Inclusive double-helicity asymmetries in neutral pion and eta meson production in $\vec{p}+\vec{p}$ collisions at $\sqrt{s}=200$ GeV

The PHENIX collaboration Adare, A. ; Aidala, C. ; Ajitanand, N.N. ; et al.
Phys.Rev.D 90 (2014) 012007, 2014.
Inspire Record 1282448 DOI 10.17182/hepdata.64716

Results are presented from data recorded in 2009 by the PHENIX experiment at the Relativistic Heavy Ion Collider for the double-longitudinal spin asymmetry, $A_{LL}$, for $\pi^0$ and $\eta$ production in $\sqrt{s} = 200$ GeV polarized $p$$+$$p$ collisions. Comparison of the $\pi^0$ results with different theory expectations based on fits of other published data showed a preference for small positive values of gluon polarization, $\Delta G$, in the proton in the probed Bjorken $x$ range. The effect of adding the new 2009 \pz data to a recent global analysis of polarized scattering data is also shown, resulting in a best fit value $\Delta G^{[0.05,0.2]}_{\mbox{DSSV}} = 0.06^{+0.11}_{-0.15}$ in the range $0.05<x<0.2$, with the uncertainty at $\Delta \chi^2 = 9$ when considering only statistical experimental uncertainties. Shifting the PHENIX data points by their systematic uncertainty leads to a variation of the best-fit value of $\Delta G^{[0.05,0.2]}_{\mbox{DSSV}}$ between $0.02$ and $0.12$, demonstrating the need for full treatment of the experimental systematic uncertainties in future global analyses.

9 data tables match query

PI0 ASYM(LL) measurements from 2005.

PI0 ASYM(LL) measurements from 2006.

PI0 ASYM(LL) measurements from 2009.

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Precision neutral current asymmetry parameter measurements from the tau polarization at LEP.

The OPAL collaboration Abbiendi, G. ; Ainsley, C. ; Akesson, P.F. ; et al.
Eur.Phys.J.C 21 (2001) 1-21, 2001.
Inspire Record 554583 DOI 10.17182/hepdata.49765

Measurements of the tau lepton polarization and forward-backward polarization asymmetry near the Z resonance using the OPAL detector are described. The measurements are based on analyses of tau -> e nu_e nu_tau, tau -> mu nu_mu nu_tau, tau -> pi nu_tau, tau -> rho nu_tau and tau -> a1 nu_tau decays from a sample of 144810 e+e- -> tau+ tau- candidates corresponding to an integrated luminosity of 151 pb-1. Assuming that the tau lepton decays according to V-A theory, we measure the average tau polarization near Ecm = MZ to be <Ptau> = (-14.10 +/- 0.73 +/- 0.55)% and the tau polarization forward-backward asymmetry to be Afb = (-10.55 +/- 0.76 +/- 0.25)%, where the first error is statistical and the second systematic. Taking into account the small effects of the photon propagator, photon-Z interference and photonic radiative corrections, these results can be expressed in terms of the lepton neutral current asymmetry parameters: Atau = 0.1456 +/- 0.0076 +/- 0.0057, Ae = 0.1454 +/- 0.0108 +/- 0.0036. These measurements are consistent with the hypothesis of lepton universality and combine to give Al = 0.1455 +/- 0.0073. Within the context of the Standard Model this combined result corresponds to sin^2(theta)(lept,effective) = 0.23172 +/- 0.00092. Combing these results with those from the other OPAL neutral current measurements yields a value of sin^2(theta)(lept,effective) = 0.23211 +/- 0.00068.

1 data table match query

No description provided.


W boson polarisation at LEP2.

The OPAL collaboration Abbiendi, G. ; Ainsley, C. ; Akesson, P.F. ; et al.
Phys.Lett.B 585 (2004) 223-236, 2004.
Inspire Record 635790 DOI 10.17182/hepdata.49660

Elements of the spin density matrix for W bosons in e+e- -> W+W- -> qqln events are measured from data recorded by the OPAL detector at LEP. This information is used calculate polarised differential cross-sections and to search for CP-violating effects. Results are presented for W bosons produced in e+e- collisions with centre-of-mass energies between 183 GeV and 209 GeV. The average fraction of W bosons that are longitudinally polarised is found to be (23.9 +- 2.1 +- 1.1)% compared to a Standard Model prediction of (23.9 +- 0.1)%. All results are consistent with CP conservation.

7 data tables match query

The fraction of longitudinal polarization for leptonically and hadronically decaying W bosons. The average values for all the centre of mass energies and for both lepton and hadron decay combined are also given.

The luminosity weighted average over all the centre of mass energies of the diagonal elements of the RHO++ and RHO-- SDM as a function of the cosine of the angle of the W- boson for the leptonic decay channel.

The luminosity weighted average over all the centre of mass energies of the diagonal element of the RHO00 SDM as a function of the cosine of the angle of the W- boson for both leptonic and hadronic decay channels, and combined.

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Measurements of Delta sigma-L (n p) between 500-MeV and 800-MeV

Beddo, M. ; Burleson, G. ; Faucett, J.A. ; et al.
Phys.Lett.B 258 (1991) 24-28, 1991.
Inspire Record 29058 DOI 10.17182/hepdata.51096

A measurement of Δσ L (np), the difference between neutron-proton total cross sections in pure longitudinal spin states, is described. Data were taken for five energies between 500 and 800 MeV, with statistical errors of ≈ 1.5 mb and an estimated normalization error of 6%. The data, combined with other results, show some evidence for an elastic I =0 spin-singlet resonance with mass ∼ 2213 MeV and width ∼ 74 MeV, or a coupled-triplet resonance with similar mass and width.

