Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The ...asymmetry depends on the azimuthal angles of both the pion (phi) and the target spin axis (phi(S)) about the virtual-photon direction and relative to the lepton scattering plane. The extracted Fourier component sin((phi+phi(S))(pi)(UT) is a signal of the previously unmeasured quark transversity distribution, in conjunction with the Collins fragmentation function, also unknown. The component sin((phi-phi(S)(pi)(UT) arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson production.
Review of particle physics Hagiwara, K; Nakamura, K; Amsler, C ...
Physical review. D, Particles and fields,
07/2002, Letnik:
66, Številka:
1
Journal Article
Recenzirano
This biennial Review summarizes much of Particle Physics Using data from previous editions, plus 2205 new measurements from 667 papers, we list, evaluate, and average measured properties of gauge ...bosons, leptons, quarks, mesons, and baryons We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles All the particle properties and search limits are listed in Summary Tables We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics This edition features expanded coverage of CP violation in B mesons and of neutrino oscillations For the first time we cover searches for evidence of extra dimensions (both in the particle listings and in a new review) Another new review is on Grand Unified Theories A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review All tables, listings, and reviews (and errata) are also available on the Particle Data Group website http //pdg 1b1 gov.
Measurements of Drell-Yan lepton-pair production cross sections and associated angular correlations can provide unique insight into perturbative Quantum Chromodynamics in the absence of colour flow ...between initial and final states, the V-A nature of electroweak interactions, as well as enhance the knowledge of parton distribution functions in the proton. Drell-Yan production is also an important source of background for other Standard-Model processes such as Higgs-boson production as well as for new phenomena, particularly at high dilepton invariant mass, and so must be evaluated precisely at the Large Hadron Collider. The measurements presented in this note are based on approximately 5 fb super(-1) of data collected at a centre-of-mass energy of 7 TeV in 2011 with the ATLAS detector based at the CERN Laboratory.
We present a measurement of the longitudinal spin asymmetry A(||) in photoproduction of pairs of hadrons with high transverse momentum p(T). Data were accumulated by the HERMES experiment using a ...27.5 GeV polarized positron beam and a polarized hydrogen target internal to the HERA storage ring. For h(+)h(-) pairs with p(h(1))(T)>1.5 GeV/c and p(h(2))(T)>1.0 GeV/c, the measured asymmetry is A(||) = -0. 28+/-0.12(stat)+/-0.02(syst). This negative value is in contrast to the positive asymmetries typically measured in deep inelastic scattering from protons, and is interpreted to arise from a positive gluon polarization.
This volume contains pedagogical lectures on particle physics, nuclear astrophysics, relativistic heavy ion interactions and gravitational waves. In addition, numerous contributions provide ...up-to-date information on new experimental results at colliders, underground laboratories and nuclear astrophysics. This combination of pedagogical talks and topical short talks provide a comprehensive amount of information to the researchers.
The Lake Louise Winter Institute is held annually to explore recent trends in physics. Pedagogical and review lectures are presented by invited experts. A topical workshop is held in conjunction with ...the Institute, with contributed presentations by participants.
The pseudorapidity region
2.5
<
|
η
|
<
4.0
in ATLAS is a particularly complex transition zone between the endcap and forward calorimeters. A set-up consisting of
1
4
resp.
1
8
of the full azimuthal ...acceptance of the ATLAS liquid argon endcap and forward calorimeters has been exposed to beams of electrons, pions and muons in the energy range
E
⩽
200
GeV
at the CERN SPS. Data have been taken in the endcap and forward calorimeter regions as well as in the transition region. This beam test set-up corresponds very closely to the geometry and support structures in ATLAS. A detailed study of the performance in the endcap and forward calorimeter regions is described. The data are compared with MC simulations based on GEANT 4 models.
Fundamental interactions Astbury, A; Campbel, B. A; Khanna, F. C ...
2002., 2002, 20020325
eBook
The Lake Louise Winter Institute is held annually to explore recent trends in physics. The proceedings contain pedagogical and review lectures by invited experts and contributed presentations by ...participants.
The Lake Louise Winter Institute is held annually to explore recent trends in physics in an informal setting. Pedagogical and review lectures are presented by invited experts. A topical workshop is ...held in conjunction with the Institute, with contributed presentations by participants. It concentrates on areas related to the invited lectures. Participants are encouraged to present material that includes recent developments in experimental and theoretical physics.
The Lake Louise Winter Institute is held annually to explore recent trends in high energy physics in an informal setting. Pedagogical and review lectures are presented by invited experts. A topical ...workshop is held in conjunction with the Institute, with presentations by participants.
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