The hadronic standard model for strong and electroweak interactions

International Nuclear Information System (INIS)

Raczka, R.

1993-01-01

We propose a new model for strong and electro-weak interactions. First, we review various QCD predictions for hadron-hadron and lepton-hadron processes. We indicate that the present formulation of strong interactions in the frame work of Quantum Chromodynamics encounters serious conceptual and numerical difficulties in a reliable description of hadron-hadron and lepton-hadron interactions. Next we propose to replace the strong sector of Standard Model based on unobserved quarks and gluons by the strong sector based on the set of the observed baryons and mesons determined by the spontaneously broken SU(6) gauge field theory model. We analyse various properties of this model such as asymptotic freedom, Reggeization of gauge bosons and fundamental fermions, baryon-baryon and meson-baryon high energy scattering, generation of Λ-polarization in inclusive processes and others. Finally we extend this model by electro-weak sector. We demonstrate a remarkable lepton and hadron anomaly cancellation and we analyse a series of important lepton-hadron and hadron-hadron processes such as e + + e - → hadrons, e + + e - → W + + W - , e + + e - → p + anti-p, e + p → e + p and p + anti-p → p + anti-p processes. We obtained a series of interesting new predictions in this model especially for processes with polarized particles. We estimated the value of the strong coupling constant α(M z ) and we predicted the top baryon mass M Λ t ≅ 240 GeV. Since in our model the proton, neutron, Λ-particles, vector mesons like ρ, ω, φ, J/ψ ect. and leptons are elementary most of experimentally analysed lepton-hadron and hadron-hadron processes in LEP1, LEP2, LEAR, HERA, HERMES, LHC and SSC experiments may be relatively easily analysed in our model. (author). 252 refs, 65 figs, 1 tab

The hadronic standard model for strong and electroweak interactions

Energy Technology Data Exchange (ETDEWEB)

Raczka, R [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)

1994-12-31

We propose a new model for strong and electro-weak interactions. First, we review various QCD predictions for hadron-hadron and lepton-hadron processes. We indicate that the present formulation of strong interactions in the frame work of Quantum Chromodynamics encounters serious conceptual and numerical difficulties in a reliable description of hadron-hadron and lepton-hadron interactions. Next we propose to replace the strong sector of Standard Model based on unobserved quarks and gluons by the strong sector based on the set of the observed baryons and mesons determined by the spontaneously broken SU(6) gauge field theory model. We analyse various properties of this model such as asymptotic freedom, Reggeization of gauge bosons and fundamental fermions, baryon-baryon and meson-baryon high energy scattering, generation of {Lambda}-polarization in inclusive processes and others. Finally we extend this model by electro-weak sector. We demonstrate a remarkable lepton and hadron anomaly cancellation and we analyse a series of important lepton-hadron and hadron-hadron processes such as e{sup +} + e{sup -} {yields} hadrons, e{sup +} + e{sup -} {yields} W{sup +} + W{sup -}, e{sup +} + e{sup -} {yields} p + anti-p, e + p {yields} e + p and p + anti-p {yields} p + anti-p processes. We obtained a series of interesting new predictions in this model especially for processes with polarized particles. We estimated the value of the strong coupling constant {alpha}(M{sub z}) and we predicted the top baryon mass M{sub {Lambda}{sub t}} {approx_equal} 240 GeV. Since in our model the proton, neutron, {Lambda}-particles, vector mesons like {rho}, {omega}, {phi}, J/{psi} ect. and leptons are elementary most of experimentally analysed lepton-hadron and hadron-hadron processes in LEP1, LEP2, LEAR, HERA, HERMES, LHC and SSC experiments may be relatively easily analysed in our model. (author). 252 refs, 65 figs, 1 tab.

Quark confinement and hadronic interactions

International Nuclear Information System (INIS)

Lenz, F.

1985-01-01

With the possibility for 'exact' calculations within the framework of a fundamental theory, QCD, the role of models in strong interaction physics is changing radically. The relevance of detailed numerical model studies is diminishing with the development of those exact, numerical approaches to QCD. On the other hand, the insight gained from such purely numerical studies is necessarily limited and must be complemented by the more qualitative but also more intuitive insight gained from model studies. In particular, the subject of hadron-hadron interactions requires model studies to relate the wide variety of strong interaction physics to the fundamental properties of strong interaction physics. The author reports on such model studies of the hadron-hadron interaction

Strangeness production in hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions in the dual parton model

International Nuclear Information System (INIS)

Moehring, H.; Ranft, J.; Capella, A.; Tran Thanh Van, J.

1993-01-01

Λ, bar Λ, and K S 0 production is studied in a Monte Carlo dual parton model for hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions with an SU(3) symmetric sea for chain formation (chain ends) but strangeness suppression in the chain fragmentation process. Additionally, (qq)-(bar q bar q) production from the sea was introduced into the chain formation process with the same probability as for the q→qq branching within the chain decay process. With these assumptions, multiplicity ratios and Feynman-x distributions for strange particles in h-h and multiplicity ratios in heavy ion collisions are reasonably well reproduced

Heavy flavor at the large hadron collider in a strong coupling approach

Energy Technology Data Exchange (ETDEWEB)

He, Min [Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094 (China); Fries, Rainer J.; Rapp, Ralf [Cyclotron Institute and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843-3366 (United States)

2014-07-30

Employing nonperturbative transport coefficients for heavy-flavor (HF) diffusion through quark–gluon plasma (QGP), hadronization and hadronic matter, we compute D- and B-meson observables in Pb+Pb (√(s)=2.76 TeV) collisions at the LHC. Elastic heavy-quark scattering in the QGP is evaluated within a thermodynamic T-matrix approach, generating resonances close to the critical temperature which are utilized for recombination into D and B mesons, followed by hadronic diffusion using effective hadronic scattering amplitudes. The transport coefficients are implemented via Fokker–Planck Langevin dynamics within hydrodynamic simulations of the bulk medium in nuclear collisions. The hydro expansion is quantitatively constrained by transverse-momentum spectra and elliptic flow of light hadrons. Our approach thus incorporates the paradigm of a strongly coupled medium in both bulk and HF dynamics throughout the thermal evolution of the system. At low and intermediate p{sub T}, HF observables at LHC are reasonably well accounted for, while discrepancies at high p{sub T} are indicative for radiative mechanisms not included in our approach.

HERWIG for Hadron-Hadron physics

International Nuclear Information System (INIS)

Seymour, M.H.

1993-05-01

HERWIG is a general-purpose particle physics event generator, which includes the simulation of any combination of hard lepton, hadron or photon scattering and soft hadron-hadron collisions in one package. It uses the parton-shower approach for initial-state and final-state QCD radiation, including colour coherence effects and azimuthal correlations both within and between jets. This article describes HERWIG version 5.6, and gives a brief review of the physics underlying HERWIG, with particular emphasis on hadron-hadron collisions. Details are given of the input and control parameters used by the program

Statistical Hadronization and Holography

DEFF Research Database (Denmark)

Bechi, Jacopo

2009-01-01

In this paper we consider some issues about the statistical model of the hadronization in a holographic approach. We introduce a Rindler like horizon in the bulk and we understand the string breaking as a tunneling event under this horizon. We calculate the hadron spectrum and we get a thermal...

Relativistic form factors for hadrons with quark-model wave functions

International Nuclear Information System (INIS)

Stanley, D.P.; Robson, D.

1982-01-01

The relationship between relativistic form factors and quark-potential-model wave functions is examined using an improved version of an approach by Licht and Pagnamenta. Lorentz-contraction effects are expressed in terms of an effective hadron mass which varies as the square root of the number of quark constituents. The effective mass is calculated using the rest-frame wave functions from the mean-square momentum along the direction of the momentum transfer. Applications with the parameter-free approach are made to the elastic form factors of the pion, proton, and neutron using a Hamiltonian which simultaneously describes mesons and baryons. A comparison of the calculated radii for pions and kaons suggests that the measured kaon radius should be slightly smaller than the corresponding pion radius. The large negative squared charge radius for the neutron is partially explained via the quark model but a full description requires the inclusion of a small component of a pion ''cloud'' configuration. The problematic connection between the sizes of hadrons deduced from form factors and the ''measured'' values of average transverse momenta is reconciled in the present model

Confinement and hadron-hadron interactions by general relativistic methods

Science.gov (United States)

Recami, Erasmo

By postulating covariance of physical laws under global dilations, one can describe gravitational and strong interactions in a unified way. Namely, in terms of the new discrete dilational degree of freedom, our cosmos and hadrons can be regarded as finite, similar systems. And a discrete hierarchy of finite ``universes'' may be defined, which are governed by fields with strengths inversally proportional to their radii; in each universe an Equivalence Principle holds, so that the relevant field can be there geometrized. Scaled-down Einstein equations -with cosmological term- are assumed to hold inside hadrons (= strong micro-cosmoses); and they yield in a natural way classical confinement, as well as ``asymptotic freedom'', of the hadron constituents. In other words, the association of strong micro-universes of Friedmann type with hadrons (i.e., applying the methods of General Relativity to subnuclear particle physics) allows avoiding recourse to phenomenological models such as the Bag Model. Inside hadrons we have to deal with a tensorial field (= strong gravity), and hadron constituents are supposed to exchange spin-2 ``gluons''. Our approach allows us also to write down a tensorial, bi-scale field theory of hadron-hadron interactions, based on modified Einstein-type equations here proposed for strong interactions in our space. We obtain in particular: (i) the correct Yukawa behaviour of the strong scalar potential at the static limit and for r>~l fm; (ii) the value of hadron radii. As a byproduct, we derive a whole ``numerology'', connecting our gravitational cosmos with the strong micro-cosmoses (hadrons), such that it does imply no variation of G with the epoch. Finally, since a structute of the ``micro-universe'' type seems to be characteristic even of leptons, a hope for the future is including also weak interactions in our classical unification of the fundamental forces.

Hadronic form factor models and spectroscopy within the gauge/gravity correspondence

International Nuclear Information System (INIS)

de Teramond, Guy

2012-01-01

We show that the nonperturbative light-front dynamics of relativistic hadronic bound states has a dual semiclassical gravity description on a higher dimensional warped AdS space in the limit of zero quark masses. This mapping of AdS gravity theory to the boundary quantum field theory, quantized at fixed light-front time, allows one to establish a precise relation between holographic wave functions in AdS space and the light-front wavefunctions describing the internal structure of hadrons. The resulting AdS/QCD model gives a remarkably good accounting of the spectrum, elastic and transition form factors of the light-quark hadrons in terms of one parameter, the QCD gap scale. The light-front holographic approach described here thus provides a frame-independent first approximation to the light-front Hamiltonian problem for QCD. This article is based on lectures at the Niccolo Cabeo International School of Hadronic Physics, Ferrara, Italy, May 2011.

Hadronic form factor models and spectroscopy within the gauge/gravity correspondence

Energy Technology Data Exchange (ETDEWEB)

de Teramond, Guy F.; /Costa Rica U.; Brodsky, Stanley J.; /SLAC

2012-03-20

We show that the nonperturbative light-front dynamics of relativistic hadronic bound states has a dual semiclassical gravity description on a higher dimensional warped AdS space in the limit of zero quark masses. This mapping of AdS gravity theory to the boundary quantum field theory, quantized at fixed light-front time, allows one to establish a precise relation between holographic wave functions in AdS space and the light-front wavefunctions describing the internal structure of hadrons. The resulting AdS/QCD model gives a remarkably good accounting of the spectrum, elastic and transition form factors of the light-quark hadrons in terms of one parameter, the QCD gap scale. The light-front holographic approach described here thus provides a frame-independent first approximation to the light-front Hamiltonian problem for QCD. This article is based on lectures at the Niccolo Cabeo International School of Hadronic Physics, Ferrara, Italy, May 2011.

Physics of low-lying hadrons in quark model and effective hadronic approaches. Final report, September 1, 1996 - March 31, 2000

International Nuclear Information System (INIS)

Mizutani, T.

2000-01-01

There were basically three theoretical projects supported by this grant: (1) Use of confined quark models to study low energy hadronic processes; (2) Production of strangeness by Electromagnetic Probes; and (3) Diffractive dissociative production of vector mesons by virtual photons on nucleons. Each of them is summarized in the paper

Di-hadron azimuthal correlation and Mach-like cone structure in a parton/hadron transport model

International Nuclear Information System (INIS)

Ma, G.L.; Zhang, S.; Ma, Y.G.; Huang, H.Z.; Cai, X.Z.; Chen, J.H.; He, Z.J.; Long, J.L.; Shen, W.Q.; Shi, X.H.; Zuo, J.X.

2006-01-01

In the framework of a multi-phase transport model (AMPT) with both partonic and hadronic interactions, azimuthal correlations between trigger particles and associated scattering particles have been studied by the mixing-event technique. The momentum ranges of these particles are 3 T trig T assoc T trig T assoc NN =200 GeV. A Mach-like structure has been observed in correlation functions for central collisions. By comparing scenarios with and without parton cascade and hadronic rescattering, we show that both partonic and hadronic dynamical mechanisms contribute to the Mach-like structure of the associated particle azimuthal correlations. The contribution of hadronic dynamical process cannot be ignored in the emergence of Mach-like correlations of the soft scattered associated hadrons. However, hadronic rescattering alone cannot reproduce experimental amplitude of Mach-like cone on away-side, and the parton cascade process is essential to describe experimental amplitude of Mach-like cone on away-side. In addition, both the associated multiplicity and the sum of p T decrease, while the T > increases, with the impact parameter in the AMPT model including partonic dynamics from string melting scenario

Hadron interactions in quark models

International Nuclear Information System (INIS)

Narodetskij, I.M.

1987-01-01

Some recent developments on the study of quark degrees of freedom in hadron scattering at intermediate energy are reviewed. Physical foundations of the P-matrix approach and the Quark Compound Bag method are discussed including applications to pion-pion, pion-nucleon, nucleon-nucleon and three-nucleon systems

Statistical bootstrap approach to hadronic matter and multiparticle reactions

International Nuclear Information System (INIS)

Ilgenfritz, E.M.; Kripfganz, J.; Moehring, H.J.

1977-01-01

The authors present the main ideas behind the statistical bootstrap model and recent developments within this model related to the description of fireball cascade decay. Mathematical methods developed in this model might be useful in other phenomenological schemes of strong interaction physics; they are described in detail. The present status of applications of the model to various hadronic reactions is discussed. When discussing the relations of the statistical bootstrap model to other models of hadron physics the authors point out possibly fruitful analogies and dynamical mechanisms which are modelled by the bootstrap dynamics under definite conditions. This offers interpretations for the critical temperature typical for the model and indicates futher fields of application. (author)

Quantum chromodynamic quark model study of hadron and few hadron systems

International Nuclear Information System (INIS)

Ji, Chueng-Ryong.

1991-05-01

This report details research progress and results obtained during the one year period December 1, 1990 to November 30, 1991. The research project, entitled ''Quantum Chromodynamic Quark Model Study of Hadron and Few Hadron Systems,'' is supported by grant FG05-90ER40589 between North Carolina State University and the United States Department of Energy. In compliance with grant requirements the principal investigator, Professor Chueng-Ryong Ji, has conducted a research program addressing theoretical investigations of hadron structure and reactions using quantum chromodynamic quark models. This principal investigator has devoted 50% of his time during the academic year and 100% of his time in the summer. This percent effort will continue for the remaining period of the grant. The new, significant research results are briefly summarized in the following sections. Recent progress has been reported in the renewal/continuation grant proposal just submitted to the Department of Energy. Finally, full, detailed descriptions of completed work can be found in the project publications which are listed at the end of this progress report

Hadronization of QCD and effective interactions

International Nuclear Information System (INIS)

Frank, M.R.

1994-01-01

An introductory treatment of hadronization through functional integral calculus and bifocal Bose fields is given. Emphasis is placed on the utility of this approach for providing a connection between QCD and effective hadronic field theories. The hadronic interactions obtained by this method are nonlocal due to the QCD substructure, yet, in the presence of an electromagnetic field, maintain the electromagnetic gauge invariance manifest at the quark level. A local chiral model which is structurally consistent with chiral perturbation theory is obtained through a derivative expansion of the nonlocalities with determined, finite coefficients. Tree-level calculations of the pion form factor and π - π scattering, which illustrate the dual constituent-quark-chiral-model nature of this approach, are presented

Superconformal Algebraic Approach to Hadron Structure

Energy Technology Data Exchange (ETDEWEB)

de Teramond, Guy F. [Univ. of Costa Rica, San Pedro (Costa Rica); Brodsky, Stanley J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Deur, Alexandre [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Dosch, Hans Gunter [Heidelberg Univ. (Germany). Inst. for Theoretische Physik; Sufian, Raza Sabbir [Univ. of Kentucky, Lexington, KY (United States)

2017-03-01

Fundamental aspects of nonperturbative QCD dynamics which are not obvious from its classical Lagrangian, such as the emergence of a mass scale and confinement, the existence of a zero mass bound state, the appearance of universal Regge trajectories and the breaking of chiral symmetry are incorporated from the onset in an effective theory based on superconformal quantum mechanics and its embedding in a higher dimensional gravitational theory. In addition, superconformal quantum mechanics gives remarkable connections between the light meson and nucleon spectra. This new approach to hadron physics is also suitable to describe nonperturbative QCD observables based on structure functions, such as GPDs, which are not amenable to a first-principle computation. The formalism is also successful in the description of form factors, the nonperturbative behavior of the strong coupling and diffractive processes. We also discuss in this article how the framework can be extended rather successfully to the heavy-light hadron sector.

Modelling hadronic interactions in HEP MC generators

CERN Document Server

Skands, Peter

2015-01-01

HEP event generators aim to describe high-energy collisions in full exclusive detail. They combine perturbative matrix elements and parton showers with dynamical models of less well-understood phenomena such as hadronization, diffraction, and the so-called underlying event. We briefly summarise some of the main concepts relevant to the modelling of soft/inclusive hadron interactions in MC generators, in particular PYTHIA, with emphasis on questions recently highlighted by LHC data.

Colour intransparency and the cross sections for colour-singlet and colour-octet hadrons in the Low-Nussinov model

International Nuclear Information System (INIS)

Dolejsi, J.; Huefner, J.

1992-01-01

The dependence of cross sections on the colour state of the colliding hadrons is investigated within the Low-Nussinov model of two-gluon exchange. The total cross sections for colour-octet hadrons are practically constant as functions of the hadronic radii, while they tend to zero when the radii of the colour-singlet hadrons approach zero. The slope parameter of the differential elastic cross sections for small momentum transfers is rather insensitive to the colour structure of the colliding hadrons. The integrated colour exchange cross section is calculated. (orig.)

Artificial Neural Networks For Hadron Hadron Cross-sections

International Nuclear Information System (INIS)

ELMashad, M.; ELBakry, M.Y.; Tantawy, M.; Habashy, D.M.

2011-01-01

In recent years artificial neural networks (ANN ) have emerged as a mature and viable framework with many applications in various areas. Artificial neural networks theory is sometimes used to refer to a branch of computational science that uses neural networks as models to either simulate or analyze complex phenomena and/or study the principles of operation of neural networks analytically. In this work a model of hadron- hadron collision using the ANN technique is present, the hadron- hadron based ANN model calculates the cross sections of hadron- hadron collision. The results amply demonstrate the feasibility of such new technique in extracting the collision features and prove its effectiveness

A rotating bag model for hadrons. 2

International Nuclear Information System (INIS)

Iwasaki, Masaharu

1994-01-01

The MIT bag model is modified in order to describe rotational motion of hadrons. It has a kind of 'diatomic molecular' structure; The rotational excitation of the MIT bag is described by the polarized two colored sub-bags which are connected with each other by the gluon flux. One sub-bag contains a quark and the other has an antiquark for mesons. For baryons, the latter sub-bag contains the remaining two quarks instead of the antiquark. The Regge trajectories of hadrons are explained qualitatively by our new model with the usual MIT bag parameters. In particular the Regge slopes are reproduced fairly well. It is also pointed out that the gluon flux plays an important role in the rotational motion of hadrons. (author)

Strange Hadronic Matter in a Chiral Model

Institute of Scientific and Technical Information of China (English)

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

2000-01-01

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

Hadron Azimuthal Correlations and Mach-like Structures in a Partonic/Hadronic Transport Model

International Nuclear Information System (INIS)

Ma, G.L.; Zhang, S.; Ma, Y.G.; Cai, X.Z.; Chen, J.H.; He, Z.J.; Huang, H.Z.; Long, J.L.; Shen, W.Q.; Shi, X.H.; Zhong, C.; Zuo, J.X.

2007-01-01

With a multi-phase transport model (AMPT) with both partonic and hadronic interactions, two- and three-particle azimuthal correlations in Au + Au collisions at s NN =200 GeV have been studied by the mixing-event technique. A Mach-like structure has been observed in two- and three-particle correlations in central collisions. It has been found that both partonic and hadronic dynamical mechanisms contribute to the Mach-like structure. However, only hadronic rescattering is unable to reproduce experimental amplitude of Mach-like structure, and parton cascade process is indispensable. The results of three-particle correlation indicate a partonic Mach-like shock wave can be produced by strong parton cascade in central Au+Au collisions

Test of a chromomagnetic model for hadron mass differences

Science.gov (United States)

Lichtenberg, D. B.; Roncaglia, R.

1993-05-01

An oversimplified model consisting of the QCD color-magnetic interaction has been used previously by Silvestre-Brac and others to compare the masses of exotic and normal hadrons. We show that the model can give qualitatively wrong answers when applied to systems of normal hadrons.

Test of a chromomagnetic model for hadron mass differences

International Nuclear Information System (INIS)

Lichtenberg, D.B.; Roncaglia, R.

1993-01-01

An oversimplified model consisting of the QCD color-magnetic interaction has been used previously by Silvestre-Brac and others to compare the masses of exotic and normal hadrons. We show that the model can give qualitatively wrong answers when applied to systems of normal hadrons

The QCD model of hadron cores of the meson theory

International Nuclear Information System (INIS)

Pokrovskii, Y.E.

1985-01-01

It was shown that in the previously proposed QCD model of hadron cores the exchange and self-energy contributions of the virtual quark-antiquark-gluon cloud on the outside of a bag which radius coincides with the hardon core radius of the meson theory (∼ 0.4 Fm) have been taken into account at the phenomenological level. Simulation of this cloud by the meson field results in realistic estimations of the nucleon's electroweak properties, moment fractions carried by gluons, quarks, antiquarks and hadron-hadron interaction cross-sections within a wide range of energies. The authors note that the QCD hadron core model proposed earlier not only realistically reflects the hadron masses, but reflects self-consistently main elements of the structure and interaction of hadrons at the quark-gluon bag radius (R - 0.4Fm) being close to the meson theory core radius

Leading-order calculation of hadronic contributions to the Muon g-2 using the Dyson-Schwinger approach

Science.gov (United States)

Goecke, Tobias; Fischer, Christian S.; Williams, Richard

2011-10-01

We present a calculation of the hadronic vacuum polarisation (HVP) tensor within the framework of Dyson-Schwinger equations. To this end we use a well-established phenomenological model for the quark-gluon interaction with parameters fixed to reproduce hadronic observables. From the HVP tensor we compute both the Adler function and the HVP contribution to the anomalous magnetic moment of the muon, aμ. We find aμHVP = 6760 ×10-11 which deviates about two percent from the value extracted from experiment. Additionally, we make comparison with a recent lattice determination of aμHVP and find good agreement within our approach. We also discuss the implications of our result for a corresponding calculation of the hadronic light-by-light scattering contribution to aμ.

Leading-order calculation of hadronic contributions to the Muon g-2 using the Dyson-Schwinger approach

International Nuclear Information System (INIS)

Goecke, Tobias; Fischer, Christian S.; Williams, Richard

2011-01-01

We present a calculation of the hadronic vacuum polarisation (HVP) tensor within the framework of Dyson-Schwinger equations. To this end we use a well-established phenomenological model for the quark-gluon interaction with parameters fixed to reproduce hadronic observables. From the HVP tensor we compute both the Adler function and the HVP contribution to the anomalous magnetic moment of the muon, a μ . We find a μ HVP =6760x10 -11 which deviates about two percent from the value extracted from experiment. Additionally, we make comparison with a recent lattice determination of a μ HVP and find good agreement within our approach. We also discuss the implications of our result for a corresponding calculation of the hadronic light-by-light scattering contribution to a μ .

Hadronic mass-relations from topological expansion and string model

International Nuclear Information System (INIS)

Kaidalov, A.B.

1980-01-01

Hadronic mass-relations from topological expansion and string model are derived. For this purpose the space- time picture of hadron interactions at high energies corresponding to planar diagrams of topological expansion is considered. Simple relations between intercepts and slopes of Regge trajectories based on the topological expansion and q anti q-string picture of hadrons are obtained [ru

High energy hadron-hadron collisions. Annual progress report

International Nuclear Information System (INIS)

Chou, T.T.

1979-03-01

Work on high energy hadron-hadron collisions in the geometrical model, performed under the DOE Contract No. EY-76-S-09-0946, is summarized. Specific items studied include the behavior of elastic hadron scatterings at super high energies and the existence of many dips, the computation of meson radii in the geometrical model, and the hadronic matter current effects in inelastic two-body collisions

Nuclei, hadrons, and elementary particles

International Nuclear Information System (INIS)

Bopp, F.W.

1989-01-01

This book is a short introduction to the physics of the nuclei, hadrons, and elementary particles for students of physics. Important facts and model imaginations on the structure, the decay, and the scattering of nuclei, the 'zoology' of the hadrons and basic facts of hadronic scattering processes, a short introduction to quantum electrodynamics and quantum chromodynamics and the most important processes of lepton and parton physics, as well as the current-current approach of weak interactions and the Glashow-Weinberg-Salam theory are presented. (orig.) With 153 figs., 10 tabs [de

Particle ratios from AGS to RHIC in an interacting hadronic model

International Nuclear Information System (INIS)

Zschiesche, D; Zeeb, G; Paech, K; Schramm, S; Stoecker, H

2004-01-01

The measured particle ratios in central heavy-ion collisions at RHIC-BNL are investigated within a chemical and thermal equilibrium chiral SU(3) σ-ωapproach. The commonly adopted non-interacting gas calculations yield temperatures close to or above the critical temperature for the chiral phase transition, but without taking into account any interactions. In contrast, the chiral SU(3) model predicts temperature and density dependent effective hadron masses and effective chemical potentials in the medium and a transition to a chirally restored phase at high temperatures or chemical potentials. Three different parametrizations of the model, which show different types of phase transition behaviour, are investigated. We show that if a chiral phase transition occured in those collisions, 'freezing' of the relative hadron abundances in the symmetric phase is excluded by the data. Therefore, either very rapid chemical equilibration must occur in the broken phase, or the measured hadron ratios are the outcome of the dynamical symmetry breaking. Furthermore, the extracted chemical freeze-out parameters differ considerably from those obtained in simple non-interacting gas calculations. In particular, the three models yield up to 35 MeV lower temperatures than the free gas approximation. The in-medium masses turn out to differ up to 150 MeV from their vacuum values

Composite models of hadrons and relativistic bound states

International Nuclear Information System (INIS)

Filippov, A.T.

1977-01-01

The following problems are considered: what the constituents of the hadrons are; what their quantum numbers and their broken and unbroken symmetries are; what the dynamics of the constituents (equations, binding forces and the origin of symmetry violations) is. The most puzzling question is: why the constituents ''escape from freedom'' and are confined inside the hadrons; what experimentalists can report about the hadron constituents and their dynamics if not finding them. There are no final answers to all these questions. The achievements of quark model are described, some problems concerning the comparison of the quark model with experiment are considered. The attempt is also made to present alternative views on the same problems

Spin effects in elastic scattering of nucleons and new approach to problem of account for spin structure of hadrons

International Nuclear Information System (INIS)

Babaev, Z.R.; Shchelkachev, A.V.

1991-01-01

Prospects of decribing polarization effects within the framework of quark-parton models (QPM) using a density matrix in order to describe the parton spin states in hadrons are discussed. Such an approach allows one to get rid of contradictions occuring when describing the QPM of reactions of hadrons polarized in perpendicular to the scattering plane in case of applying spin distribution functions. Different model predictions for the observed one- and two-spin correlations in elastic nucleon-nucleon scattering are analyzed. 12 refs., 2 tabs

A quark-antiquark formation model for meson production in low transverse momentum hadron-hadron reactions

International Nuclear Information System (INIS)

Friebel, W.; Kriegel, U.; Nahnhauer, R.

1979-01-01

Introducing quark transverse momenta and masses it is proposed a 3-dimensional generalization of the quark recombination and the quark fusion model for meson production in low transverse momentum hadron-hadron reactions. A consistent description of vector meson production in proton-proton and proton-antiproton reactions from 12 - 405 GeV/c has been achieved. (author)

Nonscaling parametrization of hadronic spectra and dual parton model

International Nuclear Information System (INIS)

Gaponenko, O.N.

2001-01-01

Using the popular Wdowczyk-Wolfendale parametrization (WW-parametrization) as an example one studies restrictions imposed by a dual parton model for different nonscaling parametrizations of the pulsed hadron spectra in soft hadron-hadron and hadron-nuclear interactions. One derived a new parametrization free from basic drawback of the WW-formulae. In the central range the determined parametrization show agreement with the Wdowczyk-Wolfendale formula, but in contrast to the last-named one it does not result in contradiction with the experiment due to fast reduction of inelastic factor reduction with energy increase [ru

Leading-order calculation of hadronic contributions to the Muon g-2 using the Dyson-Schwinger approach

Energy Technology Data Exchange (ETDEWEB)

Goecke, Tobias [Institut fuer Theoretische Physik, Universitaet Giessen, 35392 Giessen (Germany); Fischer, Christian S., E-mail: christian.fischer@theo.physik.uni-giessen.de [Institut fuer Theoretische Physik, Universitaet Giessen, 35392 Giessen (Germany); Gesellschaft fuer Schwerionenforschung mbH, Planckstr. 1, D-64291 Darmstadt (Germany); Williams, Richard [Dept. Fisica Teorica I, Universidad Complutense, 28040 Madrid (Spain)

2011-10-13

We present a calculation of the hadronic vacuum polarisation (HVP) tensor within the framework of Dyson-Schwinger equations. To this end we use a well-established phenomenological model for the quark-gluon interaction with parameters fixed to reproduce hadronic observables. From the HVP tensor we compute both the Adler function and the HVP contribution to the anomalous magnetic moment of the muon, a{sub {mu}}. We find a{sub {mu}}{sup HVP}=6760x10{sup -11} which deviates about two percent from the value extracted from experiment. Additionally, we make comparison with a recent lattice determination of a{sub {mu}}{sup HVP} and find good agreement within our approach. We also discuss the implications of our result for a corresponding calculation of the hadronic light-by-light scattering contribution to a{sub {mu}.}

Exotic hadron production in a quark combination model

International Nuclear Information System (INIS)

Han Wei; Shao Fenglan; Li Shiyuan; Shang Yonghui; Yao Tao

2009-01-01

The philosophy on production of exotic hadrons (multiquark states) in the framework of the quark combination model is investigated, taking f 0 (980) as an example. The production rate and p T spectra of f 0 (980) considered as (ss) or (sqsq), respectively, are calculated and compared in Au+Au collisions at √(s NN )=200 GeV. The unitarity of various combination models, when open for exotic hadron production, is addressed.

Pairing in hadron structure

International Nuclear Information System (INIS)

Chela-Flores, J.

1981-08-01

A many-body approach to hadron structure is presented, in which we consider two parton species: spin-0 (b-partons), and spin-1/2 (f-partons). We extend a boson and a fermion pairing scheme for the b-, and f-partons respectively, into a Yang-Mills gauge theory. The main feature of this theory is that the gauge field is not identified with the usual gluon field variable in QCD. We study the confinement problem of the hadron constituents, and obtain, for low temperatures, partons that are confined by energy gaps. As the critical temperatures for the corresponding phase transitions are approached, the energy gap gradually disappears, and confinement is lost. The theory goes beyond the non-relativistic harmonic oscillator quark model, in the sense of giving physical reasons why a non-relativistic approximation is adequate in describing the internal dynamics of hadron structure. (author)

Mean transverse momenta correlations in hadron-hadron collisions in MC toy model with repulsing strings

International Nuclear Information System (INIS)

Altsybeev, Igor

2016-01-01

In the present work, Monte-Carlo toy model with repulsing quark-gluon strings in hadron-hadron collisions is described. String repulsion creates transverse boosts for the string decay products, giving modifications of observables. As an example, long-range correlations between mean transverse momenta of particles in two observation windows are studied in MC toy simulation of the heavy-ion collisions

Hadron structure in a simple model of quark/nuclear matter

International Nuclear Information System (INIS)

Horowitz, C.J.; Moniz, E.J.; Negele, J.W.

1985-01-01

We study a simple model for one-dimensional hadron matter with many of the essential features needed for examining the transition from nuclear to quark matter and the limitations of models based upon hadron rather than quark degrees of freedom. The dynamics are generated entirely by the quark confining force and exchange symmetry. Using Monte Carlo techniques, the ground-state energy, single-quark momentum distribution, and quark correlation function are calculated for uniform matter as a function of density. The quark confinement scale in the medium increases substantially with increasing density. This change is evident in the correlation function and momentum distribution, in qualitative agreement with the changes observed in deep-inelastic lepton scattering. Nevertheless, the ground-state energy is smooth throughout the transition to quark matter and is described remarkably well by an effective hadron theory based on a phenomenological hadron-hadron potential

Improved modelling of independent parton hadronization

International Nuclear Information System (INIS)

Biddulph, P.; Thompson, G.

1989-01-01

A modification is proposed to current versions of the Field-Feynman ansatz for the hadronization of a quark in Monte Carlo models of QCD interactions. This faster-running algorithm has no more parameters and imposes a better degree of energy conservation. It results in naturally introducing a limitation of the transverse momentum distribution, similar to the experimentally observed ''seagull'' effect. There is now a much improved conservation of quantum numbers between the original parton and resultant hadrons, and the momentum of the emitted parton is better preserved in the summed momentum vectors of the final state particles. (orig.)

Collective vs atomic models of the hadrons

International Nuclear Information System (INIS)

Stokar, S.

1983-02-01

We examine the relationship between heavy and light quark systems. Using a Bogoliubov-Valatin transformation we show how to interpolate continuously between heavy quark atomic models and light quark collective models of the hadrons. (author)

A Feynman-Hellmann approach to the spin structure of hadrons

Energy Technology Data Exchange (ETDEWEB)

Chambers, A.J. [Adelaide Univ., SA (Australia). CSSM, Dept. of Physics; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe (Japan); Collaboration: CSSM and QCDSF/UKQCD Collaborations; and others

2014-05-15

We perform a N{sub f}=2+1 lattice QCD simulation to determine the quark spin fractions of hadrons using the Feynman-Hellmann theorem. By introducing an external spin operator to the fermion action, the matrix elements relevant for quark spin fractions are extracted from the linear response of the hadron energies. Simulations indicate that the Feynman-Hellmann method offers statistical precision that is comparable to the standard three-point function approach, with the added benefit that it is less susceptible to excited state contamination. This suggests that the Feynman-Hellmann technique offers a promising alternative for calculations of quark line disconnected contributions to hadronic matrix elements. At the SU(3)-flavour symmetry point, we find that the connected quark spin fractions are universally in the range 55-70% for vector mesons and octet and decuplet baryons. There is an indication that the amount of spin suppression is quite sensitive to the strength of SU(3) breaking.

High energy hadron-hadron collisions

International Nuclear Information System (INIS)

Chou, T.T.

1990-01-01

Results of a study on high energy collision with the geometrical model are summarized in three parts: (i) the elastic hadron-hadron collision, (ii) the inelastic hadron-hadron collision, and (iii) the e + e - annihilation. The geometrical description of high-energy elastic scattering developed earlier is still in general agreement with experiments at the CERN-S bar ppS energies. A simple one-parameter expression for the blackness of bar pp system has been proposed recently which describes very well all existing data from ISR to S bar ppS energies. The geometrical description has also been extended to include processes of fragmentation and diffraction dissociation and other phenomena. In the past five years, a unified physical picture for multiparticle emission in hadron-hadron and e + e - collisions was developed. It focuses on the idea of the wide range of values for the total angular momentum in hadron-hadron collisions. An extension of this consideration yields a theory for the momentum distribution of the outgoing particles which agrees with bar pp and e + e - collision experiments. The results and conclusions of this theory have been extrapolated to higher energies and yielded many predictions which can be experimentally tested. 37 refs

Integral equations of hadronic correlation functions a functional- bootstrap approach

CERN Document Server

Manesis, E K

1974-01-01

A reasonable 'microscopic' foundation of the Feynman hadron-liquid analogy is offered, based on a class of models for hadron production. In an external field formalism, the equivalence (complementarity) of the exclusive and inclusive descriptions of hadronic reactions is specifically expressed in a functional-bootstrap form, and integral equations between inclusive and exclusive correlation functions are derived. Using the latest CERN-ISR data on the two-pion inclusive correlation function, and assuming rapidity translational invariance for the exclusive one, the simplest integral equation is solved in the 'central region' and an exclusive correlation length in rapidity predicted. An explanation is also offered for the unexpected similarity observed between pi /sup +/ pi /sup -/ and pi /sup -/ pi /sup -/ inclusive correlations. (31 refs).

Polyakov loop and the hadron resonance gas model.

Science.gov (United States)

Megías, E; Arriola, E Ruiz; Salcedo, L L

2012-10-12

The Polyakov loop has been used repeatedly as an order parameter in the deconfinement phase transition in QCD. We argue that, in the confined phase, its expectation value can be represented in terms of hadronic states, similarly to the hadron resonance gas model for the pressure. Specifically, L(T)≈1/2[∑(α)g(α)e(-Δ(α)/T), where g(α) are the degeneracies and Δ(α) are the masses of hadrons with exactly one heavy quark (the mass of the heavy quark itself being subtracted). We show that this approximate sum rule gives a fair description of available lattice data with N(f)=2+1 for temperatures in the range 150 MeVmodels. For temperatures below 150 MeV different lattice results disagree. One set of data can be described if exotic hadrons are present in the QCD spectrum while other sets do not require such states.

An object-oriented framework for the hadronic Monte-Carlo event generators

International Nuclear Information System (INIS)

Amelin, N.; Komogorov, M.

1999-01-01

We advocate the development of an object-oriented framework for the hadronic Monte-Carlo (MC) event generators. The hadronic MC user and developer requirements are discussed as well as the hadronic model commonalities. It is argued that the development of a framework is in favour of taking into account of model commonalities since common means are stable and can be developed only at once. Such framework can provide different possibilities to have user session more convenient and productive, e.g., an easy access and edition of any model parameter, substitution of the model components by the alternative model components without changing the code, customized output, which offers either full information about history of generated event or specific information about reaction final state, etc. Such framework can indeed increase the productivity of a hadronic model developer, particularly, due to the formalization of the hadronic model component structure and model component collaborations. The framework based on the component approach opens a way to organize a library of the hadronic model components, which can be considered as the pool of hadronic model building blocks. Basic features, code structure and working examples of the first framework version for the hadronic MC models, which has been built as the starting point, are shortly explained

Strangeness production in hadronic and nuclear collisions in the dual parton model

International Nuclear Information System (INIS)

Capella, A.; Tran Thanh Van, J.; Ranft, J.

1993-01-01

Λ, antiΛ and K s 0 production is studied in a Monte Carlo Dual Parton model for hadron-hadron, hadron-nucleus and nucleus-nucleus collisions with a SU(3) symmetric sea for chain formation (chain ends) but strangeness suppression in the chain fragmentation. Additionally, (qq)-(antiqantiq) production from the sea was introduced into the chain formation process with the same probability as for the q → qq branching within the chain decay process. This together with the popcorn mechanism of diquark fragmentation result in a new central component of hyperon production, which was not present in previous versions of the model. With these assumptions rapidity distributions and multiplicity ratios for strange particles in hadron-hadron, hadron-nucleus and nucleus-nucleus collisions are compared to a comprehensive collection of experimental data. 5 figs., 2 tabs., 15 refs

Hadron structure in the ladder model

International Nuclear Information System (INIS)

Soper, D.E.

1979-01-01

The (flavor non-singlet) Green's function to find a far-off-shell quark in a hadron is obtained in the renormalization group improved ladder model for QCD in the space-like axial gauge. Particular attention is paid to the role of the singularity in the gluon propagator. 4 figures

Quasirelativistic quark model in quasipotential approach

CERN Document Server

Matveev, V A; Savrin, V I; Sissakian, A N

2002-01-01

The relativistic particles interaction is described within the frames of quasipotential approach. The presentation is based on the so called covariant simultaneous formulation of the quantum field theory, where by the theory is considered on the spatial-like three-dimensional hypersurface in the Minkowski space. Special attention is paid to the methods of plotting various quasipotentials as well as to the applications of the quasipotential approach to describing the characteristics of the relativistic particles interaction in the quark models, namely: the hadrons elastic scattering amplitudes, the mass spectra and widths mesons decays, the cross sections of the deep inelastic leptons scattering on the hadrons

Phase transition in the hadron gas model

International Nuclear Information System (INIS)

Gorenstein, M.I.; Petrov, V.K.; Zinov'ev, G.M.

1981-01-01

A class of statistical models of hadron gas allowing an analytical solution is considered. A mechanism of a possible phase transition in such a system is found and conditions for its occurence are determined [ru

Hadronic photon-photon interactions at high energies

International Nuclear Information System (INIS)

Engel, R.; Siegen Univ.; Ranft, J.

1996-01-01

Photon-photon collisions are investigated in the framework of the two-component Dual Parton Model. The model contains contributions from direct, resolved soft and resolved hard interactions. All free parameters of the model are determined in fits to hadron-hadron and photon-hadron cross section data. The model is shown to agree well to hadron production data from hadron-hadron and photon-hadron collisions. The multiparticle production in hadron-hadron, photon-hadron and photon-photon collisions as predicted by the model is compared. Strong differences are only found as function of the transverse momentum variable. (author)

Chiral perturbation theory approach to hadronic weak amplitudes

International Nuclear Information System (INIS)

Rafael, E. de

1989-01-01

We are concerned with applications to the non-leptonic weak interactions in the sector of light quark flavors: u, d and s. Both strangeness changing ΔS=1 and ΔS=2 non-leptonic transitions can be described as weak perturbations to the strong effective chiral Lagrangian; the chiral structure of the weak effective Lagrangian being dictated by the transformation properties of the weak non-leptonic Hamiltonian of the Standard Model under global SU(3) Left xSU(3) Right rotations of the quark-fields. These lectures are organized as follows. Section 2 gives a review of the basic properties of chiral symmetry. Section 3 explains the effective chiral realization of the non-leptonic weak Hamiltonian of the Standard Model to lowest order in derivatives and masses. Section 4 deals with non-leptonic weak transitions in the presence of electromagnetism. Some recent applications to radiative kaon decays are reviewed and the effect of the so called electromagnetic penguin like diagrams is also discussed. Section 5 explains the basic ideas of the QCD-hadronic duality approach to the evaluation of coupling constants of the non-leptonic chiral weak Lagrangian. (orig./HSI)

Systematic approach to inclusive lepton pair production in hadronic collisions

International Nuclear Information System (INIS)

Lam, C.S.; Tung, W.

1978-01-01

Strong-interaction dynamics as probed by lepton pair production in hadronic collisions is naturally separated from kinematics by using suitably defined structure functions. In the first part of this paper, general properties of invariant structure functions and a variety of ''helicity'' structure functions for this process are studied, and their use discussed. An exact parallelism to the case of deep-inelastic lepton-hadron scattering is set up. In the second part, a series of parton-model relations between the structure functions, reflecting the basic Drell-Yan on-shell quark-antiquark annihilation picture (but independent of details of parton distributions), is derived. These relations serve the dual purposes of (i) supplementing the model-independent structure-function formalism and rendering it useful for analyzing data of limited scope initially, and (ii) providing unambiguous tests of various aspects of the underlying quark-parton model when more detailed data become available

Hadronic equation of state in the statistical bootstrap model and linear graph theory

International Nuclear Information System (INIS)

Fre, P.; Page, R.

1976-01-01

Taking a statistical mechanical point og view, the statistical bootstrap model is discussed and, from a critical analysis of the bootstrap volume comcept, it is reached a physical ipothesis, which leads immediately to the hadronic equation of state provided by the bootstrap integral equation. In this context also the connection between the statistical bootstrap and the linear graph theory approach to interacting gases is analyzed

Multiplicity distributions in a thermodynamical model of hadron production in e+e- collisions

International Nuclear Information System (INIS)

Becattini, F.; Giovannini, A.; Lupia, S.

1996-01-01

Predictions of a thermodynamical model of hadron production for multiplicity distributions in e + e - annihilations at LEP and PEP-PETRA centre of mass energies are shown. The production process is described as a two-step process in which primary hadrons emitted from the thermal source decay into final observable particles. The final charged track multiplicity distributions turn out to be of negative binomial type and are in quite good agreement with experimental observations. The average number of clans calculated from fitted negative binomial coincides with the average number of primary hadrons predicted by the thermodynamical model, suggesting that clans should be identified with primary hadrons. (orig.)

Unified model of current-hadronic interactions. II

International Nuclear Information System (INIS)

Moffat, J.W.; Wright, A.C.D.

1975-01-01

An analytic model of current-hadronic interactions is used to make predictions which are compared with recent data for vector-meson electroproduction and for the spin density matrix of photoproduced rho 0 mesons. The rho 0 and ω electroproduction cross sections are predicted to behave differently as the mass of the virtual photon varies; the diffraction peak broadens with increasing -q 2 at fixed ν and narrows with increasing energy. The predicted rho 0 density matrix elements do not possess the approximate s-channel helicity conservation seen experimentally. The model is continued to the inclusive electron-positron annihilation region, where parameter-free predictions are given for the inclusive prosess e + + e - → p + hadrons. The annihilation structure functions are found to have nontrivial scale-invariance limits. By using total cross-section data for e + e - annihilation into hardrons, we predict the mean multiplicity for the production of nucleons

Influence of heavy hadronic states on the QCD phase diagram and on the freeze-out within a hadronic chiral model

International Nuclear Information System (INIS)

Zeeb, G.

2006-01-01

In this thesis the thermodynamical properties of strongly interacting hadronic matter and the microscopic in-medium properties of hadrons are investigated at high temperatures and high baryonic densities within a chiral flavor-SU(3) model. The applied model is a generalized σ-ω model in mean-field approximation with baryons and mesons as effective degrees of freedom. It is built on spontaneously broken chiral symmetry and scale invariance. The phase transition behavior is systematically analyzed and is thus shown to depend significantly on the couplings of additional heavier hadronic degrees of freedom. A phase diagram in qualitative agreement with current lattice QCD (lQCD) calculations can result from an according coupling of the lowest lying baryonic decuplet to the model. Alternatively, the coupling of a heavy baryonic test-resonance is investigated, which effectively represents the spectrum of the heavy hadronic states. For a certain range of parameters one can even obtain a phase diagram in quantitative agreement with the lQCD calculations and, simultaneously, a successful description of the ground state properties of nuclear matter. It is shown that (within the model assumptions) the phase transition region is experimentally accessible for the CBM experiment at the upcoming FAIR facility at GSI Darmstadt. The chiral model is further applied to particle yield ratios measured in heavy-ion collisions from AGS, SPS and RHIC. For these investigations parameter sets with strongly differing phase diagrams due to different couplings of the baryon decuplet are used and in addition an ideal hadron gas. At the lower and mid collision energies the chiral parameter sets show an improved description as compared to the ideal hadron gas, especially for parameter sets with phase diagrams similar to the lQCD predictions. The interaction within the chiral model leads to in-medium modifications of the chemical potentials and the hadron masses. Therefore the resulting freeze

Hadron reaction mechanisms

International Nuclear Information System (INIS)

Collins, P.D.B.; Martin, A.D.

1982-01-01

The mechanism of hadron scattering at high energies are reviewed in such a way as to combine the ideas of the parton model and quantum chromodynamics (QCD) with Regge theory and phenomenology. After a brief introduction to QCD and the basic features of hadron scattering data, scaling and the dimensional counting rules, the parton structure of hadrons, and the parton model for large momentum transfer processes, including scaling violations are discussed. Hadronic jets and the use of parton ideas in soft scattering processes are examined, attention being paid to Regge theory and its applications in exclusive and inclusive reactions, the relationship to parton exchange being stressed. The mechanisms of hadron production which build up cross sections, and hence the underlying Regge singularities, and the possible overlap of Regge and scaling regions are discussed. It is concluded that the key to understanding hadron reaction mechanisms seems to lie in the marriage of Regge theory with QCD. (author)

A model of hadron structure

International Nuclear Information System (INIS)

Migdal, A.B.; Khokhlachev, S.B.; Borue, V.Yu.

1989-01-01

The hadron is considered as a stringlike gluon drop with a quark and antiquark near the ends of the 'string' for a meson and with the antiquark replaced by a diquark for a baryon. The softer 'string' modes are the rotations and the longitudinal vibrations. Quantization of these modes enables to describe the hadron spectra. (orig.)