1 data table match query

SIG(C=PARALLEL)-SIG(C=ANTIPARALLEL) means the difference in the total crosssection with initial parallel and antiparallel longitudinal spin states. The I0 means I=0, these values were found using interpolated Delta(sigma(pp)) data.


Measurement of single spin asymmetry in eta meson production in p(pol.) p and in anti-p(pol.) p interactions in the beam fragmentation region at 200-GeV/c.

The Fermilab E704 collaboration Adams, D.L. ; Bonner, B.E. ; Corcoran, M.D. ; et al.
Nucl.Phys.B 510 (1998) 3-11, 1998.
Inspire Record 449811 DOI 10.17182/hepdata.51687

We present experimental results on measuring a single spin asymmetry in η-meson production in the interaction of transversely polarized protons and antiprotons at p lab = 200 GeV / c with a proton target in the region 0.2 < x F < 0.7 for p ↑ p , 0.3 < x F < 0.7 for p ̄ ↑p and 0.7 < p T < 2.0 GeV / c . A comparison of single spin asymmetries in π- and η-meson production is made.

2 data tables match query

The true asymmetry for ETA production in proton-proton collisions.

The true asymmetry for ETA production in antiproton-proton collisions.


Analyzing powers for the pi- p(pol.) --> pi0 n reaction across the Delta(1232) resonance.

Gaulard, C.V. ; Riedel, C.M. ; Comfort, Joseph R. ; et al.
Phys.Rev.C 60 (1999) 024604, 1999.
Inspire Record 483795 DOI 10.17182/hepdata.51678

High quality analyzing powers for the π−p→→π0n reaction have been obtained with a polarized proton target over a broad angular range at incident kinetic energies of 98.1, 138.8, 165.9, and 214.4 MeV. This experiment nearly doubled the existing πN single-charge-exchange database for energies ranging from 10 to 230 MeV, with 36 new analyzing powers. The Neutral Meson Spectrometer was used to detect the outgoing neutral pions. The data are well described by recent phase-shift analyses. When combined with high-precision and accurate cross section data at the same energies, the data can provide a good test of the degree of isospin breaking in the region of the Δ(1232) resonance. They will also be helpful for constraining the evaluation of the pion-nucleon σ term from the scattering amplitudes.

4 data tables match query

First error is total uncertainty.

First error is total uncertainty.

First error is total uncertainty.

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Measurement of eta photoproduction on the proton from threshold to 1500-MeV

The GRAAL collaboration Bartalini, O. ; Bellini, V. ; Bocquet, J.P. ; et al.
Eur.Phys.J.A 33 (2007) 169-184, 2007.
Inspire Record 755415 DOI 10.17182/hepdata.51526

Beam asymmetry and differential cross section for the reaction gamma+p->eta+p were measured from production threshold to 1500 MeV photon laboratory energy. The two dominant neutral decay modes of the eta meson, eta->2g and eta->3pi0, were analyzed. The full set of measurements is in good agreement with previously published results. Our data were compared with three models. They all fit satisfactorily the results but their respective resonance contributions are quite different. The possible photoexcitation of a narrow state N(1670) was investigated and no evidence was found.

45 data tables match query

Measured beam asymmetry at photon energy 724 MeV as a function of the ETA centre of mass angle.

Measured beam asymmetry at photon energy 761 MeV as a function of the ETA centre of mass angle.

Measured beam asymmetry at photon energy 810 MeV as a function of the ETA centre of mass angle.

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n p elastic analyzing power A(NO) and spin transfer K(NN)

McNaughton, M.W. ; Johnston, K. ; Swenson, D. ; et al.
Phys.Rev.C 48 (1993) 256-265, 1993.
Inspire Record 34401 DOI 10.17182/hepdata.51045

We have measured the analyzing power ANO and the spin transfer KNN for np-elastic scattering from about 60° to 170° c.m. at 485, 635, and 788 MeV. The new data clarify previous discrepancies and complete the first-order determination of nucleon-nucleon elastic scattering at these energies.

6 data tables match query

For definition of the POL(NAME=SPIN-TRANSFER) see text.

For definition of the POL(NAME=SPIN-TRANSFER) see text.

For definition of the POL(NAME=SPIN-TRANSFER) see text.

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Measurement of gamma p --> K+ Lambda and gamma p --> K+ Sigma0 at photon energies up to 2.6 GeV

Glander, K.H. ; Barth, J. ; Braun, W. ; et al.
Eur.Phys.J.A 19 (2004) 251-273, 2004.
Inspire Record 626695 DOI 10.17182/hepdata.51677

The reactions gamma p --> K+ Lambda and gamma p --> K+ Sigma0 were measured in the energy range from threshold up to a photon energy of 2.6 GeV. The data were taken with the SAPHIR detector at the electron stretcher facility, ELSA. Results on cross sections and hyperon polarizations are presented as a function of kaon production angle and photon energy. The total cross section for Lambda production rises steeply with energy close to threshold, whereas the Sigma0 cross section rises slowly to a maximum at about E_gamma = 1.45 GeV. Cross sections together with their angular decompositions into Legendre polynomials suggest contributions from resonance production for both reactions. In general, the induced polarization of Lambda has negative values in the kaon forward direction and positive values in the backward direction. The magnitude varies with energy. The polarization of Sigma0 follows a similar angular and energy dependence as that of Lambda, but with opposite sign.

