Solid Bare Strange Quark Stars
Xu, R X
2003-01-01
The reason, we need three terms of `strange', `bare', and `solid' before quark stars, is presented concisely though some fundamental issues are not certain. Observations favoring these stars are introduced.
Magnetospheric activity of bare strange quark stars
Yu, J. W.; Xu, R. X.
2011-06-01
In the model of Ruderman and Sutherland, the binding energy problem is a severe problem when modelling normal neutron stars as pulsars, i.e. both ions (e.g. 5626Fe) and electrons on the normal neutron star surface can be pulled out freely by the unipolar generator induced electric field, so that sparking on the polar cap can hardly occur. This problem can be solved within the partially screened gap (PSG) model for neutron stars. However, in this paper, we study this problem extensively in a model of bare strange quark stars (BSSs). We find that the huge potential barrier built by the electric field in the vacuum gap above the polar cap can usually prevent electrons from streaming into the magnetosphere, unless the electric potential of a pulsar is sufficiently lower than that at the infinite interstellar medium. Other processes, such as the diffusion and thermionic emission of electrons, have also been included here. Our conclusions are as follows. Both positive and negative particles on the surface of a BSS are bound strongly enough to form a vacuum gap above its polar cap as long as the BSS is not charged (or not highly negative charged), and multi-accelerators can occur in the magnetosphere of the BSS. Our results may be helpful to distinguish normal neutron stars and bare quark stars using a pulsar's magnetospheric activities.
A TFD model for the Electrospheres of Bare Strange Quark Stars
Guo, Hai-Chuan; Zhang, Cheng-Min
2007-01-01
We study the layer of electrons on bare strange star surfaces, taking the Dirac exchange-energy into account. Because electrons are fermions, the electron wave function must be of exchange-antisymmetry. The Dirac exchange-energy originates, consequently, from the exchange-antisymmetry of electron wave functions. This consideration may result in changing the electron distribution and the electric field on the surface of bare strange star. The strong magnetic field effect on the structures of the electrospheres is also discussed.
Thermal Photons From Magnetized Bare Strange Stars
Méndez, Enrique Moreno; Patiño, Leonardo; Ortega, Patricia
2013-01-01
A plasma made out of strange-quark matter (SQM) and electrons, has a rather high plasma frequency (>20 MeV). Thus, a compact star made of such material all the way up to its surface, i.e., a bare strange star, would be unable to radiate away its thermal emission. We use the MIT-bag model and assume that SQM is the ground state of nuclear matter at high density. We investigate whether the presence of a magnetic field will allow propagation of radiation at frequencies below the SQM plasma frequencies. Hence, we study the presence of gyrofrequencies in a SQM plasma permeated by a strong magnetic field (B > 10^{12} G). We find that small regions in the frequency spectrum allow radiation propagation due to the presence of the magnetic fields. It is likely that narrow bands of radiation would likely be observable from magnetized bare strange stars .
International Nuclear Information System (INIS)
We investigate the properties of multi-strange baryonic systems, comparing conventional many -- Λ hypernuclei, where the strange quarks are localized in individual hyperons, to ''strangelets'' or chunks of strange matter, which involves delocalized quarks which roam in a single large bag. Mass formulae and strong/weak decay modes for such objects are discussed, as well as the prospects for producing multi-strange systems in relativistic heavy ion collisions. For production, we consider two extremes, one based on the coalescence model and another which assumes the formation of quark-gluon-plasma. We mention the experimental searches which are underway or planned, using heavy ion beams
Surface photon emissivity of bare strange stars
Cheng, KS; Harko, T.
2003-01-01
We consider the bremsstrahlung surface photon emissivity of strange quark stars, by systematically taking into account the effects of the multiple scatterings of highly relativistic quarks in a dense medium (the Landau-Pomeranchuk-Migdal effect). Because of interference between amplitudes of nearby interactions, the bremsstrahlung emissivity from a strange star surface is suppressed for frequencies smaller than a critical frequency. The range of the suppressed frequencies is a function of the...
Search for strange quark matter
Hill, J C
2000-01-01
We present results of a search for charged and neutral strangelets produced on collisions of 11.6 A GeV/c Au beams with Pt or Pb targets. Yields of light nuclei and hypernuclei produced by coalescence were measured. Penalty factors were measured for the addition to a fragment of a nucleon or strange hadron. These are useful in planning future searches for strange quark matter.
Space-Time Geometry of Quark and Strange Quark Matter
Institute of Scientific and Technical Information of China (English)
无
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).
Metastable strange matter and compact quark stars
Malheiro, M; Taurines, A R
2003-01-01
Strange quark matter in beta equilibrium at high densities is studied in a quark confinement model. Two equations of state are dynamically generated for the {\\it same} set of model parameters used to describe the nucleon: one corresponds to a chiral restored phase with almost massless quarks and the other to a chiral broken phase. The chiral symmetric phase saturates at around five times the nuclear matter density. Using the equation of state for this phase, compact bare quark stars are obtained with radii and masses in the ranges $R\\sim 5 - 8$ km and $M\\sim M_\\odot$. The energy per baryon number decreases very slowly from the center of the star to the periphery, remaining above the corresponding values for the iron or the nuclear matter, even at the edge. Our results point out that strange quark matter at very high densities may not be absolutely stable and the existence of an energy barrier between the two phases may prevent the compact quarks stars to decay to hybrid stars.
On the strange quark mass with improved staggered quarks
Hein, J.; Davies, C; Lepage, G. P.; Mason, Q.; Trottier, H.
2002-01-01
We present results on the sum of the masses of light and strange quark using improved staggered quarks. Our calculation uses 2+1 flavours of dynamical quarks. The effects of the dynamical quarks are clearly visible.
Pair emission from bare magnetized strange stars
Melrose, D B; Peres-Menezes, D
2006-01-01
The dominant emission from bare strange stars is thought to be electron-positron pairs, produced through spontaneous pair creation (SPC) in a surface layer of electrons tied to the star by a superstrong electric field. The positrons escape freely, but the electrons are directed towards the star and quickly fill all available states, such that their degeneracy suppresses further SPC. An electron must be reflected and gain energy in order to escape, along with the positron. Each escaping electron leaves a hole that is immediately filled by another electron through SPC. We discuss the collisional processes that produce escaping electrons. When the Landau quantization of the motion perpendicular to the magnetic field is taken into account, electron-electron collisions can lead to an escaping electron only through a multi-stage process involving higher Landau levels. Although the available estimates of the collision rate are deficient in several ways, it appears that the rate is too low for electron-electron colli...
Strangeness suppression in the unquenched quark model
Bijker, Roelof; Santopinto, Elena
2016-01-01
In this contribution, we discuss the strangeness suppression in the proton in the framework of the unquenched quark model. The theoretical results are in good agreement with the values extracted from CERN and JLab experiments.
Strangeness suppression in the unquenched quark model
Bijker, Roelof; García-Tecocoatzi, Hugo; Santopinto, Elena
2016-07-01
In this contribution, we discuss the strangeness suppression in the proton in the framework of the unquenched quark model. The theoretical results are in good agreement with the values extracted from CERN and JLab experiments.
Strange Quark Matter Status and Prospects
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.
Strange quark matter in a chiral SU(3) quark mean field model
Wang, P.; Lyubovitskij, V. E.; Gutsche, Th.; Faessler, Amand
2002-01-01
We apply the chiral SU(3) quark mean field model to investigate strange quark matter. The stability of strange quark matter with different strangeness fraction is studied. The interaction between quarks and vector mesons destabilizes the strange quark matter. If the strength of the vector coupling is the same as in hadronic matter, strangelets can not be formed. For the case of beta equilibrium, there is no strange quark matter which can be stable against hadron emission even without vector m...
Gaussian Anisotropy In Strange Quark Stars
Panahi, H.; Monadi, R.; Eghdami, I.
2015-01-01
In this paper for studying the anisotropic strange quark stars, we assume that the radial pressure inside the anisotropic star is a superposition of pressure in an isotropic case plus a Gaussian perturbation term. Considering a proportionality between electric charge density and the density of matter, we solve the TOV equation for different cases numerically. Our results indicate that anisotropy increases the maximum mass $M_{max}$ and also its corresponding radius $R$ for a typical strange q...
Strange quark content of the nucleon and dark matter searches
Young, R. D.
2013-01-01
The strange quark scalar content plays an important role in both the description of nucleon structure and in the determination of dark matter direct detection cross sections. As a measure of the strange-quark contribution to the nucleon mass, the strange-quark sigma term (\\sigma_s) provides important insight into the nature of mass generation in QCD. The phenomenological determination of \\sigma_s exhibits a wide range of variation, with values suggesting that the strange quark contributes any...
Clustered Quark Matter Calculation for Strange Quark Matter
Na, Xuesen
2009-01-01
Motivated by the need for a solid state strange quark matter to better explain some observational phenomena, we discussed possibility of color singlet cluster formation in cold strange quark matter by a rough calculation following the excluded volume method proposed by Clark et al (1986) and adopted quark mass density dependent model with cubic scaling. It is found that 70% to 75% of volume and 80% to 90% of baryon number is in clusters at temperature from 10MeV to 50MeV and 1 to 10 times nuclear density.
Strange quark matter and quark stars with the Dyson-Schwinger quark model
Chen, H; Schulze, H -J
2016-01-01
We calculate the equation of state of strange quark matter and the interior structure of strange quark stars in a Dyson-Schwinger quark model within rainbow or Ball-Chiu vertex approximation. We emphasize constraints on the parameter space of the model due to stability conditions of ordinary nuclear matter. Respecting these constraints, we find that the maximum mass of strange quark stars is about 1.9 solar masses, and typical radii are 9--11 km. We obtain an energy release as large as $3.6 \\times 10^{53}\\,\\text{erg}$ from conversion of neutron stars into strange quark stars.
Seismic Search for Strange Quark Matter
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.
Photon emissivity of the electrosphere of bare strange stars
Harko, T.; Cheng, KS
2005-01-01
We consider the spectrum, emissivity, and flux of the electromagnetic radiation emitted by the thin electron layer (the electrosphere) at the surface of a bare strange star. In particular, we carefully consider the effect of the multiple and uncorrelated scattering on the radiation spectrum (the Landau-Pomeranchuk-Migdal effect), together with the effect of the strong electric field at the surface of the star. The presence of the electric field strongly influences the radiation spectrum emitt...
Strange quark matter in explosive astrophysical systems
Sagert, I; Hempel, M; Pagliara, G; Schaffner-Bielich, J; Thielemann, F -K; Liebendörfer, M
2010-01-01
Explosive astrophysical systems, such as supernovae or compact star binary mergers, provide conditions where strange quark matter can appear. The high degree of isospin asymmetry and temperatures of several MeV in such systems may cause a transition to the quark phase already around saturation density. Observable signals from the appearance of quark matter can be predicted and studied in astrophysical simulations. As input in such simulations, an equation of state with an integrated quark matter phase transition for a large temperature, density and proton fraction range is required. Additionally, restrictions from heavy ion data and pulsar observation must be considered. In this work we present such an approach. We implement a quark matter phase transition in a hadronic equation of state widely used for astrophysical simulations and discuss its compatibility with heavy ion collisions and pulsar data. Furthermore, we review the recently studied implications of the QCD phase transition during the early post-bou...
Search for nuclei containing two strange quarks
International Nuclear Information System (INIS)
This paper discusses a search for nuclei containing two strange quarks performed at Brookhaven National Laboratory. The goals and approach of experiment E885 are reviewed. Preliminary missing mass spectra for a subset of the data are presented, showing sensitivity for Ξ hypernuclei and H particle searches. Existence of an angular correlation between pions in the sequential decay of ΛΛ hypernuclei is suggested on theoretical grounds
Constraints on the Existence of Strange Quark Stars
Balberg, Shmuel
1997-01-01
Creation of strange quark stars through strong interaction deconfinement is studied based on modern estimates of hyperon formation in neutron stars. The hyperon abundance is shown to be large enough so that if strange quark matter (SQM) is the true ground state of matter, the deconfinement density should be at most 2.5-3 times the nuclear saturation density. If so, deconfinement occurs in neutron stars at birth, and all neutron stars must be strange quark stars. Alternatively, sould observati...
Determination of light and strange quark masses from two-flavour dynamical lattice QCD
International Nuclear Information System (INIS)
We compute the light and strange quark masses ml =(mu+md)/2 and ms, respectively, in unquenched lattice QCD with Nf=2 flavours of light dynamical quarks. The renormalisation constants, which convert bare quark masses into renormalised quark masses, are computed nonperturbatively, including the effect of quark-line disconnected diagrams. We obtain mlMS-bar (2 GeV)=4.7(2)(3) MeV and msMS-bar (2 GeV)=119(5)(8) MeV, using r0=0.467 fm to set the scale
Determining the strange quark mass for 2-flavour QCD
International Nuclear Information System (INIS)
Using the O(a) Symanzik improved action an estimate is given for the strange quark mass for unquenched (nf=2) QCD. The determination is via the axial Ward identity (AWI) and includes a non-perturbative evaluation of the renormalisation constant. Numerical results have been obtained at several lattice spacings, enabling the continuum limit to be taken. Our results indicate a value for the strange quark mass (in the MS-bar -scheme at a scale of 2 GeV) in the range 100 - 130 MeV. A comparison is also made with other recent lattice determinations of the strange quark mass using dynamical sea quarks
Determining the strange quark mass for 2-flavour QCD
International Nuclear Information System (INIS)
Using the O(a) Symanzik improved action an estimate is given for the strange quark mass for unquenched (nf=2) QCD. The determination is via the axial Ward identity (AWI) and includes a non-perturbative evaluation of the renormalisation constant. Numerical results have been obtained at several lattice spacings, enabling the continuum limit to be taken. Our results indicate a value for the strange quark mass (in the anti M anti S-scheme at a scale of 2 GeV) in the range 100 - 130 MeV. A comparison is also made with other recent lattice determinations of the strange quark mass using dynamical sea quarks. (orig.)
Gaussian Anisotropy In Strange Quark Stars
Panahi, H; Eghdami, I
2015-01-01
In this paper for studying the anisotropic strange quark stars, we assume that the radial pressure inside the anisotropic star is a superposition of pressure in an isotropic case plus a Gaussian perturbation term. Considering a proportionality between electric charge density and the density of matter, we solve the TOV equation for different cases numerically. Our results indicate that anisotropy increases the maximum mass $M_{max}$ and also its corresponding radius $R$ for a typical strange quark star. According to our calculations, an anisotropy amplitude of $A=3\\times10^{33}Nm^{-2}$ with a standard deviation of $\\sigma=3\\times10^{3}m$ leads to a neutron star of 1.97$M_{\\odot}$. Furthermore, electric charge not only increases the maximum mass and its corresponding radius, but also raises up the anisotropy factor. We can see that the tangential pressure $p_{t}$ and anisotropy factor $\\Delta$ unlike the radial pressure $p_{r}$ have a maximum on the surface and this maximum increases by adding electric charge e...
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.
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.
Strangeness at high temperatures: from hadrons to quarks.
Bazavov, A; Ding, H-T; Hegde, P; Kaczmarek, O; Karsch, F; Laermann, E; Maezawa, Y; Mukherjee, Swagato; Ohno, H; Petreczky, P; Schmidt, C; Sharma, S; Soeldner, W; Wagner, M
2013-08-23
Appropriate combinations of up to fourth order cumulants of net strangeness fluctuations and their correlations with net baryon number and electric charge fluctuations, obtained from lattice QCD calculations, have been used to probe the strangeness carrying degrees of freedom at high temperatures. For temperatures up to the chiral crossover, separate contributions of strange mesons and baryons can be well described by an uncorrelated gas of hadrons. Such a description breaks down in the chiral crossover region, suggesting that the deconfinement of strangeness takes place at the chiral crossover. On the other hand, the strangeness carrying degrees of freedom inside the quark gluon plasma can be described by a weakly interacting gas of quarks only for temperatures larger than twice the chiral crossover temperature. In the intermediate temperature window, these observables show considerably richer structures, indicative of the strongly interacting nature of the quark gluon plasma. PMID:24010429
Quark mass density- and temperature- dependent model for bulk strange quark matter
al, Yun Zhang et.
2002-01-01
It is shown that the quark mass density-dependent model can not be used to explain the process of the quark deconfinement phase transition because the quark confinement is permanent in this model. A quark mass density- and temperature-dependent model in which the quark confinement is impermanent has been suggested. We argue that the vacuum energy density B is a function of temperature. The dynamical and thermodynamical properties of bulk strange quark matter for quark mass density- and temper...
A Possible Resolution of the Strange Quark Polarization Puzzle ?
Leader, Elliot; Stamenov, Dimiter B
2011-01-01
We propose a possible resolution of the strange quark polarization puzzle i.e. of the contradiction between the negative polarized strange quark density obtained from analyses of inclusive DIS data and the positive values obtained from combined analyses of inclusive and semi-inclusive SIDIS data using de Florian et. al. (DSS) fragmentation functions. To this end the results of a new combined NLO QCD analysis of the polarized inclusive and semi-inclusive DIS data, using the Hirai et. al. (HKNS) fragmentation functions, are presented. It is demonstrated that the polarized strange quark density is very sensitive to the kaon fragmentation functions, and if the set of HKNS fragmentation functions is used, the polarized strange quark density from the combined analysis turns out to be negative and well consistent with values obtained from the pure DIS analyses.
Possible resolution of the strange quark polarization puzzle?
Leader, Elliot; Sidorov, Alexander V.; Stamenov, Dimiter B.
2011-07-01
The strange quark polarization puzzle, i.e. the contradiction between the negative polarized strange quark density obtained from analyses of inclusive deep inelastic scattering data and the positive values obtained from combined analyses of inclusive and semi-inclusive deep inelastic scattering data using de Florian, Sassot, Stratmann fragmentation functions, is discussed. To this end the results of a new combined next-to-leading order QCD analysis of the polarized inclusive and semi-inclusive deep inelastic scattering data, using the Hirai, Kumano, Nagai, Sudoh (HKNS) fragmentation functions, are presented. It is demonstrated that the polarized strange quark density is very sensitive to the kaon fragmentation functions, and if the set of HKNS fragmentation functions is used, the polarized strange quark density obtained from the combined analysis turns out to be negative and well consistent with values obtained from the pure deep inelastic scattering analyses.
Possible resolution of the strange quark polarization puzzle?
International Nuclear Information System (INIS)
The strange quark polarization puzzle, i.e. the contradiction between the negative polarized strange quark density obtained from analyses of inclusive deep inelastic scattering data and the positive values obtained from combined analyses of inclusive and semi-inclusive deep inelastic scattering data using de Florian, Sassot, Stratmann fragmentation functions, is discussed. To this end the results of a new combined next-to-leading order QCD analysis of the polarized inclusive and semi-inclusive deep inelastic scattering data, using the Hirai, Kumano, Nagai, Sudoh (HKNS) fragmentation functions, are presented. It is demonstrated that the polarized strange quark density is very sensitive to the kaon fragmentation functions, and if the set of HKNS fragmentation functions is used, the polarized strange quark density obtained from the combined analysis turns out to be negative and well consistent with values obtained from the pure deep inelastic scattering analyses.
Strange quark matter:Business as usual or phase transition?
Torrieri, Giorgio
2011-01-01
We give an overview of some results presented at the Strange Quark Matter 2011 conference in Krakow, and interpret them in light of the search of the search for a QCD deconfinement phase transition in heavy ion collisions
Strangeness and quark gluon plasma: Aspects of theory and experiment
International Nuclear Information System (INIS)
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.)
Higher dimensional strange quark matter solutions in self creation cosmology
Şen, R.; Aygün, S.
2016-03-01
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.
RX J1856.5-3754: A Strange Star with Solid Quark Surface?
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.
16th International Conference on Strangeness in Quark Matter
2016-01-01
Topical conference on Strangeness and Heavy Flavor production in Heavy-Ion Collisions The conference will focus on new experimental and theoretical developments on the role of strange and heavy-flavour quarks in proton-proton and in heavy-ion collisions, and in astrophysical phenomena. New results are expected, from the LHC, from RHIC and from other experimental programs. The 16th International Conference on Strangeness in Quark Matter, follows the recent events of 2015 in Dubna, 2013 in Birmingham, and 2011 in Cracow.
First determination of the strange and light quark masses from full lattice QCD
International Nuclear Information System (INIS)
We compute the strange quark mass ms and the average of the u and d quark masses m using full lattice QCD with three dynamical quarks combined with the experimental values for the π and K masses. The simulations have degenerate u and d quarks with masses mu=md≡m as low as ms/8, and two different values of the lattice spacing. The bare lattice quark masses obtained are converted to the MS scheme using perturbation theory at O(αS). Our results are msMS(2 GeV)=76(0)(3)(7)(0) MeV, mMS(2 GeV)=2.8(0)(1)(3)(0) MeV, and ms/m=27.4(1)(4)(0)(1), where the errors are from statistics, simulation, perturbation theory, and electromagnetic effects, respectively
First determination of the strange and light quark masses from full lattice QCD
Aubin, C; Davies, C; DeTar, C E; Gottlieb, S; Gray, A; Gregory, E; Hein, J; Heller, U; Hetrick, J E; Lepage, G; Mason, Q; Osborn, J; Sugar, R; Toussaint, D
2004-01-01
We compute the strange quark mass $m_s$ and the average of the $u$ and $d$ quark masses $\\hat m$ using full lattice QCD with three dynamical quarks combined with experimental values for the pion and kaon masses. The simulations have degenerate $u$ and $d$ quarks with masses $m_u=m_d\\equiv \\hat m$ as low as $m_s/8$, and two different values of the lattice spacing. The bare lattice quark masses obtained are converted to the $\\msbar$ scheme using perturbation theory at $O(alpha_s)$. Our results are: $m_s^\\msbar$(2 GeV) = 76(0)(3)(7)(0) MeV, $\\hat m^\\msbar$(2 GeV) = 2.8(0)(1)(3)(0) MeV and $m_s/\\hat m$ = 27.4(1)(4)(0)(1), where the errors are from statistics, simulation, perturbation theory, and electromagnetic effects, respectively.
New analysis concerning the strange quark polarization puzzle
Leader, Elliot; Stamenov, Dimiter B
2014-01-01
The fact that analyses of semi-inclusive deep inelastic scattering suggest that the strange quark polarization $\\Delta s(x) + \\Delta \\bar{s}(x)$ is positive in the measured region of Bjorken x, whereas all analyses of inclusive deep inelastic scattering yield significantly negative values of this quantity, is known as the "strange quark polarization puzzle". We have re-analysed the world data on inclusive deep inelastic scattering, including the COMPASS 2010 proton data on the spin asymmetries, and for the first time, the new extremely precise JLab CLAS data on the proton and deuteron spin structure functions. Despite allowing, in our parametrization, for a possible sign change, our results confirm that the inclusive data yield significantly negative values for the strange quark polarization.
Strange Quark Magnetic Moment of the Nucleon at Physical Point
Sufian, Raza Sabbir; Alexandru, Andrei; Draper, Terrence; Liu, Keh-Fei; Liang, Jian
2016-01-01
We report a lattice QCD calculation of the strange quark contribution to the proton's magnetic moment and charge radius. This analysis presents the first direct determination of strange electromagnetic form factors including the physical pion mass with chiral fermions. 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 \\,\\text{GeV}^2 \\lesssim Q^2 \\lesssim 1.31 \\,\\text{GeV}^2 $. The finite lattice spacing and finite volume corrections are included in a global fitting with $17$ valence quark masses on three lattices with different lattice spacings, different volumes, and three sea quark masses including one at the physical pion mass. We obtain the strange magnetic moment $G^s_M(0) = - 0.073(17)(08)\\, \\mu_N$. The 4-sigma precision in statistics is achieved partly due to the low-mode averaging of the quark loop and low-mode substitution of the nucleon source to improve the statistics ...
The Strange Quark Problem in the Framework of Statistical Distributions
Buccella, F; Rosa, L
2000-01-01
A large class of polarized and unpolarized deep inelastic data is successfully described with Fermi-Dirac functions for the non-diffractive part of quark parton distributions. The NLO approach used here improves the agreement with experiment of the previous LO work. We get a broader distribution for the strange parton s(x) than for sbar(x).
The strange quark problem in the framework of statistical distributions
International Nuclear Information System (INIS)
A large class of polarized and unpolarized deep inelastic data is successfully described with Fermi-Dirac functions for the non-diffractive part od quark parton distributions. The NLO approach used improves the agreement with experiment of the previous LO work. We get a broader distribution for the strange parton s(x) than for anti-s(x)
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.
Penta-quark States with Strangeness, Hidden Charm and Beauty
Wu, Jia-Jun
2015-01-01
The classical quenched quark models with three constituent quarks provide a good description for the baryon spatial ground states, but fail to reproduce the spectrum of baryon excited states. More and more evidences suggest that unquenched effects with multi-quark dynamics are necessary ingredients to solve the problem. Several new hyperon resonances reported recently could fit in the picture of penta-quark states. Based on this picture, some new hyperon excited states were predicted to exist; meanwhile with extension from strangeness to charm and beauty, super-heavy narrow $N^*$ and $\\Lambda^*$ resonances with hidden charm or beauty were predicted to be around 4.3 and 11 GeV, respectively. Recently, two of such $N^*$ with hidden charm might have been observed by the LHCb experiment. More of those states are expected to be observed in near future. This opens a new window in order to study hadronic dynamics for the multi-quark states.
Penta-Quark States with Strangeness, Hidden Charm and Beauty
Wu, Jia-Jun; Zou, Bing-Song
The classical quenched quark models with three constituent quarks provide a good description for the baryon spatial ground states, but fail to reproduce the spectrum of baryon excited states. More and more evidences suggest that unquenched effects with multi-quark dynamics are necessary ingredients to solve the problem. Several new hyperon resonances reported recently could fit in the picture of penta-quark states. Based on this picture, some new hyperon excited states were predicted to exist; meanwhile with extension from strangeness to charm and beauty, super-heavy narrow N* and Λ* resonances with hidden charm or beauty were predicted to be around 4.3 and 11 GeV, respectively. Recently, two of such N* with hidden charm might have been observed by the LHCb experiment. More of those states are expected to be observed in near future. This opens a new window in order to study hadronic dynamics for the multi-quark states.
Flavour symmetry breaking and tuning the strange quark mass for 2+1 quark flavours
Energy Technology Data Exchange (ETDEWEB)
Bietenholz, W. [Universidad Autonoma de Mexico (Mexico). Inst. de Ciencias Nucleares; Bornyakov, V. [Institute for High Energy Physics, Protovino (Russian Federation); Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Goeckeler, M. [Regensburg Univ. (DE). Inst. fuer Theoretische Physik] (and others)
2010-12-15
QCD lattice simulations with 2+1 flavours typically start at rather large up-down and strange quark masses and extrapolate first the strange quark mass to its physical value and then the updown quark mass. An alternative method of tuning the quark masses is discussed here in which the singlet quark mass is kept fixed, which ensures that the kaon always has mass less than the physical kaon mass. Using group theory the possible quark mass polynomials for a Taylor expansion about the flavour symmetric line are found, which enables highly constrained fits to be used in the extrapolation of hadrons to the physical pion mass. Numerical results confirm the usefulness of this expansion and an extrapolation to the physical pion mass gives hadron mass values to within a few percent of their experimental values. (orig.)
Stability of charged strange quark stars
Energy Technology Data Exchange (ETDEWEB)
Arbañil, José D. V.; Malheiro, Manuel [Departamento de Física, Instituto Tecnológico de Aeronáutica, Centro Técnico Aeroespacial, 12228-900 São José dos Campos, SP (Brazil)
2015-12-17
We investigate the hydrostatic equilibrium and the stability of charged stars made of a charged perfect fluid. The matter contained in the star follows the MIT bag model equation of state and the charge distribution to a power-law of the radial coordinate. The hydrostatic equilibrium and the stability of charged strange stars are analyzed using the Tolman-Oppenheimer-Volkoff equation and the Chandrasekhar’s equation pulsation, respectively. These two equation are modified from their original form to the inclusion of the electric charge. We found that the stability of the star decreases with the increment of the central energy density and with the increment of the amount of charge.
Heavy quark solitons strangeness and symmetry breaking
Momen, A; Subbaraman, A; Momen, Arshad; Schechter, Joseph; Subbaraman, Anand
1994-01-01
We discuss the generalization of the Callan-Klebanov model to the case of heavy quark baryons. The light flavor group is considered to be $SU(3)$ and the limit of heavy spin symmetry is taken. The presence of the Wess-Zumino-Witten term permits the neat development of a picture , at the collective level, of a light diquark bound to a ``heavy" quark with decoupled spin degree of freedom. The consequences of $SU(3)$ symmetry breaking are discussed in detail. We point out that the $SU(3)$ mass splittings of the heavy baryons essentially measure the ``low energy" physics once more and that the comparison with experiment is satisfactory.
Heavy quark solitons: Strangeness and symmetry breaking
International Nuclear Information System (INIS)
We discuss the generalization of the Callan-Klebanov model to the case of heavy quark baryons. The light flavor group is considered to be SU(3) and the limit of heavy spin symmetry is taken. The presence of the Wess-Zumino-Witten term permits the neat development of a picture, at the collective level, of a light diquark bound to a ''heavy'' quark with decoupled spin degree of freedom. The consequences of SU(3) symmetry breaking are discussed in detail. We point out that the SU(3) mass splitting of the heavy baryons essentially measure the ''low energy'' physics once more and that the comparison with experiment is satisfactory
A class of exact strange quark star model
Indian Academy of Sciences (India)
S Thirukkanesh; F C Ragel
2013-08-01
Static spherically symmetric space-time is studied to describe dense compact star with quark matter within the framework of MIT Bag Model. The system of Einstein’s field equations for anisotropic matter is expressed as a new system of differential equations using transformations and it is solved for a particular general form of gravitational potential with parameters. For a particular parameter, as an example, it is shown that the model satisfies all major physical features expected in a realistic star. The generated model also smoothly matches with the Schwarzschild exterior metric at the boundary of the star. It is shown that the generated solutions are useful to model strange quark stars.
The extent of strangeness equilibration in quark gluon plasma
Indian Academy of Sciences (India)
Dipali Pal; Abhijit Sen; Munshi Golam Mustafa; Dinesh Kumar Srivastava
2003-05-01
The evolution and production of strangeness from chemically equilibrating and transversely expanding quark gluon plasma which may be formed in the wake of relativistic heavy-ion collisions is studied with initial conditions obtained from the self screened parton cascade (SSPC) model. The extent of partonic equilibration increases almost linearly with the square of the initial energy density, which can then be scaled with the number of participants.
Fragmentation of Strange Quark Matter in Astrophysical Events
Horvath, J E
2015-01-01
We assess the fragmentation of strange quark matter in astrophysical events, showing that the application of statistical multifragmentation models suggests that most of the fragments (strangelets) should belong to an unstable baryon number $A$. While there are some caveats to be addressed, the flux of strangelets onto the Earth could be orders of magnitude lower than previous estimates, with negative prospects for the ongoing search experiments.
Superconducting phases of strange quark matter in the NJL model
Paulucci, L; Ferrer, E J; de la Incera, V
2013-01-01
We analyze the color-flavor-locked phase of strange quark matter modelled by the three-flavor Nambu-Jona-Lasinio (NJL) framework with and without magnetic field and discuss some additional constraints on the stability scenario when a high magnetic field is applied. We compare the results obtained by employing the MIT Bag Model and discuss the pairing gap behavior and its influence on the equation of state.
Strange quark matter in the Universe and accelerator nuclear beams
International Nuclear Information System (INIS)
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
HERMES measurements of the strange parton distribution and strange quark helicity distribution
Energy Technology Data Exchange (ETDEWEB)
Kravchenko, Polina [PNPI, St. Petersburg (Russian Federation)
2009-07-01
The helicity density of the strange quark sea in the proton has been extracted from measurements of polarized semi-inclusive production of charged kaons in deep inelastic scattering of positrons from a polarized deuteron target. The isoscalar nature of the deuteron target (assuming isospin symmetry) and lack of isospin for strange quarks allows the deuteron target to be used independently without relying on fragmentation models or other experimental data. In the region of measurement of x>0.02 the helicity density is zero within experimental error and the measured first moment of the density is 0.006+/-0.029(stat)+/-0.007(sys)/. The first moment of the axial charge in the measured region is substantially less than that inferred from hyperon semi-leptonc decays.
RX J1856.5-3754 Bare Quark Star or Naked Neutron Star ?
Zane, S; Drake, J J
2003-01-01
Recent Chandra observations have shown that the soft X-ray spectrum from the isolated neutron star RX J1856.5-3754 is featureless and best fitted by a blackbody, in contrast with the predictions of current neutron star atmospheric models. The star distance (~120-140 pc) implies a radiation radius of at most \\~5-6 km, too small for any neutron star equation of state. Proposed explanations for such a small radius include a reduced X-ray emitting region (as a polar cap), or the presence of a more compact object, as a bare quark/strange star. However, both interpretations rely on the presumption that the quark star or the cap radiates a pure blackbody spectrum, and no justification for this assumption has been presented yet. Here we discuss an alternative possibility. Cool neutron stars (T 10^13 G) may suffer a phase transition in the outermost layers. The neutron star is then left bare of the gaseous atmosphere. We computed spectra from naked neutron stars with a surface Fe composition. Depending on B, we found...
Radial stability of anisotropic of strange quark stars
Arbañil, José D V
2016-01-01
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 $\\sigma=p_t-p_r$, where $p_t$ and $p_r$ are respectively the tangential and the radial pressure, are considered: one that is null at the star's surface defined by $p_r(R)=0$, and other that is nonnull on it, namely, $\\sigma_s=0$ and $\\sigma_s\
Connected, Disconnected and Strange Quark Contributions to HVP
Bijnens, 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.
Search for Strange Quark Matter Produced in Relativistic Heavy Ion Collisions
Collaboration, T. A. Armstrong et al. The E864
2000-01-01
We present the final results from Experiment 864 of a search for charged and neutral strange quark matter produced in interactions of 11.5 GeV/c per nucleon Au beams with Pt or Pb targets. Searches were made for strange quark matter with A>4. Approximately 30 billion 10% most central collisions were sampled and no strangelet states with A
Strange quark matter and strangelets in the improved quasiparticle model
International Nuclear Information System (INIS)
In this work, the properties of strange quark matter and strangelets are investigated within the framework of the improved quasiparticle model. The energy per baryon and particle chemical potentials as a function of the quark matter density are given. In particular, within the multiple reflection expansion method, the finite-size effects of strangelets are discussed in detail. The stable radius of a strangelet in the present model is smaller than, but comparable with that of the corresponding nucleus with the same baryon number. With the baryon number increment of stable strangelets, it is found that the surface tension decreases to 33 MeV fm-2 for strangelets with the baryon number greater than 104. (orig.)
Strange Quark Stars as Probe of Dark Matter
Zheng, Hao
2016-01-01
We show that the observation of old strange quark stars (SQSs) can set important limits on the scattering cross sections $\\sigma_q$ between the light quarks and the bosonic non-interacting dark matter (DM). By analyzing $1403$ sets of solitary pulsarlike compact stars in the Milky Way and converting the $\\sigma_q$ into the DM-proton scattering cross sections $\\sigma_p$ based on the effective operator analyses, we find the resulting $\\sigma_p$ limit from the old SQSs could be comparable with that of the current direct detection experiments but much weaker (by several orders of magnitude) than that obtained from the old neutron stars (NSs), which requires an extremely small $\\sigma_p$ far beyond the limits of direct detection experiments. Our findings imply that the old pulsars are favored to be SQSs rather than NSs if the bosonic DM were observed by future terrestrial experiments.
Strange quark matter and strangelets in the improved quasiparticle model
Energy Technology Data Exchange (ETDEWEB)
Wu, Chen [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China); Xu, Renli [Nanjing University, Key Laboratory of Modern Acoustics and Department of Physics, Nanjing (China)
2015-10-15
In this work, the properties of strange quark matter and strangelets are investigated within the framework of the improved quasiparticle model. The energy per baryon and particle chemical potentials as a function of the quark matter density are given. In particular, within the multiple reflection expansion method, the finite-size effects of strangelets are discussed in detail. The stable radius of a strangelet in the present model is smaller than, but comparable with that of the corresponding nucleus with the same baryon number. With the baryon number increment of stable strangelets, it is found that the surface tension decreases to 33 MeV fm{sup -2} for strangelets with the baryon number greater than 10{sup 4}. (orig.)
Using the Moon As A Low-Noise Seismic Detector For Strange Quark Nuggets
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.
Geng, J J; Lu, T
2015-01-01
Strange quark matter (SQM) may be the true ground state of hadronic matter, indicating that the observed pulsars may actually be strange stars, but not neutron stars. According to this SQM hypothesis, the existence of a hydrostatically stable sequence of strange quark matter stars has been predicted, ranging from 1 --- 2 solar mass strange stars, 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 searching for SQM stars. Here we show that due to their extreme compactness, strange planets can spiral very close to their host strange stars, without being tidally disrupted. Like inspiraling neutron stars or black holes, these systems would serve as a new kind of sources for GW bursts, producing strong gravitational waves at the final stage. The events occurring in our local Universe can be detected by the upcoming gravitational wave detectors, such as Advanced LIGO and the Einstein Telescope. This ...
Dibaryons with two strange quarks and one heavy flavor in a constituent quark model
Park, Aaron; Lee, Su Houng
2016-01-01
We investigate the symmetry property and the stability of dibaryons containing two strange quarks and one heavy flavor with $I=\\frac{1}{2}$. We construct the wave function of the dibaryon in two ways. First, we directly construct the color and spin state of the dibaryon starting from the four possible SU(3) flavor state. Second, we consider the states composed of five light quarks, and then construct the wave function of the dibaryon by adding one heavy quark. The stability of the dibaryon against the strong decay into two baryons is discussed by using variational method in a constituent quark model with confining and hyperfine potential. We find that for all configurations with S=0,1,2, the ground states of the dibaryons are the sum of two baryons, and there are no compact bound state that is stable against the strong decay.
Bulk viscosity of strange quark matter in density dependent quark mass model
Indian Academy of Sciences (India)
J D Anand; N Chandrika Devi; V K Gupta; S Singh
2000-05-01
We have studied the bulk viscosity of strange quark matter in the density dependent quark mass model (DDQM) and compared results with calculations done earlier in the MIT bag model where , masses were neglected and ﬁrst order interactions were taken into account. We ﬁnd that at low temperatures and high relative perturbations, the bulk viscosity is higher by 2 to 3 orders of magnitude while at low perturbations the enhancement is by 1–2 order of magnitude as compared to earlier results. Also the damping time is 2–3 orders of magnitude lower implying that the star reaches stability much earlier than in MIT bag model calculations.
Indian Academy of Sciences (India)
V K Gupta; Asha Gupta; S Singh; J D Anand
2003-10-01
We report on the study of the mass–radius (–) relation and the radial oscillations of magnetized proto strange stars. For the quark matter we have employed the very recent modiﬁcation, the temperature- and density-dependent quark mass model of the well-known density-dependent quark mass model. We ﬁnd that the effect of magnetic ﬁeld, both on the maximum mass and radial frequencies, is rather small. Also a proto strange star, whether magnetized or otherwise, is more likely to evolve into a strange star rather than transform into a black hole.
Equilibrium and stability of charged strange quark stars
Arbañil, José D V
2015-01-01
The hydrostatic equilibrium and the stability against radial perturbation of charged strange quark stars composed of a charged perfect fluid are studied. For this purpose, it is considered that the perfect fluid follows the MIT bag model equation of state and the radial charge distribution follows a power-law. The hydrostatic equilibrium and the stability of charged strange stars are investigated through the numerical solutions of the Tolman-Oppenheimer-Volkoff equation and the Chandrasekhar's pulsation equation, being these equations modified from their original form to include the electrical charge. In order to appreciably affect the stellar structure, it is found that the total charge should be of order $10^{20}[\\rm C]$, implying an electric field of around $10^{22}[\\rm V/m]$. We found the electric charge that produces considerable effect on the structure and stability of the object is close to the star's surface. We obtain that for a range of central energy density the stability of the star decreases with...
Charm and Strangeness with Heavy-Quark Spin Symmetry
Tolos, L; Nieves, J; Romanets, O; Salcedo, L L
2012-01-01
We study charmed and strange baryon resonances that are generated dynamically within a unitary meson-baryon coupled-channel model which incorporates heavy-quark spin symmetry. This is accomplished by extending the SU(3) Weinberg-Tomozawa chiral Lagrangian to SU(8) spin-flavor symmetry and implementing a strong flavor symmetry breaking. The model generates dynamically resonances with negative parity in all the isospin, spin, and strange and charm sectors that one can form from an s-wave interaction between pseudoscalar and vector meson multiplets with $1/2^+$ and $3/2^+$ baryons. Our results are compared with experimental data from several facilities as well as with other theoretical models. Moreover, we obtain the properties of charmed pseudoscalar and vector mesons in dense matter within this coupled-channel unitary effective model by taking into account Pauli-blocking effects and meson self-energies in a self-consistent manner. We obtain the open-charm meson spectral functions in this dense nuclear environm...
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.)
Relativistic simulations of compact object mergers for nucleonic matter and strange quark matter
International Nuclear Information System (INIS)
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.)
Dibaryons with two strange quarks and total spin zero in a constituent quark model
Park, Woosung; Park, Aaron; Lee, Su Houng
2016-04-01
We investigate the symmetry property and construct the wave function of the dibaryon states containing two strange quarks with S =0 in both the flavor SU(3) symmetric and breaking cases. We discuss how the color ⊗ isospin ⊗ spin states of dibaryon in the symmetry broken case of flavor SU(3) can be extracted from the fully antisymmetric states in flavor SU(3). The stability of the dibaryon against the strong decay into two baryons is then discussed, by using the variational method within a constituent quark model with confining and color-spin interactions. To compare our results with those from lattice QCD in the flavor SU(3) limit, we search for the stable H-dibaryon in a wide range of π meson masses. We find that with the given potential, there is no compact six-quark dibaryon state in the SU(3) flavor symmetry broken case with realistic quark masses as well as in the flavor SU(3) symmetric case in a wide range of quark masses.
A tale of two skyrmions: The nucleon's strange quark content in different large Nc limits
International Nuclear Information System (INIS)
The nucleon's strange quark content comes from closed quark loops, and hence should vanish at leading order in the traditional large Nc (TLNC) limit. Quark loops are not suppressed in the recently proposed orientifold large Nc (OLNC) limit, and thus the strange quark content should be non-vanishing at leading order. The Skyrme model is supposed to encode the large Nc behavior of baryons, and can be formulated for both of these large Nc limits. There is an apparent paradox associated with the large Nc behavior of strange quark matrix elements in the Skyrme model. The model only distinguishes between the two large Nc limits via the Nc scaling of the couplings and the Witten-Wess-Zumino term, so that a vanishing leading order strange matrix element in the TLNC limit implies that it also vanishes at leading order in the OLNC limit, contrary to the expectations based on the suppression/non-suppression of quark loops. The resolution of this paradox is that the Skyrme model does not include the most general type of meson-meson interaction and, in fact, contains no meson-meson interactions which vanish for the TLNC limit but not the OLNC. The inclusion of such terms in the model yields the expected scaling for strange quark matrix elements
PREFACE: SQM2007 International Conference on Strangeness in Quark Matter
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
Looking for Strange Quark Matter in Cosmic Rays.
Directory of Open Access Journals (Sweden)
Bezshapov S.P.
2013-06-01
Full Text Available Usually it is supposed that the definition of the CR mass composition in knee region is the key to problem of CR spectrum modification in this range. However tens of the experiments were done for the last half of century and have not decided this problem up to now. The possible causes of fiasco and arguments in favour of necessity to reformulate attack method are discussed, taking into account a new experimental data about fine structure of CR spectrum and EAS core investigations. The possible presence of the exotic processes in the area of a knee is discussed. If exotic component really exists in CR then impossible to formulate correctly more common problem of mass composition without solving this one. It is represented, that the problem of presence of an exotic component in CR should be solved easier than a CR composition problem. The observational basis is discussed. The hypothesis of strange quark matter in CR is suggested for the exotic component.
International Nuclear Information System (INIS)
Understanding the nucleon structure is currently one of the main challenges encountered in nuclear physics. The present work represents a contribution to the study of the nucleon structure and deals, in particular, with the study of the role of strange quarks in the nucleon. The latter can be investigated by determining the strange quark distribution in the nucleon as well as the contribution of the spins of strange quarks to the nucleon spin. This work first presents a measurement of the nucleon spin performed via Deeply Inelastic Scattering (DIS) of a muon beam off polarized proton and deuterium targets. The result is found to be strongly dependent on the quark fragmentation functions into hadrons (FFs), which define the probability that a quark of a given flavour fragments into a final state hadron. The FFs are poorly known, in particular, the FF of strange quark into kaons, which play an important role in the determination of the nucleon spin. In deep inelastic scattering process, the access to the FFs is provided by the hadron multiplicities which, in turn, define the average number of hadrons produced per DIS event. Pion and kaon multiplicities have been extracted versus different kinematic variables, using DIS data collected by deeply inelastic scattering of a 160 GeV/c muons off a deuterium target. A first Leading Order (LO) extraction of the fragmentation functions has then been performed using the measured pion and kaon multiplicities. (author)
Combustion of a neutron star into a strange quark star: The neutrino signal
Pagliara, G.; M. Herzog; Roepke, F. K.
2013-01-01
There are strong indications that the process of conversion of a neutron star into a strange quark star proceeds as a strong deflagration implying that in a few milliseconds almost the whole star is converted. Starting from the three-dimensional hydrodynamic simulations of the combustion process which provide the temperature profiles inside the newly born strange star, we calculate for the first time the neutrino signal that is to be expected if such a conversion process takes place. The neut...
Multi-strange-quark states at ultra-relativistic heavy-ion collisions
Indian Academy of Sciences (India)
J P Coffin; C Kuhn; B Hippolyte; J Baudot; I Belikov
2003-05-01
We examine the possibility of producing and evidencing exotic strange matter (strangelets and metastable multi-hypernuclear objects, MEMO’s), including also pure hyperonic bound states ((), (Ξ )), at RHIC and LHC. Simulations are presented to estimate the sensitivity of the STAR and ALICE experiments to the detection of these objects, focusing mainly on metastable short-lived (weak decaying) strange dibaryons, with a particular emphasis on the -dibaryon, a six quark-bag bound state (uuddss).
Search for Exotic Strange Quark Matter in High Energy Nuclear Reactions
E687 Collaboration; al, T. A. Armstrong et
1997-01-01
We report on a search for metastable positively and negatively charged states of strange quark matter in Au+Pb reactions at 11.6 A GeV/c in experiment E864. We have sampled approximately six billion 10% most central Au+Pb interactions and have observed no strangelet states (baryon number A < 100 droplets of strange quark matter). We thus set upper limits on the production of these exotic states at the level of 1-6 x 10^{-8} per central collision. These limits are the best and most model indep...
A determination of the strange quark mass for unquenched clover fermions using the AWI
International Nuclear Information System (INIS)
Using the O(a) Symanzik improved action an estimate is given for the strange quark mass for unquenched (nf=2) QCD. The determination is via the axial Ward identity (AWI) and includes a non-perturbative evaluation of the renormalisation constant. Numerical results have been obtained at several lattice spacings, enabling the continuum limit to be taken. Results indicate a value for the strange quark mass (in the MS-scheme at a scale of 2 GeV) in the range 100-130 MeV. (orig.)
Pion- and strangeness-baryon $\\sigma$ terms in the extended chiral constituent quark model
An, C. S.; Saghai, B.
2014-01-01
Within an extended chiral constituent quark formalism, we investigate contributions from all possible five-quark components in the octet baryons to the pion-baryon ($\\sigma_{\\pi B}$) and strangeness-baryon ($\\sigma_{s B}$) sigma terms; $B \\equiv N,~\\Lambda,~\\Sigma,~\\Xi$. The probabilities of the quark-antiquark components in the ground-state baryon octet wave functions are calculated by taking the baryons to be admixtures of three- and five-quark components, with the relevant transitions hand...
Using the Moon and Mars as Giant Detectors for Strange Quark Nuggets
Chui, Talso; Penanen, Konstantin; Strayer, Don; Banerdt, Bruce; Tepliz, Vigdor; Herrin, Eugene
2004-01-01
On the Earth, the detectability of small seismic signals is limited by pervasive seismic background noise, caused primarily by interactions of the atmosphere and oceans with the solid surface. Mars, with a very thin atmosphere and no ocean is expected to have a noise level at least an order of magnitude lower than the Earth, and the airless Moon is even quieter still. These pristine low-vibration environments are ideal for searching for nuggets of "strange quark matter." Strange quark matter was postulated by Edward Witten [Phys. Rev. D30, 272, 1984] as the lowest possible energy state of matter. It would be made of up, down, and strange quarks, instead of protons and neutrons made only of up and down quarks. It would have nuclear densities, and hence be difficult to detect. Micron-sized nuggets would weigh in the ton range. As suggested by de Rujula and Glashow [Nature 312 (5996): 734, 1984], a massive strange quark nugget can generate a trail of seismic waves, as it traverses a celestial body. We discuss the mission concept for deploying a network of sensitive seismometers on Mars and on the Moon for such a search.
Analysis of semileptonic decays and EMC data. No real evidence for strange quarks in the proton
International Nuclear Information System (INIS)
A proton model with three valence quarks, a sea of nonstrange quark-antiquark pairs and no strange quark is shown to fit all the EMC and semileptonic baryon decay data used in previous analyses. Conclusions requiring strange quarks in the proton are shown to depend crucially on a model-dependent assumption, invalid for this model, that SU(3) symmetry relates matrix elements of charge and neutral axial currents. The nonstrange sea breaks SU(3) badly and contributes to the neutral current matrix elements relevant to the semileptonic decays. Thus the standard SU(3) analysis of semileptonic decays holds for this model but gives no information on the sea contribution to EMC. (author)
Strange quark mass from the invariant mass distribution of Cabibbo-suppressed tau decays
Energy Technology Data Exchange (ETDEWEB)
Chen, S.; Davier, M.; Hoecker, A. [Laboratoire de l' Accelerateur Lineaire, 91 - Orsay (France); Gamiz, E.; Prades, J. [Granada Univ., Dept. de Fisica Teorica y del Cosmos (Spain); Pich, A. [Valencia Univ. (Spain). Dept. de Fisica Teorica
2001-06-01
Quark mass corrections to the {tau} hadronic width play a significant role only for the strange quark, hence providing a method for determining its mass. The experimental input is the vector plus axial-vector strange spectral function derived from a complete study of tau decays into strange hadronic final states performed by ALEPH. New results on strange decay modes from other experiments are also incorporated. The present analysis determines the strange quark mass at the M{sub {tau}} mass scale using moments of the spectral function. Justified theoretical constraints are applied to the nonperturbative components and careful attention is paid to the treatment of the perturbative expansions of the moments which exhibit convergence problems. The result obtained, m{sub s} (M{sup 2}{sub {tau}}) = (120 {+-} 11{sub exp} {+-} 8v{sub us} {+-} 19th) MeV (120{sup +21}{sub -26}) MeV, is stable over the scale from M{tau} down to about 1.4 GeV. Evolving this result to customary scales yields m{sub s}(1 GeV{sup 2}) (160{sup +28}{sub -35}) MeV and m{sub s}(4 GeV{sup 2}) = (116{sup +20}{sub -25}) MeV. (authors)
Strange quark mass from the invariant mass distribution of Cabibbo-suppressed tau decays
International Nuclear Information System (INIS)
Quark mass corrections to the τ hadronic width play a significant role only for the strange quark, hence providing a method for determining its mass. The experimental input is the vector plus axial-vector strange spectral function derived from a complete study of tau decays into strange hadronic final states performed by ALEPH. New results on strange decay modes from other experiments are also incorporated. The present analysis determines the strange quark mass at the Mτ mass scale using moments of the spectral function. Justified theoretical constraints are applied to the nonperturbative components and careful attention is paid to the treatment of the perturbative expansions of the moments which exhibit convergence problems. The result obtained, ms (M2τ) = (120 ± 11exp ± 8vus ± 19th) MeV (120+21-26) MeV, is stable over the scale from Mτ down to about 1.4 GeV. Evolving this result to customary scales yields ms(1 GeV2) (160+28-35) MeV and ms(4 GeV2) = (116+20-25) MeV. (authors)
An interacting quark-diquark model. Strange and nonstrange baryon spectroscopy and other observables
De Sanctis, M; Vsevolodovna, R Magaña; Saracco, P; Santopinto, E
2016-01-01
We describe the relativistic interacting quark-diquark model formalism and its application to the calculation of strange and nonstrange baryon spectra. The results are compared to the existing experimental data. We also discuss the application of the model to the calculation of other baryon observables, like baryon magnetic moments, open-flavor strong decays and baryon masses with self-energy corrections.
[Search for strange quark matter and antimatter produced in high energy heavy ion collisions
International Nuclear Information System (INIS)
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
Properties of color-flavor locked strange quark matter in an external strong magnetic field
Institute of Scientific and Technical Information of China (English)
崔帅帅; 彭光雄; 陆振烟; 彭程; 徐建峰
2015-01-01
The properties of color-flavor locked strange quark matter in an external strong magnetic field are investigated in a quark model with density-dependent quark masses. Parameters are determined by stability arguments. It is found that the minimum energy per baryon of the color-flavor locked (MCFL) matter decreases with increasing magnetic-field strength in a certain range, which makes MCFL matter more stable than other phases within a proper magnitude of the external magnetic field. However, if the energy of the field itself is added, the total energy per baryon will increase.
Stolarski, M
2014-01-01
The HERMES collaboration in Phys. Rev. D89 (2014) 097101 extracted information about the strange quark density in the nucleon. One of the main results is an observation that the shape of the extracted density is very different from the shapes of the strange quark density from global QCD fits and also from that of the light antiquarks. In this paper systematic studies on the HERMES published multiplicity of pion and kaon data are presented. It is shown that the conclusions concerning the strange quark distribution in the nucleon reached in Phys. Rev. D89 (2014) 097101 are at the moment premature.
The strange and light quark contributions to the nucleon mass from lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Bali, Gunnar S.; Collins, Sara; Goeckeler, Meinulf [Regensburg Univ. (DE). Inst. fuer Theoretische Physik] (and others)
2011-12-15
We determine the strangeness and light quark fractions of the nucleon mass by computing the quark line connected and disconnected contributions to the matrix elements m{sub q} left angle N vertical stroke anti qq vertical stroke N right angle in lattice QCD, using the non-perturbatively improved Sheikholeslami-Wohlert Wilson Fermionic action. We simulate n{sub F}=2 mass degenerate sea quarks with a pion mass of about 285 MeV and a lattice spacing {approx}0.073 fm. The renormalization of the matrix elements involves mixing between contributions from different quark flavours. The pion-nucleon {sigma}-term is extrapolated to physical quark masses exploiting the sea quark mass dependence of the nucleon mass. We obtain the renormalized values {sigma}{sub {pi}}{sub N}=(38{+-}12) MeV at the physical point and f{sub T{sub s}}={sigma}{sub s}/m{sub N}=0.012(14){sup +10}{sub -3} for the strangeness contribution at our larger than physical sea quark mass. (orig.)
