Lauscher, P.
Deep Inelastic Scattering
[1.0, 2.0]
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Separated structure functions for the exclusive electroproduction of K+ Lambda and K+ Sigma0 final states.

The CLAS collaboration Ambrozewicz, P. ; Carman, D.S. ; Feuerbach, R.J. ; et al.
Phys.Rev.C 75 (2007) 045203, 2007.
Inspire Record 732363 DOI 10.17182/hepdata.4994

We report measurements of the exclusive electroproduction of $K^+\Lambda$ and $K^+\Sigma^0$ final states from a proton target using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The separated structure functions $\sigma_T$, $\sigma_L$, $\sigma_{TT}$, and $\sigma_{LT}$ were extracted from the $\Phi$- and $\epsilon$-dependent differential cross sections taken with electron beam energies of 2.567, 4.056, and 4.247 GeV. This analysis represents the first $\sigma_L/\sigma_T$ separation with the CLAS detector, and the first measurement of the kaon electroproduction structure functions away from parallel kinematics. The data span a broad range of momentum transfers from $0.5\leq Q^2\leq 2.8$ GeV$^2$ and invariant energy from $1.6\leq W\leq 2.4$ GeV, while spanning nearly the full center-of-mass angular range of the kaon. The separated structure functions reveal clear differences between the production dynamics for the $\Lambda$ and $\Sigma^0$ hyperons. These results provide an unprecedented data sample with which to constrain current and future models for the associated production of strangeness, which will allow for a better understanding of the underlying resonant and non-resonant contributions to hyperon production.

531 data tables
Table 1

Cross sections for incident energy 2.567 GeV for the Q**2 range 0.5 to 0.8 GeV**2 and W range 1.6 to 1.7 GeV.

Table 2

Cross sections for incident energy 2.567 GeV for the Q**2 range 0.5 to 0.8 GeV**2 and W range 1.70 to 1.75 GeV.

Table 3

Cross sections for incident energy 2.567 GeV for the Q**2 range 0.5 to 0.8 GeV**2 and W range 1.75 to 1.80 GeV.

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Measurement of the $x$- and $Q^2$-Dependence of the Asymmetry $A_1$ on the Nucleon

The CLAS collaboration Dharmawardane, K.V. ; Kuhn, S.E. ; Bosted, Peter E. ; et al.
Phys.Lett.B 641 (2006) 11-17, 2006.
Inspire Record 717523 DOI 10.17182/hepdata.6726

We report results for the virtual photon asymmetry $A_1$ on the nucleon from new Jefferson Lab measurements. The experiment, which used the CEBAF Large Acceptance Spectrometer and longitudinally polarized proton ($^{15}$NH$_3$) and deuteron ($^{15}$ND$_3$) targets, collected data with a longitudinally polarized electron beam at energies between 1.6 GeV and 5.7 GeV. In the present paper, we concentrate on our results for $A_1(x,Q^2)$ and the related ratio $g_1/F_1(x,Q^2)$ in the resonance and the deep inelastic regions for our lowest and highest beam energies, covering a range in momentum transfer $Q^2$ from 0.05 to 5.0 GeV$^2$ and in final-state invariant mass $W$ up to about 3 GeV. Our data show detailed structure in the resonance region, which leads to a strong $Q^2$--dependence of $A_1(x,Q^2)$ for $W$ below 2 GeV. At higher $W$, a smooth approach to the scaling limit, established by earlier experiments, can be seen, but $A_1(x,Q^2)$ is not strictly $Q^2$--independent. We add significantly to the world data set at high $x$, up to $x = 0.6$. Our data exceed the SU(6)-symmetric quark model expectation for both the proton and the deuteron while being consistent with a negative $d$-quark polarization up to our highest $x$. This data setshould improve next-to-leading order (NLO) pQCD fits of the parton polarization distributions.

306 data tables
Table 1

A1 and g1/F1 for the P target at incident energy 1.6000 GeV and W = 1.1300 GeV.

Table 2

A1 and g1/F1 for the P target at incident energy 1.6000 GeV and W = 1.1500 GeV.

Table 3

A1 and g1/F1 for the P target at incident energy 1.6000 GeV and W = 1.1700 GeV.