24 data tables match query

Differential cross sections for the reaction GAMMA P --> K+ LAMBDA in the energy region 0.9 to 1.0 GeV.

Differential cross sections for the reaction GAMMA P --> K+ LAMBDA in the energy region 1.0 to 1.2 GeV.

Differential cross sections for the reaction GAMMA P --> K+ LAMBDA in the energy region 1.2 to 1.4 GeV.

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Measurement of the polarization in the decay B0 ---> J / psi K*0 in anti-p p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration
FERMILAB-CONF-94-127-E, 1994.
Inspire Record 374206 DOI 10.17182/hepdata.50099

None

1 data table match query

Here POL is longitudinal polarization Gl/G (see article for definition).


Measurement of the polarization parameter of the reactions pi- p ---> pi0 n and eta n at 5 and 8 gev/c

Bonamy, P. ; Borgeaud, P. ; Crozon, M. ; et al.
Nucl.Phys.B 52 (1973) 392-402, 1973.
Inspire Record 84261 DOI 10.17182/hepdata.50104

Measurements of the polarization parameter of the reactions π − p → π 0 n and π − p → η n at 4.90 and 7.85 GeV/ c and for a squared four-momentum transfer − t ranging from 0.1 to 2.0 (GeV/ c ) 2 have been achieved by using a butanol polarized proton target and detecting only the two γ's from the neutral meson decay. The background due to events involving bound protons has been separately measured and subtracted out. A large positive polarization has been found for the reaction π − p → π 0 n. It is consistent with other pion-nucleon scattering data connected by isospin conservation. The polarization for the reaction π − p → η n is not significantly different from zero within the large experimental errors.

2 data tables match query

No description provided.

No description provided.


Study of Hypercharge Exchange Reactions of the Type K- p --> 1- 3/2+- at 4.2-GeV/c

The Amsterdam-CERN-Nijmegen-Oxford collaboration Aguilar-Benitez, M. ; Barreiro, F. ; Hemingway, R.J. ; et al.
Nucl.Phys.B 124 (1977) 189-228, 1977.
Inspire Record 101289 DOI 10.17182/hepdata.50024

Results are presented for the quasi two-body hypercharge exchange reactions of the type using data from a high statistics bubble chamber experiment. Total and differential cross sections and the momentum transfer dependence of the meson and hyperon resonance single density matrix elements are discussed. Amplitude analyses are performed for the first two reactions. The results are compared with quark model and duality predictions and with those from other related reactions.

20 data tables match query

No description provided.

No description provided.

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Linearly polarised photon beams at ELSA and measurement of the beam asymmetry in pi^0-photoproduction off the proton

The CBELSA & TAPS collaborations Elsner, D. ; Bantes, B. ; Bartholomy, O. ; et al.
Eur.Phys.J.A 39 (2009) 373-381, 2009.
Inspire Record 799078 DOI 10.17182/hepdata.50479

At the electron accelerator ELSA a linearly polarised tagged photon beam is produced by coherent bremsstrahlung off a diamond crystal. Orientation and energy range of the linear polarisation can be deliberately chosen by accurate positioning of the crystal with a goniometer. The degree of polarisation is determined by the form of the scattered electron spectrum. Good agreement between experiment and expectations on basis of the experimental conditions is obtained. Polarisation degrees of P = 40% are typically achieved at half of the primary electron energy. The determination of P is confirmed by measuring the beam asymmetry, \Sigma, in pi^0 photoproduction and a comparison of the results to independent measurements using laser backscattering.

20 data tables match query

Beam asymmetry as a function of the PI0 centre of mass scattering angle.

Beam asymmetry as a function of the PI0 centre of mass scattering angle.

Beam asymmetry as a function of the PI0 centre of mass scattering angle.

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Neutron-proton analyzing power at 12 MeV and inconsistencies in parametrizations of nucleon-nucleon data

Braun, R.T. ; Tornow, W. ; Howell, C.R. ; et al.
Phys.Lett.B 660 (2008) 161-166, 2008.
Inspire Record 778429 DOI 10.17182/hepdata.50912

We present the most accurate and complete data set for the analyzing power Ay(theta) in neutron-proton scattering. The experimental data were corrected for the effects of multiple scattering, both in the center detector and in the neutron detectors. The final data at En = 12.0 MeV deviate considerably from the predictions of nucleon-nucleon phase-shift analyses and potential models. The impact of the new data on the value of the charged pion-nucleon coupling constant is discussed in a model study.

1 data table match query

The measured analysing power at 12 MeV. Errors contain statistics and systematics added in quadrature.


Forward Photoproduction of Neutral Pions on Polarized Protons in the Third Resonance Region

Herr, H. ; Husmann, D. ; Jansen, W. ; et al.
Nucl.Phys.B 125 (1977) 157-161, 1977.
Inspire Record 118996 DOI 10.17182/hepdata.50398

Angular distributions of the target symmetry for the reaction γ + p → π 0 + p have been measured at the Bonn 2.5 GeV Electron Synchrotron at pion c.m. angles between 13° and 63° and photon energies of 1.0 and 1.1 GeV. The π 0 mesons were detected by their two decay photons with total absorption lead-glass Čerenkov counters. Butanol was used as target material in a continuous flow 3 He cryostat operating at 0.5 K and 25 kG. The π 0 counting rate from free protons in the butanol target was derived from the measurements of the differential cross section on hydrogen. The data are compared with data of other laboratories and the results of two recent partial-wave analyses.

