Download or read book Moments of the Proton Structure Functions written by Gong Ping Yeh and published by . This book was released on 1975 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Self Consistent Data Analysis of the Proton Structure Function G1 and Extraction of Its Moments written by C. Keppel and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The reanalysis of all available world data on the longitudinal asymmetry A{sub {parallel}} is presented. The proton structure function g1 was extracted within a unique framework of data inputs and assumptions. These data allowed for a reliable evaluation of moments of the structure function g{sub 1} in the Q{sup 2} range from 0.2 up to 30 GeV{sup 2}. The Q{sup 2} evolution of the moments was studied in QCD by means of Operator Product Expansion (OPE).
Download or read book Global Analysis of Data on the Proton Structure Function G1 and Extraction of Its Moments written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Inspired by recent measurements with the CLAS detector at Jefferson Lab, we perform a self-consistent analysis of world data on the proton structure function g1 in the range 0.17
Download or read book Moments of the Proton F2 Structure Function at Low Q2 written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors review the status of inclusive electron-proton scattering F2 structure function data in both the nucleon resonance region and the deep inelastic region, at momentum transfers below 5 (GeV/c)2. From these data they construct moments of F2, down to momentum transfers of Q2(almost equal to)0.1(GeV/c)2. The second moment is only slowly varying with Q2 down to Q2(almost equal to)1, which is a reflection of duality. Below Q2 of 1 (GeV/c)2, the Q2 dependence of the moments is predominantly governed by the elastic contribution, whereas the inelastic channels still seem governed by local duality.
Download or read book Spin Structure Moments of the Proton and Deuteron written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Moments of the spin structure functions g1 and g2 of the proton and deuteron have been measured in the resonance region at intermediate four momentum transfer. We perform a Nachtmann moment analysis of this data, along with isovector and isoscalar combinations, in order to rigorously account for target mass effects. This analysis provides the first definitive evidence for dynamic higher twists.
Download or read book Evaluation of the Higher Twist Contribution to the Moments of Proton Structure Functions F2 and G1 written by Mikhail Osipenko and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We performed the measurement of the inclusive electron scattering off the proton in the resonance region (W2.5 GeV) at momentum transfer Q2 below 4.5 (GeV/c){sup 2} with the CLAS detector. The large acceptance of CLAS provided an access to a large, continuous two-dimensional kinematic domain in Q2 and x, allowing therefore an integration of the data at fixed Q2 over x-interval. The covered x-interval at each measured Q2 value is sufficient for an evaluation of the higher moments (n2). From these data we extracted the structure function F2 and, by including other world data, we studied the Q2 evolution of its moments, Mn(Q2), in order to estimate the higher twist contributions. A similar experiment with polarized proton target is completed at CLAS. These new data allow an accurate determination of higher moments of the proton structure function g1. A preliminary phenomenological analysis indicates an excess of the higher twist contribution in the spin-dependent structure function with respect to the spin-independent one.
Download or read book Moments of F2 Structure Functions and Multiparton Correlations in Nuclei written by and published by . This book was released on 2002 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: The inclusive inelastic electron scattering o the proton was measured at five different beam energies 1.5, 2.5, 4.0, 4.2 and 4.4 GeV. The data were taken, during February-March 1999, on a liquid hydrogen target with the CLAS detector installed in Hall-B of the Thomas Jefferson National Accelerator Facility (TJNAF). The obtained high statistics and high precision data appear to be in good agreement with previously measured world data and permit to integrate experimental values of F2 over x at fixed Q2 , allowing for the first time the evaluation of its experimental moments at low and moderate values of Q2 . In a combined analysis of CLAS and world data, the Q2-evolution of the experimental moments was explored in the range from 0.3 up to 100 GeV2 . This offered a unique possibility to trace changes of the proton structure function from hard DIS down to the non-perturbative regime through the transition region, which is of particular interest for the TJNAF physics program. The obtained experimental moments allowed to perform a separation between the leading twist, calculable in the framework of the perturbative QCD (pQCD), and higher twists, treated effectively. A comparison with theoretical predictions based either on lattice QCD simulations or obtained within models of the nucleon structure may represent an important test of our understanding of the nucleon structure as observed at large wavelengths.
Download or read book The Spin Structure of the Proton written by Steven D. Bass and published by World Scientific. This book was released on 2008 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the main challenges in nuclear and particle physics in the last 20 years has been to understand how the proton''s spin is built up from its quark and gluon constituents. Quark models generally predict that about 60% of the proton''s spin should be carried by the spin of the quarks inside, whereas high energy scattering experiments have shown that the quark spin contribution is small OCo only about 30%. This result has been the underlying motivation for about 1000 theoretical papers and a global program of dedicated spin experiments at BNL, CERN, DESY and Jefferson Laboratory to map the individual quark and gluon angular momentum contributions to the proton''s spin, which are now yielding exciting results. This book gives an overview of the present status of the field: what is new in the data and what can be expected in the next few years. The emphasis is on the main physical ideas and the interpretation of spin data. The interface between QCD spin physics and the famous axial U(1) problem of QCD (eta and etaprime meson physics) is also highlighted. Sample Chapter(s). Chapter 1: Introduction (159 KB). Contents: Spin Experiments and Data; Dispersion Relations and Spin Sum Rules; g 1 Spin Sum Rules; Fixed Poles; The Axial Anomaly, Gluon topology and g (0) A; Chiral Symmetry and Axial U(1) Dynamics; QCD Inspired Models of the Proton Spin Problem; The Spin-Flavour Structure of the Proton; QCD Fits to g 1 Data; Polarized Quark Distributions; Polarized Glue o g(x, Q 2 ); Transversity; Deeply Virtual Compton Scattering and Exclusive Processes; Polarized Photon Structure Functions; Conclusions and Open Questions: How Does the Proton Spin?. Readership: Academics, as well as physicists working on particle and nuclear physics at the interface of theory and experiment.
