HEPData Search

Exclusive production of proton-antiproton pairs by two photon scattering at CM energies between 2.0 GeV and 3.1 GeV has been measured with the TASSO detector at the e + e − storage ring PETRA. The angular distribution is flat within the accepted CM angular range | cos Θ ∗ |⩽0.7 . The integrated cross section (| cos Θ ∗ |⩽0.6) drops from about 4 nb at 2 GeV to less than 0.5 nb above 3 GeV. For the two-photon production of the η c (2984) and its subsequent decay into proton-antiproton the upper limit Γ(η c →γγ)· B (η c → p p )<0.32 keV (95% CL) is found.

5 data tables

Table 1

No description provided.

Table 2

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Table 3

UPPER LIMIT FOR THE PRODUCT OF THE ETA/C --> GAMMA GAMMA WIDTH AND THE BRANCHING RATIO OF ETA/C --> P AP IS DETERMINED TO BE 0.32 KEV WITH 90 PCT CL.

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rivet Analysis
>A Measurement of $e^+ e^- \to \bar{p} p$ for 1975-{MeV} $\le \sqrt{s} \le$ 2250-{MeV}

Bisello, D. ; Limentani, S. ; Nigro, M. ; et al.

Nucl.Phys.B 224 (1983) 379, 1983.

Inspire Record 190558 DOI 10.17182/hepdata.33935

The e + e − → p p cross section has been measured in the energy interval (1975 ⩽ 2 E ⩽ 2250) MeV for |cos θ | < 0.7. The measurement is based on ∼ 100 events, thus improving by a factor 3 on the previous existing statistics in this energy interval. The form factor | G | 2 is given as a function of energy under the assumption | G E | = | G M |. We also give the first measurement of the differential cross section, averaged over the energy interval, and estimate the ratio G M |/| G E | from it.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

A STUDY OF DELTA++ AND DELTA0 ISOBAR INCLUSIVE PRODUCTION IN K- p INTERACTIONS AT 32-GeV/c

Babintsev, V.V. ; Bogolyubsky, M.Yu. ; Bumazhnov, V.A. ; et al.

Sov.J.Nucl.Phys. 39 (1984) 414, 1984.

Inspire Record 190556 DOI 10.17182/hepdata.41019

22 data tables

Table 1

No description provided.

Table 2

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Table 3

EVENTS WITH IDENTIFIED PROTONS.

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Electroweak Effects in $e^+ e^- \to \mu^+ \mu^-$ at 29-{GeV}

Fernandez, E. ; Ford, William T. ; Read, Alexander L. ; et al.

Phys.Rev.Lett. 50 (1983) 1238, 1983.

Inspire Record 188749 DOI 10.17182/hepdata.20560

A measurement of the cross section for production of collinear muon pairs based upon a sample of about 3000 events observed in the MAC detector at the storage ring PEP is presented. From the angular asymmetry Aμμ=0.076±0.018 the axial-vector weak neutral coupling is found to be given by gAegAμ=0.31±0.08.

2 data tables

Table 1

Data on non-collinearity and angular distribution.

Table 2

Asymmetry measurement based on extrapolation of number of events to 4 PI acceptance.

MEASUREMENT OF THE SPECTATOR PROTON YIELD AT 0 ANGLE IN THE DEUTERON STRIPPING REACTION ON CARBON AT 8.9-GeV/c. (IN RUSSIAN)

Ableev, V.g. ; Vorobev, G.g. ; Zaporozhets, S.a. ; et al.

Yad.Fiz. 37 (1983) 132-136, 1983.

Inspire Record 192436 DOI 10.17182/hepdata.38079

The invariant cross section of the reaction of deuteron stripping on carbon target has been measured at a deuteron momentum of 8.9 GeV/c. The cross section is obtained at a zero detection angle of the stripping proton: E/p2xd2σ/dpdΩ=(281+-9)xbxGeV/srx(GeV/c)3. This value is consistent with the one calculated in the framework of the Bertocci-Treleani model of deuteron fragmentation. When the method of Nissen-Meyer is used for orthogonalization of the wave functions of primary deuteron and the (np) system, resulting from its disintegration, a similar calculation gives the result, which is 1.4 times larger than the measured value. Distribution in the cosine of angle of proton yield at the fixed proton momentum p turned out to be near to isotropy one and distribution in p at the fixed cos theta has the maximum at p=50 MeV/c

3 data tables

Table 1

Table 2

Table 3

STUDY OF PROTON DIFFRACTIVE EXCITATION PROCESSES IN REACTION K+ p ---> K+ p pi+ pi- AT 32-GeV/c

The Soviet-CERN collaboration Chliapnikov, P.V. ; Falaleev, V.P. ; Garuchava, Z.Sh. ; et al.

Sov.J.Nucl.Phys. 38 (1983) 235, 1983.

Inspire Record 183145 DOI 10.17182/hepdata.41204

None

5 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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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.

4 data tables

Table 1

SEE PRL 55, 665 FOR DISTRIBUTIONS AT 34.6 GEV AND ABOVE.

Table 2

SEE PRL 55, 665 FOR CROSS SECTION VALUES AND FORWARD BACKWARD ASYMMETRY.

Table 3

No description provided.

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CM Energies (GeV)

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A STUDY OF e+ e- ANNIHILATION IN THE 1400-MeV TO 2250-MeV ENERGY RANGE WITH THE MAGNETIC DETECTOR DM2 AT DCI

STUDY OF SPIN ALIGNMENT OF rho0 (770) MESON in K- p AND p p INTERACTIONS AT 32-GeV/c

WEAK NEUTRAL CURRENT EFFECTS IN e+ e- ---> mu+ mu- AT 29-GeV

rivet Analysis
Differential Cross-sections for $\gamma \gamma \to p \bar{p}$ in the Center-of-mass Energy Range From 2.0-{GeV} to 3.1-{GeV}

rivet Analysis
>A Measurement of $e^+ e^- \to \bar{p} p$ for 1975-{MeV} $\le \sqrt{s} \le$ 2250-{MeV}

A STUDY OF DELTA++ AND DELTA0 ISOBAR INCLUSIVE PRODUCTION IN K- p INTERACTIONS AT 32-GeV/c

Electroweak Effects in $e^+ e^- \to \mu^+ \mu^-$ at 29-{GeV}

MEASUREMENT OF THE SPECTATOR PROTON YIELD AT 0 ANGLE IN THE DEUTERON STRIPPING REACTION ON CARBON AT 8.9-GeV/c. (IN RUSSIAN)

STUDY OF PROTON DIFFRACTIVE EXCITATION PROCESSES IN REACTION K+ p ---> K+ p pi+ pi- AT 32-GeV/c

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