Electromagnetic form factors of hadrons
Zidell, V.S.
1976-01-01
A vector meson dominance model of the electromagnetic form factors of hadrons is developed which is based on the use of unstable particle propagators. Least-square fits are made to the proton, neutron, pion and kaon form factor data in both the space and time-like regions. A good fit to the low-energy nucleon form factor data is obtained using only rho, ω, and phi dominance, and leads to a determination of the vector meson resonance parameters in good agreement with experiment. The nucleon-vector meson coupling constants obey simple sum rules indicating that there exists no hard core contribution to the form factors within theoretical uncertainties. The prediction for the electromagnetic radii of the proton is in reasonable agreement with recent experiments. The pion and kaon charge form factors as deduced from the nucleon form factors assuming vector meson universality are compared to the data. The pion form factor agrees with the data in both the space and time-like regions. The pion charge radius is in agreement with the recent Dubna result, but the isovector P-wave pion-pion phase shift calculated from the theory disagrees with experiment. A possible contribution to the form factors from a heavy rho meson is also evaluated
Electromagnetic Hadronic Form-Factors
Edwards, Robert G.
2005-01-01
We present a calculation of the nucleon electromagnetic form-factors as well as the pion and rho to pion transition form-factors in a hybrid calculation with domain wall valence quarks and improved staggered (Asqtad) sea quarks
Hadronic form factors in kaon photoproduction
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.
Zeros in the electromagnetic and hadronic form factors
Martini, A.F.; Menon, M.J.; Montanha, J.
2004-01-01
We discuss the evidences for the existence of zeros in the electric and in the hadronic form factors of the proton. We show that the shape of both form factors are similar, but there is indication that the hadronic form factors can depend on the energy. (author)
Hadron collisions and the fifth form factor
Dokshitzer, Yu.L.; Marchesini, G.
2005-01-01
Logarithmically enhanced effects due to radiation of soft gluons at large angles in 2->2 QCD scattering processes are treated in terms of the ''fifth form factor'' that accompanies the four collinear singular Sudakov form factors attached to incoming and outgoing hard partons. Unexpected symmetry under exchange of internal and external variables of the problem is pointed out for the anomalous dimension that governs soft gluon effects in hard gluon-gluon scattering
Covariance dynamics and symmetries, and hadron form factors
Bhagwat, M.S.; Cloet, I.C.; Roberts, C.D.
2007-01-01
We summarize applications of Dyson-Schwinger equations to the theory and phenomenology of hadrons. Some exact results for pseudoscalar mesons are highlighted with details relating to the U A (1) problem. We describe inferences from the gap equation relating to the radius of convergence for expansions of observables in the current-quark mass. We recapitulate upon studies of nucleon electromagnetic form factors, providing a comparison of the ln-weighted ratios of Pauli and Dirac form factors for the neutron and proton.
Form factors and structure functions of hadrons in parton model
Volkonskij, N.Yu.
1979-01-01
The hadron charge form factors and their relation to the deep-inelastic lepton-production structure functions in the regions of asymptotically high and small momentum transfer Q 2 are studied. The nucleon and pion charge radii are calculated. The results of calculations are in good agreement with the experimental data. The K- and D-meson charge radii are estimated. In the region of asymptotically high Q 2 the possibility of Drell-Yan-West relation violation is analyzed. It is shown, that for pseudoscalar mesons this relation is violated. The relation between the proton and neutron form factor asymptotics is obtained
Hadron form factors in the constituent quark model
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)
Microscopic models for hadronic form factors and vertex functions
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
Hadron spectroscopy and form factors at quark level
Chakrabarty, S.; Gupta, K.K.; Singh, N.N.; Mitra, A.N.
1988-01-01
The theoretical status of hadrons as quark composites is examined from the point of view of a simultaneous understanding of their on-shell (mass spectra) and off-shell (form factors, transition amplitudes) properties. Greater stress is laid on light quark systems which are more sensitive to the confinement regime, and more prone to relativistic effects than on heavy quarkonia (on which many reviews exist). Two broad theoretical approaches obeying Lorentz and gauge invariance are identified: (i) QCD sum rules as a means of extrapolation from high to low energies; and (ii) dynamical equations for providing a microcausal link in the opposite direction (from low to high energies). The latter represents the major focus of attention in this article, with the Bethe-Salpeter Equation (BSE) providing a formal plank for a comparative assessment of several models. The Null-plane ansatz which facilitates the reduction of the 4-D BSE to a covariant 3-D form also provides the language for its comparison with other covariant 3-D equations. In particular, attention is drawn to the interesting possibility of reconstructing the 4-D BS wave function from its 3-D form (in a two-tier fashion) as a practical tool for generating higher Fock-space components (qq effects) in the BS wave function, and (more interestingly) for a clean separation between soft and hard QCD effects. To illustrate one such practical tool for an integrated view of different hadronic sectors within a single framework, the results of a two-tier BS model are presented in respect of qq-bar, qqq, gg, ggg, gqq-bar states and compared with experiment as well as with the results of other contemporary models. The N.R Resonating Group Method, which becomes necessary for bigger (six-quark) systems is briefly discussed from the point of view of its compatibility with a relativistic form of quark dynamics motivated from the BSC. (Author)
Hadronic Form Factors in Asymptotically Free Field Theories
Gross, D. J.; Treiman, S. B.
1974-01-01
The breakdown of Bjorken scaling in asymptotically free gauge theories of the strong interactions is explored for its implications on the large q{sup 2} behavior of nucleon form factors. Duality arguments of Bloom and Gilman suggest a connection between the form factors and the threshold properties of the deep inelastic structure functions. The latter are addressed directly in an analysis of asymptotically free theories; and through the duality connection we are then led to statements about the form factors. For very large q{sup 2} the form factors are predicted to fall faster than any inverse power of q{sup 2}. For the more modest range of q{sup 2} reached in existing experiments the agreement with data is fairly good, though this may well be fortuitous. Extrapolations beyond this range are presented.
Electromagnetic Form Factors of Hadrons in Dual-Large Nc QCD
Dominguez, C. A.
2011-01-01
In this talk, results are presented of determinations of electromagnetic form factors of hadrons (pion, proton, and Δ(1236)) in the framework of Dual-Large N c QCD (Dual-QCD ∞ ). This framework improves considerably tree-level VMD results by incorporating an infinite number of zero-width resonances, with masses and couplings fixed by the dual-resonance (Veneziano-type) model.
Hadronic form factor models and spectroscopy within the gauge/gravity correspondence
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
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.
Relativistic form factors for hadrons with quark-model wave functions
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
Analysis tools for precision studies of hadronic three-body decays and transition form factors
Schneider, Sebastian Philipp
2013-01-01
Due to the running coupling constant of Quantum Chromodynamics one of the pillars of the Standard Model, the strong interactions, is still insufficiently understood at low energies. In order to describe the interactions of hadrons that form in this physical regime, one has to devise methods that are non-perturbative in the strong coupling constant. In particular hadronic three-body decays and transition form factors present a great challenge due to the complex analytic structure ensued by strong final-state interactions. In this thesis we present two approaches to tackle these processes. In the first part we use a modified version of non-relativistic effective field theory to analyze the decay η→3π. This perturbative low-energy expansion is ideally suited to study the effects of ππ rescattering and contributes greatly to the understanding of the slope parameter of the η→3π 0 Dalitz plot, a quantity that is strongly influenced by final-state interactions and has presented a long-standing puzzle for theoretical approaches. In the second part we present dispersion relations as a non-perturbative means to study three-particle decays. Using the example of η'→ηππ we give a detailed introduction to the framework and its numerical implementation. We confront our findings with recent experimental data from the BES-III and VES collaborations and discuss whether the extraction of πη scattering parameters, one of the prime motives to study this decay channel, is feasible in such an approach. A more clear-cut application is given in our study of the decays ω/φ→3π due to the relative simplicity of this decay channel: our results are solely dependent on the ππ P-wave scattering phase shift. We give predictions for the Dalitz plot distributions and compare our findings to very precise data on φ→3π by the KLOE and CMD-2 collaborations. We also predict Dalitz plot parameters that may be determined in future high-precision measurements of ω→3π and
Analysis tools for precision studies of hadronic three-body decays and transition form factors
Schneider, Sebastian Philipp
2013-02-14
Due to the running coupling constant of Quantum Chromodynamics one of the pillars of the Standard Model, the strong interactions, is still insufficiently understood at low energies. In order to describe the interactions of hadrons that form in this physical regime, one has to devise methods that are non-perturbative in the strong coupling constant. In particular hadronic three-body decays and transition form factors present a great challenge due to the complex analytic structure ensued by strong final-state interactions. In this thesis we present two approaches to tackle these processes. In the first part we use a modified version of non-relativistic effective field theory to analyze the decay {eta}{yields}3{pi}. This perturbative low-energy expansion is ideally suited to study the effects of {pi}{pi} rescattering and contributes greatly to the understanding of the slope parameter of the {eta}{yields}3{pi}{sup 0} Dalitz plot, a quantity that is strongly influenced by final-state interactions and has presented a long-standing puzzle for theoretical approaches. In the second part we present dispersion relations as a non-perturbative means to study three-particle decays. Using the example of {eta}'{yields}{eta}{pi}{pi} we give a detailed introduction to the framework and its numerical implementation. We confront our findings with recent experimental data from the BES-III and VES collaborations and discuss whether the extraction of {pi}{eta} scattering parameters, one of the prime motives to study this decay channel, is feasible in such an approach. A more clear-cut application is given in our study of the decays {omega}/{phi}{yields}3{pi} due to the relative simplicity of this decay channel: our results are solely dependent on the {pi}{pi} P-wave scattering phase shift. We give predictions for the Dalitz plot distributions and compare our findings to very precise data on {phi}{yields}3{pi} by the KLOE and CMD-2 collaborations. We also predict Dalitz plot
From Theory to Experiment: Hadron Electromagnetic Form Factors in Space-like and Time-like Regions
Tomasi-Gustafsson, E.; Gakh, G.I.; Rekalo, A.P.
2007-01-01
Hadron electromagnetic form factors contain information on the intrinsic structure of the hadrons. The pioneering work developed at the Kharkov Physical-Technical Institute in the 60's on the relation between the polarized cross section and the proton form factors triggered a number of experiments. Such experiments could be performed only recently due to the progress in accelerator and polarimetry techniques. The principle of these measurements is recalled and surprise and very precise results obtained on proton are presented. The actual status of nucleon electromagnetic form factors is reviewed, with special attention to the basic work done in Kharkov Physical-Technical Institute. This Paper is devoted to the memory of Prof. M.P. Rekalo
Electromagnetic mass differences of hadrons with SU(6)/sub W/ x O(3) couplings and form factors
Sood, S.; Mitra, A.N.
1976-01-01
A systematiUsing these for account of a few typical electromagnetic mass differences of hadrons (N, Σ; K, π) is presented within the framework provided by a broken-SU(6)/sub W/ x O(3) model of hadron couplings. The model, which has specified combinations of couplings of ''magnetic'' and ''charge'' origin, is characterized by the supermultiplet form factors at the hadron vertices. The parameters of these functions on the mass shell have been determined recently via a study of the decay widths of the resonances. By use of these form factors, suitably extended off the mass shell of the vector meson so as to render the calculations formally free from series and integral divergences, the coupling scheme is found to provide a reasonable description of the mass differences through the twin mechanisms of dominance of magnetic contribution over charge contribution and that of (L + 1) wave couplings over (L - 1). A formal connection of this approach with the more conventional dispersion-theoretic one can be established through the observation that the subtraction term (necessary for ΔI = 1 cases of mass differences) finds a close parallel to the couplings of magnetic origin (which have extra momentum dependence vis-a-vis the charge couplings) the magnetic couplings are thus made relatively more important for the ΔI = 1 cases according to Harari's interpretation. The model is not so successful for ΔI = 2 mass differences which are dominated by the (weaker) charge couplings
Remarks on electromagnetic form factors of hadrons in the quark model
Vainshtein, A.I.; Zakharov, V.I.
1977-01-01
Relations between the transversal and longitudinal parts of elastic and quasielastic form factors are studied within the quark model. It is shown that for an even number of the constituent quarks the longitudinal part dominates while for an odd number the transversal part is the largest one. Consequences form this result are considered for deuteron form factor and for matrix elements of the electromagnetic transitions between π, rho, A 1 mesons
About the damping of quark-hadron form factors in relative quark momentum
Lewin, K.; Kallies, W.
1979-01-01
A problem of sufficient damping of hadron bound states at nonasymptotic relative quark momenta is discussed. This phenomenon is considered in the connection with the power scaling beginning at momentum transfer | t | >= 2-3 GeV 2 . Damping of hadron bound states is obtained on the basis of a behaviour of four-quark Green's functions in the momentum transfer which is required by diffraction scattering
Dependence of electromagnetic form factors of hadrons on light-cone frames
Weber, H.J.; Xu Xiaoming; Chinese Acad. of Sci., Shanghai
1996-01-01
A constituent quark model is developed for an arbitrary light-cone direction so that the light-front time is x LF + =ω.x with a constant lightlike four-vector ω. Form factors are obtained from free one-body electromagnetic current matrix elements. They are found to be ω-independent for spin-0 mesons, nucleons and the Λ-hyperon, while there is an ω-dependence for spin-1 systems like the deuteron. (orig.)
Factorization for short distance hadron-hadron scattering
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.)
Measurement of the q2 Dependence of the Hadronic Form Factor in D0 to K- e+ nu_e Decays
Aubert, B.
2006-09-26
A preliminary measurement of the q{sup 2} dependence of the D{sup 0} {yields} K{sup -}e{sup +}{nu}{sub e} decay rate is presented. This rate is proportional to the hadronic form factor squared, specified by a single parameter. This is either the mass in the simple pole ansatz m{sub pole} = (1.854 {+-} 0.016 {+-} 0.020) GeV/c{sup 2} or the scale in the modified pole ansatz {alpha}{sub pole} = 0.43 {+-} 0.03 {+-} 0.04. The first error refers to the statistical, the second to the systematic uncertainty.
Scaling of nuclear modification factors for hadrons and light nuclei
Zhou, C.S. [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China); University of Chinese Academy of Sciences, Beijing (China); Ma, Y.G. [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China); ShanghaiTech University, Shanghai (China); Zhang, S. [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China)
2016-12-15
The number of constituent quarks (NCQ) scaling for hadrons and the number of constituent nucleons (NCN) scaling for light nuclei are proposed for nuclear modification factors (R{sub cp}) of hadrons and light nuclei, respectively, according to the experimental investigations in relativistic heavy-ion collisions. Based on the coalescence mechanism the scalings are performed for pions and protons at the quark level, and for light nuclei d(anti d) and {sup 3}He at the nucleonic level, respectively, formed in Au+Au and Pb+Pb collisions, and a nice scaling behaviour emerges. The NCQ or NCN scaling law of R{sub cp} can be, respectively, taken as a probe for the quark or nucleon coalescence mechanism for the formation of hadron or light nuclei in relativistic heavy-ion collisions. (orig.)
Singh, S.K.
2002-01-01
The present status of electroweak nucleon form factors and the N - Δ transition form factors is reviewed. Particularly the determination of dipole mass M A in the axial vector form factor is discussed
Strange mesonic transition form factor
Goity, J.L.; Musolf, M.J.
1996-01-01
The strange-quark vector current ρ-to-π meson transition form factor is computed at one-loop order using strange meson intermediate states. A comparison is made with a φ-meson dominance model estimate. We find that one-loop contributions are comparable in magnitude to those predicted by φ-meson dominance. It is possible that the one-loop contribution can make the matrix element as large as those of the electromagnetic current mediating vector meson radiative decays. However, due to the quadratic dependence of the one-loop results on the hadronic form factor cutoff mass, a large uncertainty in the estimate of the loops is unavoidable. These results indicate that non-nucleonic strange quarks could contribute appreciable in moderate-parallel Q 2 parallel parity-violating electron-nucleus scattering measurements aimed at probing the strange-quark content of the nucleon. copyright 1996 The American Physical Society
Frederic D. R. Bonnet; Robert G. Edwards; George T. Fleming; Randal Lewis; David Richards
2003-07-22
We have started a program to compute the electromagnetic form factors of mesons. We discuss the techniques used to compute the pion form factor and present preliminary results computed with domain wall valence fermions on MILC asqtad lattices, as well as Wilson fermions on quenched lattices. These methods can easily be extended to rho-to-gamma-pi transition form factors.
Neutron electromagnetic form factors
Finn, J.M.; Madey, R.; Eden, T.; Markowitz, P.; Rutt, P.M.; Beard, K.; Anderson, B.D.; Baldwin, A.R.; Keane, D.; Manley, D.M.; Watson, J.W.; Zhang, W.M.; Kowalski, S.; Bertozzi, W.; Dodson, G.; Farkhondeh, M.; Dow, K.; Korsch, W.; Tieger, D.; Turchinetz, W.; Weinstein, L.; Gross, F.; Mougey, J.; Ulmer, P.; Whitney, R.; Reichelt, T.; Chang, C.C.; Kelly, J.J.; Payerle, T.; Cameron, J.; Ni, B.; Spraker, M.; Barkhuff, D.; Lourie, R.; Verst, S.V.; Hyde-Wright, C.; Jiang, W.-D.; Flanders, B.; Pella, P.; Arenhoevel, H.
1992-01-01
Nucleon form factors provide fundamental input for nuclear structure and quark models. Current knowledge of neutron form factors, particularly the electric form factor of the neutron, is insufficient to meet these needs. Developments of high-duty-factor accelerators and polarization-transfer techniques permit new experiments that promise results with small sensitivities to nuclear models. We review the current status of the field, our own work at the MIT/Bates linear accelerator, and future experimental efforts
It! What is Soil? Chip Off the Old Block Soil Forming Factors Matters of Life and Death Underneath It All Wise Choices A World of Soils Soil Forming Factors 2 A Top to Bottom Guide 3 Making a Soil Monolith 4 Soil Orders 5 State Soil Monoliths 6 Where in the Soil World Are You? >> A Top to
Disconnected electromagnetic form factors
Wilcox, Walter
2001-01-01
Preliminary results of a calculation of disconnected nucleon electromagnetic factors factors on the lattice are presented. The implementation of the numerical subtraction scheme is outlined. A comparison of results for electric and magnetic disconnected form factors on two lattice sizes with those of the Kentucky group is presented. Unlike previous results, the results found in this calculation are consistent with zero in these sectors
Iso-vector form factors of the delta and nucleon in QCD sum rules
Ozpineci, A.
2012-01-01
Form factors are important non-perturbative properties of hadrons. They give information about the internal structure of the hadrons. In this work, iso-vector axial-vector and iso-vector tensor form factors of the nucleon and the iso-vector axial-vector Δ→N transition form factor calculations in QCD Sum Rules are presented.
Desplanques, B.
1987-01-01
Electromagnetic form factors, in first approximation, are sensitive to spatial distribution of nucleons and to their current. In second approximation, more precise effects are concerned, whose role is increasing with momentum transfer and participating essentially of short range nuclei description. They concern of course the nucleon-nucleon interaction while approaching each other and keeping their free-state identity, but also mutually polarizing one the other. In this last effect, radial and orbital excitations of nucleon, the nucleon mesonic cloud modification and the nucleon antinucleon pair excitation are included. In this paper, these contributions are discussed while trying to find the important elements for a good description of form factors. Current questions are also discussed. Light nuclei are essentially concerned [fr
Very rare, exclusive, hadronic decays in QCD factorization
König, Matthias
2016-01-01
We study exclusive hadronic decays of the electroweak bosons Z, W and h in the framework of QCD factorization. We show that the theory uncertainties in these channels are remarkably small compared to past applications of the QCD factorization framework. While the branching ratios are small, many of the modes are accessible at future colliders. The Higgs decays exhibit interesting dependences on the couplings due to the interferences of different diagram topologies, making the h → Vγ decays possible probes of the quark Yukawa couplings and the h → VZ decays probes of the coupling between the Higgs boson, a photon and a Z-boson.
Ryong Ji, C.; Pang, A.; Szczepaniak, A. [North Carolina State Univ., Raleigh, NC (United States)
1994-04-01
It is pointed out that the correct criterion to define the legal PQCD contribution to the exclusive processes in the lightcone perturbative expansion should be based on the large off-shellness of the lightcone energy in the intermediate states. In the lightcone perturbative QCD calculation of the pion form factor, the authors find that the legal PQCD contribution defined by the lightcone energy cut saturates in the smaller Q{sup 2} region compared to that defined by the gluon four-momentum square cut. This is due to the contribution by the highly off-energy-shell gluons in the end point regions of the phase space, indicating that the gluon four-momentum-square cut may have cut too much to define the legal PQCD.
Nucleon Electromagnetic Form Factors
Marc Vanderhaeghen; Charles Perdrisat; Vina Punjabi
2007-10-01
There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has greatly improved by performing double polarization experiments, in comparison with previous unpolarized data. Here we review the experimental data base in view of the new results for the proton, and neutron, obtained at JLab, MAMI, and MIT-Bates. The rapid evolution of phenomenological models triggered by these high-precision experiments will be discussed, including the recent progress in the determination of the valence quark generalized parton distributions of the nucleon, as well as the steady rate of improvements made in the lattice QCD calculations.
Chou-Yang model and PHI form factor
Fazal-e-Aleem; Saleem, M.; Rafique, M.
1988-03-01
By using the deduced differential cross-section data for PHIp elastic scattering at 175 GeV/c in the Chou-Yang model, the PHI form factor has been computed and parametrized. Then in conjunction with the proton form factor this form factor is used in the pristine Chou-Yang model to obtain differential cross-section data at Fermilab energies. The theoretical results agree with the experimental measurements, endorsing the conjecture that the hadronic form factor of neutral particle is proportional to its magnetic form factor.
Electromagnetic form factors at large momenta from lattice QCD
Chambers, A. J.; Dragos, J.; Horsley, R.; Nakamura, Y.; Perlt, H.; Pleiter, D.; Rakow, P. E. L.; Schierholz, G.; Schiller, A.; Somfleth, K.; Stüben, H.; Young, R. D.; Zanotti, J. M.; Qcdsf/Ukqcd/Cssm Collaborations
2017-12-01
Accessing hadronic form factors at large momentum transfers has traditionally presented a challenge for lattice QCD simulations. Here, we demonstrate how a novel implementation of the Feynman-Hellmann method can be employed to calculate hadronic form factors in lattice QCD at momenta much higher than previously accessible. Our simulations are performed on a single set of gauge configurations with three flavors of degenerate mass quarks corresponding to mπ≈470 MeV . We are able to determine the electromagnetic form factors of the pion and nucleon up to approximately 6 GeV2 , with results for the ratio of the electric and magnetic form factors of the proton at our simulated quark mass agreeing well with experimental results.
arXiv Isothermal compressibility of hadronic matter formed in relativistic nuclear collisions
Mukherjee, Maitreyee; Chatterjee, Arghya; Chatterjee, Sandeep; Adhya, Souvik Priyam; Thakur, Sanchari; Nayak, Tapan K.
We present the first estimates of isothermal compressibility (\\kT) of hadronic matter formed in relativistic nuclear collisions (\\sNN=7.7~GeV to 2.76~TeV) using experimentally observed quantities. \\kT~is related to the fluctuation in particle multiplicity, temperature and volume of the system formed in the collisions. Multiplicity fluctuations are obtained from the event-by-event distributions of charged particle multiplicities in narrow centrality bins. The dynamical components of the fluctuations are extracted by removing the contributions to the fluctuations from the number of participating nucleons. From the available experimental data, a constant value of \\kT~has been observed as a function of collision energy. The results are compared with calculations from UrQMD, AMPT and EPOS event generators, and estimations of \\kT~are made for Pb-Pb collisions at the CERN Large Hadron Collider. A hadron resonance gas (HRG) model has been used to calculate \\kT~as a function of collision energy. Our results show a dec...
Electromagnetic form factors at large momenta from lattice QCD
Chambers, Alexander J.; Dragos, J.; Michigan State Univ., East Lansing, MI; Horsley, R.
2017-01-01
Accessing hadronic form factors at large momentum transfers has traditionally presented a challenge for lattice QCD simulations. Here we demonstrate how a novel implementation of the Feynman-Hellmann method can be employed to calculate hadronic form factors in lattice QCD at momenta much higher than previously accessible. Our simulations are performed on a single set of gauge configurations with three flavours of degenerate mass quarks corresponding to m_π∼470 MeV. We are able to determine the electromagnetic form factors of the pion and nucleon up to approximately 6 GeV"2, with results for G_E/G_M in the proton agreeing well with experimental results.
Baryon electromagnetic form factors at BESIII
Dbeyssi Alaa
2017-01-01
Full Text Available Electromagnetic form factors are fundamental quantities which parameterize the electric and magnetic structure of hadrons. This contribution reports on the measurements of baryon electromagnetic form factors at the BESIII experiment in Beijing. The Beijing e+e− collider BEPCII is a double-ring symmetric collider running at √s between 2.0 and 4.6 GeV. Baryon electromagnetic form factors can be measured at BESIII in direct e+e−-annihilation and in initial state radiation processes. Based on the data collected by the BESIII detector at 12 center of mass energies between 2.23 and 3.67 GeV, the e+e− → p̄p cross section and the time-like proton form factor is measured. Preliminary results from the analysis of the initial state radiation process e+e− → p̄pγ using a data set of 7.408 fb−1 collected at center-of-mass energies between 3.773 and 4.6 GeV, are also presented. The cross section for e+e−→Λ¯Λ${e^ + }{e^ - } \\to \\bar \\Lambda \\Lambda $ is measured based on 40.5 pb−1 data collected at 4 energy points from the threshold up to 3.08 GeV. Preliminary results on the total cross section and the Λ effective form factor are shown. Ongoing analysis based on the high luminosity energy scan from 2015 and from radiative return at different √s are also described.
Calculation of pion form factor
Vahedi, N.; Amirarjomand, S.
1975-09-01
The pion form factor is calculated using the structure function Wsub(2), which incorporates kinematical constraints, threshold behaviour and scaling. The Bloom-Gilman sum rule is used and only the two leading Regge trajectories are taken into account
Helium Compton Form Factor Measurements at CLAS
Voutier, Eric J.-M. [Laboratoire de Physique Subatomique et Cosmologie
2013-07-01
The distribution of the parton content of nuclei, as encoded via the generalized parton distributions (GPDs), can be accessed via the deeply virtual Compton scattering (DVCS) process contributing to the cross section for leptoproduction of real photons. Similarly to the scattering of light by a material, DVCS provides information about the dynamics and the spatial structure of hadrons. The sensitivity of this process to the lepton beam polarization allows to single-out the DVCS amplitude in terms of Compton form factors that contain GPDs information. The beam spin asymmetry of the $^4$He($\\vec {\\mathrm e}$,e$' \\gamma ^4$He) process was measured in the experimental Hall B of the Jefferson Laboratory to extract the real and imaginary parts of the twist-2 Compton form factor of the $^4$He nucleus. The experimental results reported here demonstrate the relevance of this method for such a goal, and suggest the dominance of the Bethe-Heitler amplitude to the unpolarized process in the kinematic range explored by the experiment.
Nucleon structure functions, resonance form factors, and duality
Davidovsky, V.V.; Struminsky, B.V.
2003-01-01
The behavior of nucleon structure functions in the resonance region is explored. For form factors that describe resonance production, expressions are obtained that are dependent on the photon virtuality Q 2 , which have a correct threshold behavior, and which take into account available experimental data on resonance decay. Resonance contributions to nucleon structure functions are calculated. The resulting expressions are used to investigate quark-hadron duality in electron-nucleon scattering by taking the example of the structure function F 2
TRASYS form factor matrix normalization
Tsuyuki, Glenn T.
1992-01-01
A method has been developed for adjusting a TRASYS enclosure form factor matrix to unity. This approach is not limited to closed geometries, and in fact, it is primarily intended for use with open geometries. The purpose of this approach is to prevent optimistic form factors to space. In this method, nodal form factor sums are calculated within 0.05 of unity using TRASYS, although deviations as large as 0.10 may be acceptable, and then, a process is employed to distribute the difference amongst the nodes. A specific example has been analyzed with this method, and a comparison was performed with a standard approach for calculating radiation conductors. In this comparison, hot and cold case temperatures were determined. Exterior nodes exhibited temperature differences as large as 7 C and 3 C for the hot and cold cases, respectively when compared with the standard approach, while interior nodes demonstrated temperature differences from 0 C to 5 C. These results indicate that temperature predictions can be artificially biased if the form factor computation error is lumped into the individual form factors to space.
Form factors and QCD in spacelike and timelike region
A.P. Bakulev; A.V. Radyushkin; N.G. Stefanis
2000-01-01
The authors analyze the basic hard exclusive processes: πγ * γ-transition, pion and nucleon electromagnetic form factors, and discuss the analytic continuation of QCD formulas from the spacelike q 2 2 > 0 of the relevant momentum transfers. They describe the construction of the timelike version of the coupling constant α s . They show that due to the analytic continuation of the collinear logarithms each eigenfunction of the evolution equation acquires a phase factor and investigate the resulting interference effects which are shown to be very small. They found no sources for the K-factor-type enhancements in the perturbative QCD contribution to the hadronic form factors. To study the soft part of the pion electromagnetic form factor, they use a QCD sum rule inspired model and show that there are non-canceling Sudakov double logarithms which result in a K-factor-type enhancement in the timelike region
Form factors and QCD in spacelike and timelike regions
Bakulev, A. P.; Radyushkin, A. V.; Stefanis, N. G.
2000-01-01
We analyze the basic hard exclusive processes, the πγ * γ-transition and the pion and nucleon electromagnetic form factors, and discuss the analytic continuation of QCD formulas from the spacelike q 2 2 >0 of the relevant momentum transfers. We describe the construction of the timelike version of the coupling constant α s . We show that due to the analytic continuation of the collinear logarithms, each eigenfunction of the evolution equation acquires a phase factor and investigate the resulting interference effects which are shown to be very small. We find no sources for the K-factor-type enhancements in the perturbative QCD contribution to the hadronic form factors. To study the soft part of the pion electromagnetic form factor, we use a QCD sum rule inspired model and show that there are noncanceling Sudakov double logarithms which result in a K-factor-type enhancement in the timelike region
Dispersive analysis of the pion transition form factor
Hoferichter, M.; Kubis, B.; Leupold, S.; Niecknig, F.; Schneider, S. P.
2014-11-01
We analyze the pion transition form factor using dispersion theory. We calculate the singly-virtual form factor in the time-like region based on data for the cross section, generalizing previous studies on decays and scattering, and verify our result by comparing to data. We perform the analytic continuation to the space-like region, predicting the poorly-constrained space-like transition form factor below , and extract the slope of the form factor at vanishing momentum transfer . We derive the dispersive formalism necessary for the extension of these results to the doubly-virtual case, as required for the pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.
Meson Form Factors and Deep Exclusive Meson Production Experiments
Horn, Tanja [The Catholic Univ. of America, Washington, DC (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2017-05-01
Pion and kaon electroproduction data play a unique role in Nature and our understanding of them is essential for explaining hadron structure. Precision longitudinaltransverse separated pion and kaon cross sections are of particular interest. They allow for the extraction of meson form factors and validation of understanding of hard exclusive and semi-inclusive reactions (π+, K+, π0, γ) towards 3D hadron imaging and potential future flavor decomposition. We review recent data and present prospects for deep exclusive pion and kaon electroproduction at the 12 GeV Jefferson Lab including the prospects to use projected charged- and neutral pion data to further determine the spin, charge-parity and flavor of GPDs, including the helicity-flip GPDs.
Helicity non-conserving form factor of the proton
Voutier, E.; Furget, C.; Knox, S. [Universite Joseph Fourier, Grenoble (France)] [and others
1994-04-01
The study of the hadron structure in the high Q{sup 2} range contributes to the understanding of the mechanisms responsible for the confinement of quarks and gluons. Among the numerous experimental candidates sensitive to these mechanisms, the helicity non-conserving form factor of the proton is a privileged observable since it is controlled by non-perturbative effects. The authors investigate here the feasibility of high Q{sup 2} measurements of this form factor by means of the recoil polarization method in the context of the CEBAF 8 GeV facility. For that purpose, they discuss the development of a high energy proton polarimeter, based on the H({rvec p},pp) elastic scattering, to be placed at the focal plane of a new hadron spectrometer. It is shown that this experimental method significantly improves the knowledge of the helicity non-conserving form factor of the proton up to 10 GeV{sup 2}/c{sup 2}.
Factorization and pion form factor in QCD
Efremov, A.V.; Radyushkin, A.V.
1979-01-01
The behaviour of the pion electromagnetic form factor (EMFF) in the framework of quantum chromodynamics (QCD) is discussed. Pion is considered to be a quark-antiquark bound state. It is proposed to use an OPE description of the bound state structure by matrix elements of certain local gauge-invariant operators. Short-distance quark interactions is proved using a direct analysis of perturbation theory in the α-parametric representation of the Feynman diagrams. It is shown that the short-distance parton picture privides a self-consistent description of the large Q 2 momentum behaviour of the pion EMFF in QCD. Pion EMFF asymptotics is expressed in terms of fu fundamental constants of the theory
CEBAF at higher energies and the kaon electromagnetic form factor
Baker, O.K.
1994-04-01
The electromagnetic production of strangeness, the physics of exciting systems having strangeness degrees of freedom (production of hadrons with one or more strange constituent quarks) using electromagnetic probes (real or virtual photons), is one of the frontier areas of research which will be investigated at the Continuous Electron Beam Accelerator Facility (CEBAF) when it becomes operational. CEBAF is expected to have an important impact upon this field of research using its specialized set of detection instruments and high quality electron beam. This paper focusses upon one aspect of the associated production of strangeness - the determination of the kaon electromagnetic form factor at high squared momentum transfers.
Electroweak form factors of the Skyrmion
Braaten, E.; Sze-Man Tse; Willcox, C.
1986-01-01
The electroweak form factors of baryons are studied in the semiclassical approximation to the Skyrme model. General expressions for the form factors are given for arbitrary choices of the Skyrme-model Lagrangian. They are applied to the original two-parameter Skyrme model to compute the electric, magnetic, and axial-vector form factors of the nucleon and the electromagnetic nucleon-Δ transition form factors. The dependence of the form factors on the momentum transfer is compared with phenomenological dipole parametrizations
Revisiting charmless hadronic Bu,d decays in QCD factorization
Cheng, H.-Y.; Chua, C.-K.
2009-01-01
Within the framework of QCD factorization, we consider two different types of power correction effects in order to resolve the CP puzzles and rate deficit problems with penguin-dominated two-body decays of B mesons and color-suppressed tree-dominated π 0 π 0 and ρ 0 π 0 modes: penguin annihilation and soft corrections to the color-suppressed tree amplitude. We emphasize that the electroweak penguin solution to the B→Kπ CP puzzle via new physics is irrelevant for solving the CP and rate puzzles related to tree-dominated decays. While some channels, e.g. K - π + , K - ρ 0 , π + π - , ρ ± π ± need penguin annihilation to induce the correct magnitudes and signs for their CP violation, some other decays such as B - →K - π 0 , π - η, K - η and B 0 →K* 0 η, π 0 π 0 require the presence of both power corrections to account for the measured CP asymmetries. In general, QCD factorization predictions for the branching fractions and direct CP asymmetries of B→PP, VP, VV decays are in good agreement with experiment. The predictions of perturbative QCD and soft-collinear effective theory are included for comparison.
Quark charge retention in final state hadrons form deep inelastic muon scattering
Albanese, J.P.; Blum, D.; Heusse, P.; Jaffre, M.; Jacholkowska, A.; Pascaud, C.; Carr, J.; Chima, J.S.; Clifft, R.; Edwards, M.; Norton, P.R.; Oakham, F.G.; Thompson, J.C.; Figiel, J.; Hoppe, C.; Janata, F.; Preissner, H.; Rondio, E.; Studt, M.; La Torre, A. de; Dengler, F.; Derado, I.; Eckardt, V.; Manz, A.; Schmitz, N.; Shiers, J.; Wolf, G.; Arneodo, M.; Arvidson, A.; Aubert, J.J.; Becks, K.H.; Bee, C.; Benchouk, C.; Bird, I.; Boehm, E.; Braun, H.; Brown, S.; Brueck, H.; Calen, H.; Callebaut, D.; Cobb, J.H.; Combley, F.; Coughlan, J.; Court, G.R.; D'Agostini, G.; Dahlgren, S.; Davies, J.K.; Dau, W.D.; Dreyer, T.; Drees, J.; Dumont, J.J.; Dueren, M.; Edwards, A.; Ernst, T.; Ferrero, M.I.; Foster, J.; Gamet, R.; Geddes, N.; Giubellino, P.; Grafstroem, P.; Grard, F.; Gustafsson, L.; Haas, J.; Hagberg, E.; Hasert, F.J.; Hayman, P.; Johnson, A.S.; Kabuss, E.M.; Krueger, J.; Kullander, S.; Landgraf, U.; Lanske, D.; Loken, J.; Long, K.; Mohr, W.; Montanet, F.; Mount, R.P.; Paul, L.; Payre, P.; Peroni, C.; Pettingale, J.; Poetsch, M.; Renton, P.; Rith, K.; Schlagboehmer, A.; Schroeder, T.; Schultze, K.; Sloan, T.; Stier, H.E.; Stockhausen, W.; Taylor, G.; Wahlen, H.; Wallucks, W.; Whalley, M.; Williams, W.S.C.; Wheeler, S.; Wimpenny, S.; Windmolders, R.
1984-01-01
The net charge of final state hadrons in both the current and target fragmentation regions has been measured in a 280 GeV/c muon-proton scattering experiment. A clean kinematic separation of the two regions in the centre-of-mass rapidity is demonstrated. The dependence on chisub(Bj) of the mean net charges is found to be consistent with a large contribution of sea quarks at small chisub(Bj) and with the dominance of valence quarks at large chisub(Bj) thus giving clear confirmation of the quark-parton model. It is also shown that the leading forward hadron has a high probability of containing the struck quark. (orig.)
Atti, C. Ciofi degli; Pace, E.; Salmé, G.
1993-01-01
The theory of inclusive lepton scattering of polarized leptons by polarized J = 1/2 hadrons is presented and the origin of different expressions for the polarized nuclear response function appearing in the literature is explained. The sensitivity of the longitudinal asymmetry upon the neutron form factors is investigated.
Proton and neutron charge form factors in soliton model with dilaton-quarkonium fields
Magar, E.N.; Nikolaev, V.A.; Tkachev, O.G.; Novozhilov, V.Yu.
1997-01-01
Nucleon electromagnetic form factors are considered in the framework of the generalized Skyrme model with dilaton-quarkonium fields. In our first publication we got big discrepancy between calculated form factors and dipole approximation formula. Here we have reasonably good accordance between them in finite impulse region after vector meson dominance has been taken into account. Omega- and rho-mesons have been included only into hadron structure of the photon
Dispersive analysis of the pion transition form factor
Hoferichter, M. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, ExtreMe Matter Institute EMMI, Darmstadt (Germany); University of Bern, Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, Bern (Switzerland); Kubis, B.; Niecknig, F.; Schneider, S.P. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Bonn (Germany); Leupold, S. [Uppsala Universitet, Institutionen foer fysik och astronomi, Box 516, Uppsala (Sweden)
2014-11-15
We analyze the pion transition form factor using dispersion theory. We calculate the singly-virtual form factor in the time-like region based on data for the e{sup +}e{sup -} → 3π cross section, generalizing previous studies on ω, φ → 3π decays and γπ → ππ scattering, and verify our result by comparing to e{sup +}e{sup -} → π{sup 0}γ data. We perform the analytic continuation to the space-like region, predicting the poorlyconstrained space-like transition form factor below 1 GeV, and extract the slope of the form factor at vanishing momentum transfer a{sub π} = (30.7 ± 0.6) x 10{sup -3}. We derive the dispersive formalism necessary for the extension of these results to the doubly-virtual case, as required for the pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon. (orig.)
On form factors of boundary changing operators
Bajnok, Z., E-mail: bajnok.zoltan@wigner.mta.hu [MTA Lendület Holographic QFT Group, Wigner Research Centre for Physics, P.O.B. 49, H-1525 Budapest 114 (Hungary); Hollo, L., E-mail: hollo.laszlo@wigner.mta.hu [MTA Lendület Holographic QFT Group, Wigner Research Centre for Physics, P.O.B. 49, H-1525 Budapest 114 (Hungary); Laboratoire de Physique Théorique, École Normale Supérieure, 24, rue Lhomond, 75005 Paris (France)
2016-04-15
We develop a form factor bootstrap program to determine the matrix elements of local, boundary condition changing operators. We propose axioms for these form factors and determine their solutions in the free boson and Lee–Yang models. The sudden change in the boundary condition, caused by an operator insertion, can be interpreted as a local quench and the form factors provide the overlap of any state before the quench with any outgoing state after the quench.
Perturbative corrections to B → D form factors in QCD
Wang, Yu-Ming; Wei, Yan-Bing; Shen, Yue-Long; Lü, Cai-Dian
2017-06-01
We compute perturbative QCD corrections to B → D form factors at leading power in Λ/ m b , at large hadronic recoil, from the light-cone sum rules (LCSR) with B-meson distribution amplitudes in HQET. QCD factorization for the vacuum-to- B-meson correlation function with an interpolating current for the D-meson is demonstrated explicitly at one loop with the power counting scheme {m}_c˜ O(√{Λ {m}_b}) . The jet functions encoding information of the hard-collinear dynamics in the above-mentioned correlation function are complicated by the appearance of an additional hard-collinear scale m c , compared to the counterparts entering the factorization formula of the vacuum-to- B-meson correction function for the construction of B → π from factors. Inspecting the next-to-leading-logarithmic sum rules for the form factors of B → Dℓν indicates that perturbative corrections to the hard-collinear functions are more profound than that for the hard functions, with the default theory inputs, in the physical kinematic region. We further compute the subleading power correction induced by the three-particle quark-gluon distribution amplitudes of the B-meson at tree level employing the background gluon field approach. The LCSR predictions for the semileptonic B → Dℓν form factors are then extrapolated to the entire kinematic region with the z-series parametrization. Phenomenological implications of our determinations for the form factors f BD +,0 ( q 2) are explored by investigating the (differential) branching fractions and the R( D) ratio of B → Dℓν and by determining the CKM matrix element |V cb | from the total decay rate of B → Dμν μ .
Charge-symmetry-breaking nucleon form factors
Kubis, Bastian, E-mail: kubis@hiskp.uni-bonn.de [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics (Germany)
2011-11-15
A quantitative understanding of charge-symmetry breaking is an increasingly important ingredient for the extraction of the nucleon's strange vector form factors. We review the theoretical understanding of the charge-symmetry-breaking form factors, both for single nucleons and for {sup 4}He.
Charge-symmetry-breaking nucleon form factors
Kubis, Bastian
2011-01-01
A quantitative understanding of charge-symmetry breaking is an increasingly important ingredient for the extraction of the nucleon’s strange vector form factors. We review the theoretical understanding of the charge-symmetry-breaking form factors, both for single nucleons and for 4 He.
Calculation of nucleon electromagnetic form factors
Renner, D.B.; Brower, R.; Dolgov, D.; Eicker, N.; Lippert, Th.; Negele, J.W.; Pochinsky, A.; Schilling, K.
2003-01-01
The formalism is developed to express nucleon matrix elements of the electromagnetic current in terms of form factors consistent with the translational, rotational, and parity symmetries of a cubic lattice. We calculate the number of these form factors and show how appropriate linear combinations approach the continuum limit
Proton electromagnetic form factors: Basic notions, present achievements and future perspectives
Pacetti, Simone, E-mail: simone.pacetti@pg.infn.it [Dipartimento di Fisica e Geologia dell’Universitá degli Studi di Perugia and INFN Sezione di Perugia, 06123 Perugia (Italy); Baldini Ferroli, Rinaldo [INFN, Laboratori Nazionali di Frascati, 00044 Frascati (Italy); Tomasi-Gustafsson, Egle [CEA, IRFU, SPhN, Saclay, 91191 Gif-sur-Yvette Cedex (France); CNRS/IN2P3, Institut de Physique Nucléaire, UMR 8608, 91406 Orsay (France)
2015-01-20
The aim of this report is to give basic notions on electromagnetic hadron form factors (FFs), as they are understood at the present time, to summarize and analyze the present experimental results and available theoretical models and to open a view on future perspectives. FFs are fundamental quantities, which describe the internal, dynamical structure of hadrons. Although the theoretical formalism was settled in the middle of last century, as well as the first experiments in electron–proton elastic scattering for which R. Hofstadter got the Nobel prize in 1961, a renewed activity is due to recent, surprising results and to the opening of new experimental possibilities. An elegant formalism was built on the assumption of a hadron electromagnetic interaction based on the exchange of a virtual photon of four-momentum q{sup 2}. In this case FFs are analytic functions of only one variable, q{sup 2}, and the electromagnetic vertex γ{sup ∗}hh (h is any hadron) is defined by two structure functions, which, in turn, are expressed in terms of (2S+1) FFs, S being the hadron spin, assuming parity and time-invariance. Our aim is to anticipate the potentiality contained in the future data, combined with the present knowledge, to point out the relevant observables and the most significative measurements, and to give predictions to be compared to the data when they will be available.
Proton electromagnetic form factors: Basic notions, present achievements and future perspectives
Pacetti, Simone; Baldini Ferroli, Rinaldo; Tomasi-Gustafsson, Egle
2015-01-01
The aim of this report is to give basic notions on electromagnetic hadron form factors (FFs), as they are understood at the present time, to summarize and analyze the present experimental results and available theoretical models and to open a view on future perspectives. FFs are fundamental quantities, which describe the internal, dynamical structure of hadrons. Although the theoretical formalism was settled in the middle of last century, as well as the first experiments in electron–proton elastic scattering for which R. Hofstadter got the Nobel prize in 1961, a renewed activity is due to recent, surprising results and to the opening of new experimental possibilities. An elegant formalism was built on the assumption of a hadron electromagnetic interaction based on the exchange of a virtual photon of four-momentum q 2 . In this case FFs are analytic functions of only one variable, q 2 , and the electromagnetic vertex γ ∗ hh (h is any hadron) is defined by two structure functions, which, in turn, are expressed in terms of (2S+1) FFs, S being the hadron spin, assuming parity and time-invariance. Our aim is to anticipate the potentiality contained in the future data, combined with the present knowledge, to point out the relevant observables and the most significative measurements, and to give predictions to be compared to the data when they will be available
Electromagnetic form factors of a massive neutrino
Dvornikov, M.S.; Studenikin, A.I.