Measurement of the strange quark contribution to the proton spin using neutral kaons at HERMES
International Nuclear Information System (INIS)
This thesis reports a new ''isoscalar'' measurement of Δs + Δ 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 Δs + Δ anti s only the spin asymmetry for K0s AK0s1,d (x,Q2, z) and the inclusive asymmetry A1,d(x,Q2) are used. An accurate measurement of the total non-strange quark polarisation ΔQ = Δu + Δ anti u + Δd + Δ anti d comes directly from A1,d(x,Q2). The fragmentation functions needed for a leading order (LO) extraction of ΔS = Δs + Δ 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.)
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.)
Strange mesons from quark and hadron matter a comparison
Biro, T S; Zimányi, J
2001-01-01
In a simplified model we study the hadronization of quark matter in an expanding fireball, in particular the approach to a final hadronic composition in equilibrium. Ideal hadron gas equilibrium constrained by conservation laws, the fugacity parametrization, as well as linear and non-linear coalescence approaches are recognized as different approximations to this in-medium quark fusion process. It is shown that color confinement requires a dependence of the hadronization cross section on quark density in the presence of flow (dynamical confinement).
Determination of strange sea quark distributions from fixed-target and collider data
International Nuclear Information System (INIS)
We present an improved determination of the strange sea distribution in the nucleon with constraints coming from the recent charm production data in neutrino-nucleon deep-inelastic scattering by the NOMAD and CHORUS experiments and from charged current inclusive deep-inelastic scattering at HERA. We demonstrate that the results are consistent with the data from the ATLAS and the CMS experiments on the associated production of W±-bosons with c-quarks. We also discuss issues related to the recent strange sea determination by the ATLAS experiment using LHC collider data.
International Nuclear Information System (INIS)
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-π0ντ) = (0.471 ± 0.064stat ± 0.021sys)%, B(τ- → K-π+π-ντ) = (0.415 ± 0.059stat ± 0.031sys)% 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: ms(mτ2) = (84 ± 14exp ± 6Vus ± 17theo) MeV. Evolving this result to customary scales yields ms(1 GeV2) = (111-35+26) MeV, ms(4 GeV2) = (82-25+19) MeV. (orig.)
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.)
Light hadrons from lattice QCD with light (u,d), strange and charm dynamical quarks
Baron, Remi; Carbonell, Jaume; Deuzeman, Albert; Drach, Vincent; Farchioni, Federico; Gimenez, Vicent; Herdoiza, Gregorio; Jansen, Karl; McNeile, Craig; Michael, Chris; Montvay, Istvan; Palao, David; Pallante, Elisabetta; Pene, Olivier; Reker, Siebren; Urbach, Carsten; Wagner, Marc; Wenger, Urs
2010-01-01
We present results of lattice QCD simulations with mass-degenerate up and down and mass-split strange and charm (N_f = 2+1+1) dynamical quarks using Wilson twisted mass fermions at maximal twist. The tuning of the strange and charm quark masses is performed at two values of the lattice spacing a~0.078 fm and a~0.086 fm with lattice sizes ranging from L~1.9 fm to L~2.8 fm. We measure with high statistical precision the light pseudoscalar mass m_PS and decay constant f_PS in a range 270 < m_PS < 510 MeV and determine the low energy parameters f_0, l_3 and l_4 of SU(2) chiral perturbation theory. We use the two values of the lattice spacing, several lattice sizes as well as different values of the light, strange and charm quark masses to explore the systematic effects. A first study of discretisation effects in light-quark observables and a comparison to N_f=2 results are performed.
Two Seismic Events with the Properties for the Passage of Strange Quark Matter Through the Earth
Anderson, D P; Teplitz, V L; Tibuleac, I M; Anderson, David P.; Herrin, Eugene T.; Teplitz, Vigdor L.; Tibuleac, Ileana M.
2002-01-01
In 1984 Witten [1] proposed that an extremely dense form of matter composed of up, down, and strange quarks may periodically strike the Earth and be detectable by the seismic signals generated from its passage. We investigated over 1 million seismic data reports sent to the U.S. Geological Survey in the years 1990-1993 that were not associated with traditional epicentral sources. It is among this set of unassociated station reports that we would expect to find events with epilinear sources should they exist. Such a source could result from the passage of a nugget of strange quark matter (SQM) through the Earth's mantle. Two sets of reports were found that fit the epilinear source model for arrival times, array pointing, and waveform characteristics, and do not fit an epicentral source model or multiple epicentral sources model. These two events have the properties predicted for the passage of an SQM nugget through the Earth.
Results from the forward G0 experiment. Strange quark contribution to the nucleon structure
International Nuclear Information System (INIS)
The G0 experiment is dedicated to the determination of the strange quark contribution to the electric and magnetic nucleon form factors for a large range of momentum transfers between 0.1 to 1 (GeV/c)2. This information is provided by the asymmetries of cross-sections measured with longitudinally polarized electrons in elastic electron-proton scattering and quasi-elastic electron-deuteron scattering. A set of measurements at two different Q2 will allow the complete separation of the electric and magnetic weak, as well as axial nucleon form factors. This report summarizes the physics case, gives details about the dedicated set-up used, and shows the results of the combination of the strange quark contribution in the electric and magnetic form factors of the protons. The experiment was performed at the Jefferson Laboratory, during years 2003 and 2004, and will be completed after backward-angle measurements in 2006, 2007. (orig.)
Excited bottom and bottom-strange mesons in the quark model
Lü, Qi-Fang; Wang, Yan-Yan; Wang, En; Li, De-Min
2016-01-01
In order to understand the possible $q\\bar{q}$ quark-model assignments of the $B_J(5840)$ and $B_J(5960)$ recently reported by the LHCb Collaboration, we evaluate mass spectra, strong decays, and radiative decays of bottom and bottom-strange mesons in a nonrelativistic quark model. Comparing these predictions with the relevant experimental results, we suggest that the $B_J(5840)$ and $B_J(5960)$ can be identified as $B(2^1S_0)$ and $B(1^3D_3)$, respectively, and the $B(5970)$ reported by the CDF Collaboration can be interpreted as $B(2^3S_1)$ or $B(1^3D_3)$. Further precise measurements of the width, spin and decay modes of the $B(5970)$ are needed to distinguish these two assignments. These predictions of bottom and bottom-strange mesons can provide useful information to further experimental investigations.
Lattice calculation of the leading strange quark-connected contribution to the muon $g-2$
Blum, T; Del Debbio, L; Hudspith, R J; Izubuchi, T; Jüttner, A; Lehner, C; Lewis, R; Maltman, K; Marinković, M Krstić; Portelli, A; Spraggs, M
2016-01-01
We present results for the leading hadronic contribution to the muon anomalous magnetic moment due to strange quark-connected vacuum polarisation effects. Simulations were performed using RBC--UKQCD's $N_f=2+1$ domain wall fermion ensembles with physical light sea quark masses at two lattice spacings. We consider a large number of analysis scenarios in order to obtain solid estimates for residual systematic effects. Our final result in the continuum limit is $a_\\mu^{(2)\\,{\\rm had},\\,s}=53.1(9)\\left(^{+1}_{-3}\\right)\\times10^{-10}$.
Color-flavor locked strange quark matter in a mass density-dependent model
International Nuclear Information System (INIS)
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)
Lattice calculation of the leading strange quark-connected contribution to the muon g - 2
Blum, T.; Boyle, P. A.; Del Debbio, L.; Hudspith, R. J.; Izubuchi, T.; Jüttner, A.; Lehner, C.; Lewis, R.; Maltman, K.; Krstić Marinković, M.; Portelli, A.; Spraggs, M.
2016-04-01
We present results for the leading hadronic contribution to the muon anomalous magnetic moment due to strange quark-connected vacuum polarisation effects. Simulations were performed using RBC-UKQCD's N f = 2 + 1 domain wall fermion ensembles with physical light sea quark masses at two lattice spacings. We consider a large number of analysis scenarios in order to obtain solid estimates for residual systematic effects. Our final result in the continuum limit is a μ (2)had, s = 53.1(9)( - 3 + 1 ) × 10- 10.
Reevaluation of the Parton Distribution of Strange Quarks in the Nucleon
Airapetian, A; Akopov, Z; Aschenauer, E C; Augustyniak, W; Avetissian, A; Avetisyan, E; Belostotski, S; Blok, H P; Borissov, A; Bryzgalov, V; Burns, J; Capiluppi, M; Capitani, G P; Cisbani, E; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; Deconinck, W; De Leo, R; De Sanctis, E; Diefenthaler, M; Di Nezza, P; Düren, M; Ehrenfried, M; Elbakian, G; Ellinghaus, F; Etzelmüller, E; Felawka, L; Frullani, S; Gabbert, D; Gapienko, G; Gapienko, V; García, J Garay; Garibaldi, F; Gavrilov, G; Gharibyan, V; Giordano, F; Gliske, S; Hartig, M; Hasch, D; Hoek, M; Holler, Y; Hristova, I; Jackson, H E; Joosten, S; Kaiser, R; Karyan, G; Keri, T; Kinney, E; Kisselev, A; Korotkov, V; Kozlov, V; Kravchenko, P; Krivokhijine, V G; Lagamba, L; Lapikás, L; Lehmann, I; Lenisa, P; Lorenzon, W; Ma, B -Q; Mahon, D; Manaenkov, S I; Mao, Y; Marianski, B; Marukyan, H; Miyachi, Y; Movsisyan, A; Muccifora, V; Murray, M; Mussgiller, A; Naryshkin, Y; Nass, A; Negodaev, M; Nowak, W -D; Pappalardo, L L; Perez-Benito, R; Petrosyan, A; Reimer, P E; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubin, J; Ryckbosch, D; Salomatin, Y; Schäfer, A; Schnell, G; Seitz, B; Shibata, T -A; Stahl, M; Statera, M; Steffens, E; Steijger, J J M; Stinzing, F; Taroian, S; Terkulov, A; Truty, R; Trzcinski, A; Tytgat, M; Van Haarlem, Y; Van Hulse, C; Veretennikov, D; Vikhrov, V; Vilardi, I; Vogel, C; Wang, S; Yaschenko, S; Ye, Z; Yen, S; Zihlmann, B; Zupranski, P
2013-01-01
An earlier extraction from the HERMES experiment of the polarization-averaged parton distribution of strange quarks in the nucleon has been reevaluated using final data on the multiplicities of charged kaons in semi-inclusive deep-inelastic scattering obtained with a kinematically more comprehensive method of correcting for experimental effects. General features of the distribution are confirmed, but the rise at low $x$ is less pronounced than previously reported.
Reevaluation of the parton distribution of strange quarks in the nucleon
Energy Technology Data Exchange (ETDEWEB)
Airapetian, A. [Giessen Univ. (Germany). II. Physikalisches Institut; Michigan Univ., Ann Arbor, MI (United States). Randall Laboratory of Physics; Akopov, N. [Yerevan Physics Institute (Argentina); Akopov, Z. [DESY Hamburg (Germany); Collaboration: HERMES Collaboration; and others
2013-12-15
An earlier extraction from the HERMES experiment of the polarization-averaged parton distribution of strange quarks in the nucleon has been reevaluated using final data on the multiplicities of charged kaons in semi-inclusive deep-inelastic scattering obtained with a kinematically more comprehensive method of correcting for experimental effects. General features of the distribution are confirmed, but the rise at low x is less pronounced than previously reported.
MEASUREMENT OF THE STRANGE QUARK CONTRIBUTION TO THE VECTOR STRUCTURE OF THE PROTON
Energy Technology Data Exchange (ETDEWEB)
Sarah Phillips
2007-11-30
The goal of the G0 experiment is to determine the contribution of the strange quarks in the quark-antiquark sea to the structure of the nucleon. To this end, the experiment measured parityviolating asymmetries from elastic electron-proton scattering from 0.12 ≤ Q2 ≤ 1.0 (GeV/c)2 at Thomas Jefferson National Accelerator Facility. These asymmetries come from the interference of the electromagnetic and neutral weak interactions, and are sensitive to the strange quark contributions in the proton. The results from the forward-angle measurement, the linear combination of the strange electric and magnetic form factors GsE +ηGsM, suggest possible non-zero, Q2 dependent, strange quark contributions and provide new information to understand the magnitude of the contributions. This dissertation presents the analysis and results of the forward-angle measurement. In addition, the G0 experiment measured the beam-normal single-spin asymmetry in the elastic scattering of transversely polarized 3 GeV electrons from unpolarized protons at Q2 = 0.15, 0.25 (GeV/c)2 as part of the forward-angle measurement. The transverse asymmetry provides a direct probe of the imaginary component of the two-photon exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments. The results of the measurement indicate that calculations using solely the elastic nucleon intermediate state are insufficient and generally agree with calculations that include significant inelastic hadronic intermediate state contributions. This dissertation presents the analysis and results of this measurement.
Strange quark matter attached to string cloud in general scalar tensor theory of gravitation
Directory of Open Access Journals (Sweden)
V U M Rao
2014-12-01
Full Text Available Bianchi type-VI0 space time with strange quark matter attached to string cloud in Nordtvedt [1] general scalar tensor theory of gravitation with the help of a special case proposed by Schwinger [2] is obtained. The field equations have been solved by using the anisotropy feature of the universe in the Bianchi type-VI0 space time. Some important features of the model, thus obtained, have been discussed
The strange quark mass and Lambda parameter of two flavor QCD
Energy Technology Data Exchange (ETDEWEB)
Fritzsch, Patrick; Marinkovic, Marina [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Knechtli, Francesco; Leder, Bjoern [Wuppertal Univ. (Germany). Fachbereich C - Mathematik und Naturwissenschaften; Schaefer, Stefan [CERN, Geneva (Switzerland). Physics Dept.; Sommer, Rainer; Virotta, Francesco [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2012-06-15
We complete the non-perturbative calculations of the strange quark mass and the {lambda} parameter in two flavor QCD by the ALPHA collaboration. The missing lattice scale is determined via the kaon decay constant, for whose chiral extrapolation complementary strategies are compared. We also give a value for the scale r{sub 0} in physical units as well as an improved determination of the renormalization constant Z{sub A}.
The strange quark mass and Lambda parameter of two flavor QCD
International Nuclear Information System (INIS)
We complete the non-perturbative calculations of the strange quark mass and the Λ parameter in two flavor QCD by the ALPHA collaboration. The missing lattice scale is determined via the kaon decay constant, for whose chiral extrapolation complementary strategies are compared. We also give a value for the scale r0 in physical units as well as an improved determination of the renormalization constant ZA.
Integrating out strange quarks in ChPT: Terms at order p6
International Nuclear Information System (INIS)
Chiral perturbation theory in the two-flavour sector allows one to analyse Green functions in QCD in a limit where the strange quark mass is considered to be large in comparison to the external momenta and to the light quark masses mu and md. In this framework, the low-energy constants of SU(2)RxSU(2)L depend on the value of the heavy quark masses. In a recent article, we have worked out, for the coupling constants li which occur at order p4 in the chiral expansion, the dependence on the strange quark mass at two-loop accuracy. Here, we provide analogous relations for some of the couplings ci which are relevant at order p6. To keep the calculations somewhat reasonable in size, we consider only those 28 couplings which enter the Green functions built from vector and axial vector quark currents in the chiral limit mu=md=0, ms≠0. This provides the matching for 27 linear combinations of the 28 couplings.
Lattice QCD with dynamical up, down and strange quarks
Energy Technology Data Exchange (ETDEWEB)
Schaefer, Stefan
2014-07-01
This project incorporates many new ingredients. Starting with the action which has been specifically tuned for the current effort, over the many algorithmic innovations to the newly formed group of researchers from all over Europe which are involved in these simulations. The project is currently underway, with the goal to generate lattices at three different values of the lattice spacing. The parameters are now tuned, the first ensembles have reached target statistics and the others under production. On these ensembles a large variety of physics projects will be carried out. The first targets being the determination of the strong coupling constant and the physics of charm quarks. The wide range of lattice spacings and quark masses and the availability of the lattices to the large group of reasearches within CLS will certainly lead to many interesting results in the next year, the ground for which are currently being laid during the current investigations. (orig.)
International Nuclear Information System (INIS)
Semi-inclusive spin asymmetries for positively and negatively charged hadrons measured in deep inelastic scattering of polarised muons on polarised protons and deuterons are presented. The x-dependent spin distributions for up and down valence quarks and for non-strange sea quarks are determined. (author)
Properties of strange quark matter objects with two types of surface treatments
Xia, Cheng-Jun; Peng, Guang-Xiong; Zhao, En-Guang; Zhou, Shan-Gui
2016-04-01
We study strange quark matter (SQM) objects ranging from strangelets to strange stars based on our recently proposed unified description. The important interface effects are investigated by adopting a constant surface tension as well as the multiple reflection expansion (MRE) method. It is shown that the properties of SQM objects are strongly affected by the different surface treatments. In the former case, strangelets are more compact, an electric dipole is predicted on the surface of the quark part, and a local minimum of the energy per baryon appears for unusually small values of the surface tension. In the latter case, on the other hand, an electric potential well is formed, and the energy per baryon decreases monotonically with the SQM object's size. It is found that the MRE scenario coincides with the constant-surface-tension one if realistic values are considered. However, the effects of quark depletion on the quark-vacuum interface cannot be solely described by a constant surface tension. Thus we conclude that the MRE scenario is more reasonable.
International Nuclear Information System (INIS)
We calculate the thermodynamic properties of strange quark matter by using the density and temperature dependent particle mass model of Wen et al. For the interaction Hamiltonian we use the one gluon exchange interaction obtained from the Fermi liquid picture. We let the QCD coupling (αc) be constant or vary with density and temperature. A new set of mass scalings for quarks is evaluated from the present interaction, which can be used with thermodynamic formulas derived by Wen et al. Similar to β-stable matter, no stability is found in strange quark matter. Finally, it is shown that the present equation of state of strange quark matter becomes harder with respect to that obtained using the string model, specially with non-constant QCD coupling. (author)
Estimating the unquenched strange quark mass from the lattice axial Ward identity
International Nuclear Information System (INIS)
We present a determination of the strange quark mass for two flavors (nf=2) of light dynamical quarks using the axial Ward identity. The calculations are performed on the lattice using O(a) improved Wilson fermions and include a fully nonperturbative determination of the renormalization constant. In the continuum limit we find msMS(2 GeV)=111(6)(4)(6) MeV, using the force scale r0=0.467 fm, where the first error is statistical, the second and third are systematic due to the fit and scale uncertainties, respectively. Results are also presented for the light quark mass and the chiral condensate. The corresponding results are also given for r0=0.5 fm
Estimating the unquenched strange quark mass from the lattice axial Ward identity
International Nuclear Information System (INIS)
We present a determination of the strange quark mass for two flavours (nf=2) of light dynamical quarks using the axial Ward identity. The calculations are performed on the lattice using O(a) improved Wilson fermions and include a fully non-perturbative determination of the renormalisation constant. In the continuum limit we find msMS (2 GeV)=111(6)(4)(6) MeV, using the force scale r0=0.467 fm, where the first error is statistical, the second and third are systematic due to the fit and scale uncertainties respectively. Results are also presented for the light quark mass and the chiral condensate. The corresponding results are also given for r0=0.5 fm. (orig.)
Quark Molecular Model of the S=0 Strange Pentaquark (u-sbar)-(uds) Baryon Spectrum
Williams, R A; Williams, Robert A.; Gueye, Paul
2003-01-01
We present a non-relativistic quark molecular model (QMM) of the strange crypto-exotic pentaquark baryon spectrum motivated by the recent data showing narrow, resonance enhancements in electromagnetic and hadronic production of kaons. Our model assumes color octet bonded quark molecular clusters forming exotic color singlet pentaquark baryons. We develop explicit molecular pentaquark wavefunctions that exhibit color interchange and cluster fermion antisymmetry. Our color electro-dynamics (CED) inspired Hamiltonian, which includes confinement, one gluon exchange and color magnetic interactions, is a natural generalization of the Isgur and Karl quark model Hamiltonian that reproduces the conventional meson (q-qbar) and baryon (qqq) spectrumWe introduce the idea of Color Magnetic Confinement (CMC) which is employed to restrict the physical pentaquark spectrum and constrain the fundamental constants (color gyromagnetic ratios) of the QMM-CED Hamiltonian. Comparing our QMM spectrum predictions with the recent expe...
International Nuclear Information System (INIS)
The G0 (G-Zero) forward angle experiment completed in Hall C of the Thomas Jefferson National Accelerator Facility (TJNAF) has measured the parity violating asymmetries in elastic electron-proton scattering over a Q2 range of 0.12 < Q2 < 1.0 (GeV/c)2. A linear combination of the strange electric (GsE) and magnetic (GsM) form factors calculated from these asymmetries indicate a non-zero contribution of the strange quark to the charge and magnetization structure of the proton in the above kinematic range at a 89% confidence level. The results show a previously unmeasured Q2 dependence of the strange form factors. Combining the G0 results with previous parity violating experiments show that at Q2 = 0.1 (GeV/c)2 GsM = 0.62+-0.31 GsE = -0.013+-0.028 At intermediate Q2 of about 0.23 (GeV/c)2, a consistent value of GsM is seen compared to previous experiments, together with a measurement that may imply a negative value of GsE. For Q2 above 0.5 (GeV/c)2 a consistently positive value for the linear combination of the strange form factors is seen
Up, down, strange and charm quark masses with Nf=2+1+1 twisted mass lattice QCD
International Nuclear Information System (INIS)
We present a lattice QCD calculation of the up, down, strange and charm quark masses performed using the gauge configurations produced by the European Twisted Mass Collaboration with Nf=2+1+1 dynamical quarks, which include in the sea, besides two light mass degenerate quarks, also the strange and charm quarks with masses close to their physical values. The simulations are based on a unitary setup for the two light quarks and on a mixed action approach for the strange and charm quarks. The analysis uses data at three values of the lattice spacing and pion masses in the range 210–450 MeV, allowing for accurate continuum limit and controlled chiral extrapolation. The quark mass renormalization is carried out non-perturbatively using the RI′-MOM method. The results for the quark masses converted to the MS¯ scheme are: mud(2 GeV)=3.70(17) MeV, ms(2 GeV)=99.6(4.3) MeV and mc(mc)=1.348(46) GeV. We obtain also the quark mass ratios ms/mud=26.66(32) and mc/ms=11.62(16). By studying the mass splitting between the neutral and charged kaons and using available lattice results for the electromagnetic contributions, we evaluate mu/md=0.470(56), leading to mu=2.36(24) MeV and md=5.03(26) MeV
Up, down, strange and charm quark masses with Nf=2+1+1 twisted mass lattice QCD
Directory of Open Access Journals (Sweden)
N. Carrasco
2014-10-01
Full Text Available We present a lattice QCD calculation of the up, down, strange and charm quark masses performed using the gauge configurations produced by the European Twisted Mass Collaboration with Nf=2+1+1 dynamical quarks, which include in the sea, besides two light mass degenerate quarks, also the strange and charm quarks with masses close to their physical values. The simulations are based on a unitary setup for the two light quarks and on a mixed action approach for the strange and charm quarks. The analysis uses data at three values of the lattice spacing and pion masses in the range 210–450 MeV, allowing for accurate continuum limit and controlled chiral extrapolation. The quark mass renormalization is carried out non-perturbatively using the RI′-MOM method. The results for the quark masses converted to the MS¯ scheme are: mud(2 GeV=3.70(17 MeV, ms(2 GeV=99.6(4.3 MeV and mc(mc=1.348(46 GeV. We obtain also the quark mass ratios ms/mud=26.66(32 and mc/ms=11.62(16. By studying the mass splitting between the neutral and charged kaons and using available lattice results for the electromagnetic contributions, we evaluate mu/md=0.470(56, leading to mu=2.36(24 MeV and md=5.03(26 MeV.
Up, down, strange and charm quark masses with Nf = 2+1+1 twisted mass lattice QCD
Carrasco, N; Dimopoulos, P; Frezzotti, R; Gimenez, V; Herdoiza, G; Lami, P; Lubicz, V; Palao, D; Picca, E; Recker, S; Riggio, L; Rossi, G C; Sanfilippo, F; Scorzato, L; Simula, S; Tarantino, C; Urbach, C; Wenger, U
2014-01-01
We present a lattice QCD calculation of the up, down, strange and charm quark masses performed using the gauge configurations produced by the European Twisted Mass Collaboration with Nf = 2 + 1 + 1 dynamical quarks, which include in the sea, besides two light mass degenerate quarks, also the strange and charm quarks with masses close to their physical values. The simulations are based on a unitary setup for the two light quarks and on a mixed action approach for the strange and charm quarks. The analysis uses data at three values of the lattice spacing and pion masses in the range 210 - 450 MeV, allowing for accurate continuum limit and controlled chiral extrapolation. The quark mass renormalization is carried out non-perturbatively using the RI-MOM method. The results for the quark masses converted to the bar{MS} scheme are: mud(2 GeV) = 3.70(17) MeV, ms(2 GeV) = 99.6(4.1) MeV and mc(mc) = 1.348(42) GeV. We obtain also the quark mass ratios ms/mud = 26.66(32) and mc/ms = 11.62(16). By studying the mass split...
Search for strange quark matter in high-energy heavy-ion collisions
International Nuclear Information System (INIS)
We have initiated a search for strange quark matter in the products of 14.6 GeV/c per nucleon 28Si collisions with nuclei, utilizing the apparatus of E-814 at Brookhaven National Laboratory's AGS. We report the first results of this search, which is sensitive to particles with charge-to-mass ratios between 0.1 and 0.3 (GeV/c2)-1 that are produced within approximately ±0.5 units of the center of mass rapidity. (orig.)
Lunar Seismic Detector to Advance the Search for Strange Quark Matter
Galitzki, Nicholas B.
2005-01-01
Detection of small seismic signals on the Moon are needed to study lunar internal structure and to detect possible signals from Strange Quark m&er transit events. The immediate objective is to create a prototype seismic detector using a tunnel diode oscillator with a variable capacitor attached to a proof mass. The device is designed to operate effectively on the Moon, which requires a low power consumption to operate through lunar night, while preserving sensitivity. The goal is capacitance resolution of better than 1 part in 10' and power consumption of less than 1 watt.
International Nuclear Information System (INIS)
We have measured parity-violating asymmetries in elastic electron-proton and quasielastic electron-deuteron scattering at Q2=0.22 and 0.63 GeV2. They are sensitive to strange quark contributions to currents in the nucleon and the nucleon axial-vector current. The results indicate strange quark contributions of < or approx. 10% of the charge and magnetic nucleon form factors at these four-momentum transfers. We also present the first measurement of anapole moment effects in the axial-vector current at these four-momentum transfers.
Energy Technology Data Exchange (ETDEWEB)
David Armstrong; Francois Arvieux; Razmik Asaturyan; Todd Averett; Stephanie Bailey; Guillaume Batigne; Douglas Beck; Elizabeth Beise; Jay Benesch; Louis Bimbot; James Birchall; Angela Biselli; Peter Bosted; Elodie Boukobza; Herbert Breuer; Roger Carlini; R. Carr; Nicholas Chant; Yu-Chiu Chao; Swapan Chattopadhyay; Russell Clark; Silviu Covrig; Anthony Cowley; Daniel Dale; C. Davis; Willie Falk; John Finn; Tony Forest; Gregg Franklin; Christophe Furget; David Gaskell; Joseph Grames; Keith Griffioen; Klaus Grimm; Benoit Guillon; Hayko Guler; Lars Hannelius; R. Hasty; A. Hawthorne Allen; Tanja Horn; Kathleen Johnston; Mark Jones; Peter Kammel; Reza Kazimi; Paul King; Ameya Kolarkar; Elie Korkmaz; Wolfgang Korsch; Serge Kox; Joachim Kuhn; Jeff Lachniet; Lawrence Lee; Jason Lenoble; Eric Liatard; J. Liu; Berenice Loupias; A. Lung; Glen MacLachlan; Dominique Marchand; J.W. Martin; Kenneth McFarlane; Daniella Mckee; Robert McKeown; Fernand Merchez; Hamlet Mkrtchyan; Bryan Moffit; M. Morlet; Itaru Nakagawa; Kazutaka Nakahara; Melissa Nakos; Retief Neveling; Silvia Niccolai; S. Ong; Shelley Page; Vassilios Papavassiliou; Stephen Pate; Sarah Phillips; Mark Pitt; Benard Poelker; Tracy Porcelli; Gilles Quemener; Brian Quinn; William Ramsay; Aamer Rauf; Jean-Sebastien Real; Julie Roche; Philip Roos; Gary Rutledge; Jeffery Secrest; Neven Simicevic; G.R. Smith; Damon Spayde; Samuel Stepanyan; Marcy Stutzman; Vincent Sulkosky; Vardan Tadevosyan; Raphael Tieulent; Jacques Van de Wiele; Willem van Oers; Eric Voutier; William Vulcan; G. Warren; S.P. Wells; Steven Williamson; S.A. Wood; Chen Yan; Junho Yun; Valdis Zeps
2005-06-01
We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < Q{sup 2} < 1.0 GeV{sup 2}. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange quark contributions to the currents of the proton. The measurements were made at JLab using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate non-zero, Q{sup 2} dependent, strange quark contributions and provide new information beyond that obtained in previous experiments.
Armstrong, D S; Asaturyan, R; Averett, T; Bailey, S L; Batigne, G; Beck, D H; Beise, E J; Benesch, J; Bimbot, L; Birchall, J; Biselli, A; Bosted, P; Boukobza, E; Breuer, H; Carlini, R; Carr, R; Chant, N; Chao Yu Chiu; Chattopadhyay, S; Clark, R; Covrig, S D; Cowley, A; Dale, D; Davis, C; Falk, W; Finn, J M; Forest, T; Franklin, G; Furget, C; Gaskell, D; Grames, J; Griffioen, K A; Grimm, K; Guillon, B; Guler, H; Hannelius, L; Hasty, R; Hawthorne Allen, A; Horn, T; Johnston, K; Jones, M; Kammel, P; Kazimi, R; King, P M; Kolarkar, A; Korkmaz, E; Korsch, W; Kox, S; Kühn, J; Lachniet, J; Lee, L; Lenoble, J; Liatard, E; Liu, J; Loupias, B; Lung, A; MacLachlan, G A; Marchand, D; Martin, J W; McFarlane, K W; McKee, D W; McKeown, R D; Merchez, F; Mkrtchyan, H G; Moffit, B; Morlet, M; Nakagawa, I; Nakahara, K; Nakos, M; Neveling, R; Niccolai, S; Ong, S; Page, S; Papavassiliou, V; Pate, S F; Phillips, S K; Pitt, M L; Poelker, M; Porcelli, T A; Quéméner, G; Quinn, B; Ramsay, W D; Rauf, A W; Real, J S; Roche, J; Roos, P; Rutledge, G A; Secrest, J; Simicevic, N; Smith, G R; Spayde, D T; Stepanyan, S; Stutzman, M; Sulkosky, V; Tadevosyan, V; Tieulent, R; Van der Wiele, J; Van Oers, W T H; Voutier, E; Vulcan, W; Warren, G; Wells, S P; Williamson, S E; Wood, S A; Yan, C; Yun, J; Zeps, V
2005-01-01
We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < Q^2 < 1.0 GeV^2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange quark contributions to the currents of the proton. The measurements were made at JLab using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate non-zero, Q^2 dependent, strange quark contributions and provide new information beyond that obtained in previous experiments.
Lattice simulations with $N_f=2+1$ improved Wilson fermions at a fixed strange quark mass
Bali, Gunnar S; Simeth, Jakob; Söldner, Wolfgang
2016-01-01
The explicit breaking of chiral symmetry of the Wilson fermion action results in additive quark mass renormalization. Moreover, flavour singlet and non-singlet scalar currents acquire different renormalization constants with respect to continuum regularization schemes. This complicates keeping the renormalized strange quark mass fixed when varying the light quark mass in simulations with $N_f=2+1$ sea quark flavours. Here we present and validate our strategy within the CLS (Coordinated Lattice Simulations) effort to achieve this in simulations with non-perturbatively order-$a$ improved Wilson fermions. We also determine various combinations of renormalization constants and improvement coefficients.
Charm-strange baryon strong decays in a chiral quark model
Liu, Lei-Hua; Zhong, Xian-Hui
2012-01-01
The strong decays of charm-strange baryons up to N=2 shell are studied in a chiral quark model. The theoretical predictions for the well determined charm-strange baryons, $\\Xi_c^*(2645)$, $\\Xi_c(2790)$ and $\\Xi_c(2815)$, are in good agreement with the experimental data. This model is also extended to analyze the strong decays of the other newly observed charm-strange baryons $\\Xi_c(2930)$, $\\Xi_c(2980)$, $\\Xi_c(3055)$, $\\Xi_c(3080)$ and $\\Xi_c(3123)$. Our predictions are given as follows. (i) $\\Xi_c(2930)$ might be the first $P$-wave excitation of $\\Xi_c'$ with $J^P=1/2^-$, favors the $|\\Xi_c'\\ ^2P_\\lambda 1/2^->$ or $|\\Xi_c'\\ ^4P_\\lambda 1/2^->$ state. (ii) $\\Xi_c(2980)$ might correspond to two overlapping $P$-wave states $|\\Xi_c'\\ ^2P_\\rho 1/2^->$ and $|\\Xi_c'\\ ^2P_\\rho 3/2^->$, respectively. The $\\Xi_c(2980)$ observed in the $\\Lambda_c^+\\bar{K}\\pi$ final state is most likely to be the $|\\Xi_c'\\ ^2P_\\rho 1/2^->$ state, while the narrower resonance with a mass $m\\simeq 2.97$ GeV observed in the $\\Xi_c^*(2645...
Fast spinning strange stars: possible ways to constrain interacting quark matter parameters
Bhattacharyya, Sudip; Logoteta, Domenico; Thampan, Arun V
2016-01-01
For a set of equation of state (EoS) models involving interacting strange quark matter, characterized by an effective bag constant (B_eff) and a perturbative QCD corrections term (a_4), we construct fully general relativistic equilibrium sequences of rapidly spinning strange stars for the first time. Computation of such sequences is important to study millisecond pulsars and other fast spinning compact stars. Our EoS models can support a gravitational mass (M_G) and a spin frequency at least up to approximately 3.0 solar mass and approximately 1250 Hz respectively, and hence are fully consistent with measured M_G and spin frequency values. This paper reports the effects of B_eff and a_4 on measurable compact star properties, which could be useful to find possible ways to constrain these fundamental quark matter parameters, within the ambit of our EoS models. We confirm that a lower B_eff allows a higher mass. Besides, for known M_G and spin frequency, measurable parameters, such as stellar radius, radius-to-m...
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.
Up, down, strange and charm quark masses with N{sub f}=2+1+1 twisted mass lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Carrasco, N. [INFN, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146 Rome (Italy); Deuzeman, A. [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland); Dimopoulos, P. [Centro Fermi – Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Compendio del Viminale, Piazza del Viminale 1, I-00184 Rome (Italy); Dipartimento di Fisica, Università di Roma “Tor Vergata”, Via della Ricerca Scientifica 1, I-00133 Rome (Italy); Frezzotti, R. [Dipartimento di Fisica, Università di Roma “Tor Vergata”, Via della Ricerca Scientifica 1, I-00133 Rome (Italy); INFN, Sezione di “Tor Vergata”, Via della Ricerca Scientifica 1, I-00133 Rome (Italy); Giménez, V. [Departament de Física Teòrica and IFIC, Univ. de València – CSIC, Dr. Moliner 50, E-46100 València (Spain); Herdoiza, G. [PRISMA Cluster of Excellence, Institut für Kernphysik, Johannes Gutenberg-Universität, D-55099 Mainz (Germany); Lami, P.; Lubicz, V. [Dipartimento di Matematica e Fisica, Università Roma Tre, Via della Vasca Navale 84, I-00146 Rome (Italy); INFN, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146 Rome (Italy); Palao, D. [Goethe-Universität, Institut für Theoretische Physik, Max-von-Laue-Straße 1, D-60438 Frankfurt am Main (Germany); and others
2014-10-15
We present a lattice QCD calculation of the up, down, strange and charm quark masses performed using the gauge configurations produced by the European Twisted Mass Collaboration with N{sub f}=2+1+1 dynamical quarks, which include in the sea, besides two light mass degenerate quarks, also the strange and charm quarks with masses close to their physical values. The simulations are based on a unitary setup for the two light quarks and on a mixed action approach for the strange and charm quarks. The analysis uses data at three values of the lattice spacing and pion masses in the range 210–450 MeV, allowing for accurate continuum limit and controlled chiral extrapolation. The quark mass renormalization is carried out non-perturbatively using the RI′-MOM method. The results for the quark masses converted to the MS{sup ¯} scheme are: m{sub ud}(2 GeV)=3.70(17) MeV, m{sub s}(2 GeV)=99.6(4.3) MeV and m{sub c}(m{sub c})=1.348(46) GeV. We obtain also the quark mass ratios m{sub s}/m{sub ud}=26.66(32) and m{sub c}/m{sub s}=11.62(16). By studying the mass splitting between the neutral and charged kaons and using available lattice results for the electromagnetic contributions, we evaluate m{sub u}/m{sub d}=0.470(56), leading to m{sub u}=2.36(24) MeV and m{sub d}=5.03(26) MeV.
Determination of the strange quark density of the proton from ATLAS measurements of the $W \\to l\
