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In this paper we present an approach to study the radiative decay modes of the J/{psi} into a photon and one of the tensor mesons f{sub 2}(1270), f' {sub 2}(1525), as well as the scalar ones f{sub 0}(1370) and f{sub 0}(1710). Especially, we compare predictions that emerge from a scheme where the states appear dynamically in the solution of vector meson-vector meson scattering amplitudes to those from a (admittedly naive) quark model. We provide evidence that it might be possible to distinguish amongst the two scenarios, once improved data are available. (orig.)

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The naive time reversal odd (T-odd) parton distribution $h_{1}^{\\perp}$, the so-called Boer-Mulders function, for both $u$- and $d$-quarks is considered in the diquark spectator model. While other approaches give evidence that the signs of the Boer-Mulders function for both flavors $u$ and $d$ are the same and negative, previous caculations in the diquark-spectator model found $h_{1}^{\\perp(u)}$ and $h_{1}^{\\perp(d)}$ have differnet signs. The flavor dependence is of significance for the analysis of the azimuthal $\\cos(2\\phi)$ asymmetries in unpolarized SIDIS and DY-processes, as well as for the overall physical understanding of the distribution of transversely polarized quarks in unpolarized nucleons. We find substantial differences with previous work. In particular we obtain estimates of the zeroth, half and first moments of Boer-Mulders functions that are negative over the ...

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The strange quark star is investigated within the enlarged SU(3) Nambu-Jona-Lasinio model. The stable quark star can exist until a maximal configuration with {rho}{sub m}=3.1x10{sup 15} g cm{sup -3} with M{sub m}=1.61 M{sub circle} and R{sub m}=8.74 km is reached. Strange quarks appear for density above {rho}{sub c}=9.84 g cm{sup -3} for the quark star with radius R{sub c}=8.003 km and M{sub c}=0.77 M{sub circle}. A comparison of quark star properties obtained in the quark mean-field approach to a neutron star model constructed within the relativistic mean-field theory is presented. (author)

International Nuclear Information System (INIS)

Quark models of production of cumulative particles and the EMC effect are analyzed. It is shown that all these models are characterized by a universal relation between the spectrum of cumulative nucleons and the cross section for cumulative particles containing valence quarks of the nucleus. This relation is tested for the deuteron, and the role of secondary nuclear processes for heavy nuclei is discussed. It is noted that the ''sea'' cumulative particles (K"-, p-bar) are particularly important for understanding the nature of the difference between the structure functions of a nucleus and of a free nucleon.

CERN Document Server

It is a pity that the real state of matter in pulsar-like stars is still not determined confidently because of the uncertainty about cold matter at supranuclear density, even 40 years after the discovery of pulsar. Nuclear matter (related to neutron stars) is one of the speculations for the inner constitution of pulsars even from the Landau's time more than 70 years ago, but quark matter (related to quark stars) is an alternative due to the fact of asymptotic freedom of interaction between quarks as the standard model of particle physics develops since 1960s. Therefore, one has to focus on astrophysical observations in order to answer what the nature of pulsars is. In this presentation, I would like to summarize possible observational evidence/hints that pulsar-like stars could be quark stars, and to address achievable clear evidence for quark stars in the ...

International Nuclear Information System (INIS)

We examine the electric and magnetic strange form factors of the nucleon in the pseudoscalar-vector SU(3) Skyrme model, with special emphasis on the effects of isospin symmetry breaking (ISB). It is found that ISB has a nontrivial effect on the strange vector form factors of the nucleon and its contribution to the nucleon strangeness is significantly larger than one might naively expect. Our calculations and discussions may be of some significance for the experimental extraction of the authentic strangeness.

Science.gov (United States)

We calculate the electromagnetic form factors of a bound proton. The chiral quark-soliton model provides the quark and antiquark substructure of the proton, which is embedded in nuclear matter. This procedure yields significant modifications of the form factors in the nuclear environment. The sea quarks are almost completely unaffected, and serve to mitigate the valence quark effect. In particular, the ratio of the isoscalar electric to the isovector magnetic form factor decreases by 20% at Q{sup 2}=1 GeV{sup 2} at nuclear density, and we do not see a strong enhancement of the magnetic moment.

Energy Technology Data Exchange (ETDEWEB)

Quark models of production of cumulative particles and the EMC effect are analyzed. It is shown that all these models are characterized by a universal relation between the spectrum of cumulative nucleons and the cross section for cumulative particles containing valence quarks of the nucleus. This relation is tested for the deuteron, and the role of secondary nuclear processes for heavy nuclei is discussed. It is noted that the ''sea'' cumulative particles (K/sup -/, p-bar) are particularly important for understanding the nature of the difference between the structure functions of a nucleus and of a free nucleon.

International Nuclear Information System (INIS)

The A-dependence of the nuclear structure functions is described rather well within the framework of the quark-parton-flucton model of nucleus. 16 refs. (author).

CERN Document Server

In the littlest Higgs model with T-parity (LHT), the mirror quarks have flavor structures and will contribute to the top quark flavor changing neutral current. In this work, we perform an extensive investigation of the top quark rare three-body decays $t\\rightarrow cVV (V=\\gamma,Z,g)$ and $t\\rightarrow cf\\bar{f} (f=b,\\tau,\\mu,e)$ at one-loop level. Our results show that the branching ratios of $t\\rightarrow cgg$ and $t\\rightarrow cb\\bar{b}$ could reach $\\mathcal {O}(10^{-3})$ in the favorite parameter space of the littlest Higgs model with T-parity, which implies that these decays may be detectable at the LHC or ILC, while for the other decays, their rates are too small to be observable at the present or future colliders.

Energy Technology Data Exchange (ETDEWEB)

At future [gamma][gamma] colliders copious production of [ital t] [bar t] pairs is possible. This would allow for a detailed investigation of the interactions involving the top quark. We propose some correlations which are sensitive to [ital t] [bar t] final state interactions and we compute the QCD and standard model Higgs boson contributions to these correlations. A correlation resulting from the QCD induced transverse polarization of top quarks is found to be sizable and measurable at a high energy [ital e][sup +][ital e][sup [minus

International Nuclear Information System (INIS)

At future #gamma##gamma# colliders copious production of t bar t pairs is possible. This would allow for a detailed investigation of the interactions involving the top quark. We propose some correlations which are sensitive to t bar t final state interactions and we compute the QCD and standard model Higgs boson contributions to these correlations. A correlation resulting from the QCD induced transverse polarization of top quarks is found to be sizable and measurable at a high energy e"+e"- collider, which is operated as a photon collider through backscattering of laser photons, at an integrated luminosity of 10 fb"-"1.

Energy Technology Data Exchange (ETDEWEB)

We suggest a procedure for estimating uncertainties in neutron cross sections calculated with a nuclear model descriptive of a specific mass region. It applies standard error propagation techniques, using a model-parameter covariance matrix. Generally, available codes do not generate covariance information in conjunction with their fitting algorithms. Therefore, we resort to estimating a relative covariance matrix a posteriori from a statistical examination of the scatter of elemental parameter values about the regional representation. We numerically demonstrate our method by considering an optical-statistical model analysis of a body of total and elastic scattering data for the light fission-fragment mass region. In this example, strong uncertainty correlations emerge and they conspire to reduce estimated errors to some 50% of those obtained from a naive uncorrelated summation in quadrature. 37 ...

Energy Technology Data Exchange (ETDEWEB)

We discuss the description of the proton structure function within the dipole factorization framework. We parameterize the forward dipole amplitude to account for saturation as predicted by the small-x QCD evolution equations. Contrarily to previous models, the saturation scale does not decrease when taking heavy quarks into account. We show that the same dipole amplitude also allows to reproduce diffractive data and exclusive vector meson production.

Energy Technology Data Exchange (ETDEWEB)

We review the physics of structure functions at low Q{sup 2}, focusing on the phenomenon of quark-hadron duality and the resonance-scaling transition, both phenomenologically and in the context of quark models. We also present a new implementation of target mass corrections to nucleon structure functions which, unlike existing treatments, has the correct kinematic threshold behavior at finite Q{sup 2} in the x -> 1 limit.

International Nuclear Information System (INIS)

We discuss the consequence of local duality for elastic scattering, and derive a model-independent equation between structure functions at x ? 1 and elastic electromagnetic form factors. Then the electromagnetic form factors of proton are discussed using the quark-hadron duality theory. We also debate the form factor of proton in a bound state. It may be an effective approach to study the form factor of proton in media.

CERN Document Server

Some extensions of the Standard Model often predict a Z'gauge boson which mediates flavor-changing neutral-current (FCNC) interaction between up and top quarks. These new physics models are phenomenologically attractive because they can explain the top quark forward-backward asymmetry $A^t_FB$ measured recently by the Tevatron collider. In addition, they will induce the top quark FCNC decays and the like-sign top pair production which can be explored at the LHC. In this work we focus on two such models (the left-right model and the $U(1)_X$ model) to investigate their correlated effects on $A^t_FB$, the FCNC decays $t -> u V (V=g,Z,\\gamma)$ and the like-sign top pair production at the LHC. We also pay special attention on the most recently measured $A^t_FB$ in the large invariant mass region. We find that under the ...

Energy Technology Data Exchange (ETDEWEB)

On the basis of the phenomenological model for baryon resonance production in lepton nucleon and lepton nucleus scattering we investigate to what extent quark hadron duality is applicable to the neutrino structure functions and how it compares with duality in electron scattering.

International Nuclear Information System (INIS)

We construct a phenomenological model which describes the dynamical chiral symmetry breaking (DCSB) of a QCD vacuum and reproduces meson spectra. Quark condensates, the pion decay constant, and meson spectra are well reproduced by the phenomenological interaction which consists of a linear confining potential, a Coulombic potential, and the close-quote t Hooft determinant interaction. In this model, the close-quote t Hooft determinant interaction plays an important role to not only the mass difference between the #eta# and #eta#"' mesons, but other meson masses through DCSB. copyright 1997 The American Physical Society.

CERN Document Server

Assuming the gluon field is well approximated by instanton configurations we derive a light quarks determinant and calculate its contribution to the specific heavy quarks correlators -- namely, the heavy quark propagator and heavy quark-aniquark correlator, receiving the instanton generated light-heavy quarks interaction terms contributions. With these knowledge we calculate the light quark contribution to the interaction between heavy quarks, which might be essential for the properties of a few heavy quarks systems.

International Nuclear Information System (INIS)

The set of nonlinear equations describing the standard model kinematics of the top quark antiquark production system in the dilepton decay channel has at most a fourfold ambiguity due to two not fully reconstructed neutrinos. Its most precise solution is of major importance for measurements of top quark properties like the top quark mass and tt spin correlations. Simple algebraic operations allow one to transform the nonlinear equations into a system of two polynomial equations with two unknowns. These two polynomials of multidegree eight can in turn be analytically reduced to one polynomial with one unknown by means of resultants. The obtained univariate polynomial is of degree 16. The number of its real solutions is determined analytically by means of Sturm's theorem, which is as well used to isolate each real solution into a unique pairwise disjoint interval. The solutions are polished by seeking the ...

CERN Document Server

We present a detailed study of the anomalous single fourth generation $t'$ quark production within the dominant Standard Model(SM) decay modes at future $e^+e^-$ colliders. We calculate the signal and background cross sections in the mass range 300-800 GeV. We also discuss the limits of $t'q\\gamma$ and $t'qZ$ ($q=u,c$) anomalous couplings as well as values of attainable integrated luminosity for 3$\\sigma$ observation limit.