2004-01-01
Electromagnetic form factors of a massive neutrino are studied in a minimally extended standard model in an arbitrary R ξ gauge and taking into account the dependence on the masses of all interacting particles. The contribution from all Feynman diagrams to the electric, magnetic, and anapole form factors, in which the dependence of the masses of all particles as well as on gauge parameters is accounted for exactly, are obtained for the first time in explicit form. The asymptotic behavior of the magnetic form factor for large negative squares of the momentum of an external photon is analyzed and the expression for the anapole moment of a massive neutrino is derived. The results are generalized to the case of mixing between various flavors of the neutrino. Explicit expressions are obtained for the electric, magnetic, and electric dipole and anapole transitional form factors as well as for the transitional electric dipole moment
The pion form factor from first principles
Heide, J. van der
2004-01-01
We calculate the electromagnetic form factor of the pion in quenched lattice QCD. The non-perturbatively improved Sheikoleslami-Wohlert lattice action is used together with the O(a) improved current. We calculate form factor for pion masses down to mπ = 380 MeV. We compare the mean square radius for the pion extracted from our form factors to the value obtained from the 'Bethe Salpeter amplitude'. Using (quenched) chiral perturbation theory, we extrapolate our results towards the physical pion mass
Measurement of the pion form factor
Dally, E.; Hauptman, J.; May, C.
1977-01-01
The pion form factor has been measured in the momentum transfer range of 0.03( 2 by scattering pions from atomic electrons in a liquid hydrogen target. The pion form factor is defined to be the elastic scattering cross section divided by that predicted for a point pion. The experiment has been performed in a 100 GeV/c negative pion beam incident on a 50 cm liquid hydrogen target at Fermi laboratory. The corrected form factor equals 0.33+-0.06 f 2 . Vector dominance predicts 0.40 f 2
Small Form Factor RFID Applicator, Phase I
National Aeronautics and Space Administration — The proposed development of a small form factor Astrobee dedicated RFID label applicator will allow current and future free flying vehicles to place RFID labels...
Heavy meson form factors from QCD
Falk, A.F.; Georgi, H.; Grinstein, B.
1990-01-01
We calculate the leading QCD radiative corrections to the relations which follow from the decoupling of the heavy quark spin as the quark mass goes infinity and from the symmetry between systems with different heavy quarks. One of the effects we calculate gives the leading q 2 -dependence of the form factor of a heavy quark, which in turn dominates the q 2 -dependence of the form factors of bound states of the heavy quark with light quarks. This, combined with the normalization of the form factor provided by symmetry, gives us a first principles calculation of the heavy meson (or baryon) form factors in the limit of very large heavy quark mass. (orig.)
Make Projects Small Form Factor PCs
Wessels, Duane
2006-01-01
Shoebox sized and smaller, small-form-factor PCs can pack as much computing muscle as a full-sized desktop computer. They consumer less power, have few or no moving parts, and are very quiet. Whether you plan to use one as a standalone PC or want to embed it in your next hacking project, a small-form-factor PC can be a lot of fun to build. Make Projects: Small Form Factor PCs is the only book available that shows you how to build small-form-factor PCs -- from kits and from scratch -- that are more interesting and more personalized than what a full-sized PC can give you. Included in the book
Parallel Integer Factorization Using Quadratic Forms
McMath, Stephen S
2005-01-01
.... In 1975, Daniel Shanks used class group infrastructure to modify the Morrison-Brillhart algorithm and develop Square Forms Factorization, but he never published his work on this algorithm or provided...
Hadronic vacuum polarization and the test of quantum electrodynamics at low energies
Gerdt, V.P.; Faustov, R.N.; Karimkhodzhaev, A.
1978-01-01
A hadronic vacuum polarization correction to the photon propagator is found by using the Dubnicka-Meshcheryakov parametrization of the pion electromagnetic form factor and new experimental data on the e + e - hadrons annihilation cross section. The contribution from the hadronic vacuum polarization to the muon anomalous magnetic moment and the Lamb shift in muonic atoms are calculated
Meson Transition Form Factors in Light-Front Holographic QCD
Brodsky, Stanley J.; /SLAC; Cao, Fu-Guang; /Massey U.; de Teramond, Guy F.; /Costa Rica U.
2011-06-22
We study the photon-to-meson transition form factors (TFFs) F{sub M{gamma}}(Q{sup 2}) for {gamma}{gamma}* {yields} M using light-front holographic methods. The Chern-Simons action, which is a natural form in 5-dimensional anti-de Sitter (AdS) space, leads directly to an expression for the photon-to-pion TFF for a class of confining models. Remarkably, the predicted pion TFF is identical to the leading order QCD result where the distribution amplitude has asymptotic form. The Chern-Simons form is local in AdS space and is thus somewhat limited in its predictability. It only retains the q{bar q} component of the pion wavefunction, and further, it projects out only the asymptotic form of the meson distribution amplitude. It is found that in order to describe simultaneously the decay process {pi}{sup 0} {yields} {gamma}{gamma} and the pion TFF at the asymptotic limit, a probability for the q{bar q} component of the pion wavefunction P{sub q{bar q}} = 0.5 is required; thus giving indication that the contributions from higher Fock states in the pion light-front wavefunction need to be included in the analysis. The probability for the Fock state containing four quarks (anti-quarks) which follows from analyzing the hadron matrix elements, P{sub q{bar q}q{bar q}} {approx} 10%, agrees with the analysis of the pion elastic form factor using light-front holography including higher Fock components in the pion wavefunction. The results for the TFFs for the {eta} and {eta}{prime} mesons are also presented. The rapid growth of the pion TFF exhibited by the BABAR data at high Q{sup 2} is not compatible with the models discussed in this article, whereas the theoretical calculations are in agreement with the experimental data for the {eta} and {eta}{prime} TFFs.
Measurement of the $\\Lambda_{b}^{0}$ Decay Form Factor
Abdallah, J; Adam, W; Adzic, P; Albrecht, T; Alderweireld, T; Alemany-Fernandez, R; Allmendinger, T; Allport, P P; Amaldi, Ugo; Amapane, N; Amato, S; Anashkin, E; Andreazza, A; Andringa, S; Anjos, N; Antilogus, P; Apel, W D; Arnoud, Y; Ask, S; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Ballestrero, A; Bambade, P; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Ben-Haim, E; Benekos, N C; Benvenuti, Alberto C; Bérat, C; Berggren, M; Berntzon, L; Bertrand, D; Besançon, M; Besson, N; Bloch, D; Blom, M; Bluj, M; Bonesini, M; Boonekamp, M; Booth, P S L; Borisov, G; Botner, O; Bouquet, B; Bowcock, T J V; Boyko, I; Bracko, M; Brenner, R; Brodet, E; Brückman, P; Brunet, J M; Bugge, L; Buschmann, P; Calvi, M; Camporesi, T; Canale, V; Carena, F; Castro, N; Cavallo, F R; Chapkin, M M; Charpentier, P; Checchia, P; Chierici, R; Shlyapnikov, P; Chudoba, J; Chung, S U; Cieslik, K; Collins, P; Contri, R; Cosme, G; Cossutti, F; Costa, M J; Crawley, B; Crennell, D J; Cuevas-Maestro, J; D'Hondt, J; Dalmau, J; Da Silva, T; Da Silva, W; Della Ricca, G; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Maria, N; De Min, A; De Paula, L S; Di Ciaccio, Lucia; Di Simone, A; Doroba, K; Drees, J; Dris, M; Eigen, G; Ekelöf, T J C; Ellert, M; Elsing, M; Espirito-Santo, M C; Fanourakis, G K; Fassouliotis, D; Feindt, M; Fernández, J; Ferrer, A; Ferro, F; Flagmeyer, U; Föth, H; Fokitis, E; Fulda-Quenzer, F; Fuster, J A; Gandelman, M; García, C; Gavillet, P; Gazis, E N; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; Graziani, E; Grosdidier, G; Grzelak, K; Guy, J; Haag, C; Hallgren, A; Hamacher, K; Hamilton, K; Haug, S; Hauler, F; Hedberg, V; Hennecke, M; Herr, H; Hoffman, J; Holmgren, S O; Holt, P J; Houlden, M A; Hultqvist, K; Jackson, J N; Jarlskog, G; Jarry, P; Jeans, D; Johansson, E K; Johansson, P D; Jonsson, P; Joram, C; Jungermann, L; Kapusta, F; Katsanevas, S; Katsoufis, E C; Kernel, G; Kersevan, Borut P; Kerzel, U; Kiiskinen, A P; King, B T; Kjaer, N J; Kluit, P; Kokkinias, P; Kourkoumelis, C; Kuznetsov, O; Krumshtein, Z; Kucharczyk, M; Lamsa, J; Leder, G; Ledroit, F; Leinonen, L; Leitner, R; Lemonne, J; Lepeltier, V; Lesiak, T; Liebig, W; Liko, D; Lipniacka, A; Lopes, J H; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J; Malek, A; Maltezos, S; Mandl, F; Marco, J; Marco, R; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Mazzucato, F; Mazzucato, M; McNulty, R; Meroni, C; Meyer, W T; Myagkov, A; Migliore, E; Mitaroff, W A; Mjörnmark, U; Moa, T; Moch, M; Mönig, K; Monge, R; Montenegro, J; Moraes, D; Moreno, S; Morettini, P; Müller, U; Münich, K; Mulders, M; Mundim, L M; Murray, W; Muryn, B; Myatt, Gerald; Myklebust, T; Nassiakou, M; Navarria, Francesco Luigi; Nawrocki, K; Nicolaidou, R; Nikolenko, M; Oblakowska-Mucha, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Österberg, K; Ouraou, A; Oyanguren, A; Paganoni, M; Paiano, S; Palacios, J P; Palka, H; Papadopoulou, T D; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Peralta, L; Perepelitsa, V F; Perrotta, A; Petrolini, A; Piedra, J; Pieri, L; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Poireau, V; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Pukhaeva, N; Pullia, Antonio; Rames, J; Ramler, L; Read, A; Rebecchi, P; Rehn, J; Reid, D; Reinhardt, R; Renton, P B; Richard, F; Rídky, J; Rivero, M; Rodríguez, D; Romero, A; Ronchese, P; Rosenberg, E I; Roudeau, Patrick; Rovelli, T; Ruhlmann-Kleider, V; Ryabtchikov, D; Sadovskii, A; Salmi, L; Salt, J; Savoy-Navarro, A; Schwickerath, U; Segar, A; Sekulin, R L; Siebel, M; Sissakian, A N; Smadja, G; Smirnova, O G; Sokolov, A; Sopczak, A; Sosnowski, R; Spassoff, Tz; Stanitzki, M; Stocchi, A; Strauss, J; Stugu, B; Szczekowski, M; Szeptycka, M; Szumlak, T; Tabarelli de Fatis, T; Taffard, A C; Tegenfeldt, F; Timmermans, J; Tkatchev, L G; Tobin, M; Todorovova, S; Tomé, B; Tonazzo, A; Tortosa, P; Travnicek, P; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Turluer, M L; Tyapkin, I A; Tyapkin, P; Tzamarias, S; Uvarov, V; Valenti, G; van Dam, P; Van Eldik, J; Van Lysebetten, A; Van Remortel, N; Van Vulpen, I B; Vegni, G; Veloso, F; Venus, W A; Verdier, P; Verzi, V; Vilanova, D; Vitale, L; Vrba, V; Wahlen, H; Washbrook, A J; Weiser, C; Wicke, D; Wickens, J H; Wilkinson, G; Winter, M; Witek, M; Yushchenko, O P; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zhuravlov, V; Zimin, N I; Zinchenko, A I; Zupan, M
2004-01-01
The form factor of Lambda_b^0 baryons is estimated using 3.46 10^6 hadronic Z decays collected by the DELPHI experiment between 1992 and 1995. Charmed Lambda_c^+ baryons fully reconstructed in the pK-pi+, pK0_S, and Lambda pi+pi+pi- modes, are associated to a lepton with opposite charge in order to select Lambda_b^0 -> Lambda_c^+ l^- anti-nu_l decays. From a combined likelihood and event rate fit to the distribution of the Isgur-Wise variable w, and using the Heavy Quark Effective Theory (HQET), the slope of the b-baryon form factor is measured to be: rho-hat^2 = 2.03 +/- 0.46 (stat) ^{+0.72}_{-1.00} (syst). The exclusive semileptonic branching fraction Br(Lambda_b^0 -> Lambda_c^+ l^- anti-nu_l) can be derived from rho-hat^2 and is found to be (5.0^{+1.1}_{-0.8} (stat) ^{+1.6}_{-1.2} (syst))%. Limits on other branching fractions are also obtained.
Towards a dispersive determination of the η and η' transition form factors
Kubis, Bastian
2018-01-01
We discuss status and prospects of a dispersive analysis of the η and η' transition form factors. Particular focus is put on the various pieces of experimental information that serve as input to such a calculation. These can help improve on the precision of an evaluation of the η and η' pole contributions to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.
Towards a dispersive determination of the η and η′ transition form factors
Kubis Bastian
2018-01-01
Full Text Available We discuss status and prospects of a dispersive analysis of the η and η′ transition form factors. Particular focus is put on the various pieces of experimental information that serve as input to such a calculation. These can help improve on the precision of an evaluation of the η and η′ pole contributions to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.
Proton electromagnetic form factors: present status and future perspectives at PANDA
Tomasi-Gustafsson E.
2015-01-01
Full Text Available Data and models on electromagnetic proton form factors are reviewed, highlighting the contribution foreseen by the PANDA collaboration. Electromagnetic hadron form factors contain essential information on the internal structure of hadrons. Precise and surprising data have been obtained at electron accelerators, applying the polarization method in electron-proton elastic scattering. At electron-positron colliders, using initial state radiation, BABAR measured proton time-like form factors in a wide time-like kinematical region and the BESIII collaboration will measure very precisely proton and neutron form factors in the threshold region. In the next future an antiproton beam with momentum up to 15 GeV/c will be available at FAIR (Darmstadt. Measurements of the reaction p̅ + p → e+ + e− by the PANDA collaboration will contribute to the individual determination of electric and magnetic form factors in the time-like region of momentum transfer squared, as well as to their first determination in the unphysical region (below the kinematical threshold, through the reaction p̅ + p → e+ + e− + π0. From the discussion on feasibility studies at PANDA, we focus on the consequences of such measurements in view of an unified description of form factors in the full kinematical region. We present models which have the necessary analytical requirements and apply to the data in the whole kinematical region.
Light meson form factors at high Q2 from lattice QCD
Koponen, Jonna; Zimermmane-Santos, André; Davies, Christine; Lepage, G. Peter; Lytle, Andrew
2018-03-01
Measurements and theoretical calculations of meson form factors are essential for our understanding of internal hadron structure and QCD, the dynamics that bind the quarks in hadrons. The pion electromagnetic form factor has been measured at small space-like momentum transfer |q2| theory is applicable. This leaves a gap in the intermediate Q2 where the form factors are not known. As a part of their 12 GeV upgrade Jefferson Lab will measure pion and kaon form factors in this intermediate region, up to Q2 of 6 GeV2. This is then an ideal opportunity for lattice QCD to make an accurate prediction ahead of the experimental results. Lattice QCD provides a from-first-principles approach to calculate form factors, and the challenge here is to control the statistical and systematic uncertainties as errors grow when going to higher Q2 values. Here we report on a calculation that tests the method using an ηs meson, a 'heavy pion' made of strange quarks, and also present preliminary results for kaon and pion form factors. We use the nf = 2 + 1 + 1 ensembles made by the MILC collaboration and Highly Improved Staggered Quarks, which allows us to obtain high statistics. The HISQ action is also designed to have small dicretisation errors. Using several light quark masses and lattice spacings allows us to control the chiral and continuum extrapolation and keep systematic errors in check. Warning, no authors found for 2018EPJWC.17506016.
Quantum chromodynamics and the dynamics of hadrons
Brodsky, S.J.
1979-03-01
The application of perturbative quantum chromodynamics to the dynamics of hadrons at short distance is reviewed, with particular emphasis on the role of the hadronic bound state. A number of new applications are discussed, including the modification to QCD scaling violations in structure functions due to hadronic binding; a discussion of coherence and binding corrections to the gluon and sea-quark distributions; QCD radiative corrections to dimensional counting rules for exclusive processes and hadronic form factors at large momentum transfer; generalized counting rules for inclusive processes; the special role of photon-induced reactions in QCD, especially applications to jet production in photon-photon collisions, and photon production at large transverse momentum. Also presented is a short review of the central problems in large P/sub T/ hadronic reactions and the distinguishing characteristics of gluon and quark jets. 163 references
Magnetic form factors of the trinucleons
Schiavilla, R; Pandharipande, V R; Riska, Dan-Olof
1989-11-01
The magnetic form factors of ^{3}H and ^{3}He are calculated with the Monte Carlo method from variational ground-state wave functions obtained for the Argonne and Urbana two- and three-nucleon interactions. The electromagnetic current operator contains one- and two-body terms that are constructed so as to satisfy the continuity equation with the two-nucleon potential in the Hamiltonian. The results obtained with the Argonne two-nucleon interaction are in overall agreement with the empirical values. It appears that the remaining theoretical uncertainty, in the calculation of these form factors from a given interaction model, is dominated by that in the electromagnetic form factors of the nucleon. It is found that the isovector magnetic form factors are rather sensitive to the details of the isospin-dependent tensor force, and they are much better reproduced with the Argonne than the Urbana potential. The isoscalar magnetic form factors appear to be sensitive to the spin-orbit interactions, and are better reproduced with the Urbana potential. The Argonne potential has a stronger τ1∙τ2 tensor force, while the Urbana one has a shorter-range spin-orbit interaction.
Asymptotics of Heavy-Meson Form Factors
Grozin, A.G.; Grozin, Andrey G.; Neubert, Matthias
1997-01-01
Using methods developed for hard exclusive QCD processes, we calculate the asymptotic behaviour of heavy-meson form factors at large recoil. It is determined by the leading- and subleading-twist meson wave functions. For $1\\ll |v\\cdot v'|\\ll m_Q/\\Lambda$, the form factors are dominated by the Isgur--Wise function, which is determined by the interference between the wave functions of leading and subleading twist. At $|v\\cdot v'|\\gg m_Q/\\Lambda$, they are dominated by two functions arising at order $1/m_Q$ in the heavy-quark expansion, which are determined by the leading-twist wave function alone. The sum of these contributions describes the form factors in the whole region $|v\\cdot v'|\\gg 1$. As a consequence, there is an exact zero in the form factor for the scattering of longitudinally polarized $B^*$ mesons at some value $v\\cdot v'\\sim m_b/\\Lambda$, and an approximate zero in the form factor of $B$ mesons in the timelike region ($v\\cdot v'\\sim -m_b/\\Lambda$). We obtain the evolution equations and sum rules ...
Color-kinematic duality for form factors
Boels, Rutger H.; Kniehl, Bernd A.; Tarasov, Oleg V.; Yang, Gang
2012-12-01
Recently a powerful duality between color and kinematics has been proposed for integrands of scattering amplitudes in quite general gauge theories. In this paper the duality proposal is extended to the more general class of gauge theory observables formed by form factors. After a discussion of the general setup the existence of the duality is verified in two and three loop examples in four dimensional maximally supersymmetric Yang-Mills theory which involve the stress energy tensor multiplet. In these cases the duality reproduces known results in a particularly transparent and uniform way. As a non-trivial application we obtain a very simple form of the integrand of the four-loop two-point (Sudakov) form factor which passes a large set of unitarity cut checks.
Color-kinematic duality for form factors
Boels, Rutger H.; Kniehl, Bernd A.; Tarasov, Oleg V.; Yang, Gang [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik
2012-12-15
Recently a powerful duality between color and kinematics has been proposed for integrands of scattering amplitudes in quite general gauge theories. In this paper the duality proposal is extended to the more general class of gauge theory observables formed by form factors. After a discussion of the general setup the existence of the duality is verified in two and three loop examples in four dimensional maximally supersymmetric Yang-Mills theory which involve the stress energy tensor multiplet. In these cases the duality reproduces known results in a particularly transparent and uniform way. As a non-trivial application we obtain a very simple form of the integrand of the four-loop two-point (Sudakov) form factor which passes a large set of unitarity cut checks.
Paramagnetic form factors from itinerant electron theory
Cooke, J.F.; Liu, S.H.; Liu, A.J.
1985-01-01
Elastic neutron scattering experiments performed over the past two decades have provided accurate information about the magnetic form factors of paramagnetic transition metals. These measurements have traditionally been analyzed in terms of an atomic-like theory. There are, however, some cases where this procedure does not work, and there remains the overall conceptual problem of using an atomistic theory for systems where the unpaired-spin electrons are itinerant. We have recently developed computer codes for efficiently evaluating the induced magnetic form factors of fcc and bcc itinerant electron paramagnets. Results for the orbital and spin contributions have been obtained for Cr, Nb, V, Mo, Pd, and Rh based on local density bands. By using calculated spin enhancement parameters, we find reasonable agreement between theory and neutron form factor data. In addition, these zero parameter calculations yield predictions for the bulk susceptibility on an absolute scale which are in reasonable agreement with experiment in all treated cases except palladium
Weak form factors of beauty baryons
Ivanov, M.A.; Lyubovitskij, V.E.
1992-01-01
Full analysis of semileptonic decays of beauty baryons with J p =1/2 2 and J p =3/2 2 into charmed ones within the Quark Confinement Model is reported. Weak form factors and decay rates are calculated. Also the heavy quark limit m Q →∞ (Isgur-Wise symmetry) is examined. The weak heavy-baryon form factors in the Isgur-Wise limit and 1/m Q -corrections to them are computered. The Ademollo-Gatto theorem is spin-flavour symmetry of heavy quarks is checked. 33 refs.; 1 fig.; 9 tabs
Nucleon electromagnetic form factors with Wilson fermions
Goeckeler, M.; Haegler, P.; Horsley, R.
2007-10-01
The nucleon electromagnetic form factors continue to be of major interest for experimentalists and phenomenologists alike. They provide important insights into the structure of nuclear matter. For a range of interesting momenta they can be calculated on the lattice. The limiting factor continues to be the value of the pion mass. We present the latest results of the QCDSF collaboration using gauge configurations with two dynamical, non-perturbatively improved Wilson fermions at pion masses as low as 350 MeV. (orig.)
Nucleon electromagnetic form factors with Wilson fermions
Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Haegler, P. [Technische Univ. Muenchen, Garching (Germany). Inst. fuer Theoretische Physik; Horsley, R. [Edinburgh Univ. (GB). School of Physics] (and others)
2007-10-15
The nucleon electromagnetic form factors continue to be of major interest for experimentalists and phenomenologists alike. They provide important insights into the structure of nuclear matter. For a range of interesting momenta they can be calculated on the lattice. The limiting factor continues to be the value of the pion mass. We present the latest results of the QCDSF collaboration using gauge configurations with two dynamical, non-perturbatively improved Wilson fermions at pion masses as low as 350 MeV. (orig.)
Light Cone Sum Rules for gamma*N ->Delta Transition Form Factors
V.M. Braun; A. Lenz; G. Peters; A. Radyushkin
2006-02-01
A theoretical framework is suggested for the calculation of {gamma}* N {yields} {Delta} transition form factors using the light-cone sum rule approach. Leading-order sum rules are derived and compared with the existing experimental data. We find that the transition form factors in a several GeV region are dominated by the ''soft'' contributions that can be thought of as overlap integrals of the valence components of the hadron wave functions. The ''minus'' components of the quark fields contribute significantly to the result, which can be reinterpreted as large contributions of the quark orbital angular momentum.
Non-perturbative QCD and hadron physics
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)
Chiral analysis of baryon form factors
Gail, T.A.
2007-11-08
This work presents an extensive theoretical investigation of the structure of the nucleon within the standard model of elementary particle physics. In particular, the long range contributions to a number of various form factors parametrizing the interactions of the nucleon with an electromagnetic probe are calculated. The theoretical framework for those calculations is chiral perturbation theory, the exact low energy limit of Quantum Chromo Dynamics, which describes such long range contributions in terms of a pion-cloud. In this theory, a nonrelativistic leading one loop order calculation of the form factors parametrizing the vector transition of a nucleon to its lowest lying resonance, the {delta}, a covariant calculation of the isovector and isoscalar vector form factors of the nucleon at next to leading one loop order and a covariant calculation of the isoscalar and isovector generalized vector form factors of the nucleon at leading one loop order are performed. In order to perform consistent loop calculations in the covariant formulation of chiral perturbation theory an appropriate renormalization scheme is defined in this work. All theoretical predictions are compared to phenomenology and results from lattice QCD simulations. These comparisons allow for a determination of the low energy constants of the theory. Furthermore, the possibility of chiral extrapolation, i.e. the extrapolation of lattice data from simulations at large pion masses down to the small physical pion mass is studied in detail. Statistical as well as systematic uncertainties are estimated for all results throughout this work. (orig.)
Simple parametrization of nucleon form factors
Kelly, J.J.
2004-01-01
This Brief Report provides simple parametrizations of the nucleon electromagnetic form factors using functions of Q 2 that are consistent with dimensional scaling at high Q 2 . Good fits require only four parameters each for G Ep , G Mp , and G Mn and only two for G En
From form factors to generalized parton distributions
Diehl, Markus
2013-06-15
I present an extraction of generalized parton distributions from selected data on the electromagnetic nucleon form factors. The extracted distributions can in particular be used to quantify the contribution to the proton spin from the total angular momentum carried by valence quarks, as well as their transverse spatial distribution inside the proton.
Form factor expansion for thermal correlators
Pozsgay, B.; Takács, G.
2010-01-01
We consider finite temperature correlation functions in massive integrable quantum field theory. Using a regularization by putting the system in finite volume, we develop a novel approach (based on multi-dimensional residues) to the form factor expansion for thermal correlators. The first few terms
Electron form factors of deformable nuclei
Tartakovskii, V.K.; Isupov, V.Yu.
1988-01-01
Using the smallness of the deformation parameter of the nucleus, we obtain simple explicit expressions for the form factors of electroexcitation of the low-lying rotation-vibration states of light, deformable, even-even nuclei. The expressions satisfactorily describe the experimental data on the excitation of collective nuclear states by the inelastic scattering of fast electrons
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
Bagdasaryan, A.S.; Esaybegyan, S.V.; Ter-Isaakyan, N.L.
1982-01-01
In a model of hadrons composed of relativistic quarks a description of meson static characteristics and pion electromagnetic form factor in the range of small and intermediate values of momentum transfer 0 2 2 have obtained. It is shown that in such a model the data available on the pion electromagnetic form factor may be described basing on a simplest quark without gluon exchange. The contribution of a one-gluon exchange diagram in such a model cannot exceed 30%
K factor for Higgs boson production via gluon fusion process at hadron colliders
Tanaka, H.
1992-01-01
In this paper soft gluon corrections for Higgs boson production at hadron colliders are calculated. It is found that the soft contributions for the Higgs boson production via gluon fusion process is large and it cannot be neglected even at SSC energy. Some qualitative discussions for the QCD corrections to the Higgs boson production at hadron colliders and their background processes are presented for various Higgs boson mass cases
Composite hadrons and relativistic nuclei
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
ηc Hadroproduction at Large Hadron Collider Challenges NRQCD Factorization
Butenschoen Mathias
2017-01-01
Full Text Available We report on our analysis [1] of prompt ηc meson production, measured by the LHCb Collaboration at the Large Hadron Collider, within the framework of non-relativistic QCD (NRQCD factorization up to the sub-leading order in both the QCD coupling constant αs and the relative velocity v of the bound heavy quarks. We thereby convert various sets of J/ψ and χc,J long-distance matrix elements (LDMEs, determined by different groups in J/ψ and χc,J yield and polarization fits, to ηc and hc production LDMEs making use of the NRQCD heavy quark spin symmetry. The resulting predictions for ηc hadroproduction in all cases greatly overshoot the LHCb data, while the color-singlet model contributions alone would indeed be sufficient. We investigate the consequences for the universality of the LDMEs, and show how the observed tensions remain in follow-up works by other groups.
Asymptotics of QCD factorization in exclusive hadronic decays of B mesons
Becher, Thomas; Neubert, Matthias; Pecjak, Ben D.
2001-01-01
Using the renormalon calculus, we study the asymptotic behavior of the perturbative expansion of the hard-scattering kernels entering the QCD factorization formula for the nonleptonic weak decays B-bar 0 →D (*)+ M - , where M is a light meson. In the 'large-β 0 limit', the kernels are infrared finite and free of endpoint singularities to all orders of perturbation theory. The leading infrared renormalon singularity corresponding to a power correction of order Λ QCD /m b vanishes if the light meson has a symmetric light-cone distribution amplitude. We calculate the Borel transforms and the corresponding momentum distribution functions of the hard-scattering kernels, and resum the series of O(β 0 n-1 α s n ) corrections to explore the numerical significance of higher-order perturbative and power corrections. We also derive explicit expressions for the O(β 0 α s 2 ) contributions to the kernels, and for the renormalon singularities corresponding to power corrections of order (Λ QCD /m b ) 2 . Finally, we study the limit m c →0 relevant to charmless hadronic decays such as B→ππ
Perturbative QCD and electromagnetic form factors
Carlson, C.E.; Gross, F.
1987-01-01
We calculate nucleon magnetic form factors using perturbative QCD for several distribution amplitudes including a general one given in terms of Appell polynomials. We find that the magnitude and sign of both nucleon magnetic form factors can be explained within perturbative QCD. The observed normalization of G/sub Mp/ requires that the distribution amplitude be broader than its superhigh momentum transfer limit, and the G/sub Mn//G/sub Mp/ data may require the distribution amplitude to be asymmetric, in accord with distribution amplitudes derived from QCD sum rules. Some speculation as to how an asymmetric distribution amplitude can come about is offered. Finally, we show that the soft contributions corresponding to the particular distribution amplitudes we use need not be bigger than the data. 16 refs., 6 figs
Nucleon electromagnetic form factors from lattice QCD
Alexandrou, C.; Koutsou, G.; Negele, J. W.; Tsapalis, A.
2006-01-01
We evaluate the isovector nucleon electromagnetic form factors in quenched and unquenched QCD on the lattice using Wilson fermions. In the quenched theory we use a lattice of spatial size 3 fm at β=6.0 enabling us to reach low momentum transfers and a lowest pion mass of about 400 MeV. In the unquenched theory we use two degenerate flavors of dynamical Wilson fermions on a lattice of spatial size 1.9 fm at β=5.6 and lowest pion mass of about 380 MeV enabling comparison with the results obtained in the quenched theory. that unquenching effects are small for the pion masses considered in this work. We compare our lattice results to the isovector part of the experimentally measured form factors
Nucleon form factors. Probing the chiral limit
Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Haegler, P. [Technische Univ. Muenchen, Garching (Germany). Physik-Dept.; Horsley, R. [Edinburgh Univ. (GB). School of Physics] (and others)
2006-10-15
The electromagnetic form factors provide important hints for the internal structure of the nucleon and continue to be of major interest for experimentalists. For an intermediate range of momentum transfers the form factors can be calculated on the lattice. However, reliability of the results is limited by systematic errors due to the required extrapolation to physical quark masses. Chiral effective field theories predict a rather strong quark mass dependence in a range which was yet unaccessible for lattice simulations. We give an update on recent results from the QCDSF collaboration using gauge configurations with Nf=2, non-perturbatively O(a)-improved Wilson fermions at very small quark masses down to 340 MeV pion mass, where we start to probe the relevant quark mass region. (orig.)
Form factors of heavy mesons in QCD
Shifman, M.A.; Vysotsky, M.I.
1980-01-01
Logarithmic corrections to form factors of mesons built from heavy quarks are dirived in the framework of quantum chromodynamics. The reactions e + e - → etasub(c)γ and H → J/PSIγ are considered as an example. A novel feature as compared to the well studied problem of the pion form factor is the existence of the transformations between the quark-antiquark state c anti c and the gluonic one. O(αsub(s)) corrections are calculated exactly. An infinite series of the leading logarithmic terms is summed up with the help of the operator technique. Apart from already known results for quark operators some new results referring to gluon operators and their mixing with the quark ones are used. Two alternative derivations of the multiplicatively renormalizable operators are given. The first one reduces to a direct computation of the mixing matrix and its diagonalization, the second derivation is based on conformal symmetry considerations
Nucleon form factors. Probing the chiral limit
Goeckeler, M.; Haegler, P.; Horsley, R.
2006-10-01
The electromagnetic form factors provide important hints for the internal structure of the nucleon and continue to be of major interest for experimentalists. For an intermediate range of momentum transfers the form factors can be calculated on the lattice. However, reliability of the results is limited by systematic errors due to the required extrapolation to physical quark masses. Chiral effective field theories predict a rather strong quark mass dependence in a range which was yet unaccessible for lattice simulations. We give an update on recent results from the QCDSF collaboration using gauge configurations with Nf=2, non-perturbatively O(a)-improved Wilson fermions at very small quark masses down to 340 MeV pion mass, where we start to probe the relevant quark mass region. (orig.)
Elastic form factors at higher CEBAF energies
Petratos, G.G. [Kent State Univ., OH (United States)
1994-04-01
The prospects for elastic scattering from few body systems with higher beam energies at CEBAF is presented. The deuteron and{sup 3}He elastic structure functions A(Q{sup 2}) can be measured at sufficiently high momentum transfers to study the transition between the conventional meson-nucleon and the constituent quark-gluon descriptions. Possible improvements in the proton magnetic form factor data are also presented.
Baryon form factors in chiral perturbation theory
Kubis, B.; Meissner, U.G. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik
2001-01-01
We analyze the electromagnetic form factors of the ground state baryon octet to fourth order in relativistic baryon chiral perturbation theory. Predictions for the {sigma}{sup -} charge radius and the {lambda}-{sigma}{sup 0} transition moment are found to be in excellent agreement with the available experimental information. Furthermore, the convergence behavior of the hyperon charge radii is shown to be more than satisfactory. (orig.)
Electromagnetic form factors of composite systems
Nowak, E.J.
1978-01-01
Electromagnetic form factors are examined for a spin-zero, two-body composite system with emphasis on the case of small momentum transfer and/or deep (relativistic) binding. Perturbation theory calculations are first performed using spin-zero and then spin-one-half constituents. A dispersion representation of the bound-state vertex function is conjectured first for scalar and then for fermion constituents. Then a relativistic effective range approximation (RERA) is developed for each case and applied to the calculation of the electromagnetic form factor. The approach is applied to the study of the charge radii of the K 0 and K + mesons. The K/sub l3/ form factor is calculated in the fermion constituent RERA model, and restrictions are imposed on the model parameters from available experimental data. With these restrictions the limits 0.24fm less than or equal to √[abs. value ( 2 >/sub K 0 /)] less than or equal to = 0.36fm and 0.66fm less than or equal to = √( 2 >/sub K + /) less than or equal to 0.79fm are obtained for the kaon charge radii, and -.22 less than or equal to xi less than or equal to -.13 is found for the ratio of the neutral to charged kaon charge radius squared
Electric Form Factor of the Neutron
Feuerbach, Robert
2007-10-01
Recent polarization-based precision measurements of the nucleons' elastic electric form factors have led to surprising results. The measurement of the ratio of the proton's electromagnetic form factors, μpGE^p/GM^p, was found to drop nearly linearly with Q^2 out to at least 5 GeV^2, inconsistent with the older Rosenbluth-type experiments. A recent measurement of GE^n, the neutron's electric form-factor saw GE^n does not fall off as quickly as commonly expected up to Q^2 1.5 GeV^2. Extending this study, a precision measurement of GE^n up to Q^2=3.5 GeV^2 was completed in Hall A at Jefferson Lab. The ratio GE^n/GM^n was measured through the beam-target asymmetry A of electrons quasi-elastically scattered off polarized neutrons in the reaction ^3He(e,e' n). The experiment took full advantage of the electron beam, recent target developments, as well as two detectors new to Jefferson Lab. The measurement used the accelerator's 100% duty-cycle high-polarization (typically 84%) electron beam and a new, hybrid optically-pumped polarized ^3He target which achieved in-beam polarizations in excess of 50%. A medium acceptance (80msr) open-geometry magnetic spectrometer (BigBite) detected the scattered electron, while a geometrically matched neutron detector observed the struck neutron. Preliminary results from this measurement will be discussed and compared to modern calculations of GE^n.
Form factors and excitations of topological solitons
Weir, David J.; Rajantie, Arttu
2011-01-01
We show how the interaction properties of topological solitons in quantum field theory can be calculated with lattice Monte Carlo simulations. Topologically nontrivial field configurations are key to understanding the nature of the QCD vacuum through, for example, the dual superconductor picture. Techniques that we have developed to understand the excitations and form factors of topological solitons, such as kinks and 't Hooft-Polyakov monopoles, should be equally applicable to chromoelectric flux tubes. We review our results for simple topological solitons and their agreement with exact results, then discuss our progress towards studying objects of interest to high energy physics.
Recent Studies of Nucleon Electromagnetic Form Factors
Gilad, Shalev
2010-01-01
The electromagnetic form factors of nucleons are fundamental quantities in nucleon structure. As such, they have been studied extensively both theoretically and experimentally. Significant progress has been made with new measurements at Jlab, MAMI and MIT-Bates, with emphases on expanding the momentum-transfer range and on higher precision. In this paper, we describe the status of this field and present new results from measurements at both low and high momentum transfers. We also compare the experimental data to model predictions, and mention possible implications of the new results to other fields.
Medium modifications of nucleon electromagnetic form factors
Horikawa, T. [Department of Physics, School of Science, Tokai University, Hiratsuka-shi, Kanagawa 259-1292 (Japan); Bentz, W. [Department of Physics, School of Science, Tokai University, Hiratsuka-shi, Kanagawa 259-1292 (Japan)]. E-mail: bentz@keyaki.cc.u-tokai.ac.jp
2005-11-28
We use the Nambu-Jona-Lasinio model as an effective quark theory to investigate the medium modifications of the nucleon electromagnetic form factors. By using the equation of state of nuclear matter derived in this model, we discuss the results based on the naive quark-scalar diquark picture, the effects of finite diquark size, and the meson cloud around the constituent quarks. We apply this description to the longitudinal response function for quasielastic electron scattering. RPA correlations, based on the nucleon-nucleon interaction derived in the same model, are also taken into account in the calculation of the response function.
Neutron electric form factor via recoil polarimetry
Richard Madey; Andrei Semenov; Simon Taylor; Aram Aghalaryan; Erick Crouse; Glen MacLachlan; Bradley Plaster; Shigeyuki Tajima; William Tireman; Chenyu Yan; Abdellah Ahmidouch; Brian Anderson; Razmik Asaturyan; O. Baker; Alan Baldwin; Herbert Breuer; Roger Carlini; Michael Christy; Steve Churchwell; Leon Cole; Samuel Danagoulian; Donal Day; Mostafa Elaasar; Rolf Ent; Manouchehr Farkhondeh; Howard Fenker; John Finn; Liping Gan; Kenneth Garrow; Paul Gueye; Calvin Howell; Bitao Hu; Mark Jones; James Kelly; Cynthia Keppel; Mahbubul Khandaker; Wooyoung Kim; Stanley Kowalski; Allison Lung; David Mack; D. Manley; Pete Markowitz; Joseph Mitchell; Hamlet Mkrtchyan; Allena Opper; Charles Perdrisat; Vina Punjabi; Brian Raue; Tilmann Reichelt; Joerg Reinhold; Julie Roche; Yoshinori Sato; Wonick Seo; Neven Simicevic; Gregory Smith; Samuel Stepanyan; Vardan Tadevosyan; Liguang Tang; Paul Ulmer; William Vulcan; John Watson; Steven Wells; Frank Wesselmann; Stephen Wood; Chen Yan; Seunghoon Yang; Lulin Yuan; Wei-Ming Zhang; Hong Guo Zhu; Xiaofeng Zhu
2003-01-01
The ratio of the electric to the magnetic form factor of the neutron, G En /G Mn , was measured via recoil polarimetry from the quasielastic d((pol-e),e(prime)(pol-n)p) reaction at three values of Q 2 [viz., 0.45, 1.15 and 1.47 (GeV/c) 2 ] in Hall C of the Thomas Jefferson National Accelerator Facility. Preliminary data indicate that G En follows the Galster parameterization up to Q 2 = 1.15 (GeV/c) 2 and appears to rise above the Galster parameterization at Q 2 = 1.47 (GeV/c) 2
Axial nucleon form factors from lattice QCD
Alexandrou, C.; Brinet, M.; Carbonell, J.; Harraud, P. A.; Papinutto, M.; Constantinou, M.; Guichon, P.; Jansen, K.; Korzec, T.
2011-01-01
We present results on the nucleon axial form factors within lattice QCD using two flavors of degenerate twisted mass fermions. Volume effects are examined using simulations at two volumes of spatial length L=2.1 fm and L=2.8 fm. Cut-off effects are investigated using three different values of the lattice spacings, namely a=0.089 fm, a=0.070 fm and a=0.056 fm. The nucleon axial charge is obtained in the continuum limit and chirally extrapolated to the physical pion mass enabling comparison with experiment.
Form factors of heavy mesons in QCD
Shifman, M A; Vysotsky, M I [Moskovskii Inst. Theoreticheskoj i Ehksperimental' noj Fiziki (USSR)
1981-08-10
We discuss logarithmic corrections to form factors of mesons built from heavy quarks. The reactions e/sup +/e/sup -/ ..-->.. etasub(c)..gamma.. and H ..-->.. J/psi..gamma.. are considered as an example. A novel feature as compared to the well-studied problem of the pion form factor is the existence of transitions between the quark-antiquark state canti c and the gluonic one. O(..cap alpha..sub(s)) corrections are calculated exactly. An infinite series of the leading logarithmic terms (..cap alpha..sub(s)ln(Q/sup 2//m/sup 2/sub(c)))sup(n) is summed up with the help of the operator technique. Apart from results already known for quark operators, we use some new results referring to gluon operator and their mixing with those made from quarks. Two alternative derivations of the multiplicatively renormalizable operators are given. The first one reduces to a direct computation of the mixing matrix and its diagonalization, the second is based on conformal symmetry considerations.
Nucleon Form Factors Using Spin Degrees of Freedom
Jones, Mark
2002-01-01
An overview of recent measurements of the neutron and proton electromagnetic form factors from double polarization experiments. Spin observables are sensitive to the product of nucleon form factor which allows access to the small nucleon electric form factors
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
Measurement of the form factor ratios in semileptonic decays of charm mesons
R. Zaliznyak
1999-01-01
I have measured the form factor ratios r 2 = A 2 (0)/A 1 (0) and r V = V (0)/A 1 (0) in the semileptonic charm meson decay D + → (anti K) *0 e + ν e from data collected by the Fermilab E791 collaboration. Form factors are introduced in the calculation of the hadronic current in semileptonic decays of strange, charm, or bottom mesons, such as D + → (anti K) *0 e + ν e . Semileptonic decays provide insight into quark coupling to the W boson since the leptonic and hadronic amplitudes in the Feynman diagram for the decay are completely separate. There are no strong interactions between the final state leptons and quarks. A number of theoretical models predict the values of the form factors for D + → (anti K) *0 e + ν e , though there is a large range of predictions. E791 is a hadroproduction experiment that recorded over 20 billion interactions with a 500 GeV π - beam incident on five thin targets during the 1991-92 Fermilab fixed-target run. Approximately 3000 D + → (anti K) *0 e + ν e decays are fully reconstructed. In order to extract the form factor ratios from the data, I implement a multidimensional unbinned maximum likelihood fit with a large sample of simulated (Monte Carlo) D + → (anti K) *0 e + ν e events. The large E791 data sample provides the most precise measurement of the form factor ratios to date. The measured values for the form factor ratios are r 2 = 0.71 ± 0.08 ± 0.09 and r V = 1.84 ± 0.11 ± 0.08. These results are in good agreement with some Lattice Gauge calculations. However the agreement with quark model predictions is not as good
Contribution of meson exchange currents to magnetic form factor of a few complex nuclei
Mathiot, J.F.
1981-12-01
We were interested in the contribution of meson exchange currents (MEC) to the magnetic form factor (MFF) of 49 Ti, 51 V, 87 Sr, 93 Nb at high momentum transfer (1.8 fm -1 to 3.2 fm -1 ). We found that the contribution of tensor correlations to the 1 S 0 - 3 S 1 transition of MEC (adding the 3 D 1 tensor part to the 3 S 1 relative state) multiply the previous calculations by a factor of 2.5 to 4. The sensitivity of MEC to the hadronic form factor is also estimated. It remains of discrepancy of a factor 2 for the MFF at 3 fm -1 for the first three nuclei [fr
Model analysis of the world data on the pion transition form factor
Noguera, S.; Vento, V.
2012-01-01
We discuss the impact of recent Belle data on our description of the pion transition form factor based on the assumption that a perturbative formalism and a nonperturbative one can be matched in a physically acceptable manner at a certain hadronic scale Q 0 . We discuss the implications of the different parameters of the model in comparing with world data and conclude that within experimental errors our description remains valid. Thus we can assert that the low Q 2 nonperturbative description together with an additional 1/Q 2 term at the matching scale have a strong influence on the Q 2 behavior up to very high values of Q 2 . (orig.)
Pion transition form factor in k{sub T} factorization
Li, Hsiang-nan [Academica Sinica, Taipei, Taiwan (China). Inst. of Physics; Tsing-Hua Univ., Hsinchu, Taiwan (China). Dept. of Phyiscs; National Cheng-Kung Univ., Tainan, Taiwan (China). Dept. of Physics; National Cheng-Chi Univ, Taipei, Taiwan (China). Inst. of Applied Physics; Mishima, Satoshi [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2009-07-15
It has been pointed out that the recent BaBar data on the {pi}{gamma}{sup *} {yields} {gamma} transition form factor F{sub {pi}}{sub {gamma}}(Q{sup 2}) at low (high) momentum transfer squared Q{sup 2} indicate an asymptotic (flat) pion distribution amplitude. These seemingly contradictory observations can be reconciled in the k{sub T} factorization theorem: the increase of the measured Q{sup 2}FF{sub {pi}}{sub {gamma}}(Q{sup 2}) for Q{sup 2} > 10 GeV{sup 2} is explained by convoluting a k{sub T} dependent hard kernel with a flat pion distribution amplitude, k{sub T} being a parton transverse momentum. The low Q{sup 2} data are accommodated by including the resummation of {alpha}{sub s} ln{sup 2}x, x being a parton momentum fraction, which provides a stronger suppression at the endpoints of x. The next-to-leading-order correction to the pion transition form factor is found to be less than 20% in the considered range of Q{sup 2}. (orig.)
