Precision measurement of the proton and deuteron spin structure functions g2 and asymmetries A(2).

The E155 collaboration Anthony, P.L. ; Arnold, R.G. ; Averett, T. ; et al.
Phys.Lett.B 553 (2003) 18-24, 2003.
Inspire Record 585675 DOI 10.17182/hepdata.27033

We have measured the spin structure functions g2p and g2d and the virtual photon asymmetries A2p and A2d over the kinematic range 0.02 < x < 0.8 and 0.7 < Q^2 < 20 GeV^2 by scattering 29.1 and 32.3 GeV longitudinally polarized electrons from transversely polarized NH3 and 6LiD targets. Our measured g2 approximately follows the twist-2 Wandzura-Wilczek calculation. The twist-3 reduced matrix elements d2p and d2n are less than two standard deviations from zero. The data are inconsistent with the Burkhardt-Cottingham sum rule if there is no pathological behavior as x->0. The Efremov-Leader-Teryaev integral is consistent with zero within our measured kinematic range. The absolute value of A2 is significantly smaller than the sqrt[R(1+A1)/2] limit.

7 data tables

Values of A2 and X*G2 from proton and deuterium target data at mean electron scattering angle of 2.75 degrees and incident energy 29.1 GeV. Errors shown are statistical only.

Values of A2 and X*G2 from proton and deuterium target data at mean electron scattering angle of 5.5 degrees and incident energy 29.1 GeV. Errors shown are statistical only.

Values of A2 and X*G2 from proton and deuterium target data at mean electron scattering angle of 10.5 degrees and incident energy 29.1 GeV. Errors shown are statistical only.

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Spectra and correlations of Lambda and Lambda produced in 340-GeV/c Sigma -+C and 260-GeV/c n+C interactions

Adamovich, M.I. ; Alexandrov, Yu.A. ; Baranov, S.P. ; et al.
Phys.Rev.C 65 (2002) 042202, 2002.
Inspire Record 585235 DOI 10.17182/hepdata.25354

We have measured the production of strange baryons and antibaryons in 340-GeV/c Σ−+C and 260-GeV/c n+C interactions. The single xF distributions show the expected leading particle effect, and the single pt2 distributions show a distinct nonthermal behavior. The xF distributions of Λ-Λ pairs indicate two different phase space distributions for the two coincident baryons. On the other hand two Λ¯’s show identical distributions. Momentum conservation during the formation process may represent a significant source for the observed behavior.

4 data tables

Total inclusive LAMBDA and LAMBDABAR production cross sections for the SIGMA- beam on the Carbon target.

Total inclusive LAMBDA and LAMBDABAR production cross sections for the Neutron beam on the Carbon target.

Total inclusive LAMBDA LAMBDA and LAMBDABAR LAMBDABAR pair production crosssections for the SIGMA- beam on the Carbon target.

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The Ratio, rho, of the real to the imaginary part of the anti-p p forward elastic scattering amplitude at s**(1/2) = 1.8-TeV

The E-811 collaboration Avila, C ; Baker, W.F ; DeSalvo, R ; et al.
Phys.Lett.B 537 (2002) 41-44, 2002.
Inspire Record 586322 DOI 10.17182/hepdata.42841

We have measured $\rho$ , the ratio of the real to the imaginary part of the $p \bar{p}$ forward elastic scattering amplitude, at $\sqrt{s}$ = 1.8  TeV. Our result is $\rho$ = 0.132 $\pm$ 0.056; this can be combined with a previous measurement at the same energy to give $\rho$ = 0.135 $\pm$ 0.044.

2 data tables

Measured value of the total cross section.

The measured value of the ratio of real to imaginary part of the forward scattering amplitude.


Compton Scattering from the Deuteron and Extracted Neutron Polarizabilities

Lundin, M. ; Adler, J.O. ; Boland, M. ; et al.
Phys.Rev.Lett. 90 (2003) 192501, 2003.
Inspire Record 586101 DOI 10.17182/hepdata.31727

Differential cross sections for Compton scattering from the deuteron were measured at MAX-lab for incident photon energies of 55 MeV and 66 MeV at nominal laboratory angles of $45^\circ$, $125^\circ$, and $135^\circ$. Tagged photons were scattered from liquid deuterium and detected in three NaI spectrometers. By comparing the data with theoretical calculations in the framework of a one-boson-exchange potential model, the sum and difference of the isospin-averaged nucleon polarizabilities, $\alpha_N + \beta_N = 17.4 \pm 3.7$ and $\alpha_N - \beta_N = 6.4 \pm 2.4$ (in units of $10^{-4}$ fm$^3$), have been determined. By combining the latter with the global-averaged value for $\alpha_p - \beta_p$ and using the predictions of the Baldin sum rule for the sum of the nucleon polarizabilities, we have obtained values for the neutron electric and magnetic polarizabilities of $\alpha_n= 8.8 \pm 2.4$(total) $\pm 3.0$(model) and $\beta_n = 6.5 \mp 2.4$(total) $\mp 3.0$(model), respectively.