CERN Document Server

In light of the recent measurements of the top quark forward-backward asymmetry at the Fermilab Tevatron experiment, which in some regions of the parameter space shows a discrepancy of 3$\\sigma$ compared to the SM prediction, we analyze top quark pair production and asymmetry in the context of left-right models both at the Tevatron and LHC. We use the minimal manifest left-right model and an asymmetric left-right model where gauge couplings and flavor mixing in the right-handed sector are allowed to differ from those in the left-handed sector. We explore the consequences of including effects from $W_R$ and $Z_R$ gauge bosons, consistent with phenomenological constraints from meson mixing and new bounds from ATLAS and CMS, for the $t \\bar{t}$ cross section, invariant mass distribution and forward-backward asymmetry at the Tevatron, and predict their values at the LHC. We show that, ...

CERN Document Server

We exhibit static solutions of multi-flavour QCD in two dimensions that have the quantum numbers of baryons and mesons, constructed out of quark and anti-quark solitons. In isolation the latter solitons have infinite energy, corresponding to the presence of a string carrying the non-singlet colour flux off to spatial infinity. When $N_c$ solitons of this type are combined, a static, finite-energy, colour singlet solution is formed, corresponding to a baryon. Similarly, static meson solutions are formed out of a soliton and an anti-soliton of different flavours. The stability of the mesons against annihilation is ensured by flavour conservation. The static solutions exist only when the fundamental fields of the bosonized Lagrangian belong to $U(N_c{\\times}N_f)$ rather than to $SU(N_c) \\times U(N_f)$. Discussion of flavour symmetry breaking requires a careful treatment of the normal ordering ambiguity. Our results can be viewed as a derivation ...

CERN Document Server

We consider the (2, 0) supersymmetric theory of tensor multiplets and self-dual strings in six space-time dimensions. Space-time diffeomorphisms that leave the string world-sheet invariant appear as gauge transformations on the normal bundle of the world-sheet. The naive invariance of the model under such transformations is however explicitly broken by anomalies: The electromagnetic coupling of the string to the two-form gauge field of the tensor multiplet suffers from a classical anomaly, and there is also a one-loop quantum anomaly from the chiral fermions on the string world-sheet. Both of these contributions are proportional to the Euler class of the normal bundle of the string world-sheet, and consistency of the model requires that they cancel. This imposes strong constraints on possible models, which are found to obey an ADE-classification. We then consider the decoupled world-sheet theory that ...

CERN Document Server

Both Grand Unified symmetries and discrete flavour symmetries are appealing ways to describe apparent structures in the gauge and flavour sectors of the Standard Model. Both symmetries put constraints on the high energy behaviour of the theory. This can give rise to unexpected interplay when building models that possess both symmetries. We investigate on the possibility to combine a Pati-Salam model with the discrete flavour symmetry S4 that gives rise to quark-lepton complementarity. Under appropriate assumptions at the GUT scale, the model reproduces fermion masses and mixings both in the quark and in the lepton sectors (the Beauty). We show that in particular the Higgs sector and the running Yukawa couplings are strongly affected by the combined constraints of the Grand Unified and family symmetries (the Beast). This in turn reduces the phenomenologically ...

CERN Document Server

Both discrete flavour symmetries and Grand Unified symmetries explain apparent structures in the mass sector of the Standard Model. A model that combines both symmetries is therefore very appealing. We construct a model with the $S_4$ flavour symmetry and the Pati-Salam unification. We show that this model can indeed explain many observable relations between the masses of the quarks and leptons and that it is predictive in the neutrino sector. However, the combination of the two symmetries leads to new complications in the Higgs sector and in the running of the renormalisation group equations.

International Nuclear Information System (INIS)

A phenomenological analysis of lifetimes of bottom and charmed hadrons within the framework of the heavy quark expansion is performed. The baryon matrix element is evaluated using the bag model and the nonrelativistic quark model. We find that bottom-baryon lifetimes follow the pattern #tau#(#OMEGA#_b)#approx =##tau#(#XI#_b"-)>#tau#(#LAMBDA#_b)#approx =##tau#(#XI#_b"0). However, neither the lifetime ratio #tau#(#LAMBDA#_b)/#tau#(B_d) nor the absolute decay rates of the #LAMBDA#_b baryon and B mesons can be explained. One way of solving both difficulties is to allow the presence of linear 1/m_Q corrections by scaling the inclusive nonleptonic width with the fifth power of the hadron mass m_H__Q rather than the heavy quark mass m_Q. The hierarchy of bottom baryon lifetimes is dramatically modified to #tau#(#LAMBDA#_b)>#tau#(#XI#_b"-)>#tau#(#XI#_b"0)>#tau#(#OMEGA#_b): The ...

Energy Technology Data Exchange (ETDEWEB)

The effectiveness of Noveko's antimicrobial filter was evaluated after 16 months of exposure to commercial swine production. The experiment involved the use of a scaled model of a commercial swine facility consisting of 2 small chambers connected by a duct containing the filters. A 5 kg naive pig was placed in the reception chamber for a period of 6 hours after aerosolization with porcine reproductive and respiratory syndrome virus (PRRSV). Blood samples from pigs were collected before and after aerosolization to test for the presence of PRRSV RNA. Only blood samples were tested for PRRSV antibodies by IDEXX 2XR ELISA. None of the 9 pigs tested were found to be infected. The study showed that the technology used to integrate the antimicrobial agent into the filter fibers allows the filter combination to withstand extreme weather and endure commercial swine production for at least 16 months, and can maintain its effectiveness to avoid ...

CERN Document Server

We discuss first the flavor mixing of the quarks, using the texture zero mass matrices. Then we study a similar model for the mass matrices of the leptons. We are able to relate the mass eigenvalues of the charged leptons and of the neutrinos to the mixing angles and can predict the masses of the neutrinos. We find a normal hierarchy - the masses are 0.004 eV, 0.01 eV and 0.05 eV. The atmospheric mixing angle is given by the mass ratios of the charged leptons and the neutrinos. we find about 40 degrees, consistent with the experiments. The mixing element, connecting the first neutrino wit the electron, is predicted to be 0.05. This prediction can soon be checked by the Daya Bay experiment.

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We discuss the origin of Bloom-Gilman duality and the relationship between resonances and scaling in deep-inelastic scattering. We present a simple quantum mechanical model which reproduces the essential features of Bloom-Gilman duality at low Q{sup 2}, and describe applications of local duality relating structure functions at x{approximately}1 and elastic electromagnetic form factors.

CERN Document Server

The basic theoretical milestones were the Sakata SU(3) symmetry, the Goldberg-Ne'eman composite model with SU(3) triplets having baryon number (1/3) and the Nambu color gauge Lagrangian. The transition was led in right and wrong directions by experiments interpreted by phenomenology. A "good" experiment on $\\bar p p$ annihilation at rest showed that the Sakata model predictions disagreed with experiment. A "bad" experiment prevented the use of the Goldberg-Ne'eman triplet model to predict the existence and masses of the of the $\\Xi^*$ and $\\Omega^-$. More "good" experiments revealed the existence and mass of the $\\Xi^*$ and the $\\Omega^-$ and the absence of positive strangeness baryon resonances, thus confirming the "tenfold way". Further "good experiments" revealed the existence of the vector meson nonet, SU(3) breaking with singlet-octet mixing and the suppression of the $\\phi \\to \\rho \\pi$ decay. These led to ...

CERN Document Server

In models with dynamical electroweak symmetry breaking, this breaking is normally communicated to quarks and leptons by a set of vector bosons with masses generated via sequential breaking of a larger gauge symmetry. In reasonably ultraviolet-complete theories of this type, the number of stages of breaking of the larger gauge symmetry is usually equal to the observed number of quark and lepton generations, $N_{gen.}=3$. Here we investigate the general question of how the construction and properties of these models depend on $N_{gen.}$, regarded as a variable. We build and analyze models with illustrative values of $N_{gen.}$ different from 3 (namely, $N_{gen.}=1,2,4$) that exhibit the necessary sequential symmetry breaking down to a strongly coupled sector that dynamically breaks electroweak symmetry. Our results for variable $N_{gen.}$ show that one can robustly obtain, for this ...

International Nuclear Information System (INIS)

The 'elementary' particle physics began in 1935, when Hideki Yukawa published his pioneering pi-meson theory, and the problem of strong interaction was finally solved 40 years later by the establishment of the Standard Model. The composite models of hadrons by the Sakata school and Sin-itiro Tomonaga's renormalization theory for quantum electrodynamics played essential roles for finding this beautiful solution. It is really surprising that it took only 40 years to solve such desperately difficult problem. The 'elementary' particle physics then split into two new fields, quark-hadron physics' and 'unified (ultimate) theory of particle physics', which are now 30 years old already. (author)

International Nuclear Information System (INIS)

Nucleon and meson effective masses in the nonlinear relativistic mean-field theory introducing a nonlinear #omega#-#rho# and #sigma# coupling motivated by the quark-meson coupling model is explored. It is shown that, in contrast to the usual Walecka model, not only the effective nucleon mass m_e_f_f_,_N but also the effective #sigma#,#rho# meson masses (m_e_f_f_#sigma#,m_e_f_f_,_#rho#) and the effective #omega# meson mass m_e_f_f_,_#omega# are nucleon density dependent. (author)

CERN Document Server

We present the complete next-to-leading order (NLO) QCD corrections to the top quark associated with $\\gamma$ production induced by model-independent $tq\\gamma$ and $tqg$ flavor-changing neutral-current (FCNC) couplings at hadron colliders, respectively. We also consider the mixing effects between the $tq\\gamma$ and $tqg$ FCNC couplings for this process. Our results show that, for the $tq\\gamma$ couplings, the NLO QCD corrections can enhance the total cross sections by about 50% and 40% at the Tevatron and LHC, respectively. Including the contributions from the $tq\\gamma$, $tqg$ FCNC couplings and their mixing effects, the NLO QCD corrections can enhance the total cross sections by about 50% for the $tu\\gamma$ and $tug$ FCNC couplings, and by about the 80% for the $tc\\gamma$ and $tcg$ FCNC couplings at the LHC, respectively. Moreover, the NLO corrections reduce the dependence of the total cross section on the renormalization and ...

International Nuclear Information System (INIS)

We review some interesting virtual effects from the minimal supersymmetric model (MSSM) at #gamma##gamma# colliders. We conclude that in the research respects, such as supersymmetric particle pair production, CP-violation and electroweak-like one-loop corrections in top quark pair production, the FCNC in the R_p-violating MSSM, linear collider (LC) operating in photon-photon collision mode provides powerful facilities in the measurements of new physics objects. For a precise and thorough study of the new physics, the investigation of the supersymmetric quantum effects is necessary. (author)

International Nuclear Information System (INIS)

The Gamma Physics (GaP) program of physical phenomena investigation is proposed on #gamma#p, #gamma#e and #gamma##gamma# colliders at TeV energies. The program contains specialized software (CompHEP system) created for automation of particle interaction processes calculations in the framework of various gauge models. Preliminary physical results are presented (heavy quark production, W, Z production, supersymmetry etc.), and further software development is suggested. (R.P.) 22 refs., 8 figs., 4 tabs.