Behavior of the hadron potential at large distances and properties of the hadron spin-flip amplitude
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.)
Hadronic wave functions and high momentum transfer interactions in quantum chromodynamics
Brodsky, S.J.; Huang, T.; Lepage, G.P.
1983-01-01
This chapter emphasizes the utility of a Fock state representation of the meson and baryon wave functions as a means not only to parametrize the effects of bound state dynamics in QCD phenomena, but also to interrelate exclusive, inclusive, and higher twist processes. Discusses hadronic wave functions in QCD, measures of hadronic wave functions (form factors of composite systems, form factors of mesons, the meson distribution amplitude); large momentum transfer exclusive processes (two-photon processes); deep inelastic lepton scattering; and the phenomenology of hadronic wave functions (measures of hadron wave functions, constraints on the pion and proton valence wave function, quark jet diffraction excitation, the ''unveiling'' of the hadronic wave function and intrinsic charm). Finds that the testing ground of perturbative QCD where rigorous, definitive tests of the theory can be made can now be extended throughout a large domain of large momentum transfer exclusive and inclusive lepton, photon, and hadron reactions
Parallel Integer Factorization Using Quadratic Forms
McMath, Stephen S
2005-01-01
Factorization is important for both practical and theoretical reasons. In secure digital communication, security of the commonly used RSA public key cryptosystem depends on the difficulty of factoring large integers...
Analytical and unitary approach in mesons electromagnetic form factor applications
Liptaj, A.
2010-07-01
In the dissertation thesis we address several topics related to the domain of particle physics. All of them represent interesting open problems that can be connected to the elastic or transition electromagnetic form factors of mesons, the form factors being the main objects of our interest. Our ambition is to contribute to the solution of these problems and use for that purpose known analytic properties of the form factors and the unitarity condition. These two tools are very powerful in the low energy domain (such as bound states of partons), where the perturbative QCD looses its validity. This is the motivation for construction of the unitary and analytic (U and A) models of studied form factors, that enable us to get the majority of our results. We use the U and A model to evaluate the contribution of the processes e"+e"- → Pγ, P = π"0, η, η to the muon magnetic anomaly a_μ in the lowest order of the hadronic vacuum polarization. For the contribution a_μ"h"a"d","L"O (π"+π"-) we demonstrate, that the use of the model leads to a dramatic error reduction with respect to the results of other authors. We also get a shift in the central value in the 'correct' direction, that brings the theoretical value closer to the experimental one. This results encourages us to use the model also for the evaluation of a_μ"h"a"d","L"O (P_γ). These contributions are smaller, however the precision of the experiment makes their evaluation necessary. We further use the U and A model of the transition form factors of π"0, η and η"' mesons to predict the partial decay widths of these particles Γ_π_"0_→_γ_γ and Γ_η_→_γ_γ and Γ_η_"'_→_γ_γ. In this way we make an independent cross check of the PDG table values. We find an agreement in the case of Γ_η_→_γ_γ and Γ_η_"'_→_γ_γ, even a smaller uncertainty for Γ_η_"'_→_γ_γ. In the case of Γ_π_"0_→_γ_γ we find a disagreement that points to an interesting problem. We wonder whether it could be
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
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)
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.
Feasibility studies of time-like proton electromagnetic form factors at PANDA-FAIR
Dbeyssi, Alaa; Capozza, Luigi; Deiseroth, Malte; Froehlich, Bertold; Khaneft, Dmitry; Mora Espi, Maria Carmen; Noll, Oliver; Rodriguez Pineiro, David; Valente, Roserio; Zambrana, Manuel; Zimmermann, Iris [Helmholtz-Institut Mainz, Mainz (Germany); Maas, Frank [Helmholtz-Institut Mainz, Mainz (Germany); Institute of Nuclear Physics, Mainz (Germany); PRISMA Cluster of Excellence, Mainz (Germany); Marchand, Dominique; Tomasi-Gustafsson, Egle; Wang, Ying [Institut de Physique Nucleaire, Orsay (France); Collaboration: PANDA-Collaboration
2015-07-01
Electromagnetic form factors are fundamental quantities which describe the intrinsic electric and magnetic distributions of hadrons. Time-like proton form factors are experimentally accessible through the annihilation processes anti p+p <-> e{sup +}+e{sup -}. Their measurement in the time-like region had been limited by the low statistics achieved by the experiments. This contribution reports on the results of Monte Carlo simulations for future measurements of electromagnetic proton form factors at PANDA (antiProton ANnihilation at DArmstadt). In frame of the PANDARoot software, the statistical precision at which the proton form factors will be determined is estimated. The signal (anti p+p → e{sup +}+e{sup -}) identification and the suppression of the main background process (anti p+p → π{sup +}+π{sup -}) are studied. Different methods have been used and/or developed to generate and analyse the processes of interest. The results show that time-like proton form factors will be measured at PANDA with unprecedented statistical accuracy.
Effects of an electromagnetic quark form factor on meson properties
Silvestre-Brac, B.
2002-01-01
A form factor is introduced in the quark electromagnetic current. Its effect is analyzed on charge mean square radii and form factors in the mesonic sector. The decay of a vector meson into lepton-antilepton pair is also affected. Two different expressions for the form factors, and two different types of quark potential are tested and some relativistic kinematical corrections are proposed. In any case the introduction of a quark form factor greatly improves the agreement with experimental data
B-decay form factors from QCD sum rules
Offen, Nils
2008-01-01
In the Standard Model of particle physics there is only one source of CP-violation. Namely, a single complex phase in the unitary 3 x 3 CKM-Matrix governing flavor transitions in the weak interaction. The unitarity is usually visualized by a triangle in the complex ρ - η-plane. Therefore testing this framework comes down to measuring weak decays, relating observables to sides and angles of this so called Unitarity Triangle(UT). Particular interest in this respect is payed to decays of mesons containing a heavy b-quark, giving the opportunity to alone determine all parameters of the UT. Doing this is far from easy. Besides tedious experimental measurements the theoretical calculations are plagued by hadronic quantities which cannot be determined by perturbation theory. In this work several of these quantities so called form factors are computed using the well known method of light cone sum rules(LCSR). Two different setups have been used. One, established in this work, utilizing a correlation function with an on-shell B-Meson and one following the traditional calculation by taking the light meson on-shell. Both using light cone expansion in the respective on-shell mesons distribution amplitudes. While the first approach allows to calculate a whole bunch of phenomenologically interesting quantities by just changing Dirac-structures of the relevant currents it has the drawback that it does not have access to the well developed twist expansion of the latter. To incorporate higher Fock-state contributions the first models for three-particle distribution amplitudes of the B-Meson have been derived. α s -corrections remain out of the scope of this work. Nevertheless does a comparison with more sophisticated methods show an encouraging numerical agreement. In the second setup all known corrections especially the never verified α s -corrections to Twist three terms have been recalculated and a competitive result for the CKM-matrixelement vertical stroke V ub vertical
Form factors in (HI,HI') direct reactions
Chu, Y.H.
1981-01-01
Using the semiclassical theory, the inelastic transition form factors are analyzed. For the first order form factors, we find that: (i) In the strong absorption limit, the Austern-Blair theory is a good approximation to the inelastic form factor--even in highly mismatched reactions. (ii) In weak to moderate absorption, the amplitude of the inelastic form factor oscillates due to overlapping potential resonances. The internal part of the form factor can be expressed in a simple form, which may easily be used to analyze heavy-ion inelastic scattering. (iii) In the presence of an isolated resonance, the inelastic form factor is enhanced greatly at the resonance due to multiple reflections inside the potential well. The second order form factors contain two terms, i.e. the one-step direct process (OSD) term and the two-step process (TS) term. It is found that: (i) In the strong absorption limit, OSD and TS form factors are equally important and interfere destructively near the grazing angular momentum. The Austern-Blair theory gives satisfactory results for well-matched reactions. The angular distributions of the mutual and double excitations are out of phase compared with that of the single excitation. (ii) For the weak absorption case, the internal part of the TS form factor is so enhanced that the OSD form factor can simply be neglected. The internal TS form factor can be parameterized in a form proportional to the internal-wave elastic Smatrix, where the angular distribution shows characteristically refractive phenomenon
MesonNet Workshop on Meson Transition Form Factors
Eidelman, S; Hanhart, C; Kubis, B; Kupsc, A; Leupold, S; Moskal, P; Schadmand, S
2012-01-01
The mini-proceedings of the Workshop on Meson Transition Form Factors held in Cracow from May 29th to 30th, 2012 introduce the meson transition form factor project with special emphasis on the interrelations between the various form factors (on-shell, single off-shell, double off-shell). Short summaries of the talks presented at the workshop follow.
Eyraud, L; Furget, C.; Goy, J.; Kox, S.; Merchez, F.; Pastor, A.; Real, J.S.; Russew, T.; Tieulent, R.; Voutier, E.
1997-01-01
Over these two years, our group has been worked in hadronic physics at Saturn and CEBAF using the polarimeter POLDER. Tensor polarization observables have been measured in the reaction H(p bar, d bar)π + between 580 and 1300 MeV proton energy. The group has also been leader in an experiment, performed in 1997 at CEBAF. By measuring the t 20 polarization of the recoil deuteron produced in the elastic electron-deuteron scattering at large Q 2 , the separation of the charge and quadrupole form-factors of the deuteron will be performed for Q=4.1-6.8 fm -1 . Finally, we were involved in the construction and test of the neutron polarimeter HARP and in the definition of the physics program of the ELFE project. (authors)
Electromagnetic form factors in the light-front dynamics
Karmanov, V.A.; Smirnov, A.V.
1992-01-01
It is shown that the electromagnetic vertex of a nucleus (and of any bound system), expressed through the wave function in the light-front dynamics at relativistic values of momentum transfer, contains a contribution of nonphysical form factors which increases the total number of invariant form factors (for the deuteron from 3 up to 11). This fact explains an ambiguity in the form factors calculated previously. The physical and nonphysical form factors are covariantly separated. Explicit expressions for physical form factors of systems with spin 0, 1/2 and 1 through the vertex functions are obtained. (orig.)
Magnetic form factors of rare earth ions
Deckman, H.W.
1976-01-01
The magnetic scattering of neutrons by atoms has been investigated by exploiting its similarity to the radiation problem in spectroscopy. Expressions for the magnetic scattering amplitude were developed for cases in whcih an atom in the l/sup n/ electronic configuration is described either by a relativistic or nonrelativistic Hamiltonian. For each of these cases, it has been shown that the magnetic scattering amplitude can be expressed in terms of relativistic or nonrelativistic matrix elements of magnetic and electric multipole operators. For a nonrelativistic atom, the calculation of these matrix elements has been separated into evaluating radial matrix elements and matrix elements of Racah tensors W/(sup 0,k)k/ and W/(sup 1,k')k/. For a relativistic atom the effective operator approach has been used to define effective multipole operators so that a relativistic result is obtained by taking matrix elements of these effective operators between nonrelativistic states of the atom. The calculation of matrix elements of these effective operators has been reduced to evaluating relativistic radial integrals and matrix elements of the Racah tensors taken between nonrelativistic states of the atom. It is shown tha for the case of elastic scattering by either a relativistic or nonrelativistic atom in single Russel-Saunders state, the magnetic scattering amplitude can be written in the conventional form p(vector q)vector q/sub m/.vector sigma. General expressions for p(vector q) as well as elastic magnetic form factorshave been obtained. The formalism has been illustrated throughout by applying it to the case of scattering by rare earth ions
Tensor form factor for the D → π(K) transitions with Twisted Mass fermions.
Lubicz, Vittorio; Riggio, Lorenzo; Salerno, Giorgio; Simula, Silvano; Tarantino, Cecilia
2018-03-01
We present a preliminary lattice calculation of the D → π and D → K tensor form factors fT (q2) as a function of the squared 4-momentum transfer q2. ETMC recently computed the vector and scalar form factors f+(q2) and f0(q2) describing D → π(K)lv semileptonic decays analyzing the vector current and the scalar density. The study of the weak tensor current, which is directly related to the tensor form factor, completes the set of hadronic matrix element regulating the transition between these two pseudoscalar mesons within and beyond the Standard Model where a non-zero tensor coupling is possible. Our analysis is based on the gauge configurations produced by the European Twisted Mass Collaboration with Nf = 2 + 1 + 1 flavors of dynamical quarks. We simulated at three different values of the lattice spacing and with pion masses as small as 210 MeV and with the valence heavy quark in the mass range from ≃ 0.7 mc to ≃ 1.2mc. The matrix element of the tensor current are determined for a plethora of kinematical conditions in which parent and child mesons are either moving or at rest. As for the vector and scalar form factors, Lorentz symmetry breaking due to hypercubic effects is clearly observed in the data. We will present preliminary results on the removal of such hypercubic lattice effects.
Hadronization of QCD and effective interactions
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
THE FACTORS FORMING QUALITY OF GRANULATED SUGAR
N. G. Kulneva
2015-01-01
Full Text Available Sugar, with good taste and high caloric, is one of the most popular human food. Consumers sugar must be sure that the sugar under normal conditions of use is of high quality and is not harmful to the health of the product. One reason for the decline in the quality of sugar is bacterial contamination. This is because the sugar industry products are good targets for the development of different groups of microorganisms, e.g., Bacillus subtilis, Clostridium perfringes, Leuconostoc dextranicum, Torula alba, Pseudomonas fluorescens, Sarcina lutea and others. These organisms are affected with beets, and then with sugar beet chips and diffusion juice fall into the processing line of sugar production. Their number in the diffusion juice varies and depends on many facto rs such as the quality of raw materials, the quality of cleaning beet root colonization of transporter-washing and the supply of water to the diffusion process, the temperature of the diffusion and others. In the diffusion unit has the most favorable conditions for the development of micro-organisms. Some of them, especially resistant bacteria and thermophilic bacteria or their spores, forming a capsule which protects against external influences occur in the final product sugar. When injected into the fresh crop of product (juice, syrup, they begin to multiply rapidly, causing difficulties in the process. The higher seeding beet microorganisms, the more they decompose and emit sucrose metabolism byproducts. To reduce the negative impact of microbiological and reduce losses from decomposition of sucrose conducted research on the possibility of using chlorine-containing substances in the sugar industry. It was established experimentally that the investigated chlorinated drug has bacteriostatic action and can be recommended for use in sugar beet production.
Measurement of the form factor ratios in semileptonic decays of charm mesons
Zaliznyak, Renata [Stanford Univ., CA (United States)
1998-05-01
I have measured the form factor ratios r_{2} = A_{2} (0)/A_{1} (0) and r_{V} = V (0)/A_{1} (0) in the semileptonic charm meson decay D^{+} → $\\bar{K}$^{*0} e^{+}v_{e} from data collected by the Fermilab E791 collaboration. Form factors are introduced in the calculation of the hadronic current in semileptonic decays of strange, charm, or bottom mesons, such as D^{+} → $\\bar{K}$^{*0} e^{+} v_{e} . Semileptonic decays provide insight into quark coupling to the W boson since the leptonic and hadronic amplitudes in the Feynman diagram for the decay are completely separate. There are no strong interactions between the final state leptons and quarks. A number of theoretical models predict the values of the form factors for D^{+} → $\\bar{K}$^{*0} e^{+} v_{e} , though there is a large range of predictions. E791 is a hadroproduction experiment that recorded over 20 billion interactions with a 500 GeV π^{-} beam incident on five thin targets during the 1991-92 Fermilab fixed-target run. Approximately 3000 D^{+} → $\\bar{K}$^{*0} e^{+} v_{e} decays are fully reconstructed. In order to extract the form factor ratios from the data, I implement a multidimensional unbinned maximum likelihood fit with a large sample of simulated (Monte Carlo) D^{+} → $\\bar{K}$^{*0} e^{+}v_{e} events. The large E791 data sample provides the most precise measurement of the form factor ratios to date. The measured values for the form factor ratios are r_{2} = 0.71 ± 0.08 ± 0.09 and r_{V} = 1.84 ± 0.11 ±} 0.08. These results are in good agreement with some Lattice Gauge calculations. However the agreement with quark model predictions is not as good.
Hadronic wave functions at short distances and the operator product expansion
Brodsky, S.J.; Lepage, G.P.
1980-01-01
The operator product expansion, of appropriate products of quark fields, is used to find the anamalous dimensions which control the short distance behavior of hadronic wave functions. This vehavior in turn controls the high-Q 2 limit of hadronic form factors. In particular, we relate each anamalous dimension of the nonsinglet structure functions to a corresponding logarithmic correction factor to the nominal αsub(s)(Q 2 )/Q 2 fall off of meson form factors. Unlike the case of deep inelastic lepton-hadron scattering, the operator product necessary here involves extra terms which do not contribute to forward matrix elements. (orig.)
The QCD form factor of massive quarks and applications
Moch, S.
2009-11-01
We review the electromagnetic form factor of heavy quarks with emphasis on the QCD radiative corrections at two-loop order in the perturbative expansion. We discuss important properties of the heavy-quark form factor such as its exponentiation in the high-energy limit and its role in QCD factorization theorems for massive n-parton amplitudes. (orig.)
Asymptotical behaviour of pion electromagnetic form factor in QCD
Efremov, A.V.; Radyushkin, A.V.
1978-01-01
In the framework of the renormalizable quantum field theory a new approach is developed to the investigation of asymptotical behaviour of two-particle bound state electromagnetic form factor. It is shown that the behaviour of the pion EM form factor in quantum chromodynamics at sufficiently large momentum transfers is controlled by the short-distance dynamics only. The formula is obtained which expresses the asymptotical behaviour of the pion form factor in terms of the fundamental constants of the theory
Analytical evaluation of atomic form factors: Application to Rayleigh scattering
Safari, L., E-mail: laleh.safari@ist.ac.at [IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg (Austria); Department of Physics, University of Oulu, Box 3000, FI-90014 Oulu (Finland); Santos, J. P. [Laboratório de Instrumentação, Engenharia Biomédica e Física da Radiação (LIBPhys-UNL), Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Amaro, P. [Laboratório de Instrumentação, Engenharia Biomédica e Física da Radiação (LIBPhys-UNL), Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Physikalisches Institut, Universität Heidelberg, D-69120 Heidelberg (Germany); Jänkälä, K. [Department of Physics, University of Oulu, Box 3000, FI-90014 Oulu (Finland); Fratini, F. [Department of Physics, University of Oulu, Box 3000, FI-90014 Oulu (Finland); Institute of Atomic and Subatomic Physics, TU Wien, Stadionallee 2, 1020 Wien (Austria); Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG (Brazil)
2015-05-15
Atomic form factors are widely used for the characterization of targets and specimens, from crystallography to biology. By using recent mathematical results, here we derive an analytical expression for the atomic form factor within the independent particle model constructed from nonrelativistic screened hydrogenic wave functions. The range of validity of this analytical expression is checked by comparing the analytically obtained form factors with the ones obtained within the Hartee-Fock method. As an example, we apply our analytical expression for the atomic form factor to evaluate the differential cross section for Rayleigh scattering off neutral atoms.
Identifying Multiquark Hadrons from Heavy Ion Collisions
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.
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)
Kaidalov, A.B.; Kondratyuk, L.A.; Tchekin, D.V.
2000-01-01
The electromagnetic form factors for pions and nucleons are considered within the model of quark-gluon strings, where the momentum-transfer dependence of hadronic form factors is determined by the intercepts of the corresponding Regge trajectories and by the Sudakov form factor. Analytic expressions found for form factors in the timelike region admit an analytic continuation to the spacelike region. The resulting form factors for pions and nucleons comply well with experimental data both for positive and for negative values of the squared momentum transfer q 2 . It is shown that the distinctions between the absolute values of the pion and nucleon form factors F π (q 2 ), G m (q 2 ), and F 2 (q 2 ) at positive values of q 2 and those at negative values of this variable are associated with the analytic properties of the double-logarithmic term in the exponent of the Sudakov form factor. The spin structure of the amplitudes for quark transitions into hadrons that is proposed in the present study makes it possible to describe fairly well available experimental data on the Pauli form factor F 2 and on the ratio G e /G m
High intensity hadron accelerators
Teng, L.C.
1989-05-01
This rapporteur report consists mainly of two parts. Part I is an abridged review of the status of all High Intensity Hadron Accelerator projects in the world in semi-tabulated form for quick reference and comparison. Part II is a brief discussion of the salient features of the different technologies involved. The discussion is based mainly on my personal experiences and opinions, tempered, I hope, by the discussions I participated in in the various parallel sessions of the workshop. In addition, appended at the end is my evaluation and expression of the merits of high intensity hadron accelerators as research facilities for nuclear and particle physics
Nucleon mass difference and off-shell form factors
Kimel, I.
1981-08-01
The use of off-shell form factors in calculating the proton-neutron mass difference is advocated. These form factors appear in a Cottingham rotated Born-like expression for the mass difference and could lead to a good value for Δ = M sub(p) - M sub(n). (Author) [pt
The heavy quark form factors at two loops
Ablinger, J.; Schneider, C. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation (RISC); Behring, A. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); RWTH Aachen Univ. (Germany). Inst. fuer Theoretische Teilchenphysik und Kosmologie; Bluemlein, J.; Freitas, A. de; Marquard, P.; Rana, N. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Falcioni, G. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Nikhef, Amsterdam (Netherlands). Theory Group
2017-12-15
We compute the two-loop QCD corrections to the heavy quark form factors in case of the vector, axial-vector, scalar and pseudo-scalar currents up to second order in the dimensional parameter ε=(4-D)/2. These terms are required in the renormalization of the higher order corrections to these form factors.
Model of separated form factors for unilamellar vesicles
Kiselev, M.A.; Aksenov, V.L.; Lesieur, P.; Lombardo, D.; Kiselev, A.M.
2001-01-01
A new model of separated form factors is proposed for the evaluation of small-angle neutron scattering curves from large unilamellar vesicles. The validity of the model was checked via comparison with the model of a hollow sphere. The model of separated form factors and the hollow sphere model give a reasonable agreement in the evaluation of vesicle parameters
Molecular form factors in X-ray crystallography
Groenewegen, P.P.M.; Feil, D.
1969-01-01
The calculation of molecular form factors from ab initio molecular electronic wavefunctions is discussed, and a scheme for application to X-ray diffraction structure analysis is given. The method is used to calculate the form factor of the NH+4 molecular ion from three accurate molecular
Surface sensitivity of nuclear-knock-out form factors
Fratamico, G.
1984-01-01
A numerical calculation has been performed to investigate the sensitivity of nuclear-knock-out form factors to nuclear-surface behaviour of bound-state wave functions. The result of our investigation suggests that one can extract the bound-state behaviour at the surface from experimental information on nuclear-knock-out form factors
Analytic properties of form factors in strictly confining models
Csikor, F.
1979-12-01
An argument is presented showing that strict confinement implies the possible existence of an (unwanted) branch point at q 2 =0 in the form factors. In case of a bag extended to infinity in the relative time, the branch point is certainly there (provided that the form factor is non zero at q 2 =0). (author)
bin Pet, Mokhtar; Sihes, Ahmad Johari Hj
2015-01-01
This study aims to examine the external factors of form six teachers who can influence thinking domain form six teachers in their teaching. This study was conducted using a quantitative approach using questionnaires. A total of 300 form six teacher schools in Johor were chosen as respondents. The findings were obtained as student background…
Symmetry Breaking and transition form factors from {eta} and {omega} decays
Roy, Ankhi, E-mail: ankhi@iiti.ac.in [IIT Indore (India); Collaboration: WASA-at-COSY Collaboration
2013-03-15
The WASA-at-COSY collaboration uses meson production and the decays for the realization of the physics goals. Different rare decay channels of the mesons have to be analyzed in order to investigate symmetry breaking patterns. The combination of high intensity COSY (COoler SYnchrotron) beams and the WASA 4{pi} detector setup allows us to study the rare decay channels of light mesons. We are analyzing different symmetry breaking decay channels of {eta} mesons. One rare decay channel {eta}{yields}{pi}{sup + }{pi}{sup -} e{sup + }e{sup -} is being used to test CP violation. The asymmetry in the angle between the electron and pion planes can give insight about the degree of CP violation. The study of another rare decay channel {eta}{yields}{pi}{sup 0}e{sup + }e{sup -} is a test of C-parity violation. Our analysis of transition form factors of different mesons via conversion decays ({eta}{yields}{gamma}{gamma}{sup *}{yields}e{sup + }e{sup -} {gamma}, {omega}{yields}{pi}{sup 0}e{sup + }e{sup -}) provides insight about hadron structure. The transition form-factor of the {omega} meson provides information about the form factor in the time-like region where the two vector particles (the {omega} and the intermediate virtual photon) have an invariant mass squared will be discussed.
Alarcón, J. M.; Weiss, C.
2018-05-01
We study the nucleon electromagnetic form factors (EM FFs) using a recently developed method combining chiral effective field theory (χ EFT ) and dispersion analysis. The spectral functions on the two-pion cut at t >4 Mπ2 are constructed using the elastic unitarity relation and an N /D representation. χ EFT is used to calculate the real functions J±1(t ) =f±1(t ) /Fπ(t ) (ratios of the complex π π →N N ¯ partial-wave amplitudes and the timelike pion FF), which are free of π π rescattering. Rescattering effects are included through the empirical timelike pion FF | Fπ(t) | 2 . The method allows us to compute the isovector EM spectral functions up to t ˜1 GeV2 with controlled accuracy (leading order, next-to-leading order, and partial next-to-next-to-leading order). With the spectral functions we calculate the isovector nucleon EM FFs and their derivatives at t =0 (EM radii, moments) using subtracted dispersion relations. We predict the values of higher FF derivatives, which are not affected by higher-order chiral corrections and are obtained almost parameter-free in our approach, and explain their collective behavior. We estimate the individual proton and neutron FFs by adding an empirical parametrization of the isoscalar sector. Excellent agreement with the present low-Q2 FF data is achieved up to ˜0.5 GeV2 for GE, and up to ˜0.2 GeV2 for GM. Our results can be used to guide the analysis of low-Q2 elastic scattering data and the extraction of the proton charge radius.
Mallik, Samirnath
2016-01-01
High energy laboratories are performing experiments in heavy ion collisions to explore the structure of matter at high temperature and density. This elementary book explains the basic ideas involved in the theoretical analysis of these experimental data. It first develops two topics needed for this purpose, namely hadron interactions and thermal field theory. Chiral perturbation theory is developed to describe hadron interactions and thermal field theory is formulated in the real-time method. In particular, spectral form of thermal propagators is derived for fields of arbitrary spin and used to calculate loop integrals. These developments are then applied to find quark condensate and hadron parameters in medium, including dilepton production. Finally, the non-equilibrium method of statistical field theory to calculate transport coefficients is reviewed. With technical details explained in the text and appendices, this book should be accessible to researchers as well as graduate students interested in thermal ...
Comments on electromagnetic form factors of the nucleon
Sachs, R.G.; Wali, K.C.
1989-01-01
This paper draws the concept of nucleon form factors further to consider the electromagnetic aspect based on the magnetic moment of the nucleon. These are seen as valid physical interpretations of form factors in electron-nucleon interactions. A linear combination of two functions, associated with charge radius, is derived, which agreed well with experimental results. The paper also expands the specific form to include relativistic cases and consider appropriate frames of reference. (UK)
Form factors in the projected linear chiral sigma model
Alberto, P.; Coimbra Univ.; Bochum Univ.; Ruiz Arriola, E.; Fiolhais, M.; Urbano, J.N.; Coimbra Univ.; Goeke, K.; Gruemmer, F.; Bochum Univ.
1990-01-01
Several nucleon form factors are computed within the framework of the linear chiral soliton model. To this end variational means and projection techniques applied to generalized hedgehog quark-boson Fock states are used. In this procedure the Goldberger-Treiman relation and a virial theorem for the pion-nucleon form factor are well fulfilled demonstrating the consistency of the treatment. Both proton and neutron charge form factors are correctly reproduced, as well as the proton magnetic one. The shapes of the neutron magnetic and of the axial form factors are good but their absolute values at the origin are too large. The slopes of all the form factors at zero momentum transfer are in good agreement with the experimental data. The pion-nucleon form factor exhibits to great extent a monopole shape with a cut-off mass of Λ=690 MeV. Electromagnetic form factors for the vertex γNΔ and the nucleon spin distribution are also evaluated and discussed. (orig.)
Exclusive hadron production in two photon reactions
Poppe, M.
1986-02-01
This paper summarises experimental results on exclusive hadron production in two photon collisions at electron positron storage rings and attempts some interpretation. Experimental know how is described and new suggestions are made for future analyses. New model calculations on resonance form factors and pair production amplitudes are presented. The two photon vertex is decomposed such that experiments can be parameterised with the minimal number of free parameters. Selection rules for off shell photon collisions are given in addition to Yang's theorems. (orig.)
Absorptive form factors for high-energy electron diffraction
Bird, D.M.; King, Q.A.
1990-01-01
The thermal diffuse scattering contribution to the absorptive potential in high-energy electron diffraction is calculated in the form of an absorptive contribution to the atomic form factor. To do this, the Einstein model of lattice vibrations is used, with isotropic Debye-Waller factors. The absorptive form factors are calculated as a function of scattering vector s and temperature factor M on a grid which enables polynomial interpolation of the results to be accurate to better than 2% for much of the ranges 0≤Ms 2 ≤6 and 0≤M≤2 A 2 . The computed values, together with an interpolation routine, have been incorporated into a Fortran subroutine which calculates both the real and absorptive form factors for 54 atomic species. (orig.)
Pseudoscalar form factors in tau-neutrino nucleon scattering
Hagiwara, K.; Mawatari, K.; Yokoya, H.
2004-01-01
We investigate the pseudoscalar transition form factors of nucleon for quasi-elastic scattering and Δ resonance production in tau-neutrino nucleon scattering via the charged current interactions. Although the pseudoscalar form factors play an important role for the τ production in neutrino-nucleon scattering, these are not known well. In this Letter, we examine their effects in quasi-elastic scattering and Δ resonance production and find that the cross section, Q 2 distribution, and spin polarization of the produced τ ± leptons are quite sensitive to the pseudoscalar form factors
Anomaly, mixing and transition form factors of pseudoscalar mesons
Klopot, Yaroslav; Oganesian, Armen; Teryaev, Oleg
2011-01-01
We derive the exact non-perturbative QCD sum rule for the transition form factors of η and η ′ using the dispersive representation of axial anomaly. This sum rule allows to express the transition form factors entirely in terms of meson decay constants. Using this sum rule several mixing schemes were analyzed and compared to recent experimental data. A good agreement with experimental data on η,η ′ transition form factors in the range from real to highly virtual photons was obtained.
Anomaly, mixing and transition form factors of pseudoscalar mesons
Klopot, Yaroslav, E-mail: klopot@theor.jinr.ru [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna 141980 (Russian Federation); Oganesian, Armen, E-mail: armen@itep.ru [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna 141980 (Russian Federation); Institute of Theoretical and Experimental Physics, B. Cheremushkinskaya 25, Moscow 117218 (Russian Federation); Teryaev, Oleg, E-mail: teryaev@theor.jinr.ru [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna 141980 (Russian Federation)
2011-10-15
We derive the exact non-perturbative QCD sum rule for the transition form factors of {eta} and {eta}{sup Prime} using the dispersive representation of axial anomaly. This sum rule allows to express the transition form factors entirely in terms of meson decay constants. Using this sum rule several mixing schemes were analyzed and compared to recent experimental data. A good agreement with experimental data on {eta},{eta}{sup Prime} transition form factors in the range from real to highly virtual photons was obtained.
Strange nucleon electromagnetic form factors from lattice QCD
Alexandrou, C.; Constantinou, M.; Hadjiyiannakou, K.; Jansen, K.; Kallidonis, C.; Koutsou, G.; Avilés-Casco, A. Vaquero
2018-05-01
We evaluate the strange nucleon electromagnetic form factors using an ensemble of gauge configurations generated with two degenerate maximally twisted mass clover-improved fermions with mass tuned to approximately reproduce the physical pion mass. In addition, we present results for the disconnected light quark contributions to the nucleon electromagnetic form factors. Improved stochastic methods are employed leading to high-precision results. The momentum dependence of the disconnected contributions is fitted using the model-independent z-expansion. We extract the magnetic moment and the electric and magnetic radii of the proton and neutron by including both connected and disconnected contributions. We find that the disconnected light quark contributions to both electric and magnetic form factors are nonzero and at the few percent level as compared to the connected. The strange form factors are also at the percent level but more noisy yielding statistical errors that are typically within one standard deviation from a zero value.
Infrared photons and gluons and the electromagnetic quark form factor
Scholz, B.
1982-01-01
A method for a consistent treatment of the infrared behaviour of QED and QCD is presented. As an application of the method the calculation of the electromagnetic quark form factor is discussed. (M.F.W.)
Finite volume form factors in the presence of integrable defects
Bajnok, Z.; Buccheri, F.; Hollo, L.; Konczer, J.; Takacs, G.
2014-01-01
We developed the theory of finite volume form factors in the presence of integrable defects. These finite volume form factors are expressed in terms of the infinite volume form factors and the finite volume density of states and incorporate all polynomial corrections in the inverse of the volume. We tested our results, in the defect Lee–Yang model, against numerical data obtained by truncated conformal space approach (TCSA), which we improved by renormalization group methods adopted to the defect case. To perform these checks we determined the infinite volume defect form factors in the Lee–Yang model exactly, including their vacuum expectation values. We used these data to calculate the two point functions, which we compared, at short distance, to defect CFT. We also derived explicit expressions for the exact finite volume one point functions, which we checked numerically. In all of these comparisons excellent agreement was found
The connected prescription for form factors in twistor space
Brandhuber, A.; Hughes, E.; Panerai, R.; Spence, B.; Travaglini, G. [Centre for Research in String Theory, School of Physics and Astronomy,Queen Mary University of London,Mile End Road, London E1 4NS (United Kingdom)
2016-11-23
We propose a connected prescription formula in twistor space for all tree-level form factors of the stress tensor multiplet operator in N=4 super Yang-Mills, which is a generalisation of the expression of Roiban, Spradlin and Volovich for superamplitudes. By introducing link variables, we show that our formula is identical to the recently proposed four-dimensional scattering equations for form factors. Similarly to the case of amplitudes, the link representation of form factors is shown to be directly related to BCFW recursion relations, and is considerably more tractable than the scattering equations. We also discuss how our results are related to a recent Grassmannian formulation of form factors, and comment on a possible derivation of our formula from ambitwistor strings.
Normalization Of Thermal-Radiation Form-Factor Matrix
Tsuyuki, Glenn T.
1994-01-01
Report describes algorithm that adjusts form-factor matrix in TRASYS computer program, which calculates intraspacecraft radiative interchange among various surfaces and environmental heat loading from sources such as sun.
Classical limit of diagonal form factors and HHL correlators
Bajnok, Zoltan [MTA Lendület Holographic QFT Group, Wigner Research Centre,H-1525 Budapest 114, P.O.B. 49 (Hungary); Janik, Romuald A. [Institute of Physics, Jagiellonian University,ul. Łojasiewicza 11, 30-348 Kraków (Poland)
2017-01-16
We propose an expression for the classical limit of diagonal form factors in which we integrate the corresponding observable over the moduli space of classical solutions. In infinite volume the integral has to be regularized by proper subtractions and we present the one, which corresponds to the classical limit of the connected diagonal form factors. In finite volume the integral is finite and can be expressed in terms of the classical infinite volume diagonal form factors and subvolumes of the moduli space. We analyze carefully the periodicity properties of the finite volume moduli space and found a classical analogue of the Bethe-Yang equations. By applying the results to the heavy-heavy-light three point functions we can express their strong coupling limit in terms of the classical limit of the sine-Gordon diagonal form factors.
Conformal symmetry and pion form factor: Soft and hard contributions
Choi, Ho-Meoyng; Ji, Chueng-Ryong
2006-01-01
We discuss a constraint of conformal symmetry in the analysis of the pion form factor. The usual power-law behavior of the form factor obtained in the perturbative QCD analysis can also be attained by taking negligible quark masses in the nonperturbative quark model analysis, confirming the recent AdS/CFT correspondence. We analyze the transition from soft to hard contributions in the pion form factor considering a momentum-dependent dynamical quark mass from an appreciable constituent quark mass at low momentum region to a negligible current quark mass at high momentum region. We find a correlation between the shape of nonperturbative quark distribution amplitude and the amount of soft and hard contributions to the pion form factor
ELECTROMAGENTIC FORM FACTORS OF THE PROTON AND NEUTRON
Griffy, T. A.; Hofstadter, R.; Hughes, E. B.; Janssens, T.; Yearian, M. R.
1963-06-15
Proton form factors in the four-momentum-transfer range q/sup 2/ = 4.6 to 32.0 f/sup -2/ and neutron form factors in the range q/sup 2/ = 2.5 to 10.0 f/ sup -2/ are measured by means of electron elastic scattering by protons and electron inelastic scattering by deuterons. (T.F.H.)
Low-energy analysis of the nucleon electromagnetic form factors
Kubis, Bastian.; Meissner, Ulf-G.
2001-01-01
We analyze the electromagnetic form factors of the nucleon to fourth order in relativistic baryon chiral perturbation theory. We employ the recently proposed infrared regularization scheme and show that the convergence of the chiral expansion is improved as compared to the heavy-fermion approach. We also discuss the inclusion of vector mesons and obtain an accurate description of all four-nucleon form factors for momentum transfer squared up to Q 2 ≅0.4 GeV 2
Hyperon decay form factors in chiral perturbation theory
Lacour, Andre; Kubis, Bastian; Meissner, Ulf-G.
2007-01-01
We present a complete calculation of the SU(3)-breaking corrections to the hyperon vector form factors up to O(p 4 ) in covariant baryon chiral perturbation theory. Partial higher-order contributions are obtained, and we discuss chiral extrapolations of the vector form factor at zero momentum transfer. In addition we derive low-energy theorems for the subleading moments in hyperon decays, the weak Dirac radii and the weak anomalous magnetic moments, up to O(p 4 )
Form factors and other measures of strangeness in the nucleon
Diehl, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Feldmann, T. [Siegen Univ. (Germany). Theoretische Physik I; Kroll, P. [Bergische Univ., Wuppertal (Germany). Fachbereich Physik
2007-11-15
We discuss the phenomenology of strange-quark dynamics in the nucleon, based on experimental and theoretical results for electroweak form factors and for parton densities. In particular, we construct a model for the generalized parton distribution that relates the asymmetry s(x)- anti s(x) between the longitudinal momentum distributions of strange quarks and antiquarks with the form factor F{sup s}{sub 1}(t), which describes the distribution of strangeness in transverse position space. (orig.)
Form factors and other measures of strangeness in the nucleon
Diehl, M.; Feldmann, T.; Kroll, P.
2007-11-01
We discuss the phenomenology of strange-quark dynamics in the nucleon, based on experimental and theoretical results for electroweak form factors and for parton densities. In particular, we construct a model for the generalized parton distribution that relates the asymmetry s(x)- anti s(x) between the longitudinal momentum distributions of strange quarks and antiquarks with the form factor F s 1 (t), which describes the distribution of strangeness in transverse position space. (orig.)
From quarks and gluons to baryon form factors.
Eichmann, Gernot
2012-04-01
I briefly summarize recent results for nucleon and [Formula: see text] electromagnetic, axial and transition form factors in the Dyson-Schwinger approach. The calculation of the current diagrams from the quark-gluon level enables a transparent discussion of common features such as: the implications of dynamical chiral symmetry breaking and quark orbital angular momentum, the timelike structure of the form factors, and their interpretation in terms of missing pion-cloud effects.
Anon.
1986-01-01
The European Hadron Facility (EHF) is a project for particle and nuclear physics in the 1990s which would consist of a fast cycling high intensity proton synchrotron of about 30 GeV primary energy and providing a varied spectrum of intense high quality secondary beams (polarized protons, pions, muons, kaons, antiprotons, neutrinos). The physics case of this project has been studied over the last two years by a European group of particle and nuclear physicists (EHF Study Group), whilst the conceptual design for the accelerator complex was worked out (and is still being worked on) by an international group of machine experts (EHF Design Study Group). Both aspects have been discussed in recent years in a series of working parties, topical seminars, and workshops held in Freiburg, Trieste, Heidelberg, Karlsruhe, Les Rasses and Villigen. This long series of meetings culminated in the International Conference on a European Hadron Facility held in Mainz from 10-14 March
Lipatov, A.V. [Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); Joint Institute for Nuclear Research, Dubna (Russian Federation); Baranov, S.P. [P.N. Lebedev Physical Institute, Moscow (Russian Federation); Jung, H. [Deutsches Elektronen-Synchrotron, Hamburg (Germany); Malyshev, M.A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation)
2018-01-15
We consider the production of J/ψ and ψ(2S) mesons originating from the decays of b-flavored hadrons at the LHC using the k{sub T}-factorization approach. Our analysis covers both inclusive charmonia production and production of J/ψ mesons in association with Z bosons. We apply the transverse momentum dependent (or unintegrated) gluon density in a proton derived from Catani-Ciafaloni-Fiorani-Marchesini (CCFM) evolution equation and adopt fragmentation functions based on the non-relativistic QCD factorization to describe the inclusive b-hadron decays into the different charmonium states. Our predictions agree well with latest experimental data taken by the CMS, ATLAS and LHCb Collaborations at √(s) = 7, 8 and 13 TeV. The contributions from double parton scattering to the associated non-prompt J/ψ + Z production are estimated and found to be small. (orig.)
Form factors of the finite quantum XY-chain
Iorgov, Nikolai
2011-01-01
Explicit factorized formulas for the matrix elements (form factors) of the spin operators σ x and σ y between the eigenvectors of the Hamiltonian of the finite quantum periodic XY-chain in a transverse field were derived. The derivation is based on the relations between three models: the model of quantum XY-chain, Ising model on 2D lattice and N = 2 Baxter-Bazhanov-Stroganov τ (2) -model. Due to these relations we transfer the formulas for the form factors of the latter model recently obtained by the use of separation of variables method to the model of quantum XY-chain. Hopefully, the formulas for the form factors will help in analysis of multipoint dynamic correlation functions at a finite temperature. As an example, we re-derive the asymptotics of the two-point correlation function in the disordered phase without the use of the Toeplitz determinants and the Wiener-Hopf factorization method.
Current algebra constraints on K13 form factors
Simmons, L.D.
1975-01-01
New theoretical constraints on the divergence form factor in K 13 decays are derived. The assumptions underlying the derivation are presented. The constraints on the divergence form factor are derived and summarized in the form of a theorem. It is shown that the finiteness of the leakage charge is a natural consequence of the parallelΔI vectorparallel = 1 / 2 rule. The Lorentz invariance of current algebra sum rules is discussed. The theorem is rederived within the context of the conserved vector current hypothesis. Finally, the implications of the present work are noted with attention being paid to both the theoretical and experimental consequences
Describing the nucleon electromagnetic form factors at high momentum transfers
Theussl, L.; Desplanques, B.; Silvestre-Brac, B.; Varga, K.
1999-01-01
Electromagnetic form factors of the nucleon are calculated within the framework of a non-relativistic constituent-quark model. The emphasis is put on the reliability and accuracy of present day numerical methods used to solve the three-body problem. The high-q 2 behaviour of the form factors is determined by the form of the wave function at short distances and, due to the small absolute values that one deals with, an accurate solution is essential. Refs. 5, figs. 2 (author)
Semileptonic Form Factor ratio Bs → Ds/B → D and Its Application to BR(Bs0 → μ+μ-)
Du, Daping; DeTar, Carleton; Kronfeld, Andreas; Laiho, Jack; Meurice, Yannick; Qiu, Si-wei
2011-01-01
We present a (2+1)-flavor lattice QCD calculation of the form factor ratio between the semileptonic decays (bar B) s 0 → D s + l - (bar ν) and (bar B) 0 → D + l - (bar ν). This ratio is an important theoretical input to the hadronic determination of the B meson fragmentation fraction ratio f s /f d which enters in the measurement of BR(B s 0 → μ + μ - ). Small lattice spacings and high statistics enable us to simulate the decays with a dynamic final D meson of small momentum and reliably extract the hadronic matrix elements at nonzero recoil. We report our preliminary result for the form factor ratio at the corresponding momentum transfer of the two decays f 0 (s) (M π 2 )/f 0 (d) (M K 2 ).
The impact of s- anti s asymmetry on the strange electromagnetic form factor
Ghasempour Nesheli, Ali [Islamic Azad University, Department of Physics, Shiraz Branch, Shiraz (Iran, Islamic Republic of)
2016-09-15
The existence of the strange quark asymmetry in the nucleon sea has been indicated by both the experimental and theoretical analyses. Although it is well known that the s- anti s asymmetry is important for some processes in high-energy hadron collisions, it has also been indicated that it can be related to the strange Dirac form factor F{sub 1}{sup s}. In this work, we have studied the impact of s- anti s asymmetry and its uncertainty from various modern parton distribution functions (PDFs) on F{sub 1} {sup s} and compared the obtained results with the available experimental information. As a result, we found that the uncertainty in F{sub 1}{sup s}(t) due to the s(x) - anti s (x) distribution is rather large so that it dominates the model uncertainty at all values of the squared momentum transfer t. However, taking into account the uncertainties, the theoretical predictions of F{sub 1}{sup s}(t) are fully compatible with the estimate extracted from experiment. We concluded that the future accurate experimental data of the strange Dirac form factor might be used to put direct constraints on the strange content of the proton and reduce its uncertainty that has always been a challenge. (orig.)
B→π form factor with 2 flavours of O(a) improved Wilson quarks
Bahr, Felix; Bernardoni, Fabio; Ramos, Alberto; Simma, Hubert; Sommer, Rainer; Bulava, John
2012-10-01
The determinations of vertical stroke V ub vertical stroke from the exclusive branching ratios of B→τν and B→πlν tend to show a tension at the level of 3σ. On the theoretical side they depend on the lattice computation of the hadronic matrix elements f B and the B →>π form factor f + (q 2 ). To understand the tension, improved precision and a careful analysis of the systematics involved are necessary. Working towards this goal, we present preliminary lattice results of the ALPHA collaboration for the B→ π form factor f + (q 2 ) with N f =2 flavours of O(a)-improved Wilson fermions. Our computation uses HQET in the static limit, pion masses ranging down to ∼250 MeV, large volumes with m π L>4, three lattice spacings, and non-perturbative renormalization. We describe the techniques adopted to reduce the statistical noise (stochastic all-to-all with full time dilution) and the contamination from excited states (smearing for the B and the pion). We estimate the size of the chiral and continuum extrapolations. We discuss the impact our result could have to clarify the above mentioned discrepancy in the determination of vertical stroke V ub vertical stroke.
