HEPData Search

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Neutral Pion Electroproduction in the Resonance Region at High $Q^2$

Villano, A.N. ; Stoler, P. ; Bosted, P.E. ; et al.

Phys.Rev.C 80 (2009) 035203, 2009.

Inspire Record 823260 DOI 10.17182/hepdata.54189

The process $ep \to e^{\prime}p^{\prime}\pi^0$ has been measured at $Q^2$ = 6.4 and 7.7 \ufourmomts in Jefferson Lab's Hall C. Unpolarized differential cross sections are reported in the virtual photon-proton center of mass frame considering the process $\gamma^{\ast}p \to p^{\prime}\pi^0$. Various details relating to the background subtractions, radiative corrections and systematic errors are discussed. The usefulness of the data with regard to the measurement of the electromagnetic properties of the well known $\Delta(1232)$ resonance is covered in detail. Specifically considered are the electromagnetic and scalar-magnetic ratios $R_{EM}$ and $R_{SM}$ along with the magnetic transition form factor $G_M^{\ast}$. It is found that the rapid fall off of the $\Delta(1232)$ contribution continues into this region of momentum transfer and that other resonances

125 data tables match query

Table 1

Differential cross sections at Q**2=6.564 GeV**2, EPSILON=0.4523, W=1.112 GeV and COS(THETA(*))=-0.9 for the small SOS spectrometer.

Table 2

Differential cross sections at Q**2=6.564 GeV**2, EPSILON=0.4523, W=1.112 GeV and COS(THETA(*))=-0.7 for the small SOS spectrometer.

Table 3

Differential cross sections at Q**2=6.564 GeV**2, EPSILON=0.4523, W=1.112 GeV and COS(THETA(*))=-0.5 for the small SOS spectrometer.

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Electroproduction of Eta Mesons in the S11(1535) Resonance Region at High Momentum Transfer

Dalton, M.M. ; Adams, G.S. ; Ahmidouch, A. ; et al.

Phys.Rev.C 80 (2009) 015205, 2009.

Inspire Record 783943 DOI 10.17182/hepdata.50548

The differential cross-section for the process p(e,e'p)eta has been measured at Q2 ~ 5.7 and 7.0 (GeV/c)2 for centre-of-mass energies from threshold to 1.8 GeV, encompassing the S11(1535) resonance, which dominates the channel. This is the highest momentum transfer measurement of this exclusive process to date. The helicity-conserving transition amplitude A_1/2, for the production of the S11(1535) resonance, is extracted from the data. This quantity appears to begin scaling as 1/Q3, a predicted signal of the dominance of perturbative QCD, at Q2 ~ 5 (GeV/c)2.

39 data tables match query

Table 1

Total cross section for the lower Q**2 data as a function of W. The errors are statistics and systematic added in quadrature.

Table 2

Total cross section for the higher Q**2 data as a function of W. The errors are statistics and systematic added in quadrature.

Table 3

Lower Q**2 extracted differential cross section at W = 1.500 GeV and cos(theta(eta) = -0.917, -0.750 and -0.583.

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A Model Independent Second Order Determination of the Strong Coupling Constant $\alpha^- s$

Adeva, B. ; Barber, D.P. ; Becker, U. ; et al.

Phys.Rev.Lett. 50 (1983) 2051, 1983.

Inspire Record 189724 DOI 10.17182/hepdata.3086

With use of the MARK-J detector at s=34.7 GeV 21 000 e+e−→hadron events have been collected. By measurement of the asymmetry in angular energy correlations the strong coupling constant αs=0.13±0.01 (statistical)±0.02 (systematic) is determined, in complete second order, and independent of the fragmentation models and QCD cutoff values used.

1 data table match query

Table 2

No description provided.

Measurement of $e^+ e^- \to \mu^+ \mu^-$ Charge Asymmetry

Adeva, B. ; Barber, D.P. ; Becker, U. ; et al.

Phys.Rev.Lett. 48 (1982) 1701, 1982.

Inspire Record 177308 DOI 10.17182/hepdata.3116

The measurement of the nonelectromagnetic forward-backward charge asymmetry in the reaction e+e−→μ+μ− at s∼34.6 GeV and in the angular region 0<|cosθ|<0.8 is reported. With a systematic error less than 1%, we observe an asymmetry of (-8.1±2.1)%. This is in agreement with the standard electroweak theory prediction of (-7.6±0.6)%. The weak-current coupling constants are also reported.

2 data tables match query

Table 3

No description provided.

Table 4

No description provided.

Measurement of $e^+ e^- \to \mu^+ \mu^-$: A Test of Electroweak Theories

The Mark-J collaboration Adeva, B. ; Becker, U. ; Becker-Szendy, R. ; et al.

Phys.Rev.Lett. 55 (1985) 665, 1985.

Inspire Record 214607 DOI 10.17182/hepdata.3237

We use the reaction e+e−→μ+μ−, in the Mark J detector at the DESY high-energy e+e− collider PETRA, to test the standard electroweak theory and find good agreement. We also set limits on the parameters of several extended gauge theories.

6 data tables match query

Table 1

CROSS SECTION MEASUREMENT RELATIVE TO PREDICTED QED CROSS SECTION.

Table 2

FORWARD-BACKWARD ASYMMETRY. THE SYSTEMATIC ERROR IN THE ASYMMETRY IS <0.5 PCT.

Table 3

ANGULAR DISTRIBUTIONS NOT GIVEN IN PAPER. SUPPLIED BY E.DEFFUR.

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Experimental Study of Electroweak Parameters at {PETRA} Energies (12-{GeV} $< E_{CMS} <$ 36.7-{GeV})

The MARK-J collaboration Barber, D.P. ; Becker, U. ; Bei, G.D. ; et al.