A deformable bag model of hadrons, 1

International Nuclear Information System (INIS)

Ui, Haruo; Saito, Koich

1983-01-01

As a generalization of the MIT spherical bag model, we construct the spheroidal bag model of hadron with an arbitrary eccentricity. This generalization is made by slightly modifying the MIT linear boundary condition: The linear boundary condition is examined in detail. Our model always satisfies two necessary requirements of the MIT bag model - i.e., n.j = 0, no quark colour flux leaves the bag, and q-barq = 0, the scalar density of quark should vanish on the bag surface- and it reduces to the MIT spherical bag model in the limit of zero-eccentricity. Lagrangian formalism of our model is briefly described. The eigenfrequencies of a single massless quark confined in this spheroidal bag are numerically calculated. We obtain the level-splitting of the excited quark orbits, which is just analogous to the well-known Nilsson's splitting of single particle orbits in deformed nuclei. By using the numerical results of the lowest orbit, the effect of the bag-deformation on the mass of low-lying hadrons is estimated. It is found that, although the spherical bag is stable, the quark bag is extremely soft against the quadrupole deformation. Brief discussions are added on the mechanisms which make the spherical bag more stable. (author)

The strong coupling constant: its theoretical derivation from a geometric approach to hadron structure

International Nuclear Information System (INIS)

Recami, E.; Tonin-Zanchin, V.

1991-01-01

Since more than a decade, a bi-scale, unified approach to strong and gravitational interactions has been proposed, that uses the geometrical methods of general relativity, and yielded results similar to strong gravity theory's. We fix our attention, in this note, on hadron structure, and show that also the strong interaction strength α s, ordinarily called the (perturbative) coupling-constant square, can be evaluated within our theory, and found to decrease (increase) as the distance r decreases (increases). This yields both the confinement of the hadron constituents for large values of r, and their asymptotic freedom [for small values of r inside the hadron]: in qualitative agreement with the experimental evidence. In other words, our approach leads us, on a purely theoretical ground, to a dependence of α s on r which had been previously found only on phenomenological and heuristical grounds. We expect the above agreement to be also quantitative, on the basis of a few checks performed in this paper, and of further work of ours about calculating meson mass-spectra. (author)

Electromagnetic polarizabilities of hadrons

International Nuclear Information System (INIS)

Friar, J.L.

1988-01-01

Electromagnetic polarizabilities of hadrons are reviewed, after a discussion of classical analogues. Differences between relativistic and non-relativistic approaches can lead to conflicts with conventional nuclear physics sum rules and calculational techniques. The nucleon polarizabilities are discussed in the context of the non-relativistic valence quark model, which provides a good qualitative description. The recently measured pion polarizabilities are discussed in the context of chiral symmetry and quark-loop models. 58 refs., 5 figs

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

International Nuclear Information System (INIS)

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

1986-01-01

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

Geant4 Hadronic Cascade Models and CMS Data Analysis : Computational Challenges in the LHC era

CERN Document Server

Heikkinen, Aatos

This work belongs to the field of computational high-energy physics (HEP). The key methods used in this thesis work to meet the challenges raised by the Large Hadron Collider (LHC) era experiments are object-orientation with software engineering, Monte Carlo simulation, the computer technology of clusters, and artificial neural networks. The first aspect discussed is the development of hadronic cascade models, used for the accurate simulation of medium-energy hadron-nucleus reactions, up to 10 GeV. These models are typically needed in hadronic calorimeter studies and in the estimation of radiation backgrounds. Various applications outside HEP include the medical field (such as hadron treatment simulations), space science (satellite shielding), and nuclear physics (spallation studies). Validation results are presented for several significant improvements released in Geant4 simulation tool, and the significance of the new models for computing in the Large Hadron Collider era is estimated. In particular, we es...

The Baryon Production and Baryon Number Transfer in Hadron-Hadron, Hadron-Nucleus and Nucleus-Nucleus Collisions

International Nuclear Information System (INIS)

Szymanski, P.

2006-09-01

This work concerns soft hadronic interactions which in the Standard Model carry most of the observable cross-section but are not amenable to quantitative predictions due to the very nature of the QCD (Theory of Strong Interactions). In the low momentum transfer region the evolving coupling constant caused perturbation theory to break down. In this situation better experimental understanding of the physics phenomena is needed. One aspect of the soft hadronic interactions will be discussed in this work: transfer of the baryon number from the initial to the final state of the interaction. The past experimental knowledge on this process is presented, reasons for its unsatisfactory status are discussed and condition necessary for improvement are outlined: that is experimental apparatus with superior performance over the full range of available interactions: hadron-hadron collision, hadron-nucleus and nucleus-nucleus interactions. A consistent model-independent picture of the baryon number transfer process emerging from the data on the full range of interactions is shown. It offers serious challenge to theory to provide quantitative and detailed explanation of the measurements. (author)

An SU(5) grand unified model with hadrons as nontopological solitons. Pt. 1

International Nuclear Information System (INIS)

Chen Shihao

1994-01-01

A new grand unified model containing the known three generations of quark and lepton in which hadrons are regarded as nontopological solitons formed from quarks is presented. According to the model leptons and quarks are the same in essence. The differences between them are caused by spontaneous symmetry breaking. When a quark is located inside a hadron, its properties will be the same as those of a known quark and its mass very small. When a quark is outside hadrons, its properties will be the same as those of a known lepton, its mass very large and it will rapidly decay. Except defining charge Q 0 and fermion number F 0 which are exactly conserved, we also define interior colour, interior charge and interior fermion number approximately conserved inside a hadron. The (L-B) conservation in the known SU(5) model corresponds to the fermion number F 0 conservation in the present model

Exactly solvable model of phase transition between hadron and quark-gluon-matter

International Nuclear Information System (INIS)

Gorenstein, M.I.; Petrov, V.K.; Shelest, V.P.; Zinovjev, G.M.

1982-01-01

An exactly solvable model of phase transition between hadron and quark-gluon matter is proposed. The hadron phase of this model is considered as a gas of bags filled by point massless constituents. The mass and volume spectrum of the bag is found. The thermodynamical characteristics of a bag gas in the neighbourhood of a phase transition point are ascertained in analytical form

High energy hadron-nucleus scattering

International Nuclear Information System (INIS)

Koplik, J.; Mueller, A.H.

1975-01-01

Theoretical expectations for hadron-nucleus scattering at high energy if the basic hadron-hadron interaction is due to Regge poles and cuts arising in multiperipheral or soft field theory models are described. Experiments at Fermilab may provide a critical test of such models

Hadron spectroscopy

International Nuclear Information System (INIS)

Oka, Makoto

2012-01-01

Spectra of hadrons show various and complex structures due to the strong coupling constants of the quantum chromodynamics (QCD) constituting its fundamental theory. For their understandings, two parameters, i.e., (1) the quark mass and (2) their excitation energies are playing important roles. In low energies, for example, rather simple structures similar to the positronium appear in the heavy quarks such as charms and bottoms. It has been, however, strongly suggested by the recent experiments that the molecular resonant state shows up when the threshold to decay to mesons is exceeded. On the other hand, chiral symmetry and its breaking play important roles in the dynamics of light quarks. Strange quarks are in between and show special behaviors. In the present lecture, the fundamental concept of the hadron spectroscopy based on the QCD is expounded to illustrate the present understandings and problems of the hadron spectroscopy. Sections are composed of 1. Introduction, 2. Fundamental Concepts (hadrons, quarks and QCD), 3. Quark models and exotic hadrons, 4. Lattice QCD and QCD sum rules. For sections 1 to 3, only outline of the concepts is described because of the limited space. Exotic hadrons, many quark pictures of light hadrons and number of quarks in hadrons are described briefly. (S. Funahashi)

Hadronic wavefunctions in light-cone quantization

International Nuclear Information System (INIS)

Hyer, T.

1994-05-01

The analysis of light-cone wavefunctions seems the most promising theoretical approach to a detailed understanding of the structure of relativistic bound states, particularly hadrons. However, there are numerous complications in this approach. Most importantly, the light-cone approach sacrifices manifest rotational invariance in exchange for the elimination of negative-energy states. The requirement of rotational invariance of the full theory places important constraints on proposed light-cone wavefunctions, whether they are modelled or extracted from some numerical procedure. A formulation of the consequences of the hidden rotational symmetry has been sought for some time; it is presented in Chapter 2. In lattice gauge theory or heavy-quark effective theory, much of the focus is on the extraction of numerical values of operators which are related to the hadronic wavefunction. These operators are to some extent interdependent, with relations induced by fundamental constraints on the underlying wavefunction. The consequences of the requirement of unitarity are explored in Chapter 3, and are found to have startling phenomenological relevance. To test model light-cone wavefunctions, experimental predictions must be made. The reliability of perturbative QCD as a tool for making such predictions has been questioned. In Chapter 4, the author presents a computation of the rates for nucleon-antinucleon annihilation, improving the reliability of the perturbative computation by taking into account the Sudakov suppression of exclusive processes at large transverse impact parameter. In Chapter 5, he develops the analysis of semiexclusive production. This work focuses on processes in which a single isolated meson is produced perturbatively and recoils against a wide hadronizing system. At energies above about 10 GeV, semiexclusive processes are shown to be the most sensitive experimental probes of hadronic structure

Dynamical equilibration in strongly-interacting parton-hadron matter

Directory of Open Access Journals (Sweden)

Gorenstein M.

2011-04-01

Full Text Available We study the kinetic and chemical equilibration in 'infinite' parton-hadron matter within the Parton-Hadron-String Dynamics transport approach, which is based on a dynamical quasiparticle model for partons matched to reproduce lattice-QCD results – including the partonic equation of state – in thermodynamic equilibrium. The 'infinite' matter is simulated within a cubic box with periodic boundary conditions initialized at different baryon density (or chemical potential and energy density. The transition from initially pure partonic matter to hadronic degrees of freedom (or vice versa occurs dynamically by interactions. Different thermody-namical distributions of the strongly-interacting quark-gluon plasma (sQGP are addressed and discussed.

Relativistic direct interaction and hadron models

International Nuclear Information System (INIS)

Biswas, T.

1984-01-01

Direct interaction theories at a nonrelativistic level have been used successfully in several areas earlier (e.g. nuclear physics). But for hadron spectroscopy relativistic effects are important and hence the need for a relativistic direct interaction theory arises. It is the goal of this thesis to suggest such a theory which has the simplicity and the flexibility required for phenomenological model building. In general the introduction of relativity in a direct interaction theory is shown to be non-trivial. A first attempt leads to only an approximate form for allowed interactions. Even this is far too complex for phenomenological applicability. To simplify the model an extra spacelike particle called the vertex is introduced in any set of physical (timelike) particles. The vertex model is successfully used to fit and to predict experimental data on hadron spectra, γ and psi states fit very well with an interaction function inspired by QCD. Light mesons also fit reasonably well. Better forms of hyperfine interaction functions would be needed to improve the fitting of light mesons. The unexpectedly low pi meson mass is partially explained. Baryon ground states are fitted with unprecedented accuracy with very few adjustable parameters. For baryon excited states it is shown that better QCD motivated interaction functions are needed for a fit. Predictions for bb states in e + e - experiments are made to assist current experiments

A correlated-cluster model and the ridge phenomenon in hadron-hadron collisions

CERN Document Server

Sanchis-Lozano, Miguel-Angel

2017-03-10

A study of the near-side ridge phenomenon in hadron-hadron collisions based on a cluster picture of multiparticle production is presented. The near-side ridge effect is shown to have a natural explanation in this context provided that clusters are produced in a correlated manner in the collision transverse plane.

Hadron properties in chiral sigma model

International Nuclear Information System (INIS)

Shen Hong

2005-01-01

The modification of hadron masses in nuclear medium is studied by using the chiral sigma model, which is extended to generate the omega meson mass by the sigma condensation in the vacuum in the same way as the nucleon mass. The chiral sigma model provides proper equilibrium properties of nuclear matter. It is shown that the effective masses of both nucleons and omega mesons decrease in nuclear medium, while the effective mass of sigma mesons increases oat finite density in the chiral sigma model. The results obtained in the chiral sigma model are compared with those obtained in the Walecka model, which includes sigma and omega mesons in a non-chiral fashion. (author)

Reggeon, Pomeron and Glueball, Odderon-Hadron-Hadron Interaction at High Energies--From Regge Theory to Quantum Chromodynamics

Institute of Scientific and Technical Information of China (English)

XIONG Wen-Yuan; HU Zhao-Hui; WANG Xin-Wen; ZHOU Li-Juan; XIA Li-Xin; MA Wei-Xing

2008-01-01

Based on analysis of scattering matrix S, and its properties such as analyticity, unitarity, Lorentz invariance, and crossing symmetry relation, the Regge theory was proposed to describe hadron-hadron scattering at high energies before the advent of QCD, and correspondingly a Reggeon concept was born as a mediator of strongly interaction. This theory serves as a successful approach and has explained a great number of experimental data successfully, which proves that the Regge theory can be regarded as a basic theory of hadron interaction at high energies and its validity in many applications. However, as new experimental data come out, we have some difficulties in explaining the data. The new experimental total cross section violates the predictions of Regge theory, which shows that Regge formalism is limited in its applications to high energy data. To understand new experimental measurements, a new exchange theory was consequently born and its mediator is called Pomeron, which has vacuum quantum numbers. The new theory named as Pomeron exchange theory which reproduces the new experimental data of diffractive processes successfully. There are two exchange mediators: Reggeon and Pomeron. Reggeon exchange theory can only produce data at the relatively lower energy region, while Pomeron exchange theory fits the data only at higher-energy region, separately. In order to explain the data in the whole energy region, we propose a Reggeon-Pomeron model to describe high-energy hadron-hadron scattering and other diffractive processes. Although the Reggeon-Pomeron model is successful in describing high-energy hadron-hadron interaction in the whole energy region, it is a phenomenological model After the advent of QCD, people try to reveal the mystery of the phenomenological theory from QCD since hadron-hadron processes is a strong interaction, which is believed to be described by QCD. According to this point of view, we study the QCD nature of Reggeon and Pomeron. We claim

NiMax: a new approach to develop hadronic event generators in HEP

International Nuclear Information System (INIS)

Amelin, N.; Komogorov, M.

2000-01-01

The NiMax framework is a new approach to develop, assemble and use hadronic event generators in HEP. There are several important concepts of the NiMax architecture: the components, the data file, the application domain module, the control system and the project. Here we describe these concepts stressing their functionality

A Color Mutation Hadronic Soft Interaction Model -- Eikonal Formalism and Branching Evolution

OpenAIRE

Cao, Zhen

1998-01-01

ECOMB is established as a hadronic multiparticle production generator by soft interaction. It incorporates the eikonal formalism, parton model, color mutation, branching, resonance production and decay. A partonic cluster, being color-neutral initially, splits into smaller color-neutral clusters successively due to the color mutation of the quarks. The process stops at hadronic resonance, $q\\bar q$ pair, formation. The model contains self-similar dynamics and exhibits scaling behavior in the ...

Interacting gluon model for hadron-nucleus and nucleus-nucleus collisions in the central rapidity region

International Nuclear Information System (INIS)

Fowler, G.N.; Navarra, F.S.; Plumer, M.; Lawrence Berkeley Laboratory, Nuclear Science Division, Berkeley, California 94720); Vourdas, A.; Weiner, R.M.

1989-01-01

The interacting gluon model developed to describe the inelasticity distribution in hadron-nucleon collisions has been generalized and applied to hadron-nucleus and nucleus-nucleus interactions. Leading particle spectra and energy distributions in hadron-nucleus and nucleus-nucleus collisions are calculated

New space--time model for hadron--nucleus collisions at high energies

International Nuclear Information System (INIS)

Bialkowski, G.; Chiu, C.B.; Tow, D.M.

1976-12-01

A new space-time model for hadron-nucleus collisions is proposed, where particles at the instant of creation are immature and their maturity rate is enhanced in the presence of other hadronic matter, as in a nucleus. With only one free parameter, the model can explain dn/sub A//sup p//d eta, dn/sub A//sup pi//d eta, R/sub A//sup p/(E/sub L/), and the A-dependences of sigma/sub in/sup pA/ and sigma/sub in/sup pi A/

Atoms and hadrons (Problems of chassification)

International Nuclear Information System (INIS)

Konopel'chenko, B.G.; Rumer, Yu.B.

1979-01-01

A group approach to the classification of two types of physical objects-hadrons and chemical elements, is discussed. Within the framework of this approach hadrons and atoms are considered as stuctureless particles. In the first case, the classification's group is the unitary group SU (3) and in the second one, the orthogonal group O (4). The principles of classification are the same in both cases. It permits to speak about the analogy between atoms and hadrons. Some aspects of this analogy are considered

Hadrons-94

International Nuclear Information System (INIS)

Bugrij, G.; Jenkovsky, L.; Martynov, E.

1994-01-01

These Proceedings contain the contributions to the Workshop HADRONS-94,held in Uzhgorod between September 7-11,1994. They covers the topics: - elastic and diffractive scattering of hadrons and nuclei; -small-x and spin physics; - meson and baryon spectroscopy; - dual and string models; - collective properties of the strongly interacting matter

Hadrons-94

Energy Technology Data Exchange (ETDEWEB)

Bugrij, G; Jenkovsky, L; Martynov, E [eds.

1994-12-31

These Proceedings contain the contributions to the Workshop HADRONS-94,held in Uzhgorod between September 7-11,1994. They covers the topics: - elastic and diffractive scattering of hadrons and nuclei; -small-x and spin physics; - meson and baryon spectroscopy; - dual and string models; - collective properties of the strongly interacting matter.

Low-energy hadronic interactions beyond the current algebra approach

International Nuclear Information System (INIS)

Ivanov, A.N.; Troitskaya, N.I.; Nagy, M.

1993-06-01

The new low-energy AP 3 -interaction, which is produced by convergent box-constituent-quark-loop diagrams, is obtained within chiral perturbation theory at the quark level (CHPT) q with linear realization of chiral U(3) x U(3) symmetry. Its contributions to processes of low-energy interactions of low-lying mesons are investigated. The new interaction goes beyond the framework of the low-energy current algebra approach and of the effective chiral Lagrangians with linear realization of chiral symmetry, constructed at the hadronic level. (author). 17 refs, 3 figs

Effective models of new physics at the Large Hadron Collider

International Nuclear Information System (INIS)

Llodra-Perez, J.

2011-07-01

With the start of the Large Hadron Collider runs, in 2010, particle physicists will be soon able to have a better understanding of the electroweak symmetry breaking. They might also answer to many experimental and theoretical open questions raised by the Standard Model. Surfing on this really favorable situation, we will first present in this thesis a highly model-independent parametrization in order to characterize the new physics effects on mechanisms of production and decay of the Higgs boson. This original tool will be easily and directly usable in data analysis of CMS and ATLAS, the huge generalist experiments of LHC. It will help indeed to exclude or validate significantly some new theories beyond the Standard Model. In another approach, based on model-building, we considered a scenario of new physics, where the Standard Model fields can propagate in a flat six-dimensional space. The new spatial extra-dimensions will be compactified on a Real Projective Plane. This orbifold is the unique six-dimensional geometry which possesses chiral fermions and a natural Dark Matter candidate. The scalar photon, which is the lightest particle of the first Kaluza-Klein tier, is stabilized by a symmetry relic of the six dimension Lorentz invariance. Using the current constraints from cosmological observations and our first analytical calculation, we derived a characteristic mass range around few hundred GeV for the Kaluza-Klein scalar photon. Therefore the new states of our Universal Extra-Dimension model are light enough to be produced through clear signatures at the Large Hadron Collider. So we used a more sophisticated analysis of particle mass spectrum and couplings, including radiative corrections at one-loop, in order to establish our first predictions and constraints on the expected LHC phenomenology. (author)

A Toy Model for QCD: Hadrons, Penta- and Heptaquarks

International Nuclear Information System (INIS)

Nunez, M.; Hess, P.O.; Civitarese, O.; Reboiro, M.

2004-01-01

A toy model for QCD is presented and applied to the hadron spectrum. As a byproduct the structure of penta- and hepta-quarks is obtained. A complete classification of the states is given. One essential feature of the model is the non-conservation of particle number

Hot Strange Hadronic Matter in an Effective Model

Institute of Scientific and Technical Information of China (English)

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

2003-01-01

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

Photon-hadron fragmentation: theoretical situation

International Nuclear Information System (INIS)

Peschanski, R.

1983-07-01

Using a selection of new experimental results models of hadronic fragmentation and their phenomenological comparison are presented. Indeed a convenient theory of hadronic fragmentation -for instance based on Q.C.D.- does not exist: low transverse momentum fragmentation involves the badly known hadronic long-range forces. Models should clarify the situation in the prospect of an eventual future theory

Hadronization of dense partonic matter

Energy Technology Data Exchange (ETDEWEB)

Fries, Rainer J [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2006-12-15

The parton recombination model has turned out to be a valuable tool to describe hadronization in high-energy heavy-ion collisions. I review the model and revisit recent progress in our understanding of hadron correlations. I also discuss higher Fock states in the hadrons, possible violations of the elliptic flow scaling and recombination effects in more dilute systems.

Rapidity and multiplicity correlations in high energy hadronic collisions

International Nuclear Information System (INIS)

Heiselberg, H.

1993-01-01

Rapidity and multiplicity correlations of particle production in high energy hadronic collisions are studied. A simple model including short range correlations in rapidity due to clustering and long range correlations due to energy conservation is able to describe the two-body correlation functions well hadron-nucleon collisions around lab energies of 250 GeV. In this model fractional moments are calculated and compared to data. The strong rise of the factorial moments in rapidity intervals by size δy∝1 can be explained by long and short range correlation alone whereas the factorial moments approach a constant value at very small δy due to lack of correlations also in agreement with experiment. There is therefore no need for introducing intermittency in the particle production in hadronic collisions at these energies. (orig.)

Interacting hadron resonance gas model in the K -matrix formalism

Science.gov (United States)

Dash, Ashutosh; Samanta, Subhasis; Mohanty, Bedangadas

2018-05-01

An extension of hadron resonance gas (HRG) model is constructed to include interactions using relativistic virial expansion of partition function. The noninteracting part of the expansion contains all the stable baryons and mesons and the interacting part contains all the higher mass resonances which decay into two stable hadrons. The virial coefficients are related to the phase shifts which are calculated using K -matrix formalism in the present work. We have calculated various thermodynamics quantities like pressure, energy density, and entropy density of the system. A comparison of thermodynamic quantities with noninteracting HRG model, calculated using the same number of hadrons, shows that the results of the above formalism are larger. A good agreement between equation of state calculated in K -matrix formalism and lattice QCD simulations is observed. Specifically, the lattice QCD calculated interaction measure is well described in our formalism. We have also calculated second-order fluctuations and correlations of conserved charges in K -matrix formalism. We observe a good agreement of second-order fluctuations and baryon-strangeness correlation with lattice data below the crossover temperature.

General method of calculation of any hadronic decay in the 3P0 model

International Nuclear Information System (INIS)

Roberts, W.

1992-01-01

The 3 P 0 pair creation model of hadron decays is generalized to be applicable to the decay of any hadron. The wave function of the decaying hadron is expanded in terms of two clusters. The transition amplitudes is derived for any combination of angular momenta, and for general wave functions in momentum space, expanded in terms of Gaussians times polynomials. (authors)

Microscopic models for hadronic form factors and vertex functions

International Nuclear Information System (INIS)

Santhanam, I.; Bhatnagar, S.; Mitra, A.N.

1990-01-01

We review the status of nucleon (N) and few-nucleon form factors (f.f.'s) from the view-point of a gradual unfolding of successively inner degrees of freedom (d.o.f.) with increase in q 2 . To this end we focus attention on the problem of a microscopic formulation of hadronic vertex functions (v.f.) from the point of view of their key role in understanding the physics of a large variety of few-hadron reactions on the one hand, and their practical usefulness in articulating the internal dynamics of hadron and few-hadron systems on the other hand. The criterion of an integrated view from low-energy spectroscopy to high-q 2 amplitudes is employed to emphasize the desirability of formulations in terms of relativistic dynamical equations based on Lorentz and gauge invariance in preference to phenomenological models, which often require additional assumptions beyond their original premises to extend their applicability domains. In this respect, the practical possibilities of the Bethe-Salpeter equation (BSE) in articulating the necessary dynamical ingredients are emphasized on a two-tier basis, the basis constants (3) being pre-determined from the mass spectral data (1 st stage) in preparation for the construction of the hadron-quark vertex functions (2 nd stage). An explicit construction is outlined for meson-quark and baryon-quark vertex functions as well as of meson-nucleon vertex functions in a stepwise fashion. The role of the latter as basic parameter-free ingredients is discussed for possible use in the more serious treatment in the current literature of quark-meson level (α) and meson-isobar (β) d.o.f. in 2-N and 3-N form factor studies. Since most of these studies are characterized by the use of RGM techniques at the six-quark level, a comparative discussion is also given of several contemporary RGM based models. Finally, the concrete prospects for employing such hardon-quark vertex functions for evaluating pp-bar annihilation amplitudes are briefly indicated

Multiplicity distributions in a thermodynamical model of hadron production in e{sup +}e{sup -} collisions

Energy Technology Data Exchange (ETDEWEB)

Becattini, F. [Florence Univ. (Italy)]|[Istituto Nazionale di Fisica Nucleare, Florence (Italy); Giovannini, A. [Turin Univ. (Italy). Ist. di Fisica Teorica]|[Istituto Nazionale di Fisica Nucleare, Turin (Italy); Lupia, S. [Max-Planck-Institut fuer Physik, Muenchen (Germany). Werner-Heisenberg-Institut

1996-10-01

Predictions of a thermodynamical model of hadron production for multiplicity distributions in e{sup +}e{sup -} annihilations at LEP and PEP-PETRA centre of mass energies are shown. The production process is described as a two-step process in which primary hadrons emitted from the thermal source decay into final observable particles. The final charged track multiplicity distributions turn out to be of negative binomial type and are in quite good agreement with experimental observations. The average number of clans calculated from fitted negative binomial coincides with the average number of primary hadrons predicted by the thermodynamical model, suggesting that clans should be identified with primary hadrons. (orig.)

Hot Strange Hadronic Matter in an Effective Model

Institute of Scientific and Technical Information of China (English)

QIANWei-Liang; SURu-Keng; SONGHong-Qiu

2003-01-01

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

The Mathematical Model High Energy Collisions Process Hadron-Nucleus

International Nuclear Information System (INIS)

Wojciechowski, A.; Strugalska-Gola, E.; Strugalski, Z.

2002-01-01

During the passage high energy hadron by the heavy nucleus emitted are nucleons and many other particles from which most more group are nucleons and mesons π + π - π 0 . in this work we will present the mathematical model which is a simplified description of basic processes in the interior of the nucleus during passing of the hadron by the nucleus. Result of calculations we will compare with experimental results. Experimental data are based on photographs of 180 litre xenon bubble chambers (180 1 KKP) of Institute of Theoretical and Experimental Physics in Moscow (ITEF, Moscow) irradiated with the beam of mesons π - with momentum 3.5 GeV/c. (author)

Multiple production of hadrons at high energies in the model of quark-gluon strings

International Nuclear Information System (INIS)

Kaidalov, A.B.; Ter-Martirosyan, K.A.

1983-01-01

Multiple production of hadrons at high energies is considered in the framework of the approach based on a picture of formation and subsequent fission of the quark-gluon strings, corresponding to the Pomeron with αsub(P)(0) > 1. The topological (1/nsub(f))-expansion and the colour-tube model is used. Inclusive cross-sections are expressed in therms of the structure functions and fragmentation functions of quarks and their limiting values are in an agreement with the results of the reggeon theory. It is pointed out that an account of rapidity fluctuations of the ends of the quark-gluon strings, connected to valence or sea quarks, allows one to explain a number of characteristic features of the multiple production of hadrons. In particular the model, which takes into account multipomeron configurations, reproduces the experimentally observed rise of inclusive spectra in a central region and well describes both rapidity and multiplicity distributions of charged particles up to energies of the SPS-collider. It is shown that in this approach the KNO-scaling is only approximately satisfied and the pattern of its violation at energies √ s approximately 10 3 GeV is predicted. Inclusive spectra are investigated in the whole region 0 or approximately 0.1) Feynman scaling is violated only logarithmically and deviations from it are very rsmall at s 3 +10 4 GeV

Density oscillations within hadrons

International Nuclear Information System (INIS)

Arnold, R.; Barshay, S.

1976-01-01

In models of extended hadrons, in which small bits of matter carrying charge and effective mass exist confined within a medium, oscillations in the matter density may occur. A way of investigating this possibility experimentally in high-energy hadron-hadron elastic diffraction scattering is suggested, and the effect is illustrated by examining some existing data which might be relevant to the question [fr

Nuclear phenomena and the short distance structure of hadrons

International Nuclear Information System (INIS)

Brodsky, S.J.

1979-09-01

In certain cases, nuclear corrections to hadronic phenomena depend in detail on the nature of quark and gluon interactions, as well as the effects of jet development within the nuclear medium. Applications of quantum chromodynamics to fast particle production in nuclear collisions, nuclear form factors, and shadowing in deep inelastic lepton processes are reviewed. Also discussed is a new approach to particle production in hadron-nucleus, nucleus-nucleus and deep-inelastic nuclear reactions from the standpoint of a color-neutralization model. 74 references

Hadron matrix elements of quark operators in the relativistic quark model

Energy Technology Data Exchange (ETDEWEB)

Bando, Masako; Toya, Mihoko [Kyoto Univ. (Japan). Dept. of Physics; Sugimoto, Hiroshi

1979-07-01

General formulae for evaluating matrix elements of two- and four-quark operators sandwiched by one-hadron states are presented on the basis of the relativistic quark model. Observed hadronic quantities are expressed in terms of those matrix elements of two- and four-quark operators. One observes various type of relativistic expression for the matrix elements which in the non-relativistic case reduce to simple expression of the so-called ''the wave function at the origin /sup +/psi(0)/sup +/''.

Track segments in hadronic showers in a highly granular scintillator-steel hadron calorimeter

CERN Document Server

Adloff, C.; Chefdeville, M.; Drancourt, C.; Gaglione, R.; Geffroy, N.; Karyotakis, Y.; Koletsou, I.; Prast, J.; Vouters, G.; Francis, K.; Repond, J.; Schlereth, J.; Smith, J.; Xia, L.; Baldolemar, E.; Li, J.; Park, S.T.; Sosebee, M.; White, A.P.; Yu, J.; Eigen, G.; Mikami, Y.; Watson, N.K.; Mavromanolakis, G.; Thomson, M.A.; Ward, D.R.; Yan, W.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Apostolakis, J.; Dannheim, D.; Dotti, A.; Folger, G.; Ivantchenko, V.; Klempt, W.; Kraaij, E.van der; Lucaci-Timoce, A.-I; Ribon, A.; Schlatter, D.; Uzhinskiy, V.; Cârloganu, C.; Gay, P.; Manen, S.; Royer, L.; Tytgat, M.; Zaganidis, N.; Blazey, G.C.; Dyshkant, A.; Lima, J.G.R.; Zutshi, V.; Hostachy, J.-Y; Morin, L.; Cornett, U.; David, D.; Falley, G.; Gadow, K.; Göttlicher, P.; Günter, C.; Hartbrich, O.; Hermberg, B.; Karstensen, S.; Krivan, F.; Krüger, K.; Lu, S.; Morozov, S.; Morgunov, V.; Reinecke, M.; Sefkow, F.; Smirnov, P.; Terwort, M.; Feege, N.; Garutti, E.; Laurien, S.; Marchesini, I.; Matysek, M.; Ramilli, M.; Briggl, K.; Eckert, P.; Harion, T.; Schultz-Coulon, H.-Ch; Shen, W.; Stamen, R.; Bilki, B.; Norbeck, E.; Onel, Y.; Wilson, G.W.; Kawagoe, K.; Sudo, Y.; Yoshioka, T.; Dauncey, P.D.; Magnan, A.-M; Bartsch, V.; Wing, M.; Salvatore, F.; Gil, E.Cortina; Mannai, S.; Baulieu, G.; Calabria, P.; Caponetto, L.; Combaret, C.; Negra, R.Della; Grenier, G.; Han, R.; Ianigro, J-C; Kieffer, R.; Laktineh, I.; Lumb, N.; Mathez, H.; Mirabito, L.; Petrukhin, A.; Steen, A.; Tromeur, W.; Donckt, M.Vander; Zoccarato, Y.; Alamillo, E.Calvo; Fouz, M.-C; Puerta-Pelayo, J.; Corriveau, F.; Bobchenko, B.; Chadeeva, M.; Danilov, M.; Epifantsev, A.; Markin, O.; Mizuk, R.; Novikov, E.; Popov, V.; Rusinov, V.; Tarkovsky, E.; Kirikova, N.; Kozlov, V.; Smirnov, P.; Soloviev, Y.; Buzhan, P.; Ilyin, A.; Kantserov, V.; Kaplin, V.; Karakash, A.; Popova, E.; Tikhomirov, V.; Kiesling, C.; Seidel, K.; Simon, F.; Soldner, C.; Szalay, M.; Tesar, M.; Weuste, L.; Amjad, M.S.; Bonis, J.; Callier, S.; Lorenzo, S.Conforti di; Cornebise, P.; Doublet, Ph; Dulucq, F.; Fleury, J.; Frisson, T.; der Kolk, N.van; Li, H.; Martin-Chassard, G.; Richard, F.; Taille, Ch de la; Pöschl, R.; Raux, L.; Rouëné, J.; Seguin-Moreau, N.; Anduze, M.; Balagura, V.; Boudry, V.; Brient, J-C; Cornat, R.; Frotin, M.; Gastaldi, F.; Guliyev, E.; Haddad, Y.; Magniette, F.; Musat, G.; Ruan, M.; Tran, T.H.; Videau, H.; Bulanek, B.; Zacek, J.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Ruzicka, P.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Belhorma, B.; Ghazlane, H.; Kotera, K.; Takeshita, T.; Uozumi, S.; Jeans, D.; Götze, M.; Sauer, J.; Weber, S.; Zeitnitz, C.

2013-01-01

We investigate the three dimensional substructure of hadronic showers in the CALICE scintillator-steel hadronic calorimeter. The high granularity of the detector is used to find track segments of minimum ionising particles within hadronic showers, providing sensitivity to the spatial structure and the details of secondary particle production in hadronic cascades. The multiplicity, length and angular distribution of identified track segments are compared to GEANT4 simulations with several different shower models. Track segments also provide the possibility for in-situ calibration of highly granular calorimeters.

Parton dynamics in hadronic processes. Final report

International Nuclear Information System (INIS)

Sukhatme, U.P.

1984-07-01

We have elucidated several aspects of the dual parton fragmentation model for low transverse momentum multiparticle production in hadronic collisions previously developed by the author and collaborators at Orsay, France. In particular, we have verified that the dual parton model correctly reproduces recently obtained two particle inclusive distributions and particle ratios in the central region of pp and anti pp collisions. This work sheds light on the dynamics of partons in a hadronic collision since it strongly indicates that a valence quark from each initial hadron is held back with a small momentum fraction. Also, we have extended the dual parton approach to include diffraction dissocation and studied the consequences on inclusive pion production in pp interactions. We have investigated the virtues and limitations of logarithmic perturbation theory, which is often a much simpler alternative to standard Rayleigh-Schroedinger perturbation theory. Finally, we have developed and studied the shifted 1/N expansion for the enrgy eigenstates in non-relativistic quantum mechanics. Our results provide an accurate, rapidly convergent, powerful new way of handling any spherically symmetric potential. 18 references

Hadron showers in a highly granular calorimeter

International Nuclear Information System (INIS)

Lutz, Benjamin

2010-11-01

A future electron-positron collider like the planned International Linear Collider (ILC) needs excellent detectors to exploit the full physics potential. Different detector concepts have been evaluated for the ILC and two concepts on the particle-flow approach were validated. To make particle-flow work, a new type of imaging calorimeters is necessary in combination with a high performance tracking system, to be able to track the single particles through the full detector system. These calorimeters require an unprecedented level of both longitudinal and lateral granularity. Several calorimeter technologies promise to reach the required readout segmentation and are currently studied. This thesis addresses one of these: The analogue hadron calorimeter technology. It combines work on the technological aspects of a highly granular calorimeter with the study of hadron shower physics. The analogue hadron calorimeter technology joins a classical scintillator-steel sandwich design with a modern photo-sensor technology, the silicon photomultiplier (SiPM). The SiPM is a millimetre sized, magnetic field insensitive, and low cost photo-sensor, that opens new possibilities in calorimeter design. This thesis outlines the working principle and characteristics of these devices. The requirements for an application specific integrated circuit (ASIC) to read the SiPM are discussed; the performance of a prototype chip for SiPM readout, the SPIROC, is quantified. Also the SiPM specific reconstruction of a multi-thousand channel prototype calorimeter, the CALICE AHCAL, is explained; the systematic uncertainty of the calibration method is derived. The AHCAL does not only offer a test of the calorimeter technology, it also allows to record hadron showers with an unprecedented level of details. Test-beam measurements have been performed with the AHCAL and provide a unique sample for the development of novel analysis techniques and the validation of hadron shower simulations. A method to

Hadron showers in a highly granular calorimeter

Energy Technology Data Exchange (ETDEWEB)

Lutz, Benjamin

2010-11-15

A future electron-positron collider like the planned International Linear Collider (ILC) needs excellent detectors to exploit the full physics potential. Different detector concepts have been evaluated for the ILC and two concepts on the particle-flow approach were validated. To make particle-flow work, a new type of imaging calorimeters is necessary in combination with a high performance tracking system, to be able to track the single particles through the full detector system. These calorimeters require an unprecedented level of both longitudinal and lateral granularity. Several calorimeter technologies promise to reach the required readout segmentation and are currently studied. This thesis addresses one of these: The analogue hadron calorimeter technology. It combines work on the technological aspects of a highly granular calorimeter with the study of hadron shower physics. The analogue hadron calorimeter technology joins a classical scintillator-steel sandwich design with a modern photo-sensor technology, the silicon photomultiplier (SiPM). The SiPM is a millimetre sized, magnetic field insensitive, and low cost photo-sensor, that opens new possibilities in calorimeter design. This thesis outlines the working principle and characteristics of these devices. The requirements for an application specific integrated circuit (ASIC) to read the SiPM are discussed; the performance of a prototype chip for SiPM readout, the SPIROC, is quantified. Also the SiPM specific reconstruction of a multi-thousand channel prototype calorimeter, the CALICE AHCAL, is explained; the systematic uncertainty of the calibration method is derived. The AHCAL does not only offer a test of the calorimeter technology, it also allows to record hadron showers with an unprecedented level of details. Test-beam measurements have been performed with the AHCAL and provide a unique sample for the development of novel analysis techniques and the validation of hadron shower simulations. A method to

Fluctuations and correlations in statistical models of hadron production

International Nuclear Information System (INIS)

Gorenstein, M. I.

2012-01-01

An extension of the standard concept of the statistical ensembles is suggested. Namely, the statistical ensembles with extensive quantities fluctuating according to an externally given distribution are introduced. Applications in the statistical models of multiple hadron production in high energy physics are discussed.

Are Hadrons and Nuclei Open Systems ?

International Nuclear Information System (INIS)

Musulmanbekov, G.

1998-01-01

Fulltext We propose to consider the structure of hadrons in the frame of stochastic interpretation of quantum mechanics, or stochastic theory, which is based on classical mechanics in stochastic environment. This environment is associated with subquantal vacuum. Stochastic theory is a classical physics without the hypothesis that there are isolated systems in the universe. It has been shown by some authors that stochastic theory is justified by fractal space-time considerations. In our approach hadron is a set of embedded into stochastic vacuum (SV) valence quarks (VQ) ( quark-antiquark in mesons and three quarks in baryons ) oscillating near center of proper frame of the hadron VQ being placed into SV behaves itself as a dislocation (antidislocation) in solids or vortex ( antivortex ) in liquids. Effective interaction between VQs comes from specific polarization of SV around VQs leading to outside suppression on VQs. Polarization of SV around VQ characterizes the distribution of hardonic matter inside a hadron. Oscillation motion of VQs around the origin, going from their interaction with SV, is strongly correlated. VQs being in equilibrium with SV exchange energy at all times with it. Neighborhood of two or more nucleons changes SV polarization around their VQs in such a way that they tend to occupy the state with minimum energy arrange crystalline like structure. Therefore the behavior of hadrons and nuclei is typical for open systems exchanging energy with environment .In this approach the relation between constituent (nonrelativistic ) quarks and current ( relativistic) ones becomes clear and transparent, because it composes the features of both NRQM and bag models. It gives qualitative and in some cases quantitative description of experimental facts concerning nucleon and nuclear structure searched in scattering experiments. Some proposals and predictions for future experiments are given

Gluon bremstrahlung effects in large P/sub perpendicular/ hadron-hadron scattering

International Nuclear Information System (INIS)

Fox, G.C.; Kelly, R.L.

1982-02-01

We consider effects of parton (primarily gluon) bremstrahlung in the initial and final states of high transverse momentum hadron-hadron scattering. Monte Carlo calculations based on conventional QCD parton branching and scattering processes are presented. The calculations are carried only to the parton level in the final state. We apply the model to the Drell-Yan process and to high transverse momentum hadron-hadron scattering triggered with a large aperture calorimeter. We show that the latter triggers are biased in that they select events with unusually large bremstrahlung effects. We suggest that this trigger bias explains the large cross section and non-coplanar events observed in the NA5 experiment at the SPS

Hadron-hadron potentials from lattice quantum chromodynamics

International Nuclear Information System (INIS)

Rabitsch, K.

1997-10-01

Problems in nuclear physics generally involve several nucleons due to the composite structure of the atomic nucleus. To study such systems one has to solve the Schroedinger equation and therefore has to know a nucleon-nucleon potential. Experimental data and theoretical considerations indicate that nucleons consist of constituent particles, called quarks. Today, Quantum Chromodynamics (QCD) is believed to be the fundamental theory of strong interactions. Consequently, one should try to understand the nucleon-nucleon interaction from first principles of QCD. At nucleonic distances the strong coupling constant is large. Thus, a perturbative treatment of QCD low energy phenomena is not adequate. However, the formulation of QCD on a four-dimensional Euclidean lattice (lattice QCD) makes it possible to address the nonperturbative aspects of the theory. This approach has already produced valuable results. For example, the confinement of quarks in a nucleon has been demonstrated, and hadron masses have been calculated In this thesis various methods to extract the hadron-hadron interactions from first principles of lattice QCD are presented. One possibility is to consider systems of two static hadrons. A comparison of results in pure gluonic vacuum and with sea quarks is given for both the confinement and the deconfinement phase of QCD. Numerical simulations yield attractive potentials in the overlap region of the hadrons for all considered systems. In the deconfinement phase the resulting potentials are shallower reflecting the dissolution of the hadrons. A big step towards the simulation of realistic two-hadron systems on the lattice is the consideration of mesons consisting of dynamic valence quarks. This is done for the two most important fermionic discretization schemes in the pure gluonic vacuum. A calculation in coordinate space utilizing Kogut-Susskind fermions for the valence quarks yields meson-meson potentials with a long ranged interaction, an intermediate

Investigation of the leading and subleading high-energy behavior of hadron-hadron total cross sections using a best-fit analysis of hadronic scattering data

Science.gov (United States)

Giordano, M.; Meggiolaro, E.; Silva, P. V. R. G.

2017-08-01

In the present investigation we study the leading and subleading high-energy behavior of hadron-hadron total cross sections using a best-fit analysis of hadronic scattering data. The parametrization used for the hadron-hadron total cross sections at high energy is inspired by recent results obtained by Giordano and Meggiolaro [J. High Energy Phys. 03 (2014) 002, 10.1007/JHEP03(2014)002] using a nonperturbative approach in the framework of QCD, and it reads σtot˜B ln2s +C ln s ln ln s . We critically investigate if B and C can be obtained by means of best-fits to data for proton-proton and antiproton-proton scattering, including recent data obtained at the LHC, and also to data for other meson-baryon and baryon-baryon scattering processes. In particular, following the above-mentioned nonperturbative QCD approach, we also consider fits where the parameters B and C are set to B =κ Bth and C =κ Cth, where Bth and Cth are universal quantities related to the QCD stable spectrum, while κ (treated as an extra free parameter) is related to the asymptotic value of the ratio σel/σtot. Different possible scenarios are then considered and compared.

Supersymmetric hadronic mechanics and procedures for isosupersymmetrization

International Nuclear Information System (INIS)

Ntibashirakandi, L.; Callebaut, D.K.

1994-01-01

In this paper the authors present the Lie-Santilli lifting of Witten's one-dimensional supersymmetric quantum mechanical model within the context of supersymmetric hadronic mechanics and extended it to three dimensions. They show that the model describes the motion of a spin one-half particle in a central isosuperpotential. Choosing this isosuperpotential within the specific isosupersymmetrization procedure, their theory produces the model of hadronic harmonic oscillator plus isotopic spin-orbit couplings. They finally indicate that their model describes a particle under conventional potentials plus nonlocal-nonhamiltonian corrections expected in deep penetrations of the wavepackets. As such, the model appears to be significant for the recently proposed chemical synthesis of unstable hadrons via lighter hadrons, which is prohibited by quantum mechanics, but permitted by the covering hadronic mechanics. 16 refs

Statistical hadronization and hadronic micro-canonical ensemble II

International Nuclear Information System (INIS)

Becattini, F.; Ferroni, L.

2004-01-01

We present a Monte Carlo calculation of the micro-canonical ensemble of the ideal hadron-resonance gas including all known states up to a mass of about 1.8 GeV and full quantum statistics. The micro-canonical average multiplicities of the various hadron species are found to converge to the canonical ones for moderately low values of the total energy, around 8 GeV, thus bearing out previous analyses of hadronic multiplicities in the canonical ensemble. The main numerical computing method is an importance sampling Monte Carlo algorithm using the product of Poisson distributions to generate multi-hadronic channels. It is shown that the use of this multi-Poisson distribution allows for an efficient and fast computation of averages, which can be further improved in the limit of very large clusters. We have also studied the fitness of a previously proposed computing method, based on the Metropolis Monte Carlo algorithm, for event generation in the statistical hadronization model. We find that the use of the multi-Poisson distribution as proposal matrix dramatically improves the computation performance. However, due to the correlation of subsequent samples, this method proves to be generally less robust and effective than the importance sampling method. (orig.)

Gluonic hadrons

International Nuclear Information System (INIS)

Close, F.E.

1987-09-01

The standard theory of colour forces (Quantum Chromodynamics) suggests that in addition to the familiar hadrons made of quarks, there should exist new states where coloured gluons play an essential dynamical role. The author reviews the theoretical predictions for the properties of these ''glueballs'' and of states containing resonating quarks and gluons. Attempts are made to highlight those features which are common to several models in the literature. Experimental candidates are confronted with the models. No clear cut signal for a gluonic hadron yet exists; consequently what future data are required to determine the constituency of some popular candidates is considered. (author)

Exploring hadronic tau identification with DC1 datat samples a track based approach

CERN Document Server

Richter-Was, Elzbieta; Tarrade, F

2004-01-01

In this note we discuss the identification of hadronic $\\tau$s. We propose an algorithm, tauID, which starts from a reconstructed, relatively high pT track and then collects calorimetric energy deposition in a fixed cone seeded by the track eta and phi at the vertex. With the proposed algorithm we explore exclusive features of the hadronic $\\tau$ decays and we indicate also the possibility of using an energy-flow based approach for defining the energy scale of the reconstructed tau-candidates. The results presented here are limited to the barrel region (|eta| < 1.5) and are based on the DC1 events simulated without pile-up and electronic noise. We compare the performances of the proposed algorithm and of the base-line tauRec algorithm and draw some conclusions for further studies.

Hadron cascades produced by electromagnetic cascades

International Nuclear Information System (INIS)

Nelson, W.R.; Jenkins, T.M.; Ranft, J.

1986-12-01

A method for calculating high energy hadron cascades induced by multi-GeV electron and photon beams is described. Using the EGS4 computer program, high energy photons in the EM shower are allowed to interact hadronically according to the vector meson dominance (VMD) model, facilitated by a Monte Carlo version of the dual multistring fragmentation model which is used in the hadron cascade code FLUKA. The results of this calculation compare very favorably with experimental data on hadron production in photon-proton collisions and on the hadron production by electron beams on targets (i.e., yields in secondary particle beam lines). Electron beam induced hadron star density contours are also presented and are compared with those produced by proton beams. This FLUKA-EGS4 coupling technique could find use in the design of secondary beams, in the determination high energy hadron source terms for shielding purposes, and in the estimation of induced radioactivity in targets, collimators and beam dumps

Total cross sections of hadron interactions at high energies in low constituents number model

International Nuclear Information System (INIS)

Abramovskij, V.A.; Radchenko, N.V.

2009-01-01

We consider QCD hadrons interaction model in which gluons density is low in initial state wave function in rapidity space and real hadrons are produced from color strings decay. In this model behavior of total cross sections of pp, pp bar, π ± p, K ± p, γp, and γγ interactions is well described. The value of proton-proton total cross section at LHC energy is predicted

Hadron masses in a gauge theory

International Nuclear Information System (INIS)

De Rujula, A.; Georgi, H.; Glashow, S.L.