6 data tables

Centre of mass differential cross sections for deuteron compton scattering at incident photon energy 54.6 MeV.

Centre of mass differential cross sections for deuteron compton scattering at incident photon energy 54.9 MeV.

Centre of mass differential cross sections for deuteron compton scattering at incident photon energy 55.9 MeV.

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Production of pi0 and eta mesons at large transverse momenta in pp and p Be interactions at 530-GeV/c and 800-GeV/c

The Fermilab E706 collaboration Apanasevich, L. ; Bacigalupi, J. ; Baker, W. ; et al.
Phys.Rev.D 68 (2003) 052001, 2003.
Inspire Record 585866 DOI 10.17182/hepdata.11186

We present results on the production of high transverse momentum pizero and eta mesons in pp and pBe interactions at 530 and 800 GeV/c. The data span the kinematic ranges: 1 < p_T < 10 GeV/c in transverse momentum and 1.5 units in rapidity. The inclusive pizero cross sections are compared with next-to-leading order QCD calculations and to expectations based on a phenomenological parton-k_T model.

21 data tables

Invariant differetrial cross sections/nucleon for the inclusive reaction p Be --> pi0 X at 530 and 800 GEV, averaged over the c.m. rapidity interval -0.75 to 0.75 and -1.0 to 0.5 respectively.

Invariant differetrial cross sections/nucleon for the inclusive reaction p p --> pi0 X at 530 and 800 GEV, averaged over the c.m. rapidity interval -0.75 to 0.75 and -1.0 to 0.5 respectively.

The averaged invariant differential cross section/nucleon as a function of rapidity in the PT intervals 1.0-1.5, 1.5-2.0 and 2.0-2.5 GeV for the inclusive reaction p BE --> pi0 X at 530 and 800 GeV GeV.

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Measurement of the Lambda and Antilambda particles in Au + Au collisions at s(NN)**(1/2) = 130-GeV.

The PHENIX collaboration Adcox, K. ; Adler, S.S. ; Ajitanand, N.N. ; et al.
Phys.Rev.Lett. 89 (2002) 092302, 2002.
Inspire Record 585561 DOI 10.17182/hepdata.139716

We present results on the measurement of lambda and lambda^bar production in Au+Au collisions at sqrt(s_NN)=130 GeV with the PHENIX detector at RHIC. The transverse momentum spectra were measured for minimum bias and for the 5% most central events. The lambda^bar/lambda ratios are constant as a function of p_T and the number of participants. The measured net lambda density is significantly larger than predicted by models based on hadronic strings (e.g. HIJING) but in approximate agreement with models which include the gluon junction mechanism.

9 data tables

Transverse momentum spectra of $\Lambda$ and $\bar{\Lambda}$ for minimum-bias and for the $5\%$ most central events.

The ratio of $\bar{\Lambda}$/$\Lambda$ as a function of $p_T$.

The ratio of $\bar{\Lambda}$/$\Lambda$ as a function of the number of participants.

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Flow measurements via two-particle azimuthal correlations in Au + Au collisions at s(NN)**(1/2) = 130-GeV.

The PHENIX collaboration Adcox, K. ; Adler, S.S. ; Ajitanand, N.N. ; et al.
Phys.Rev.Lett. 89 (2002) 212301, 2002.
Inspire Record 585347 DOI 10.17182/hepdata.141931

Two particle azimuthal correlation functions are presented for charged hadrons produced in Au + Au collisions at RHIC sqrt(s_NN) = 130 GeV. The measurements permit determination of elliptic flow without event-by-event estimation of the reaction plane. The extracted elliptic flow values v_2 show significant sensitivity to both the collision centrality and the transverse momenta of emitted hadrons, suggesting rapid thermalization and relatively strong velocity fields. When scaled by the eccentricity of the collision zone, epsilon, the scaled elliptic flow shows little or no dependence on centrality for charged hadrons with relatively low p_T. A breakdown of this epsilon scaling is observed for charged hadrons with p_T > 1.0 GeV/c for the most central collisions.