Aad, Georges; Abdallah, Jalal; Abdelalim, Ahmed Ali; Abdesselam, Abdelouahab; Abdinov, Ovsat; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Acerbi, Emilio; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Addy, Tetteh; Adelman, Jahred; Aderholz, Michael; Adomeit, Stefanie; Adragna, Paolo; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; Aharrouche, Mohamed; Ahlen, Steven; Ahles, Florian; Ahmad, Ashfaq; Ahsan, Mahsana; Aielli, Giulio; Akdogan, Taylan; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Akiyama, Kunihiro; Alam, Mohammad; Alam, Muhammad Aftab; Albert, Justin; Albrand, Solveig; Aleksa, Martin; Aleksandrov, Igor; Alessandria, Franco; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Aliev, Malik; Alimonti, Gianluca; Alison, John; Aliyev, Magsud; Allbrooke, Benedict; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alon, Raz; Alonso, Alejandro; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amaral, Pedro; Amelung, Christoph; Ammosov, Vladimir; Amorim, Antonio; Amorós, Gabriel; Amram, Nir; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Andrieux, Marie-Laure; Anduaga, Xabier; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoun, Sahar; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Arce, Ayana; Arfaoui, Samir; Arguin, Jean-Francois; Arik, Engin; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnault, Christian; Artamonov, Andrei; Artoni, Giacomo; Arutinov, David; Asai, Shoji; Asfandiyarov, Ruslan; Ask, Stefan; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astbury, Alan; Astvatsatourov, Anatoli; Aubert, Bernard; Auge, Etienne; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Avramidou, Rachel Maria; Axen, David; Ay, Cano; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baccaglioni, Giuseppe; Bacci, Cesare; Bach, Andre; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Badescu, Elisabeta; Bagnaia, Paolo; Bahinipati, Seema; Bai, Yu; Bailey, David; Bain, Travis; Baines, John; Baker, Oliver Keith; Baker, Mark; Baker, Sarah; Banas, Elzbieta; Banerjee, Piyali; Banerjee, Swagato; Banfi, Danilo; Bangert, Andrea Michelle; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barashkou, Andrei; Barbaro Galtieri, Angela; Barber, Tom; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Bardin, Dmitri; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Barrillon, Pierre; Bartoldus, Rainer; Barton, Adam Edward; Bartsch, Valeria; Bates, Richard; Batkova, Lucia; Batley, Richard; Battaglia, Andreas; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beale, Steven; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Sebastian; Beckingham, Matthew; Becks, Karl-Heinz; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Begel, Michael; Behar Harpaz, Silvia; Behera, Prafulla; Beimforde, Michael; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellina, Francesco; Bellomo, Massimiliano; Belloni, Alberto; Beloborodova, Olga; Belotskiy, Konstantin; Beltramello, Olga; Ben Ami, Sagi; Benary, Odette; Benchekroun, Driss; Benchouk, Chafik; Bendel, Markus; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Benoit, Mathieu; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Berglund, Elina; Beringer, Jürg; Bernat, Pauline; Bernhard, Ralf; Bernius, Catrin; Berry, Tracey; Bertella, Claudia; Bertin, Antonio; Bertinelli, Francesco; Bertolucci, Federico; Besana, Maria Ilaria; Besson, Nathalie; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biesiada, Jed; Biglietti, Michela; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Biscarat, Catherine; Bitenc, Urban; Black, Kevin; Blair, Robert; Blanchard, Jean-Baptiste; Blanchot, Georges; Blazek, Tomas; Blocker, Craig; Blocki, Jacek; Blondel, Alain; Blum, Walter; Blumenschein, Ulrike; Bobbink, Gerjan; Bobrovnikov, Victor; Bocchetta, Simona Serena; Bocci, Andrea; Boddy, Christopher Richard; Boehler, Michael; Boek, Jennifer; Boelaert, Nele; Bogaerts, Joannes Andreas; Bogdanchikov, Alexander; Bogouch, Andrei; Bohm, Christian; Boisvert, Veronique; Bold, Tomasz; Boldea, Venera; Bolnet, Nayanka Myriam; Bona, Marcella; Bondarenko, Valery; Bondioli, Mario; Boonekamp, Maarten; Booth, Chris; Bordoni, Stefania; Borer, Claudia; Borisov, Anatoly; Borissov, Guennadi; Borjanovic, Iris; Borri, Marcello; Borroni, Sara; Bortolotto, Valerio; Bos, Kors; Boscherini, Davide; Bosman, Martine; Boterenbrood, Hendrik; Botterill, David; Bouchami, Jihene; Boudreau, Joseph; Bouhova-Thacker, Evelina Vassileva; Boumediene, Djamel Eddine; Bourdarios, Claire; Bousson, Nicolas; Boveia, Antonio; Boyd, James; Boyko, Igor; Bozhko, Nikolay; Bozovic-Jelisavcic, Ivanka; Bracinik, Juraj; Braem, André; Branchini, Paolo; Brandenburg, George; Brandt, Andrew; Brandt, Gerhard; Brandt, Oleg; Bratzler, Uwe; Brau, Benjamin; Brau, James; Braun, Helmut; Brelier, Bertrand; Bremer, Johan; Brenner, Richard; Bressler, Shikma; Britton, Dave; Brochu, Frederic; Brock, Ian; Brock, Raymond; Brodbeck, Timothy; Brodet, Eyal; Broggi, Francesco; Bromberg, Carl; Bronner, Johanna; Brooijmans, Gustaaf; Brooks, William; Brown, Gareth; Brown, Heather; Bruckman de Renstrom, Pawel; Bruncko, Dusan; Bruneliere, Renaud; Brunet, Sylvie; Bruni, Alessia; Bruni, Graziano; Bruschi, Marco; Buanes, Trygve; Buat, Quentin; Bucci, Francesca; Buchanan, James; Buchanan, Norman; Buchholz, Peter; Buckingham, Ryan; Buckley, Andrew; Buda, Stelian Ioan; Budagov, Ioulian; Budick, Burton; Büscher, Volker; Bugge, Lars; Bulekov, Oleg; Bunse, Moritz; Buran, Torleiv; Burckhart, Helfried; Burdin, Sergey; Burgess, Thomas; Burke, Stephen; Busato, Emmanuel; Bussey, Peter; Buszello, Claus-Peter; Butin, François; Butler, Bart; Butler, John; Buttar, Craig; Butterworth, Jonathan; Buttinger, William; Cabrera Urbán, Susana; Caforio, Davide; Cakir, Orhan; Calafiura, Paolo; Calderini, Giovanni; Calfayan, Philippe; Calkins, Robert; Caloba, Luiz; Caloi, Rita; Calvet, David; Calvet, Samuel; Camacho Toro, Reina; Camarri, Paolo; Cambiaghi, Mario; Cameron, David; Caminada, Lea Michaela; Campana, Simone; Campanelli, Mario; Canale, Vincenzo; Canelli, Florencia; Canepa, Anadi; Cantero, Josu; Capasso, Luciano; Capeans Garrido, Maria Del Mar; Caprini, Irinel; Caprini, Mihai; Capriotti, Daniele; Capua, Marcella; Caputo, Regina; Caramarcu, Costin; Cardarelli, Roberto; Carli, Tancredi; Carlino, Gianpaolo; Carminati, Leonardo; Caron, Bryan; Caron, Sascha; Carrillo Montoya, German D; Carter, Antony; Carter, Janet; Carvalho, João; Casadei, Diego; Casado, Maria Pilar; Cascella, Michele; Caso, Carlo; Castaneda Hernandez, Alfredo Martin; Castaneda-Miranda, Elizabeth; Castillo Gimenez, Victoria; Castro, Nuno Filipe; Cataldi, Gabriella; Cataneo, Fernando; Catinaccio, Andrea; Catmore, James; Cattai, Ariella; Cattani, Giordano; Caughron, Seth; Cauz, Diego; Cavalleri, Pietro; Cavalli, Donatella; Cavalli-Sforza, Matteo; Cavasinni, Vincenzo; Ceradini, Filippo; Cerqueira, Augusto Santiago; Cerri, Alessandro; Cerrito, Lucio; Cerutti, Fabio; Cetin, Serkant Ali; Cevenini, Francesco; Chafaq, Aziz; Chakraborty, Dhiman; Chan, Kevin; Chapleau, Bertrand; Chapman, John Derek; Chapman, John Wehrley; Chareyre, Eve; Charlton, Dave; Chavda, Vikash; Chavez Barajas, Carlos Alberto; Cheatham, Susan; Chekanov, Sergei; Chekulaev, Sergey; Chelkov, Gueorgui; Chelstowska, Magda Anna; Chen, Chunhui; Chen, Hucheng; Chen, Shenjian; Chen, Tingyang; Chen, Xin; Cheng, Shaochen; Cheplakov, Alexander; Chepurnov, Vladimir; Cherkaoui El Moursli, Rajaa; Chernyatin, Valeriy; Cheu, Elliott; Cheung, Sing-Leung; Chevalier, Laurent; Chiefari, Giovanni; Chikovani, Leila; Childers, John Taylor; Chilingarov, Alexandre; Chiodini, Gabriele; Chisholm, Andrew; Chizhov, Mihail; Choudalakis, Georgios; Chouridou, Sofia; Christidi, Illectra-Athanasia; Christov, Asen; Chromek-Burckhart, Doris; Chu, Ming-Lee; Chudoba, Jiri; Ciapetti, Guido; Ciba, Krzysztof; Ciftci, Abbas Kenan; Ciftci, Rena; Cinca, Diane; Cindro, Vladimir; Ciobotaru, Matei Dan; Ciocca, Claudia; Ciocio, Alessandra; Cirilli, Manuela; Citterio, Mauro; Ciubancan, Mihai; Clark, Allan G; Clark, Philip James; Cleland, Bill; Clemens, Jean-Claude; Clement, Benoit; Clement, Christophe; Clifft, Roger; Coadou, Yann; Cobal, Marina; Coccaro, Andrea; Cochran, James H; Coe, Paul; Cogan, Joshua Godfrey; Coggeshall, James; Cogneras, Eric; Colas, Jacques; Colijn, Auke-Pieter; Collins, Neil; Collins-Tooth, Christopher; Collot, Johann; Colon, German; Conde Muiño, Patricia; Coniavitis, Elias; Conidi, Maria Chiara; Consonni, Michele; Consorti, Valerio; Constantinescu, Serban; Conta, Claudio; Conventi, Francesco; Cook, James; Cooke, Mark; Cooper, Ben; Cooper-Sarkar, Amanda; Copic, Katherine; Cornelissen, Thijs; Corradi, Massimo; Corriveau, Francois; Cortes-Gonzalez, Arely; Cortiana, Giorgio; Costa, Giuseppe; Costa, María José; Costanzo, Davide; Costin, Tudor; Côté, David; Coura Torres, Rodrigo; Courneyea, Lorraine; Cowan, Glen; Cowden, Christopher; Cox, Brian; Cranmer, Kyle; Crescioli, Francesco; Cristinziani, Markus; Crosetti, Giovanni; Crupi, Roberto; Crépé-Renaudin, Sabine; Cuciuc, Constantin-Mihai; Cuenca Almenar, Cristóbal; Cuhadar Donszelmann, Tulay; Curatolo, Maria; Curtis, Chris; Cuthbert, Cameron; Cwetanski, Peter; Czirr, Hendrik; Czodrowski, Patrick; Czyczula, Zofia; D'Auria, Saverio; D'Onofrio, Monica; D'Orazio, Alessia; Da Silva, Paulo Vitor; Da Via, Cinzia; Dabrowski, Wladyslaw; Dai, Tiesheng; Dallapiccola, Carlo; Dam, Mogens; Dameri, Mauro; Damiani, Daniel; Danielsson, Hans Olof; Dannheim, Dominik; Dao, Valerio; Darbo, Giovanni; Darlea, Georgiana Lavinia; Davey, Will; Davidek, Tomas; Davidson, Nadia; Davidson, Ruth; Davies, Eleanor; Davies, Merlin; Davison, Adam; Davygora, Yuriy; Dawe, Edmund; Dawson, Ian; Dawson, John; Daya-Ishmukhametova, Rozmin; De, Kaushik; de Asmundis, Riccardo; De Castro, Stefano; De Castro Faria Salgado, Pedro; De Cecco, Sandro; de Graat, Julien; De Groot, Nicolo; de Jong, Paul; De La Taille, Christophe; De la Torre, Hector; De Lotto, Barbara; de Mora, Lee; De Nooij, Lucie; De Pedis, Daniele; De Salvo, Alessandro; De Sanctis, Umberto; De Santo, Antonella; De Vivie De Regie, Jean-Baptiste; Dean, Simon; Dearnaley, William James; Debbe, Ramiro; Debenedetti, Chiara; Dedovich, Dmitri; Degenhardt, James; Dehchar, Mohamed; Del Papa, Carlo; Del Peso, Jose; Del Prete, Tarcisio; Delemontex, Thomas; Deliyergiyev, Maksym; Dell'Acqua, Andrea; Dell'Asta, Lidia; Della Pietra, Massimo; della Volpe, Domenico; Delmastro, Marco; Delruelle, Nicolas; Delsart, Pierre-Antoine; Deluca, Carolina; Demers, Sarah; Demichev, Mikhail; Demirkoz, Bilge; Deng, Jianrong; Denisov, Sergey; Derendarz, Dominik; Derkaoui, Jamal Eddine; Derue, Frederic; Dervan, Paul; Desch, Klaus Kurt; Devetak, Erik; Deviveiros, Pier-Olivier; Dewhurst, Alastair; DeWilde, Burton; Dhaliwal, Saminder; Dhullipudi, Ramasudhakar; Di Ciaccio, Anna; Di Ciaccio, Lucia; Di Girolamo, Alessandro; Di Girolamo, Beniamino; Di Luise, Silvestro; Di Mattia, Alessandro; Di Micco, Biagio; Di Nardo, Roberto; Di Simone, Andrea; Di Sipio, Riccardo; Diaz, Marco Aurelio; Diblen, Faruk; Diehl, Edward; Dietrich, Janet; Dietzsch, Thorsten; Diglio, Sara; Dindar Yagci, Kamile; Dingfelder, Jochen; Dionisi, Carlo; Dita, Petre; Dita, Sanda; Dittus, Fridolin; Djama, Fares; Djobava, Tamar; do Vale, Maria Aline Barros; Do Valle Wemans, André; Doan, Thi Kieu Oanh; Dobbs, Matt; Dobinson, Robert; Dobos, Daniel; Dobson, Ellie; Dodd, Jeremy; Doglioni, Caterina; Doherty, Tom; Doi, Yoshikuni; Dolejsi, Jiri; Dolenc, Irena; Dolezal, Zdenek; Dolgoshein, Boris; Dohmae, Takeshi; Donadelli, Marisilvia; Donega, Mauro; Donini, Julien; Dopke, Jens; Doria, Alessandra; Dos Anjos, Andre; Dosil, Mireia; Dotti, Andrea; Dova, Maria-Teresa; Dowell, John; Doxiadis, Alexander; Doyle, Tony; Drasal, Zbynek; Drees, Jürgen; Dressnandt, Nandor; Drevermann, Hans; Driouichi, Chafik; Dris, Manolis; Dubbert, Jörg; Dube, Sourabh; Duchovni, Ehud; Duckeck, Guenter; Dudarev, Alexey; Dudziak, Fanny; Dührssen, Michael; Duerdoth, Ian; Duflot, Laurent; Dufour, Marc-Andre; Dunford, Monica; Duran Yildiz, Hatice; Duxfield, Robert; Dwuznik, Michal; Dydak, Friedrich; Düren, Michael; Ebenstein, William; Ebke, Johannes; Eckweiler, Sebastian; Edmonds, Keith; Edwards, Clive; Edwards, Nicholas Charles; Ehrenfeld, Wolfgang; Ehrich, Thies; Eifert, Till; Eigen, Gerald; Einsweiler, Kevin; Eisenhandler, Eric; Ekelof, Tord; El Kacimi, Mohamed; Ellert, Mattias; Elles, Sabine; Ellinghaus, Frank; Ellis, Katherine; Ellis, Nicolas; Elmsheuser, Johannes; Elsing, Markus; Emeliyanov, Dmitry; Engelmann, Roderich; Engl, Albert; Epp, Brigitte; Eppig, Andrew; Erdmann, Johannes; Ereditato, Antonio; Eriksson, Daniel; Ernst, Jesse; Ernst, Michael; Ernwein, Jean; Errede, Deborah; Errede, Steven; Ertel, Eugen; Escalier, Marc; Escobar, Carlos; Espinal Curull, Xavier; Esposito, Bellisario; Etienne, Francois; Etienvre, Anne-Isabelle; Etzion, Erez; Evangelakou, Despoina; Evans, Hal; Fabbri, Laura; Fabre, Caroline; Fakhrutdinov, Rinat; Falciano, Speranza; Fang, Yaquan; Fanti, Marcello; Farbin, Amir; Farilla, Addolorata; Farley, Jason; Farooque, Trisha; Farrington, Sinead; Farthouat, Philippe; Fassnacht, Patrick; Fassouliotis, Dimitrios; Fatholahzadeh, Baharak; Favareto, Andrea; Fayard, Louis; Fazio, Salvatore; Febbraro, Renato; Federic, Pavol; Fedin, Oleg; Fedorko, Woiciech; Fehling-Kaschek, Mirjam; Feligioni, Lorenzo; Fellmann, Denis; Feng, Cunfeng; Feng, Eric; Fenyuk, Alexander; Ferencei, Jozef; Ferland, Jonathan; Fernando, Waruna; Ferrag, Samir; Ferrando, James; Ferrara, Valentina; Ferrari, Arnaud; Ferrari, Pamela; Ferrari, Roberto; Ferreira de Lima, Danilo Enoque; Ferrer, Antonio; Ferrer, Maria Lorenza; Ferrere, Didier; Ferretti, Claudio; Ferretto Parodi, Andrea; Fiascaris, Maria; Fiedler, Frank; Filipčič, Andrej; Filippas, Anastasios; Filthaut, Frank; Fincke-Keeler, Margret; Fiolhais, Miguel; Fiorini, Luca; Firan, Ana; Fischer, Gordon; Fischer, Peter; Fisher, Matthew; Flechl, Martin; Fleck, Ivor; Fleckner, Johanna; Fleischmann, Philipp; Fleischmann, Sebastian; Flick, Tobias; Floderus, Anders; Flores Castillo, Luis; Flowerdew, Michael; Fokitis, Manolis; Fonseca Martin, Teresa; Forbush, David Alan; Formica, Andrea; Forti, Alessandra; Fortin, Dominique; Foster, Joe; Fournier, Daniel; Foussat, Arnaud; Fowler, Andrew; Fowler, Ken; Fox, Harald; Francavilla, Paolo; Franchino, Silvia; Francis, David; Frank, Tal; Franklin, Melissa; Franz, Sebastien; Fraternali, Marco; Fratina, Sasa; French, Sky; Friedrich, Felix; Froeschl, Robert; Froidevaux, Daniel; Frost, James; Fukunaga, Chikara; Fullana Torregrosa, Esteban; Fuster, Juan; Gabaldon, Carolina; Gabizon, Ofir; Gadfort, Thomas; Gadomski, Szymon; Gagliardi, Guido; Gagnon, Pauline; Galea, Cristina; Gallas, Elizabeth; Gallo, Valentina Santina; Gallop, Bruce; Gallus, Petr; Gan, KK; Gao, Yongsheng; Gapienko, Vladimir; Gaponenko, Andrei; Garberson, Ford; Garcia-Sciveres, Maurice; García, Carmen; García Navarro, José Enrique; Gardner, Robert; Garelli, Nicoletta; Garitaonandia, Hegoi; Garonne, Vincent; Garvey, John; Gatti, Claudio; Gaudio, Gabriella; Gaur, Bakul; Gauthier, Lea; Gavrilenko, Igor; Gay, Colin; Gaycken, Goetz; Gayde, Jean-Christophe; Gazis, Evangelos; Ge, Peng; Gee, Norman; Geerts, Daniël Alphonsus Adrianus; Geich-Gimbel, Christoph; Gellerstedt, Karl; Gemme, Claudia; Gemmell, Alistair; Genest, Marie-Hélène; Gentile, Simonetta; George, Matthias; George, Simon; Gerlach, Peter; Gershon, Avi; Geweniger, Christoph; Ghazlane, Hamid; Ghodbane, Nabil; Giacobbe, Benedetto; Giagu, Stefano; Giakoumopoulou, Victoria; Giangiobbe, Vincent; Gianotti, Fabiola; Gibbard, Bruce; Gibson, Adam; Gibson, Stephen; Gilbert, Laura; Gilewsky, Valentin; Gillberg, Dag; Gillman, Tony; Gingrich, Douglas; Ginzburg, Jonatan; Giokaris, Nikos; Giordani, MarioPaolo; Giordano, Raffaele; Giorgi, Francesco Michelangelo; Giovannini, Paola; Giraud, Pierre-Francois; Giugni, Danilo; Giunta, Michele; Giusti, Paolo; Gjelsten, Børge Kile; Gladilin, Leonid; Glasman, Claudia; Glatzer, Julian; Glazov, Alexandre; Glitza, Karl-Walter; Glonti, George; Goddard, Jack Robert; Godfrey, Jennifer; Godlewski, Jan; Goebel, Martin; Göpfert, Thomas; Goeringer, Christian; Gössling, Claus; Göttfert, Tobias; Goldfarb, Steven; Golling, Tobias; Gomes, Agostinho; Gomez Fajardo, Luz Stella; Gonçalo, Ricardo; Goncalves Pinto Firmino Da Costa, Joao; Gonella, Laura; Gonidec, Allain; Gonzalez, Saul; González de la Hoz, Santiago; Gonzalez Parra, Garoe; Gonzalez Silva, Laura; Gonzalez-Sevilla, Sergio; Goodson, Jeremiah Jet; Goossens, Luc; Gorbounov, Petr Andreevich; Gordon, Howard; Gorelov, Igor; Gorfine, Grant; Gorini, Benedetto; Gorini, Edoardo; Gorišek, Andrej; Gornicki, Edward; Gorokhov, Serguei; Goryachev, Vladimir; Gosdzik, Bjoern; Gosselink, Martijn; Gostkin, Mikhail Ivanovitch; Gough Eschrich, Ivo; Gouighri, Mohamed; Goujdami, Driss; Goulette, Marc Phillippe; Goussiou, Anna; Goy, Corinne; Gozpinar, Serdar; Grabowska-Bold, Iwona; Grafström, Per; Grahn, Karl-Johan; Grancagnolo, Francesco; Grancagnolo, Sergio; Grassi, Valerio; Gratchev, Vadim; Grau, Nathan; Gray, Heather; Gray, Julia Ann; Graziani, Enrico; Grebenyuk, Oleg; Greenshaw, Timothy; Greenwood, Zeno Dixon; Gregersen, Kristian; Gregor, Ingrid-Maria; Grenier, Philippe; Griffiths, Justin; Grigalashvili, Nugzar; Grillo, Alexander; Grinstein, Sebastian; Grishkevich, Yaroslav; Grivaz, Jean-Francois; Groh, Manfred; Gross, Eilam; Grosse-Knetter, Joern; Groth-Jensen, Jacob; Grybel, Kai; Guarino, Victor; Guest, Daniel; Guicheney, Christophe; Guida, Angelo; Guindon, Stefan; Guler, Hulya; Gunther, Jaroslav; Guo, Bin; Guo, Jun; Gupta, Ambreesh; Gusakov, Yury; Gushchin, Vladimir; Gutierrez, Phillip; Guttman, Nir; Gutzwiller, Olivier; Guyot, Claude; Gwenlan, Claire; Gwilliam, Carl; Haas, Andy; Haas, Stefan; Haber, Carl; Hadavand, Haleh Khani; Hadley, David; Haefner, Petra; Hahn, Ferdinand; Haider, Stefan; Hajduk, Zbigniew; Hakobyan, Hrachya; Hall, David; Haller, Johannes; Hamacher, Klaus; Hamal, Petr; Hamer, Matthias; Hamilton, Andrew; Hamilton, Samuel; Han, Hongguang; Han, Liang; Hanagaki, Kazunori; Hanawa, Keita; Hance, Michael; Handel, Carsten; Hanke, Paul; Hansen, John Renner; Hansen, Jørgen Beck; Hansen, Jorn Dines; Hansen, Peter Henrik; Hansson, Per; Hara, Kazuhiko; Hare, Gabriel; Harenberg, Torsten; Harkusha, Siarhei; Harper, Devin; Harrington, Robert; Harris, Orin; Harrison, Karl; Hartert, Jochen; Hartjes, Fred; Haruyama, Tomiyoshi; Harvey, Alex; Hasegawa, Satoshi; Hasegawa, Yoji; Hassani, Samira; Hatch, Mark; Hauff, Dieter; Haug, Sigve; Hauschild, Michael; Hauser, Reiner; Havranek, Miroslav; Hawes, Brian; Hawkes, Christopher; Hawkings, Richard John; Hawkins, Anthony David; Hawkins, Donovan; Hayakawa, Takashi; Hayashi, Takayasu; Hayden, Daniel; Hayward, Helen; Haywood, Stephen; Hazen, Eric; He, Mao; Head, Simon; Hedberg, Vincent; Heelan, Louise; Heim, Sarah; Heinemann, Beate; Heisterkamp, Simon; Helary, Louis; Heller, Claudio; Heller, Matthieu; Hellman, Sten; Hellmich, Dennis; Helsens, Clement; Henderson, Robert; Henke, Michael; Henrichs, Anna; Henriques Correia, Ana Maria; Henrot-Versille, Sophie; Henry-Couannier, Frédéric; Hensel, Carsten; Henß, Tobias; Hernandez, Carlos Medina; Hernández Jiménez, Yesenia; Herrberg, Ruth; Hershenhorn, Alon David; Herten, Gregor; Hertenberger, Ralf; Hervas, Luis; Hesketh, Gavin Grant; Hessey, Nigel; Higón-Rodriguez, Emilio; Hill, Daniel; Hill, John; Hill, Norman; Hiller, Karl Heinz; Hillert, Sonja; Hillier, Stephen; Hinchliffe, Ian; Hines, Elizabeth; Hirose, Minoru; Hirsch, Florian; Hirschbuehl, Dominic; Hobbs, John; Hod, Noam; Hodgkinson, Mark; Hodgson, Paul; Hoecker, Andreas; Hoeferkamp, Martin; Hoffman, Julia; Hoffmann, Dirk; Hohlfeld, Marc; Holder, Martin; Holmgren, Sven-Olof; Holy, Tomas; Holzbauer, Jenny; Homma, Yasuhiro; Hong, Tae Min; Hooft van Huysduynen, Loek; Horazdovsky, Tomas; Horn, Claus; Horner, Stephan; Hostachy, Jean-Yves; Hou, Suen; Houlden, Michael; Hoummada, Abdeslam; Howarth, James; Howell, David; Hristova, Ivana; Hrivnac, Julius; Hruska, Ivan; Hryn'ova, Tetiana; Hsu, Pai-hsien Jennifer; Hsu, Shih-Chieh; Huang, Guang Shun; Hubacek, Zdenek; Hubaut, Fabrice; Huegging, Fabian; Huettmann, Antje; Huffman, Todd Brian; Hughes, Emlyn; Hughes, Gareth; Hughes-Jones, Richard; Huhtinen, Mika; Hurst, Peter; Hurwitz, Martina; Husemann, Ulrich; Huseynov, Nazim; Huston, Joey; Huth, John; Iacobucci, Giuseppe; Iakovidis, Georgios; Ibbotson, Michael; Ibragimov, Iskander; Ichimiya, Ryo; Iconomidou-Fayard, Lydia; Idarraga, John; Iengo, Paolo; Igonkina, Olga; Ikegami, Yoichi; Ikeno, Masahiro; Ilchenko, Yuri; Iliadis, Dimitrios; Ilic, Nikolina; Imori, Masatoshi; Ince, Tayfun; Inigo-Golfin, Joaquin; Ioannou, Pavlos; Iodice, Mauro; Ippolito, Valerio; Irles Quiles, Adrian; Isaksson, Charlie; Ishikawa, Akimasa; Ishino, Masaya; Ishmukhametov, Renat; Issever, Cigdem; Istin, Serhat; Ivashin, Anton; Iwanski, Wieslaw; Iwasaki, Hiroyuki; Izen, Joseph; Izzo, Vincenzo; Jackson, Brett; Jackson, John; Jackson, Paul; Jaekel, Martin; Jain, Vivek; Jakobs, Karl; Jakobsen, Sune; Jakubek, Jan; Jana, Dilip; Jankowski, Ernest; Jansen, Eric; Jansen, Hendrik; Jantsch, Andreas; Janus, Michel; Jarlskog, Göran; Jeanty, Laura; Jelen, Kazimierz; Jen-La Plante, Imai; Jenni, Peter; Jeremie, Andrea; Jež, Pavel; Jézéquel, Stéphane; Jha, Manoj Kumar; Ji, Haoshuang; Ji, Weina; Jia, Jiangyong; Jiang, Yi; Jimenez Belenguer, Marcos; Jin, Ge; Jin, Shan; Jinnouchi, Osamu; Joergensen, Morten Dam; Joffe, David; Johansen, Lars; Johansen, Marianne; Johansson, Erik; Johansson, Per; Johnert, Sebastian; Johns, Kenneth; Jon-And, Kerstin; Jones, Graham; Jones, Roger; Jones, Tegid; Jones, Tim; Jonsson, Ove; Joram, Christian; Jorge, Pedro; Joseph, John; Jovicevic, Jelena; Jovin, Tatjana; Ju, Xiangyang; Jung, Christian; Jungst, Ralph Markus; Juranek, Vojtech; Jussel, Patrick; Juste Rozas, Aurelio; Kabachenko, Vasily; Kabana, Sonja; Kaci, Mohammed; Kaczmarska, Anna; Kadlecik, Peter; Kado, Marumi; Kagan, Harris; Kagan, Michael; Kaiser, Steffen; Kajomovitz, Enrique; Kalinin, Sergey; Kalinovskaya, Lidia; Kama, Sami; Kanaya, Naoko; Kaneda, Michiru; Kaneti, Steven; Kanno, Takayuki; Kantserov, Vadim; Kanzaki, Junichi; Kaplan, Benjamin; Kapliy, Anton; Kaplon, Jan; Kar, Deepak; Karagounis, Michael; Karagoz, Muge; Karnevskiy, Mikhail; Karr, Kristo; Kartvelishvili, Vakhtang; Karyukhin, Andrey; Kashif, Lashkar; Kasieczka, Gregor; Kass, Richard; Kastanas, Alex; Kataoka, Mayuko; Kataoka, Yousuke; Katsoufis, Elias; Katzy, Judith; Kaushik, Venkatesh; Kawagoe, Kiyotomo; Kawamoto, Tatsuo; Kawamura, Gen; Kayl, Manuel; Kazanin, Vassili; Kazarinov, Makhail; Keeler, Richard; Kehoe, Robert; Keil, Markus; Kekelidze, George; Kennedy, John; Kenney, Christopher John; Kenyon, Mike; Kepka, Oldrich; Kerschen, Nicolas; Kerševan, Borut Paul; Kersten, Susanne; Kessoku, Kohei; Keung, Justin; Khalil-zada, Farkhad; Khandanyan, Hovhannes; Khanov, Alexander; Kharchenko, Dmitri; Khodinov, Alexander; Kholodenko, Anatoli; Khomich, Andrei; Khoo, Teng Jian; Khoriauli, Gia; Khoroshilov, Andrey; Khovanskiy, Nikolai; Khovanskiy, Valery; Khramov, Evgeniy; Khubua, Jemal; Kim, Hyeon Jin; Kim, Min Suk; Kim, Shinhong; Kimura, Naoki; Kind, Oliver; King, Barry; King, Matthew; King, Robert Steven Beaufoy; Kirk, Julie; Kirsch, Lawrence; Kiryunin, Andrey; Kishimoto, Tomoe; Kisielewska, Danuta; Kittelmann, Thomas; Kiver, Andrey; Kladiva, Eduard; Klaiber-Lodewigs, Jonas; Klein, Max; Klein, Uta; Kleinknecht, Konrad; Klemetti, Miika; Klier, Amit; Klimek, Pawel; Klimentov, Alexei; Klingenberg, Reiner; Klinger, Joel Alexander; Klinkby, Esben; Klioutchnikova, Tatiana; Klok, Peter; Klous, Sander; Kluge, Eike-Erik; Kluge, Thomas; Kluit, Peter; Kluth, Stefan; Knecht, Neil; Kneringer, Emmerich; Knobloch, Juergen; Knoops, Edith; Knue, Andrea; Ko, Byeong Rok; Kobayashi, Tomio; Kobel, Michael; Kocian, Martin; Kodys, Peter; Köneke, Karsten; König, Adriaan; Koenig, Sebastian; Köpke, Lutz; Koetsveld, Folkert; Koevesarki, Peter; Koffas, Thomas; Koffeman, Els; Kogan, Lucy Anne; Kohn, Fabian; Kohout, Zdenek; Kohriki, Takashi; Koi, Tatsumi; Kokott, Thomas; Kolachev, Guennady; Kolanoski, Hermann; Kolesnikov, Vladimir; Koletsou, Iro; Koll, James; Kollefrath, Michael; Kolya, Scott; Komar, Aston; Komori, Yuto; Kondo, Takahiko; Kono, Takanori; Kononov, Anatoly; Konoplich, Rostislav; Konstantinidis, Nikolaos; Kootz, Andreas; Koperny, Stefan; Korcyl, Krzysztof; Kordas, Kostantinos; Koreshev, Victor; Korn, Andreas; Korol, Aleksandr; Korolkov, Ilya; Korolkova, Elena; Korotkov, Vladislav; Kortner, Oliver; Kortner, Sandra; Kostyukhin, Vadim; Kotamäki, Miikka Juhani; Kotov, Sergey; Kotov, Vladislav; Kotwal, Ashutosh; Kourkoumelis, Christine; Kouskoura, Vasiliki; Koutsman, Alex; Kowalewski, Robert Victor; Kowalski, Tadeusz; Kozanecki, Witold; Kozhin, Anatoly; Kral, Vlastimil; Kramarenko, Viktor; Kramberger, Gregor; Krasny, Mieczyslaw Witold; Krasznahorkay, Attila; Kraus, James; Kraus, Jana; Kreisel, Arik; Krejci, Frantisek; Kretzschmar, Jan; Krieger, Nina; Krieger, Peter; Kroeninger, Kevin; Kroha, Hubert; Kroll, Joe; Kroseberg, Juergen; Krstic, Jelena; Kruchonak, Uladzimir; Krüger, Hans; Kruker, Tobias; Krumnack, Nils; Krumshteyn, Zinovii; Kruth, Andre; Kubota, Takashi; Kuday, Sinan; Kuehn, Susanne; Kugel, Andreas; Kuhl, Thorsten; Kuhn, Dietmar; Kukhtin, Victor; Kulchitsky, Yuri; Kuleshov, Sergey; Kummer, Christian; Kuna, Marine; Kundu, Nikhil; Kunkle, Joshua; Kupco, Alexander; Kurashige, Hisaya; Kurata, Masakazu; Kurochkin, Yurii; Kus, Vlastimil; Kuwertz, Emma Sian; Kuze, Masahiro; Kvita, Jiri; Kwee, Regina; La Rosa, Alessandro; La Rotonda, Laura; Labarga, Luis; Labbe, Julien; Lablak, Said; Lacasta, Carlos; Lacava, Francesco; Lacker, Heiko; Lacour, Didier; Lacuesta, Vicente Ramón; Ladygin, Evgueni; Lafaye, Remi; Laforge, Bertrand; Lagouri, Theodota; Lai, Stanley; Laisne, Emmanuel; Lamanna, Massimo; Lampen, Caleb; Lampl, Walter; Lancon, Eric; Landgraf, Ulrich; Landon, Murrough; Lane, Jenna; Lange, Clemens; Lankford, Andrew; Lanni, Francesco; Lantzsch, Kerstin; Laplace, Sandrine; Lapoire, Cecile; Laporte, Jean-Francois; Lari, Tommaso; Larionov, Anatoly; Larner, Aimee; Lasseur, Christian; Lassnig, Mario; Laurelli, Paolo; Lavorini, Vincenzo; Lavrijsen, Wim; Laycock, Paul; Lazarev, Alexandre; Le Dortz, Olivier; Le Guirriec, Emmanuel; Le Maner, Christophe; Le Menedeu, Eve; Lebel, Céline; LeCompte, Thomas; Ledroit-Guillon, Fabienne Agnes Marie; Lee, Hurng-Chun; Lee, Jason; Lee, Shih-Chang; Lee, Lawrence; Lefebvre, Michel; Legendre, Marie; Leger, Annie; LeGeyt, Benjamin; Legger, Federica; Leggett, Charles; Lehmacher, Marc; Lehmann Miotto, Giovanna; Lei, Xiaowen; Leite, Marco Aurelio Lisboa; Leitner, Rupert; Lellouch, Daniel; Leltchouk, Mikhail; Lemmer, Boris; Lendermann, Victor; Leney, Katharine; Lenz, Tatiana; Lenzen, Georg; Lenzi, Bruno; Leonhardt, Kathrin; Leontsinis, Stefanos; Leroy, Claude; Lessard, Jean-Raphael; Lesser, Jonas; Lester, Christopher; Leung Fook Cheong, Annabelle; Levêque, Jessica; Levin, Daniel; Levinson, Lorne; Levitski, Mikhail; Lewis, Adrian; Lewis, George; Leyko, Agnieszka; Leyton, Michael; Li, Bo; Li, Haifeng; Li, Shu; Li, Xuefei; Liang, Zhijun; Liao, Hongbo; Liberti, Barbara; Lichard, Peter; Lichtnecker, Markus; Lie, Ki; Liebig, Wolfgang; Lifshitz, Ronen; Limbach, Christian; Limosani, Antonio; Limper, Maaike; Lin, Simon; Linde, Frank; Linnemann, James; Lipeles, Elliot; Lipinsky, Lukas; Lipniacka, Anna; Liss, Tony; Lissauer, David; Lister, Alison; Litke, Alan; Liu, Chuanlei; Liu, Dong; Liu, Hao; Liu, Jianbei; Liu, Minghui; Liu, Yanwen; Livan, Michele; Livermore, Sarah; Lleres, Annick; Llorente Merino, Javier; Lloyd, Stephen; Lobodzinska, Ewelina; Loch, Peter; Lockman, William; Loddenkoetter, Thomas; Loebinger, Fred; Loginov, Andrey; Loh, Chang Wei; Lohse, Thomas; Lohwasser, Kristin; Lokajicek, Milos; Loken, James; Lombardo, Vincenzo Paolo; Long, Robin Eamonn; Lopes, Lourenco; Lopez Mateos, David; Lorenz, Jeanette; Lorenzo Martinez, Narei; Losada, Marta; Loscutoff, Peter; Lo Sterzo, Francesco; Losty, Michael; Lou, Xinchou; Lounis, Abdenour; Loureiro, Karina; Love, Jeremy; Love, Peter; Lowe, Andrew; Lu, Feng; Lubatti, Henry; Luci, Claudio; Lucotte, Arnaud; Ludwig, Andreas; Ludwig, Dörthe; Ludwig, Inga; Ludwig, Jens; Luehring, Frederick; Luijckx, Guy; Lumb, Debra; Luminari, Lamberto; Lund, Esben; Lund-Jensen, Bengt; Lundberg, Björn; Lundberg, Johan; Lundquist, Johan; Lungwitz, Matthias; Lutz, Gerhard; Lynn, David; Lys, Jeremy; Lytken, Else; Ma, Hong; Ma, Lian Liang; Macana Goia, Jorge Andres; Maccarrone, Giovanni; Macchiolo, Anna; Maček, Boštjan; Machado Miguens, Joana; Mackeprang, Rasmus; Madaras, Ronald; Mader, Wolfgang; Maenner, Reinhard; Maeno, Tadashi; Mättig, Peter; Mättig, Stefan; Magnoni, Luca; Magradze, Erekle; Mahalalel, Yair; Mahboubi, Kambiz; Mahout, Gilles; Maiani, Camilla; Maidantchik, Carmen; Maio, Amélia; Majewski, Stephanie; Makida, Yasuhiro; Makovec, Nikola; Mal, Prolay; Malaescu, Bogdan; Malecki, Pawel; Malecki, Piotr; Maleev, Victor; Malek, Fairouz; Mallik, Usha; Malon, David; Malone, Caitlin; Maltezos, Stavros; Malyshev, Vladimir; Malyukov, Sergei; Mameghani, Raphael; Mamuzic, Judita; Manabe, Atsushi; Mandelli, Luciano; Mandić, Igor; Mandrysch, Rocco; Maneira, José; Mangeard, Pierre-Simon; Manhaes de Andrade Filho, Luciano; Manjavidze, Ioseb; Mann, Alexander; Manning, Peter; Manousakis-Katsikakis, Arkadios; Mansoulie, Bruno; Manz, Andreas; Mapelli, Alessandro; Mapelli, Livio; March, Luis; Marchand, Jean-Francois; Marchese, Fabrizio; Marchiori, Giovanni; Marcisovsky, Michal; Marino, Christopher; Marroquim, Fernando; Marshall, Robin; Marshall, Zach; Martens, Kalen; Marti-Garcia, Salvador; Martin, Andrew; Martin, Brian; Martin, Brian; Martin, Franck Francois; Martin, Jean-Pierre; Martin, Philippe; Martin, Tim; Martin, Victoria Jane; Martin dit Latour, Bertrand; Martin-Haugh, Stewart; Martinez, Mario; Martinez Outschoorn, Verena; Martyniuk, Alex; Marx, Marilyn; Marzano, Francesco; Marzin, Antoine; Masetti, Lucia; Mashimo, Tetsuro; Mashinistov, Ruslan; Masik, Jiri; Maslennikov, Alexey; Massa, Ignazio; Massaro, Graziano; Massol, Nicolas; Mastrandrea, Paolo; Mastroberardino, Anna; Masubuchi, Tatsuya; Matricon, Pierre; Matsumoto, Hiroshi; Matsunaga, Hiroyuki; Matsushita, Takashi; Mattravers, Carly; Maugain, Jean-Marie; Maurer, Julien; Maxfield, Stephen; Maximov, Dmitriy; May, Edward; Mayne, Anna; Mazini, Rachid; Mazur, Michael; Mazzanti, Marcello; Mc Kee, Shawn Patrick; McCarn, Allison; McCarthy, Robert; McCarthy, Tom; McCubbin, Norman; McFarlane, Kenneth; Mcfayden, Josh; McGlone, Helen; Mchedlidze, Gvantsa; McLaren, Robert Andrew; Mclaughlan, Tom; McMahon, Steve; McPherson, Robert; Meade, Andrew; Mechnich, Joerg; Mechtel, Markus; Medinnis, Mike; Meera-Lebbai, Razzak; Meguro, Tatsuma; Mehdiyev, Rashid; Mehlhase, Sascha; Mehta, Andrew; Meier, Karlheinz; Meirose, Bernhard; Melachrinos, Constantinos; Mellado Garcia, Bruce Rafael; Mendoza Navas, Luis; Meng, Zhaoxia; Mengarelli, Alberto; Menke, Sven; Menot, Claude; Meoni, Evelin; Mercurio, Kevin Michael; Mermod, Philippe; Merola, Leonardo; Meroni, Chiara; Merritt, Frank; Merritt, Hayes; Messina, Andrea; Metcalfe, Jessica; Mete, Alaettin Serhan; Meyer, Carsten; Meyer, Christopher; Meyer, Jean-Pierre; Meyer, Jochen; Meyer, Joerg; Meyer, Thomas Christian; Meyer, W Thomas; Miao, Jiayuan; Michal, Sebastien; Micu, Liliana; Middleton, Robin; Migas, Sylwia; Mijović, Liza; Mikenberg, Giora; Mikestikova, Marcela; Mikuž, Marko; Miller, David; Miller, Robert; Mills, Bill; Mills, Corrinne; Milov, Alexander; Milstead, David; Milstein, Dmitry; Minaenko, Andrey; Miñano Moya, Mercedes; Minashvili, Irakli; Mincer, Allen; Mindur, Bartosz; Mineev, Mikhail; Ming, Yao; Mir, Lluisa-Maria; Mirabelli, Giovanni; Miralles Verge, Lluis; Misiejuk, Andrzej; Mitrevski, Jovan; Mitrofanov, Gennady; Mitsou, Vasiliki A; Mitsui, Shingo; Miyagawa, Paul; Miyazaki, Kazuki; Mjörnmark, Jan-Ulf; Moa, Torbjoern; Mockett, Paul; Moed, Shulamit; Moeller, Victoria; Mönig, Klaus; Möser, Nicolas; Mohapatra, Soumya; Mohr, Wolfgang; Mohrdieck-Möck, Susanne; Moisseev, Artemy; Moles-Valls, Regina; Molina-Perez, Jorge; Monk, James; Monnier, Emmanuel; Montesano, Simone; Monticelli, Fernando; Monzani, Simone; Moore, Roger; Moorhead, Gareth; Mora Herrera, Clemencia; Moraes, Arthur; Morange, Nicolas; Morel, Julien; Morello, Gianfranco; Moreno, Deywis; Moreno Llácer, María; Morettini, Paolo; Morgenstern, Marcus; Morii, Masahiro; Morin, Jerome; Morley, Anthony Keith; Mornacchi, Giuseppe; Morozov, Sergey; Morris, John; Morvaj, Ljiljana; Moser, Hans-Guenther; Mosidze, Maia; Moss, Josh; Mount, Richard; Mountricha, Eleni; Mouraviev, Sergei; Moyse, Edward; Mudrinic, Mihajlo; Mueller, Felix; Mueller, James; Mueller, Klemens; Müller, Thomas; Mueller, Timo; Muenstermann, Daniel; Muir, Alex; Munwes, Yonathan; Murray, Bill; Mussche, Ido; Musto, Elisa; Myagkov, Alexey; Myska, Miroslav; Nadal, Jordi; Nagai, Koichi; Nagano, Kunihiro; Nagarkar, Advait; Nagasaka, Yasushi; Nagel, Martin; Nairz, Armin Michael; Nakahama, Yu; Nakamura, Koji; Nakamura, Tomoaki; Nakano, Itsuo; Nanava, Gizo; Napier, Austin; Narayan, Rohin; Nash, Michael; Nation, Nigel; Nattermann, Till; Naumann, Thomas; Navarro, Gabriela; Neal, Homer; Nebot, Eduardo; Nechaeva, Polina; Neep, Thomas James; Negri, Andrea; Negri, Guido; Nektarijevic, Snezana; Nelson, Andrew; Nelson, Silke; Nelson, Timothy Knight; Nemecek, Stanislav; Nemethy, Peter; Nepomuceno, Andre Asevedo; Nessi, Marzio; Neubauer, Mark; Neusiedl, Andrea; Neves, Ricardo; Nevski, Pavel; Newman, Paul; Nguyen Thi Hong, Van; Nickerson, Richard; Nicolaidou, Rosy; Nicolas, Ludovic; Nicquevert, Bertrand; Niedercorn, Francois; Nielsen, Jason; Niinikoski, Tapio; Nikiforou, Nikiforos; Nikiforov, Andriy; Nikolaenko, Vladimir; Nikolaev, Kirill; Nikolic-Audit, Irena; Nikolics, Katalin; Nikolopoulos, Konstantinos; Nilsen, Henrik; Nilsson, Paul; Ninomiya, Yoichi; Nisati, Aleandro; Nishiyama, Tomonori; Nisius, Richard; Nodulman, Lawrence; Nomachi, Masaharu; Nomidis, Ioannis; Nordberg, Markus; Nordkvist, Bjoern; Norton, Peter; Novakova, Jana; Nozaki, Mitsuaki; Nozka, Libor; Nugent, Ian Michael; Nuncio-Quiroz, Adriana-Elizabeth; Nunes Hanninger, Guilherme; Nunnemann, Thomas; Nurse, Emily; O'Brien, Brendan Joseph; O'Neale, Steve; O'Neil, Dugan; O'Shea, Val; Oakes, Louise Beth; Oakham, Gerald; Oberlack, Horst; Ocariz, Jose; Ochi, Atsuhiko; Oda, Susumu; Odaka, Shigeru; Odier, Jerome; Ogren, Harold; Oh, Alexander; Oh, Seog; Ohm, Christian; Ohshima, Takayoshi; Ohshita, Hidetoshi; Ohsugi, Takashi; Okada, Shogo; Okawa, Hideki; Okumura, Yasuyuki; Okuyama, Toyonobu; Olariu, Albert; Olcese, Marco; Olchevski, Alexander; Olivares Pino, Sebastian Andres; Oliveira, Miguel Alfonso; Oliveira Damazio, Denis; Oliver Garcia, Elena; Olivito, Dominick; Olszewski, Andrzej; Olszowska, Jolanta; Omachi, Chihiro; Onofre, António; Onyisi, Peter; Oram, Christopher; Oreglia, Mark; Oren, Yona; Orestano, Domizia; Orlov, Iliya; Oropeza Barrera, Cristina; Orr, Robert; Osculati, Bianca; Ospanov, Rustem; Osuna, Carlos; Otero y Garzon, Gustavo; Ottersbach, John; Ouchrif, Mohamed; Ouellette, Eric; Ould-Saada, Farid; Ouraou, Ahmimed; Ouyang, Qun; Ovcharova, Ana; Owen, Mark; Owen, Simon; Ozcan, Veysi Erkcan; Ozturk, Nurcan; Pacheco Pages, Andres; Padilla Aranda, Cristobal; Pagan Griso, Simone; Paganis, Efstathios; Paige, Frank; Pais, Preema; Pajchel, Katarina; Palacino, Gabriel; Paleari, Chiara; Palestini, Sandro; Pallin, Dominique; Palma, Alberto; Palmer, Jody; Pan, Yibin; Panagiotopoulou, Evgenia; Panes, Boris; Panikashvili, Natalia; Panitkin, Sergey; Pantea, Dan; Panuskova, Monika; Paolone, Vittorio; Papadelis, Aras; Papadopoulou, Theodora; Paramonov, Alexander; Paredes Hernandez, Daniela; Park, Woochun; Parker, Andy; Parodi, Fabrizio; Parsons, John; Parzefall, Ulrich; Pasqualucci, Enrico; Passaggio, Stefano; Passeri, Antonio; Pastore, Fernanda; Pastore, Francesca; Pásztor, Gabriella; Pataraia, Sophio; Patel, Nikhul; Pater, Joleen; Patricelli, Sergio; Pauly, Thilo; Pecsy, Martin; Pedraza Morales, Maria Isabel; Peleganchuk, Sergey; Peng, Haiping; Pengo, Ruggero; Penning, Bjoern; Penson, Alexander; Penwell, John; Perantoni, Marcelo; Perez, Kerstin; Perez Cavalcanti, Tiago; Perez Codina, Estel; Pérez García-Estañ, María Teresa; Perez Reale, Valeria; Perini, Laura; Pernegger, Heinz; Perrino, Roberto; Perrodo, Pascal; Persembe, Seda; Perus, Antoine; Peshekhonov, Vladimir; Peters, Krisztian; Petersen, Brian; Petersen, Jorgen; Petersen, Troels; Petit, Elisabeth; Petridis, Andreas; Petridou, Chariclia; Petrolo, Emilio; Petrucci, Fabrizio; Petschull, Dennis; Petteni, Michele; Pezoa, Raquel; Phan, Anna; Phillips, Peter William; Piacquadio, Giacinto; Picazio, Attilio; Piccaro, Elisa; Piccinini, Maurizio; Piec, Sebastian Marcin; Piegaia, Ricardo; Pignotti, David; Pilcher, James; Pilkington, Andrew; Pina, João Antonio; Pinamonti, Michele; Pinder, Alex; Pinfold, James; Ping, Jialun; Pinto, Belmiro; Pirotte, Olivier; Pizio, Caterina; Plamondon, Mathieu; Pleier, Marc-Andre; Pleskach, Anatoly; Poblaguev, Andrei; Poddar, Sahill; Podlyski, Fabrice; Poggioli, Luc; Poghosyan, Tatevik; Pohl, Martin; Polci, Francesco; Polesello, Giacomo; Policicchio, Antonio; Polini, Alessandro; Poll, James; Polychronakos, Venetios; Pomarede, Daniel Marc; Pomeroy, Daniel; Pommès, Kathy; Pontecorvo, Ludovico; Pope, Bernard; Popeneciu, Gabriel Alexandru; Popovic, Dragan; Poppleton, Alan; Portell Bueso, Xavier; Posch, Christoph; Pospelov, Guennady; Pospisil, Stanislav; Potrap, Igor; Potter, Christina; Potter, Christopher; Poulard, Gilbert; Poveda, Joaquin; Pozdnyakov, Valery; Prabhu, Robindra; Pralavorio, Pascal; Pranko, Aliaksandr; Prasad, Srivas; Pravahan, Rishiraj; Prell, Soeren; Pretzl, Klaus Peter; Pribyl, Lukas; Price, Darren; Price, Joe; Price, Lawrence; Price, Michael John; Prieur, Damien; Primavera, Margherita; Prokofiev, Kirill; Prokoshin, Fedor; Protopopescu, Serban; Proudfoot, James; Prudent, Xavier; Przybycien, Mariusz; Przysiezniak, Helenka; Psoroulas, Serena; Ptacek, Elizabeth; Pueschel, Elisa; Purdham, John; Purohit, Milind; Puzo, Patrick; Pylypchenko, Yuriy; Qian, Jianming; Qian, Zuxuan; Qin, Zhonghua; Quadt, Arnulf; Quarrie, David; Quayle, William; Quinonez, Fernando; Raas, Marcel; Radescu, Voica; Radics, Balint; Radloff, Peter; Rador, Tonguc; Ragusa, Francesco; Rahal, Ghita; Rahimi, Amir; Rahm, David; Rajagopalan, Srinivasan; Rammensee, Michael; Rammes, Marcus; Randle-Conde, Aidan Sean; Randrianarivony, Koloina; Ratoff, Peter; Rauscher, Felix; Rave, Tobias Christian; Raymond, Michel; Read, Alexander Lincoln; Rebuzzi, Daniela; Redelbach, Andreas; Redlinger, George; Reece, Ryan; Reeves, Kendall; Reichold, Armin; Reinherz-Aronis, Erez; Reinsch, Andreas; Reisinger, Ingo; Rembser, Christoph; Ren, Zhongliang; Renaud, Adrien; Rescigno, Marco; Resconi, Silvia; Resende, Bernardo; Reznicek, Pavel; Rezvani, Reyhaneh; Richards, Alexander; Richter, Robert; Richter-Was, Elzbieta; Ridel, Melissa; Rijpstra, Manouk; Rijssenbeek, Michael; Rimoldi, Adele; Rinaldi, Lorenzo; Rios, Ryan Randy; Riu, Imma; Rivoltella, Giancesare; Rizatdinova, Flera; Rizvi, Eram; Robertson, Steven; Robichaud-Veronneau, Andree; Robinson, Dave; Robinson, James; Robson, Aidan; Rocha de Lima, Jose Guilherme; Roda, Chiara; Roda Dos Santos, Denis; Rodriguez, Diego; Roe, Adam; Roe, Shaun; Røhne, Ole; Rojo, Victoria; Rolli, Simona; Romaniouk, Anatoli; Romano, Marino; Romanov, Victor; Romeo, Gaston; Romero Adam, Elena; Roos, Lydia; Ros, Eduardo; Rosati, Stefano; Rosbach, Kilian; Rose, Anthony; Rose, Matthew; Rosenbaum, Gabriel; Rosenberg, Eli; Rosendahl, Peter Lundgaard; Rosenthal, Oliver; Rosselet, Laurent; Rossetti, Valerio; Rossi, Elvira; Rossi, Leonardo Paolo; Rotaru, Marina; Roth, Itamar; Rothberg, Joseph; Rousseau, David; Royon, Christophe; Rozanov, Alexander; Rozen, Yoram; Ruan, Xifeng; Rubinskiy, Igor; Ruckert, Benjamin; Ruckstuhl, Nicole; Rud, Viacheslav; Rudolph, Christian; Rudolph, Gerald; Rühr, Frederik; Ruggieri, Federico; Ruiz-Martinez, Aranzazu; Rumiantsev, Viktor; Rumyantsev, Leonid; Runge, Kay; Rurikova, Zuzana; Rusakovich, Nikolai; Rutherfoord, John; Ruwiedel, Christoph; Ruzicka, Pavel; Ryabov, Yury; Ryadovikov, Vasily; Ryan, Patrick; Rybar, Martin; Rybkin, Grigori; Ryder, Nick; Rzaeva, Sevda; Saavedra, Aldo; Sadeh, Iftach; Sadrozinski, Hartmut; Sadykov, Renat; Safai Tehrani, Francesco; Sakamoto, Hiroshi; Salamanna, Giuseppe; Salamon, Andrea; Saleem, Muhammad; Salihagic, Denis; Salnikov, Andrei; Salt, José; Salvachua Ferrando, Belén; Salvatore, Daniela; Salvatore, Pasquale Fabrizio; Salvucci, Antonio; Salzburger, Andreas; Sampsonidis, Dimitrios; Samset, Björn Hallvard; Sanchez, Arturo; Sanchez Martinez, Victoria; Sandaker, Heidi; Sander, Heinz Georg; Sanders, Michiel; Sandhoff, Marisa; Sandoval, Tanya; Sandoval, Carlos; Sandstroem, Rikard; Sandvoss, Stephan; Sankey, Dave; Sansoni, Andrea; Santamarina Rios, Cibran; Santoni, Claudio; Santonico, Rinaldo; Santos, Helena; Sapronov, Andrey; Saraiva, João; Sarangi, Tapas; Sarkisyan-Grinbaum, Edward; Sarri, Francesca; Sartisohn, Georg; Sasaki, Osamu; Sasao, Noboru; Satsounkevitch, Igor; Sauvage, Gilles; Sauvan, Emmanuel; Sauvan, Jean-Baptiste; Savard, Pierre; Savinov, Vladimir; Savu, Dan Octavian; Sawyer, Lee; Saxon, David; Says, Louis-Pierre; Sbarra, Carla; Sbrizzi, Antonio; Scallon, Olivia; Scannicchio, Diana; Scarcella, Mark; Schaarschmidt, Jana; Schacht, Peter; Schäfer, Uli; Schaepe, Steffen; Schaetzel, Sebastian; Schaffer, Arthur; Schaile, Dorothee; Schamberger, R~Dean; Schamov, Andrey; Scharf, Veit; Schegelsky, Valery; Scheirich, Daniel; Schernau, Michael; Scherzer, Max; Schiavi, Carlo; Schieck, Jochen; Schioppa, Marco; Schlenker, Stefan; Schlereth, James; Schmidt, Evelyn; Schmieden, Kristof; Schmitt, Christian; Schmitt, Sebastian; Schmitz, Martin; Schöning, André; Schott, Matthias; Schouten, Doug; Schovancova, Jaroslava; Schram, Malachi; Schroeder, Christian; Schroer, Nicolai; Schuler, Georges; Schultens, Martin Johannes; Schultes, Joachim; Schultz-Coulon, Hans-Christian; Schulz, Holger; Schumacher, Jan; Schumacher, Markus; Schumm, Bruce; Schune, Philippe; Schwanenberger, Christian; Schwartzman, Ariel; Schwemling, Philippe; Schwienhorst, Reinhard; Schwierz, Rainer; Schwindling, Jerome; Schwindt, Thomas; Schwoerer, Maud; Scott, Bill; Searcy, Jacob; Sedov, George; Sedykh, Evgeny; Segura, Ester; Seidel, Sally; Seiden, Abraham; Seifert, Frank; Seixas, José; Sekhniaidze, Givi; Selbach, Karoline Elfriede; Seliverstov, Dmitry; Sellden, Bjoern; Sellers, Graham; Seman, Michal; Semprini-Cesari, Nicola; Serfon, Cedric; Serin, Laurent; Serkin, Leonid; Seuster, Rolf; Severini, Horst; Sevior, Martin; Sfyrla, Anna; Shabalina, Elizaveta; Shamim, Mansoora; Shan, Lianyou; Shank, James; Shao, Qi Tao; Shapiro, Marjorie; Shatalov, Pavel; Shaver, Leif; Shaw, Kate; Sherman, Daniel; Sherwood, Peter; Shibata, Akira; Shichi, Hideharu; Shimizu, Shima; Shimojima, Makoto; Shin, Taeksu; Shiyakova, Maria; Shmeleva, Alevtina; Shochet, Mel; Short, Daniel; Shrestha, Suyog; Shulga, Evgeny; Shupe, Michael; Sicho, Petr; Sidoti, Antonio; Siegert, Frank; Sijacki, Djordje; Silbert, Ohad; Silva, José; Silver, Yiftah; Silverstein, Daniel; Silverstein, Samuel; Simak, Vladislav; Simard, Olivier; Simic, Ljiljana; Simion, Stefan; Simmons, Brinick; Simonyan, Margar; Sinervo, Pekka; Sinev, Nikolai; Sipica, Valentin; Siragusa, Giovanni; Sircar, Anirvan; Sisakyan, Alexei; Sivoklokov, Serguei; Sjölin, Jörgen; Sjursen, Therese; Skinnari, Louise Anastasia; Skottowe, Hugh Philip; Skovpen, Kirill; Skubic, Patrick; Skvorodnev, Nikolai; Slater, Mark; Slavicek, Tomas; Sliwa, Krzysztof; Sloper, John erik; Smakhtin, Vladimir; Smart, Ben; Smirnov, Sergei; Smirnov, Yury; Smirnova, Lidia; Smirnova, Oxana; Smith, Ben Campbell; Smith, Douglas; Smith, Kenway; Smizanska, Maria; Smolek, Karel; Snesarev, Andrei; Snow, Steve; Snow, Joel; Snuverink, Jochem; Snyder, Scott; Soares, Mara; Sobie, Randall; Sodomka, Jaromir; Soffer, Abner; Solans, Carlos; Solar, Michael; Solc, Jaroslav; Soldatov, Evgeny; Soldevila, Urmila; Solfaroli Camillocci, Elena; Solodkov, Alexander; Solovyanov, Oleg; Soni, Nitesh; Sopko, Vit; Sopko, Bruno; Sosebee, Mark; Soualah, Rachik; Soukharev, Andrey; Spagnolo, Stefania; Spanò, Francesco; Spighi, Roberto; Spigo, Giancarlo; Spila, Federico; Spiwoks, Ralf; Spousta, Martin; Spreitzer, Teresa; Spurlock, Barry; St Denis, Richard Dante; Stahlman, Jonathan; Stamen, Rainer; Stanecka, Ewa; Stanek, Robert; Stanescu, Cristian; Stapnes, Steinar; Starchenko, Evgeny; Stark, Jan; Staroba, Pavel; Starovoitov, Pavel; Staude, Arnold; Stavina, Pavel; Steele, Genevieve; Steinbach, Peter; Steinberg, Peter; Stekl, Ivan; Stelzer, Bernd; Stelzer, Harald Joerg; Stelzer-Chilton, Oliver; Stenzel, Hasko; Stern, Sebastian; Stevenson, Kyle; Stewart, Graeme; Stillings, Jan Andre; Stockton, Mark; Stoerig, Kathrin; Stoicea, Gabriel; Stonjek, Stefan; Strachota, Pavel; Stradling, Alden; Straessner, Arno; Strandberg, Jonas; Strandberg, Sara; Strandlie, Are; Strang, Michael; Strauss, Emanuel; Strauss, Michael; Strizenec, Pavol; Ströhmer, Raimund; Strom, David; Strong, John; Stroynowski, Ryszard; Strube, Jan; Stugu, Bjarne; Stumer, Iuliu; Stupak, John; Sturm, Philipp; Styles, Nicholas Adam; Soh, Dart-yin; Su, Dong; Subramania, Halasya Siva; Succurro, Antonella; Sugaya, Yorihito; Sugimoto, Takuya; Suhr, Chad; Suita, Koichi; Suk, Michal; Sulin, Vladimir; Sultansoy, Saleh; Sumida, Toshi; Sun, Xiaohu; Sundermann, Jan Erik; Suruliz, Kerim; Sushkov, Serge; Susinno, Giancarlo; Sutton, Mark; Suzuki, Yu; Suzuki, Yuta; Svatos, Michal; Sviridov, Yuri; Swedish, Stephen; Sykora, Ivan; Sykora, Tomas; Szeless, Balazs; Sánchez, Javier; Ta, Duc; Tackmann, Kerstin; Taffard, Anyes; Tafirout, Reda; Taiblum, Nimrod; Takahashi, Yuta; Takai, Helio; Takashima, Ryuichi; Takeda, Hiroshi; Takeshita, Tohru; Takubo, Yosuke; Talby, Mossadek; Talyshev, Alexey; Tamsett, Matthew; Tanaka, Junichi; Tanaka, Reisaburo; Tanaka, Satoshi; Tanaka, Shuji; Tanaka, Yoshito; Tanasijczuk, Andres Jorge; Tani, Kazutoshi; Tannoury, Nancy; Tappern, Geoffrey; Tapprogge, Stefan; Tardif, Dominique; Tarem, Shlomit; Tarrade, Fabien; Tartarelli, Giuseppe Francesco; Tas, Petr; Tasevsky, Marek; Tassi, Enrico; Tatarkhanov, Mous; Tayalati, Yahya; Taylor, Christopher; Taylor, Frank; Taylor, Geoffrey; Taylor, Wendy; Teinturier, Marthe; Teixeira Dias Castanheira, Matilde; Teixeira-Dias, Pedro; Temming, Kim Katrin; Ten Kate, Herman; Teng, Ping-Kun; Terada, Susumu; Terashi, Koji; Terron, Juan; Testa, Marianna; Teuscher, Richard; Thadome, Jocelyn; Therhaag, Jan; Theveneaux-Pelzer, Timothée; Thioye, Moustapha; Thoma, Sascha; Thomas, Juergen; Thompson, Emily; Thompson, Paul; Thompson, Peter; Thompson, Stan; Thomsen, Lotte Ansgaard; Thomson, Evelyn; Thomson, Mark; Thun, Rudolf; Tian, Feng; Tibbetts, Mark James; Tic, Tomáš; Tikhomirov, Vladimir; Tikhonov, Yury; Timoshenko, Sergey; Tipton, Paul; Tique Aires Viegas, Florbela De Jes; Tisserant, Sylvain; Toczek, Barbara; Todorov, Theodore; Todorova-Nova, Sharka; Toggerson, Brokk; Tojo, Junji; Tokár, Stanislav; Tokunaga, Kaoru; Tokushuku, Katsuo; Tollefson, Kirsten; Tomoto, Makoto; Tompkins, Lauren; Toms, Konstantin; Tong, Guoliang; Tonoyan, Arshak; Topfel, Cyril; Topilin, Nikolai; Torchiani, Ingo; Torrence, Eric; Torres, Heberth; Torró Pastor, Emma; Toth, Jozsef; Touchard, Francois; Tovey, Daniel; Trefzger, Thomas; Tremblet, Louis; Tricoli, Alesandro; Trigger, Isabel Marian; Trincaz-Duvoid, Sophie; Trinh, Thi Nguyet; Tripiana, Martin; Trischuk, William; Trivedi, Arjun; Trocmé, Benjamin; Troncon, Clara; Trottier-McDonald, Michel; Trzebinski, Maciej; Trzupek, Adam; Tsarouchas, Charilaos; Tseng, Jeffrey; Tsiakiris, Menelaos; Tsiareshka, Pavel; Tsionou, Dimitra; Tsipolitis, Georgios; Tsiskaridze, Vakhtang; Tskhadadze, Edisher; Tsukerman, Ilya; Tsulaia, Vakhtang; Tsung, Jieh-Wen; Tsuno, Soshi; Tsybychev, Dmitri; Tua, Alan; Tudorache, Alexandra; Tudorache, Valentina; Tuggle, Joseph; Turala, Michal; Turecek, Daniel; Turk Cakir, Ilkay; Turlay, Emmanuel; Turra, Ruggero; Tuts, Michael; Tykhonov, Andrii; Tylmad, Maja; Tyndel, Mike; Tzanakos, George; Uchida, Kirika; Ueda, Ikuo; Ueno, Ryuichi; Ugland, Maren; Uhlenbrock, Mathias; Uhrmacher, Michael; Ukegawa, Fumihiko; Unal, Guillaume; Underwood, David; Undrus, Alexander; Unel, Gokhan; Unno, Yoshinobu; Urbaniec, Dustin; Usai, Giulio; Uslenghi, Massimiliano; Vacavant, Laurent; Vacek, Vaclav; Vachon, Brigitte; Vahsen, Sven; Valenta, Jan; Valente, Paolo; Valentinetti, Sara; Valkar, Stefan; Valladolid Gallego, Eva; Vallecorsa, Sofia; Valls Ferrer, Juan Antonio; van der Graaf, Harry; van der Kraaij, Erik; Van Der Leeuw, Robin; van der Poel, Egge; van der Ster, Daniel; van Eldik, Niels; van Gemmeren, Peter; van Kesteren, Zdenko; van Vulpen, Ivo; Vanadia, Marco; Vandelli, Wainer; Vandoni, Giovanna; Vaniachine, Alexandre; Vankov, Peter; Vannucci, Francois; Varela Rodriguez, Fernando; Vari, Riccardo; Varnes, Erich; Varouchas, Dimitris; Vartapetian, Armen; Varvell, Kevin; Vassilakopoulos, Vassilios; Vazeille, Francois; Vazquez Schroeder, Tamara; Vegni, Guido; Veillet, Jean-Jacques; Vellidis, Constantine; Veloso, Filipe; Veness, Raymond; Veneziano, Stefano; Ventura, Andrea; Ventura, Daniel; Venturi, Manuela; Venturi, Nicola; Vercesi, Valerio; Verducci, Monica; Verkerke, Wouter; Vermeulen, Jos; Vest, Anja; Vetterli, Michel; Vichou, Irene; Vickey, Trevor; Vickey Boeriu, Oana Elena; Viehhauser, Georg; Viel, Simon; Villa, Mauro; Villaplana Perez, Miguel; Vilucchi, Elisabetta; Vincter, Manuella; Vinek, Elisabeth; Vinogradov, Vladimir; Virchaux, Marc; Virzi, Joseph; Vitells, Ofer; Viti, Michele; Vivarelli, Iacopo; 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Weidberg, Anthony; Weigell, Philipp; Weingarten, Jens; Weiser, Christian; Wellenstein, Hermann; Wells, Phillippa; Wenaus, Torre; Wendland, Dennis; Wendler, Shanti; Weng, Zhili; Wengler, Thorsten; Wenig, Siegfried; Wermes, Norbert; Werner, Matthias; Werner, Per; Werth, Michael; Wessels, Martin; Weydert, Carole; Whalen, Kathleen; Wheeler-Ellis, Sarah Jane; Whitaker, Scott; White, Andrew; White, Martin; Whitehead, Samuel Robert; Whiteson, Daniel; Whittington, Denver; Wicek, Francois; Wicke, Daniel; Wickens, Fred; Wiedenmann, Werner; Wielers, Monika; Wienemann, Peter; Wiglesworth, Craig; Wiik-Fuchs, Liv Antje Mari; Wijeratne, Peter Alexander; Wildauer, Andreas; Wildt, Martin Andre; Wilhelm, Ivan; Wilkens, Henric George; Will, Jonas Zacharias; Williams, Eric; Williams, Hugh; Willis, William; Willocq, Stephane; Wilson, John; Wilson, Michael Galante; Wilson, Alan; Wingerter-Seez, Isabelle; Winkelmann, Stefan; Winklmeier, Frank; Wittgen, Matthias; Wolter, Marcin Wladyslaw; Wolters, Helmut; Wong, Wei-Cheng; Wooden, Gemma; Wosiek, Barbara; Wotschack, Jorg; Woudstra, Martin; Wozniak, Krzysztof; Wraight, Kenneth; Wright, Catherine; Wright, Michael; Wrona, Bozydar; Wu, Sau Lan; Wu, Xin; Wu, Yusheng; Wulf, Evan; Wunstorf, Renate; Wynne, Benjamin; Xella, Stefania; Xiao, Meng; Xie, Song; Xie, Yigang; Xu, Chao; Xu, Da; Xu, Guofa; Yabsley, Bruce; Yacoob, Sahal; Yamada, Miho; Yamaguchi, Hiroshi; Yamamoto, Akira; Yamamoto, Kyoko; Yamamoto, Shimpei; Yamamura, Taiki; Yamanaka, Takashi; Yamaoka, Jared; Yamazaki, Takayuki; Yamazaki, Yuji; Yan, Zhen; Yang, Haijun; Yang, Un-Ki; Yang, Yi; Yang, Yi; Yang, Zhaoyu; Yanush, Serguei; Yao, Yushu; Yasu, Yoshiji; Ybeles Smit, Gabriel Valentijn; Ye, Jingbo; Ye, Shuwei; Yilmaz, Metin; Yoosoofmiya, Reza; Yorita, Kohei; Yoshida, Riktura; Young, Charles; Youssef, Saul; Yu, Dantong; Yu, Jaehoon; Yu, Jie; Yuan, Li; Yurkewicz, Adam; Zabinski, Bartlomiej; Zaets, Vassilli; Zaidan, Remi; Zaitsev, Alexander; Zajacova, Zuzana; Zanello, Lucia; Zaytsev, Alexander; Zeitnitz, Christian; Zeller, Michael; Zeman, Martin; Zemla, Andrzej; Zendler, Carolin; Zenin, Oleg; Ženiš, Tibor; Zinonos, Zinonas; Zenz, Seth; Zerwas, Dirk; Zevi della Porta, Giovanni; Zhan, Zhichao; Zhang, Dongliang; Zhang, Huaqiao; Zhang, Jinlong; Zhang, Xueyao; Zhang, Zhiqing; Zhao, Long; Zhao, Tianchi; Zhao, Zhengguo; Zhemchugov, Alexey; Zheng, Shuchen; Zhong, Jiahang; Zhou, Bing; Zhou, Ning; Zhou, Yue; Zhu, Cheng Guang; Zhu, Hongbo; Zhu, Junjie; Zhu, Yingchun; Zhuang, Xuai; Zhuravlov, Vadym; Zieminska, Daria; Zimmermann, Robert; Zimmermann, Simone; Zimmermann, Stephanie; Ziolkowski, Michael; Zitoun, Robert; Živković, Lidija; Zmouchko, Viatcheslav; Zobernig, Georg; Zoccoli, Antonio; Zolnierowski, Yves; Zsenei, Andras; zur Nedden, Martin; Zutshi, Vishnu; Zwalinski, Lukasz
2012-01-01
A QCD analysis is reported of ATLAS data on inclusive W and Z boson production in pp collisions at the LHC, jointly with ep deep inelastic scattering data from HERA. The ATLAS data exhibit sensitivity to the light quark sea composition and magnitude at Bjorken x ~ 0.01. Specifically, the data support the hypothesis of a symmetric composition of the light quark sea at low x. The ratio of the strange-to-down sea quark distributions is determined to be 1.00(+0.25-0.28) at absolute four-momentum transfer squared Q^2 = 1.9 GeV^2 and x = 0.023.