CERN Document Server

We discuss the recent excess seen by the CDF Collaboration in the dijet invariant mass distribution produced in association with a $W$ boson. We analyze the possibility of such a signal within the context of a $U(1)_X$ Stueckelberg extension of the Standard Model where the new gauge boson couples only to quarks. In addition to the analysis of the $Wjj$ anomaly we also discuss the production of $Zjj$ and $\\gamma jj$ at the Tevatron. The analysis is then extended to the Large Hadron Collider with $\\sqrt{s}=7 {\\rm TeV}$ and predictions for the dijet signals are made.

Energy Technology Data Exchange (ETDEWEB)

Short communication. 3 refs.

International Nuclear Information System (INIS)

Russian 2003 p. 74 Russian Federation Leksin, GA Inst. Teoreticheskoj

CERN Document Server

In light of the recent discovery of the importance of the isovector EMC effect for the interpretation of the NuTeV determination of sin^2 theta_W, it seems timely to reassess the central value and the errors on this fundamental Standard Model parameter derived from the NuTeV data. We also include earlier work on charge symmetry violation and the recent limits on a possible asymmetry between s and \\bar{s} quarks. With these corrections we find a revised NuTeV result of sin^2 theta_W = 0.2232 \\pm 0.0013(stat) \\pm 0.0024(syst), which is in excellent agreement with the running of sin^2 theta_W predicted by the Standard Model.

International Nuclear Information System (INIS)

We present the effects of heavy CP-even (H) and CP-odd (A) Higgs bosons on the production cross section of the process #gamma##gamma##->#tt at the energy around the mass poles of the Higgs bosons. It is found that interference between H and A with small mass gap, as well as the ones between Higgs bosons and continuum, contributes to the cross section, if the photon beams are polarized and if we observe the helicity of the top quarks. It is demonstrated in the framework of the minimal supersymmetric extension of the standard model that the H and A contributions can be sizable at future #gamma##gamma# colliders for small values of tan #beta#. The methods to measure the CP-parity of the Higgs boson are also presented. The statistical significance of detecting the Higgs signals and measuring the Higgs CP-parity is evaluated. (orig.)

Energy Technology Data Exchange (ETDEWEB)

This thesis describes the analysis of the semileptonic decay D{sup 0} {yields} {bar K}{sup 0} {pi}{sup -} {mu}{sup +}{nu} using FOCUS data. FOCUS is a fixed target experiment at Fermilab that studies the physics of the charm quark. Particles containing charm are produced by photon-gluon fusion from the collision of a photon beam on a BeO target. The experiment is characterized by excellent vertex resolution and particle identification. The spectrometer consists of three systems for track reconstruction (two silicon systems and one multiwire proportional chamber system) and two magnets of opposite polarity. The polarity of the magnet is such that the events of e{sup +}e{sup -} pairs produced in the target (which constitutes the main background) travel through a central opening in the detectors without interactions. Particle momentum is measured from the deflection angle in the magnets. Three multicell Cerenkov counters are used for charged particle identification ...

International Nuclear Information System (INIS)

Possible mechanisms of the cumulative production of particles in the processes of high momentum transfers to complex systems are discussed. Production of the multi-nucleon systems, the so-called fluctons, during collision of a high-energy particle with a nucleus, is proposed as a most realistic explanation of the cumulative effect. A probability of the flucton production in nucleus and its interaction with the incident particle are investigated. A possible origin of fluctons, considered, in the framework of the quark bag model, as quasistable states with the definite coupling energy and the lifetime, is studied. A probability for the presence of a flucton, as multibaryon configuration in a nucleus is evaluated. The production of multibaryon configurations in a nucleus is demonstrated to show up as a presence of strong multiparticle repulsion at small distances, which cannot be reduced only to two-particle interactions.

Energy Technology Data Exchange (ETDEWEB)

A number of systems which can elucidate physics beyond the standard model are investigated. The production of axions by a network of cosmic strings in the early universe is calculated. This allows an upper bound to be placed on the axion decay constant, and provides the preferred Peccei-Quinn symmetry breaking scale for axions to make up the dark matter of the universe. Models of neutrino mass arising from strong interactions are investigated. These models possess a massless up quark, thereby solving the strong CP problem. A systematic analysis of the contributions to time reversal violating atomic and molecular electric dipole moments is presented. Specific contributions from the supersymmetric standard model are calculated. The contributions arising from the QCD vacuum angle are also discussed. Prospects for detecting the axion by its long range coherent force are related to ...

CERN Document Server

Precise measurements of the top quark decay properties at hadron colliders offer interesting new possibilities of testing the standard model. At the same time, recent intriguing experimental results concerning CP violation in the B_d and B_s systems have stimulated many studies of physics beyond the standard model. We investigate anomalous t W d_j interactions as a possible source of new effects in B_{d,s} - bar B_{d,s} oscillations within a model independent approach based on the assumptions of Minimal Flavor Violation. After matching our effective operators onto the low-energy effective Lagrangian describing B_{d,s} meson mixing and evolving it down to the B-mass scale, we extract the preferred ranges of the anomalous t W d_j interactions at the weak scale. These values are then compared to previously considered constraints coming from the rare radiative B --> X_s gamma decay. Finally, we ...

Energy Technology Data Exchange (ETDEWEB)

A review of recent work in nuclear physics is presented. The paper gives a broad discussion of research goals in nuclear structure, quark-gluon degrees of freedom, quark-gluon plasma, symmetries, and rare decays. (DWL)

UK PubMed Central (United Kingdom)

β₂ integrins are of critical importance for leukocyte extravasation through vascular endothelia and for T cell activation. To elucidate the role of β₂ integrins...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

We analyze spin correlations between top quark and anti-top quark produced at polarized e{sup +} e{sup -} and {gamma}{gamma} colliders. We consider a generic spin basis to find a strong spin correlation. Optimal spin decompositions for top quark pair are presented for e{sup +}e{sup -} and {gamma}{gamma} colliders. We show the cross- section in these bases and discuss the characteristics of results.

CERN Document Server

At the beginning of the seventies, physicists discovered a new scale in the matter structure. Protons and neutrons, components of the atomic nucleus, seemed to be constituted by even more elementar particles: the quarks. But while they seemed to move freely inside the protons, it was impossible to isolate one of these quarks. The Nobel Prize for physics rewarded the explanation of this phenomenon (3 pages)

CERN Document Server

The "texture zero mass matrices" for the quarks and leptons describe very well the flavor mixing of the quarks and leptons. We can calculate the angles of the unitarity triangle. We expect the angle alpha of the unitarity triangle to be 90 degrees. The masses of the neutrinos can be calculated - they are very small, the largest neutrino mass is 0.05 eV. We calculated the matrix element of the mixing matrix, relevant for the reactor mixing angle. It can be measured in the near future in the DAYA BAY experiment.

Energy Technology Data Exchange (ETDEWEB)

We present a calculation of the charmonium spectrum with three flavors of dynamical staggered quarks from gauge configurations that were generated by the MILC collaboration. We use the Fermilab action for the valence charm quarks. Our calculation of the spin-averaged 1P-1S and 2S-1S splittings yields a determination of the strong coupling, with {alpha}{sub {ovr MS}}(M{sub Z}) = 0.119(4).

CERN Document Server

In the presence of the T-parity violating Wess-Zumino-Witten (WZW) anomaly term, the otherwise stable heavy photon A_H in the Littlest Higgs model with T-parity (LHT) decays to either Standard Model (SM) gauge boson pairs, or to SM fermions via loop diagrams. We make a detailed study of the collider signatures where the A_H can be reconstructed from invariant mass peaks in the opposite sign same flavor dilepton or the four-lepton channels. This enables us to obtain information about the fundamental symmetry breaking scale f in the LHT and thereby the low-lying mass spectrum of the theory. In addition, indication of the presence of the WZW term gives us hints of the possible UV completion of the LHT via strong dynamics. The crucial observation is that the sum of all production processes of heavy T-odd quark pairs has a sizeable cross-section at the LHC and these T-odd particles eventually all cascade decay down to the heavy ...

CERN Document Server

Three-flavor lattice QCD simulations and two-loop perturbation theory are used to make the most precise determination to date of the strange-, up-, and down-quark masses, $m_s$, $m_u$, and $m_d$, respectively. Perturbative matching is required in order to connect the lattice-regularized bare- quark masses to the masses as defined in the \\msbar scheme, and this is done here for the first time at next-to-next-to leading (or two-loop) order. The bare-quark masses required as input come from simulations by the MILC collaboration of a highly-efficient formalism (using so-called ``staggered'' quarks), with three flavors of light quarks in the Dirac sea; these simulations were previously analyzed in a joint study by the HPQCD and MILC collaborations, using degenerate $u$ and $d$ quarks, with masses as low as $m_s/8$, and two values of the lattice spacing, with chiral ...

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We present a supersymmetric renormalization group fixed point determination of the third generation fermion masses, in which the large mass ratio between the top and bottom quarks is attributed to a hierarchy in the vacuum expectation values of the two Higgs doublets. Above a supersymmetry breaking scale, M{sub s}, we use the minimal supersymmetric standard model with a transition at M{sub s} to the standard model with only one Higgs- doublet effective. The mass predictions result from renormalization group evolution of large Yukawa couplings at M{sub x} {approximately} 1016 GeV. Averaging over a wide range of these couplings, not subject to any symmetry requirements, gives m{sub t} = 184.3{plus_minus}6.8 GeV, m{sub b} = 4.07{plus_minus}0.33 GeV, m{sub {tau}} = 1.78{plus_minus}0.33 GeV and a light Higgs mass m{sub h}o = 121.8{plus_minus}4.3 GeV for M{sub s} = 1 TeV and {alpha}{sub s} (M{sub z}) = 0.125.

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Understanding the structure of the nucleon is a fundamental question in subatomic physics, and it has been under intensive investigation for the last several years. Modern research focuses in particular on the spin structure of the nucleon. Experimental and theoretical investigations worldwide over the last few decades have established that, contrary to nave quark model expectations, quarks carry only about 30% of the totd spin of the proton. The origin of the remaining spin is the key question in current hadronic physics and also the major driving forces for the current and future experiments, such as RHIC and CEBAF in US, JPARC in Japan, COMPASS at CERN in Europe, FAIR at GSI in Germany. Among these studies, the transverse-spin physics develops actively and rapidly in the last few years. Recent studies reveal that transverse-spin physics is closely related to many fundamental properties of the QCD dynamics such as the ...

CERN Document Server

Using the finite-range regularisation (FRR) of chiral effective field theory, the chiral extrapolation formula for the vector meson mass is derived for the case of partially-quenched QCD. We re-analyse the dynamical fermion QCD data for the vector meson mass from the CP-PACS collaboration. A global fit, including finite lattice spacing effects, of all 16 of their ensembles is performed. We study the FRR method together with a naive polynomial approach and find excellent agreement ~1% with the experimental value of M_rho from the former approach. These results are extended to the case of the nucleon mass.