3 data tables match query

No description provided.

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Measurement of the transverse polarization of $\Lambda$ and $\bar{\Lambda}$ hyperons produced in proton-proton collisions at $\sqrt{s}=7$ TeV using the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Phys.Rev.D 91 (2015) 032004, 2015.
Inspire Record 1332748 DOI 10.17182/hepdata.66547

The transverse polarization of $\Lambda$ and $\bar\Lambda$ hyperons produced in proton-proton collisions at a center-of-mass energy of 7 TeV is measured. The analysis uses 760 $\mu$b$^{-1}$ of minimum bias data collected by the ATLAS detector at the LHC in the year 2010. The measured transverse polarization averaged over Feynman $x_{\rm F}$ from $5\times 10^{-5}$ to 0.01 and transverse momentum $p_{\rm T}$ from 0.8 to 15 GeV is $-0.010 \pm 0.005({\rm stat}) \pm 0.004({\rm syst})$ for $\Lambda$ and $0.002 \pm 0.006({\rm stat}) \pm 0.004({\rm syst})$ for $\bar\Lambda$. It is also measured as a function of $x_{\rm F}$ and $p_{\rm T}$, but no significant dependence on these variables is observed. Prior to this measurement, the polarization was measured at fixed-target experiments with center-of-mass energies up to about 40 GeV. The ATLAS results are compatible with the extrapolation of a fit from previous measurements to the $x_{\rm F}$ range covered by this mesurement.

5 data tables match query

Transverse polarization POL of LAMBDA and LAMBDABAR hyperons averaged over PT and XF.

Transverse polarization POL of LAMBDA and LAMBDABAR hyperons as a function of XF.

Transverse polarization POL of LAMBDA and LAMBDABAR hyperons as a function of PT.

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Scattering of π−Mesons in the Momentum Range 875-1579 MeV/c from a Polarized Proton Target

Duke, P.J. ; Jones, D.P. ; Kemp, M.A.R. ; et al.
Phys.Rev. 166 (1968) 1448-1457, 1968.
Inspire Record 1407765 DOI 10.17182/hepdata.70298

Measurements have been made of the asymmetry in the scattering of π− mesons by a polarized proton target. Scattered π mesons and recoil protons were detected in arrays of scintillation counters; data were obtained at 16 scattering angles at each of 8 beam momenta between 875 and 1578 MeV/c. Analysis of these data together with earlier differential-cross-section measurements shows that there must exist at least three resonances in this energy region: (i) mass 1920 MeV/c2, Γ=170 MeV/c2, I=32, F72; (ii) mass 1682 MeV/c2, Γ=100 MeV/c2, I=12, F52; and (iii) mass 1674 MeV/c2, Γ=100 MeV/c2, I=12, D52.

33 data tables match query

No description provided.

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Recoil proton polarization in elastic $\pi^−$ p scattering at 300 MeV and the phase shift analysis of pion-nucleon scattering

Vasilevsky, I.M. ; Vishnyakov, V.V. ; Ivanchenko, I.M. ; et al.
Phys.Lett. 23 (1966) 174-176, 1966.
Inspire Record 1408342 DOI 10.17182/hepdata.70432

The results of a measurement of recoil proton polarization for π−p → π−p at 300 MeV are given, and a phase shift analysis is made with the help of other data.

1 data table match query

No description provided.


QUADRUPOLE EFFECT IN ELASTIC PROTON SCATTERING WITH 1-GEV ENERGY ON THE NUCLEI OF THE P SHELL. (IN RUSSIAN)

Alkhazov, G.D. ; Belostotsky, S.L. ; Vorobev, A.A ; et al.
Pisma Zh.Eksp.Teor.Fiz. 29 (1979) 88-92, 1979.
Inspire Record 145178 DOI 10.17182/hepdata.70237

None

26 data tables match query

X ERROR D(THETA) = 0.2000 DEG.

X ERROR D(TARGET) = 99.60 PCT. X ERROR D(THETA) = 0.2000 DEG.

X ERROR D(THETA) = 0.2000 DEG.

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Measurement of the spin rotation parameters R and A in pi- p elastic scattering at 450-MeV and 560-MeV

Abaev, V.V. ; Bazhanov, N.A. ; Bekrenev, V.S. ; et al.
Sov.J.Nucl.Phys. 48 (1988) 852-858, 1988.
Inspire Record 457307 DOI 10.17182/hepdata.17344
3 data tables match query

No description provided.

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Tensor analyzing powers in the reactions p(d,p)d and p(d,p)p n at zero angle for incident-deuteron momenta between 3.5-GeV/c and 6.5-GeV/c.

Azhgirei, L.S. ; Chernykh, E.V. ; Ladygin, V.P. ; et al.
Phys.Atom.Nucl. 61 (1998) 432-447, 1998.
Inspire Record 474393 DOI 10.17182/hepdata.17151

None

12 data tables match query

No description provided.

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Analyzing power of collisions between polarized protons with energies in the range 0.71-GeV to 3.61-GeV and carbon nuclei

Anoshina, E.V. ; Bodyagin, V.A. ; Vardanian, I.N. ; et al.
Phys.Atom.Nucl. 60 (1997) 224-229, 1997.
Inspire Record 457394 DOI 10.17182/hepdata.17091

None

3 data tables match query

(C=EXP1) and (C=EXP2) correspond to two different method of event's registration. See text for details.