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A kinematically complete measurement of the proton structure function F2 in the resonance region and evaluation of its moments.

The CLAS collaboration Osipenko, M. ; Ricco, G. ; Taiuti, M. ; et al.
Phys.Rev.D 67 (2003) 092001, 2003.
Inspire Record 612145 DOI 10.17182/hepdata.12253

We measured the inclusive electron-proton cross section in the nucleon resonance region (W < 2.5 GeV) at momentum transfers Q**2 below 4.5 (GeV/c)**2 with the CLAS detector. The large acceptance of CLAS allowed for the first time the measurement of the cross section in a large, contiguous two-dimensional range of Q**2 and x, making it possible to perform an integration of the data at fixed Q**2 over the whole significant x-interval. From these data we extracted the structure function F2 and, by including other world data, we studied the Q**2 evolution of its moments, Mn(Q**2), in order to estimate higher twist contributions. The small statistical and systematic uncertainties of the CLAS data allow a precise extraction of the higher twists and demand significant improvements in theoretical predictions for a meaningful comparison with new experimental results.

46 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Measurement of the Antilambda polarization in nu/mu charged current interactions in the NOMAD experiment.

The NOMAD collaboration Astier, P. ; Autiero, D. ; Baldisseri, A. ; et al.
Nucl.Phys.B 605 (2001) 3-14, 2001.
Inspire Record 554759 DOI 10.17182/hepdata.48928

We present a measurement of the polarization of Antilambda hyperons produced in nu_mu charged current interactions. The full data sample from the NOMAD experiment has been analyzed using the same V0 identification procedure and analysis method reported in a previous paper for the case of Lambda hyperons. The Antilambda polarization has been measured for the first time in a neutrino experiment. The polarization vector is found to be compatible with zero.

2 data tables
Table 1

Lambdabar polarization in regions of Feynman X (XL).

Table 2

Lambdabar polarization in regions of the Bjorken scaling variable X.


Precise pion electroproduction in the p (e, e-prime pi+) n reaction at W = 1125-MeV

Blomqvist, K.I. ; Boeglin, W.U. ; Böhm, R. ; et al.
Z.Phys.A 353 (1996) 415-421, 1996.
Inspire Record 428951 DOI 10.17182/hepdata.16502

The reactione+p →> e+π++n at c.m. energyW=1125MeV and momentum transfer Q2=0.117GeV2/c2 has been measured. The transverse and longitudinal structure functions have been separated by varying the polarization of the virtual photon (Rosenbluth plot) with a 3 to 4% error. In addition the longitudinal-transverse interference term has been determined measuring the right-left asymmetry with an accuracy of 3%. The experimental data are compared to model calculations, and the sensitivity of the results to the axial and pion formfactors is discussed.

6 data tables
Table 1

Angle PHI(P=4) is the angle between the scattering plane (defined by 1 and 3 particles) and the reaction plane (defined by 4 and 5 particles).

Table 2

Angle PHI(P=4) is the angle between the scattering plane (defined by 1 and 3 particles) and the reaction plane (defined by 4 and 5 particles).

Table 3

Angle PHI(P=4) is the angle between the scattering plane (defined by 1 and 3 particles) and the reaction plane (defined by 4 and 5 particles).

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The Cross-section Ratio $\sigma(\nu n)/\sigma(\nu p)$ for Charged Current and Neutral Current Interactions Below 10-{GeV}

Jacques, P.F. ; Kalelkar, M. ; Miller, P.A. ; et al.
Phys.Rev.D 24 (1981) 1067-1070, 1981.
Inspire Record 165487 DOI 10.17182/hepdata.24072

We have measured the cross-section ratio σ(νn)σ(νp) for both charged-current and neutral-current interactions at low energy. The experiment used the wide-band neutrino beam at Brookhaven National Laboratory. The detector was the 7-foot bubble chamber filled with a 62% neon-hydrogen mixture. For charged-current events we find that the ratio reaches an asymptotic value of 1.80±0.19 for neutrino energies above 1 GeV. For neutral-current events we measure the ratio to be 1.07±0.24. Both of these results are in agreement with the quark model.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Study of Low-energy Anti-neutrino Interactions on Protons