8 data tables

Azimuthal correlation functions for charged hadrons as a function of centrality and $p_T$ selection. The solid curves represent Fourier fits following Eq. (2). Error bars are statistical only.

$v_2$ vs. centrality for several $p_T$ selections. [F] and [A] indicate results obtained with the fixed-$p_T$ and assorted-$p_T$ methods respectively. Systematic errors are estimated to be $\sim 5$%; they are dominated by the normalization of the correction function for real tracks. For the centrality range 0-5%, the data points are statistically uncertain and the points are omitted.

$v_2$ vs. centrality for several $p_T$ selections. [F] and [A] indicate results obtained with the fixed-$p_T$ and assorted-$p_T$ methods respectively. Systematic errors are estimated to be $\sim 5$%; they are dominated by the normalization of the correction function for real tracks. For the centrality range 0-5%, the data points are statistically uncertain and the points are omitted.

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Measurements of charged current reactions of nu/mu on C-12.

The LSND collaboration Auerbach, L.B. ; Burman, R.L. ; Caldwell, D.O. ; et al.
Phys.Rev.C 66 (2002) 015501, 2002.
Inspire Record 584364 DOI 10.17182/hepdata.25353

Charged current scattering of \nu_\mu on ^{12}C has been studied using a \pi^+ decay-in-flight \nu_\mu beam at the Los Alamos Neutron Science Center. A sample of 66.9+-9.1 events satisfying criteria for the exclusive reaction ^{12}C(\nu_\mu,\mu^-)^{12}N_{g.s.} was obtained using a large liquid scintillator neutrino detector. The observed flux-averaged cross section (5.6+-0.8+-1.0) x 10^{-41} cm^2 agrees well with reliable theoretical expectations. A measurement was also obtained for the inclusive cross section to all accessible ^{12}N states ^{12}C(\nu_\mu,\mu^-)X. This flux-averaged cross section is (10.6+-0.3+-1.8) x 10^{-40} cm^2 which is lower than present theoretical calculations.

1 data table

Measured Quasi-Elastic total cross section.


A measurement of the t dependence of the helicity structure of diffractive rho meson electroproduction at HERA.

The H1 collaboration Adloff, C. ; Andreev, V. ; Andrieu, B. ; et al.
Phys.Lett.B 539 (2002) 25-39, 2002.
Inspire Record 584099 DOI 10.17182/hepdata.46666

The helicity structure of the diffractive electroproduction of rho mesons, e + p -> e + rho + Y, is studied in a previously unexplored region of large four-momentum transfer squared at the proton vertex, t: 0 < t' < 3 GeV^2, where t' = |t| - |t|_min. The data used are collected with the H1 detector at HERA in the kinematic domain 2.5 < Q^2 < 60 GeV^2, 40 < W < 120 GeV. No t dependence of the r^04_00 spin density matrix element is found. A significant t dependent helicity non-conservation from the virtual photon to the rho meson is observed for the spin density matrix element combinations r^5_00+2r^5_11 and r^1_00+2r^1_11. These t dependences are consistently described by a perturbative QCD model based on the exchange of two gluons.

1 data table

Measurements of the combinations of spin density matrices as a function of TP = |T| - |Tmin|, where |Tmin| is the minimal values of |T| kinematically required for the vector meson and the system X to aquire their effective mass through longitudinal momentum transfer.


Measurement of the Q**2 and energy dependence of diffractive interactions at HERA.

The ZEUS collaboration Chekanov, S. ; Krakauer, D. ; Magill, S. ; et al.
Eur.Phys.J.C 25 (2002) 169-187, 2002.
Inspire Record 584714 DOI 10.17182/hepdata.46612

Diffractive dissociation of virtual photons, gamma* p-->Xp, has been studied in ep interactions with the ZEUS detector at HERA using an integrated luminosity of approx. 10 pb^-1. The data cover photon virtualities 0.17 < Q^2< 0.70 GeV^2 and 3 < Q^2< 80 GeV^2 with 3<M_X<38 GeV, where M_X is the mass of the hadronic final state.

9 data tables

The double differential cross section d2sig/dmx/dt measured with the LPS method for the Q**2 range 0.17 to 0.70 GeV**2.

The double differential cross section d2sig/dmx/dt measured with the LPS method for the Q**2 range 3 to 9 GeV**2.

The double differential cross section d2sig/dmx/dt measured with the LPS method for the Q**2 range 9 to 80 GeV**2.

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