(C=EXP1) and (C=EXP2) correspond to two different method of event's registration. See text for details. Quasielastic events.

(C=EXP1) and (C=EXP2) correspond to two different method of event's registration. See text for details. Quasielastic events.


Left-right Asymmetry in Inverse $\pi^-$ Photoproduction From a Transversely Polarized Proton Target

Kim, G.J. ; Adrian, S.D. ; Arends, J. ; et al.
Phys.Rev.Lett. 56 (1986) 1779-1782, 1986.
Inspire Record 232117 DOI 10.17182/hepdata.20259

Accurate measurements of the left-right asymmetry in π−p→γn at pπ=427−625 MeV/c with a transversely polarized target are reported. Results are compared with the predictions from the Arai and Fujii single-pion photoproduction partial-wave analysis and with data on the inverse process measured with a deuterium target. The agreement is poor, casting doubt on the correctness of the value for the radiative-decay amplitude of the neutral Roper resonance now in use.

5 data tables match query

No description provided.

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Test of Charge Symmetry in Neutron - Proton Elastic Scattering at 477-{MeV}

Abegg, R. ; Bandyopadhyay, D. ; Birchall, J. ; et al.
Phys.Rev.Lett. 56 (1986) 2571, 1986.
Inspire Record 228239 DOI 10.17182/hepdata.20237

An experiment resulting in the first measurement of the isospin-mixing, charge-symmetry-violating component of the n−p interaction has been performed. The experiment determined the difference in the angles of the zero crossing of the neutron and proton analyzing powers An and Ap at 477 MeV. In terms of the laboratory scattering angle of the neutron, the measured difference is θ0n(An)−θ0n(Ap)=+0.13° ±0.06° (±0.03°), where the second error is a worst-case estimate of systematic error. The resulting difference in the analyzing powers at the zero-crossing angle is An−Ap=+0.0037 ±0.0017 (±0.0008).

1 data table match query

No description provided.


Polarization of $\Lambda^\prime$s and $\bar{\Lambda}$-primes in $P P$, $\bar{P} P$, and $K^- P$ Interactions at 176-{GeV}/c

Gourlay, S.A. ; Melanson, H.L. ; Abolins, M.A. ; et al.
Phys.Rev.Lett. 56 (1986) 2244-2247, 1986.
Inspire Record 232417 DOI 10.17182/hepdata.20240

We have measured the polarization of Λ's in inclusive pp and K−p reactions and of Λ¯'s in p¯p interactions at a beam momentum of 176 GeV/c. Data were taken in the beam-fragmentation region with hyperon transverse momenta from 0.2 to 1.5 GeV/c. The P¯ produced Λ¯'s have the same magnitude and sign of polarization as the p-produced Λ's, whereas the Λ's from K−p interactions are more highly polarized and in the opposite direction.

3 data tables match query

No description provided.

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P-d elastic cross-section and polarization at 198 mev

Adelberger, R.E. ; Brown, C.N. ;
Phys.Rev.D 5 (1972) 2139-2142, 1972.
Inspire Record 74223 DOI 10.17182/hepdata.22443

p−d elastic cross-section and polarization measurements are presented at an incident energy of 198 MeV, over the center-of-mass angular range 80° to 170°. The peak in the backward or pickup region is examined in terms of a simple nucleon-exchange parametrization.

1 data table match query

No description provided.


Polarized target asymmetry in pion proton bremsstrahlung at 298-MeV

Bosshard, A. ; Amsler, Claude ; Bistirlich, J.A. ; et al.
Phys.Rev.Lett. 64 (1990) 2619-2622, 1990.
Inspire Record 303404 DOI 10.17182/hepdata.22827

First data are presented for the polarized-target asymmetry in the reaction π+p→π+pγ at an incident pion energy of 298 MeV. The geometry was chosen to maximize the sensitivity to the radiation of the magnetic dipole moment μΔ of the Δ++(1232 MeV). A fit of the asymmetry in the cross section d5σ/dΩπ dΩγ dk as a function of the photon energy k to predictions from a recent isobar-model calculation with μΔ as the only free parameter yields μΔ=1.64(±0.19expΔ,±0.14 theor)μp. Though this value agrees with bag-model corrections to the SU(6) prediction μΔ=2μp, further clarifications on the model dependence of the result are needed, in particular since the isobar model fails to describe both the cross section and the asymmetry at the highest photon energies.

2 data tables match query

No description provided.

No description provided.


Analyzing power measurement of p p elastic scattering in the Coulomb - nuclear interference region with the 200-GeV/c polarized proton beam at Fermilab

The E581/704 collaboration Akchurin, N. ; Langland, J. ; Onel, Y. ; et al.
Phys.Rev.D 48 (1993) 3026-3036, 1993.
Inspire Record 364576 DOI 10.17182/hepdata.22670

The analyzing power AN of proton-proton elastic scattering in the Coulomb-nuclear interference region has been measured using the 200-GeV/c Fermilab polarized proton beam. A theoretically predicted interference between the hadronic non-spin-flip amplitude and the electromagnetic spin-flip amplitude is shown for the first time to be present at high energies in the region of 1.5 × 10−3 to 5.0 × 10−2 (GeV/c)2 four-momentum transfer squared, and our results are analyzed in connection with theoretical calculations. In addition, the role of possible contributions of the hadronic spin-flip amplitude is discussed.