Koponen, Jonna; Davies, Christine T H; Donald, Gordon; Dowdall, Rachel; de Oliveira, Pedro Goncalves; Lepage, G Peter; Teubner, Thomas
2014-01-01
We describe a new technique (published in Phys. Rev. D89 114501) to determine the contribution to the anomalous magnetic moment of the muon coming from the hadronic vacuum polarisation using lattice QCD. Our method uses Pad\\'e approximants to reconstruct the Adler function from its derivatives at $q^2=0$. These are obtained simply and accurately from time-moments of the vector current-current correlator at zero spatial momentum. We test the method using strange quark correlators calculated on MILC Collaboration's $n_f = 2+1+1$ HISQ ensembles at multiple values of the lattice spacing, multiple volumes and multiple light sea quark masses (including physical pion mass configurations). We find the (connected) contribution to the anomalous moment from the strange quark vacuum polarisation to be $a^s_\\mu=53.41(59)\\times 10^{-10}$, and the contribution from charm quarks to be $a^c_\\mu=14.42(39)\\times 10^{-10}$ - 1% accuracy is achieved for the strange quark contribution. The extension of our method to the light quar...
Dai, Z G; Wang, J S; Wang, L J; Yu, Y W
2015-01-01
Strange quark stars (SQSs), consisting of quark matter with comparable numbers of deconfined up, down and strange quarks, have so far remained a hypothetical class of compact objects. Observationally, it is difficult to distinguish between SQSs and neutron stars (NSs), because both classes of stars have similar structural and cooling features for stellar masses above one solar mass. Here we show that the most luminous supernova discovered recently, ASASSN-15lh, could have been powered by a newborn strongly-magnetized pulsar rotating with a nearly Keplerian period. A quick rotational-energy loss as a result of gravitational-radiation-driven r-mode instability in a hot young rapidly rotating NS, together with the fact that this instability is highly suppressed due to large bulk viscosity in an SQS, leads to the conclusion that such an ultra-energetic supernova may provide a "smoking gun" signature for the birth of an SQS.
Search for exotic penta quark baryons with hidden strangeness in the experiment on the SPHINX setup
International Nuclear Information System (INIS)
The results of studying the diffractive production reactions on the IHEP proton beam with Ep = 70 GeV on the SPHINX setup are discussed. The searches for exotic penta-quark baryons with hidden strangeness are performed in these processes. The main results were obtained for the reaction p + N → [Σ0K+] + N, where in the invariant mass spectrum M(Σ0K+) the peak with parameters M = 1989 ± 6 MeV and Γ = 91 ± 20 MeV is dominated. The anomalous properties of this state make it a serious candidate for exotic baryon. The additional data which are supported the real existence of this baryon are also presented
Energy Technology Data Exchange (ETDEWEB)
Bietenholz, W. [Univ. Autonoma de Mexico, Mexico City (Mexico). Inst. de Ciencias Nucleares; Bornyakov, V. [Inst. for High Energy Physics, Protovino (Russian Federation); Inst. for Theoretical and Experimental Physics, Moscow (Russian Federation); Goeckeler, M. [Regensburg Univ. (DE). Inst. fuer Theoretische Physik] (and others)
2011-02-15
QCD lattice simulations with 2+1 flavours typically start at rather large up-down and strange quark masses and extrapolate first the strange quark mass to its physical value and then the up-down quark mass. An alternative method of tuning the quark masses is discussed here in which the singlet quark mass is kept fixed, which ensures that the kaon always has mass less than the physical kaon mass. Using group theory the possible quark mass polynomials for a Taylor expansion about the flavour symmetric line are found, first for the general 1+1+1 flavour case and then for the 2+1 flavour case (when two quark flavours are mass degenerate). These enable highly constrained fits to be used in the extrapolation of hadrons to the physical pion mass. Numerical results for the 2+1 flavour case confirm the usefulness of this expansion and an extrapolation to the physical pion mass gives hadron mass values to within a few percent of their experimental values. Singlet quantities remain constant which allows the lattice spacing to be determined from hadron masses (without necessarily being at the physical point). Furthermore an extension of this programme to include partially quenched results is also given. (orig.)
Fast spinning strange stars: possible ways to constrain interacting quark matter parameters
Bhattacharyya, Sudip; Bombaci, Ignazio; Logoteta, Domenico; Thampan, Arun V.
2016-04-01
For a set of equation of state (EoS) models involving interacting strange quark matter, characterized by an effective bag constant (Beff) and a perturbative quantum chromodynamics corrections term (a4), we construct fully general relativistic equilibrium sequences of rapidly spinning strange stars for the first time. Computation of such sequences is important to study millisecond pulsars and other fast spinning compact stars. Our EoS models can support a gravitational mass (MG) and a spin frequency (ν) at least up to ≈3.0 M⊙ and ≈1250 Hz, respectively, and hence are fully consistent with measured MG and ν values. This paper reports the effects of Beff and a4 on measurable compact star properties, which could be useful to find possible ways to constrain these fundamental quark matter parameters, within the ambit of our EoS models. We confirm that a lower Beff allows a higher mass. Besides, for known MG and ν, measurable parameters, such as stellar radius, radius-to-mass ratio and moment of inertia, increase with the decrease of Beff. Our calculations also show that a4 significantly affects the stellar rest mass and the total stellar binding energy. As a result, a4 can have signatures in evolutions of both accreting and non-accreting compact stars, and the observed distribution of stellar mass and spin and other source parameters. Finally, we compute the parameter values of two important pulsars, PSR J1614-2230 and PSR J1748-2446ad, which may have implications to probe their evolutionary histories, and for constraining EoS models.
Stolarski, M
2012-01-01
In this paper the author discusses the article by the HERMES Collaboration, Phys. Lett. B 666, 446 [arXiv:0803.2993], where several important results concerning strange quark properties in the nucleon were presented. The strange sea distribution was found to be very different from the non-strange in the Bjorken x scaling variable. In addition, the magnitude of these two distributions at low x is similar, contrary to most of the available Parton Distribution Function sets. The strange quark helicity distribution was also extracted combining inclusive and semi-inclusive kaon asymmetries. The result of the first moment of the strange quarks helicity distribution in the measured range is slightly positive, while a rather significant negative value is expected from the world polarised inclusive Deep Inelastic Scattering measurements. The author shows that a certain combination of fragmentation functions extracted from the preliminary HERMES kaon multiplicities presents a very strong Q2 dependence. Such a strong de...
Asatrian, H M
2014-01-01
We calculate the O(alpha_s) corrections to the double differential decay width dGamma_{77}/(ds_1 ds_2) for the process B -> X_s gamma gamma originating from diagrams involving the electromagnetic dipole operator O_7. The kinematical variables s_1 and s_2 are defined as s_i=(p_b - q_i)^2/m_b^2, where p_b, q_1, q_2 are the momenta of b-quark and two photons. We introduce a nonzero mass m_s for the strange quark to regulate configurations where the gluon or one of the photons become collinear with the strange quark and retain terms which are logarithmic in m_s, while discarding terms which go to zero in the limit m_s -> 0. When combining virtual- and bremsstrahlung corrections, the infrared and collinear singularities induced by soft and/or collinear gluons drop out. By our cuts the photons do not become soft, but one of them can become collinear with the strange quark. This implies that in the final result a single logarithms of m_s survives. In principle the configurations with collinear photon emission could ...
Are there non-strange low-lying penta-quarks and can we understand their width
Gothe, R W
2003-01-01
We argue that the lightest isospin 1/2 partners of the Z^+(1530) s(bar)uudd penta-quark predicted by Diakonov, Petrov and Polyakov are not the N(1710) mixed anti-decuplet states, but the pure non-strange u(bar)(ud)(ud) and d(bar)(ud)(ud) penta-quark states which may lie as low as 1200 MeV. The expected low width of a few MeV of such a putative state may explain why it was missed in phase shift analyzes of pion-nucleon scattering.
International Nuclear Information System (INIS)
In the framework of the Quantum Chromodynamics (QCD), the nucleon is described as being composed of three valence quarks surrounded by a sea of virtual quark-antiquark pairs and gluons. If the role of this virtual sea in the nucleon properties is inferred to be important, this contribution is still poorly understood. In this context, we study the role of the strange quarks in the nucleon since this is the lightest quark flavor of the sea with no valence contribution. We are determining its contribution to the charge and magnetization distributions in the nucleon via parity violation experiments. The measurement is performed by elastically scattering polarized electrons from nucleon target. A world wide program in which the G0 experiment takes place has been performing for a decade. The G0 experiment and the analysis of the results from its forward angles phase are the topics of this thesis. This document presents the physics case of the strangeness content of the nucleon (mass, spin, impulsion). It describes also the formalism related to the electroweak probe and the form factors, and then the principle of parity violating asymmetry measurement. The G0 experimental setup, which was built and installed in the Hall C of the Jefferson Laboratory (Usa), is detailed. This set-up was designed for the measurement of asymmetries of the order of 10-6 with an overall relative uncertainty better than 10 %, over a momentum transfer range 0.1-1 (GeV/c)2. The various steps of the data analysis are exposed. They have allowed us to start from measured counting rates to reach parity violating physics asymmetries. This required a careful treatment of the various sources of systematical errors which is discussed extensively. Finally the results from the G0 forward angle measurement, its comparison with others experiments and with theoretical models, are presented. They support a non null strange quark contribution. (author)
New upper limit on strange quark matter abundance in cosmic rays with the PAMELA space experiment.
Adriani, O; Barbarino, G C; Bazilevskaya, G A; Bellotti, R; Boezio, M; Bogomolov, E A; Bongi, M; Bonvicini, V; Bottai, S; Bruno, A; Cafagna, F; Campana, D; Carlson, P; Casolino, M; Castellini, G; De Donato, C; De Santis, C; De Simone, N; Di Felice, V; Formato, V; Galper, A M; Karelin, A V; Koldashov, S V; Koldobskiy, S; Krutkov, S Y; Kvashnin, A N; Leonov, A; Malakhov, V; Marcelli, L; Martucci, M; Mayorov, A G; Menn, W; Mergè, M; Mikhailov, V V; Mocchiutti, E; Monaco, A; Mori, N; Munini, R; Osteria, G; Palma, F; Panico, B; Papini, P; Pearce, M; Picozza, P; Ricci, M; Ricciarini, S B; Sarkar, R; Scotti, V; Simon, M; Sparvoli, R; Spillantini, P; Stozhkov, Y I; Vacchi, A; Vannuccini, E; Vasilyev, G; Voronov, S A; Yurkin, Y T; Zampa, G; Zampa, N
2015-09-11
In this work we present results of a direct search for strange quark matter (SQM) in cosmic rays with the PAMELA space spectrometer. If this state of matter exists it may be present in cosmic rays as particles, called strangelets, having a high density and an anomalously high mass-to-charge (A/Z) ratio. A direct search in space is complementary to those from ground-based spectrometers. Furthermore, it has the advantage of being potentially capable of directly identifying these particles, without any assumption on their interaction model with Earth's atmosphere and the long-term stability in terrestrial and lunar rocks. In the rigidity range from 1.0 to ∼1.0×10^{3} GV, no such particles were found in the data collected by PAMELA between 2006 and 2009. An upper limit on the strangelet flux in cosmic rays was therefore set for particles with charge 1≤Z≤8 and mass 4≤A≤1.2×10^{5}. This limit as a function of mass and as a function of magnetic rigidity allows us to constrain models of SQM production and propagation in the Galaxy. PMID:26406816
International Nuclear Information System (INIS)
Phase transition of the color superconducting state to the quark plasma (QGP) at finite temperature is studied using the Schwinger-Dyson (SD) method in the improved ladder approximation. We compare the Cornwall-Jackiw-Tomboulis effective potential at finite temperature for two types of the color superconductor, namely the Color-Flavor locking (CFL) state and the 2flavor superconducting (2SC) state. Despite the fact that the energy density of the CFL phase is almost twice as that of the 2SC phase for all temperature, the critical temperatures of the two phases to QGP coincide: This fact implies that the CFL phase is more fragile than the 2SC state against thermal fluctuations. Effect of the strange quark mass ms on the quark-pairing is also examined. In particular, using a simple kinematical criterion, we extract ms-dependence of the ''unlocking line'' on which the CFL phase turns into the 2SC phase. (author)
PREFACE: 14th International Conference on Strangeness in Quark Matter (SQM2013)
2014-05-01
The 2013 Strangeness in Quark Matter conference took place at the University of Birmingham in July 2013, in a period of remarkably good weather that gave a very welcome boost to the event. 158 physicists from 25 countries gathered for a week of discussions on the production of strangeness and heavy flavour in heavy ion collisions. The dates for the meeting had been set two years earlier in Cracow, so as to allow it to offer the first major examination of proton-lead collisions from the Large Hadron Collider. It had originally been thought that these collisions would be recorded by the end of 2012, but in the event it turned out that the running period was postponed until January and February of 2013, giving the LHC collaborations - all four major collaborations since LHCb also took part in pPb data taking - very little time to prepare their results. Nevertheless, new results were provided, and their presentation and interpretation formed one of the highlights of the conference. In addition, there was a more detailed assessment of the RHIC beam energy scan, many new heavy flavour results from the RHIC and LHC heavy ion runs and detailed discussions of the future FAIR and NICA programmes. The conference also hosted a good cross-section of current topics in theoretical talks. In the last few years there has been much interest in thermalization and in the use of hydrodynamics to describe the fluctuations visible in higher-order flow coefficients. Discussions of both of these features were well represented, indicating the maturing of this field. We gratefully acknowledge support from The University of Birmingham, CERN, The Extreme Matter Institute (EMMI), the Institute for Particle Physics Phenomenology (IPPP), Institute of Physics Publishing and from the UK Science and Technology Facilities Council (STFC). This assistance allowed us to support over twenty young physicists, and allowed us to ensure that we had the breadth of programme needed for a successful conference
Ćaǧlar, Halife; Aygün, Sezgin
2016-03-01
In this study, we have investigated bulk viscous with strange quark matter attached to the string cloud for higher dimensional Friedman-Robertson-Walker (FRW) universe in Lyra geometry. By using varying deceleration parameter and conservation equations we have solved Einstein Field Equations (EFE's) and obtained generalized exact solutions for our model. Also we have found that string is not survived for bulk viscous with strange quark matter attached to the string cloud in framework higher dimensional FRW universe in Lyra geometry. This result agrees with Kiran and Reddy, Krori et al, Sahoo and Mishra and Mohanty et al. in four and five dimensions.
PREFACE: 15th International Conference on Strangeness in Quark Matter (SQM2015)
Alvarez-Castillo, D.; Blaschke, D.; Kekelidze, V.; Matveev, V.; Sorin, A.
2016-01-01
The 15th International Conference Strangeness in Quark Matter (SQM) took place at the Veksler and Baldin Laboratory of High Energy Physics (VBLHEP) of the Joint Institute for Nuclear Research (JINR) in Dubna in the period July 6 -11, with a record participation of 244 people from 31 countries! The previous meeting of the series in Birmingham 2013 had collected 158 physicists from 25 countries [J. Phys. Conf. Ser. 509, 011001 (2014)]. At SQM-2015, there was also a record participation of young scientist; every 4th conference attendee did not yet hold a PhD degree! There was a special program of 4 general lectures, a devoted session of parallel talks for Young Talents and the Helmholtz International Summer School (HISS) with 16 lecturers on the topics regarding Dense Matter (29.06.-11.07.) as a satellite event at the Bogoliubov Laboratory of Theoretical Physics (BLTP) and at VBLHEP. Another satellite event was the Round TableWorkshop on Physics at NICA, jointly organized by JINR and the Republic of South Africa on July 5, 2015. The selection of Dubna as the place for SQM-2015 conference by the International Advisory Committee (IAC) demonstrates the broad interest of the community in the progress of the Russian Megascience Project on the Nuclotron-based Ion Collider Facility (NICA) hosted at JINR Dubna. In a few years from now the experiments planned at NICA will produce data that provide new information of unprecedented accuracy which will help to answer some of the key questions which are topical at this conference. The SQM-2015 conference had an ambitious scientific program with 38 plenary talks, 97 parallel talks in 7 topical directions and 39 posters reporting the state of the research and the future directions in the fields of strangeness, heavy avors and bulk physics, suggested by the IAC to be the subtitle of the conference from 2016 onwards. Most of the contributions are represented in these Proceedings which we recommend to the community! We gratefully
PREFACE: SQM2004 The 8th International Conference on Strangeness in Quark Matter
Cleymans, Jean; Steinberg, Peter; Vilakazi, Zeblon
2005-06-01
The 8th International Conference on Strangeness in Quark Matter (SQM2004) was held at at the Breakwater Lodge, which is part of the Graduate School of Business of the University of Cape Town. The architecture of the Breakwater Lodge is a stark reminder of the fact that its original purpose was to serve as a municipal jail. It appears that the spectacular background of Table Mountain and the V&A Waterfront and an excellent set of speakers were sufficient to keep the lecture rooms full to capacity, despite the numerous temptations of Cape Town. This is the first time a major heavy ion conference has been held in South Africa, and the timing is fortuitous, with a long-delayed MoU between South Africa and CERN at last being signed and finalized. At last, funding is being made available for South African scientists to play a meaningful role and make contributions to the international effort in heavy ion physics. Despite the substantial distance from the major cities in the northern hemisphere, the conference was very well attended and the number of participants was about 50% larger than originally anticipated. Participants came from China, India, Japan, the United States, Brazil and many European countries. We would like to thank all of the SQM2004 participants for their efforts and, in particlular, all of the plenary and parallel speakers for their hard work in making this conference such a success. Of course, even more thanks go to all the chairpersons of the various sessions who struggled to keep the conference program on the (admittedly tight) schedule. For future conferences, we recommend keeping a bell handy! Photograph Participants gather on the UCT campus with Table Mountain in the backgound. We would like to thank Professor Tony Fairall for a most entertaining after-dinner talk about all that is unusual and fascinating about the southern hemisphere. It could not be emphasized enough that the daily working of the meeting would have ground to a halt without the
Superbursts from Strange Stars
Page, D; Page, Dany; Cumming, Andrew
2005-01-01
Recent models of carbon ignition on accreting neutron stars predict superburst ignition depths that are an order of magnitude larger than observed. We explore a possible solution to this problem, that the compact stars in low mass X-ray binaries that have shown superbursts are in fact strange stars with a crust of normal matter. We calculate the properties of superbursts on strange stars, and the resulting constraints on the properties of strange quark matter. We show that the observed ignition conditions exclude fast neutrino emission in the quark core, for example by the direct Urca process, which implies that strange quark matter at stellar densities should be in a color superconducting state. For slow neutrino emission in the quark matter core, we find that reproducing superburst properties requires a definite relation between three poorly constrained properties of strange quark matter: its thermal conductivity, its slow neutrino emissivity and the energy released by converting a nucleon into strange quar...
From strangelets to strange stars: A unified description
Xia, Cheng-Jun; Zhao, En-Guang; Zhou, Shan-Gui
2015-01-01
The conventionally separated treatments for strangelets and strange stars are now unified with a more comprehensive theoretical description for objects ranging from strangelets to strange stars. After constraining the model parameter according to the Witten-Bodmer hypothesis and observational mass-radius probability distribution of pulsars, we investigate the properties of this kind of objects. It is found that the energy per baryon decreases monotonously for increasing baryon number and reaches its minimum at the maximum baryon number, corresponding to the most massive strange star. Due to the quark depletion, an electric potential well for negatively charged particles is formed on the surface of the quark part, which may provide some unique observables. For a rotational bare strange star, a magnetic field with the typical strength of pulsars is generated.
Institute of Scientific and Technical Information of China (English)
PENG Jin-Song; ZHOU Li-Juan; MENG Cheng-Ju; PAN Ji-Huan; MA Wei-Xing; YUAN Tong-Quan
2013-01-01
Based on the fully dressed quark propagator and chiral perturbation theory,we study the ratio of the strange quark mass ms to up or down quark mass mu,d.The ratio is related to the determination of quark masses which are fundamental input parameters of QCD Lagrangian in the Standard Model of particle physics and can not be directly measured since the quark is confined within a hadron.An accurate determination of these QCD free parameters is extremely important for both phenomenological and theoretical applications.We begin with a brief introduction to the non-perturbation QCD theory,and then study the mass ratio in the framework of the chiral perturbation theory (xPT) with a parameterized fully dressed quark propagator which describes confining fully dressed quark propagation and is analytic everywhere in the finite complex p2-plane and has no Lehmann representation so there are no quark production thresholds in any theoretical calculations of observable data.Our prediction for the ratio ms/mu,d is consistent with other model predictions such as Lattice QCD,instanton model,QCD sum rules and the empirical values used widely in the literature.As a by-product of this study,our theoretical results,together with other predictions of physical quantities that used this quark propagator in our previous publications,clearly show that the parameterized form of the fully dressed quark propagator is an applicable and reliable approximation to the solution of the Dyson-Schwinger Equation of quark propagator in the QCD.
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.
International Nuclear Information System (INIS)
The neutron star matter equation of state is considered in the framework of relativistic mean-field theory, when also the scalar-isovector δ -meson effective field is taken into account. The constants of the theory are numerically determined in a way to reproduce the empirically known characteristics of symmetric nuclear matter at saturation density. The thermodynamic characteristics of both asymmetric nucleonic matter and a β -equilibrium hadron-electronic npe-plasma are studied. In the assumption that the transition to strange quark matter is a usual first order phase transition described by Maxwell's construction, the phase transition parameters changes caused by presence of δ -meson field are investigated in details. The advanced version of MIT bag model for the description of a quark phase is used, in which the interactions between quarks are taken into account in one-gluon exchange approach. The phase transition parameters for different values of bag constant in an interval B [60,120] MeV/fm3 are determined and is shown that the account of a δ -meson field results in reduction of pressure of phase transition, Po and of concentrations nN and nQ at phase transition point
Aad, G.; Abbott, B.; Abdallah, J.; Abdelalim, A. A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Acerbi, E.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Addy, T. N.; Adelman, J.; Aderholz, M.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Akiyama, A.; Alam, M. S.; Alam, M. A.; Albert, J.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allbrooke, B. M. M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alvarez Gonzalez, B.; Alviggi, M. G.; Amako, K.; Amaral, P.; Amelung, C.; Ammosov, V. V.; Amorim, A.; Amorós, G.; Amram, N.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Andrieux, M.-L.; Anduaga, X. S.; Angerami, A.; Anghinolfi, F.; Anisenkov, A.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoun, S.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Arfaoui, S.; Arguin, J.-F.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Asfandiyarov, R.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Astvatsatourov, A.; Aubert, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Avramidou, R.; Axen, D.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barashkou, A.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, V.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beale, S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, S.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Begel, M.; Behar Harpaz, S.; Behera, P. K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Ben Ami, S.; Benary, O.; Benchekroun, D.; Benchouk, C.; Bendel, M.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertella, C.; Bertin, A.; Bertinelli, F.; Bertolucci, F.; Besana, M. I.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bitenc, U.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blazek, T.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Bolnet, N. M.; Bona, M.; Bondarenko, V. G.; Bondioli, M.; Boonekamp, M.; Booth, C. N.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borri, M.; Borroni, S.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Botterill, D.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozhko, N. I.; Bozovic-Jelisavcic, I.; Bracinik, J.; Braem, A.; Branchini, P.; Brandenburg, G. W.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brelier, B.; Bremer, J.; Brenner, R.; Bressler, S.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brodbeck, T. J.; Brodet, E.; Broggi, F.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, W. K.; Brown, G.; Brown, H.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.
2012-07-01
A QCD analysis is reported of ATLAS data on inclusive W± and Z boson production in pp collisions at the LHC, jointly with ep deep-inelastic scattering data from HERA. The ATLAS data exhibit sensitivity to the light quark sea composition and magnitude at Bjorken x˜0.01. Specifically, the data support the hypothesis of a symmetric composition of the light quark sea at low x. The ratio of the strange-to-down sea quark distributions is determined to be 1.00-0.28+0.25 at absolute four-momentum transfer squared Q2=1.9GeV2 and x=0.023.
RX J1856.5-3754: A strange star with solid quark surface?
Zhang, X L; Zhang, S N
2003-01-01
Within the realms of the possibility of solid quark matter, we fitted the 500ks Chandra LETG/HRC data for RX J1856.5-3754 with a phenomenological spectral model, and found that electric conductivity of quark matter on the stellar surface is about > 1.2 x 10^{18} s^{-1}.
Quark matter symmetry energy and quark stars
Chu, Peng-Cheng; Chen, Lie-Wen
2012-01-01
We extend the confined-density-dependent-mass (CDDM) model to include isospin dependence of the equivalent quark mass. Within the confined-isospin-density-dependent-mass (CIDDM) model, we study the quark matter symmetry energy, the stability of strange quark matter, and the properties of quark stars. We find that including isospin dependence of the equivalent quark mass can significantly influence the quark matter symmetry energy as well as the properties of strange quark matter and quark sta...
Z'-induced FCNC decays of top, beauty and strange quarks
Fuyuto, Kaori; Hou, Wei-Shu; Kohda, Masaya
2015-01-01
Anomalous b --> s transitions from LHCb data may suggest a new massive gauge boson Z' that couples to the left-handed b --> s current, which in turn implies a coupling to the t --> c current. In this paper, we study flavor-changing neutral current (FCNC) decays of the top quark induced by a Z' boson, namely t --> c Z', based on a model of the gauged L_mu - L_tau symmetry (the difference between the muon and tauon numbers) with vector-like quarks, which was introduced to explain the anomalous ...
Energy Technology Data Exchange (ETDEWEB)
Airapetian, A. [Michigan Univ., Ann Arbor, MI (United States). Randall Lab. of Physics; Akopov, N.; Akopov, Z. [Yerevan Physics Institute (AR)] (and others)
2008-03-15
The momentum and helicity density distributions of the strange quark sea in the nucleon are obtained in leading order from charged-kaon production in deep-inelastic scattering on the deuteron. The distributions are extracted from spin-averaged K{sup {+-}} multiplicities, and from K{sup {+-}} and inclusive double-spin asymmetries for scattering of polarized positrons by a polarized deuterium target. The shape of the momentum distribution is softer than that of the average of the anti u and anti d quarks. (orig.)
Airapetian, A; Akopov, Z; Andrus, A; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetisian, A; Avetissian, E; Belostotskii, S; Bianchi, N; Blok, H P; Bttcher, H; Bonomo, C; Borisov, A; Brüll, A; Bryzgalov, V; Burns, J; Capiluppi, M; Capitani, G P; Cisbani, E; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; Deconinck, W; De Leo, R; Demey, M; De Nardo, L; De Sanctis, E; Diefenthaler, M; Di Nezza, P; Dreschler, J; Düren, M; Ehrenfried, M; Elalaoui-Moulay, A; Elbakian, G; Ellinghaus, F; Elschenbroich, U; Fabbri, R; Fantoni, A; Felawka, L; Frullani, S; Funel, A; Gabbert, D; Gapienko, G; Gapienko, V; Garibaldi, F; Gavrilov, G; Karibian, V; Giordano, F; Gliske, S; Gregor, I M; Guler, H; Hadjidakis, C; Hasch, D; Hasegawa, T; Hesselink, W H A; Hill, G; Hillenbrand, A; Hoek, M; Holler, Y; Hommez, B; Hristova, I; Iarygin, G; Imazu, Y; Ivanilov, A; Izotov, A; Jackson, H E; Jgoun, A; Joosten, S; Kaiser, R; Keri, T; Kinney, E; Kiselev, A; Kobayashi, T; Kopytin, M; Korotkov, V; Kozlov, V; Kravchenko, P; Krivokhizhin, V G; Lagamba, L; Lamb, R; Lapikas, L; Lehmann, I; Lenisa, P; Liebing, P; Linden-Levy, L A; Lopez Ruiz, A; Lorenzon, W; Lu, S; Lu, X R; Ma, B Q; Mahon, D; Maiheu, B; Makins, N C R; Manfr, L; Mao, Y; Marianski, B; Marukyan, H; Mexner, V; Miller, C A; Miyachi, Y; Muccifora, V; Murray, M; Mussgiller, A; Nagaitsev, A; Nappi, E; Naryshkin, Yu; Nass, A; Negodaev, M; Nowak, W D; Osborne, A; Pappalardo, L L; Perez-Benito, R; Pickert, N; Raithel, M; Reggiani, D; Reimer, P E; Reischl, A; Reolon, A R; Riedl, C; Rith, K; Rock, S E; Rosner, G; Rostomyan, A; Rubacek, L; Rubin, J; Ryckbosch, D; Salomatin, Y; Sanjiev, I; Schäfer, A; Schnell, G; Schüler, K P; Seitz, B; Shearer, C; Shibata, T A; Shutov, V; Stancari, M; Statera, M; Steffens, E; Steijger, J J M; Stenzel, H; Stewart, J; Stinzing, F; Streit, J; Tait, P; Taroian, S; Tchuiko, B; Terkulov, A; Trzcinski, A; Tytgat, M; Vandenbroucke, A; Van der Nat, P B; van der Steenhoven, G; Van Haarlem, Y; van Hulse, C; Varanda, M; Veretennikov, D; Vikhrov, V; Vilardi, I; Vogel, C; Wang, S; Yaschenko, S; Ye, H; Ye, Y; Ye, Z; Yen, S; Yu, W; Zeiler, D; Zihlmann, B; Zupranski, P
2008-01-01
The momentum and helicity density distributions of the strange quark sea in the nucleon are obtained in leading order from charged-kaon production in deep-inelastic scattering on the deuteron. The distributions are extracted from spin-averaged K+/- multiplicities, and from K+/- and inclusive double-spin asymmetries for scattering of polarized positrons by a polarized deuterium target. The shape of the momentum distribution is softer than that of the average of the ubar and dbar quarks. In the region of measurement, the helicity distribution is zero within experimental uncertainties.
Strange matter at finite temperatures
International Nuclear Information System (INIS)
The properties of strange quark matter at finite temperatures and in equilibrium with respect to weak interaction are explored on the basis of the MIT bag model picture of QCD. Furthermore, to determine the stability of strange quark matter analogous investigations are also performed for nuclear matter within Walecka's model field theory. It is found that strange quark matter can be stable at zero external pressure only for temperatures below 20 MeV. (orig.)
To Find Evidence for Strange Quark-cluster Stars with FAST
Lu, J.; Xu, R.
2016-02-01
Pulsars are not only tools for detecting nano-Hz gravitational waves and testing gravity theory, but also provide a unique test-ground for the fundamental strong interaction, the non-perturbative behavior of QCD. It is addressed here that FAST observation of radio pulsars could help us to understand the real nature of dense matter at supra-nuclear density and may finally find clear evidence for quark-cluster star.
Quenched Charmed Meson Spectra Using Tadpole Improved Quark Action on Anisotropic Lattices
Institute of Scientific and Technical Information of China (English)
LIU Liu-Ming; SU Shi-Quan; LI Xin; LIU Chuan
2005-01-01
@@ Charmed meson charmonium spectra are studied with improved quark actions on anisotropic lattices. We measured the pseudo-scalar and vector meson dispersion relations for four lowest lattice momentum modes with quark mass values ranging from the strange quark to charm quark with three different values of gauge coupling β and four different values of bare speed of light v. With the bare speed of light parameter v tuned in a mass-dependent way, we study the mass spectra of D, Ds, ηc, D*, Ds* and J/ψ mesons. The results extrapolated to the continuum limit are compared with the experiment, and a qualitative agreement is found.
Z'-induced FCNC decays of top, beauty, and strange quarks
Fuyuto, Kaori; Hou, Wei-Shu; Kohda, Masaya
2016-03-01
Anomalous b →s transitions from LHCb data may suggest a new massive gauge boson Z' that couples to the left-handed b →s current, which in turn implies a coupling to the t →c current. In this paper, we study flavor-changing neutral current (FCNC) decays of the top quark induced by a Z' boson, namely t →c Z', based on a model of the gauged Lμ-Lτ symmetry (the difference between the muon and tauon numbers) with vectorlike quarks, which was introduced to explain the anomalous LHCb data. We illustrate that searching for t →c Z' via Z'→μ+μ- with LHC Run 1 data can probe a parameter region that is unexplored by B physics for a Z' mass of around O (10 ) GeV or greater. We further extend the model to a very light Z' with mass below 400 MeV, which is motivated by the muon g -2 anomaly. Taking rare B and K meson decay data into account, we give upper limits on the t →c Z' branching ratio for the light Z' case, and discuss about its observability at the LHC. We also scrutinize the possibility that the decay KL→π0Z' with Z'→ν ν ¯ may lead to an apparent violation of the usual Grossman-Nir bound of B (KL→π0ν ν ¯)<1.4 ×10-9.
Z'-induced FCNC Decays of Top, Beauty and Strange Quarks
Fuyuto, Kaori; Kohda, Masaya
2015-01-01
Anomalous b --> s transitions from LHCb data may suggest a new massive gauge boson Z' that couples to the left-handed b --> s current, which in turn implies a coupling to the t --> c current. In this paper, we study flavor-changing neutral current (FCNC) decays of the top quark induced by a Z' boson, namely t --> c Z', based on a model of the gauged L_mu - L_tau symmetry (the difference between the muon and tauon numbers) with vector-like quarks, which was introduced to explain the anomalous LHCb data. We illustrate that searching for t --> c Z' via Z' --> mu^+ mu^- with LHC Run 1 data can already probe a parameter region which is unexplored by B physics for the Z' mass around O(10) GeV or more. We further extend the model to very light Z' with mass below 400 MeV, which is motivated by the muon g-2 anomaly. Taking rare B and K meson decay data into account, we give upper limits on the t --> c Z' branching ratio for the light Z' case, and discuss about its observability at the LHC. We also scrutinize the possi...
Energy Technology Data Exchange (ETDEWEB)
Airapetian, A. [Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109-1040 (United States); Akopov, N.; Akopov, Z. [Yerevan Physics Institute, 375036 Yerevan (Armenia); Andrus, A. [Department of Physics, University of Illinois, Urbana, IL 61801-3080 (United States); Aschenauer, E.C. [DESY, 15738 Zeuthen (Germany); Augustyniak, W. [Andrzej Soltan Institute for Nuclear Studies, 00-689 Warsaw (Poland); Avakian, R.; Avetissian, A. [Yerevan Physics Institute, 375036 Yerevan (Armenia); Avetissian, E. [Istituto Nazionale di Fisica Nucleare, Laborator i Nazionali di Frascati, 00044 Frascati (Italy); Belostotski, S. [Petersburg Nuclear Physics Institute, St. Petersburg, Gatchina, 188350 (Russian Federation); Bianchi, N. [Istituto Nazionale di Fisica Nucleare, Laborator i Nazionali di Frascati, 00044 Frascati (Italy); Blok, H.P. [Nationaal Instituut voor Kernfysica en Hoge-Energiefysica (NIKHEF), 1009 DB Amsterdam (Netherlands); Department of Physics and Astronomy, Vrije Universiteit, 1081 HV Amsterdam (Netherlands); Boettcher, H. [DESY, 15738 Zeuthen (Germany); Bonomo, C. [Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara and Dipartimento di Fisica, Universita di Ferrara, 44100 Ferrara (Italy); Borissov, A. [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Bruell, A.; Bryzgalov, V. [Institute for High Energy Physics, Protvino, Moscow region, 142281 (Russian Federation); Burns, J. [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Capiluppi, M. [Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara and Dipartimento di Fisica, Universita di Ferrara, 44100 Ferrara (Italy); Capitani, G.P. [Istituto Nazionale di Fisica Nucleare, Laborator i Nazionali di Frascati, 00044 Frascati (Italy)] (and others)
2008-09-11
The momentum and helicity density distributions of the strange quark sea in the nucleon are obtained in leading order from charged-kaon production in deep-inelastic scattering on the deuteron. The distributions are extracted from spin-averaged K{sup {+-}} multiplicities, and from K{sup {+-}} and inclusive double-spin asymmetries for scattering of polarized positrons by a polarized deuterium target. The shape of the momentum distribution is softer than that of the average of the u-bar and d-bar quarks. In the region of measurement 0.02
Energy Technology Data Exchange (ETDEWEB)
Airapetian, A.; Akopov, N.; Akopov, Z.; Andrus, A.; Aschenauer, E. C.; Jackson, H. E.; Reimer, P. E.; HERMES Collaboration; Physics; Univ. of Michigan; Yerevan Physics Inst.; Univ. of Illinois; DESY Lab.
2008-01-01
The momentum and helicity density distributions of the strange quark sea in the nucleon are obtained in leading order from charged-kaon production in deep-inelastic scattering on the deuteron. The distributions are extracted from spin-averaged K{sup {+-}} multiplicities, and from K{sup {+-}} and inclusive double-spin asymmetries for scattering of polarized positrons by a polarized deuterium target. The shape of the momentum distribution is softer than that of the average of the {bar u} and {bar d} quarks. In the region of measurement 0.02 < x < 0.6 and Q{sup 2} > 1.0 GeV{sup 2}, the helicity distribution is zero within experimental uncertainties.
Chakraborty, Bipasha; Donald, Gordon; Dowdall, Rachel; de Oliveira, Pedro Gonçalves; Koponen, Jonna; Lepage, G Peter; Teubner, T
2014-01-01
We describe a new technique (presented in arXiv:1403.1778) to determine the contribution to the anomalous magnetic moment (g-2) of the muon coming from the hadronic vacuum polarisation using lattice QCD. Our method uses Pad\\'{e} approximants to reconstruct the Adler function from its derivatives at $q^2=0$. These are obtained simply and accurately from time-moments of the vector current-current correlator at zero spatial momentum. We test the method using strange quark correlators calculated on MILC Collaboration's $n_f$ = 2+1+1 HISQ ensembles at multiple values of the lattice spacing, multiple volumes and multiple light sea quark masses (including physical pion mass configurations).
International Nuclear Information System (INIS)
A chiral model is introduced that is based on the parity doublet formulation of chiral symmetry including hyperonic degrees of freedom. The phase structure of the model is determined. Depending on the masses of the chiral partners, the transition to the chirally restored phase shows a first-order line with critical end points as a function of chemical potential and temperature in additional to the standard liquid-gas phase transition of self-bound nuclear matter. We extend the parity doublet model to describe the deconfinement phase transition which is in quantitative agreement with lattice data at μB=0. The phase diagram of the model is presented which shows a decoupling of chiral symmetry restoration and deconfinement. Loosening the constraint of strangeness conservation, we also investigate the phase diagram at net strangeness density. We calculate the strangeness per baryon fraction and the baryon-strangeness correlation factor, two quantities that are sensitive on deconfinement and that can be used to interpret lattice calculations.
Spraggs, Matt; Del Debbio, Luigi; Jüttner, Andreas; Lehner, Christoph; Maltman, Kim; Marinkovic, Marina; Portelli, Antonin
2016-01-01
We present preliminary results for the strange leading-order hadronic contribution to the anomalous magnetic moment of the muon using RBC/UKQCD physical point domain wall fermions ensembles. We discuss various analysis strategies in order to constrain the systematic uncertainty in the final result.
International Nuclear Information System (INIS)
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)
From Super-Hyper nuclei to Strange Stars
International Nuclear Information System (INIS)
Both theoretical investigations of and experimental searches for not only super-hypernuclei (or long lived hyperstrange multiquark droplets,strangelets , or strange quark matter) consisting of roughly equal numbers of up, down, and strange quarks, but also super-hypernuclear matter in bulk (or quark nuggetsor strange matter) (in the early Universe or inside neutron stars) and strange stars made of super-hypernuclear matter are reviewed and discussed in some detail
Bottom-strange mesons in hyperonic matter
Pathak, Divakar; Mishra, Amruta
2014-01-01
The in-medium behavior of bottom-strange pseudoscalar mesons in hot, isospin asymmetric and dense hadronic environment is studied using a chiral effective model. The same was recently generalized to the heavy quark sector and employed to study the behavior of open-charm and open-bottom mesons. The heavy quark (anti-quark) is treated as frozen and all medium modifications of these bottom-strange mesons are due to their strange anti-quark (quark) content. We observe a pronounced dependence of t...
A Strange Star Model for Pulsars
Xu, Ren Xin; Qiao, Guo Jun
1998-01-01
It is suggested in this paper that the `bare' strange star might be not bare, and there could be a magnetosphere around it. As a strange star might be an intensely magnetized rotator, the induced unipolar electric field would be large enough to construct a magnetosphere around the strange matter core. This kind of magnetosphere is very similar to that of the rotating magnetized neutron stars discussed by many authors. A magnetosphere will be established very soon through pair production by ga...
International Nuclear Information System (INIS)
The following questions are reviewed: classification of interactions and energy scales; quantum numbers, symmetries and laws of conservation; quarks and classification of hadrons within the context of SU4; currents and Feynmann diagrams; neutral currents and charm
A new form of strange matter and new hope for finding it.
Flam, F
1993-01-01
Scientists at Brookhaven National Laboratory and CERN in Switzerland will try to make matter from strange quarks, very elusive particles. Carl Dover of Brookhaven has theorized that strange quarks could group together into a nucleus as big as the sun.
International Nuclear Information System (INIS)
Recent experimental and theoretical advances in hypernuclear physics are reviewed. An appraisal is given of various suggestions for using strange probes to test partial quark deconfinement in nuclei and meson exchange vs quark-gluon exchange descriptions of baryon-baryon interactions. 76 refs., 6 figs
K^* Mesons and Nucleon Strangeness
Barz, L. L.; Forkel, H.; Hammer, H. -W.; Navarra, F. S.; Nielsen, M; Ramsey-Musolf, M. J.
1998-01-01
We study contributions to the nucleon strange quark vector current form factors from intermediate states containing K^* mesons. We show how these contributions may be comparable in magnitude to those made by K mesons, using methods complementary to those employed in quark model studies. We also analyze the degree of theoretical uncertainty associated with K^* contributions.
Energy Technology Data Exchange (ETDEWEB)
Batigne, G
2003-12-01
The G{sup 0} project is a parity violation experiment dedicated to the measurement of the proton weak and axial form factors by means of electron-proton scattering. Combining these weak form factors with the electromagnetic ones makes possible the extraction of the contribution of strange quarks to the charge and magnetization distribution in the nucleon. This thesis presents the strategy used for the G{sup 0} experiment, the different subsystems and the first results from its engineering run. The counting rate asymmetries, at the order of 10-5, are measured over a large range in transferred momentum (Q{sup 2} = 0.1 to 1 (GeV/c){sup 2}) with expected precision at the level of 10{sup -7}. A deadtime correction program has been developed which allows to correct 90% of the counting losses and to reduce associated false asymmetries at the level of 10-8. A method has been defined to extract the measured values of Q{sup 2} with a precision of 1%. The first preliminary results of G{sup 0} on parity violation asymmetries are also shown. (author)
Narison, Stéphan
1999-01-01
I extract the strange-quark mass using a tau-like decay sum rule for the phi-meson, and some other sum rules involving its difference with the vector component of the hadronic tau-decay. I obtain, to order alpha_s^3: m_s(1 GeV) = (188\\pm 22) MeV, which corresponds to m_s(2 GeV) = (136\\pm 16) MeV, in good agreement with the recent ALEPH result from the Delta S=-1 component of the tau-hadronic decay, and with the previous result from e+e- into hadrons data where, in the latter, a good realization of the SU(2) isospin symmetry has been assumed. The agreement of these different results signals small effects of the SU(2) violation due to the omega-rho mixing parameters in the sum rules involving the difference of the isoscalar and isovector components of the e+e- into hadrons data. This questions the reliability of the existing estimates of these parameters.
Strangeness asymmetry of the nucleon in the statistical parton model
Bourrely, Claude; Soffer, Jacques; Buccella, Franco
2007-04-01
We extend to the strange quarks and antiquarks, the statistical approach of parton distributions and we calculate the strange quark asymmetry s -sbar. We find that the asymmetry is small, positive in the low x region and negative in the high x region. In this framework, the polarized strange quarks and antiquarks distributions, which are obtained simultaneously, are found to be both negative for all x values.
Strangeness asymmetry of the nucleon in the statistical parton model
Energy Technology Data Exchange (ETDEWEB)
Bourrely, Claude [Centre de Physique Theorique, UMR 6207, Unite Mixte de Recherche du CNRS et des Universites Aix-Marseille I et Aix-Marseille II et de l' Universite du Sud Toulon-Var, Laboratoire affilie a la FRUMAM, CNRS-Luminy, Case 907, 13288 Marseille Cedex 9 (France); Soffer, Jacques [Le Zenon (A) Ave Campagne Berger, 13009 Marseille (France)]. E-mail: jacques.soffer@gmail.com; Buccella, Franco [Dipartimento di Scienze Fisiche, Universita di Napoli, Via Cintia, I-80126, Naples (Italy) and INFN, Sezione di Naples (Italy)
2007-04-26
We extend to the strange quarks and antiquarks, the statistical approach of parton distributions and we calculate the strange quark asymmetry s-s-bar. We find that the asymmetry is small, positive in the low x region and negative in the high x region. In this framework, the polarized strange quarks and antiquarks distributions, which are obtained simultaneously, are found to be both negative for all x values.
Strangeness asymmetry of the nucleon in the statistical parton model
Bourrely, Claude; Soffer, Jacques; Buccella, Franco
2007-01-01
We extend to the strange quarks and antiquarks, the statistical approach of parton distributions and we calculate the strange quark asymmetry $s-\\bar s$. We find that the asymmetry is small, positive in the low $x$ region and negative in the high $x$ region. In this framework, the polarized strange quarks and antiquarks distributions, which are obtained simultaneously, are found to be both negative for all $x$ values.
Strangeness asymmetry of the nucleon in the statistical parton model
International Nuclear Information System (INIS)
We extend to the strange quarks and antiquarks, the statistical approach of parton distributions and we calculate the strange quark asymmetry s-s-bar. We find that the asymmetry is small, positive in the low x region and negative in the high x region. In this framework, the polarized strange quarks and antiquarks distributions, which are obtained simultaneously, are found to be both negative for all x values
Exotic mesons with JPC=1-+, strange and non-strange
International Nuclear Information System (INIS)
We analyse the QCD sum rules for the exotic quark-antiquark-gluon states called ''glukonium'' or ''hermaphrodite'' mesons. We predict a non-strange resonance of this type at ∝1.5 GeV, a strange one at ∝1.6 GeV and a strange-antistrange one at ∝1.75 GeV. It should be noted that the above values of masses depend crucially on the vacuum expectation value of the gluon field operator 3fabc.GaμνGbνλGcλμ>. (orig.)
Institute of Scientific and Technical Information of China (English)
HOU Hong-Sheng; SUN Hao; ZHOU Ya-Jin
2013-01-01
Flavor changing effects on the processes t → ch,e+e-→ b-s,e+e-→ b-sh and pp → b-s in the LHT model are investigated in this paper.We calculate the one-loop level contributions from the T-parity odd mirror fermions and gauge bosons.The results show that the top quark rare decay t → ch in the LHT model can be significantly enhanced relative to that in the SM.The b-s production at linear colliders in the LHT model can enhance the SM cross section a lot and reach 0.1 Fb in some parameter space allowed in the experiment.But the heavy gauge boson and mirror fermion loops have small contribution to the processes pp → b-s and e+e-→ b-sh.So the LHT effect on e+e-→ b-s might be detected at future linear colliders,while it is too small to be seen for the e+ e-→ b-sh and pp → b-s processes at future linear colliders and LHC.
Lian-Rong, Dai; Zong-Ye, Zhang; You-Wen, Yu
2006-01-01
The structure of $(\\Omega\\Omega)_{0^+}$ dibaryon with strangeness $s=-6$ is studied in the extended chiral SU(3) quark model, in which vector meson exchange dominates the short range interaction. The resonating group method (RGM) is adopted, in which the $\\Omega\\Omega$ and $CC$ (hidden color) channels are involved. The color screening effect and the effects of mixing of scalar mesons on $(\\Omega\\Omega)_{0^+}$ are also investigated.
International Nuclear Information System (INIS)
This report is a compilation of papers reflecting current trends in non-accelerator particle physics, corresponding to talks that its author was invited to present at the Workshop on Tibet Cosmic Ray Experiment and Related Physics Topics held in Beijing, China, April 4--13, 1995. The papers are entitled 'Neutrino Mass and Oscillation', 'High Energy Neutrino Astrophysics', 'Detection of Dark Matter', 'Search for Strange Quark Matter', and 'Magnetic Monopole Searches'. The report is introduced by a survey of the field and a brief description of each of the author's papers
Energy Technology Data Exchange (ETDEWEB)
He, Yudong [California Univ., Berkeley, CA (United States)]|[Lawrence Berkeley Lab., CA (United States)
1995-07-01
This report is a compilation of papers reflecting current trends in non-accelerator particle physics, corresponding to talks that its author was invited to present at the Workshop on Tibet Cosmic Ray Experiment and Related Physics Topics held in Beijing, China, April 4--13, 1995. The papers are entitled `Neutrino Mass and Oscillation`, `High Energy Neutrino Astrophysics`, `Detection of Dark Matter`, `Search for Strange Quark Matter`, and `Magnetic Monopole Searches`. The report is introduced by a survey of the field and a brief description of each of the author`s papers.
A Scaling Law for Quark Masses
Fritzsch, Harald; Özer, Alp Deniz
2004-01-01
We show that the observed quark masses seem to be consistent with a simple scaling law. Due to the precise values of the heavy quarks we are able to calculate the quark masses in the light quark sector. We discuss a possible value for the strange quark mass. We show that the u-type quark masses obey the scaling law very well.
Hadron spectroscopy from strangeness to charm and beauty
International Nuclear Information System (INIS)
Quarks of different flavors have different masses, which will cause breaking of flavor symmetries of QCD. Flavor symmetries and their breaking in hadron spectroscopy play important role for understanding the internal structures of hadrons. Hadron spectroscopy with strangeness reveals the importance of unquenched quark dynamics. Systematic study of hadron spectroscopy with strange, charm and beauty quarks would be very revealing and essential for understanding the internal structure of hadrons and its underlying quark dynamics
Hadron spectroscopy from strangeness to charm and beauty
Energy Technology Data Exchange (ETDEWEB)
Zou, B.S., E-mail: zoubs@ihep.ac.cn [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, Beijing 100049 (China)
2013-09-20
Quarks of different flavors have different masses, which will cause breaking of flavor symmetries of QCD. Flavor symmetries and their breaking in hadron spectroscopy play important role for understanding the internal structures of hadrons. Hadron spectroscopy with strangeness reveals the importance of unquenched quark dynamics. Systematic study of hadron spectroscopy with strange, charm and beauty quarks would be very revealing and essential for understanding the internal structure of hadrons and its underlying quark dynamics.
Hadron spectroscopy from strangeness to charm and beauty
Zou, B. S.
2013-09-01
Quarks of different flavors have different masses, which will cause breaking of flavor symmetries of QCD. Flavor symmetries and their breaking in hadron spectroscopy play important role for understanding the internal structures of hadrons. Hadron spectroscopy with strangeness reveals the importance of unquenched quark dynamics. Systematic study of hadron spectroscopy with strange, charm and beauty quarks would be very revealing and essential for understanding the internal structure of hadrons and its underlying quark dynamics.
Energy Technology Data Exchange (ETDEWEB)
Guillon, B
2005-10-15
In the framework of the Quantum Chromodynamics (QCD), the nucleon is described as being composed of three valence quarks surrounded by a sea of virtual quark-antiquark pairs and gluons. If the role of this virtual sea in the nucleon properties is inferred to be important, this contribution is still poorly understood. In this context, we study the role of the strange quarks in the nucleon since this is the lightest quark flavor of the sea with no valence contribution. We are determining its contribution to the charge and magnetization distributions in the nucleon via parity violation experiments. The measurement is performed by elastically scattering polarized electrons from nucleon target. A world wide program in which the G0 experiment takes place has been performing for a decade. The G0 experiment and the analysis of the results from its forward angles phase are the topics of this thesis. This document presents the physics case of the strangeness content of the nucleon (mass, spin, impulsion). It describes also the formalism related to the electroweak probe and the form factors, and then the principle of parity violating asymmetry measurement. The G0 experimental setup, which was built and installed in the Hall C of the Jefferson Laboratory (Usa), is detailed. This set-up was designed for the measurement of asymmetries of the order of 10{sup -6} with an overall relative uncertainty better than 10 %, over a momentum transfer range 0.1-1 (GeV/c){sup 2}. The various steps of the data analysis are exposed. They have allowed us to start from measured counting rates to reach parity violating physics asymmetries. This required a careful treatment of the various sources of systematical errors which is discussed extensively. Finally the results from the G0 forward angle measurement, its comparison with others experiments and with theoretical models, are presented. They support a non null strange quark contribution. (author)
International Nuclear Information System (INIS)
Precision measurements of the weak force suggest that strange quarks have an influence on the magnetic moment of the proton, as Krishna Kumar explains. In the 1980s experiments performed by the European Muon Collaboration at CERN showed that the spin of the proton - that is its intrinsic angular momentum - could not be explained by simply adding together the spins of its constituent quarks (which have a magnitude of 1/2 in units of Planck's constant). Instead, researchers found that 'up' and 'down' quarks contributed less than 25% to the spin of the proton (which also has a magnitude of 1/2). It has long been thought that the presence of strange quarks inside the proton might partly explain this 'spin crisis'. These quarks, which are heavier than up and down quarks, are typically observed only in high-energy cosmic rays or particle accelerators, not in the everyday nuclei that make up the world around us. However, the force that holds the quarks together inside protons and other particles is so strong that the uncertainty principle allows quark-antiquark pairs to spontaneously appear from the vacuum and then disappear a short time later. The question is, do these ephemeral 'sea quarks' contribute to the observed properties of the proton, such as its mass, charge, spin and magnetic moment? A series of experimental results, most recently from the Jefferson Laboratory in the US, now seems poised to provide a definitive answer to this question. (U.K.)
