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The Spin-dependent Structure Function of the Proton g_1^p and a Test of the Bjorken Sum Rule

The COMPASS collaboration Alekseev, M.G. ; Alexakhin, V.Yu. ; Alexandrov, Yu. ; et al.
Phys.Lett. B690 (2010) 466-472, 2010.
Inspire Record 843494 DOI 10.17182/hepdata.61588
2 data tables

Values of A1P and G1P as a function of X with corresponding average values of Q**2.

Values of $g_1^p$ for the 2007 COMPASS proton data at 160 GeV in ($x$, $Q^2$) bins.


Final COMPASS results on the deuteron spin-dependent structure function $g_1^{\rm d}$ and the Bjorken sum rule

The COMPASS collaboration Adolph, C. ; Aghasyan, M. ; Akhunzyanov, R. ; et al.
Phys.Lett. B769 (2017) 34-41, 2017.
Inspire Record 1501480 DOI 10.17182/hepdata.78374

Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a 6 LiD target. The data were taken at 160 GeV beam energy and the results are shown for the kinematic range 1(GeV/c)2<Q2<100(GeV/c)2 in photon virtuality, 0.004<x<0.7 in the Bjorken scaling variable and W>4GeV/c2 in the mass of the hadronic final state. The deuteron double-spin asymmetry A1d and the deuteron longitudinal-spin structure function g1d are presented in bins of x and Q2 . Towards lowest accessible values of x , g1d decreases and becomes consistent with zero within uncertainties. The presented final g1d values together with the recently published final g1p values of COMPASS are used to again evaluate the Bjorken sum rule and perform the QCD fit to the g1 world data at next-to-leading order of the strong coupling constant. In both cases, changes in central values of the resulting numbers are well within statistical uncertainties. The flavour-singlet axial charge a0 , which is identified in the MS‾ renormalisation scheme with the total contribution of quark helicities to the nucleon spin, is extracted at next-to-leading order accuracy from only the COMPASS deuteron data: a0(Q2=3(GeV/c)2)=0.32±0.02stat±0.04syst±0.05evol . Together with the recent results on the proton spin structure function g1p , the results on g1d constitute the COMPASS legacy on the measurements of g1 through inclusive spin-dependent deep inelastic scattering.

6 data tables

Values of $A_1^d$ and $g_1^d$ for the COMPASS deuteron data at 160 GeV in $x$ bins averaged over $Q^2$.

Values of $A_1^d$ and $g_1^d$ for the COMPASS deuteron data at 160 GeV in (x, $Q^2$) bins.

Values of $g_1^{NS}$ for the COMPASS data in $x$ bins averaged over $Q^2$.

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The spin structure function $g_1^{\rm p}$ of the proton and a test of the Bjorken sum rule

The COMPASS collaboration Adolph, C. ; Akhunzyanov, R. ; Alexeev, M.G. ; et al.
Phys.Lett. B753 (2016) 18-28, 2016.
Inspire Record 1357198 DOI 10.17182/hepdata.72819

New results for the double spin asymmetry A1p and the proton longitudinal spin structure function g1p are presented. They were obtained by the COMPASS Collaboration using polarised 200 GeV muons scattered off a longitudinally polarised NH 3 target. The data were collected in 2011 and complement those recorded in 2007 at 160 GeV, in particular at lower values of x . They improve the statistical precision of g1p(x) by about a factor of two in the region x≲0.02 . A next-to-leading order QCD fit to the g1 world data is performed. It leads to a new determination of the quark spin contribution to the nucleon spin, ΔΣ, ranging from 0.26 to 0.36, and to a re-evaluation of the first moment of g1p . The uncertainty of ΔΣ is mostly due to the large uncertainty in the present determinations of the gluon helicity distribution. A new evaluation of the Bjorken sum rule based on the COMPASS results for the non-singlet structure function g1NS(x,Q2) yields as ratio of the axial and vector coupling constants |gA/gV|=1.22±0.05 (stat.)±0.10 (syst.) , which validates the sum rule to an accuracy of about 9%.

3 data tables

Values of $A_1^{\rm p}$ and $g_1^{\rm p}$ for the 2011 COMPASS data at 200 GeV in ($x$, $Q^2$) bins.

