Measurement of the Radiative Width of the A(2) (1320) in Two Photon Interactions

The TASSO collaboration Althoff, M. ; Braunschweig, W. ; Gerhards, R. ; et al.
Z.Phys.C 31 (1986) 537, 1986.
Inspire Record 228876 DOI 10.17182/hepdata.15859

The reactione+e−→e+e− A2 (1320) has been observed by detecting the decayA2→π+,π-π0. The two-photon width of theA2 has been measured to be Г(A2→γγ)=(0.09±0.27 (stat)±0.16 (syst)) keV. The cross section σ(γγ→π+,π-π0 has been determined outside theA2 resonance region.

1 data table match query

Data read off a graph.


Search for Two Photon Production of Resonances Decaying Into $K \bar{K}$ and $K \bar{K} \pi$

The TASSO collaboration Althoff, M. ; Braunschweig, W. ; Kirschfink, F.J. ; et al.
Z.Phys.C 29 (1985) 189, 1985.
Inspire Record 220941 DOI 10.17182/hepdata.16018

An analysis of the production ofKS0KS0 andK±Ks0π∓ by two quasi-real photons is presented. The cross section forγγ→K0\(\overline {K^0 } \), which is given for the γγ invariant mass range fromK\(\bar K\) threshold to 2.5 GeV, is dominated by thef′(1525) resonance and an enhancement near theK\(\bar K\) threshold. Upper limits on the product of the two-photon width times the branching ratio intoK\(\bar K\) pairs are given forΘ(1700),h(2030), and ξ(2220). For exclusive two-photon production ofK±Ks0π∓ no significant signal was observed. Upper limits are given on the cross section ofγγ→K+\(\overline {K^0 } \)π− orK−K0π+ between 1.4 and 3.2 GeV and on the product of the γγ width times the branching ratio into theK\(\bar K\)π final states for theηc(2980) and the ι(1440), yieldingΓ(γγ)→i(1440))·BR(i(1440)→K\(\bar K\)π<2.2 keV at 95% C.L.

1 data table match query

Data read from graph.. Corrected for the angular distribution, which is assumed to be sin(theta)**4 for W > 1.14 GeV and isotropic in the first bin.


Production of $K \bar{K}$ Pairs in Photon-photon Collisions and the Excitation of the Tensor Meson F-prime (1515)

The TASSO collaboration Althoff, M. ; Brandelik, R. ; Braunschweig, W. ; et al.
Phys.Lett.B 121 (1983) 216-222, 1983.
Inspire Record 181468 DOI 10.17182/hepdata.30814

We have observed exclusive production of K + K − and K S O K S O pairs and the excitation of the f′(1515) tensor meson in photon-photon collisions. Assuming the f′ to be production in a helicity 2 state, we determine Λ( f ′ → γγ) B( f ′ → K K ) = 0.11 ± 0.02 ± 0.04 keV . The non-strange quark of the f′ is found to be less than 3% (95% CL). For the θ(1640) we derive an upper limit for the product Λ(θ rarr; γγ K K ) < 0.03 keV (95% CL ) .

2 data tables match query

Data read from graph.. Errors are the square roots of the number of events.

Data read from graph.. Errors are the square roots of the number of events.


Measurement of the Two Photon Reaction $\gamma \gamma \to \pi^+ \pi^- \pi^+ \pi^-$ at Large Values of $Q^2$

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 41 (1988) 353-357, 1988.
Inspire Record 250570 DOI 10.17182/hepdata.15557

The process γγ→π+π−π+π− has been investigated in reactions of the typee+e−→e+e−π+π−π+π− in the single tag mode. The range of the four momentum squared of one of the virtual photons was 0.28 GeV2/c2≦Q2≦3.6 GeV2/c2, the average being 〈Q2〉=0.92 GeV2/c2; the other photon was quasi real. The reaction is mainly described by the channels γγ→ρ0ρ0 and γγ→4π (phase space), occuring with about equal probability. TheQ2-dependence of the cross section is in agreement with the ρ form factor.