Towards a Resolution of the Proton Form Factor Problem: New Electron and Positron Scattering Data
Adikaram, D.; Rimal, D.; Weinstein, L. B.; Raue, B.; Khetarpal, P.; Bennett, R. P.; Arrington, J.; Brooks, W. K.; Adhikari, K. P.; Afanasev, A. V.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Carman, D. S.; Careccia, S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dodge, G. E.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Filippi, A.; Fleming, J. A.; Fradi, A.; Garillon, B.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guegan, B.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joo, K.; Joosten, S.; Kalantarians, N.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mattione, P.; Mayer, M.; McKinnon, B.; Mestayer, M. D.; Meyer, C. A.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moody, C. I.; Moutarde, H.; Movsisyan, A.; Camacho, C. Munoz; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Peña, C.; Pisano, S.; Pogorelko, O.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Simonyan, A.; Skorodumina, I.; Smith, E. S.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Stoler, P.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tian, Ye; Trivedi, A.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration
2015-02-01
There is a significant discrepancy between the values of the proton electric form factor, GEp, extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of GEp from the unpolarized electron-proton cross sections. We determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections using a simultaneous, tertiary electron-positron beam incident on a liquid hydrogen target and detecting the scattered particles in the Jefferson Lab CLAS detector. This novel technique allowed us to cover a wide range in virtual photon polarization (ɛ ) and momentum transfer (Q2) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing ɛ at Q2=1.45 GeV2 . This measurement is consistent with the size of the form factor discrepancy at Q2≈1.75 GeV2 and with hadronic calculations including nucleon and Δ intermediate states, which have been shown to resolve the discrepancy up to 2 - 3 GeV2 .
Overview of factors affecting the leachability of nuclear waste forms
Stone, J.A.
1980-01-01
An overview of various factors that affect the leachability of nuclear waste forms is presented. The factors affect primarily the leaching system (temperature, for example), the leachant (pH, for example), or the solid being leached (surface condition, for example). A qualitative understanding exists of the major factors affecting leaching, but further studies are needed to establish leaching mechanisms and develop predictive models. 67 refs
Fundamentals in hadronic atom theory
Deloff, A
2003-01-01
Hadronic atoms provide a unique laboratory for studying hadronic interactions essentially at threshold. This text is the first book-form exposition of hadronic atom theory with emphasis on recent developments, both theoretical and experimental. Since the underlying Hamiltonian is a non-self-adjoined operator, the theory goes beyond traditional quantum mechanics and this book covers topics that are often glossed over in standard texts on nuclear physics. The material contained here is intended for the advanced student and researcher in nuclear, atomic or elementary-particle physics. A good know
Hadronic vacuum polarization in true muonium
Lamm, Henry
2017-01-01
In order to reduce the theoretical uncertainty in the prediction, the leading-order hadronic vacuum polarization contribution to the hyperfine splitting of true muonium is reevaluated in two ways. A more complex pionic form factor and better estimates of the perturbative QCD contributions are used to study the model dependence of the previous calculation. The second, more accurate method directly integrates the Drell ratio R (s ) to obtain C1 ,HVP=-0.04874 (9 ) . This corresponds to an energy shift in the hyperfine splitting (HFS) of Δ EHFS,HVP μ=-8202 (16 ) MHz and represents a factor-of-50 reduction in the theoretical uncertainty from hadronic sources. We also compute the contribution in positronium, which is too small at present to detect.
Simulation of soft hadron hadron collisions at ultrarelativistic energies
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
Towards the physical point hadronic vacuum polarisation from Moebius DWF
Marinkovic, Marina; Del Debbio, Luigi; Juettner, Andreas; Maltman, Kim; Portelli, Antonin
2015-01-01
We present steps towards the computation of the leading-order hadronic contribution to the muon anomalous magnetic moment on RBC/UKQCD physical point DWF ensembles. We discuss several methods for controlling and reducing uncertainties associated to the determination of the HVP form factor.
Dispersion-theoretical analysis of the nucleon electromagnetic form factors
Belushkin, M.
2007-09-29
The structure of the proton and the neutron is of fundamental importance for the study of the strong interaction dynamics over a wide range of momentum transfers. The nucleon form factors encode information on the internal structure of the nucleon as probed by the electromagnetic interaction, and, to a certain extent, reflect the charge and magnetisation distributions within the proton and the neutron. In this thesis we report on our investigation of the electromagnetic form factors of the proton and the neutron with dispersion relation techniques, including known experimental input on the {pi}{pi}, K anti K and the {rho}{pi} continua and perturbative QCD constraints. We include new experimental data on the pion form factor and the nucleon form factors in our simultaneous analysis of all four form factors in both the space- and the timelike regions for all momentum transfers, and perform Monte- Carlo sampling in order to obtain theoretical uncertainty bands. Finally, we discuss the implications of our results on the pion cloud of the nucleon, the nucleon radii and the Okubo-Zweig-Iizuka rule, and present our results of a model-independent approach to estimating two-photon effects in elastic electron-proton scattering. (orig.)
Dispersion-theoretical analysis of the nucleon electromagnetic form factors
Belushkin, M.
2007-01-01
The structure of the proton and the neutron is of fundamental importance for the study of the strong interaction dynamics over a wide range of momentum transfers. The nucleon form factors encode information on the internal structure of the nucleon as probed by the electromagnetic interaction, and, to a certain extent, reflect the charge and magnetisation distributions within the proton and the neutron. In this thesis we report on our investigation of the electromagnetic form factors of the proton and the neutron with dispersion relation techniques, including known experimental input on the ππ, K anti K and the ρπ continua and perturbative QCD constraints. We include new experimental data on the pion form factor and the nucleon form factors in our simultaneous analysis of all four form factors in both the space- and the timelike regions for all momentum transfers, and perform Monte- Carlo sampling in order to obtain theoretical uncertainty bands. Finally, we discuss the implications of our results on the pion cloud of the nucleon, the nucleon radii and the Okubo-Zweig-Iizuka rule, and present our results of a model-independent approach to estimating two-photon effects in elastic electron-proton scattering. (orig.)
Bunce, G.
1984-01-01
Is all hadronic physics ultimately describable by QCD. Certainly, many disparate phenomena can be understood within the QCD framework. Also certainly, there are important questions which are open, both theoretically (little guidance, as yet) and experimentally, regarding confinement. Are there dibaryons, baryonium, glueballs. In addition, there are experimental results which at present do not have an explanation. This talk, after a short section on QCD successes and difficulties, will emphasize two experimental topics which have recent results - glueball spectroscopy and exclusive reactions at large momentum transfer. Both are experimentally accessible in the AGS/LAMPF II/AGS II/TRIUMF II/SIN II energy domain
Juettner Fernandes, Bonnie
2014-01-01
What really happened during the Big Bang? Why did matter form? Why do particles have mass? To answer these questions, scientists and engineers have worked together to build the largest and most powerful particle accelerator in the world: the Large Hadron Collider. Includes glossary, websites, and bibliography for further reading. Perfect for STEM connections. Aligns to the Common Core State Standards for Language Arts. Teachers' Notes available online.
Buskulic, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Lucotte, A.; Minard, M.-N.; Nief, J.-Y.; Odier, P.; Pietrzyk, B.; Casado, M. P.; Chmeissani, M.; Comas, P.; Crespo, J. M.; Delfino, M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Juste, A.; Martinez, M.; Orteu, S.; Padilla, C.; Park, I. C.; Pascual, A.; Perlas, J. A.; Riu, I.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; de Palma, M.; Gelao, G.; Girone, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Marinelli, N.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; 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.; Alemany, R.; Bazarko, A. O.; Bright-Thomas, P.; Cattaneo, M.; Cerutti, F.; Coyle, P.; Drevermann, H.; Forty, R. W.; Frank, M.; Hagelberg, R.; Harvey, J.; Janot, P.; Jost, B.; Kneringer, E.; Knobloch, J.; Lehraus, I.; Lutters, G.; Mato, P.; Minten, A.; Miquel, R.; Mir, Ll. M.; Moneta, L.; Oest, T.; Pacheco, A.; Pusztaszeri, J.-F.; Ranjard, F.; Rensing, P.; Rizzo, G.; Rolandi, L.; Schlatter, D.; Schmelling, M.; Schmitt, M.; Schneider, O.; Tejessy, W.; Tomalin, I. R.; Venturi, A.; Wachsmuth, H.; Wagner, A.; Ajaltouni, Z.; Barrès, A.; Boyer, C.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Rosnet, P.; Rossignol, J.-M.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Nilsson, B. S.; Rensch, B.; Wäänänen, A.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Rougé, A.; Rumpf, M.; Valassi, A.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Focardi, E.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Jaffe, D. E.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Casper, D.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Curtis, L.; Dorris, S. J.; Halley, A. W.; Knowles, I. G.; Lynch, J. G.; O'Shea, V.; Raine, C.; Scarr, J. M.; Smith, K.; Teixeira-Dias, P.; Thompson, A. S.; Thomson, E.; Thomson, F.; Turnbull, R. M.; Becker, U.; Geweniger, C.; Graefe, G.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E. E.; Putzer, A.; Schmidt, M.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, S.; Wunsch, M.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Dornan, P. J.; Martin, E. B.; Moutoussi, A.; Nash, J.; Sedgbeer, J. K.; Stacey, A. M.; Williams, M. D.; Dissertori, G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Betteridge, A. P.; Bowdery, C. K.; Colrain, P.; Crawford, G.; Finch, A. J.; Foster, F.; Hughes, G.; Sloan, T.; Williams, M. I.; Galla, A.; Giehl, I.; Greene, A. M.; Hoffmann, C.; Jakobs, K.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.-G.; van Gemmeren, P.; Zeitnitz, C.; Aubert, J. J.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Diaconu, C.; Etienne, F.; Konstantinidis, N.; Payre, P.; Rousseau, D.; Talby, M.; Sadouki, A.; Thulasidas, M.; Trabelsi, K.; Aleppo, M.; Ragusa, F.; Berlich, R.; Blum, W.; Büscher, V.; Dietl, H.; Dydak, F.; Ganis, G.; Gotzhein, C.; Kroha, H.; Lütjens, G.; Lutz, G.; Männer, W.; Moser, H.-G.; Richter, R.; Rosado-Schlosser, A.; Schael, S.; Settles, R.; Seywerd, H.; St. Denis, R.; Stenzel, H.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Choi, Y.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Höcker, A.; Jacholkowska, A.; Jacquet, M.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Nikolic, I.; Park, H. J.; Schune, M.-H.; Simion, S.; Veillet, J.-J.; Videau, I.; Zerwas, D.; Azzurri, P.; Bagliesi, G.; Batignani, G.; Bettarini, S.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; dell'Orso, R.; Fantechi, R.; Ferrante, I.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Sanguinetti, G.; Sciabà, A.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Vannini, C.; Verdini, P. G.; Blair, G. A.; Bryant, L. M.; Chambers, J. T.; Gao, Y.; Green, M. G.; Medcalf, T.; Perrodo, P.; Strong, J. A.; von Wimmersperg-Toeller, J. H.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Maley, P.; Norton, P. R.; Thompson, J. C.; Wright, A. E.; Bloch-Devaux, B.; Colas, P.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.-F.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Black, S. N.; Dann, J. H.; Johnson, R. P.; Kim, H. Y.; Litke, A. M.; McNeil, M. A.; Taylor, G.; Booth, C. N.; Boswell, R.; Brew, C. A. J.; Cartwright, S.; Combley, F.; Koksal, A.; Letho, M.; Newton, W. M.; Reeve, J.; Thompson, L. F.; Böhrer, A.; Brandt, S.; Cowan, G.; Grupen, C.; Minguet-Rodriguez, J.; Rivera, F.; Saraiva, P.; Smolik, L.; Stephan, F.; Apollonio, M.; Bosisio, L.; della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Rothberg, J.; Wasserbaech, S.; Armstrong, S. R.; Elmer, P.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; González, S.; Grahl, J.; Greening, T. C.; Hayes, O. J.; Hu, H.; McNamara, P. A.; Nachtman, J. M.; Orejudos, W.; Pan, Y. B.; Saadi, Y.; Scott, I. J.; Walsh, A. M.; Walsh, J.; Sau, Lan Wu; Wu, X.; Yamartino, J. M.; Zheng, M.; Zobernig, G.
1997-02-01
Two samples of exclusive semileptonic decays, 579 B0 -> D*+l-νl events and 261 B0 -> D+l-νl events, are selected from approximately 3.9 million hadronic Z decays collected by the ALEPH detector at LEP. From the reconstructed differential decay rate of each sample, the product of the hadronic form factor F(ω) at zero recoil of the D(*)+ meson and the CKM matrix element Vcb are measured to be FD*+ (1) Vcb = (31.9 +/- 1.8stat +/- 1.9syst) × 10-3,FD+ (1) Vcb = (27.8 +/- 6.8stat +/- 6.5syst) × 10-3. The ratio of the form factorsFD+ (1) and FD*+ (1) is measured to beFD+ (1)/FD*+ (1) = 0.87 +/- 0.22stat +/- 0.21syst. A value of Vcb is extracted from the two samples, using theoretical constraints on the slope and curvature of the hadronic form factors and their normalization at zero recoil, with the result Vcb = (34.4 +/- 1.6stat +/- 2.3syst +/- 1.4th) × 10-3. The branching fractions are measured from the two integrated spectra to be Br(B0 -> D*+l-νl) = (5.53 +/- 0.26stat +/- 0.52syst) %, Br(B0 -> D+l-νl) = (2.35 +/- 0.20stat +/- 0.44syst) %.
Two-loop SL(2) form factors and maximal transcendentality
Loebbert, Florian; Sieg, Christoph; Wilhelm, Matthias; Yang, Gang
2016-01-01
Form factors of composite operators in the SL(2) sector of N=4 SYM theory are studied up to two loops via the on-shell unitarity method. The non-compactness of this subsector implies the novel feature and technical challenge of an unlimited number of loop momenta in the integrand’s numerator. At one loop, we derive the full minimal form factor to all orders in the dimensional regularisation parameter. At two loops, we construct the complete integrand for composite operators with an arbitrary number of covariant derivatives, and we obtain the remainder functions as well as the dilatation operator for composite operators with up to three covariant derivatives. The remainder functions reveal curious patterns suggesting a hidden maximal uniform transcendentality for the full form factor. Finally, we speculate about an extension of these patterns to QCD.
Two-body form factors at high Q2
Gross, F.; Keister, B.D.
1983-02-01
The charge form factor of a scalar deuteron at high momentum transfer is examined in a model employing scalar nucleons and mesons. With an eye toward establishing consistency criteria for more realistic calculations, several aspects of the model are examined in detail: the role of nucleon and meson singularities in the one-loop impulse diagram, the role of positive-and negative-energy nucleons, and the relationship to time-ordered perturbation theory. It is found that at large Q 2 (1) the form factor is dominated by a term in which the spectator nucleon is on the mass shell, and (2) the meson singularity structure of the d-n-p vertex function is unimportant in determining the overall high-Q 2 behaviour of the form factor
Computation of 3D form factors in complex environments
Coulon, N.
1989-01-01
The calculation of radiant interchange among opaque surfaces in a complex environment poses the general problem of determining the visible and hidden parts of the environment. In many thermal engineering applications, surfaces are separated by radiatively non-participating media and may be idealized as diffuse emitters and reflectors. Consenquently the net radiant energy fluxes are intimately related to purely geometrical quantities called form factors, that take into account hidden parts: the problem is reduced to the form factor evaluation. This paper presents the method developed for the computation of 3D form factors in the finite-element module of the system TRIO, which is a general computer code for thermal and fluid flow analysis. The method is derived from an algorithm devised for synthetic image generation. A comparison is performed with the standard contour integration method also implemented and suited to convex geometries. Several illustrative examples of finite-element thermal calculations in radiating enclosures are given
Two-loop SL(2) form factors and maximal transcendentality
Loebbert, Florian [Institut für Physik, Humboldt-Universität zu Berlin,Zum Großen Windkanal 6, 12489 Berlin (Germany); Sieg, Christoph [Institut für Physik, Humboldt-Universität zu Berlin,Zum Großen Windkanal 6, 12489 Berlin (Germany); Institut für Mathematik, Humboldt-Universität zu Berlin,Zum Großen Windkanal 6, 12489 Berlin (Germany); Wilhelm, Matthias [Institut für Physik, Humboldt-Universität zu Berlin,Zum Großen Windkanal 6, 12489 Berlin (Germany); Institut für Mathematik, Humboldt-Universität zu Berlin,Zum Großen Windkanal 6, 12489 Berlin (Germany); Niels Bohr Institute, Copenhagen University,Blegdamsvej 17, 2100 Copenhagen Ø (Denmark); Yang, Gang [CAS Key Laboratory of Theoretical Physics,Institute of Theoretical Physics, Chinese Academy of Sciences,Beijing 100190 (China); Institut für Physik, Humboldt-Universität zu Berlin,Zum Großen Windkanal 6, 12489 Berlin (Germany)
2016-12-19
Form factors of composite operators in the SL(2) sector of N=4 SYM theory are studied up to two loops via the on-shell unitarity method. The non-compactness of this subsector implies the novel feature and technical challenge of an unlimited number of loop momenta in the integrand’s numerator. At one loop, we derive the full minimal form factor to all orders in the dimensional regularisation parameter. At two loops, we construct the complete integrand for composite operators with an arbitrary number of covariant derivatives, and we obtain the remainder functions as well as the dilatation operator for composite operators with up to three covariant derivatives. The remainder functions reveal curious patterns suggesting a hidden maximal uniform transcendentality for the full form factor. Finally, we speculate about an extension of these patterns to QCD.
Electromagnetic form factors of the Ω- in lattice QCD
Alexandrou, C.; Korzec, T.; Koutsou, G.; Negele, J. W.; Proestos, Y.
2010-01-01
We present results on the omega baryon (Ω - ) electromagnetic form factors using N f =2+1 domain-wall fermion configurations for three pion masses in the range of about 350 to 300 MeV. We compare results obtained using domain-wall fermions with those of a mixed-action (hybrid) approach, which combines domain-wall valence quarks on staggered sea quarks, for a pion mass of about 350 MeV. We pay particular attention in the evaluation of the subdominant electric quadrupole form factor to sufficient accuracy to exclude a zero value, by constructing a sequential source that isolates it from the dominant form factors. The Ω - magnetic moment, μ Ω - , and the electric charge and magnetic radius, E0/M1 2 >, are extracted for these pion masses. The electric quadrupole moment is determined for the first time using dynamical quarks.
Evaluation of E2 form factor = 24Mg
Marinelli, J.R.; Moreira, J.R.
1988-11-01
Longitudinal and transverse electron scattering form factors for the 2 + state at 1.37 Mev of the 24 Mg nucleus was evaluated with rotational model wavefunctions. Four different approaches were used for the transverse E2 form factor: PHF, cranking model, ridig rotor and irrotational flow. For the nuclear intrinsic wavefunction, the Nilsson model was assumed in all approaches yielding the calculation of the form factor in PWBA and DWBA. The results are discussed and compared with a recent measurement performed with 180 0 electron scattered from this state. The DWBA calculation, taking into account first order corrections shows that PHF and irrotational flow models give the best agreements with the available data and compete in quality with more complex calculation performed under the 'shell model' approach. (author) [pt
Master integrals for the four-loop Sudakov form factor
Boels, Rutger; Kniehl, Bernd A.; Yang, Gang; Chinese Academy of Sciences, Beijing
2015-08-01
The light-like cusp anomalous dimension is a universal function in the analysis of infrared divergences. In maximally (N=4) supersymmetric Yang-Mills theory (SYM) in the planar limit, it is known, in principle, to all loop orders. The non-planar corrections are not known in any theory, with the first appearing at the four-loop order. Probably the simplest quantity which contains this correction is the four-loop two-point form factor of the stress tensor multiplet. This form factor was obtained in integrand form in a previous work for N=4 SYM, up to a single parameter. In this work, a reduction of the appearing integrals obtained by solving integration-by-parts (IBP) identities using (a tweaked version of) Reduze is reported. The form factor is shown to be independent of the remaining parameter at integrand level due to an intricate pattern of cancellations after IBP reduction. The appearing master integrals are cross-checked using algebraic techniques explored in the Mint package. The latter results provide the basis of master integrals applicable to generic form factors, including those in Quantum Chromodynamics. Remaining bottlenecks to completing the computation of the four-loop non-planar cusp anomalous dimension in N=4 SYM and beyond are identified.
Master integrals for the four-loop Sudakov form factor
Rutger H. Boels
2016-01-01
Full Text Available The light-like cusp anomalous dimension is a universal function in the analysis of infrared divergences. In maximally (N=4 supersymmetric Yang–Mills theory (SYM in the planar limit, it is known, in principle, to all loop orders. The non-planar corrections are not known in any theory, with the first appearing at the four-loop order. The simplest quantity which contains this correction is the four-loop two-point form factor of the stress tensor multiplet. This form factor was largely obtained in integrand form in a previous work for N=4 SYM, up to a free parameter. In this work, a reduction of the appearing integrals obtained by solving integration-by-parts (IBP identities using a modified version of Reduze is reported. The form factor is shown to be independent of the remaining parameter at integrand level due to an intricate pattern of cancellations after IBP reduction. Moreover, two of the integral topologies vanish after reduction. The appearing master integrals are cross-checked using independent algebraic-geometry techniques explored in the Mint package. The latter results provide the basis of master integrals applicable to generic form factors, including those in Quantum Chromodynamics. Discrepancies between explicitly solving the IBP relations and the MINT approach are highlighted. Remaining bottlenecks to completing the computation of the four-loop non-planar cusp anomalous dimension in N=4 SYM and beyond are identified.
Nucleon quark structure and strong meson-nucleon form factors
Efimov, G.V.; Ivanov, M.A.
1987-01-01
The nucleon is considered as a three-quark system in virton-quark model. The main statistic properties of proton and neutron are calculated: magnetic moments, electromagnetic radii, G A /G V ratio in weak neutron decay. Strong meson-nucleon form factors which determine nucleon-nucleon potential are obtained as a function of squared transfer momentum of mesons. The results are compared with phenomenological form factors used for description of phases of NN-scattering in the one-boson-, exchange model
Towards a dispersive determination of the pion transition form factor
Leupold, Stefan; Hoferichter, Martin; Kubis, Bastian; Niecknig, Franz; Schneider, Sebastian P.
2018-01-01
We start with a brief motivation why the pion transition form factor is interesting and, in particular, how it is related to the high-precision standard-model calculation of the gyromagnetic ratio of the muon. Then we report on the current status of our ongoing project to calculate the pion transition form factor using dispersion theory. Finally we present and discuss a wish list of experimental data that would help to improve the input for our calculations and/or to cross-check our results.
Towards a dispersive determination of the pion transition form factor
Leupold Stefan
2018-01-01
Full Text Available We start with a brief motivation why the pion transition form factor is interesting and, in particular, how it is related to the high-precision standard-model calculation of the gyromagnetic ratio of the muon. Then we report on the current status of our ongoing project to calculate the pion transition form factor using dispersion theory. Finally we present and discuss a wish list of experimental data that would help to improve the input for our calculations and/or to cross-check our results.
Measurement of the Charged Pion Electromagnetic Form Factor
J. Volmer; David Abbott; H. Anklin; Chris Armstrong; John Arrington; K. Assamagan; Steven Avery; Oliver K. Baker; Henk Blok; C. Bochna; Ed Brash; Herbert Breuer; Nicholas Chant; Jim Dunne; Tom Eden; Rolf Ent; David Gaskell; Ron Gilman; Kenneth Gustafsson; Wendy Hinton; Garth Huber; Hal Jackson; Mark K. Jones; Cynthia Keppel; P.H. Kim; Wooyoung Kim; Andi Klein; Doug Koltenuk; Meme Liang; George Lolos; Allison Lung; David Mack; D. McKee; David Meekins; Joseph Mitchell; H. Mkrtchian; B. Mueller; Gabriel Niculescu; Ioana Niculescu; D. Pitz; D. Potterveld; Liming Qin; Juerg Reinhold; I.K. Shin; Stepan Stepanyan; V. Tadevosian; L.G. Tang; R.L.J. van der Meer; K. Vansyoc; D. Van Westrum; Bill Vulcan; Stephen Wood; Chen Yan; W.X. Zhao; Beni Zihlmann
2001-01-01
Separated longitudinal and transverse structure functions for the reaction 1H(e,eprime pi+)n were measured in the momentum transfer region Q2=0.6-1.6 (GeV/c)**2 at a value of the invariant mass W=1.95 GeV. New values for the pion charge form factor were extracted from the longitudinal cross section by using a recently developed Regge model. The results indicate that the pion form factor in this region is larger than previously assumed and is consistent with a monopole parameterization fitted to very low Q2 elastic data
Deuteron form factor measurements at low momentum transfers
Schlimme B. S.
2016-01-01
Full Text Available A precise measurement of the elastic electron-deuteron scattering cross section at four-momentum transfers of 0.24 fm−1 ≤ Q ≤ 2.7 fm−1 has been performed at the Mainz Microtron. In this paper we describe the utilized experimental setup and the necessary analysis procedure to precisely determine the deuteron charge form factor from these data. Finally, the deuteron charge radius rd can be extracted from an extrapolation of that form factor to Q2 = 0.
The Nucleon Axial Form Factor and Staggered Lattice QCD
Meyer, Aaron Scott [Chicago U.
2017-01-01
The study of neutrino oscillation physics is a major research goal of the worldwide particle physics program over the upcoming decade. Many new experiments are being built to study the properties of neutrinos and to answer questions about the phenomenon of neutrino oscillation. These experiments need precise theoretical cross sections in order to access fundamental neutrino properties. Neutrino oscillation experiments often use large atomic nuclei as scattering targets, which are challenging for theorists to model. Nuclear models rely on free-nucleon amplitudes as inputs. These amplitudes are constrained by scattering experiments with large nuclear targets that rely on the very same nuclear models. The work in this dissertation is the rst step of a new initiative to isolate and compute elementary amplitudes with theoretical calculations to support the neutrino oscillation experimental program. Here, the eort focuses on computing the axial form factor, which is the largest contributor of systematic error in the primary signal measurement process for neutrino oscillation studies, quasielastic scattering. Two approaches are taken. First, neutrino scattering data on a deuterium target are reanalyzed with a model-independent parametrization of the axial form factor to quantify the present uncertainty in the free-nucleon amplitudes. The uncertainties on the free-nucleon cross section are found to be underestimated by about an order of magnitude compared to the ubiquitous dipole model parametrization. The second approach uses lattice QCD to perform a rst-principles computation of the nucleon axial form factor. The Highly Improved Staggered Quark (HISQ) action is employed for both valence and sea quarks. The results presented in this dissertation are computed at physical pion mass for one lattice spacing. This work presents a computation of the axial form factor at zero momentum transfer, and forms the basis for a computation of the axial form factor momentum dependence
On form factors and correlation functions in twistor space
Koster, Laura; Mitev, Vladimir; Staudacher, Matthias; Wilhelm, Matthias
2017-01-01
In this paper, we continue our study of form factors and correlation functions of gauge-invariant local composite operators in the twistor-space formulation of N=4 super Yang-Mills theory. Using the vertices for these operators obtained in our recent papers (DOI: 10.1103/PhysRevLett.117.011601; 10.1007/JHEP06(2016)162 ), we show how to calculate the twistor-space diagrams for general N k MHV form factors via the inverse soft limit, in analogy to the amplitude case. For general operators without α-dot indices, we then reexpress the NMHV form factors from the position-twistor calculation in terms of momentum twistors, deriving and expanding on a relation between the two twistor formalisms previously observed in the case of amplitudes. Furthermore, we discuss the calculation of generalized form factors and correlation functions as well as the extension to loop level, in particular providing an argument promised in https://www.doi.org/10.1002/prop.201400085.
Heavy quark form factors at two loops in perturbative QCD
Ablinger, J.; Schneider, C.; Behring, A.; Falcioni, G.
2017-11-01
We present the results for heavy quark form factors at two-loop order in perturbative QCD for different currents, namely vector, axial-vector, scalar and pseudo-scalar currents, up to second order in the dimensional regularization parameter. We outline the necessary computational details, ultraviolet renormalization and corresponding universal infrared structure.
Generation of truncated recombinant form of tumor necrosis factor ...
7. Original Research Article. Generation of truncated recombinant form of tumor necrosis factor ... as 6×His tagged using E.coli BL21 (DE3) expression system. The protein was ... proapoptotic signaling cascade through TNFR1. [5] which is ...
Pion form factor within QCD instanton vacuum model
Dorokhov, A.E.
1997-01-01
Instanton induced pion wave function is constructed. It provides an intrinsic k 1 dependence which suppress soft virtual one-gluon exchanges and thus legitimate the perturbative QCD (pQCD) calculations of the pion electromagnetic form factor in the region of momentum transfers above the scale. (author)
Form factors and charge radii in a quantum chromodynamics ...
tic form factors and charge radii of D, Ds,B,Bs and Bc mesons in a quantum chromodynamics. (QCD)-inspired ... as pointed out in [12,13], one can expect a similar success here too. .... 0 were large and the formalism failed to account for large ...
Numerical study of the lattice meson form factor
Woloshyn, R.M.; Kobos, A.M.
1986-01-01
The electric form factor of the pseudo-Goldstone meson (the generic pion) is calculated in quenched lattice quantum chromodynamics with SU(2) color. Charge radii are calculated for different values of the bare-quark mass. The results are in agreement with the physically reasonable expectation that heavier quarks have distributions of smaller radius
Measurement of the pion form factor at higher energies
Mack, D.J. [CEBAF, Newport News, VA (United States)
1994-04-01
One of the strongest arguments for increasing the nominal CEBAF beam energy to equal or exceed 6 GeV is that one would be able to make quality high Q{sup 2} measurements of the charged pion form factor.
Δ(1232) Axial Charge and Form Factors from Lattice QCD
Alexandrou, Constantia; Gregory, Eric B.; Korzec, Tomasz; Koutsou, Giannis; Negele, John W.; Sato, Toru; Tsapalis, Antonios
2011-01-01
We present the first calculation on the Δ axial vector and pseudoscalar form factors using lattice QCD. Two Goldberger-Treiman relations are derived and examined. A combined chiral fit is performed to the nucleon axial charge, N to Δ axial transition coupling constant and Δ axial charge.
On form factors and correlation functions in twistor space
Koster, Laura [Institut für Mathematik, Institut für Physik und IRIS Adlershof,Humboldt-Universität zu Berlin,Zum Großen Windkanal 6, 12489 Berlin (Germany); Mitev, Vladimir [PRISMA Cluster of Excellence, Institut für Physik, WA THEP,Johannes Gutenberg-Universität Mainz,Staudingerweg 7, 55128 Mainz (Germany); Staudacher, Matthias [Institut für Mathematik, Institut für Physik und IRIS Adlershof,Humboldt-Universität zu Berlin,Zum Großen Windkanal 6, 12489 Berlin (Germany); Wilhelm, Matthias [Niels Bohr Institute, Copenhagen University,Blegdamsvej 17, 2100 Copenhagen Ø (Denmark)
2017-03-24
In this paper, we continue our study of form factors and correlation functions of gauge-invariant local composite operators in the twistor-space formulation of N=4 super Yang-Mills theory. Using the vertices for these operators obtained in our recent papers (DOI: 10.1103/PhysRevLett.117.011601; 10.1007/JHEP06(2016)162 ), we show how to calculate the twistor-space diagrams for general N{sup k}MHV form factors via the inverse soft limit, in analogy to the amplitude case. For general operators without α-dot indices, we then reexpress the NMHV form factors from the position-twistor calculation in terms of momentum twistors, deriving and expanding on a relation between the two twistor formalisms previously observed in the case of amplitudes. Furthermore, we discuss the calculation of generalized form factors and correlation functions as well as the extension to loop level, in particular providing an argument promised in https://www.doi.org/10.1002/prop.201400085.
Heavy quark form factors at two loops in perturbative QCD
Ablinger, J.; Schneider, C. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation (RISC); Behring, A. [RWTH Aachen Univ. (Germany). Inst. fuer Theoretische Teilchenphysik und Kosmologie; Bluemlein, J.; Freitas, A. de; Marquard, P.; Rana, N. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Falcioni, G. [Nikhef, Amsterdam (Netherlands). Theory Group
2017-11-15
We present the results for heavy quark form factors at two-loop order in perturbative QCD for different currents, namely vector, axial-vector, scalar and pseudo-scalar currents, up to second order in the dimensional regularization parameter. We outline the necessary computational details, ultraviolet renormalization and corresponding universal infrared structure.
Nucleon form factors, generalized parton distributions and quark angular momentum
Diehl, Markus [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kroll, Peter [Bergische Univ., Wuppertal (Germany). Fachbereich Physik; Regensburg Univ. (Germany). Institut fuer Theoretische Physik
2013-02-15
We extract the individual contributions from u and d quarks to the Dirac and Pauli form factors of the proton, after a critical examination of the available measurements of electromagnetic nucleon form factors. From this data we determine generalized parton distributions for valence quarks, assuming a particular form for their functional dependence. The result allows us to study various aspects of nucleon structure in the valence region. In particular, we evaluate Ji's sum rule and estimate the total angular momentum carried by valence quarks at the scale {mu}=2 GeV to be J{sup u}{sub v}=0.230{sup +0.009}{sub -0.024} and J{sup d}{sub v}=-0.004{sup +0.010}{sub -0.016}.
Form factors and radiation widths of the giant multipole resonances
Denisov, V.Yu.
1990-01-01
Simple analytic relations for the form factors of inelastic electron scattering in the Born approximation and radiation widths of the isovector and isoscalar giant multipole resonances are derived. The dynamic relationship between the volume and surface density vibrations were taken into account in this calculation. The form factors in the Born approximation were found to be in satisfactory agreement with experimental data in the region of small transferred momenta. The radiation widths of isoscalar multipole resonances increase when the number of nucleons increase as A 1/3 , and for isovector resonances this dependence has the form f(A)A 1/3 , where f(A) is a slowly increasing function of A. Radiation widths well fit the experimental data
Nucleon form factors, generalized parton distributions and quark angular momentum
Diehl, Markus; Kroll, Peter; Regensburg Univ.
2013-02-01
We extract the individual contributions from u and d quarks to the Dirac and Pauli form factors of the proton, after a critical examination of the available measurements of electromagnetic nucleon form factors. From this data we determine generalized parton distributions for valence quarks, assuming a particular form for their functional dependence. The result allows us to study various aspects of nucleon structure in the valence region. In particular, we evaluate Ji's sum rule and estimate the total angular momentum carried by valence quarks at the scale μ=2 GeV to be J u v =0.230 +0.009 -0.024 and J d v =-0.004 +0.010 -0.016 .
Gupta, K.K.; Mitra, A.N.; Singh, N.N.
1990-01-01
A new relativistic definition of the reduced mass (μ 12 ) of a q bar q pair, so as to be in conformity with the standard Wightman-Garding definition of its relative four-momenta q μ , is introduced into the kernel of an ongoing Bethe-Salpeter (BS) program on a two-tier basis. The new definition of μ 12 (involving the hadron mass M) is found to produce a natural Regge asymptotic behavior (M 2 ∼N) in the hadron mass spectra, while retaining the property of an asymptotically linear (∼r) confinement in the three-dimensional structure of the BS kernel. The relativistic structure of μ 12 is responsible for a significant improvement in the fits to the ground-state masses of q bar q and Q bar q mesons as compared to its nonrelativistic definition m 1 m 2 /(m 1 +m 2 ). The leptonic decay constants f p and the charge radii thus calculated are also in excellent agreement with data (π,k) where available, while f p predictions for Q bar q mesons have good overlap with recent lattice predictions. Further, the scaling property (∼k μ -2 ) of the hadron's electromagnetic form factor at large k 2 is a consequence of the ''on-shell'' form of its null-plane wave function. All these results (which are indicated in the barest outline) are preceded by a perspective summary of the theoretical premises and practical working of the BS equation with a four-fermion interaction kernel as a necessary background on a two-tier basis
Unraveling hadron structure with generalized parton distributions
Andrei Belitsky; Anatoly Radyushkin
2004-10-01
The recently introduced generalized parton distributions have emerged as a universal tool to describe hadrons in terms of quark and gluonic degrees of freedom. They combine the features of form factors, parton densities and distribution amplitudes - the functions used for a long time in studies of hadronic structure. Generalized parton distributions are analogous to the phase-space Wigner quasi-probability function of non-relativistic quantum mechanics which encodes full information on a quantum-mechanical system. We give an extensive review of main achievements in the development of this formalism. We discuss physical interpretation and basic properties of generalized parton distributions, their modeling and QCD evolution in the leading and next-to-leading orders. We describe how these functions enter a wide class of exclusive reactions, such as electro- and photo-production of photons, lepton pairs, or mesons.
Superconformal Algebraic Approach to Hadron Structure
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.
Nuclear phenomena and the short distance structure of hadrons
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
The Factors of Forming the National HR-Management Model
Elena P. Kostenko
2017-12-01
Full Text Available There are some factors considered in this article, which influence the forming of national HR-management model. The group-forming criterion is the nature of factors, that determine the system of HR-management as a system of corporate culture values, norms and rules of organizational behavior, ways of realization some important managing functions and dominating approaches to make decisions. This article shows that the plurality of combinations in different factors leads to forming the unique HR-management model. The geoclimatic factor influences the principles of the labor organization (orientation primarily on individual or collective forms of labor, attitude to the management experience of other countries, attitude to resources, etc., the distribution of labor resources, the level of labor mobility, and the psychosocial type of employee. Models of man's labor behavior are constituted In the process of historical development. Attention is focused on the formation of a national HR-model, such as the conducted socio-economic policy, the characteristics of the institutional environment, economic goals and priorities of the country's development, the level of development and the nature of the national productive forces and economic structures. Much attention was paid to the analysis of the historically formed value system and labor traditions, which influence the approaches to HR-management. As far as religion influences the model of person’s inclusion in labor, motives of labor behavior, management culture of a certain employee, preferred payment etc., we examined how the main traditional religions (Christianity, Islam, Judaism, Buddhism, Confucianism, Hinduism influence the HR-management system in different countries.
Fixed target hadron production measurements
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...
Form factor of some types of toroidal solenoids
Koryavko, V.I.; Litvinenko, Yu.A.
1979-01-01
Obtained were the type of dependence between consumed power and formed field for toroidal helical-wound solenoids and the expression for the form factor analogous to the Fabry coefficient for cylindrical solenoids. Determined were optimum dimensions of the helical winding of ''forceless'' toroidal solenoids satisfying the condition of the formation of maximum field at minimum consumed power. Investigations also covered some types of conventional toroidal solenoids. Presented in the paper diagrams permitted to chose dimensions of the considered toroidal solenoids according to their consumed power and winding material volume
HERWIG for Hadron-Hadron physics
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
Measurement of weak meson form factors in spacelike regions
Brene, N
1973-01-01
With the construction of high energy, high intensity accelerators (NAL & CERN, SPS) investigation of neutrino scattering on virtual pions, a la Chew-Low, becomes experimentally possible. The process nu +N to mu /sup -/+K+ Delta is analysed to extract the usual K/sub l3/ form factor(s) for spacelike momentum transfer. A model calculation suggests that f/sub +/(T) can be determined reasonably well from a triple differential cross section, whereas only rough information on f /sub -/(T) may be obtained from the transverse polarization of the muon. The experiment proposed requires scanning of several millions of bubble chamber pictures. (14 refs).
Electromagnetic form factors and vertex constants for 6Li
Blokhintsev, L.D.; Shvarts, I.A.
1977-01-01
It has been assumed that the main contribution to the rapidly changing part of the charge form factor of 6 Li provides the amplitude of the triangle diagram containing virtual lines of deuteron and α particle. The vertex constant G 2 for the 6 Li→α+d decay is expressed through the nuclear charge radii for 6 Li, d, and α. Taking into account coulomb interaction in the vertex of the 6 Li→α+d reaction increases G 2 by about a factor of two. The account of virtuality of a deuteron cluster also leads to an increase in G 2
Revisiting the pion's scalar form factor in chiral perturbation theory
Juttner, Andreas
2012-01-01
The quark-connected and the quark-disconnected Wick contractions contributing to the pion's scalar form factor are computed in the two and in the three flavour chiral effective theory at next-to-leading order. While the quark-disconnected contribution to the form factor itself turns out to be power-counting suppressed its contribution to the scalar radius is of the same order of magnitude as the one of the quark-connected contribution. This result underlines that neglecting quark-disconnected contributions in simulations of lattice QCD can cause significant systematic effects. The technique used to derive these predictions can be applied to a large class of observables relevant for QCD-phenomenology.
SU(3) breaking in hyperon transition vector form factors
Shanahan, P.E.; Thomas, A.W.; Young, R.D.; Zanotti, J.M.; Rakow, P.E.L.
2015-08-01
We present a calculation of the SU(3)-breaking corrections to the hyperon transition vector form factors to O(p 4 ) in heavy baryon chiral perturbation theory with finite-range regularisation. Both octet and decuplet degrees of freedom are included. We formulate a chiral expansion at the kinematic point Q 2 =-(M B 1 -M B 2 ) 2 , which can be conveniently accessed in lattice QCD. The two unknown low-energy constants at this point are constrained by lattice QCD simulation results for the Σ - →n and Ξ 0 →Σ + transition form factors. Hence we determine lattice-informed values of f 1 at the physical point. This work constitutes progress towards the precise determination of vertical stroke V us vertical stroke from hyperon semileptonic decays.
Sine-Gordon breather form factors and quantum field equations
Babujian, H; Karowski, M
2002-01-01
Using the results of previous investigations on sine-Gordon form factors, exact expressions of all breather matrix elements are obtained for several operators: all powers of the fundamental Bose field, general exponentials of it, the energy-momentum tensor and all higher currents. Formulae for the asymptotic behaviour of bosonic form factors are presented which are motivated by Weinberg's power counting theorem in perturbation theory. It is found that the quantum sine-Gordon field equation holds, and an exact relation between the 'bare' mass and the renormalized mass is obtained. Also a quantum version of a classical relation for the trace of the energy-momentum is proved. The eigenvalue problem for all higher conserved charges is solved. All results are compared with perturbative Feynman graph expansions and full agreement is found
Nucleon form factors on the lattice with light dynamical fermions
Goeckeler, M.; Haegler, P.; Horsley, R.
2007-09-01
The electromagnetic form factors provide important insight into the internal structure of the nucleon and continue to be of major interest for experiment and phenomenology. For an intermediate range of momenta the form factors can be calculated on the lattice. However, the reliability of the results is limited by systematic errors mostly due to the required extrapolation to physical quark masses. Chiral effective field theories predict a rather strong quark mass dependence in a range which was yet inaccessible for lattice simulations. We give an update on recent results from the QCDSF collaboration using gauge configurations with dynamical N f =2, non-perturbatively O(a)-improved Wilson fermions at pion masses as low as 350 MeV. (orig.)
Nucleon form factors on the lattice with light dynamical fermions
Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Haegler, P. [Technische Univ. Muenchen, Garching (Germany). Inst. fuer Theoretische Physik T39; Horsley, R. [Edinburgh Univ. (GB). School of Physics] (and others)
2007-09-15
The electromagnetic form factors provide important insight into the internal structure of the nucleon and continue to be of major interest for experiment and phenomenology. For an intermediate range of momenta the form factors can be calculated on the lattice. However, the reliability of the results is limited by systematic errors mostly due to the required extrapolation to physical quark masses. Chiral effective field theories predict a rather strong quark mass dependence in a range which was yet inaccessible for lattice simulations. We give an update on recent results from the QCDSF collaboration using gauge configurations with dynamical N{sub f}=2, non-perturbatively O(a)-improved Wilson fermions at pion masses as low as 350 MeV. (orig.)
Quark-flavor mixing and the nucleon strangeness form factors
Ito, H.
1995-01-01
We have calculated the strangeness form factors of the nucleon G E s (Q), G M s (Q) and G A s (Q) and the electromagnetic form factors G E N (Q) as well, by using a relativistic constituent quark model of the nucleon wave function on the light-cone. Octet of Goldstone bosons (π, K, η) are assumed to induce the SU flavor mixing among the light constituent quarks; d-→K+s →d for example, and this mechanism induces the strangeness content in the nucleon. To calculate the meson-loop corrections to the electroweak couplings of constituent quarks, we have employed two models of the quark-meson vertex; (1) composite model of the Goldstone bosons (2) and (3) chiral quark Lagrangian. The loop momenta are regulated in a gauge-invariant way for both models
Generation of truncated recombinant form of tumor necrosis factor ...
Purpose: To produce truncated recombinant form of tumor necrosis factor receptor 1 (TNFR1), cysteine-rich domain 2 (CRD2) and CRD3 regions of the receptor were generated using pET28a and E. coli/BL21. Methods: DNA coding sequence of CRD2 and CRD3 was cloned into pET28a vector and the corresponding ...
Coverlayer fabrication for small form factor optical disks
Kim, Jong-Hwan; Lee, Seung-Won; Kim, Jin-Hong
2004-09-01
Two different coverlayers made of UV resin and coversheet were prepared for small form factor optical disks. Thin coverlayer of 10 mm and thick coverlayer of 80 mm were fabricated for flying optical head and non-flying optical head, respectively. Thickness uniformity was analyzed for both coverlayers, and new designs to diminish a ski-jump phenomenon were suggested. Mechanical properties of protective film made of UV resin were investigated.
Stackable Form-Factor Peripheral Component Interconnect Device and Assembly
Somervill, Kevin M. (Inventor); Ng, Tak-kwong (Inventor); Torres-Pomales, Wilfredo (Inventor); Malekpour, Mahyar R. (Inventor)
2013-01-01
A stackable form-factor Peripheral Component Interconnect (PCI) device can be configured as a host controller or a master/target for use on a PCI assembly. PCI device may comprise a multiple-input switch coupled to a PCI bus, a multiplexor coupled to the switch, and a reconfigurable device coupled to one of the switch and multiplexor. The PCI device is configured to support functionality from power-up, and either control function or add-in card function.
QCD constraints for the electromagnetic form factor of the pion
Machet, B.
1980-07-01
Using the modulus representation, we derive constraints for the behaviour of the electromagnetic form factor of the pion in the time like region [1 GeV 2 , + infinity[, from information given by perturbative QCD in the space like region [-μ 2 , - infinity[. A phenomenological μ dependent upper bound for the exponent of the first non leading logarithmic correction is deduced. Restrictions and problems of the method are discussed
Strong CP violation and the neutron electric dipole form factor
Kuckei, J.; Dib, C.; Faessler, A.; Gutsche, T.; Kovalenko, S. G.; Lyubovitskij, V. E.; Pumsa-ard, K.