1975-01-01

We explore the implications for hadron spectroscopy of the ''standard'' gauge model of weak, electromagnetic, and strong interactions. The model involves four types of fractionally charged quarks, each in three colors, coupling to massless gauge gluons. The quarks are confined within colorless hadrons by a long-range spin-independent force realizing infrared slavery. We use the asymptotic freedom of the model to argue that for the calculation of hadron masses, the short-range quark-quark interaction may be taken to be Coulomb-like. We rederive many successful quark-model mass relations for the low-lying hadrons. Because a specific interaction and symmetry-breaking mechanism are forced on us by the underlying renormalizable gauge field theory, we also obtain new mass relations. They are well satisfied. We develop a qualitative understanding of many features of the hadron mass spectrum, such as the origin and sign of the Σ-Λ mass splitting. Interpreting the newly discovered narrow boson resonances as states of charmonium, we use the model to predict the masses of charmed mesons and baryons

Hadronic J/psi and charmed particle production and correlating quark rearrangement model

International Nuclear Information System (INIS)

Nishitani, Tadashi

1979-01-01

On the basis of the correlating quark rearrangement model, the exclusive and inclusive production cross sections of J/psi and charmed particles in hadron collisions are calculated. It is shown that the inclusive production cross section of charmed particles is several tens of μb at p sub( l) -- 100 GeV/c in hadron collisions. The OZI rule is discussed in connection with the production mechanism of J/psi particles. (author)

Light hadrons in the bag model with broken chiral symmetry

International Nuclear Information System (INIS)

Efrosinin, V.P.; Zaikin, D.A.

1987-01-01

A version of the bag model with broken chiral symmetry is proposed. A satisfactory description of the experimental data on light hadrons including the pion is obtained. The estimate of the pion-nucleon σ term is given in the framework of this model. The pion and kaon decay constants are calculated. The centre-of-mass motion problem in bag models is discussed

Hadron correlations from recombination

Energy Technology Data Exchange (ETDEWEB)

Fries, Rainer J [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2005-01-01

Quark recombination is a successful model to describe the hadronization of a deconfined quark gluon plasma. Jet-like dihadron correlations measured at RHIC provide a challenge for this picture. We discuss how correlations between hadrons can arise from correlations between partons before hadronization. An enhancement of correlations through the recombination process, similar to the enhancement of elliptic flow is found. Hot spots from completely or partially quenched jets are a likely source of such parton correlations.

Model-independent determination of hadronic neutral-current couplings

International Nuclear Information System (INIS)

Claudson, M.; Paschos, E.A.; Strait, J.; Sulak, L.R.

1979-01-01

Completion of a second generation of experiments on neutrino-induced neutral-current reactions allows a more discriminating study of neutral-current couplings to hadrons. To minimize the sensitivity to model-dependent analyses of inclusive and exclusive pion data, we base our work on measurements of deep-inelastic and elastic reactions alone. Within the regions allowed by the deep-inelastic data for scattering on isoscalar targets, the coupling constants are fit to the q 2 dependence of the neutrino-proton elastic scattering data. This procedure initially yields two solutions for the couplings. One of these, at theta/sub L/ = 55 0 and theta/sub R/ = 205 0 , is predominantly isoscalar and therefore is ruled out by only qualitative consideration of exclusive pion data. The other solution at theta/sub D/ = 140 0 and and theta/sub R/ = 330 0 , is thus a unique determination of the hadronic neutral-current couplings. It coincides with solution A obtained in earlier work, and is insensitive to variations of M/sub A/ within 2 standard deviations of the world average. When constrained to the coupling constants required by the Weinberg-Salam model, the fit agrees with the data to within 1 standard deviation

Workshop on Hadron-Hadron & Cosmic-Ray Interactions at multi-TeV Energies

CERN Document Server

Alessandro, B; Bergman, D; Bongi, M; Bunyatyan, A; Cazon, L; d'Enterria, D; de Mitri, I; Doll, P; Engel, R; Eggert, K; Garzelli, M; Gerhardt, L; Gieseke, S; Godbole, R; Grosse-Oetringhaus, J F; Gustafson, G; Hebbeker, T; Kheyn, L; Kiryluk, J; Lipari, P; Ostapchenko, S; Pierog, T; Piskounova, O; Ranft, J; Rezaeian, A; Rostovtsev, A; Sakurai, N; Sapeta, S; Schleich, S; Schulz, H; Sjostrand, T; Sonnenschein, L; Sutton, M; Ulrich, R; Werner, K; Zapp, K; CRLHC10; CRLHC 10

2011-01-01

The workshop on "Hadron-Hadron and Cosmic-Ray Interactions at multi-TeV Energies" held at the ECT* centre (Trento) in Nov.-Dec. 2010 gathered together both theorists and experimentalists to discuss issues of the physics of high-energy hadronic interactions of common interest for the particle, nuclear and cosmic-ray communities. QCD results from collider experiments -- mostly from the LHC but also from the Tevatron, RHIC and HERA -- were discussed and compared to various hadronic Monte Carlo generators, aiming at an improvement of our theoretical understanding of soft, semi-hard and hard parton dynamics. The latest cosmic-ray results from various ground-based observatories were also presented with an emphasis on the phenomenological modeling of the first hadronic interactions of the extended air-showers generated in the Earth atmosphere. These mini-proceedings consist of an introduction and short summaries of the talks presented at the meeting.

Approach to asymptopia in electron-positron annihilation into hadrons

International Nuclear Information System (INIS)

Choudhury, D.K.

1975-01-01

Assuming CEA/SPEAR energies to be nonasymptotic and from the positivity of the parton mass squared, it is derived that the asymptotic ratio Rsub(infinity) should lie within the interval [6.69+-1.00,7.77+-1.00]. Rsub(infinity) is the limit ratio of the cross sections of the reactions e + e - →hadrons and e + e - →μ + μ - respectively, as s tends to infinity. Present estimate is based on the application of leading-order finite-mass correction to the light-cone algebra/parton model in the non-asymptotic region

Hadron Correlations and Parton Recombination

Energy Technology Data Exchange (ETDEWEB)

Fries, R.J. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)]. E-mail: rjfries@comp.tamu.edu

2007-02-15

Parton recombination has been found to be an extremely useful model to understand hadron production at the Relativistic Heavy Ion Collider. It is particularly important to explore its connections with hard processes. This article reviews some of the aspects of the quark recombination model and places particular emphasis on hadron correlations.

Component-oriented approach to the development and use of numerical models in high energy physics

International Nuclear Information System (INIS)

Amelin, N.S.; Komogorov, M.Eh.

2002-01-01

We discuss the main concepts of a component approach to the development and use of numerical models in high energy physics. This approach is realized as the NiMax software system. The discussed concepts are illustrated by numerous examples of the system user session. In appendix chapter we describe physics and numerical algorithms of the model components to perform simulation of hadronic and nuclear collisions at high energies. These components are members of hadronic application modules that have been developed with the help of the NiMax system. Given report is served as an early release of the NiMax manual mainly for model component users

Highlights from COMPASS in hadron spectroscopy

CERN Document Server

Krinner, Fabian

2015-01-01

Since Quantum Choromdynamics allows for gluon self-coupling, quarks and gluons cannot be observed as free particles, but only their bound states, the hadrons. This so-called confinement phenomenon is responsible for $98\\%$ of the mass in the visible universe. The measurement of the hadron excitation spectra therefore gives valuable input for theory and phenomenology to quantitatively understand this phenomenon. One simple model to describe hadrons is the Constituent Quark Model (CQM), which knows two types of hadrons: mesons, consisting of a quark and an antiquark, and baryons, which are made out of three quarks. More advanced models, which are inspired by QCD as well as calculations within Lattice QCD predict the existence of other types of hadrons, which may be e.g. described solely by gluonic excitations (glueballs) or mixed quark and gluon excitations (hybrids). In order to search for such states, the COMPASS experiment at the Super Proton Synchrotron at CERN has collected large data sets, which allow to ...

Hadronic light-by-light scattering and the muon g −2

International Nuclear Information System (INIS)

Stoffer, P.; Colangelo, G.; Hoferichter, M.; Procura, M.

2015-01-01

The largest uncertainties in the Standard Model calculation of the anomalous magnetic moment of the muon (g − 2) μ come from hadronic contributions. In particular, it can be expected that in a few years the sub leading hadronic light-by-light (HLbL) contribution will dominate the theory uncertainty. We present a dispersive description of the HLbL tensor, which is based on unitarity, analyticity, crossing symmetry, and gauge invariance. Such a model-independent approach opens up an avenue towards a data-driven determination of the HLbL contribution to the (g − 2) μ .

QCD and hadronic strings

International Nuclear Information System (INIS)

Cohen-Tannoudji, G.

1989-01-01

This series of lectures is devoted to review ot he connections between QCD and string theories. One reviews the phenomenological models leading to string pictures in non perturbative QCD and the string effects, related to soft gluon coherence, which arise in perturbative QCD. One tries to build a string theory which goes to QCD at the zero slope limit. A specific model, based on superstring theories is shown to agree with QCD four point amplitudes at the Born approximation and with one loop corrections. One shows how this approach can provide a theoretical framework to account for the phenomenological property of parton-hadron duality.(author)

The calculation of multiquark hadrons by the quark model baryon, meson and multiquark states

International Nuclear Information System (INIS)

Takeuchi, Sachiko; Takizawa, Makoto; Yasui, Shigehiro

2011-01-01

The 1st new hadron summer school related with the new science field, 'the comprehensive research of new hadron states searched by variable flavor number scheme', was held on August 18-20, 2010. This report is one of the 'quark model' lectures. The chapter 1 describes following problems: 1. The background and the significance as a phenomenological theory of the constituent quark model. 2. The introduction of the quark model. 3. The summary of the properties of hadrons in which the quark model can apply to three quarks (qqq) and, one quark and antiquark (q - q) configurations, but is difficult to apply to some configurations. 4. A brief summary of exotic hadrons and recent problems. In chapter 2, the introduction and some exercises of the stochastic variational method are reported as a technique of solving spatial part of multiquark states. In the chapter 3, spins and color parts in multiquark states are calculated. The group theory is applied to calculate the eigenvalues of the Casimir operators of SU(2), SU(3) and SU(6). In the problems of being unable to apply Casimir operators, the direct matrix diagonalization method, m-scheme, is employed for interacting quarks and for the interaction involving quark mass. To find the attractive interaction in tetraquark (QQqq-bar) state is given as an exercise problem. (Y. Kazumata)

Soft hadronic production by ECCO in the geometrical branching model

International Nuclear Information System (INIS)

Pan, J.; Hwa, R.C.

1993-01-01

Soft production of hadrons in hadronic collisions is described in the geometrical branching model and implemented by the eikonal cascade code (ECCO). It is shown that the major global features of multiparticle production can be reproduced by one essential characterization of the dynamics of branching, namely, a scaling law for the mass distribution of daughter clusters. Without further adjustment of any parameters, the event generator can produce local features of multiplicity fluctuations in agreement with the NA22 intermittency data. The scaling exponent ν is determined to be 1.522 at √s =22 GeV, independent of the dimensionality of the intermittency analysis. It is shown that ν is approximately independent of the collision energy

Mach-Like Structure in a Patronic-Hadronic Transport Model at RHIC Energies

International Nuclear Information System (INIS)

Ma, Y.G.; Ma, G.L.; Zhang, S.

2008-01-01

Recent RHIC experimental results indicated an exotic partonic matter may be created in central Au + Au collisions at dollars sqrt (s ( NN))dollars =200 GeV. When a parton with high transverse momentum (jet) passes through the new matter, jet will quench. The lost energy will be redistributed into the medium. Experimentally the soft scattered particles which carry the lost energy have been reconstructed via di-hadron angular correlations of charged particles and a hump structure on away side in di-hadron $ Delta phi$ correlation has been observed in central Au + Au collisions [1,2]. Some interpretations, such as Mach-cone shock wave and gluon Cherenkov-like radiation mechanism etc, have been proposed to explain the splitting behavior of the away side peaks. However, quantitative understanding of the experimental observation has yet to be established. In this work, we use a multi-phase transport (AMPT) model to make a detailed simulation for di-hadron or tri-hadron azimuthal correlation for central Au + Au collisions at dollars sqrt(s ( NN)) dollars =200 GeV. The hump structure on away side (we called Mach-like structure later) in the di-hadron and tri-hadron azimuthal correlations has been observed [3,4,5]. Furthermore, the time evolution of Mach-like structure is presented [6]. With the increasing of the lifetime of partonic matter, Mach-like structure develops by strong parton cascade process. Not only the splitting parameter but also the number of associated hadrons (dollarsN ( h) (assoc)dollars) increases with the lifetime of partonic matter and partonic interaction cross section. Both the explosion of dollarsN ( h) (assoc)dollars following the formation of Mach-like structure and the corresponding results of three-particle correlation support that a partonic Mach-like behavior can be produced by a collective coupling of partons because of the strong parton cascade mechanism. Therefore, the studies about Mach-like structure may give us some critical information

Non-perturbative QCD and hadron physics

International Nuclear Information System (INIS)

Cobos-Martínez, J J

2016-01-01

A brief exposition of contemporary non-perturbative methods based on the Schwinger-Dyson (SDE) and Bethe-Salpeter equations (BSE) of Quantum Chromodynamics (QCD) and their application to hadron physics is given. These equations provide a non-perturbative continuum formulation of QCD and are a powerful and promising tool for the study of hadron physics. Results on some properties of hadrons based on this approach, with particular attention to the pion distribution amplitude, elastic, and transition electromagnetic form factors, and their comparison to experimental data are presented. (paper)

Composite hadrons and relativistic nuclei

International Nuclear Information System (INIS)

Blankenbecler, R.

1978-01-01

Lectures are presented describing a model of hadronic scattering at large momentum transfer, either transverse or longitudinal. This model emphasizes in this regime the importance of forces involving the interchange of constituents of the hadrons, hence its name, the constituent interchange model CIM. The CIM is a rearrangement of standard perturbation theory to take into account the fact that the binding force is very strong in color singlet states (singlet dominance). The hard scattering expansion, incoherence problems, nuclear wave functions and counting rules, interaction between nuclei, pion and proton yields and form factors, structure functions and nonscaling, massive lepton pairs, hadrons at large transverse momentum, and quark-quark scattering are treated. 49 references

Statistical model of hadrons multiple production in space of total angular momentum and isotopic spin

International Nuclear Information System (INIS)

Gridneva, S.A.; Rus'kin, V.I.

1980-01-01

Basic features of the statistical model of multiple hadron production based on microcanonical distribution and taking into account the laws of conservation of total angular momentum, isotopic spin, p-, G-, C-eveness and Bose-Einstein statistics requirements are given. The model predictions are compared with experimental data on anti NN annihilation at rest and e + e - annihilation in hadrons at annihilation total energy from 2 to 3 GeV [ru

Hadronic model for the non-thermal radiation from the binary system AR Scorpii

Science.gov (United States)

Bednarek, W.

2018-05-01

AR Scorpii is a close binary system containing a rotation powered white dwarf and a low-mass M type companion star. This system shows non-thermal emission extending up to the X-ray energy range. We consider hybrid (lepto-hadronic) and pure hadronic models for the high energy non-thermal processes in this binary system. Relativistic electrons and hadrons are assumed to be accelerated in a strongly magnetised, turbulent region formed in collision of a rotating white dwarf magnetosphere and a magnetosphere/dense atmosphere of the M-dwarf star. We propose that the non-thermal X-ray emission is produced either by the primary electrons or the secondary e± pairs from decay of charged pions created in collisions of hadrons with the companion star atmosphere. We show that the accompanying γ-ray emission from decay of neutral pions, which are produced by these same protons, is expected to be on the detectability level of the present and/or the future satellite and Cherenkov telescopes. The γ-ray observations of the binary system AR Sco should allow us to constrain the efficiency of hadron and electron acceleration and also the details of the radiation processes.

Test of hadronic interaction models with the KASCADE-Grande muon data

Directory of Open Access Journals (Sweden)

Schieler H.

2013-06-01

Full Text Available KASCADE-Grande is an air-shower observatory devoted for the detection of cosmic rays with energies in the interval of 1014 – 1018 eV, where the Grande array is responsible for the higher energy range. The experiment comprises different detection systems which allow precise measurements of the charged, electron and muon numbers of extensive air-showers (EAS. These data is employed not only to reconstruct the properties of the primary cosmic-ray particle but also to test hadronic interaction models at high energies. In this contribution, predictions of the muon content of EAS from QGSJET II-2, SIBYLL 2.1 and EPOS 1.99 are confronted with the experimental measurements performed with the KASCADE-Grande experiment in order to test the validity of these hadronic models commonly used in EAS simulations.

Hadronic degrees of freedom in relativistic heavy ion collisions

International Nuclear Information System (INIS)

Otuka, Naohiko; Ohnishi, Akira

2001-01-01

The observation of temperature and transverse expansion velocity between BNL-AGS and CERN-SPS suggests the change of property of hadronic matter. In order to study the origin of the fact, it is important to check whether or not pure hadronic scenarios are excluded. We have discussed the temperature and transverse expansion in relativistic heavy-ion collisions using pure hadronic cascade model, HANDEL. We conclude the hadronic matter in AGS energies are understandable in the frame of the hadronic cascade model if we care how much hadronic degrees of freedom are counted. (author)

Studies on phenomenological hadron models with chiral symmetry

International Nuclear Information System (INIS)

Rathske, E.

1991-12-01

In this report we consider, in the context of phenomenological models for hadrons, several aspects of Skyrme-type and hybrid bag models. In the first of the two central parts we discuss two qualitatively different generalizations of the minimal SU(2) Skyrme model. One of these consists in adding to the Lagrangian density a symmetric term of fourth order in the field derivatives. Its consequences are determined for solutions and observables by analytical and numerical investigations. In the other we propose a contribution for explicit isospin symmetry breaking in the mesonic as well as the baryonic sector. Together with the standard nonlinear σ-model term it allows for exact time-dependent classical soliton solutions. Their quantization leads to a quantitative connection between the hadronic isospin mass differenced of pions and nucleons. The second main part of this report is devoted to the generalization of SU(2) bag models under the aspect of chiral symmetry. We first show that the construction of appropriate surface terms in the Lagrangian density necessitates the introduction of dynamical bosonic degrees of freedom. This allows for a variety of bag scenarios (including the 'endopionic' bag). We then consider explicit isospin symmetry breaking for hybrid bag models with a nonlinear mesonic sector. An intimate relationship is revealed between the effects of a quark mass difference and the time-dependent bosonic solutions found for the purely mesonic case. It is reflected in a nontrivial interdependence between quark and meson masses, bag radius and chiral angle. We provide an especially extensive list of references for the topics discussed in this report. (orig.) [de

Phenomenological studies of hadronic collisions

International Nuclear Information System (INIS)

van Zijl, M.

1987-04-01

Several aspects of hadronic collisions are studied in a phenomenological framework. A Monte Carlo model for initial state parton showers, using a backwards evolution scheme, is presented. Comparisons with experimental data and analytical calculations are made. The consequence of using different fragmentation model on the determination of α s is also investigated. It is found that the different fragmentation models lead to the reconstruction of significantly α s values. Finally the possibility of having several independent parton-parton interactions in a hadron-hadron collision is studied. A model is developed, which takes into account the effects of variable impact parameters. This is implemented in a Monte Carlo computer program and extensive comparisons with experimental data are carried out. There is clear evidence in favour of multiple interactions with variable impact parameters. (author)

Adler function and hadronic contribution to the muon g-2 in a nonlocal chiral quark model

International Nuclear Information System (INIS)

Dorokhov, Alexander E.

2004-01-01

The behavior of the vector Adler function at spacelike momenta is studied in the framework of a covariant chiral quark model with instantonlike quark-quark interaction. This function describes the transition between the high-energy asymptotically free region of almost massless current quarks to the low-energy hadronized regime with massive constituent quarks. The model reproduces the Adler function and V-A correlator extracted from the ALEPH and OPAL data on hadronic τ lepton decays, transformed into the Euclidean domain via dispersion relations. The leading order contribution from the hadronic part of the photon vacuum polarization to the anomalous magnetic moment of the muon, a μ hvp(1) , is estimated

Identifying Multiquark Hadrons from Heavy Ion Collisions

International Nuclear Information System (INIS)

Cho, Sungtae; Furumoto, Takenori; Yazaki, Koichi; Hyodo, Tetsuo; Jido, Daisuke; Ohnishi, Akira; Ko, Che Ming; Lee, Su Houng; Nielsen, Marina; Sekihara, Takayasu; Yasui, Shigehiro

2011-01-01

Identifying hadronic molecular states and/or hadrons with multiquark components either with or without exotic quantum numbers is a long-standing challenge in hadronic physics. We suggest that studying the production of these hadrons in relativistic heavy ion collisions offers a promising resolution to this problem as yields of exotic hadrons are expected to be strongly affected by their structures. Using the coalescence model for hadron production, we find that, compared to the case of a nonexotic hadron with normal quark numbers, the yield of an exotic hadron is typically an order of magnitude smaller when it is a compact multiquark state and a factor of 2 or more larger when it is a loosely bound hadronic molecule. We further find that some of the newly proposed heavy exotic states could be produced and realistically measured in these experiments.

Quark approach to Santilli's conjecture on hadronic structure - II

International Nuclear Information System (INIS)

Animalu, A.O.E.

1982-08-01

In this paper, we continue an earlier investigation of an exactly soluble relativistic Bohr-type model of the internal structure of the proton (three-quark baryon system) and the pion (quark-antiquark meson system), based on a realization of Santilli's conjecture that the hadronic constituents are extended (non-pointlike) objects. The model is abstracted from an expansion of a Yukawa-type potential between the valence quarks and a massive core, in which the meson or gluon exchange term has the effect of reducing the effective Bohr radius for binding to a value less than the radius of the strong charge sphere (or Compton wavelength) of each constituent, so that appreciable overlap of charge volumes occurs, to within a typical distance of order 0.25F or 1/(800 MeV) in qqq-system, and order 1/(1200 MeV) in qq-bar-system, which are comparable to gluon masses, msub(G) approx.= 800 to 1200 MeV, required by the lattice QCD and the MIT Bag Model. Based on the assumptions that the ground state of the proton has 1s 2 2s valence quark configuration, the non-strange quark mass is msub(p)/3, and the dimensionless strong coupling constant of the Yukawa-type potential is g 2 =1, the mass of the proton core is determined self-consistently to be 2470 MeV, exactly balancing the quark binding energy so that the valence quarks appear free. The model correctly predicts the masses of the well-known resonant states of the proton with Jsup(P)=1/2 + as excited states associated with the configuration 1s2s 2 and predicts an upper bound (spectroscopic limit) for the mass of the excited states of the proton in ns 2 ms configuration, as n→infinity and m→infinity, to be 3409 MeV. Based on a generalization of the model to qq-bar-systems, an upper bound (spectroscopic limit) for the mass of qq-bar in ns 2 configuration, as n→infinity, is found to be 3096 MeV, which is the mass of the J/psi-meson. The relation of the model to violation of time-reversal invariance (T-symmetry) by non

Photon transitions between baryons in a new hadron scheme. [Composite model, Dirac spinor

Energy Technology Data Exchange (ETDEWEB)

Sugimoto, H [Kanazawa Inst. of Tech. (Japan); Toya, M

1976-05-01

Photon transitions from the ground state baryon to the nonstrange excited one with L=0, 1 and 2 are investigated. The discussion is based on a new scheme of hadron composite model which takes account of the lower component of the Dirac spinor of constituent particles even in a hadron rest system. There appear generally four independent model amplitudes. Each process ..gamma..+p..-->..B/sub 8/* is described in terms of an individual model amplitude. This helps us to explain the characteristic features of experiment and solve the troubles found in the nonrelativistic scheme. Both magnitudes and signs of predicted amplitudes are shown to be in good agreement with experimental data. From this comparison the specific features of the model amplitudes are found. Discussion is made for higher excited baryons.

FANSY 1.0: a phenomenological model for simulation of coplanar particle generation in superhigh-energy hadron interactions

International Nuclear Information System (INIS)

Mukhamedshin, Rauf

2009-01-01

Simulations show that a phenomenon of coplanarity of most energetic subcores of γ-ray-hadron families found in mountain-based and stratospheric X-ray-emulsion chamber experiments requires to introduce a coplanar particle generation with large transverse momenta in hadron interactions at superhigh energies. Some physical mechanisms are considered. A phenomenological model, which makes it possible to simulate the coplanar particle generation, is presented. Different versions of this model are considered, their features are described and compared with those of models applied by the CORSIKA package. Cosmic-ray experimental data and simulated results are compared. Conclusion on features of hadron interactions at superhigh energies and some predictions with respect to LHC experiments are made. (orig.) 3

Correlations in hadron-nucleus collisions

International Nuclear Information System (INIS)

Wosiek, B.

1976-09-01

The correlations between the particles produced in interactions of hadrons with emulsion nuclei were investigated. The data are in qualitative agreement with the models which describe the interactions with nuclei as subsequent collisions of the fast part of excited hadronic matter inside the nucleus. (author)

Hadronic degrees of freedom in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Otsuka, Naohiko

2001-01-01

Relativistic heavy-ion collisions at AGS energies are studied by using an new developed hadronic cascade model, HANDEL which includes a few hadronic degrees of freedom. The spectra of hadron-hadron, hadron-nucleus and nucleus-nucleus reactions at AGS energies are well reproduced by HANDEL. It is confirmed that the infinite matter described by HANDEL has particle fractions which are expected from grand canonical ensemble. When we compare the thermal evolution of Au+Au collision from HANDEL with the result from JAM which has larger hadronic degree of freedoms, we find both models give similar evolution of temperature, against naive expectation. We argue that this results can be interpretated if the particles in formation time works as the additional effective hadronic degrees of freedom. (author)

Deep-inelastic final states in a space-time description of shower development and hadronization

International Nuclear Information System (INIS)

Ellis, J.

1996-06-01

We extend a quantum kinetic approach to the description of hadronic showers in space, time and momentum space to deep-inelastic ep collisions, with particular reference to experiments at HERA. We follow the history of hard scattering events back to the initial hadronic state and forward to the formation of colour-singlet pre-hadronic clusters and their decays into hadrons. The time evolution of the space-like initial-state shower and the time-like secondary partons are treated similarly, and cluster formation is treated using a spatial criterion motivated by confinement and a non-perturbative model for hadronization. We calculate the time evolution of particle distributions in rapidity, transverse and longitudinal space. We also compare the transverse hadronic energy flow and the distribution of observed hadronic masses with experimental data from HERA, finding encouraging results, and discuss the background to large-rapidity-gap events. The techniques developed in this paper may be applied in the future to more complicated processes such as eA, pp, pA and AA collisions. (orig.)

Hadronic form factors in kaon photoproduction

Energy Technology Data Exchange (ETDEWEB)

Syukurilla, L., E-mail: tmart@fisika.ui.ac.id; Mart, T., E-mail: tmart@fisika.ui.ac.id [Department Fisika, FMIPA, Universitas Indonesia, Depok, 164242 (Indonesia)

2014-09-25

We have revisited the effect of hadronic form factors in kaon photoproduction process by utilizing an isobaric model developed for kaon photoproduction off the proton. The model is able to reproduce the available experimental data nicely as well as to reveal the origin of the second peak in the total cross section, which was the main source of confusion for decades. Different from our previous study, in the present work we explore the possibility of using different hadronic form factors in each of the KΛN vertices. The use of different hadronic form factors, e.g. dipole, Gaussian, and generalized dipole, has been found to produce a more flexible isobar model, which can provide a significant improvement in the model.

Hadronic vs. electromagnetic pulse shape discrimination in CsI(Tl) for high energy physics experiments

Science.gov (United States)

Longo, S.; Roney, J. M.

2018-03-01

Pulse shape discrimination using CsI(Tl) scintillators to perform neutral hadron particle identification is explored with emphasis towards application at high energy electron-positron collider experiments. Through the analysis of the pulse shape differences between scintillation pulses from photon and hadronic energy deposits using neutron and proton data collected at TRIUMF, it is shown that the pulse shape variations observed for hadrons can be modelled using a third scintillation component for CsI(Tl), in addition to the standard fast and slow components. Techniques for computing the hadronic pulse amplitudes and shape variations are developed and it is shown that the intensity of the additional scintillation component can be computed from the ionization energy loss of the interacting particles. These pulse modelling and simulation methods are integrated with GEANT4 simulation libraries and the predicted pulse shape for CsI(Tl) crystals in a 5 × 5 array of 5 × 5 × 30 cm3 crystals is studied for hadronic showers from 0.5 and 1 GeV/c KL0 and neutron particles. Using a crystal level and cluster level approach for photon vs. hadron cluster separation we demonstrate proof-of-concept for neutral hadron detection using CsI(Tl) pulse shape discrimination in high energy electron-positron collider experiments.

Influence of heavy hadronic states on the QCD phase diagram and on the freeze-out within a hadronic chiral model; Einfluss schwerer hadronischer Zustaende auf das QCD-Phasendiagramm und die Ausfrierbedingungen in einem hadronischen chiralen Modell

Energy Technology Data Exchange (ETDEWEB)

Zeeb, G.

2006-07-01

In this thesis the thermodynamical properties of strongly interacting hadronic matter and the microscopic in-medium properties of hadrons are investigated at high temperatures and high baryonic densities within a chiral flavor-SU(3) model. The applied model is a generalized {sigma}-{omega} model in mean-field approximation with baryons and mesons as effective degrees of freedom. It is built on spontaneously broken chiral symmetry and scale invariance. The phase transition behavior is systematically analyzed and is thus shown to depend significantly on the couplings of additional heavier hadronic degrees of freedom. A phase diagram in qualitative agreement with current lattice QCD (lQCD) calculations can result from an according coupling of the lowest lying baryonic decuplet to the model. Alternatively, the coupling of a heavy baryonic test-resonance is investigated, which effectively represents the spectrum of the heavy hadronic states. For a certain range of parameters one can even obtain a phase diagram in quantitative agreement with the lQCD calculations and, simultaneously, a successful description of the ground state properties of nuclear matter. It is shown that (within the model assumptions) the phase transition region is experimentally accessible for the CBM experiment at the upcoming FAIR facility at GSI Darmstadt. The chiral model is further applied to particle yield ratios measured in heavy-ion collisions from AGS, SPS and RHIC. For these investigations parameter sets with strongly differing phase diagrams due to different couplings of the baryon decuplet are used and in addition an ideal hadron gas. At the lower and mid collision energies the chiral parameter sets show an improved description as compared to the ideal hadron gas, especially for parameter sets with phase diagrams similar to the lQCD predictions. The interaction within the chiral model leads to in-medium modifications of the chemical potentials and the hadron masses. Therefore the

Non-perturbative inputs for gluon distributions in the hadrons

International Nuclear Information System (INIS)

Ermolaev, B.I.; Troyan, S.I.

2017-01-01

Description of hadronic reactions at high energies is conventionally done in the framework of QCD factorization. All factorization convolutions comprise non-perturbative inputs mimicking non-perturbative contributions and perturbative evolution of those inputs. We construct inputs for the gluon-hadron scattering amplitudes in the forward kinematics and, using the optical theorem, convert them into inputs for gluon distributions in the hadrons, embracing the cases of polarized and unpolarized hadrons. In the first place, we formulate mathematical criteria which any model for the inputs should obey and then suggest a model satisfying those criteria. This model is based on a simple reasoning: after emitting an active parton off the hadron, the remaining set of spectators becomes unstable and therefore it can be described through factors of the resonance type, so we call it the resonance model. We use it to obtain non-perturbative inputs for gluon distributions in unpolarized and polarized hadrons for all available types of QCD factorization: basic, K_T-and collinear factorizations. (orig.)

Non-perturbative inputs for gluon distributions in the hadrons

Energy Technology Data Exchange (ETDEWEB)

Ermolaev, B.I. [Ioffe Physico-Technical Institute, Saint Petersburg (Russian Federation); Troyan, S.I. [St. Petersburg Institute of Nuclear Physics, Gatchina (Russian Federation)

2017-03-15

Description of hadronic reactions at high energies is conventionally done in the framework of QCD factorization. All factorization convolutions comprise non-perturbative inputs mimicking non-perturbative contributions and perturbative evolution of those inputs. We construct inputs for the gluon-hadron scattering amplitudes in the forward kinematics and, using the optical theorem, convert them into inputs for gluon distributions in the hadrons, embracing the cases of polarized and unpolarized hadrons. In the first place, we formulate mathematical criteria which any model for the inputs should obey and then suggest a model satisfying those criteria. This model is based on a simple reasoning: after emitting an active parton off the hadron, the remaining set of spectators becomes unstable and therefore it can be described through factors of the resonance type, so we call it the resonance model. We use it to obtain non-perturbative inputs for gluon distributions in unpolarized and polarized hadrons for all available types of QCD factorization: basic, K{sub T}-and collinear factorizations. (orig.)

Digital Hadron Calorimetry

Science.gov (United States)

Bilki, Burak

2018-03-01

The Particle Flow Algorithms attempt to measure each particle in a hadronic jet individually, using the detector providing the best energy/momentum resolution. Therefore, the spatial segmentation of the calorimeter plays a crucial role. In this context, the CALICE Collaboration developed the Digital Hadron Calorimeter. The Digital Hadron Calorimeter uses Resistive Plate Chambers as active media and has a 1-bit resolution (digital) readout of 1 × 1 cm2 pads. The calorimeter was tested with steel and tungsten absorber structures, as well as with no absorber structure, at the Fermilab and CERN test beam facilities over several years. In addition to conventional calorimetric measurements, the Digital Hadron Calorimeter offers detailed measurements of event shapes, rigorous tests of simulation models and various tools for improved performance due to its very high spatial granularity. Here we report on the results from the analysis of pion and positron events. Results of comparisons with the Monte Carlo simulations are also discussed. The analysis demonstrates the unique utilization of detailed event topologies.

Nuclear symmetry energy in density dependent hadronic models

International Nuclear Information System (INIS)

Haddad, S.

2008-12-01

The density dependence of the symmetry energy and the correlation between parameters of the symmetry energy and the neutron skin thickness in the nucleus 208 Pb are investigated in relativistic Hadronic models. The dependency of the symmetry energy on density is linear around saturation density. Correlation exists between the neutron skin thickness in the nucleus 208 Pb and the value of the nuclear symmetry energy at saturation density, but not with the slope of the symmetry energy at saturation density. (author)

Behaviour of hadron matter within the bag model: Pt. 2

International Nuclear Information System (INIS)

Auberson, G.; Savatier, F.

1988-01-01

On the basis of the quantum theory of the vibrating bag developed in I, it is worked out the partition function of a gas of hadronic bags. This is done within the small deformation, Van der Waals approximation. The outcome is in full agreement with a previous, less elaborate model of deconfinement phase transition

Physics at hadron colliders: Experimental view

International Nuclear Information System (INIS)

Siegrist, J.L.

1987-08-01

The physics of the hadron-hadron collider experiment is considered from an experimental point of view. The problems encountered in determination of how well the standard model describes collider results are discussed. 53 refs., 58 figs

Elastic diffraction interactions of hadrons at high energies

International Nuclear Information System (INIS)

Ismatov, E.I.; Ubaev, J.K.; Tshay, K.V.; Zholdasova, S.M.; Juraev, Sh.Kh.; Essaniazov, Sh.P.

2006-01-01

Full text: 1. The diffraction theory of elastic and inelastic scattering of hadron-hadron and hadron-nucleus processes is developed. The description of experimental data on differential cross section of elastic scattering p p, p-bar p in wide range of transferred momentum is made in the frames of the developed inelastic overlap function model. The investigation of nuclei elastic scattering at the low, middle and high energies is carried out, that allowed to execute quantitative control of efficiency or quantum-field and phenomenological theories and make critical analysis of their utility. The principle of construction of realistic amplitudes of the elastic scattering is confirmed on the basic of the s- and t-channel approaches both conditions stationary of amplitudes. For a wide range of models the comparative analysis of amplitude of inelastic scattering in representation of impact parameter is executed. The expression for effective radius of interaction, effective trajectory Regge and slope of inelastic function of overlapping are analysed. In diffraction approximation the satisfactory description of the data on hadrons interaction at the energy of tens GeV with proton and deuterons is received. The features of spectra of fast particles are analysed. The theory of collective variables S, T, P which characterize a deviation degree of angular distribution of particles from spherical symmetry, the general formula for dispersion of any density of obtained, the particles decays are investigated [1-2]. 2. The solution of Lippmann-Schwinger equation investigated within the frameworks of frameworks of high -energy approximation satisfies the generalized Huygens principle used in the diffraction theory nuclear processes. The diffraction emission is considered at the interaction of charged hadrons one with another and the nuclei [3]. 3. Study of elastic interactions of hadrons at high energies is of great interest due to the fact that the amplitude of this process is the

Hadronization of the quark-gluon plasma

International Nuclear Information System (INIS)

Mueller, B.; Sano, M.; Sato, H.; Schaefer, A.

1986-11-01

We construct a model for hadronization of the quark-gluon plasma, based on the relativistic coalescence model. We relate the coalescence amplitude to the one-particle Wigner function for quarks in the plasma. The relation between the Wigner function and the nucleon structure function is pointed out. We derive explicit expressions for the production of mesons and baryons in the framework of the relativistic harmonic oscillator model of hadronic structure. (author)

Reevaluation of the hadronic vacuum polarisation contributions to the Standard Model predictions of the muon g-2 and α(m{sub Z}{sup 2}) using newest hadronic cross-section data

Energy Technology Data Exchange (ETDEWEB)

Davier, M.; Zhang, Z. [IN2P3-CNRS et Universite Paris-Sud 11, Laboratoire de l' Accelerateur Lineaire, Orsay (France); Hoecker, A. [CERN, Geneva (Switzerland); Malaescu, B. [IN2P3-CNRS et Universites Pierre-et-Marie-Curie et Denis-Diderot, Laboratoire de Physique Nucleaire et des Hautes Energies, Paris (France)

2017-12-15

We reevaluate the hadronic vacuum polarisation contributions to the muon magnetic anomaly and to the running of the electromagnetic coupling constant at the Z-boson mass. We include newest e{sup +}e{sup -} → hadrons cross-section data (among others) from the BABAR and VEPP-2000 experiments. For the muon (g-2)/2 we find for the lowest-order hadronic contribution (693.1 ± 3.4) x 10{sup -10}, improving the precision of our previous evaluation by 21%. The full Standard Model prediction differs by 3.5σ from the experimental value. The five-quark hadronic contribution to α(m{sub Z}{sup 2}) is evaluated to be (276.0 ± 0.9) x 10{sup -4}. (orig.)

Physics at Future Hadron Colliders

CERN Document Server

Baur, U.; Parsons, J.; Albrow, M.; Denisov, D.; Han, T.; Kotwal, A.; Olness, F.; Qian, J.; Belyaev, S.; Bosman, M.; Brooijmans, G.; Gaines, I.; Godfrey, S.; Hansen, J.B.; Hauser, J.; Heintz, U.; Hinchliffe, I.; Kao, C.; Landsberg, G.; Maltoni, F.; Oleari, C.; Pagliarone, C.; Paige, F.; Plehn, T.; Rainwater, D.; Reina, L.; Rizzo, T.; Su, S.; Tait, T.; Wackeroth, D.; Vataga, E.; Zeppenfeld, D.

2001-01-01

We discuss the physics opportunities and detector challenges at future hadron colliders. As guidelines for energies and luminosities we use the proposed luminosity and/or energy upgrade of the LHC (SLHC), and the Fermilab design of a Very Large Hadron Collider (VLHC). We illustrate the physics capabilities of future hadron colliders for a variety of new physics scenarios (supersymmetry, strong electroweak symmetry breaking, new gauge bosons, compositeness and extra dimensions). We also investigate the prospects of doing precision Higgs physics studies at such a machine, and list selected Standard Model physics rates.

Hadron seagulls and parton jets

International Nuclear Information System (INIS)

Satz, H.; Zarmi, Y.

1976-01-01

For the lepton production of hadrons in the current fragmentation region it was recently shown that the two-level partonic picture leads to a broadening of the average transverse momentum of the observed secondaries. This ''seagull'' effect is well known for hadron-hadron interactions. In the note it is considered the possibility that parton arguments can explain it here as well and it is discussed what information on the constituent structure of hadrons can be obtained through an investigation of the seagull effect from such a point of view. It is shown that a non trivial seagull effect is a consequence of a simple two step production mechanism and the parton model predicts significant differences between baryon, meson and virtual-photon fragmentation seagull

Hadron correlations from recombination and fragmentation

Energy Technology Data Exchange (ETDEWEB)

Fries, Rainer J [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2005-04-01

We review the formalism of quark recombination applied to the hadronization of a quark-gluon plasma. Evidence in favour of the quark recombination model is outlined. Recent work on parton correlations, leading to detectable correlations between hadrons, is discussed. Hot spots from completely quenched jets are a likely source of such correlations which appear to be jet like. It will be discussed how such a picture compares with measurement of associated hadron yields at RHIC.

Revision of the high energy hadronic interaction models PHOJET/DPMJET-III

CERN Document Server

Fedynitch, A

2015-01-01

The high-energy hadronic interaction model DPMJET-III is responsible for simulating nuclear interactions in the particle simulation package FLUKA. On the level of individual nucleon interactions it employs PHOJET, which provides sophisticated forward physics and diffraction models. This paper summarizes some of the recent developments, in particular regarding minimum-bias physics at the LHC, which apply to DPMJET-III and PHOJET at the same time.

Anisotropic superfluidity of hadronic matter

International Nuclear Information System (INIS)

Chela Flores, J.

1977-10-01

From a model of strong interactions with important general features (f-g model) and from recent experiments of Rudnick and co-workers on thin films of helium II, hadronic matter is considered as a new manifestation of anisotropic superfluidity. In order to test the validity of the suggestion, some qualitative features of multiparticle production of hadrons are considered, and found to have a natural explanation. A prediction is made following a recent experiment on π + p collisions

Current Status of Exotic Hadrons

International Nuclear Information System (INIS)

Saeed, M.A.; Ahmed, Maqsood; Fazal-e-Aleem

2005-01-01

Physics of exotic hadrons is in the limelight these days. The models for these baryons are discussed as well as their production and decay processes and methods of their identification. The results of recent experiments in this field are presented, in which some unusual states are observed. These states are candidates for exotic hadrons

Deep-inelastic final states in a space-time description of shower development and hadronization

International Nuclear Information System (INIS)

Ellis, J.; Geiger, K.; Kowalski, H.

1996-01-01

We extend a quantum kinetic approach to the description of hadronic showers in space, time, and momentum space to deep-inelastic ep collisions, with particular reference to experiments at DESY HERA. We follow the history of hard scattering events back to the initial hadronic state and forward to the formation of color-singlet prehadronic clusters and their decays into hadrons. The time evolution of the spacelike initial-state shower and the timelike secondary partons are treated similarly, and cluster formation is treated using a spatial criterion motivated by confinement and a nonperturbative model for hadronization. We calculate the time evolution of particle distributions in rapidity, transverse, and longitudinal space. We also compare the transverse hadronic energy flow and the distribution of observed hadronic masses with experimental data from HERA, finding encouraging results, and discuss the background to large-rapidity-gap events. The techniques developed in this paper may be applied in the future to more complicated processes such as eA, pp, pA, and AA collisions. copyright 1996 The American Physical Society

Broken chiral symmetry and the structure of hadrons

International Nuclear Information System (INIS)

Spence, W.L.

1982-01-01

The spontaneous breaking of chiral symmetry plays a decisive role in the structure of hadrons composed of light quarks. The formalism by which the dynamics of chiral symmetry breaking and its implications for hadronic structure can be explored in a simplified world in which fully relativistic zero-bare-mass quarks interact through a chirally symmetric instantaneous confining potential is presented. By thus modeling the essentials of the chiral limit-N/sub c/ infinity limit of QCD contact is made with the successes of existent semiphenomenological models of hadrons but post assumptions which explicitly violate chiral symetry are avoided. This revised approach then makes possible a unification of the dynamics of hadron structure with the mechanism of spontaneous chiral breaking and guarantees the appearance of the correct Goldstone excitations. The chiral breaking order parameter (absolute value anti psi psi), effective quark mass, and Goldstone boson wave function are obtainable by solving a single non-linear integral equation once a potential has been prescribed. The stability of the chiral asymmetric vacuum must then be established by studying the linear eigenvalue problem which determines the spectrum of states with vacuum quantum numbers. The nature of the instability of the chiral symmetric vacuum that leads to spontaneous symmetry breaking is explained and its apparent contingency on details of the dynamics is emphasized. It is argued that a single massless fermion in a chirally symmetric potential does form bound states for which a semi-classical description is given. Coupling to vacuum pairs of such bound states occasions the possibility of chiral symmetry breakdown

High energy hadron spin-flip amplitude

International Nuclear Information System (INIS)

Selyugin, O.V.

2016-01-01

The high-energy part of the hadron spin-flip amplitude is examined in the framework of the new high-energy general structure (HEGS) model of the elastic hadron scattering at high energies. The different forms of the hadron spin-flip amplitude are compared in the impact parameter representation. It is shown that the existing experimental data of the proton-proton and proton-antiproton elastic scattering at high energy in the region of the diffraction minimum and at large momentum transfer give support in the presence of the energy-independent part of the hadron spin-flip amplitude with the momentum dependence proposed in the works by Galynskii-Kuraev. [ru

Signatures of Parton Exogamy in e+ e- -> W+ W- -> hadrons

OpenAIRE

Ellis, John; Geiger, Klaus

1997-01-01

We propose possible signatures of `exogamous' combinations between partons in the different W+ and W- hadron showers in e+e- -> W+W- events with purely hadronic final states. Within the space-time model for hadronic shower development that we have proposed previously, we find a possible difference of about 10 % between the mean hadronic multiplicity in such purely hadronic final states and twice the hadronic multiplicity in events in which one W decays hadronically and the other leptonically,...

Charge distributions and correlations in fragmentation models for soft hadron collisions

International Nuclear Information System (INIS)

Wolf, E.A. de

1984-01-01

Data on charge distributions and charge correlations in pp and meson-proton interactions at PS and SPS energies are successfully compared with the Lund fragmentation model for low-psub(T) hadron collisions. It is argued that local conservation of quantum numbers and resonance production, as implemented in fragmentation models, are sufficient ingredients to explain most of the available experimental results at these energies. No necessity is found for dual-sheet contributions considered in DTU-based parton models. (orig.)

Determination of freeze-out conditions from fluctuations in the Hadron Resonance Gas model

International Nuclear Information System (INIS)

Alba, P; Alberico, W; Sarti, V Mantovani; Ratti, C; Bellwied, R; Bluhm, M; Nahrgang, M

2015-01-01

Fluctuations of conserved charges measured in Heavy-Ion Collisions (HICs) received increasing attention in recent years, because they are good candidates to explore the phase diagram of QCD matter. During the last year, net-electric charge and net-proton moments of multiplicities measured at RHIC have been published by the STAR collaboration, for a range of collision energies which spans a region of the phase diagram at finite chemical potential. Here we present a new freeze-out curve obtained using the Hadron Resonance Gas (HRG) model approach to fit these experimental data. The HRG model is modified in order to have a realistic description of the HICs: kinematic cuts, resonance feed-down and resonance regeneration are taken into account. Our result is in agreement with preliminary studies by the ALICE collaboration, and is supported by a recent lattice analysis of the same quantities. (paper)

QCD in hadron-hadron collisions

International Nuclear Information System (INIS)

Albrow, M.

1997-03-01

Quantum Chromodynamics provides a good description of many aspects of high energy hadron-hadron collisions, and this will be described, along with some aspects that are not yet understood in QCD. Topics include high E T jet production, direct photon, W, Z and heavy flavor production, rapidity gaps and hard diffraction

Very high multiplicity hadron processes

International Nuclear Information System (INIS)

Mandzhavidze, I.; Sisakyan, A.

2000-01-01

The paper contains a description of a first attempt to understand the extremely inelastic high energy hadron collisions, when the multiplicity of produced hadrons considerably exceeds its mean value. Problems with existing model predictions are discussed. The real-time finite-temperature S-matrix theory is built to have a possibility to find model-free predictions. This allows one to include the statistical effects into consideration and build the phenomenology. The questions to experiment are formulated at the very end of the paper

Distribution over pT of direct secondary ha drons in hadron-hadron and hadron-nucleus collisions

International Nuclear Information System (INIS)

Braun, V.M.

1986-01-01

Transverse momentum distributions of direct secondary hadrons produced in proton, pion and kaon collisons with nucleons and nuclei are calculated in the additive quark model. Results of calculations are compared to the experimental data on production of neutral strange particles

The deconfinement phase transition, hadronization and the NJL model

International Nuclear Information System (INIS)

Raha, Sibaji

2000-01-01

One of the confident predictions of QCD is that at sufficiently high temperature and/or density, hadronic matter should undergo a thermodynamic phase transition to a color deconfined state of matter-popularly called the Quark-Gluon Plasma (QGP). In low energy effective theories of Quantum Chromodynamics (QCD), one usually talks of the chiral transition for which a well defined order parameter exists. We investigate the dissociation of pions and kaons in a medium of hot quark matter described by the Nambu-Jona Lasinio (NJL) model. The decay widths of pion and kaon are found to be large but finite at temperature much higher than the critical temperature for the chiral (or deconfinement) transition, the kaon decay width being much larger. Thus pions and even kaons (with a lower density compared to pions) may coexist with quarks and gluons at such high temperatures. On the basis of such premises, we investigate the process of hadronization in quark-gluon plasma with special emphasis on whether such processes shed any light on acceptable low energy effective theories of QCD

SU(2 color NJL model and EOS of quark-hadron matter at finite temperature and density

Directory of Open Access Journals (Sweden)

Weise Wolfram

2012-02-01

Full Text Available We study the NJL model with the Polyakov loop in the SU(2-color case for the EOS of quark-hadron matter at finite temperature and density. We consider the spontaneous chiral symmetry breaking and the diquark condensation together with the behavior of the Polyakov loop for the phase diagram of quark-hadron matter. We discuss the spectrum of mesons and diquark baryons (boson at finite temperature and density.We derive also the linear sigma model Lagrangian for diquark baryon and mesons.