1 data table match query

Data read from graph.. Additional overall systematic error 25%.


The e+ e- ---> pi+ pi- pi+ pi-, K+ K- pi+ pi-, and K+ K- K+ K- cross sections at center-of-mass energies 0.5-GeV to 4.5-GeV measured with initial-state radiation

The BaBar collaboration Aubert, Bernard ; Barate, R. ; Boutigny, D. ; et al.
Phys.Rev.D 71 (2005) 052001, 2005.
Inspire Record 676691 DOI 10.17182/hepdata.22111

We study the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-\gamma$, with a hard photon radiated from the initial state. About 60,000 fully reconstructed events have been selected from 89 $fb^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective \epem center-of-mass energy, so that these data can be compared with the corresponding direct $e^+e^-$ measurements. From the $4\pi$-mass spectrum, the cross section for the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-$ is measured for center-of-mass energies from 0.6 to 4.5 $GeV/c^2$. The uncertainty in the cross section measurement is typically 5%. We also measure the cross sections for the final states $K^+ K^- \pi^+\pi^-$ and $K^+ K^- K^+ K^-$. We observe the $J/\psi$ in all three final states and measure the corresponding branching fractions. We search for X(3872) in $J/\psi (\to\mu^+\mu^-) \pi^+\pi^-$ and obtain an upper limit on the product of the $e^+e^-$ width of the X(3872) and the branching fraction for $X(3872) \to J/\psi\pi^+\pi^-$.

1 data table match query

Measured PI+ PI- PI+ PI- cross sections. The errors are statistical only.


The e+ e- ---> 3(pi+ pi-), 2(pi+ pi- pi0) and K+ K- 2(pi+ pi-) cross sections at center-of-mass energies from production threshold to 4.5-GeV measured with initial-state radiation

The BaBar collaboration Aubert, Bernard ; Barate, R. ; Boutigny, D. ; et al.
Phys.Rev.D 73 (2006) 052003, 2006.
Inspire Record 709730 DOI 10.17182/hepdata.41843

We study the processes e+ e- --> 3(pi+pi-)gamma, 2(pi+pi-pi0)gamma and K+ K- 2(pi+pi-)gamma, with the photon radiated from the initial state. About 20,000, 33,000 and 4,000 fully reconstructed events, respectively, have been selected from 232 fb-1 of BaBar data. The invariant mass of the hadronic final state defines the effective e+e- center-of-mass energy, so that these data can be compared with the corresponding direct e+e- measurements. From the 3(pi+pi-), 2(pi+pi-pi0) and K+ K- 2(pi+pi-) mass spectra, the cross sections for the processes e+ e- --> 3(pi+pi-), e+ e- --> 2(pi+pi-pi0) and e+ e- --> K+ K- 2(pi+pi-) are measured for center-of-mass energies from production threshold to 4.5 GeV. The uncertainty in the cross section measurement is typically 6-15%. We observe the J/psi in all these final states and measure the corresponding branching fractions.

2 data tables match query

The cross section for E+ E- --> 3PI+ 3PI- as measured with the ISR data. Errors are statistical only.

The cross section for E+ E- --> 2PI+ 2PI- 2PI0 as measured with the ISR data. Errors are statistical only.


The $e^+ e^-\to 2(\pi^+\pi^-)\pi^0$, 2(\pi^+\pi^-)\eta$, $K^+ K^-\pi^+\pi^-\pi^0$ and $K^+ K^-\pi^+\pi^-\eta$ Cross Sections Measured with Initial-State Radiation

The BaBar collaboration Aubert, Bernard ; Bona, M. ; Boutigny, D. ; et al.
Phys.Rev.D 76 (2007) 092005, 2007.
Inspire Record 758568 DOI 10.17182/hepdata.51824