Strangeness exchange reactions and hypernuclei
International Nuclear Information System (INIS)
Recent progress in the spectroscopy of Λ and Σ hypernuclei is reviewed. Prospects for the production of doubly strange hypernuclei at a future kaon factory are assessed. It is suggested that the (K-,K+) reaction on a nuclear target may afford an optimal way of producing the H dibaryon, a stable six quark object with J/sup π/ = O+, S = -2
Evidence against a strange ground state for baryons
International Nuclear Information System (INIS)
We argue that if strange quark matter were the ground state of baryons at zero pressure and if some observed compact stars (or some cosmic rays) are strange, then the interstellar medium is so contaminated by strangelets that essentially all 'neutron' stars in the disk of the galaxy could have to be quark stars: Strangelet contamination would apparently vastly exceed the minimum abundance needed to seed all newly born neutron stars. Because observed glitches seem not to be compatible with quark stars, a strange quark ground state is unlikely. (orig.)
Quark mass dependence of H-dibaryon
Yamaguchi, Yasuhiro
2016-01-01
The H-dibaryon is the exotic multiquark state with baryon number 2 and strangeness $-2$. The existence of the deeply bound H-dibaryon is excluded by the observation of the double hypernuclei. However the recent Lattice QCD simulations have found the bound state below the $\\Lambda\\Lambda$ threshold with large quark masses by HALQCD and NPLQCD collaborations. In this talk, the quark mass dependence of the H-dibaryon mass is discussed using the pionless effective field theory (EFT) where a bare H-dibaryon field is coupled with two-baryon states. We determine the parameters in this theory by fitting the recent Lattice QCD results in the SU(3) limit. As a result, we obtain the attractive scattering length at the physical point where the H-dibaryon is unbound.
Color Superconducting Quark Matter in Neutron Stars
Heiselberg, H.
1999-01-01
Color superconductivity in quark matter is studied for electrically charge neutral neutron star matter in $\\beta$-equilibrium. Both bulk quark matter and mixed phases of quark and nuclear matter are treated. The electron chemical potential and strange quark mass affect the various quark chemical potentials and therefore also the color superconductivity due to dicolor pairing or color-flavor locking.
Energy Technology Data Exchange (ETDEWEB)
El Yakoubi, M.A
2007-03-15
The PVA4 experiment (Parity Violating in hall A4 in Mainz) aims at assessing the contribution of the strange quark to the charge and current distributions in the nucleon. In order to determine these distributions, measurements of the elastic scattering of longitudinal polarized electrons on a hydrogen target have been performed. 2 types of interaction are involved in this experiment: the electromagnetic interaction (virtual photon exchange) that dominates, and the weak interaction (neutral Z{sup 0} boson exchange). The non-conservation of the parity in the weak interaction induces an asymmetry in the counting rate according to the helicity of the electron beam. The difficulty of this experiment is that it requires the control of the systematic errors and the recording of high statistics due to the low asymmetry (about 10{sup -5} and 10{sup -6} according to the transferred momentum). This document presents the first Rosenbluth separation specific to the PVA4 at Q = 0.23 GeV/c{sup 2}. A formalism related to the violation of parity to separate the strange form factors is developed. The PVA4 experimental setup dedicated to the experiment is given, as well as the Monte-Carlo technique used to extract the strange quark contribution is detailed. The data analysis at forwards and backwards angles has enabled us to determine the following asymmetry values of parity violation: (-5.44 {+-} 0.54 (stat) {+-} 0.26 (sys)) ppm forwards and (-17.1 {+-} 1.4 (stat)) ppm backwards. The combining of these asymmetry values at Q = 0.23 GeV/c{sup 2} has led to the determination of the strange form factors G{sub E}{sup s} and G{sub M}{sup s}: G{sub E}{sup s} = (0.047 {+-} 0.041) and G{sub M}{sup s} = (-0.052 {+-} 0.164). It is also shown that while the strange quark electric component is compatible with a null value, a non-zero contribution of the magnetic part is possible.
Nucleon Strangeness and Unitarity
Musolf, M. J.; Hammer, H. -W.; D. Drechsel(Institut f. Kernphysik, Mainz)
1996-01-01
The strange-quark vector current form factors of the nucleon are analyzed within the framework of dispersion relations. Particular attention is paid to contributions made by $K\\bar{K}$ intermediate states to the form factor spectral functions. It is shown that, when the $K\\bar{K}\\to N\\bar{N}$ amplitude is evaluated in the Born approximation, the $K\\bar{K}$ contributions are identical to those arising from a one-loop calculation and entail a serious violation of unitarity. The mean square stra...
Bottom-strange mesons in hyperonic matter
Pathak, Divakar
2014-01-01
The in-medium behavior of bottom-strange pseudoscalar mesons in hot, isospin asymmetric and dense hadronic environment is studied using a chiral effective model. The same was recently generalized to the heavy quark sector and employed to study the behavior of open-charm and open-bottom mesons. The heavy quark (anti-quark) is treated as frozen and all medium modifications of these bottom-strange mesons are due to their strange anti-quark (quark) content. We observe a pronounced dependence of their medium mass on baryonic density and strangeness content of the medium. Certain aspects of these in-medium interactions are similar to those observed for the strange-charmed mesons in a preceding investigation, such as the lifting of mass-degeneracy of $B_S^0$ and ${\\bar B}_S^0$ mesons in hyperonic matter, while the same is respected in vacuum as well as in nuclear matter. In general, however, there is a remarkable distinction between the two species, even though the formalism predicts a completely analogous in-medium...
Energy Technology Data Exchange (ETDEWEB)
El Yakoubi, Marouan Abdelbaste [Universite de Paris XI, Paris (France)
2007-07-01
Quantum Chromodynamics describes the proton as three valence quarks surrounded by a sea of quark-antiquark pairs and gluons.The purpose of an international program, which the PVA4 experiment takes part, is to quantify the contribution of the strange quark to the charge and current distributions in the nucleon. Experimentally, to determine these distributions measurements of elastic scattering of longitudinally polarized electrons ///on a hydrogen target are performed. Two types of interactions intervene in these experiments: the electromagnetic interaction (virtual photon exchange) which dominates, and the weak interaction (neutral boson Z{sup 0} exchange). The non-conservation of parity in the weak interaction induces an asymmetry in the counting rate according to the helicity of the electron beam. The difficulty of these experiments is that they require to control the systematic errors and to record high statistics due to the low asymmetry (about 10{sup -5} and 10{sup -6} according to the transferred momentum). This document presents the first Rosenbluth separation specific to the PVA4 at Q{sup 2} = 0.23(GeV/c){sup 2}. A formalism related to the violation of parity to separate the strange form factors is developed. The PVA4 experimental setup dedicated to the measurement is given, as well as the Monte Carlo technique used to extract the strange quark contribution is detailed. The results of the analysis are presented, and show that while the strange quark electric component is compatible with a null value, a nonzero contribution of magnetic part is possible. (author)
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.'
Rafelski, Johann
1998-01-01
We present a brief survey of the development of nuclear physics towards relativistic quark physics. This is followed by a thorough discussion of the quest for the observation of the dissolution of nuclear matter into the deconfined quark matter (QGP) in relativistic nuclear collisions. Use of strange particle signatures in search for QGP is emphasized.
The role of strangeness in the nucleon structure
International Nuclear Information System (INIS)
It is shown that by reformulating an SU(3) Skyrmion model as a random phase approximation (RPA) to an underlying fermion (quark) theory, one can calculate microscopic (quark) properties of the nucleon without explicit account of the quark-gluon degrees of freedom. In particular, the strangeness content of the proton can be estimated with a Skyrmion model that describes well the hyperon spectroscopy
Czech Academy of Sciences Publication Activity Database
Aad, G.; Abbott, B.; Abdallah, J.; Chudoba, Jiří; Gallus, Petr; Gunther, Jaroslav; Hruška, I.; Juránek, Vojtěch; Kepka, Oldřich; Kupčo, Alexander; Kůs, Vlastimil; Lokajíček, Miloš; Marčišovský, Michal; Mikeštíková, Marcela; Myška, Miroslav; Němeček, Stanislav; Panušková, M.; Růžička, Pavel; Schovancová, Jaroslava; Šícho, Petr; Staroba, Pavel; Svatoš, Michal; Taševský, Marek; Tic, Tomáš; Valenta, J.; Vrba, Václav; Zeman, Martin
2012-01-01
Roč. 109, č. 1 (2012), "012001-1"-"012001-18". ISSN 0031-9007 R&D Projects: GA MŠk LA08032 Institutional research plan: CEZ:AV0Z10100502 Keywords : ATLAS * LHC * sea quark * quark density, * Z0 hadronproduction * deep inelastic scattering * QCD * parton distribution function Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 7.943, year: 2012 http://arxiv.org/abs/arXiv:1203.4051
Strange anti-baryons---QGP versus HC
International Nuclear Information System (INIS)
We study quark-gluon plasma (QGP) and hadronic gas (HG) models of the central fireball presumed to be the source of abundantly produced strange (anti-)baryons in S→W collisions at 200 GeV A. We consider how multi-strange (anti-)baryon multiplicities depend on strangeness conservation and compare the HG and QGP fireball scenarios. We argue that the total particle multiplicity emerging from the central rapidity region as well as the variation of production rates with changes in the beam energy allows to distinguish between the two reaction scenarios
International Nuclear Information System (INIS)
The A4 collaboration at the MAMI accelerator facility in Mainz investigates the structure of the proton by elastic scattering of polarized electrons off unpolarized hydrogen. At longitudinal polarization there is a parity violating asymmetry in the cross section which gives information about the contribution of strangeness to the vector form factor of the proton. At transverse polarization there are azimuthal asymmetries, which arise from the contribution of two-photon exchange to the cross section and allow access to the imaginary part of the two-photon amplitude. Within the scope of this thesis, measurements have been made and analyzed at two momentum transfers both with longitudinal and transverse polarization. The main emphasis has been placed on the extraction of the raw asymmetries out of the data, the corrections of the raw asymmetries for false asymmetries, the estimation of the systematic errors and the determination of the strange form factors out of the parity violating asymmetries. For the measurements at longitudinal polarization, the asymmetries have been determined to A=(-5.59±0.57stat±0.29syst) ppm at Q2=0.23 (GeV/c)2 and A=(-1.39±0.29stat±0.12syst) ppm at Q2=0.11 (GeV/c)2. The linear combination of the strange form factors have been evaluated to GEs+0.225GMs=0.029±0.034 and GEs+0.106GMs=0.070±0.035 respectively. Both results are in agreement with other experiments and suggest a nonvanishing contribution of strangeness to the form factors. For the measurements at transverse polarization the normal spin asymmetries have been determined to A=(-8.51±2.31stat±089syst) ppm at E=855 MeV and Q2=0.23 (GeV/c2) and to A=(-8.59±0.89stat±0.83syst) ppm at E=569 MeV and Q2=0.11 (GeV/c)2. The size of the asymmetries prove that not only the ground state of the proton but also excited states contribute to the intermediate hadronic state. (Orig.)
K meson-nucleus interactions: strangeness and nuclear matter
International Nuclear Information System (INIS)
A brief review is provided of some straightforward K-nuclear and Λ-hypernuclear systems. A discussion of less straightforward speculations on H-dibaryons and strange quark matter by many authors, is also given. 28 refs., 6 figs
The Discovery of the Top Quark
Sinervo, P.K.
1995-12-01
The top quark and the Higgs boson are the heaviest elementary particles predicted by the standard model. The four lightest quark flavours, the up, down, strange and charm quarks, were well-established by the mid-1970's. The discovery in 1977 of the {Tau} resonances, a new family of massive hadrons, required the introduction of the fifth quark flavour. Experimental and theoretical studies have indicated that this quark also has a heavier partner, the top quark.
Measurement of strange-quark contributions to the nucleon's form factors at Q(2) = 0.230 (GeV/c)(2).
Maas, F E; Achenbach, P; Aulenbacher, K; Baunack, S; Capozza, L; Diefenbach, J; Grimm, K; Imai, Y; Hammel, T; von Harrach, D; Kabuss, E M; Kothe, R; Lee, J H; Lorente, A; Lopes Ginja, A; Nungesser, L; Schilling, E; Stephan, G; Weinrich, C; Altarev, I; Arvieux, J; Collin, B; Frascaria, R; Guidal, M; Kunne, R; Marchand, D; Morlet, M; Ong, S; van de Wiele, J; Kowalski, S; Plaster, B; Suleiman, R; Taylor, S
2004-07-01
We report on a measurement of the parity-violating asymmetry in the scattering of longitudinally polarized electrons on unpolarized protons at a Q2 of 0.230 (GeV/c)(2) and a scattering angle of theta (e) = 30 degrees - 40 degrees. Using a large acceptance fast PbF2 calorimeter with a solid angle of delta omega = 0.62 sr, the A4 experiment is the first parity violation experiment to count individual scattering events. The measured asymmetry is A(phys)=(-5.44+/-0.54(stat)+/-0.26(sys))x10(-6). The standard model expectation assuming no strangeness contributions to the vector form factors is A(0) = (-6.30+/-0.43) x 10(-6). The difference is a direct measurement of the strangeness contribution to the vector form factors of the proton. The extracted value is G(s)(E) + 0.225G(s)(M) = 0.039+/-0.034 or F(s)(1) + 0.130F(s)(2) = 0.032+/-0.028. PMID:15323904
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)
Quark spin and quark orbital angular momentum content of the proton
Energy Technology Data Exchange (ETDEWEB)
Li, B.A. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506 (United States)
1995-09-01
In a quark-meson theory it is found that the smallness of quark spin content and strong strange quark polarization can be understood by the anomaly and large {ital N}{sub {ital c}} expansion very well. It has been proved in this theory that the proton spin is mostly carried by quark orbital angular momentum. {copyright} {ital 1995 American Institute of Physics.}
Is SAX J1808.4-3658 A Strange Star?
Li, X D; Dey, M; Dey, J; Van den Heuvel, E P J; Dey, Mira; Dey, Jishnu
1999-01-01
One of the most important questions in the study of compact objects is the nature of pulsars, including whether they are composed of $\\beta$-stable nuclear matter or strange quark matter. Observations of the newly discovered millisecond X-ray pulsar \\sax with the Rossi X-Ray Timing Explorer place firm constraint on the radius of the compact star. Comparing the mass - radius relation of \\sax with the theoretical mass - radius relation for neutron stars and for strange stars, we find that a strange star model is more consistent with \\sax, and suggest that it is a likely strange star candidate.
Heavy quarks and CP: Moriond 1985
International Nuclear Information System (INIS)
The presentations at the Fifth Moriond Workshop on Heavy Quarks, Flavor Mixing, and CP Violation (La Plagne, France, January 13-19, 1985) are summarized. The following topics are reviewed. What's New (beyond the top, top quarks, bottom quarks, charm quarks, strange quarks, and others); why is all this being done (strong interactions and hadron structure, and electroweak properties); and what next (facilities and can one see CP violation in the B-anti B system). 64 refs., 10 figs
Spectrum of hadrons with strangeness
Chen, Chen; Roberts, Craig D; Wan, Shaolong; Wilson, David J
2012-01-01
We describe a calculation of the spectrum of strange and nonstrange hadrons that simultaneously correlates the dressed-quark-core masses of meson and baryon ground- and excited-states within a single framework. The foundation for this analysis is a symmetry-preserving Dyson-Schwinger equation treatment of a vector-vector contact interaction. Our results exemplify and highlight the deep impact of dynamical chiral symmetry breaking on the hadron spectrum: an accurate description of the meson spectrum entails a similarly successful prediction of the spectrum of baryons, including those with strangeness. The analysis also provides numerous insights into baryon structure. For example, that baryon structure is largely flavour-blind, the first radial excitation of ground-state baryons is constituted almost entirely from axial-vector diquark correlations, and DCSB is the foundation for the ordering of low-lying baryon levels; viz., (1/2)^+, (1/2)^+, (1/2)^-.
Hyperon polarization in the constituent quark model
International Nuclear Information System (INIS)
A mechanism for hyperon polarization in the inclusive production is considered. The main role belongs to the orbital angular momentum and polarization of strange quark-antiquark pairs in the internal structure of constituent quarks. The nonperturbative hadron structure is based on the results of chiral quark models
Melting hadrons, boiling quarks
Energy Technology Data Exchange (ETDEWEB)
Rafelski, Johann [CERN-PH/TH, Geneva 23 (Switzerland); The University of Arizona, Department of Physics, Tucson, Arizona (United States)
2015-09-15
In the context of the Hagedorn temperature half-centenary I describe our understanding of the hot phases of hadronic matter both below and above the Hagedorn temperature. The first part of the review addresses many frequently posed questions about properties of hadronic matter in different phases, phase transition and the exploration of quark-gluon plasma (QGP). The historical context of the discovery of QGP is shown and the role of strangeness and strange antibaryon signature of QGP illustrated. In the second part I discuss the corresponding theoretical ideas and show how experimental results can be used to describe the properties of QGP at hadronization. The material of this review is complemented by two early and unpublished reports containing the prediction of the different forms of hadron matter, and of the formation of QGP in relativistic heavy ion collisions, including the discussion of strangeness, and in particular strange antibaryon signature of QGP. (orig.)
Melting Hadrons, Boiling Quarks
Rafelski, Johann
2015-01-01
In the context of the Hagedorn temperature half-centenary I describe our understanding of the hot phases of hadronic matter both below and above the Hagedorn temperature. The first part of the review addresses many frequently posed questions about properties of hadronic matter in different phases, phase transition and the exploration of quark-gluon plasma (QGP). The historical context of the discovery of QGP is shown and the role of strangeness and strange antibaryon signature of QGP illustrated. In the second part I discuss the corresponding theoretical ideas and show how experimental results can be used to describe the properties of QGP at hadronization. Finally in two appendices I present previously unpublished reports describing the early prediction of the different forms of hadron matter and of the formation of QGP in relativistic heavy ion collisions, including the initial prediction of strangeness and in particular strange antibaryon signature of QGP.
Some analytical models of anisotropic strange stars
Murad, Mohammad Hassan
2016-01-01
Over the years of the concept of local isotropy has become a too stringent condition in modeling relativistic self-gravitating objects. Taking local anisotropy into consideration, in this work, some analytical models of relativistic anisotropic charged strange stars have been developed. The Einstein-Maxwell gravitational field equations have been solved with a particular form of one of the metric potentials. The radial pressure and the energy density have been assumed to follow the usual linear equation of state of strange quark matter, the MIT bag model.
KN Scattering and the Nucleon Strangeness Radius
Ramsey-Musolf, M. J.; Hammer, H. -W.
1997-01-01
The leading non-zero electric moment of the nucleon strange-quark vector current is the mean square strangeness radius, $$. We evaluate the lightest OZI-allowed contribution to $$, arising from the kaon cloud, using dispersion relations. Drawing upon unitarity constraints as well as $K^{+}N$ scattering and $e^+e^-\\to K\\bar{K}$ cross section data, we find the structure of this contribution differs significantly from that suggested by a variety of QCD-inspired model calculations. In particular,...
Quark Masses and Renormalization Constants from Quark Propagator and 3-point Functions
Becirevic, D.; Lubicz, V.; Martinelli, G.; Testa, M.(INFN Laboratori Nazionali di Frascati, Frascati, Italy)
1999-01-01
We have computed the light and strange quark masses and the renormalization constants of the quark bilinear operators, by studying the large-p^2 behaviour of the lattice quark propagator and 3-point functions. The calculation is non-perturbatively improved, at O(a), in the chiral limit. The method used to compute the quark masses has never been applied so far, and it does not require an explicit determination of the quark mass renormalization constant.
Physics of the nucleon sea quark distributions
Energy Technology Data Exchange (ETDEWEB)
Vogt, R.
2000-03-10
Sea quark distributions in the nucleon have naively been expected to be generated perturbatively by gluon splitting. In this case, there is no reason for the light quark and anti-quark sea distributions to be different. No asymmetries in the strange or heavy quark sea distributions are predicted in the improved parton model. However,recent experiments have called these naive expectations into question. A violation of the Gottfried sum rule has been measured in several experiments, suggesting that (bar u) < (bar d) in the proton. Additionally, other measurements, while not definitive, show that there may be an asymmetry in the strange and anti-strange quark sea distributions. These effects may require nonperturbative explanations. In this review we first discuss the perturbative aspects of the sea quark distributions. We then describe the experiments that could point to nonperturbative contributions to the nucleon sea. Current phenomenological models that could explain some of these effects are reviewed.
Some Aspects of Strange Matter in Astrophysics
Banerjee, Shibaji
2014-01-01
The present work is connected with the investigation of the origin and properties of compact astrophysical objects endowed with strangeness, with the objective of finding out their relevance in the formation and evolution of the universe. In the first part of the thesis, Chap.~1-3, we discuss a model, proposed by us, to describe the propagation of small lumps of Strange Quark Matter (SQM) or strangelets, through the Terrestrial atmosphere. The theoretical results were found to be well correlated with exotic cosmic ray events characterized by very low charge to mass ratio. In the next part, we have investigated the other end of the mass spectrum of SQM. In Chap 5, we have developed an analytical expression for the Chandrasekhar Limit of Strange Quark Stars. The limit is found to depend on the fundamental constants (including the bag constant). In the last chapter we have endeavored to show that the quark nuggets, surviving the quark-hadron phase transition in the millisecond era of the early Universe can provi...
Carinhas, P A
1993-01-01
Typical nuclear equations of state and a quark bag model, surprisingly, allow compact stars with alternate layers of neutrons and quarks. One can determine on the basis of the Gibbs free energy which phase, nuclear or quark, is energetically favorable. Using the nuclear equation of state of Wiringa, and a quark equation of state given by Freedman and McLerran, the allowed quark parameter space for such layer stars is searched. This paper differs from past work in that configurations are found in which quark matter is located exterior and interior to shells of nuclear matter, i.e., dependent on quark parameters, a star may contain several alternating layers of quark and nuclear matter. Given the uncertainty in the quark parameter space, one can estimate the probability for finding pure neutron stars, pure quark stars (strange stars), stars with a quark core and a nucleon exterior, or layer stars. Several layer models are presented. The physical characteristics, stability, and results of a thorough search of th...
Strange and Non-Strange Meson Fluctuations off the Nambu--Jona-Lasinio Soliton
Weigel, H; Alkofer, R
1993-01-01
Mesonic fluctuations off the chiral soliton of the Nambu--Jona-Lasinio model are investigated. The hedgehog configuration is proven to represent a local extremum of the action. The method is applied to flavor SU(3) and the energy eigenvalue of the kaon bound state in the soliton background is evaluated which is the key ingredient for the Callan-Klebanov approach to hyperons. The energy eigenvalue of the corresponding strange-valence-quark is found to be 183MeV higher than the energy eigenvalue of the up-valence-quark when 400MeV is assumed for the up-quark constituent mass.
Tolos, Laura; Khemchandani, Kanchan; Martinez-Torres, Alberto; Bratkovskaya, Elena; Aichelin, Joerg; Nielsen, Marina; Navarra, Fernando S
2015-01-01
We study the properties of strange mesons in vacuum and in the hot nuclear medium within unitarized coupled-channel effective theories. We determine transition probabilities, cross sections and scattering lengths for strange mesons. These scattering observables are of fundamental importance for understanding the dynamics of strangeness production and propagation in heavy-ion collisions.
Strangeness in the baryon ground states
Semke, A
2012-01-01
We compute the strangeness content of the baryon ground states based on an analysis of recent lattice simulations of the BMW, PACS, LHPC and HSC groups for the pion-mass dependence of the baryon masses. Our results rely on the relativistic chiral Lagrangian and large-$N_c$ sum rule estimates of the counter terms relevant for the baryon masses at N$^3$LO. A partial summation is implied by the use of physical baryon and meson masses in the one-loop contributions to the baryon self energies. A simultaneous description of the lattice results of the BMW, LHPC, PACS and HSC groups is achieved. We predict the pion- and strangeness sigma terms and the pion-mass dependence of the octet and decuplet ground states at different strange quark masses.
Strangeness production in pp-bar collision
International Nuclear Information System (INIS)
We study strangeness production reactions in the framework of a Chiral Constituent Quark Model. The model includes the coupling with the SU(3) pseudoscalar meson octet due to the spontaneous chiral symmetry breaking. It also includes QCD perturbative effects through the coupling with the gluon field. In this way the two traditional mechanism of strangeness production, i.e., the kaon exchange and gluon annihilation, are introduce in the same framework. Two meson exchanges are parametrized through the exchange of scalar mesons, namely a sigma and a kappa exchange. The kappa exchange allows a better description of the polarization observables of the pp-bar →ΛΛ-bar production reaction. Other strangeness production reaction in the isospin 1 sector are also studied.
Color superconductivity and quark stars
International Nuclear Information System (INIS)
The search for new phases of strange quark matter inside neutron stars has recently received a lot of attention since it has been shown that the attractive nature of the one gluon exchange interaction in QCD may produce a superconducting phase in quark matter. We study an extended version of the Chromodielectric model with a BCS quark pairing implemented, and analyze the superconducting color flavor locked phase. We show that the inclusion in the free energy density of a negative term of the diquark condensate ensures the stability of quark matter. We explore the implications of our results in the structure of compact quark stars and explicitly show that CFL stars can be absolutely stable and more compact than strange stars
Color superconductivity and quark stars
Energy Technology Data Exchange (ETDEWEB)
Malheiro, M. [Instituto Tecnologico de Aeronautica, CTA, 12-228-900, Sao Jose dos Campos (Brazil); Instituto de Fisica, Universidade Federal Fluminense, 24-210-320, Niteroi (Brazil); Linares, L.P. [Instituto de Fisica, Universidade Federal Fluminense, 24-210-320, Niteroi (Brazil); Fiolhais, M. [Departamento de Fisica, Centro de Fisica Computacional, Universidade de Coimbra, P-3004-516 Coimbra (Portugal); Taurines, A. [Department of Physics, University of Wales Swansea, Singleton Park, Swansea, SA2 8PP (United Kingdom)
2007-06-15
The search for new phases of strange quark matter inside neutron stars has recently received a lot of attention since it has been shown that the attractive nature of the one gluon exchange interaction in QCD may produce a superconducting phase in quark matter. We study an extended version of the Chromodielectric model with a BCS quark pairing implemented, and analyze the superconducting color flavor locked phase. We show that the inclusion in the free energy density of a negative term of the diquark condensate ensures the stability of quark matter. We explore the implications of our results in the structure of compact quark stars and explicitly show that CFL stars can be absolutely stable and more compact than strange stars.
Walsh, Karen McNulty
2011-03-28
Near-light-speed collisions of gold ions provide a recipe for in-depth explorations of matter and fundamental forces. The Relativistic Heavy Ion Collider (RHIC) has produced the most massive antimatter nucleus ever discovered—and the first containing an anti-strange quark. The presence of strange antimatter makes this antinucleus the first to be entered below the plane of the classic Periodic Table of Elements, marking a new frontier in physics.
A new form of strange matter and new hope for finding it
International Nuclear Information System (INIS)
Deep in the dense cores of collapsed stars even atoms don't survive. The force of gravity crushes them into particle mushes weighing megatons per teaspoon. But even these alien forms of matter don't hold a candle to another possible end product of a collapsing star: something physicists justifiably call strange matter. This strangeness comes from an exotic particle not associated with ordinary matter: the strange quark. It belongs to a six-member quark family, along with up, down, charm, top, and bottom, each of which carries a different combination of charge and mass. The only ones that make up matter as we know it are up and down quarks, but in theory, matter could form out of strange quarks as well. In nature, it would turn up most probably in interiors of collapsed stars. Scientists originally imagined strange matter as a sort of disorganized mixed bag of strange quarks, but this summer a group proposed that the quarks could form a sort of mutant atomic nucleus that could conceivably grow to the size of a star. For the moment this is speculation, but it may not be theoretical musing for long. Physicists are preparing to try making strange matter here on Earth, in experiments at Brookhaven National Laboratory in New York and Switzerland's CERN, next summer
Rapidity dependence of strangeness enhancement factor at FAIR energies
International Nuclear Information System (INIS)
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
The Scalar Strange Content of the Nucleon from Lattice QCD
Junnarkar, Parikshit
2013-01-01
The scalar strange-quark matrix element of the nucleon is computed with lattice QCD. A mixed-action scheme is used with domain-wall valence fermions computed on the staggered MILC sea-quark configurations. The matrix element is determined by making use of the Feynman-Hellmann Theorem which relates this strange matrix element to the change in the nucleon mass with respect to the strange quark mass. The final result of this calculation is m_s = 49 +-10 +- 15 MeV which can be translated into f_s = m_s / m_N = 0.053 +- 0.011 +- 0.016. Given the lack of a quantitative comparison of this phenomenologically important quantity determined from various lattice QCD calculations, we take the opportunity to present such an average. The resulting conservative determination is (all uncertainties added in quadrature) f_s = 0.043 +- 0.011 (99 % confidence interval).
Stability of strange dwarfs: a comparison with observations
International Nuclear Information System (INIS)
We study the stability of strange dwarfs, superdense stars with a small self-confining core (Mcore < 0.02M⊙) containing strange quark matter and an extended crust consisting of atomic nuclei and degenerate electron gas. The mass and the radius of these stars are of the same order of magnitude as those of ordinary white dwarfs. It is shown that any study of their stability must examine the dependence of the mass on two variables, which can, for convenience, be taken to be the rest mass (total baryon number) of the quark core and the energy density ρtr of the crust at the surface of the quark core. The range of variation of these quantities over which strange dwarfs are stable is determined. This region is referred to as the stability valley for strange dwarfs. The mass and radius obtained from theoretical models of strange dwarfs are compared with observational data obtained through the HIPPARCOS program and the most probable candidate strange dwarfs are identified.
Effects of Density-Dependent Quark Mass on Phase Diagram of Color-Flavor-Locked Quark Matter
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
Considering the density dependence of quark mass, we investigate the phase transition between the (unpaired) strange quark matter and the color-flavor-locked matter, which are supposed to be two candidates for the ground state of strongly interacting matter. We find that if the current mass of strange quark ms is small, the strange quark matter remains stable unless the baryon density is very high. If ms is large, the phase transition from the strange quark matter to the color-flavor-locked matter in particular to its gapless phase is found to be different from the results predicted by previous works. A complicated phase diagram of three-flavor quark matter is presented, in which the color-flavor-locked phase region is suppressed for moderate densities.
Strangeness production in deep inelastic muon nucleon scattering at 280 GeV
International Nuclear Information System (INIS)
The production of strange particles has been studied in a 280 GeV muon nucleon scattering experiment with acceptance and particle identification over a large kinematical range. The data show that at large values of xBj the interactions take place mostly on a u valence quark in agreement with the basic quark-parton model predictions. This feature results in a strong forward-backward asymmetry in the distribution of strangeness along the rapidity axis. The data are compatible with a strange to non-strange quark suppression factor of ≅0.3 and with a strong suppression of strange diquarks. The distributions of K+K- pairs show that the two kaons are preferentially produced at neighbouring values of rapidity. (orig.)
Stable $uuddbar s$ pentaquarks in the constituent quark model
Stancu, F; Stancu, Fl.
2003-01-01
The stability of strange pentaquarks $uuddbar s$ is studied in a constituent quark model based on a flavor-spin hyperfine interaction between quarks. With this interaction model, which schematically represents the Goldstone boson exchange interaction between constituent quarks, the lowest lying strange pentaquark is a $p-$shell state with positive parity. The flavor-spin interaction lowers the energy of the lowest $p-$shell state below that of the lowest $s-$shell state, which has negative parity because of the negative parity of the strange antiquark. It is found that the strange pentaquark is stable against strong decay provided that the strange antiquark interacts by a fairly strong spin-spin interaction with $u$ and $d$ quarks. This interaction has a form that corresponds to $eta$ meson exchange. Its strength may be inferred from the $pi^0$ decay width of $D_s^*$ mesons.
Simulations with dynamical HISQ quarks
Bazavov, A; DeTar, C; Freeman, W; Gottlieb, Steven; Heller, U M; Hetrick, J E; Laiho, J; Levkova, L; Oktay, M; Osborn, J; Sugar, R L; Toussaint, D; Van de Water, R S
2010-01-01
We report on the status of a program of generating and using configurations with four flavors of dynamical quarks, using the HISQ action. We study the lattice spacing dependence of physical quantities in these simulations, using runs at several lattice spacings, but with the light quark mass held fixed at two tenths of the strange quark mass. We find that the lattice artifacts in the HISQ simulations are much smaller than those in the asqtad simulations at the same lattice spacings and quark masses. We also discuss methods for setting the scale, or assigning a lattice spacing to ensembles run at unphysical parameters.
Evans, D; Bakke, H; Beusch, Werner; Bloodworth, Ian J; Caliandro, R; Carrer, N; Di Bari, D; Di Liberto, S; Elia, D; Fanebust, K; Fini, R A; Ftácnik, J; Ghidini, B; Grella, G; Helstrup, H; Holme, A K; Huss, D; Jacholkowski, A; Jones, G T; Kinson, J B; Knudson, K P; Králik, I; Lenti, V; Lietava, R; Loconsole, R A; Løvhøiden, G; Manzari, V; Mazzoni, M A; Meddi, F; Michalon, A; Michalon-Mentzer, M E; Morando, M; Norman, P I; Pastircák, B; Quercigh, Emanuele; Romano, G; Safarík, K; Sándor, L; Segato, G F; Staroba, P; Thompson, M; Thorsteinsen, T F; Torrieri, G D; Tveter, T S; Urbán, J; Villalobos Baillie, O; Virgili, T; Votruba, M F; Závada, P
2000-01-01
Strange and multi-strange baryon production is expected to be enhanced in heavy ion interactions if a phase transition from hadronic matter to a quark-gluon plasma takes place. The production yields and transverse mass spectra of strange and multi-strange baryons and anti-baryons are presented for lead-lead interactions at 158 GeV/c per nucleon. Yields and transverse mass spectra from proton-lead and proton-beryllium interactions, where no phase transition is expected, are also presented and compared to those from lead-lead interactions. (5 refs).
International Nuclear Information System (INIS)
Strange and multi-strange baryon production is expected to be enhanced in heavy ion interactions if a phase transition from hadronic matter to a Quark-Gluon Plasma takes place. The production yields and transverse mass spectra of strange and multi-strange baryons and anti-baryons are presented for lead-lead interactions at 158 GeV/c per nucleon. Yields and transverse mass spectra from proton-lead and proton-beryllium interactions, where no phase transition is expected, are also presented and compared to those from lead-lead interactions
Bare Higgs mass at Planck scale
Hamada, Yuta; Oda, Kin-ya
2013-01-01
In a certain quantum gravity/string theory context, it is possible that not only the physical Higgs mass but also the bare one (and hence the radiative corrections as well) can vanish at the Planck/string scale. We compute one and two loop quadratic divergent contributions to the bare Higgs mass in terms of the bare couplings in the Standard Model (SM). We approximate the bare couplings at the ultraviolet cutoff scale by the MSbar ones at the same scale, which we evaluate for the Higgs mass around 126GeV in the SM. We obtain the cutoff scale dependence of the bare Higgs mass up to two loop orders, and examine where it becomes zero. We find that if we take the current central value for the top quark pole mass, 173GeV, the bare Higgs mass vanishes at about 10^{23}GeV. With a 1.3 sigma smaller mass, 170GeV, the scale can be of the order of the Planck scale.
Xu, R X
2004-01-01
A quake model of bare strange stars for normal pulsar glitches is summarized. Three mechanisms being responsible for developing elastic stress energy are presented. It is suggested that other kinds of glitches (e.g, the frequency glitch in KS 1947+300 and in AXP/SGRs) could represent the bulk-strain-induced quakes. The apparent field increase of normal pulsars into ``magnetars'' could be the result of stellar catastrophic shrinking when the elastic force raises to a critical point.
Energy Technology Data Exchange (ETDEWEB)
Olinto, A.V. [Chicago Univ., IL (United States). Dept. of Astronomy and Astrophysics]|[Fermi National Accelerator Lab., Batavia, IL (United States)
1991-12-01
Strange matter may be the ground state of matter. We review the phenomenology and astrophysical implications of strange matter, and discuss the possible ways for testing the strange matter hypothesis.
Black Holes versus Strange Quark Matter
Gladysz-Dziadus, Ewa
2004-01-01
Interpretation of Centauro like events still remains the open question. To the list of models proposed to explain Centauros, the new idea based on mini black holes evaporation has been recently added by A. Mironov et al.. In our paper we give some comments to this scenario, showing that the hypothesis that Centauro like events result from decay of mini black holes, encounters various difficulties, when compared with experimental observations. The QGP strangelet mechanism, proposed in some of ...
Electroproduction of Baryon Resonances and Strangeness Suppression
Santopinto, E; Tecocoatzi, H Garcia
2016-01-01
We describe the electroproduction ratios of baryon-meson states from nucleon using an extension of the quark model that takes into account the sea. As a result we provide, with no adjustable parameters, the predictions of ratios of exclusive meson-baryon final states: Lambda K , Sigma K, p pion, and n pion. These predictions are in agreement with the new Jlab experimental data showing that sea quarks play an important role in the electroproduction. We also predicted further ratios of exclusive reactions that can be measured and tested in future experiments. In particular, we suggested new experiments on deuterium and tritium. Such measurements can provide crucial test of different predictions concerning the structure of nucleon and its sea quarks helping to solve an outstanding problem. Finally, we computed the so called strangeness suppression factor, lambda s, that is the suppression of strange quark-antiquarks compared to nonstrange pairs, and we found that our finding with this simple extension of the qua...
Strangeness in nuclear physics
Gal, A; Millener, D J
2016-01-01
Extensions of nuclear physics to the strange sector are reviewed, covering data and models of Lambda and other hypernuclei, multi-strange matter, and anti-kaon bound states and condensation. Past achievements are highlighted, present unresolved problems discussed, and future directions outlined.
Probing the strange nature of the nucleon with phi photoproduction
International Nuclear Information System (INIS)
The presence inside the nucleon of a significant component of strange-antistrange quark pairs has been invoked to explain a number of current puzzles in the low energy realm of QCD. The σ term in πN scattering is a venerable conundrum which can be explained with a 10%--20% admixture. The spin crisis brought on by the EMC result and follow on experiments was first interpreted as requiring a large strange content of s quarks whose spin helped cancel the contribution of the u and d quarks to the nucleon spin, again of order 10%. Excess phi meson production in p anti p annihilation at LEAR has also been explained in terms of up to a 19% admixture of s anti s pairs. Charm production in deep-inelastic neutrino scattering would appear to provide evidence for a 3% strange sea. It is clear that a definite probe of the strange quark content would be an invaluable tool in unraveling a number of mysteries. The longitudinal beam target asymmetry in ψ photoproduction is a particularly sensitive probe of that content. It is explored here
Strange and charm meson masses from twisted mass lattice QCD
International Nuclear Information System (INIS)
We present results of a twisted mass lattice QCD computation of the strange and charm meson spectrum with 2+1+1 dynamical quark flavors. Particular focus is put on excited D and Ds mesons and on a connection to the ''1/2,3/2 limit'' for the D(s)**.
Strange matter - a new domain of nuclear physics
International Nuclear Information System (INIS)
Relativistic heavy ion collisions offer the exciting possibility to produce exotic (meta-)stable states of nuclear matter containing (roughly) equal number of strangeness compared to the content in baryon number: Strangelets, i.e. small pieces of strange quark matter (SQM), were proposed as a signal of QGP formation. However, as their hadronic counterpart, also new multihypernuclear objects, i.e. small pieces of strange hadronic matter (SHM), may show up with rather very similar properties. This observation gives raise to the speculation that both states might have a strong overlap and correlation. In this overview we review the reasoning of both their stability and existence, the possible separation of strangeness necessary for their formation and the chances for their detection. (orig.)
ALICE, CERN; The ALICE collaboration
2016-01-01
The yields of strange and multi-strange hadrons are measured at midrapidity in proton-proton (pp) collisions at s = 7 TeV as a function of the charged-particle multiplicity density (dNch/dη). The production rate of strange particles increases faster than that of non-strange hadrons, leading to an enhancement of strange particles relative to pions, similar to that found in nucleus-nucleus collisions as well as in proton-nucleus collisions at the LHC. This is the first observation of an enhanced production of strange particles in high-multiplicity pp collisions. The magnitude of this strangeness enhancement increases with the event activity, quantified by dNch/dη, and with hadron strangeness. It reaches almost a factor of two for the Ω at the highest multiplicity presented. No enhancement is observed for particles with no strange quark content, demonstrating that the observed effect is strangeness rather than mass related. The results are not reproduced by any of the Monte Carlo models commonly used at the L...
Quark liberation and coalescence at CERN SPS
Zimányi, J; Csörgö, T; Lévai, Peter
2000-01-01
The linear coalescence approach to hadronization of quark matter is shown to have problems with strangeness conservation in a baryon rich environment. The simplest correct quark counting is shown to coincide with the non-linear algebraic coalescence rehadronization model, ALCOR. We argue that experimental facts agree with the assumption that quark degrees of freedom are liberated before hadron formation in 158 AGeV central Pb+Pb collisions at CERN SPS. (13 refs).
Baryon masses with improved staggered quarks
Bernard, C; DeTar, C; Gottlieb, S; Heller, U M; Hetrick, J E; Levkova, L; Osborn, J; Renner, D B; Sugar, R; Toussaint, D
2007-01-01
The MILC collaboration's simulations with improved staggered quarks are being extended with runs at a lattice spacing of 0.06 fm with quark masses down to one tenth the strange quark mass. We give a brief introduction to these new simulations and the determination of the lattice spacing. Then we combine these new runs with older results to study the masses of the nucleon and the Omega minus in the continuum and chiral limits.
Strangeness production in deep inelastic muon nucleon scattering at 280 GeV
Arneodo, M.; Arvidson, A.; Aubert, J. J.; Badelek, B.; Beaufays, J.; Bee, C. P.; Benchouk, C.; Berghoff, G.; Bird, I.; Blum, D.; Böhm, E.; de Bouard, X.; Brasse, F. W.; Braun, H.; Broll, C.; Brown, S.; Brück, H.; Calen, H.; Chima, J. S.; Ciborowski, J.; Clifft, R.; Coignet, G.; Combley, F.; Coughlan, J.; D'Agostini, G.; Dahlgren, S.; Dengler, F.; Derado, I.; Dreyer, T.; Drees, J.; Düren, M.; Eckhardt, V.; Edwards, A.; Edwards, M.; Ernst, T.; Eszes, G.; Favier, J.; Ferrero, M. I.; Figiel, J.; Flauger, W.; Foster, J.; Gabathuler, E.; Gajewski, J.; Gamet, R.; Gayler, J.; Geddes, N.; Grafström, P.; Grard, F.; Haas, J.; Hagberg, E.; Hasert, F. J.; Hayman, P.; Heusse, P.; Jaffré, M.; Jacholkowska, A.; Janata, F.; Jancso, G.; Johnson, A. S.; Kabuss, E. M.; Kellner, G.; Korbel, V.; Krüger, J.; Kullander, S.; Landgraf, U.; Lanske, D.; Loken, J.; Long, K.; Maire, M.; Malecki, P.; Manz, A.; Maselli, S.; Mohr, W.; Montanet, F.; Montgomery, H. E.; Nagy, E.; Nassalski, J.; Norton, P. R.; Oakham, F. G.; Osborne, A. M.; Pascaud, C.; Pawlik, B.; Payre, P.; Peroni, C.; Peschel, H.; Pessard, H.; Pettingale, J.; Pietrzyk, B.; Pönsgen, B.; Pötsch, M.; Renton, P.; Ribarics, P.; Rith, K.; Rondio, E.; Sandacz, A.; Scheer, M.; Schlagböhmer, A.; Schiemann, H.; Schmifz, N.; Schneegans, M.; Scholz, M.; Schröder, T.; Schouten, M.; Schultze, K.; Sloan, T.; Stier, H. E.; Studt, M.; Taylor, G. N.; Thénard, J. M.; Thompson, J. C.; de La Torre, A.; Toth, J.; Urban, L.; Wallucks, W.; Whalley, M.; Wheeler, S.; Williams, W. S. C.; Wimpenny, S. J.; Windmolders, R.
1987-09-01
The production of strange particles has been studied in a 280 GeV muon nucleon scattering experiment with acceptance and particle identification over a large kinematical range. The data show that at large values of x Bj the interactions take place mostly on a u valence quark in agreement with the basic quarkparton model predictions. This feature results in a strong forward-backward asymmetry in the distribution of strangeness along the rapidity axis. The data are compatible with a strange to non-strange quark suppression factor of ≈0.3 and with a strong suppression of strange diquarks. The distributions of K + K - pairs show that the two kaons are preferentially produced at neighbouring values of rapidity.
Strange and charm baryon masses with two flavors of dynamical twisted mass fermions
International Nuclear Information System (INIS)
The masses of the low-lying strange and charm baryons are evaluated using two degenerate flavors of twisted mass sea quarks for pion masses in the range of about 260 MeV to 450 MeV. The strange and charm valence quark masses are tuned to reproduce the mass of the kaon and D-meson at the physical point. The tree-level Symanzik improved gauge action is employed. We use three values of the lattice spacing, corresponding to β=3.9, β=4.05 and β=4.2 with r0/a=5.22(2), r0/a=6.61(3) and r0/a=8.31(5) respectively. We examine the dependence of the strange and charm baryons on the lattice spacing and strange and charm quark masses. The pion mass dependence is studied and physical results are obtained using heavy baryon chiral perturbation theory to extrapolate to the physical point.
Equations of state of quark star in color-flavour-locking phase
International Nuclear Information System (INIS)
The main objective of present work is to investigate the effects of CFL color superconducting gaps in quarks and Goldstone bosons in the EOS of high density quark matter and mass-radius (M-R) relationship of strange quark stars and quark stars with CFL phase
Gapless Color-Flavor-Locked Quark Matter
DEFF Research Database (Denmark)
Alford, Mark; Kouvaris, Christoforos; Rajagopal, Krishna
2004-01-01
In neutral cold quark matter that is sufficiently dense that the strange quark mass M_s is unimportant, all nine quarks (three colors; three flavors) pair in a color-flavor locked (CFL) pattern, and all fermionic quasiparticles have a gap. We argue that as a function of decreasing quark chemical...... a linear combination Qtilde of electric and color charges, but it is a Qtilde-conductor with a nonzero electron density. These electrons and the gapless quark quasiparticles make the low energy effective theory of the gapless CFL phase and, consequently, its astrophysical properties are qualitatively...
Quark-Antiquark Condensates in the Hadronic Phase
Tawfik, A
2005-01-01
We use a hadron resonance gas model to calculate the quark-antiquark condensates for light (up and down) and strange quark flavors at finite temperatures and chemical potentials. At zero chemical potentials, we find that at the temperature where the light quark-antiquark condensates entirely vanish the strange quark-antiquark condensate still keeps a relatively large fraction of its value in the vacuum. This is in agreement with results obtained in lattice simulations and in chiral perturbation theory at finite temperature and zero chemical potentials. Furthermore, we find that this effect slowly disappears at larger baryon chemical potential. These results might have significant consequences for our understanding of QCD at finite temperatures and chemical potentials. Concretely, our results imply that there might be a domain of temperatures where chiral symmetry is restored for light quarks, but still broken for strange quark that persists at small chemical potentials. This might have practical consequences ...
Strange decays of nonstrange baryons
International Nuclear Information System (INIS)
The strong decays of excited nonstrange baryons into the final states ΛK, ΣK, and for the first time into Λ(1405)K, Λ(1520)K, Σ(1385)K, ΛK*, and ΣK*, are examined in a relativized quark pair creation model. The wave functions and parameters of the model are fixed by previous calculations of Nπ and Nππ, etc., decays. The results show that it should be possible to discover several new negative parity excited baryons and confirm the discovery of several others by analyzing these final states in kaon production experiments. They also establish clear predictions for the relative strengths of certain states to decay to Λ(1405)K and Λ(1520)K, which can be tested to determine if a three-quark model of the Λ(1405)K is valid. The authors results compare favorably with the results of partial wave analyses of the limited existing data for the ΛK and ΣK channels. They do not find large ΣK decay amplitudes for a substantial group of predicted and weakly established negative-parity states, in contrast to the only previous work to consider decays of these states into the strange final states ΛK and ΣK
Strangeness Production in AA and pp Collisions
Satz, P Castorina ad H
2016-01-01
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 ($pp$, $e^+e^-$) 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 det...
Anomalies, symmetries and strangeness content of the proton
Indian Academy of Sciences (India)
J Pasupathy
2003-11-01
The matrix elements of the operators of strange quark ﬁelds $s\\overline{}s$ 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, while the determination of the axial vector current matrix element is from QCD sum rules. These correspond to $\\langle p|2\\overline{ss}|\\rangle / \\langle p|\\overline{u}u+\\overline{d}d|p\\rangle ≈ 0.12$ and for the axial current ≈ -0.12, respectively. The role of the anomalies in maintaining ﬂavor symmetry in the presence of substantial differences in quark masses is pointed out. This suggests that there is no need to invoke an intrinsic strange quark component in the proton wave function.
Recurrences of strange attractors
Indian Academy of Sciences (India)
E J Ngamga; A Nandi; R Ramaswamy; M C Romano; M Thiel; J Kurths
2008-06-01
The transitions from or to strange nonchaotic attractors are investigated by recurrence plot-based methods. The techniques used here take into account the recurrence times and the fact that trajectories on strange nonchaotic attractors (SNAs) synchronize. The performance of these techniques is shown for the Heagy-Hammel transition to SNAs and for the fractalization transition to SNAs for which other usual nonlinear analysis tools are not successful.
Chemical equilibration of strangeness
Sollfrank, Josef
1997-01-01
Thermal models are very useful in the understanding of particle production in general and especially in the case of strangeness. We summarize the assumptions which go into a thermal model calculation and which differ in the application of various groups. We compare the different results to each other. Using our own calculation we discuss the validity of the thermal model and the amount of strangeness equilibration at CERN-SPS energies. Finally the implications of the thermal analysis on the r...
[Through strangeness to oneself].
Sorgedrager, D B
1993-11-01
"Being strange" as opposed to "being oneself" is part of the thinking in all cultures. Belonging to a given culture is actually defined by ones identity and by "being oneself". Both concepts--"being oneself" or "being strange"--are rational and related constructs. Whatever they are confronted with, for most human beings it is self-evident to differentiate between subject and object, between "being oneself" or "being strange". This explains why thinking often occurs in opposites or polarities, as an either/or. All "being strange" has its origins in one's own self. "Being strange" becomes most obvious when persons, gestalt or cultures strongly deviate from one's own familiar situation. It is part of man's disposition to be cautious, suspicious of and at distance from everything considered strange and different. That explains his xenophobia feelings and actions. Behind this attitude we can always discover one's wish to preserve the familiar beliefs--combined with an uneasiness to give up one's thinking and behaviour that is proven and routine. It is only by reflecting on our own culture and our own inheritance that we have the possibility to come to terms with our own ethnic identity and foreign behavioral patterns. If we do not try to understand other cultures while keeping our own cultural identity, tensions and violent conflicts will inevitably result. PMID:8278564
Massive quark polarization in Quantum Chromodynamics subprocesses
International Nuclear Information System (INIS)
It is well known that the single polarization asymmetries are large in hyperon production in contrast with naive Quantum Chromodynamics predictions. We have explored the possibility of polarization of quarks in QCD subprocesses, assuming that the quark mass can be significant at energies of interest. The fourth order contribution to the single spin asymmetry in each important subprocess for strange quark production is calculated. Mass dependence and the kinematical properties of the polarization of the strange quark in the partons' center-of-mass frame are discussed. The s-quark polarization in the hadrons' center-of-mass frame is obtained by performing the convolution integrations with the initial state parton distribution functions. A fit to the hyperon polarization is presented that reproduces the unique and striking kinematic dependence of the data. This is evidence that the ''seed'' of the polarization is in the basic scattering process and it is dominated by the gluon fusion subprocess. 31 figs
Flavor content of the nucleon in an unquenched quark model
Bijker, R
2008-01-01
We discuss the flavor content of the nucleon in an unquenched quark model in which the effects of quark-antiquark pairs (up, down and strange) are taken into account in an explicit form. It is shown that the inclusion of quark-antiquark pairs leads to an excess of anti-d over anti-u quarks in the proton and to a large contribution of orbital angular momentum to the spin of the proton.
Unquenched domain wall quarks with multi-bosons
Montvay, I.
2002-01-01
The numerical simulation of domain wall quarks with the two-step multi-boson (TSMB) algorithm is considered. The inclusion of single quark flavours, as required for strange quarks, is discussed. The usage of computer memory can be kept relatively low, independently of the order of polynomial approximations. Tests are performed with two flavours (N_f=2) of degenerate quarks near the N_t=4 thermodynamical cross over.
Strange Vector Form Factors from Parity-Violating Electron Scattering
International Nuclear Information System (INIS)
The simplest models might describe the nucleon as 3 light quarks, but this description would be incomplete without inclusion of the sea of glue and q q-bar pairs which binds it. Early indications of a particularly large contribution from strange quarks in this sea to the spin and mass of the nucleon motivated an experimental program examining the role of these strange quarks in the nucleon vector form factors. The strangeness form factors can be extracted from the well-studied electromagnetic structure of the nucleon using parity-violation in electron-nuclear scattering to isolate the effect of the weak interaction. With high luminosity and polarization, and a very stable beam due to its superconducting RF cavities, CEBAF at Jefferson Lab is a precision instrument uniquely well suited to the challenge of measurements of the small parity-violating asymmetries. The techniques and results of the two major Jefferson Lab experimental efforts in parity-violation studies, HAPPEX and G0, as well as efforts to describe the strange form factors in QCD, will be reviewed.