Hadron spectrum in quenched lattice QCD and quark potential models

International Nuclear Information System (INIS)

Iwasaki, Y.; Yoshie, T.

1989-01-01

We show that the quenched lattice QCD gives a hadron spectrum which remarkably agrees with that of quark potential models for quark mass m q ≥ m strange , even when one uses the standard one-plaquette gauge action. This is contrary to what is stated in the literature. We clarify the reason of the discrepancy, paying close attention to systematic errors in numerical calculations. (orig.)

Large transverse momenta phenomena in hadron-hadron collisions

International Nuclear Information System (INIS)

McCubbin, N.A.

1981-05-01

The production of particles with large transverse momentum in high energy hadron-hadron collisions is reviewed. The emphasis is placed on the experimental results. These results are discussed in terms of present theoretical ideas on interactions between hadronic constituents, but no attempt is made to review the theoretical work in a comprehensive manner. (author)

Di-hadron correlations with identified leading hadrons in 200 GeV Au + Au and d + Au collisions at STAR

Science.gov (United States)

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

2015-12-01

The STAR Collaboration presents for the first time two-dimensional di-hadron correlations with identified leading hadrons in 200 GeV central Au + Au and minimum-bias d + Au collisions to explore hadronization mechanisms in the quark gluon plasma. The enhancement of the jet-like yield for leading pions in Au + Au data with respect to the d + Au reference and the absence of such an enhancement for leading non-pions (protons and kaons) are discussed within the context of a quark recombination scenario. The correlated yield at large angles, specifically in the ridge region, is found to be significantly higher for leading non-pions than pions. The consistencies of the constituent quark scaling, azimuthal harmonic model and a mini-jet modification model description of the data are tested, providing further constraints on hadronization.

Hadron production in photon-photon collisions

International Nuclear Information System (INIS)

Pandita, P.N.; Singh, Y.

1976-01-01

We analyze deep-inelastic photon-photon collisions via the two-photon mechanism in electron-positron (-electron) colliding beams in a form especially suitable for experimental analysis. It is shown that by a helicity analysis similar to that used in electroproduction experiments, we can separate five of the eight structure functions describing the process γ* + γ* → hadrons. The helicity cross sections for this process and for the process with one real photon (inelastic electron-photon scattering) are related to structure functions, and are evaluated using quark light-cone algebra. There are anomalous contributions to the structure functions for the inelastic electron-photon scattering which arise both in parton as well as generalized vector-meson-dominance models. This suggests a connection between these two types of models for photon-photon scattering. Further, we use vector-meson dominance to construct a sum rule for sigma/sub gamma//sub gamma/ /sub arrow-right/ from which it is estimated that roughly 20% of the cross section should be built up from higher-mass vector states. Using a spectral representation for the total transverse cross section, and the ''aligned-jet'' vector-dominance model we achieve a connection, via a ''correspondence principle,'' with the parton model for the hadron multiplicities in photon-photon collisions. We also comment on inclusive pion multiplicities and the approach to scaling for photon-photon processes in the light-cone algebra

Hadron production at RHIC: recombination of quarks

Energy Technology Data Exchange (ETDEWEB)

Fries, Rainer J [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2005-01-01

We discuss quark recombination applied to the hadronization of a quark gluon plasma. It has been shown that the quark recombination model can explain essential features of hadron production measured in high energy heavy ion collisions.

The influence of fragmentation models on the determination of the strong coupling constant in e+e- annihilation into hadrons

International Nuclear Information System (INIS)

Behrend, H.J.; Chen, C.; Fenner, H.; Schachter, M.J.; Schroeder, V.; Sindt, H.; D'Agostini, G.; Apel, W.D.; Banerjee, S.; Bodenkamp, J.; Chrobaczek, D.; Engler, J.; Fluegge, G.; Fries, D.C.; Fues, W.; Gamerdinger, K.; Hopp, G.; Kuester, H.; Mueller, H.; Randoll, H.; Schmidt, G.; Schneider, H.; Boer, W. de; Buschhorn, G.; Grindhammer, G.; Grosse-Wiesmann, P.; Gunderson, B.; Kiesling, C.; Kotthaus, R.; Kruse, U.; Lierl, H.; Lueers, D.; Oberlack, H.; Schacht, P.; Colas, P.; Cordier, A.; Davier, M.; Fournier, D.; Grivaz, J.F.; Haissinski, J.; Journe, V.; Klarsfeld, A.; Laplanche, F.; Le Diberder, F.; Mallik, U.; Veillet, J.J.; Field, J.H.; George, R.; Goldberg, M.; Grossetete, B.; Hamon, O.; Kapusta, F.; Kovacs, F.; London, G.; Poggioli, L.; Rivoal, M.; Aleksan, R.; Bouchez, J.; Carnesecchi, G.; Cozzika, G.; Ducros, Y.; Gaidot, A.; Jadach, S.; Lavagne, Y.; Pamela, J.; Pansart, J.P.; Pierre, F.

1983-01-01

Hadronic events obtained with the CELLO detector at PETRA were compared with first-order QCD predictions using two different models for the fragmentation of quarks and gluons, the Hoyer model and the Lund model. Both models are in reasonable agreement with the data, although they do not completely reproduce the details of many distributions. Several methods have been applied to determine the strong coupling constant αsub(s). Although within one model the value of αsub(s) varies by 20% among the different methods, the values determined using the Lund model are 30% or more larger (depending on the method used) than the values determined with the Hoyer model. Our results using the Hoyer model are in agreement with previous results based on this approach. (orig.)

Analyticity in a phenomenology of electro-weak structure of hadrons

International Nuclear Information System (INIS)

Dubnicka, S.; Dubnickova, A. Z.

2010-01-01

The utility of an application of the analyticity in a phenomenology of electro-weak structure of hadrons is demonstrated in a number of obtained new and experimentally verifiable results. With this aim first the problem of an inconsistency of the asymptotic behavior of vector-meson-dominance model with the asymptotic behavior of form factors of baryons and nuclei is solved generally and a general approach for determination of the lowest normal and anomalous singularities of form factors from the corresponding Feynman diagrams is reviewed. Then many useful applications by making use of the analytic properties of electro-weak form factors and amplitudes of various electromagnetic processes of hadrons are carried out. (Author)

Hot Strange Hadronic Matter in an Effective Model

Science.gov (United States)

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

2003-10-01

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

Hadron collider physics 2005. Proceedings

International Nuclear Information System (INIS)

Campanelli, M.; Clark, A.; Wu, X.

2006-01-01

The Hadron Collider Physics Symposia (HCP) are a new series of conferences that follow the merger of the Hadron Collider Conferences with the LHC Symposia series, with the goal of maximizing the shared experience of the Tevatron and LHC communities. This book gathers the proceedings of the first symposium, HCP2005, and reviews the state of the art in the key physics directions of experimental hadron collider research: - QCD physics - precision electroweak physics - c-, b-, and t-quark physics - physics beyond the Standard Model - heavy ion physics The present volume will serve as a reference for everyone working in the field of accelerator-based high-energy physics. (orig.)

anti ee annihilation into hadrons from dual unitarisation

International Nuclear Information System (INIS)

Hong-mo, C.

1976-09-01

By grafting to the dual unitarisation scheme for hadron reactions a quark-current coupling suggested by the parton model, a model is obtained for anti ee annihilations in which the conversion of quarks into final hadrons is specific. As a first application, the correction to the value of R given by the parton model is estimated. (author)

Leptoproduction of nuclei as an analogue to production in hadron-hadron interactions (at the example of J/psi)

International Nuclear Information System (INIS)

Batunin, A.V.; Smirnov, A.Yu.

1985-01-01

The role of states with hidden colour inside a nucleus in leptoproduction processes (at the example of J/psi-meson) production is investigated. A concrete production mechanism is proposed, appealing to the dual parton model of hadron-hadron interactions. Comparison with experiment is made

Di-hadron correlations with identified leading hadrons in 200 GeV Au+Au and d+Au collisions at STAR

Directory of Open Access Journals (Sweden)

L. Adamczyk

2015-12-01

Full Text Available The STAR Collaboration presents for the first time two-dimensional di-hadron correlations with identified leading hadrons in 200 GeV central Au+Au and minimum-bias d+Au collisions to explore hadronization mechanisms in the quark gluon plasma. The enhancement of the jet-like yield for leading pions in Au+Au data with respect to the d+Au reference and the absence of such an enhancement for leading non-pions (protons and kaons are discussed within the context of a quark recombination scenario. The correlated yield at large angles, specifically in the ridge region, is found to be significantly higher for leading non-pions than pions. The consistencies of the constituent quark scaling, azimuthal harmonic model and a mini-jet modification model description of the data are tested, providing further constraints on hadronization.

Di-hadron correlations with identified leading hadrons in 200 GeV Au + Au and d + Au collisions at STAR

Energy Technology Data Exchange (ETDEWEB)

Adamczyk, L; Adkins, JK; Agakishiev, G; Aggarwal, MM; Ahammed, Z; Alekseev, I; Aparin, A; Arkhipkin, D; Aschenauer, EC; Averichev, GS; Bai, X; Bairathi, V; Banerjee, A; Bellwied, R; Bhasin, A; Bhati, AK; Bhattarai, P; Bielcik, J; Bielcikova, J; Bland, LC; Bordyuzhin, IG; Bouchet, J; Brandenburg, D; Brandin, AV; Bunzarov, I; Butterworth, J; Caines, H; Calderón de la Barca Sánchez, M; Campbell, JM; Cebra, D; Cervantes, MC; Chakaberia, I; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, X; Chen, JH; Cheng, J; Cherney, M; Christie, W; Contin, G; Crawford, HJ; Das, S; De Silva, LC; Debbe, RR; Dedovich, TG; Deng, J; Derevschikov, AA; di Ruzza, B; Didenko, L; Dilks, C; Dong, X; Drachenberg, JL; Draper, JE; Du, CM; Dunkelberger, LE; Dunlop, JC; Efimov, LG; Engelage, J; Eppley, G; Esha, R; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Federic, P; Fedorisin, J; Feng, Z; Filip, P; Fisyak, Y; Flores, CE; Fulek, L; Gagliardi, CA; Garand, D; Geurts, F; Gibson, A; Girard, M; Greiner, L; Grosnick, D; Gunarathne, DS; Guo, Y; Gupta, S; Gupta, A; Guryn, W; Hamad, A; Hamed, A; Haque, R; Harris, JW; He, L; Heppelmann, S; Heppelmann, S; Hirsch, A; Hoffmann, GW; Hofman, DJ; Horvat, S; Huang, T; Huang, B; Huang, HZ; Huang, X; Huck, P

2015-10-23

The STAR Collaboration presents for the first time two-dimensional di-hadron correlations with identified leading hadrons in 200 GeV central Au + Au and minimum-bias d + Au collisions to explore hadronization mechanisms in the quark gluon plasma. The enhancement of the jet-like yield for leading pions in Au + Au data with respect to the d + Au reference and the absence of such an enhancement for leading non-pions (protons and kaons) are discussed within the context of a quark recombination scenario. The correlated yield at large angles, specifically in the ridge region, is found to be significantly higher for leading non-pions than pions. The consistencies of the constituent quark scaling, azimuthal harmonic model and a mini-jet modification model description of the data are tested, providing further constraints on hadronization.

Hadronic tau decays and QCD

CERN Document Server

Hocker, Andreas

1997-01-01

We present new results for the r hadronic spectral functions analysis using data accumulated by the ALEPH detector at LEP during the years 1991-94. The vector and the axial-vector spectral functions are determined from their respective unfolded, i.e., physical invariant mass spectra. The r vector and axial-vector hadronic widths and certain spectral moments are exploited to measure a, and nonperturbative contributions at the r mass scale. The best, and experimentally and theoretically most robust, determination of a,(Mr) is obtained from the inclusive (V + A) fit that yields a,(Mr) = 0.349 ± 0.018 giving a,(Mz) = 0.1 212 ± 0.0022 after the evolution to the mass of the Z boson. The approach of the Operator Product Expansion (OPE) is tested experimentally by means of an evolution of the r hadronic width to masses smaller than the r mass.

New method of fast simulation for a hadron calorimeter response

International Nuclear Information System (INIS)

Kul'chitskij, Yu.; Sutiak, J.; Tokar, S.; Zenis, T.

2003-01-01

In this work we present the new method of a fast Monte-Carlo simulation of a hadron calorimeter response. It is based on the three-dimensional parameterization of the hadronic shower obtained from the ATLAS TILECAL test beam data and GEANT simulations. A new approach of including the longitudinal fluctuations of hadronic shower is described. The obtained results of the fast simulation are in good agreement with the TILECAL experimental data

UCLA space-time area law model: A persuasive foundation for hadronization

International Nuclear Information System (INIS)

Abachi, S.; Buchanan, C.; Chien, A.; Chun, S.; Hartfiel, B.

2007-01-01

From the studies of rates and distributions of heavy quark (c,b) mesons we have developed additional evidence that hadron formation, at least in the simplest environment of e + e - collisions, is dominantly controlled by a space-time area law (''STAL''), an approach suggested by both non-perturbative QCD and relativistic string models. From the dynamics of heavy quarks whose classical space-time world-lines deviate significantly from the light-cone, we report the exact calculation of the relevant space-time area and the derivation of a Lorentz invariant variable, z eff , which reduces to the light-cone momentum fraction z for low mass quarks. Using z eff in the exponent of our fragmentation function in place of z, we find persuasive agreement with L=0,1 charmed and bottom meson data as well as for u,d,s L=0 states. Presuming STAL to be a valid first-order description for all these meson data, we find the scale of other possible second-order effects to be limited to ∝20% or less of the observed rates. The model favors a b-quark mass of ∝4.5 GeV. (orig.)

Quark-hadron duality in meson physics

International Nuclear Information System (INIS)

Anisovich, V.V.

1994-01-01

Quark hadron dualism is discussed, based on observing the changes in the quark model characteristics after the inclusion into hadron degrees of freedom. A standard version of the potential model is presented. The potential which is responsible for the formation of mesons may be divided into two pieces: a short-range part for distances about 0.3 - 0.5 fm and a long-range part at distances more than 1 fm. (R.P.). 5 refs., 2 figs

Quark-hadron duality in meson physics

Energy Technology Data Exchange (ETDEWEB)

Anisovich, V.V. [Petersburg Nuclear Physics Inst., Gatchina (Russian Federation)

1994-12-31

Quark hadron dualism is discussed, based on observing the changes in the quark model characteristics after the inclusion into hadron degrees of freedom. A standard version of the potential model is presented. The potential which is responsible for the formation of mesons may be divided into two pieces: a short-range part for distances about 0.3 - 0.5 fm and a long-range part at distances more than 1 fm. (R.P.). 5 refs., 2 figs.

Hadron static properties in the model considering the structure of QCD vacuum

International Nuclear Information System (INIS)

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

1987-01-01

The model taking into account the interaction of quarks with QCD vacuum fields is applied to calculate the mean-square charge radii, magnetic moments and axial-vector constants of the hadron interaction. It is shown that one-particle contributions of these characteristics describe the experimental data with 20% accuracy

Hadron interactions

International Nuclear Information System (INIS)

Fischer, J.; Kolar, P.; Kundrat, V.

1988-01-01

The proceedings contain invited lectures and papers presente at the symposium. Attention was devoted to hadron interactions a high energy in QCD, to the structure and decay of hadrons, the production of hadrons and supersymmetric particles in e + e - and ep collisions, to perturbation theory in quantum field theory, and new supersymmetric extensions of relativistic algebra. (Z.J

Head-On Beam-Beam Interactions in High-Energy Hadron Colliders. GPU-Powered Modelling of Nonlinear Effects

CERN Document Server

AUTHOR|(CDS)2160109; Støvneng, Jon Andreas

2017-08-15

The performance of high-energy circular hadron colliders, as the Large Hadron Collider, is limited by beam-beam interactions. The strength of the beam-beam interactions will be higher after the upgrade to the High-Luminosity Large Hadron Collider, and also in the next generation of machines, as the Future Circular Hadron Collider. The strongly nonlinear force between the two opposing beams causes diverging Hamiltonians and drives resonances, which can lead to a reduction of the lifetime of the beams. The nonlinearity makes the effect of the force difficult to study analytically, even at first order. Numerical models are therefore needed to evaluate the overall effect of different configurations of the machines. For this thesis, a new code named CABIN (Cuda-Accelerated Beam-beam Interaction) has been developed to study the limitations caused by the impact of strong beam-beam interactions. In particular, the evolution of the beam emittance and beam intensity has been monitored to study the impact quantitatively...

Hadron production from a boiling quark soup

International Nuclear Information System (INIS)

Bohr, H.; Nielsen, H.B.

1977-01-01

A thermodynamical quark model is presented which can predict cross sections for particle production in hadronic interactions at high energies. In this model a hadronic collision gives rise to a soup of quarks and antiquarks at some temperature kT approximately 170 MeV. Results for inclusive meson production cross sections look promising in comparison with experiments. A formula for the inclusive cross section is given. (Auth.)

The influence of strong decay on the spectra of hadrons

International Nuclear Information System (INIS)

Beveren, E.J.H. van.

1983-01-01

At present, the theory of strong interactions cannot make use of perturbative calculations. For that reason, non-perturbative methods have been proposed recently in the quark model. The author shows that a geometrical model provides an adequate description of quark confinement in hadrons and of the mass spectrum by means of exactly-solvable equations. The properties which these models must possess, are obtained from phenomenological hadron models. First, the influence of hadronic decay on the properties of hadrons is discussed. Next, a numerical method for solving a coupled-channel Schroedinger equation is presented. The author deals with coupling constants, transition potentials, radial spectra and hadronic decay widths of light and heavy mesons. The spectra and strong decay of charmonium and beautonium are investigated and theoretically described using quarks in a de Sitter geometry. A conformal Lagrangian is constructed which describes quark confinement in an anti-de Sitter geometry by spontaneous symmetry breaking of the conformal Lagrangian. (G.J.P.)

Nuclear ``pasta'' phase within density dependent hadronic models

Science.gov (United States)

Avancini, S. S.; Brito, L.; Marinelli, J. R.; Menezes, D. P.; de Moraes, M. M. W.; Providência, C.; Santos, A. M.

2009-03-01

In the present paper, we investigate the onset of the “pasta” phase with different parametrizations of the density dependent hadronic model and compare the results with one of the usual parametrizations of the nonlinear Walecka model. The influence of the scalar-isovector virtual δ meson is shown. At zero temperature, two different methods are used, one based on coexistent phases and the other on the Thomas-Fermi approximation. At finite temperature, only the coexistence phases method is used. npe matter with fixed proton fractions and in β equilibrium are studied. We compare our results with restrictions imposed on the values of the density and pressure at the inner edge of the crust, obtained from observations of the Vela pulsar and recent isospin diffusion data from heavy-ion reactions, and with predictions from spinodal calculations.

Nuclear 'pasta' phase within density dependent hadronic models

International Nuclear Information System (INIS)

Avancini, S. S.; Marinelli, J. R.; Menezes, D. P.; Moraes, M. M. W. de; Brito, L.; Providencia, C.; Santos, A. M.

2009-01-01

In the present paper, we investigate the onset of the 'pasta' phase with different parametrizations of the density dependent hadronic model and compare the results with one of the usual parametrizations of the nonlinear Walecka model. The influence of the scalar-isovector virtual δ meson is shown. At zero temperature, two different methods are used, one based on coexistent phases and the other on the Thomas-Fermi approximation. At finite temperature, only the coexistence phases method is used. npe matter with fixed proton fractions and in β equilibrium are studied. We compare our results with restrictions imposed on the values of the density and pressure at the inner edge of the crust, obtained from observations of the Vela pulsar and recent isospin diffusion data from heavy-ion reactions, and with predictions from spinodal calculations

The differences in hadronic cross-sections and the residues of secondary reggeons in the quark-gluon model for strong interactions

International Nuclear Information System (INIS)

Kaidalov, A.B.; Volkovitsky, P.E.

1981-01-01

In the framework of the quark-gluon picture for strong interactions based on the topological expansion and the string model, the relations between t differences of hadronic cross- section are obtained. The system of equations for the contribution of secondary reggeons (rho, ω, f, A 2 and phi and f' poles) to the elastic scattering amplitudes for arbitrary hadrons is derived. It is shown that this system has a factorized solution and the secondary reggeon residues for all hadrons are expressed in terms of the universal function g(t). The model predictions are in a good agreement with experimental data [ru

Hadron-hadron colliders

International Nuclear Information System (INIS)

Month, M.; Weng, W.T.

1983-01-01

The objective is to investigate whether existing technology might be extrapolated to provide the conceptual framework for a major hadron-hadron collider facility for high energy physics experimentation for the remainder of this century. One contribution to this large effort is to formalize the methods and mathematical tools necessary. In this report, the main purpose is to introduce the student to basic design procedures. From these follow the fundamental characteristics of the facility: its performance capability, its size, and the nature and operating requirements on the accelerator components, and with this knowledge, we can determine the technology and resources needed to build the new facility

New approach to nonleptonic weak interactions. I. Derivation of asymptotic selection rules for the two-particle weak ground-state-hadron matrix elements

International Nuclear Information System (INIS)

Tanuma, T.; Oneda, S.; Terasaki, K.

1984-01-01

A new approach to nonleptonic weak interactions is presented. It is argued that the presence and violation of the Vertical BarΔIVertical Bar = 1/2 rule as well as those of the quark-line selection rules can be explained in a unified way, along with other fundamental physical quantities [such as the value of g/sub A/(0) and the smallness of the isoscalar nucleon magnetic moments], in terms of a single dynamical asymptotic ansatz imposed at the level of observable hadrons. The ansatz prescribes a way in which asymptotic flavor SU(N) symmetry is secured levelwise for a certain class of chiral algebras in the standard QCD model. It yields severe asymptotic constraints upon the two-particle hadronic matrix elements of nonleptonic weak Hamiltonians as well as QCD currents and their charges. It produces for weak matrix elements the asymptotic Vertical BarΔIVertical Bar = 1/2 rule and its charm counterpart for the ground-state hadrons, while for strong matrix elements quark-line-like approximate selection rules. However, for the less important weak two-particle vertices involving higher excited states, the Vertical BarΔIVertical Bar = 1/2 rule and its charm counterpart are in general violated, providing us with an explicit source of the violation of these selection rules in physical processes

Medium energy hadron-nucleus scattering in the 1/N expansion formalism

International Nuclear Information System (INIS)

Kuyucak, S.; Morrison, I.

1992-01-01

The algebraic-eikonal approach to the medium energy hadron-nucleus scattering is generalized to arbitrary interactions and boson types using the 1/N expansion technique for the interacting boson model. The results are used in a comparative study of proton scattering from deformed nuclei in the sd and sdg boson models. The two models give almost identical results for a pure quadrupole interaction but widely differ when a hexadecapole interaction is included. 25 refs., 3 tabs., 7 figs

Strange particles from dense hadronic matter

International Nuclear Information System (INIS)

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

1996-01-01

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

Ericson fluctuations in hadron scattering

International Nuclear Information System (INIS)

Frautschi, S.

1975-01-01

It is shown that there are resonances with high mass and long lives, at the very least, longer than the 10 -23 second transit time across a hadron. The theoretical and then the experimental approaches to this problem are described

Fixed target hadron production measurements

CERN Document Server

Panman, J

2009-01-01

The knowledge of light hadron production cross-sections in proton-nucleus interactions is an important prerequisite to the analysis of a wide variety of experiments. One of the important limiting factors for the precision of accelerator based and atmospheric neutrino oscillation experiments is the uncertainty in the composition and spectrum of the neutrino flux. Cosmic-ray experiments detecting extensive air-showers can greatly improve their ability to interpret the data when precise hadron production spectra are available over a large range of energies. Dedicated hadron production experiments have been taking data recently and are now publishing their results. Other experiments have just started their data-taking and plan to supply measurements which can significantly extend the kinematic range in which data will be available. Early measurements at the LHC can extend this range to much higher energies than available up to now. Recent results will be shown and compared with hadronic production models. An outl...

Quantum chromodynamic quark model study of hadron and few hadron systems. Technical report, 1990--1996

International Nuclear Information System (INIS)

Ji, C.R.

1999-01-01

This report details research progress and results obtained during the entire period of the research project. In compliance with grant requirements the Principal Investigator, Professor Chueng-Ryong Ji, has conducted a research program addressing theoretical investigations of hadron structure and reactions using quantum chromodynamic quark models. This Principal Investigator has devoted 50% of his time during the academic year and 100% of his time in the summer. This percent effort has continued during the entire period of the grant. The new, significant research results are briefly summarized in this report. Finally, full, detailed descriptions of completed work can be found in the project publications which are listed at the end of this technical report

Constraints on hadronically decaying dark matter

Energy Technology Data Exchange (ETDEWEB)

Garny, Mathias [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ibarra, Alejandro [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Tran, David [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Minnesota Univ., Minneapolis, MN (United States). School of Physics and Astronomy

2012-05-15

We present general constraints on dark matter stability in hadronic decay channels derived from measurements of cosmic-ray antiprotons.We analyze various hadronic decay modes in a model-independent manner by examining the lowest-order decays allowed by gauge and Lorentz invariance for scalar and fermionic dark matter particles and present the corresponding lower bounds on the partial decay lifetimes in those channels. We also investigate the complementarity between hadronic and gamma-ray constraints derived from searches for monochromatic lines in the sky, which can be produced at the quantum level if the dark matter decays into quark-antiquark pairs at leading order.

Constraints on hadronically decaying dark matter

International Nuclear Information System (INIS)

Garny, Mathias; Ibarra, Alejandro; Tran, David; Minnesota Univ., Minneapolis, MN

2012-05-01

We present general constraints on dark matter stability in hadronic decay channels derived from measurements of cosmic-ray antiprotons.We analyze various hadronic decay modes in a model-independent manner by examining the lowest-order decays allowed by gauge and Lorentz invariance for scalar and fermionic dark matter particles and present the corresponding lower bounds on the partial decay lifetimes in those channels. We also investigate the complementarity between hadronic and gamma-ray constraints derived from searches for monochromatic lines in the sky, which can be produced at the quantum level if the dark matter decays into quark-antiquark pairs at leading order.

Heavy ion and hadron reactions in emulsion

International Nuclear Information System (INIS)

Otterlund, I.

1979-04-01

Recent results from heavy ion and hadron reactions in emulsion are reviewed. General properties of hadron-reaction multiplicities and their correlation to the production of recoiling protons are given. Properties of pseudo-rapidity distributions of shower-particles especially the particle production in the central region of pseudo-rapidity will be discussed. Non-peripheral heavy ion reactions are compared to recent participant-spectator model calculations. Very energetic cosmic ray events will be examined in the light of recent results from hadron-nucleus reactions. (author)

Hadron form factors in the constituent quark model

International Nuclear Information System (INIS)

Cardarelli, F.; Salme', G.; Simula, S.; Pace, E.

1998-01-01

Hadron electromagnetic form factors are evaluated in a light-front constituent quark model based on the eigenfunctions of a mass operator, including in the q-q interaction a confining term and a one-gluon-exchange term (OGE). The spin-dependent part of the interaction plays an essential role for obtaining both a proper fit of the experimental nucleon electromagnetic form factors and the faster than dipole decrease of the magnetic N-P 33 (1232) transition form factor. The effects of the D wave, produced by the tensor part of the OGE interaction, on the quadrupole and Coulomb N-P 33 (1232) transition form factors have been found to be negligible. (author)

Hadronic cascade processes

International Nuclear Information System (INIS)

Ilgenfritz, E.M.; Kripfganz, J.; Moehring, H.J.

1977-01-01

The analytical treatment of hadronic decay cascades within the framework of the statistical bootstrap model is demonstrated on the basis of a simple variant. Selected problems for a more comprehensive formulation of the model such as angular momentum conservation, quantum statistical effects, and the immediate applicability to particle production processes at high energies are discussed in detail

Computing the hadronic vacuum polarization function by analytic continuation

Energy Technology Data Exchange (ETDEWEB)

Feng, Xu [KEK National High Energy Physics, Tsukuba (Japan); Hashimoto, Shoji [KEK National High Energy Physics, Tsukuba (Japan); The Graduate Univ. for Advanced Studies, Tsukuba (Japan). School of High Energy Accelerator Science; Hotzel, Grit [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; Petschlies, Marcus [The Cyprus Institute, Nicosia (Cyprus); Renner, Dru B. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

2013-07-15

We propose a method to compute the hadronic vacuum polarization function on the lattice at continuous values of photon momenta bridging between the space-like and time-like regions. We provide two independent derivations of this method showing that it leads to the desired hadronic vacuum polarization function in Minkowski space-time. We show with the example of the leading- order QCD correction to the muon anomalous magnetic moment that this approach can provide a valuable alternative method for calculations of physical quantities where the hadronic vacuum polarization function enters.

Hadron final states in deep inelastic processes

International Nuclear Information System (INIS)

Bjorken, J.D.

1976-05-01

Lectures are presented dealing mainly with the description and discussion of hadron final states in electroproduction, colliding beams, and neutrino reactions from the point of view of the simple parton model. Also the space-time evolution of final states in the parton model is considered. It is found that the picture of space-time evolution of hadron final states in deep inelastic processes isn't totally trivial and that it can be made consistent with the hypotheses of the parton model. 39 references

Hadron component of families (exp. 'Pamir' III)

International Nuclear Information System (INIS)

Anon.

1984-01-01

Possibilities of nuclear interaction investigation at 10 15 - 10 16 ev by means of analysis of family hadron component, registered in carbon and deep lead x-ray emulsion chambers, are discussed. The paper is divided in three parts. General properties of hadron families are discribed and compared in C and Pb chambers (part I). Correlations between gamma and hadron components of families are studied in the part II. It is shown that fluctuations of energies of this component are wider than in usually used models of nuclear interactions. The ratio of single hadron flux to the flux of γ-families is connected with cross-section and energy dissipation of nuclear interactions at about 10 16 ev (part III). (author)

Dynamical and Bose-Einstein correlations in hadronization

International Nuclear Information System (INIS)

Scholten, O.; Wu, H.C.

1993-01-01

Pion correlations in the hadronization process are studied. A distinction is made between 'dynamical', due to the mechanism of the fragmentation scheme, and Bose-Einstein correlations, due to the statistics. It is found that in a string hadronization model not based on the usage of fragmentation functions, the dynamical correlations are at least as important as statistical correlation for identical charged pions. Other correlation functions are dominated by resonance decay. The importance of dynamical correlations imply that a pure chaotic assumption for the hadronization process is not applicable and thus that observed correlations should not be interpreted as measuring the spatial and temporal extent of sources. Comparisons are made with data from hadronic (e + , e - ) annihilation. (orig.)

Heavy quark correlations in hadronic collisions

International Nuclear Information System (INIS)

Mangano, M.L.; Ridolfi, G.

1992-01-01

The study of heavy quark production at hadron colliders will provide important tests and measurements within and possibly beyond the Standard Model. The results of a recent calculation of heavy quark hadronic production correlation properties at the full next-to-leading order (NLO) in perturbative QCD are presented. These properties are important for several applications. (R.P.) 8 refs.; 3 figs

The influence of fragmentation models in the production of hadron ...

Indian Academy of Sciences (India)

The analysis of electron–positron annihilations to hadrons at high energies shows that apart from two-jet events, there are also signs of three-jet events which are interpreted according to the QCD, as a gluon radiated by a quark. In this paper, we investigate the fragmentation of quarks and gluons to hadron jets. We show ...

Inelasticity in hadron-nucleus collisions in the geometrical two-chain model

International Nuclear Information System (INIS)

Wibig, T.; Sobczynska, D.

1995-01-01

Two features of great importance registered in experiments on hadron-nucleus collisions are the decreased inelasticity and multiplicity in intranucleus collisions. In this paper we show that such behaviour is a natural consequence of the geometrical two-chain model of multi-particle production processes: only the forward-going chain can undergo secondary interactions in the nucleus. A quantitative comparison with the data is presented. (author)

The Brief Life of a Hadron: QCD unquenched

International Nuclear Information System (INIS)

Pennington, Michael R.

2015-03-01

Once upon a time, the picture of hadrons was of mesons made of a quark and an antiquark, and baryons of three quarks. Though hadrons heavier than the ground states inevitably decay by the strong interaction, the successes of the quark model might suggest their decays are a mere perturbation. However, Eef van Beveren, whose career we celebrate here, recognised that decays are an integral part of the life of a hadron. The channels into which they decay are often essential to their very existence. These hold the secrets of strong coupling QCD and teach us the way quarks really build hadrons.

The importance of the measurement of ρ for the understanding of the high energy hadron-hadron scattering

International Nuclear Information System (INIS)

Gauron, P.; Nicolescu, B.

1992-06-01

It is shown both on general and phenomenological grounds, why the ρ-parameter (the ratio of the real over the imaginary part of the forward hadron amplitude) is the most suitable one for exploring Odderon effects in the present energy range. An almost model-independent analysis of the experimental data by taking into account the analytical constraints and the assumption of maximality is performed. Using the maximal Odderon approach as a guide, the following constrain at √s= 546 GeV is established: ρ ( p-bar) p pp T >σ p -bar p T relation exists. (R.P.) 14 refs., 3 figs

Connections between lepton-induced and hadron-induced multiparticle reactions

International Nuclear Information System (INIS)

Brodsky, S.J.; Gunion, J.F.

1976-01-01

Jet production is studied as a link between hadron- and lepton-induced reactions and interpreted in terms of models of underlying quark dynamics. We discuss how fragmentation distributions, quantum number flow, the charged-momentum vector, and quark counting rules can discriminate among various possible jet structures. We also review recent work on the possible relationship of the rising hadron multiplicity to quark confinement and color gauge theories. A number of new tests of quark models in hadron, photon, and lepton collisions are discussed. (orig.) [de

Left-right asymmetry in neutrino-produced hadron jets

International Nuclear Information System (INIS)

Ballagh, H.C.; Bingham, H.H.; Lawry, T.J.; Lys, J.; Lynch, G.R.; Sokoloff, M.D.; Stevenson, M.L.; Huson, F.R.; Schmidt, E.; Smart, W.; Treadwell, E.; Cence, R.J.; Harris, F.A.; Jones, M.D.; Koide, A.; Peters, M.W.; Peterson, V.Z.; Lubatti, H.J.; Moriyasu, K.; Wolin, E.

1989-01-01

In an experiment (E546) to study interactions of left-angle E right-angle=100 GeV and left-angle Q 2 right-angle=17 GeV 2 neutrinos in the Fermilab 15-foot bubble chamber, we have looked for a left-right asymmetry in the azimuthal angle φ of individual hadrons about the direction of the lepton momentum transfer (q vector). Significant asymmetry is found for forward positive hadrons; for x F >0.10, we find left-angle cosφ right-angle=-0.029±0.008, where x F is the Feynman x variable. Negative hadrons with x F >0.10 show no asymmetry, left-angle cosφ right-angle=0.004±0.011. A model which includes parton intrinsic transverse momentum k t reproduces the asymmetry of combined positive and negative hadrons with x F >0.10, left-angle cosφ right-angle=-0.018±0.0065, if left-angle k t 2 right-angle=0.065±0.024 GeV 2 /c 2 . But the model predicts almost equal asymmetries for positive and negative hadrons. The model also agrees poorly with the observed dependence on the kinematic variables x and Q 2 if the k t distribution is assumed to be independent of kinematic variables

Gluonium candidates from hadronic and e+e- interactions

International Nuclear Information System (INIS)

Heusch, C.A.

1985-12-01

The experimental approaches exploited in the search for gluonia that are deemed most promising are briefly described, both in hadron-hadron collisions and heavy quarkonium decay. The presently available evidence is summarized for those states that have been claimed as possible gluonia. Proceeding in the order of lowest-mass expectation, categorization is done only in terms of definitive (or putative) J/sup PC/ assignments. 51 refs., 16 figs., 3 tabs

Hadronic collision and hadronic structure (an experimental review)

International Nuclear Information System (INIS)

Davier, M.

1975-01-01

In this set of lectures an attempt is made to present a survey of the available experimental data on hadronic collisions at large transverse momentum, together with their current phenomenological descriptions. In particular, the experimental confirmation of constituent structure is looked at in a critical way. The emphasis throughout is to let the data speak in the most unbiased way and to gather evidence as to the short range structure of the hadronic interactions. Finally the current information on lepton production in hadronic collisions is reviewed

Signatures of Parton Exogamy in $e^+ e^- \\to W^+ W^- \\to$ hadrons

CERN Document Server

Ellis, Jonathan Richard; Ellis, John; Geiger, Klaus

1997-01-01

We propose possible signatures of `exogamous' combinations between partons in the different W+ and W- hadron showers in e+e- -> W+W- events with purely hadronic final states. Within the space-time model for hadronic shower development that we have proposed previously, we find a possible difference of about 10 % between the mean hadronic multiplicity in such purely hadronic final states and twice the hadronic multiplicity in events in which one W decays hadronically and the other leptonically, i.e., \

On hadronic production of the Bc meson

International Nuclear Information System (INIS)

Chang Chaohsi; Chen Yuqi; Han Guoping; Jiang Hongtao

1994-08-01

Various approaches to the hadronic productions of the double heavy meson B c are investigated in this paper. The resultant cross sections obtained by the approaches are compared with in several aspects. One may see that the differences are quite substantial. The advantages and shortcomings of the approaches are discussed. (author). 17 refs, 4 figs

The role of hadron resonances in hot hadronic matter

Energy Technology Data Exchange (ETDEWEB)

Goity, Jose [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hampton Univ., Hampton, VA (United States)

2017-02-01

Hadron resonances can play a significant role in hot hadronic matter. Of particular interest for this workshop are the contributions of hyperon resonances. The question about how to quantify the effects of resonances is here addressed. In the framework of the hadron resonance gas, the chemically equilibrated case, relevant in the context of lattice QCD calculations, and the chemically frozen case relevant in heavy ion collisions are discussed.

On the hadron formation time in pion-nucleus interaction

International Nuclear Information System (INIS)

Bravina, L.V.; Korotkikh, V.L.; Sarycheva, L.I.; Sivoklokov, S.Yu.

1992-01-01

Differences in the observable characteristics of pion-nucleus interactions at high energy are investigated for two definitions of the hadron formation time. The Monte Carlo simulation of hadron-nucleus interactions and quark-gluon string model for hadron-hadron collisions are used. It is shown that the momentum spectrum of the protons in the target fragmentation region is most sensitive to the definition of the formation time. The inclusive meson and meson resonance spectra are similar in the both versions. 20 refs.; 4 figs.; 1 tab

What can we learn from high-energy hadron-nucleus interactions

International Nuclear Information System (INIS)

Tow, D.M.

1979-12-01

High-energy hadron-nucleus (hA) collisions provide the exciting possibility of giving information about the spacetime development of hadron-hadron interactions and therefore differentiating various multiparticle production models. Some of the major developments in this field during the past decade, both experimentally and theoretically are reviewed. Several general features of the data are pointed out, and several classes of models are discussed. A recently proposed simple spacetime model for high-energy hA collisions is elaborated. Comments are made on the extension to nucleus-nucleus interactions and the future outlook

Triggering on hadronic tau decays: ATLAS meets the challenge

CERN Document Server

Scarcella, M J; The ATLAS collaboration

2011-01-01

Hadronic tau decays play a crucial role in taking Standard Model measurements as well as in the search for physics beyond the Standard Model. However, hadronic tau decays are difficult to identify and trigger on due to their resemblance to QCD jets. Given the large production cross section of QCD processes, designing and operating a trigger system with the capability to efficiently select hadronic tau decays, while maintaining the rate within the bandwidth limits, is a difficult challenge. This contribution will summarize the status and performance of the ATLAS tau trigger system during the 2011 data taking period, emphasizing the key elements of the online selection. Different methods that have been explored to obtain the trigger efficiency curves from data will be shown. Finally, the status of the measurements, which include hadronic tau decays in the final state, will be summarized. In light of the vast statistics collected in 2011, future prospects for triggering on hadronic tau decays in this exciting ne...

Jet Hadronization via Recombination of Parton Showers in Vacuum and in Medium

Energy Technology Data Exchange (ETDEWEB)

Fries, Rainer J.; Han, Kyongchol; Ko, Che Ming

2016-12-15

We introduce a hadronization algorithm for jet parton showers based on a hybrid approach involving recombination of quarks and fragmentation of strings. The algorithm can be applied to parton showers from a shower Monte Carlo generator at the end of their perturbative evolution. The algorithm forces gluon decays and then evaluates the recombination probabilities for quark-antiquark pairs into mesons and (anti)quark triplets into (anti)baryons. We employ a Wigner phase space formulation based on the assumption of harmonic oscillator wave functions for stable hadrons and resonances. Partons too isolated in phase space to find recombination partners are connected by QCD strings to other quarks. Fragmentation of those remnant strings and the decay of all hadron resonances complete the hadronization process. We find that our model applied to parton showers from the PYTHIA Monte Carlo event generator leads to results very similar to pure Lund string fragmentation. We suggest that our algorithm can be readily generalized to jets embedded in quark-gluon plasma by adding sampled thermal partons from the phase transition hypersurface. The recombination of thermal partons and shower partons leads to an enhancement of pions and protons at intermediate momentum at both RHIC and LHC.

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

OpenAIRE

Kuznetsova, Inga; Rafelski, Johann

2008-01-01

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

Charmed hadrons in nuclear medium

NARCIS (Netherlands)

Tolos, L.; Gamermann, D.; Garcia-Recio, C.; Molina, R.; Nieves, J.; Oset, E.; Ramos, A.

We study the properties of charmed hadrons in dense matter within a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner We analyze the behaviour in this dense environment of dynamically-generated baryonic resonances as well as the

Moment analysis of hadronic vacuum polarization

Directory of Open Access Journals (Sweden)

Eduardo de Rafael

2014-09-01

Full Text Available I suggest a new approach to the determination of the hadronic vacuum polarization (HVP contribution to the anomalous magnetic moment of the muon aμHVP in lattice QCD. It is based on properties of the Mellin transform of the hadronic spectral function and their relation to the HVP self-energy in the Euclidean. I show how aμHVP is very well approximated by a few moments associated to this Mellin transform and how these moments can be evaluated in lattice QCD, providing thus a series of tests when compared with the corresponding determinations using experimental data.

Moment analysis of hadronic vacuum polarization

International Nuclear Information System (INIS)

Rafael, Eduardo de

2014-01-01

I suggest a new approach to the determination of the hadronic vacuum polarization (HVP) contribution to the anomalous magnetic moment of the muon a μ HVP in lattice QCD. It is based on properties of the Mellin transform of the hadronic spectral function and their relation to the HVP self-energy in the Euclidean. I show how a μ HVP is very well approximated by a few moments associated to this Mellin transform and how these moments can be evaluated in lattice QCD, providing thus a series of tests when compared with the corresponding determinations using experimental data

Moment analysis of hadronic vacuum polarization

Energy Technology Data Exchange (ETDEWEB)

Rafael, Eduardo de

2014-09-07

I suggest a new approach to the determination of the hadronic vacuum polarization (HVP) contribution to the anomalous magnetic moment of the muon a{sub μ}{sup HVP} in lattice QCD. It is based on properties of the Mellin transform of the hadronic spectral function and their relation to the HVP self-energy in the Euclidean. I show how a{sub μ}{sup HVP} is very well approximated by a few moments associated to this Mellin transform and how these moments can be evaluated in lattice QCD, providing thus a series of tests when compared with the corresponding determinations using experimental data.

Charmed hadron production in pp collision

Science.gov (United States)

Goswami, Umananda Dev

2007-10-01

We investigated the production of charmed hadrons ( D+, D-, D0, D, Λc+, Λ¯c-) in pp collisions as a function of √{s}, xF, p⊥2 and p⊥ in the framework of the QGSJET model. The study of charmed hadron production characteristics in pp collision is particularly important for cosmic ray physics in the context of atmospheric prompt lepton fluxes. Here our aim is to check the reliability of the QGSJET model to be used to study the production of charmed hadrons in cosmic ray hadronic interactions with air nuclei. Charmed hadroproduction cross sections or the charmed hadron average multiplicities in pp collisions are relatively very small. The maximum production of all charmed hadrons takes place with low values of xF, p⊥2, and p⊥ within a small range for all values of √{s} under study. Charmed hadroproduction cross sections as a function of xF and p⊥2 are compared with the LEBC-EHS and LEBC-MPS experiment data for D-meson production. The agreement is quite satisfactory for smaller values of p⊥2 (⩽2 (GeV/c) 2). There is an asymmetry in charmed hadroproduction in pp collision. For all xF, asymmetry is prominent in the low value of √{s}. There is a strong preference for producing Λc+ rather than Λ¯c-baryons, while that for producing D¯ rather than D-mesons for this range of √{s}. Asymmetry increases from zero to ±1 around xF = 0.3 for all values of √{s} and for all charmed hardron groups. The patterns of asymmetric production of different charmed hadrons with xF are approximately the same as that with √{s}. We compare our calculation with the data from Fermilab experiment E781 (SELEX) for Λc-baryon production. The agreement is quite good. The asymmetry of charmed hadroproduction with p⊥ does not follow any well defined pattern.

Correlations in hadron-hadron interactions at high energy

International Nuclear Information System (INIS)

Nguyen Huu Khanh

1978-01-01

Some main features of the experimental results on the correlations in hadron-hadron interactions at high energy are considered. Particular attention is paid to the long-range correlation, short-range correlation and Bose-Einstein effect. Long-range correlations are confirmed by the variation of the number of charged particles produced in the final state depending on energy, violation of Koba-Nielsen- Olesen scaling and the analysis of correlation betWeen the numbers of charged particles emitted in the forward and backward hemispheres. Short-range correlations are discussed from the point of view of ISR pp, 195 GeV/c pN and 32 GeV/c k + p experiments. Bose-Einstein effects are studied up to now only between pions. Pions are not produced directly but from the decay of heavier objects. Some experimental results seem to support the evidence for dynamical long-range correlations. Most of the data are compatible with the independent cluster model

New hadron spectroscopies

International Nuclear Information System (INIS)

Olsen, S.L.

2014-01-01

QCD-motivated models for hadrons predict an assortment of "exotic" hadrons that have structures that are more complex than the quark-antiquark mesons and three-quark baryons of the original quark-parton model. These include pentaquark baryons, the six-quark H-dibaryon, and tetraquark and glueball mesons. Despite extensive experimental searches, no unambiguous candidates for any of these exotic configurations have yet to be identified. On the other hand, a number of meson states, one that seems to be a proton-antiproton bound state, and others that contain either charmed-anticharmed quark pairs or bottom-antibottom quark pairs, have been recently discovered that neither fit into the quark-antiquark meson picture nor match the expected properties of the QCD-inspired exotics. Here I briefly review results from a recent search for the H-dibaryon, and discuss some properties of the newly discovered states –the so-called XYZ mesons– and compare them with expectations for conventional quark-antiquark mesons and the predicted QCD-exotic states. (author)

Hadronic contribution to the muon g-2: A Dyson-Schwinger perspective

Science.gov (United States)

Goecke, T.; Fischer, C. S.; Williams, R.

2012-04-01

We summarize our results for hadronic contributions to the anomalous magnetic moment of the muon (aμ), the one from hadronic vacuum-polarization (HVP) and the light-by-light scattering contribution (LBL), obtained from the Dyson-Schwinger equations (DSEs) of QCD. In the case of HVP we find good agreement with model independent determinations from dispersion relations for aμHV P as well as for the Adler function with deviations well below the ten percent level. From this we conclude that the DSE approach should be capable of describing aμLBL with similar accuracy. We also present results for LBL using a resonance expansion of the quark-anti-quark T-matrix. Our preliminary value is aμLBL=(217±91)×10-11.

Applying the parton model to the fast hadrons at low p(perpendicular)

International Nuclear Information System (INIS)

Teper, M.J.