Download or read book Measurement of the Proton Structure Function XF3 in High Q2 DID Events Using ZEUS Data written by Licenciada Amaya López-Durán Viani and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neutron Structure Function Moments at Leading Twist written by S. Simula and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The experimental data on F2 structure functions of the proton and deuteron were used to construct their moments. In particular, recent measurements performed with CLAS detector at Jefferson Lab allowed to extend our knowledge of structure functions in the large-x region. The phenomenological analysis of these experimental moments in terms of the Operator Product Expansion permitted to separate the leading and higher twist contributions. Applying nuclear corrections to extracted deuteron moments we obtained the contribution of the neutron. Combining leading twist moments of the neutron and proton we found d/u ratio at x->1 approaching 0, although 1/5 value could not be excluded. The twist expansion analysis suggests that the contamination of higher twists influences the extraction of the d/u ratio at x->1 even at Q2-scale as large as 12 (GeV/c){sup 2}.
Download or read book Measurement of the Proton Structure Function F2 at HERA written by Mikihiko Nakao and published by . This book was released on 1994 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Moments of the Spin Structure Functions G1p and G1d for 0 05 Q2 3 0 GeV2 written by and published by . This book was released on 2009 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The spin structure functions $g_1$ for the proton and the deuteron have been measured over a wide kinematic range in $x$ and \Q2 using 1.6 and 5.7 GeV longitudinally polarized electrons incident upon polarized NH$_3$ and ND$_3$ targets at Jefferson Lab. Scattered electrons were detected in the CEBAF Large Acceptance Spectrometer, for $0.05
Download or read book The Structure of the Proton written by R. G. Roberts and published by Cambridge University Press. This book was released on 1993-11-26 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: This graduate/research level book describes our present knowledge of protons and neutrons, the particles which make up the nucleus of the atom. Experiments using high energy electrons, muons and neutrinos reveal the proton as being made up of point-like constituents, quarks. The strong forces which bind the quarks together are described in terms of the modern theory of quantum chromodynamics (QCD), the â€~glue' binding the quarks being mediated by new constituents called gluons. Larger and new particle accelerators probe the interactions between quarks and gluons at shorter distances. The understanding of this detailed substructure and of the fundamental forces responsible is one of the keys to unravelling the physics of the structure of matter. This book will be of interest to all theoretical and experimental particle physicists.
Download or read book Measurement of the Ratio of the Neutron and Proton Structure Functions F2 in Inelastic Muon Scattering written by Robert D. Kennedy and published by . This book was released on 1992 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Proton Structure Function F 2 in the Resonance Region written by M. Taiuti and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Unique measurement of the proton structure function F2 in a wide two-dimensional region of x and Q**2 has been reported. The accessible kinematics covers entire resonance region up to W=2.5 GeV in the Q**2 interval from 0.1 to 4.5 GeV**2. Obtained data allowed for the first time an evaluation of moments of the structure function F2 directly from experimental data as well as an intensive study of the Bloom-Gilman duality phenomenon.
Download or read book Proton Structure Functions at Small X written by and published by . This book was released on 2015 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton structure functions are measured in electron-proton collision through inelastic scattering of virtual photons with virtuality Q on protons; x denotes the momentum fraction carried by the struck parton. Proton structure functions are currently described with excellent accuracy in terms of scale dependent parton distribution functions, defined in terms of collinear factorization and DGLAP evolution in Q. With decreasing x however, parton densities increase and are ultimately expected to saturate. In this regime DGLAP evolution will finally break down and non-linear evolution equations w.r.t x are expected to take over. In the first part of the talk we present recent result on an implementation of physical DGLAP evolution. Unlike the conventional description in terms of parton distribution functions, the former describes directly the Q dependence of the measured structure functions. It is therefore physical insensitive to factorization scheme and scale ambiguities. It therefore provides a more stringent test of DGLAP evolution and eases the manifestation of (non-linear) small x effects. It however requires a precise measurement of both structure functions F2 and FL, which will be only possible at future facilities, such as an Electron Ion Collider. In the second part we present a recent analysis of the small x region of the combined HERA data on the structure function F2. We demonstrate that (linear) next-to-leading order BFKL evolution describes the effective Pomeron intercept, determined from the combined HERA data, once a resummation of collinear enhanced terms is included and the renormalization scale is fixed using the BLM optimal scale setting procedure. We also provide a detailed description of the Q and x dependence of the full structure functions F2 in the small x region, as measured at HERA. As a result, predictions for the structure function FL are found to be in agreement with the existing HERA data.
Download or read book Experimental Moments of the Nucleon Structure Function F2 written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental data on the F2 structure functions of the proton and deuteron, including recent results from CLAS at Jefferson Lab, have been used to construct their n=12 moments. A comprehensive analysis of the moments in terms of the operator product expansion has been performed to separate the moments into leading and higher twist contributions. Particular attention was paid to the issue of nuclear corrections in the deuteron, when extracting the neutron moments from data. The difference between the proton and neutron moments was compared directly with lattice QCD simulations. Combining leading twist moments of the neutron and proton we found the d/u ratio at x-1 approaching 0, although the precision of the data did not allow to exclude the 1/5 value. The higher twist components of the proton and neutron moments suggest that multi-parton correlations are isospin independent.
