On the Possible Existence of a Vector Meson rho(1250)

Conversi, M. ; Paoluzi, L. ; Ceradini, F. ; et al.
Phys.Lett.B 52 (1974) 493-497, 1974.
Inspire Record 98127 DOI 10.17182/hepdata.27922

By combining new results obtained at C.M. energies of 1.2 and 1.3 GeV with previous data obtained at lower energies from the e + e − annihilation process e + e − → π + π − π o π o , we get an indication in favour of the existence of a new vector meson of the ϱ type, ϱ' (1250), the first daughter of the ϱ in the predictions of the Veneziano model. Further results on the annihilation process e + e − → π (1600) → π + π − π + π − are also presented.

1 data table match query

NOTE THAT ABOVE 1.3 GEV, THE CROSS SECTION VALUES ARE CRITICALLY DEPENDENT ON THE ASSUMPTION OF A PHASE SPACE DISTRIBUTION FOR THE FINAL STATE. NOTE ALSO THAT THE RHOPRIME(1600)0 --> RHO EPSILON(700) --> PI+ PI- PI0 PI0 RESONANT CONTRIBUTION HAS BEEN SUBTRACTED OUT. THIS CORRECTION IS GREATEST (25 PCT) AT 1.5 GEV.


Multiplicity in hadron production by e+ e- colliding beams

Ceradini, F. ; Santonico, R. ; Conversi, M. ; et al.
Phys.Lett.B 42 (1972) 501-503, 1972.
Inspire Record 84978 DOI 10.17182/hepdata.28188

The average multiplicities 〈 n c 〉 and 〈n〉, of charged-plus-neutral pions produced in e + e − collisions, have been determined for total center-of-mass energies ranging from 1.2 to 2.4 GeV. No appreciable multiplicity variation is observed over this energy range, where the mean values 〈; n c 〉 = 3.3 +0.3 −0.2 and 〈 n 〉 = 4.4 +0.4 −0.2 are found.

2 data tables match query

No description provided.

VALUES OF R CALCULATED FROM TOTAL CROSS SECTION.


Hadron pair production by electron-positron colliding beams

Barbiellini, G. ; Grilli, M. ; Iarocci, E. ; et al.
Lett.Nuovo Cim. 6S2 (1973) 557-565, 1973.
Inspire Record 86306 DOI 10.17182/hepdata.37335

None

1 data table match query

THIS HADRON PAIR CROSS SECTION PROVIDES ONLY AN UPPER LIMIT TO THE PION FORM FACTOR ABOVE 1.5 GEV SINCE KAON PRODUCTION IS NOT DISTINGUISHED.


Observation of a broad peak in the production of four charged pions by e+ e- collisions around 1.6 gev

Barbarino, G. ; Grilli, M. ; Iarocci, E. ; et al.
Lett.Nuovo Cim. 3 (1972) 689-692, 1972.
Inspire Record 77547 DOI 10.17182/hepdata.37365

None

1 data table match query

STATISTICAL ERRORS ONLY.


Multihadron production in e+ e- collisions at high energy

Grilli, M. ; Iarocci, E. ; Spillantini, P. ; et al.
Nuovo Cim.A 13 (1973) 593-644, 1973.
Inspire Record 87243 DOI 10.17182/hepdata.1179

Multihadron production by electron-positron colliding beams has been investigated for total centre-of-mass energies ranging from 1.2 to 2.4 GeV. The total cross-section, σtot ≡ σ(e+e−→π+π−+ + anything), is of the order of σμμ ≡ σ(e+e−→μ+μ−), with a threshold near 1 GeV. Partial cross-sections for the various channels are also derived. The cross-section of the specific channel e+e−→π+π−π+π− exhibits an energy dependence which is suggestive of a heavier vector meson, ρ' (mρ,≈ 1.6 GeV,Гρ, ≈ 350 Mev), having the same quantum numbers as the ρ-meson. An upper limit is given for the coupling constantfρ′ (fρ′/4π<18, wherefρ′=mρ′2e/gγρ′). Final states withG+ parity are found to be much more abundant than those withG− parity. The average multiplicity (charged plus neutral final-state pions) is found to be betweet 4 and 5 over all the energy range explored.

3 data tables match query

No description provided.

VALUES OF R CALCULATED FROM TOTAL CROSS SECTION.