2007-01-01
We calculate the neutron electric dipole form factor induced by the CP-violating θ term of QCD within a perturbative chiral quark model which includes pion and kaon clouds. On this basis, we derive the neutron electric dipole moment and the electron-neutron Schiff moment. From the existing experimental upper limits on the neutron electric dipole moment, we extract constraints on the θ parameter and compare our results with other approaches
Massive three-loop form factor in the planar limit
Henn, Johannes [PRISMA Cluster of Excellence, Johannes Gutenberg University,Staudingerweg 9, 55099 Mainz (Germany); Smirnov, Alexander V. [Research Computing Center, Moscow State University,119991 Moscow (Russian Federation); Smirnov, Vladimir A. [Skobeltsyn Institute of Nuclear Physics of Moscow State University,119991 Moscow (Russian Federation); Institut für Theoretische Teilchenphysik, Karlsruhe Institute of Technology (KIT),Wolfgang-Gaede Straße 1, 76128 Karlsruhe (Germany); Steinhauser, Matthias [Institut für Theoretische Teilchenphysik, Karlsruhe Institute of Technology (KIT),Wolfgang-Gaede Straße 1, 76128 Karlsruhe (Germany)
2017-01-17
We compute the three-loop QCD corrections to the massive quark-anti-quark-photon form factors F{sub 1} and F{sub 2} in the large-N{sub c} limit. The analytic results are expressed in terms of Goncharov polylogarithms. This allows for a straightforward numerical evaluation. We also derive series expansions, including power suppressed terms, for three kinematic regions corresponding to small and large invariant masses of the photon momentum, and small velocities of the heavy quarks.
Hadronic matrix elements in lattice QCD
Jaeger, Benjamin
2014-01-01
The lattice formulation of Quantum ChromoDynamics (QCD) has become a reliable tool providing an ab initio calculation of low-energy quantities. Despite numerous successes, systematic uncertainties, such as discretisation effects, finite-size effects, and contaminations from excited states, are inherent in any lattice calculation. Simulations with controlled systematic uncertainties and close to the physical pion mass have become state-of-the-art. We present such a calculation for various hadronic matrix elements using non-perturbatively O(a)-improved Wilson fermions with two dynamical light quark flavours. The main topics covered in this thesis are the axial charge of the nucleon, the electro-magnetic form factors of the nucleon, and the leading hadronic contributions to the anomalous magnetic moment of the muon. Lattice simulations typically tend to underestimate the axial charge of the nucleon by 5-10%. We show that including excited state contaminations using the summed operator insertion method leads to agreement with the experimentally determined value. Further studies of systematic uncertainties reveal only small discretisation effects. For the electro-magnetic form factors of the nucleon, we see a similar contamination from excited states as for the axial charge. The electro-magnetic radii, extracted from a dipole fit to the momentum dependence of the form factors, show no indication of finite-size or cutoff effects. If we include excited states using the summed operator insertion method, we achieve better agreement with the radii from phenomenology. The anomalous magnetic moment of the muon can be measured and predicted to very high precision. The theoretical prediction of the anomalous magnetic moment receives contribution from strong, weak, and electro-magnetic interactions, where the hadronic contributions dominate the uncertainties. A persistent 3σ tension between the experimental determination and the theoretical calculation is found, which is
In-Medium K^+ Electromagnetic Form Factor with a Symmetric Vertex in a Light Front Approach
Yabusaki, George H. S.; de Melo, J. P. B. C.; de Paula, Wayne; Tsushima, K.; Frederico, T.
2018-05-01
Using the light-front K^ +-Meson wave function based on a Bethe-Salpeter amplitude model for the Quark-Antiquark bound state, we study the Electromagnetic Form Factor (EMFF) of the K^ +-Meson in nuclear medium within the framework of light-front field theory. The K^ +-Meson model we adopt is well constrained by previous and recent studies to explain its properties in vacuum. The in-medium K^ +-Meson EMFF is evaluated for the plus-component of the electromagnetic current, J^+, in the Breit frame. In order to consistently incorporate the constituent up and antistrange Quarks of the K^ +-Meson immersed in symmetric nuclear matter, we use the Quark-Meson coupling model, which has been widely applied to various hadronic and nuclear phenomena in a nuclear medium with success. We predict the in-medium modification of the K^ +-Meson EMFF in symmetric nuclear matter. It is found that, after a fine tuning of the regulator mass, i.e. m_R = 0.600 GeV, the model is suitable to fit the available experimental data in vacuum within the theoretical uncertainties, and based on this we predict the in-medium modification of the K^ +-Meson EMFF.
Radyushkin, Anatoly V. [ODU, JLAB
2014-07-01
We outline basics of a new approach to transverse momentum dependence in hard processes. As an illustration, we consider hard exclusive transition process gamma*gamma -> to pi^0 at the handbag level. Our starting point is coordinate representation for matrix elements of operators (in the simplest case, bilocal O(0,z)) describing a hadron with momentum p. Treated as functions of (pz) and z^2, they are parametrized through a virtuality distribution amplitude (VDA) Phi (x, sigma), with x being Fourier-conjugate to (pz) and sigma Laplace-conjugate to z^2. For intervals with z^+=0, we introduce transverse momentum distribution amplitude (TMDA) Psi (x, k_\\perp), and write it in terms of VDA Phi (x, \\sigma). The results of covariant calculations, written in terms of Phi (x sigma) are converted into expressions involving Psi (x, k_\\perp. Starting with scalar toy models, we extend the analysis onto the case of spin-1/2 quarks and QCD. We propose simple models for soft VDAs/TMDAs, and use them for comparison of handbag results with experimental (BaBar and BELLE) data on the pion transition form factor. We also discuss how one can generate high-k_\\perp tails from primordial soft distributions.
Neutron charge radius and the neutron electric form factor
Gentile, T. R.; Crawford, C. B.
2011-01-01
For nearly forty years, the Galster parametrization has been employed to fit existing data for the neutron electric form factor, G E n , vs the square of the four-momentum transfer, Q 2 . Typically this parametrization is constrained to be consistent with experimental data for the neutron charge radius. However, we find that the Galster form does not have sufficient freedom to accommodate reasonable values of the radius without constraining or compromising the fit. In addition, the G E n data are now at sufficient precision to motivate a two-parameter fit (or three parameters if we include thermal neutron data). Here we present a modified form of a two-dipole parametrization that allows this freedom and fits both G E n (including recent data at both low and high four-momentum transfer) and the charge radius well with simple, well-defined parameters. Analysis reveals that the Galster form is essentially a two-parameter approximation to the two-dipole form but becomes degenerate if we try to extend it naturally to three parameters.
Relativistic form factors for clusters with nonrelativistic wave functions
Mitra, A.N.; Kumari, I.
1977-01-01
Using a simple variant of an argument employed by Licht and Pagnamenta (LP) on the effect of Lorentz contraction on the elastic form factors of clusters with nonrelativistic wave functions, it is shown how their result can be generalized to inelastic form factors so as to produce (i) a symmetrical appearance of Lorentz contraction effects in the initial and final states, and (ii) asymptotic behavior in accord with dimensional scaling theories. A comparison of this result with a closely analogous parametric form obtained by Brodsky and Chertok from a propagator chain model leads, with plausible arguments, to the conclusion of an effective mass M for the cluster, with M 2 varying as the number n of the quark constituents, instead of as n 2 . A further generalization of the LP formula is obtained for an arbitrary duality-diagram vertex, again with asymptotic behavior in conformity with dimensional scaling. The practical usefulness of this approach is emphasized as a complementary tool to those of high-energy physics for phenomenological fits to data up to moderate values of q 2
Joint resummation for pion wave function and pion transition form factor
Li, Hsiang-nan [Institute of Physics, Academia Sinica,Academia Rd., Taipei, Taiwan 115 (China); Department of Physics, National Cheng-Kung University,University Rd., Tainan, Taiwan 701 (China); Department of Physics, National Tsing-Hua University,Kuang-Fu Rd., Hsinchu, Taiwan 300 (China); Shen, Yue-Long [College of Information Science and Engineering, Ocean University of China,Songling Rd, Qingdao, Shandong 266100 (China); Wang, Yu-Ming [Institut für Theoretische Teilchenphysik und Kosmologie RWTH Aachen,Physikzentrum Otto-Blumenthal-Straße, D-52056 Aachen (Germany); Physik Department T31, Technische Universität München,James-Franck-Straße, D-85748 Garching (Germany)
2014-01-03
We construct an evolution equation for the pion wave function in the k{sub T} factorization formalism, whose solution sums the mixed logarithm ln xln k{sub T} to all orders, with x (k{sub T}) being a parton momentum fraction (transverse momentum). This joint resummation induces strong suppression of the pion wave function in the small x and large b regions, b being the impact parameter conjugate to k{sub T}, and improves the applicability of perturbative QCD to hard exclusive processes. The above effect is similar to those from the conventional threshold resummation for the double logarithm ln{sup 2} x and the conventional k{sub T} resummation for ln{sup 2} k{sub T}. Combining the evolution equation for the hard kernel, we are able to organize all large logarithms in the γ{sup ∗}π{sup 0}→γ scattering, and to establish a scheme-independent k{sub T} factorization formula. It will be shown that the significance of next-to-leading-order contributions and saturation behaviors of this process at high energy differ from those under the conventional resummations. It implies that QCD logarithmic corrections to a process must be handled appropriately, before its data are used to extract a hadron wave function. Our predictions for the involved pion transition form factor, derived under the joint resummation and the input of a non-asymptotic pion wave function with the second Gegenbauer moment a{sub 2}=0.05, match reasonably well the CLEO, BaBar, and Belle data.
Forms and factors of peer violence and victimisation
Dinić Bojana
2014-01-01
Full Text Available The main aim of this study was to explore the latent structure of violence and victimisation based on the factor analysis of the Peer Violence and Victimisation Questionnaire (PVVQ, as well as to examine the correlates of violence and victimisation. The sample included 649 secondary school students (61.8% male from the urban area. Besides the PVVQ, the Aggressiveness questionnaire AVDH was administered. Based on parallel analysis, three factors were extracted in the violence domain, as well as in the victimisation domain of the PVVQ. The factors were interpreted as a physical, verbal and relational form of violence and victimisation, which is in line with common classifications. The correlations of those forms with the aggressiveness dimensions were positive. The relationships with gender, school grade and school achievement referred to the importance of interaction effects between the mentioned characteristics of students and the tendency towards violence or being exposed to it. The main result is that boys from lower school grades and students with lower school achievement in general, are more prone to manifesting physical violence and more often are the target of physical violence. These groups of students are the target groups for preventive programs. The resulting effects indicated the complexity of the violence phenomenon and pointed to the need to consider the wider context of student’s characteristics in the determination of violence. [Projekat Ministarstva nauke Republike Srbije, br. 179037 i br. 179053
Dispersive analysis of the scalar form factor of the nucleon
Hoferichter, M.; Ditsche, C.; Kubis, B.; Meißner, U.-G.
2012-06-01
Based on the recently proposed Roy-Steiner equations for pion-nucleon ( πN) scattering [1], we derive a system of coupled integral equations for the π π to overline N N and overline K K to overline N N S-waves. These equations take the form of a two-channel Muskhelishvili-Omnès problem, whose solution in the presence of a finite matching point is discussed. We use these results to update the dispersive analysis of the scalar form factor of the nucleon fully including overline K K intermediate states. In particular, we determine the correction {Δ_{σ }} = σ ( {2M_{π }^2} ) - {σ_{{π N}}} , which is needed for the extraction of the pion-nucleon σ term from πN scattering, as a function of pion-nucleon subthreshold parameters and the πN coupling constant.
Baryon octet electromagnetic form factors in a confining NJL model
Manuel E. Carrillo-Serrano
2016-08-01
Full Text Available Electromagnetic form factors of the baryon octet are studied using a Nambu–Jona-Lasinio model which utilizes the proper-time regularization scheme to simulate aspects of colour confinement. In addition, the model also incorporates corrections to the dressed quarks from vector meson correlations in the t-channel and the pion cloud. Comparison with recent chiral extrapolations of lattice QCD results shows a remarkable level of consistency. For the charge radii we find the surprising result that rEp
Nucleon electromagnetic form factors in twisted mass lattice QCD
Alexandrou, C.; Jansen, K.; Korzec, T.; Humboldt Univ. Berlin
2011-02-01
We present results on the nucleon electromagnetic form factors within lattice QCD using two flavors of degenerate twisted mass fermions. Volume effects are examined using simulations at two volumes of spatial length L=2.1 fm and L=2.8 fm. Cut-off effects are investigated using three different values of the lattice spacings, namely a=0.089 fm, a=0.070 fm and a=0.056 fm. The nucleon magnetic moment, Dirac and Pauli radii are obtained in the continuum limit and chirally extrapolated to the physical pion mass allowing for a comparison with experiment. (orig.)
Nucleon electromagnetic form factors in twisted mass lattice QCD
Alexandrou, C.; Brinet, M.; Carbonell, J.; Harraud, P. A.; Papinutto, M.; Guichon, P.; Jansen, K.; Korzec, T.; Constantinou, M.
2011-01-01
We present results on the nucleon electromagnetic form factors within lattice QCD using two flavors of degenerate twisted mass fermions. Volume effects are examined using simulations at two volumes of spatial length L=2.1 fm and L=2.8 fm. Cutoff effects are investigated using three different values of the lattice spacings, namely a=0.089 fm, a=0.070 fm and a=0.056 fm. The nucleon magnetic moment, Dirac and Pauli radii are obtained in the continuum limit and chirally extrapolated to the physical pion mass allowing for a comparison with experiment.
Nucleon form factors with NF=2 twisted mass fermions
Alexandrou, C.; Korzec, T.; Brinet, M.; Carbonell, J.; Harraud, P.A.; Jansen, K.
2009-10-01
We present results on the electromagnetic and axial nucleon form factors using two degenerate flavors of twisted mass fermions on lattices of spatial size 2.1 fm and 2.7 fm and a lattice spacing of about 0.09 fm. We consider pion masses in the range of 260-470MeV.We chirally extrapolate results on the nucleon axial charge, the isovector Dirac and Pauli root mean squared radii and magnetic moment to the physical point and compare to experiment. (orig.)
Hadron structure with light dynamical quarks
Edwards, R.G.; Richards, D.G.; Fleming, G.T.; Haegler, P.; Negele, J.W.; Orginos, K.; Pochinsky, A.; Renner, D.B.; Schroers, W.
2005-09-01
Generalized parton distributions encompass a wealth of information concerning the three-dimensional quark and gluon structure of the nucleon, and thus provide an ideal focus for the study of hadron structure using lattice QCD. The special limits corresponding to form factors and parton distributions are well explored experimentally, providing clear tests of lattice calculations, and the lack of experimental data for more general cases provides opportunities for genuine predictions and for guiding experiment. We present results from hybrid calculations with improved staggered (Asqtad) sea quarks and domain wall valence quarks at pion masses down to 350 MeV. (orig.)
The pion form factor within the hidden local symmetry model
Benayoun, M.; David, P.; DelBuono, L.; Leruste, P.; O'Connell, H.B.
2003-01-01
We analyze a pion form factor formulation which fulfills the Analyticity requirement within the Hidden Local Symmetry (HLS) Model. This implies an s-dependent dressing of the ρ-γ VMD coupling and an account of several coupled channels. The corresponding function F π (s) provides nice fits of the pion form factor data from s=-0.25 to s=1 GeV 2 . It is shown that the coupling to KK has little effect, while ωπ 0 improves significantly the fit probability below the φ mass. No need for additional states like ρ(1450) shows up in this invariant-mass range. All parameters, except for the subtraction polynomial coefficients, are fixed from the rest of the HLS phenomenology. The fits show consistency with the expected behaviour of F π (s) at s=0 up to O(s 2 ) and with the phase shift data on δ 1 1 (s) from threshold to somewhat above the φ mass. The ω sector is also examined in relation with recent data from CMD-2. (orig.)
Small form factor optical fiber connector evaluation for harsh environments
Ott, Melanie N.; Thomes, W. Joe, Jr.; Chuska, Richard F.; Switzer, Robert; Blair, Diana E.
2011-09-01
For the past decade NASA programs have utilized the Diamond AVIM connector for optical fiber assemblies on space flight instrumentation. These connectors have been used in communications, sensing and LIDAR systems where repeatability and high performance are required. Recently Diamond has released a smaller form factor optical fiber connector called the "Mini-AVIM" which although more compact still includes the tight tolerances and the ratcheting feature of the heritage AVIM. NASA Goddard Space Flight Center Photonics Group in the Parts, Packaging and Assembly Technologies Office has been performing evaluations of this connector to determine how it compares to the performance of the AVIM connector and to assess its feasibility for harsh environmental applications. Vibration and thermal testing were performed on the Mini-AVIM with both multi-mode and single-mode optical fiber using insitu optical transmission monitoring. Random vibration testing was performed using typical launch condition profiles for most NASA missions but extended to 35 Grms, which is much higher than most requirements. Thermal testing was performed incrementally up to a range of -55°C to +125°C. The test results include both unjacketed fiber and cabled assembly evaluations. The data presented here indicate that the Mini-AVIM provides a viable option for small form factor applications that require a high performance optical fiber connector.
The Anomalous Process γπ → ππ and its Impact on the π0 Transition Form Factor
Kubis, Bastian
2014-12-01
The process γπ → ππ, in the limit of vanishing photon and pion energies, is determined by the chiral anomaly. This reaction can be investigated experimentally using Primakoff reactions, as currently done at COMPASS. We derive a dispersive representation that allows one to extract the chiral anomaly from cross-section measurements up to 1 GeV, where effects of the ρ resonance are included model-independently via the ππ P-wave phase shift. We discuss how this amplitude serves as an important input to a dispersion-theoretical analysis of the π0 transition form factor, which in turn is a vital ingredient to the hadronic light-by-light contribution to the anomalous magnetic moment of the muon.
Balek, Petr; The ATLAS collaboration
2016-01-01
The charged hadron spectra in p+Pb and pp collisions at $\\sqrt{s}=5.02$TeV are measured with the ATLAS experiment at the LHC. The measurements are performed with p+Pb data recorded in 2013 with an integrated luminosity of 25nb${}^{-1}$ and pp data recorded in 2015 with an integrated luminosity of 28pb${}^{-1}$. The p+Pb results are directly compared to pp spectra, as a ratio scaled by the number of binary nucleon-nucleon collisions, the nuclear modification factor $R_\\mathrm{pPb}$. The study of $R_\\mathrm{pPb}$ allows a detailed comparison of the collision systems in different centrality intervals and up to high transverse momentum. It is shown that the nuclear modification factor does not have any significant deviation from unity in the high transverse momentum region.
The Emergence of Hadrons from QCD Color
Brooks, William; Color Dynamics in Cold Matter (CDCM) Collaboration
2015-10-01
The formation of hadrons from energetic quarks, the dynamical enforcement of QCD confinement, is not well understood at a fundamental level. In Deep Inelastic Scattering, modifications of the distributions of identified hadrons emerging from nuclei of different sizes reveal a rich variety of spatial and temporal characteristics of the hadronization process, including its dependence on spin, flavor, energy, and hadron mass and structure. The EIC will feature a wide range of kinematics, allowing a complete investigation of medium-induced gluon bremsstrahlung by the propagating quarks, leading to partonic energy loss. This fundamental process, which is also at the heart of jet quenching in heavy ion collisions, can be studied for light and heavy quarks at the EIC through observables quantifying hadron ``attenuation'' for a variety of hadron species. Transverse momentum broadening of hadrons, which is sensitive to the nuclear gluonic field, will also be accessible, and can be used to test our understanding from pQCD of how this quantity evolves with pathlength, as well as its connection to partonic energy loss. The evolution of the forming hadrons in the medium will shed new light on the dynamical origins of the forces between hadrons, and thus ultimately on the nuclear force. Supported by the Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) of Chile.
PREFACE: Focus section on Hadronic Physics
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
Gluonic excitations in hadronic spectroscopy
Close, F.E.
1983-09-01
Theoretical expectations are described for new forms of hadronic matter containing gluons as excitable degrees of freedom. Particular attention is paid to hybrid states containing both quarks and gluons. Recent work on the spectroscopy of hybrid mesons and hybrid baryons is reviewed. Comparisons of bag model, lattice QCD and QCD sum rule predictions are made and some confrontation with data attempted. (author)
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.
QCD in hadron-hadron collisions
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
High energy hadron-hadron collisions
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
The COMPASS Hadron Spectroscopy Programme
Austregesilo, A
2011-01-01
COMPASS is a fixed-target experiment at the CERN SPS for the investigation of the structure and the dynamics of hadrons. The experimental setup features a large acceptance and high momentum resolution spectrometer including particle identification and calorimetry and is therefore ideal to access a broad range of different final states. Following the promising observation of a spin-exotic resonance during an earlier pilot run, COMPASS focused on light-quark hadron spectroscopy during the years 2008 and 2009. A data set, world leading in terms of statistics and resolution, has been collected with a 190GeV/c hadron beam impinging on either liquid hydrogen or nuclear targets. Spin-exotic meson and glueball candidates formed in both diffractive dissociation and central production are presently studied. Since the beam composition includes protons, the excited baryon spectrum is also accessible. Furthermore, Primakoff reactions have the potential to determine radiative widths of the resonances and to probe chiral pe...
Pion form factor in QCD at intermediate momentum transfers
Braun, V. M.; Khodjamirian, A.; Maul, M.
2000-04-01
We present a quantitative analysis of the electromagnetic pion form factor in the light-cone sum rule approach, including radiative corrections and higher-twist effects. The comparison to the existing data favors the asymptotic profile of the pion distribution amplitude and allows us to estimate the deviation: [∫du/uφπ(u)]/[∫du/uφasπ(u)]=1.1+/-0.1 at the scale of 1 GeV. Special attention is paid to the precise definition and interplay of soft and hard contributions at intermediate momentum transfer, and to the matching of the sum rule to the perturbative QCD prediction. We observe a strong numerical cancellation between the soft (end-point) contribution and power-suppressed hard contributions of higher twist, so that the total nonperturbative correction to the usual PQCD result turns out to be of the order of 30% for Q2~1 GeV2.
Five-meson VDM fits to the nucleon form factors
Mehrotra, S.; Roos, M.
1975-01-01
Nucleon electromagnetic form factor data in the spacelike and the timelike regions are fitted with a VDM sum of (up to five) isovector and isoscalar pole terms. Finite width effects are included in the rho and the rhosup(,) terms. The effects of including the rhosup(,) and the psi(3105) are studied. Good fits are found only when the rhosup(,) is allowed to have a too low mass (1.2-1.4 GeV) and when in addition some of the couplings or other derived quantities disagree with other estimates. It is concluded that VDM is unable to describe the data unless one introduces a number of yet unknown mesons, such as ωsup(,), phisup(,), rhosup(,)(1.2), etc. (author)
Form factors and related quantities in clothed-particle representation
Shebeko Alexander
2017-01-01
Full Text Available We show new applications of the notion of clothed particles in quantum field theory. Its realization by means of the clothing procedure put forward by Greenberg and Schweber allows one to express the total Hamiltonian H and other generators of the Poincaré group for a given system of interacting fields through the creation (annihilation operators for the so-called clothed particles with physical (observed properties. Here such a clothed particle representation is used to calculate the matrix elements (shortly, form factors of the corresponding Nöther current operators sandwiched between the H eigenstates. Our calculations are performed with help of an iterative technique suggested by us earlier when constructing the NN → πNN transition operators. As an illustration, we outline some application of our approach in the spinor quantum electrodynamics.
Finite-lattice form factors in free-fermion models
Iorgov, N; Lisovyy, O
2011-01-01
We consider the general Z 2 -symmetric free-fermion model on the finite periodic lattice, which includes as special cases the Ising model on the square and triangular lattices and the Z n -symmetric BBS τ (2) -model with n = 2. Translating Kaufman's fermionic approach to diagonalization of Ising-like transfer matrices into the language of Grassmann integrals, we determine the transfer matrix eigenvectors and observe that they coincide with the eigenvectors of a square lattice Ising transfer matrix. This allows us to find exact finite-lattice form factors of spin operators for the statistical model and the associated finite-length quantum chains, of which the most general is equivalent to the XY chain in a transverse field
Electric form factor of the proton through recoil polarization
Punjabi, V.
2000-01-01
The electromagnetic form factors of the nucleon, G E and G M , describe the charge and current distribution inside the nucleon and thus are quite intimately related to its structure. Jefferson Lab experiment 93-027 measured P l and Pt, the longitudinal and transverse recoil proton polarization, respectively, for the 1 H(e-vector,e'p-vector) reaction in the four-momentum transfer squared range of 0.5 to 3.5 GeV 2 , using the Hall A facility with two high resolution spectrometers and a Focal Plane Polarimeter. The ratio G Ep /G Mp is directly proportional to the ratio P t /P l . These data have unprecedented precision, and show for the first time that the Q 2 dependence of G Ep and G Mp is very different. (author)
Conformal anomaly of generalized form factors and finite loop integrals
Chicherin, Dmitry
2017-01-01
We reveal a new mechanism of conformal symmetry breaking at Born level. It occurs in generalized form factors with several local operators and an on-shell state of massless particles. The effect is due to hidden singularities on collinear configurations of the momenta. This conformal anomaly is different from the holomorphic anomaly of amplitudes. We present a number of examples in four and six dimensions. We find an application of the new conformal anomaly to finite loop momentum integrals with one or more massless legs. The collinear region around a massless leg creates a contact anomaly, made visible by the loop integration. The anomalous conformal Ward identity for an $\\ell-$loop integral is a 2nd-order differential equation whose right-hand side is an $(\\ell-1)-$loop integral. We show several examples, in particular the four-dimensional scalar double box.
Current correlators and form factors in the resonance region
Rosell, I. [Departamento de Ciencias Fisicas, Matematicas y de la Computacion, Universidad CEU Cardenal Herrera, c/Sant Bartomeu 55, E-46115 Alfara del Patriarca, Valencia (Spain); IFIC, Universitat de Valencia - CSIC, Apt. Correus 22085, E-46071 Valencia (Spain)
2009-01-15
Within Resonance Chiral Theory and in the context of QCD current correlators at next-to-leading order in 1/N{sub C}, we have analyzed the two-body form factors which include resonances as a final state. The short-distance constraints have been studied. One of the main motivations is the estimation of the chiral low-energy constants at subleading order, that is, keeping full control of the renormalization scale dependence. As an application we show the resonance estimation of some coupling, L{sub 10}{sup r}({mu}{sub 0})=(-4.4{+-}0.9).10{sup -3} and C{sub 87}{sup r}({mu}{sub 0})=(3.1{+-}1.1).10{sup -5}.
Disconnected-Sea Quarks Contribution to Nucleon Electromagnetic Form Factors
Sufian, Raza Sabbir
We present comprehensive analysis of the light and strange disconnected-sea quarks contribution to the nucleon electric and magnetic form factors. The lattice QCD estimates of strange quark magnetic moment GsM (0) = -0.064(14)(09) microN and the mean squared charge radius E = -0.0043(16)(14) fm2 are more precise than any existing experimental measurements and other lattice calculations. The lattice QCD calculation includes ensembles across several lattice volumes and lattice spacings with one of the ensembles at the physical pion mass. We have performed a simultaneous chiral, infinite volume, and continuum extrapolation in a global fit to calculate results in the continuum limit. We find that the combined light-sea and strange quarks contribution to the nucleon magnetic moment is -0.022(11)(09) microN and to the nucleon mean square charge radius is -0.019(05)(05) fm 2. The most important outcome of this lattice QCD calculation is that while the combined light-sea and strange quarks contribution to the nucleon magnetic moment is small at about 1%, a negative 2.5(9)% contribution to the proton charge radius and a relatively larger positive 16.3(6.1)% contribution to the neutron charge radius come from the sea quarks in the nucleon. For the first time, by performing global fits, we also give predictions of the light-sea and strange quarks contributions to the nucleon electric and magnetic form factors at the physical point and in the continuum and infinite volume limits in the momentum transfer range of 0 ≤ Q2 ≤ 0.5 GeV2.
CMS Central Hadron Calorimeter
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.
Problems of hadron electrodynamics
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
Balek, Petr; The ATLAS collaboration
2016-01-01
The charged hadron spectra in p+Pb and pp collisions at $\\sqrt{s}=5.02$TeV are measured with the ATLAS experiment at the LHC. The measurements are performed with p+Pb data recorded in 2013 with an integrated luminosity of 25nb${}^{-1}$ and pp data recorded in 2015 with an integrated luminosity of 25pb${}^{-1}$. The p+Pb results are directly compared to pp spectra, as a ratio scaled by the number of binary nucleon-nucleon collisions, the nuclear modification factor $R\\mathrm{pPb}$. It allows for a detailed comparison of the collision systems in different centrality intervals and up to high transverse momentum.
Cahill, R.T.
1992-01-01
A review is given of progress in deriving the effective action for hadronic physics, S[π, ρ, ω, .., anti N, N, ..], from the fundamental defining action of QCD, S[anti q, q, A μ a ]. This is a problem in quantum field theory and the most success so far has been achieved using functional integral calculus (FIC) techniques. This formulates the problem as an exercise in changing the variables of integration in the functional integrals, from those of the quark and gluon fields to those of the (bare) meson and baryon fields. The appropriate variables are determined by the dynamics of QCD, and the final hadronic variables (essentially the 'normal modes' of QCD) are local fields describing the 'centre-of-mass' motion of extended bound states of quarks. The quarks are extensively dressed by the gluons, and the detailed aspects of the hidden chiral symmetry emerge naturally from the formalism. Particular attention is given to covariant integral equations which determine bare nucleon structure (i.e. in the quenched approximation). These equations, which arise from the closed double-helix diagrams of the FIC analysis, describe the baryons in terms of quark-diquark structure, in the form of Faddeev equations. This hadronisation of QCD also generates the dressing of these baryons by the pions, and the non-local πNN coupling. (orig.)
IEEE 1588 Time Synchronization Board in MTCA.4 Form Factor
Jabłoński, G.; Makowski, D.; Mielczarek, A.; Orlikowski, M.; Perek, P.; Napieralski, A.; Makijarvi, P.; Simrock, S.
2015-06-01
Distributed data acquisition and control systems in large-scale scientific experiments, like e.g. ITER, require time synchronization with nanosecond precision. A protocol commonly used for that purpose is the Precise Timing Protocol (PTP), also known as IEEE 1588 standard. It uses the standard Ethernet signalling and protocols and allows obtaining timing accuracy of the order of tens of nanoseconds. The MTCA.4 is gradually becoming the platform of choice for building such systems. Currently there is no commercially available implementation of the PTP receiver on that platform. In this paper, we present a module in the MTCA.4 form factor supporting this standard. The module may be used as a timing receiver providing reference clocks in an MTCA.4 chassis, generating a Pulse Per Second (PPS) signal and allowing generation of triggers and timestamping of events on 8 configurable backplane lines and two front panel connectors. The module is based on the Xilinx Spartan 6 FPGA and thermally stabilized Voltage Controlled Oscillator controlled by the digital-to-analog converter. The board supports standalone operation, without the support from the host operating system, as the entire control algorithm is run on a Microblaze CPU implemented in the FPGA. The software support for the card includes the low-level API in the form of Linux driver, user-mode library, high-level API: ITER Nominal Device Support and EPICS IOC. The device has been tested in the ITER timing distribution network (TCN) with three cascaded PTP-enabled Hirschmann switches and a GPS reference clock source. An RMS synchronization accuracy, measured by direct comparison of the PPS signals, better than 20 ns has been obtained.
Factorization of heavy-to-light form factors in soft-collinear effective theory
Beneke, Martin; Feldmann, Th.
2004-01-01
Heavy-to-light transition form factors at large recoil energy of the light meson have been conjectured to obey a factorization formula, where the set of form factors is reduced to a smaller number of universal form factors up to hard-scattering corrections. In this paper we extend our previous investigation of heavy-to-light currents in soft-collinear effective theory to final states with invariant mass Lambda^2 as is appropriate to exclusive B meson decays. The effective theory contains soft modes and two collinear modes with virtualities of order m_b*Lambda (`hard-collinear') and Lambda^2. Integrating out the hard-collinear modes results in the hard spectator-scattering contributions to exclusive B decays. We discuss the representation of heavy-to-light currents in the effective theory after integrating out the hard-collinear scale, and show that the previously conjectured factorization formula is valid to all orders in perturbation theory. The naive factorization of matrix elements in the effective theory ...
Nucleon form factors and hidden symmetry in holographic QCD
Hong, D.K.; Rho, M.; Yee, H.-U.; Yi, P.
2007-10-01
The vector dominance of the electromagnetic (EM) form factors both for mesons and baryons arises naturally in holographic QCD, where both the number of colors and the 't Hooft coupling are taken to be very large, offering a bona-fide derivation of the notion of vector dominance. The crucial ingredient for this is the infinite tower of vector mesons in the approximations made which share features that are characteristic of the quenched approximation in lattice QCD. We approximate the infinite sum by contributions from the lowest four vector mesons of the tower which turn out to saturate the charge and magnetic moment sum rules within a few % and compute them totally free of unknown parameters for momentum transfers Q 2 approx.= 1 GeV 2 . We identify certain observables that can be reliably computed within the approximations and others that are not, and discuss how the improvement of the latter can enable one to bring holographic QCD closer to QCD proper. (author)
Conformal anomaly of generalized form factors and finite loop integrals
Chicherin, Dmitry; Sokatchev, Emery
2018-04-01
We reveal a new mechanism of conformal symmetry breaking at Born level. It occurs in generalized form factors with several local operators and an on-shell state of massless particles. The effect is due to hidden singularities on collinear configurations of the momenta. This conformal anomaly is different from the holomorphic anomaly of amplitudes. We present a number of examples in four and six dimensions. We find an application of the new conformal anomaly to finite loop momentum integrals with one or more massless legs. The collinear region around a massless leg creates a contact anomaly, made visible by the loop integration. The anomalous conformal Ward identity for an ℓ-loop integral is a 2nd-order differential equation whose right-hand side is an (ℓ - 1)-loop integral. It could serve as a new useful tool to find/test analytic expressions for conformal integrals. We illustrate this point with several examples of known integrals. We propose a new differential equation for the four-dimensional scalar double box.
Measurements of the nucleon form factors at large momentum transfers
Andivahis, L.; Bosted, P.; Lung, A.; Arnold, R.; Keppel, C.; Rock, S.; Spengos, M.; Szalata, Z.; Tao, L.; Stuart, L.; Dietrich, F.; Alster, J.; Lichtenstadt, J.; Chang, C.; Dodge, W.; Gearhart, R.; Kuhn, S.; Gomez, J.; Griffioen, K.; Hicks, R.; Miskimen, R.; Peterson, G.; Rokni, S.; Hyde-Wright, C.; Swartz, K.; Petratos, G.; Sakumoto, W.
1992-12-01
New measurements of the electric G E (Q 2 ) and magnetic G M (Q 2 ) form factors of the nucleons are reported. The proton data cover the Q 2 range from 1.75 to 8.83 (GeV/c) 2 and the neutron data from 1.75 to 4.00 (GeV/c) 2 , more than doubling the range of previous data. Scaled by the dipole fit, G D (Q 2 ), the results for G Mp (Q 2 )/μ p G D (Q 2 ) decrease smoothly from 1.05 to 0.92, while G Ep (Q 2 )/G D (Q 2 ) is consistent with unity. The preliminary results for Gm.(Q2)1 GD(Q2) consistent with unity, while F En 2 is consistent with zero at all values of Q 2 . Comparisons are made to QCD Sum Rule, diquark, constituent quark, and VMD models, none of which agree with all of the new data
Calculation of hadronic transition amplitudes in charm physics
Klein, Christoph
2011-01-01
Transitions of charmed hadrons are of significant importance, since they provide possibilities to extract the CKM matrix elements V cd and V cs from experimental data as well as interesting channels to search for new physics effects. However, quarks are bound in hadrons, and it is necessary to describe this effect in a reliable way, to study the underlying flavour dynamics. For this, one has to use nonperturbative tools, to determine the corresponding transition amplitudes. The results of such calculations can furthermore be of use, to test the predictions of QCD and to contribute to a deeper understanding of the structure of hadrons. In this thesis two topics are investigated using the method of QCD light-cone sum rules (LCSRs). The first topic consists in the form factors of the semileptonic decays D → πlν l and D → Klν l , for which new results are calculated using up-to-date input values. Since LCSRs are not applicable in the whole range of kinematics, they are extrapolated by the use of appropriate parametrisations and the results agree well with experimental data. The second topic are the transitions of charmed baryons to a nucleon. Here the corresponding transition form factors and in addition the hadronic Λ c D (*) N and Σ c D (*) N coupling constants are calculated - the latter by the consideration of double dispersion relations. These coupling constants are of special interest for the description of hadronic interactions, like open charm production in proton-antiprotoncollisions. Furthermore there appears the problem, that both parity states of a baryon contribute to the considered functional representation, for which a consistent way to separate them is presented. (orig.)
Baryon form factors at high momentum transfer and generalized parton distributions
Stoler, Paul
2002-01-01
Nucleon form factors at high momentum transfer t are treated in the framework of generalized parton distributions (GPD's). The possibility of obtaining information about parton high transverse momentum components by application of GPD's to form factors is discussed. This is illustrated by applying an ad hoc 2-body parton wave function to elastic nucleon form factors F 1 and F 2 , the N→Δ transition magnetic form factor G M * , and the wide angle Compton scattering form factor R 1
Hadron--hadron reactions, high multiplicity
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
Supersymmetry across the Hadronic Spectrum
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.
Exclusive hadronic processes and color transparency
It is known that at asymptotically large momentum transfer certain exclusive hadronic ... indicates that the Brodsky–Lepage factorization scheme fails, independent of ..... A basic feature of *-initiated reactions is that most events are knocked out.
Nucleon Structure and Hyperon Form Factors from Lattice QCD.
Lin,H.W.
2007-06-11
In this work, I report the latest lattice QCD calculations of nucleon and hyperon structure from chiral fermions in 2+1-flavor dynamical simulations. All calculations are done with a chirally symmetric fermion action, domain-wall fermions, for valence quarks. I begin with the latest lattice results on the nucleon structure, focusing on results from RBC/UKQCD using 2+1-flavor chiral fermion actions. We find the chiral-extrapolated axial coupling constant at physical pion mass point. to be 1.23(5), consistent with experimental value. The renormalization constants for the structure functions are obtained from RI/MOM-scheme non-perturbative renormalization. We find first moments of the polarized and unpolarized nucleon structure functions at zero transfer momentum to be 0.133(13) and 0.203(23) respectively, using continuum chiral extrapolation. These are consistent with the experimental values, unlike previous calculations which have been 50% larger. We also have a prediction for the transversity, which we find to be 0.56(4). The twist-3 matrix element is consistent with zero which agrees with the prediction of the Wandzura-Wilczek relation. In the second half of this work, I report an indirect dynamical estimation of the strangeness proton magnetic moments using mixed actions. With the analysis of hyperon form factors and using charge symmetry, the strangeness of proton is found to be -0.066(2G), consistent with the Adelaide-JLab Collaboration's result. The hyperon {Sigma} and {Xi} axial coupling constants are also performed for the first time in a lattice calculation, g{sub {Sigma}{Sigma}} = 0.441(14) and g{sub {Xi}{Xi}} = -0.277(11).
Nucleon Structure and hyperon form factors from lattice QCD
Lin, Huey-Wen
2007-06-11
In this work, I report the latest lattice QCD calculations of nucleon and hyperon structure from chiral fermions in 2+1-flavor dynamical simulations. All calculations are done with a chirally symmetric fermion action, domain-wall fermions, for valence quarks. I begin with the latest lattice results on the nucleon structure, focusing on results from RBC/UKQCD using 2+1-flavor chiral fermion actions. We find the chiral-extrapolated axial coupling constant at physical pion mass point to be 1.23(5), consistant with experimental value. The renormalization constants for the structure functions are obtained from RI/MOM-scheme non-perturbative renormalization. We find first moments of the polarized and unpolarized nucleon structure functions at zero transfer momentum to be 0.133(13) and 0.203(23) respectively, using continuum chiral extrapolation. These are consistent with the experimental values, unlike previous calculations which have been 50% larger. We also have a prediction for the transversity, which we find to be 0.56(4). The twist-3 matrix element is consistent with zero which agrees with the prediction of the Wandzura-Wilczek relation. In the second half of this work, I report an indirect dynamical estimation of the strangeness proton magnetic moments using mixed actions. With the analysis of hyperon form factors and using charge symmetry, the strangeness of proton is found to be -0.066(26), consistent with the Adelaide-JLab Collaboration's result. The hyperon Sigma and Xi axial coupling constants are also performed for the first time in a lattice calculation, g_SigmaSigma = 0.441(14) and g_XiXi = -0.277(11).
Igi, K.
1979-01-01
This paper is related to mini-rapporteur talk on baryonium spectroscopy. First of all, the models of baryonium, namely the diquark model, the string picture, the linear baryonium and the bag model, are described. All of these models so far discussed are highly suggestive. In this paper, discussions are confined to the spectroscopy of the string and the bag models. Because of the color degree of freedom, the bag model has mock diquonium and mock mesonium besides true baryonium. It might be possible that the string model takes into account only a part of them. The constraints among baryonium, baryon and boson trajectories using duality and unitarity were proposed as a guide for classifying various spectra. Inequalities were derived as the modest and reliable constraints on baryonium intercepts from baryon and boson intercepts by imposing unitarity and Regge behaviors on scattering amplitudes. As a consequence of residue factorization and duality, the baryonium slopes were derived. The spin of S (1936) was also obtained. The baryonium containing s or c quarks can also be studied. Topics such as the EXD patterns of baryons, linear baryons, linear Regge trajectories for all Q-anti Q families, and the Al and two Q mesons, are presented in this paper. Comments on di-baryon are described. (Kato, T.)
PREFACE: Focus section on Hadronic Physics Focus section on Hadronic Physics
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
Cytokinin response factors regulate PIN-FORMED auxin transporters
Šimášková, M.; O'Brien, J.A.; Khan, M.; Van Noorden, G.; Ötvös, K.; Vieten, A.; De Clercq, E.; Van Haperen, J.M.A.; Cuesta, C.; Hoyerová, Klára; Vanneste, S.; Marhavý, P.; Wabnik, K.; Van Breusegem, F.; Nowack, M.; Murphy, A.; Friml, J.; Weijers, D.; Beeckman, T.; Benková, E.
2015-01-01
Roč. 6, NOV (2015), s. 8717 ISSN 2041-1723 Institutional support: RVO:61389030 Keywords : ARABIDOPSIS -THALIANA * ROOT-MERISTEM * TRANSCRIPTION FACTORS Subject RIV: ED - Physiology Impact factor: 11.329, year: 2015
Conservative flight with a varying load factor and closed form ...
Conservative flight performance of an aircraft with constant load factor was analysed by ... Within the frame work of flat earth hypotheses the equations of motion of an aircraft as obtained by ..... load factor function if this inequality holds good.
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)
Hadron correlations from recombination
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.
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.
Density oscillations within hadrons
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
Structure of hadrons. Proceedings
Feldmeier, H.; Knoll, J.; Noerenberg, W.; Wambach, J.
2001-01-01
The following topics were dealt with: Hadronic reactions and resonances, structure of mesons, baryons, glueballs, and hybrids, physics with strange and charmed quarks, future projects and facilities. (HSI)
Hadronic couplings of open beauty states
Ram, S.N.; Singh, C.P.
1982-08-01
Strong interaction coupling parameters of particles with beauty quantum number are obtained using dispersion sum rules in various forms, e.g. current algebra sum rules, superconvergence sum rules and finite energy sum rules etc. These sum rules lead to a set of algebraic relations among masses and coupling constants. We compare the hadronic couplings of beautiful particles as obtained from various techniques and discuss their implications on the hadronic production of these states. (author)
Exclusive hadronic and nuclear processes in QCD
Brodsky, S.J.
1985-12-01
Hadronic and nuclear processes are covered, in which all final particles are measured at large invariant masses compared with each other, i.e., large momentum transfer exclusive reactions. Hadronic wave functions in QCD and QCD sum rule constraints on hadron wave functions are discussed. The question of the range of applicability of the factorization formula and perturbation theory for exclusive processes is considered. Some consequences of quark and gluon degrees of freedom in nuclei are discussed which are outside the usual domain of traditional nuclear physics. 44 refs., 7 figs
Forms and factors of peer violence and victimisation
Dinić Bojana; Sokolovska Valentina; Milovanović Ilija; Oljača Milan
2014-01-01
The main aim of this study was to explore the latent structure of violence and victimisation based on the factor analysis of the Peer Violence and Victimisation Questionnaire (PVVQ), as well as to examine the correlates of violence and victimisation. The sample included 649 secondary school students (61.8% male) from the urban area. Besides the PVVQ, the Aggressiveness questionnaire AVDH was administered. Based on parallel analysis, three factors were extra...
Matter density distributions and elastic form factors of some two ...
Ahmed N Abdullah
2017-08-31
Aug 31, 2017 ... include the proton, neutron and matter density distributions, the corresponding rms radii, the binding energy per nucleon and the charge form ... the nuclear structure models based on the experimental data for stable nuclei ... Most exotic nuclei are so short lived that they cannot be used as targets at rest.
Two neutron transfer form factor for the reaction 42Ca(p,t)40Ca
Meyer, R.H.