International Nuclear Information System (INIS)

An attempt to classify experimental data and to present new approach for the problem of cumulative production of particles and high-transverse momentum particles (#pi#"#+-#, k"#+-#, p, p-bar, d) on Li"6, Be, Mg, Si, "5"4","5"6","5"8Fe, "5"8","6"1","6"4Ni, Cu, "6"4Zn, "1"1"2","1"1"8","1"2"4Sn, "1"4"4","1"5"4Sm, "1"8"2","1"8"6W, U nuclei is made in the review. Particle cumulative production, quark-parton structure function, A dependence of particle production on nuclei and in nuclear collisions and A dependence of inclusive cross sections of particle cumulative production are discussed. Reactions with dissociation on nucleons of deuteron, helium and compound nuclei are considered. Possibility of unified description of different processes is discussed in terms of nucleus flucton model. 35 refs.; 22 figs.

CERN Document Server

We present several recent results from the BaBar collaboration in the areas of initial state radiation physics and transition form factors. An updated study of the processes e+e- -> K+K-pi+pi- and e+e- -> K+K-pi0pi0 provides an improved understanding of the Y(2175) meson. A very precise study of the process e+e- -> pi+pi- improves the precision on the calculated anomalous magnetic moment of the muon and provides by far the best information on excited rho states. Our previous measurements of the timelike transition form factors (TFF) of the eta and eta' mesons at Q^2=112 GeV^2, combined with new measurements of the their spacelike TFFs and those of the pi0 and eta_c mesons, provide powerful tests of QCD and models of the distribution amplitudes of quarks inside these mesons. The eta_c TFF shows the expected behavior over the Q^2 range 1-50 GeV^2, and we are sensitive to next-to-leading-order QCD corrections. The eta and eta' TFFs are ...

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The $e p\\to e^\\prime p \\rho^0$ reaction has been measured, using the 5.754 GeV electron beam of Jefferson Lab and the CLAS detector. This represents the largest ever set of data for this reaction in the valence region. Integrated and differential cross sections are presented. The $W$, $Q^2$ and $t$ dependences of the cross section are compared to theoretical calculations based on $t$-channel meson-exchange Regge theory on the one hand and on quark handbag diagrams related to Generalized Parton Distributions (GPDs) on the other hand. The Regge approach can describe at the $\\approx$ 30% level most of the features of the present data while the two GPD calculations that are presented in this article which succesfully reproduce the high energy data strongly underestimate the present data. The question is then raised whether this discrepancy originates from an incomplete or inexact way of modelling the GPDs or the associated hard scattering ...

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We investigate the interplay of quark and meson degrees of freedom in a physical state representing a near-threshold resonance for the case of a single continuum channel. We demonstrate that such a near-threshold resonance may possess quite peculiar properties if both quark and meson dynamics generate weakly coupled near-threshold poles in the S -matrix. In particular, the scattering t -matrix may possess zeros in this case. We also discuss possible implications for production reactions as well as studies within lattice QCD. (orig.)

International Nuclear Information System (INIS)

The top quark antiquark production system in the dilepton decay channel is described by a set of equations which is nonlinear in the unknown neutrino momenta. Its most precise and least time consuming solution is of major importance for measurements of top quark properties like the top quark mass and tt spin correlations. The initial system of equations can be transformed into two polynomial equations with two unknowns by means of elementary algebraic operations. These two polynomials of multidegree two can be reduced to one univariate polynomial of degree four by means of resultants. The obtained quartic equation is solved analytically.

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The first analysis of inelastic J/{psi} meson production in photoproduction (Q{sup 2}<2.5 GeV{sup 2}) of the H1 experiment for the second phase of HERA (HERA II) is presented. The analysis is carried out at low and medium elasticities. The production of heavy quarks (charm, or bottom) is of special interest since the mass of the quarks provides a hard scale for the application of perturbative QCD. The muonic decay channel is used to select the J/{psi} mesons. The data was collected by the H1 detector during the period 2003-2005, and corresponds to an integrated luminosity of 133 pb{sup -1}. However only a subset of this data could be analysed. At the start of HERA II the trigger system was affected by a sizeable background. Then a fault was introduced in the trigger software during the summer 2004 and was only discovered and solved in April 2006. This means that approximately 80 % of the triggered events at medium elasticities and 65 % ...

International Nuclear Information System (INIS)

It is shown that account of nuclear effects in nucleon channel is of principle importance when analyzing hadron-nucleon process at high energies. This enables to make correct conclusions both about the contribution of multiquark systems - fluctons - to nuclear wave function and about quark distribution in them. Analysis of these distributions shows that color degrees of freedom in flucton are partially unfrozen and flucton contains with high probability one or two quarks.

International Nuclear Information System (INIS)

The K"+- and K"-meson cumulative production cross sections are measured at 119"0 in the laboratory system on nuclei Be, Al, Cu and Ta bombarded by 10 GeV protons. Spectra of the K"-mesons consisting of only sea quarks show universal features characteristic of the spectra of cumulative particles, which contain valence quarks. Evidence is obtained for the fact that the energy density in a flucton can exceed the mean nuclear density by an order of magnitude.

International Nuclear Information System (INIS)

The next-to-leading-order (NLO) cross section for the production of heavy quarks at large transverse momenta #gamma##gamma# collision is calculated with perturbative fragmentation functions (PFF). This approach allows for a resummation of terms #propor to# #alpha#_sln(p"2/m"2) which arise in NLO from collinear emission of gluons by a heavy quark at large p or from almost collinear branching of photons or gluons into heavy-quark pairs. It is presented single-inclusive distributions in p and rapidity including direct and resolved photons for #gamma##gamma# production of heavy quarks at e"+e"-colliders and at high-energy #gamma##gamma# colliders. The results are compared with fixed- order calculation for m finite including QDC radiative corrections. The two approaches differ in the definitions and relative contributions of the direct and resolved terms, but essentially agree in their sum. The resummation ...

CERN Document Server

In studying the dynamics of large N_c SU(N_c) gauge theory with fundamental quark flavours in the quenched approximation, we observe a novel phase transition at finite temperature. A quark condensate forms at finite quark mass, and the value of the condensate varies smoothly with the quark mass for generic region in parameter space. At a particular value of the quark mass, there is a finite discontinuity in the condensate's vacuum expectation value, corresponding to a first order phase transition. We study this using holography, the string dual being the geometry of N_c D3--branes at finite temperature, AdS_5-Schwarzschild times S^5, probed by a D7-brane. The D7-brane has topology R^4 times S^3 times S^1, and allowed solutions correspond to either the S^3 or the S^1 shrinking away in the interior of the geometry. The phase transition represents a jump between branches of solutions ...

International Nuclear Information System (INIS)

One of the most remarkable features of string theories is that they seem to provide a framework for a consistent theory of quantum gravity which is unified with all other forces. String theories fall into the two basic, a priori equally interesting, categories of open and closed string theories. For the past five years virtually all attention has been focused on purely closed string theories even though the reincarnation of string theory began with the discovery of anomaly cancellation and finiteness in the Green-Schwarz open superstring. It is the authors' purpose in this essay to rekindle interest in open string theories as potential theories of nature, including gravity. All string theories naively contain a massless dilaton which couples with the strength of gravity in direct violation of experiment. They present a simple mechanism for giving the dilaton a mass in unoriented open bosonic string theories.

CERN Document Server

During the last years, large-scale simulations of realistic physical environments which support the interaction of multiple participants over the Internet have become increasingly available and economically significant, most notably in the computer gaming industry. Such systems, commonly called networked virtual environments (NVEs), are usually based on a client-server architecture where for performance reasons and bandwidth restrictions, the simulation is partially deferred to the clients. This inevitable architectural choice renders the simulation vulnerable to attacks against the semantic integrity of the simulation: malicious clients may attempt to compromise the physical and logical laws governing the simulation, or to alter the causality of events a posteriori. In this paper, we initiate the systematic study of semantic integrity in NVEs from a security point of view. We argue that naive policies to enforce semantic integrity involve intolerable network load, ...

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The results of a search for fractionally charged particles produced in e/sup +/e/sup -/ annihilation at 29 GeV/c/sup 2/ are discussed. Results from cosmic-ray searches for fractionally charged particles, tachyons, and massive particles using the same detector are also presented.

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We study the large-Q{sup 2} behavior of the meson form factor F{sub M} (Q{sup 2}) constructed using the holographic light-front wave functions.

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The Alice experiment is one of the four main LHC (Large Hadron Collider) experiments. It is dedicated to the study of a new state of matter: the quark gluon plasma, where quarks and gluons are no longer confined within hadrons. In this document, the physics issues that led to the construction of Alice dimuon spectrometer, are described. Then, the research and development on the dimuon spectrometer is presented. The different absorbers are described and experimental tests used to determine their dimensions are presented. The dimuon trigger built using the RPC (Resistive Plate Chamber) streamer mode is then described along with the associated beam and cosmic tests and results. Finally, the tracking system is described in detail and more particularly all its electronics and the first station. The physics constraints on the expected performances of all these systems are clearly defined. (author)

CERN Document Server

We calculate quark-antiquark potentials using the relationship between the expectation value of the Wilson loop and the action of a probe string in the string dual. We review and categorize the possible forms of the dependence of the energy on the separation between the quarks. In particular, we examine the possibility of there being a minimum separation for probe strings which do not penetrate close to the origin of the bulk space, and derive a condition which determines whether this is the case. We then apply these considerations to the flavoured resolved deformed conifold background of Gaillard et al. We suggest that the unusual behaviour we observe in this solution is likely to be related to the IR singularity which is not present in the unflavoured case.

CERN Document Server

Heavy quark production in $\\gamma\\gamma$ collisions is analyzed within the approach to hard collisions of photons recently proposed by the author. In this approach evaluating the cross section $\\sigma(\\gamma\\gamma\\to Q\\bar{Q})$ in the ``next-to-leading order of QCD'' requires the inclusion of direct photon contributions up to the order $\\alpha^2\\alpha_s^2$, whereas in the standard approach direct photon terms only up to the order $\\alpha^2\\alpha_s$ are taken into account. Phenomenological consequences of this difference are discussed.

International Nuclear Information System (INIS)

A technique for calculation of the total weight of quark clusters-fluctons: in nuclei is developed. Blokhintsev's formula is justified microscopically and refined by introduction of spin-charge and quark factors. It is shown that the large values of the correlation radius (R/sub C/#approx =#0.75 fm or 1.0 fm) derived from experimental data in various papers using this formula correspond to #left brace#similarreverse arrowto#right brace#2.5 times smaller internucleon distances in the flucton (0.3--0.4 fm), i.e., the hardness of fluctons is caused by unsuppressed manifestation of hidden color at such distances (the corresponding probabilities are presented).

International Nuclear Information System (INIS)

In this paper, we study the J/#psi#(#UPSILON#) production in Z boson decay in a color-singlet model (CSM). We calculate the next-to-leading-order (NLO) QCD correction to Z#->#quarkonium+QQ, the dominant contribution in the CSM, with the vector and axial-vector parts in the ZQQ vertex being treated separately. The results show that the vector and axial-vector parts have the same K factor (the ratio of the NLO result to the leading-order result) 1.13 with the renormalization scale #mu#=2m_c and m_c=1.5 GeV, and the K factor falls to 0.918 when applying the Brodsky, Lepage, and Mackenzie (BLM) renormalization scale scheme with obtained #mu#_B_L_M=2.28 GeV and m_c=1.5 GeV. By including the contributions from the next-dominant ones, the photon and gluon fragmentation processes, the branching ratio for Z#->#J/#psi#_p_r_o_m_p_t+X is (7.3-10.0)x10"-"5 with the uncertainty consideration for the renormalization scale and charm quark mass. The ...