No description provided.


a_1(1260) dominance in the process e+e- \to 4\pi at energies 1.05--1.38 GeV

The CMD-2 collaboration Akhmetshin, R.R. ; Anashkin, E.V. ; Arpagaus, M. ; et al.
Phys.Lett.B 466 (1999) 392-402, 1999.
Inspire Record 483994 DOI 10.17182/hepdata.50145

First results of the study of the process e+e- \to 4\pi by the CMD-2 collaboration at VEPP-2M are presented for the energy range 1.05--1.38 GeV. Using an integrated luminosity of 5.8 pb^{-1}, energy dependence of the processes e+e- \to \pi^+\pi^- 2\pi^0 and e+e- \to 2\pi^+ 2\pi^- has been measured. Analysis of the differential distributions demonstrates the dominance of the a_1\pi and \omega\pi intermediate states. Upper limits for the contributions of other alternative mechanisms are also placed.

3 data tables match query

Energy dependence of the cross section for the 2PI+ 2PI- final state. Statistical errors only.

Energy dependence of the cross section for the PI+ PI- 2PI0 final state. Statistical errors only.

Energy dependence of the cross section for the OMEGA PI0 final state. Statistical errors only.


The Pion Electromagnetic Form-factor in the Timelike Energy Range 1.35-{GeV} $\le \sqrt{s} \le$ 2.4-{GeV}

The DM2 collaboration Bisello, D. ; Busetto, G. ; Castro, A. ; et al.
Phys.Lett.B 220 (1989) 321-327, 1989.
Inspire Record 267118 DOI 10.17182/hepdata.29829

The e + e − → π + π − cross section has been measured from about 280 events (an order of magnitude more than the previous world statistics) in the energy interval 1.35 ⩽ s ⩽ 2.4 GeV with the DM2 detector at DCI. The pion squared form factor | F π | 2 shows a deep minimum around 1.6 GeV/ c 2 and is better fit under the hypothesis of two ϱ-like resonance ⋍0.25 GeV/ c 2 wide with 1.42 and 1.77 GeV/ c 2 masses.

1 data table match query

Statistical errors only.


INELASTIC ELECTRON PHOTON SCATTERING AT MODERATE FOUR MOMENTUM TRANSFERS

The PLUTO collaboration Berger, Christoph ; Genzel, H. ; Grigull, R. ; et al.
Phys.Lett.B 99 (1981) 287-291, 1981.
Inspire Record 155594 DOI 10.17182/hepdata.27125

We present new high statistics data on hadron production in photon-photon reactions. The data are analyzed in terms of an electron-photon scattering formalism. The dependence of the total cross section of Q 2 , the four-momentum transfer squared of the scattered electron, and on the mass W of the hadronic system is investigated. The data are compared to predictions from Vector-Meson Dominance and the quark model.

1 data table match query

DEPENDENCE ON VISIBLE HADRONIC INVARIANT MASS.


Inclusive K0(s) Production in e+ e- Annihilation at Energies of 3.6-GeV to 5.0-GeV

The PLUTO collaboration Burmester, J. ; Criegee, L. ; Dehne, H.C. ; et al.
Phys.Lett.B 67 (1977) 367-370, 1977.
Inspire Record 118873 DOI 10.17182/hepdata.27568

We have measured the production cross section for K s 0 in e + e − annihilation from 3.6 to 5.0 GeV center of mass energy. A substantial increase of the K s 0 yield is observed around 4 GeV in qualitative agreement with the charm hypothesis.

1 data table match query

No description provided.


The Energy Dependence of Sigma (e+ e- --> Hadrons) in the Total Center-Of-Mass Energy Range 1.2-GeV to 3.0-GeV

Bernardini, M. ; Bollini, D. ; Brunini, P.L. ; et al.
Phys.Lett.B 51 (1974) 200-204, 1974.
Inspire Record 89816 DOI 10.17182/hepdata.27933

We have observed 1085 events of the type e + e − → hadrons, in the total centre-of-mass energy range √ s = 1.2 to 3.0 GeV. The energy dependence of the total annihilation cross-section, parametrized in the form σ ( e + e − → hadrons ) = A · s n , is measured to be n = -(1.54 −0.29 +0.17 ) in the above energy range.

4 data tables match query

RESULTS USING THE (AP P) MODEL WITH PHASE-SPACE CORRECTIONS.

R AS CALCULATED FROM THE TOTAL HADRONIC CROSS SECTION USING THE (AP P) MODEL.

TOTAL CROSS SECTIONS OBTAINED USING THE QUASI-MODEL-INDEPENDENT METHOD ARE TABULATED HERE.

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