We study the processes $e^+ e^-\to 2(\pi^+\pi^-)\pi^0\gamma$, $2(\pi^+\pi^-)\eta\gamma$, $K^+ K^-\pi^+\pi^-\pi^0\gamma$ and $K^+ K^-\pi^+\pi^-\eta\gamma$ with the hard photon radiated from the initial state. About 20000, 4300, 5500 and 375 fully reconstructed events, respectively, are selected from 232 fb$^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective $e^+ e^-$ center-of-mass energy, so that the obtained cross sections from the threshold to about 5 GeV can be compared with corresponding direct \epem measurements, currently available only for the $\eta\pi^+\pi^-$ and $\omega\pi^+\pi^-$ submodes of the $e^+ e^-\to 2(\pi^+\pi^-)\pi^0$ channel. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from $e^+ e^-\to\omega(782)\pi^+\pi^-$ and study the $\omega(1420)$ and $\omega(1650)$ resonances. In the charmonium region, we observe the $J/\psi$ in all these final states and several intermediate states, as well as the $\psi(2S)$ in some modes, and we measure the corresponding branching fractions.

4 data tables match query

Measured cross section for E+ E- --> 2(PI+ PI-) PI0 with statistical errorsonly.

Measured cross section for E+ E- --> ETA PI+ PI- with statistical errors only.

Measured cross section for E+ E- --> OMEGA PI+ PI- with statistical errors only.

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Measurements of e+ e- ---> K+ K- eta, K+ K- pi0 and K0(s) K+- pi-+ cross- sections using initial state radiation events

The BaBar collaboration Aubert, Bernard ; Bona, M. ; Boutigny, D. ; et al.
Phys.Rev.D 77 (2008) 092002, 2008.
Inspire Record 765258 DOI 10.17182/hepdata.50372

This paper reports measurements of processes: e+e- -> gamma KsK+pi-, e+e- -> gamma K+K-pi0, e+e- -> gamma phi eta, and e+e- -> gamma phi pi0. The initial state radiated photon allows to cover the hadronic final state in the energy range from thresholds up to ~4.6 GeV. The overall size of the data sample analyzed is 232 fb-1, collected by the BaBar detector running at the PEP-II e+e- storage ring. From the Dalitz plot analysis of the KsK+pi- final state, moduli and relative phase of the isoscalar and the isovector components of the e+e- -> K K*(892) cross section are determined. Parameters of phi and rho recurrences are also measured, using a global fitting procedure which exploits the interconnection among amplitudes, moduli and phases of the e+e- -> KsK+pi-, K+K-pi0, phi eta final states. The cross section for the OZI-forbidden process e+e- -> phi pi0, and the J/psi branching fractions to KK*(892) and K+K-eta are also measured.

2 data tables match query

The cross section for E+ E- --> K0S K+ PI- + CC with statistical errors only.

The cross section for E+ E- --> PHI PI0 with statistical errors only.


Total hadronic cross-section of gamma rays in hydrogen in the energy range 0.265-GeV to 4.215-GeV

Armstrong, T.A. ; Hogg, W.R. ; Lewis, G.M. ; et al.
Phys.Rev.D 5 (1972) 1640-1652, 1972.
Inspire Record 67298 DOI 10.17182/hepdata.22462

The total cross section of γ rays in hydrogen resulting in hadron production, σT, has been measured over the energy range 265-4215 MeV. A tagging system with narrow energy bins was employed. Structure in the resonance region followed by a steady fall with energy has been observed and the results are analyzed. The forward amplitude of γ-proton scattering is evaluated, and its behavior in the Argand diagram studied as a function of energy. The relationships of the measurements to Regge-pole theory and the vector-dominance model are detailed.

2 data tables match query

No description provided.

SPIN AVERAGED FORWARD COMPTON SCATTERING AMPLITUDE. IM(AMP) WAS CALCULATED VIA THE OPTICAL THEOREM FROM A SMOOTH FIT TO THE DATA, AND USED IN THE DISPERSION RELATION TO CALCULATE RE(AMP). AT THRESHOLD THE THOMSON AMPLITUDE IS -3.0 MUB*GEV.