International Nuclear Information System (INIS)

We present results of an investigation to study CP violation in the Higgs sector in tt-bar production at a #gamma##gamma#-collider, via the process #gamma##gamma# #-># #phi# #-># tt-bar where the #phi# is a scalar with indeterminate CP parity. The study is performed in a model independent way parametrising the CP violating couplings in terms of six form factors #left brace#R(S_#gamma#), T(S_#gamma#), R(P_#gamma#), T(P_#gamma#), S_t, P_t#right brace#. The CP violation is reflected in the polarisation asymmetry of the produced top quark. We use the angular distribution of the decay lepton from t/t-bar as a diagnostic of this polarisation asymmetry and hence of the CP mixing, after showing that the asymmetries in the angular distribution are independent of any CP violation in the tbW vertex. We construct combined asymmetries in the initial state lepton (photon) polarization and the final state lepton charge and study how well different ...

International Nuclear Information System (INIS)

We investigate the possibility of kaon condensation in the dense interior of neutron stars through the s-wave interaction of kaons with nucleons. We include nucleon-nucleon interactions by using simple parametrizations of realistic forces, and include electrons and muons in #beta#-equilibrium. The equation of state above the condensate threshold is derived in the mean field approximation. The conditions under which kaon condensed cores undergo a transition to quark matter containing strange quarks are also established.The critical density for kaon condensation lies in the range (2.3-5.0)#rho#_0, where #rho#_0=0.16 fm"-"3 is the equilibrium density of nuclear matter. The critical density depends largely on the value of the strangeness content of the proton, the size of which is controversial. For too large a value of the strangeness content, matter with a kaon condensate is not sufficiently stiff to support the lower limit of 1.44 M_o_e_d_o_t ...

British Library Electronic Table of Contents (United Kingdom)

Men who have sex with men (MSM) have become one of the populations with severely HIV prevalence in China. However, very few genetic studies have been done on HIV-1 spreading in this population. In this study, the genetic characterization of HIV-1 strains prevalent in the MSM in Shijiazhuang, China, was analyzed basing on the HIV-1 full-length gag, pol, and partial env gene. 21 drug-naive HIV-1 sero-positive patients were enrolled into the study. Full length gag, pol, partial env genes and some near full length genomes were amplified with nest RT-PCR followed by sequencing. Multiple subtypes, including CRF01_AE (52.9%), subtype B (35.3%) and CRF07_BC (11.8%), were found in the population. Phylogenetic analysis showed close relationship between our strains with those from Beijing MSM but not...

DEFF Research Database (Denmark)

Purpose Cisplatin plus gemcitabine is a standard regimen for first-line treatment of advanced non-small-cell lung cancer (NSCLC). Phase II studies of pemetrexed plus platinum compounds have also shown activity in this setting. Patients and Methods This noninferiority, phase III, randomized study compared the overall survival between treatment arms using a fixed margin method (hazard ratio [HR] < 1.176) in 1,725 chemotherapy-naive patients with stage IIIB or IV NSCLC and an Eastern Cooperative Oncology Group performance status of 0 to 1. Patients received cisplatin 75 mg/m(2) on day 1 and gemcitabine 1,250 mg/m(2) on days 1 and 8 (n = 863) or cisplatin 75 mg/m(2) and pemetrexed 500 mg/m(2) on day 1 (n = 862) every 3 weeks for up to six cycles. Results Overall survival for cisplatin/pemetrexed was noninferior to cisplatin/ gemcitabine (median survival, 10.3 v 10.3 months, respectively; HR = 0.94; 95% CI, 0.84 to 1.05). Overall survival was statistically superior ...

International Nuclear Information System (INIS)

Using the constrained-curve fitting method and overlap fermions with the lowest pion mass at 180 MeV, we observe that the masses of the first positive and negative parity excited states of the nucleon tend to cross over as the quark masses are taken to the chiral limit. Both results at the physical pion mass agree with the experimental values of the Roper resonance (N"1"/"2"+(1440)) and S_1_1 (N"1"/"2"-(1535)). This is seen for the first time in a lattice QCD calculation. These results are obtained on a quenched Iwasaki 16"3x28 lattice with a=0.2 fm. We also extract the ghost #eta#"'N states (a quenched artifact) which are shown to decouple from the nucleon interpolation field above m_#pi##approx#300 MeV. From the quark mass dependence of these states in the chiral region, we conclude that spontaneously broken chiral symmetry dictates the dynamics of light quarks in the nucleon.

International Nuclear Information System (INIS)

Using the constrained curve fitting method and overlap fermions with the lowest pion mass at 180 MeV, we observe that the masses of the first positive and negative parity excited states of the nucleon tend to cross over as the quark masses are taken to the chiral limit. Both results at the physical pion mass agree with the experimental values of the Roper resonance (N"1"/"2"+ (1440)) and S_1_1 (N"1"/"2"-(1535)). This is seen for the first time in a lattice QCD calculation. These results are obtained on a quenched Iwasaki 16"3 x 28 lattice with a = 0.2 fm. We also extract the ghost #eta#(prime) N states (a quenched artifact) which are shown to decouple from the nucleon interpolation field above m_#pi# #approx# 300 MeV. From the quark mass dependence of these states in the chiral region, we conclude that spontaneously broken chiral symmetry dictates the dynamics of light quarks in the nucleon.

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Wonderful opportunities await particle physics over the next decade, with the coming of the Large Hadron Collider at CERN to explore the 1-TeV scale (extending efforts at LEP and the Tevatron to unravel the nature of electroweak symmetry breaking) and many initiatives to develop our understanding of the problem of identity: what makes a neutrino a neutrino and a top quark a top quark. Here I have in mind the work of the B factories and the Tevatron collider on CP violation and the weak interactions of the b quark; the wonderfully sensitive experiments at Brookhaven, CERN, Fermilab, and Frascati on CP violation and rare decays of kaons; the prospect of definitive accelerator experiments on neutrino oscillations and the nature of the neutrinos; and a host of new experiments on the sensitivity frontier. We might even learn to read experiment for clues about the dimensionality of spacetime. If we are inventive enough, we may be ...

CERN Document Server

Recently we discovered and discussed non-Abelian duality in the quark vacua of N=2 super-Yang-Mills theory with the U(N) gauge group and N_f flavors (N_f>N). Both theories from the dual pair support non-Abelian strings which confine monopoles. Now we introduce an N=2-breaking deformation, a mass term \\mu{\\mathcal A}^2 for the adjoint fields. Starting from a small deformation we eventually make it large which enforces complete decoupling of the adjoint fields. We show that the above non-Abelian duality fully survives in the limit of N=1 SQCD, albeit some technicalities change. For instance, non-Abelian strings which used to be BPS-saturated in the N=2 limit, cease to be saturated in N=1 SQCD. Our duality is a distant relative of Seiberg's duality in N=1 SQCD. Both share some common features but have drastic distinctions. This is due to the fact that Seiberg's duality apply to the monopole rather than quark vacua. More specifically, in our ...

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The high energy limit of Quantum Chromodynamics is one of the most fascinating areas in the theory of strong interactions. Over a decade ago the HERA experiment at DESY in Hamburg provided strong evidence for the rise of the proton structure function at small values of the Bjorken variable x. This behavior can be explained as an increase of the gluon density of the proton with energy or correspondingly with smaller values of x. This increase can be attributed on the other hand to the large probability of gluon splitting in QCD. The natural framework for describing the gluon dynamics at small x is the Balitskii-Fadin-Kuraev-Lipatov formalism developed some 30 years ago. It predicts that the gluon density grows very fast with increasing energy, as a power with a large intercept. This increase has to be tamed in order to satisfy the unitarily bound. Over two decades ago, Gribov, Levin and Ryskin proposed the mechanism called the parton saturation, which slows down the fast rise of the ...

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We present production rates of the two- and three-jet final states for the processes of massive cc/bb quark production in circularly polarized photon-photon collisions, including QCD radiative corrections. Lowest-order cross section, one-loop virtual correction, and gluon emission correction are shown to be of the same order of magnitude for bb quark production at s{sub {gamma}{gamma}} similar 100 GeV. It is shown that the signal from an intermediate mass Higgs boson is observable at a photon-photon collider, though the statistical significance is substantially reduced with respect to the tree-level calculation. ((orig.)).

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Possible anomalous top-quark couplings induced by SU(2)xU(1) gauge-invariant dimension-6 effective operators were studied in the process of ttbar productions and decays at polarized {gamma}{gamma} colliders. Two CP-violating asymmetries, a linear-polarization asymmetry and a circular-polarization asymmetry, were computed including both non-standard ttbar{gamma} and {gamma}{gamma}H couplings. An optimal-observable analysis for the process {gamma}{gamma}{yields}ttbar{yields}l{sup {+-}} was performed in order to estimate the precision for determination of all relevant non-standard couplings, including the anomalous tbW coupling.

International Nuclear Information System (INIS)

We perform an optimal-observable analysis of the final charged-lepton/b-quark momentum distributions in #gamma##gamma##->#t t-bar #->#lX/bX for various beam polarizations in order to study possible anomalous t t-bar #gamma#, tbW and #gamma##gamma#H couplings, which could be generated by SU(2) x U(1) gauge-invariant dimension-6 effective operators. We find optimal beam polarizations that will minimize the uncertainty in determination of those non-standard couplings. We also compare e e-bar and #gamma##gamma# colliders from the viewpoint of the anomalous-top-quark-coupling determination.

CERN Document Server

We calculate the quarkonium dissociation rate in the P and CP-odd domains (bubbles) that were possibly created in heavy-ion collisions. In the presence of the magnetic field produced by the valence quarks of colliding ions, parity-odd domains generate electric field. Quarkonium dissociation is the result of quantum tunneling of quark or antiquark through the potential barrier in this electric field. The strength of the electric field in the quarkonium comoving frame depends on the quarkonium velocity with respect to the background magnetic field. We investigate momentum, electric field strength and azimuthal dependence of the dissociation rate. Azimuthal distribution of quarkonia surviving in the electromagnetic field is strongly anisotropic; the form of anisotropy depends on the relation between the electric and magnetic fields and quarkonium momentum. These features can be used to explore the properties of the electromagnetic field created in ...

International Nuclear Information System (INIS)

A technique is developed for calculation of the total weight of the quark clusters-fluctons in atomic nuclei. The microscopical proof of Blochintsev formula is carried out and its refinement is obtained (spin-charge and quark factors enter the formula). It is shown that high values of the correlation radius (R_c #approx =# 0.75 fm or 1.0 fm in various papers) obtained from the experimental data making use of the above formula correspond to internucleon distances in flucton of 0.3-0.4 fm, which is by a factor of #approx# 2.5 lower. This means that the flucton hardness is due to free manifestation of hidden color at those distances (the appropriate probabilities are presented).

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

CERN Document Server

I report on a lattice computation of the energy of a system of two light quarks and two static antiquarks as a function of the separation of the static antiquarks. In terms of hadrons such a system corresponds to a pair of B mesons and its energy to the hadronic potential. I present selected results for different isospin, spin and parity combinations of the individual B mesons mainly focusing on those channels relevant to determine, whether two B mesons may form a bound tetraquark state.