1978-03-01

The spectra of fast produced hadrons at low p (perpendicular) are discussed within the context of the parton model. Several specific models are critically considered from the experimental and theoretical point of view. Attention is focussed on the quark recombination model and improvements are suggested to overcome its problems; in particular the concept of a chameleon quark is introduced. Contamination of pseudoscalar fragments of the proton by vector meson decay is shown to be small for x > approximately 0.5. Predictions for polarised pp scattering are made. (author)

Properties of hadronic matter near the phase transition

International Nuclear Information System (INIS)

Noronha-Hostler, Jacquelyn

2010-01-01

According to Hagedorn, hadrons should follow an exponential mass spectrum, which the known hadrons follow only up to masses of M∼2 GeV. Beyond this point the mass spectrum is flat, which indicates that there are ''missing'' hadrons, that could potentially contribute significantly to experimental observables. In this thesis I investigate the influence of these ''missing'' Hagedorn states on various experimental signatures of QGP. Strangeness enhancement is considered a signal for QGP because hadronic interactions (even including multi-mesonic reactions) underpredict the hadronic yields (especially for strange particles) at the Relativistic Heavy Ion Collider, RHIC. We show here that the missing Hagedorn states provide extra degrees of freedom that can contribute to fast chemical equilibration times for a hadron gas. We develop a dynamical scheme in which possible Hagedorn states contribute to fast chemical equilibration times of X anti X pairs (where X=p, K, Λ, or Ω) inside a hadron gas and just below the critical temperature. Within this scheme, we use master equations and derive various analytical estimates for the chemical equilibration times. Applying a Bjorken picture to the expanding fireball, the hadrons can, indeed, quickly chemically equilibrate for both an initial overpopulation or underpopulation of Hagedorn resonances. Our hadron resonance gas model, including the additional Hagedorn states, is used to obtain an upper bound on the shear viscosity to entropy density ratio, η/s, of hadronic matter near T c that is close to 1/(4/π). We show how the measured particle ratios can be used to provide non-trivial information about T c of the QCD phase transition. This is obtained by including the effects of highly massive Hagedorn resonances on statistical models, which are generally used to describe hadronic yields. The inclusion of the ''missing'' Hagedorn states creates a dependence of the thermal fits on the Hagedorn temperature, T H , and leads to a

Measurement of $\\Delta^{++}$(1232) production in hadronic Z decays

CERN Document Server

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

1995-01-01

A measurement of the \\Delta^{++}(1232) inclusive production in hadronic decays of the Z at LEP is presented, based on 1.3 million hadronic events collected~ by the DELPHI~ detector in the 1994 LEP running~ period. The DELPHI ring imaging Cherenkov counters are used for identifying hadrons. The average \\Delta^{++}(1232) multiplicity per hadronic event is 0.079 \\pm 0.015 which is more than a factor of two below the JETSET, HERWIG and UCLA model predictions. It agrees with a recently proposed universal mass dependence of particle production rates in e^{+}e^- annihilations.

PREFACE: Focus section on Hadronic Physics Focus section on Hadronic Physics

Science.gov (United States)

Roberts, Craig; Swanson, Eric

2007-07-01

Hadronic physics is the study of strongly interacting matter and its underlying theory, Quantum Chromodynamics (QCD). The field had its beginnings after World War Two, when hadrons were discovered in ever increasing numbers. Today, it encompasses topics like the quark-gluon structure of hadrons at varying scales, the quark-gluon plasma and hadronic matter at extreme temperature and density; it also underpins nuclear physics and has significant impact on particle physics, astrophysics, and cosmology. Among the goals of hadronic physics are to determine the parameters of QCD, understand the origin and characteristics of confinement, understand the dynamics and consequences of dynamical chiral symmetry breaking, explore the role of quarks and gluons in nuclei and in matter under extreme conditions and understand the quark and gluon structure of hadrons. In general, the process is one of discerning the relevant degrees of freedom and relating these to the fundamental fields of QCD. The emphasis is on understanding QCD, rather than testing it. The papers gathered in this special focus section of Journal of Physics G: Nuclear and Particle Physics attempt to cover this broad range of subjects. Alkofer and Greensite examine the issue of quark and gluon confinement with the focus on models of the QCD vacuum, lattice gauge theory investigations, and the relationship to the AdS/CFT correspondence postulate. Arrington et al. review nucleon form factors and their role in determining quark orbital momentum, the strangeness content of the nucleon, meson cloud effects, and the transition from nonperturbative to perturbative QCD dynamics. The physics associated with hadronic matter at high temperature and density and at low Bjorken-x at the Relativistic Heavy Ion Collider (RHIC), the SPS at CERN, and at the future LHC is summarized by d'Enterria. The article of Lee and Smith examines experiment and theory associated with electromagnetic meson production from nucleons and

Hyperasymptotics and quark-hadron duality violations in QCD

Science.gov (United States)

Boito, Diogo; Caprini, Irinel; Golterman, Maarten; Maltman, Kim; Peris, Santiago

2018-03-01

We investigate the origin of the quark-hadron duality-violating terms in the expansion of the QCD two-point vector correlation function at large energies in the complex q2 plane. Starting from the dispersive representation for the associated polarization, the analytic continuation of the operator product expansion from the Euclidean to the Minkowski region is performed by means of a generalized Borel-Laplace transform, borrowing techniques from hyperasymptotics. We establish a connection between singularities in the Borel plane and quark-hadron duality-violating contributions. Starting with the assumption that for QCD at Nc=∞ the spectrum approaches a Regge trajectory at large energy, we obtain an expression for quark-hadron duality violations at large, but finite Nc.

On the model dependence of the determination of the strong coupling constant in second order QCD from e+e--annihilation into hadrons

International Nuclear Information System (INIS)

Achterberg, O.; D'Agostini, G.; Apel, W.D.; Engler, J.; Fluegge, G.; Forstbauer, B.; Fries, D.C.; Fues, W.; Gamerdinger, K.; Henkes, T.; Hopp, G.; Krueger, M.; Kuester, H.; Mueller, H.; Randoll, H.; Schmidt, G.; Schneider, H.; Boer, W. de; Buschhorn, G.; Grindhammer, G.; Grosse-Wiesmann, P.; Gunderson, B.; Kiesling, C.; Kotthaus, R.; Kruse, U.; Lierl, H.; Lueers, D.; Oberlack, H.; Schacht, P.; Bonneaud, G.; Colas, P.; Cordier, A.; Davier, M.; Fournier, D.; Grivaz, J.F.; Haissinski, J.; Journe, V.; Laplanche, F.; Le Diberder, F.; Mallik, U.; Ros, E.; Veillet, J.J.; Behrend, H.J.; Fenner, H.; Schachter, M.J.; Schroeder, V.; Sindt, H.

1983-12-01

Hadronic events obtained with the CELLO detector at PETRA are compared with second order QCD predictions using different models for the fragmentation of quarks and gluons into hadrons. We find that the model dependence in the determination of the strong coupling constant persists when going from first to second order QCD calculations. (orig.)

Investigation of tt in the full hadronic final state at CDF with a neural network approach

CERN Document Server

Sidoti, A; Busetto, G; Castro, A; Dusini, S; Lazzizzera, I; Wyss, J

2001-01-01

In this work we present the results of a neural network (NN) approach to the measurement of the tt production cross-section and top mass in the all-hadronic channel, analyzing data collected at the Collider Detector at Fermilab (CDF) experiment. We have used a hardware implementation of a feedforward neural network, TOTEM, the product of a collaboration of INFN (Istituto Nazionale Fisica Nucleare)-IRST (Istituto per la Ricerca Scientifica e Tecnologica)-University of Trento, Italy. Particular attention has been paid to the evaluation of the systematics specifically related to the NN approach. The results are consistent with those obtained at CDF by conventional data selection techniques. (38 refs).

Strange baryon production in Z hadronic decays

CERN Document Server

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

1995-01-01

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

Physics at Hadronic Colliders (4/4)

CERN Multimedia

CERN. Geneva

2008-01-01

Hadron colliders are often called "discovery machines" since they produce the highest mass particles and thus give often the best chance to discover new high mass particles. Currently they are particularly topical since the Large Hadron Collider will start operating later this year, increasing the centre-of-mass energy by a factor of seven compared to the current highest energy collider, the Tevatron. I will review the benefits and challenges of hadron colliders and review some of the current physics results from the Tevatron and give an outlook to the future results we are hoping for at the LHC. Prerequisite knowledge: Introduction to Particle Physics (F. Close), Detectors (W. Riegler, at least mostly) and The Standard Model (A. Pich)

Physics at Hadronic Colliders (1/4)

CERN Multimedia

CERN. Geneva

2008-01-01

Hadron colliders are often called "discovery machines" since they produce the highest mass particles and thus give often the best chance to discover new high mass particles. Currently they are particularly topical since the Large Hadron Collider will start operating later this year, increasing the centre-of-mass energy by a factor of seven compared to the current highest energy collider, the Tevatron. I will review the benefits and challenges of hadron colliders and review some of the current physics results from the Tevatron and give an outlook to the future results we are hoping for at the LHC. Prerequisite knowledge: Introduction to Particle Physics (F. Close), Detectors (W. Riegler, at least mostly) and The Standard Model (A. Pich)

Physics at Hadronic Colliders (2/4)

CERN Multimedia

CERN. Geneva

2008-01-01

Hadron colliders are often called "discovery machines" since they produce the highest mass particles and thus give often the best chance to discover new high mass particles. Currently they are particularly topical since the Large Hadron Collider will start operating later this year, increasing the centre-of-mass energy by a factor of seven compared to the current highest energy collider, the Tevatron. I will review the benefits and challenges of hadron colliders and review some of the current physics results from the Tevatron and give an outlook to the future results we are hoping for at the LHC. Prerequisite knowledge: Introduction to Particle Physics (F. Close), Detectors (W. Riegler, at least mostly) and The Standard Model (A. Pich)

Physics at Hadronic Colliders (3/4)

CERN Multimedia

CERN. Geneva

2008-01-01

Hadron colliders are often called "discovery machines" since they produce the highest mass particles and thus give often the best chance to discover new high mass particles. Currently they are particularly topical since the Large Hadron Collider will start operating later this year, increasing the centre-of-mass energy by a factor of seven compared to the current highest energy collider, the Tevatron. I will review the benefits and challenges of hadron colliders and review some of the current physics results from the Tevatron and give an outlook to the future results we are hoping for at the LHC. Prerequisite knowledge: Introduction to Particle Physics (F. Close), Detectors (W. Riegler, at least mostly) and The Standard Model (A. Pich)

Nuclear matter descriptions including quark structure of the hadrons

International Nuclear Information System (INIS)

Huguet, R.

2008-07-01

It is nowadays well established that nucleons are composite objects made of quarks and gluons, whose interactions are described by Quantum chromodynamics (QCD). However, because of the non-perturbative character of QCD at the energies of nuclear physics, a description of atomic nuclei starting from quarks and gluons is still not available. A possible alternative is to construct effective field theories based on hadronic degrees of freedom, in which the interaction is constrained by QCD. In this framework, we have constructed descriptions of infinite nuclear matter in relativistic mean field theories taking into account the quark structure of hadrons. In a first approach, the in medium modifications of mesons properties is dynamically obtained in a Nambu-Jona-Lasinio (NJL) quark model. This modification is taken into account in a relativistic mean field theory based on a meson exchange interaction between nucleons. The in-medium modification of mesons masses and the properties of infinite nuclear matter have been studied. In a second approach, the long and short range contributions to the in-medium modification of the nucleon are determined. The short range part is obtained in a NJL quark model of the nucleon. The long range part, related to pions exchanges between nucleons, has been determined in the framework of Chiral Perturbation theory. These modifications have been used to constrain the couplings of a point coupling relativistic mean field model. A realistic description of the saturation properties of nuclear matter is obtained. (author)

Intermediate and high energy nuclear reactions at the hadronic structural level

Energy Technology Data Exchange (ETDEWEB)

Slowinski, B [Institute of Physics, Warsaw, University of Technology, Poland, Institute of Atomic Energy, Swierk, (Poland)

1997-12-31

Form tens of MeV to several hundred of GeV is stretched out quite a large interval of energy when the interaction between hadrons (for instance, pion/nucleon-nucleus and nucleus-nucleus reactions) can be described by the considerably simplified way with still acceptable accuracy. This happens because in this energy region hadrons (i.e. pions, nucleons etc.) remain quasiparticles of nuclear matter mostly without revealing any internal structure, their de Broglie`s wavelength is much shorter as compared to the average intranuclear nucleon`s distance, and the energy transfers in the reaction are, on the average, significantly greater than the binding energy of nucleons inside nuclei. Consequently an approach to the analysis of these phenomena based on simple geometric and probabilistic considerations is justifiable, especially for many practical purposes, in particular, for shielding and dosimetric estimations, material behaviour prediction, as well as for the approximate evaluation of electronuclear breeding effects in different composites of target materials, for nuclear passivation problems and so on. In this work basic physical reasons of such a simplified picture of intermediate and high energy nuclear reactions are presented. The most usual phenomenological models of hadronic multiple emission/production and recent results of the cascade evaporation type models, are also discussed. 2 figs.

Sum rules for quasifree scattering of hadrons

Science.gov (United States)

Peterson, R. J.

2018-02-01

The areas d σ /d Ω of fitted quasifree scattering peaks from bound nucleons for continuum hadron-nucleus spectra measuring d2σ /d Ω d ω are converted to sum rules akin to the Coulomb sums familiar from continuum electron scattering spectra from nuclear charge. Hadronic spectra with or without charge exchange of the beam are considered. These sums are compared to the simple expectations of a nonrelativistic Fermi gas, including a Pauli blocking factor. For scattering without charge exchange, the hadronic sums are below this expectation, as also observed with Coulomb sums. For charge exchange spectra, the sums are near or above the simple expectation, with larger uncertainties. The strong role of hadron-nucleon in-medium total cross sections is noted from use of the Glauber model.

On Some Novel Ideas in Hadron Physics. Part II

Directory of Open Access Journals (Sweden)

Christianto V.

2010-04-01

Full Text Available As a continuation of the preceding section, we shortly review a series of novel ideas on the physics of hadrons. In the present paper, emphasis is given on some different approaches to the hadron physics, which may be called as “programs” in the sense of Lakatos. For clarity, we only discuss geometrization program, symmetries / unification program, and phenomenology of inter-quark potential program.

On Some Novel Ideas in Hadron Physics. Part II

Directory of Open Access Journals (Sweden)

Smarandache F.

2010-04-01

Full Text Available As a continuation of the preceding section, we shortly review a series of novel ideas on the physics of hadrons. In the present paper, emphasis is given on some different approaches to the hadron physics, which may be called as "programs" in the sense of Lakatos. For clarity, we only discuss geometrization program, symmetries/unification program, and phenomenology of inter-quark potential program.

Hadronic interactions in the MINOS detectors

Energy Technology Data Exchange (ETDEWEB)

Kordosky, Michael Alan [Univ. of Texas, Austin, TX (United States)

2004-08-01

MINOS, the Main Injector Neutrino Oscillation Search, will study neutrino flavor transformations using a Near detector at the Fermi National Accelerator Laboratory and a Far detector located in the Soudan Underground Laboratory in northern Minnesota. The MINOS collaboration also constructed the CalDet (calibration detector), a smaller version of the Near and Far detectors, to determine the topological and signal response to hadrons, electrons and muons. The detector was exposed to test-beams in the CERN Proton Synchrotron East Hall during 2001-2003, where it collected events at momentum settings between 200 MeV/c and 10 GeV/c. In this dissertation we present results of the CalDet experiment, focusing on the topological and signal response to hadrons. We briefly describe the MINOS experiment and its iron-scintillator tracking-sampling calorimters as a motivation for the CalDet experiment. We discuss the operation of the CalDet in the beamlines as well as the trigger and particle identification systems used to isolate the hadron sample. The method used to calibrate the MINOS detector is described and validated with test-beam data. The test-beams were simulated to model the muon flux, energy loss upstream of the detector and the kaon background. We describe the procedure used to discriminate between pions and muons on the basis of the event topology. The hadron samples were used to benchmark the existing GEANT3 based hadronic shower codes and determine the detector response and resolution for pions and protons. We conclude with comments on the response to single hadrons and to neutrino induced hadronic showers.

Born term for high-energy meson-hadron collisions from QCD and chiral quark model

International Nuclear Information System (INIS)

Ochs, W.; Shimada, T.

1988-01-01

Various experimental observations reveal a sizeable hard component in the high-energy 'soft' hadronic collisions. For primary meson beams we propose a QCD Born term which describes the dissociation of the primary meson into a quark-antiquark pair in the gluon field of the target. A pointlike effective pion-quark coupling is assumed as in the chiral quark model by Manohar and Georgi. We derive the total cross sections which for pion beams, for example, are given in terms of f π -2 and some properties of the hadronic final states. In particular, we stress the importance of studying three-jet events in meson-nucleon scattering and discuss the seagull effect. (orig.)

Testing the hadronic spectrum in the strange sector

International Nuclear Information System (INIS)

Parotto, P.

2017-01-01

Heavier resonances are continually being added to the hadronic spectrum from the Particle Data Group that follow an exponentially increasing mass spectrum. However, it has been suggested that even further states predicted from Quark Models are needed in the hadronic spectrum in order to improve the agreement between the hadron resonance gas model predictions and lattice QCD data. We find that the inclusion of such states with extrapolated branching ratios slightly decreases the freezeout temperature. To eliminate ambiguities, we introduce a first principle method to extract the freeze-out temperature for charged kaons from experimental data, which yields a lower bound of T fo ≳ 145 MeV for the highest collision energy at RHIC. (paper)

Hadron chemistry in heavy ion collisions

International Nuclear Information System (INIS)

Montvay, I.; Zimanyi, J.

1978-06-01

In the models for energetic heavy ion reactions it is assumed that during the reaction a hot and dense nuclear matter, a fireball is formed from all or a part of nucleons of the target and projectile nuclei. The process is similar to the chemical processes leading to dynamical equilibrium. The relaxation times necessary to establish ''chemical'' equilibrium among different hadrons in hot, dense hadronic matter is deducted in a statistical model. Consequences for heavy ion collisions are discussed. The possibility of Bose-Einstein pion condensation around the break-up time of the nuclear fireball is pointed out. (D.P.)

The hadron to quark/gluon transition

International Nuclear Information System (INIS)

Brown, G.E.; Bethe, H.A.; Pizzochero, P.M.

1991-01-01

In this paper we are concerned with the hadron to quark/gluon transition. We describe the equilibrium states of hadronic matter by a Hagedorn spectrum; introducing scaling masses, as dictated by the restoration of chiral invariance with increasing temperature, we show that in the chiral SU(2) f limit there is a maximum hadron temperature (T H ) max ≅ 128 MeV. Since the quark/gluon perturbative phase involves restoration of conformal invariance, we take the bag constant to be the conformal anomaly, i.e. the gluon condensate. The stability condition P QG > 0 for the pressure requires that there is a minimum temperature; we find (T QG ) min ≅ 172 MeV for SU(2) f . According to the simple Hagedorn model, there appears to be a region of temperature between (T H ) max and (T QG ) min in which no admissible equilibrium states exist. Since the two phases cannot exist at a common temperature, in this model there is no QCD phase transition. (orig.)

Spatially improved operators for excited hadrons on the lattice

International Nuclear Information System (INIS)

Burch, Tommy; Gattringer, Christof; Schaefer, Andreas; Glozman, Leonid Ya.; Kleindl, Reinhard; Lang, C.B.

2004-01-01

We present a new approach for determining spatially optimized operators that can be used for lattice spectroscopy of excited hadrons. Jacobi smeared quark sources with different widths are combined to construct hadron operators with different spatial wave functions. We use the variational method to determine those linear combinations of operators that have optimal overlap with ground and excited states. The details of the new approach are discussed and we demonstrate the power of the method using examples from quenched baryon and meson spectroscopy. In particular, we study the Roper state and ρ(1450) and discuss some physical implications of our tests

Supersymmetry at hadron supercolliders

International Nuclear Information System (INIS)

Dzialo, D.L.

1989-01-01

At the next generation of hadron supercolliders, the proposed US Superconducting Supercollider (SSC) and the European Large Hadron Collider (LHC), protons will be collided at such high energy to allow the creation of new particles with masses greater those that have been previously created in the laboratory. One of the most important questions to be resolved at these accelerators is whether or not any supersymmetric extension of the Standard Model is manifest below the TeV scale. It is expected that the strongly-interacting supersymmetric particles, the gluinos and squarks, will be pair-produced in the most abundance there. Light gluinos primarily decay into quarks and the lightest supersymmetric particle, which is assumed to escape detection; this gives the classic supersymmetric signature of events with large missing momentum. It is known, however, that for gluinos of masses larger than just 100 GeV this process is no longer the preferred gluino decay channel. New signals must therefore be sought to either detect these particles, or to set meaningful lower mass limits. It is in this work that such new detection strategies for supersymmetry at hadron supercolliders are proposed. Gluino and squark production rates and decay channels are studied in a model-independent fashion over the entire theoretical mass range of interest. New experimental signatures are proposed and compared with sources of background over a wide region of the parameter space that characterizes different supersymmetric models

Particle production at energies available at the CERN Large Hadron Collider within an evolutionary model

Science.gov (United States)

Sinyukov, Yu. M.; Shapoval, V. M.

2018-06-01

The particle yields and particle number ratios in Pb+Pb collisions at the CERN Large Hadron Collider (LHC) energy √{sN N}=2.76 TeV are described within the integrated hydrokinetic model (iHKM) at two different equations of state (EoS) for quark-gluon matter and the two corresponding hadronization temperatures T =165 MeV and T =156 MeV. The role of particle interactions at the final afterburner stage of the collision in the particle production is investigated by means of comparison of the results of full iHKM simulations with those where the annihilation and other inelastic processes (except for resonance decays) are switched off after hadronization/particlization, similarly as in the thermal models. An analysis supports the picture of continuous chemical freeze-out in the sense that the corrections to the sudden chemical freeze-out results, which arise because of the inelastic reactions at the subsequent evolution times, are noticeable and improve the description of particle number ratios. An important observation is that, although the particle number ratios with switched-off inelastic reactions are quite different at different particlization temperatures which are adopted for different equations of state to reproduce experimental data, the complete iHKM calculations bring very close results in both cases.

Study of the Weak Charged Hadronic Current in b Decays

CERN Document Server

Acciarri, M; Aguilar-Benítez, M; Ahlen, S P; Alpat, B; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alverson, G; Alviggi, M G; Ambrosi, G; Anderhub, H; Andreev, V P; Angelescu, T; Anselmo, F; Antreasyan, D; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Baksay, L; Ball, R C; Banerjee, S; Banicz, K; Barillère, R; Barone, L; Bartalini, P; Baschirotto, A; Basile, M; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Bhattacharya, S; Biasini, M; Biland, A; Bilei, G M; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böck, R K; Böhm, A; Borgia, B; Boucham, A; Bourilkov, D; Bourquin, Maurice; Boutigny, D; Branson, J G; Brigljevic, V; Brock, I C; Buffini, A; Buijs, A; Burger, J D; Burger, W J; Busenitz, J K; Buytenhuijs, A O; Cai, X D; Campanelli, M; Capell, M; Cara Romeo, G; Caria, M; Carlino, G; Cartacci, A M; Casaus, J; Castellini, G; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada-Canales, M; Cesaroni, F; Chamizo-Llatas, M; Chan, A; Chang, Y H; Chaturvedi, U K; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chen, M; Chiefari, G; Chien, C Y; Choi, M T; Cifarelli, Luisa; Cindolo, F; Civinini, C; Clare, I; Clare, R; Cohn, H O; Coignet, G; Colijn, A P; Colino, N; Commichau, V; Costantini, S; Cotorobai, F; de la Cruz, B; Csilling, Akos; Dai, T S; D'Alessandro, R; De Asmundis, R; De Boeck, H; Degré, A; Deiters, K; Denes, P; De Notaristefani, F; DiBitonto, Daryl; Diemoz, M; Van Dierendonck, D N; Di Lodovico, F; Dionisi, C; Dittmar, Michael; Dominguez, A; Doria, A; Dorne, I; Dova, M T; Drago, E; Duchesneau, D; Duinker, P; Durán, I; Dutta, S; Easo, S; Efremenko, Yu V; El-Mamouni, H; Engler, A; Eppling, F J; Erné, F C; Ernenwein, J P; Extermann, Pierre; Fabre, M; Faccini, R; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, Marta; Fenyi, B; Ferguson, T; Fernández, D; Ferroni, F; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Forconi, G; Fredj, L; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gau, S S; Gentile, S; Gerald, J; Gheordanescu, N; Giagu, S; Goldfarb, S; Goldstein, J; Gong, Z F; Gougas, Andreas; Gratta, Giorgio; Grünewald, M W; Gupta, V K; Gurtu, A; Gutay, L J; Hartmann, B; Hasan, A; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Van Hoek, W C; Hofer, H; Hoorani, H; Hou, S R; Hu, G; Innocente, Vincenzo; Janssen, H; Jenkes, K; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kasser, A; Khan, R A; Kamrad, D; Kamyshkov, Yu A; Kapustinsky, J S; Karyotakis, Yu; Kaur, M; Kienzle-Focacci, M N; Kim, D; Kim, J K; Kim, S C; Kim, Y G; Kinnison, W W; Kirkby, A; Kirkby, D; Kirkby, Jasper; Kiss, D; Kittel, E W; Klimentov, A; König, A C; Korolko, I; Koutsenko, V F; Krämer, R W; Krenz, W; Kuijten, H; Kunin, A; Ladrón de Guevara, P; Landi, G; Lapoint, C; Lassila-Perini, K M; Laurikainen, P; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Lee Jae Sik; Lee, K Y; Leggett, C; Le Goff, J M; Leiste, R; Leonardi, E; Levchenko, P M; Li Chuan; Lieb, E H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lu, W; Lü, Y S; Lübelsmeyer, K; Luci, C; Luckey, D; Luminari, L; Lustermann, W; Ma Wen Gan; Maity, M; Majumder, G; Malgeri, L; Malinin, A; Maña, C; Mangla, S; Marchesini, P A; Marin, A; Martin, J P; Marzano, F; Massaro, G G G; McNally, D; Mele, S; Merola, L; Meschini, M; Metzger, W J; Von der Mey, M; Mi, Y; Mihul, A; Van Mil, A J W; Mirabelli, G; Mnich, J; Molnár, P; Monteleoni, B; Moore, R; Morganti, S; Moulik, T; Mount, R; Müller, S; Muheim, F; Nagy, E; Nahn, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Nippe, A; Nisati, A; Nowak, H; Opitz, H; Organtini, G; Ostonen, R; Pandoulas, D; Paoletti, S; Paolucci, P; Park, H K; Pascale, G; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Peach, D; Pei, Y J; Pensotti, S; Perret-Gallix, D; Petrak, S; Pevsner, A; Piccolo, D; Pieri, M; Pinto, J C; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Postema, H; Produit, N; Prokofev, D; Prokofiev, D O; Rahal-Callot, G; Rancoita, P G; Rattaggi, M; Raven, G; Razis, P A; Read, K; Ren, D; Rescigno, M; Reucroft, S; Van Rhee, T; Riemann, S; Riemers, B C; Riles, K; Rind, O; Ro, S; Robohm, A; Rodin, J; Rodríguez-Calonge, F J; Roe, B P; Romero, L; Rosier-Lees, S; Rosselet, P; Van Rossum, W; Roth, S; Rubio, Juan Antonio; Rykaczewski, H; Salicio, J; Sánchez, E; Santocchia, A; Sarakinos, M E; Sarkar, S; Sassowsky, M; Sauvage, G; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Schmitz, P; Schneegans, M; Scholz, N; Schopper, Herwig Franz; Schotanus, D J; Schwenke, J; Schwering, G; Sciacca, C; Sciarrino, D; Sens, Johannes C; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shukla, J; Shumilov, E; Shvorob, A V; Siedenburg, T; Son, D; Sopczak, André; Soulimov, V; Smith, B; Spillantini, P; Steuer, M; Stickland, D P; Stone, H; Stoyanov, B; Strässner, A; Strauch, K; Sudhakar, K; Sultanov, G G; Sun, L Z; Susinno, G F; Suter, H; Swain, J D; Tang, X W; Tauscher, Ludwig; Taylor, L; Ting, Samuel C C; Ting, S M; Tonutti, M; Tonwar, S C; Tóth, J; Tully, C; Tuchscherer, H; Tung, K L; Uchida, Y; Ulbricht, J; Uwer, U; Valente, E; Van de Walle, R T; Vesztergombi, G; Vetlitskii, I; Viertel, Gert M; Vivargent, M; Völkert, R; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Vorvolakos, A; Wadhwa, M; Wallraff, W; Wang, J C; Wang, X L; Wang, Z M; Weber, A; Wittgenstein, F; Wu, S X; Wynhoff, S; Xu, J; Xu, Z Z; Yang, B Z; Yang, C G; Yao, X Y; Ye, J B; Yeh, S C; You, J M; Zalite, A; Zalite, Yu; Zemp, P; Zeng, Y; Zhang, Z; Zhang, Z P; Zhou, B; Zhou, Y; Zhu, G Y; Zhu, R Y; Zichichi, Antonino; Ziegler, F

1997-01-01

Charged and neutral particle multiplicities of jets associated with identified semileptonic and hadronic b decays are studied. The observed differences between these jets are used to determine the inclusive properties of the weak charged hadronic current. The average charged particle multiplicity of the weak charged hadronic current in b decays is measured for the first time to be 2.69$\\pm$0.07(stat.)$\\pm$0.14(syst.). This result is in good agreement with the JETSET hadronization model of the weak charged hadronic current if 40$\\pm$17\\% of the produced mesons are light--flavored tensor (L=1) mesons. This level of tensor meson production is consistent with the measurement of the $\\pi^0$ multiplicity in the weak charged hadronic current in b decays. \\end{abstract}

Hadron muoproduction at the COMPASS experiment

International Nuclear Information System (INIS)

Rajotte, Jean-Francois

2010-01-01

are presented for different kinematical intervals. These multiplicities can be used as benchmarks to verify the reliability of theoretical models. The subject of parton intrinsic transverse momentum is of growing interest to the spin structure community. The picture of partons moving collinear with the proton momentum is not sufficient to explain many spin features of the nucleons. Since a few years, transverse momentum dependent (TMD) distributions are integrated into theoretical models of nucleon interactions. Assumptions are made and it is to the experiment to test them. The Gaussian ansatz which assumes Gaussian behavior of the TMD distribution functions is applied and investigated. This model is very popular for its simplicity and ability to reproduce many experimental results. This analysis contributes to the verification of this model and suggests possible ameliorations. Based on this model, the intrinsic transverse momentum of the partons within the nucleon is extracted from the average transverse momenta of the measured hadrons. The extraction is carried out for different kinematical intervals to verify basic assumptions of the nucleon structure and fragmentation of partons into hadrons. Some insights are acquired about the flavor and kinematical dependence of the partons intrinsic transverse momenta. Finally, further studies and related analyses are proposed. (orig.)

Hadron muoproduction at the COMPASS experiment

Energy Technology Data Exchange (ETDEWEB)

Rajotte, Jean-Francois

2010-09-30

are presented for different kinematical intervals. These multiplicities can be used as benchmarks to verify the reliability of theoretical models. The subject of parton intrinsic transverse momentum is of growing interest to the spin structure community. The picture of partons moving collinear with the proton momentum is not sufficient to explain many spin features of the nucleons. Since a few years, transverse momentum dependent (TMD) distributions are integrated into theoretical models of nucleon interactions. Assumptions are made and it is to the experiment to test them. The Gaussian ansatz which assumes Gaussian behavior of the TMD distribution functions is applied and investigated. This model is very popular for its simplicity and ability to reproduce many experimental results. This analysis contributes to the verification of this model and suggests possible ameliorations. Based on this model, the intrinsic transverse momentum of the partons within the nucleon is extracted from the average transverse momenta of the measured hadrons. The extraction is carried out for different kinematical intervals to verify basic assumptions of the nucleon structure and fragmentation of partons into hadrons. Some insights are acquired about the flavor and kinematical dependence of the partons intrinsic transverse momenta. Finally, further studies and related analyses are proposed. (orig.)

Hadronization of quark-diquark model for nucleon structure and nuclear force by path integral

International Nuclear Information System (INIS)

Nagata, Keitaro

2003-01-01

One of the central issues of the hadron physics is how to interpret the properties and the origin of nuclear force. Nuclear force is in principle the manifestation of dynamics of quarks and gluons but no trial has been successful yet in describing the nuclear force by using QCD, the fundamental theory of the strong interactions. Phenomenon related to the chiral symmetry and the spontaneous breaking of the chiral symmetry is one of the important phenomena for the understanding of hadron physics. Nambu-Jona-Lasinio (NJL) model is one of the quark system models to explain the phenomena concerning the chiral symmetry. Although the method to deduce the Lagrangian describing mesons by applying the path integral to NJL model has been well known as the bosonization, it has been difficult to extend it to baryons because baryons are three-body system. In this paper, a method is reported to deduce Lagrangian which describes baryon-meson from quark-diquark Lagrangian by assuming that baryons are the bound states of quark and diquark. (S. Funahashi)

Confinement and quark structure of light hadrons

International Nuclear Information System (INIS)

Efimov, G.V.; Ivanov, M.A.

1988-01-01

We present a quark confinement model (QCM) for the description of the low-energy physics of light hadrons (mesons and baryons). The model is based on two hypotheses. First, the quark confinement is realized as averaging over vacuum gluon fields which are believed to provide the confinement of any colour objects. Second, hadrons are treated as collective colourless excitations of quark-gluon interactions. The description of strong, electromagnetic and weak interactions of mesons and baryons at the low energy is given from a unique point of view

Quantum groups in hadron phenomenology

International Nuclear Information System (INIS)

Gavrilik, A.M.

1997-01-01

We show that application of quantum unitary groups, in place of ordinary flavor SU(n f ), to such static aspects of hadron phenomenology as hadron masses and mass formulas is indeed fruitful. So-called q-deformed mass formulas are given for octet baryons 1/2 + and decuplet baryons 3/2 + , as well as for the case of vector mesons 1 - involving heavy flavors. For deformation parameter q, rigid fixation of values is used. New mass sum rules of remarkable accuracy are presented. As shown in decuplet case, the approach accounts for effects highly nonlinear in SU(3)-breaking. Topological implication (possible connection with knots) for singlet vector mesons and the relation q ↔ Θ c (Cabibbo angle) in case of baryons are considered

Hadron therapy information sharing prototype

CERN Document Server

Roman, Faustin Laurentiu; Kanellopoulos, Vassiliki; Amoros, Gabriel; Davies, Jim; Dosanjh, Manjit; Jena, Raj; Kirkby, Norman; Peach, Ken; Salt, Jose

2013-01-01

The European PARTNER project developed a prototypical system for sharing hadron therapy data. This system allows doctors and patients to record and report treatment-related events during and after hadron therapy. It presents doctors and statisticians with an integrated view of adverse events across institutions, using open-source components for data federation, semantics, and analysis. There is a particular emphasis upon semantic consistency, achieved through intelligent, annotated form designs. The system as presented is ready for use in a clinical setting, and amenable to further customization. The essential contribution of the work reported here lies in the novel data integration and reporting methods, as well as the approach to software sustainability achieved through the use of community-supported open-source components.

Time evolution of hadronization and grey tracks in DIS off nuclei

International Nuclear Information System (INIS)

Ciofi degli Atti, C.; Kopeliovich, B.Z.

2005-01-01

The analysis of the grey tracks produced in deep inelastic scattering (DIS) off nuclei provides important information on the space-time development of hadronization in nuclear medium. This method is complementary to the measurement of nuclear attenuation of leading inclusive hadrons. While the latter is focused on the hadronization dynamics for the quite rare process of leading hadrons production, the former covers the main bulk of inelastic events, and its Q 2 dependence is a very sensitive tool to discriminate between different models of hadronization. Employing the model of perturbative hadronization developed earlier, we calculate the Q 2 and x Bj dependences of the number of collisions and relate it to the mean number of grey tracks, using an empirical relation obtained from the analysis of data from the Fermilab E665 experiment on DIS of muons off the Xe nucleus. We found the number of grey tracks to rise steeply with Q 2 in good agreement with the experimental data

Hadron-nucleus collisions

International Nuclear Information System (INIS)

Strugalski, Z.

1981-01-01

Qualitative picture of high energy hadron-nucleus collision process, emerging from the analysis of experimental data, is presented. Appropriate description procedure giving a possibility of reproducing various characteristics of this process in terms of the data on elementary hadron-nucleon interaction is proposed. Formula reproducing hadron-nucleus collision cross sections is derived. Inelastic collision cross sections for pion-nucleus and proton-nucleus reactions at wide energy interval are calculated for Pb, Ag, and Al targets. A-dependence of cross sections for pion-nucleus and proton-nucleus collisions at nearly 50 GeV/c momentum were calculated and compared with existing experimental data. Energy dependence of cross sections for hadron-nucleus collisions is determined simply by energy dependence of corresponding cross sections for hadron-nucleon collisions; A-dependence is determined simply by nuclear sizes and nucleon density distributions in nuclei

Flat beams in a 50 TeV hadron collider

International Nuclear Information System (INIS)

Peggs, S.; Harrison, M.; Pilat, F.; Syphers, M.

1997-01-01

The basic beam dynamics of a next generation 50 x 50 TeV hadron collider based on a high field magnet approach have been outlined over the past several years. Radiation damping not only produces small emittances, but also flat beams, just as in electron machines. Based on open-quotes Snowmass 96close quotes parameters, we investigate the issues associated with flat beams in very high energy hadron colliders

Quadrupole moments of hadrons

International Nuclear Information System (INIS)

Krivoruchenko, M.I.

1985-01-01

In chiral bag model an expression is obtained for the quark wave functions with account of color and pion interaction of quarks. The quadrupole moments of nonstrange hadrons are calculated. Quadrupole moment of nucleon isobar is found to be Q(Δ)=-6.3x10 -28 esub(Δ)(cm)sup(2). Fredictions of the chiral bag model are in strong disagreement with the non-relativistic quark model

Properties of hadronic matter near the phase transition

Energy Technology Data Exchange (ETDEWEB)

Noronha-Hostler, Jacquelyn

2010-12-08

According to Hagedorn, hadrons should follow an exponential mass spectrum, which the known hadrons follow only up to masses of M{approx}2 GeV. Beyond this point the mass spectrum is flat, which indicates that there are ''missing'' hadrons, that could potentially contribute significantly to experimental observables. In this thesis I investigate the influence of these ''missing'' Hagedorn states on various experimental signatures of QGP. Strangeness enhancement is considered a signal for QGP because hadronic interactions (even including multi-mesonic reactions) underpredict the hadronic yields (especially for strange particles) at the Relativistic Heavy Ion Collider, RHIC. We show here that the missing Hagedorn states provide extra degrees of freedom that can contribute to fast chemical equilibration times for a hadron gas. We develop a dynamical scheme in which possible Hagedorn states contribute to fast chemical equilibration times of X anti X pairs (where X=p, K, {lambda}, or {omega}) inside a hadron gas and just below the critical temperature. Within this scheme, we use master equations and derive various analytical estimates for the chemical equilibration times. Applying a Bjorken picture to the expanding fireball, the hadrons can, indeed, quickly chemically equilibrate for both an initial overpopulation or underpopulation of Hagedorn resonances. Our hadron resonance gas model, including the additional Hagedorn states, is used to obtain an upper bound on the shear viscosity to entropy density ratio, {eta}/s, of hadronic matter near T{sub c} that is close to 1/(4/{pi}). We show how the measured particle ratios can be used to provide non-trivial information about T{sub c} of the QCD phase transition. This is obtained by including the effects of highly massive Hagedorn resonances on statistical models, which are generally used to describe hadronic yields. The inclusion of the ''missing'' Hagedorn states

Searches for squarks and gluinos in fully hadronic final states with the ATLAS detector

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00023943; The ATLAS collaboration

2016-01-01

Despite the absence of experimental evidence, weak scale supersymmetry remains one of the best motivated and studied Standard Model extensions. The recent increase in the center of mass energy of the proton-proton collisions gives a unique opportunity to extend the sensitivity to production of supersymmetric particles at the Large Hadron Collider. We present results of two searches for squarks and gluinos using fully hadronic final states at sqrt(s) = 13 TeV with 10fb-1 of 2016 data collected by the ATLAS detector. These searches use three primary classes of event selection observables, including novel Recursive Jigsaw and Lorentz-boosted object reconstruction approaches.

Hadron-structure

International Nuclear Information System (INIS)

De, S.S.

1989-01-01

The paper deals with the space-time structure of the sub-atomic world and attempts to construct the fields of the constitutents of the hadrons. Then it is attempted to construct the fields of the hadrons from these micro-fields. (autho r). 24 refs

Prospects for heavy flavor physics at hadron colliders

International Nuclear Information System (INIS)

Butler, J.N.

1997-09-01

The role of hadron colliders in the observation and study of CP violation in B decays is discussed. We show that hadron collider experiments can play a significant role in the early studies of these phenomena and will play an increasingly dominant role as the effort turns towards difficult to measure decays, especially those of the B s meson, and sensitive searches for rare decays and subtle deviations from Standard Model predictions. We conclude with a discussion of the relative merits of hadron collider detectors with 'forward' vs 'central' rapidity coverage

Examination of models of knee in primary cosmic ray spectrum using gamma-hadron families

International Nuclear Information System (INIS)

Sveshnikova, L.G.; Managadze, A.K.; Roganova, T.M.; Mukhamedshin, R.A.

2005-01-01

Four models for describing the primary cosmic radiation (PCR) spectrum are proposed/ The examination of the PCR spectra models is carried out from the viewpoint of their consistency with the data on the gamma-hadron families for the threshold energies of 100 and 500 TeV. The maximum possible contribution of the superfamilies, originating from the primary nuclei, but not from the protons, is calculated [ru

Towards a Unified Quark-Hadron-Matter Equation of State for Applications in Astrophysics and Heavy-Ion Collisions

Directory of Open Access Journals (Sweden)

Niels-Uwe F. Bastian

2018-05-01

Full Text Available We outline an approach to a unified equation of state for quark-hadron matter on the basis of a Φ − derivable approach to the generalized Beth-Uhlenbeck equation of state for a cluster decomposition of thermodynamic quantities like the density. To this end we summarize the cluster virial expansion for nuclear matter and demonstrate the equivalence of the Green’s function approach and the Φ − derivable formulation. As an example, the formation and dissociation of deuterons in nuclear matter is discussed. We formulate the cluster Φ − derivable approach to quark-hadron matter which allows to take into account the specifics of chiral symmetry restoration and deconfinement in triggering the Mott-dissociation of hadrons. This approach unifies the description of a strongly coupled quark-gluon plasma with that of a medium-modified hadron resonance gas description which are contained as limiting cases. The developed formalism shall replace the common two-phase approach to the description of the deconfinement and chiral phase transition that requires a phase transition construction between separately developed equations of state for hadronic and quark matter phases. Applications to the phenomenology of heavy-ion collisions and astrophysics are outlined.

Factorization for short distance hadron-hadron scattering

International Nuclear Information System (INIS)

Collins, J.C.; Illinois Inst. of Tech., Chicago; Soper, D.E.; Sterman, G.

1985-01-01

We show that factorization holds at leading twist in the Drell-Yang cross section dsigma/dQ 2 dy and related inclusive hadron-hadron cross sections. We review the heuristic arguments for factorization, as well as the difficulties which must be overcome in a proof. We go on to give detailed arguments for the all order cancellation of soft gluons, and to show how this leads to factorization. (orig.)

Critical behavior of mean-field hadronic models for warm nuclear matter

International Nuclear Information System (INIS)

Silva, J.B.; Lourenco, O.; Delfino, A.; Martins, J.S. Sa; Dutra, M.

2008-01-01

We study a set of hadronic mean-field models in the liquid-gas phase transition regime and calculate their critical parameters. The discussion is unified by scaling the coexistence curves in terms of these critical parameters. We study the models close to spinodal points, where they also present critical behavior. Inspired by signals of criticality shown in fragmentation experiments, we analyze two different scenarios in which such behavior would be expected: (i) the stability limits of a metastable system with vanishing external pressure; and (ii) the critical point of a gas-liquid phase equilibrium system for which the Maxwell construction applies. Spinodal and coexistence curves show the regions in which model dependence arises. Unexpectedly, this model dependence does not manifest if one calculates the thermal incompressibility of the models

B → Kl{sup +}l{sup -} decay at large hadronic recoil

Energy Technology Data Exchange (ETDEWEB)

Khodjamirian, Alexander; Mannel, Thomas [Siegen University (Germany); Wang, Yuming [TUM (Germany)

2013-07-01

We predict the amplitude of the B → Kl{sup +}l{sup -} decay in the region of the dilepton invariant mass squared 0 < q{sup 2}≤ m{sup 2}{sub J/ψ}, that is, at large hadronic recoil. The B → K form factors entering the factorizable part of the decay amplitude are obtained from QCD light-cone sum rules. The nonlocal effects, generated by the four-quark and penguin operators combined with the electromagnetic interaction, are calculated at q{sup 2}<0, far below the hadronic thresholds. For hard-gluon contributions we employ the QCD factorization approach. The soft-gluon nonfactorizable contributions are estimated from QCD light-cone sum rules. The result of the calculation is matched to the hadronic dispersion relation in the variable q{sup 2}, which is then continued to the kinematical region of the decay. The overall effect of nonlocal contributions in B → Kl{sup +}l{sup -} at large hadronic recoil is moderate. The main uncertainty of the predicted B → Kl{sup +}l{sup -} partial width is caused by the B → K form factors. Furthermore, the isospin asymmetry in this decay is expected to be very small. We investigate the deviation of the observables from the Standard Model predictions by introducing a generic new physics contribution to the effective Hamiltonian.

Hadron mass corrections in semi-inclusive deep inelastic scattering

International Nuclear Information System (INIS)

Accardi, A.; Hobbs, T.; Melnitchouk, W.

2009-01-01

We derive mass corrections for semi-inclusive deep inelastic scattering of leptons from nucleons using a collinear factorization framework which incorporates the initial state mass of the target nucleon and the final state mass of the produced hadron h. The hadron mass correction is made by introducing a generalized, finite-Q 2 scaling variable ζ h for the hadron fragmentation function, which approaches the usual energy fraction z h = E h /ν in the Bjorken limit. We systematically examine the kinematic dependencies of the mass corrections to semi-inclusive cross sections, and find that these are even larger than for inclusive structure functions. The hadron mass corrections compete with the experimental uncertainties at kinematics typical of current facilities, Q 2 2 and intermediate x B > 0.3, and will be important to efforts at extracting parton distributions from semi-inclusive processes at intermediate energies.

Deep inelastic lepton-hadron processes in gauge models with massive vector gluons

International Nuclear Information System (INIS)

Morozov, P.T.; Stamenov, D.B.

1978-01-01

Considered is a class of strong interaction models in which the interactions between coloured quarks are mediated by massive neutral vector gluons. All the vector gluons acquire masses by the Higgs mechanism. These models are not asymptotically free. The effective gauge coupling constant anti α vanishes asymptotically, and the effective quartic coupling constant anti h tends to a finite asymptotic value. The behaviour of the moments of the deep inelastic lepton-hadron structure functions is analyzed. It is shown that the Bjorken scaling is violated by powers of logarithms

Conserved number fluctuations in a hadron resonance gas model

International Nuclear Information System (INIS)

Garg, P.; Mishra, D.K.; Netrakanti, P.K.; Mohanty, B.; Mohanty, A.K.; Singh, B.K.; Xu, N.

2013-01-01

Net-baryon, net-charge and net-strangeness number fluctuations in high energy heavy-ion collisions are discussed within the framework of a hadron resonance gas (HRG) model. Ratios of the conserved number susceptibilities calculated in HRG are being compared to the corresponding experimental measurements to extract information about the freeze-out condition and the phase structure of systems with strong interactions. We emphasize the importance of considering the actual experimental acceptances in terms of kinematics (pseudorapidity (η) and transverse momentum (p T )), the detected charge state, effect of collective motion of particles in the system and the resonance decay contributions before comparisons are made to the theoretical calculations. In this work, based on HRG model, we report that the net-baryon number fluctuations are least affected by experimental acceptances compared to the net-charge and net-strangeness number fluctuations

Design Study for a Staged Very Large Hadron Collider

Energy Technology Data Exchange (ETDEWEB)

Chao, Alex W.

2002-02-27

Particle physics makes its greatest advances with experiments at the highest energy. The only sure way to advance to a higher-energy regime is through hadron colliders--the Tevatron, the LHC, and then, beyond that, a Very Large Hadron Collider. At Snowmass-1996 [1], investigators explored the best way to build a VLHC, which they defined as a 100 TeV collider. The goals in this study are different. The current study seeks to identify the best and cheapest way to arrive at frontier-energy physics, while simultaneously starting down a path that will eventually lead to the highest-energy collisions technologically possible in any accelerator using presently conceivable technology. This study takes the first steps toward understanding the accelerator physics issues, the technological possibilities and the approximate cost of a particular model of the VLHC. It describes a staged approach that offers exciting physics at each stage for the least cost, and finally reaches an energy one-hundred times the highest energy currently achievable.

