Date

Indications of Conical Emission of Charged Hadrons at RHIC

The STAR collaboration Abelev, B.I. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.Lett. 102 (2009) 052302, 2009.
Inspire Record 785050 DOI 10.17182/hepdata.102085

Three-particle azimuthal correlation measurements with a high transverse momentum trigger particle are reported for pp, d+Au, and Au+Au collisions at 200 GeV by the STAR experiment. The acoplanarities in pp and d+Au indicate initial state kT broadening. Larger acoplanarity is observed in Au+Au collisions. The central Au+Au data show an additional effect signaling conical emission of correlated charged hadrons.

14 data tables

FIG. 1: (a) Raw two-particle correlation signal $Y_2$ (red), background $aB_{inc}F_2$ (solid histogram), and background systematic uncertainty from a (dashed histograms). (b) Background-subtracted two-particle correlation $\hat{Y}_2$ (red), and systematic uncertainties due to a (dashed histograms) and flow (blue histograms). (c) Raw three-particle correlation $Y_3$. (d) $ba^2Y_{inc}^2$ . (e) Sum of trig-corr-bkgd and trigger flow. Data are from 12% central Au+Au collisions. Statistical errors in (a,b) are smaller than the point size. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.

FIG. 1: (a) Raw two-particle correlation signal $Y_2$ (red), background $aB_{inc}F_2$ (solid histogram), and background systematic uncertainty from a (dashed histograms). (b) Background-subtracted two-particle correlation $\hat{Y}_2$ (red), and systematic uncertainties due to a (dashed histograms) and flow (blue histograms). (c) Raw three-particle correlation $Y_3$. (d) $ba^2Y_{inc}^2$ . (e) Sum of trig-corr-bkgd and trigger flow. Data are from 12% central Au+Au collisions. Statistical errors in (a,b) are smaller than the point size. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.

FIG. 1: (a) Raw two-particle correlation signal $Y_2$ (red), background $aB_{inc}F_2$ (solid histogram), and background systematic uncertainty from a (dashed histograms). (b) Background-subtracted two-particle correlation $\hat{Y}_2$ (red), and systematic uncertainties due to a (dashed histograms) and flow (blue histograms). (c) Raw three-particle correlation $Y_3$. (d) $ba^2Y_{inc}^2$ . (e) Sum of trig-corr-bkgd and trigger flow. Data are from 12% central Au+Au collisions. Statistical errors in (a,b) are smaller than the point size.

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Measurement of the shape of the boson transverse momentum distribution in p anti-p ---> Z / gamma* ---> e+ e- + X events produced at s**(1/2) = 1.96-TeV

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.Lett. 100 (2008) 102002, 2008.
Inspire Record 769689 DOI 10.17182/hepdata.50920

We present a measurement of the shape of the Z/gamma* boson transverse momentum (qT) distribution in ppbar -> Z/gamma* -> ee+X events at a center-of-mass energy of 1.96 TeV using 0.98 fb-1 of data collected with the D0 detector at the Fermilab Tevatron collider. The data are found to be consistent with the resummation prediction at low qT, but above the perturbative QCD calculation in the region of qT>30 GeV/c. Using events with qT<30 GeV/c, we extract the value of g2, one of the non-perturbative parameters for the resummation calculation. Data at large boson rapidity y are compared with the prediction of resummation and with alternative models that employ a resummed form factor with modifications in the small Bjorken x region of the proton wave function.

3 data tables

Normalized differential transverse momentum spectrum for Z0/GAMMA* events.

Correlation matrix for all rapidity Z bosons for the 12 bins used for PT < 30.

Normalized differential transverse momentum spectrum for Z0/GAMMA* events for the absolute rapidity region > 2 and PT < 30 GeV.


Precise determination of the spin structure function g(1) of the proton, deuteron and neutron.