Fanourakis, G. ; Resvanis, L.K. ; Grammatikakis, G. ; et al.
Phys.Rev.D 21 (1980) 562, 1980.
Inspire Record 9011 DOI 10.17182/hepdata.24171

We present a study of antineutrino interactions in hydrogen obtained in a 138000-picture run at the BNL 7-ft bubble chamber. The antineutrino beam had an energy distribution that peaked at ∼1.1 GeV. The cross section measured for charged-current interactions is σ(ν¯p→μ++anything)=(0.32±0.08)×10−38×[Eν¯ (GeV)] cm2. The neutral-current cross section is σ(ν¯p→ν¯pπ+π−)=5.5−2.6+4.4×10−40 cm2. The ratio of strangeness-changing to non-strangeness-changing charged currents is Rs=0.06−0.05+0.13. An upper limit determined for charm production is σc<3.8×10−40 cm2 at the 90% confidence level. From the momentum-transfer distribution we measure average Q2 for inelastic charged-current events with energy greater than 2 GeV, 〈Q2〉=(0.10±0.03)[Eν¯ (GeV)]+(0.10±0.09) (GeV/c)2. Using a maximum-likelihood method we determine from the quasielastic events ν¯p→μ+n an axial-vector mass MA=0.9−0.3+0.4 GeV/c2.

1 data table
Table 1

Measured charged current total cross section.


Electroproduction of $\rho^0$ Mesons

Cohen, I. ; Erickson, R. ; Messing, F. ; et al.
Phys.Rev.D 25 (1982) 634, 1982.
Inspire Record 152921 DOI 10.17182/hepdata.47139

Cross sections for ρ0 electroproduction measured in a streamer-chamber experiment are separated into elastic (ep→epρ0) and inelastic production channels. For the elastic channel, the total cross section and t dependence are presented. For the inelastic channel (1σ)dσdz, (1σ)dσdpT2, and a density matrix element are shown and compared to quark-parton-model predictions. The ratio of ρ0 to direct π0 production is found to be 2.0±0.5±0.3, where the first error is statistical, and the second error is systematic.

8 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Study of Neutrino Interactions in Hydrogen and Deuterium: Inelastic Charged Current Reactions

Barish, S.J. ; Derrick, M. ; Dombeck, T. ; et al.
Phys.Rev.D 19 (1979) 2521, 1979.
Inspire Record 7237 DOI 10.17182/hepdata.24295

This paper gives the results of a study of inelastic charged-current interactions of muon-type neutrinos with hydrogen and deuterium targets using the Argonne 12-foot bubble chamber. We discuss in detail the separation of the events from background. For the single-pion production reactions νp→μ−pπ+, νn→μ−nπ+, and νn→μ−pπ0, energy-dependent cross sections, differential cross sections, invariant-mass distributions, and the Δ++(1236) decay angular distribution are presented. These data are also used to study the isospin properties of the πN system. Comparisons of the data with models of single-pion production are made, and a direct test of partial conservation of the axial-vector current is discussed. Cross sections and invariant-mass distributions are given for the reactions in which more than one pion is produced. Ten events of strange-particle production were found, and the properties of these events are discussed. The energy dependence of the total νp and νn cross sections from threshold to 6 GeV was determined, and the σ(νn)σ(νp) ratio measured. This ratio and the inclusive x and y distributions rapidly approach the scaling distributions expected from the quark-parton model.

1 data table
Table 1

Measured charged current total cross section.


Inclusive Neutrino p and Neutrino n Charged-Current Neutrino Reactions Below 6-GeV

Barish, S.J. ; Derrick, M. ; Dombeck, T. ; et al.
Phys.Lett.B 66 (1977) 291-294, 1977.
Inspire Record 4240 DOI 10.17182/hepdata.27596

Results are presented of a study of inclusive ηp and ηn interactions from threshold to 6 GeV. The data show a rapid approach to the distributions expected in the naive quark-parton model. The charged-current η deuteron total cross section is fit by the expression σ T ( η d) = (0.76 ± 0.03) × 10 −38 E η cm 2 per GeV per nucleon. For E η > 1.5 GeV, we measure σ T ( η n)/ σ T ( η p) = (2.02 ± 0.23). The distributions in the scaling variables x and y are given and discussed.

1 data table
Table 1

Measured charged current total cross section.