Testing Hadronic Interaction Models using a Highly Granular Silicon-Tungsten Calorimeter

CERN Document Server

Bilki, B.; Schlereth, J.; Xia, L.; Deng, Z.; Li, Y.; Wang, Y.; Yue, Q.; Yang, Z.; Eigen, G.; Mikami, Y.; Price, T.; Watson, N.K.; Thomson, M.A.; Ward, D.R.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Carloganu, C.; Chang, S.; Khan, A.; Kim, D.H.; Kong, D.J.; Oh, Y.D.; Blazey, G.C.; Dyshkant, A.; Francis, K.; Lima, J.G.R.; Salcido, P.; Zutshi, V.; Boisvert, V.; Green, B.; Misiejuk, A.; Salvatore, F.; Kawagoe, K.; Miyazaki, Y.; Sudo, Y.; Suehara, T.; Tomita, T.; Ueno, H.; Yoshioka, T.; Apostolakis, J.; Folger, G.; Ivantchenko, V.; Ribon, A.; Uzhinskiy, V.; Cauwenbergh, S.; Tytgat, M.; Zaganidis, N.; Hostachy, J.Y.; Morin, L.; Gadow, K.; Göttlicher, P.; Günter, C.; Krüger, K.; Lutz, B.; Reinecke, M.; Sefkow, F.; Feege, N.; Garutti, E.; Laurien, S.; Lu, S.; Marchesini, I.; Matysek, M.; Ramilli, M.; Kaplan, A.; Norbeck, E.; Northacker, D.; Onel, Y.; Kim, E.J.; van Doren, B.; Wilson, G.W.; Wing, M.; Bobchenko, B.; Chadeeva, M.; Chistov, R.; Danilov, M.; Drutskoy, A.; Epifantsev, A.; Markin, O.; Mizuk, R.; Novikov, E.; Popov, V.; Rusinov, V.; Tarkovsky, E.; Besson, D.; Popova, E.; Gabriel, M.; Kiesling, C.; Simon, F.; Soldner, C.; Szalay, M.; Tesar, M.; Weuste, L.; Amjad, M.S.; Bonis, J.; Callier, S.; Conforti di Lorenzo, S.; Cornebise, P.; Doublet, Ph.; Dulucq, F.; Faucci-Giannelli, M.; Fleury, J.; Frisson, T.; Kégl, B.; van der Kolk, N.; Li, H.; Martin-Chassard, G.; Richard, F.; de la Taille, Ch.; Pöschl, R.; Raux, L.; Rouëne, J.; Seguin-Moreau, N.; Anduze, M.; Balagura, V.; Becheva, E.; Boudry, V.; Brient, J.-C.; Cornat, R.; Frotin, M.; Gastaldi, F.; Magniette, F.; Matthieu, A.; Mora de Freitas, P.; Videau, H.; Augustin, J.-E.; David, J.; Ghislain, P.; Lacour, D.; Lavergne, L.; Zacek, J.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Ruzicka, P.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Jeans, D.; Götze, M.

2015-09-11

A detailed study of hadronic interactions is presented using data recorded with the highly granular CALICE silicon-tungsten electromagnetic calorimeter. Approximately 600,000 selected negatively changed pion events at energies between 2 and 10 GeV have been studied. The predictions of several physics models available within the GEANT4 simulation tool kit are compared to this data. Although a reasonable overall description of the data is observed, there are significant quantitative discrepancies in the longitudinal and transverse distributions of reconstructed energy.

Tests of Local Hadron Calibration Approaches in ATLAS Combined Beam Tests

International Nuclear Information System (INIS)

Grahn, Karl-Johan; Kiryunin, Andrey; Pospelov, Guennadi

2011-01-01

Three ATLAS calorimeters in the region of the forward crack at |η| 3.2 in the nominal ATLAS setup and a typical section of the two barrel calorimeters at |η| = 0.45 of ATLAS have been exposed to combined beam tests with single electrons and pions. Detailed shower shape studies of electrons and pions with comparisons to various Geant4 based simulations utilizing different physics lists are presented for the endcap beam test. The local hadron calibration approach as used in the full Atlas setup has been applied to the endcap beam test data. An extension of it using layer correlations has been tested with the barrel test beam data. Both methods utilize modular correction steps based on shower shape variables to correct for invisible energy inside the reconstructed clusters in the calorimeters (compensation) and for lost energy deposits outside of the reconstructed clusters (dead material and out-of-cluster deposits). Results for both methods and comparisons to Monte Carlo simulations are presented.

Hadron collider physics

Energy Technology Data Exchange (ETDEWEB)

Pondrom, L.

1991-10-03

An introduction to the techniques of analysis of hadron collider events is presented in the context of the quark-parton model. Production and decay of W and Z intermediate vector bosons are used as examples. The structure of the Electroweak theory is outlined. Three simple FORTRAN programs are introduced, to illustrate Monte Carlo calculation techniques. 25 refs.

Hadron collider physics

International Nuclear Information System (INIS)

Pondrom, L.

1991-01-01

An introduction to the techniques of analysis of hadron collider events is presented in the context of the quark-parton model. Production and decay of W and Z intermediate vector bosons are used as examples. The structure of the Electroweak theory is outlined. Three simple FORTRAN programs are introduced, to illustrate Monte Carlo calculation techniques. 25 refs

Deep-Inelastic Final States in a Space-Time Description of Shower Development and Hadronization

OpenAIRE

Ellis, John; Geiger, Klaus; Kowalski, Henryk

1996-01-01

We extend a quantum kinetic approach to the description of hadronic showers in space, time and momentum space to deep-inelastic $ep$ collisions, with particular reference to experiments at HERA. We follow the history of hard scattering events back to the initial hadronic state and forward to the formation of colour-singlet pre-hadronic clusters and their decays into hadrons. The time evolution of the space-like initial-state shower and the time-like secondary partons are treated similarly, an...

Investigation of tt-bar in the full hadronic final state at CDF with a neural network approach

International Nuclear Information System (INIS)

Sidoti, A.; Azzi, P.; Busetto, G.; Castro, A.; Dusini, S.; Lazzizzera, I.; Wyss, J.L.

2001-01-01

In this work we present the results of a neural network (NN) approach to the measurement of the tt-bar production cross-section and top mass in the all-hadronic channel, analyzing data collected at the Collider Detector at Fermilab (CDF) experiment. We have used a hardware implementation of a feed forward neural network, TOTEM, the product of a collaboration of INFN (Istituto Nazionale Fisica Nucleare) - IRST (Istituto per la Ricerca Scientifica e Tecnologica) - University of Trento, Italy. Particular attention has been paid to the evaluation of the systematics specifically related to the NN approach. The results are consistent with those obtained at CDF by conventional data selection techniques

Space-time aspects of hadronic cascading in lepton nucleus scattering

International Nuclear Information System (INIS)

Gyulassy, M.; Pluemer, M.

1989-05-01

A Monte Carlo model of hadronic cascading in inelastic lepton nucleus scattering is constructed to investigate space-time scenarios consistent with the momentum space description of string models of multiparticle production. The prospects for resolving the ambiguity inherent in the definition of a formation length for composite hadrons are emphasized. 15 refs., 13 figs

VNI version 4.1. Simulation of high-energy particle collisions in QCD: Space-time evolution of e+e-... A + B collisions with parton-cascades, cluster-hadronization, final-state hadron cascades

International Nuclear Information System (INIS)

Geiger, K.; Longacre, R.

1999-01-01

VNI is a general-purpose Monte-Carlo event-generator, which includes the simulation of lepton-lepton, lepton-hadron, lepton-nucleus, hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. It uses the real-time evolution of parton cascades in conjunction with a self-consistent hadronization scheme, as well as the development of hadron cascades after hadronization. The causal evolution from a specific initial state (determined by the colliding beam particles) is followed by the time-development of the phase-space densities of partons, pre-hadronic parton clusters, and final-state hadrons, in position-space, momentum-space and color-space. The parton-evolution is described in terms of a space-time generalization of the familiar momentum-space description of multiple (semi)hard interactions in QCD, involving 2 → 2 parton collisions, 2 → 1 parton fusion processes, and 1 → 2 radiation processes. The formation of color-singlet pre-hadronic clusters and their decays into hadrons, on the other hand, is treated by using a spatial criterion motivated by confinement and a non-perturbative model for hadronization. Finally, the cascading of produced prehadronic clusters and of hadrons includes a multitude of 2 → n processes, and is modeled in parallel to the parton cascade description. This paper gives a brief review of the physics underlying VNI, as well as a detailed description of the program itself. The latter program description emphasizes easy-to-use pragmatism and explains how to use the program (including simple examples), annotates input and control parameters, and discusses output data provided by it

Exploring the Quark-Gluon Content of Hadrons: From Mesons to Nuclear Matter

International Nuclear Information System (INIS)

Hrayr Matevosyan

2007-01-01

Even though Quantum Chromodynamics (QCD) was formulated over three decades ago, it poses enormous challenges for describing the properties of hadrons from the underlying quark-gluon degrees of freedom. Moreover, the problem of describing the nuclear force from its quark-gluon origin is still open. While a direct solution of QCD to describe the hadrons and nuclear force is not possible at this time, we explore a variety of developed approaches ranging from phenomenology to first principle calculations at one or other level of approximation in linking the nuclear force to QCD. The Dyson Schwinger formulation (DSE) of coupled integral equations for the QCD Green's functions allows a non-perturbative approach to describe hadronic properties, starting from the level of QCD n-point functions. A significant approximation in this method is the employment of a finite truncation of the system of DSEs, that might distort the physical picture. In this work we explore the effects of including a more complete truncation of the quark-gluon vertex function on the resulting solutions for the quark 2-point functions as well as the pseudoscalar and vector meson masses. The exploration showed strong indications of possibly large contributions from the explicit inclusion of the gluon 3- and 4-point functions that are omitted in this and previous analyses. We then explore the possibility of extrapolating state of the art lattice QCD calculations of nucleon form factors to the physical regime using phenomenological models of nucleon structure. Finally, we further developed the Quark Meson Coupling model for describing atomic nuclei and nuclear matter, where the quark-gluon structure of nucleons is modeled by the MIT bag model and the nucleon many body interaction is mediated by the exchange of scalar and vector mesons. This approach allows us to formulate a fully relativistic theory, which can be expanded in the nonrelativistic limit to reproduce the well known phenomenological Skyrme

Supersymmetry across the Hadronic Spectrum

Directory of Open Access Journals (Sweden)

Hans Günter Dosch

2017-01-01

Full Text Available Semiclassical light-front bound-state equations for hadrons are presented and compared with experiment. The essential dynamical feature is the holographic approach; that is, the hadronic equations in four-dimensional Minkowski space are derived as holograms of classical equations in a 5-dimensional anti-de Sitter space. The form of the equations is constrained by the imposed superconformal algebra, which fixes the form of the light-front potential. If conformal symmetry is strongly broken by heavy quark masses, the combination of supersymmetry and the classical action in the 5-dimensional space still fixes the form of the potential. By heavy quark symmetry, the strength of the potential is related to the heavy quark mass. The contribution is based on several recent papers in collaboration with Stan Brodsky and Guy de Téramond.

Electromagnetic moments of hadrons and quarks in a hybrid model

International Nuclear Information System (INIS)

Gerasimov, S.B.

1989-01-01

Magnetic moments of baryons are analyzed on the basis of general sum rules following from the theory of broken symmetries and quark models including the relativistic effects and hadronic corrections due to the meson exchange currents. A new sum rule is proposed for the hyperon magnetic moments, which is in accord with the most precise new data and also with a theory of the electromagnetic ΛΣ 0 mixing. The numerical values of the quark electromagnetic moments are obtained within a hybrid model treating the pion cloud effects through the local coupling of the pion field with the constituent massive quarks. Possible sensitivity of the weak neutral current magnetic moments to violation of the Okubo-Zweig-Izuki rule is emphasized nand discussed. 39 refs.; 1 fig

Space, time and color in hadron production via e+ e- --> Z$^{0}$ and e+ e- --> W$^{+}$W$^{-}$

CERN Document Server

Ellis, John R.; Ellis, John; Geiger, Klaus

1996-01-01

The time-evolution of jets in hadronic e+ e- events at LEP is investigated in both position- and momentum-space, with emphasis on effects due to color flow and particle correlations. We address dynamical aspects of the four simultanously-evolving, cross-talking parton cascades that appear in the reaction e+ e- --> .gamma./Z.sup(0) --> W+W- --> q1 q~2 q3 q~4, and compare with the familiar two-parton cascades in e+ e- --> Z.sup(0) --> q1 q~2. We use a QCD statistical transport approach, in which the multiparticle final state is treated as an evolving mixture of partons and hadrons, whose proportions are controlled by their local space-time geography via standard perturbative QCD parton shower evolution and a phenomenological model for non-perturbative parton-cluster formation followed by cluster decays into hadrons. Our numerical simulations exhibit a characteristic "inside-outside" evolution simultanously in position and momentum space. We compare three different model treatments of color flow, and find large ...

Polarization effects in hadron fragmentation

International Nuclear Information System (INIS)

Lednicky, R.

1984-01-01

Hadron polarization (spin alignment) and polarization asymmetry are discussed in terms of the quark recombination model with the spin-orbit interaction taken into account. It is shown that predictions of this model are at least in qualitative agreement with experimental data. Various polarization mechanisms in terms of this model and the possibility of their checking are also discussed

Statistical fluctuations and correlations in hadronic equilibrium systems

International Nuclear Information System (INIS)

Hauer, Michael

2010-01-01

This thesis is dedicated to the study of fluctuation and correlation observables of hadronic equilibrium systems. The statistical hadronization model of high energy physics, in its ideal, i.e. non-interacting, gas approximation is investigated in different ensemble formulations. The hypothesis of thermal and chemical equilibrium in high energy interaction is tested against qualitative and quantitative predictions. (orig.)

Statistical fluctuations and correlations in hadronic equilibrium systems

Energy Technology Data Exchange (ETDEWEB)

Hauer, Michael

2010-06-17

This thesis is dedicated to the study of fluctuation and correlation observables of hadronic equilibrium systems. The statistical hadronization model of high energy physics, in its ideal, i.e. non-interacting, gas approximation is investigated in different ensemble formulations. The hypothesis of thermal and chemical equilibrium in high energy interaction is tested against qualitative and quantitative predictions. (orig.)

Problems of hadron electrodynamics

International Nuclear Information System (INIS)

Rekalo, M.P.

1989-01-01

Certain directions of hadron electrodynamics referring to testing symmetry properties relatively to C-, P- and T-transformations; determination of fundamental electromagnetic characteristics of hadrons as well as to clarifying the dynamics of electromagnetic processes in which hadrons participate are analyzed briefly. 52 refs

Latest results on b-hadron spectroscopy at LHCb

CERN Multimedia

CERN. Geneva

2015-01-01

Hadrons are systems bound by the strong interaction, which is described at the fundamental level by Quantum Chromodynamics (QCD). While QCD is well understood at high energy in the perturbative regime, low-energy phenomena such as the binding of quarks and gluons within hadrons are more difficult to predict. High precision measurements are most useful to test the reliability of several models and techniques, such as constituent-quark models or lattice-QCD calculations, into predicting the mass spectrum and the properties of the hadrons. Using 3.0/fb of integrated luminosity recorded by the LHCb experiment, we report precise measurements of the B1(5721){0,+} and B2*(5747){0,+} states and the observation of B{+,0} pi{-,+} mass structures. The observations of two new Xib baryons are presented as well.

High energy hadron-nucleus collision

International Nuclear Information System (INIS)

Takagi, Fujio

1983-02-01

This is a lecture note concerning high energy hadron-nucleus collision. The lecture gives the inelastic total cross section and the Glanber approximate multiple scattering formula at first. The mechanism of nuclear spallation is described in a cylindrical image. The multiplicity, the one particle distribution and the time-space structure of particle production are discussed. Various models are presented. The attenuation of forward particles and the structure of hadrons are discussed for each model. The atomic number (A) dependence of the production of large transverse momentum particles and jet, and the A dependence of charged multiplicity are presented. The backward production of particles and many body correlation are discussed. Lepton pair production and the initial interaction of constituents, collective interaction, multi quark state and phase transition are described. (Kato, T.)

CMS Central Hadron Calorimeter

OpenAIRE

Budd, Howard S.

2001-01-01

We present a description of the CMS central hadron calorimeter. We describe the production of the 1996 CMS hadron testbeam module. We show the results of the quality control tests of the testbeam module. We present some results of the 1995 CMS hadron testbeam.

Signatures of parton exogamy in e+e- → W+W- → hadrons

Science.gov (United States)

Ellis, John; Geiger, Klaus

1997-02-01

We propose possible signatures of ‘exogamous’ combinations between partons in the different W+ and W- hadron showers in e+e- → W+W- events with purely hadronic final states. Within the space-time model for hadronic shower development that we have proposed previously, we find a possible difference of about 10% between the mean hadronic multiplicity in such purely hadronic final states and twice the hadronic multiplicity in events in which one W± decays hadronically and the other leptonically, i.e., « Nhad(2 W ≠ 2« Nhad( W), associated with the formation of hadronic clusters by ‘exogamous’ pairs of partons. We discuss the dependence of this possible difference in multiplicity on the center-of-mass energy, on the hadron momenta, and on the angular separation between the W± dijets. If it were observed, any such multiplicity difference would indicate that the W± do not hadronize independently, and hence raise questions about the accuracy with which the W± mass could be determined from purely hadronic final states.

Some experimental results of the investigation of hadron-nucleus and nucleus-nucleus interactions

International Nuclear Information System (INIS)

Azimov, S.A.; Gulamov, K.G.; Chernov, G.M.

1978-01-01

Recent experimental data on the hadron-nucleus and nucleus-nucleus inelastic interactions are analyzed. A particular attention is paid to the description of the leading hadron spectra and of the spectra of nucleon recoils in hadron-nucleus interactions. Some of the results of the experimental studies of correlations between secondary particles are discussed. This discussion demonstrates that an analysis of the multiparticle phenomena is very promising regarding the discrimination between the different models for the hadron-nucleus and nucleus-nucleus interactions. It is pointed out that the actual mechanism of the hadron-nucleus and nucleus-nucleus interactions is a rather complex one and can be described comprehensively by none of the existing models

Hadronic production of massive lepton pairs

International Nuclear Information System (INIS)

Berger, E.L.

1982-12-01

A review is presented of recent experimental and theoretical progress in studies of the production of massive lepton pairs in hadronic collisions. I begin with the classical Drell-Yan annihilation model and its predictions. Subsequently, I discuss deviations from scaling, the status of the proofs of factorization in the parton model, higher-order terms in the perturbative QCD expansion, the discrepancy between measured and predicted yields (K factor), high-twist terms, soft gluon effects, transverse-momentum distributions, implications for weak vector boson (W +- and Z 0 ) yields and production properties, nuclear A dependence effects, correlations of the lepton pair with hadrons in the final state, and angular distributions in the lepton-pair rest frame

Signatures of chromodynamics in hadron collisions

International Nuclear Information System (INIS)

Halzen, F.

1979-01-01

The quantum chromodynamics (QCD) describes the interaction of the parton constituents of hadrons (quarks and gluons) via eight colored photons (gluons) interacting with the quarks, and unlike the photons, with each other. The simple picture of Drell-Yan model has made surprising success. The marriage of the old fashion Drell-Yan parton model with QCD has not only made its phenomenological success in the study of lepton pair production, but has allowed to study quantitatively the gluon correction to the model. Information from beam dump and emulsion experiments on charm production is compared with the typical QCD diagram. The results indicate some possible non-perturbative contribution to the photon- and hadron-production of heavy quarks. The definite features of dilepton as well as large transverse momentum data are direct signature of gluons. (Kato, T.)

The hadronic final state in the deep inelastic electron-proton scattering. A comparison between the ZEUS data measured 1992 and theoretical models

International Nuclear Information System (INIS)

Schneider, J.L.

1993-12-01

The hadronic final state in deep inelastic e - P collisions has been studied with the 1992 data from the ZEUS detector at HERA. The hadronic final state is described by event topology variables like thrust and sphericity and also by variables like multiplicity and transverse momentum. These quantities require the reconstruction of the particle four moments which are calculated from calorimeter cell clusters (condensates). A detailed Monte-Carlo comparison between final state particles and condensates is presented. ZEUS data and model predictions are compared in the γ * P system. Good agreement between data and models is found in the x-Feynman and transverse momentum spectra and in the seagull plot. Mean thrust and sphericity are measured as functions of the invariant mass W of the hadronic final state. They significantly deviate from the model predictions, as do the mean multiplicities, which exceed the model predictions by about 1 unit. (orig.)

Identification of hadronic tau decays at the ATLAS detector using artificial neural networks

Energy Technology Data Exchange (ETDEWEB)

Duschinger, Dirk; Hanisch, Stefanie; Mader, Wolfgang; Madysa, Nico; Straessner, Arno [Institut fuer Kern- und Teilchenphysik, TU Dresden (Germany)

2016-07-01

One of the primary goals of the ATLAS experiment at the LHC is the search for physics beyond the Standard Model. The efficient identification of hadronically decaying tau leptons is crucial for this as they comprise the final states of several decay channels sensitive to new physics. (e. g. Higgs boson decays H → τ{sub had} τ{sub had}) The identification algorithm currently applied at ATLAS utilizes multi-variate methods and reconstructed particle properties to discriminate against QCD jets, which constitute an important background. This talk presents a new neural-network-based approach to hadronic tau decay identification and investigates its dependence on hyperparameters such as the network topology or number of training cycles. Ensembling is presented as a technique to improve classifier performance and robustness against overtraining. The resulting classifier is compared to the current approach based on Boosted Decision Trees. The study is based on 2012 data taken at the ATLAS detector at a center-of-mass energy of √(s)=8 TeV.

On slow particle production in hadron-nucleus interactions

International Nuclear Information System (INIS)

Stenlund, E.; Otterlund, I.

1982-01-01

A model for slow particle production in hadron-nucleus interactions is presented. The model succesfully predicts correlations between the number of knock-on particles and the number of particles associated with the evaporation process as well as correlations with the number of collisions, ν, between the incident hadron and the nucleons inside the target nucleus. The model provides two independent possibilities to determine the number of primary intranuclear collisions, ν, i.e. by its correlation to the number of knock-on particles or to the number of evaporated particles. The good agreement indicates that the model gives an impact-parameter sensitive description of hardron nucleus reactions. (orig.)

Investigation of hadronic structure by solving QCD on a lattice

International Nuclear Information System (INIS)

Grandy, J.M.

1992-01-01

Various aspects of hadronic structure are investigated by means of lattice calculations. The measurements focus on equal-time quark wavefunctions, correlations of density operators, and vacuum correlators of hadronic currents, with additional measurements of Wilson loops and hadron masses as a consistency check. The wavefunctions are shown to be consistent with a confinement model prediction. The effect of hyperfine splitting on the wavefunctions is shown to agree closely with the quark model prediction. The computed quark density correlations for the pion, rho, and proton at long range are compared with the expected asymptotic behavior. The density correlation also provides a basis for comparing the spatial extent of quark pairs surrounding the hadron with the extent of the valence quark wavefunction. Vacuum correlation functions of hadronic currents are compared with phenomenological fits to experimental data and sum rule calculations. Hadronic observable calculations are performed by evaluating path integrals in imaginary time using a Monte Carlo technique. Lattices with 16 points in the time direction and spatial volume of 12 3 and 16 3 points are used. The physical lattice spacing is 0.2 fm, and the physical volume of the lattice is large enough that the effect of spatial boundary conditions on the long range structure of the particles can be corrected in a linear fashion

Quark–hadron phase structure, thermodynamics, and magnetization of QCD matter

Science.gov (United States)

Nasser Tawfik, Abdel; Magied Diab, Abdel; Hussein, M. T.

2018-05-01

The SU(3) Polyakov linear-sigma model (PLSM) is systematically implemented to characterize the quark-hadron phase structure and to determine various thermodynamic quantities and the magnetization of quantum chromodynamic (QCD) matter. Using mean-field approximation, the dependence of the chiral order parameter on a finite magnetic field is also calculated. Under a wide range of temperatures and magnetic field strengths, various thermodynamic quantities including trace anomaly, speed of sound squared, entropy density, and specific heat are presented, and some magnetic properties are described as well. Where available these results are compared to recent lattice QCD calculations. The temperature dependence of these quantities confirms our previous finding that the transition temperature is reduced with the increase in the magnetic field strength, i.e. QCD matter is characterized by an inverse magnetic catalysis. Furthermore, the temperature dependence of the magnetization showing that QCD matter has paramagnetic properties slightly below and far above the pseudo-critical temperature is confirmed as well. The excellent agreement with recent lattice calculations proves that our QCD-like approach (PLSM) seems to possess the correct degrees of freedom in both the hadronic and partonic phases and describes well the dynamics deriving confined hadrons to deconfined quark-gluon plasma.

Topological objects in hadron physics

International Nuclear Information System (INIS)

Rho, M.

1988-01-01

The notion of topological objects in hadronic physics is discussed, with emphasis on the role of the Wess-Zumino term and induced transmutation of quantum numbers in chiral bag models. Some applications to nuclear systems are given

Flavor production in PB(160 AGEV) on PB collisions: Effect of color ropes and hadronic rescattering

International Nuclear Information System (INIS)

Sorge, H.

1995-09-01

Collective interactions in the preequilibrium quark matter and hadronic resonance gas stage of ultrarelativistic nucleus-nucleus collisions are studied in the framework fo the transport theoretical approach RQMD. The paper reviews string fusion into color ropes and hadronic rescattering which serve as models for these interactions. Hadron production in central Pb(160 AGeV) on Pb collisions has been calculated. The changes of the final flavor composition are more pronounced than in previous RQMD studies of light ion induced reactions at 200 AGeV. The ratio of created quark pairs s anti s/(u anti u+d anti d) is enhanced by a factor of 2.4 in comparison to pp results. Color rope formation increases the initially produced antibaryons to 3 times the value in the 'NN mode', but only one quarter of the produced antibaryons survives because of subsequent strong absorption. The differences in the final particle composition for Pb on Pb collisions compared to S induced reactions are attributed to the hadronic resonance gas stage which is baryon-richer and lasts longer. (orig.)

A constituent quark model with colour degrees of freedom confronts the data on hadron-nucleus interactions

International Nuclear Information System (INIS)

Rozanska, M.; Jezabek, M.

1991-04-01

Three version of a model with colour excitations of constituent quarks are examined using inclusive leading proton and antiproton spectra in nuclear interactions at high energies. The comparison with experimental data excludes the models in which fragmentation into leading final hadrons depends only on the colour charge of constituents in an intermediate system. (author)

Search for charmless decays of B hadrons in hadronic and radiative (b --> s gamma) decay modes using the DELPHI detector

CERN Document Server

Liko, Dietrich

1995-01-01

Charmless decays of B hadrons have been of considerable interest during the last years. Decays in hadronic modes proceed either trough tree level b � u transitions or loop diagrams involving so-called "hadronic" penguins. Tree level dominated decays confirm the non zero value of JVubl in the CKM mixing matrix while those induced by penguin processes provide tests of the loop structure of the Standard Model. Decays in the radiative modes b -+ s-y are forbidden at tree level and proceed only trough loop diagrams. Possible contributions to the decay rate due to new physics provide a test of the Standard Model. During the last years various measurements of decay rates have been performed at colliders at the bb-threshold. Experiments at the LEP collider have already collected sufficient data to study these decays in a different experimental environment. Results of searches at the DELPHI experiment are presented.

Hydrodynamic approach to the centrality dependence of di-hadron correlations

Science.gov (United States)

Castilho, Wagner M.; Qian, Wei-Liang; Gardim, Fernando G.; Hama, Yogiro; Kodama, Takeshi

2017-06-01

Measurements of di-hadron azimuthal correlations at different centralities for Au+Au collisions at 200 A GeV were reported by the PHENIX Collaboration. The data were presented for different ranges of transverse momentum. In particular, it was observed that the away-side correlation evolves from a double- to a single-peak structure when the centrality decreases. In this work, we show that these features naturally appear due to an interplay between the centrality-dependent smooth background elliptic flow and the one produced by event-by-event fluctuating peripheral tubes. To compare with the PHENIX data, we also carry out numerical simulations by using a hydrodynamical code nexspherio, and calculate the correlations by both cumulant and the ZYAM method employed by the PHENIX Collaboration. Our results are in reasonable agreement with the data. A brief discussion on the physical content of the present model and its difference from other viewpoints is also presented.

Triggering on hadronic tau decays: ATLAS meets the challenge

Indian Academy of Sciences (India)

Hadronic tau decays play a crucial role in taking Standard Model (SM) measurements as well as in the search for physics beyond the SM. However, hadronic tau decays are difficult to identify and trigger on due to their resemblance to QCD jets. Given the large production crosssection of QCD processes, designing and ...

Hadrons in dense and/or hot hadronic matter

International Nuclear Information System (INIS)

Bertrand, T.; Chanfray, G.; Davesne, D.; Delorme, J.; Ericson, M.; Marteau, J.

1998-01-01

Medium effects on various properties of hadrons have been considered. We have studied the mixing between axial and vector currents which accompanies the partial restoration of chiral symmetry. We have improved in several ways our interpretation of the modifications of the ρ mass spectrum in the CERN heavy ion experiment CERES. Still in the domain of relativistic heavy ion collisions, a Boltzmann transport equation has been solved with the aim of incorporating medium effects on the pion spectra. More formally, studies have been conducted with promising results on non perturbative methods in field theory. Other topics cover nuclear effects in the atmospheric neutrino problem and a semi-classical approach to exclusive (e,e'p) reactions. (authors)

Momentum space dipole amplitude for DIS and inclusive hadron production

Energy Technology Data Exchange (ETDEWEB)

Basso, E. A.; Gay Ducati, M. B. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970 - Porto Alegre, RS (Brazil); De Oliveira, E. G. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05314-970 Sao Paulo, SP (Brazil)

2013-03-25

We show how the AGBS model, originally developed for deep inelastic scattering applied to HERA data on the proton structure function, can also describe the RHIC data on single inclusive hadron yield for d+Au and p+p collisions through a new simultaneous fit. The single inclusive hadron production is modeled through the color glass condensate, which uses the quark(and gluon) condensate amplitudes in momentum space. The AGBS model is also a momentum space model based on the asymptotic solutions of the BK equation, although a different definition of the Fourier transform is used. This description entirely in transverse momentum of both processes arises for the first time. The small difference between the simultaneous fit and the one for HERA data alone suggests that the AGBS model describes very well both kind of processes and thus emerges as a good tool to investigate the inclusive hadron production data. We use this model for predictions at LHC energies, which agree quite well with available experimental data.

Momentum space dipole amplitude for DIS and inclusive hadron production

International Nuclear Information System (INIS)

Basso, E. A.; Gay Ducati, M. B.; De Oliveira, E. G.

2013-01-01

We show how the AGBS model, originally developed for deep inelastic scattering applied to HERA data on the proton structure function, can also describe the RHIC data on single inclusive hadron yield for d+Au and p+p collisions through a new simultaneous fit. The single inclusive hadron production is modeled through the color glass condensate, which uses the quark(and gluon) condensate amplitudes in momentum space. The AGBS model is also a momentum space model based on the asymptotic solutions of the BK equation, although a different definition of the Fourier transform is used. This description entirely in transverse momentum of both processes arises for the first time. The small difference between the simultaneous fit and the one for HERA data alone suggests that the AGBS model describes very well both kind of processes and thus emerges as a good tool to investigate the inclusive hadron production data. We use this model for predictions at LHC energies, which agree quite well with available experimental data.

Plasma production and hadronization in ultrarelativistic nuclear collisions

International Nuclear Information System (INIS)

Kataja, M.

1990-01-01

We study the color confinement and hadronization in the thermodynamic limit of the flux tube model, which was recently developed to describe the energy deposition, particle production and the early expansion of plasma in the central region of ultrarelativistic heavy ion collisions. In this purpose, we introduce a concept of an intermediate 'mixed state', which is formed when the original giant flux tube is fragmented into many smaller tubes which contain the plasma and the Abelian color-electric field and which coexist with a dilute hadron gas. This mixed state is an extension of the mixed phase used in the pure hydrodynamic description utilizing the bag equation of state. We study the thermodynamics of this mixed state making use of the bag model and the classical models of color confinement. It appears that in the thermodynamic limit, the mixed state can be considered as a dielectric medium in which the color dielectric constant takes the values between 0 and 1. We also study how the 'equations of electrohydrodynamics', which were formulated in earlier works to describe the evolution of the giant flux tube and plasma, are to be modified due to the dielectric nature of the new transient mixed state. A numeric simulation of a one-dimensional scaling expansion demonstrates the dynamic transition of the system from plasma to hadron phase and the characteristic reheating effect due to this hadronization transition. It is also shown that in the limit of low temperature or large bag constant, this formalism is reduced to the hydrodynamics of hadron gas produced by the fragmentation of multiple strings. (orig.)

Hadron shower decomposition in the highly granular CALICE analogue hadron calorimeter

International Nuclear Information System (INIS)

Eigen, G.; Price, T.; Watson, N. K.; Marshall, J. S.; Thomson, M. A.; Ward, D. R.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Apostolakis, J.; Dotti, A.; Folger, G.; Ivantchenko, V.; Ribon, A.; Uzhinskiy, V.; Hostachy, J.-Y.; Morin, L.; Brianne, E.; Ebrahimi, A.; Gadow, K.

2016-01-01

The spatial development of hadronic showers in the CALICE scintillator-steel analogue hadron calorimeter is studied using test beam data collected at CERN and FNAL for single positive pions and protons with initial momenta in the range of 10–80 GeV/ c . Both longitudinal and radial development of hadron showers are parametrised with two-component functions. The parametrisation is fit to test beam data and simulations using the QGSP-BERT and FTFP-BERT physics lists from GEANT4 version 9.6. The parameters extracted from data and simulated samples are compared for the two types of hadrons. The response to pions and the ratio of the non-electromagnetic to the electromagnetic calorimeter response, h / e , are estimated using the extrapolation and decomposition of the longitudinal profiles.

Hadron shower decomposition in the highly granular CALICE analogue hadron calorimeter

CERN Document Server

Eigen, G.; Watson, N.K.; Marshall, J.S.; Thomson, M.A.; Ward, D.R.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Apostolakis, J.; Dotti, A.; Folger, G.; Ivantchenko, V.; Ribon, A.; Uzhinskiy, V.; Hostachy, J.Y.; Morin, L.; Brianne, E.; Ebrahimi, A.; Gadow, K.; Göttlicher, P.; Günter, C.; Hartbrich, O.; Hermberg, B.; Irles, A.; Krivan, F.; Krüger, K.; Kvasnicka, J.; Lu, S.; Lutz, B.; Morgunov, V.; Neubüser, C.; Provenza, A.; Reinecke, M.; Sefkow, F.; Schuwalow, S.; Tran, H.L.; Garutti, E.; Laurien, S.; Matysek, M.; Ramilli, M.; Schröder, S.; Briggl, K.; Eckert, P.; Munwes, Y.; Schultz-Coulon, H.-Ch.; Shen, W.; Stamen, R.; Bilki, B.; Norbeck, E.; Northacker, D.; Onel, Y.; Doren, B.van; Wilson, G.W.; Kawagoe, K.; Hirai, H.; Sudo, Y.; Suehara, T.; Sumida, H.; Takada, S.; Tomita, T.; Yoshioka, T.; Wing, M.; Bonnevaux, A.; Combaret, C.; Caponetto, L.; Grenier, G.; Han, R.; Ianigro, J.C.; Kieffer, R.; Laktineh, I.; Lumb, N.; Mathez, H.; Mirabito, L.; Steen, A.; Antequera, J.Berenguer; Alamillo, E.Calvo; Fouz, M.C.; Marin, J.; Puerta-Pelayo, J.; Verdugo, A.; Bobchenko, B.; Markin, O.; Novikov, E.; Rusinov, V.; Tarkovsky, E.; Kirikova, N.; Kozlov, V.; Smirnov, P.; Soloviev, Y.; Besson, D.; Buzhan, P.; Chadeeva, M.; Danilov, M.; Drutskoy, A.; Ilyin, A.; Mironov, D.; Mizuk, R.; Popova, E.; Gabriel, M.; Goecke, P.; Kiesling, C.; der Kolk, N.van; Simon, F.; Szalay, M.; Bilokin, S.; Bonis, J.; Cornebise, P.; Pöschl, R.; Richard, F.; Thiebault, A.; Zerwas, D.; Anduze, M.; Balagura, V.; Becheva, E.; Boudry, V.; Brient, J.C.; Cizel, J.B.; Clerc, C.; Cornat, R.; Frotin, M.; Gastaldi, F.; Magniette, F.; de Freitas, P.Mora; Musat, G.; Pavy, S.; Rubio-Roy, M.; Ruan, M.; Videau, H.; Callier, S.; Dulucq, F.; Martin-Chassard, G.; Raux, L.; Seguin-Moreau, N.; Taille, Ch.de la; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Kotera, K.; Ono, H.; Takeshita, T.; Ieki, S.; Kamiya, Y.; Ootani, W.; Shibata, N.; Jeans, D.; Komamiya, S.; Nakanishi, H.

2016-06-23

The spatial development of hadronic showers in the CALICE scintillator-steel analogue hadron calorimeter is studied using test beam data collected at CERN and FNAL for single positive pions and protons with initial momenta in the range from 10 to 80 GeV/c. Both longitudinal and radial development of hadron showers are parametrised with two-component functions. The parametrisation is fit to test beam data and simulations using the QGSP_BERT and FTFP_BERT physics lists from Geant4 version 9.6. The parameters extracted from data and simulated samples are compared for the two types of hadrons. The response to pions and the ratio of the non-electromagnetic to the electromagnetic calorimeter response, h/e, are estimated using the extrapolation and decomposition of the longitudinal profiles.

W-jet tagging: Optimizing the identification of boosted hadronically-decaying W bosons

International Nuclear Information System (INIS)

Cui Yanou; Han Zhenyu; Schwartz, Matthew D.

2011-01-01

A method is proposed for distinguishing highly boosted hadronically-decaying W's (W jets) from QCD-jets using jet substructure. Previous methods, such as the filtering/mass-drop method, can give a factor of ∼2 improvement in S/√(B) for jet p T > or approx. 200 GeV. In contrast, a multivariate approach including new discriminants such as R cores, which characterize the shape of the W jet, subjet planar flow, and grooming-sensitivities is shown to provide a much larger factor of ∼5 improvement in S/√(B). For longitudinally polarized W's, such as those coming from many new physics models, the discrimination is even better. Comparing different Monte Carlo simulations, we observe a sensitivity of some variables to the underlying event; however, even with a conservative estimates, the multivariate approach is very powerful. Applications to semileptonic WW resonance searches and all-hadronic W+jet searches at the LHC are also discussed. Code implementing our W-jet tagging algorithm is publicly available at http://jets.physics.harvard.edu/wtag.

Hadronic models and experimental data for the neutrino beam production

CERN Document Server

Collazuol, G; Guglielmi, A M; Sala, P R

2000-01-01

The predictions of meson production by 450 GeV/c protons on Be using the Monte Carlo FLUKA standalone and GEANT-FLUKA and GEANT-GHEISHA in GEANT are compared with available experimental measurements. The comparison enlightens the improvements of the hadronic generator models of the present standalone code FLUKA with respect to the 1992 version which is embedded into GEANT-FLUKA. Worse results were obtained with the GHEISHA package. A complete simulation of the SPS neutrino beam line at CERN showed significant variations in the intensity and composition of the neutrino beam when FLUKA standalone instead of the GEANT-FLUKA package is used to simulate particle production in the Be target.

Hadronic models and experimental data for the neutrino beam production

International Nuclear Information System (INIS)

Collazuol, G.; Ferrari, A.; Guglielmi, A.; Sala, P.R.

2000-01-01

The predictions of meson production by 450 GeV/c protons on Be using the Monte Carlo FLUKA standalone and GEANT-FLUKA and GEANT-GHEISHA in GEANT are compared with available experimental measurements. The comparison enlightens the improvements of the hadronic generator models of the present standalone code FLUKA with respect to the 1992 version which is embedded into GEANT-FLUKA. Worse results were obtained with the GHEISHA package. A complete simulation of the SPS neutrino beam line at CERN showed significant variations in the intensity and composition of the neutrino beam when FLUKA standalone instead of the GEANT-FLUKA package is used to simulate particle production in the Be target

Hadronic resonances at FAIR energies

International Nuclear Information System (INIS)

Vogel, Sascha

2013-01-01

These proceedings cover the analysis of hadronic resonances in heavy ion collisions. The model used for these studies is the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model. The model will be briefly explained, resonance observables will be highlighted and various kinematical issues will be investigated. Special emphasis will be put on the FAIR energy regime, especially highlighting the Compressed Baryonic Matter (CBM) program.

Hadron spectroscopy 1987

Energy Technology Data Exchange (ETDEWEB)

Anon.

1987-09-15

With much particle physics research using particle beams to probe the behaviour of the quark constituents deep inside nucleons and other strongly interacting particles (hadrons), it is easy to overlook the progress being made through hadron spectroscopy – the search for and classification of rare particles – and the way it has increased our understanding of quark physics. One way of remedying this was to attend the stimulating and encouraging Hadron 87 meeting held earlier this year at the Japanese KEK Laboratory, where Jonathan Rosner from Chicago's Enrico Fermi Institute gave the concluding talk.

Interactions between hadrons and nuclei. The Lund Monte Carlo - FRITIOF VERSION 1.6

International Nuclear Information System (INIS)

Nilsson-Almqvist, B.; Stenlund, E.

1986-08-01

This paper presents a Monte Carlo programme based upon a model, in which a hadron is treated as a vortex line in a superconducting vacuum. The vortex line consists of a hard core which is surrounded by an exponentially damped field. In a soft interaction a momentum transfer between two colliding hadrons is assumed to be due to the overlap of those fields. Having transferred momenta we end up with two longitudinally excited string states which finally fragment into hadrons. When the model is extended into hadron-nucleus and nucleus-nucleus interactions, the incoming hadrons may collide more than once and the excited states continue to collide during their passage through the nucleus. The model shows good agreement with data. FRITIOF 1.6 consists of a main programme where the variables are set and where the user handles the information. Information on the generated event and on the produced particles are stored in common blocks which make the information easy to handle. Furthermore FRITIOF 1.6 contains a set of subroutines for internal use, which administrates the event, gives masses to the excited nucleons etc. The hadronization and the particle decays are taken care of by routines in JETSET 6.2, which perform the hadronization according to the Lund Model for jet fragmentation. The programme is written in FORTRAN 77 and the only non-standard function needed to run the programme is a random number generator, which supplies uniformly distributed random numbers between 0 and 1

Extended hadron and two-hadron operators of definite momentum for spectrum calculations in lattice QCD

CERN Document Server

Morningstar, C; Fahy, B; Foley, J; Jhang, Y C; Juge, K J; Lenkner, D; Wong, C C H

2013-01-01

Multi-hadron operators are crucial for reliably extracting the masses of excited states lying above multi-hadron thresholds in lattice QCD Monte Carlo calculations. The construction of multi-hadron operators with significant coupling to the lowest-lying states of interest involves combining single hadron operators of various momenta. The design and implementation of large sets of spatially-extended single-hadron operators of definite momentum and their combinations into two-hadron operators are described. The single hadron operators are all assemblages of gauge-covariantly-displaced, smeared quark fields. Group-theoretical projections onto the irreducible representations of the symmetry group of a cubic spatial lattice are used in all isospin channels. Tests of these operators on 24^3 x 128 and 32^3 x 256 anisotropic lattices using a stochastic method of treating the low-lying modes of quark propagation which exploits Laplacian Heaviside quark-field smearing are presented. The method provides reliable estimat...

Measurements on hadron production in proton-proton collisions with the ATLAS detector

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00306374; The ATLAS collaboration

2018-01-01

Studies of correlated hadron production are an important source of information about the early stages of hadron formation, not yet understood from first principles. Although experimental high energy physics employs several semiclassical models of hadronization which describe the formation of jets with remarkable accuracy, correlation phenomena are more elusive. In this proceeding, we will discuss Bose-Einstein correlations measured with the ATLAS detector at the LHC and provide a unique opportunity for detailed understanding of the space-time geometry of the hadronization region.

Chiral symmetry and dispersion relations: from $\\pi \\pi$ scattering to hadronic light-by-light.

CERN Multimedia

CERN. Geneva

2018-01-01

Chiral symmetry provides strong constraints on hadronic matrix elements at low energy, which are most efficiently derived with chiral perturbation theory. As an effective quantum field theory the latter also accounts for rescattering or unitarity effects, albeit only perturbatively, via the loop expansion. In cases where rescattering effects are important it becomes necessary to go beyond the perturbative expansion, e.g. by using dispersion relations. A matching between the chiral and the dispersive representation provides in several cases results of high precision. I will discuss this approach with the help of a few examples, like $\\pi \\pi$ scattering (which has been tested successfully by CERN experiments like NA48/2 and DIRAC), $\\eta \\to 3 \\pi$ and the hadronic light-by-light contribution to $(g-2)_\\mu$. For the latter quantity the implementation of the dispersive approach has opened up the way to a model-independent calculation and the concrete possibility to significantly reduce the theoretical uncertain...

VNI version 4.1. Simulation of high-energy particle collisions in QCD: Space-time evolution of e{sup +}e{sup {minus}}...A + B collisions with parton-cascades, cluster-hadronization, final-state hadron cascades

Energy Technology Data Exchange (ETDEWEB)

Geiger, K.; Longacre, R. [Brookhaven National Lab., Upton, NY (United States). Physics Dept.; Srivastava, D.K. [Variable Energy Cyclotron Centre, Calcutta (India)

1999-02-01

VNI is a general-purpose Monte-Carlo event-generator, which includes the simulation of lepton-lepton, lepton-hadron, lepton-nucleus, hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. It uses the real-time evolution of parton cascades in conjunction with a self-consistent hadronization scheme, as well as the development of hadron cascades after hadronization. The causal evolution from a specific initial state (determined by the colliding beam particles) is followed by the time-development of the phase-space densities of partons, pre-hadronic parton clusters, and final-state hadrons, in position-space, momentum-space and color-space. The parton-evolution is described in terms of a space-time generalization of the familiar momentum-space description of multiple (semi)hard interactions in QCD, involving 2 {r_arrow} 2 parton collisions, 2 {r_arrow} 1 parton fusion processes, and 1 {r_arrow} 2 radiation processes. The formation of color-singlet pre-hadronic clusters and their decays into hadrons, on the other hand, is treated by using a spatial criterion motivated by confinement and a non-perturbative model for hadronization. Finally, the cascading of produced prehadronic clusters and of hadrons includes a multitude of 2 {r_arrow} n processes, and is modeled in parallel to the parton cascade description. This paper gives a brief review of the physics underlying VNI, as well as a detailed description of the program itself. The latter program description emphasizes easy-to-use pragmatism and explains how to use the program (including simple examples), annotates input and control parameters, and discusses output data provided by it.

Hadronic interactions of the J/ψ and Adler's theorem

International Nuclear Information System (INIS)

Bourque, A.; Gale, C.; Haglin, K.L.

2004-01-01

Effective Lagrangian models of charmonium have recently been used to estimate dissociation cross sections with light hadrons. Detailed study of the symmetry properties reveals possible shortcomings relative to chiral symmetry. We therefore propose a new Lagrangian and point out distinguishing features amongst the different approaches. Moreover, we test the models against Adler's theorem, which requires, in the appropriate limit, the decoupling of pions from the theory for the normal parity sector. Using the newly proposed Lagrangian, which exhibits SU L (N f )xSU R (N f ) symmetry and complies with Adler's theorem, we find dissociation cross sections with pions that are reduced in an energy-dependent way, with respect to cases where the theorem is not fulfilled

Model of the Phase Transition Mimicking the Pasta Phase in Cold and Dense Quark-Hadron Matter

Science.gov (United States)

Ayriyan, Alexander; Grigorian, Hovik

2018-02-01

A simple mixed phase model mimicking so-called "pasta" phases in the quarkhadron phase transition is developed and applied to static neutron stars for the case of DD2 type hadronic and NJL type quark matter models. The influence of the mixed phase on the mass-radius relation of the compact stars is investigated. Model parameters are chosen such that the results are in agreement with the mass-radius constraints.

QCD as a Theory of Hadrons

Science.gov (United States)

Narison, Stephan

2007-07-01

About Stephan Narison; Outline of the book; Preface; Acknowledgements; Part I. General Introduction: 1. A short flash on particle physics; 2. The pre-QCD era; 3. The QCD story; 4. Field theory ingredients; Part II. QCD Gauge Theory: 5. Lagrangian and gauge invariance; 6. Quantization using path integral; 7. QCD and its global invariance; Part III. MS scheme for QCD and QED: Introduction; 8. Dimensional regularization; 9. The MS renormalization scheme; 10. Renormalization of operators using the background field method; 11. The renormalization group; 12. Other renormalization schemes; 13. MS scheme for QED; 14. High-precision low-energy QED tests; Part IV. Deep Inelastic Scattering at Hadron Colliders: 15. OPE for deep inelastic scattering; 16. Unpolarized lepton-hadron scattering; 17. The Altarelli-Parisi equation; 18. More on unpolarized deep inelastic scatterings; 19. Polarized deep-inelastic processes; 20. Drell-Yan process; 21. One 'prompt photon' inclusive production; Part V. Hard Processes in e+e- Collisions: Introduction; 22. One hadron inclusive production; 23. gg scatterings and the 'spin' of the photon; 24. QCD jets; 25. Total inclusive hadron productions; Part VI. Summary of QCD Tests and as Measurements; Part VII. Power Corrections in QCD: 26. Introduction; 27. The SVZ expansion; 28. Technologies for evaluating Wilson coefficients; 29. Renormalons; 30. Beyond the SVZ expansion; Part VIII. QCD Two-Point Functions: 31. References guide to original works; 32. (Pseudo)scalar correlators; 33. (Axial-)vector two-point functions; 34. Tensor-quark correlator; 35. Baryonic correlators; 36. Four-quark correlators; 37. Gluonia correlators; 38. Hybrid correlators; 39. Correlators in x-space; Part IX. QCD Non-Perturbative Methods: 40. Introduction; 41. Lattice gauge theory; 42. Chiral perturbation theory; 43. Models of the QCD effective action; 44. Heavy quark effective theory; 45. Potential approaches to quarkonia; 46. On monopole and confinement; Part X. QCD

Gluon bremsstrahlung and elastic scattering of hadrons

International Nuclear Information System (INIS)

Povh, B.