International Nuclear Information System (INIS)

Based on a hypothesis of multiquark states in nuclei, the nucleus structure functions are considered and the results are compared with experiment. It is shown that the multiquark state contributions are sufficiently high (Up to 20% in deuterium and 40% in iron) and must possess a greater, than in a nucleon, sea of quark-antiquark pairs. Also the comparison with the cumulative particle production cross sections is performed. The predictions are given for a further experimental test of that hypothesis.

International Nuclear Information System (INIS)

We investigate the scope of all relevant production modes of charged Higgs bosons in the MSSM, with mass larger than the one of the top quark, at future Linear Colliders operating in #gamma##gamma# mode at the TeV energy scale. Final states with one or two H"#+-# bosons are considered, as produced by both tree- and loop-level interactions. (orig.)

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We present a measurement of the t{bar t} production cross section using events with one charged lepton and jets from p{bar p} collisions at a center-of-mass energy of 1.96TeV. In these events, heavy flavor quarks from top quark decay are identified with a secondary vertex tagging algorithm. From 162 pb{sup -1} of data collected by the Collider Detector at Fermilab, a total of 48 candidate events are selected, where 13.5 {+-} 1.8 events are expected from background contributions. We measure a t{bar t} production cross section of 5.6{sub -1.1}{sup _1.2}(stat.){sub -0.6}{sup +0.9}(syst.)pb.

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We study the a{sub 0} and {sigma} mesons with the overlap fermion in the chiral regime with the pion mass as low as 182 MeV in the quenched approximation. After the {eta} N ghost states are separated, we find that the a{sub 0} mass with q{bar q} interpolation field to be almost independent of the quark mass in the region below the strange quark mass. The chirally extrapolated results are consistent with a{sub 0}(1450) being the u{bar d} meson and K{sub 0}*(1430) being the u {bar s} meson. We also calculate the scalar mesonium with a tetraquark interpolation field. In addition to the two pion scattering states, we found a state at {approx} 550 MeV. Through the study of volume dependence, we confirm that this state is a one-particle state, in contrast to the two-pion scattering states. This suggests that the observed state is a tetraquark mesonium which is quite possibly the {sigma}(600) meson.

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Involvement of the dopaminergic system has been suggested in patients suffering from attention deficit hyperactivity disorder (ADHD) since the symptoms can be successfully treated with methylphenidate, a potent blocker of the dopamine transporter (DAT). This study reports the findings on the status of the DAT in adults with ADHD before and after commencement of treatment with methylphenidate, as measured using [{sup 99m}Tc]TRODAT-1. Seventeen patients (seven males, ten females, aged 21-64 years, mean 38 years) were examined before and after the initiation of methylphenidate treatment (3 x 5 mg/day). All subjects were injected with 800 MBq [{sup 99m}Tc]TRODAT-1 and imaged 3 h p.i. Single-photon emission tomography (SPET) scans were acquired using a triple-headed gamma camera. For semi-quantitative evaluation of the DAT, transverse slices corrected for attenuation were used to calculate specific binding in the striatum, with the cerebellum used as background [(STR-BKG)/BKG]. Data were ...

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Thomas Jefferson National Accelerator Facility experiment E01-012 measured the 3He spin structure functions and virtual photon asymmetries in the resonance region in the momentum transfer range 1.0 < Q2 < 4.0 (GeV/c)2. Our date, when compared with existing deep inelastic scattering data, can be used to test quark-hadron duality in g1 and A1 for 3He and the neutron. Preliminary results for A{sub 1}{sup {sup 3}He} are presented, as well as some details about the experiment.

International Nuclear Information System (INIS)

Three possibilities to observe the Higgs-top interaction at future #gamma##gamma#-colliders are discussed: a) associated Higss production via the #gamma##gamma##->#tanti tH reaction, b) Higgs obliged radiative correction to the #gamma##gamma##->#tanti t channel, c) Higgs resonance production via #gamma##gamma##->#H#->#ZZ. The results obtained show windows of the Higss mass where the Yukawa interaction of the Higss with the top quark can be studied at #gamma##gamma#-colliders. (orig.).

CERN Document Server

We show that in the Landau gauge of the SU(2) Yang-Mills theory the residual global symmetry supports existence of the topological vortices which resemble disclination defects in the nematic liquid crystals and the Alice (half-quantum) vortices in the superfluid heluim 3 in the A-phase. The theory also possesses half-integer and integer charged monopoles which are analogous to the point-like defects in the nematic crystal and in the liquid helium. We argue that the deconfinement phase transition in the Yang-Mills theory in the Landau gauge is associated with the proliferation of these vortices and/or monopoles. The disorder caused by these defects is suggested to be responsible for the confinement of quarks in the low-temperature phase.

International Nuclear Information System (INIS)

We present the efficient technique to extract the signal of the intermediate mass Higgs boson from the backgrounds at future #gamma##gamma# colliders. For a clear Higgs detection, it is important to fit the original electron accelerator energy depending on the Higgs mass, to set the polarization of the photon beams and to apply the efficient b quark tagging method. we demonstrate the extraction of information of Higgs parameters and the new physics from the observable physical quantities. It is clearly shown that a future #gamma##gamma# collider will have a rich potential for study on the new physics, as well as the Higgs physics. (author).

Energy Technology Data Exchange (ETDEWEB)

The authors discuss some of the results on the measurements of heavy flavor production at the Tevatron. Heavy flavor production can be used to test QCD over a wide range of quark masses (m{sub b} {approx} 4.5 GeV/c{sup 2} to m{sub t} = 174.3 {+-} 5.1 GeV/c{sup 2}). In addition, it is a background that has to be understood to perform physics measurements in the top sector and Higgs searches. The results reported here are performed using the Run1 data collected at Tevatron ({approx} 100 pb{sup -1}).

Energy Technology Data Exchange (ETDEWEB)

Most general tbW couplings were investigated in the process {gamma}{gamma} {yields} tt-bar {yields} l{sup {+-}}X for unpolarized photon beams. The double angular and energy distribution of the lepton was calculated and an optimal-observable analysis on it was carried out for the SM tt-bar production mechanism. It was also shown that the leptonic angular distribution is insensitive to non-standard tbW vertex. That means that observation of non-standard effects indicates existence of some new physics in the production part.

International Nuclear Information System (INIS)

The distributions of the effective numbers of 6q-fluctons in the energy, momentum and distance to the center of mass of nucleus are studied. Many characteristics of these distributions are shown to be universal, i.e. independent of the flucton size. The saturation of the flucton density in A > 80 nuclei and other peculiarities are found, which define different behavior of the effective numbers of fluctons and deuterons. This fact provides an explanation of the known underestimate by a factor of 1.5-6 of the cross sections of hard inclusive (p, p'd) process on nuclei calculated in the quasi-elastic approximation.

CERN Document Server

We review an analysis of a consistent renormalization of the top and bottom quark/squark sector of the MSSM with complex parameters (cMSSM). Various renormalization schemes are defined, analyzed analytically and tested numerically in the decays Stop_2 -> Sbottom_i H^+/W^+ (i = 1,2). No scheme is found that produces numerically acceptable results over all the cMSSM parameter space, where problems occur mostly already for real parameters. Some numerical examples for Gamma(Stop_2 -> Sbottom_1 H^+) in our preferred scheme, "m_b, A_b DRbar" are shown.

Science.gov (United States)

We present a high-statistics calculation of nucleon electromagnetic form factors in N{sub f}=2+1 lattice QCD using domain wall quarks on fine lattices, to attain a new level of precision in systematic and statistical errors. Our calculations use 32{sup 3}x64 lattices with lattice spacing a=0.084 fm for pion masses of 297, 355, and 403 MeV, and we perform an overdetermined analysis using on the order of 3600 to 7000 measurements to calculate nucleon electric and magnetic form factors up to Q{sup 2{approx_equal}}1.05 GeV{sup 2}. Results are shown to be consistent with those obtained using valence domain wall quarks with improved staggered sea quarks, and using coarse domain wall lattices. We determine the isovector Dirac radius r{sub 1}{sup v}, Pauli radius r{sub 2}{sup v} and anomalous magnetic moment {kappa}{sub v}. We also determine connected contributions to the corresponding isoscalar observables. We extrapolate these ...

Science.gov (United States)

The electromagnetic properties of the baryon decuplet are calculated in quenched QCD on a 20{sup 3}x40 lattice with a lattice spacing of 0.128 fm using the fat-link irrelevant clover fermion action with quark masses providing a pion mass as low as 300 MeV. Magnetic moments and charge radii are extracted from the electric and magnetic form factors for each individual quark sector. From these, the corresponding baryon properties are constructed. We present results for the higher-order moments of the spin-3/2 baryons, including the electric-quadrupole moment E2 and the magnetic-octupole moment M3. The world's first determination of a nonzero M3 form factor for the {delta} baryon is presented. With these results we provide a conclusive analysis which shows that decuplet baryons are deformed. We compare the decuplet-baryon results from a similar lattice calculation of the octet baryons. We establish that the environment sensitivity is far ...

CERN Document Server

Statistical modelling for social researchers

CERN Document Server

We discuss three possible ways to address quantum physics behind chiral magnetic effect and electric charge fluctuation patterns in heavy ion collisions. The first one makes use of P-parity violation probed by local order parameters, the second considers CME in quantum measurement theory framework and the third way is to study P-odd * P-odd contributions to P-even observables. In the latter approach relevant form-factor is extracted and computed for weak magnetic field in confinement region and for free quarks in strong field regime. It is shown that the effect is negligible in the former case. We also discuss saturation effect - charge fluctuation asymmetry for free fermions reaches constant value at asymptotically large fields.

Energy Technology Data Exchange (ETDEWEB)

Inclusive double spin asymmetries obtained by scattering polarized electrons off polarized protons and deuterons have been analyzed to address the issue of quark-hadron duality in the polarized spin structure functions g^p_1 and g^d_1. A polarized electron beam, solid polarized NH_3 and ND_3 targets and the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B were used to collect the data. The resulting g^p_1 and g^d_1 were averaged over the nucleon resonance energy region (M < W < 2.00 GeV), and three lowest lying resonances individually for tests of global and local duality.

British Library Electronic Table of Contents (United Kingdom)

MINER?A is a high resolution, fully active detector designed to study neutrino interactions on nuclei in the NuMI beam at Fermi National Accelerator Laboratory. The active volume of the detector consists of 3 tons of plastic scintillator and includes embedded targets of 4He, C, H2O, Fe and Pb. The MINER?A collaboration expects to perform precision, A-dependent neutrino cross section measurements in the 1?10 GeV region, measure the axial form factor, and study nuclear shadowing of F2, quark-hadron duality and coherent pion production, among other topics. MINER?A began data taking in the fall of 2009. This paper describes the MINER?A experiment and provides an overview of the physics objectives along with estimated uncertainties of the measurements and the tentative projected schedule of dat...

Energy Technology Data Exchange (ETDEWEB)

A large detector with high redundancy is used to search for various types of anomalous particles in cosmic rays at sea level. The detector is sensitive to zenith angles between 45/sup 0/ and 90/sup 0/. Previously obtained limits on the fluxes of charge (1/3) and (2/3) particles are reduced to 2.9 x 10/sup -10/ and 2.6 x 10/sup -10/ cm/sup -2/sr /sup -1/ sec/sup -1/, respectively. The flux of ionizing tachyons is determined to be less than 2.4 x 10/sup -9/ cm/sup -2/ sr/sup -1/ sec/sup -1/. The massive-particle flux limit we obtain is inconsistent with previous claims of such particles assuming that these particles are isotropic in zenith angle.

