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Measurements of the magnetic form-factor of the proton for timelike momentum transfers

Andreotti, M ; Bagnasco, S ; Baldini, W ; et al.
Phys.Lett.B 559 (2003) 20-25, 2003.
Inspire Record 617594 DOI 10.17182/hepdata.27006

Fermilab experiment E835 has measured the cross section for the reaction p ̄ p→e + e − at s =11.63, 12.43, 14.40 and 18.22 GeV 2 . From the analysis of the 66 observed events new high-precision measurements of the proton magnetic form factor are obtained.

3 data tables
Table 1

The measured cross section in the kinematic range defined by COS(THETA).

Table 2

The proton magnetic form factor calculated assuming the equality of the electric and magnetic form factors.

Table 3

The proton magnetic form factor calculated assuming a negligible electric contribution.


Precise determination of the electromagnetic form-factor of the proton in the timelike region up to s = 4.2-GeV**2

Bardin, G. ; Burgun, G. ; Calabrese, R. ; et al.
Phys.Lett.B 257 (1991) 514-518, 1991.
Inspire Record 314621 DOI 10.17182/hepdata.48504

The s dependence of the proton form factor in the time-like region has been determined up to s =4.2 GeV 2 , assuming the validity of the | G e | = | G m | = | G | hypothesis. Data were taken in a dedicated experiment performed at the LEAR antiproton ring at CERN, increasing by one order of magnitude the available statistics on the proton form factor near threshold in the time-like region. Our result consist of cross section measurements of the p p → e + e − reaction for different beam momenta in the kinematical r 3.6⩽ s ⩽4.2 GeV 2 . The observed s dependence of the form factor close to threshold differs appreciably from the one suggested by previous experiments.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

Results of one-parameter fit. |Ge|=|Gm| assumed.


Determination of the electric and magnetic form-factors of the proton in the timelike region

Bardin, G. ; Burgun, G. ; Calabrese, R. ; et al.
Nucl.Phys.B 411 (1994) 3-32, 1994.
Inspire Record 376134 DOI 10.17182/hepdata.32865

The s dependence of the electromagnetic proton form factors in the time-like region has been determined from the threshold ( s = 4 M p 2 ) up to s = 4.2 GeV 2 . Data were collected in a dedicated experiment performed at the LEAR antiproton ring at CERN, increasing by one order of magnitude the available statistics. Total and differential cross section of the p p → e − e + reaction have been measured. The electric and magnetic form factors are found to have comparable value. The observed form factor shows a clear steep s dependence close to the threshold.

6 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Measurement of the proton electromagnetic form-factors in the timelike region at 8.9-GeV**2 - 13-GeV**2

The E760 collaboration Armstrong, T.A. ; Bettoni, D. ; Bharadwaj, V. ; et al.
Phys.Rev.Lett. 70 (1993) 1212-1215, 1993.
Inspire Record 340584 DOI 10.17182/hepdata.19781

Cross sections for the reaction pp¯→e+e− have been measured at s=8.9,12.4, and 13.0 GeV2. The cross sections have been analyzed to obtain the proton electromagnetic form factors in the timelike region. We find that GM(q2)∝q−4αs2(q2) for q2≥5 (GeV/c)2.

5 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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