2001-01-01

The differential and the total cross sections in high energy hadron-proton interactions give a beautiful insight in the low Q 2 structure of the nucleon. The cross section is composed of two parts: a large energy independent part corresponding to the interaction of the valence quark with the target without gluon radiation and an energy dependent part caused by gluon bremsstrahlung. The gluons are located at small transverse distances of about 0.3 fm from the valence quarks. The model with two scales, the size of the hadron (R 2 ∼ 1 fm 2 ) and the size of the gluonic cloud (r 0 2 ∼ 0.1 fm 2 ), correctly predicts the total and the differential cross sections and the behaviour of diffractive dissociation in hadronic and deep inelastic events. (orig.)

Monotop phenomenology at the Large Hadron Collider

CERN Document Server

Agram, Jean-Laurent; Buttignol, Michael; Conte, Eric; Fuks, Benjamin

2014-01-01

We investigate new physics scenarios where systems comprised of a single top quark accompanied by missing transverse energy, dubbed monotops, can be produced at the LHC. Following a simplified model approach, we describe all possible monotop production modes via an effective theory and estimate the sensitivity of the LHC, assuming 20 fb$^{-1}$ of collisions at a center-of-mass energy of 8 TeV, to the observation of a monotop state. Considering both leptonic and hadronic top quark decays, we show that large fractions of the parameter space are reachable and that new physics particles with masses ranging up to 1.5 TeV can leave hints within the 2012 LHC dataset, assuming moderate new physics coupling strengths.

Aspects of hadronic structure

International Nuclear Information System (INIS)

Ferreira, P.L.

1984-01-01

An overview of the current phenomenological models of hadron structure, whose theoretical basis is the Quantum Chromodynamics (QCD), is presented. A short introduction to the QCD permits to focalize the relevant properties which are attached to those models. Following, bag-like models (in particular, MIT bag and chiral extensions) and potential-like models among them the Karl and Isgur non-relativistic model and a semi-relativistic model, free of the Klein paradox, with equal scalar-vetorial mixture of confinement potential are shortly studied. Enphasis is given to the baryons, treated, basically, as three-quarks systems. (L.C.) [pt

A quark structure of hadrons and nuclei

International Nuclear Information System (INIS)

Chakrabarty, S.; Deoghuria, S.

1992-08-01

In this review we look into the recent understanding of mesons, baryons and nuclei as few quark bound states within the framework of quantum chromodynamics (QCD). In particular, we have reviewed our understanding of the nature of confining interaction, the spin - dependence of colour forces and the role of non-perturbative effects in the study of quark forces in the potential model approach. We also give a comparative study of results obtained by several potential models with reference to the experimental data. We find that although the Lorentz nature of confinement and the nature of spin-dependent colour forces have been better understood now, only a partial understanding of these problems are obtained so far. Our study reveals that properties of baryons could be explained by the same potential model which successfully describe the mesons. However, the nuclei require chiral symmetry and non-perturbative methods for their description. We also discuss the relation between constituent, current and dynamical quark masses. We conclude that QCD motivated approaches have shown much success in explaining many results on hadronic and nuclear data. (author). 212 refs, 14 tabs

The Ways of Four-Quark Hadrons

CERN Multimedia

CERN. Geneva

2014-01-01

Ten years after the discovery of the X(3872) we can assert that a number of exotic four-quark hadrons with hidden charm and beauty have been discovered, the most recent, Z(3900), found by BES in 2013, being among the top-striking ones. However, ten years have not been enough to dispel the controversy about their inner structure, with two body hadron molecules and compact multiquark states being the withstanding antipodal models. In this seminar I will review the status of the field, presenting both the experimental facts and the theoretical pictures attempting to interpret them.

Quark-Hadron Duality in Electron Scattering

Energy Technology Data Exchange (ETDEWEB)

Wally Melnitchouk; Rolf Ent; Cynthia Keppel

2004-08-01

The duality between partonic and hadronic descriptions of physical phenomena is one of the most remarkable features of strong interaction physics. A classic example of this is in electron-nucleon scattering, in which low-energy cross sections, when averaged over appropriate energy intervals, are found to exhibit the scaling behavior expected from perturbative QCD. We present a comprehensive review of data on structure functions in the resonance region, from which the global and local aspects of duality are quantified, including its flavor, spin and nuclear medium dependence. To interpret the experimental findings, we discuss various theoretical approaches which have been developed to understand the microscopic origins of quark-hadron duality in QCD. Examples from other reactions are used to place duality in a broader context, and future experimental and theoretical challenges are identified.

Unitary screening corrections in high energy hadron reactions

Energy Technology Data Exchange (ETDEWEB)

Maor, U

1994-10-01

The role of s-channel unitarity screening corrections, calculated in the eikonal approximation, is investigated for elastic and diffractive hadron-hadron and photon-hadron scattering in the energy limit. We examine the differences between our results and those obtained from the supercritical Pomeron-Reggeon model with no such corrections. It is argued that the saturation of cross sections is attained at different scales for different channels. In particular, we point out that whereas the saturation scale for elastic scattering apparently above the Tevatron energy range, the appropriate diffraction scale is considerably lower and can be assessed with presently available data. A review of the relevant data and its implications is presented. (author). 12 refs, 3 figs, 2 tabs.

Hadron spectroscopy 1987

International Nuclear Information System (INIS)

Anon.

1987-01-01

With much particle physics research using particle beams to probe the behaviour of the quark constituents deep inside nucleons and other strongly interacting particles (hadrons), it is easy to overlook the progress being made through hadron spectroscopy – the search for and classification of rare particles – and the way it has increased our understanding of quark physics. One way of remedying this was to attend the stimulating and encouraging Hadron 87 meeting held earlier this year at the Japanese KEK Laboratory, where Jonathan Rosner from Chicago's Enrico Fermi Institute gave the concluding talk

Signatures of chiral symmetry restoration and its survival throughout the hadronic phase interactions

Directory of Open Access Journals (Sweden)

Bratkovskaya E.L.

2018-01-01

Full Text Available The effect of the chiral symmetry restoration (CSR on observables from heavy-ion collisions is studied in the energy range sNN=3–20 GeV within the Parton-Hadron-String Dynamics (PHSD transport approach. The PHSD includes the deconfinement phase transition as well as essential aspects of CSR in the dense and hot hadronic medium, which are incorporated in the Schwinger mechanism for the hadronic particle production. We adopt different parametrizations of the nuclear equation of state from the non-linear σ - ω model, which enter in the computation of the quark scalar density for the CSR mechanism, in order to estimate the uncertainty in our calculations. For the pion-nucleon ∑-term we adopt ∑π ≈ 45 MeV which corresponds to a ’world average’. Our systematic studies show that chiral symmetry restoration plays a crucial role in the description of heavy-ion collisions at sNN=3–20 GeV, realizing an increase of the hadronic particle production in the strangeness sector with respect to the non-strange one. We identify particle abundances and rapidity spectra to be suitable probes in order to extract information about CSR, while transverse mass spectra are less sensitive ones. Our results provide a microscopic explanation for the "horn" structure in the excitation function of the K+/π+ ratio: the CSR in the hadronic phase produces the steep increase of this particle ratio up to sNN ≈ 7 GeV, while the drop at higher energies is associated to the appearance of a deconfined partonic medium.

Signatures of chiral symmetry restoration and its survival throughout the hadronic phase interactions

Science.gov (United States)

Bratkovskaya, E. L.; Moreau, P.; Palmese, A.; Cassing, W.; Seifert, E.; Steinert, T.

2018-02-01

The effect of the chiral symmetry restoration (CSR) on observables from heavy-ion collisions is studied in the energy range =3-20 GeV within the Parton-Hadron-String Dynamics (PHSD) transport approach. The PHSD includes the deconfinement phase transition as well as essential aspects of CSR in the dense and hot hadronic medium, which are incorporated in the Schwinger mechanism for the hadronic particle production. We adopt different parametrizations of the nuclear equation of state from the non-linear σ - ω model, which enter in the computation of the quark scalar density for the CSR mechanism, in order to estimate the uncertainty in our calculations. For the pion-nucleon ∑-term we adopt ∑π ≈ 45 MeV which corresponds to a 'world average'. Our systematic studies show that chiral symmetry restoration plays a crucial role in the description of heavy-ion collisions at =3-20 GeV, realizing an increase of the hadronic particle production in the strangeness sector with respect to the non-strange one. We identify particle abundances and rapidity spectra to be suitable probes in order to extract information about CSR, while transverse mass spectra are less sensitive ones. Our results provide a microscopic explanation for the "horn" structure in the excitation function of the K+/π+ ratio: the CSR in the hadronic phase produces the steep increase of this particle ratio up to ≈ 7 GeV, while the drop at higher energies is associated to the appearance of a deconfined partonic medium.

Unified approach to dense matter

International Nuclear Information System (INIS)

Park, Byung-Yoon; Lee, Hee-Jung; Vento, Vicente; Kim, Joon-Il; Min, Dong-Pil; Rho, Mannque

2005-01-01

We apply the Skyrme model to dense hadronic matter, which provides a unified approach to high density, valid in the large N c limit. In our picture, dense hadronic matter is described by the classical soliton configuration with minimum energy for the given baryon number density. By incorporating the meson fluctuations on such ground state we obtain an effective Lagrangian for meson dynamics in a dense medium. Our starting point has been the Skyrme model defined in terms of pions, thereafter we have extended and improved the model by incorporating other degrees of freedom such as dilaton, kaons and vector mesons

Academic Training Lecture: Higgs Boson Searches at Hadron Colliders

CERN Multimedia

HR Department

2010-01-01

Regular Programme 21, 22, 23 & 24 June 2010 from 11:00 to 12:00 - Main Auditorium, Bldg. 500-1-001 Higgs Boson Searches at Hadron Colliders by Dr. Karl Jakobs (University of Freiburg) In these Academic Training lectures, the phenomenology of Higgs bosons and search strategies at hadron colliders are discussed. After a brief introduction on Higgs bosons in the Standard Model and a discussion of present direct and indirect constraints on its mass the status of the theoretical cross section calculations for Higgs boson production at hadron colliders is reviewed. In the following lectures important experimental issues relevant for Higgs boson searches (trigger, measurements of leptons, jets and missing transverse energy) are presented. This is followed by a detailed discussion of the discovery potential for the Standard Model Higgs boson for both the Tevatron and the LHC experiments. In addition, various scenarios beyond the Standard Model, primarily the MSSM, are considered. Finally, the potential and ...

R&D; studies on the hadronic calorimeter and physics simulations on the Standard Model and minimal supersymmetric Standard Model Higgs bosons in the CMS experiment

CERN Document Server

Duru, Firdevs

2007-01-01

This thesis consists of two main parts: R&D; studies done on the Compact Muon Solenoid (CMS) Hadronic Calorimeter (HCAL) and physics simulations on the Higgs boson for a Minimal Supersymmetric Standard Model (MSSM) and a Standard Model (SM) channel. In the first part, the air core light guides used in the read-out system of the Hadronic Forward (HF) calorimeter and the reflective materials used in them are studied. Then, tests and simulations were performed to find the most efficient way to collect Cerenkov light from the quartz plates, which are proposed as a substitute for the scintillator tiles in the Hadronic Endcap (HE) calorimeter due to radiation damage problems. In the second part physics simulations and their results are presented. The MSSM channel H/A[arrow right]ττ [arrow right]l l v v v v is studied to investigate the jet and missing transverse energy (MET) reconstruction of the CMS detector. The effects of the jet and MET corrections on the Higgs boson mass reconstruction are investigated. ...

Behavior of the hadron potential at large distances and properties of the hadron spin-flip amplitude

International Nuclear Information System (INIS)

Predazzi, E.; Selyugin, O.V.

2002-01-01

The impact of the form of the hadron potential at large distances on the behavior of the hadron spin-flip amplitude at small angles is examined. The t-dependence of the spin-flip amplitude of high-energy hadron elastic scattering is analyzed under different assumptions on the hadron interaction. It is shown that the long tail of the nonGaussian form of the hadron potential of the hadron interaction in the impact parameter representation leads to a large value of the slope of the spin-flip amplitude (without the kinematical factor √(vertical stroke t vertical stroke)) as compared with the slope of the spin-nonflip amplitude. This effect can explain the form of the differential cross-section and the analyzing power at small transfer momenta. The methods for the definition of the spin-dependent part of the hadron scattering amplitude are presented. A possibility to investigate the structure of the hadron spin-flip amplitude from the accurate measure of the differential cross-section and the spin correlation parameters is shown. (orig.)

Hadron production at LHC in dipole momentum space

Energy Technology Data Exchange (ETDEWEB)

Basso, E. A.; Gay Ducati, M. B. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970 - Porto Alegre, RS (Brazil); De Oliveira, E. G. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05314-970 Sao Paulo, SP (Brazil)

2013-03-25

The dipole color approach is the framework that considers the quark-antiquark pair scattering off the target. The rapidity evolution of color dipoles is given by the nonlinear Balitsky-Kovchegov (BK) equation, for which analytical solutions are not yet known. A good way to explore the asymptotic BK solutions is through the traveling wave method of QCD, that uses a correspondence between the BK evolution equation in momentum space and reaction-diffusion physics. Using the traveling wave based AGBS model for the dipole amplitude in momentum space, and within the k{sub t}-factorization formalism, we describe the LHC data on single inclusive hadron yield for p-p collisions.

Hadron production at LHC in dipole momentum space

International Nuclear Information System (INIS)

Basso, E. A.; Gay Ducati, M. B.; De Oliveira, E. G.

2013-01-01

The dipole color approach is the framework that considers the quark-antiquark pair scattering off the target. The rapidity evolution of color dipoles is given by the nonlinear Balitsky-Kovchegov (BK) equation, for which analytical solutions are not yet known. A good way to explore the asymptotic BK solutions is through the traveling wave method of QCD, that uses a correspondence between the BK evolution equation in momentum space and reaction-diffusion physics. Using the traveling wave based AGBS model for the dipole amplitude in momentum space, and within the k t -factorization formalism, we describe the LHC data on single inclusive hadron yield for p–p collisions.

Masses of the light hadrons in the chiral and cloudy bag models

International Nuclear Information System (INIS)

Saito, Koichi.

1983-10-01

The masses of the light hadrons except for the pion are calculated in the stable chiral and cloudy bag models with the massless or massive u, d quark and pion. Two difficulties in these models, i.e. the lack of stability and the divergence of the quark self-energy, are removed by taking account of a simple non-local quark-pion interaction. The effects of the finite size of the qq-bar pion and the behavior of the quark self-energy are discussed in detail. In our calculation the bag self-energy due to the pion has an important role in the origin of the N-Δ and the Σ-Λ mass differences. The baryon octet and decuplet masses are well reproduced by the present model. (author)

Hadron Therapy for Cancer Treatment

International Nuclear Information System (INIS)

Lennox, Arlene

2003-01-01

The biological and physical rationale for hadron therapy is well understood by the research community, but hadron therapy is not well established in mainstream medicine. This talk will describe the biological advantage of neutron therapy and the dose distribution advantage of proton therapy, followed by a discussion of the challenges to be met before hadron therapy can play a significant role in treating cancer. A proposal for a new research-oriented hadron clinic will be presented.

Study of the hadron shower profiles with the ATLAS tile hadron calorimeter

International Nuclear Information System (INIS)

Budagov, Yu.A.; Rusakovich, N.A.; Vinogradov, V.B.; Kul'chitskij, Yu.A.; Rumyantsev, V.S.; Nessi, M.

1997-01-01

The lateral and longitudinal profiles of the hadronic showers detected by ATLAS iron-scintillator tile hadron calorimeter with longitudinal tile configuration have been investigated. The results are based on 100 GeV pion beam data. Due to the beam scan provided many different beam impact locations with cells it is succeeded to obtain detailed picture of transverse shower behavior. The underlying radial energy densities for four depths and for overall calorimeter have been reconstructed. The three-dimensional hadronic shower parametrization has been suggested

Hadron multiplicities at COMPASS

Energy Technology Data Exchange (ETDEWEB)

Du Fresne von Hohenesche, Nicolas [Institut fuer Kernphysik, Universitaet Mainz, Johann-Joachim-Becher-Weg 45, 55128 Mainz (Germany); Collaboration: COMPASS Collaboration

2014-07-01

Quark fragmentation functions (FF) D{sub q}{sup h}(z,Q{sup 2}) describe final-state hadronization of quarks q into hadrons h. The FFs can be extracted from hadron multiplicities produced in semi-inclusive deep inelastic scattering. The COMPASS collaboration has recently measured charged hadron multiplicities for identified pions and kaons using a 160 GeV/c muon beam impinging on an iso-scalar target. The data cover a large kinematical range and provide an important input for global QCD analyses of world data at NLO, aiming at the determination of FFs in particular in the strange quark sector. The newest results from COMPASS on pion and kaon multiplicities will be presented.

Light ions radiobiological effects on human tumoral cells: measurements modelling and application to hadron-therapy

International Nuclear Information System (INIS)

Jalade, P.

2005-11-01

In classical radiotherapy, the characteristics of photons interactions undergo limits for the treatment of radioresistant and not well located tumours. Pioneering treatments of patients at the Lawrence Laboratory at Berkeley has demonstrated two advantages of hadrons beams: the Relative Biologic Effect (the RBE) and the ballistic of the beams. Since 1994, the clinical centre at Chiba, has demonstrated successfully the applicability of the method. A physics group, managed by G. Kraft, at Darmstadt in Germany, has underlined the advantages of carbon beams. An European pool, called ENGIGHT (European Network for LIGHt ion Therapy) has been created in which the French ETOILE project appeared. The purpose of the thesis concerns measurements and models of 'in vitro' human cells survival. In the first part, the nowadays situation in particles interactions, tracks and cells structures and radiobiology is presented here. The second is devoted to the models based on the beam tracks and localization of the physical dose. Discussion of sensitivity to various parameters of the model has been realized with the help of numerical simulations. Finally the predictions of the improved model has been compared to experimental irradiations of human cells with argon and carbon beams of the GANIL machine. Conclusion of such study shows the performance and limits of a local model for predicting the radiobiological efficiency of light ions in hadron-therapy. (author)

Hadron Physics at FAIR

International Nuclear Information System (INIS)

Wiedner, Ulrich

2011-01-01

The new FAIR facility in Darmstadt has a broad program in the field of hadron and nuclear physics utilizing ion beams with unprecedented intensity and accuracy. The hadron physics program centers around the the high-energy storage ring HESR for antiprotons and the PANDA experiment that is integrated in it. The physics program includes among others topics like hadron spectroscopy in the charmonium mass region and below, hyperon physics, electromagnetic processes and charm in nuclei.

Experimental tests of QCD: Deep inelastic scattering, e+e- annihilation and hard hadron-hadron scattering

International Nuclear Information System (INIS)

Hansl-Kozanecka, T.

1992-01-01

In this set of lectures the author examines phenomenological aspects of quantum chromodynamics (QCD) which are relevant for lepton-hadron, electron-positron, and hadron-hadron collisions. He points how the strength of the strong coupling constant, αs, makes QCD calculations converge much more slowly in powers of αs, and missing higher order terms must be carefully estimated. The most stringent test of QCD can be performed in deep inelastic lepton scattering and in e + e - annihilation. In deep inelastic scattering the virtual γ or W/Z are used as a probe of the nucleon structure. They couple to quarks, not gluons. Only the incoming and outgoing lepton have to be measured. The hadronic fluid state does not have to be analyzed. In e + e - annihilation the virtual γ or Z 0 decays to lepton and quark pairs. The branching ratio into quarks is a counter for the number of colours available, the detailed structure of the final state reflects the radiation of gluons as the initial quark-antiquark separate from each other. Quarks and gluons are observed here, though in the presence of hadron formation. Hard hadron-hadron, or parton-parton collisions provide cross sections dominated by the gluon component, which is only weakly measured in deep inelastic collisions. Recent experimental results in these three areas are reviewed, and compared to QCD calculations. Scaling violations and analysis of structure functions in deep inelastic scattering are reviewed. QCD in e + e - branching to hadrons is reviewed near the Z 0 resonance, and a number of cross sections and jet related properties which can be calculated as a function of the single parameter αs are reviewed. Hadron-hadron collisions are reviewed for three processes; jet production, direct photon production, and high p perpendicular W/Z boson production

The d-bar - u-bar asymmetry of the proton in a pion cloud model approach

International Nuclear Information System (INIS)

Magnin, J.; Christiansen, H.R.

1999-03-01

We study the d-bar - u-bar asymmetry of the proton in a model approach in which hadronic fluctuations of the nucleon are generated through gluon splitting and recombination mechanisms. Within this framework, it is shown that the d -u asymmetry of the proton is consistently described by including only nucleon fluctuations to |πN> and |πΔ> bound states. Predictions of the model closely agree with the recent experimental data of the E-866/Nu Sea Collaboration. (author)

Dynamics of chemical equilibrium of hadronic matter close to Tc

International Nuclear Information System (INIS)

Noronha-Hostler, J.; Beitel, M.; Greiner, C.; Shovkovy, I.

2010-01-01

Quick chemical equilibration times of hadrons (specifically, pp-bar, KK-bar, ΛΛ-bar, and ΩΩ-bar pairs) within a hadron gas are explained dynamically using Hagedorn states, which drive particles into equilibrium close to the critical temperature. Within this scheme, we use master equations and derive various analytical estimates for the chemical equilibration times. We compare our model to recent lattice results and find that for both T c =176 MeV and T c =196 MeV, the hadrons can reach chemical equilibrium almost immediately, well before the chemical freeze-out temperatures found in thermal fits for a hadron gas without Hagedorn states. Furthermore, the ratios p/π, K/π, Λ/π, and Ω/π match experimental values well in our dynamical scenario.

A conceptual solution for a beam halo collimation system for the Future Circular hadron-hadron Collider (FCC-hh)

Science.gov (United States)

Fiascaris, M.; Bruce, R.; Redaelli, S.

2018-06-01

We present the first conceptual solution for a collimation system for the hadron-hadron option of the Future Circular Collider (FCC-hh). The collimation layout is based on the scaling of the present Large Hadron Collider collimation system to the FCC-hh energy and it includes betatron and momentum cleaning, as well as dump protection collimators and collimators in the experimental insertions for protection of the final focus triplet magnets. An aperture model for the FCC-hh is defined and the geometrical acceptance is calculated at injection and collision energy taking into account mechanical and optics imperfections. The performance of the system is then assessed through the analysis of normalized halo distributions and complete loss maps for an ideal lattice. The performance limitations are discussed and a solution to improve the system performance with the addition of dispersion suppression collimators around the betatron cleaning insertion is presented.

An estimate of the bulk viscosity of the hadronic medium

Science.gov (United States)

Sarwar, Golam; Chatterjee, Sandeep; Alam, Jane

2017-05-01

The bulk viscosity (ζ) of the hadronic medium has been estimated within the ambit of the Hadron Resonance Gas (HRG) model including the Hagedorn density of states. The HRG thermodynamics within a grand canonical ensemble provides the mean hadron number as well as its fluctuation. The fluctuation in the chemical composition of the hadronic medium in the grand canonical ensemble can result in non-zero divergence of the hadronic fluid flow velocity, allowing us to estimate the ζ of the hadronic matter up to a relaxation time. We study the influence of the hadronic spectrum on ζ and find its correlation with the conformal symmetry breaking measure, ε -3P. We estimate ζ along the contours with constant, S/{N}B (total entropy/net baryon number) in the T-μ plane (temperature-baryonic chemical potential) for S/{N}B=30,45 and 300. We also assess the value of ζ on the chemical freeze-out curve for various centers of mass energy (\\sqrt{{s}{NN}}) and find that the bulk viscosity to entropy density ratio, \\zeta /s is larger in the energy range of the beam energy scan program of RHIC, low energy SPS run, AGS, NICA and FAIR, than LHC energies.

Simulation of soft hadron hadron collisions at ultrarelativistic energies

International Nuclear Information System (INIS)

Werner, K.

1987-01-01

An event generator to simulate ultrarelativistic hadron hadron collisions is proposed. It is based on the following main assumptions: the process can be divided into two independent steps, string formation and string fragmentation; strings are formed as a consequence of color exchange between a quark of the projectile and a quark of the target; the fragmentation of strings is the same as in e + e - annihilation or in lepton nucleon scattering. 11 refs., 4 figs

Rapidity distributions of hadrons in the HydHSD hybrid model

Energy Technology Data Exchange (ETDEWEB)

Khvorostukhin, A. S., E-mail: hvorost@theor.jinr.ru; Toneev, V. D. [Joint Institute for Nuclear Research (Russian Federation)

2017-03-15

A multistage hybrid model intended for describing heavy-ion interactions in the energy region of the NICA collider under construction in Dubna is proposed. The model combines the initial, fast, interaction stage described by the model of hadron string dynamics (HSD) and the subsequent evolution that the expanding system formed at the first stage experiences at the second stage and which one treats on the basis of ideal hydrodynamics; after the completion of the second stage, the particles involved may still undergo rescattering (third interaction stage). The model admits three freeze-out scenarios: isochronous, isothermal, and isoenergetic. Generally, the HydHSD hybrid model developed in the present study provides fairly good agreement with available experimental data on proton rapidity spectra. It is shown that, within this hybrid model, the two-humped structure of proton rapidity distributions can be obtained either by increasing the freeze-out temperature and energy density or by more lately going over to the hydrodynamic stage. Although the proposed hybrid model reproduces rapidity spectra of protons, it is unable to describe rapidity distributions of pions, systematically underestimating their yield. It is necessary to refine the model by including viscosity effects at the hydrodynamic stage of evolution of the system and by considering in more detail the third interaction stage.

Hadron--hadron reactions, high multiplicity

International Nuclear Information System (INIS)

Diebold, R.

1978-09-01

A coverage of results on high energy and high multiplicity hadron reactions, charm searches and related topics, ultrahigh energy events and exotic phenomena (cosmic rays), and the nuclear effects in high energy collisions and related topics is discussed. 67 references

Hadronic light-by-light scattering contribution to the muon g - 2 on the lattice

Science.gov (United States)

Asmussen, Nils; Gérardin, Antoine; Green, Jeremy; Gryniuk, Oleksii; von Hippel, Georg; Meyer, Harvey B.; Nyffeler, Andreas; Pascalutsa, Vladimir; Wittig, Hartmut

2018-05-01

We briefly review several activities at Mainz related to hadronic light-by-light scattering (HLbL) using lattice QCD. First we present a position-space approach to the HLbL contribution in the muon g̅2, where we focus on exploratory studies of the pion-pole contribution in a simple model and the lepton loop in QED in the continuum and in infinite volume. The second part describes a lattice calculation of the double-virtual pion transition form factor Fπ0γ*γ* (q21; q21) in the spacelike region with photon virtualities up to 1.5 GeV2 which paves the way for a lattice calculation of the pion-pole contribution to HLbL. The third topic involves HLbL forward scattering amplitudes calculated in lattice QCD which can be described, using dispersion relations (HLbL sum rules), by γ*γ* → hadrons fusion cross sections and then compared with phenomenological models.

Temperature anomalies of shock and isentropic waves of quark-hadron phase transition

Science.gov (United States)

Konyukhov, A. V.; Iosilevskiy, I. L.; Levashov, P. R.; Likhachev, A. P.

2018-01-01

In this work, we consider a phenomenological equation of state, which combinesstatistical description for hadron gas and a bag-model-based approach for the quark-gluon plasma. The equation of state is based on the excluded volume method in its thermodynamically consistent variant from Satarov et al [2009 Phys. At. Nucl. 72 1390]. The characteristic shape of the Taub adiabats and isentropes in the phase diagram is affected by the anomalous pressure-temperature dependence along the curve of phase equilibrium. The adiabats have kink points at the boundary of the two-phase region, inside which the temperature decreases with compression. Thermodynamic properties of matter observed in the quark-hadron phase transition region lead to hydrodynamic anomalies (in particular, to the appearance of composite compression and rarefaction waves). On the basis of relativistic hydrodynamics equations we investigate and discuss the structure and anomalous temperature behavior in these waves.

Azimuthal coil size and field quality in the main CERN Large Hadron Collider dipoles

Directory of Open Access Journals (Sweden)

P. Ferracin

2002-06-01

Full Text Available Field quality in superconducting magnets strongly depends on the geometry of the coil. Fiberglass spacers (shims placed between the coil and the collars have been used to optimize magnetic and mechanical performances of superconducting magnets in large accelerators. A change in the shim thickness affects both the geometry of the coil and its state of compression (prestress under operational conditions. In this paper we develop a coupled magnetomechanical model of the main Large Hadron Collider dipole. This model allows us to evaluate the prestress dependence on the shim thickness and the map of deformations of the coil and the collars. Results of the model are compared to experimental measurements carried out in a dedicated experiment, where a magnet model has been reassembled 5 times with different shims. A good agreement is found between simulations and experimental data both on the mechanical behavior and on the field quality. We show that this approach allows us to improve this agreement with respect to models previously used in the literature. We finally evaluate the range of tunability that will be provided by shims during the production of the Large Hadron Collider main dipoles.

Hadron Dragons strike again

CERN Multimedia

2009-01-01

The CERN Dragon Boat team – the Hadron Dragons – achieved a fantastic result at the "Paddle for Cancer" Dragon Boat Festival at Lac de Joux on 6 September. CERN Hadron Dragons heading for the start line.Under blue skies and on a clear lake, the Hadron Dragons won 2nd place in a hard-fought final, following top times in the previous heats. In a close and dramatic race – neck-and-neck until the final 50 metres – the local Lac-de-Joux team managed to inch ahead at the last moment. The Hadron Dragons were delighted to take part in this festival. No one would turn down a day out in such a friendly and fun atmosphere, but the Dragons were also giving their support to cancer awareness and fund-raising in association with ESCA (English-Speaking Cancer Association of Geneva). Riding on their great success in recent competitions, the Hadron Dragons plan to enter the last Dragon Boat festival of 2009 in Annecy on 17-18 October. This will coincide with t...

Large degeneracy of excited hadrons and quark models

International Nuclear Information System (INIS)

Bicudo, P.

2007-01-01

The pattern of a large approximate degeneracy of the excited hadron spectra (larger than the chiral restoration degeneracy) is present in the recent experimental report of Bugg. Here we try to model this degeneracy with state of the art quark models. We review how the Coulomb Gauge chiral invariant and confining Bethe-Salpeter equation simplifies in the case of very excited quark-antiquark mesons, including angular or radial excitations, to a Salpeter equation with an ultrarelativistic kinetic energy with the spin-independent part of the potential. The resulting meson spectrum is solved, and the excited chiral restoration is recovered, for all mesons with J>0. Applying the ultrarelativistic simplification to a linear equal-time potential, linear Regge trajectories are obtained, for both angular and radial excitations. The spectrum is also compared with the semiclassical Bohr-Sommerfeld quantization relation. However, the excited angular and radial spectra do not coincide exactly. We then search, with the classical Bertrand theorem, for central potentials producing always classical closed orbits with the ultrarelativistic kinetic energy. We find that no such potential exists, and this implies that no exact larger degeneracy can be obtained in our equal-time framework, with a single principal quantum number comparable to the nonrelativistic Coulomb or harmonic oscillator potentials. Nevertheless we find it plausible that the large experimental approximate degeneracy will be modeled in the future by quark models beyond the present state of the art

The surface between QCD and Hadron physics

International Nuclear Information System (INIS)

Von Geramb, H.V.; Bayansan, D.

2005-01-01

The relativistic potential concept is fostered for the description of nucleon-nucleon (NN) interaction and scattering for energies 0 < T Lab ≤ 3 GeV. We use a formalism, developed by Crater and Van Alstine, for two coupled spin 1/2 particles in terms of coupled Dirac equations with constraint instant form dynamics. Sets of coupled Dirac equations are used and reduced into partial wave Schr¨odinger type equations. We study np and pp scattering phase shifts for energies 0 to 3 GeV and the deuteron bound state. The interactions are inspired and parameterized in terms of π, η, ρ, ω and σ meson exchanges for which we adjust coupling constants. This yields, in the first instant, high quality fits to the Arndt phase shifts 0 to 300 MeV. Second, the potentials show a universal, independent from angular momentum, core potential which is generated with the relativistic meson exchange dynamics. Extrapolations towards higher energies, up to T Lab equal 3 GeV, allow to separate a QCD dominated short range zone as well as inelastic nucleon excitation mechanism contributing to meson production. A local short range optical model, replacing the short range meson exchange Dirac potential, produces exact agreement between theoretical and phase shifts data. The optical model potentials reflect short lived complex multi hadronic intermediate structure formation of which the optical model parameters give a consistent picture. This phenomenological approach shows the need to describe the short range NN interaction zone r < 0.8 fm with a microscopic model. It implies using the quark content of the nucleons and gluon exchange as well as the need for a microscopic description of intermediate Δ and hadron pair excitations. The conventional soft or hard core NN potentials remain valid for an effective short range low energy description

Scaling of multiplicity distribution in hadron collisions and diffractive-excitation like models

International Nuclear Information System (INIS)

Buras, A.J.; Dethlefsen, J.M.; Koba, Z.

1974-01-01

Multiplicity distribution of secondary particles in inelastic hadron collision at high energy is studied in the semiclassical impact parameter representation. The scaling function is shown to consist of two factors: one geometrical and the other dynamical. We propose a specific choice of these factors, which describe satisfactorily the elastic scattering, the ratio of elastic to total cross-section and the simple scaling behaviour of multiplicity distribution in p-p collisions. Two versions of diffractive-excitation like models (global and local excitation) are presented as interpretation of our choice of dynamical factor. (author)

Inclusive spectra of hadrons in proton-nucleus collisions

International Nuclear Information System (INIS)

Gevorkyan, S.R.; Gulkanyan, G.R.; Kotzinyan, A.M.; Zhamkochyan, V.M.

1985-01-01

A model is proposed, which allows one to describe all exprimental data on inclusive spectra of different hadrons produced on nuclei. The model is based on the following assumptions. After the first inelastic collision with nucleon in the nucleus the proton transforms into some excited system H, which collides with the other nucleons during its passage through the nucleus. Since in inelastic collisions the slow sea partons play the dominant role, the valence quarks of this system H coincide with those of proton. Fragmentation of H into hadrons (as well as into proton) is dilated in the lab system by the Lorentz factor E/m >> 1 and so it takes place out of the nucleus. Using the methods of multiple scattering theory one can receive the connection between inclusive spectra on nuclei and those on nucleons. The calculations of inclusive spectra of different hadrons (p, p, πsup(-+), ksup(+-)) were done, and a satisfactory description of the experimental data was obtained. It should be noted that this description was done without introduction of any free parameters. Analogous models are discussed, and their diffference from the method proposed is outlined

Searches for Natural Supersymmetry in Hadronic Final States with Heavy Flavor at ATLAS

CERN Document Server

Butler, Bart

This thesis presents the hadronic-channel supersymmetric searches for direct sbottom and gluino-mediated sbottom and stop production performed on 4.71 fb$^{-1}$ of $\\sqrt{s}$ = 7 TeV data collected by the ATLAS detector at the Large Hadron Collider. These signatures are characterized by final states with multiple b-tagged jets and missing transverse energy, and the analysis strategy is chosen accordingly. Particular emphasis is placed on the utilization of the simplified models approach in signal characterization, optimization, and interpretation of results. No significant excess is observed resulting in limits set at 95% confidence level. Relative to the previous versions of the analyses, this iteration represents a several-fold increase in sensitivity to the new physics signatures considered. This is largely due to the use of three b-tag signal regions as well as signal regions based on initial state radiation.

Test of colour reconnection models using three-jet events in hadronic Z decays

International Nuclear Information System (INIS)

Schael, S.; Barate, R.; Bruneliere, R.; De Bonis, I.; Decamp, D.; Goy, C.; Jezequel, S.; Lees, J.-P.; Martin, F.; Merle, E.; Minard, M.-N.; Pietrzyk, B.; Trocme, B.; Bravo, S.; Casado, M.P.; Chmeissani, M.; Crespo, J.M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, L.; Martinez, M.; Pacheco, A.; Ruiz, H.; Colaleo, A.; Creanza, D.; De Filippis, N.; de Palma, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Barklow, T.; Buchmueller, O.; Cattaneo, M.; Clerbaux, B.; Drevermann, H.; Forty, R.W.; Frank, M.; Gianotti, F.; Hansen, J.B.; Harvey, J.; Hutchcroft, D.E.; Janot, P.; Jost, B.; Kado, M.; Mato, P.; Moutoussi, A.; Ranjard, F.; Rolandi, L.; Schlatter, D.; Teubert, F.; Valassi, A.; Videau, I.; Badaud, F.; Dessagne, S.; Falvard, A.; Fayolle, D.; Gay, P.; Jousset, J.; Michel, B.; Monteil, S.; Pallin, D.; Pascolo, J.M.; Perret, P.; Hansen, J.D.; Hansen, J.R.; Hansen, P.H.; Kraan, A.C.; Nilsson, B.S.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Brient, J.-C.; Machefert, F.; Rouge, A.; Videau, H.; Ciulli, V.; Focardi, E.; Parrini, G.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bossi, F.; Capon, G.; Cerutti, F.; Chiarella, V.; Laurelli, P.; Mannocchi, G.; Murtas, G.P.; Passalacqua, L.; Kennedy, J.; Lynch, J.G.; Negus, P.; O'Shea, V.; Thompson, A.S.; Wasserbaech, S.; Cavanaugh, R.; Dhamotharan, S.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E.E.; Putzer, A.; Stenzel, H.; Tittel, K.; Wunsch, M.; Beuselinck, R.; Cameron, W.; Davies, G.; Dornan, P.J.; Girone, M.; Marinelli, N.; Nowell, J.; Rutherford, S.A.; Sedgbeer, J.K.; Thompson, J.C.; White, R.; Ghete, V.M.; Girtler, P.; Jussel, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bouhova-Thacker, E.; Bowdery, C.K.; Clarke, D.P.; Ellis, G.; Finch, A.J.; Foster, F.; Hughes, G.; Jones, R.W.L.; Pearson, M.R.; Robertson, N.A.; Smizanska, M.; van der Aa, O.; Delaere, C.; Leibenguth, G.; Lemaitre, V.; Blumenschein, U.; Hoelldorfer, F.; Jakobs, K.; Kayser, F.; Mueller, A.-S.; Renk, B.; Sander, H.-G.; Schmeling, S.; Wachsmuth, H.; Zeitnitz, C.; Ziegler, T.; Bonissent, A.; Coyle, P.; Curtil, C.; Ealet, A.; Fouchez, D.; Payre, P.; Tilquin, A.; Ragusa, F.; David, A.; Dietl, H.; Ganis, G.; Huettmann, K.; Luetjens, G.; Maenner, W.; Moser, H.-G.; Settles, R.; Villegas, M.; Wolf, G.; Boucrot, J.; Callot, O.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, P.; Jacholkowska, A.; Serin, L.; Veillet, J.-J.; Azzurri, P.; Bagliesi, G.; Boccali, T.; Foa, L.; Giammanco, A.; Giassi, A.; Ligabue, F.; Messineo, A.; Palla, F.; Sanguinetti, G.; Sciaba, A.; Sguazzoni, G.; Spagnolo, P.; Tenchini, R.; Venturi, A.; Verdini, P.G.; Awunor, O.; Blair, G.A.; Cowan, G.; Garcia-Bellido, A.; Green, M.G.; Medcalf, T.; Misiejuk, A.; Strong, J.A.; Teixeira-Dias, P.; Clifft, R.W.; Edgecock, T.R.; Norton, P.R.; Tomalin, I.R.; Ward, J.J.; Bloch-Devaux, B.; Boumediene, D.; Colas, P.; Fabbro, B.; Lancon, E.; Lemaire, M.-C.; Locci, E.; Perez, P.; Rander, J.; Tuchming, B.; Vallage, B.; Litke, A.M.; Taylor, G.; Booth, C.N.; Cartwright, S.; Combley, F.; Hodgson, P.N.; Lehto, M.; Thompson, L.F.; Boehrer, A.; Brandt, S.; Grupen, C.; Hess, J.; Ngac, A.; Prange, G.; Borean, C.; Giannini, G.; He, H.; Putz, J.; Rothberg, J.; Armstrong, S.R.; Berkelman, K.; Cranmer, K.; Ferguson, D.P.S.; Gao, Y.; Gonzalez, S.; Hayes, O.J.; Hu, H.; Jin, S.; Kile, J.; McNamara III, P.A.; Nielsen, J.; Pan, Y.B.; von Wimmersperg-Toeller, J.H.; Wiedenmann, W.; Wu, J.; Wu, S.L.; Wu, X.; Zobernig, G.

2006-01-01

Hadronic Z decays into three jets are used to test QCD models of colour reconnection (CR). A sensitive quantity is the rate of gluon jets with a gap in the particle rapidity distribution and zero jet charge. Gluon jets are identified by either energy-ordering or by tagging two b-jets. The rates predicted by two string-based tunable CR models, one implemented in JETSET (the GAL model), the other in ARIADNE, are too high and disfavoured by the data, whereas the rates from the corresponding non-CR standard versions of these generators are too low. The data can be described by the GAL model assuming a small value for the R 0 parameter in the range 0.01-0.02. (orig.)

Test of Colour Reconnection Models using Three-Jet Events in Hadronic Z Decays

CERN Document Server

Schael, S; Brunelière, R; De Bonis, I; Décamp, D; Goy, C; Jézéquel, S; Lees, J P; Martin, F; Merle, E; Minard, M N; Pietrzyk, B; Trocmé, B; Bravo, S; Casado, M P; Chmeissani, M; Crespo, J M; Fernández, E; Fernández-Bosman, M; Garrido, L; Martínez, M; Pacheco, A; Ruiz, H; Colaleo, A; Creanza, D; De Filippis, N; De Palma, M; Iaselli, G; Maggi, G; Maggi, M; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Tricomi, A; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Abbaneo, D; Barklow, T; Buchmüller, O L; Cattaneo, M; Clerbaux, B; Drevermann, H; Forty, R W; Frank, M; Gianotti, F; Hansen, J B; Harvey, J; Hutchcroft, D E; Janot, P; Jost, B; Kado, M; Mato, P; Moutoussi, A; Ranjard, F; Rolandi, Luigi; Schlatter, W D; Teubert, F; Valassi, A; Videau, I; Badaud, F; Dessagne, S; Falvard, A; Fayolle, D; Gay, P; Jousset, J; Michel, B; Monteil, S; Pallin, D; Pascolo, J M; Perret, P; Hansen, J D; Hansen, J R; Hansen, P H; Kraan, A C; Nilsson, B S; Kyriakis, A; Markou, C; Simopoulou, E; Vayaki, A; Zachariadou, K; Blondel, A; Brient, J C; Machefert, F; Rougé, A; Videau, H L; Ciulli, V; Focardi, E; Parrini, G; Antonelli, A; Antonelli, M; Bencivenni, G; Bossi, F; Capon, G; Cerutti, F; Chiarella, V; Laurelli, P; Mannocchi, G; Murtas, G P; Passalacqua, L; Kennedy, J; Lynch, J G; Negus, P; O'Shea, V; Thompson, A S; Wasserbaech, S; Cavanaugh, R J; Dhamotharan, S; Geweniger, C; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Stenzel, H; Tittel, K; Wunsch, M; Beuselinck, R; Cameron, W; Davies, G; Dornan, P J; Girone, M; Marinelli, N; Nowell, J; Rutherford, S A; Sedgbeer, J K; Thompson, J C; White, R; Ghete, V M; Girtler, P; Kneringer, E; Kuhn, D; Rudolph, G; Bouhova-Thacker, E; Bowdery, C K; Clarke, D P; Ellis, G; Finch, A J; Foster, F; Hughes, G; Jones, R W L; Pearson, M R; Robertson, N A; Smizanska, M; van der Aa, O; Delaere, C; Leibenguth, G; Lemaître, V; Blumenschein, U; Hölldorfer, F; Jakobs, K; Kayser, F; Müller, A S; Renk, B; Sander, H G; Schmeling, S; Wachsmuth, H W; Zeitnitz, C; Ziegler, T; Bonissent, A; Coyle, P; Curtil, C; Ealet, A; Fouchez, D; Payre, P; Tilquin, A; Ragusa, F; David, A; Dietl, H; Ganis, G; Hüttmann, K; Lütjens, G; Männer, W; Moser, H G; Settles, R; Villegas, M; Wolf, G; Boucrot, J; Callot, O; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacholkowska, A; Serin, L; Veillet, J J; Azzurri, P; Bagliesi, G; Boccali, T; Foà, L; Giammanco, A; Giassi, A; Ligabue, F; Messineo, A; Palla, F; Sanguinetti, G; Sciabà, A; Sguazzoni, G; Spagnolo, P; Tenchini, R; Venturi, A; Verdini, P G; Awunor, O; Blair, G A; Cowan, G; García-Bellido, A; Green, M G; Medcalf, T; Misiejuk, A; Strong, J A; Teixeira-Dias, P; Clifft, R W; Edgecock, T R; Norton, P R; Tomalin, I R; Ward, J J; Bloch-Devaux, B; Boumediene, D E; Colas, P; Fabbro, B; Lançon, E; Lemaire, M C; Locci, E; Pérez, P; Rander, J; Tuchming, B; Vallage, B; Litke, A M; Taylor, G; Booth, C N; Cartwright, S; Combley, F; Hodgson, P N; Lehto, M H; Thompson, L F; Böhrer, A; Brandt, S; Grupen, C; Hess, J; Ngac, A; Prange, G; Borean, C; Giannini, G; He, H; Pütz, J; Rothberg, J E; Armstrong, S R; Berkelman, K; Cranmer, K; Ferguson, D P S; Gao, Y; González, S; Hayes, O J; Hu, H; Jin, S; Kile, J; McNamara, P A; Nielsen, J; Pan, Y B; Von Wimmersperg-Töller, J H; Wiedenmann, W; Wu, J; Wu, S L; Wu, X; Zobernig, G; Dissertori, G

2006-01-01

Hadronic Z decays into three jets are used to test QCD models of colour reconnection (CR). A sensitive quantity is the rate of gluon jets with a gap in the particle rapidity distribution and zero jet charge. Gluon jets are identified by either energy-ordering or by tagging two b-jets. The rates predicted by two string-based tunable CR models, one implemented in JETSET (the GAL model), the other in ARIADNE, are too high and disfavoured by the data, whereas the rates from the corresponding non-CR standard versions of these generators are too low. The data can be described by the GAL model assuming a small value for the R_0 parameter in the range 0.01-0.02.

Relevance of the hadronic interaction model in the interpretation of multiple muon data as detected with the MACRO experiment

International Nuclear Information System (INIS)

Ambrosio, M.; Antolini, R.; Aramo, C.; Auriemma, G.; Baldini, A.; Barbarino, G. C.; Barish, B. C.; Battistoni, G.; Bellotti, R.; Bemporad, C.; Bernardini, P.; Bilokon, H.; Bisi, V.; Bloise, C.; Bower, C.; Bussino, S.; Cafagna, F.; Calicchio, M.; Campana, D.; Carboni, M.; Castellano, M.; Cecchini, S.; Cei, F.; Chiarella, V.; Coutu, S.; De Benedictis, L.; De Cataldo, G.; Dekhissi, H.; De Marzo, C.; De Mitri, I.; De Vincenzi, M.; Di Credico, A.; Erriquez, O.; Favuzzi, C.; Forti, C.; Fusco, P.; Giacomelli, G.; Giannini, G.; Giglietto, N.; Grassi, M.; Gray, L.; Grillo, A.; Guarino, F.; Guarnaccia, P.; Gustavino, C.; Habig, A.; Hanson, K.; Hawthorne, A.; Heinz, R.; Iarocci, E.; Katsavounidis, E.; Kearns, E.; Kyriazopoulou, S.; Lamanna, E.; Lane, C.; Levin, D. S.; Lipari, P.; Longley, N. P.; Longo, M. J.; Maaroufi, F.; Mancarella, G.; Mandrioli, G.; Manzoor, S.; Neri, A. Margiotta; Marini, A.; Martello, D.; Marzari-Chiesa, A.; Mazziotta, M. N.; Mazzotta, C.; Michael, D. G.; Mikheyev, S.; Miller, L.; Monacelli, P.; Montaruli, T.; Monteno, M.; Mufson, S.; Musser, J.; Nicolo, D.; Nolty, R.; Okada, C.; Orth, C.; Osteria, G.; Palamara, O.; Patera, V.; Patrizii, L.; Pazzi, R.; Peck, C. W.; Petrera, S.; Pistilli, P.; Popa, V.; Raino, A.; Rastelli, A.; Reynoldson, J.; Ronga, F.; Rubizzo, U.; Sanzgiri, A.; Satriano, C.; Satta, L.; Scapparone, E.; Scholberg, K.; Sciubba, A.; Serra-Lugaresi, P.; Severi, M.; Sioli, M.; Sitta, M.; Spinelli, P.; Spinetti, M.; Spurio, M.; Steinberg, R.; Stone, J. L.; Sulak, L. R.; Surdo, A.; Tarle, G.; Togo, V.; Walter, C. W.; Webb, R.