International Nuclear Information System (INIS)

The exclusive electroproduction of ?0 mesons was studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. Spin density matrix elements for this process were determined from the measured production- and decay-angle distributions of the produced ?0 mesons. These matrix elements embody information on helicity transfer and the validity of s-channel helicity conservation in the case of a transversely polarized target. From the spin density matrix elements, the leading-twist term in the single-spin asymmetry was calculated separately for longitudinally and transversely polarized ?0 mesons. Neglecting s-channel helicity changing matrix elements, results for the former can be compared to calculations based on generalized parton distributions, which are sensitive to the contribution of the total angular momentum of the quarks to the proton spin.

Energy Technology Data Exchange (ETDEWEB)

The energy, angular momentum, and distance (measured from the center of mass of the nucleus) distributions of the effective number of 6/ital q/-fluctons are investigated and it is shown that many of the characteristics of these distributions are universal, i.e., independent of the flucton size. ''Saturation'' of the flucton density in nuclei with mass /ital A//approx gt/80 and certain other features that determine the difference between the behaviors of the effective numbers of fluctons and deuterons are reported. This is used to explain the well known underestimation (by a factor of 1.5--6) of the cross section for the hard inclusive (/ital p/, /ital p/'/ital d/) process on nuclei calculated in the quasielastic formalism. See S. G. Kadmenskii and V. I. Furman, /ital Alpha/ /ital decay/ /ital and elated/ /ital nuclear/ /reactions/ (in Russian), Energoatomizdat, Moscow, 1985.

CERN Document Server

We present an update of the most stringent experimental bounds on the trilinear R-parity violating couplings. We then analyse bounds on the R-parity violating couplings at the unification scale by renormalising the weak scale bounds. We derive unification scale upper bounds upon the couplings which are broadly independent of the fermion mass texture assumed. The R-parity violating couplings are factors of two to five more severely bounded at the unification scale than at the electroweak scale. In the presence of quark mixing, a few of the bounds are orders of magnitude stronger than their weak scale counterparts due to new R-parity violating operators being induced in the renormalisation between high and low scales. These induced bounds are fermion mass texture dependent. New bounds upon the weak scale couplings are obtained by the requirement of perturbativity between the weak and unification scales. A comprehensive set of the latest limits is included.

Energy Technology Data Exchange (ETDEWEB)

I describe a search for anomalous production of Z pairs through a new massive resonance X in 2.5-2.9 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV using the CDFII Detector at the Fermilab Tevatron. I reconstruct Z pairs through their decays to electrons, muons, and quarks. To achieve perhaps the most efficient lepton reconstruction ever used at CDF, I apply a thorough understanding of the detector and new reconstruction software heavily revised for this purpose. In particular, I have designed and employ new general-purpose algorithms for tracking at large {eta} in order to increase muon acceptance. Upon analyzing the unblinded signal samples, I observe no X {yields} ZZ candidates and set upper limits on the production cross section using a Kaluza-Klein graviton-like acceptance.

UK PubMed Central (United Kingdom)

SIMV (simulation and modeling of ventilation) is a quantitative system for the mathematical modeling and simulation of pulmonary...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Science.gov (United States)

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Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

ScienceCinema

...english ...

Science.gov (United States)

... Multivibrators were used in the first model, which is called the "MV Model." Mwe second model, "1ST Model," has a saw-toothed voltage. ...

Energy Technology Data Exchange (ETDEWEB)

New measurements of the spin structure functions of the proton and deuteron g{sub 1}{sup p}(x, Q{sup 2}) and g{sub 1}{sup d}(x, Q{sup 2}) in the nucleon resonance region are compared with extrapolations of target-mass-corrected next-to-leading-order (NLO) QCD fits to higher energy data. Averaged over the entire resonance region (W < 2 GeV), the data and QCD fits are in good agreement in both magnitude and Q{sup 2} dependence for Q{sup 2} > 1.7 GeV{sup 2}/c{sup 2}. This ''global'' duality appears to result from cancellations among the prominent ''local'' resonance regions: in particular strong {sigma}{sub 3/2} contributions in the {Delta}(1232) region appear to be compensated by strong {sigma}{sub 1/2} contributions in the resonance region centered on 1.5 GeV. These results are encouraging for the extension of NLO QCD fits to lower W and Q{sup 2} than have been used previously.

Science.gov (United States)

Semi-inclusive pi+ electroproduction on protons has been measured with the CLAS detector at Jefferson Lab. The measurement was performed on a liquid-hydrogen target using a 5.75 GeV electron beam. The complete five-fold differential cross sections were measured over a wide kinematic range in Q2, x, z, and pT and over the complete range of azimuthal angles, phi, enabling us to separate the different structure functions, H2+eps*H1, H3 and H4. Our measurements of H2 at low-x were found to be in fairly good agreement with pQCD calculations, suggesting a precocious factorization of the process. Indeed, the conventional f(x)*D(z) term can account for almost all of the observed cross section, even at small z. The measured xF-distributions are in qualitative agreement with high energy data, which suggests a surprising numerical similarity between the spectator diquark fragmentation in the present reaction and the anti-quark fragmentation measured in e+e- collisions. We ...

CERN Document Server

This paper studies the way in which confinement leads to chiral symmetry breaking (CSB) through a gap equation. We argue that entropic effects cut off infrared singularities in the standard confining effective propagator $1/p^4$, which should be replaced by $1/(p^2+m^2)^2$ for a finite mass $m\\sim K_F/M(0)$ [$M(0)$ is the zero-momentum value of the running quark mass]. Extension of an old calculation of the author yields a specific estimate for $m$. This cutoff propagator shows semi-quantitatively two critical properties of confinement: 1) a negative contribution to the confining potential coming from entropic forces; 2) an infrared cutoff required by gauge invariance and CSB itself. Entropic effects lead to a proliferation of pion branches and a $\\bar{q}q$ condensate, and contribute a negative term $\\sim -K_F/M(0)$ to the effective pion Hamiltonian allowing for a massless pion in the presence of positive kinetic energy and string energy. The resulting gap ...

Science.gov (United States)

... 4 Joint Committee on Atomic Energy as a Model . . . . . ... Joint Committee on Atomic Energy as a Model ...

Wastenet

Institutional and organizational models ... Review individual centre institutional and organizational models in the light of the tasks to be performed by

Energy Technology Data Exchange (ETDEWEB)

The role of natural enemies in the regulation of populations is one of the major questions facing population ecologists. Simplification have led to two theoretical ways of incorporating the role of natural enemies in single ecological models: diffusion models and patch-type models. The predictions of the models are different because of the way variability is incorporated. Three equations are presented for diffusion models and one for patch models. Since the two types of models apply at different combinations of spatial and temporal scales, the right model(s) to choose for a particular study requires careful assessment. A continuing dialogue between experimentalists and theoreticians will lead to a better understanding of natural systems such as those that occur in biological control.

Science.gov (United States)

terms of 11) numerical models, 2D SPH simulations, and analytic models. The 1D model was useful for determining the evolution over very long timescales. ...

UK PubMed Central (United Kingdom)

Models can be useful at many different levels when considering complex issues such as biological control of mosquitoes. At an early stage, exploratory models are valuable in exploring the characteristics...Full Text Available

Science.gov (United States)

Engine model: An engine and governor model adapted from a heavy lift helicopter simulation provides a restistic time delay between aerodynamic rotor ...

CERN Document Server

The Inner Model Hypothesis (IMH) and the Strong Inner Model Hypothesis (SIMH) were introduced by the first author in ``Internal consistency and the inner model hypothesis'', Bulletin of Symbolic Logic, December 2006. In this article we establish some upper and lower bounds for their consistency strength.

Science.gov (United States)

This 1978 annual report contains the results of ''Seismic testing of Wolsung-1 steam generator model'' which was initiated in 1977 as a part of a study on nuclear components testing. Model 78, improved version of Model 77 which did not take into account f...

KoreaScience (Korea)

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Science.gov (United States)

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CERN Document Server

Multiphase reacting flows

Energy Technology Data Exchange (ETDEWEB)

No abstract available.

Norwegian Open Research Archives (NORA)

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KoreaScience (Korea)

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Norwegian Open Research Archives (NORA)

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Czech Academy of Sciences Repository

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Energy Technology Data Exchange (ETDEWEB)

In recent years the modelling of interannual climate variability has been studied, the atmospheric energy and water cycles, and climate simulations with the ECHAM3 model. In addition, the climate simulations of several models have been compared with special emphasis in the area of northern Europe

Norwegian Open Research Archives (NORA)

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KoreaScience (Korea)

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Science.gov (United States)

processes, we construct a stochastic dynamic model for air- craft counts in ... Also , queueing models for the arrival of aircraft at ... A queueing model has also been used to study ...... Assignment and Aircraft-Sequencing Algorithms in Terminal ...

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

This paper presents research work concerning the mathematical modelling of air pollution in the Athens basin. A mathematical model based on aerodynamics and conservation equations together with turbulence modelling in body-fitted coordinates is used to provide the necessary input information to a similar but more detailed (i.e. small scale) model around Athens. Both models consist of solving the full Navier-Stokes equations and take into account the precise topography of the region. Different roughness heights are used for sea, coastal regions and land. The smaller scale model makes use of a two-equation turbulence model ({kappa}-{epsilon}) and the large scale model assumes a constant turbulence viscosity. The pollutant sources used in these models are based on actual emissions in the Athens area and ...

CERN Document Server

This paper presents a model of the dynamics of the wage income distribution.

Science.gov (United States)

... 1]. Results and Discussion A cross section of liquid feed direct borohydride fuel cell model was created and studied. The ...

Science.gov (United States)

... Lincoln Laboratory Distribution Models for Optical Scintillation Due to Atmospheric Turbulence RR Parenti RJ Susiela Group 107 ...

Energy Technology Data Exchange (ETDEWEB)

Non-linear autoregressive Markov regime-switching models are intuitive. Time-series approaches for the modelling of electricity spot prices are frequently proposed. In this paper, such models are compared with an ordinary linear autoregressive model with regard to their forecast performances. The study is carried out using German daily spot-prices from the European Energy Exchange in Leipzig. Four non-linear models are used for the forecast study. The results of the study suggest that Markov regime-switching models provide better forecasts than linear models. (author)

Science.gov (United States)

... 3 Joint Committee on Atomic Energy as a Model . . . . . ... Joint Committee on Atomic Energy as a Model Page 8. CRS-4 ...

CERN Document Server

The concept of frailty offers a convenient way to introduce unobserved heterogeneity and associations into models for survival data. In its simplest form, frailty is an unobserved random proportionality factor that modifies the hazard function of an individual or a group of related individuals. "Frailty Models in Survival Analysis" presents a comprehensive overview of the fundamental approaches in the area of frailty models. The book extensively explores how univariate frailty models can represent unobserved heterogeneity. It also emphasizes correlated frailty models as extensions of

CERN Document Server

This paper proposes the use of particle swarm optimization method (PSO) for finite element (FE) model updating. The PSO method is compared to the existing methods that use simulated annealing (SA) or genetic algorithms (GA) for FE model for model updating. The proposed method is tested on an unsymmetrical H-shaped structure. It is observed that the proposed method gives updated natural frequencies the most accurate and followed by those given by an updated model that was obtained using the GA and a full FE model. It is also observed that the proposed method gives updated mode shapes that are best correlated to the measured ones, followed by those given by an updated model that was obtained using the SA and a full FE model. Furthermore, it is observed that the PSO achieves this accuracy at a computational speed that is faster than that by the ...