Production of Four Prong Final States in Photon-photon Collisions

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Avery, R.E. ; et al.
Phys.Rev.D 37 (1988) 28, 1988.
Inspire Record 261630 DOI 10.17182/hepdata.3824

Results are presented on the exclusive production of four-prong final states in photon-photon collisions from the TPC/Two-Gamma detector at the SLAC e+e− storage ring PEP. Measurement of dE/dx and momentum in the time-projection chamber (TPC) provides identification of the final states 2π+2π−, K+K−π+π−, and 2K+2K−. For two quasireal incident photons, both the 2π+2π− and K+K−π+π− cross sections show a steep rise from threshold to a peak value, followed by a decrease at higher mass. Cross sections for the production of the final states ρ0ρ0, ρ0π+π−, and φπ+π− are presented, together with upper limits for φρ0, φφ, and K*0K¯ *0. The ρ0ρ0 contribution dominates the four-pion cross section at low masses, but falls to nearly zero above 2 GeV. Such behavior is inconsistent with expectations from vector dominance but can be accommodated by four-quark resonance models or by t-channel factorization. Angular distributions for the part of the data dominated by ρ0ρ0 final states are consistent with the production of JP=2+ or 0+ resonances but also with isotropic (nonresonant) production. When one of the virtual photons has mass (mγ2=-Q2≠0), the four-pion cross section is still dominated by ρ0ρ0 at low final-state masses Wγγ and by 2π+2π− at higher mass. Further, the dependence of the cross section on Q2 becomes increasingly flat as Wγγ increases.

2 data tables match query

TAGGED DATA, RESULTS OBTAINED USING TRANSVERSE-TRANSVERSE LUMINOSITY ONLY. DATA FOR Q2=0 ARE FROM UNTAGGED SAMPLE, ERRORS DUE TO RELATIVE NORMALISATION OF THESE SAMPLES IS INCLUDED INTO ERRORS QUOTED.

UNTAGGED DATA.


Tensor Meson Excitation in the Reaction $\gamma \gamma \to K^0_S K^0_S$

The PLUTO collaboration Berger, Christoph ; Genzel, H. ; Lackas, W. ; et al.
Z.Phys.C 37 (1988) 329, 1988.
Inspire Record 250982 DOI 10.17182/hepdata.15690

In the analysis of the reactione+e−→e+e−KS0Ks0 clear evidence for exclusive γγ→f2′ resonance production is observed. The productΓγγ ·B(f2′→K\(\bar K\)) is measured to be 0.10−0.03−0.02+0.04+0.03 keV independent of ana priori assumption on the helicity structure. Our data are consistent with a pure helicity 2 contribution and we derive an upper limit for the ratioΓγγ(0)/Γγγ. The absence of events in the mass region around 1.3 GeV clearly proves destructivef2−a2 interference and allows to measure the relative phases betweenf2,a2 andf2′. Upper limits on the production of the glueball candidate statesf2(1720) andX(2230) as well as theKS0KS0-continuum are given.

1 data table match query

Data read from graph.


Pion and kaon pair production in photon-photon collisions

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Avery, R.E. ; et al.
Phys.Rev.Lett. 57 (1986) 404, 1986.
Inspire Record 228072 DOI 10.17182/hepdata.20204

We report measurements of the two-photon processes e+e−→e+e−π+π− and e+e−→e+e−K+K−, at an e+e− center-of-mass energy of 29 GeV. In the π+π− data a high-statistics analysis of the f(1270) results in a γγ width Γ(γγ→f)=3.2±0.4 keV. The π+π− continuum below the f mass is well described by a QED Born approximation, whereas above the f mass it is consistent with a QCD-model calculation if a large contribution from the f is assumed. For the K+K− data we find agreement of the high-mass continuum with the QCD prediction; limits on f′(1520) and θ(1720) formation are presented.

2 data tables match query

Data read from graph. Additional overall systematic error 20% not included.

Data read from graph. Additional overall systematic error 20% not included.