Phys.Rev.Lett. 46 (1981) 1663, 1981.

Inspire Record 164675 DOI 10.17182/hepdata.3303

We have performed a high-statistics measurement of Bhabha scattering and of the production of hadrons in electron-positron annihilation at PETRA energies (12 GeV<~s<~36.7 GeV). Combining the results with measurements of μ+μ− and τ+τ− production enables us to compare our results with electroweak theory. We find sin2θw=0.27±0.08. This is in good agreement with the value obtained from neutrino experiments which were carried out in entirely different kinematic regions.

3 data tables match query

Table 3

ASYMMETRY WAS USED.

Table 4

OVERALL FIT USED.

Table 5

No description provided.

Studies of $\bar{p} p \to \bar{n} n$ and $\bar{n} p$ Annihilation at Incident Momenta of 700-{MeV}/$c$ and 760-{MeV}/$c$

The Bombay-Chandigarh-Jammu-Tokyo collaboration Banerjee, S. ; Ganguli, S.N. ; Gurtu, A. ; et al.

Z.Phys.C 28 (1985) 163, 1985.

Inspire Record 217418 DOI 10.17182/hepdata.1974

Results are presented on the charge exchange reaction$\bar pp \to \bar nn$ and$\bar np$ annihilations from bubble chamber exposures to antiproton beam of momenta 700 and 760 MeV/c. The differential cross section of$\bar pp \to \bar nn$ shows a forward spike followed by a clear dip bump structure. Total annihilation cross section of$\bar np$ for average$\bar n$ momentum of 700 MeV/c has been evaluated to be 55.4±2.2 mb. The multiplicity, Feynmanx andpT2 distributions for inclusive charged pions in$\bar pp$ and$\bar np$ annihilations are found to be similar. The emission of charged pions from$\bar np$ annihilations are found to be consistent with thermodynamic models with temperature ∼110 MeV.

10 data tables match query

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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rivet Analysis
Search for Top Quark and a Test of Models Without Top Quark at the Highest {PETRA} Energies

Adeva, B. ; Barber, D.P. ; Becker, U. ; et al.

Phys.Rev.Lett. 50 (1983) 799, 1983.

Inspire Record 182337 DOI 10.17182/hepdata.20549

With a PETRA energy scan in ≤30-MeV steps, the continuum production of open top quark up to 38.54 GeV is excluded. Over regions of energy scan from 29.90 to 38.63 GeV limits are set on the product of hadronic branching ratio and electronic width BhΓee for toponium to be less than 2.0 keV at the 95% confidence level. By a search for flavor-changing neutral currents in b decay, models without a top quark are excluded.

1 data table match query

Table 4

MEAN VALUES OF R. FIRST ENERGY RANGE IS ACTUALLY 29.90 TO 31.46 AND 33.0 TO 36.72 GEV.

Inclusive Muon Production in $e^+ e^-$ Annihilation with $\sqrt{s}$ = 7.3-GeV

Badtke, D.H. ; Barnett, B.A. ; Jones, L.H. ; et al.

Phys.Rev.Lett. 40 (1978) 827, 1978.

Inspire Record 134548 DOI 10.17182/hepdata.20890

We present results on charged multiplicity nch=2 and nch>2 muon events produced in e+e− collisions with 〈s12〉=7.3 GeV at 90° to the beams. The background-subtracted inclusive cross section for the nch=2 events is 10.2±5.4 pb/sr, in agreement with the expected contribution from the heavy lepton τ. The cross section for the nch>2 events is 19.0±6.5 pb/sr whereas we expect only 2.9 pb/sr from the τ, indicating that we may be seeing the weak decays of charmed mesons.

2 data tables match query

Table 1

No description provided.

Table 2

No description provided.

Measurement of Dimuon Production at the {ISR}

Antreasyan, D. ; Atwood, W. ; Battiston, R. ; et al.

Phys.Rev.Lett. 45 (1980) 863, 1980.

Inspire Record 153857 DOI 10.17182/hepdata.20656

Prompt dimuon production has been measured. Events with mass up to 25 GeV/c2 are observed, as well as the J and ϒ resonances. Cross sections are given for J and ϒ production. For the continuum, the scaling function F(τ) is measured at very small values of τ=ms covering the range 0.05<τ<0.20.

3 data tables match query

Table 1

No description provided.

Table 2

HERE UPSILON = ALL USILON FAMILY. ANGULAR DISTBN. IS SEEN TO BE ISOTROPIC.

Table 3

No description provided.

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Neutral Pion Electroproduction in the Resonance Region at High $Q^2$

Electroproduction of Eta Mesons in the S11(1535) Resonance Region at High Momentum Transfer

A Model Independent Second Order Determination of the Strong Coupling Constant $\alpha^- s$

Measurement of $e^+ e^- \to \mu^+ \mu^-$ Charge Asymmetry

Measurement of $e^+ e^- \to \mu^+ \mu^-$: A Test of Electroweak Theories

Experimental Study of Electroweak Parameters at {PETRA} Energies (12-{GeV} $< E_{CMS} <$ 36.7-{GeV})

Studies of $\bar{p} p \to \bar{n} n$ and $\bar{n} p$ Annihilation at Incident Momenta of 700-{MeV}/$c$ and 760-{MeV}/$c$

rivet Analysis
Search for Top Quark and a Test of Models Without Top Quark at the Highest {PETRA} Energies

Inclusive Muon Production in $e^+ e^-$ Annihilation with $\sqrt{s}$ = 7.3-GeV

Measurement of Dimuon Production at the {ISR}