Energy Technology Data Exchange (ETDEWEB)

A detailed component-based simulation model of a geothermal heat pump system has been calibrated to monitored data taken from a family housing unit located at Fort Polk, Louisiana. The simulation model represents the housing unit, geothermal heat pump, ground heat exchanger, thermostat, blower, and ground-loop pump. Each of these component models was tuned to better match the measured data from the site. These tuned models were then interconnected to form the system model. The system model was then exercised in order to demonstrate its capabilities.

British Library Electronic Table of Contents (United Kingdom)

This paper introduces a new way of estimating parameters in a Brownian motion regime switching asset model to incorporate volatility clustering. The regime switching model is then applied to pricing of up-and-in barrier call options. We take the probability of crossing the barrier between simulation points into account, and we increase accuracy in simulations by importance sampling. The regime switching model is compared to the Normal Inverse Gaussian model and the traditional Black-Scholes model, and option prices from the regime switching model are compared to the closed form expression of up-and-in barrier calls in a Black-Scholes market.

International Nuclear Information System (INIS)

An integrated approach to the modelling of hydrogen assisted failure in 316L steel is presented. The approach includes experimental, fractographic, numerical and theoretical analysis of the phenomenon. The physical adequacy of the mechanical models of hydrogen embrittlement (notch extension model and notch cracking model) is discussed by comparing the virtual damage depth (theoretical) predicted by the models with the embrittled zone (microphysical) measured in the fractographic analysis by scanning electron microscopy. In addition, a numerical modelling of hydrogen diffusion is performed, concluding that bulk diffusion is not important in hydrogen embrittlement of 316L steel, so that hydrogen transport accelerated by the microdamage itself should be taken into account. (orig.)

International Nuclear Information System (INIS)

Higgs mediated flavor violating electromagnetic interactions, induced at the one-loop level by a nondiagonal Hf_if_j vertex, with f_i and f_j charged leptons or quarks, are studied within the context of a completely general effective Yukawa sector that comprises SU_L(2)xU_Y(1)-invariant operators of up to dimension-six. Exact formulae for the one-loop #gamma#f_if_j and #gamma##gamma#f_if_j couplings are presented and their related processes used to study the phenomena of Higgs mediated lepton flavor violation. The experimental limit on the #mu##->#e#gamma# decay is used to derive a bound on the branching ratio of the #mu##->#e#gamma##gamma# transition, which is 6 orders of magnitude stronger than the current experimental limit. Previous results on the #tau##->##mu##gamma# and #tau##->##mu##gamma##gamma# decays are reproduced. The possibility of detecting signals of lepton flavor violation at #gamma##gamma# colliders is explored through the ...

Energy Technology Data Exchange (ETDEWEB)

The constitutive model used to describe the deformation of crushed salt is presented in this report. Two mechanisms -- dislocation creep and grain boundary diffusional pressure solution -- are combined to form the basis for the constitutive model governing the deformation of crushed salt. The constitutive model is generalized to represent three-dimensional states of stress. Upon complete consolidation, the crushed-salt model reproduces the Multimechanism Deformation (M-D) model typically used for the Waste Isolation Pilot Plant (WIPP) host geological formation salt. New shear consolidation tests are combined with an existing database that includes hydrostatic consolidation and shear consolidation tests conducted on WIPP and southeastern New Mexico salt. Nonlinear least-squares model fitting to the database produced two sets of material parameter values for the ...

Science.gov (United States)

The objective of this Task Group is the coordination of research studies on biokinetic models and the evaluation of the implications of new biokinetic models on dose assessment and safety standards. For this the new ICRP models, which will be used for a revision of ICRP Publications 30, 54, 68 and 78, are implemented into six different computer codes in five European countries and quality assured by intercomparison procedures. The work has started with the implementation of the new ICRP Alimentary Tract Model. New systemic models and the new NCRP wound model will follow. The work also includes the evaluation of experimental results in terms of formulation by the new model structures and a quality assurance of model formulation. PMID:17556343

Energy Technology Data Exchange (ETDEWEB)

The heat capacity and heat of fusion were measured for a number of minerals using differential scanning calorimetry (DSC). The DSC measurements showed that the heat of fusion for the minerals is very low compared to the heat of fusion for pure crystalline phases reported elsewhere. A model for the melting behaviour of mineral materials in terms of melting interval, heat capacities and heat of fusion has been developed. The only model input is the chemical composition of the mineral material. The model was developed to be implemented in a detailed model of a cupola furnace, thus the focus for the development was not only precision but also to obtain a model that was continuous and differentiable. The model is based on several different submodels that each covers a part of the heating and melting of rocks. Each submodel is based on large amounts of empirical data. ...

International Nuclear Information System (INIS)

The high-power model of Disk-and Washer (DAW) cavity for electron acceleration is under fabrication. Basic Dimensions of the cavity were determined from aluminum model measurement and electromagnetic field calculation. We have fabricated model made of OFC (Oxygen Free Copper) five times in total. Some details are optimized and corrected, and then the final brazing are proceeding. These model results and present status are described. (author)

Energy Technology Data Exchange (ETDEWEB)

This report to the Nuclear Regulatory Commission (NRC) describes the development and application of a methodology to systematically and quantitatively assess predictive uncertainty in groundwater flow and transport modeling that considers the combined impact of hydrogeologic uncertainties associated with the conceptual-mathematical basis of a model, model parameters, and the scenario to which the model is applied. The methodology is based on a n extension of a Maximum Likelihood implementation of Bayesian Model Averaging. Model uncertainty is represented by postulating a discrete set of alternative conceptual models for a site with associated prior model probabilities that reflect a belief about the relative plausibility of each model based on its apparent consistency with available knowledge and ...

Science.gov (United States)

This paper presents a case study in the design and implementation of a numerical weather prediction model on a supercomputer (CRAY-1). Following a historical introduction to the evolution of the model, the governing equations of the model are presented and the numerical solution of these forecast equations is described. A brief tutorial on the architecture of the CRAY-1 is presented with a discussion of how it affects the choice of algorithms and code design of the model. A summary of the advantages gained by use of the vector aspects of the CRAY-1 is included.

UK PubMed Central (United Kingdom)

The brain maintains internal models of its environment to interpret sensory inputs and prepare actions. While behavioral studies demonstrated that these internal models are optimally adapted...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

We obtain a symmetry algebra for any unitary minimal model by using the representation of conformal field theories. This symmetry algebra can be interpreted as a quantum group. The generalization to non-unitary minimal models is direct. (orig.).

UK PubMed Central (United Kingdom)

BackgroundLiquid chromatography-mass spectrometry (LC-MS) is one of the major techniques for the quantification of metabolites in complex biological samples. Peak modeling is one...Full Text Available

Science.gov (United States)

In this paper two different models of brain regulation of exercise performance are critically compared: the central governor model proposed by Noakes and colleagues, and an alternative psycholobiological model based on motivational intensity theory. PMID:18618133

International Nuclear Information System (INIS)

We show the existence of a rather general class of closed cosmological models of Bianchi type IX that do not exhibit recollapse but expand for all times. This is despite the fact that these models satisfy the strong energy condition by a wide margin.

UK PubMed Central (United Kingdom)

We present the formulation and testing of a mathematical model for the kinetics of homotypic cellular aggregation. The model considers cellular aggregation under no-flow conditions as a two-step process....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Volume VII of the documentation for the Phase I Data Analysis Task performed in support of the current Regional Flow Model, Transport Model, and Risk Assessment for the Nevada Test Site Underground Test Area Subproject contains the tritium transport model documentation. Because of the size and complexity of the model area, a considerable quantity of data was collected and analyzed in support of the modeling efforts. The data analysis task was consequently broken into eight subtasks, and descriptions of each subtask's activities are contained in one of the eight volumes that comprise the Phase I Data Analysis Documentation.

Energy Technology Data Exchange (ETDEWEB)

;Contents: Comparison of Simulation Modules of TRANSYT and INTEGRATION Models; Evaluation of SCATSIM-RTA Adaptive Traffic Network Simulation Model; Comparison NETSIM, NETFLO I, and NETFLO II Traffic Simulation Models for Fixed-Time Signal Control; Traffic Flow Simulation Through Parallel Processing; Cluster Analysis as Tool in Traffic Engineering; Traffic Platoon Dispersion Modeling on Arterial Streets; Hybrid Model for Estimating Permitted Left-Turn Saturations Flow Rate; and Passing Sight Distance and Overtaking Dilemma on Two-Lane Roads.

Energy Technology Data Exchange (ETDEWEB)

We discuss the asymptotic dynamical evolution of spatially homogeneous brane-world cosmological models close to the initial singularity. We find that generically the cosmological singularity is isotropic in Bianchi type IX brane-world models and consequently these models do not exhibit Mixmaster or chaotic-like behaviour close to the initial singularity. We argue that this is typical of more general cosmological models in the brane-world scenario. In particular, we show that an isotropic singularity is a past-attractor in all orthogonal Bianchi models and is a local past-attractor in a class of inhomogeneous brane-world models. (letter to the editor)

International Nuclear Information System (INIS)

In this paper extended models for estimating price developments on electricity markets are presented. The models consider deviations from the normality hypothesis of the prices. Based on an ARMA model combination with GARCH, Gaussian-mixture and switching-regime approaches are comparatively discussed. The comparison is based on historic electricity prices of the spot and two reserve markets in Germany. It is shown that the proposed extended models lead to significantly improved representations of the considered stochastic price processes. It is inferred that these models may be preferred for estimating price developments on electricity markets. (author)

Science.gov (United States)

Models are proposed which explain the mechanism of action on a molecular level for the initiation of cancer by electrons or alpha particles. (ACR)

International Nuclear Information System (INIS)

A review is made of some recent developments in the application of the Bohr Hamiltonian to transitional nulcei. The primary concern is to understand the advantages and limitations inherent to the basic model and its many variants. (author).

Energy Technology Data Exchange (ETDEWEB)

We argue that the tachyons which exist in some string models are a signal of deconfinement. We compare the deconfinement temperature obtained from Monte Carlo calculations with some string models. (orig.).

Science.gov (United States)

... kinematic model for the robots and designed ... theoretic approach for modeling mobile robot teamn formations". ... "UUV teams, control from a biological ...

UK PubMed Central (United Kingdom)

BackgroundPreclinical models of pediatric cancers are essential for testing new chemotherapeutic combinations for clinical trials. The most widely used ...Full Text Available

Science.gov (United States)

... Those functions are fundamental routines to build a power model for more complex circuits or functional blocks. ... 21 of 54 6. Memory Power Model ...

Energy Technology Data Exchange (ETDEWEB)

This dissertation is devoted to the study of the phenomenological consequences of the three-generation heterotic string models based on the Calabi-Yau compactifications and the N = 2 superconformal constructions.

Science.gov (United States)

Sep 1, 2011 ... 2005. Computer simulation modeling of recreation use: current status, case studies, and future directions. Gen. Tech. Rep. RMRS-GTR-143. ...

Science.gov (United States)

Hemez9 on the Predictive Capability Maturity Model, and for their feedback on the CAS d uring a 2 007 technical interchange meeting in Albuquerque, NM. ...