1978-01-01
In an attempt to better interpret experimental data concerning the two-neutron pickup process 42 Ca(p,t) 40 Ca, a detailed study of the form factors associated with the reaction is carried out. A set of coupled integro-differential equations describing these form factors is derived, starting from a microscopic, model-independent Hamiltonian. These equations allow contributions to the form factors from hole terms as well as from the particle and so-called ''continuum'' states, which were previously studied. An approximate solution of the form factor equations is obtained by neglecting the coupling terms and expressing the form factor in terms of a set of Sturmian states. Form factors for the transition to the 40 Ca ground state (O 1 + ) are calculated using various sets of Sturmian states. The inclusion of hole states is found to have a major effect upon both the shape of the form factor and the size of the related cross section. Finally, a comparison is made between the O 1 + form factors calculated using Sturmian states and a O 1 + form factor obtained using Sturmian states and a O 1 + form factor obtained using the coexistence model. It is found that a form factor based on Sturmian particle and hole states is very similar to the form factor obtained from the coexistence model calculation
New high statistics measurement of Ke4 decay form factors and ππ scattering phase shifts TH1"-->
Batley, J. R.; Culling, A. J.; Kalmus, G.; Lazzeroni, C.; Munday, D. J.; Slater, M. W.; Wotton, S. A.; Arcidiacono, R.; Bocquet, G.; Cabibbo, N.; Ceccucci, A.; Cundy, D.; Falaleev, V.; Fidecaro, M.; Gatignon, L.; Gonidec, A.; Kubischta, W.; Norton, A.; Maier, A.; Patel, M.; Peters, A.; Balev, S.; Frabetti, P. L.; Goudzovski, E.; Hristov, P.; Kekelidze, V.; Kozhuharov, V.; Litov, L.; Madigozhin, D.; Marinova, E.; Molokanova, N.; Polenkevich, I.; Potrebenikov, Y.; Stoynev, S.; Zinchenko, A.; Monnier, E.; Swallow, E.; Winston, R.; Rubin, P.; Walker, A.; Baldini, W.; Cotta Ramusino, A.; Dalpiaz, P.; Damiani, C.; Fiorini, M.; Gianoli, A.; Martini, M.; Petrucci, F.; Savrié, M.; Scarpa, M.; Wahl, H.; Bizzeti, A.; Calvetti, M.; Celeghini, E.; Iacopini, E.; Lenti, M.; Martelli, F.; Ruggiero, G.; Veltri, M.; Behler, M.; Eppard, K.; Kleinknecht, K.; Marouelli, P.; Masetti, L.; Moosbrugger, U.; Morales Morales, C.; Renk, B.; Wache, M.; Wanke, R.; Winhart, A.; Coward, D.; Dabrowski, A.; Fonseca Martin, T.; Shieh, M.; Szleper, M.; Velasco, M.; Wood, M. D.; Anzivino, G.; Cenci, P.; Imbergamo, E.; Nappi, A.; Pepe, M.; Petrucci, M. C.; Piccini, M.; Raggi, M.; Valdata-Nappi, M.; Cerri, C.; Collazuol, G.; Costantini, F.; Dilella, L.; Doble, N.; Fantechi, R.; Fiorini, L.; Giudici, S.; Lamanna, G.; Mannelli, I.; Michetti, A.; Pierazzini, G.; Sozzi, M.; Bloch-Devaux, B.; Cheshkov, C.; Chèze, J. B.; de Beer, M.; Derré, J.; Marel, G.; Mazzucato, E.; Peyaud, B.; Vallage, B.; Holder, M.; Ziolkowski, M.; Bifani, S.; Biino, C.; Cartiglia, N.; Clemencic, M.; Goy Lopez, S.; Marchetto, F.; Dibon, H.; Jeitler, M.; Markytan, M.; Mikulec, I.; Neuhofer, G.; Widhalm, L.
2008-04-01
We report results from a new measurement of the Ke4 decay K±→π+π-e±ν by the NA48/2 collaboration at the CERN SPS, based on a partial sample of more than 670 000 Ke4 decays in both charged modes collected in 2003. The form factors of the hadronic current (F,G,H) and ππ phase difference (δ=δs-δp) have been measured in ten independent bins of the ππ mass spectrum to investigate their variation. A sizeable acceptance at large ππ mass, a low background and a very good resolution contribute to an improved experimental accuracy, a factor two better than in the previous measurement, when extracting the ππ scattering lengths a0 0 and a0 2. Under the assumption of isospin symmetry and using numerical solutions of the Roy equations, the following values are obtained in the plane (a0 0,a0 2): a0 0=0.233±0.016stat±0.007syst,a0 2=-0.0471±0.011stat±0.004syst. The presence of potentially large isospin effects is also considered and will allow comparison with precise predictions from Chiral Perturbation Theory.
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
Ernst, David J.
1992-01-01
At a Workshop on the Future of Hadron Facilities, held on 15-16 August at Los Alamos National Laboratory, several speakers pointed out that the US physics community carrying out fixed target experiments with hadron beam had not been as successful with funding as it deserved. To rectify this, they said, the community should be better organized and present a more united front
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
Statistical Hadronization and Holography
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...
Perspectives in hadron spectroscopy
Richard, J.M. [Universite Joseph Fourier-IN2P3-CNRS, Lab. de Physique Subatomique et Cosmologie, 38 - Grenoble (France)
2005-07-01
A brief survey is presented of selected recent results on hadron spectroscopy and related theoretical studies. Among the new hadron states, some of them are good candidates for exotic structures: chiral partners of ground-states, hybrid mesons (quark, antiquark and constituent gluon), four-quark states, or meson-meson molecules.
Ernst, David J.
1992-11-15
At a Workshop on the Future of Hadron Facilities, held on 15-16 August at Los Alamos National Laboratory, several speakers pointed out that the US physics community carrying out fixed target experiments with hadron beam had not been as successful with funding as it deserved. To rectify this, they said, the community should be better organized and present a more united front.
Firetube model and hadron-hadron collisions
Nazareth, R.A.M.S.; Kodama, T.; Portes Junior, D.A.
1992-01-01
A new version of the fire tube model is developed to describe hadron-hadron collisions at ultrarelativistic energies. Several improvements are introduced in order to include the longitudinal expansion of intermediate fireballs, which remedies the overestimates of the transverse momenta in the previous version. It is found that, within a wide range of incident energies, the model describes well the experimental data for the single particle rapidity distribution, two-body correlations in the pseudo-rapidity, transverse momentum spectra of pions and kaons, the leading particle spectra and the K/π ratio. (author)
M. Modarres
2017-09-01
Full Text Available Quite recently, two sets of new experimental data from the LHCb and the CMS Collaborations have been published, concerning the production of the Z0 vector boson in hadron–hadron collisions with the center-of-mass energy ECM=s=13TeV. On the other hand, in our recent work, we have conducted a set of semi-NLO calculations for the production of the electro-weak gauge vector bosons, utilizing the unintegrated parton distribution functions (UPDF in the frameworks of Kimber–Martin–Ryskin (KMR or Martin–Ryskin–Watt (MRW and the kt-factorization formalism, concluding that the results of the KMR scheme are arguably better in describing the existing experimental data, coming from D0, CDF, CMS and ATLAS Collaborations. In the present work, we intend to follow the same semi-NLO formalism and calculate the rate of the production of the Z0 vector boson, utilizing the UPDF of KMR within the dynamics of the recent data. It will be shown that our results are in good agreement with the new measurements of the LHCb and the CMS Collaborations.
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
Precision kaon and hadron physics with KLOE
Bossi, F.; De Lucia, E.; Lee-Franzini, J.; Miscetti, S.; Palutan, M.
2008-01-01
We describe the KLOE detector at DAΦNE, the Frascati φ, and its physics program. We begin with a brief description of the detector design and operation. Kaon physics is a major topic of investigation with KLOE thanks in part to the unique availability of pure K S , K L , K ± beams at a φ. We have measured all significant branching ratios of all kaon species, the K L and K ± lifetimes and the K → π form factor's t dependence. From the measurements we verify the validity of Cabibbo unitarity and lepton universality. We have studied properties of light scalar and pseudoscalar mesons with unprecedented accuracy. We have measured the e + e - → π + π - cross-section necessary for computing the major part of the hadronic contribution to the muon anomaly. The methods employed in all the above measurements as well as the φ leptonic width, precision mass measurements and searches for forbidden or extremely rare decays of kaons and η-mesons arc described. The impact of our results on flavor and hadron physics to date, as well as an outlook for further improvement in the near future, are discussed
Recruitment of bloom-forming cyanobacteria and its driving factors ...
Based on most of the literature, this paper reviewed the progress made in following aspects: cognition to cyanobacteria recruitment, various traps for studying cyanobacteria recruitment in lakes, recruitment patterns of some species of cyanobacteria, and the driving factors for recruitment. Additionally, perspective studies of ...
High energy hadron spin-flip amplitude
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
Golovanova, N.F.; Ibraeva, E.T.; Neudatchin, V.G.
1978-01-01
Different multiplicities and their interference in hadron scattering have been investigated on the basis of a new dynamic approach to quasi-elastic knock-out of nucleon clusters by fast hadrons from light nuclei. It is shown that in the region of momentum transfer values p, where scattering multiplicities less than b are predominant, the effective numbers and form factors determined in Refs. 1) -- 3) no longer act as pure structural nuclear factors (b means the number of nucleons in the knocked-out cluster). These characteristics are significantly dependent on the process dynamics. Only in the region of values p, where the maximum hadron scattering multiplicity b is realized, the effective numbers and form factors do assume the purely structural meaning. (auth.)
Hadron therapy information sharing prototype
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.
Sum rules for quasifree scattering of hadrons
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.
High resolution hadron calorimetry
Wigmans, R.
1987-01-01
The components that contribute to the signal of a hadron calorimeter and the factors that affect its performance are discussed, concentrating on two aspects; energy resolution and signal linearity. Both are decisively dependent on the relative response to the electromagnetic and the non-electromagnetic shower components, the e/h signal ratio, which should be equal to 1.0 for optimal performance. The factors that determine the value of this ratio are examined. The calorimeter performance is crucially determined by its response to the abundantly present soft neutrons in the shower. The presence of a considerable fraction of hydrogen atoms in the active medium is essential for achieving the best possible results. Firstly, this allows one to tune e/h to the desired value by choosing the appropriate sampling fraction. And secondly, the efficient neutron detection via recoil protons in the readout medium itself reduces considerably the effect of fluctuations in binding energy losses at the nuclear level, which dominate the intrinsic energy resolution. Signal equalization, or compensation (e/h = 1.0) does not seem to be a property unique to 238 U, but can also be achieved with lead and probably even iron absorbers. 21 refs.; 19 figs
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
Hadron accelerators in medicine
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)
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.
Study of the p(e,e'π+)n electro-production reaction: form factor and electromagnetic radius of pion
Michel, Bernard
1977-01-01
After having recalled the definitions and theoretical knowledge on the form factor and electromagnetic radius of hadron and pion, and discussed the relationship between electro-production and form factor for the pion, this research thesis recalls some theoretical aspects of the electro-production process. The author discusses the reaction kinematics and shows how the electro-production cross section can be broken down in terms of photon polarization. Then, he focuses on the cross section dynamic structure. After having recalled the different possible choices for amplitudes, he studies their behaviour, firstly within the framework of the Born approximation, and then within the framework of commonly used models, notably to take the resonant part of the phenomenon into account. The limits of the different models are outlined. The second part addresses the study of forward electro-production. The author shows how the pion form factor can be simply optimized. The author describes the experimental arrangement: electron beam and liquid hydrogen target, detection system, normalisation device, data acquisition logics. In the next chapter, the author describes how data are recorded until the obtainment of N electro-production events. Results are then interpreted in terms of form factor and electromagnetic radius. They are also compared with published results obtained with other electro-production experiments or measurements based on other processes [fr
Analyticity in a phenomenology of electro-weak structure of hadrons
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)
Srivastava, D K
2001-01-01
The production of single photons in Pb+Pb collisions at the CERN SPS as measured by the WA98 experiment is analysed. A quark gluon plasma is assumed to be formed initially, which expands, cools, hadronizes, and undergoes freeze-out. A rich hadronic equation of state is used and the transverse expansion of the interacting system is taken into account. The recent estimates of photon production in quark-matter (at two loop level) along with the dominant reactions in the hadronic matter leading to photons are used. About half of the radiated photons are seen to have a thermal origin. The same treatment and the initial conditions provide a very good description to hadronic spectra measured by several groups and the intermediate mass dileptons measured by the NA50 experiment, lending a strong support to the conclusion that quark gluon plasma has been formed in these collisions. Predictions for RHIC and LHC energies are also given. (37 refs).
Kaplan, D.B.
1995-01-01
I give a brief and selective overview of QCD as it pertains to determining hadron structure, and the relevant directions in this field for nuclear theory. This document is intended to start discussion about priorities, not end it
Ferbel, T.
1976-01-01
Recent experimental results from studies of hadron interactions at Fermilab are surveyed. Elastic, total and charge-exchange cross section measurements, diffractive phenomena, and inclusive production, using nuclear as well as hydrogen targets, are discussed in these lectures
NONE
2006-07-01
The following topics were ealt with: Hadron physics with proton and deuteron probes, physics projects with Georgian participation, spin physics with antiprotons and leptons, spin filtering experiments, ISTC projects, technical issues for FAIR. (HSI)
Hadron multiplicities at COMPASS
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.
Hadronic production of glueballs
Lindenbaum, S.J.
1983-01-01
Local Gauge Invariance of SU(3)/sub c/ and color confinement would require that the only hadrons in the world be glueballs. However, when we add the quarks and obtain QCD it is experimentally clear that quark built states mask the expected glueballs. Thus discovery of glueballs is essential for the viability of QCD. Papers presented at the 1983 International Europhysics Conference on High Energy Physics on the hadronic production of glueballs and searches for glueballs are reviewed
Banfi, Andrea
2016-01-01
Jet physics is an incredibly rich subject detailing the narrow cone of hadrons and other particles produced by the hadronization of a quark or gluon in a particle physics or heavy ion experiment. This book is a general overview of jet physics for scientists not directly involved in the field. It presents the basic experimental and theoretical problems arising when dealing with jets, and describing the solutions proposed in recent years.
Hadronization in nuclear matter
Anton, G.; Blok, H.P.; Boudard, A.; Kopeliovich, B.
1993-01-01
The investigation of the space time structure of quark propagation and hadronization is proposed by studying particle production in deep-inelastic scattering of electrons from nucleons and nuclei with high statistics. A 15 to 30 GeV electron beam impinging on targets of hydrogen, deuterium, helium, carbon and lead is planned to be used and the final state hadrons are to be detected in a large solid angle device. (authors). 48 refs., 13 figs., 4 tabs
Martin, F.
1981-03-01
The x dependence of hadron structure functions is investigated. If quarks can exist in very low mass states (10 MeV for d and u quarks) the pion structure function is predicted to behave like (1-x) and not (1-x) 2 in a x-region around 1. Relativistic and non-relativistic quark bound state pictures of hadrons are considered together with their relation with the Q 2 evolution of structure functions. Good agreement with data is in general obtained
Greenberg, O.W.; Nelson, C.A.
1977-01-01
The evidence for a three-valued 'color' degree of freedom in hadron physics is reviewed. The structure of color models is discussed. Consequences of color models for elementary particle physics are discussed, including saturation properties of hadronic states, π 0 →2γ and related decays, leptoproduction, and lepton pair annihilation. Signatures are given which distinguish theories with isolated colored particles from those in which color is permanently bound. (Auth.)
Total Hadronic Cross-Section of Photon-Photon Interactions at LEP
Abbiendi, G.; Alexander, G.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barillari, T.; Barlow, Roger J.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bloodworth, I.J.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couchman, J.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Davis, R.; De Jong, S.; de Roeck, A.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A.A.; Feld, L.; Fiedler, F.; Fierro, M.; Fleck, I.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hajdu, C.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Hargrove, C.K.; Harin-Dirac, M.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hobson, P.R.; Hocker, James Andrew; Hoffman, Kara Dion; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klier, A.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lauber, J.; Lawson, I.; Layter, J.G.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Poli, B.; Polok, J.; Przybycien, M.; Quadt, A.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schmitt, S.; Schoning, A.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, David M.; Strohmer, R.; Surrow, B.; Talbot, S.D.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wackerle, F.; Wagner, A.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; Wetterling, D.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Zacek, V.; Zer-Zion, D.
2000-01-01
The total hadronic cross-section sigma_gg(W) for the interaction of real photons, gg->hadrons, is measured for gg centre-of-mass energies 10 e+e-g*g* -> e+e- hardrons, using a luminosity function for the photon flux together with form factors for extrapolating to real photons (Q^2=0 GeV^2). The data were taken with the OPAL detector at LEP at e+e- centre-of-mass energies 161, 172 and 183 GeV. The cross-section sigma_gg(W) is compared with Regge factorisation and with the energy dependence observed in gp and pp interactions. The data are also compared to models which predict a faster rise of sigma_gg(W) compared to gp and pp interactions due to additional hard gg interactions not present in hadronic collisions.
Possible manifestation of long range forces in high energy hadron collisions
Kuraev, Eh.A.; Ferro, P.; Trentadue, L.
1997-01-01
Pion-pion and photon-photon scattering are discussed.. We obtain, starting from the impact representation introduced by Cheng and Wu a new contribution to the high energy hadron-hadron scattering amplitude for small transferred momentum q 2 of the form is (q 2 /m 4 )ln(-q 2 /m 2 ). This behaviour may be interpreted as a manifestation of long transverse-range forces between hadrons which, for ρ>> m -1 fall off as ρ -4 . We consider the examples of pion and photon scattering with photons converted in the intermediate state to two pairs of quarks interacting by exchanging two gluon colorless state. A phenomenological approach for proton impact factor is used to analyze proton-proton scattering. The analysis of the lowest order radiative corrections for the case of photon-photon scattering is done. We discuss the possibility of observing the effects of these long range forces
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; Comas, P; 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; Abbaneo, D; Alemany, R; Bazarko, A O; Bright-Thomas, P G; Cattaneo, M; Cerutti, F; 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; 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; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, E; Thomson, F; 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; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Martin, E B; 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; 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; 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; Blair, G A; Bryant, L M; 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; 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; Walsh, J; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G
1997-01-01
Two samples of exclusive semileptonic decays, 579 B0->D*+l-nu events and 261 B0->D+l-nu events, are selected from approximately 3.9 million hadronic Z decays collected by the ALEPH detector at LEP. From the reconstructed differential decay rate of each sample, the product of the hadronic form factor F(w) at zero recoil of the D(*)+ meson and the CKM matrix element |Vcb| are measured to be FD*+(1)|Vcb| = (31.9 +/- 1.8(stat) +/- 1.9(syst) ) Mail afs archive asis auth bin boot categ cern collab comments core date dev drdspool etc export external_repno filename ftp home kadb lib lost+found mail mbox mnt nfs nsr old_archive old_drdspool old_pub opt pages pcfs pub publi publitype reconfigure ref repno sbin share sys tit tmp usr var vmunix 10**-3, FD+(1)|Vcb| = (27.8 +/- 6.8(stat) +/- 6.5(syst) ) Mail afs archive asis auth bin boot categ cern collab comments core date dev drdspool etc export external_repno filename ftp home kadb lib lost+found mail mbox mnt nfs nsr old_archive old_drdspool old_pub opt pages pcfs pub...
B → Kl{sup +}l{sup -} decay at large hadronic recoil
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.
Meson widths and form factor at intermediate momentum transfer in nonperturbative QCD
Ioffe, B.L.; Smilga, A.V.
1982-01-01
A general method is proposed for the QCD based calculations of form factors at intermediate momentum transfer Q 2 and of the partial widths of the low-lying meson resonances. The basic idea is to use the QCD sum rules for the vertex functions. With this method the pion electromagnetic form factor along with electromagnetic form factors of rho- and A 1 mesons and transition form factors γπ → A 1 at 0.5 2 2 are calculated. The widths rho+2π and A 1 → rhoπ are also determined. +.he results are in a good agreement with experiment
Calculation of the Nucleon Axial Form Factor Using Staggered Lattice QCD
Meyer, Aaron S. [Fermilab; Hill, Richard J. [Perimeter Inst. Theor. Phys.; Kronfeld, Andreas S. [Fermilab; Li, Ruizi [Indiana U.; Simone, James N. [Fermilab
2016-10-14
The nucleon axial form factor is a dominant contribution to errors in neutrino oscillation studies. Lattice QCD calculations can help control theory errors by providing first-principles information on nucleon form factors. In these proceedings, we present preliminary results on a blinded calculation of $g_A$ and the axial form factor using HISQ staggered baryons with 2+1+1 flavors of sea quarks. Calculations are done using physical light quark masses and are absolutely normalized. We discuss fitting form factor data with the model-independent $z$ expansion parametrization.
Electromagnetic form factors of the ρ meson in light cone QCD sum rules
Aliev, T.M.; Savci, M.
2004-01-01
We investigate the electromagnetic form factors of the ρ meson in light cone QCD sum rules. We find that the ratio of the magnetic and charge form factors is larger than 2 at all values of Q 2 (Q 2 ≥0.5 GeV 2 ). The values of the individual form factors at fixed values of Q 2 predicted by the light cone QCD sum rules are quite different compared to the results of other approaches. These results can be checked in the future, when more precise data on ρ meson form factors is available
Up- and Down-Quark Contributions to the Nucleon Form Factors
Qattan I. A.
2014-03-01
Full Text Available Recent measurements of the neutron s electric to magnetic form factors ratio, Rn = µnGnE/GnM, up to 3.4 (GeV/c2 combined with existing Rp = µpGpE/GpM measurements in the same Q2 range allowed, for the first time, a separation of the up- and downquark contributions to the form factors at high Q2, as presented by Cates, et al.. Our analysis expands on the original work by including additional form factor data, applying two-photon exchange (TPE corrections, and accounting for the uncertainties associated with all of the form factor measurements.
Perturbative corrections to Λ_b→Λ form factors from QCD light-cone sum rules
Wang, Yu-Ming; Shen, Yue-Long
2016-01-01
We compute radiative corrections to Λ_b→Λ from factors, at next-to-leading logarithmic accuracy, from QCD light-cone sum rules with Λ_b-baryon distribution amplitudes. Employing the diagrammatic approach factorization of the vacuum-to-Λ_b-baryon correlation function is justified at leading power in Λ/m_b, with the aid of the method of regions. Hard functions entering the factorization formulae are identical to the corresponding matching coefficients of heavy-to-light currents from QCD onto soft-collinear effective theory. The universal jet function from integrating out the hard-collinear fluctuations exhibits richer structures compared with the one involved in the factorization expressions of the vacuum-to-B-meson correlation function. Based upon the QCD resummation improved sum rules we observe that the perturbative corrections at O(α_s) shift the Λ_b→Λ from factors at large recoil significantly and the dominant contribution originates from the next-to-leading order jet function instead of the hard coefficient functions. Having at hand the sum rule predictions for the Λ_b→Λ from factors we further investigate several decay observables in the electro-weak penguin Λ_b→Λ ℓ"+ℓ"− transitions in the factorization limit (i.e., ignoring the “non-factorizable' hadronic effects which cannot be expressed in terms of the Λ_b→Λ from factors), including the invariant mass distribution of the lepton pair, the forward-backward asymmetry in the dilepton system and the longitudinal polarization fraction of the leptonic sector.
Quark-model study of the hadron structure and the hadron-hadron interaction
Valcarce, A; Caramés, T F; Vijande, J; Garcilazo, H
2011-01-01
Recent results of hadron spectroscopy and hadron-hadron interaction within a quark model framework are reviewed. Higher order Fock space components are considered based on new experimental data on low-energy hadron phenomenology. The purpose of this study is to obtain a coherent description of the low-energy hadron phenomenology to constrain QCD phenomenological models and try to learn about low-energy realizations of the theory.
Artificial Neural Networks For Hadron Hadron Cross-sections
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
Unraveling the Structure of Hadrons with Effective Field Theories of QCD
Iain Stewart
2004-01-01
Effective Field theory is a powerful framework based on controlled expansions for problems with a natural separation of energy scales. This technique is particularly important for QCD, the theory of strong interactions, due to the vast diversity of phenomena that it describes. Stewart and collaborators have invented a new class of effective theories that can be used in processes with energetic hadrons. These Soft-Collinear Effective Theories provide a unified framework for describing hadronic processes which involve hard probes or the release of a large amount of energy. Many interesting issues about hadronic physics can be addressed with the soft-collinear effective theory. Examples include the size and shape of hadronic form factors, the universality of hadronic distribution functions for a plethora of processes, and the importance of subleading corrections at intermediate energy scales. Effective field theories allow these issues to be addressed using only the underlying symmetries and scales in QCD. Understanding these issues also has a direct impact on other areas of physics, such as on devising clean methods for the measurement of CP violation in the decay of B-mesons. Current progress on the soft-collinear effective theory and related methods is discussed in this report
Nonscaling parametrization of hadronic spectra and dual parton model
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
Measurement of $\\Delta^{++}$(1232) production in hadronic Z decays
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.
Implications of QCD for soft hadronic and nuclear processes
Hwa, R.C.
1981-01-01
Physical implications of QCD for strong forces in soft processes are discussed. Topics include long-range force, Van der Waals force, nuclear force, hadron and quark structures. In the absence of a reliable calculational scheme, phenomenological models have been built that incorporate QCD ideas as far as possible. In the framework of those models calculations have been made that provide an understanding of the soft processes in terms of quarks and gluons. We review recent work on nuclear potential, form factors at low Q 2 , pion decay constant, inclusive distribution of low p/sub T/, and radiation length of fast quark in nuclear matter
Light-cone quantized QCD and novel hadron phenomenology
Brodsky, S.J.
1997-09-01
The authors reviews progress made in solving gauge theories such as collinear quantum chromodynamics using light-cone Hamiltonian methods. He also shows how the light-cone Fock expansion for hadron wavefunctions can be used to compute operator matrix elements such as decay amplitudes, form factors, distribution amplitudes, and structure functions, and how it provides a tool for exploring novel features of QCD. The author also reviews commensurate scale relations, leading-twist identities which relate physical observables to each other, thus eliminating renormalization scale and scheme ambiguities in perturbative QCD predictions
Improved determination of hadron matrix elements using the variational method
Dragos, J.; Kamleh, W.; Leinweber, D.B.; Zanotti, J.M.; Rakow, P.E.L.; Young, R.D.; Adelaide Univ.
2015-11-01
The extraction of hadron form factors in lattice QCD using the standard two- and three-point correlator functions has its limitations. One of the most commonly studied sources of systematic error is excited state contamination, which occurs when correlators are contaminated with results from higher energy excitations. We apply the variational method to calculate the axial vector current g A and compare the results to the more commonly used summation and two-exponential fit methods. The results demonstrate that the variational approach offers a more efficient and robust method for the determination of nucleon matrix elements.
From parity violation to hadronic structure and more
Jager, K; Kox, S; Lhuillier, D; Maas, F; Page, S; Papanicolas, C; Stiliaris, S; Wiele, J; 3rd International Workshop on From Parity Violation to Hadronic Structure and More (PAVI06); PAVI 06; PAVI 2006
2007-01-01
This book contains the proceedings of the third international workshop on “From Parity Violation to Hadronic Structure and more ...” which was held from May 16 to May 20, 2006, at the George Eliopoulos conference center on the Greek island of Milos. It is part of a series that started in Mainz in 2002 and was followed by a second workshop in Grenoble in 2004. While originally initiated by the extraction of the strangeness contribution to the electromagnetic form factors of the nucleon, the workshop series has continuously broadened the focus to the application of Parity Violation using hadronic probes and to Parity Violation experiments in atomic physics. Meanwhile there have been many exciting new proposals for using Parity Violation in other areas like in the search for new physics beyond the standard model or in exploring hadron structure. There are also close connections to the open question on the size of the two photon exchange amplitude. Fifty years after the 1956 proposal of Lee and Yang to test t...
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...
Hadronic light-by-light scattering contribution to the muon g-2
Nyffeler, A.
2010-01-01
We review recent developments concerning the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon. We first discuss why fully off-shell hadronic form factors should be used for the evaluation of this contribution to the g-2. We then reevaluate the numerically dominant pion-exchange contribution in the framework of large-N C QCD, using an off-shell pion-photon-photon form factor which fulfills all QCD short-distance constraints,in particular, a new short-distance constraint on the off-shell form factor at the external vertex in g-2, which relates the form factor to the quark condensate magnetic susceptibility in QCD. Combined with available evaluations of the other contributions to hadronic light-by-light scattering this leads to the new result α μ LbyL;had =(116 ± 40) x 10 -11 , with a conservative error estimate in view of the many still unsolved problems. Some potential ways for further improvements are briefly discussed as well. For the electron we obtain the new estimate α e LbyL;had =(3.9 ± 1.3) x 10 -14 . (author)
Form factors in quantum integrable models with GL(3)-invariant R-matrix
Pakuliak, S., E-mail: pakuliak@theor.jinr.ru [Laboratory of Theoretical Physics, JINR, 141980 Dubna, Moscow Reg. (Russian Federation); Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Moscow Reg. (Russian Federation); Institute of Theoretical and Experimental Physics, 117259 Moscow (Russian Federation); Ragoucy, E., E-mail: eric.ragoucy@lapth.cnrs.fr [Laboratoire de Physique Théorique LAPTH, CNRS and Université de Savoie, BP 110, 74941 Annecy-le-Vieux Cedex (France); Slavnov, N.A., E-mail: nslavnov@mi.ras.ru [Steklov Mathematical Institute, Moscow (Russian Federation)
2014-04-15
We study integrable models solvable by the nested algebraic Bethe ansatz and possessing GL(3)-invariant R-matrix. We obtain determinant representations for form factors of off-diagonal entries of the monodromy matrix. These representations can be used for the calculation of form factors and correlation functions of the XXX SU(3)-invariant Heisenberg chain.
Recoil of the pion-surrounded nucleon bag and axial form factors
Klabucar, D.; Picek, I.
1984-03-01
A recent method of boosting the bag is extended to the pion-surrounded nucleon bag and developed for the calculation of low-energy nucleon form factors. The usefulness of the method is illustrated by the induced pseudoscalar form factor where both the inclusion of the pion field and the non-vanishing momentum transfer are necessary. (Auth.)
Gluing operation and form factors of local operators in N = 4 Super Yang-Mills theory
Bolshov, A. E.
2018-04-01
The gluing operation is an effective way to get form factors of both local and non-local operators starting from different representations of on-shell scattering amplitudes. In this paper it is shown how it works on the example of form factors of operators from stress-tensor operator supermultiplet in Grassmannian and spinor helicity representations.
Study of the hadronisation process from single hadron and hadron-pair production in SIDIS at COMPASS
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...
48 CFR 247.372 - DD Form 1654, Evaluation of Transportation Cost Factors.
2010-10-01
... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false DD Form 1654, Evaluation... Transportation in Supply Contracts 247.372 DD Form 1654, Evaluation of Transportation Cost Factors. Contracting personnel may use the DD Form 1654 to furnish information to the transportation office for development of...
Identified hadron spectra from PHOBOS
Veres, Gábor I.; the PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wysłouch, B.; Zhang, J.
2004-08-01
Transverse momentum spectra of pions, kaons and protons, as well as antiparticle to particle ratios near mid-rapidity from d+Au collisions at \\sqrt{sNN} = 200 GeV have been measured by the PHOBOS experiment at RHIC. The transverse momentum range of particle identification was extended to beyond 3 GeV/c using the TOF detector and a new trigger system. The pseudorapidity dependence of the nuclear modification factor for charged hadrons in d+Au collisions is presented.
Effects of the d-state quarks on the nucleon electric form factors
Oh, Y.J.; Kong, K.J.; Cheon, I.T.
1987-11-01
Considering the d-orbital excitation of a quark in the bag, we calculate the nucleon electric form factors in the cloudy bag model. In these calculations, we have taken into account the πNN, πΔN and πγ form factors though neglecting the c.m. correction. It turns out that the neutron charge form factor is very sensitive to the d-state quark admixture in the overall region of the momentum transfer but the proton charge form factor remains unchanged. Taking the d-state quark admixture in the intermediate state baryons, we can obtain the nucleon rms radii in remarkable agreement with the experimental values. We also investigate the roles of Δ particles in the nucleon charge form factors. (author). 20 refs, 10 figs
Future Measurements of the Nucleon Elastic Electromagnetic Form Factors at Jefferson Lab
Gilfoyle, Gerard
2018-01-01
The elastic, electromagnetic form factors are fundamental observables that describe the internal structure of protons, neutrons, and atomic nuclei. Jefferson Lab in the United States has completed the 12 GeV Upgrade that will open new opportunities to study the form factors. A campaign to measure all four nucleon form factors (electric and magnetic ones for both proton and neutron) has been approved consisting of seven experiments in Halls A, B, and C. The increased energy of the electron beam will extend the range of precision measurements to higher Q2 for all four form factors together. This combination of measurements will allow for the decomposition of the results into their quark components and guide the development of a QCD-based understanding of nuclei in the non-perturbative regime. I will present more details on the 12 GeV Upgrade, the methods used to measure the form factors, and what we may learn.
Separating form factor and nuclear model effects in quasielastic neutrino-nucleus scattering
Wieske, Joseph
2017-09-01
When studying neutrino oscillations an understanding of charged current quasielastic (CCQE) neutrino-nucleus scattering is imperative. This interaction depends on a nuclear model as well as knowledge of form factors. In the past, CCQE data from the MiniBooNE experiment was analyzed assuming the Relativistic Fermi Gas (RFG) nuclear model, an axial dipole form factor in, and using the the z-expansion for the axial form factor in. We present the first analysis that combines a non-RFG nuclear model, in particular the Correlated Fermi Gas nuclear model (CFG) of, and the z expansion for the axial form factor. This will allow us to separate form factor and nuclear model effects in CCQE scattering. This project was supported through the Wayne State University REU program under NSF Grant PHY-1460853 and by the DOE Grant DE-SC0007983.
Skyrme-model πNN form factor and nucleon-nucleon interaction
Holzwarth, G.; Machleidt, R.
1997-01-01
We apply the strong πNN form factor, which emerges from the Skyrme model, in the two-nucleon system using a one-boson-exchange (OBE) model for the nucleon-nucleon (NN) interaction. Deuteron properties and phase parameters of NN scattering are reproduced well. In contrast to the form factor of monopole shape that is traditionally used in OBE models, the Skyrme form factor leaves low-momentum transfers essentially unaffected while it suppresses the high-momentum region strongly. It turns out that this behavior is very appropriate for models of the NN interaction and makes it possible to use a soft pion form factor in the NN system. As a consequence, the πN and the NN systems can be described using the same πNN form factor, which is impossible with the monopole. copyright 1997 The American Physical Society
The scalar and electromagnetic form factors of the nucleon in dispersively improved Chiral EFT
Alarcon, Jose Manuel [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2018-04-01
We present a method for calculating the nucleon form factors of G-parity-even operators. This method combines chiral effective field theory (χEFT) and dispersion theory. Through unitarity we factorize the imaginary part of the form factors into a perturbative part, calculable with χEFT, and a non-perturbative part, obtained through other methods. We consider the scalar and electromagnetic (EM) form factors of the nucleon. The results show an important improvement compared to standard chiral calculations, and can be used in analysis of the low-energy properties of the nucleon.
Heavy-to-light form factors for non-relativistic bound states
Bell, G.; Feldmann, Th.
2007-01-01
We investigate transition form factors between non-relativistic QCD bound states at large recoil energy. Assuming the decaying quark to be much heavier than its decay product, the relativistic dynamics can be treated according to the factorization formula for heavy-to-light form factors obtained from the heavy-quark expansion in QCD. The non-relativistic expansion determines the bound-state wave functions to be Coulomb-like. As a consequence, one can explicitly calculate the so-called 'soft-overlap' contribution to the transition form factor
Palano, Antimo
2018-01-01
The LHCb experiment is designed to study the properties and decays of heavy ﬂavored hadrons produced in pp collisions at the LHC. The data collected in the LHC Run I enables precision spectroscopy studies of beauty and charm hadrons. The latest results on spectroscopy of conventional and exotic hadrons are reviewed. In particular the discovery of the ﬁrst charmonium pentaquark states in the $J/\\psi p$ system, the possible existence of four-quark states decaying to $J/\\psi \\phi$ and the conﬁrmation of resonant nature of the $Z_c(4430)^−$ mesonic state are discussed. In the sector of charmed baryons, the observation of ﬁve new $\\Omega_c$ states, the observation of the $\\Xi^+_{cc}$ and the study of charmed baryons decaying to $D^0 p$ are presented.
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)
High energy hadron-hadron collisions. Annual progress report
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
Engaging undergraduate students in hadron physics research and instrumentation
Horn, Tanja
2017-09-01
Nuclear physics research is fundamental to our understanding of the visible universe and at the same time intertwined with our daily life. Nuclear physics studies the origin and structure of the atomic nuclei in terms of their basic constituents, the quarks and gluons. Atoms and molecules would not exist without underlying quark-gluon interactions, which build nearly all the mass of the visible universe from an assembly of massless gluons and nearly-massless quarks. The study of hadron structure with electromagnetic probes through exclusive and semi-inclusive scattering experiments carried out at the 12 GeV Jefferson Laboratory plays an important role in this effort. In particular, planned precision measurements of pion and kaon form factors and longitudinal-transverse separated deep exclusive pion and kaon electroproduction cross sections to the highest momentum transfers achievable play an important role in understanding hadron structure and masses and provide essential constraints for 3D hadron imaging. While a growing fraction of nuclear physics research is carried out at large international laboratories, individual university research groups play critical roles in the success of that research. These include data analysis projects and the development of state-of-the-art instrumentation demanded by increasingly sophisticated experiments. These efforts are empowered by the creativity of university faculty, staff, postdocs, and provide students with unique hands-on experience. As an example, an aerogel Cherenkov detector enabling strangeness physics research in Hall C at Jefferson Lab was constructed at the Catholic University of America with the help of 16 undergraduate and high school students. The ''Conference Experience for Undergraduates'' (CEU) provides a venue for these students who have conducted research in nuclear physics. This presentation will present the experiences of one of the participants in the first years of the CEU, her current research program
Form factors of Ising spin and disorder fields on the Poincare disc
Doyon, Benjamin
2004-01-01
Using recent results concerning form factors of certain scaling fields in the massive Dirac theory on the Poincare disc, we find expressions for the form factors of Ising spin and disorder fields in the massive Majorana theory on the Poincare disc. In particular, we verify that these recent results agree with the factorization properties of the fields in the Dirac theory representing tensor products of spin and of disorder fields in the Majorana theory
Probing dense matter with strange hadrons
Rafelski, Johann; Rafelski, Johann; Letessier, Jean
2002-01-01
Analysis of hadron production experimental data allows to understand the properties of the dense matter fireball produced in relativistic heavy ion collisions. We interpret the analysis results and argue that color deconfined state has been formed at highest CERN-SPS energies and at BNL-RHIC.
Quigg, C.
1982-11-01
The subject of hadron jet studies, to judge by the work presented at this workshop, is a maturing field which is still gathering steam. The very detailed work being done in lepton-lepton and lepton-hadron collisions, the second-generation measurements being carried out at Fermilab, the CERN SPS, and the ISR, and the very high energy hard scatterings being observed at the CERN Collider all show enormous promise for increased understanding. Perhaps we shall yet reach that long-sought nirvana in which high-p/sub perpendicular/ collisions become truly simple
Ogava, S.; Savada, S.; Nakagava, M.
1983-01-01
Composite models of hadrons are considered. The main attention is paid to the Sakata, S model. In the framework of the model it is presupposed that proton, neutron and Λ particle are the fundamental particles. Theoretical studies of unknown fundamental constituents of a substance have led to the creation of the quark model. In the framework of the quark model using the theory of SU(6)-symmetry the classification of mesons and baryons is considered. Using the quark model relations between hadron masses, their spins and electromagnetic properties are explained. The problem of three-colour model with many flavours is briefly presented
Anon.
1987-01-01
'Hadron facilities' – high intensity (typically a hundred microamps), medium energy (30-60 GeV) machines producing intense secondary beams of pions, kaons, etc., are being widely touted as a profitable research avenue to supplement what is learned through the thrust for higher and higher energies. This interest was reflected at an International Workshop on Hadron Facility Technology, held in Santa Fe, New Mexico. As well as invited talks describing the various projects being pushed in the US, Europe and Japan, the meeting included working groups covering linacs, beam dynamics, hardware, radiofrequency, polarized beams and experimental facilities
Large transverse momenta phenomena in hadron-hadron collisions
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)
Hadron chemistry in heavy ion collisions
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 neutron electric form factor to Q² = 1.45 (GeV/c)²
Plaster, Bradley [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
2004-02-01
The nucleon elastic electromagnetic form factors are fundamental quantities needed for an understanding of nucleon and nuclear electromagnetic structure. The evolution of the Sachs electric and magnetic form factors with Q^{2}, the square of the four-momentum transfer, is related to the distribution of charge and magnetization within the nucleon. High precision measurements of the nucleon form factors are essential for stringent tests of our current theoretical understanding of confinement within the nucleon. Measurements of the neutron form factors, in particular, those of the neutron electric form factor, have been notoriously difficult due to the lack of a free neutron target and the vanishing integral charge of the neutron. Indeed, a precise measurement of the neutron electric form factor has eluded experimentalists for decades; however, with the advent of high duty-factor polarized electron beam facilities, experiments employing polarization degrees of freedom have finally yielded the first precise measurements of this fundamental quantity. Following a general overview of the experimental and theoretical status of the nucleon form factors, a detailed description of an experiment designed to extract the neutron electric form factor from measurements of the neutron's recoil polarization in quasielastic 2H(e, e')1H scattering is presented. The experiment described here employed the Thomas Jefferson National Accelerator Facility's longitudinally polarized electron beam, a magnetic spectrometer for detection of the scattered electron, and a neutron polarimeter designed specifically for this experiment. Measurements were conducted at three Q^{2} values of 0.45, 1.13, and 1.45 (GeV/c)^{2}, and the final results extracted from an analysis of the data acquired in this experiment are reported and compared with recent theoretical predictions for the nucleon form factors.
Quark models in hadron physics
Phatak, Shashikant C.
2007-01-01
In this talk, we review the role played by the quark models in the study of interaction of strong, weak and electromagnetic probes with hadrons at intermediate and high momentum transfers. By hadrons, we mean individual nucleons as well as nuclei. We argue that at these momentum transfers, the structure of hadrons plays an important role. The hadron structure of the hadrons is because of the underlying quark structure of hadrons and therefore the quark models play an important role in determining the hadron structure. Further, the properties of hadrons are likely to change when these are placed in nuclear medium and this change should arise from the underlying quark structure. We shall consider some quark models to look into these aspects. (author)
A Factor Analytic Study of the Coopersmith Self-Esteem Inventory Adult Short Form.
Haines, Janet; Wilson, George V.
1988-01-01
A factor analysis was conducted on the Coopersmith Self-Esteem Inventory-Adult Short Form using 237 college students and 43 female office workers in Australia. Factors were found corresponding with three of the four subscales: general self, social self-peers, and home-parents (family). No factor related to the school-academic (work) subscale. (SLD)
Nucleon electromagnetic form factors using lattice simulations at the physical point
Alexandrou, C.; Cyprus Univ., Nicosia; Constantinou, M.; Hadjiyiannakou, K.; Kallidonis, C.; Koutsou, G.; Jansen, K.; Vaquero Aviles-Casco, A.
2017-01-01
We present results for the nucleon electromagnetic form factors using an ensemble of maximally twisted mass clover-improved fermions with pion mass of about 130 MeV. We use multiple sink-source separations and three analysis methods to probe ground-state dominance. We evaluate both the connected and disconnected contributions to the nucleon matrix elements. We find that the disconnected quark loop contributions to the isoscalar matrix elements are small giving an upper bound of up to 2% of the connected and smaller than its statistical error. We present results for the isovector and isoscalar electric and magnetic Sachs form factors and the corresponding proton and neutron form factors. By fitting the momentum dependence of the form factors to a dipole form or to the z-expansion we extract the nucleon electric and magnetic radii, as well as, the magnetic moment. We compare our results to experiment as well as to other recent lattice QCD calculations.
Nucleon electromagnetic form factors using lattice simulations at the physical point
Alexandrou, C. [The Cyprus Institute, Nicosia (Cyprus). Computation-based Science and Technology Research Center; Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; Constantinou, M. [Temple Univ., Philadelphia, PA (United States). Dept. of Physics; Hadjiyiannakou, K.; Kallidonis, C.; Koutsou, G. [The Cyprus Institute, Nicosia (Cyprus). Computation-based Science and Technology Research Center; Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Vaquero Aviles-Casco, A. [Utah Univ., Salt Lake City, UT (United States). Dept. of Physics and Astronomy
2017-09-20
We present results for the nucleon electromagnetic form factors using an ensemble of maximally twisted mass clover-improved fermions with pion mass of about 130 MeV. We use multiple sink-source separations and three analysis methods to probe ground-state dominance. We evaluate both the connected and disconnected contributions to the nucleon matrix elements. We find that the disconnected quark loop contributions to the isoscalar matrix elements are small giving an upper bound of up to 2% of the connected and smaller than its statistical error. We present results for the isovector and isoscalar electric and magnetic Sachs form factors and the corresponding proton and neutron form factors. By fitting the momentum dependence of the form factors to a dipole form or to the z-expansion we extract the nucleon electric and magnetic radii, as well as, the magnetic moment. We compare our results to experiment as well as to other recent lattice QCD calculations.
Hadron Therapy for Cancer Treatment
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.
An experimental survey of the factors that affect leaching from low-level radioactive waste forms
Dougherty, D.R.; Pietrzak, R.F.; Fuhrmann, M.; Colombo, P.
1988-09-01
This report represents the results of an experimental survey of the factors that affect leaching from several types of solidified low-level radioactive waste forms. The goal of these investigations was to determine those factors that accelerate leaching without changing its mechanism(s). Typically, although not in every case,the accelerating factors include: increased temperature, increased waste loading (i.e., increased waste to binder ratio), and decreased size (i.e., decreased waste form volume to surface area ratio). Additional factors that were studied were: increased leachant volume to waste form surface area ratio, pH, leachant composition (groundwaters, natural and synthetic chelating agents), leachant flow rate or replacement frequency and waste form porosity and surface condition. Other potential factors, including the radiation environment and pressure, were omitted based on a survey of the literature. 82 refs., 236 figs., 13 tabs
Asymptotic behavior of composite-particle form factors and the renormalization group
Duncan, A.; Mueller, A.H.
1980-01-01
Composite-particle form factors are studied in the limit of large momentum transfer Q. It is shown that in models with spinor constituents and either scalar or gauge vector gluons, the meson electromagnetic form factor factorizes at large Q 2 and is given by independent light-cone expansions on the initial and final meson legs. The coefficient functions are shown to satisfy a Callan-Symanzik equation. When specialized to quantum chromodynamics, this equation leads to the asymptotic formula of Brodsky and Lepage for the pion electromagnetic form factor. The nucleon form factors G/sub M/(Q 2 ), G/sub E/(Q 2 ) are also considered. It is shown that momentum flows which contribute to subdominant logarithms in G/sub M/(Q 2 ) vitiate a conventional renormalization-group interpretation for this form factor. For large Q 2 , the electric form factor G/sub E/(Q 2 ) fails to factorize, so that a renormalization-group treatment seems even more unlikely in this case
Theussl, L.; Noguera, S.; Amghar, A.; Desplanques, B.