1 data table match query

No description provided.


Measurement of the left-right asymmetry in pi- p ---> gamma n from 301-GeV/c to 625-MeV/c at backward angles

Kim, G.J. ; Engelage, J. ; Nefkens, B.M.K. ; et al.
Phys.Rev.D 43 (1991) 687-695, 1991.
Inspire Record 316108 DOI 10.17182/hepdata.22828

The left-right asymmetry of π−p→γn has been measured using a transversely polarized target at seven pion momenta from 301 to 625 MeV/c, mostly at photon angles of 90° and 110° c.m. The final-state γ and neutron were detected in coincidence. Neutrons were recorded in two arrays of plastic scintillators and the γ's in two matching sets of lead-glass counters. The results are compared with the predictions from the two most recent single-pion photoproduction partial-wave analyses. The agreement with the analysis of Arai and Fujii is poor, casting some doubt on the correctness of their values for the radiative decay amplitude of the neutral Roper resonance which are used widely. The agreement is much better with the results of the VPI analysis. Also, a comparison is made with the recoil-proton polarization data from the inverse reaction measured at 90° with a deuterium target. It reveals substantial discrepancies, indicating the shortcomings of the deuterium experiments for neutron target experiments. Our data are also compared with several bag-model calculations.

7 data tables match query

No description provided.

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Production Polarization and Magnetic Moment of $\Xi^{-+}$ Antihyperons Produced by 800-GeV/c Protons

Ho, P.M. ; Longo, M.J. ; Nguyen, A. ; et al.
Phys.Rev.Lett. 65 (1990) 1713-1716, 1990.
Inspire Record 296567 DOI 10.17182/hepdata.22752

The polarization of Ξ¯ + hyperons produced by 800-GeV/c protons in the inclusive reaction p+Be→Ξ¯ ++X has been measured. The average polarization of the Ξ¯ +, at a mean xF=0.39 and pt=0.76 GeV/c, is -0.097±0.012±0.009. The magnetic moment of the Ξ¯ + is 0.657±0.028±0.020 nuclear magneton.

3 data tables match query

No description provided.

No description provided.

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Test of spin dependence in charm-quark fragmentation to D*.

The TPC/Two-Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Avery, R.E. ; et al.
Phys.Rev.D 43 (1991) 29-33, 1991.
Inspire Record 316132 DOI 10.17182/hepdata.22830

We have measured the polarization of D*, the energy dependence of the polarization, and the spin-density matrix of D* in e+e− annihilation at a center-of-mass energy of 29 GeV using the Time Projection Chamber detector at the SLAC storage ring PEP. In 147 pb−1 of data we see no strong evidence for polarization, alignment, or final-state interactions in this fragmentation process.

2 data tables match query

Polarization is the factor alpha(z) in the expression d width (D*-->D pi)/domega = C(1+alpha(z)cos(theta)**2).

Spin density matrices for D* --> D0 pi+.


Pi+ photoproduction from hydrogen with polarized photons

Bar-Yam, Z. ; De Pagter, J. ; Dowd, J. ; et al.
Phys.Rev.Lett. 25 (1970) 1053-1056, 1970.
Inspire Record 62861 DOI 10.17182/hepdata.21600

The reaction γ⊥,∥p→π+n has been studied with linearly polarized photons of energy 3.0 GeV at −t values between 0.15 and 1.2 (GeVc)2. The asymmetry A+=(dσ⊥−dσ∥)(dσ⊥+dσ∥) is found to be positive throughout this four-momentum-transfer range, implying the dominance of natural parity exchange in the t channel. Comparison of dσ⊥(γ⊥p→π+n) and dσ⊥p→π−p) from a previous experiment indicates strong interference between the isoscalar and isovector photon amplitudes for photons polarized perpendicular to the production plane.

3 data tables match query

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RECOIL PROTON POLARIZATION IN ETA PHOTOPRODUCTION

Heusch, C.A. ; Prescott, C.Y. ; Rochester, L.S. ; et al.
Phys.Rev.Lett. 25 (1970) 1381, 1970.
Inspire Record 61494 DOI 10.17182/hepdata.21581

We measured the polarization of the recoil proton in the process γp→pη0, at 90° in the center-of-mass system, at incoming photon energies from 0.8 to 1.1 GeV. Detection of all three particles in the final state pγγ permitted observation of this process with little background. Subsequent rescattering off carbon nuclei yielded sizable polarization values for the protons, indicating considerable S−P—wave interference in the production process.

1 data table match query

No description provided.


Measurement of Polarization in $\pi^- p \to \pi^0n$ and $\pi^-p \to \eta n$

Drobnis, D.D. ; Lales, J. ; Lamb, R.C. ; et al.
Phys.Rev.Lett. 20 (1968) 274-278, 1968.
Inspire Record 942917 DOI 10.17182/hepdata.21731

None

6 data tables match query

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Polarization of Recoil Protons from the Photoproduction of pi0 Mesons from Hydrogen

Stein, P.C. ;
Phys.Rev.Lett. 2 (1959) 473-475, 1959.
Inspire Record 944911 DOI 10.17182/hepdata.21754

None

1 data table match query

No description provided.


