MEASUREMENT OF POLARIZED QUARK DISTRIBUTIONS AT HERMES

2003 ◽  
Vol 18 (08) ◽  
pp. 1185-1192
Author(s):  
◽  
STEFAN BERNREUTHER
Keyword(s):  
Cross Section ◽  
Kinematic Range ◽  
Spin Asymmetries ◽  
Double Spin ◽  
Hermes Experiment ◽  
Down Quark ◽  
Up Quark ◽  
Rich Detector ◽  
The Individual ◽  
Quark Flavors

The HERMES experiment has measured double spin asymmetries in the cross section for deep–inelastic scattering of longitudinally polarized positrons on longitudinally polarized 3 He (1995), 1 H (1996/97), and 2 D (1998) targets. A kinematic range of 0.023 < x < 0.6, and 1 GeV 2 < Q2 < 15 GeV 2 has been covered. From these asymmetries, based on inclusive and semi–inclusive measurements, polarized quark distributions are extracted as a function of x for up [Formula: see text] and down [Formula: see text] flavors as well as for valence and sea quarks. In the measured range, the up quark polarization is positive while the down quark polarization is negative. The sea quark polarization is compatible with zero. In this analysis all sea quark polarizations have been assumed to be flavor symmetric. Presently HERMES is analyzing a high statistics 2 D data sample taken in 1999-2000. For these data it is possible to identify pions and kaons with a RICH detector which was installed in 1998. This will enable an extraction of the individual sea quark flavors [Formula: see text], [Formula: see text], and [Formula: see text] without any symmetry assumptions.

scholarly journals The Chosen Aspects of Skew Rolling of Hollow Stepped Shafts

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 764
Author(s):  
Jarosław Bartnicki ◽  
Yingxiang Xia ◽  
Xuedao Shu
Keyword(s):  
Cross Section ◽  
Rolling Mill ◽  
Metal Flow ◽  
Experimental Tests ◽  
Rolling Process ◽  
Numerical Control ◽  
Technological Parameters ◽  
Flow Mechanisms ◽  
The Individual ◽  
Skew Rolling

The paper presents chosen aspects of the skew rolling process of hollow stepped products with the use of a skew rolling mill designed and manufactured at the Lublin University of Technology. This machine is characterized by the numerical control of spacing between the working rolls and the sequence of the gripper axial movement, which allows for the individual programming of the obtained shapes of parts such as stepped axles and shafts. The length of these zones and the values of possibly realizable cross-section reduction and obtained outlines are the subject of this research paper. The chosen results regarding the influence of the technological parameters used on the course of the process are shown in the present study. Numerical modelling using the finite element method in Simufact Forming, as well as the results of experimental tests performed in a skew rolling mill, were applied in the conducted research. The work takes into account the influence of cross-section reduction of the hollow parts and the feed rate per rotation on the metal flow mechanisms in the skew rolling process. The presented results concern the obtained dimensional deviations and changes in the wall thickness determining the proper choice of technological parameters for hollow parts formed by the skew rolling method. Knowledge about the cause of the occurrence of these limitations is very important for the development of this technology and the choice of the process parameters.

The Study of Chinese Political Culture

1966 ◽  
Vol 18 (3) ◽  
pp. 503-524 ◽  
Author(s):  
John W. Lewis
Keyword(s):  
Political Culture ◽  
Cross Section ◽  
Scholarly Publication ◽  
Communist China ◽  
The Individual ◽  
Chinese Political Culture

These seven recent works typify a cross section of scholarly publication on the Chinese People's Republic, its history, present operation, and prospects. Taken together, they provide the basis for some remarks on the study of Chinese “political culture.” Rather than attempt a full review of the individual works, this brief article will examine some of their assumptions and indirectly comment on the literature they represent. Each book reflects a prodigious scholarly effort and has received in various other journals a complete appraisal of its intellectual value. In general it may be fairly said that these volumes do not constitute significant breakthroughs of knowledge. They do, however, bring together and analyze important bodies of data on Communist China.

scholarly journals STANDARD MODEL HIGGS COMBINED RESULT FROM CDF

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 825-827
Author(s):  
◽  
JOÃO GUIMARÃES DA COSTA
Keyword(s):  
Standard Model ◽  
Cross Section ◽  
Z Boson ◽  
Decay Channel ◽  
Vector Boson ◽  
Associated Production ◽  
The Standard Model ◽  
The Individual ◽  
Cross Section Limit

The Tevatron is expected to be most sensitive to the Standard Model Higgs in its associated production with a W or Z boson. The Collider Detector at Fermilab (CDF) has performed individual searches for such production in each decay channel of the vector boson, assuming that the Higgs decays to [Formula: see text]. These searches use data collected by CDF during the 1992-95 run. The individual results are reviewed, and a combined cross section limit is presented.

THE ABSORPTION OF HIGH-ENERGY RADIATION, A MONTE CARLO STUDY: II. SPHERICAL GEOMETRY

1963 ◽  
Vol 41 (4) ◽  
pp. 651-663
Author(s):  
N. R. Steenberg
Keyword(s):  
Cross Section ◽  
Spherical Geometry ◽  
Monte Carlo Study ◽  
Nuclear Data ◽  
High Energy ◽  
Rare Gas ◽  
Nuclear Radius ◽  
Rigid Spheres ◽  
High Energy Radiation ◽  
The Individual

The absorption of radiation in a spherical obstacle composed of rigid spheres has been studied. The result is the absorption cross section of such an obstacle as a function of the free cross section and the number A of the individual spheres and of packing density. It is found that the usual rare-gas formula represents the cross section adequately. The analysis is applied to nuclear data for the absorption of 25-Bev/c protons by nuclei. It is found that for a nuclear radius R = r0A1/3 + δ, where δ is the radius of the nucleon, r0 = 1.17 fermi, δ = 1.05 fermi, and an average nucleon transparency a2 = 0.30 is consistent with the data.

scholarly journals Double spin asymmetries through QCD instantons

2014 ◽  
Vol 90 (11) ◽  
Author(s):  
Yachao Qian ◽  
Ismail Zahed
Keyword(s):  
Spin Asymmetries ◽  
Double Spin

Travel and Travelers

2010 ◽  
Author(s):  
James Muldoon
Keyword(s):  
Cross Section ◽  
Medieval Literature ◽  
Canterbury Tales ◽  
Common Belief ◽  
China And India ◽  
The Bible ◽  
The World ◽  
English Society ◽  
The Individual ◽  
The Village

There is a common belief that medieval men and women lived their lives within a narrow geographical and psychological space, the village and the neighboring fields for the most part. According to this opinion, it was not until the Renaissance and the voyages of Columbus and those who followed him that Europeans became aware of the wider world around them and shed the blinders that had constrained them for centuries. What makes this opinion so at odds with medieval reality is that one of the most famous and widely read pieces of medieval literature, Chaucer’s Canterbury Tales, deals with the travels of a group of medieval Christians who range from a crusading knight to farm laborers, individuals representing a cross section of the middling levels of 14th-century English society. Merchants, crusaders, missionaries, pilgrims, exiles, and others motivated by simple restless curiosity traveled around Europe, to the edges of the Christian world, and then all the way to China and India and, sailing westward, to North America. Travel and travel imagery also played an important role in Christian life. The Bible begins with the creation of the world, traces the course of God’s involvement with his people over time, and concludes with the end of the world, the ultimate goal of mankind as defined by the Creator. The life of the individual Christian is a pilgrimage within this context, the movement of the soul to union with God, a microcosm of this larger narrative. It is no coincidence that the most famous work of medieval literature, Dante’s Divine Comedy, was cast as a travel tale.

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