2003-01-01
The effect of different boost expressions, pertinent to the instant, front and point forms of relativistic quantum mechanics, is considered for the calculation of the ground-state form factor of a two-body system in simple scalar models. Results with a Galilean boost as well as an explicitly covariant calculation based on the Bethe-Salpeter approach are given for comparison. It is found that the present so-called point-form calculations of form factors strongly deviate from all the other ones. This suggests that the formalism which underlies them requires further elaboration. A proposition in this sense is made. (author)
A measurement of the space-like pion electromagnetic form factor
Amendolia, S.R.; Badelek, B.; Batignani, G.; Bedeschi, F.; Bertolucci, E.; Bettoni, D.; Bosisio, L.; Bradaschia, C.; Dell'Orso, M.; Fidecaro, F.; Foa, L.; Focardi, E.; Giazotto, A.; Giorgi, M.A.; Marrocchesi, P.S.; Menzione, A.; Ristori, L.; Scribano, A.; Tonelli, G.; Triggiani, G.; Codino, A.; Enorini, M.; Fabbri, F.L.; Laurelli, P.; Satta, L.; Spillantini, P.; Zallo, A.
1986-01-01
The pion form factor has been measured in the space-like q 2 region 0.014 to 0.26 (GeV/c) 2 by scattering 300 GeV pions from the electrons of a liquid hydrogen target. A detailed description is given of the apparatus, data analysis and corrections to the data. The mean square charge radius extracted from the data is model-dependent. We find that a form which includes a realistic description of the form factor phase gives a similar result to the naive pole form, and conclude π 2 >=0.439±0.008 fm 2 . (orig.)
Hadronization of dense partonic matter
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.
Measurement of the form factor in the decay K+ → π0e+vsub(e)
Martyn, H.U.
1974-01-01
Following an introduction into the theory of the K(l3) decay, the fundamentals for the measuring methods of the form factor are derived. The choice of the quantity of nuclear events, the problems of the detection probabilities and of the background, and the form factor analysis are dealt with in detail. The analysis shows that the form factor can be very well described by a linear parametrization. The upper limits for scalar and tensorial interaction contributions are given; these results confirm the validity of the V-A theory also for strangeness-changing decays. (BJ/LH) [de
Strange mesons and kaon-to-pion transition form factors from holography
Abidin, Zainul; Carlson, Carl E.
2009-01-01
We present a calculation of the K l3 transition form factors using the AdS/QCD correspondence. We also solidify and extend our ability to calculate quantities in the flavor-broken versions of AdS/QCD. The normalization of the form factors is a crucial ingredient for extracting |V us | from data, and the results obtained here agree well with results from chiral perturbation theory and lattice gauge theory. The slopes and curvature of the form factors agree well with the data, and with what results are available from other methods of calculation.
The B → D*lv form factor at zero recoil
Simone, J.N.; Hashimoto, S.; El-Khadra, A.X.; Kronfeld, A.S.; Mackenzie, P.B.; Ryan, S.M.
2000-01-01
We describe a model independent lattice QCD method for determining the deviation from unity for h A1 (1), the B → D*lv form factor at zero recoil. We extend the double ratio method previously used to determine the B → Dlv form factor. The bulk of statistical and systematic errors cancel in the double ratios we consider, yielding form factors which promise to reduce present theoretical uncertainties in the determination of parallel V cb parallel. We present results from a prototype calculation at a single lattice spacing corresponding to β = 5.7
Delta and Omega electromagnetic form factors in a Dyson-Schwinger/Bethe-Salpeter approach
Diana Nicmorus, Gernot Eichmann, Reinhard Alkofer
2010-12-01
We investigate the electromagnetic form factors of the Delta and the Omega baryons within the Poincare-covariant framework of Dyson-Schwinger and Bethe-Salpeter equations. The three-quark core contributions of the form factors are evaluated by employing a quark-diquark approximation. We use a consistent setup for the quark-gluon dressing, the quark-quark bound-state kernel and the quark-photon interaction. Our predictions for the multipole form factors are compatible with available experimental data and quark-model estimates. The current-quark mass evolution of the static electromagnetic properties agrees with results provided by lattice calculations.
On form factors of the conjugated field in the non-linear Schroedinger model
Kozlowski, K.K.
2011-05-15
Izergin-Korepin's lattice discretization of the non-linear Schroedinger model along with Oota's inverse problem provides one with determinant representations for the form factors of the lattice discretized conjugated field operator. We prove that these form factors converge, in the zero lattice spacing limit, to those of the conjugated field operator in the continuous model. We also compute the large-volume asymptotic behavior of such form factors in the continuous model. These are in particular characterized by Fredholm determinants of operators acting on closed contours. We provide a way of defining these Fredholm determinants in the case of generic paramaters. (orig.)
On the large-Q2 behavior of the pion transition form factor
Gernot Eichmann
2017-11-01
Full Text Available We study the transition of non-perturbative to perturbative QCD in situations with possible violations of scaling limits. To this end we consider the singly- and doubly-virtual pion transition form factor π0→γγ at all momentum scales of symmetric and asymmetric photon momenta within the Dyson–Schwinger/Bethe–Salpeter approach. For the doubly virtual form factor we find good agreement with perturbative asymptotic scaling laws. For the singly-virtual form factor our results agree with the Belle data. At very large off-shell photon momenta we identify a mechanism that introduces quantitative modifications to Efremov–Radyushkin–Brodsky–Lepage scaling.
Johnson, R.C.
1980-01-01
High energy and small momentum transfer 2 'yields' 2 hadronic scattering processes are described in the physical framework of particle exchange. Particle production in high energy collisions is considered with emphasis on the features of inclusive reactions though with some remarks on exclusive processes. (U.K.)
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.
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.
Buskulic, Damir; De Bonis, I; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Ariztizabal, F; Chmeissani, M; Crespo, J M; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Gaitan, V; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; 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; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Engelhardt, A; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Markou, C; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wiedenmann, W; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Bardadin-Otwinowska, Maria; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Saadi, F; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Kyriakis, A; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Passalacqua, L; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Delfino, M C; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Pepé-Altarelli, M; Dorris, S J; Halley, A W; ten Have, I; Knowles, I G; Lynch, J G; Morton, W T; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Smith, M G; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Braun, O; Geweniger, C; Graefe, G; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Colling, D J; Dornan, Peter J; Konstantinidis, N P; Moneta, L; Moutoussi, A; Nash, J; San Martin, G; Sedgbeer, J K; Stacey, A M; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Raab, J; Renk, B; Sander, H G; Wanke, R; 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; Thulasidas, M; Nicod, D; Payre, P; Rousseau, D; Talby, M; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Brown, D; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wolf, G; Alemany, R; Boucrot, J; Callot, O; Cordier, A; Courault, F; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Musolino, G; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Abbaneo, 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; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Triggiani, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Mir, L M; Perrodo, P; Strong, J A; Bertin, V; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Edwards, M; Maley, P; Norton, P R; Thompson, J C; 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; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Cartwright, S L; Combley, F; Dawson, I; Köksal, A; Letho, M; Newton, W M; Rankin, C; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Feigl, E; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G
1996-01-01
From 64492 selected \\tau-pair events, produced at the Z^0 resonance, the measurement of the tau decays into hadrons from a global analysis using 1991, 1992 and 1993 ALEPH data is presented. Special emphasis is given to the reconstruction of photons and \\pi^0's, and the removal of fake photons. A detailed study of the systematics entering the \\pi^0 reconstruction is also given. A complete and consistent set of tau hadronic branching ratios is presented for 18 exclusive modes. Most measurements are more precise than the present world average. The new level of precision reached allows a stringent test of \\tau-\\mu universality in hadronic decays, g_\\tau/g_\\mu \\ = \\ 1.0013 \\ \\pm \\ 0.0095, and the first measurement of the vector and axial-vector contributions to the non-strange hadronic \\tau decay width: R_{\\tau ,V} \\ = \\ 1.788 \\ \\pm \\ 0.025 and R_{\\tau ,A} \\ = \\ 1.694 \\ \\pm \\ 0.027. The ratio (R_{\\tau ,V} - R_{\\tau ,A}) / (R_{\\tau ,V} + R_{\\tau ,A}), equal to (2.7 \\pm 1.3) \\ \\%, is a measure of the importance of Q...
Eytier, Jean-Louis
2009-01-01
Qu'aurait-il proposé comme solutions face aux déboires du LHC, le grand collisionneur du hadrons du CERN, arrêté peu après son démarrage à l'automne 2008? Lucien Edmond André Montanet était un des grands de la physique des particules. (2 pages)
manifestly the symmetries of the underlying theory of strong interactions, i.e. ..... Note that such a picture, in which the self-energies of hadrons are generated by ..... An experimental verification of this prediction would be a major step forward in.
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
Hirstius, Andreas
2008-01-01
Plans for dealing with the torrent of data from the Large Hadron Collider's detectors have made the CERN particle-phycis lab, yet again, a pioneer in computing as well as physics. The author describes the challenges of processing and storing data in the age of petabyt science. (4 pages)
2007-01-01
"In the spring 2008, the Large Hadron Collider (LHC) machine at CERN (the European Particle Physics laboratory) will be switched on for the first time. The huge machine is housed in a circular tunnel, 27 km long, excavated deep under the French-Swiss border near Geneva." (1,5 page)
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
Interaction between droplets in a ternary microemulsion evaluated by the relative form factor method
Nagao, Michihiro; Seto, Hideki; Yamada, Norifumi L.
2007-01-01
This paper describes the concentration dependence of the interaction between water droplets coated by a surfactant monolayer using the contrast variation small-angle neutron scattering technique. In the first part, we explain the idea of how to extract a relatively model free structure factor from the scattering data, which is called the relative form factor method. In the second part, the experimental results for the shape of the droplets (form factor) are described. In the third part the relatively model free structure factor is shown, and finally the concentration dependence of the interaction potential between droplets is discussed. The result indicates the validity of the relative form factor method, and the importance of the estimation of the model free structure factor to discuss the nature of structure formation in microemulsion systems
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
Physics at Hadronic Colliders (4/4)
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. 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. 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. 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)
Hadron physics from lattice QCD
Schaefer, Andreas [Regensburg Univ. (Germany). Inst. for Theoretical Physics
2016-11-01
Particle physics experiments at modern high luminosity particle accelerators achieve orders of magnitude higher count rates than what was possible ten or twenty years ago. This extremely large statistics allows to draw far reaching conclusions even from minute signals, provided that these signals are well understood by theory. This is, however, ever more difficult to achieve. Presently, technical and scientific progress in general and experimental progress in particle physics in particular, shows typically an exponential growth rate. For example, data acquisition and analysis are, among many other factor, driven by the development of ever more efficient computers and thus by Moore's law. Theory has to keep up with this development by also achieving an exponential increase in precision, which is only possible using powerful computers. This is true for both types of calculations, analytic ones as, e.g., in quantum field perturbation theory, and purely numerical ones as in Lattice QCD. As stated above such calculations are absolutely indispensable to make best use of the extremely costly large particle physics experiments. Thus, it is economically reasonable to invest a certain percentage of the cost of accelerators and experiments in related theory efforts. The basic ideas behind Lattice QCD simulations are the following: Because quarks and gluons can never be observed individually but are always ''confined'' into colorless hadrons, like the proton, all quark-gluon states can be expressed in two different systems of basis states, namely in a quark-gluon basis and the basis of hadron states. The proton, e.g., is an eigenstate of the latter, a specific quark-gluon configuration is part of the former. In the quark-gluon basis a physical hadron, like a proton, is given by an extremely complicated multi-particle wave function containing all effects of quantum fluctuations. This state is so complicated that it is basically impossible to model it
Meson form factors and covariant three-dimensional formulation of composite model
Skachkov, N.B.; Solovtsov, I.L.
1978-01-01
An approach is developed which is applied in the framework of the relativistic quark model to obtain explicit expressions for meson form factors in terms of covariant wave functions of the two-quark system. These wave functions obey the two-particle quasipotential equation in which the relative motion of quarks is singled out in a covariant way. The exact form of the wave functions is found using the transition to the relativistic configurational representation with the help of the harmonic analysis on the Lorentz group instead of the usual Fourier expansion and then solving the relativistic difference equation thus obtained. The expressions found for form factors are transformed into the three-dimensional covariant form which is a direct geometrical relativistic generalization of analogous expressions of the nonrelativistic quantum mechanics and provides the decrease of the meson form factor by the Fsub(π)(t) approximately t -1 law as -t infinity, in the Coulomb field
Relativistic corrections to the form factors of Bc into P-wave orbitally excited charmonium
Zhu, Ruilin
2018-06-01
We investigated the form factors of the Bc meson into P-wave orbitally excited charmonium using the nonrelativistic QCD effective theory. Through the analytic computation, the next-to-leading order relativistic corrections to the form factors were obtained, and the asymptotic expressions were studied in the infinite bottom quark mass limit. Employing the general form factors, we discussed the exclusive decays of the Bc meson into P-wave orbitally excited charmonium and a light meson. We found that the relativistic corrections lead to a large correction for the form factors, which makes the branching ratios of the decay channels B (Bc ± →χcJ (hc) +π± (K±)) larger. These results are useful for the phenomenological analysis of the Bc meson decays into P-wave charmonium, which shall be tested in the LHCb experiments.
Applicability of perturbative QCD and NLO power corrections for the pion form factor
Yeh Tsungwen
2002-01-01
As is well recognized, the asymptotic of the perturbative QCD prediction for the pion form factor is much smaller than the upper end of the data. We investigate this problem. We first evaluate the next-to-leading-order (NLO) power correction for the pion form factor. The corrected form factor contains nonperturbative parameters which are determined from a χ 2 fit to the data. Interpreting these parameters leads to the fact that the involved strong interaction coupling constant should be identified as an effective coupling constant under a nonperturbative QCD vacuum. If the scale associated with the effective coupling constant is identified as 2 Q 2 , then Q 2 , the momentum transfer square for the pion form factor to be measured, can have a value about 1 GeV 2 , and , the averaged momentum fraction variable, can locate around 0.5. This circumstance is consistent with the asymptotic model for the pion wave function
Study of the electromagnetic form factors of Helium-3 and Tritium nuclei by electron scattering
Amroun, A.
1989-01-01
Accurate measurements of the tritium electromagnetic form factor demonstrated that, when the exchange currents are included, the theoretical and the experimental data are in agreement. Similar calculations carried out on helium-3 were not satisfactory. In this investigation, a new electromagnetic form factor of helium-3 is measured. The transfer zone of the diffraction spectra concerning the first minimum and the second maximum is considered. The aim of the study is to test on both nuclei the validity and the uncertainties of the models. The scattering of electrons on helium-3 is analyzed. The experiment was performed in the Saclay linear accelerator. The isoscalar and isovector form factors could be differentiated. By comparing the theoretical and the experimental data, it is demonstrated that the use of three body forces in the calculations has no effect on the form factor results [fr
The proton electromagnetic form factor F2 and quark orbital angular ...
Protein; electromagnetic form factors; perturbative QCD; quark orbital angular momentum. ... Failures of the ASD approach to correctly predict ex- perimental ... The success of the formalism is the correct prediction of the Q2 scaling behavior of ...
The three-loop form factor in N=4 super Yang-Mills theory
Gehrmann, Thomas [Universitaet Zuerich (Switzerland); Henn, Johannes [IAS Princeton (United States); Huber, Tobias [Universitaet Siegen (Germany)
2012-07-01
We present the calculation of the Sudakov form factor in N=4 super Yang-Mills theory to the three-loop order. At leading colour, the latter is expressed in terms of planar and non-planar loop integrals. We show that it is possible to choose a representation in which each loop integral has uniform transcendentality in the Riemann {zeta}-function. We comment on the expected exponentiation of the infrared divergences and the values of the three-loop cusp and collinear anomalous dimensions in dimensional regularisation. We also compare the form factor in N=4 super Yang-Mills to the leading transcendentality pieces of the quark and gluon form factor in QCD. Finally, we investigate the ultraviolet properties of the form factor in D>4 dimensions.
Inelastic magnetic electron scattering form factors of the 26 Mg nucleus
Magnetic electron scattering (3) form factors with core polarization effects, ... to 3+ states of the 26Mg nucleus have been studied using shell model calculations. ... The wave functions of the radial single-particle matrix elements have been ...
Constraints on the [Formula: see text] form factor from analyticity and unitarity.
Ananthanarayan, B; Caprini, I; Kubis, B
Motivated by the discrepancies noted recently between the theoretical calculations of the electromagnetic [Formula: see text] form factor and certain experimental data, we investigate this form factor using analyticity and unitarity in a framework known as the method of unitarity bounds. We use a QCD correlator computed on the spacelike axis by operator product expansion and perturbative QCD as input, and exploit unitarity and the positivity of its spectral function, including the two-pion contribution that can be reliably calculated using high-precision data on the pion form factor. From this information, we derive upper and lower bounds on the modulus of the [Formula: see text] form factor in the elastic region. The results provide a significant check on those obtained with standard dispersion relations, confirming the existence of a disagreement with experimental data in the region around [Formula: see text].
Virtual photons in the pion form factors and the energy-momentum tensor
Kubis, Bastian E-mail: b.kubis@fz-juelich.de; Meissner, Ulf-G. E-mail: ulf-g.meissner@fz-juelich.de
2000-05-22
We evaluate the vector and scalar form factor of the pion in the presence of virtual photons at next-to-leading order in two-flavor chiral perturbation theory. We also consider the scalar and tensor pion form factors of the energy-momentum tensor. We find that the intrinsic electromagnetic corrections are very small for the vector as well as the charged pion scalar form factor. The scalar radius of the neutral pion is reduced by two percent. We perform infrared regularization by considering electron-positron annihilation into pions and the decay of a light Higgs boson into a pion pair. We discuss the detector resolution dependent contributions to the various form factors and pion radii.
Constraints on the ωπ form factor from analyticity and unitarity
Ananthanarayan, B.; Caprini, I.; Kubis, B.
2014-01-01
Motivated by the discrepancies noted recently between the theoretical calculations of the electromagnetic ωπ form factor and certain experimental data, we investigate this form factor using analyticity and unitarity in a framework known as the method of unitarity bounds. We use a QCD correlator computed on the spacelike axis by operator product expansion and perturbative QCD as input, and exploit unitarity and the positivity of its spectral function, including the two-pion contribution that can be reliably calculated using high-precision data on the pion form factor. From this information, we derive upper and lower bounds on the modulus of the ωπ form factor in the elastic region. The results provide a significant check on those obtained with standard dispersion relations, confirming the existence of a disagreement with experimental data in the region around 0.6 GeV. (orig.)
Virtual photons in the pion form factors and the energy-momentum tensor
Kubis, Bastian; Meissner, Ulf-G.
2000-01-01
We evaluate the vector and scalar form factor of the pion in the presence of virtual photons at next-to-leading order in two-flavor chiral perturbation theory. We also consider the scalar and tensor pion form factors of the energy-momentum tensor. We find that the intrinsic electromagnetic corrections are very small for the vector as well as the charged pion scalar form factor. The scalar radius of the neutral pion is reduced by two percent. We perform infrared regularization by considering electron-positron annihilation into pions and the decay of a light Higgs boson into a pion pair. We discuss the detector resolution dependent contributions to the various form factors and pion radii
Constraints on the ωπ form factor from analyticity and unitarity
Ananthanarayan, B. [Indian Institute of Science, Centre for High Energy Physics, Bangalore (India); Caprini, I. [Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O.B. MG-6, Magurele (Romania); Kubis, B. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen-und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Bonn (Germany)
2014-12-01
Motivated by the discrepancies noted recently between the theoretical calculations of the electromagnetic ωπ form factor and certain experimental data, we investigate this form factor using analyticity and unitarity in a framework known as the method of unitarity bounds. We use a QCD correlator computed on the spacelike axis by operator product expansion and perturbative QCD as input, and exploit unitarity and the positivity of its spectral function, including the two-pion contribution that can be reliably calculated using high-precision data on the pion form factor. From this information, we derive upper and lower bounds on the modulus of the ωπ form factor in the elastic region. The results provide a significant check on those obtained with standard dispersion relations, confirming the existence of a disagreement with experimental data in the region around 0.6 GeV. (orig.)
Model for next-to-leading order threshold resummed form factors
Aglietti, Ugo; Ricciardi, Giulia
2004-01-01
We present a model for next-to-leading order resummed threshold form factors based on a timelike coupling recently introduced in the framework of small x physics. Improved expressions for the form factors in N-space are obtained which are not plagued by Landau-pole singularities, as the included absorptive effects - usually neglected - act as regulators. The physical reason is that, because of faster decay of gluon jets, there is not enough resolution time to observe the Landau pole. Our form factors reduce to the standard ones when the absorptive parts related to the coupling are neglected. The inverse transform from N-space to x-space can be done directly without any prescription and we obtain analytical expressions for the form factors, which are well defined in all x-space
Electric form factors of the octet baryons from lattice QCD and chiral extrapolation
Shanahan, P.E.; Thomas, A.W.; Young, R.D.; Zanotti, J.M.; Pleiter, D.; Stueben, H.
2014-03-01
We apply a formalism inspired by heavy baryon chiral perturbation theory with finite-range regularization to dynamical 2+1-flavor CSSM/QCDSF/UKQCD Collaboration lattice QCD simulation results for the electric form factors of the octet baryons. The electric form factor of each octet baryon is extrapolated to the physical pseudoscalar masses, after finite-volume corrections have been applied, at six fixed values of Q 2 in the range 0.2-1.3 GeV 2 . The extrapolated lattice results accurately reproduce the experimental form factors of the nucleon at the physical point, indicating that omitted disconnected quark loop contributions are small. Furthermore, using the results of a recent lattice study of the magnetic form factors, we determine the ratio μ p G E p /G M p . This quantity decreases with Q 2 in a way qualitatively consistent with recent experimental results.
Effects of Velocity-Dependent Force on the Magnetic Form Factors of Odd-Z Nuclei
Tie-Kuang, Dong; Zhong-Zhou, Ren
2008-01-01
We investigate the effects of the velocity-dependent force on the magnetic form factors and magnetic moments of odd-Z nuclei. The form factors are calculated with the harmonic-oscillator wavefunctions. It is found that the contributions of the velocity-dependent force manifest themselves in the very large momentum transfer region (q ≥ 4fm- 1 ). In the low and medium q region the contributions of the velocity-dependent force are very small compared with those without this force. However, in the high-q region the contributions of the velocity-dependent force are larger than the normal form factors. The diffraction structures beyond the existing experimental data are found after the contributions of the velocity-dependent force are included. The formula of the correction to the single particle magnetic moment due to the velocity-dependent force is reproduced exactly in the long-wavelength limit (q = 0) of the M1 form factor
Asymptotic dynamics of QCD, coherent states and the quark form factor
Steiner, F.; Dahmen, H.D.
1980-05-01
The method of asymptotic dynamics for large times developed by Kulish and Fadde'ev for QED is applied to QCD. We study the solution and calculate the on shell quark form factor in leading logarithmic order. (orig.)
Extrapolation of π-meson form factor, zeros in the analyticity domain
Morozov, P.T.
1978-01-01
The problem of a stable extrapolation from the cut to an arbitrary interior of the analyticity domain for the pion form factor is formulated and solved. As it is shown a stable solution can be derived if module representations with the Karleman weight function are used as the analyticity conditions. The case when the form factor has zeros is discussed. If there are zeros in the complex plane they must be taken into account when determining the extrapolation function
Measurement of the energy dependence of the form factor $f_{+}$ in $K^{0}_{e3}$ decay
Apostolakis, Alcibiades J; Backenstoss, Gerhard; Bargassa, P; Behnke, O; Benelli, A; Bertin, V; Blanc, F; Bloch, P; Carlson, P J; Carroll, M; Cawley, E; Chertok, M B; Danielsson, M; Dejardin, M; Derré, J; Ealet, A; Eleftheriadis, C; Fetscher, W; Fidecaro, Maria; Filipcic, A; Francis, D; Fry, J; Gabathuler, Erwin; Gamet, R; Gerber, H J; Go, A; Haselden, A; Hayman, P J; Henry-Coüannier, F; Hollander, R W; Jon-And, K; Kettle, P R; Kokkas, P; Kreuger, R; Le Gac, R; Leimgruber, F; Mandic, I; Manthos, N; Marel, Gérard; Mikuz, M; Miller, J; Montanet, François; Müller, A; Nakada, Tatsuya; Pagels, B; Papadopoulos, I M; Pavlopoulos, P; Polivka, G; Rickenbach, R; Roberts, B L; Ruf, T; Schäfer, M; Schaller, L A; Schietinger, T; Schopper, A; Tauscher, Ludwig; Thibault, C; Touchard, F; Touramanis, C; van Eijk, C W E; Vlachos, S; Weber, P; Wigger, O; Wolter, M; Zavrtanik, D; Zimmerman, D
2000-01-01
Neutral-kaon decays to \\pielnu\\ % recorded by the CPLEAR experimentwere analysed to determine the $q^2$ dependence of the \\Kzet\\ electroweak form factor $f_+$. Based on $365\\,612$ events,this form factor was found to have a linear dependence on $q^2$with a slope $\\lambda_+ = 0.0245 \\pm 0.0012_{\\text{stat}} \\pm 0.0022_{\\text{syst}}$.
The spin-dependent neutralino-nucleus form factor for 127I
Ressell, M.T.
1996-01-01
We present the results of detailed shell model calculations of the spin-dependent elastic form factor for the nucleus 127 I. the calculations were performed in extremely large model spaces which adequately describe the configuration mixing in this nucleus. Good agreement between the calculated and experimental values of the magnetic moment are found. Other nuclear observables are also compared to experiment. The dependence of the form factor upon the model space and effective interaction is discussed
Relativistic two-fermion equations with form factors and anomalous magnetic moment interactions
Ahmed, S.
1977-04-01
Relativistic equations for two-fermion systems are derived from quantum field theory taking into account the form factors of the particles. When the q 2 dependence of the form factors is disregarded, in the static approximation, the two-fermion equations with Coulomb and anomalous magnetic moment interactions are obtained. Separating the angular variables, a sixteen-component relativistic radial equation are finally given
Meson form factors and covariant three-dimensional formulation of the composite model
Skachkov, N.B.; Solovtsov, I.L.
1979-01-01
An apparatus is developed which allows within the relativistic quark model, to find explicit expressions for meson form factors in terms of the wave functions of two-quark system that obey the covariant two-particle quasipotential equation. The exact form of wave functions is obtained by passing to the relativistic configurational representation. As an example, the quark Coulomb interaction is considered
Cutting through form factors and cross sections of non-protected operators in N=4 SYM
Nandan, Dhritiman; Sieg, Christoph; Wilhelm, Matthias; Yang, Gang
2015-01-01
We study the form factors of the Konishi operator, the prime example of non-protected operators in N=4 SYM theory, via the on-shell unitarity method. Since the Konishi operator is not protected by supersymmetry, its form factors share many features with amplitudes in QCD, such as the occurrence of rational terms and of UV divergences that require renormalization. A subtle point is that this operator depends on the spacetime dimension. This requires a modification when calculating its form factors via the on-shell unitarity method. We derive a rigorous prescription that implements this modification to all loop orders and obtain the two-point form factor up to two-loop order and the three-point form factor to one-loop order. From these form factors, we construct an IR-finite cross-section-type quantity, namely the inclusive decay rate of the (off-shell) Konishi operator to any final (on-shell) state. Via the optical theorem, it is connected to the imaginary part of the two-point correlation function. We extract the Konishi anomalous dimension up to two-loop order from it.
Charged Hadron Properties in Background Electric Fields
Detmold, William; Tiburzi, Brian C.; Walker-Loud, Andre
2010-01-01
We report on a lattice calculation demonstrating a novel new method to extract the electric polarizability of charged pseudo-scalar mesons by analyzing two point correlation functions computed in classical background electric fields. A staple component of any electrodynamics or quantum mechanics course is the electric polarizability. Neutral material immersed in a weak external field polarizes, internally setting up an electric dipole moment, aligned so as to minimize the energy. At the atomic level, the electron clouds are distorted creating these microscopic dipole moments. The same process occurs at the hadronic level but the polarization effects are now constrained by the strong force. Polarizabilities of these bound QCD states can be viewed as a distortion of the charged pion cloud of a given hadron. One can use lattice QCD to non-perturbatively compute the quark and gluon interactions in the presence of background electric (or magnetic) fields. For sufficiently weak background fields, the low energy properties of the hadrons can be rigorously computed using effective field theory. With this treatment, a picture of hadrons emerges from chiral dynamics: that of a hadronic core surrounded by a pseudoscalar meson cloud. As some pseudoscalar mesons are charged, polarizabilities of hadrons encode the stiffness of the charged meson cloud (as well as that of the core). The form of pseudoscalar meson polarizabilities is consequently strongly constrained by chiral dynamics. However, beyond the leading order, the results depend upon essentially unknown low-energy constants, which must currently be estimated in a model-dependent fashion. In the case of the charged pion, the experimental measurement of the polarizability has proven difficult, both in the original measurement as well as the most recent published result. Currently, there is a 2-3 sigma discrepancy between the two-loop cPT prediction and the measured charged pion polarizability. New results with higher
Klein, Christoph
2011-09-23
Transitions of charmed hadrons are of significant importance, since they provide possibilities to extract the CKM matrix elements V{sub cd} and V{sub cs} from experimental data as well as interesting channels to search for new physics effects. However, quarks are bound in hadrons, and it is necessary to describe this effect in a reliable way, to study the underlying flavour dynamics. For this, one has to use nonperturbative tools, to determine the corresponding transition amplitudes. The results of such calculations can furthermore be of use, to test the predictions of QCD and to contribute to a deeper understanding of the structure of hadrons. In this thesis two topics are investigated using the method of QCD light-cone sum rules (LCSRs). The first topic consists in the form factors of the semileptonic decays D {yields} {pi}l{nu}{sub l} and D {yields} Kl{nu}{sub l}, for which new results are calculated using up-to-date input values. Since LCSRs are not applicable in the whole range of kinematics, they are extrapolated by the use of appropriate parametrisations and the results agree well with experimental data. The second topic are the transitions of charmed baryons to a nucleon. Here the corresponding transition form factors and in addition the hadronic {lambda}{sub c}D{sup (*)}N and {sigma}{sub c}D{sup (*)}N coupling constants are calculated - the latter by the consideration of double dispersion relations. These coupling constants are of special interest for the description of hadronic interactions, like open charm production in proton-antiprotoncollisions. Furthermore there appears the problem, that both parity states of a baryon contribute to the considered functional representation, for which a consistent way to separate them is presented. (orig.)
Novel Perspectives for Hadron Physics
Brodsky, Stanley
2012-01-01
I discuss several novel and unexpected aspects of quantum chromodynamics. These include: (a) the nonperturbative origin of intrinsic strange, charm and bottom quarks in the nucleon at large x; the breakdown of pQCD factorization theorems due to the lensing effects of initial- and final-state interactions; (b) important corrections to pQCD scaling for inclusive reactions due to processes in which hadrons are created at high transverse momentum directly in the hard processes and their relation to the baryon anomaly in high-centrality heavy-ion collisions; and (c) the nonuniversality of quark distributions in nuclei. I also discuss some novel theoretical perspectives in QCD: (a) light-front holography - a relativistic color-confining first approximation to QCD based on the AdS/CFT correspondence principle; (b) the principle of maximum conformality - a method which determines the renormalization scale at finite order in perturbation theory yielding scheme independent results; (c) the replacement of quark and gluon vacuum condensates by 'in-hadron condensates' and how this helps to resolve the conflict between QCD vacuum and the cosmological constant.
Novel Perspectives for Hadron Physics
Brodsky, Stanley J.; /SLAC
2012-03-09
I discuss several novel and unexpected aspects of quantum chromodynamics. These include: (a) the nonperturbative origin of intrinsic strange, charm and bottom quarks in the nucleon at large x; the breakdown of pQCD factorization theorems due to the lensing effects of initial- and final-state interactions; (b) important corrections to pQCD scaling for inclusive reactions due to processes in which hadrons are created at high transverse momentum directly in the hard processes and their relation to the baryon anomaly in high-centrality heavy-ion collisions; and (c) the nonuniversality of quark distributions in nuclei. I also discuss some novel theoretical perspectives in QCD: (a) light-front holography - a relativistic color-confining first approximation to QCD based on the AdS/CFT correspondence principle; (b) the principle of maximum conformality - a method which determines the renormalization scale at finite order in perturbation theory yielding scheme independent results; (c) the replacement of quark and gluon vacuum condensates by 'in-hadron condensates' and how this helps to resolve the conflict between QCD vacuum and the cosmological constant.
High energy approximations for nuclear knockout form factors at small momentum transfer
Amado, R.D.; Cannata, F.; Dedonder, J.P.
1985-01-01
We obtain an explicit approximate expression for the nucleon knockout form factor at small momentum transfer induced by a scalar probe in a single particle model in terms of the momentum space bound state wave function. Our form preserves the orthogonality constraint without using explicitly the final state scattering wave function. We examine the leading large momentum behavior of the momentum space wave function and of correction terms to our expression for the form factor in the case where the bound state is an s state
Single-Spin Polarization Effects and the Determination of Timelike Proton Form Factors
Brodsky, S
2003-10-24
We show that measurements of the proton's polarization in e{sup +}e{sup -} {yields} p{bar p} strongly discriminate between analytic forms of models which fit the proton form factors in the spacelike region. In particular, the single-spin asymmetry normal to the scattering plane measures the relative phase difference between the timelike G{sub E} and G{sub M} form factors. The expected proton polarization in the timelike region is large, of order of several tens of percent.
Cui, Lixia; Lin, Wenwen; Oei, Tian P. S.
2011-01-01
This study investigated cross-cultural differences in the factor structure and psychometric properties of the Young Schema Questionnaire (short form; YSQ-SF). The participants were 712 Chinese undergraduate students. The total sample was randomly divided into two sub-samples. Exploratory Factor Analysis (EFA) was conducted on questionnaire results…
Spontaneous magnetization of quantum XY-chain from finite chain form-factor
Iorgov, N.Z.
2010-01-01
Using the explicit factorized formulas for matrix elements (form-factors) of the spin operators between vectors of the Hamiltonian of a finite quantum XY-chain in a transverse field, the spontaneous magnetization for σ x and σ y is re-derived in a simple way.
Multilevel Confirmatory Factor Analysis of the Teacher My Class Inventory-Short Form
Villares, Elizabeth; Mariani, Melissa; Sink, Christopher A.; Colvin, Kimberly
2016-01-01
Researchers analyzed data from elementary teachers (N = 233) to further establish the psychometric soundness of the Teacher My Class Inventory-Short Form. Supporting previous psychometric research, confirmatory factor analyses findings supported the factorial validity of the hypothesized five-factor solution. Internal reliability estimates were…
Electromagnetic and axial-vector form factors of the quarks and nucleon
Dahiya, Harleen; Randhawa, Monika
2017-11-01
In light of the improved precision of the experimental measurements and enormous theoretical progress, the nucleon form factors have been evaluated with an aim to understand how the static properties and dynamical behavior of nucleons emerge from the theory of strong interactions between quarks. We have analyzed the vector and axial-vector nucleon form factors (GE,Mp,n(Q2) and GAp,n(Q2)) using the spin observables in the chiral constituent quark model (χCQM) which has made a significant contribution to the unraveling of the internal structure of the nucleon in the nonperturbative regime. We have also presented a comprehensive analysis of the flavor decomposition of the form factors (GEq(Q2), GMq(Q2) and GAq(Q2) for q = u,d,s) within the framework of χCQM with emphasis on the extraction of the strangeness form factors which are fundamental to determine the spin structure and test the chiral symmetry breaking effects in the nucleon. The Q2 dependence of the vector and axial-vector form factors of the nucleon has been studied using the conventional dipole form of parametrization. The results are in agreement with the available experimental data.
Charge form factors and alpha-cluster internal structure of 12C
Luk'yanov, V.K.; Zemlyanaya, E.V.; Kadrev, D.N.; Antonov, A.N.; Spasova, K.; Anagnostatos, G.S.; Ginis, P.; Giapitzakis, J.
1999-01-01
The transition densities and form factors of 0 + , 2 + , and 3 - states in 12 C are calculated in alpha-cluster model using the triangle frame with clusters in the vertices. The wave functions of nucleons in the alpha clusters are taken as they were obtained in the framework of the models used for the description of the 4 He form factor and momentum distribution which are based on the one-body density matrix construction. They contain effects of the short-range NN correlations, as well as the d-shell admixtures in 4 He. Calculations and the comparison with the experimental data show that visible effects on the form and magnitude of the 12 C form factors take place, especially at relatively large momentum transfers
Lavender, Gemma
2018-01-01
What is the universe made of? How did it start? This Manual tells the story of how physicists are seeking answers to these questions using the worlds largest particle smasher the Large Hadron Collider at the CERN laboratory on the Franco-Swiss border. Beginning with the first tentative steps taken to build the machine, the digestible text, supported by color photographs of the hardware involved, along with annotated schematic diagrams of the physics experiments, covers the particle accelerators greatest discoveries from both the perspective of the writer and the scientists who work there. The Large Hadron Collider Manual is a full, comprehensive guide to the most famous, record-breaking physics experiment in the world, which continues to capture the public imagination as it provides new insight into the fundamental laws of nature.
Yamazaki, Toshimitsu
1990-01-01
The Japanese Hadron Project (JHP) is aimed at producing various kinds of unstable secondary beams based on high-intensity protons from a new accelerator complex. The 1 GeV protons, first produced from a 1 GeV linac, are transferred to a compressor/stretcher ring, where a sharply-pulsed beam or a stretched continuous beam will be produced. The pulsed beam will be used for a pulsed muon source (M arena) and a spallation neutron source (N arena). A part of the proton beam will be used to produce unstable nuclei, which will be accelerated to several MeV/nucleon (E arena). The purpose and impact of JHP will be described in view of future applications of hadronic beams to nuclear energy and material science. (author)
Roser, T.
1994-01-01
There were four sessions on Hadron Beams and Accelerators with 7 talks on Siberian Snakes and spin rotators, 3 talks on polarization build-up of unpolarized beams in storage rings and 5. 9, and 3 talks on low, medium, and high energy polarimeters, respectively. In this paper I will briefly describe a few highlights from these sessions, giving emphasis to topics which I think will play an important role in the future
Roser, T.
1995-01-01
There were four sessions on Hadron Beams and Accelerators with 7 talks on Siberian Snakes and spin rotators, 3 talks on polarization build-up of unpolarized beams in storage rings and 5, 9, and 3 talks on low, medium, and high energy polarimeters, respectively. In this paper I will briefly describe a few highlights from these sessions, giving emphasis to topics which I think will play an important role in the future. copyright 1995 American Institute of Physics
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
Electromagnetic polarizabilities of hadrons
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
Massen, S. E.; Garistov, V. P.; Grypeos, M. E.
1996-01-01
The effects of nuclear surface fluctuations on harmonic oscillator elastic charge form factor of light nuclei are investigated, simultaneously approximating the short-range correlations through a Jastrow correlation factor. Inclusion of the surface fluctuation effects within this description, by truncating the cluster expansion at the two-body part, is found to improve somewhat the fit to the elastic charge form-factor of 16 O and 40 Ca. However, the convergence of the cluster expansion is expected to deteriorate. An additional finding is that surface-fluctuation correlations produce a drastic change in the asymptotic behaviour of the point-proton form-factor, which now falls off quite slowly (i.e. as const.q -4 ) at large values of the momentum transfer q
The NE11 experiment at SLAC and the neutron form factors
Stuart, L.M.; Lung, A.; Bosted, P.E.
1993-05-01
The neutron electromagnetic form factors G En and G Mn , which reflect the charge and magnetization distributions within the neutron, are of fundamental importance for understanding nucleon structure, and are necessary for calculations of processes involving the electromagnetic interaction with complex nuclei. These quantities are functions of Q 2 , the four-momentum transfer squared. SLAC experiment NE11 has measured these form factors out to a Q 2 of 4.0 (GeV/c) 2 with high precision, and the results have been recently published. This paper provides some additional details on the extraction of G Mn and G En from the NE11 measurements. Several formalisms have been developed over the years which attempt to understand the nucleon form factors using basic physical principles. Vector Meson Dominance (VMD) models are based on superpositions of photon couplings to various vector mesons. These models generally involve free parameters which are fit to form factor data at low Q 2 , and are not expected to be valid at high Q 2 . For asymptotically large Q 2 , dimensional scaling methods and perturbative Quantum Chromodynamics (pQCD) predict form factor behavior at large Q 2 , but they do not make absolute magnitude predictions. To describe the form factor behavior at intermediate values of Q 2 , a hybrid model by Gari and Kruempelmann (GK) uses VMD constraints at low Q 2 and pQCD constraints at high Q 2 . Free parameters in the model are adjusted to fit existing form factor data. Other approaches include the use of QCD sum rules to make absolute predictions, diquark models, and relativistic constituent quark models
Sulkosky, V.; Jin, G.; Long, E.; Zhang, Y.-W.; Mihovilovic, M.; Kelleher, A.; Anderson, B.; Higinbotham, D. W.; Širca, S.; Allada, K.; Annand, J. R. M.; Averett, T.; Bertozzi, W.; Boeglin, W.; Bradshaw, P.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, C.; Chen, J.-P.; Chudakov, E.; De Leo, R.; Deng, X.; Deur, A.; Dutta, C.; El Fassi, L.; Flay, D.; Frullani, S.; Garibaldi, F.; Gao, H.; Gilad, S.; Gilman, R.; Glamazdin, O.; Golge, S.; Gomez, J.; Hansen, J.-O.; Holmstrom, T.; Huang, J.; Ibrahim, H.; de Jager, C. W.; Jensen, E.; Jiang, X.; Jones, M.; Kang, H.; Katich, J.; Khanal, H. P.; King, P.; Korsch, W.; LeRose, J.; Lindgren, R.; Lu, H.-J.; Luo, W.; Markowitz, P.; Meekins, D.; Meziane, M.; Michaels, R.; Moffit, B.; Monaghan, P.; Muangma, N.; Nanda, S.; Norum, B. E.; Pan, K.; Parno, D.; Piasetzky, E.; Posik, M.; Punjabi, V.; Puckett, A. J. R.; Qian, X.; Qiang, Y.; Qui, X.; Riordan, S.; Saha, A.; Sawatzky, B.; Shabestari, M.; Shahinyan, A.; Shoenrock, B.; John, J. St.; Subedi, R.; Tobias, W. A.; Tireman, W.; Urciuoli, G. M.; Wang, D.; Wang, K.; Wang, Y.; Watson, J.; Wojtsekhowski, B.; Ye, Z.; Zhan, X.; Zhang, Y.; Zheng, X.; Zhao, B.; Zhu, L.; Jefferson Lab Hall A Collaboration
2017-12-01
Background: Measurements of the neutron charge form factor, GEn, are challenging because the neutron has no net charge. In addition, measurements of the neutron form factors must use nuclear targets which require accurately accounting for nuclear effects. Extracting GEn with different targets and techniques provides an important test of our handling of these effects. Purpose: The goal of the measurement was to use an inclusive asymmetry measurement technique to extract the neutron charge form factor at a four-momentum transfer of 1 (GeV/c ) 2 . This technique has very different systematic uncertainties than traditional exclusive measurements and thus serves as an independent check of whether nuclear effects have been taken into account correctly. Method: The inclusive quasielastic reaction 3He ⃗(e ⃗,e') was measured at Jefferson Laboratory. The neutron electric form factor, GEn, was extracted at Q2=0.98 (GeV/c ) 2 from ratios of electron-polarization asymmetries measured for two orthogonal target spin orientations. This Q2 is high enough that the sensitivity to GEn is not overwhelmed by the neutron magnetic contribution, and yet low enough that explicit neutron detection is not required to suppress pion production. Results: The neutron electric form factor, GEn, was determined to be 0.0414 ±0.0077 (stat)±0.0022 (syst) , providing the first high-precision inclusive extraction of the neutron's charge form factor. Conclusions: The use of the inclusive quasielastic 3He ⃗(e ⃗,e') with a four-momentum transfer near 1 (GeV/c ) 2 has been used to provide a unique measurement of GEn. This new result provides a systematically independent validation of the exclusive extraction technique results and implies that the nuclear corrections are understood. This is contrary to the proton form factor where asymmetry and differential cross section measurements have been shown to have large systematic differences.
Brodsky, Stanley J.; Deshpande, Abhay L.; Gao, Haiyan; McKeown, Robert D.; Meyer, Curtis A.; Meziani, Zein-Eddine; Milner, Richard G.; Qiu, Jianwei; Richards, David G.; Roberts, Craig D.
2015-02-26
This White Paper presents the recommendations and scientific conclusions from the Town Meeting on QCD and Hadronic Physics that took place in the period 13-15 September 2014 at Temple University as part of the NSAC 2014 Long Range Planning process. The meeting was held in coordination with the Town Meeting on Phases of QCD and included a full day of joint plenary sessions of the two meetings. The goals of the meeting were to report and highlight progress in hadron physics in the seven years since the 2007 Long Range Plan (LRP07), and present a vision for the future by identifying the key questions and plausible paths to solutions which should define the next decade. The introductory summary details the recommendations and their supporting rationales, as determined at the Town Meeting on QCD and Hadron Physics, and the endorsements that were voted upon. The larger document is organized as follows. Section 2 highlights major progress since the 2007 LRP. It is followed, in Section 3, by a brief overview of the physics program planned for the immediate future. Finally, Section 4 provides an overview of the physics motivations and goals associated with the next QCD frontier: the Electron-Ion-Collider.
Keil, Eberhard
1998-01-01
Plans for future hadron colliders are presented, and accelerator physics and engineering aspects common to these machines are discussed. The Tevatron is presented first, starting with a summary of the achievements in Run IB which finished in 1995, followed by performance predictions for Run II which will start in 1999, and the TeV33 project, aiming for a peak luminosity $L ~ 1 (nbs)^-1$. The next machine is the Large Hadron Collider LHC at CERN, planned to come into operation in 2005. The last set of machines are Very Large Hadron Colliders which might be constructed after the LHC. Three variants are presented: Two machines with a beam energy of 50 TeV, and dipole fields of 1.8 and 12.6 T in the arcs, and a machine with 100 TeV and 12 T. The discussion of accelerator physics aspects includes the beam-beam effect, bunch spacing and parasitic collisions, and the crossing angle. The discussion of the engineering aspects covers synchrotron radiation and stored energy in the beams, the power in the debris of the p...