Strange vector form factors from parity-violating electron scattering
Energy Technology Data Exchange (ETDEWEB)
Kent Paschke, Anthony Thomas, Robert Michaels, David Armstrong
2011-06-01
The simplest models might describe the nucleon as 3 light quarks, but this description would be incomplete without inclusion of the sea of glue and qbar q pairs which binds it. Early indications of a particularly large contribution from strange quarks in this sea to the spin and mass of the nucleon motivated an experimental program examining the role of these strange quarks in the nucleon vector form factors. The strangeness form factors can be extracted from the well-studied electromagnetic structure of the nucleon using parity-violation in electron-nuclear scattering to isolate the effect of the weak interaction. With high luminosity and polarization, and a very stable beam due to its superconducting RF cavities, CEBAF at Jefferson Lab is a precision instrument uniquely well suited to the challenge of measurements of the small parity-violating asymmetries. The techniques and results of the two major Jefferson Lab experimental efforts in parity-violation studies, HAPPEX and G0, as well as efforts to describe the strange form factors in QCD, will be reviewed.
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; Vargas Trevino, Aurora Diozcora; 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
2016-01-01
The yields of strange (${\\rm K}^{0}_{S}$, $\\Lambda$, $\\bar{\\Lambda}$) and multi-strange ($\\Xi^{-}$, $\\bar{\\Xi}^{+}$, $\\Omega^{-}$, $\\bar{\\Omega}^{+}$) hadrons are measured at midrapidity in proton-proton (pp) collisions at $\\sqrt{s}$ = 7 TeV as a function of the charged-particle multiplicity density (${\\rm d}N_{\\rm ch}/{\\rm d}\\eta$).The production rate of strange particles increases faster than that of non-strange hadrons, leading to an enhancement of strange particles relative to pions, similar to that found in nucleus-nucleus collisions as well as in proton-nucleus collisions at the LHC. This is the first observation of an enhanced production of strange particles in high-multiplicity pp collisions. The magnitude of this strangeness enhancement increases with the event activity, quantified by ${\\rm d}N_{\\rm ch}/{\\rm d}\\eta$, and with hadron strangeness. It reaches almost a factor of two for the $\\Omega$ at the highest multiplicity presented. No enhancement is observed for particles with no strange quark cont...
Scalar strangeness content of the nucleon and baryon sigma terms
Ren, Xiu-Lei; Geng, Li-Sheng; Meng, Jie
2014-01-01
The scalar strangeness content of the nucleon, characterized by the so-called strangeness-nucleon sigma term, is of fundamental importance in understanding its sea-quark flavor structure. We report a determination of the octet baryon sigma terms via the Feynman-Hellmann theorem by analyzing the latest high-statistics $n_f=2+1$ lattice QCD simulations with covariant baryon chiral perturbation theory up to next-to-next-to-next-to-leading order. In particular, we predict $\\sigma_{\\pi N}=55(1)(4)...
The equation of state in nucleon and strange stars
International Nuclear Information System (INIS)
The equation of state (EOS) is an essential physical ingredient in simulations of gravitational collapse, supernovae, old and newly born neutron stars, and binary mergers of compact stars. In this talk, I will examine (1) the extent to which stringent constraints may be placed on the EOS by a comparison of calculations with the available data on some basic neutron star properties; and (2) some astrophysical consequences of the possible presence of strangeness, in the form of baryons, notably the Λ and Σ-, or as a Bose condensate, such as a K- meson condensate, or in the form of strange quarks. copyright 1997 American Institute of Physics
Recent top quark results from ATLAS
Mcgoldrick, Garrin; The ATLAS collaboration
2016-01-01
The top quark is the heaviest known fundamental particle. As it is the only quark that decays before it hadronizes, this gives us the unique opportunity to probe the properties of bare quarks. This talk will focus on a few recent precision top quark measurements by the ATLAS Collaboration: fiducial top pair and single top production cross sections including differential distributions will be presented alongside selected measurements of top quark properties. The results include the first top quark measurements at 13 TeV using data from the 2015 LHC run.
Strange and non-strange sea quark–gluon effects in nucleons
Energy Technology Data Exchange (ETDEWEB)
Batra, M.; Upadhyay, A.
2014-02-15
Within a statistical approach, strange and non-strange quark–gluon Fock state contributions are analyzed for their low energy properties. A suitable wave function is written for a nucleon that consists of three valence quarks (qqq) and the sea (g,qq{sup ¯}). Expansion of the nucleonic system in terms of Fock states that contain (g,qq{sup ¯}) is assumed and the probabilities of all possible Fock states, that lead to such a wave-function containing strange and non-strange quark–gluon contents in the sea are determined. Various approximations are entertained to validate the authenticity of the model used. The statistically determined coefficients strongly favor a vector-dominated sea where the sea includes ss{sup ¯} pairs. Additionally, the sea is constrained to have a limited number of components. The phenomenological implications that affect the low energy properties are discussed. The obtained results are compared to existing theoretical models and experimental data. -- Highlights: • A general expression to determine probabilities for each quark–gluon Fock states. • To calculate probabilities in flavor, spin and color space in statistical framework. • To analyze the sea-content and examine the contribution to various properties.
Scalar resonances as two-quark states
International Nuclear Information System (INIS)
On the base of the theory with U(3)xU(3) symmetric chiral Lagrangian the properties of the two-quark scalar mesons are considered. It is shown, that the scalar resonances delta (980) and K(1240) may be treated as the p-wave states of anti qq system. The properties of the isovector and strange scalar mesons, obtained as a propetrties of the two-quark states, turn out to be very close to the properties of the isovector scalar resonance delta (980) and strange resonance K(1240)
Fortunati, Lucien
2015-01-01
If you’re at CERN at the moment, you will certainly have noticed the work under way on the Globe. The structure, which has been in pride of place opposite the Laboratory for over ten years, has never been so completely laid bare. But, as we explained in a previous article (see here), it is all for a good cause. The Globe is built entirely from wood and certain parts of it need to be replaced.
Electroproduction of baryon-meson states and strangeness suppression
Santopinto, E.; García-Tecocoatzi, H.; Bijker, R.
2016-08-01
We describe the electroproduction ratios of baryon-meson states from nucleon, inferring from the sea quarks in the nucleon using an extension of the quark model that takes into account the sea. As a result we provide, with no adjustable parameters, the predictions of ratios of exclusive meson-baryon final states: ΛK+, Σ* K, ΣK, pπ0, and nπ+. These predictions are in agreement with the new JLab experimental data showing that sea quarks play an important role in the electroproduction. We also predicted further ratios of exclusive reactions that can be measured and tested in future experiments. In particular, we suggested new experiments on deuterium and tritium. Such measurements can provide crucial tests of different predictions concerning the structure of nucleon and its sea quarks helping to solve an outstanding problem. Finally, we compute the so called strangeness suppression factor, λs, that is the suppression of strange quark-antiquark pairs compared to nonstrange pairs, and we found that our finding with this simple extension of the quark model is in good agreement with the results of JLab and CERN experiments.
Strangeness production in AA and pp collisions
Castorina, Paolo; Satz, Helmut
2016-07-01
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^+e^- 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.
Pseudoscalar meson physics with four dynamical quarks
Bazavov, A; Bouchard, C; DeTar, C; Du, D; El-Khadra, A X; Foley, J; Freeland, E D; Gamiz, E; Gottlieb, Steven; Heller, U M; Hetrick, J E; Kim, J; Kronfeld, A S; Laiho, J; Levkova, L; Lightman, M; Mackenzie, P B; Neil, E T; Oktay, M; Simone, J N; Sugar, R L; Toussaint, D; Van de Water, R S; Zhou, R
2012-01-01
We present preliminary results for light, strange and charmed pseudoscalar meson physics from simulations using four flavors of dynamical quarks with the highly improved staggered quark (HISQ) action. These simulations include lattice spacings ranging from 0.15 to 0.06 fm, and sea-quark masses both above and at their physical value. The major results are charm meson decay constants f_D, f_{D_s} and f_{D_s}/f_D and ratios of quark masses. This talk will focus on our procedures for finding the decay constants on each ensemble, the continuum extrapolation, and estimates of systematic error.
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
String Junction Model, Cluster Hypothesis, Penta-Quark Baryon and Tetra-Quark Meson
Imachi, Masahiro; Otsuki, Shoichiro
2007-01-01
Thirty years ago we proposed string junction model of hadrons and examined structure and reaction of hadrons including exotic ones. Since 2003 some attentions have been paid to exotic hadrons, especially to penta-quark baryon. By critically examining its theoretical analysis of Diakonov et. al, we introduce to our model "cluster hypothesis", which guarantees the classical and established picture that mass difference of hadrons among flavor multiplet members comes from that of the constituents. According to the hypothesis, the penta-quark baryon Theta^+ (S=+1) including a strange anti-quark s(bar), which is assigned to a member of 10^* representation of flavor SU(3), is heavier than non-strange members of the multiplet by Delta_s =130 ~ 150 MeV, the mass difference between the strange and non-strange quarks. In our model the mass of the penta-quark baryon is estimated as around 3 GeV. Quite recently, the Belle Collaboration has reported a candidate for tetra-quark meson, Z^+(4430 MeV). This gives us powerful c...
Hawking-Unruh hadronization and strangeness production in high energy collisions
Directory of Open Access Journals (Sweden)
Castorina Paolo
2015-01-01
Full Text Available The interpretation of quark (q- antiquark (q̄ pairs production and the sequential string breaking as tunneling through the event horizon of colour confinement leads to a thermal hadronic spectrum with a universal Unruh temperature, T ≃ 165 Mev, related to the quark acceleration, a, by T = a/2π. The resulting temperature depends on the quark mass and then on the content of the produced hadrons, causing a deviation from full equilibrium and hence a suppression of strange particle production in elementary collisions. In nucleus-nucleus collisions, where the quark density is much bigger, one has to introduce an average temperature (acceleration which dilutes the quark mass effect and the strangeness suppression almost disappears.
Octet baryon mass splittings from up-down quark mass differences
Horsley, R; Nakamura, Y; Pleiter, D; Rakow, P E L; Schierholz, G; Zanotti, J M
2012-01-01
Using an SU(3) flavour symmetry breaking expansion in the quark mass, we determine the QCD component of the neutron-proton, Sigma and Xi mass splittings of the baryon octet due to up-down (and strange) quark mass differences. Provided the average quark mass is kept constant, the expansion coefficients in our procedure can be determined from computationally cheaper simulations with mass degenerate sea quarks and partially quenched valence quarks. Full details and numerical results are given in ref 1.
Constraints on the critical temperature of the phase transition to the quark-gluon plasma
International Nuclear Information System (INIS)
Low temperatures of the phase transition to the quark-gluon plasma correspond to low values of the bag model constants and to absolutely stable strange quark matter. Some of the observed pulsars are identified quite reliably as neutron stars. If strange matter is stable, the central density of these pulsars has to be smaller that critical density of the phase transition to nonstrange quark matter. The nonstrange quark matter being formed turns to more stable strange matter on a weak interaction timescale, converting neutron stars into strange stars. The requirement of stability of old and newly born neutron stars is used to constrain the bag model constant and the critical temperature of the phase transition to the quark-gluon plasma at zero chemical potential. 16 refs., 1 tab
Constraints for critical temperature of the phase transition into the quark-gluon plasma
International Nuclear Information System (INIS)
Low temperature of the phase transition into the quark-gluon plasma correspond to low values of the bag model constant and to absolutely stable strange quark matter. Some of the observed pulsars are identified quite reliably as neutron stars. If strange matter is stable, the central density of these pulsars is to be smaller that critical density of the phase transition into the nonstrange quark matter. The nonstrange quark matter being formed turns to more stable strange matter on a weak interaction timescale converting neutron stars into strange stars. The requirement of stability of old and newly born neutron stars is used to constrain the bag model constant and the critical temperature of the phase transition into the quark-gluon plasma at zero chemical potential. (orig.)
Relativistic quark model for the Omega- electromagnetic form factors
Energy Technology Data Exchange (ETDEWEB)
G. Ramalho, K. Tsushima, Franz Gross
2009-08-01
We compute the Omega- electromagnetic form factors and the decuplet baryon magnetic moments using a quark model application of the Covariant Spectator Theory. Our predictions for the Omega- electromagnetic form factors can be tested in the future by lattice QCD simulations at the physical strange quark mass.
Current and constituent quark masses
International Nuclear Information System (INIS)
It is shown how the current quark mass, engendered by the electroweak sector, gives rise to a constituent quark mass, via the Dyson-Schwinger equations. The chiral symmetry breaking phenomenon on massless QCD is thereby seen to have an implementable generalization to the situation in which the strong bare mass is non-zero. A consistent renormalization is carried out for an arbitrary covariant gauge. (author). 16 refs
Strange particle production in neutrino-neon charged current interactions
International Nuclear Information System (INIS)
Neutral strange particle production in charged-current muon-neutrino interactions have been studied in the Fermilab 15-foot neon bubble chamber. Associated production is expected to be the major source of strange particles in charged-current neutrino interactions. σ-neutral and ξ-minus production by neutrinos was observed. The dependence on various leptonic and hadronic variables is investigated. A fit to single and associated production of s, s/anti-s, and c quarks is described based on the number of single and double strange particle production events. Inclusive neutral strange particle decays (V0) production rates as a fraction of all charged-current events are measured and are tabulated. The λ/K ratio is found to be 0.39 +- 0.04 and the fraction of λ coming from σ-neutral is (16 +- 5)%. The single- and double V0 production was used to determine the associated s anti-s production rate and single s-quark production rate. 13 refs., 7 figs., 3 tabs
Low lying baryon spectrum with N{sub f}=2+1+1 dynamical twisted quarks
Energy Technology Data Exchange (ETDEWEB)
Drach, Vincent; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Carbonell, Jaume; Papinutto, Mauro [UJF, CNRS/IN2P3, INPG (France). Lab. de Physique Subatomique et de Cosmologie; Alexandrou, Constantia [Cyprus Univ., Nicosia (Cyprus). Dept. of Physics
2010-12-15
We present first results on the octet and decuplet strange baryon spectrum with N{sub f}=2+1+1 twisted mass quarks. We use an Osterwalder Seiler valence strange quark with a mass tuned to the kaon and compare the results with those obtained in the unitary setup. This comparison allows to perform a first study of the lattice artefacts introduced by the mixed action approach. We investigate the effect of the strange and charm quarks in the sea by using two lattice spacings and comparing with preceding N{sub f}=2 twisted mass fermion calculations. (orig.)
Low lying baryon spectrum with Nf=2+1+1 dynamical twisted quarks
International Nuclear Information System (INIS)
We present first results on the octet and decuplet strange baryon spectrum with Nf=2+1+1 twisted mass quarks. We use an Osterwalder Seiler valence strange quark with a mass tuned to the kaon and compare the results with those obtained in the unitary setup. This comparison allows to perform a first study of the lattice artefacts introduced by the mixed action approach. We investigate the effect of the strange and charm quarks in the sea by using two lattice spacings and comparing with preceding Nf=2 twisted mass fermion calculations. (orig.)
Generalized isothermal models with strange equation of state
Indian Academy of Sciences (India)
S D Maharaj; S Thirukkanesh
2009-03-01
We consider the linear equation of state for matter distributions that may be applied to strange stars with quark matter. In our general approach the compact relativistic body allows for anisotropic pressures in the presence of the electromagnetic field. New exact solutions are found to the Einstein–Maxwell system. A particular case is shown to be regular at the stellar centre. In the isotropic limit we regain the general relativistic isothermal Universe. We show that the mass corresponds to the values obtained previously for quark stars when anisotropy and charge are present.
Strangeness suppression of qq creation observed in exclusive reactions.
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. PMID:25375706
Heating (Gapless) Color-Flavor Locked Quark Matter
DEFF Research Database (Denmark)
Fukushima, Kenji; Kouvaris, Christoforos; Rajagopal, Krishna
2005-01-01
We explore the phase diagram of neutral quark matter at high baryon density as a function of the temperature T and the strange quark mass Ms. At T=0, there is a sharp distinction between the insulating color-flavor locked (CFL) phase, which occurs where Ms^2/mu 0 and Delta_2->0) cross. Because we...... do not make any small-Ms approximation, if we choose a relatively strong coupling leading to large gap parameters, we are able to pursue the analysis of the phase diagram all the way up to such large values of Ms that there are no strange quarks present....
Strange hadron production at SIS energies: an update from HADES
Czech Academy of Sciences Publication Activity Database
Lorenz, M.; Adamczewski-Musch, J.; Arnold, O.; Krása, Antonín; Kugler, Andrej; Sobolev, Yuri, G.; Svoboda, Ondřej; Tlustý, Pavel; Wagner, Vladimír
Vol. 668. Bristol: IOP Publishing Ltd., 2016, s. 012022. ISSN 1742-6588. [15th International Conference on Strangeness in Quark Matter (SQM). Dubna (RU), 06.07.2015-11.07.2015] R&D Projects: GA MŠk LG12007; GA ČR GA13-06759S Institutional support: RVO:61389005 Keywords : heavy ion collisions * nuclear equation * kaon production Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders
Strangeness in the nucleon: what have we learned?
Thomas, A. W.; Shanahan, P. E.; Young, R.D.(ARC Centre of Excellence for Particle Physics at the Terascale and CSSM, School of Chemistry and Physics, University of Adelaide, Adelaide, SA 5005, Australia)
2012-01-01
We review the state of our knowledge concerning the contribution of strange quarks to various nucleon properties. In the case of the electric and magnetic form factors, the level of agreement between theory and experiment is very satisfactory and gives us considerable confidence in our capacity to make reliable calculations within non-perturbative QCD. In view of the importance of the scalar form factors to the detection of dark matter candidates such as neutralinos, we place a particular emp...
Strange Vector Form Factors from Parity-Violating Electron Scattering
Paschke, Kent; Michaels, Robert; Armstrong, David; 10.1088/1742-6596/299/1/012003
2011-01-01
The simplest models might describe the nucleon as 3 light quarks, but this description would be incomplete without inclusion of the sea of glue and q-qbar pairs which binds it. Early indications of a particularly large contribution from strange quarks in this sea to the spin and mass of the nucleon motivated an experimental program examining the role of these strange quarks in the nucleon vector form factors. The strangeness form factors can be extracted from the well-studied electromagnetic structure of the nucleon using parity-violation in electron-nuclear scattering to isolate the effect of the weak interaction. With high luminosity and polarization, and a very stable beam due to its superconducting RF cavities, CEBAF at Jefferson Lab is a precision instrument uniquely well suited to the challenge of measurements of the small parity-violating asymmetries. The techniques and results of the two major Jefferson Lab experimental efforts in parity-violation studies, HAPPEX and G0, as well as efforts to describe...
Strange goings-on in the proton: a case for Cheshire cat
International Nuclear Information System (INIS)
Three strange hadronic phenomena at low energy - the nucleon size problem, the strange quark content of the nucleon and the proton spin problem - are discussed in the context of manifestation of the Cheshire Cat Principle in hadronic systems. A simple resolution of these problems is provided by a chiral bag description combined with the topological notion of the baryon based on the skyrmion model. Absence of smoking-gun signals for quark-gluon presence in the nonperturbative sector of QCD is claimed to be a natural consequence of the Cheshire Cat Principle
Report of the Quark Flavor Physics Working Group
Butler, J N; Ritchie, J L; Cirigliano, V; Kettell, S; Briere, R; Petrov, A A; Schwartz, A; Skwarnicki, T; Zupan, J; Christ, N; Sharpe, S R; Van de Water, R S; Altmannshofer, W; Arkani-Hamed, N; Artuso, M; Asner, D M; Bernard, C; Bevan, A J; Blanke, M; Bonvicini, G; Browder, T E; Bryman, D A; Campana, P; Cenci, R; Cline, D; Comfort, J; Cronin-Hennessy, D; Datta, A; Dobbs, S; Duraisamy, M; El-Khadra, A X; Fast, J E; Forty, R; Flood, K T; Gershon, T; Grossman, Y; Hamilton, B; Hill, C T; Hill, R J; Hitlin, D G; Jaffe, D E; Jawahery, A; Jessop, C P; Kagan, A L; Kaplan, D M; Kohl, M; Krizan, P; Kronfeld, A S; Lee, K; Littenberg, L S; MacFarlane, D B; Mackenzie, P B; Meadows, B T; Olsen, J; Papucci, M; Parsa, Z; Paz, G; Perez, G; Piilonen, L E; Pitts, K; Purohit, M V; Quinn, B; Ratcliff, B N; Roberts, D A; Rosner, J L; Rubin, P; Seeman, J; Seth, K K; Schmidt, B; Schopper, A; Sokoloff, M D; Soni, A; Stenson, K; Stone, S; Sundrum, R; Tschirhart, R; Vainshtein, A; Wah, Y W; Wilkinson, G; Wise, M B; Worcester, E; Xu, J; Yamanaka, T
2013-01-01
This report represents the response of the Intensity Frontier Quark Flavor Physics Working Group to the Snowmass charge. We summarize the current status of quark flavor physics and identify many exciting future opportunities for studying the properties of strange, charm, and bottom quarks. The ability of these studies to reveal the effects of new physics at high mass scales make them an essential ingredient in a well-balanced experimental particle physics program.
Quark matter in massive neutron stars
International Nuclear Information System (INIS)
The recent observation of the pulsar PSR J1614-2230 with a mass of 1.97 solar masses gives a strong constraint on the nuclear matter equation of state. We explore the parameter ranges for a parameterized equation of state for quark stars. We find that such massive objects made of absolutely stable strange quark matter can reach the new constraint only if effects from the strong coupling constant and color superconductivity are considered. Also hybrid stars are able to be massive but a pure quark matter core appears only if the hadronic equation of state is stiff. A soft hadronic equation of state would imply that hybrid stars contain just a core of quark hadron mixed phase. In general, due to the softening of the equation of state at the quark-hadron phase transition the masses of hybrid stars stay below the ones of hadronic and pure quark stars.
Incompressibility of strange matter
Sinha, M N; Dey, J; Dey, M; Ray, S; Bhowmick, S; Sinha, Monika; Bagchi, Manjari; Dey, Jishnu; Dey, Mira; Ray, Subharthi; Bhowmick, Siddhartha
2002-01-01
Strange stars calculated from a realistic equation of state (EOS) show compact objects in the mass radius curve, when they are solved for gravitational fields via TOV equation. Many of the observed stars seem to fit in with this kind of compactness irrespective of whether they are X-ray pulsars, bursters or soft $\\gamma$ repeaters or radio pulsars. Calculated incompressibility of this strange matter shows continuity with that of nuclear matter. This is important in the cosmic separation of phase scenario. We compare our calculations of incompressibility with that of a nuclear matter EOS. This EOS has a continuous transition to ud-matter at about five times normal density. From a look at the consequent velocity of sound it is found that the transition to ud-matter seems necessary.
Strangeness in Nuclear Physics
Czech Academy of Sciences Publication Activity Database
Bydžovský, Petr
Košice: Slovak Physical Society, 2012 - (Reiffers, M.), s. 7-12 ISBN 978-80-970625-4-5. [17th Conference of Czech and Slovak Physicists. Žilina (SK), 05.09.2011-08.09.2011] R&D Projects: GA ČR GA202/08/0984 Institutional research plan: CEZ:AV0Z10480505 Keywords : strangeness production * hypernuclei * hyper electroproduction Subject RIV: BE - Theoretical Physics
Anaïs Schaeffer
2015-01-01
If you’re at CERN at the moment, you will certainly have noticed the work under way on the Globe. The structure, which has been in pride of place opposite the Laboratory for over ten years, has never been so completely laid bare. But, as we explained in a previous article (see here), it is all for a good cause. The Globe is built entirely from wood and certain parts of it need to be replaced. The Globe after the removal of all the sun baffles. Image: Lucien Fortunati. Picture the general structure of the Globe. In simple terms, the building consists of two spheres, one inside the other. The inner sphere houses the Universe of Particles exhibition and the conference room and is connected to the outer sphere by two access ramps. “Each of these two spheres is made up of eighteen large supporting arcs,” explains Amaya Martínez García of the GS department, who is supervising the Globe renovation project. “These eighteen arcs are ...
Energy Technology Data Exchange (ETDEWEB)
Pages, P.
1996-05-07
The thesis work is relative to an analysis of data collected by the DELPHI detector at LET in 1992 and 1993, in order to study the inclusive production production of {phi}{sup 0} mesons, reconstructed according to the decay mode {phi}{sup 0} {yields} K{sup +}K{sup -}. The kaon identification, indispensable to do this reconstruction, was made by the Barrel RICH detector of DELPHI. This study was first done to test the {phi}{sup 0} production in the Lund string model, which is one of the models used to describe the production of hadrons in the e{sup +}e{sup -}processes. The experimental distribution of the differential cross section of the inclusive {phi}{sup 0} production was compared to the one predicted by the model and indicates that the model well reproduces the experimental data. The mean number of produced {phi}{sup 0} per hadronic event was found to be: 0.091 {+-} 0.013, in good agreement with the expected value: 0.091. Next, high momentum {phi}{sup 0} mesons were used for a measurement of the branching ratio of the Z{sup 0} bosons into strange quark pairs: {Gamma}{sub ss}-bar/{Gamma}{sub had}. Three {phi}{sup 0} mesons samples were selected, for which the purity in Z{sup 0}{yields} ss-bar events was greater than 60, 70 and 80 %. For each of these 3 samples, the obtained experimental values are respectively: 0.16 {+-} 0.04, 0.13{+-}0.04 et 0.12{+-}0.05. These values show relatively large uncertainties and indicate an agreement of at the most 2.6 standard deviations to the expected value: 0.22. (author). 63 refs.
Numerical simulation tests with light dynamical quarks
International Nuclear Information System (INIS)
Two generate flavours of quarks are simulated with small masses down to about one fifth of the strange quark mass by using the two-step multi-boson (TSMB) algorithm. The lattice size is 83 . 16 with lattice spacing about a ≅ 0.27 fm which is not far from the Nt = 4 thermodynamical cross-over line. Autocorrelations of different physical quantities are estimated as a function of the quark mass. The eigenvalue spectra of the Wilson-Dirac operator are investigated. (orig.)
On the anomalous mass defect of strange stars in the Field Correlator Method
Pereira, F. I. M.
2016-09-01
We investigate general aspects of the mass defects of strange stars in the context of the Field Correlator Method, without magnetic field. The main parameters of the model that enter the corresponding nonperturbative equation of state of the quark gluon plasma are the gluon condensate G2 and the large distance static Q Q bar potential V1. We calculate mass defects of stellar configurations in the central density range 11 quark-novae explosions.
Strange pathways for black hole formation
International Nuclear Information System (INIS)
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
Strange Matter: a state before black hole
Xu, Renxin
2016-01-01
Normal baryonic matter inside an evolved massive star can be intensely compressed by gravity after a supernova. General relativity predicts formation of a black hole if the core material is compressed into a singularity, but the real state of such compressed baryonic matter (CBM) before an event horizon of black hole appears is not yet well understood because of the non-perturbative nature of the fundamental strong interaction. Certainly, the rump left behind after a supernova explosion could manifest as a pulsar if its mass is less than the unknown maximum mass, $M_{\\rm max}$. It is conjectured that pulsar-like compact stars are made of strange matter (i.e., with 3-flavour symmetry), where quarks are still localized as in the case of nuclear matter. In principle, different manifestations of pulsar-like objects could be explained in the regime of this conjecture. Besides compact stars, strange matter could also be manifested in the form of cosmic rays and even dark matter.
Intrinsic strange distributions in the nucleon from the light-cone models
Salajegheh, Maral
2016-01-01
Precise knowledge of the strange and antistrange quark distributions of the nucleon is a major step toward better understanding of the strong interaction and the nucleon structure. Moreover, the $ s-\\bar s $ asymmetry in the nucleon plays an important role in some physical processes involving hadrons. The goal of this paper is the study of intrinsic strange contribution to the strange sea of the nucleon. To this aim, we calculate the intrinsic strange distributions from the various light-cone models including BHPS, scalar five-quark and meson-baryon models and then compare their results. These models can lead to the rather different distributions for the intrinsic strange that are dominated in different values of $ x $. Furthermore, the meson-baryon model leads to the $ s-\\bar s $ asymmetry that can be comparable in some situations to the result obtained from the global analysis of PDFs. We also present a simple parametrization for each model prediction of intrinsic strange distribution.
QUARK MATTER IN MASSIVE COMPACT STARS
International Nuclear Information System (INIS)
The recent observation of the pulsar PSR J1614-2230 with a mass of 1.97 ± 0.04 Msun gives a strong constraint on the quark and nuclear matter equations of state (EoS). We explore the parameter ranges for a parameterized EoS for quark stars. We find that strange stars, made of absolutely stable strange quark matter, comply with the new constraint only if effects from the strong coupling constant and color-superconductivity are taken into account. Hybrid stars, compact stars with a quark matter core and a hadronic outer layer, can be as massive as 2 Msun, but only for a significantly limited range of parameters. We demonstrate that the appearance of quark matter in massive stars crucially depends on the stiffness of the nuclear matter EoS. We show that the masses of hybrid stars stay below the ones of hadronic and pure quark stars, due to the softening of the EoS at the quark-hadron phase transition.
The Thomas-Fermi Quark Model: Non-Relativistic Aspects
Liu, Quan
2012-01-01
Non-relativistic aspects of the Thomas-Fermi statistical quark model are developed. A review is given and our modified approach to spin in the model is explained. Our results are limited so far to two inequivalent simultaneous wave functions which can apply to multiple degenerate flavors. An explicit spin interaction is introduced, which requires the introduction of a generalized spin "flavor". Although the model is designed to be most reliable for many-quark states, we find surprisingly that it may be used to fit the low energy spectrum of octet and decouplet baryons. The low energy fit allows us to investigate the six-quark doubly strange H-dibaryon state, possible 6 quark nucleon-nucleon resonances and flavor symmetric strange states of higher quark content.
Measuring the sea quark polarization
International Nuclear Information System (INIS)
Spin is a fundamental degree of freedom and measuring the spin structure functions of the nucleon should be a basic endeavor for hadron physics. Polarization experiments have been the domain of fixed target experiments. Over the years large transverse asymmetries have been observed where the prevailing QCD theories predicted little or no asymmetries, and conversely the latest deep inelastic scattering experiments of polarized leptons from polarized targets point to the possibility that little of the nucleon spin is carried by the valence quarks. The possibility of colliding high luminosity polarized proton beams in the Brookhaven Relativistic Heavy Ion Collider (RHIC) provides a great opportunity to extend these studies and systematically probe the spin dependent parton distributions specially to those reactions that are inaccessible to current experiments. This presentation focuses on the measurement of sea quark and possibly the strange quark polarization utilizing the approved RHIC detectors
Magnetic field effects on some astrophysical properties of Quark Stars
Paret, D Manreza
2010-01-01
This thesis aims to study how amending certain astrophysical observable of quark stars due to presence of magnetic field. To do this we need to obtain Equation of State (EOS) and consider the stability of Strange Quark Matter (made up of quarks u, d and s) cold dense and magnetized in stellar equilibrium (beta equilibrium, conservation of the baryonic number and charge neutrality). We will work using the phenomenological MIT Bag model. The stability of the Magnetized Strange Quark Matter (MSQM) is studied taking into account the variation of parameters from the model: s quark mass, baryonic density, magnetic field and the Bag parameter. Results obtained were compared with those of magnetized normal quark matter (only u and d quarks in beta equilibrium) as well as the Strange Quark Matter (SQM). It is found that the energy per baryon decreases with the increasing magnetic field which implies that the MSQM is more stable than SQM. The Equations of State previously obtained are used to obtain stable configuratio...
Self-similarity of strangeness production in pp collisions at RHIC
Czech Academy of Sciences Publication Activity Database
Tokarev, M. V.; Zborovský, Imrich
Vol. 668. Bristol: IOP Publishing Ltd., 2016, s. 012087. ISSN 1742-6588. [15th International Conference on Strangeness in Quark Matter (SQM). Dubna (RU), 06.07.2015-11.07.2015] R&D Projects: GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : transverse momentum spectra * STAR collaboration * PHENIX collaboration Subject RIV: BE - Theoretical Physics
Neutron stars, strange stars, and the nuclear equation of state
Energy Technology Data Exchange (ETDEWEB)
Weber, F.; Glendenning, N.K.
1992-11-02
This article consists of three parts. In part one we review the present status of dense nuclear matter calculations, and introduce a representative collection of realistic nuclear equations of state which are derived for different assumptions about the physical behavior of dense matter (baryon population, pion condensation,.possible transition of baryon matter to quark matter). In part two we review recently performed non-rotating and rotating compact star calculations performed for these equations of state. The minimum stable rotational periods of compact stars, whose knowledge is of decisive importance for the interpretation of rapidly rotating pulsars, axe determined. For this purpose two different limits on stable rotation are studied: rotation at the general relativistic Kepler period (below which mass shedding at the star`s equator sets in), and, secondly, rotation at the gravitational radiation-reaction instability (at which emission of gravitational waves set in which slows the star down). Part three of this article deals with the properties of hypothetical strange stars. Specifically we investigate the amount of nuclear solid crust that can be carried by a rotating strange star, and answer the question whether such objects can give rise to the observed phenomena of pulsar glitches, which is at the present time the only astrophysical test of the strange-quark-matter hypothesis.
Neutron stars, strange stars, and the nuclear equation of state
Energy Technology Data Exchange (ETDEWEB)
Weber, F.; Glendenning, N.K.
1992-11-02
This article consists of three parts. In part one we review the present status of dense nuclear matter calculations, and introduce a representative collection of realistic nuclear equations of state which are derived for different assumptions about the physical behavior of dense matter (baryon population, pion condensation,.possible transition of baryon matter to quark matter). In part two we review recently performed non-rotating and rotating compact star calculations performed for these equations of state. The minimum stable rotational periods of compact stars, whose knowledge is of decisive importance for the interpretation of rapidly rotating pulsars, axe determined. For this purpose two different limits on stable rotation are studied: rotation at the general relativistic Kepler period (below which mass shedding at the star's equator sets in), and, secondly, rotation at the gravitational radiation-reaction instability (at which emission of gravitational waves set in which slows the star down). Part three of this article deals with the properties of hypothetical strange stars. Specifically we investigate the amount of nuclear solid crust that can be carried by a rotating strange star, and answer the question whether such objects can give rise to the observed phenomena of pulsar glitches, which is at the present time the only astrophysical test of the strange-quark-matter hypothesis.
Neutron stars, strange stars, and the nuclear equation of state
International Nuclear Information System (INIS)
This article consists of three parts. In part one we review the present status of dense nuclear matter calculations, and introduce a representative collection of realistic nuclear equations of state which are derived for different assumptions about the physical behavior of dense matter (baryon population, pion condensation,.possible transition of baryon matter to quark matter). In part two we review recently performed non-rotating and rotating compact star calculations performed for these equations of state. The minimum stable rotational periods of compact stars, whose knowledge is of decisive importance for the interpretation of rapidly rotating pulsars, axe determined. For this purpose two different limits on stable rotation are studied: rotation at the general relativistic Kepler period (below which mass shedding at the star's equator sets in), and, secondly, rotation at the gravitational radiation-reaction instability (at which emission of gravitational waves set in which slows the star down). Part three of this article deals with the properties of hypothetical strange stars. Specifically we investigate the amount of nuclear solid crust that can be carried by a rotating strange star, and answer the question whether such objects can give rise to the observed phenomena of pulsar glitches, which is at the present time the only astrophysical test of the strange-quark-matter hypothesis
International Nuclear Information System (INIS)
In the quark model, the proton is described as a system of three quarks UUD. However, recent experiments (CERN, SLAC) have shown that the strange quarks may contribute in a significant way to the mass and the spin of the proton. The HAPPEX experiment gives one further knowledge about the question of the role the strange quarks play inside the proton. It measures parity violating asymmetry in the scattering of polarized electrons from a proton because the latter is sensitive to the contribution of the strange quarks to the electromagnetic form factors of the nucleon. The observed asymmetry is in the order of a few ppm (part per million). The main difficulty of the experiment is to identify, to estimate and to minimize, as much as possible, all the systematic effects which could give rise to false asymmetries. This thesis discusses the principle of the HAPPEX experiment, its implementation at the Jefferson Lab (JLab), the processing and the analysis of the data, the systematic errors, and finally presents the result of the first data taking (1999) and its present interpretation. The HAPPEX experiment has measured, at Q2 = 0.5 (GeV/c)2, a strange quarks contribution of (1.0 ± 2.3)% to the electromagnetic form factors of the nucleon. The statistics and the systematic effects (measure of the electron beam polarization and knowledge of the neutron electric form factor) contribute equally to the error. (author)
Production and decay of heavy top quarks
International Nuclear Information System (INIS)
Experimental evidence indicates that the top quark exists and has a mass between 50 and 200 GeV/c2. The decays of a top quark with a mass in this range are studied with emphasis placed on the mass region near the threshold for production of real W bosons. Topics discussed are: (1) possible enhancement of strange quark production when MW + ms t W + mb; (2) exclusive decays of T mesons to B and B* mesons using the non-relativistic quark model; (3) polarization of intermediate W's in top quark decay as a source of information on the top quark mass. The production of heavy top quarks in an e+e- collider with a center-of-mass energy of 2 TeV is studied. The effective-boson approximation for photons, Z0's and W's is reviewed and an analogous approximation for interfaces between photons and Z0's is developed. The cross sections for top quark pair production from photon-photon, photon-Z0, Z0Z0, and W+W- fusion are calculated using the effective-boson approximation. Production of top quarks along with anti-bottom quarks via γW+ and Z0W+ fusion is studied. An exact calculation of γe+ → bar νt bar b is made and compared with the effective-W approximation. 31 refs., 46 figs
Determination of light quark masses in QCD
Dominguez, C A
2010-01-01
The standard procedure to determine (analytically) the values of the quark masses is to relate QCD two-point functions to experimental data in the framework of QCD sum rules. In the case of the light quark sector, the ideal Green function is the pseudoscalar correlator which involves the quark masses as an overall multiplicative factor. For the past thirty years this method has been affected by systematic uncertainties originating in the hadronic resonance sector, thus limiting the accuracy of the results. Recently, a major breakthrough has been made allowing for a considerable reduction of these systematic uncertainties and leading to light quark masses accurate to better than 8%. This procedure will be described in this talk for the up-, down-, strange-quark masses, after a general introduction to the method of QCD sum rules.
Radial Correlations between two quarks
Green, A M; Pennanen, P; Michael, C
2001-01-01
In nuclear many-body problems the short-range correlation between two nucleons is well described by the corresponding correlation in the {two}-body problem. Therefore, as a first step in any attempt at an analogous description of many-quark systems, it is necessary to know the two-quark correlation. With this in mind, we study the light quark distribution in a heavy-light meson with a static heavy quark. The charge and matter radial distributions of these heavy-light mesons are measured on a lattice with a light quark mass about that of the strange quark. Both distributions can be well fitted upto r approx 0.7 fm with the exponential form w_i^2(r), where w_i(r)=A exp(-r/r_i). For the charge(c) and matter(m) distributions r_c approx 0.32(2) fm and r_m \\approx 0.24(2) fm. We also discuss the normalisation of the total charge (defined to be unity in the continuum limit) and matter integrated over all space, finding 1.30(5) and 0.4(1) respectively for a lattice spacing approx 0.17 fm.
Centrality Dependence of Azimuthal Anisotropy of Strange Hadrons in 200 GeV Au+Au Collisions
Oldenburg, M
2006-01-01
Measurements of azimuthal anisotropy for strange and multi-strange hadrons are presented for the first time in their centrality dependence. The high statistics results of v2(pT) allow for a more detailed comparison to hydrodynamical model calculations. Number-of-constituent-quark scaling was tested for different centrality classes separately. Higher order anisotropies like v4(pT) are measured for multi-strange hadrons. While we observe agreement between measured data and models a deeper understanding and refinement of the models seem to be necessary in order to fully understand the details of the data.
Neutral strangeness production with the ZEUS detector at HERA
International Nuclear Information System (INIS)
The inclusive production of the neutral strange particles, Λ, anti Λ and K0S 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 Λ to anti Λ asymmetry was observed. The relative yield of Λ and K0S 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 K0SK0S Bose-Einstein correlation measurement gives a result consistent with those from LEP measurements. The Λ polarizations were measured to be consistent with zero for HERA I data. (orig.)
Fast pulsars, strange stars: An opportunity in radio astronomy
International Nuclear Information System (INIS)
The world's data on radio pulsars is not expected to represent the underlying pulsar population because of a search bias against detection of short periods, especially below 1 ms. Yet pulsars in increasing numbers with periods right down to this limit have been discovered suggesting that there may be even shorter ones. If pulsars with periods below 1/2 ms were found, the conclusion that the confined hadronic phase of nucleons and nuclei is only metastable would be almost inescapable. The plausible ground state in that event is the deconfined phase of (3-flavor) strange-quark-matter. From the QCD energy scale this is as likely a ground state as the confined phase. We show that strange matter as the ground state is not ruled out by any known fact, and most especially not by the fact that the universe is in the confined phase. 136 refs
Strange magnetic moments of octet baryons under SU(3) breaking
Institute of Scientific and Technical Information of China (English)
CAO Lu; WANG Biao; CHEN Hong
2012-01-01
Magnetic moments of octet baryons are parameterized to all orders of the flavor SU(3) breaking with the irreducible tensor technique in order to extract the contribution of each flavor quark to the magnetic moments of the octet baryons.The not-yet measured magnetic moment of Σ0 is predicted to be 0.649 μN.Our parameterized forms for the magnetic moments are explicitly flavor-dependent,and hence each flavor component of the magnetic moments can be evaluated directly via the flavor projection operator.It is fouud that the strange magnetic moment of the nucleon is suppressed due to the small isoscalar anomalous magnetic moment of the nucleon.In particular,the strange magnetic form factor of the nucleon turns out to be positive,(G(s)N) (0) =0.428 μN,which is consistent with recent data.
DEFF Research Database (Denmark)
Leer, Jonatan; Kjær, Katrine Meldgaard
chefs Jamie Oliver and Gordon Ramsay imagine, meet and evaluate the ‘other’ food cultures in these programs, paying special attention to how the encounter with the local Indian and Italian is imagined to be a gateway to an authentic and/or primitive experience. To unpack the programs and the experiences...... unpacking cultural encounters, and show how we have used it to deconstruct how ‘authentic’ food is done and met in Gordon's Great Escape and Jamie's Italian Escape. In doing so, we will argue that this way of reading cultural encounters ultimately opens for an alternative understanding of the central......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...
Steinheimer, J.; Sturm, C.; Schramm, S.; Stöcker, H.
2010-09-01
Adjacent to the existing accelerator complex of the GSI Helmholtz Centre for Heavy Ion Research at Darmstadt, Germany, the Facility for Antiproton and Ion Research (FAIR) substantially expands research goals and technical possibilities. It will provide worldwide unique accelerator and experimental facilities allowing for a large variety of unprecedented fore-front research in hadron, nuclear and atomic physics as well as applied sciences which will be described briefly in this paper. The start version of FAIR, the so-called Modularized Start Version, will deliver first beams in 2017/2018. As an example the paper presents research efforts on strangeness at FAIR using heavy ion collisions, exotic nuclei from fragmentation and antiprotons to tackle various topics in this area. In particular hypernuclei and metastable exotic multi-hypernuclear objects will be investigated.
W plus Heavy Quark Production at the Tevatron
Giele, W. T.; Keller, S.; Laenen, and E.
1996-01-01
We present the next-to-leading order QCD corrections to the production of a $W$-boson in association with a jet containing a heavy quark. The calculation is fully differential in the final state particle momenta and includes the mass of the heavy quark. We study for the case of the Tevatron the sensitivity of the cross section to the strange quark distribution function, the dependence of the cross section on the heavy quark mass, the transverse momentum distribution of the jet containing the ...
Nucleon axial and tensor charges with dynamical overlap quarks
Yamanaka, N; Hashimoto, S; Kaneko, T
2015-01-01
We report on our calculation of the nucleon axial and tensor charges in 2+1-flavor QCD with dynamical overlap quarks. Gauge ensembles are generated at a single lattice spacing 0.12 fm and at a strange quark mass close to its physical value. We employ the all-mode-averaging technique to calculate the relevant nucleon correlation functions, and the disconnected quark loop is efficiently calculated by using the all-to-all quark propagator. We present our preliminary results for the isoscalar and isovector charges obtained at pion masses $m_\\pi$ = 450 and 540 MeV.
International Nuclear Information System (INIS)
The most important particle accelerators that can contribute to quark production efforts are overviewed. The history of the discovery of quark particles is outlined. The so-called y-particles were found with 9460 MeV mass in 1977, the new particle was called beauty quark. The tau-particles were discovered in 1975. The most important features of the new generation of particles, the quark family are discussed. (R.P.)
Searches for a possible strangeness S = -2 dibaryon
International Nuclear Information System (INIS)
Since the advent of QCD there has been a strong interest in manifestations of quark degrees of freedom in medium energy nuclear and particle physics. Within the framework of multiquark states the emphasis has centered on states with more than three quarks bound by colour forces rather than by the conventional mesonic forces. Dibaryon systems have played an important role within that framework. One of the most spectacular and exciting predictions is the possible existence, according to the MIT bag model, of a stable, flavor-singlet, strangeness = -2,J/sup P/ = 0+ dihyperon, called by R. Jaffe the H particle. It is a six-quark object (2u, 2d, 2s quarks) with a predicted mass around 2150 MeV, i.e., below the ΛΛ mass with a binding energy around 80 MeV. Its decay channels would be restricted to ΣN and ΛN, via the weak interaction. The relevant two body states are shown. A similar prediction was obtained on the basis of the same model by Mulders et al., with a mass of 2164 MeV for this state. For completeness it should be mentioned that in a recent estimate of the center-of-mass correction to the static MIT bag model, the authors suggest that the dilambda mass moves up to just above the ΛΛ threshold. These calculations are undergoing further tets. Although all these results come from a specific model, Lipkin has argued that the general features of QCD and the known baryon mass splittings imply that the six-quark state with charge zero, spin zero, and strangeness = -2 would have the greatest binding potential
Properties of light quarks from lattice QCD simulations1
International Nuclear Information System (INIS)
By numerical study of the simple bound states of light quarks, in particular the π and K mesons, we are able to deduce fundamental quark properties. Using the 'improved staggered' discretization of QCD, the MILC Collaboration has performed a series of simulations of these bound states, including the effects of virtual quark-antiquark pairs ('sea' quarks). From these simulations, we have determined the masses of the up, down, and strange quarks. We find that the up quark mass is not zero (at the 10 sigma level), putting to rest a twenty-year-old suggestion that the up quark could be massless. Further, by studying the decays of the π and K mesons, we are able to determine the 'CKM matrix element' Vus of the Weak Interactions. The errors on our result for Vus are comparable to the best previous determinations using alternative theoretical approaches, and are likely to be significantly reduced by simulations now in progress
Quark scalar, axial, and pseudoscalar charges in the Schwinger-Dyson formalism
Yamanaka, Nodoka; Imai, Shotaro; Doi, Takahiro M.; Suganuma, Hideo
2014-01-01
We calculate the scalar, axial, and pseudoscalar charges of the quark in the Schwinger-Dyson formalism of Landau gauge QCD. It is found that the dressed quark scalar density of the valence quark is significantly enhanced against the bare quark contribution, and the result explains qualitatively the phenomenologically known value of the pion-nucleon sigma term and also that given by lattice QCD. Moreover, we show that the Richardson's interquark potential suppresses the quark scalar density in...
Strange particle production in hadronic Z{sup 0} decays
Energy Technology Data Exchange (ETDEWEB)
Baird, K.G. III
1996-04-01
A study has been made of neutral strange baryons and pseudoscalar mesons produced in hadronic decays of the weak gauge boson V. The experiment was performed at the Stanford Linear Accelerator Center, which has the unique capability of colliding highly polarized electrons with unpolarized positrons. Overall production rates and spectra of the K{sup 0} and the {Lambda}{sup 0} (+{Lambda}{sup 0}) were measured and compared with other experiments as well as with Quantum Chromodynamics calculations. The combination of the small, stable beam spots produced by the SLAC Linear Collider (SLC) and the precision vertexing capabilities of the SLC Large Detector (SLD) permitted the separation of the hadronic events into three quark flavor-enriched samples. An unfolding was performed to obtain flavor-pure samples, and for the first time measurements were made of K{sup 0} and {Lambda}{sup 0} (+{Lambda}{sup 0}) production rates and spectra in uds, c, and b quark events at the Z{sup 0} pole. This measurement revealed significant production differences. Utilizing the large quark production asymmetry due to the polarized electron beam, high-purity quark and antiquark jet samples were obtained. The first measurement of production differences of the {Lambda}{sup 0} baryon in quark and antiquark jets was performed, which provided clear evidence for a leading particle effect at high momenta.
Strange and charm baryon masses with two flavors of dynamical twisted mass fermions
Energy Technology Data Exchange (ETDEWEB)
Alexandrou, C. [Univ. of Cyprus, Nicosia (Cyprus). Dept. of Physics; Cyprus Institute, Nicosia (Cyprus). Computation-Based Science and Technology Research Center; Carbonell, J. [CEA-Saclay, Gif-sur-Yvette (France). IRFU/Service de Physique Nucleaire; Christaras, D.; Gravina, M. [Univ. of Cyprus, Nicosia (Cyprus). Dept. of Physics; Drach, V. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Papinutto, M. [UFJ/CNRS/IN2P3, Grenoble (France). Laboratoire de Physique Subatomique et Cosmologie; Universidad Autonoma de Madrid (Spain). Dept. de Fisica Teorica; Universidad Autonoma de Madrid UAM/CSIC (Spain). Inst. de Fisica Teorica
2012-10-15
The masses of the low-lying strange and charm baryons are evaluated using two degenerate flavors of twisted mass sea quarks for pion masses in the range of about 260 MeV to 450 MeV. The strange and charm valence quark masses are tuned to reproduce the mass of the kaon and D-meson at the physical point. The tree-level Symanzik improved gauge action is employed. We use three values of the lattice spacing, corresponding to {beta}=3.9, {beta}=4.05 and {beta}=4.2 with r{sub 0}/a=5.22(2), r{sub 0}/a=6.61(3) and r{sub 0}/a=8.31(5) respectively. We examine the dependence of the strange and charm baryons on the lattice spacing and strange and charm quark masses. The pion mass dependence is studied and physical results are obtained using heavy baryon chiral perturbation theory to extrapolate to the physical point.
Strange particles: A probe of new physics in particles and nuclei
International Nuclear Information System (INIS)
Nuclear and also partially particle physics with strangeness is surveyed with emphasis on the following points: In Λ and Σ hypernuclei one can determine the hyperon-nucleus interaction and learn something on the spin-orbit strength of the hyperon-nucleus potential. This yields information on the hyperon-nucleon interaction. Not understood is the small width of the Σ-hypernuclei. From doubly strange nuclei one could learn something about the hyperon-hyperon interaction and get information about the reaction dynamics of double strangeness exchange reactions. An especially interesting double strange system is the H-Dibaryon which has the quark content of two Λ's. Is this system bound below the ΛΛ threshold? The proton-antiproton reaction going to lambda-antilambda which is studied at LEAR gives information about the proton-antiproton annihilation mechanism and the creation of a strange-antistrange quark pair. On the long run, one should also think of looking for charmed hypernuclei. The K+ meson is the weak interacting particle of the strong interaction. Thus, one can probe matter distribution of a nucleus even deep inside, similar to the electron-nucleus scattering which maps the charge distributions of the nuclei. As a last point, quark-gluon spectroscopy is discussed at the example of the Λ*(3/2-; 1520 MeV). Reactions with strange projectiles can probe the nature of the wave functions of different baryonic and hadronic excited states. In the same way one was probing in nuclear physics the nature of different states by exciting them in projectile nucleus scattering and measuring the di-excitation gamma rays. (orig.)
QCD thermodynamics with three flavors of improved staggered quarks
International Nuclear Information System (INIS)
We report on a study of QCD thermodynamics with three flavors of quarks, using a Symanzik improved gauge action and the Asqtad O(a2) improved staggered quark action. Simulations were carried out with lattice spacings 1/4T, 1/6T, and 1/8T both for three degenerate quarks with masses less than or equal to the strange quark mass ms and for degenerate up and down quarks with masses in the range 0.1ms≤mu,d≤0.6ms and the strange quark mass fixed near its physical value. We present results for standard thermodynamics quantities, such as the Polyakov loop, the chiral order parameter and its susceptibility. For the quark masses studied to date we find a rapid crossover rather than a bona fide phase transition. We have carried out the first calculations of quark number susceptibilities with three flavors of sea quarks. These quantities are of physical interest because they are related to event-by-event fluctuations in heavy ion collision experiments. Comparison of susceptibilities at different lattice spacings show that our results are close to the continuum values
Higher twist effects in charmed-strange νDIS diffraction
International Nuclear Information System (INIS)
The non-conservation of charmed-strange current in the neutrino deep inelastic scattering (νDIS) strongly affects the longitudinal structure function, FL, at small values of Bjorken x. The corresponding correction to FL is a higher twist effect enhanced at small x by the rapidly growing gluon density factor. As a result, the component of FL induced by the charmed-strange current prevails over the light-quark component and dominates FL=FLcs+FLud at x≤0.01 and Q2∼mc2. The color dipole analysis clarifies the physics behind the phenomenon and provides a quantitative estimate of the effect.
Quark flavor tagging in polarized hadronic processes
International Nuclear Information System (INIS)
We describe a general approach to quark flavor tagging in polarized hadronic processes, with particular emphasis on semi-inclusive deep inelastic scattering. A formalism is introduced that allows one to relate chosen quark flavor polarizations to an arbitrary combination of final-state hadron spin asymmetries. Within the context of the presented formalism, we quantify the sensitivity of various semi-inclusive hadron asymmetries to the light quark flavors. We show that unpolarized Λ close-quote s may allow one to measure strange quark and antiquark polarizations independently. We also highlight several applications of our formalism, particularly to measurements intended to probe further the spin structure of the nucleon. copyright 1998 The American Physical Society
Determination of strange sea distributions from νN deep inelastic scattering
International Nuclear Information System (INIS)
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 Bμ=(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 κ(Q2=20 GeV2)=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 Q2=20 GeV2). (orig.)
Relativistic three-body quark model of light baryons based on hypercentral approach
International Nuclear Information System (INIS)
In this paper, we have treated the light baryons as a relativistic three-body bound system. Inspired by lattice QCD calculations, we treated baryons as a spin-independent three-quark system within a relativistic three-quark model based on the three-particle Klein–Gordon equation. We presented the analytical solution of three-body Klein–Gordon equation with employing the constituent quark model based on a hypercentral approach through which two- and three-body forces are taken into account. Herewith the average energy values of the up, down and strange quarks containing multiplets are reproduced. To describe the hyperfine structure of the baryon, the splittings within the SU(6)-multiplets are produced by the generalized Gursey Radicati mass formula. The considered SU(6)-invariant potential is popular “Coulomb-plus-linear” potential and the strange and non-strange baryons spectra are in general well reproduced. (author)
Quark Interchange Model of Baryon Interactions.