The HERMES collaboration Airapetian, A. ; Akopov, N. ; Akopov, Z. ; et al.
Phys.Rev.D 75 (2007) 012007, 2007.
Inspire Record 726689 DOI 10.17182/hepdata.11211

Precise measurements of the spin structure functions of the proton $g_1^p(x,Q^2)$ and deuteron $g_1^d(x,Q^2)$ are presented over the kinematic range $0.0041 \leq x \leq 0.9$ and $0.18 $ GeV$^2$ $\leq Q^2 \leq 20$ GeV$^2$. The data were collected at the HERMES experiment at DESY, in deep-inelastic scattering of 27.6 GeV longitudinally polarized positrons off longitudinally polarized hydrogen and deuterium gas targets internal to the HERA storage ring. The neutron spin structure function $g_1^n$ is extracted by combining proton and deuteron data. The integrals of $g_1^{p,d}$ at $Q^2=5$ GeV$^2$ are evaluated over the measured $x$ range. Neglecting any possible contribution to the $g_1^d$ integral from the region $x \leq 0.021$, a value of $0.330 \pm 0.011\mathrm{(theo.)}\pm0.025\mathrm{(exp.)}\pm 0.028$(evol.) is obtained for the flavor-singlet axial charge $a_0$ in a leading-twist NNLO analysis.

23 data tables

Integrals of G1 for P, DEUT and N targets.. The second DSYS systematic error is due to the uncertainty in the parameterizations (R, F2, A2, Azz, omegaD).. The third DSYS systematic error is due to the uncertainty in evolving to a common Q**2.

Integrals of G1 for the Non-Singlet contributions.. The second DSYS systematic error is due to the uncertainty in the parameterizations (R, F2, A2, Azz, omegaD).. The third DSYS systematic error is due to the uncertainty in evolving to a common Q**2. Axis error includes +- 5.2/5.2 contribution.

Integrals of G1 over different X ranges for P target at various Q*2 values. The second DSYS systematic error is due to the uncertainty in the parameterizations (R, F2, A2, Azz, omegaD).. The third DSYS systematic error is due to the uncertainty in evolving to a common Q**2. Axis error includes +- 5.2/5.2 contribution.

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Determination of $\alpha^- s$ From Energy-energy Correlations in $e^+ e^-$ Annihilation at 29-{GeV}

Wood, D.R. ; Petersen, A. ; Abrams, G.S. ; et al.
Phys.Rev.D 37 (1988) 3091, 1988.
Inspire Record 250899 DOI 10.17182/hepdata.23323

We have studied the energy-energy correlation in e+e− annihilation into hadrons at √s =29 GeV using the Mark II detector at the SLAC storage ring PEP. We find to O(αs2) that αs=0.158±0.003±0.008 if hadronization is described by string fragmentation. Independent fragmentation schemes give αs=0.10–0.14, and give poor agreement with the data. A leading-log shower fragmentation model is found to describe the data well.

6 data tables

Correlation data from the original PEP-5 detector.

Correlation Asymmetry data from the original PEP-5 detector.

Correlation data from the upgraded detector.

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STUDY OF BARYON CORRELATIONS IN e+ e- ANNIHILATION AT 29-GeV

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Avery, R.E. ; et al.
Phys.Rev.Lett. 57 (1986) 3140, 1986.
Inspire Record 236028 DOI 10.17182/hepdata.20193

We report measurements of two-particle correlations in rapidity space between a p¯ or Λ¯ and an additional p, p¯, Λ, or Λ¯. We find evidence for local conservation of baryon number, and for the first time observe a pronounced anticorrelation between baryons with the same value of baryon number. Such an anticorrelation is expected in fragmentation models where the rapidity order of particles closely reflects their ‘‘color order,’’ as is the case, for example, in recent versions of the Lund string model.

1 data table

No description provided.


OBSERVATION OF STRANGENESS CORRELATIONS IN e+ e- ANNIHILATION AT S**(1/2) = 29-GeV

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Badtke, D.H. ; et al.
Phys.Rev.Lett. 53 (1984) 2199, 1984.
Inspire Record 204547 DOI 10.17182/hepdata.20411

Correlations in rapidity space are presented for identified π± and K± in e+e− annihilation at 29-GeV c.m. energy. Short-range KK correlations indicate local flavor compensation in the hadronization process. Long-range KK and ππ correlations prove that the initial partons carry flavor. In addition, we observe significant Kπ correlations as a result of heavy-quark decays.

1 data table

No description provided.