Hadronization, spin and lifetimes
Grossman, Yuval; Nachshon, Itay
2008-01-01
Measurements of lifetimes can be done in two ways. For very short lived particles, the width can be measured. For long lived ones, the lifetime can be directly measured, for example, using a displaced vertex. Practically, the lifetime cannot be extracted for particles with intermediate lifetimes. We show that for such cases information about the lifetime can be extracted for heavy colored particles that can be produced with known polarization. For example, a t-like particle with intermediate lifetime hadronizes into a superposition of the lowest two hadronic states, T* and T (the equivalent of B* and B). Depolarization effects are governed by time scales that are much longer than the hadronization time scale, Λ QCD -1 . After a time of order 1/Δm, with Δm≡m(T*)-m(T), half of the initial polarization is lost. The polarization is totally lost after a time of order 1/Γ γ , with Γ γ = Γ(T* → Tγ). Thus, by comparing the initial and final polarization, we get information on the particle's lifetime.
Supersymmetry at hadron supercolliders
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
Experimental study of inclusive single hadron production by neutrinos
Scott, W.G.
1979-01-01
A study of inclusive single hadron production by neutrinos performed as part of an experiment studying neutrino proton interactions using BEBC filled with hydrogen is reported. Emphasis is given to questions related to factorization and scaling deviations in fragmentation functions
The role of hadron resonances in hot hadronic matter
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.
Data on the electromagnetic pion form factor and p-wave
Dubnicka, S.; Meshcheryakov, V.A.; Milko, J.
1980-01-01
The pion form factor absolute value data (free of the omega meson contribution) are unified with the P-wave isovector ππ phase shift. The resultant real and imaginary parts of the pion form factor are described by means of the Pade approximation. All the data, which involve the pion form factor experimental points from the range of momenta - 0.8432 GeV 2 2 , the pion charge radius, and the P-wave isovector ππ phase shift in the elastic region (including also the generally accepted value of the scattering length) are mutually consistent. The data themselves through the Pade approximation reveal that the aforementioned consistency can be achieved only if the pion form factor left-hand cut from the second Riemann sheet is taken into account. Almost in all of the considered Pade approximations one stable pion form factor zero is found in the space-like region, which might indicate the existence of a diffraction minimum in the differential cross section for elastic e - π scattering as a consequence of the constituent structure of the pion like in the case of the electron elastic scattering on nuclei
How well do we know the electromagnetic form factors of the proton?
Arrington, J.
2003-01-01
Several experiments have extracted proton electromagnetic form factors from elastic cross section measurements using the Rosenbluth technique. Global analyses of these measurements indicate approximate scaling of the electric and magnetic form factors (μ p G E p /G M p ≅1), in contrast to recent polarization transfer measurements from Jefferson Lab. We present here a global reanalysis of the cross section data aimed at understanding the disagreement between the Rosenbluth extraction and the polarization transfer data. We find that the individual cross section measurements are self-consistent, and that the new global analysis yields results that are still inconsistent with polarization measurements. This discrepancy indicates a fundamental problem in one of the two techniques, or a significant error in polarization transfer or cross section measurements. An error in the polarization data would imply a large error in the extracted electric form factor, while an error in the cross sections implies an uncertainty in the extracted form factors, even if the form factor ratio is measured exactly
Hadronic structure of the weak neutral current
Marriner, J.P.
1977-01-01
A comparison of neutral and charged current deep inelastic neutrino interactions is made in an experiment utilizing the Fermilab 15 ft. bubble chamber. The ratio of neutral current events (NC) to charged current events (CC) is 0.35 +- 0.06 when the visible hadronic energy is greater than 10 GeV. The distributions of NC and CC in a new variable called u/sub vis/, which depends only on the observed hadrons, are given. From these distributions and the assumption that the x distribution is the same for NC and CC, it is concluded that for a NC y distribution of the form (1 - eta) + 3 eta(1 - y) 2 , eta = .12 +- .32. The ratio rho/sub NC/(rho/sub CC/) of neutron to proton cross sections in NC(CC) is studied and the quotient rho/sub NC//rho/sub CC/ = 0.7 +- 0.2. The distribution of hadrons in z/sub vis/, the scaled hadronic momentum, is given. The CC hadrons fit the predictions of the quark fragmentation functions D/sub u//sup π + /(z) and D/sub u//sup π - /(z) as given by Field and Feynman. The neutral current events fit the form (1 - lambda)D/sub u//sup π + /(z) + lambda D/sub d//sup π + /(z) for positives and (1 - lambda)D/sub u//sup π - /(z) + lambda D/sub d//sup π - /(z) for negatives with lambda = 0.56 +- 0.10 and a fit confidence level of 4%
Feasibility studies of time-like proton electromagnetic form factors at overlinePANDA at FAIR
Singh, B.; Erni, W.; Krusche, B.; Steinacher, M.; Walford, N.; Liu, B.; Liu, H.; Liu, Z.; Shen, X.; Wang, C.; Zhao, J.; Albrecht, M.; Erlen, T.; Fink, M.; Heinsius, F.; Held, T.; Holtmann, T.; Jasper, S.; Keshk, I.; Koch, H.; Kopf, B.; Kuhlmann, M.; Kümmel, M.; Leiber, S.; Mikirtychyants, M.; Musiol, P.; Mustafa, A.; Pelizäus, M.; Pychy, J.; Richter, M.; Schnier, C.; Schröder, T.; Sowa, C.; Steinke, M.; Triffterer, T.; Wiedner, U.; Ball, M.; Beck, R.; Hammann, C.; Ketzer, B.; Kube, M.; Mahlberg, P.; Rossbach, M.; Schmidt, C.; Schmitz, R.; Thoma, U.; Urban, M.; Walther, D.; Wendel, C.; Wilson, A.; Bianconi, A.; Bragadireanu, M.; Caprini, M.; Pantea, D.; Patel, B.; Czyzycki, W.; Domagala, M.; Filo, G.; Jaworowski, J.; Krawczyk, M.; Lisowski, F.; Lisowski, E.; Michałek, M.; Poznański, P.; Płażek, J.; Korcyl, K.; Kozela, A.; Kulessa, P.; Lebiedowicz, P.; Pysz, K.; Schäfer, W.; Szczurek, A.; Fiutowski, T.; Idzik, M.; Mindur, B.; Przyborowski, D.; Swientek, K.; Biernat, J.; Kamys, B.; Kistryn, S.; Korcyl, G.; Krzemien, W.; Magiera, A.; Moskal, P.; Pyszniak, A.; Rudy, Z.; Salabura, P.; Smyrski, J.; Strzempek, P.; Wronska, A.; Augustin, I.; Böhm, R.; Lehmann, I.; Nicmorus Marinescu, D.; Schmitt, L.; Varentsov, V.; Al-Turany, M.; Belias, A.; Deppe, H.; Dzhygadlo, R.; Ehret, A.; Flemming, H.; Gerhardt, A.; Götzen, K.; Gromliuk, A.; Gruber, L.; Karabowicz, R.; Kliemt, R.; Krebs, M.; Kurilla, U.; Lehmann, D.; Löchner, S.; Lühning, J.; Lynen, U.; Orth, H.; Patsyuk, M.; Peters, K.; Saito, T.; Schepers, G.; Schmidt, C. J.; Schwarz, C.; Schwiening, J.; Täschner, A.; Traxler, M.; Ugur, C.; Voss, B.; Wieczorek, P.; Wilms, A.; Zühlsdorf, M.; Abazov, V.; Alexeev, G.; Arefiev, V. A.; Astakhov, V.; Barabanov, M. Yu.; Batyunya, B. V.; Davydov, Y.; Dodokhov, V. Kh.; Efremov, A.; Fechtchenko, A.; Fedunov, A. G.; Galoyan, A.; Grigoryan, S.; Koshurnikov, E. K.; Lobanov, Y. Yu.; Lobanov, V. I.; Makarov, A. F.; Malinina, L. V.; Malyshev, V.; Olshevskiy, A. G.; Perevalova, E.; Piskun, A. A.; Pocheptsov, T.; Pontecorvo, G.; Rodionov, V.; Rogov, Y.; Salmin, R.; Samartsev, A.; Sapozhnikov, M. G.; Shabratova, G.; Skachkov, N. B.; Skachkova, A. N.; Strokovsky, E. A.; Suleimanov, M.; Teshev, R.; Tokmenin, V.; Uzhinsky, V.; Vodopianov, A.; Zaporozhets, S. A.; Zhuravlev, N. I.; Zorin, A. G.; Branford, D.; Glazier, D.; Watts, D.; Böhm, M.; Britting, A.; Eyrich, W.; Lehmann, A.; Pfaffinger, M.; Uhlig, F.; Dobbs, S.; Seth, K.; Tomaradze, A.; Xiao, T.; Bettoni, D.; Carassiti, V.; Cotta Ramusino, A.; Dalpiaz, P.; Drago, A.; Fioravanti, E.; Garzia, I.; Savrie, M.; Akishina, V.; Kisel, I.; Kozlov, G.; Pugach, M.; Zyzak, M.; Gianotti, P.; Guaraldo, C.; Lucherini, V.; Bersani, A.; Bracco, G.; Macri, M.; Parodi, R. F.; Biguenko, K.; Brinkmann, K.; Di Pietro, V.; Diehl, S.; Dormenev, V.; Drexler, P.; Düren, M.; Etzelmüller, E.; Galuska, M.; Gutz, E.; Hahn, C.; Hayrapetyan, A.; Kesselkaul, M.; Kühn, W.; Kuske, T.; Lange, J. S.; Liang, Y.; Metag, V.; Nanova, M.; Nazarenko, S.; Novotny, R.; Quagli, T.; Reiter, S.; Rieke, J.; Rosenbaum, C.; Schmidt, M.; Schnell, R.; Stenzel, H.; Thöring, U.; Ullrich, M.; Wagner, M. N.; Wasem, T.; Wohlfahrt, B.; Zaunick, H.; Ireland, D.; Rosner, G.; Seitz, B.; Deepak, P. N.; Kulkarni, A.; Apostolou, A.; Babai, M.; Kavatsyuk, M.; Lemmens, P. J.; Lindemulder, M.; Loehner, H.; Messchendorp, J.; Schakel, P.; Smit, H.; Tiemens, M.; van der Weele, J. C.; Veenstra, R.; Vejdani, S.; Dutta, K.; Kalita, K.; Kumar, A.; Roy, A.; Sohlbach, H.; Bai, M.; Bianchi, L.; Büscher, M.; Cao, L.; Cebulla, A.; Dosdall, R.; Gillitzer, A.; Goldenbaum, F.; Grunwald, D.; Herten, A.; Hu, Q.; Kemmerling, G.; Kleines, H.; Lehrach, A.; Nellen, R.; Ohm, H.; Orfanitski, S.; Prasuhn, D.; Prencipe, E.; Pütz, J.; Ritman, J.; Schadmand, S.; Sefzick, T.; Serdyuk, V.; Sterzenbach, G.; Stockmanns, T.; Wintz, P.; Wüstner, P.; Xu, H.; Zambanini, A.; Li, S.; Li, Z.; Sun, Z.; Xu, H.; Rigato, V.; Isaksson, L.; Achenbach, P.; Corell, O.; Denig, A.; Distler, M.; Hoek, M.; Karavdina, A.; Lauth, W.; Liu, Z.; Merkel, H.; Müller, U.; Pochodzalla, J.; Sanchez, S.; Schlimme, S.; Sfienti, C.; Thiel, M.; Ahmadi, H.; Ahmed, S.; Bleser, S.; Capozza, L.; Cardinali, M.; Dbeyssi, A.; Deiseroth, M.; Feldbauer, F.; Fritsch, M.; Fröhlich, B.; Jasinski, P.; Kang, D.; Khaneft, D.; Klasen, R.; Leithoff, H. H.; Lin, D.; Maas, F.; Maldaner, S.; Martínez, M.; Michel, M.; Mora Espí, M. C.; Morales Morales, C.; Motzko, C.; Nerling, F.; Noll, O.; Pflüger, S.; Pitka, A.; Rodríguez Piñeiro, D.; Sanchez-Lorente, A.; Steinen, M.; Valente, R.; Weber, T.; Zambrana, M.; Zimmermann, I.; Fedorov, A.; Korjik, M.; Missevitch, O.; Boukharov, A.; Malyshev, O.; Marishev, I.; Balanutsa, V.; Balanutsa, P.; Chernetsky, V.; Demekhin, A.; Dolgolenko, A.; Fedorets, P.; Gerasimov, A.; Goryachev, V.; Chandratre, V.; Datar, V.; Dutta, D.; Jha, V.; Kumawat, H.; Mohanty, A. K.; Parmar, A.; Roy, B.; Sonika, G.; Fritzsch, C.; Grieser, S.; Hergemöller, A.; Hetz, B.; Hüsken, N.; Khoukaz, A.; Wessels, J. P.; Khosonthongkee, K.; Kobdaj, C.; Limphirat, A.; Srisawad, P.; Yan, Y.; Barnyakov, M.; Barnyakov, A. Yu.; Beloborodov, K.; Blinov, A. E.; Blinov, V. E.; Bobrovnikov, V. S.; Kononov, S.; Kravchenko, E. A.; Kuyanov, I. A.; Martin, K.; Onuchin, A. P.; Serednyakov, S.; Sokolov, A.; Tikhonov, Y.; Atomssa, E.; Kunne, R.; Marchand, D.; Ramstein, B.; van de Wiele, J.; Wang, Y.; Boca, G.; Costanza, S.; Genova, P.; Montagna, P.; Rotondi, A.; Abramov, V.; Belikov, N.; Bukreeva, S.; Davidenko, A.; Derevschikov, A.; Goncharenko, Y.; Grishin, V.; Kachanov, V.; Kormilitsin, V.; Levin, A.; Melnik, Y.; Minaev, N.; Mochalov, V.; Morozov, D.; Nogach, L.; Poslavskiy, S.; Ryazantsev, A.; Ryzhikov, S.; Semenov, P.; Shein, I.; Uzunian, A.; Vasiliev, A.; Yakutin, A.; Tomasi-Gustafsson, E.; Roy, U.; Yabsley, B.; Belostotski, S.; Gavrilov, G.; Izotov, A.; Manaenkov, S.; Miklukho, O.; Veretennikov, D.; Zhdanov, A.; Makonyi, K.; Preston, M.; Tegner, P.; Wölbing, D.; Bäck, T.; Cederwall, B.; Rai, A. K.; Godre, S.; Calvo, D.; Coli, S.; De Remigis, P.; Filippi, A.; Giraudo, G.; Lusso, S.; Mazza, G.; Mignone, M.; Rivetti, A.; Wheadon, R.; Balestra, F.; Iazzi, F.; Introzzi, R.; Lavagno, A.; Olave, J.; Amoroso, A.; Bussa, M. P.; Busso, L.; De Mori, F.; Destefanis, M.; Fava, L.; Ferrero, L.; Greco, M.; Hu, J.; Lavezzi, L.; Maggiora, M.; Maniscalco, G.; Marcello, S.; Sosio, S.; Spataro, S.; Birsa, R.; Bradamante, F.; Bressan, A.; Martin, A.; Calen, H.; Ikegami Andersson, W.; Johansson, T.; Kupsc, A.; Marciniewski, P.; Papenbrock, M.; Pettersson, J.; Schönning, K.; Wolke, M.; Galnander, B.; Diaz, J.; Pothodi Chackara, V.; Chlopik, A.; Kesik, G.; Melnychuk, D.; Slowinski, B.; Trzcinski, A.; Wojciechowski, M.; Wronka, S.; Zwieglinski, B.; Bühler, P.; Marton, J.; Steinschaden, D.; Suzuki, K.; Widmann, E.; Zmeskal, J.
2016-10-01
Simulation results for future measurements of electromagnetic proton form factors at overlinePANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel bar{p}p→ e+e- is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e. bar{p}p→ π+π-, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance.
Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR
Singh, B. [Aligarth Muslim Univ., Aligarth (India). Physics Dept.; Erni, W.; Krusche, B. [Basel Univ. (Switzerland); Collaboration: The PANDA Collaboration; and others
2016-10-15
Simulation results for future measurements of electromagnetic proton form factors at PANDA(FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel anti pp → e{sup +}e{sup -} is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e. anti pp → π{sup +}π{sup -}, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance. (orig.)
Strange and charge symmetry violating electromagnetic form factors of the nucleon
Shanahan, P.E.
2016-01-01
We summarise recent work based on lattice QCD simulations of the electromagnetic form factors of the octet baryons from the CSSM/QCDSF/UKQCD collaborations. After an analysis of the simulation results using techniques to approach the infinite volume limit and the physical pseudoscalar masses at non-zero momentum transfer, the extrapolated proton and neutron form factors are found to be in excellent agreement with those extracted from experiment. Given the success of these calculations, we describe how the strange electromagnetic form factors may be estimated from these results under the same assumption of charge symmetry used in experimental determinations of those quantities. Motivated by the necessity of that assumption, we explore a method for determining the size of charge symmetry breaking effects using the same lattice results. (author)
Electromagnetic and Scalar Pion form factor in the Kroll-Lee-Zumino model
Dominguez, C.A.; Jottar, J.I.; Loewe, M.; Willers, B.
2009-01-01
The renormalizable Abelian quantum field theory model of Kroll, Lee, and Zumino is used at the one loop level to compute vertex corrections to the tree-level, Vector Meson Dominance (VMD) electromagnetic pion form factor. These corrections, together with the one-loop vacuum polarization contribution, imply a resulting electromagnetic pion form factor in excellent agreement with data in the whole range of accessible momentum transfers in the space-like region. The time-like form factor, which reproduces the Gounaris-Sakurai formula at and near the rho-meson peak, is unaffected by the vertex correction at order O(g 2 ). The KLZ model is also used to compute the scalar radius of the pion at the one loop level, finding π 2 > S =0.40fm 2 . This value implies for the low energy constant of chiral perturbation theory l-bar 4 =3.4
Skachkov, N.; Solovtsov, I.
1979-01-01
Based on the hamiltonian formulation of quantum field theory proposed by Kadyshevsky the three-dimensional relativistic approach is developed for describing the form factors of composite systems. The main features of the diagram technique appearing in the covariant hamiltonian formulation of field theory are discussed. The three-dimensional relativistic equation for the vertex function is derived and its connection with that for the quasipotential wave function is found. The expressions are obtained for the form factor of the system through equal-time two-particle wave functions both in momentum and relativistic configurational representations. An explicit expression for the form factor is found for the case of two-particle interaction through the Coulomb potential
Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR
Singh, B.; Krusche, B.; Steinacher, M.; Walford, N.; Liu, B.; Liu, H.; Liu, Z.; Shen, X.; Wang, C.; Zhao, J.; Albrecht, M.; Erlen, T.; Fink, M.; Heinsius, F.; Held, T.; Holtmann, T.; Jasper, S.; Keshk, I.; Koch, H.; Kopf, B.; Kuhlmann, M.; Kümmel, M.; Leiber, S.; Mikirtychyants, M.; Musiol, P.; Mustafa, A.; Pelizäus, M.; Pychy, J.; Richter, M.; Schnier, C.; Schröder, T.; Sowa, C.; Steinke, M.; Triffterer, T.; Wiedner, U.; Ball, M.; Beck, R.; Hammann, C.; Ketzer, B.; Kube, M.; Mahlberg, P.; Rossbach, M.; Schmidt, C.; Schmitz, R.; Thoma, U.; Urban, M.; Walther, D.; Wendel, C.; Wilson, A.; Bianconi, A.; Bragadireanu, M.; Caprini, M.; Pantea, D.; Patel, B.; Czyzycki, W.; Domagala, M.; Filo, G.; Jaworowski, J.; Krawczyk, M.; Lisowski, F.; Lisowski, E.; Michałek, M.; Poznański, P.; Płażek, J.; Korcyl, K.; Kozela, A.; Kulessa, P.; Lebiedowicz, P.; Pysz, K.; Schäfer, W.; Szczurek, A.; Fiutowski, T.; Idzik, M.; Mindur, B.; Przyborowski, D.; Swientek, K.; Biernat, J.; Kamys, B.; Kistryn, S.; Korcyl, G.; Krzemien, W.; Magiera, A.; Moskal, P.; Pyszniak, A.; Rudy, Z.; Salabura, P.; Smyrski, J.; Strzempek, P.; Wronska, A.; Augustin, I.; Böhm, R.; Lehmann, I.; Marinescu, D. Nicmorus; Schmitt, L.; Varentsov, V.; Al-Turany, M.; Belias, A.; Deppe, H.; Dzhygadlo, R.; Ehret, A.; Flemming, H.; Gerhardt, A.; Götzen, K.; Gromliuk, A.; Gruber, L.; Karabowicz, R.; Kliemt, R.; Krebs, M.; Kurilla, U.; Lehmann, D.; Löchner, S.; Lühning, J.; Lynen, U.; Orth, H.; Patsyuk, M.; Peters, K.; Saito, T.; Schepers, G.; Schmidt, C.J.; Schwarz, C.; Schwiening, J.; Täschner, A.; Traxler, M.; Ugur, C.; Voss, B.; Wieczorek, P.; Wilms, A.; Zühlsdorf, M.; Abazov, V.; Alexeev, G.; Arefiev, V.A.; Astakhov, V.; Barabanov, M. Yu.; Batyunya, B.V.; Davydov, Y.; Dodokhov, V. Kh.; Efremov, A.; Fechtchenko, A.; Fedunov, A.G.; Galoyan, A.; Grigoryan, S.; Koshurnikov, E.K.; Lobanov, Y. Yu.; Lobanov, V.I.; Makarov, A.F.; Malinina, L.V.; Malyshev, V.; Olshevskiy, A.G.; Perevalova, E.; Piskun, A.A.; Pocheptsov, T.; Pontecorvo, G.; Rodionov, V.; Rogov, Y.; Salmin, R.; Samartsev, A.; Sapozhnikov, M.G.; Shabratova, G.; Skachkov, N.B.; Skachkova, A.N.; Strokovsky, E.A.; Suleimanov, M.; Teshev, R.; Tokmenin, V.; Uzhinsky, V.; Vodopianov, A.; Zaporozhets, S.A.; Zhuravlev, N.I.; Zorin, A.G.; Branford, D.; Glazier, D.; Watts, D.; Böhm, M.; Britting, A.; Eyrich, W.; Lehmann, A.; Pfaffinger, M.; Uhlig, F.; Dobbs, S.; Seth, K.; Tomaradze, A.; Xiao, T.; Bettoni, D.; Carassiti, V.; Cotta Ramusino, A.; Dalpiaz, P.; Drago, A.; Fioravanti, E.; Garzia, I.; Savrie, M.; Akishina, V.; Kisel, I.; Kozlov, G.; Pugach, M.; Zyzak, M.; Gianotti, P.; Guaraldo, C.; Lucherini, V.; Bersani, A.; Bracco, G.; Macri, M.; Parodi, R.F.; Biguenko, K.; Brinkmann, K.; Di Pietro, V.; Diehl, S.; Dormenev, V.; Drexler, P.; Düren, M.; Etzelmüller, E.; Galuska, M.; Gutz, E.; Hahn, C.; Hayrapetyan, A.; Kesselkaul, M.; Kühn, W.; Kuske, T.; Lange, J.S.; Liang, Y.; Metag, V.; Nanova, M.; Nazarenko, S.; Novotny, R.; Quagli, T.; Reiter, S.; Rieke, J.; Rosenbaum, C.; Schmidt, M.; Schnell, R.; Stenzel, H.; Thöring, U.; Ullrich, M.; Wagner, M.N.; Wasem, T.; Wohlfahrt, B.; Zaunick, H.; Ireland, D.; Rosner, G.; Seitz, B.; Deepak, P.N.; Kulkarni, A.; Apostolou, A.; Babai, M.; Kavatsyuk, M.; Lemmens, P.J.; Lindemulder, M.; Loehner, H.; Messchendorp, J.; Schakel, P.; Smit, H.; Tiemens, M.; van der Weele, J.C.; Veenstra, R.; Vejdani, S.; Dutta, K.; Kalita, K.; Kumar, A.; Roy, A.; Sohlbach, H.; Bai, M.; Bianchi, L.; Büscher, M.; Cao, L.; Cebulla, A.; Dosdall, R.; Gillitzer, A.; Goldenbaum, F.; Grunwald, D.; Herten, A.; Hu, Q.; Kemmerling, G.; Kleines, H.; Lehrach, A.; Nellen, R.; Ohm, H.; Orfanitski, S.; Prasuhn, D.; Prencipe, E.; Pütz, J.; Ritman, J.; Schadmand, S.; Sefzick, T.; Serdyuk, V.; Sterzenbach, G.; Stockmanns, T.; Wintz, P.; Wüstner, P.; Xu, H.; Zambanini, A.; Li, S.; Li, Z.; Sun, Z.; Rigato, V.; Isaksson, L.; Achenbach, P.; Corell, O.; Denig, A.; Distler, M.; Hoek, M.; Karavdina, A.; Lauth, W.; Merkel, H.; Müller, U.; Pochodzalla, J.; Sanchez, S.; Schlimme, S.; Sfienti, C.; Thiel, M.; Ahmadi, H.; Ahmed, S.; Bleser, S.; Capozza, L.; Cardinali, M.; Dbeyssi, A.; Deiseroth, M.; Feldbauer, F.; Fritsch, M.; Fröhlich, B.; Jasinski, P.; Kang, D.; Khaneft, D.; Klasen, R.; Leithoff, H.H.; Lin, D.; Maas, F.; Maldaner, S.; Marta, M.; Michel, M.; Espí, M. C. Mora; Morales Morales, C.; Motzko, C.; Nerling, F.; Noll, O.; Pflüger, S.; Pitka, A.; Piñeiro, D. Rodríguez; Sanchez-Lorente, A.; Steinen, M.; Valente, R.; Weber, T.; Zambrana, M.; Zimmermann, I.; Fedorov, A.; Korjik, M.; Missevitch, O.; Boukharov, A.; Malyshev, O.; Marishev, I.; Balanutsa, V.; Balanutsa, P.; Chernetsky, V.; Demekhin, A.; Dolgolenko, A.; Fedorets, P.; Gerasimov, A.; Goryachev, V.; Chandratre, V.; Datar, V.; Dutta, D.; Jha, V.; Kumawat, H.; Mohanty, A.K.; Parmar, A.; Roy, B.; Sonika, G.; Fritzsch, C.; Grieser, S.; Hergemöller, A.; Hetz, B.; Hüsken, N.; Khoukaz, A.; Wessels, J.P.; Khosonthongkee, K.; Kobdaj, C.; Limphirat, A.; Srisawad, P.; Yan, Y.; Barnyakov, M.; Barnyakov, A. Yu.; Beloborodov, K.; Blinov, A.E.; Blinov, V.E.; Bobrovnikov, V.S.; Kononov, S.; Kravchenko, E.A.; Kuyanov, I.A.; Martin, K.; Onuchin, A.P.; Serednyakov, S.; Sokolov, A.; Tikhonov, Y.; Atomssa, E.; Kunne, R.; Marchand, D.; Ramstein, B.; van de Wiele, J.; Wang, Y.; Boca, G.; Costanza, S.; Genova, P.; Montagna, P.; Rotondi, A.; Abramov, V.; Belikov, N.; Bukreeva, S.; Davidenko, A.; Derevschikov, A.; Goncharenko, Y.; Grishin, V.; Kachanov, V.; Kormilitsin, V.; Levin, A.; Melnik, Y.; Minaev, N.; Mochalov, V.; Morozov, D.; Nogach, L.; Poslavskiy, S.; Ryazantsev, A.; Ryzhikov, S.; Semenov, P.; Shein, I.; Uzunian, A.; Vasiliev, A.; Yakutin, A.; Tomasi-Gustafsson, E.; Roy, U.; Yabsley, B.; Belostotski, S.; Gavrilov, G.; Izotov, A.; Manaenkov, S.; Miklukho, O.; Veretennikov, D.; Zhdanov, A.; Makonyi, K.; Preston, M.; Tegner, P.; Wölbing, D.; Bäck, T.; Cederwall, B.; Rai, A.K.; Godre, S.; Calvo, D.; Coli, S.; De Remigis, P.; Filippi, A.; Giraudo, G.; Lusso, S.; Mazza, G.; Mignone, M.; Rivetti, A.; Wheadon, R.; Balestra, F.; Iazzi, F.; Introzzi, R.; Lavagno, A.; Olave, J.; Amoroso, A.; Bussa, M.P.; Busso, L.; De Mori, F.; Destefanis, M.; Fava, L.; Ferrero, L.; Greco, M.; Hu, J.; Lavezzi, L.; Maggiora, M.; Maniscalco, G.; Marcello, S.; Sosio, S.; Spataro, S.; Birsa, R.; Bradamante, F.; Bressan, A.; Martin, A.; Calen, H.; Andersson, W. Ikegami; Johansson, T.; Kupsc, A.; Marciniewski, P.; Papenbrock, M.; Pettersson, J.; Schönning, K.; Wolke, M.; Galnander, B.; Diaz, J.; Chackara, V. Pothodi; Chlopik, A.; Kesik, G.; Melnychuk, D.; Slowinski, B.; Trzcinski, A.; Wojciechowski, M.; Wronka, S.; Zwieglinski, B.; Bühler, P.; Marton, J.; Steinschaden, D.; Suzuki, K.; Widmann, E.; Zmeskal, J.
2016-01-01
The results of simulations for future measurements of electromagnetic form factors at \\PANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision at which the proton form factors can be determined is estimated. The signal channel $\\bar p p \\to e^+ e^-$ is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e. the $\\bar p p \\to \\pi^+ \\pi^-$, is studied. Furthermore, the background versus signal efficiency, statistic and systematic uncertainties on the extracted proton form factors are evaluated using to the two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam condition and detector performances.
High Precision Measurement of the Proton Elastic Form Factor Ratio at Low Q2
Xiaohui Zhan
2009-12-01
A high precision measurement of the proton elastic form factor ratio µpGEp/GMp in the range Q2 = 0.3–0.7 GeV2/c2 was performed using recoil polarimetry in Jefferson Lab Hall A. In this low Q2 range, previous data from LEDEX [5] along with many fits and calculations [2, 3, 4] indicate substantial deviations of the ratio from unity. In this new measurement, with 80% polarized electron beam for 24 days, we are able to achieve <1% statistical uncertainty. Preliminary results are a few percent lower than expected from previous world data and fits, indicating a smaller GEp at this region. Beyond the intrinsic interest in nucleon structure, the improved form factor measurements also have implications for DVCS, determinations of the proton Zemach radius and strangeness form factors through parity violation experiments.
1/mQ corrections to form factors and extraction of |Vcb|
Liu, J.; Chao, K.
1997-01-01
Form factors for 0 - →0 - and 0 - →1 - mesonic transitions in the heavy quark limit and the 1/m Q corrections are analyzed model independently within the Bethe-Salpeter (BS) formalism. The analysis shows that the BS formalism has spin-flavor symmetry in the heavy quark limit and respects Luke's theorem when the 1/m Q corrections are taken into account. All form factors for B→D (*) transitions beyond the zero recoil point are estimated in a relativistic constituent quark model based on the BS formalism. Using these form factors we calculate the branching ratios for the semileptonic decays B→D (*) l + ν l and extract the Cabibbo-Kobayashi-Maskawa matrix element |V cb |. We get |V cb |=0.042±0.003 which is consistent with the current world average. copyright 1997 The American Physical Society
Holographic estimate of the meson cloud contribution to nucleon axial form factor
Ramalho, G.
2018-04-01
We use light-front holography to estimate the valence quark and the meson cloud contributions to the nucleon axial form factor. The free couplings of the holographic model are determined by the empirical data and by the information extracted from lattice QCD. The holographic model provides a good description of the empirical data when we consider a meson cloud mixture of about 30% in the physical nucleon state. The estimate of the valence quark contribution to the nucleon axial form factor compares well with the lattice QCD data for small pion masses. Our estimate of the meson cloud contribution to the nucleon axial form factor has a slower falloff with the square momentum transfer compared to typical estimates from quark models with meson cloud dressing.
Bethe Ansatz and exact form factors of the O(N) Gross Neveu-model
Babujian, Hrachya M.; Foerster, Angela; Karowski, Michael
2016-01-01
We apply previous results on the O(N) Bethe Ansatz http://dx.doi.org/10.1088/1751-8113/45/5/055207, http://arxiv.org/abs/1204.3479, http://dx.doi.org/10.1007/JHEP11(2013)089 to construct a general form factor formula for the O(N) Gross-Neveu model. We examine this formula for several operators, such as the energy momentum, the spin-field and the current. We also compare these results with the 1/N expansion of this model and obtain full agreement. We discuss bound state form factors, in particular for the three particle form factor of the field. In addition for the two particle case we prove a recursion relation for the K-functions of the higher level Bethe Ansatz.
New large-Nc relations for the electromagnetic nucleon-to-Δ form factors
Vladimir Pascalutsa; Marc Vanderhaeghen
2006-01-01
We establish relations which express the three N → Δ transition form factors in terms of the nucleon form factors. These relations are based on the known large-N c relation between the N → Δ electric quadrupole moment and the neutron charge radius, and a newly derived large-N c relation between the electric quadrupole (E2) and Coulomb quadrupole (C2) transitions. Namely, in the large-N c limit we find C2=E2. We show that these relations provide predictions for the N → Δ electromagnetic form factors which are found to be in very good agreement with experiment for moderate momentum transfers. They also provide constraints for the N → Δ GPDs
Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR
Singh, B.
2016-01-01
Simulation results for future measurements of electromagnetic proton form factors at PANDA(FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel anti pp → e + e - is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e. anti pp → π + π - , is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance. (orig.)
Quantum chromodynamics and hadron jets
Dokshitser, Y.L.; Dyakonov, D.I.
1979-07-01
These lectures are devoted to the description of the various properties of hard scattering processes with the participation of hadrons in the framework of Quantum Chromodynamics. We discuss in detail the validity and region of applicability of perturbation theory applied to hadron processes. Particular attention is paid to the question of the structure of quark and gluon jets produced in hard processes (as an example, e + e - annihilation into hadrons). In addition to giving a pedagogical review, we also present new results. (orig.)
Hadron collider physics at UCR
Kernan, A.; Shen, B.C.
1997-01-01
This paper describes the research work in high energy physics by the group at the University of California, Riverside. Work has been divided between hadron collider physics and e + -e - collider physics, and theoretical work. The hadron effort has been heavily involved in the startup activities of the D-Zero detector, commissioning and ongoing redesign. The lepton collider work has included work on TPC/2γ at PEP and the OPAL detector at LEP, as well as efforts on hadron machines
Thermodynamic model for the elastic form factor in diffraction scattering of protons
Grashin, A.F.; Evstratenko, A.S.; Lepeshkin, M.V.
1988-01-01
An explicit expression is obtained for the differential pp(p-bar)-scattering cross section in the diffraction-cone region by employing the thermodynamic model for the elastic form factor previously proposed in Ref. 4. Data for the energy region 16.3≤(s)/sup 1/2/ ≤546 GeV have been analyzed and significant deviations have been discovered from the commonly used approximations in the form of linear or quadratic exponentials
Constraints on the ωπ Form Factor from Analyticity and Unitarity
Ananthanarayan, B.; Caprini, Irinel; Kubis, Bastian
Form factors are important low-energy quantities and an accurate knowledge of these sheds light on the strong interactions. A variety of methods based on general principles have been developed to use information known in different energy regimes to constrain them in regions where experimental information needs to be tested precisely. Here we review our recent work on the electromagnetic ωπ form factor in a model-independent framework known as the method of unitarity bounds, partly motivated by the discre-pancies noted recently between the theoretical calculations of the form factor based on dispersion relations and certain experimental data measured from the decay ω → π0γ*. We have applied a modified dispersive formalism, which uses as input the discontinuity of the ωπ form factor calculated by unitarity below the ωπ threshold and an integral constraint on the square of its modulus above this threshold. The latter constraint was obtained by exploiting unitarity and the positivity of the spectral function of a QCD correlator, computed on the spacelike axis by operator product expansion and perturbative QCD. An alternative constraint is obtained by using data available at higher energies for evaluating an integral of the modulus squared with a suitable weight function. From these conditions we derived upper and lower bounds on the modulus of the ωπ form factor in the region below the ωπ threshold. The results confirm the existence of a disagreement between dispersion theory and experimental data on the ωπ form factor around 0:6 GeV, including those from NA60 published in 2016.
Form factors for semileptonic Bs→Klν decays in lattice QCD
Bahr, Felix Tobias
2015-01-01
We present an exploratory study of the calculation of the form factor f + (q 2 ) for the semileptonic decay B s →Klν in large-volume lattice QCD simulations with two dynamical sea quark flavours using O(a) improved Wilson fermions. We discuss the computation of relevant two- and three-point functions and consider complementary methods how these can be combined to obtain the form factor. In particular, we put forward the strategy of a combined fit in which data of all correlators enter and which has as fit parameters energies and amplitudes of the correlators and the form factor. The b quark is treated in HQET; our present analysis focuses on the static limit. Meanwhile, we have developed the code and performed the measurements of all needed O(1/m h ) corrections which will be used as soon as their coefficients will have been computed by the ALPHA collaboration. In order to be able to measure the form factor at the same value of the momentum transfer q 2 on all ensembles, we impose twisted boundary conditions on the s and b quarks that allow for a free tuning of the quark momenta and thus of q 2 . We perform measurements on a subset of N f =2 CLS gauge configurations, obtaining the form factor at three different lattice spacings and roughly the same pion mass of about 330 MeV. Using these, we carry out a continuum extrapolation and observe that it is relatively flat in a 2 . A measurement at a different pion mass indicates that quark mass effects are small. We compare our continuum value of the form factor with recently published results of other collaborations and observe a good agreement.
Lattice study of D and D{sub s} meson form factors with twisted boundary conditions
Li, Ning; Wu, Ya-Jie [Xi' an Technological University, School of Science, Xi' an (China)
2017-03-15
We present results on the D and D{sub s} meson electromagnetic form factors using N{sub f} = 2 twisted mass Lattice Quantum Chromodynamics (LQCD) gauge configurations. In this simulation, to access spatial components of momenta that are different from the integer multiples of 2π/L, we apply twisted boundary conditions to compute corresponding correlation functions. Electromagnetic form factors with more small four-momentum transfer are determined, and further we fit the electromagnetic charge radius for D and D{sub s} mesons, respectively. (orig.)
On the ππ continuum in the nucleon form factors and the proton radius puzzle
Hoferichter, M.; Kubis, B.; Ruiz de Elvira, J.; Hammer, H.-W.; Meißner, U.-G.
2016-11-01
We present an improved determination of the ππ continuum contribution to the isovector spectral functions of the nucleon electromagnetic form factors. Our analysis includes the most up-to-date results for the ππ→bar{N} N partial waves extracted from Roy-Steiner equations, consistent input for the pion vector form factor, and a thorough discussion of isospin-violating effects and uncertainty estimates. As an application, we consider the ππ contribution to the isovector electric and magnetic radii by means of sum rules, which, in combination with the accurately known neutron electric radius, are found to slightly prefer a small proton charge radius.
On the ππ continuum in the nucleon form factors and the proton radius puzzle
Hoferichter, M.; Kubis, B.; Ruiz de Elvira, J.; Hammer, H.W.; Meissner, U.G.
2016-01-01
We present an improved determination of the ππ continuum contribution to the isovector spectral functions of the nucleon electromagnetic form factors. Our analysis includes the most up-to-date results for the ππ → anti NN partial waves extracted from Roy-Steiner equations, consistent input for the pion vector form factor, and a thorough discussion of isospin-violating effects and uncertainty estimates. As an application, we consider the ππ contribution to the isovector electric and magnetic radii by means of sum rules, which, in combination with the accurately known neutron electric radius, are found to slightly prefer a small proton charge radius. (orig.)
Analysis of the J /ψ →π0γ* transition form factor
Kubis, Bastian; Niecknig, Franz
2015-02-01
In view of the first measurement of the branching fraction for J /ψ →π0e+e- by the BESIII collaboration, we analyze what can be learned on the corresponding transition form factor using dispersion theory. We show that light-quark degrees of freedom dominate the spectral function, in particular two-pion intermediate states. Estimating the effects of multipion states as well as charmonium, we arrive at a prediction for the complete form factor that should be scrutinized experimentally in the future.
Charge symmetry violation in the electromagnetic form factors of the proton
Shanahan, P.E.; Thomas, A.W.; Young, R.D.; Zanotti, J.M.; Pleiter, D.; Stueben, H.
2015-03-01
Experimental tests of QCD through its predictions for the strange-quark content of the proton have been drastically restricted by our lack of knowledge of the violation of charge symmetry (CSV). We find unexpectedly tiny CSV in the proton's electromagnetic form factors by performing the first extraction of these quantities based on an analysis of lattice QCD data. The resulting values are an order of magnitude smaller than current bounds on proton strangeness from parity violating electron-proton scattering experiments. This result paves the way for a new generation of experimental measurements of the proton's strange form factors to challenge the predictions of QCD.
Extraction of the bare form factors for the semi-leptonic Bs decays
Bahr, F.; Banerjee, D.; Koren, M.; Simma, H.; Sommer, R.
2017-01-01
The computation of the form factors for the B s →lν decay is presented. The b quark is treated by means of Heavy Quark Effective Theory, currently in the static approximation. In these proceedings we discuss the extraction of the bare matrix elements from lattice data through a combined fit to two- and three-point correlation functions, as well as by considering suitable ratios. The different methods agree concerning the extracted form factors and approximately 2% accuracy is reached. The non-perturbative renormalization and matching to QCD is described in accompanying proceedings.
On the ππ continuum in the nucleon form factors and the proton radius puzzle
Hoferichter, M. [University of Washington, Institute for Nuclear Theory, Seattle, WA (United States); Kubis, B.; Ruiz de Elvira, J. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Bonn (Germany); Hammer, H.W. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, ExtreMe Matter Institute EMMI, Darmstadt (Germany); Meissner, U.G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Bonn (Germany); Institut fuer Kernphysik, Institute for Advanced Simulation, and Juelich Center for Hadron Physics, Forschungszentrum Juelich, Juelich (Germany)
2016-11-15
We present an improved determination of the ππ continuum contribution to the isovector spectral functions of the nucleon electromagnetic form factors. Our analysis includes the most up-to-date results for the ππ → anti NN partial waves extracted from Roy-Steiner equations, consistent input for the pion vector form factor, and a thorough discussion of isospin-violating effects and uncertainty estimates. As an application, we consider the ππ contribution to the isovector electric and magnetic radii by means of sum rules, which, in combination with the accurately known neutron electric radius, are found to slightly prefer a small proton charge radius. (orig.)
Strange quark content in the nucleon and the strange quark vector current form factors
Dubnicka, S.; Dubnickova, A.Z.
1996-12-01
A behaviour of the form factors of the nucleon matrix element of the strange quark vector current in the momentum range of the planned measurements in MIT/Bates and CEBAF is predicted theoretically without using any of the experimental information on the nucleon electromagnetic structure. The corresponding leading nonvanishing moments of the nucleon vector strangeness distribution are comparable with the values obtained by other authors in the framework of the method based on the vector meson pole fit of the isoscalar electromagnetic form factors of the nucleon. (author). 16 refs, 2 figs
Constructing Nucleon Operators on a Lattice for Form Factors with High Momentum Transfer
Syritsyn, Sergey [Stony Brook Univ., NY (United States); Gambhir, Arjun S. [College of William and Mary, Williamsburg, VA (United States); Musch, Bernhard U. [Univ. of Regensburg (Germany); Orginos, Konstantinos [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2017-05-01
We present preliminary results of computing nucleon form factor at high momentum transfer using the 'boosted' or 'momentum' smearing. We use gauge configurations generated with N f = 2 + 1dynamical Wilson-clover fermions and study the connected as well as disconnected contributions to the nucleon form factors. Our initial results indicate that boosted smearing helps to improve the signal for nucleon correlators at high momentum. However, we also find evidence for large excited state contributions, which will likely require variational analysis to isolate the boosted nucleon ground state.
Parity Violation in Elastic Electron-Proton Scattering and the Proton's Strange Magnetic Form Factor
Spayde, D. T.; Averett, T.; Barkhuff, D.; Beck, D. H.; Beise, E. J.; Benson, C.; Breuer, H.; Carr, R.; Covrig, S.; DelCorso, J.
2000-01-01
We report a new measurement of the parity-violating asymmetry in elastic electron scattering from the proton at backward scattering angles. This asymmetry is sensitive to the strange magnetic form factor of the proton as well as electroweak axial radiative corrections. The new measurement of A=-4.92±0.61±0.73 ppm provides a significant constraint on these quantities. The implications for the strange magnetic form factor are discussed in the context of theoretical estimates for the axial corrections. (c) 2000 The American Physical Society
Q resolution calculation of small angle neutron scattering spectrometer and analysis of form factor
Chen Liang; Peng Mei; Wang Yan; Sun Liangwei; Chen Bo
2011-01-01
The calculational methods of Small Angle Neutron Scattering (SANS) spectrometer Q resolution function and its correlative Q standard difference were introduced. The effects of Q standard difference were analysed with the geometry lay out of spectrometer and the spread of neutron wavelength. The one dimension Q resolution Gaussian function were analysed. The form factor curve of ideal solid sphere and two different instrument arrangement parameter was convoluted respectively and the different smearing curve of form factor was obtained. The combination of using the Q resolution function to more accurately analysis SANS data. (authors)
Extraction of the bare form factors for the semi-leptonic B{sub s} decays
Bahr, F.; Banerjee, D.; Koren, M.; Simma, H.; Sommer, R. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2017-01-12
The computation of the form factors for the B{sub s}→lν decay is presented. The b quark is treated by means of Heavy Quark Effective Theory, currently in the static approximation. In these proceedings we discuss the extraction of the bare matrix elements from lattice data through a combined fit to two- and three-point correlation functions, as well as by considering suitable ratios. The different methods agree concerning the extracted form factors and approximately 2% accuracy is reached. The non-perturbative renormalization and matching to QCD is described in accompanying proceedings.
Transverse Momentum Correlations in Hadronic Z decays
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; 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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.
Counting and tensorial properties of twist-two helicity-flip nucleon form factors
Chen Zhang; Ji Xiangdong
2005-01-01
We perform a systematic analysis on the off-forward matrix elements of the twist-two quark and gluon helicity-flip operators. By matching the allowed quantum numbers and their crossing channel counterparts (a method developed by Ji and Lebed), we systematically count the number of independent nucleon form factors in off-forward scattering of matrix elements of these quark and gluon spin-flip operators. In particular, we find that the numbers of independent nucleon form factors of twist-two, helicity-flip quark (gluon) operators are 2n-1 (2n-5) if n is odd, and 2n-2 (2n-6) if n is even, with n≥2 (n≥4). We also analyze and write down the tensorial/Lorentz structure and kinematic factors of the expansion of these operators' matrix elements in terms of the independent form factors. These generalized form factors define the off-forward quark and gluon helicity-flip distributions in the literature