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.
Evidence for B¯s0→Λc+Λ¯π Solovieva, E.; Chistov, R.; Adachi, I. ...
Physics letters. B,
10/2013, Volume:
726, Issue:
1-3
Journal Article
Peer reviewed
Using 121.4 fb−1 of data collected with the Belle detector at the ϒ(5S) resonance at the KEKB asymmetric-energy e+e− collider, we report evidence for the B¯s0→Λc+Λ¯π− decay mode with a measured ...branching fraction (3.6±1.1stat.−0.5+0.3syst.±0.9Λc+±0.7NB¯s0)×10−4 and a significance of 4.4 standard deviations. This is the first evidence for a baryonic Bs0 decay.
The muon-proton and muon-deuteron inclusive deep inelastic scattering cross sections were measured in the kinematic range 0.002 < x < 0.60 and 0.5 < Q(2) < 75 GeV2 at incident muon ...energies of 90, 120, 200 and 280 GeV. These results are based on the full
A measurement of the proton spin structure function g1p(x,Q{sup 2}) in deep-inelastic scattering is presented. The data were taken with the 27.6 GeV longitudinally polarised positron beam at HERA ...incident on a longitudinally polarised pure hydrogen gas target internal to the storage ring. The kinematic range is 0.021<x<0.85 and 0.8 GeV{sup 2}<Q{sup 2}<20 GeV{sup 2}.
The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of DESY HERA. The use of a tensor-polarized deuteron gas target with only a ...negligible residual vector polarization enabled the first measurement of the tensor asymmetry A{sub zz}{sup d} and the tensor structure function b{sub 1}{sup d} for average values of the Bjorken variable 0.01< <0.45 and of the negative of the squared four-momentum transfer 0.5 GeV{sup 2}<<Q{sup 2}><5 GeV{sup 2}. The quantities A{sub zz}{sup d} and b{sub 1}{sup d} are found to be nonzero. The rise of b{sub 1}{sup d} for decreasing values of x can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering.
The spin structure of the nucleon is studied with deep inelastic scattering by HERMES. The electron (positron) beam at 27.6 GeV, polarized internal gas targets, and wide acceptance magnetic ...spectrometer with a ring imaging Cherenkov counter for the particle identification are the important ingredients of the experiment. The observation of significant azimuthal asymmetry in pion productions is reported. The measurement of the quark transverse spin distribution
h
1(
x) which is underway is discussed.
Results are presented for F-2(d)/F-2(p) and R(d) - R(p) from simultaneous measurements of deep inelastic muon scattering on hydrogen and deuterium targets, at 90, 120, 200 and 280 GeV. The difference ...R(d) - R(p), determined in the range 0.002 < x < 0.4 at
We present a re-evaluation of the structure function ratios F-2(He)/F-2(D), F-2(C)/F-2(D) and F-2(Ca)/F-2(D) measured in deep inelastic muon-nucleus scattering at an incident muon momentum of 200 ...GeV. We also present the ratios F-2(C)/F-2(Li), F-2(Ca)/F-2
The Q(2) dependence of the structure function ratio F-2(Sn)/F-2(C) for 0.01 < x < 0.75 and 1 < Q(2) < 140 GeV2 is reported. For x < 0.1 the size of shadowing decreases linearly with In ...Q(2) and the maximum rate is about 0.04 at x = 0.01. The rate decrease
We present the structure function ratios F-2(Li)/F-2(D) and F-2(C)/F-2(D) measured in deep inelastic muon-nucleus scattering at a nominal incident muon energy of 200 GeV. The kinematic range 10(-4) ...< x < 0.7 and 0.01 < Q(2) < 70 GeV2 is covered. For value
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