HEPData Search

Showing 10 of 37 results

Proton polarization in deuteron photodisintegration in the Δ(1232)-resonance region

Zybalov, A.A. ; Konovalov, O.G. ; Marekhin, S.V. ; et al.

Nucl.Phys.A 533 (1991) 642-650, 1991.

Inspire Record 1392876 DOI 10.17182/hepdata.36724

We report the results from measurements of proton polarization P , in the γ +D→p+n reaction at photon energies ranging from 200 to 350 MeV. The data obtained are compared with the measured analysing power A , of the reverse reaction and with model calculations. The assumption of the dominant contribution of isobar configurations in this region is on the whole confirmed by the present proton polarization measurements.

5 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…

Polarization of protons in the reactions $\gamma^{3,4}$He$\rightarrow\overrightarrow{p}X$ and the quasideuteron model

Zybalov, A.A. ; Karasev, S.P. ; Konovalov, O.G. ; et al.

Sov.J.Nucl.Phys. 47 (1988) 955-956, 1988.

Inspire Record 1392524 DOI 10.17182/hepdata.17410

None

1 data table

Table 1

No description provided.

Exclusive rho^0 production in deep inelastic scattering at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.

PMC Phys.A 1 (2007) 6, 2007.

Inspire Record 757991 DOI 10.17182/hepdata.54963

Exclusive rho^0 electroproduction at HERA has been studied with the ZEUS detector using 120 pb^{-1} of integrated luminosity collected during 1996-2000. The analysis was carried out in the kinematic range of photon virtuality 2 < Q^2 < 160 GeV$^2, and gamma^* p centre-of-mass energy 32 < W < 180 GeV. The results include the Q^2 and W dependence of the gamma^* p --> rho^0 p cross section and the distribution of the squared-four-momentum transfer to the proton. The helicity analysis of the decay-matrix elements of the rho^0 was used to study the ratio of the gamma^* p cross section for longitudinal and transverse photon as a function of Q^2 and W. Finally, an effective Pomeron trajectory was extracted. The results are compared to various theoretical predictions.

30 data tables

Table 1

Measurement of the spin density matrix element r_04_00 as a function of Q**2.

Table 2

Measurement of the spin density matrix element RE(r_04_10) as a function of Q**2.

Table 3

Measurement of the spin density matrix element r_04_1-1 as a function of Q**2.

More…

Exclusive electroproduction of J/psi mesons at HERA.

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Krakauer, D. ; et al.

Nucl.Phys.B 695 (2004) 3-37, 2004.

Inspire Record 647777 DOI 10.17182/hepdata.46277

The exclusive electroproduction of J/psi mesons, ep->epJ/psi, has been studied with the ZEUS detector at HERA for virtualities of the exchanged photon in the ranges 0.15<Q^2<0.8 GeV^2 and 2<Q^2<100 GeV^2 using integrated luminosities of 69 pb^-1 and 83 pb^-1, respectively.The photon-proton centre-of-mass energy was in the range 30<W<220 GeV and the squared four-momentum transfer at the proton vertex |t|<1.The cross sections and decay angular distributions are presented as functions of Q^2, W and t. The effective parameters of the Pomeron trajectory are in agreement with those found in J/psi photoproduction. The spin-density matrix elements, calculated from the decay angular distributions, are consistent with the hypothesis of s-channel helicity conservation. The ratio of the longitudinal to transverse cross sections, sigma_L/sigma_T, grows with Q^2, whilst no dependence on W or t is observed. The results are in agreement with perturbative QCD calculations and exhibit a strong sensitivity to the gluon distribution in the proton.

20 data tables

Table 1

Cross sections for exclusive J/PSI production as a function of W in the Q**2 region 0.15 to 0.18 GeV**2.

Table 2

Cross sections for exclusive J/PSI production as a function of W in the Q**2 region 2 to 5 GeV**2.

Table 3

Cross sections for exclusive J/PSI production as a function of W in the Q**2 region 5 to 10 GeV**2.

More…

Production asymmetry measurement of high x(T) hadrons in p(pol.) p collisions at 40-GeV.

Abramov, V.V. ; Dyshkant, A.S. ; Evdokimov, V.N. ; et al.

Nucl.Phys.B 492 (1997) 3-17, 1997.

Inspire Record 429347 DOI 10.17182/hepdata.40519

Single-spin asymmetries for hadrons have been measured in collisions of transversely-polarized 40 GeV/c proton beam with an unpolarized liquid hydrogen target. The asymmetries were measured for pi+-, K+-, protons and antiprotons, produced in the central region (0.02 < Xf < 0.10 and 0.7 < Pt < 3.4 GeV/c). Asymmetries for pi+-, K+- and antiprotons show within measurement errors the linear dependence on Xt and change a sign near 0.37. For protons negative asymmetry, independent of Xt has been found. The results are compared with those of other experiments and SU(6) model predictions.

3 data tables

Table 1

Table 2

Table 3

Polarization of cumulative protons in the reaction gamma A --> p X.

Avakyan, R.O. ; Avakian, E.O. ; Avdalyan, G.A. ; et al.

Sov.J.Nucl.Phys. 51 (1990) 999-1000, 1990.

Inspire Record 306076 DOI 10.17182/hepdata.17310

None

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

New Measurement of the Production Polarization and Magnetic Moment of the Cascade Minus Hyperon

Trost, L.H. ; McCliment, E.R. ; Newsom, C.R. ; et al.

Phys.Rev.D 40 (1989) 1703, 1989.

Inspire Record 280604 DOI 10.17182/hepdata.23053

We have measured the production polarization and magnetic moment of a sample of 89×103Ξ− hyperons produced in the inclusive reaction p(400 GeV/c)+Cu→Ξ−+X. The weighted average of the polarization is -0.070±0.008±0.010 at a pt of 0.63 GeV/c. The Ξ−'s magnetic moment yields the value μΞ=−0.661±0.036±0.036 nuclear magnetons. The first error is statistical, the second systematic.

1 data table

Table 1

No description provided.