Production of single negative pions from deuterium with polarized photons

Bar-Yam, Z. ; De Pagter, J. ; Dowd, J. ; et al.
Phys.Rev.Lett. 24 (1970) 1078-1081, 1970.
Inspire Record 62952 DOI 10.17182/hepdata.21628

The asymmetry A=(dσ⊥−dσ∥)(dσ⊥+dσ∥) of the differential cross section for the reaction γd→π−pp has been studied with linearly polarized photons of 3.0 GeV at squared four-momentum-transfers between 0.15 and 2.0 (GeV/c)2. The asymmetry was found to be positive at −t values below 0.3 (GeV/c)2, dipping to negative values between 0.4 and 0.6 (GeV/c)2, and then rising again to positive values above 0.7 (GeV/c)2.

1 data table match query

Axis error includes +- 11/11 contribution.


Polarization in pp Elastic Scattering at Large Momentum Transfers

Booth, N.E. ; Conforto, G. ; Esterling, R.J. ; et al.
Phys.Rev.Lett. 21 (1968) 651-652, 1968.
Inspire Record 944913 DOI 10.17182/hepdata.21669

Measurements of the polarization in pp elastic scattering have been made at 5.15 GeV/c over the range −t=0.2 to 1.8 (GeV/c)2. The data are compared with a Regge-pole model, and with the diffraction model of Durand and Lipes in which the absorptive part of the pp interaction is derived from the electromagnetic form factor of the proton. The latter model reproduces the t dependence of the experimental data in a qualitative way.

1 data table match query

RECOIL PROTON POLARIZATION IN pi0 PHOTOPRODUCTION

Bloom, Elliott D. ; Heusch, C.A. ; Prescott, C.Y. ; et al.
Phys.Rev.Lett. 19 (1967) 671, 1967.
Inspire Record 51327 DOI 10.17182/hepdata.21757

None

1 data table match query

No description provided.


Measurement of the Recoil Proton Polarization in Elastic $\pi^-p$ Scattering at $T_\pi=410$ and 492 MeV

Bareyre, P. ; Bricman, C. ; Longo, M.J. ; et al.
Phys.Rev.Lett. 14 (1965) 878-880, 1965.
Inspire Record 945162 DOI 10.17182/hepdata.21824

None

2 data tables match query

No description provided.

No description provided.


Pi+- p elastic scattering and pi+ p ---> k+ sigma+ at 5.0 gev/c near -t=3.0(gev/c)-squared

Akerlof, C.W. ; Caldwell, P.K. ; Kalbaci, P. ; et al.
Phys.Rev.Lett. 27 (1971) 219-222, 1971.
Inspire Record 68949 DOI 10.17182/hepdata.21476

We have measured the reactions π±p→π±p and π+p→K+Σ+ at 5.0 GeV/c in the region 2.2<−t<3.5 (GeV/c)2. We find the minimum cross section of the dip at −t=2.8 (GeV/c)2 in π+p elastic scattering to be 0.16 ± 0.05 μb/GeV2. The π−p differential cross section exhibits similar structure, while the π+p→K+Σ+ channel shows a steady decline in cross section as |t| increases. The polarization of the Σ+ remains large and positive to at least −t=2.8 (GeV/c)2.

4 data tables match query

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Polarization of Lambda Hyperons from Photoproduction in Hydrogen

Thom, H. ; Gabathuler, E. ; Jones, D. ; et al.
Phys.Rev.Lett. 11 (1963) 433-435, 1963.
Inspire Record 48006 DOI 10.17182/hepdata.21857

None

1 data table match query

No description provided.


Measurement of the Recoil Proton Polarization in Elastic pi+p Scattering at Tpi=410and492 MeV

Bareyre, P. ; Bricman, C. ; Longo, M.J. ; et al.
Phys.Rev.Lett. 14 (1965) 198-201, 1965.
Inspire Record 944925 DOI 10.17182/hepdata.21847

None

2 data tables match query

No description provided.

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Pi+- and pi0 production by polarized photons in the resonance region

Alspector, J. ; Fox, D. ; Luckey, David ; et al.
Phys.Rev.Lett. 28 (1972) 1403-1406, 1972.
Inspire Record 75484 DOI 10.17182/hepdata.21872

We have measured the cross sections at 90° c.m. for π± and π0 photoproduction with polarized photons. The photon energies ranged from 0.8 to 2.2 GeV. We compare the resonant "bumps" in the cross section with theoretical models. The measured asymmetry agrees with a quark-model calculation though the predicted cross sections are low.

5 data tables match query

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Large angle elastic proton proton polarization at 5.15 gev/c

Abshire, G.W. ; Ankenbrandt, C.M. ; Crittenden, R.R. ; et al.
Phys.Rev.D 9 (1974) 555-559, 1974.
Inspire Record 93113 DOI 10.17182/hepdata.21953

We present herein the initial results of a large-angle elastic p−p polarization experiment which is now in progress at the Argonne ZGS (Zero-Gradient Synchrotron) accelerator. Data for the incident proton momentum of 5.15 GeVc are presented for 30∘≲θc.m.≲90∘. These results, which extend to t≈−4.0(GeVc)2, represent the first high-statistics p−p polarization measurements for |t| values greater than ∼2.5 (GeVc)2. We observe a minimum in the polarization near t=−0.8(GeVc)2, a smooth increase in the polarization until a maximum is attained near t=−1.8(GeVc)2, and then a monotonic decline in the polarization until the value of zero is reached at θc.m.=90∘. The data are analyzed in terms of an optical model.