Values of $A_1^{\rm p}$ and $g_1^{\rm p}$ for the 2011 COMPASS data at 200 GeV in $x$ bins averaged over $Q^2$.

Values of $A_1^{\rm p}$ for the 2007 COMPASS data at 160 GeV in ($x$, $Q^2$) bins.


A Reevaluation of the Gottfried sum

The New Muon collaboration Arneodo, M. ; Arvidson, A. ; Badelek, B. ; et al.
Phys.Rev. D50 (1994) R1-R3, 1994.
Inspire Record 358419 DOI 10.17182/hepdata.71293
4 data tables

Errors of F2(D) are the estimated total uncertainties and those on the ratio and difference are statistical only.

Values of the Gottfried Sum Rule integral (GS) defined as the integral between X(C=MIN) and X = 0.8 of (F2(P)-F2(N))DX/X.

No description provided.

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Spin asymmetries A(1) and structure functions g1 of the proton and the deuteron from polarized high-energy muon scattering

The Spin Muon collaboration Adeva, B. ; Akdogan, T. ; Arik, E. ; et al.
Phys.Rev. D58 (1998) 112001, 1998.
Inspire Record 471981 DOI 10.17182/hepdata.49492
12 data tables

The virtual photon proton asymmetries.

The virtual photon deuteron asymmetries.

The virtual photon proton asymmetries in smaller X and Q**2 bins. bins. Errors are statistical only.

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A Next-to-leading order QCD analysis of the spin structure function g(1)

The Spin Muon collaboration Adeva, B. ; Akdogan, T. ; Arik, E. ; et al.
Phys.Rev. D58 (1998) 112002, 1998.
Inspire Record 471982 DOI 10.17182/hepdata.49415
7 data tables

The second systematic (DSYS) error is due to QCD evolution.

First moments of the fitted function G1 evaluated on unmeasured X regions. Total uncertainties due to experimental systematics and theoretical sourc es in the QCD evolution.

First moment of fitted G1 evaluated on the whole X region.

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The Spin dependent structure function g(1) (x) of the proton from polarized deep inelastic muon scattering

The Spin Muon (SMC) collaboration Adeva, B. ; Arik, E. ; Arvidson, A. ; et al.
Phys.Lett. B412 (1997) 414-424, 1997.
Inspire Record 448371 DOI 10.17182/hepdata.47369
4 data tables

The virtual photon proton asymmetries. Only statistical errors are given.

The virtual photon proton asymmetries A1 and the spin dependent structure function G1.

The spindependent tructure function G1 evolved to Q2 = 10 GEV**2.. The second DSYS for this indicates the uncertainty in the QCD evolution.

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The Spin dependent structure function g1(x) of the deuteron from polarized deep inelastic muon scattering

The Spin Muon (SMC) collaboration Adams, D. ; Adeva, B. ; Akdogan, T. ; et al.
Phys.Lett. B396 (1997) 338-348, 1997.
Inspire Record 440053 DOI 10.17182/hepdata.47513
6 data tables

Measurements of the transverse virtual photon asymmetry A2. Statistical errors only.

The virtual-photon deuteron cross section asymmetry A1 from the combined SMC data. Statistical errors only.

The spin dependent structure function G1(D).

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Spin structure of the proton from polarized inclusive deep inelastic muon - proton scattering

The Spin Muon (SMC) collaboration Adams, D. ; Adeva, B. ; Arik, E. ; et al.
Phys.Rev. D56 (1997) 5330-5358, 1997.
Inspire Record 440355 DOI 10.17182/hepdata.47485

We have measured the spin-dependent structure function $g_1~p$ in inclusive deep-inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003 < x < 0.7$ and $1 GeV~2 < Q~2 < 60 GeV~2$. A next-to-leading order QCD analysis is used to evolve the measured $g_1~p(x,Q~2)$ to a fixed $Q~2_0$. The first moment of $g_1~p$ at $Q~2_0 = 10 GeV~2$ is $\Gamma~p = 0.136\pm 0.013(stat.) \pm 0.009(syst.)\pm 0.005(evol.)$. This result is below the prediction of the Ellis-Jaffe sum rule by more than two standard deviations. The singlet axial charge $a_0$ is found to be $0.28 \pm 0.16$. In the Adler-Bardeen factorization scheme, $\Delta g \simeq 2$ is required to bring $\Delta \Sigma$ in agreement with the Quark-Parton Model. A combined analysis of all available proton and deuteron data confirms the Bjorken sum rule.