1999-01-01

With the aim of discussing the effect of the possible sources of systematic uncertainties in simulation models, the analysis of multiple muon events from the MACRO experiment at Gran Sasso is reviewed. In particular, the predictions from different currently available hadronic interaction models are compared

Anomalous correlation between hadrons and electromagnetic particles in hadron and gamma-ray families

International Nuclear Information System (INIS)

Tamada, Masanobu; Funayama, Yoshimi

1986-01-01

Correlations in relative (energy-weighted) distance between hadrons and electromagnetic particles are studied in the families observed in Chacaltaya emulsion chamber experiment. It is found that the observed number of hadrons which accompany electromagnetic in very close vicinity, say -5 , and it means there exists anomalous correlation between hadrons and electromagnetic particles in the characteristic spread of atmospheric electromagnetic cascade. The results are also compared with those of Japan-USSR joint chamber exposed at Pamir observatory. (author)

Measurement of Hadronic Event Shapes and Jet Substructure in Proton-Proton Collisions at 7.0 TeV Center-of-Mass Energy with the ATLAS Detector at the Large Hadron Collider

Energy Technology Data Exchange (ETDEWEB)

Miller, David Wilkins

2012-03-20

This thesis presents the first measurement of 6 hadronic event shapes in proton-proton collisions at a center-of-mass energy of {radical}s = 7 TeV using the ATLAS detector at the Large Hadron Collider. Results are presented at the particle-level, permitting comparisons to multiple Monte Carlo event generator tools. Numerous tools and techniques that enable detailed analysis of the hadronic final state at high luminosity are described. The approaches presented utilize the dual strengths of the ATLAS calorimeter and tracking systems to provide high resolution and robust measurements of the hadronic jets that constitute both a background and a signal throughout ATLAS physics analyses. The study of the hadronic final state is then extended to jet substructure, where the energy flow and topology within individual jets is studied at the detector level and techniques for estimating systematic uncertainties for such measurements are commissioned in the first data. These first substructure measurements in ATLAS include the jet mass and sub-jet multiplicity as well as those concerned with multi-body hadronic decays and color flow within jets. Finally, the first boosted hadronic object observed at the LHC - the decay of the top quark to a single jet - is presented.

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-12-17

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

CMS Hadron Endcap Calorimeter Upgrade Studies for Super-LHC

International Nuclear Information System (INIS)

Bilki, Burak

2011-01-01

When the Large Hadron Collider approaches Super-LHC conditions above a luminosity of 10 34 cm -2 s -1 , the scintillator tiles of the CMS Hadron Endcap calorimeters will lose their efficiencies. As a radiation hard solution, the scintillator tiles are planned to be replaced by quartz plates. In order to improve the efficiency of the photodetection, various methods were investigated including radiation hard wavelength shifters, p-terphenyl or 4% gallium doped zinc oxide. We constructed a 20 layer calorimeter prototype with pTp coated plates of size 20 cm x 20 cm, and tested the hadronic and the electromagnetic capabilities at the CERN H2 beam-line. The beam tests revealed a substantial light collection increase with pTp or ZnO:Ga deposited quartz plates. Here we report on the current R and D for a viable endcap calorimeter solution for CMS with beam tests and radiation damage studies.

Multiplicities of secondary hadrons produced in vp and overlinevp charged current interactions

Science.gov (United States)

Grässler, H.; Lanske, D.; Schulte, R.; Jones, G. T.; Middleton, R. P.; O'Neale, S. W.; Böckmann, K.; Gebel, W.; Geich-Gimbel, C.; Nellen, B.; Grant, A.; Klein, H.; Morrison, D. R. O.; Schmid, P.; Wachsmuth, H.; Chima, J. S.; Mobayyen, M. M.; Talebzadeh, M.; Villalobos-Baillie, O.; Aderholz, M.; Deck, L.; Schmitz, N.; Settles, R.; Wernhard, K. L.; Wittek, W.; Corrigan, G.; Myatt, G.; Radojicić, D.; Saitta, B.; Wells, J.; Aachen-Birmingham-Bonn-CERN-Imperial College-München (MPI)-Oxford Collaboration

1983-08-01

In an experiment with the hydrogen bubble chamber BEBC at CERN multiplicities of hadrons produced in νp and overlinevp interactions have been investigated. Results are presented on the multiplicities of charged hadrons and neutral pions, forward and backward multiplicities of charged hadrons and correlations between forward and backward multiplicities. Comparisons are made with hadronic reactions and e +e - annihilation. In the framework of the quark-parton model the data imply similar charged multiplicities for the fragments of a u- and a d-quark, and a larger multiplicities for the fragments of a uu- than for a ud-diquark. The correlation data suggest independent fragmentation of the quark and diquark for hadronic masses above ˜ 7 GeV and local charge compensation within an event.

Physical meaning of the yields from hadron-nucleon, hadron-nucleus, and nucleus-nucleus collisions observed in experiments

International Nuclear Information System (INIS)

Strugalski, Z.

1995-01-01

A physical meaning of the outcomes from hadronic and nuclear collision processes at high energies is presented, as prompted experimentally. The fast and slow stages in hadron-nucleus collisions are distinguished. Hadrons are produced via intermediate objects observed in hadron-nucleus collisions. The intermediate objects may be treated as the groups of quarks or the quark bags. 37 refs

Late effects from hadron therapy

Energy Technology Data Exchange (ETDEWEB)

Blakely, Eleanor A.; Chang, Polly Y.

2004-06-01

Successful cancer patient survival and local tumor control from hadron radiotherapy warrant a discussion of potential secondary late effects from the radiation. The study of late-appearing clinical effects from particle beams of protons, carbon, or heavier ions is a relatively new field with few data. However, new clinical information is available from pioneer hadron radiotherapy programs in the USA, Japan, Germany and Switzerland. This paper will review available data on late tissue effects from particle radiation exposures, and discuss its importance to the future of hadron therapy. Potential late radiation effects are associated with irradiated normal tissue volumes at risk that in many cases can be reduced with hadron therapy. However, normal tissues present within hadron treatment volumes can demonstrate enhanced responses compared to conventional modes of therapy. Late endpoints of concern include induction of secondary cancers, cataract, fibrosis, neurodegeneration, vascular damage, and immunological, endocrine and hereditary effects. Low-dose tissue effects at tumor margins need further study, and there is need for more acute molecular studies underlying late effects of hadron therapy.

GPU-Powered Modelling of Nonlinear Effects due to Head-On Beam-Beam Interactions in High-Energy Hadron Colliders.

CERN Document Server

Furuseth, Sondre

2017-01-01

The performance of high-energy circular hadron colliders, as the Large Hadron Collider, is limited by beam-beam interactions. The strongly nonlinear force between the two opposing beams causes diverging Hamiltonians and resonances, which can lead to a reduction of the lifetime of the beams. The nonlinearity makes the effect of the force difficult to study analytically, even at first order. Numerical models are therefore needed to evaluate the overall effect of different configurations of the machines. This report discusses results from an implementation of the weak-strong model, studying the effects of head-on beam-beam interactions. The assumptions has been shown to be valid for configurations where the growth and losses of the beam are small. The tracking has been done using an original code which applies graphic cards to reduce the computation time. The bunches in the beams have been modelled cylindrically symmetrical, based on a Gaussian distribution in three dimensions. This choice fits well with bunches...

Review of high energy hadron-nucleus data

Science.gov (United States)

Lissauer, D.

1987-01-01

In this review we will summarize new data on hardron-nucleus interactions. The possibility that quark-gluon plasma may be created in heavy ion collisions has led to renewed interest in hadron-nucleus collisions. In particular one hopes that understanding the energy loss of hadrons in h-A collissions will allow us to estimate the optimum energy in AA collisions in order to achieve maximum baryon and/or maximum energy density. This will allow us to choose the optimal experimental environment in the search for quark-gluon plasma. This review will thus omit many interesting results from hadron-nucleus collisions, such as the A dependence of lepton pair production, EMC effect and others. We will focus our attention on the following: (i) Estimating the rate of energy loss of the incident hadron as it propagates through the target. (ii) Determining where the enmergy is deposited in central hadron-nucleus collisions. It is clear that there is no direct or unique method of extrapolating our knowledge of h-A collisions to predict what will happen in AA-collisions. The knowledge and understanding of pp and pA collisions is, however, a useful and necessary guide to what one can expect in AA collisions. In this review we will concentrate on three experimental approaches to the study of h-A collisions. In Section 1 we will discuss the present status of pA → p + X inclusive measurements. In Section 2 measurements from visual detectors, in this case results from the 30″ hybrid spectrometer, which allows investigations of global event properties will be presented. In Section 3 data using 2π calorimeters, where one can trigger and measure transverse energy and energy flow over a given rapidity region, will be discussed. The conclusions will be given in Section 4.

Bottom-hadron production through top quark decay

Energy Technology Data Exchange (ETDEWEB)

Moosavi Nejad, Seyed Mohammad

2009-06-15

In this thesis we apply perturbative QCD to make precise predictions for some observables in high-energy processes involving bottom-quark. Our first application is a prediction for the energy spectrum of b-flavored hadrons in top quark decay. For that purpose we calculate at NLO the OCD corrections for bottom fragmentation in top decay. The b-quark in the top quark decay is considered once as a massless and once as a massive particle in our calculations. The difference between the differential width calculated in both cases can give us the perturbative fragmentation function of the b-quark. After that using the obtained differential widths and applying ZM-VFNS and GM-VFNS, we make some predictions for the spectrum of B-hadrons produced in top quark decay. The comparison of both approaches shows that the mass effect of the b-quark in the top quark decay is negligible. We also investigate the mass effect of B-hadron in the energy distribution obtained in the previous calculations and we show that this increases the value of the differential width when the energy taken away by the produced parton in top decay is small. Our second application is to obtain the helicity contributions of the W{sup +}-boson in the energy distribution of b-flavored hadrons in top quark decay. For this reason we study the angular decay distribution for the cascade decay of the top-quark (t{yields} b+W{sup +}({yields}e{sup +}+{nu}{sub e})). Using ZM-VFNS we make predictions for the NLO contributions of the longitudinal, the transverse-minus and the transverse-plus helicity of the W{sup +}-boson in the energy distribution of B-hadron. (orig.)

Challenges in Hadron Physics

OpenAIRE

Meißner, Ulf-G.

2004-01-01

The status of hadron physics at the end of the HADRON07 Conference is reviewed. The latest results presented at the conference, as well as those important developments in the field which were not represented, are included.

Study of Hadron Production in Hadron-Nucleus and Nucleus-Nucleus Collisions at the CERN SPS

CERN Multimedia

Klochkov, V; Herve, A E; Kowalski, S; Kaptur, E A; Kowalik, K L; Dominik, W M; Matulewicz, T N; Krasnoperov, A; Feofilov, G; Vinogradov, L; Kovalenko, V; Johnson, S R; Planeta, R J; Rubbia, A; Marton, K; Messerly, B A; Puzovic, J; Bogomilov, M V; Bravar, A; Renfordt, R A E; Deveaux, M; Engel, R R; Grzeszczuk, A; Davis, N; Kuich, M; Lyubushkin, V; Kondratev, V; Kadija, K; Diakonos, F; Slodkowski, M A; Rauch, W H; Pistillo, C; Laszlo, A; Nakadaira, T; Hasegawa, T; Sadovskiy, A; Morozov, S; Petukhov, O; Mathes, H; Roehrich, D; Marcinek, A J; Marino, A D; Grebieszkow, K; Di luise, S; Wlodarczyk, Z; Rybczynski, M A; Wojtaszek-szwarc, A; Nirkko, M C; Sakashita, K; Golubeva, M; Kurepin, A; Manic, D; Kolev, D I; Kisiel, J E; Koziel, M E; Rondio, E; Larsen, D T; Czopowicz, T R; Seyboth, P; Turko, L; Guber, F; Marin, V; Busygina, O; Strikhanov, M; Taranenko, A; Cirkovic, M; Roth, M A; Pulawski, S M; Aduszkiewicz, A M; Bunyatov, S; Vechernin, V; Nagai, Y; Anticic, T; Dynowski, K M; Mackowiak-pawlowska, M K; Stefanek, G; Pavin, M; Fodor, Z P; Nishikawa, K; Tada, M; Blondel, A P P; Stroebele, H W; Posiadala, M Z; Kolesnikov, V; Andronov, E; Zimmerman, E D; Antoniou, N; Majka, Z; Dumarchez, J; Naskret, M; Ivashkin, A; Tsenov, R V; Koziel, M G; Schmidt, K J; Melkumov, G; Popov, B; Panagiotou, A; Richter-was, E M; Morgala, S J; Paolone, V; Damyanova, A; Gazdzicki, M; Unger, M T; Wilczek, A G; Stepaniak, J M; Seryakov, A; Susa, T; Staszel, P P; Brzychczyk, J; Maksiak, B; Tefelski, D B

2007-01-01

The NA61/SHINE (SHINE = SPS Heavy Ion and Neutrino Experiment) experiment is a large acceptance hadron spectrometer at the CERN SPS for the study of the hadronic final states produced in interactions of various beam particles (pions, protons, C, S and In) with a variety of fixed targets at the SPS energies. The main components of the current detector were constructed and used by the NA49 experiment. The physics program of NA61/SHINE consists of three main subjects. In the first stage of data taking (2007-2009) measurements of hadron production in hadron-nucleus interactions needed for neutrino (T2K) and cosmic-ray (Pierre Auger and KASCADE) experiments will be performed. In the second stage (2009-2011) hadron production in proton-proton and proton-nucleus interactions needed as reference data for a better understanding of nucleus-nucleus reactions will be studied. In the third stage (2009-2013) energy dependence of hadron production properties will be measured in nucleus-nucleus collisions as well as in p+p a...

Study of the hadronisation process from single hadron and hadron-pair production in SIDIS at COMPASS

CERN Document Server

Makke, Nour

2014-01-01

Hadron production in hard scattering reactions is described by the hadronization mechanism which combines quarks into final-state hadrons. Within the theoretical framework of leading-twist collinear QCD, the cross section for hadron production in semi-inclusive deep-inelastic scattering can be factorized into a hard scattering cross section describing the hard interaction at the quark level calculable in perturbative QED, and non-perturbative universal functions: parton distribution functions which reflect the quark structure of initial-state hadrons and collinear fragmentation functions which encode details on the hadronization process. In the last decades, a major effort has been achieved on theoretical and experimental levels and allowed to constraint, with very high precision, parton distribution functions except strange quark distribution, which still carries large uncertainties. Fragmentation functions, however, remain at a very preliminary stage of study with a growing interest in a more accurate and p...

Contribution to the energy calibration of GLAST-LAT's calorimeter and validation of hadronic cascade models available with GEANT4

International Nuclear Information System (INIS)

Bregeon, J.

2005-09-01

GLAST is the new generation of Gamma-ray telescope and should dramatically improve our knowledge of the gamma-ray sky when it is launched on September 7. 2007. Data from the beam test that was held at GANIL with low energy ions were analyzed in order to measure the light quenching factor of CsI for all kinds of ions from proton to krypton of energy between 0 and 73 MeV per nucleon. These results have been very useful to understand the light quenching for relativistic ions that was measured during the GSI beam test. The knowledge of light quenching in GLAST CsI detectors for high energy ions is required for the on-orbit calibration with cosmic rays to succeed. Hadronic background rejection is another major issue for GLAST, thus, all the algorithms rely on the GLAST official Monte-Carlo simulation, GlastRelease. Hadronic cascade data from the GSI beam test and from another beam test held at CERN on the SPS have been used to benchmark hadronic cascade simulation within the framework of GEANT4, on which GlastRelease is based. Testing the good reproduction of simple parameters in GLAST-like calorimeters for hadronic cascades generated by 1.7 GeV, 3.4 GeV, 10 GeV and 20 GeV protons or pions led us to the conclusion that at high energy the default LHEP model is good enough, whereas at low energy the Bertini intra-nuclear cascade model should be used. (author)

Charmed hadrons in nuclear medium

International Nuclear Information System (INIS)

Tolos, L.; Gamermann, D.; Molina, R.; Nieves, J.; Oset, E.; Garcia-Recio, C.; Ramos, A.

2010-01-01

We study the properties of charmed hadrons in dense matter within a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner. We analyze the behaviour in this dense environment of dynamically-generated baryonic resonances as well as the open-charm meson spectral functions. We discuss the implications of the in-medium properties of open-charm mesons on the D s0 (2317) and the predicted X(3700) scalar resonances. (authors)

The effect of vector meson decays on di-hadron fragmentation functions

International Nuclear Information System (INIS)

Matevosyan, H.H.; Thomas, A.W.; Bentz, W.

2014-01-01

Di-hadron Fragmentation Functions (DFF) provide a vast amount of information on the intricate details of the parton hadronization process. Moreover, they provide a unique access to the 'clean' extraction of nucleon transversity parton distribution functions in semi inclusive deep inelastic two hadron production process with a transversely polarised target. On the example of the u → π + π - we analyse the properties of unpolarized DFFs using their probabilistic interpretation. We use both the NJL-jet hadronization model and PYTHIA 8.1 event generator to explore the effect of the strong decays of the vector mesons produced in the quark hadronization process on the pseudoscalar DFFs. Our study shows that, even though it is less probable to produce vector mesons in the hadronization process than pseudo scalar mesons of the same charge, the products of their strong decays drastically affect the DFFs for pions because of the large combinatorial factors. Thus, an accurate description of both vector meson production and decays are crucial for theoretical understanding of DFFs. (authors)

Analysis of elastic interactions of hadrons at high energies

International Nuclear Information System (INIS)

Yuldashev, B.S.; Fazilova, Z.F.; Ismatov, E.I.; Kurmanbai, M.S.; Ajniyazova, G.T.; Tskhay, K.V.; Medeuova, A.B.

2004-01-01

Study of elastic interactions of hadrons at high energies if of great interest due to the fact that the amplitude of this process is the simplest, and at the same time, it is a fundamental object for theoretical and experimental researches. Study of this process allows one to have a quantitative check of various theories and models, and to make a critical selection. By using of fundamental property of theory - unitarity condition of scattering matrix - elastic scattering can be connected with inelastic reaction. Based on S-channel unitarity condition expressing elastic amplitude via inelastic overlapping function, to study the latter, as well as to describe the experimentally measured characteristics of hadron-nucleon interactions at high-energies, as well as for results prediction. By using experimental data on differential cross-section of elastic scattering of hadrons at various energies and by theoretical information on ratio of a real part and an imaginary part of scattering amplitude δ(t) the t-dependence of inelastic and elastic overlapping functions is studied. Influence of a zigzag form of differential cross-section of elastic pp(p) scattering on profile function and inelastic overlapping function to violation of geometric scaling was studied. In frames of the scaling the general expressions for s- and t-dependences of inelastic overlapping function are derived. Comparison of this function in three elastic scattering models was carried out. It was demonstrated that one would need to assume that hadrons become blacker at central part in order to correctly describe experimental angular distribution data. Dependence of differential cross-section on transfer momentum square for elastic hadrons scattering at energies of ISR and SPS in the model of inelastic overlapping function is studied. (author)

Analysis of elastic interactions of hadrons at high energies

International Nuclear Information System (INIS)

Fazylov, M.I.; Yuldashev, B.S.; Azhniyazova, G.T.; Ismatov, E.I.; Sartbay, T.; Kurmanbay, M.S.; Tskhay, K.V.

2004-01-01

Full text: Study of elastic interactions of hadrons at high energies if of great interest due to the fact that the amplitude of this process is the simplest, and at the same time, it is a fundamental object for theoretical and experimental researches. Study of this process allows one to have a quantitative check of various theories and models, and to make a critical selection. By using of fundamental property of theory - unitarity condition of scattering matrix - elastic scattering can be connected with inelastic reaction. Based on S-channel unitarity condition expressing elastic amplitude via inelastic overlapping function, to study the latter, as well as to describe the experimentally measured characteristics of hadron-nucleon interactions at high-energies, as well as for results prediction. By using experimental data on differential cross-section of elastic scattering of hadrons at various energies and by theoretical information on ratio of a real part and an imaginary part of scattering amplitude δ(t) the t-dependence of inelastic and elastic overlapping functions is studied. Influence of a zigzag form of differential cross-section of elastic pp(p) scattering on profile function and inelastic overlapping function to violation of geometric scaling was studied. In frames of the scaling the general expressions for s- and t-dependences of inelastic overlapping function are derived. Comparison of this function in three elastic scattering models was carried out. It was demonstrated that one would need to assume that hadrons become blacker at central part in order to correctly describe experimental angular distribution data. Dependence of differential cross-section on transfer momentum square for elastic hadrons scattering at energies of ISR and SPS in the model of inelastic overlapping function is studied

Particle theory and intense hadron facilities

International Nuclear Information System (INIS)

Ng, J.N.

1989-05-01

A brief overview of particle physics that can be done at an intense hadron facility (IHF) is given. The emphasis is placed on testing the standard model, light Higgs boson searches and CP violation, which are areas an IHF can do especially well

Dynamical theory of hadrons based upon extended particle picture

International Nuclear Information System (INIS)

Hara, Osamu

1980-01-01

An extended particle model of hadrons is discussed on the basis of the assumption that the hadrons correspond to the respective eigenstates of the internal motion of extended bodies which are considered as deformable spheres for simplicity. Such three-dimensionally extended bodies have several remarkable features. The first point is that it is allowed to make half-integer spin. The internal motion of the bodies can be described in terms of quark-like excitons. But the great difference is that these quark-like excitons obey Bose statistics. Therefore in this model, there is no positive reason to introduce the degree of freedom of color at least from the symmetry reason. The second point is that the triality must be restricted to zero. Therefore, the particles with fractional charge do not appear, and the confinement is automatic. It is assumed that the interaction among hadrons takes place due to the coupling of current carried by excited quark-like excitons. All hadron interactions are described in terms of a single coupling constant characterizing the coupling between current and intermediate field. Once the interaction Hamiltonian is given, it is straight forward to calculate scattering amplitude. High energy charge exchange scattering and the decay width of higher resonances can be understood. (Kako, I.)

Hadron accelerators in medicine

International Nuclear Information System (INIS)

Amaldi, U.

1996-01-01

The application of hadron accelerators (protons and light ions) in cancer therapy is discussed. After a brief introduction on the rationale for the use of heavy charged particles in radiation therapy, a discussion is given on accelerator technology and beam delivery systems. Next, existing and planned facilities are briefly reviewed. The Italian Hadron-therapy Project is then described in some detail, with reference ro both the National Centre for Oncological Hadron-therapy and the design of different types of compact proton accelerators aimed at introducing proton therapy in a large umber of hospitals. (author)

Particle production in hadron--nucleus collisions above 10 GeV

International Nuclear Information System (INIS)

Busza, W.

1978-01-01

The reasons for interest in the observed phenomena in hadron reactions above 10 GeV are considered. The latest data are not reviewed except for comparison with theoretical models. Among the topics considered are total or absorption cross sections, low average multiplicity, nuclear fragment distributions, implications for the nature of hadrons and their interactions, rapidity distributions, and multiple production energy dependence. 38 references

Mass differences of light hadron isomultiplets

International Nuclear Information System (INIS)

Palladino, B.E.; Ferreira, P.L.

1989-01-01

Mass differences of low-lying, non-strange, hadron isomultiplets are investigated in the framework of a relativistic, independent quark potential model, implemented by center-of-mass, one-gluon-exchange and pion-cloud corrections. The introduction of pionic self-energy corrections with non-degenerate intermediate states is instrumental in our analysis, playing also a fundamental role for a successful description of the ρ-ω mass splitting. The effect of the supersposition of all these corrections is discussed in some detail for the p-n, Π + -Π 0 , ρ + -ρ 0 and Δ ++ -Δ 0 mass differences. The corresponding hadronic masses are also calculated with suitable values for the hardronic sizes and quark masses. (author) [pt

Relevance of the hadronic interaction model in the interpretation of multiple muon data as detected with the MACRO experiment

CERN Document Server

Ambrosio, M; Aramo, C; Auriemma, G; Baldini, A; Barbarino, G C; Barish, B C; Battistoni, G; Bellotti, R; Bemporad, C; Bernardini, P; Bilokon, H; Bisi, V; Bloise, C; Bower, C; Bussino, S; Cafagna, F; Calicchio, M; Campana, D; Carboni, M; Castellano, M G; Cecchini, S; Cei, F; Chiarella, V; Coutu, S; De Benedictis, L; De Cataldo, G; Dekhissi, H; De Marzo, C; De Mitri, I; De Vincenzi, M; Di Credico, A; Erriquez, O; Favuzzi, C; Forti, C; Fusco, P; Giacomelli, G; Giannini, G; Giglietto, N; Grassi, M; Gray, L; Grillo, A; Guarino, F; Guarnaccia, P; Gustavino, C; Habig, A; Hanson, K; Hawthorne, A; Heinz, R; Iarocci, Enzo; Katsavounidis, E; Kearns, E T; Kyriazopoulou, S; Lamanna, E; Lane, C; Levin, D S; Lipari, P; Longley, N P; Longo, M J; Maaroufi, F; Mancarella, G; Mandrioli, G; Manzoor, S; Margiotta-Neri, A; Marini, A; Martello, D; Marzari-Chiesa, A; Mazziotta, M N; Mazzotta, C; Michael, D G; Mikheyev, S P; Miller, L; Monacelli, P; Montaruli, T; Monteno, M; Mufson, S L; Musser, J; Nicolò, D; Nolty, R; Okada, C; Orth, C; Osteria, G; Palamara, O; Patera, V; Patrizii, L; Pazzi, R; Peck, C W; Petrera, S; Pistilli, P; Popa, V; Rainó, A; Rastelli, A; Reynoldson, J; Ronga, F; Rubizzo, U; Sanzgiri, A; Satriano, C; Satta, L; Scapparone, E; Scholberg, K; Sciubba, A; Serra-Lugaresi, P; Severi, M; Sioli, M; Sitta, M; Spinelli, P; Spinetti, M; Spurio, M; Steinberg, R; Stone, J L; Sulak, Lawrence R; Surdo, A; Tarle, G; Togo, V; Walter, C W; Webb, R

1999-01-01

With the aim of discussing the effect of the possible sources of systematic uncertainties in simulation models, the analysis of multiple muon events from the MACRO experiment at Gran Sasso is reviewed. In particular, the predictions $9 from different currently available hadronic interaction models are compared. (9 refs).

Effective field theory approach to parton-hadron conversion in high energy QCD processes

CERN Document Server

Kinder-Geiger, Klaus

1995-01-01

A QCD based effective action is constructed to describe the dynamics of confinement and symmetry breaking in the process of parton-hadron conversion. The deconfined quark and gluon degrees of freedom of the perturbative QCD vacuum are coupled to color singlet collective fields representing the non-perturbative vacuum with broken scale and chiral symmetry. The effective action recovers QCD with its scale and chiral symmetry properties at short space-time distances, but yields at large distances (r > 1 fm) to the formation of symmetry breaking gluon and quark condensates. The approach is applied to the evolution of a fragmenting q\\bar q pair with its generated gluon distribution, starting from a large hard scale Q^2. The modification of the gluon distribution arising from the coupling to the non-perturbative collective field results eventually in a complete condensation of gluons. Color flux tube configurations of the gluons in between the q\\bar q pair are obtained as solutions of the equations of motion. With ...

Dependence of elastic hadron collisions on impact parameter

Science.gov (United States)

Procházka, Jiří; Lokajíček, Miloš V.; Kundrát, Vojtěch

2016-05-01

Elastic proton-proton collisions represent probably the greatest ensemble of available measured data, the analysis of which may provide a large amount of new physical results concerning fundamental particles. It is, however, necessary to analyze first some conclusions concerning pp collisions and their interpretations differing fundamentally from our common macroscopic experience. It has been argued, e.g., that elastic hadron collisions have been more central than inelastic ones, even if any explanation of the existence of so different processes, i.e., elastic and inelastic (with hundreds of secondary particles) collisions, under the same conditions has not been given until now. The given conclusion has been based on a greater number of simplifying mathematical assumptions (already done in earlier calculations), without their influence on physical interpretation being analyzed and entitled; the corresponding influence has started to be studied in the approach based on the eikonal model. The possibility of a peripheral interpretation of elastic collisions will be demonstrated and the corresponding results summarized. The arguments will be given on why no preference may be given to the mentioned centrality against the standard peripheral behaviour. The corresponding discussion on the contemporary description of elastic hadronic collision in dependence on the impact parameter will be summarized and the justification of some important assumptions will be considered.

Forward charge distributions associated with hadronically produced J/psi particles

International Nuclear Information System (INIS)

Budd, H.S.

1983-01-01

We have measured the forward charge as a function of x/sub F/ of the psi for events produced by 225 Gev/c π-Be interactions. The forward charge is the average difference between the number of positive hadrons and negative hadrons produced in the forward hemisphere. The standard Drell-Yan model predicts that the forward charge should become less negative as the x/sub F/ of the J/psi increases. The measured forward charge becomes more negative as the x/sub F/ of the J/psi increases although it is consistent with being flat as a function of x/sub F/. Hence the data is not consistent with any Drell-Yan type model which assumes the forward charge is not strongly dependent on the hadronic energy left over after the J/psi is formed. 45 references

W gamma production in hadronic collisions using the POWHEG+MiNLO method

CERN Document Server

Barze, Luca; Montagna, Guido; Nason, Paolo; Nicrosini, Oreste; Piccinini, Fulvio; Prosperi, Valeria

2014-01-01

We detail a calculation of W gamma production in hadronic collision, at Next-to-Leading Order (NLO) QCD interfaced to a shower generator according to the POWHEG prescription supplemented with the MiNLO procedure. The fixed order result is matched to an interleaved QCD+QED parton shower, in such a way that the contribution arising from hadron fragmentation into photons is fully modeled. In general, our calculation illustrates a new approach to the fully exclusive simulation of prompt photon production processes accurate at the NLO level in QCD. We compare our predictions to those of the NLO program MCFM, which treats the fragmentation contribution in terms of photon fragmentation functions. We also perform comparisons to available LHC data at 7 TeV, for which we observe good agreement, and provide phenomenological results for physics studies of the W gamma production process at the Run II of the LHC. The new tool, which includes W leptonic decays and the contribution of anomalous gauge couplings, allows a full...

Weak-electromagnetic interference effects in the production of hadrons in electron-positron collisions

International Nuclear Information System (INIS)

Nieves, J.F.

1980-01-01

A framework for a systematic study of the weak-electromagnetic interference effects in the production of hadrons in e - e + collisions is presented and, in the case of the inclusive processes, the predictions of the quark-parton model are given. The approach to the calculation of these effects in e - e + H + X, where H is a pseudoscalar meson, a spin-1/2 baryon, or a vector meson, consists of setting down a general formula for the appropriate transition probability in terms of structure functions whose form is delimited by symmetry considerations. The quark-parton model is then used to express the structure functions in terms of the quark couplings and fragmentation probabilities. In this fashion the forward-backward asymmetry A/sub H/ and longitudinal polarization P/sub H/ are calculated in terms of the vector (a/sub q/) and axial-vector (b/sub q/) weak-neutral-current couplings of the quarks composing H, their electric charges Q/sub q/, and their (q → H) fragmentation probabilities. Using a theoretical argument for hadrons containing one heavy c,b,...quark, and SU(3) symmetry for hadrons composed of light u,d,s quarks, A/sub H/ is expressed in terms of b/sub q/ and Q/sub q/ only. In similar fashion, some relations between the various P/sub H/, independent of the fragmentation probabilities, are obtained. The results are discussed in detail for the strange and charmed hadrons.The exclusive processes e - e + → M anti M and e - e + → MV, where M is a pseudoscalar meson and V is a vector meson, are also discussed and the possibility of observing the weak-electromagnetic interference effects when M and V contain the t quark is noted

Higgs physics with hadronic signatures at ATLAS and CMS

CERN Document Server

Schroder, Matthias

2018-01-01

Precise measurement of the properties of the Higgs boson is of paramount interest in order to verify the standard model nature of the Higgs sector or discover new physics. Crucial information is obtained from investigation of hadronic final states, which offer, for example, a direct probe of the couplings to top or bottom quarks. In this article, latest results of Higgs boson measurements with hadronic signatures by ATLAS and CMS at the LHC are reviewed.

Transverse Momentum Correlations in Hadronic Z decays

CERN Document Server

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

1997-01-01

Using data obtained with the ALEPH detector at the Z resonance, a measure based on transverse momentum is shown to exhibit a correlation between the two halves of a hadronic event which cannot be explained by energy-momentum conservation, flavour conservation, the imposition of an event axis or imperfect event reconstruction. Two possible explanations based on Monte Carlo models are examined: a) ARIADNE, with the correlation forming early in the parton shower and with the transition from partons to hadrons playing only a minor part; b) JETSET, with the correlation forming at the fragmentation stage. A correlation technique based on a jet cluster analysis is used to make a comparison of the models with the data. It is concluded that both non-perturbative and perturbative effects make important contributions to the observed correlation.

Probing leptophilic dark sectors with hadronic processes

Science.gov (United States)

D'Eramo, Francesco; Kavanagh, Bradley J.; Panci, Paolo

2017-08-01

We study vector portal dark matter models where the mediator couples only to leptons. In spite of the lack of tree-level couplings to colored states, radiative effects generate interactions with quark fields that could give rise to a signal in current and future experiments. We identify such experimental signatures: scattering of nuclei in dark matter direct detection; resonant production of lepton-antilepton pairs at the Large Hadron Collider; and hadronic final states in dark matter indirect searches. Furthermore, radiative effects also generate an irreducible mass mixing between the vector mediator and the Z boson, severely bounded by ElectroWeak Precision Tests. We use current experimental results to put bounds on this class of models, accounting for both radiatively induced and tree-level processes. Remarkably, the former often overwhelm the latter.

S -wave K π contributions to the hadronic charmonium B decays in the perturbative QCD approach

Science.gov (United States)

Rui, Zhou; Wang, Wen-Fei

2018-02-01

We extend our recent works on the two-pion S -wave resonance contributions to the kaon-pion ones in the B meson hadronic charmonium decay modes based on the perturbative QCD approach. The S -wave K π timelike form factor in its distribution amplitudes is described by the LASS parametrization, which consists of the K0*(1430 ) resonant state together with an effective range nonresonant component. The predictions for the decays B →J /ψ K π in this work agree well with the experimental results from the BABAR and Belle collaborations. We also discuss theoretical uncertainties, indicating that the results of this work, which can be tested by the LHCb and Belle-II experiments, are reasonably accurate.

Bulk and shear viscosities of hot and dense hadron gas

International Nuclear Information System (INIS)

Kadam, Guru Prakash; Mishra, Hiranmaya

2015-01-01

We estimate the bulk and the shear viscosity at finite temperature and baryon densities of hadronic matter within a hadron resonance gas model which includes a Hagedorn spectrum. The parameters of the Hagedorn spectrum are adjusted to fit recent lattice QCD simulations at finite chemical potential. For the estimation of the bulk viscosity we use low energy theorems of QCD for the energy momentum tensor correlators. For the shear viscosity coefficient, we estimate the same using molecular kinetic theory to relate the shear viscosity coefficient to average momentum of the hadrons in the hot and dense hadron gas. The bulk viscosity to entropy ratio increases with chemical potential and is related to the reduction of velocity of sound at nonzero chemical potential. The shear viscosity to entropy ratio on the other hand, shows a nontrivial behavior with the ratio decreasing with chemical potential for small temperatures but increasing with chemical potential at high temperatures and is related to decrease of entropy density with chemical potential at high temperature due to finite volume of the hadrons

The time structure of hadronic showers in highly granular calorimeters with tungsten and steel absorbers

Czech Academy of Sciences Publication Activity Database

Adloff, C.; Blaising, J.J.; Chefdeville, M.; Cvach, Jaroslav; Gallus, Petr; Havránek, Miroslav; Janata, Milan; Kvasnička, Jiří; Lednický, Denis; Marčišovský, Michal; Polák, Ivo; Popule, Jiří; Tomášek, Lukáš; Tomášek, Michal; Růžička, Pavel; Šícho, Petr; Smolík, Jan; Vrba, Václav; Zálešák, Jaroslav

2014-01-01

Roč. 9, Jul (2014), s. 1-24 ISSN 1748-0221 R&D Projects: GA MŠk LG14033 Institutional support: RVO:68378271 Keywords : hadronic calorimeter s * hadronic showers * hadronic physics models * hilicon photomultiplier Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.399, year: 2014

Searches for Natural Supersymmetry in Hadronic Final States with Heavy Flavor at ATLAS

Energy Technology Data Exchange (ETDEWEB)

Butler, Bart Clayton [Stanford Univ., CA (United States)

2012-12-01

This thesis presents the hadronic-channel supersymmetric searches for direct sbottom and gluino-mediated sbottom and stop production performed on 4.71 fb^-1 of √s = 7 TeV data collected by the ATLAS detector at the Large Hadron Collider. These signatures are characterized by final states with multiple b-tagged jets and missing transverse energy ( E_T ) and the analysis strategy is chosen accordingly. Particular emphasis is placed on the utilization of the simplified models approach in signal characterization, optimization, and interpretation of results. No significant excess is observed resulting in limits set at 95% confidence level. Relative to the previous versions of the analyses, this iteration represents a several-fold increase in sensitivity to the new physics signatures considered. This is largely due to the use of three b-tag signal regions as well as signal regions based on initial state radiation.

Recognizing Critical Behavior amidst Minijets at the Large Hadron Collider

Directory of Open Access Journals (Sweden)

Rudolph C. Hwa

2015-01-01

Full Text Available The transition from quarks to hadrons in a heavy-ion collision at high energy is usually studied in two different contexts that involve very different transverse scales: local and nonlocal. Models that are concerned with the pT spectra and azimuthal anisotropy belong to the former, that is, hadronization at a local point in (η,ϕ space, such as the recombination model. The nonlocal problem has to do with quark-hadron phase transition where collective behavior through near-neighbor interaction can generate patterns of varying sizes in the (η,ϕ space. The two types of problems are put together in this paper both as brief reviews separately and to discuss how they are related to each other. In particular, we ask how minijets produced at LHC can affect the investigation of multiplicity fluctuations as signals of critical behavior. It is suggested that the existing data from LHC have sufficient multiplicities in small pT intervals to make the observation of distinctive features of clustering of soft particles, as well as voids, feasible that characterize the critical behavior at phase transition from quarks to hadrons, without any ambiguity posed by the clustering of jet particles.

Associated production of a quarkonium and a Z boson at one loop in a quark-hadron-duality approach

CERN Document Server

Lansberg, Jean-Philippe

2016-01-01

In view of the large discrepancy about the associated production of a prompt $J/\\psi$ and a $Z$ boson between the ATLAS data at $\\sqrt{s}=8$ TeV and theoretical predictions for Single Parton Scattering (SPS) contributions, we perform an evaluation of the corresponding cross section at one loop accuracy (Next-to-Leading Order, NLO) in a quark-hadron-duality approach, also known as the Colour-Evaporation Model (CEM). This work is motivated by (i) the extremely disparate predictions based on the existing NRQCD fits conjugated with the absence of a full NLO NRQCD computation and (ii) the fact that we believe that such an evaluation provides a likely upper limit of the SPS cross section. In addition to these theory improvements, we argue that the ATLAS estimation of the Double Parton Scattering (DPS) yield may be underestimated by a factor as large as 3 which then reduces the size of the SPS yield extracted from the ATLAS data. Our NLO SPS evaluation also allows us to set an upper limit on $\\sigma_{\\rm eff}$ drivi...

Hadronic matrix elements in the QCD on the lattice

International Nuclear Information System (INIS)

Altmeyer, R.

1995-01-01

The work describes a lattice simulation of full QCD with dynamical Kogut-Susskind fermions. We evaluated different hadronic matrix elements which are related to the static and low-energy behaviour of hadrons. The analysis was performed on a 16 3 x 24 lattice with a coupling constant of β = 5.35 and a quark mass of m = 0.010. The calculations are based on a set of 85 configurations created by using a Hybrid-Monte-Carlo algorithm. First we evaluated the mass and energy spectrum of the low-lying hadrons using local operators as well as non-local operators. As the complete spectrum of the different pion and ρ meson lattice representations has been calculated we were able to check the restoration of continuum flavor symmetry. Moreover, the determination of energies E of hadron states with non-vanishing momentum vector q made it possible to investigate the lattice dispersion function E( vector q). Another part of the presented work is the determination of mesonic decay constants which parameterise the weak decay of mesons. They are related to hadronic matrix elements of the respective quark currents and through the calculation of these matrix elements we were able to determine the decay constants f π and f ρ . Before doing so, we calculated non-perturbatively renormalization constants for the currents under consideration. The next part is the determination of hadronic coupling constants. These parameterise in an effective low-energy model the interactions of different hadrons. They are related to hadronic matrix elements whose lattice calculation can be dpme bu evaluating 3-point correlation functions. Thus we evaluted the hadronic coupling constants g ρππ and g NNπ . Finally, an investigation of the pion-nucleon σterm was done. The σterm is defined through a hadronic matrix element of a quark-antiquark operator and can thus be evaluated on the lattice via the calculation of a 3-point correlation function. As we determined the connected and the disconnected

A study of correlations between identified charged hadrons in hadronic Z0 decays

International Nuclear Information System (INIS)

Abe, K.; Abe, K.; Abe, T.

1998-06-01

The authors present a preliminary study of correlations in rapidity between pairs of identified pions, kaons and protons in hadronic Z 0 decays into light flavors. Short range charge correlations are observed between all combinations of these hadron species, confirming that charge, strangeness and baryon number are conserved locally in the jet fragmentation process. The range of this effect is found to be independent of momentum. A strong long-range correlation is observed for high-momentum charged kaon pairs, and weaker long-range π + -π - , π + -K - and p-K - correlations are observed. The SLC electron beam polarization is used to tag the quark hemisphere in each event, allowing the first study of rapidities signed such that positive rapidity is along the quark rather than antiquark direction. Distributions of signed rapidities and of ordered differences between signed rapidities provide new insights into leading particle production and several new tests of fragmentation models

Hadron production by virtual photons in the quark fragmentation region

International Nuclear Information System (INIS)

Scarr, J.M.; Chen, C.K.; Knowles, J.; Martin, D.; Skillicorn, I.O.; Smith, K.; Joos, P.; Ladage, A.; Meyer, H.; Wolf, G.

1977-11-01

We have measured the inclusive electroproduction of positive and negative hadrons in the quark fragmentation region using the streamer chamber at DESY. Data are presented in terms of the variable zsub(p) = p/ν in the kinematic region 1.8 2 2 . The positive hadron distributions contain a strong proton component. After subtraction of the proton component and elastic rho events, the distribution 1/sigma sub(tot) (dsigma/dz sub(p)) for positive and negative hadrons agrees well with the corresponding distribution from e + e - annihilation (DORIS data). This behaviour supports the validity of the quark parton model at surprisingly low Q 2 and W. (orig.) [de

Observation of charmless hadronic B decays

CERN Document Server

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

1996-01-01

Four candidates for charmless hadronic B decay are observed in a data sample of four million hadronic Z decays recorded by the {\\sc aleph} detector at {\\sc lep} . The probability that these events come from background sources is estimated to b e less than $10^{-6}$. The average branching ratio of weakly decaying B hadrons (a mixture of $\\bd$, $\\bs$ and $\\lb$ weighted by their production cross sections and lifetimes , here denoted B) into two long-lived charged hadrons (pions, kaons or protons) is measured to be $\\Br(\\btohh) = \\resultBR$. The relative branching fraction $\\rratio$, where $\\rs$ is the ratio of $\\bs$ to $\\bd$ decays in the sample, is measured to be $\\resultR$. %Branching ratio upper limits are also obtained for a variety In addition, branching ratio upper limits are obtained for a variety of exclusive charmless hadronic two-body decays of B hadrons.

Hard QCD at hadron colliders

Energy Technology Data Exchange (ETDEWEB)

Moch, S

2008-02-15

We review the status of QCD at hadron colliders with emphasis on precision predictions and the latest theoretical developments for cross sections calculations to higher orders. We include an overview of our current information on parton distributions and discuss various Standard Model reactions such as W{sup {+-}}/Z-boson, Higgs boson or top quark production. (orig.)

Hard QCD at hadron colliders

International Nuclear Information System (INIS)

Moch, S.

2008-02-01

We review the status of QCD at hadron colliders with emphasis on precision predictions and the latest theoretical developments for cross sections calculations to higher orders. We include an overview of our current information on parton distributions and discuss various Standard Model reactions such as W ± /Z-boson, Higgs boson or top quark production. (orig.)

PREFACE: Focus section on Hadronic Physics

Science.gov (United States)

Roberts, Craig; Swanson, Eric

2007-07-01

Hadronic physics is the study of strongly interacting matter and its underlying theory, Quantum Chromodynamics (QCD). The field had its beginnings after World War Two, when hadrons were discovered in ever increasing numbers. Today, it encompasses topics like the quark-gluon structure of hadrons at varying scales, the quark-gluon plasma and hadronic matter at extreme temperature and density; it also underpins nuclear physics and has significant impact on particle physics, astrophysics, and cosmology. Among the goals of hadronic physics are to determine the parameters of QCD, understand the origin and characteristics of confinement, understand the dynamics and consequences of dynamical chiral symmetry breaking, explore the role of quarks and gluons in nuclei and in matter under extreme conditions and understand the quark and gluon structure of hadrons. In general, the process is one of discerning the relevant degrees of freedom and relating these to the fundamental fields of QCD. The emphasis is on understanding QCD, rather than testing it. The papers gathered in this special focus section of Journal of Physics G: Nuclear and Particle Physics attempt to cover this broad range of subjects. Alkofer and Greensite examine the issue of quark and gluon confinement with the focus on models of the QCD vacuum, lattice gauge theory investigations, and the relationship to the AdS/CFT correspondence postulate. Arrington et al. review nucleon form factors and their role in determining quark orbital momentum, the strangeness content of the nucleon, meson cloud effects, and the transition from nonperturbative to perturbative QCD dynamics. The physics associated with hadronic matter at high temperature and density and at low Bjorken-x at the Relativistic Heavy Ion Collider (RHIC), the SPS at CERN, and at the future LHC is summarized by d'Enterria. The article of Lee and Smith examines experiment and theory associated with electromagnetic meson production from nucleons and

Heavy flavour hadron spectroscopy: An overview

Indian Academy of Sciences (India)

2014-10-31

Oct 31, 2014 ... A comprehensive overview and some of the theoretical attempts towards understanding heavy flavour hadron spectroscopy are presented. Apart from the conventional quark structure (quark, antiquarks structure for the mesons and three-quarks structure of baryons) of hadrons, multiquark hadrons the ...

Multiplicities of secondary hadrons produced in vp and anti vp charged current interactions

International Nuclear Information System (INIS)

Graessler, H.; Lanske, D.; Schulte, R.; Chima, J.S.; Mobayyen, M.M.; Talebzadeh, M.; Villalobos-Baillie, O.; Corrigan, G.; Myatt, G.; Radojicic, D.; Saitta, B.; Wells, J.

1983-01-01

In an experiment with the hydrogen bubble chamber BEBC at CERN multiplicities of hadrons produced in vp and anti vp interactions have been investigated. Results are presented on the multiplicities of charged hadrons and neutral pions, forward and backward multiplicities of charged hadrons and correlations between forward and backward multiplicities. Comparisons are made with hadronic reactions and e + e - annihilation. In the framework of the quark-parton model the data imply similar charged multiplicities for the fragments of a u- and a d-quark, and larger multiplicities for the fragments of a uu- than for a ud-diquark. The correlation data suggest independent fragmentation of the quark and diquark for hadronic masses above approx.= 7 GeV and local charge compensation within an event. (orig.)

Hadron production at SPEAR

International Nuclear Information System (INIS)

Schwitters, R.F.

1975-01-01

A report is given of the knowledge obtained from SPEAR about hadron production in e + e - annihilation since the discovery of the new particles. Included are the SPEAR magnetic detector, the total cross sections, mean charged multiplicity and energy, inclusive momentum spectra, and hadron angular distribution

Analysis of soft wall AdS/QCD potentials to obtain the melting temperature of scalar hadrons

Energy Technology Data Exchange (ETDEWEB)

Vega, Alfredo; Ibanez, Adolfo [Universidad de Valparaiso, Instituto de Fisica y Astronomia, Valparaiso (Chile)

2017-11-15

We consider an analysis of potentials related to Schroedinger-type equations for scalar fields in a 5D AdS black hole background with dilaton in order to obtain melting temperatures for different hadrons in a thermal bath. The approach does not consider calculations of spectral functions, and it is easy to yield results for hadrons with an arbitrary number of constituents. We present results for scalar mesons, glueballs, hybrid mesons and tetraquarks, and we show that mesons are more resistant to being melted in a thermal bath than other scalar hadrons, and in general the melting temperature increases when hadrons contain heavy quarks. (orig.)

Experimental momentum spectra of identified hadrons in jets and the predictions from LPHD + MLLA

International Nuclear Information System (INIS)

Bruemmer, N.C.