Maslow, Joel Neal
The strong interactions at low energy are traditionally described by meson field theories treating hadrons as point -like particles. Here a mesonic quark interchange model (QIM) is presented which takes into account the finite size of the baryons and the internal quark structure of hadrons. The model incorporates the basic quark-gluon coupling of quantum chromodynamics (QCD) and the MIT bag model for color confinement. Because the quark-gluon coupling constant is large and we assume that confinement excludes overlap of hadronic quark bags except at high momenta, a non-perturbative method of nuclear interactions is presented. The QIM allows for exchange of quark quantum numbers at the bag boundary between colliding hadrons mediated at short distances by a gluon exchange between two quarks within the hadronic interior. This generates, via a Fierz transformation, an effective space-like t channel exchange of color singlet (qq) states that can be identified with the low lying meson multiplets. Thus, a one boson exchange (OBE) model is obtained that allows for comparison with traditional phenomenological models of nuclear scattering. Inclusion of strange quarks enables calculation of Yn scattering. The NN and YN coupling constants and the nucleon form factors show good agreement with experimental values as do the deuteron low energy data and the NN low energy phase shifts. Thus, the QIM provides a simple model of strong interactions that is chirally invariant, includes confinement and allows for an OBE form of hadronic interaction at low energies and momentum transfers.
Quark interchange model of baryon interactions
International Nuclear Information System (INIS)
The strong interactions at low energy are traditionally described by meson field theories treating hadrons as point-like particles. Here a mesonic quark interchange model (QIM) is presented which takes into account the finite size of the baryons and the internal quark structure of hadrons. The model incorporates the basic quark-gluon coupling of quantum chromodynamics (QCD) and the MIT bag model for color confinement. Because the quark-gluon coupling constant is large and it is assumed that confinement excludes overlap of hadronic quark bags except at high momenta, a non-perturbative method of nuclear interactions is presented. The QIM allows for exchange of quark quantum numbers at the bag boundary between colliding hadrons mediated at short distances by a gluon exchange between two quarks within the hadronic interior. This generates, via a Fierz transformation, an effective space-like t channel exchange of color singlet (q anti-q) states that can be identified with the low lying meson multiplets. Thus, a one boson exchange (OBE) model is obtained that allows for comparison with traditional phenomenological models of nuclear scattering. Inclusion of strange quarks enables calculation of YN scattering. The NN and YN coupling constants and the nucleon form factors show good agreement with experimental values as do the deuteron low energy data and the NN low energy phase shifts. Thus, the QIM provides a simple model of strong interactions that is chirally invariant, includes confinement and allows for an OBE form of hadronic interaction at low energies and momentum transfers
Quark interchange model of baryon interactions
Energy Technology Data Exchange (ETDEWEB)
Maslow, J.N.
1983-01-01
The strong interactions at low energy are traditionally described by meson field theories treating hadrons as point-like particles. Here a mesonic quark interchange model (QIM) is presented which takes into account the finite size of the baryons and the internal quark structure of hadrons. The model incorporates the basic quark-gluon coupling of quantum chromodynamics (QCD) and the MIT bag model for color confinement. Because the quark-gluon coupling constant is large and it is assumed that confinement excludes overlap of hadronic quark bags except at high momenta, a non-perturbative method of nuclear interactions is presented. The QIM allows for exchange of quark quantum numbers at the bag boundary between colliding hadrons mediated at short distances by a gluon exchange between two quarks within the hadronic interior. This generates, via a Fierz transformation, an effective space-like t channel exchange of color singlet (q anti-q) states that can be identified with the low lying meson multiplets. Thus, a one boson exchange (OBE) model is obtained that allows for comparison with traditional phenomenological models of nuclear scattering. Inclusion of strange quarks enables calculation of YN scattering. The NN and YN coupling constants and the nucleon form factors show good agreement with experimental values as do the deuteron low energy data and the NN low energy phase shifts. Thus, the QIM provides a simple model of strong interactions that is chirally invariant, includes confinement and allows for an OBE form of hadronic interaction at low energies and momentum transfers.
Precision measurements of top quark production with the ATLAS detector
Stolte, Philipp; The ATLAS collaboration
2016-01-01
The top quark is the heaviest known fundamental particle. As it is the only quark that decays before it hadronizes, this gives us the unique opportunity to probe the properties of bare quarks and to test perturbative QCD. This talk will focus on a few recent precision top quark measurements by the ATLAS Collaboration: fiducial top pair and single top production cross sections including differential distributions will be presented and compared with QCD predictions. The results include the first top quark measurements at 13 TeV using data from LHC run 2.
Energy Technology Data Exchange (ETDEWEB)
Schramm, D.N. [Chicago Univ., IL (United States)]|[Fermi National Accelerator Lab., Batavia, IL (United States); Fields, B.; Thomas, D. [Chicago Univ., IL (United States)
1992-01-01
The possible implications of the quark-hadron transition for cosmology are explored. Possible surviving signatures are discussed. In particular, the possibility of generating a dark matter candidate such as strange nuggets or planetary mass black holes is noted. Much discussion is devoted to the possible role of the transition for cosmological nucleosynthesis. It is emphasized that even an optimized first order phase transition will not significantly alter the nucleosynthesis constraints on the cosmological baryon density nor on neutrino counting. However, it is noted that Be and B observations in old stars may eventually be able to be a signature of a cosmologically significant quark-hadron transition. It is pointed out that the critical point in this regard is whether the observed B/Be ratio can be produced by spallation processes or requires cosmological input. Spallation cannot produce a B/Be ratio below 7.6. A supporting signature would be Be and B ratios to oxygen that greatly exceed galactic values. At present, all data is still consistent with a spallagenic origin.
International Nuclear Information System (INIS)
The possible implications of the quark-hadron transition for cosmology are explored. Possible surviving signatures are discussed. In particular, the possibility of generating a dark matter candidate such as strange nuggets or planetary mass black holes is noted. Much discussion is devoted to the possible role of the transition for cosmological nucleosynthesis. It is emphasized that even an optimized first order phase transition will not significantly alter the nucleosynthesis constraints on the cosmological baryon density nor on neutrino counting. However, it is noted that Be and B observations in old stars may eventually be able to be a signature of a cosmologically significant quark-hadron transition. It is pointed out that the critical point in this regard is whether the observed B/Be ratio can be produced by spallation processes or requires cosmological input. Spallation cannot produce a B/Be ratio below 7.6. A supporting signature would be Be and B ratios to oxygen that greatly exceed galactic values. At present, all data is still consistent with a spallagenic origin
The quark gluon plasma: Lattice computations put to experimental test
Indian Academy of Sciences (India)
Sourendu Gupta
2003-11-01
I describe how lattice computations are being used to extract experimentally relevant features of the quark gluon plasma. I deal speciﬁcally with relaxation times, photon emissivity, strangeness yields, event-by-event ﬂuctuations of conserved quantities and hydrodynamic ﬂow. Finally I give evidence that the plasma is rather liquid-like in some ways.
High temperature QCD with three flavors of improved staggered quarks
Bernard, C; DeTar, C E; Gottlieb, S; Gregory, E; Heller, U M; Osborn, J; Sugar, R L; Toussaint, D; Gottlieb, Steven; Gregory, Eric
2002-01-01
We present an update of our study of high temperature QCD with three flavors of quarks, using a Symanzik improved gauge action and the Asqtad staggered quark action. Simulations are being carried out on lattices with Nt=4, 6 and 8 for the case of three degenerate quarks with masses less than or equal to the strange quark mass, $m_s$, and on lattices with Nt=6 and 8 for degenerate up and down quarks with masses in the range 0.2 m_s \\leq m_{u,d} \\leq 0.6 m_s, and the strange quark fixed near its physical value. We also report on first computations of quark number susceptibilities with the Asqtad action. These susceptibilities are of interest because they can be related to event-by-event fluctuations in heavy ion collision experiments. Use of the improved quark action leads to a substantial reduction in lattice artifacts. This can be seen already for free fermions and carries over into our results for QCD.
Gervino, Gianpiero; Lavagno, Andrea; Pigato, Daniele
2012-06-01
We investigate the relativistic equation of state of hadronic matter and quark-gluon plasma at finite temperature and baryon density in the framework of the non-extensive statistical mechanics, characterized by power-law quantum distributions. We impose the Gibbs conditions on the global conservation of baryon number, electric charge and strangeness number. For the hadronic phase, we study an extended relativistic mean-field theoretical model with the inclusion of strange particles (hyperons and mesons). For the quark sector, we employ an extended MIT-Bag model. In this context we focus on the relevance of non-extensive effects in the presence of strange matter.
Gervino, G; Pigato, D
2012-01-01
We investigate the relativistic equation of state of hadronic matter and quark-gluon plasma at finite temperature and baryon density in the framework of the non-extensive statistical mechanics, characterized by power-law quantum distributions. We impose the Gibbs conditions on the global conservation of baryon number, electric charge and strangeness number. For the hadronic phase, we study an extended relativistic mean-field theoretical model with the inclusion of strange particles (hyperons and mesons). For the quark sector, we employ an extended MIT-Bag model. In this context we focus on the relevance of non-extensive effects in the presence of strange matter.
Production of strange particles in hadronization processes
International Nuclear Information System (INIS)
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
On pp → pKΛ, NKΣ, ppϕ — the basic ingredients for strangeness production in heavy ion collisions
International Nuclear Information System (INIS)
The strangeness production in heavy ion collisions was proposed to be probes of the nuclear equation of state, Kaon potential in nuclear medium, strange quark matter and quark-gluon plasma, etc. However, to act as reliable probes, proper understanding of the basic ingredients for the strangeness production, such as pp → pK+Λ, pp → ppϕ and pp → nK+Σ+ is necessary. Recent study of these reactions clearly shows that previously ignored contributions from the spin-parity 1/2- resonances, N*(1535) and Δ*(1620), are in fact very important for these reactions, especially for near-threshold energies. It is necessary to include these contributions for getting reliable calculation for the strangeness production in heavy ion collisions. (author)
Properties of excited charm and charm-strange mesons
Godfrey, Stephen; Moats, Kenneth
2016-02-01
We calculate the properties of excited charm and charm-strange mesons. We use the relativized quark model to calculate their masses and wave functions that are used to calculate radiative transition partial widths and the 3P0 quark-pair-creation model to calculate their strong decay widths. We use these results to make quark model spectroscopic assignments for recently observed charm and charm-strange mesons. In particular, we find that the properties of the DJ(2550 )0 and DJ*(2600 )0 are consistent with those of the 2 1S0 (c u ¯) and the 2 3S1 (c u ¯) states respectively, and the D1*(2760 )0, D3*(2760 )-,and DJ(2750 )0with those of the 1 3D1 (c u ¯), 1 3D3 (d c ¯), and 1 D2(c u ¯) states respectively. We tentatively identify the DJ*(3000 )0 as the 1 3F4 (c u ¯ ) and favor the DJ(3000 )0 to be the 3 1S0 (c u ¯ ) although we do not rule out the 1 F3 and 1 F3' assignment. For the recently observed charm-strange mesons we identify the Ds1 *(2709 )±,Ds1 *(2860 )-,andDs3 *(2860 )-as the 2 3S1 (c s ¯), 1 3D1 (s c ¯), and 1 3D3 (s c ¯) states respectively and suggest that the Ds J(3044 )± is most likely the Ds 1(2 P1' ) or Ds 1(2 P1) state although it might be the Ds2 *(2 3P2 ) with the D K final state too small to be observed with current statistics. Based on the predicted properties of excited states, that they do not have too large a total width and that they have a reasonable branching ratio to simple final states, we suggest states that should be able to be found in the near future. We expect that the tables of properties summarizing our results will be useful for interpreting future observations of charm and charm-strange mesons.
Event generator analysis for singly strange particle production data
International Nuclear Information System (INIS)
We have used the event generator LUCIAE to analyze the data of singly strange particle production in pp, pA, and AA reactions at 200A GeV and compared them with the corresponding experimental data and theoretical results of HIJING, VENUS, and RQMD. The results indicate that for reproducing the NA35 data of AA reactions it requires a somewhat larger s quark suppression factor (s=0.3) and shorter formation time (τ=1 fm/c) of produced particles than for reproducing the experimental data of pp and pA (s=0.2 and τ=1.5 fm/c). This might be understood intuitively from the relationship between the effective string tension and the violence of collision. However, the NA36 data of the negative multiplicity dependence of Λ in S + Pb reaction at 200 A GeV could not be well reproduced by LUCIAE, VENUS, or RQMD, and the NA36 data prefers model parameters of s=0.2 and τ=1.5 fm/c especially, this seems hard to understand and needs further studies. From comparing the NA35 data of the rapidity distribution of Λ in S + Ag reactions to the corresponding results of LUCIAE one knows that the effect of varying the s quark suppression factor from 0.2 to 0.3 is smaller than the effect of rescattering with respect to strangeness production. copyright 1997 The American Physical Society
International Nuclear Information System (INIS)
The strange axial-vector mesons K1 (1270) and K1 (1400) are reanalyzed in the light of the updated experimental information and compared with the recent result on the Kππ production in τ decay. The mixing angle between the strange mesons of 3P1 and 1P1 is determined by the partial decay rates, and, independently, by the masses. They lead to θK∼33 degree or 57 degree. The observed K1 (1400) production dominance in the τ decay favors θK∼33 degree. Flavor-SU(3) breaking of 20% or so in the production amplitudes can explain quantitatively the observed production ratio
Topics in strangeness nuclear physics
International Nuclear Information System (INIS)
Strangeness nuclear physics bears a broad impact on contemporary physics since it lies at the intersection of nuclear and elementary particle physics, having, moreover, significant implications to the astrophysics of compact objects. This set of extensive lectures presents a balanced theoretical and experimental introduction to, and survey of, the field, addressing topics such as the production and spectroscopy of strange nuclear systems, modern approaches to the hyperon-nucleon interaction, and weak decays of hypernuclei. With new experiments underway, this burgeoning research field is well served by this tutorial primer and review for both newcomers and seasoned researchers alike. (orig.)
International Nuclear Information System (INIS)
A review of strange particle production in heavy ion collisions at ultrarelativistic energies is presented. The particle yields and ratios from SPS and RHIC are discussed in view of the newest developments in understanding collision dynamics, and in view of their role in the search for a quark gluon plasma. A strangeness enhancement, most notably observed in CERN Pb-beam results, shows a remarkable two fold global enhancement with a much larger effect seen in the case of multistrange baryons. Hadronic models did fail to explain this pattern. At RHIC energy strangeness assumes a different role, since temperatures are higher and the central rapidity region almost baryon-free. An intriguing question: 'Did RHIC change the way we understand strangeness production in heavy ion collisions?' is discussed
Multi-strange baryon elliptic flow in Au+Au collisions at sqrt(s_NN)= 200 GeV
Adams, J; Ahammed, Z; Amonett, J; Anderson, B D; Arkhipkin, D; Averichev, G S; Badyal, S K; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Berger, J; Bezverkhny, B I; Bharadwaj, S; Bhasin, A; Bhati, A K; Bhatia, V S; Bichsel, H; Bielcik, J; Bielcikova, J; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Bouchet, J; Brandin, A V; Bravar, A; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca-Sanchez, M; Castillo, J; Catu, O; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Daugherity, M; De Moura, M M; Dedovich, T G; Derevshchikov, A A; Didenko, L; Dietel, T; Dogra, S M; Dong, W J; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta-Majumdar, M R; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Faivre, J; Fatemi, R; Fedorisin, J; Filimonov, K; Filip, P; Finch, E; Fine, V; Fisyak, Yu; Fu, J; Gagliardi, C A; Gaillard, L; Gans, J; Ganti, M S; Geurts, F; Ghazikhanian, V; Ghosh, P; González, J E; Gos, H; Grachov, O; Grebenyuk, O; Grosnick, D P; Guertin, S M; Guo, Y; Sen-Gupta, A; Gutíerrez, T D; Hallman, T J; Hamed, A; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Hepplemann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Huang, H Z; Huang, S L; Hughes, E W; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Jedynak, M; Jiang, H; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kaplan, M; Keane, D; Kechechyan, A; Khodyrev, V Yu; Kiryluk, J; Kisiel, A; Kislov, E M; Klay, J; Klein, S R; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kowalik, K L; Krämer, M; Kravtsov, P; Kravtsov, V I; Krüger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kutuev, R K; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lehocka, S; Le Vine, M J; Li, C; Li, Q; Li, Y; Lin, G; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, L; Liu, Q J; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; López-Noriega, M; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahajan, S; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J N; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Meissner, F; Melnik, Yu M; Meschanin, A; Miller, M L; Minaev, N G; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnár, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Netrakanti, P K; Nikitin, V A; Nogach, L V; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pal, S K; Panebratsev, Yu A; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevozchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M V; Potrebenikova, E V; Potukuchi, B V K S; Prindle, D; Pruneau, C A; Putschke, J; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D M; Reid, J G; Reinnarth, J; Renault, G; Retière, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Sarsour, M; Savin, I; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Schweda, K; Seger, J; Seyboth, P; Shahaliev, E; Shao, M; Shao, W; Sharma, M; Shen, W Q; Shestermanov, K E; Shimansky, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sood, G; Sørensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M N; Stringfellow, B C; Suaide, A A P; Sugarbaker, E R; Suire, C; Sumbera, M; Surrow, B; Swanger, M; Symons, T J M; Szanto de Toledo, A; Toledo; Tai, A; Takahashi, J; Tang, A H; Tarnowsky, T J; Thein, D; Thomas, J H; Timoshenko, S; Tokarev, M; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; Van, M; Leeuwen; Van der Molen, A M; Varma, R; Vasilevski, I M; Vasilev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, X L; Wang, Y; Wang, Z M; Ward, H; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yamamoto, E; Yepes, P; Yurevich, V I; Zborovský, I; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N
2005-01-01
We report on the first measurement of elliptic flow $v_2(p_T)$ of multi-strange baryons $\\Xi+\\bar{Xi}$ and $\\Omega+\\bar{Omega} in heavy-ion collisions. In minimum bias Au+Au collisions at sqrt(s_NN) = 200 GeV, a significant amount of elliptic flow, comparable to other non-strange baryons, is observed for multi-strange baryons which are expected to be particularly sensitive to the dynamics of the partonic stage of heavy-ion collisions. The $p_T$ dependence of $v_2$ of the multi-strange baryons confirms the number of constituent quark scaling previously observed for lighter hadrons. These results support the idea that a substantial fraction of the observed collective motion is developed at the early partonic stage in ultra-relativistic nuclear collisions at RHIC.
$\\pi$N and strangeness sigma terms at the physical point with chiral fermions
Yang, Yi-Bo; Draper, Terrence; Liang, Jian; Liu, Keh-Fei
2015-01-01
Lattice QCD calculation with chiral fermions for the $\\pi$N sigma term $\\sigma_{\\pi N}$ and strangeness sigma term $\\sigma_{sN}$ including chiral interpolation with continuum and volume corrections are provided in this work. We calculate the scalar matrix element for the light/strange quark directly and find $\\sigma_{\\pi N}=44.4(3.2)(4.5)$ MeV with the disconnected insertion part contributing 30(6)(4)%, and $\\sigma_{sN}=32.3(4.7)(4.9)$ MeV, which is somewhat smaller than $\\sigma_{\\pi N}$. The ratio of the strange/light scalar matrix elements $y$ = 0.058(6)(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)
Will strangeness win the prize?
International Nuclear Information System (INIS)
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)
Will Strangeness Win the Prize?
Kapusta, Joseph I.
2000-01-01
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 to first year physics results from RHIC. These predictions are summarized and evaluated.
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.
Strangeness production in ultra-relativistic heavy-ion collisions: Flavour kinetics. Pt. 2
International Nuclear Information System (INIS)
A recently presented model for the non-equilibrium expansion and hadronization of and the strangeness production in a quark-gluon plasma is developed further. The model includes all members of the lowest flavour SU(3) multiplets, the effect of particle evaporation from the surface of the system and a hydrodynamic treatment of the volume expansion. The evaporation and the decay of resonances are found to be equally important for the production of pions and kaons, and to give about 60% of the total yield. If a quark-gluon plasma is formed, the relative strangeness yield is strongly enhanced compared to pp collisions. The predictions of the model are also compared to recent data for nucleus-nucleus collisions. (orig.)
Light quarks with twisted mass fermions
International Nuclear Information System (INIS)
We investigate Wilson twisted mass fermions in the quenched approximation using different definitions of the critical bare quark mass mc to realize maximal twist and, correspondingly, automatic O(a) improvement for physical observables. A particular definition of mc is given by extrapolating the value of mc obtained from the PCAC relation at non-vanishing bare twisted quark mass μ to μ=0. Employing this improved definition of the critical mass the Wilson twisted mass formulation provides the possibility to perform reliable simulations down to very small quark masses with correspondingly small pion masses of mπ∼250 MeV, while keeping the cutoff effects of O(a2) under control
Oscillation: The Key For Understanding Strange Radio Behaviors Of AXP/SGRs
Lin, Meng-Xiang
2015-01-01
We suggest stellar oscillations are responsible for the strange radio behaviors of Anomalous X-ray pulsars and soft Gamma-ray repeaters (AXP/SGRs), within the framework of both solid quark star model and magnetar model. In solid quark star model, the extra voltage provided by oscillations activates the star from under death line to above death line. In magnetar model, oscillations enlarge the radio beam so that increase the possibility to detect it. Later radio emission decays and vanishes as oscillations damp.
Partially quenched study of strange baryon with N{sub f}=2 twisted mass fermions
Energy Technology Data Exchange (ETDEWEB)
Drach, Vincent; Brinet, Mariane; Carbonell, Jaume [UJF, CNRS/IN2P3, INPG, Grenoble (FR). Lab. de Physique Subatomique et de Cosmologie] (and others)
2009-06-15
We present results on the mass of the baryon octet and decuplet using two flavors of light dynamical twisted mass fermions. The strange quark mass is fixed to its physical value from the kaon sector in a partially quenched set up. Calculations are performed for light quark masses corresponding to a pion mass in the range 270-500 MeV and lattice sizes of 2.1 fm and 2.7 fm. We check for cut-off effects and isospin breaking by evaluating the baryon masses at two different lattice spacings. We carry out a chiral extrapolation for the octet baryons and discuss results for the {omega}. (orig.)
Partially quenched study of strange baryon with Nf = 2 twisted mass fermions
Drach, V; Carbonell, J; Alexandrou, Z L C; Korzec, T; Koutsou, G; Baron, R; Guichon, P; Pène, O; Pallante, E; Reker, S; Urbach, C; Jansen, K
2008-01-01
We present results on the mass of the baryon octet and decuplet using two flavors of light dynamical twisted mass fermions. The strange quark mass is fixed to its physical value from the kaon sector in a partially quenched set up. Calculations are performed for light quark masses corresponding to a pion mass in the range 270-500 MeV and lattice sizes of 2.1 fm and 2.7 fm. We check for cut-off effects and isospin breaking by evaluating the baryon masses at two different lattice spacings. We carry out a chiral extrapolation for the octet baryons and discuss results for the Omega.
Nucleon Vector Strangeness Form Factors: Multi-pion Continuum and the OZI Rule
Hammer, H. -W.; Ramsey-Musolf, M. J.
1997-01-01
We estimate the 3 \\pi continuum contribution to the nucleon strange quark vector current form factors, including the effect of a 3 \\pi \\rho \\pi resonance. We find the magnitude of this OZI-violating contribution to be comparable to that of typical OZI-allowed contributions. We also study the isoscalar electromagnetic form factors, and find that the presence of a \\rho \\pi resonance in the multi-pion continuum may generate an appreciable contribution.
Brown, Laurie Mark; Dresden, Max; Hoddeson, Lillian
2009-01-01
Part I. Introduction; 1. Pions to quarks: particle physics in the 1950s Laurie M Brown, Max Dresden and Lillian Hoddeson; 2. Particle physics in the early 1950s Chen Ning Yang; 3. An historian's interest in particle physics J. L. Heilbron; Part II. Particle discoveries in cosmic rays; 4. Cosmic-ray cloud-chamber contributions to the discovery of the strange particles in the decade 1947-1957 George D. Rochester; 5. Cosmic-ray work with emulsions in the 1940s and 1950s Donald H. Perkins; Part III. High-energy nuclear physics; Learning about nucleon resonances with pion photoproduction Robert L. Walker; 7. A personal view of nucleon structure as revealed by electron scattering Robert Hofstadter; 8. Comments on electromagnetic form factors of the nucleon Robert G. Sachs and Kameshwar C. Wali; Part IV. The new laboratory; 9. The making of an accelerator physicist Matthew Sands; 10. Accelerator design and construction in the 1950s John P. Blewett; 11. Early history of the Cosmotron and AGS Ernest D. Courant; 12. Panel on accelerators and detectors in the 1950s Lawrence W. Jones, Luis W. Alvarez, Ugo Amaldi, Robert Hofstadter, Donald W. Kerst, Robert R. Wilson; 13. Accelerators and the Midwestern Universities Research Association in the 1950s Donald W. Kerst; 14. Bubbles, sparks and the postwar laboratory Peter Galison; 15. Development of the discharge (spark) chamber in Japan in the 1950s Shuji Fukui; 16. Early work at the Bevatron: a personal account Gerson Goldhaber; 17. The discovery of the antiproton Owen Chamberlain; 18. On the antiproton discovery Oreste Piccioni; Part V. The Strange Particles; 19. The hydrogen bubble chamber and the strange resonances Luis W. Alvarez; 20. A particular view of particle physics in the fifties Jack Steinberger; 21. Strange particles William Chinowsky; 22. Strange particles: production by Cosmotron beams as observed in diffusion cloud chambers William B. Fowler; 23. From the 1940s into the 1950s Abraham Pais; Part VI. Detection of the
Quark tensor charge and electric dipole moment within the Schwinger-Dyson formalism
Yamanaka, Nodoka; Doi, Takahiro M.; Imai, Shotaro; Suganuma, Hideo
2013-01-01
We calculate the tensor charge of the quark in the QCD-like theory in the Landau gauge using the Schwinger-Dyson formalism. It is found that the dressed tensor charge of the quark is significantly suppressed against the bare quark contribution, and the result agrees qualitatively with the analyses in the collinear factorization approach and lattice QCD. We also analyze the quark confinement effect with the phenomenological strong coupling given by Richardson, and find that this contribution i...
Production rates of strange vector mesons at the Z{sup 0} resonance
Energy Technology Data Exchange (ETDEWEB)
Dima, M.O.
1997-05-01
This dissertation presents a study of strange vector meson production, {open_quotes}leading particle{close_quotes} effect and a first direct measurement of the strangeness suppression parameter in hadronic decays of the neutral electroweak boson, Z{sup 0}. The measurements were performed in e{sup +}e{sup -} 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 {phi} and K*{sup 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*{sup 0} production is studied separately in these samples, and the results show evidence for the {open_quotes}leading particle{close_quotes} effect. The difference between K*{sup 0} production rates at high momentum in quark and antiquark jets yields a first direct measurement of strangeness suppression in jet fragmentation.
Production rates of strange vector mesons at the Z0 resonance
International Nuclear Information System (INIS)
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, Z0. 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
Workshop: Waiting for the top quark
International Nuclear Information System (INIS)
The world of elementary particle physics is eagerly waiting for the top quark, probably the final element of the 'periodic table' of elementary particle constituents. This table consists of two families of weakly interacting particles (leptons) - one series carrying electric charge; the other being electrically neutral - together with a family of quarks carrying electric charge 2/3 (up, charm, top) and a family of charge -1/3 quarks (down, strange, beauty). It was then not surprising that the 1990 Theory Workshop at the DESY Laboratory in Hamburg in October, devoted this time to 'top physics', attracted some 200 physicists, substantially more than previous workshops in the series
Cheshire cat phenomena and quarks in nuclei
International Nuclear Information System (INIS)
The notion of the ''Cheshire Cat'' principle in hadron structure is developed rigorously in (1+1) dimensions and approximately in (3+1) dimensions for up- and down-quark flavor systems. This phenomenon is invoked to address the issue as to whether or not direct quark-gluon signatures can be ''seen'' in low-energy nuclear phenomena. How addition of the third flavor -strangeness- can modify the Cheshire Cat property is discussed. It is proposed that one of the primary objectives of nuclear physics be to probe -and disturb- the ''vacuum'' of the strong interactions (QCD) and that for this purpose the chiral symmetry SU(3)xSU(3) can play a crucial role in normal and extreme conditions. As an illustration, kaon condensation at a density ρ>∼ 3ρ0 is discussed in terms of a toy model and is related to ''cleansing'' of the quark condensates from the vacuum
Effect of Quark Strong Interaction in Phase Transition on Supernova Explosion
Institute of Scientific and Technical Information of China (English)
LAI Xiang-Jun; LUO Zhi-Quan; LIU Jing-Jing; LIU Hong-Lin
2008-01-01
The effect of quark interactions perturbatively to order αc on the conversion, from quark matter to strange quark matter, is studied systematically based on a recent set of current quark masses. The process has a significant effect on increasing the core temperature, the neutrino abundance and the neutrino energies even if there is no quark interaction. Furthermore, with the switch of the strong interaction among quarks, these quantities will increase respectively to some further extents with αc increase. Taking αc = 0.47 as an example, the temperature, the neutrino abundance and the total neutrino energies are further raised by about 10%, 7%, and 20% respectively, which is weakly dependent on the initial temperature. Combining the effect of the current quark mass and the effect of the quark strong interaction, the results of the conversions will greatly enhance the probability of success for a supernova explosion and deeply influence the dynamics of the supernova evolution.
Measurement of the strange - antistrange asymmetry at NLO in QCD from NuTeV dimuon data
International Nuclear Information System (INIS)
A measurement of the asymmetry between the strange and antistrange quark distributions, from a next to leading order QCD analysis of dimuon events measured by the NuTeV experiment at Fermilab is presented. Neutrino charged current events with two muons in the final state provide a direct means for studying charm production and measuring the strange sea. NuTeV's sign selected beam allows independent measurement of the strange and antistrange seas. An improved measurement of the neutrino and antineutrino forward dimuon cross section tables, using the complete charged current event sample for normalization is performed. These tables are then analyzed at NLO to measure the strange and antistrange seas. Detector acceptance is modeled using an NLO charm cross section differential in all variables required. The strange quark distribution is found to have an integrated momentum weighted asymmetry of +0.00196 ± 0.00046 (stat) ± 0.00045 (syst) ± 0.00128 (external). The charm mass is found to be 1.41 ± 0.10 (stat) ± 0.08 (syst) ± 0.12 (external) GeV
Measurement of the strange - antistrange asymmetry at NLO in QCD from NuTeV dimuon data
Energy Technology Data Exchange (ETDEWEB)
Mason, David Alexander
2006-03-01
A measurement of the asymmetry between the strange and antistrange quark distributions, from a next to leading order QCD analysis of dimuon events measured by the NuTeV experiment at Fermilab is presented. Neutrino charged current events with two muons in the final state provide a direct means for studying charm production and measuring the strange sea. NuTeV's sign selected beam allows independent measurement of the strange and antistrange seas. An improved measurement of the neutrino and antineutrino forward dimuon cross section tables, using the complete charged current event sample for normalization is performed. These tables are then analyzed at NLO to measure the strange and antistrange seas. Detector acceptance is modeled using an NLO charm cross section differential in all variables required. The strange quark distribution is found to have an integrated momentum weighted asymmetry of +0.00196 {+-} 0.00046(stat) {+-} 0.00045(syst) {+-} 0.00182(external). The charm mass is found to be 1.41 {+-} 0.10(stat) {+-} 0.08(syst) {+-} 0.12(external) GeV.
Modified Approach for Calculating Four-Quark Condensates
Institute of Scientific and Technical Information of China (English)
ZONG Hong-Shi; SUN Wei-Min
2007-01-01
By differentiating the dressed quark propagator with respect to a variable background field,the linear response of the dressed quark propagator in the presence of the background field can be obtained.From this general method,using the vector background field as an illustration,we extract a general formula for the four-quark condensate〈(0)|:-q(0)γμq(0)-q(0)γμq(0):|0〉.This formula contains the corresponding fully dressed vector vertex. We use this formula to analyze the factorization problem of the four-quark condensate and show that in the bare vertex approximation factorization holds exactly.
Strange functions in real analysis
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...
Chiral Primaries in Strange Metals
Isachenkov, Mikhail(DESY Hamburg, Theory Group, Notkestrasse 85, D-22607 Hamburg, Germany); Kirsch, Ingo; Schomerus, Volker
2014-01-01
It was suggested recently that the study of 1-dimensional QCD with fermions in the adjoint representation could lead to an interesting toy model for strange metals and their holographic formulation. In the high density regime, the infrared physics of this theory is described by a constrained free fermion theory with an emergent N=(2,2) superconformal symmetry. In order to narrow the choice of potential holographic duals, we initiate a systematic search for chiral primaries in this model. We a...
Search for strange dibaryon systems
International Nuclear Information System (INIS)
The authors present preliminary results of an experiment which is being run at the CERN Proton Synchrotron (PS). The experiment is designed to search for dibaryon systems with strangeness -2, produced in the reaction K- + d→K+ + MM at 1.4 GeV/c incident K- momentum. The missing mass (MM) sensitivity ranges from 2.1 up to 2.4 GeV/c2, the resolution being approximately +- 3.5 MeV/c2. (Auth.)
Sitton, Christina M.
2014-01-01
Fragmentation is a basic symptom of loss, and poetry naturally reflects this disjointing and destructive effect. The fracturing within the poetic form reflects the internal and repeated fracturing effects of trauma on one's own life. In this poetry collection, A Strange Kind of Dying, the speaker is bound by the question, "How is it that I can piece myself back together?" The collection of poetry is meant to help the speaker to find healing from the fragmentation through language. The work is...
Bashinsky, S V
1996-01-01
We reduce the problem of many-channel hadron scattering at nonrelativistic energies to calculations on the scale of a few fermis. Having thus disentangled kinematics from interior quark dynamics, we study their interplay when a quark state occurs near a hadronic threshold. Characteristic parameters, such as the observed peak width, the decay width, and the shape of a cross-section itself are highly affected by the threshold. A general pole-form expression for the S-matrix in an arbitrary background is given, and the pole structure of S is examined. We show that at a hadronic threshold two poles in S are generally important. We also classify the S-matrix pole structure considering an example where nonsingular coupled channels are closed at the threshold. The framework of our paper is the P-matrix formalism, which is reviewed and extended for use together with conventional methods of computing quark-gluon dynamics. Results and applications are illustrated for the doubly strange two-baryon system, the detailed a...
Prospects for strangeness measurement in ALICE
International Nuclear Information System (INIS)
The study of strangeness production at LHC will bring significant information on the bulk chemical properties, its dynamics, and the hadronization mechanisms involved at these energies. The ALICE experiment will measure strange particles from topology (secondary vertices) and from resonance decays over a wide range in transverse momentum and shed light on this new QCD regime. These motivations will be presented as well as the identification performance of ALICE for strange hadrons.
Excitations of strange bottom baryons
Woloshyn, R M
2016-01-01
The ground state and first excited state masses of Omega(b) and Omega(bb) baryons are calculated in lattice QCD using dynamical 2+1 flavour gauge fields. A set of baryon operators employing different combinations of smeared quark fields was used in the framework of the variational method. Results for radial excitation energies were confirmed by carrying out a supplementary multiexponential fitting analysis. Comparison is made with quark model calculations.
Institute of Scientific and Technical Information of China (English)
Zhan-Kui Lü; Shi-Wei Wu; Zhi-Cheng Zeng
2009-01-01
Like the investigation of double white dwarf (DWD) systems, strange dwarf (SD) - white dwarf (WD) system evolution in Laser Interferometer Space Antenna (LISA)'s absolute amplitude-frequency diagram is investigated. Since there is a strange quark core inside an SD, SDs' radii are significantly smaller than the value predicted by the standard WD model, which may strongly affect the gravitational wave (GW) signal in the mass-transferring phases of binary systems. We study how an SD-WD binary evolves across LISA's absolute amplitude-frequency diagram. In principle, we provide an executable way to detect SDs in the Galaxy's DWD systems by radically new windows offered by GW detectors.
Spin-orbit inversion of excited heavy quark mesons
International Nuclear Information System (INIS)
The mesonic heavy quark spin multiplets with sscr(l)πscr(l)= (1) /(2) + and (3) /(2) + are expected to be the lowest-lying excitations above the pseudoscalar and vector ground states with sscr(l)πscr(l)= (1) /(2) -. I show that for charm and bottom these multiplets are probably inverted, with the 2+ and 1+ states with sscr(l)πscr(l)= (3) /(2) + about 150MeV below the 1+ and 0+ states with sscr(l)πscr(l)= (1) /(2) +. If verified, such an inversion would both support the expectation that confinement has no dynamical spin-dependence and indicate that heavy- and light-quark systems may be characterized by the same effective low-energy degrees of freedom. As an important by-product, this work establishes the dynamics of the strange quark as a critical link between heavy- and light-quark hadrons, justifying efforts toward a much more complete experimental and theoretical understanding of strange mesons and baryons and of strange quarkonia. copyright 1998 The American Physical Society
Quark and gluon condensates in nuclear matter with Brown- Rho scaling
Institute of Scientific and Technical Information of China (English)
郭华; 杨树; 刘玉鑫
2001-01-01
Quark and gluon condensates in nuclear matter are investigated in a density-dependent relativistic mean-field theory. The in-medium quark condensate decreases rapidly as the density of nu-clear matter increases, if the Brown-Rho scaling is included. The decrease in the in-medium quark condensate with the nuclear matter density is consistent with the result predicted by the partial chiral symmetry restoration. The gluon condensate and the influence of the strange quark contents on the gluon condensate in nuclear matter are discussed.
Flavor structure of $\\Lambda$ baryons from lattice QCD - from strange to charm
Gubler, Philipp; Oka, Makoto
2016-01-01
$\\Lambda$ baryons of spin-parity $\\frac{1}{2}^{\\pm}$ with either a strange or charm valence quark are studied in full 2+1 flavor lattice QCD. Multiple $SU(3)$ singlet and octet operators are employed to generate the desired single baryon states on the lattice. Via the variational method, the couplings of these states to the different operators provide information about the flavor structure of the $\\Lambda$ baryons. We make use of the gauge configurations of the PACS-CS collaboration and chirally extrapolate the results for the masses and $SU(3)$ flavor components to the physical point. We furthermore gradually change the hopping parameter of the heaviest quark from strange to charm to study how the properties of the $\\Lambda$ baryons evolve as a function of the heavy quark mass. It is found that the baryon energy levels increase almost linearly with the quark mass. Meanwhile, the flavor structure of most of the states remains stable, with the exception of the lowest $\\frac{1}{2}^{-}$ state, which changes from...
Physics of the quark - gluon plasma
Energy Technology Data Exchange (ETDEWEB)
NONE
2001-09-01
This document gathers 31 contributions to the workshop on the physics of quark-gluon plasma that took place in Palaiseau in september 2001: 1) gamma production in heavy collisions, 2) BRAHMS, 3) experimental conference summary, 4) modelling relativistic nuclear collisions, 5) microscopic reaction dynamics at SPS and RHIC, 6) direct gamma and hard scattering at SPS, 7) soft physics at RHIC, 8) results from the STAR experiment, 9) quarkonia: experimental possibilities, 10) elliptic flow measurements with PHENIX, 11) charmonium production in p-A collisions, 12) anisotropic flow at the SPS and RHIC, 13) deciphering the space-time evolution of heavy ion collisions with correlation measurements, 14) 2-particle correlation at RHIC, 15) particle spectra at AGS, SPS and RHIC, 16) strangeness production in STAR, 17) strangeness production in Pb-Pb collisions at SPS, 18) heavy ion physics at CERN after 2000 and before LHC, 19) NEXUS guideline and theoretical consistency, 20) introduction to high p{sub T} physics at RHIC, 21) a novel quasiparticle description of the quark-gluon plasma, 22) dissociation of excited quarkonia states, 23) high-mass dimuon and B {yields} J/{psi} production in ultrarelativistic heavy ion collisions, 24) strange hyperon production in p + p and p + Pb interactions from NA49, 25) heavy quarkonium hadron cross-section, 26) a new method of flow analysis, 27) low mass dilepton production and chiral symmetry restoration, 28) classical initial conditions for nucleus-nucleus collisions, 29) numerical calculation of quenching weights, 30) strangeness enhancement energy dependence, and 31) heavy quarkonium dissociation.
Physics of the quark - gluon plasma
International Nuclear Information System (INIS)
This document gathers 31 contributions to the workshop on the physics of quark-gluon plasma that took place in Palaiseau in september 2001: 1) gamma production in heavy collisions, 2) BRAHMS, 3) experimental conference summary, 4) modelling relativistic nuclear collisions, 5) microscopic reaction dynamics at SPS and RHIC, 6) direct gamma and hard scattering at SPS, 7) soft physics at RHIC, 8) results from the STAR experiment, 9) quarkonia: experimental possibilities, 10) elliptic flow measurements with PHENIX, 11) charmonium production in p-A collisions, 12) anisotropic flow at the SPS and RHIC, 13) deciphering the space-time evolution of heavy ion collisions with correlation measurements, 14) 2-particle correlation at RHIC, 15) particle spectra at AGS, SPS and RHIC, 16) strangeness production in STAR, 17) strangeness production in Pb-Pb collisions at SPS, 18) heavy ion physics at CERN after 2000 and before LHC, 19) NEXUS guideline and theoretical consistency, 20) introduction to high pT physics at RHIC, 21) a novel quasiparticle description of the quark-gluon plasma, 22) dissociation of excited quarkonia states, 23) high-mass dimuon and B → J/Ψ production in ultrarelativistic heavy ion collisions, 24) strange hyperon production in p + p and p + Pb interactions from NA49, 25) heavy quarkonium hadron cross-section, 26) a new method of flow analysis, 27) low mass dilepton production and chiral symmetry restoration, 28) classical initial conditions for nucleus-nucleus collisions, 29) numerical calculation of quenching weights, 30) strangeness enhancement energy dependence, and 31) heavy quarkonium dissociation
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.)
Can Doubly Strange Dibaryon Resonances be Discovered at RHIC?
Paganis, S D; Ray, R L; Tang, J L; Udagawa, T; Longacre, R S
2000-01-01
The baryon-baryon continuum invariant mass spectrum generated from ultrarelativistic 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 Lambda-Lambda and/or proton-Cascade-minus, 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 sensit...
Full nonperturbative QCD simulations with 2+1 flavors of improved staggered quarks
Bazavov, A; DeTar, C; Gottlieb, Steven; Heller, U M; Hetrick, J E; Laiho, J; Levkova, L; MacKenzie, P B; Oktay, M B; Sugar, R; Toussaint, D; Van de Water, R S
2009-01-01
For several years the MILC collaboration has carried out nonperturbative simulations of full QCD with two degenerate flavors of light quarks, up and down, and with one heavier flavor, the strange quark. Several light quark masses, down to about three times the physical light quark mass, and several lattice spacings have been used. These allow for controlled continuum and chiral extrapolations of many low energy QCD observables. Use of an improved staggered quark formalism, "asqtad" fermions, has been crucial in achieving this goal. Here we review the improved staggered formalism, emphasizing both advantages and drawbacks. In particular, we review the procedure, known as the "fourth root trick" for removing unwanted staggered species in the continuum limit. We then describe the lattice ensembles created so far, and the physics results obtained on them. These include the heavy quark potential, spectrum of light hadrons, quark masses, decay constants of light and heavy-light pseudoscalar mesons, semileptonic for...
Parton Distribution in Pseudoscalar Mesons with a Light-Front Constituent Quark Model
de Melo, J P B C; Tsushima, Kazuo
2015-01-01
We compute the distribution amplitudes of the pion and kaon in the light-front constituent quark model with the symmetric quark-bound state vertex function. In the calculation we explicitly include the flavor-SU(3) symmetry breaking effect in terms of the constituent quark masses of the up (down) and strange quarks. To calculate the kaon parton distribution functions~(PDFs), we use both the conditions in the light-cone wave function, i.e., when $\\bar{s}$ quark is on-shell, and when $u$ quark is on-shell, and make a comparison between them. The kaon PDFs calculated in the two different conditions clearly show asymmetric behaviour due to the flavor SU(3)-symmetry breaking implemented by the quark masses.
International Nuclear Information System (INIS)
We discuss the results accumulated during the last five years in heavy quark physics and try to draw a simple general picture of the present situation. The survey is based on a unified point of view resulting from quantum chromodynamics. (orig.)
A new estimate of the quark masses
International Nuclear Information System (INIS)
Assuming chiral symmetry breaking is due to a quark mass term, and some particular combinations of the lowest-lying meson states belong to the octet representation of the chiral algebra of the observable light plane charges, one finds for the bare quark masses the (approximate) formulae m(u)2 approximately equal to m(π)2/24, m(s)/m(u)=2m(k)F(k)/m(π)F(π)-1, leading to the numerical estimates m(u) approximately equal to 30MeV, m(s) approximately equal to 200MeV
Strangeness detection in ALICE experiment at LHC
Energy Technology Data Exchange (ETDEWEB)
Safarik, K. [European Lab. for Particle Physics, Geneva (Switzerland)
1995-07-15
The authors present some parameters of the ALICE detector which concern the detection of strange particles. The results of a simulation for neutral strange particles and cascades, together with estimated rates are presented. They also briefly discuss the detection of charged K-mesons. Finally, they mention the possibility of open charm particle detection.
Strange attractor simulated on a quantum computer
M. Terraneo; Georgeot, B.; D.L. Shepelyansky
2002-01-01
We show that dissipative classical dynamics converging to a strange attractor can be simulated on a quantum computer. Such quantum computations allow to investigate efficiently the small scale structure of strange attractors, yielding new information inaccessible to classical computers. This opens new possibilities for quantum simulations of various dissipative processes in nature.
Interpretation of strange hadron production at LHC
International Nuclear Information System (INIS)
We extend the SHM analysis of hadron production results showing here consistency with the increased experimental data set, stability of the fit with regard to inclusion of finite resonance widths and 2-star hyperon resonances. We present new results on strangeness yield as a function of centrality and present their interpretation in terms of QGP inspired model of strangeness abundance in the hadronizing fireball
Electromagnetic production of associated strangeness
International Nuclear Information System (INIS)
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.)
Weak Strangeness and Eta Production
Alam, M Rafi; Alvarez-Ruso, Luis; Simo, I Ruiz; Vacas, M J Vicente; Singh, S K
2013-01-01
We have studied strange particle production off nucleons through $\\Delta S =0 $ and $|\\Delta S| = 1$ channels, and specifically single kaon/antikaon, eta, associated particle production for neutrino/antineutrino induced processes as well as antineutrino induced single hyperon production processes. We have developed a microscopical model based on the SU(3) chiral Lagrangians. The basic parameters of the model are $f_\\pi$, the pion decay constant, Cabibbo angle, the proton and neutron magnetic moments and the axial vector coupling constants for the baryons octet. For antikaon production we have also included $\\Sigma^*(1385)$ resonance and for eta production $S_{11}(1535)$ and $S_{11}(1650)$ resonances are included.
Baryons as relativistic three-quark bound states
Eichmann, Gernot; Williams, Richard; Alkofer, Reinhard; Fischer, Christian S
2016-01-01
We review the spectrum and electromagnetic properties of baryons described as relativistic three-quark bound states within QCD. The composite nature of baryons results in a rich excitation spectrum, whilst leading to highly non-trivial structural properties explored by the coupling to external (electromagnetic and other) currents. Both present many unsolved problems despite decades of experimental and theoretical research. We discuss the progress in these fields from a theoretical perspective, focusing on nonperturbative QCD as encoded in the functional approach via Dyson-Schwinger and Bethe-Salpeter equations. We give a systematic overview as to how results are obtained in this framework and explain technical connections to lattice QCD. We also discuss the mutual relations to the quark model, which still serves as a reference to distinguish 'expected' from 'unexpected' physics. We confront recent results on the spectrum of non-strange and strange baryons, their form factors and the issues of two-photon proce...
Energy Technology Data Exchange (ETDEWEB)
Jardillier, Johann [Lab. de Physique Corpusculaire, Clermont-Ferrand-2 Univ., 63 - Aubiere (France)
1999-09-21
In the quark model, the proton is described as a system of three quarks UUD. However, recent experiments (CERN, SLAC) have shown that the strange quarks may contribute in a significant way to the mass and the spin of the proton. The HAPPEX experiment gives one further knowledge about the question of the role the strange quarks play inside the proton. It measures parity violating asymmetry in the scattering of polarized electrons from a proton because the latter is sensitive to the contribution of the strange quarks to the electromagnetic form factors of the nucleon. The observed asymmetry is in the order of a few ppm (part per million). The main difficulty of the experiment is to identify, to estimate and to minimize, as much as possible, all the systematic effects which could give rise to false asymmetries. This thesis discusses the principle of the HAPPEX experiment, its implementation at the Jefferson Lab (JLab), the processing and the analysis of the data, the systematic errors, and finally presents the result of the first data taking (1999) and its present interpretation. The HAPPEX experiment has measured, at Q{sup 2} = 0.5 (GeV/c){sup 2}, a strange quarks contribution of (1.0 {+-} 2.3)% to the electromagnetic form factors of the nucleon. The statistics and the systematic effects (measure of the electron beam polarization and knowledge of the neutron electric form factor) contribute equally to the error. (author)
Strangeness Production and Ultrarelativistic Cascades
Kahana, D E
1998-01-01
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 $\\sqrt{s}=17-20$. 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, including strange mesons, by separating the dynamics into two steps, a fast cascade involving only nucleons in the original colliding relativistic ions followed, after an appropriate delay, by 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. A byproduct, obtained here in preliminary calculations, is a description of str...
Strange particle production in heavy-ion collisions at the AGS
International Nuclear Information System (INIS)
The topic of strangeness production in relativistic heavy-ion collisions has been the subject of intense study due to the belief that the strange sector may be particularly sensitive to the QCD phase-transition in hot and/or dense hadronic matter. In particular, it has long been thought that strange-particle yields may be enhanced by quark-gluon plasma (QGP) formation though this open-quotes signatureclose quotes is significantly complicated by contributions from open-quotes ordinaryclose quotes hadronic processes. It has also been suggested that the restoration of chiral-symmetry in the QGP phase may significantly affect kaon production and the mass and/or width of the hidden open-quotes strangenessclose quotes φ meson. Experimental results from several experiments at the AGS will be presented, along with measurements of strange meson (K±,Ks) production, Λ, bar Λ, and Ξ production and φ production in 28Si+A and 197Au+A collisions. Recent measurements of the centrality dependence of the φ meson mass and width will be presented, along with measurements of low-pperpendiculars kaon production which show a remarkable enhancement that may result from modification of the kaon mass in the hot hadronic medium
Magnetized quark matter with a magnetic-field dependent coupling
Li, Chang-Feng; Wen, Xin-Jian; Peng, Guang-Xiong
2016-01-01
It was recently derived that the QCD running coupling is a function of the magnetic field strength under the strong magnetic field approximation. Inspired by this progress and based on the self-consistent solutions of gap equations, the properties of 2-flavor and 3-flavor quark matter are studied in the framework of the Nambu-Jona-Lasinio model with a magnetic-field dependent running coupling. We find that the dynamical quark masses as a function of the magnetic field strength is not monotonous in the fully chirally broken phase. Furthermore, the stability of magnetized quark matter with the running coupling is enhanced by lowering the free energy per baryon, which is expected to be more stable than that of the conventional coupling constant case. It is concluded that the magnetized strange quark matter described by running coupling can be absolutely stable.
Super-hypernuclei in the quark-shell model
International Nuclear Information System (INIS)
A super-hypernucleus is a nucleus which consists of many strange quarks as well as up and down quarks. An important part of the results of our recent investigation on the mass spectrum and other properties of super-hypernuclei in the quark-shell model is reported. It is expected that not only certain exotic nuclei such as the 'dideltas' (Dδ++++ and Dδ----). but also certain super-hypernuclei such as the 'hexalambda' (Hλ) and the 'vigintiquattuoralambda' (Vqλ) may appear as quasi-stable nuclei. However, in the quark-shell model, there is no qualitative reason why the 'dihyperon' or 'H dibaryon' (H) should be quasi-stable or even stable. Many other predictions including a sudden increase of the K/π ratio due to the production of super-hypernuclei in heavy-ion collisions at high energies are also made. (author)
Neutrino diffusive transport in hot quark matter: a detailed analysis
Colvero, Gustavo C
2014-01-01
We perform an extensive analysis of neutrino diffusion in quark matter within the MIT bag model at arbitrary temperature and degeneracy. We examine in detail the contribution of each of the relevant weak interaction processes to the total neutrino opacity and evaluate the effect of the strange quark mass, the bag constant, and the QCD perturbative corrections to the MIT bag model. We also investigate the anisotropic contribution to the neutrino distribution function in scatterings, the mean energy transfer and the mean scattering angle. The density and temperature dependence of the diffusion coefficients $D_n$ that govern the cooling and deleptonization of a compact star is shown in detail. Finally, our numerical results for the neutrino mean free paths are compared against known analytic approximations. We conclude that neutrino scattering constitutes a significant portion of the total neutrino opacity in leptonized quark matter and neutrino-quark scattering is, in general, very similar to neutrino-electron ...
Quark-cluster Stars: hints from the surface
Dai, Shi
2012-01-01
The matter inside pulsar-like compact stars could be in a quark-cluster phase since in cold dense matter at a few nuclear densities (2 to 10 times), quarks could be coupled still very strongly and condensate in position space to form quark clusters. Quark-cluster stars are chromatically confined and could initially be bare, therefore the surface properties of quark-cluster stars would be quite different from that of conventional neutron stars. Some facts indicate that a bare and self-confined surface of pulsar-like compact stars might be necessary in order to naturally understand different observational manifestations. On one hand, as for explaining the drifting sub-pulse phenomena, the binding energy of particles on pulsar surface should be high enough to produce vacuum gaps, which indicates that pulsar's surface might be strongly self-confined. On the other hand, a bare surface of quark-cluster star can overcome the baryon contamination problem of Gamma-ray burst as well as promote a successful core-collaps...
Massive Hybrid Stars with Strangeness
Takatsuka, Tatsuyuki; Masuda, Kota
2014-01-01
How massive the hybrid stars could be is discussed by a "3-window model" proposed from a new strategy to construct the equation of state with hadron-quark transition. It is found that hybrid stars have a strong potentiality to generate a large mass compatible with two-solar-mass neutron star observations.
Constraining Light-Quark Yukawa Couplings from Higgs Distributions
Bishara, Fady; Monni, Pier Francesco; Re, Emanuele
2016-01-01
We propose a novel strategy to constrain the bottom and charm Yukawa couplings by exploiting LHC measurements of transverse momentum distributions in Higgs production. Our method does not rely on the reconstruction of exclusive final states or heavy-flavour tagging. Compared to other proposals it leads to an enhanced sensitivity to the Yukawa couplings due to distortions of the differential Higgs spectra from emissions which either probe quark loops or are associated to quark-initiated production. We derive constraints using data from LHC Run I, and we explore the prospects of our method at future LHC runs. Finally, we comment on the possibility of bounding the strange Yukawa coupling.
Amsler, C.; DeGrand, T.; Krusche, B.
2008-01-01
This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2778 new measurements from 645 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and re...
On the conversion of neutron stars into quark stars
Pagliara, Giuseppe
2013-01-01
The possible existence of two families of compact stars, neutron stars and quark stars, naturally leads to a scenario in which a conversion process between the two stellar objects occurs with a consequent release of energy of the order of $10^{53}$ erg. We discuss recent hydrodynamical simulations of the burning process and neutrino diffusion simulations of cooling of a newly formed strange star. We also briefly discuss this scenario in connection with recent measurements of masses and radii of compact stars.