11 data tables

Data for Q**2 > 1 GeV**2.

Data for Q**2 > 0.2 GeV**2.

Statistical errors only.

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Accurate measurement of F2(d) / F2(p) and R**d - R**p

The New Muon collaboration Arneodo, M. ; Arvidson, A. ; Badelek, B. ; et al.
Nucl.Phys. B487 (1997) 3-26, 1997.
Inspire Record 426595 DOI 10.17182/hepdata.32750
23 data tables

No description provided.

No description provided.

No description provided.

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Measurement of the proton and the deuteron structure functions, F2(p) and F2(d)

The New Muon collaboration Arneodo, M. ; Arvidson, A. ; Badelek, B. ; et al.
Phys.Lett. B364 (1995) 107-115, 1995.
Inspire Record 400018 DOI 10.17182/hepdata.48061

The proton and deuteron structure functions F2p and F2d were measured in the kinematic range 0.006<x<0.6 and 0.5<Q~2<75 GeV~2, by inclusive deep inelastic muon scattering at 90, 120, 200 and 280 GeV. The measurements are in good agreement with earlier high precision results. The present and earlier results together have been parametrised to give descriptions of the proton and deuteron structure functions F2 and their uncertainties over the range 0.006<x<0.9.

30 data tables

No description provided.

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Proton and deuteron structure functions in muon scattering at 470-GeV

The E665 collaboration Adams, M.R. ; Aid, S. ; Anthony, P.L. ; et al.
Phys.Rev. D54 (1996) 3006-3056, 1996.
Inspire Record 416076 DOI 10.17182/hepdata.42347
34 data tables

No description provided.

No description provided.

No description provided.

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Results from SMC on the spin dependent structure function g1(p) of the proton

The Spin Muon collaboration Witzmann, A. ;
Nucl.Phys. A577 (1994) 319C-324C, 1994.
Inspire Record 386220 DOI 10.17182/hepdata.36521
1 data table

First moment of the spin-dependent structure function G1.


The Present status of the nucleon spin structure functions

The Spin Muon collaboration Horikawa, N. ;
Nucl.Phys. A577 (1994) 313C-318C, 1994.
Inspire Record 386219 DOI 10.17182/hepdata.36532
1 data table

First moment of the spin-dependent structure function G1.


Extraction of the ratio $F2_n / F2_p$ from muon - deuteron and muon - proton scattering at small $x$ and Q**2

The E665 collaboration Adams, M.R. ; Aid, S. ; Anthony, P.L. ; et al.
Phys.Rev.Lett. 75 (1995) 1466-1470, 1995.
Inspire Record 393866 DOI 10.17182/hepdata.42379
2 data tables

F2(N) / F2(P) = 2F2(DEUT)/F2(P) - 1.

F2(N) / F2(P) = 2F2(DEUT)/F2(P) - 1. The systematic uncertainty in the Q**2 dependece is negligible as compared to the statistical uncertainty.


Spin asymmetry in muon - proton deep inelastic scattering on a transversely polarized target

The Spin Muon (SMC) collaboration Adams, D. ; Adeva, B. ; Arik, E. ; et al.
Phys.Lett. B336 (1994) 125-130, 1994.
Inspire Record 375478 DOI 10.17182/hepdata.48344

We measured the spin asymmetry in the scattering of 100 GeV longitudinally-polarized muons on transversely polarized protons. The asymmetry was found to be compatible with zero in the kinematic range $0.006<x<0.6$, $1<Q~2<30\,\mbox{GeV}~2$. {}From this result we derive the upper limits for the virtual photon--proton asymmetry $A_2$, and for the spin structure function $g_2$. For $x<0.15$, $A_2$ is significantly smaller than its positivity limit $\sqrt{R}$.

2 data tables

No description provided.

Nucleon spin structure function g2.