1 data table match query

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Polarization measurements in medium-energy elastic scattering and high-energy models

Andersson, S. ; Daum, C. ; Erne, F.C. ; et al.
Conf.Proc.C 690905 (1969) 21-49, 1969.
Inspire Record 1091653 DOI 10.17182/hepdata.21876

None

2 data tables match query

'2'. 'N1'. '3'.


Negative-pion photoproduction from neutrons by linearly polarized photons in the first resonance region

Kondo, K. ; Miyachi, T. ; Ukai, K. ; et al.
Phys.Rev.D 9 (1974) 529-533, 1974.
Inspire Record 93115 DOI 10.17182/hepdata.21954

The angular dependence of the asymmetry for negative-pion photoproduction on neutrons by linearly polarized photons has been measured for photon energies 260, 300, 350, 400, 450, and 500 MeV at center-of-mass angles 60°, 75°, 90°, 150°, and 120°. The results are compared with theoretical models of low-energy single-pion photoproduction. The observed asymmetry below 400 MeV shows good agreement with predictions of dispersion-theoretical models by Berends, Donnachie, and Weaver and by Schwela. The asymmetry values in the 400-500 MeV energy region suggest that smaller M1− amplitude is more favorable.

6 data tables match query

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Measurements of the polarization in proton proton elastic scattering from 2.50 to 5.15 gev/c

Parry, J.H. ; Booth, N.E. ; Conforto, G. ; et al.
Phys.Rev.D 8 (1973) 45-63, 1973.
Inspire Record 81983 DOI 10.17182/hepdata.22058

In an experiment at the Argonne Zero-Gradient Synchrotron we have measured values of the polarization parameter P(t) in the elastic scattering of negative pions, positive pions, positive kaons, and protons on protons at several incident laboratory momenta from 2.50 to 5.15 GeVc, and for values of the momentum transfer variable −t from 0.2 to 2.0 (GeVc)2. The final results from p−p elastic scattering presented here extend our knowledge of the polarization to much larger values of −t than the results of previous measurements. Outstanding features revealed by these polarization data include (1) the development of a dip at about −t=0.7 (GeVc)2, with (2) a substantial secondary peak at larger values of −t and (3) the gradual diminution of the maximum polarization with increasing energy. It is possible to fit the t dependence of the experimental results with a simple model. The energy dependence of the polarized cross sections is also discussed.

7 data tables match query

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Measurement of the polarization parameter in k+ p elastic scattering

Barnett, B.A. ; Laasanen, A.T. ; Koehler, P.F.M. ; et al.
Phys.Rev.D 8 (1973) 2751-2764, 1973.
Inspire Record 93326 DOI 10.17182/hepdata.22081

Full angular distributions of the polarization parameter in elastic K+p scattering at 1.37, 1.45, 1.60, 1.71, 1.80, 1.89, 2.11, and 2.31 GeV/c are presented. These data were obtained in an experiment at the Zero Gradient Synchrotron using a polarized proton target with arrays of scintillation and Čerenkov counters to detect the scattered particles.

8 data tables match query

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Measurement of analyzing powers of pi + and pi - produced on a hydrogen and a carbon target with a 22-GeV/c incident polarized proton beam

Allgower, C.E. ; Krueger, K.W. ; Kasprzyk, T.E. ; et al.
Phys.Rev.D 65 (2002) 092008, 2002.
Inspire Record 587580 DOI 10.17182/hepdata.22221

The analyzing powers of π+ and π− were measured using an incident 22−GeV/c transversely polarized proton beam at the Brookhaven Alternating Gradient Synchrotron. A magnetic spectrometer measured π± inclusive asymmetries on a hydrogen and a carbon target. An elastic polarimeter with a CH2 target measured pp elastic-scattering asymmetries to determine the beam polarization using published data for the pp elastic analyzing power. Using the beam polarization determined from the elastic polarimeter and asymmetries from the inclusive spectrometer, analyzing powers AN for π± were determined in the xF and pT ranges (0.45–0.8) and (0.3–1.2 GeV/c), respectively. The analyzing power results are similar in both sign and character to other measurements at 200 and 11.7 GeV/c, confirming the expectation that high-energy pion inclusive analyzing powers remain large and relatively energy independent. This suggests that pion inclusive polarimetry may be a suitable method for measuring future beam polarizations at BNL RHIC or DESY HERA. Analyzing powers of π+ and π− produced on hydrogen and carbon targets are the same. Various models to explain inclusive analyzing powers are also discussed.

7 data tables match query

Analyzing power measurements for PI+ and PI- production on the carbon target at incident momentum 21.6 GeV. See text of article for definitions of method 'A' and 'B'.

Analyzing power measurements for inclusive PI- production from the hydrogen target.

Analyzing power measurements for inclusive PI+ production from the hydrogen target.

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Sigma+ polarization in pi+ n ---> k0 sigma+ from 1.1 to 2.4 gev/c

Davies, D.W. ; Abolins, M.A. ; Dahl, O.I. ; et al.
Phys.Rev.D 7 (1973) 3546-3548, 1973.
Inspire Record 82052 DOI 10.17182/hepdata.22133

We observe an energy-dependent polarization of the Σ+ produced in the reaction π+n→K0Σ+ at incident beam momenta between 1.1 and 2.4 GeV/c. These data form a significant source of information on the Σ− polarization in the charge-symmetric reaction π−p→K+Σ−.

2 data tables match query

INTEGRATED OVER ALL PRODUCTION ANGLES.

No description provided.