The Adler Function for Light Quarks in Analytic Perturbation Theory
Milton, K. A.; Solovtsov, I. L.; Solovtsova, O. P.
2001-01-01
The method of analytic perturbation theory, which avoids the problem of ghost-pole type singularities and gives a self-consistent description of both spacelike and timelike regions, is applied to describe the "light" Adler function corresponding to the non-strange vector channel of the inclusive decay of the $\\tau$ lepton. The role of threshold effects is investigated. The behavior of the quark-antiquark system near threshold is described by using a new relativistic resummation factor. It is ...
Chemical Evolution of Strongly Interacting Quark-Gluon Plasma
International Nuclear Information System (INIS)
At very initial stage of relativistic heavy ion collisions a wave of quark-gluon matter is produced from the break-up of the strong color electric field and then thermalizes at a short time scale (~1 fm/c). However, the quark-gluon plasma (QGP) system is far out of chemical equilibrium, especially for the heavy quarks which are supposed to reach chemical equilibrium much late. In this paper a continuing quark production picture for strongly interacting QGP system is derived, using the quark number susceptibilities and the equation of state; both of them are from the results calculated by the Wuppertal-Budapest lattice QCD collaboration. We find that the densities of light quarks increase by 75% from the temperature T=400 MeV to T=150 MeV, while the density of strange quark annihilates by 18% in the temperature region. We also offer a discussion on how this late production of quarks affects the final charge-charge correlations
Broken superfluid in dense quark matter
International Nuclear Information System (INIS)
Quark matter at high densities is a superfluid. Properties of the superfluid become highly non-trivial if the effects of strange-quark mass and the weak interactions are considered. These properties are relevant for a microscopic description of compact stars. We discuss the effect of a (small) explicitly symmetry-breaking term on the properties of a zero-temperature superfluid in a relativistic φ4 theory. If the U(1) symmetry is exact, chemical potential and superflow can be equivalently introduced either via (1) a background gauge field or (2) a topologically nontrivial mode. However, in the case of the explicitly broken symmetry, we demonstrate that the scenarios (1) and (2) lead to quantitatively different results for the mass of the pseudo-Goldstone mode and the critical velocity for superfluidity.
Shi, Shusu
2016-01-01
Strange hadrons, especially multi-strange hadrons are good probes for the early partonic stage of heavy ion collisions due to their small hadronic cross sections. In this paper, I give a brief review on the elliptic flow measurements of strange and multi-strange hadrons in relativistic heavy ion collisions at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC).
Chemical Freeze-out of Strange Particles and Possible Root of Strangeness Suppression
Bugaev, K A; Cleymans, J; Ivanytskyi, A I; Mishustin, I N; Nikonov, E G; Sagun, V V
2013-01-01
Two approaches to treat the chemical freeze-out of strange particles in hadron resonance gas model are analyzed. The first one employs their non-equillibration via the usual \\gamma_s factor and such a model describes the hadron multiplicities measured in nucleus-nucleus collisions at AGS, SPS and RHIC energies with \\chi^2/dof = 1.15. Surprisingly, at low energies we find not the strangeness suppression, but its enhancement. Also we suggest an alternative approach to treat the strange particle freeze-out separately, but with the full chemical equilibration. This approach is based on the conservation laws which allow us to connect the freeze-outs of strange and non-strange hadrons. Within the suggested approach the same set of hadron multiplicities can be described better than within the conventional approach with \\chi^2/dof = 1.06. Remarkably, the fully equilibrated approach describes the strange hyperons and antihyperons much better than the conventional one.
The (ν,ν'Nγ) reaction on 16O and the strangeness content of the nucleon
International Nuclear Information System (INIS)
Recently we have pointed out that photons with energies between 5 and 10 MeV, generated by the (ν,ν''pγ) and (ν,ν''nγ) reactions on 16O, constitute a signal which allows a unique identification of supernova νμ and ντ neutrinos in water Cerenkov detectors. It was also shown that the cross sections for neutrino-induced knockout of a nucleon via a neutral current reaction on nuclei are affected by the strange quark content of the nucleon. Hence strangeness in the nucleon could have an influence on the energy spectrum of the photons emitted in these processes, which is investigated in the following. (orig.)
New Precision Limit on the Strange Vector Form Factors of the Proton
Ahmed, Z; Aniol, K A; Armstrong, D S; Arrington, J; Baturin, P; Bellini, V; Benesch, J; Beminiwattha, R; Benmokhtar, F; Canan, M; Camsonne, A; Cates, G D; Chen, J -P; Chudakov, E; Cisbani, E; Dalton, M M; de Jager, C W; De Leo, R; Deconinck, W; Decowski, P; Deng, X; Deur, A; Dutta, C; Franklin, G B; Friend, M; Frullani, S; Garibaldi, F; Giusa, A; Glamazdin, A; Golge, S; Grimm, K; Hansen, O; Higinbotham, D W; Holmes, R; Holmstrom, T; Huang, J; Huang, M; Hyde, C E; Jen, C M; Jin, G; Jones, D; Kang, H; King, P; Kowalski, S; Kumar, K S; Lee, J H; LeRose, J J; Liyanage, N; Long, E; McNulty, D; Margaziotis, D; Meddi, F; Meekins, D G; Mercado, L; Meziani, Z -E; Michaels, R; Munoz-Camacho, C; Mihovilovic, M; Muangma, N; Myers, K E; Nanda, S; Narayan, A; Nelyubin, V; Nuruzzaman,; Oh, Y; Pan, K; Parno, D; Paschke, K D; Phillips, S K; Qian, X; Qiang, Y; Quinn, B; Rakhman, A; Reimer, P E; Rider, K; Riordan, S; Roche, J; Rubin, J; Russo, G; Saenboonruang, K; Saha, A; Sawatzky, B; Silwal, R; Sirca, S; Souder, P A; Sperduto, M; Subedi, R; Suleiman, R; Sulkosky, V; Sutera, C M; Tobias, W A; Urciuoli, G M; Waidyawansa, B; Wang, D; Wexler, J; Wilson, R; Wojtsekhowski, B; Zhan, X; Yan, X; Yao, H; Ye, L; Zhao, B; Zheng, X
2011-01-01
The parity-violating cross-section asymmetry in the elastic scattering of polarized electrons from unpolarized protons has been measured at a four-momentum transfer squared Q2 = 0.624 GeV and beam energy E =3.48 GeV to be A_PV = -23.80 +/- 0.78 (stat) +/- 0.36 (syst) parts per million. This result is consistent with zero contribution of strange quarks to the combination of electric and magnetic form factors G_E^s + 0.517 G_M^s = 0.003 +/- 0.010 (stat) +/- 0.004 (syst) +/- 0.009 (ff), where the third error is due to the limits of precision on the electromagnetic form factors and radiative corrections. With this measurement, the world data on strange contributions to nucleon form factors are seen to be consistent with zero and not more than a few percent of the proton form factors.
Neutral strange particle production in π+/K+p interactions at 250 GeV/c
International Nuclear Information System (INIS)
This thesis in which a detailed study of Kn inclusive production in K+p and π+p interactions at 250 GeV/c is presented, concentrates on neutral strange interaction products and draws some conclusions about the fate of the strange quark. In ch. 2 the experimental setup is described and in ch. 3 the series of computer programs that perform data reduction. Ch. 4 deals with the selectionn of events and neutral kaons. Also the calculations needed to correct for losses and background are described there. In ch. 5 inclusive and semi-inclusive distributions are presented and compared to data obtained in experiments at lower beam energy. In ch. 6 the data are compared with model predictions. In ch. 7 the main conclusions are summarized. (H.W.). 64 refs.; 39 refs.; 19 tabs
International Nuclear Information System (INIS)
The associated strangeness production in pp collisions was studied at bombarding energies of 2.3 and 2.7 GeV by detecting the outgoing K+ particles with a high resolution magnetic spectrometer at forward angles up to 23.5 laboratory angle. The kaons were separated from an immense background of protons and pions by a highly resolving TOF electronics in addition to vetoes from Cerenkov detectors utilizing either β differing Cerenkov light cones in lucite or different thresholds for light production in aerogel. The hyperon-nucleon missing mass spectra obtained show strong deviations from pure phase space which is ascribed to final state interactions of the pΛ and the NΣ systems. The structures found are discussed and compared with results from K-d → π-YN experiments, with theoretical calculations in the frame of OBE models, and with the prediction of sharp strange dibaryon resonances from several quark-bag models. (orig.)
Properties of quark matter in a new quasiparticle model with QCD running coupling
Lu, ZhenYan; Peng, GuangXiong; Xu, JianFeng; Zhang, ShiPeng
2016-06-01
The running of the QCD coupling in the effective mass causes thermodynamic inconsistency problem in the conventional quasiparticle model. We provide a novel treatment which removes the inconsistency by an effective bag constant. The chemical potential dependence of the renormalization subtraction point is constrained by the Cauchy condition in the chemical potential space. The stability and microscopic properties of strange quark matter are then studied within the completely self-consistent quasiparticle model, and the obtained equation of state of quark matter is applied to the investigation of strange stars. It is found that our improved model can describe well compact stars with mass about two times the solar mass, which indicates that such massive compact stars could be strange stars.
Repulsive Vector Interaction in Three Flavor Magnetized Quark and Stellar Matter
Menezes, Débora P; Castro, Luis B; Costa, Pedro; Providência, Constan\\cca
2014-01-01
The effect of the vector interaction on three flavor magnetized matter is studied within the SU(3) Nambu--Jona-Lasiono quark model. We have considered cold matter under a static external magnetic field within two different models for the vector interaction in order to investigate how the form of the vector interaction and the intensity of the magnetic field affect the equation of state as well as the strangeness content. It was shown that the flavor independent vector interaction predicts a smaller strangeness content and, therefore, harder equations of state. On the other hand, the flavor dependent vector interaction favors larger strangeness content the larger the vector coupling. We have confirmed that at low densities the magnetic field and the vector interaction have opposite competing effects: the first one softens the equation of state while the second hardens it. Quark stars and hybrid stars subject to an external magnetic field were also studied. Larger star masses are obtained for the flavor indepen...
Discriminating hadronic and quark stars through gravitational waves of fluid pulsation modes
Flores, C V
2013-01-01
We investigate non-radial oscillations of hadronic, hybrid and pure self-bound strange quark stars with maximum masses above the mass of the recently observed massive pulsars PSR J1614-2230 and PSR J0348-0432 with $M \\approx 2 M_{\\odot}$. For the hadronic equation of state we employ different parametrizations of a relativistic mean-field model and for quark matter we use the MIT bag model including the effect of strong interactions and color superconductivity. We find that the first pressure mode for strange quark stars has a very different shape than for hadronic and hybrid stars. For strange quarks stars the frequency of the p1 mode is larger than 6 kHz and diverge at small stellar masses, but for hadronic and hybrid stars it is in the range 4-6 kHz. This allows an observational identification of strange stars even if extra information such as the mass, the radius or the gravitational redshift of the object is unavailable or uncertain. Also, we find as in previous works that the frequency of the g-mode asso...
Strange attractors in rattleback dynamics
Energy Technology Data Exchange (ETDEWEB)
Borisov, Aleksei V; Mamaev, Ivan S [Institute of Computer Science, Izhevsk (Russian Federation)
2003-04-30
This review is dedicated to the dynamics of the rattleback, a phenomenon with curious physical properties that is studied in nonholonomic mechanics. All known analytical results are collected here, and some results of our numerical simulation are presented. In particular, three-dimensional Poincare maps associated with dynamical systems are systematically investigated for the first time. It is shown that the loss of stability of periodic and quasiperiodic solutions, which gives rise to strange attractors, is typical of the three-dimensional maps related to rattleback dynamics. This explains some newly discovered properties of the rattleback related to the transition from regular to chaotic solutions at certain values of the physical parameters. (methodological notes)
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.
Ultrarelativistic cascades and strangeness production
International Nuclear Information System (INIS)
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.)
Ultrarelativistic cascades and strangeness production
Energy Technology Data Exchange (ETDEWEB)
Kahana, D.E. [State Univ. of New York, Stony Brook, NY (United States). Physics Dept.; Kahana, S.H. [Brookhaven National Lab., Upton, NY (United States). Physics Dept.
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.
Chaos, turbulence and strange attractors
International Nuclear Information System (INIS)
Using the turbulence example, the author recalls the two different conceptions of the nature of an erratic regime: the one in which a great number of elementary events are concerned (Landau) and the other one in which, on the contrary, a few number of elementary events are concerned (Ruelle and Takens). The last type of erratic comportment has a deterministic origin and is pointed by the adjective chaotic. Phase space for a dynamic system is presented and so the attractor nation. Chaos and notion of sensitiveness to initial conditions are defined. In scrutining the geometry of an attractor corresponding to a chaotic regime, the notion of strange attractor is shown. Some experiments results are given as illustration. Application field is recalled: for example, studies on hamiltonian chaos are made at DRFC (Department of research on controlled fusion at CEA) in relation with plasma instabilities
Potential description of charmonium and charmed-strange mesons from lattice QCD
Kawanai, Taichi
2015-01-01
We present spin-independent and spin-spin interquark potentials for the charmonium and charmed-strange mesons, which are calculated in 2+1 flavor lattice QCD simulations using the PACS-CS gauge configurations generated at the lightest pion mass ($M_\\pi \\approx 156(7)$~MeV) with a lattice cutoff of $a^{-1}\\approx 2.2$ GeV and a spatial volume of $(3~{\\rm fm})^3$. For the charm quark, we use a relativistic heavy quark (RHQ) action with fine tuned RHQ parameters, which closely reproduce both the experimental spin-averaged mass and hyper-fine splitting of the $1S$ charmonium. The interquark potential and the quark kinetic mass, both of which are key ingredients within the potential description of heavy-heavy and heavy-light mesons, are determined from the equal-time Bethe-Salpeter (BS) amplitude. The charmonium potentials are obtained from the BS wave function of $1S$ charmonia ($\\eta_c$ and $J/\\psi$ mesons), while the charmed-strange potential are calculated from the $D_s$ and $D_s^{\\ast}$ heavy-light mesons. We...
Decaying hadrons within constituent-quark models
Kleinhappel, Regina
2012-01-01
Within conventional constituent-quark models hadrons come out as stable bound states of the valence (anti)quarks. Thereby the resonance character of hadronic excitations is completely ignored. A more realistic description of hadron spectra can be achieved by including explicit mesonic degrees of freedom, which couple directly to the constituent quarks. We will present a coupled-channel formalism that describes such hybrid systems in a relativistically invariant way and allows for the decay of excited hadrons. The formalism is based on the point-form of relativistic quantum mechanics. If the confining forces between the (anti)quarks are described by instantaneous interactions it can be formally shown that the mass-eigenvalue problem for a system that consists of dynamical (anti)quarks and mesons reduces to a hadronic eigenvalue problem in which the eigenstates of the pure confinement problem (bare hadrons) are coupled via meson loops. The only point where the quark substructure enters are form factors at the m...
Mountain building of solid quark stars
Yang, Haifeng
2011-01-01
One of the key differences between normal neutron and (bare) quark stars is relevant to the fact that the former are gravitationally bound while the latter self-confined unless their masses approach the maximum mass. This difference results in the possibility that quark stars could be very low massive whereas neutron stars cannot. Mountains could also be build on quark stars if realistic cold quark matter is in a solid state, and an alternative estimation of the mountain building is present. As spinning compact objects with non-axisymmetric mass distribution will radiate gravitational waves, the equations of states of pulsars could be constraint by the amplitude of gravitational waves being dependent on the heights of mountains. We then estimate the maximum mountains and thus quadrupole moment on solid quark stars, to be consistent with that by Owen (2005) if the breaking strain is 0.1, addressing that a solid quark star with mass < 10^{-2} Msun could be `potato-like'. We estimate the gravitational wave am...
Very Late Bare Metal Stent Thrombosis
Directory of Open Access Journals (Sweden)
Mariana Soto Herrera
2013-01-01
Full Text Available Very late stent thrombosis is a rare and not-well-understood complication after bare metal stent implantation. It usually presents as an ST elevation acute coronary syndrome and it is associated with high rates of morbidity and mortality. Pathophysiologic mechanisms are not well defined; nevertheless, recent studies have proposed a neoatherosclerotic process as the triggering mechanism. We present the case of a patient with bare metal very late stent thrombosis 12 years after implantation.
Very Late Bare Metal Stent Thrombosis
Soto Herrera, Mariana; Restrepo, José A.; Felipe Buitrago, Andrés; Gómez Mejía, Mabel; Díaz, Jesús H.
2013-01-01
Very late stent thrombosis is a rare and not-well-understood complication after bare metal stent implantation. It usually presents as an ST elevation acute coronary syndrome and it is associated with high rates of morbidity and mortality. Pathophysiologic mechanisms are not well defined; nevertheless, recent studies have proposed a neoatherosclerotic process as the triggering mechanism. We present the case of a patient with bare metal very late stent thrombosis 12 years after implantation. PMID:24829831
Strange particle production from SIS to LHC
Indian Academy of Sciences (India)
H Oeschler; J Cleymans; K Redlich
2003-05-01
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, e.g. the different centrality dependences of pions and kaons. Furthermore, the independence of the + to - ratio on the number of participating nucleons observed between SIS and relativistic heavy-ion collider (RHIC) is consistent with this model. The observed maximum in the +/+ excitation function is also seen in the ratio of strange to non-strange particle production. The appearance of this maximum around 30 A$\\cdot$GeV is due to the energy dependence of the chemical freeze-out parameters and .
Search for non-strange dibaryons
Indian Academy of Sciences (India)
Arun K Jain
2006-05-01
Inspite of tremendous interest there has been sporadic searches for dibaryon resonances in the past few decades. The main hurdle one faces in this search is their identification, their signature and practically no guide to their location. With the identification of the pentaquark-+ resonance one is encouraged to look for the discovery of strange dibaryons also. However where and how to look for non-strange dibaryons is not clear. The transition from a bipolar to a unipolar non-strange dibaryon may possibly be seen in the (, 2) reactions on heavy nuclei. The change of the finite size of the $p-p$ interaction vertex can be identified as a sudden change in the extracted DWIA spectroscopic factor. The DWIA anomalies are to be searched for in the existing (, 2) reaction data for the identification of non-strange dibaryons.
Origin of isotopic spin and strangeness
International Nuclear Information System (INIS)
An explanation of the origin of isotopic spin is given by applying the theory and calculations in the author's previous papers. An explanation of the origin of strangeness and broken SU3 is given as well
Associated strangeness production at intermediate energies
International Nuclear Information System (INIS)
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)
The strange asymmetry of the proton sea
International Nuclear Information System (INIS)
We present a phenomenologically motivated parameterization of the s and s-bar parton distribution functions in the proton, calculated in the framework of the Meson Cloud Model. Parameters of the model have been fixed by comparing to a recent parameterization of the strange asymmetry of the proton sea, which has emerged from a global fit to Deep Inelastic Scattering data. The model reproduces quite well the the asymmetry of the strange sea of the proton.
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.
Small quark stars in the chromodielectric model
Malheiro, M; Nuss, L G; Fiolhais, M; Taurines, A R
2001-01-01
The Chromodielectric Model with a quartic potential is used to describe homogeneous strange quark matter, in beta equilibrium, at high densities. Two equations of state (EOS) are obtained for the same set of model parameters: one corresponds to a chiral restored phase with almost massless quarks and no electrons, and the other to a chiral broken phase. Depending on the model parameters, a phase transition between the two phases may occur. With those EOS the structure of compact stars is investigated and two types of stars are obtained: larger ones with radius $R\\sim 10 - 12$ km, a hadron mantle and a mass $M\\sim 1- 2 M_\\odot$, and smaller pure quark stars, in a chiral restored phase, with $R\\sim 5 - 8$ km, $M\\sim M_\\odot$ and a large baryon density at the edge. The phenomenology of the compact object RX J185635-3754, whose best fit for the radius and mass is $R\\sim 6$ km and $M\\sim 0.9 M_\\odot$, lies in the class of small quark stars predicted by the chromodielectric model.
Miyatsu, Tsuyoshi; Cheoun, Myung-Ki; Saito, Koichi
2015-11-01
We construct the equation of state (EoS) for neutron stars explicitly including hyperons and quarks. Using the quark-meson coupling model with the relativistic Hartree-Fock approximation, the EoS for hadronic matter is derived by taking into account the strange (σ* and ϕ) mesons as well as the light non-strange (σ, ω, {\\boldsymbol{π }}, and {\\boldsymbol{ρ }}) mesons. Relevant coupling constants are determined to reproduce the experimental data of nuclear matter and hypernuclei in SU(3) flavor symmetry. For quark matter, we employ the MIT bag model with a one-gluon-exchange interaction, and Gibbs criteria for chemical equilibrium in the phase transition from hadrons to quarks. We find that the strange vector (ϕ) meson and the Fock contribution make the hadronic EoS stiff, and that the maximum mass of a neutron star can be consistent with the observed mass of heavy neutron stars even if the coexistence of hadrons and quarks takes place in the core. However, in the present calculation, the transition to pure quark matter does not occur in stable neutron stars. Furthermore, the lower bound of the critical chemical potential of the quark-hadron transition at zero temperature turns out to be around 1.5 GeV in order to be consistent with the recent observed neutron-star data.
International Nuclear Information System (INIS)
The predictions are made for relative yields kaons, hyperons, antinucleons, and lightest sub(ΛΛ)sup(4)He, sub(ΛΛ)sup(6)He and sub(ΛΛ)sup(10)B hyperfragments for various combinations of colliding nuclei up to 10 GeV/nucleon within the firestreak model taking account of the associated nature of the strange particle production. These results may be used to identify the signs of a possible phase transition of hadrons into the quark-gluon plasma
Strange and charmed baryons using N{sub f}=2 twisted mass QCD
Energy Technology Data Exchange (ETDEWEB)
Papinutto, Mauro; Carbonell, Jaume [UJF, CNRS/IN2P, INPG (France). Lab. de Physique Subatomique et de Cosmologie; Drach, Vincent [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Alexandrou, Constantia [Cyprus Univ., Nicosia (Cyprus). Dept. of Physics
2010-12-15
We compute the mass spectrum for strange/charmed baryons in the partially quenched approach using N{sub f}=2 twisted mass QCD configurations. We investigate two main issues: the size of lattice artefacts using three values of the lattice spacing (the smallest of which is approximately 0.05 fm) and the dependence of baryon masses on meson (or quark) masses. We thus perform a global fit in order to extrapolate simultaneously to the continuum limit and to the physical point. We estimate the masses of {omega}{sub sss}, {xi}{sub dss}, {lambda}{sub uds}, {omega}{sub ccc}, {xi}{sub dcc}, {lambda}{sub udc}. (orig.)
Distinguishing Newly Born Strange Stars from Neutron Stars with g-Mode Oscillations
International Nuclear Information System (INIS)
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
Coupled channel approach to strangeness S = -2 baryon-bayron interactions in Lattice QCD
Sasaki, Kenji; Doi, Takumi; Hatsuda, Tetsuo; Ikeda, Yoichi; Inoue, Takashi; Ishii, Noriyoshi; Murano, Keiko
2015-01-01
The baryon-baryon interactions with strangeness S = -2 with the flavor SU(3) breaking are calculated for the first time by using the HAL QCD method extended to coupled channel system in lattice QCD. The potential matrices are extracted from the Nambu-Bethe-Salpeter wave functions obtained by the 2+1 flavor gauge configurations of CP-PACS/JLQCD Collaborations with a physical volume of 1.93 fm cubed and with m_pi/m_K = 0.96, 0.90, 0.86. The spatial structure and the quark mass dependence of the potential matrix in the baryon basis and in the SU(3) basis are investigated.
The energy density representation of the strangeness enhancement from p+p to Pb+Pb
Cuautle, E
2016-01-01
The energy density is the prime parameter to define the deconfinement of quarks and gluons occurring in collisions of heavy ions. Recently, there is mounting evidence that many observables in proton-proton collisions behave in a manner very similar to the one observed in heavy ions. We present as an additional piece of evidence, a scaling of the strange particle yields as a function of the energy density of the three collision systems: p+p p+Pb and Pb+Pb, using the latest results of the ALICE collaboration.
Electromagnetic properties of baryons in the constituent quark model
International Nuclear Information System (INIS)
The electromagnetic properties of baryons are investigated in the framework of a relativized quark model. The model includes beyond the usual single quark transition ansatz relativistic effects due to the strong interaction and confinement forces between the quarks. Furthermore the center-of-mass motion of the three-quark system is separated off in a Lorentz-invariant way. All relativistic correction terms are obtained by expanding the corresponding relativistic expressions in powers of the quark velocity. In this way recoil effects on the electromagnetic interaction between the photon and the baryon could be explicitly studied. Using the harmonic oscillator wavefunctions with the configuration mixing from the Isgur-Karl model, the form factors of the nucleon and the electromagnetic transition amplitudes both for longitudinally and transversely polarized photons are calculated for the most important baryon resonances. An extension to baryons involving strange quarks is also considered. Comparisons are made with the results of the nonrelativistic quark model and with some other approaches. (orig.)
J/ψ→γBB Decays and the Quark-pair Creation Model
Institute of Scientific and Technical Information of China (English)
平荣刚; 姜焕清; 沈彭年; 邹冰松
2002-01-01
We generalize the quark-pair creation model to a study of the radiative decays J/ψ→γBB by assuming that the u, d, or s quark pairs are created with the same interaction strength. From the calculation of the ratio of the decay widths Γ(J/ ψ→γpp)/Γ(J/ ψ→ pp), we extract the quark-pair creation strength gI = 15.40 GeV. Based on the SU (6) spin-flavour basis and the "uds" basis, the radiative decay branching ratios containing strange baryons are evaluated. Measurements for these decay widths from the BESII data are suggested.
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.
Shock wave produced by hadron-quark phase transition in neutron star
International Nuclear Information System (INIS)
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
Miyatsu, Tsuyoshi; Saito, Koichi
2015-01-01
We construct the equation of state (EoS) for neutron stars explicitly including hyperons and quarks. Using the quark-meson coupling model with relativistic Hartree-Fock approximation, the EoS for hadronic matter is derived by taking into account the strange ($\\sigma^{\\ast}$ and $\\phi$) mesons as well as the light non-strange ($\\sigma$, $\\omega$, $\\vec{\\pi}$ and $\\vec{\\rho}$) mesons. Relevant coupling constants are determined to reproduce the experimental data of nuclear matter and hypernuclei in SU(3) flavor symmetry. For quark matter, we employ the MIT bag model with one-gluon-exchange interaction, and Gibbs criteria for chemical equilibrium in the phase transition from hadrons to quarks. We find that the strange vector ($\\phi$) meson and the Fock contribution make the hadronic EoS stiff, and that the maximum mass of a neutron star can be consistent with the observed mass of heavy neutron stars even if the coexistence of hadrons and quarks takes place in the core. However, in the present calculation the tran...
Charge balance functions in a scenario of continuing charge production in quark matter
Pan, Ying-Hua; Zhang, Wei-Ning
2015-11-01
We study the charge balance functions of π+π- and K+K- in a scenario of continuing charge creation in a strongly interacting quark-gluon plasma (QGP) in high-energy heavy-ion collisions, using relativistic hydrodynamics and the lattice QCD results of quark susceptibilities and the equation of state of the QGP. We find that the charge balance functions are dominated by their QGP components because most charges are produced before the hadronic stage. The hadronic component of the balance function of π+π- is small but non-negligible. The balance function of K+K- has a negative hadronic component because the strangeness decreases during the system evolution. The correlation between light and strange quarks leads to small enhancements of the balance functions at small rapidity difference.
Charge balance functions in a scenario of continuing charge production in quark matter
Energy Technology Data Exchange (ETDEWEB)
Pan, Ying-Hua [Harbin Institute of Technology, Department of Physics, Heilongjiang (China); Zhang, Wei-Ning [Harbin Institute of Technology, Department of Physics, Heilongjiang (China); Dalian University of Technology, School of Physics and Optoelectronic Technology, Liaoning (China)
2015-11-15
We study the charge balance functions of π{sup +}π{sup -} and K{sup +}K{sup -} in a scenario of continuing charge creation in a strongly interacting quark-gluon plasma (QGP) in high-energy heavy-ion collisions, using relativistic hydrodynamics and the lattice QCD results of quark susceptibilities and the equation of state of the QGP. We find that the charge balance functions are dominated by their QGP components because most charges are produced before the hadronic stage. The hadronic component of the balance function of π{sup +}π{sup -} is small but non-negligible. The balance function of K{sup +}K{sup -} has a negative hadronic component because the strangeness decreases during the system evolution. The correlation between light and strange quarks leads to small enhancements of the balance functions at small rapidity difference. (orig.)
Charge balance functions in a scenario of continuing charge production in quark matter
International Nuclear Information System (INIS)
We study the charge balance functions of π+π- and K+K- in a scenario of continuing charge creation in a strongly interacting quark-gluon plasma (QGP) in high-energy heavy-ion collisions, using relativistic hydrodynamics and the lattice QCD results of quark susceptibilities and the equation of state of the QGP. We find that the charge balance functions are dominated by their QGP components because most charges are produced before the hadronic stage. The hadronic component of the balance function of π+π- is small but non-negligible. The balance function of K+K- has a negative hadronic component because the strangeness decreases during the system evolution. The correlation between light and strange quarks leads to small enhancements of the balance functions at small rapidity difference. (orig.)
Direct Evaluation of the Quark Content of Nucleons from Lattice QCD at the Physical Point
Abdel-Rehim, A.; Alexandrou, C.; Constantinou, M.; Hadjiyiannakou, K.; Jansen, K.; Kallidonis, Ch.; Koutsou, G.; Avilés-Casco, A. Vaquero
2016-06-01
We evaluate the light, strange, and charm scalar content of the nucleon using one lattice QCD ensemble generated with two degenerate light quarks with mass fixed to their physical value. We use improved techniques to evaluate the disconnected quark loops to sufficient accuracy to determine the strange and charm nucleon σ terms in addition to the light quark content σπ N. We find σπ N=37.2 (2.6 )(4.7 2.9 ) MeV , σs=41.1 (8.2 )(7.8 5.8 ) MeV , and σc=79 (21 )(12 8 ) MeV , where the first error is statistical and the second is the systematic error due to the determination of the lattice spacing, the assessment of finite volume, and residual excited state effects.
Direct Evaluation of the Quark Content of Nucleons from Lattice QCD at the Physical Point.
Abdel-Rehim, A; Alexandrou, C; Constantinou, M; Hadjiyiannakou, K; Jansen, K; Kallidonis, Ch; Koutsou, G; Avilés-Casco, A Vaquero
2016-06-24
We evaluate the light, strange, and charm scalar content of the nucleon using one lattice QCD ensemble generated with two degenerate light quarks with mass fixed to their physical value. We use improved techniques to evaluate the disconnected quark loops to sufficient accuracy to determine the strange and charm nucleon σ terms in addition to the light quark content σ_{πN}. We find σ_{πN}=37.2(2.6)(4.7/2.9) MeV, σ_{s}=41.1(8.2)(7.8/5.8) MeV, and σ_{c}=79(21)(12/8) MeV, where the first error is statistical and the second is the systematic error due to the determination of the lattice spacing, the assessment of finite volume, and residual excited state effects. PMID:27391717
On K→ππ amplitudes with a light charm quark
International Nuclear Information System (INIS)
We compute the leading-order low-energy constants of the ΔS=1 effective weak Hamiltonian in the quenched approximation of QCD with up, down, strange, and charm quarks degenerate and light (GIM limit). The low-energy constants are extracted by comparing the predictions of finite volume chiral perturbation theory with lattice QCD computations of suitable correlation functions carried out with quark masses ranging from a few MeV up to half of the physical strange mass. We observe a large ΔI=1/2 enhancement in this corner of the parameter space of the theory. Although matching with the experimental result is not observed for the ΔI=1/2 amplitude, our computation suggests large QCD contributions to the physical ΔI=1/2 rule in the GIM limit, and represents the first step to quantify the role of the charm quark-mass in K→ππ amplitudes. (Orig.)
Thermodynamics of Constituent Quarks
Pirner, H. J.; Wachs, M
1997-01-01
We investigate the thermal behavior of quarks and antiquarks interacting via a temperature-dependent linear potential. The quarks are constituent quarks with dynamically generated masses from the background linear $\\sigma$-model.We find a transition from a system of bound mesons to a correlated quark gas at the same temperature as the chiral transition temperature.
Rodionov, E. N.
1994-01-01
We build a model which is based on the assumption that the {\\bf c} and {\\bf s,b} quarks are excited states of {\\bf u} and {\\bf d} quarks. This model predicts the non-existence of the {\\bf top} quark and estimates the size of the quarks to be of order $10^{-7}$ fm.
Strange particle production in proton–proton collisions at √s = 0.9 TeV with ALICE at the LHC
Aamodt, K.; Abrahantes Quintana, A.; D. Thomas; van Leeuwen, M.(Institute for Subatomic Physics of Utrecht University, Utrecht, Netherlands); M. Verweij; Zynovyev, M.
2011-01-01
The production of mesons containing strange quarks (K0s, phi) and both singly and doubly strange baryons (Lambda, Anti-Lambda, and Xi+Anti-Xi) are measured at central rapidity in pp collisions at $\\sqrt{s}$ = 0.9 TeV with the ALICE experiment at the LHC. The results are obtained from the analysis of about 250 k minimum bias events recorded in 2009. Measurements of yields (dN/dy) and transverse momentum spectra at central rapidities for inelastic pp collisions are presented. For mesons, we rep...
Theoretical perspectives on strange physics
International Nuclear Information System (INIS)
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, K0-anti K0 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
Theoretical perspectives on strange physics
Energy Technology Data Exchange (ETDEWEB)
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/sup 0/-anti K/sup 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, ..mu.. decays, hyperon decays and neutrino physics is given. (WHK)
Quark masses and strong coupling constant in 2+1 flavor QCD
Maezawa, Y
2016-01-01
We present a determination of the strange, charm and bottom quark masses as well as the strong coupling constant in 2+1-flavor lattice QCD simulations using Highly Improved Staggered Quark action. The ratios of the charm quark mass to the strange quark mass and the bottom quark mass to the charm quark mass are obtained from the meson masses calculated on the lattice and found to be $m_c/m_s=11.871(91)$ and $m_b/m_c=4.528(57)$ in the continuum limit. We also determine the strong coupling constant and the charm quark mass using the moments of pseudoscalar charmonium correlators: $\\alpha_s(\\mu=m_c)=0.3697(75)$ and $m_c(\\mu=m_c)=1.267(11)$ GeV. Our result for $\\alpha_s$ corresponds to the determination of the strong coupling constant at the lowest energy scale so far and is translated to the value $\\alpha_s(\\mu=M_Z,n_f=5)=0.11622(75)$.
Scaling studies of QCD with the dynamical highly improved staggered quark action
International Nuclear Information System (INIS)
We study the lattice spacing dependence, or scaling, of physical quantities using the highly improved staggered quark (HISQ) action introduced by the HPQCD/UKQCD Collaboration, comparing our results to similar simulations with the asqtad fermion action. Results are based on calculations with lattice spacings approximately 0.15, 0.12, and 0.09 fm, using four flavors of dynamical HISQ quarks. The strange and charm quark masses are near their physical values, and the light-quark mass is set to 0.2 times the strange-quark mass. We look at the lattice spacing dependence of hadron masses, pseudoscalar meson decay constants, and the topological susceptibility. In addition to the commonly used determination of the lattice spacing through the static quark potential, we examine a determination proposed by the HPQCD Collaboration that uses the decay constant of a fictitious ''unmixed ss'' pseudoscalar meson. We find that the lattice artifacts in the HISQ simulations are much smaller than those in the asqtad simulations at the same lattice spacings and quark masses.
On the anomalous mass defect of strange stars in the Field Correlator Method
Pereira, F. I. M.
2016-09-01
We investigate general aspects of the mass defects of strange stars in the context of the Field Correlator Method, without magnetic field. The main parameters of the model that enter the corresponding nonperturbative equation of state of the quark gluon plasma are the gluon condensate G2 and the large distance static Q Q bar potential V1. We calculate mass defects of stellar configurations in the central density range 11 mass defects are strongly dependent on the model parameters. For a large range of values of G2 and V1, we obtain anomalous mass defects with magnitudes around 1053 erg, of the same order of the observed energies of gamma-ray bursts and neutrino emissions in SN1987A, and of the theoretically predicted energies of the quark-novae explosions.
QCD sum rule study of a charged bottom-strange scalar meson
Zanetti, C. M.; Nielsen, M.; Khemchandani, K. P.
2016-05-01
Using the QCD sum rule approach, we investigate the possible four-quark structure for the new observed Bs0π± narrow structure (D0). We use a diquak-antidiquark scalar current and work to the order of ms in full QCD, without relying on 1 /mQ expansion. Our study indicates that although it is possible to obtain a stable mass in agreement with the state found by the D0 collaboration, more constraint analysis (simultaneous requirement of the OPE convergence and the dominance of the pole on the phenomenological side) leads to a higher mass. We also predict the masses of the bottom scalar tetraquark resonances with zero and two strange quarks.
Narrow baryonia with open hidden strangeness
International Nuclear Information System (INIS)
A search for baryonia with open and hidden strangeness decaying into strange particles has been carried out in a neutron beam with a mean momentum of 40 GeV/c with the BIS-2 spectrometer at the Serpukhov accelerator. There is a strong indication of the existence of baryonia with negative (Ms) and positive (M-bars) strangeness, decaying respectively into Λp-bar + pions and Λ-barp + pions. The isotopic spin of the strange baryonia is ≥ 3/2. Their mean mass is (3060 ±5 (st.) ± 20 (syst.)) MeV/c2. There is an indication of the existence of narrow baryonium with hidden strangeness (Mφ), decaying into Λp-barK+(+π±), Λ-barpK-(+π±) and K0spp-barK±. The mean value of its mass is (3260 ±5 (st.) ±20 (syst.)) MeV/c2. The widths of the searched baryonia are (35 ± 5) MeV/c. The production cross-sections the baryonia in the kinematic region XF ≥0.2 and Pt ≤ 1 GeV/c, are (0.3 - 1.0) μb/per nucleon (90% C.L.). 33 refs.; 9 figs.; 4 tabs
Strange hadron production at low transverse momenta
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.
Bound States of (Anti-)Scalar-Quarks in $SU(3)_{c}$ Lattice QCD
Iida, H; Takahashi, T T
2007-01-01
Light scalar-quarks \\phi (colored scalar particles or idealized diquarks) and their color-singlet hadronic states are studied with quenched SU(3)_c lattice QCD in terms of mass generation. We investigate ``scalar-quark mesons'' \\phi^\\dagger \\phi and ``scalar-quark baryons'' \\phi\\phi\\phi as the bound states of scalar-quarks \\phi. We also investigate the bound states of scalar-quarks \\phi and quarks \\psi, i.e., \\phi^\\dagger \\psi, \\psi\\psi\\phi and \\phi\\phi\\psi, which we name ``chimera hadrons''. All the new-type hadrons including \\phi are found to have a large mass due to large quantum corrections by gluons, even for zero bare scalar-quark mass m_\\phi=0 at a^{-1}\\sim 1{\\rm GeV}. We conjecture that all colored particles generally acquire a large effective mass due to dressed gluon effects.
International Nuclear Information System (INIS)
Starting in 2001, the MILC Collaboration began a large scale calculation of heavy-light meson decay constants using clover valence quarks on esembles of three flavor configurations. For the coarse configurations, with a=0.12 fm, eight combinations of dynamical light and strange quarks have been analyzed. For the fine configurations, with a=0.09 fm, three combinations of quark masses are studied. Since we last reported on this calculation, statistics have been increased on the fine ensembles, and, more importantly, a preliminary value fir the perturbative renormalization of the axial-vector current has become available. Thus, results for fB, fBs, fD and fDs can, in principle, be calculated in MeV, in addition to decay-constant ratios that were calculated previously
Bernard, C; DeTar, C; Gottlieb, S; Gregory, E B; Heller, U M; Osborn, J; Sugar, R L; Toussaint, D; Gottlieb, Steven
2005-01-01
Starting in 2001, the MILC Collaboration began a large scale calculation of heavy-light meson decay constants using clover valence quarks on ensembles of three flavor configurations. For the coarse configurations, with a=0.12 fm, eight combinations of dynamical light and strange quarks have been analyzed. For the fine configurations, with a=0.09 fm, three combinations of quark masses are studied. Since we last reported on this calculation, statistics have been increased on the fine ensembles, and, more importantly, a preliminary value for the perturbative renormalization of the axial-vector current has become available. Thus, results for f_B, f_{B_s}, f_D and f_{D_s} can, in principle, be calculated in MeV, in addition to decay-constant ratios that were calculated previously.
Bare nominals and reference to capacities
Swart, Henriëtte de; Winter, Y.; Zwarts, J.
2007-01-01
Prefinal version. This paper concentrates on the syntax and semantics of bare nominals in Germanic and Romance languages. These languages do not normally allow nominals to occur without an article. However, some syntactic configurations, including predicative constructions, supplementives and some p
(Strange) meson interferometry at RHIC
International Nuclear Information System (INIS)
We make predictions for the kaon interferometry measurements in Au+Au collisions at the relativistic heavy ion collider (RHIC). A first-order phase transition from a thermalized quark-gluon plasma (QGP) to a gas of hadrons is assumed for the transport calculations. The fraction of kaons that are directly emitted from the phase boundary is considerably enhanced at large transverse momenta KT ∼ 1 GeV/c. In this kinematic region, the sensitivity of the Rout/Rside ratio to the QGP properties is enlarged. The results of the one-dimensional correlation analysis are presented. The extracted interferometry radii, depending on KT, are not unusually large and are strongly affected by finite momentum resolution effects. (author)
Chemical Evolution of Strongly Magnetized Quark Core in a Newborn Neutron Star
Ghosh, T K; Ghosh, Tanusri; Chakrabarty, Somenath
2001-01-01
The chemical evolution of nascent quark matter core in a newborn compact neutron star is studied in presence of a strong magnetic field. The effective rate of strange quark production in degenerate quark matter core in presence of strong magnetic fields is obtained. The investigations show that in presence of strong magnetic fields a quark matter core becomes energetically unstable and hence a deconfinement transition to quark matter at the centre of a compact neutron star under such circumstances is not possible. The critical strength of magnetic field at the central core to make the system energetically unstable with respect to dense nuclear matter is found to be $\\sim 4.4\\times 10^{13}$G. This is the typical strength at which the Landau levels for electrons are populated. The other possible phase transitions at such high density and ultra strong magnetic field environment are discussed.
A new deterministic model of strange stars
International Nuclear Information System (INIS)
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.)
A new deterministic model of strange stars
Rahaman, Farook; Kuhfittig, P K F; Shit, G C; Rahman, Mosiur
2014-01-01
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.
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.)
Strange and charm mesons at FAIR
Tolos, L; Gamermann, D; Garcia-Recio, C; Molina, R; Nieves, J; Oset, E; Ramos, A
2009-01-01
We study the properties of strange and charm mesons in hot and dense matter within a self-consistent coupled-channel approach for the experimental conditions of density and temperature expected for the CBM experiment at FAIR/GSI. The in-medium solution at finite temperature accounts for Pauli blocking effects, mean-field binding of all the baryons involved, and meson self-energies. We analyze the behaviour in this hot and dense environment of dynamically-generated baryonic resonances together with the evolution with density and temperature of the strange and open-charm meson spectral functions. We test the spectral functions for strange mesons using energy-weighted sum rules and finally discuss the implications of the properties of charm mesons on the D_{s0}(2317) and the predicted X(3700) scalar resonances.
From quark drops to quark stars. Some aspects of the role of quark matter in compact stars
International Nuclear Information System (INIS)
We review some recent results about the mechanism of deconfinement of hadronic matter into quark matter in cold neutron stars and protoneutron stars. We discuss the role of finite-size effects and the relevance of temperature and density fluctuations on the nucleation process. We also examine the importance of surface effects for mixed phases in hybrid stars. A small drop of quark matter nucleated at the core of a compact star may grow if the conversion is sufficiently exothermic. In such a case, it may trigger the burning of the stellar core and even the whole star if quark matter is absolutely stable. We explore the physical processes that occur inside the flame and analyze the hydrodynamic evolution of the combustion front. In the last part of this review, we focus on hybrid stars using the Nambu-Jona-Lasinio (NJL) model with scalar, vector and 't Hooft interactions, paying particular attention to a generalized non-standard procedure for the choice of the ''bag constant''. We also describe the non-radial oscillation modes of hadronic, hybrid and strange stars with maximum masses above 2M CircleDot and show that the frequency of the p1 and g fluid modes contains key information about the internal composition of compact objects. (orig.)
From quark drops to quark stars. Some aspects of the role of quark matter in compact stars
Lugones, Germán
2016-03-01
We review some recent results about the mechanism of deconfinement of hadronic matter into quark matter in cold neutron stars and protoneutron stars. We discuss the role of finite-size effects and the relevance of temperature and density fluctuations on the nucleation process. We also examine the importance of surface effects for mixed phases in hybrid stars. A small drop of quark matter nucleated at the core of a compact star may grow if the conversion is sufficiently exothermic. In such a case, it may trigger the burning of the stellar core and even the whole star if quark matter is absolutely stable. We explore the physical processes that occur inside the flame and analyze the hydrodynamic evolution of the combustion front. In the last part of this review, we focus on hybrid stars using the Nambu-Jona-Lasinio (NJL) model with scalar, vector and 't Hooft interactions, paying particular attention to a generalized non-standard procedure for the choice of the "bag constant". We also describe the non-radial oscillation modes of hadronic, hybrid and strange stars with maximum masses above 2M_{odot} and show that the frequency of the p1 and g fluid modes contains key information about the internal composition of compact objects.
From quark drops to quark stars. Some aspects of the role of quark matter in compact stars
Energy Technology Data Exchange (ETDEWEB)
Lugones, German [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Santo Andre (Brazil)
2016-03-15
We review some recent results about the mechanism of deconfinement of hadronic matter into quark matter in cold neutron stars and protoneutron stars. We discuss the role of finite-size effects and the relevance of temperature and density fluctuations on the nucleation process. We also examine the importance of surface effects for mixed phases in hybrid stars. A small drop of quark matter nucleated at the core of a compact star may grow if the conversion is sufficiently exothermic. In such a case, it may trigger the burning of the stellar core and even the whole star if quark matter is absolutely stable. We explore the physical processes that occur inside the flame and analyze the hydrodynamic evolution of the combustion front. In the last part of this review, we focus on hybrid stars using the Nambu-Jona-Lasinio (NJL) model with scalar, vector and 't Hooft interactions, paying particular attention to a generalized non-standard procedure for the choice of the ''bag constant''. We also describe the non-radial oscillation modes of hadronic, hybrid and strange stars with maximum masses above 2M {sub CircleDot} and show that the frequency of the p{sub 1} and g fluid modes contains key information about the internal composition of compact objects. (orig.)
Measurements of strangeness production in the STAR experiment at RHIC
Energy Technology Data Exchange (ETDEWEB)
Wilson, W.K. [Wayne State Univ., Detroit, MI (United States)
1995-07-15
Simulations of the ability of the STAR (Solenoidal Tracker at RHIC) detector to measure strangeness production in central Au+Au collisions at RHIC are presented. Emphasis is placed on the reconstruction of short lived particles using a high resolution inner tracker. The prospects for performing neutral kaon interferometry are discussed. Simulation results for measurements of strange and multi-strange baryons are presented.
Instability of the hedgehog shape for the octet baryon in the chiral quark soliton model
Akiyama, S; Akiyama, Satoru; Futami, Yasuhiko
2003-01-01
In this paper the stability of the hedgehog shape of the chiral soliton is studied for the octet baryon with the SU(3) chiral quark soliton model. The strangeness degrees of freedom are treated by a simplified bound-state approach, which omits the locality of the kaon wave function. The mean field approximation for the flavor rotation is applied to the model. The classical soliton changes shape according to the strangeness. The baryon appears as a rotational band of the combined system of the deformed soliton and the kaon.
Understanding penta quark with various quark models
Ping, J; Wang, F; Goldman, T; Ping, Jialun; Qing, Di; Wang, Fan
2004-01-01
The pentaquark state recently discovered has been studied with three quark models which either fit the nucleon spin structure or the $NN$ scattering. A minimum $\\Theta^+$ mass of 1620 MeV is obtained both for the ${1/2}^\\pm$ state. The mixing of various color structure configurations, which would reduce the mass of the penta-quark state, should be taking into account in the calculation of penta-quark mass.
Strangeness Vector and Axial-Vector Form Factors of the Nucleon
Directory of Open Access Journals (Sweden)
Pate Stephen
2014-03-01
Full Text Available A revised global fit of electroweak ep and vp elastic scattering data has been performed, with the goal of determining the strange quark contribution to the vector and axial-vector form factors of the nucleon in the momentum-transfer range 0 < Q2 < 1 GeV2. The two vector (electric and magnetic form factors GsE(Q2 and GsM(Q2 are strongly constrained by ep elastic scattering data, while the major source of information on the axial-vector form factor GsA(Q2 is vp scattering data. Combining the two kinds of data into a single global fit makes possible additional precision in the determination of these form factors, and provides a unique way to determine the strange quark contribution to the nucleon spin, ΔS , independently of leptonic deep-inelastic scattering. The fit makes use of data from the BNL-E734, SAMPLE, HAPPEx, G0, and PVA4 experiments; we will also compare the result of the fit with recent data from MiniBooNE, and anticipate how this fit can be improved when new data from MicroBooNE become available.
Compositeness of the strange, charm and beauty odd parity $\\Lambda$ states
Garcia-Recio, C; Nieves, J; Salcedo, L L; Tolos, L
2015-01-01
We study the dependence on the quark mass of the compositeness of the lowest-lying odd parity hyperon states. Thus, we pay attention to $\\Lambda-$like states in the strange, charm and beauty, sectors which are dynamically generated using a unitarized meson-baryon model. In the strange sector we use an SU(6) extension of the Weinberg-Tomozawa meson-baryon interaction, and we further implement the heavy-quark spin symmetry to construct the meson-baryon interaction when charmed or beauty hadrons are involved. In the three examined flavor sectors, we obtain two $J^P=1/2^-$ and one $J^P=3/2^-$ $\\Lambda$ states. We find that the $\\Lambda$ states which are bound states (the three $\\Lambda_b$) or narrow resonances (one $\\Lambda(1405)$ and one $\\Lambda_c(2595)$) are well described as molecular states composed of $s$-wave meson-baryon pairs. The $\\frac{1}{2}^-$ wide $\\Lambda(1405)$ and $\\Lambda_c(2595)$ as well as the $\\frac{3}{2}^-$ $\\Lambda(1520)$ and $\\Lambda_c(2625)$ states display smaller compositeness and so they...
Evidence for strange stars from joint observation of harmonic absorption bands and of redshift
Bagchi, M; Dey, M D J; Bagchi, Manjari; Ray, Subharthi; Dey, Mira Dey & Jishnu
2006-01-01
From recent reports on terrestrial heavy ion collision experiments it appears that one may not obtain information about the existence of asymptotic freedom (AF) and chiral symmetry restoration (CSR) for quarks of QCD at high density. This information may still be obtained from compact stars - if they are made up of strange quark matter. Very high gravitational redshift lines (GRL), seen from some compact stars, seem to suggest high ratios of mass and radius (M/R) for them. This is suggestive of strange stars (SS) and can in fact be fitted very well with SQM equation of state deduced with built in AF and CSR. In some other stars broad absorption bands appear at about ~ 0.3 keV and multiples thereof, that may fit in very well with resonance with harmonic compressional breathing mode frequencies of these SS. Emission at these frequencies are also observed in six stars. If these two features of large GRL and BAB were observed together in a single star, it would strengthen the possibility for the existence of SS i...
Compositeness of the strange, charm, and beauty odd parity Λ states
Garcia-Recio, C.; Hidalgo-Duque, C.; Nieves, J.; Salcedo, L. L.; Tolos, L.
2015-08-01
We study the dependence on the quark mass of the compositeness of the lowest-lying odd parity hyperon states. Thus, we pay attention to Λ -like states in the strange, charm, and beauty sectors which are dynamically generated using a unitarized meson-baryon model. In the strange sector we use a SU(6) extension of the Weinberg-Tomozawa meson-baryon interaction, and we further implement the heavy-quark spin symmetry to construct the meson-baryon interaction when charmed or beauty hadrons are involved. In the three examined flavor sectors, we obtain two JP=1 /2- and one JP=3 /2- Λ states. We find that the Λ states which are bound states (the three Λb) or narrow resonances [one Λ (1405 ) and one Λc(2595 )] are well described as molecular states composed of s -wave meson-baryon pairs. The 1/2- wide Λ (1405 ) and Λc(2595 ) as well as the 3/2- Λ (1520 ) and Λc(2625 ) states display smaller compositeness so they would require new mechanisms, such as d -wave interactions.
A new deterministic model of strange stars
Rahaman, Farook; Chakraborty, Koushik; Kuhfittig, P. K. F.(Department of Mathematics, Milwaukee School of Engineering, 53202-3109, Milwaukee, WI, USA); Shit, G. C.; Rahman, Mosiur
2014-01-01
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 t...
Stability of realistic strange stars (RSS)
Bhowmick, S; Dey, M; Ray, S; Ray, R; Bhowmick, Siddhartha; Dey, Jishnu; Dey, Mira; Ray, Subharthi; Ray, Ranjan
2001-01-01
Strange stars (SS) calculated from a realistic equation of state (EOS) are very stable, for example under fast rotation but have a soft surface, on which ripples may occur when radiation is emitted close to it. We suggest this as a natural explanation of the fluctuations observed in the intensity profile of X-ray pulsars. In contrast, SS based on EOS derived from the bag models (Bag SS) are less stable against fast rotation and do not have a hard surface and cannot explain these ripples. There are other important differences between Bag SS and the SS, based on a realistic EOS, which we call realistic strange stars (RSS).
Strangeness Suppression in Proton-Proton Collisions
Drescher, Hans-Joachim; Aichelin, Joerg; Werner, Klaus
2001-01-01
We analyse strangeness production in proton-proton (pp) collisions at SPS and RHIC energies, using the recently advanced NeXus approach. After having verified that the model reproduces well the existing data, we interpret the results: strangeness is suppressed in proton-proton collisions at SPS energy as compared to electron-positron (e+e-) annihilation due to the limited masses of the strings produced in the reaction, whereas high energy pp and e+e- collisions agree quantitatively . Thus str...
Indian Academy of Sciences (India)
Yuji Takeuchi
2012-10-01
Since the top quark was discovered at Tevatron in 1995, many top quark properties have been measured. However, the top quark is still interesting due to unique features which originate from the extremely heavy mass, and providing various test grounds on the Standard Model as well as searches for a new physics. Though the measurements of the top quark had been performed only at Tevatron so far, LHC is now ready for measurements with more top quarks than Tevatron. In this article, recent measurements of top quark properties from Tevatron (CDF and DØ) as well as LHC (ATLAS and CMS) are presented.