Measurement of the spin dependent structure function $g_1(x)$ of the proton

The Spin Muon (SMC) collaboration Adams, D. ; Adeva, B. ; Arik, E. ; et al.
Phys.Lett. B329 (1994) 399-406, 1994.
Inspire Record 373036 DOI 10.17182/hepdata.48171

: We have measured the spin-dependent structure function $g_1~p$ of the proton in deep inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003<x<0.7$ and $1\,\mbox{GeV}~2<Q~2<60\,\mbox{GeV}~2$. Its first moment, $\int_0~1 g_1~p(x) dx $, is found to be $0.136 \pm 0.011\,(\mbox{stat.})\pm 0.011\,(\mbox{syst.})$ at $Q~2=10\,\mbox{GeV}~2$. This value is smaller than the prediction of the Ellis--Jaffe sum rule by two standard deviations, and is consistent with previous measurements. A combined analysis of all available proton, deuteron and neutron data confirms the Bjorken sum rule to within $10\%$ of the theoretical value.

3 data tables

Results on the virtual photon proton asymmetry.

Results on the spin structure function of the proton.

Data for g1 at fixed Q**2 = 10 GeV (assuming no Q**2 dependence of A1).


Measurement of the ratio $\sigma_n / \sigma_p$ in inelastic muon - nucleon scattering at very low $x$ and $Q^2$

The E665 collaboration Adams, M.R. ; Aid, S. ; Anthony, P.L. ; et al.
Phys.Lett. B309 (1993) 477-482, 1993.
Inspire Record 354238 DOI 10.17182/hepdata.28907
2 data tables

No description provided.

No description provided.


Measurements of R(d) - R(p) and R(Ca) - R(C) in deep inelastic muon scattering

The New Muon collaboration Amaudruz, P. ; Arneodo, M. ; Arvidson, A. ; et al.
Phys.Lett. B294 (1992) 120-126, 1992.
Inspire Record 340582 DOI 10.17182/hepdata.29038
4 data tables

No description provided.

Average overall x values.

No description provided.

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A QCD analysis of the proton structure function F2 (x,Q**3)

Bazizi, K. ; Wimpenny, S.J. ;
Conference Paper, 1991.
Inspire Record 317334 DOI 10.17182/hepdata.50358
59 data tables

No description provided.

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The ratio F2(n) / F2(p) in deep inelastic muon scattering

The New Muon collaboration Amaudruz, P. ; Arneodo, M. ; Arvidson, A. ; et al.
Nucl.Phys. B371 (1992) 3-31, 1992.
Inspire Record 321412 DOI 10.17182/hepdata.32955
16 data tables

No description provided.

No description provided.

Merged 90 and 280 GeV data.

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The Gottfried sum from the ratio F2(n) / F2(p)

The New Muon collaboration Amaudruz, P. ; Arneodo, M. ; Arvidson, A. ; et al.
Phys.Rev.Lett. 66 (1991) 2712-2715, 1991.
Inspire Record 313931 DOI 10.17182/hepdata.19908
1 data table

No description provided.


Measurement of the neutron and the proton F2 structure function ratio

The New Muon (NMC) collaboration Allasia, D. ; Amaudruz, P. ; Arneodo, M. ; et al.
Phys.Lett. B249 (1990) 366-372, 1990.
Inspire Record 298077 DOI 10.17182/hepdata.29644
1 data table

No description provided.


A Comparison of the Structure Functions F2 of the Proton and the Neutron From Deep Inelastic Muon Scattering at High $Q^2$

The BCDMS collaboration Benvenuti, A.C. ; Bollini, D. ; Bruni, G. ; et al.
Phys.Lett. B237 (1990) 599-604, 1990.
Inspire Record 285519 DOI 10.17182/hepdata.29734
2 data tables

No description provided.

No description provided.


An Investigation of the Spin Structure of the Proton in Deep Inelastic Scattering of Polarized Muons on Polarized Protons

The European Muon collaboration Ashman, J. ; Badelek, B. ; Baum, Guenter ; et al.
Nucl.Phys. B328 (1989) 1, 1989.
Inspire Record 280143 DOI 10.17182/hepdata.49587
7 data tables

THE MEAN Q**2 FOR EACH OF THE 10 VALUES OF X BELOW ARE 3.5,4.5,6.0, 8.010.3,12.9,15.2,18.0,22.5,29.5.

No description provided.

No description provided.

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