strange" in the same spirit as Horace Miner's (1956) classic tale of the "Nacirema." Students work individually, in pairs, or as small groups (around three) to create a whimsical story that deconstructs a mundane, everyday ritual (event, activity, practice) into a…

  13. Measurement of the strange quark contribution to the proton spin using neutral kaons at HERMES

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Shaojun

    2007-03-15

    This thesis reports a new ''isoscalar'' measurement of {delta}s + {delta} anti s. Because strange quarks carry no isospin, the strange seas in the proton and neutron are identical. In the deuteron, an isoscalar target, the fragmentation process in DIS can be described without any assumptions regarding isospin dependent fragmentation. In the isoscalar extraction of {delta}s + {delta} anti s only the spin asymmetry for K{sup 0}{sub s} A{sup K{sup 0}{sub s1,d}} (x,Q{sup 2}, z) and the inclusive asymmetry A{sub 1,d}(x,Q{sup 2}) are used. An accurate measurement of the total non-strange quark polarisation {delta}Q = {delta}u + {delta} anti u + {delta}d + {delta} anti d comes directly from A{sub 1,d}(x,Q{sup 2}). The fragmentation functions needed for a leading order (LO) extraction of {delta}S = {delta}s + {delta} anti s are measured directly at HERMES kinematics using the same data. As a result of this analysis, the helicity densities for the strange quarks are consistent with zero with the experimental uncertainty over the measured x kinematic range. (orig.)

  14. [Search for strange quark matter and antimatter produced in high energy heavy ion collisions

    International Nuclear Information System (INIS)

    1992-01-01

    This document describes the development and progress of our group's research program in high energy heavy ion physics. We are a subset of the Yale experimental high energy physics effort (YAUG group) who became interested in the physics of high energy heavy ions in 1988. Our interest began with the possibility of performing significant searches for strange quark matter. As we learned more about the subject and as we gained experimental experience through our participation in AGS experiment 814, our interests have broadened. Our program has focused on the study of new particles, including (but not exclusively) strange quark matter, and the high sensitivity measurement of other composite nuclear systems such as antinuclei and various light nuclei. The importance of measurements of the known, but rare, nuclear systems lies in the study of production mechanisms. A good understanding of the physics and phenomenology of rare composite particle production in essential for the interpretation of limits to strange quark matter searches. We believe that such studies will also be useful in probing the mechanisms involved in the collision process itself. We have been involved in the running and data analysis for AGS E814. We have also worked on the R ampersand D for AGS E864, which is an approved experiment designed to reach sensitivities where there will be a good chance of discovering strangelets or of setting significant limits on the parameters of strange quark matter

  15. Polarization observables for strangeness photoproduction on a frozen spin target with CLAS at Jefferson Lab

    International Nuclear Information System (INIS)

    Fegan, Stuart

    2012-01-01

    The FROST experiment at Jefferson Lab used the CLAS detector in Hall B with the intention of performing a complete measurement of polarization observables associated with strangeness photoproduction, in combination with data from previous JLab experiments. This was achieved by utilizing the FROST polarized target in conjunction with polarized photon beams, allowing direct measurement of beam-target double polarization observables. By studying strangeness reactions, such as γp → K + Λ 0 , it may be possible to find 'missing' baryon resonances, predicted by symmetric quark models but not observed in previous experiments, whose results are consistent with the di-quark model. It is thought these 'missing' resonances remain undiscovered because they have different coupling strengths for different reaction channels, such as the strangeness reactions, whereas the current data is dominated by studies of pN reactions. Observing these resonances therefore has important implications for our knowledge of the excited states of nucleons, and the models predicting the quark interactions within them. The G polarization observable is one of the beam-target double polarization observables, associated with a longitudinally polarized target and a linearly polarized photon beam, and its measurement for the strangeness reaction γp → K + Λ 0 is the focus of the work presented.

  16. Cross-Cultural Patterns of Attachment: A Meta-Analysis of t?Y Strange Situation.

    Science.gov (United States)

    van IJzendoorn, Marinus H.; Kroonenberg, Pieter M.

    1988-01-01

    Examines 2,000 Strange Situation classifications obtained in eight different countries. Differences and similarities between distributions in classifications of samples are investigated using correspondence analysis. Substantial intracultural differences are established; data also suggest a pattern of cross-cultural differences. (Author/RWB)

  17. Are We Losing the Next Generation? A Strange Experience on a Poetry Course.

    Science.gov (United States)

    Holbrook, David

    1981-01-01

    Examining the attitudes and behaviors of his adolescent students in rural Yorkshire, the author finds in them a strange lack of respect for adults, which he attributes to disruptions of consciousness caused by the constant bombardment of pop music and television. Two other authors comment on pp128-30. (SJL)

  18. Comparing phenomenological recipes with a microscopic model for the electric amplitude in strangeness photoproduction

    NARCIS (Netherlands)

    Korchin, AY; Scholten, O

    2003-01-01

    Corrections to the Born approximation in photoinduced strangeness production off a proton are calculated in a semirealistic microscopic model. The vertex corrections and internal contributions to the amplitude of the gammap-->K+Lambda reaction are included on the one-loop level. Different

  19. Strangeness S = -2 baryon-baryon interactions using chiral effective field theory

    NARCIS (Netherlands)

    Polinder, H.; Haidenbauer, J.; Meissner, U.G.

    2007-01-01

    We derive the leading order strangeness S =−2 baryon–baryon interactions in chiral effective field theory. The potential consists of contact terms without derivatives and of one-pseudoscalar-meson exchanges. The contact terms and the couplings of the pseudoscalar mesons to the baryons are related

  20. Sigma Terms and Strangeness Contents of Baryon Octet in Modified Chiral Perturbation Theory

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-Ya; L(U) Xiao-Fu

    2006-01-01

    In the frame work of chiral perturbation theory, a modified effective Lagrangian for meson-baryon system is constructed, where the SU(3) breaking effect for meson is considered. The difference between physical and chiral limit decay constants is taken into account. Calculated to one loop at O(p3), the sigma terms and strangeness contents of baryon octet are obtained.