Observation of Spin Parity 2+ Dominance in the Reaction $\gamma \gamma \to \rho^0 \rho^0$ Near Threshold

The ARGUS collaboration Albrecht, H. ; Ehrlichmann, H. ; Glaser, R. ; et al.
Z.Phys.C 50 (1991) 1-10, 1991.
Inspire Record 296187 DOI 10.17182/hepdata.45136

The reactionγγ→π+π−π+π− has been studied with the ARGUS detector. The rate in the invariant mass region below 1.8 GeV/c2 is found to be largely due toρ0ρ0 production. A spin-parity analysis shows a dominance of the partial wave (JP,Jz)=(2+, 2) with a small admixture fromJP=0+. The contribution of negative parity states is consistent with zero. The large ratio of cross sectionsσ(γγ→ρ0ρ0)/σ(γγ→ρ+ρ−)≃4, and the dominance of theJP=2+ wave in the reactionγγ→ρ0ρ0 is a signature consistent with the production of an exotic (I=2) resonance.

4 data tables match query

Statistical errors only.. Cross-section assuming phase-space distribution, as obtained by a 7 parameter fit.

Statistical errors only.. Cross-section assuming phase-space distribution, as obtained by a 7 parameter fit.

Partial wave components for the (JP,JZ) contribution to RHO0 RHO0 cross section.

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The total pair production cross-section of gamma-rays in hydrogen and deuterium

Rawlinson, W.R. ; Tait, N.R.S. ; Thompson, J.C. ; et al.
Nucl.Phys.B 45 (1972) 41-46, 1972.
Inspire Record 75026 DOI 10.17182/hepdata.32781

The total electromagnetic cross sections of g-rays in hydrogen and deuterium have been measured over the energy range 265–4215 MeV using a photon tagging system. From these measurements, the total pair production cross sections are obtained, and the results are found to be in good agreement with the predictions of Jost, Luttinger and Slotnick.

1 data table match query

Axis error includes +- 1/1 contribution.


The total photon deuteron hadronic cross-section in the energy range 0.265-4.215 gev

Armstrong, T.A. ; Hogg, W.R. ; Lewis, G.M. ; et al.
Nucl.Phys.B 41 (1972) 445-473, 1972.
Inspire Record 75161 DOI 10.17182/hepdata.32884

The total cross section for photoproduction of hadrons on the deutron, σ T d , has been measured for photon energies in the range 0.265–40215 GeV. From this, using results for the photon total cross section, obtained previously with the same apparatus, the neutron total cross section has been determined in the resonance region. The resonant structure is found to be quite different from that for the proton. Thereafter the neutron cross section falls off steadily with energy, and the values obtained are consistently lower than those for the proton. Forward scattering amplitudes have been evaluated for the deuteron.

1 data table match query

RESONANCE REGION. UNSMEARING CORRECTION APPLIED, GLAUBER CORRECTION NEGLIGIBLE.


Measurement of $K^+ K^-$ Production in $\gamma \gamma$ Collisions

The ARGUS collaboration Albrecht, H. ; Glaser, R. ; Harder, G. ; et al.
Z.Phys.C 48 (1990) 183-190, 1990.
Inspire Record 284561 DOI 10.17182/hepdata.15151

The production of charged kaon pairs in two-photon interactions has been studied with the ARGUS detector and the topological cross section has been measured. The γγ-widths and interference parameters have been determined for the tensor mesonsf2 (1270),a2 (1318) andf′2 (1525). The helicity structure assumed for the continuum contribution has a significant effect on the result. Upper limits have been obtained for the γγ-widths of the glueball candidate statesf2 (1720) andX (2230).

3 data tables match query

Data read from graph.. Errors are the square roots of the number of events.

Cross section allowing for spin components JM = 22,20,00. Data read from graph.. Additional overall systematic error 8.4%.

Cross section allowing for spin components JM = 22,00. Data read from graph.. Additional overall systematic error 8.4%.


Measurement and Analysis of the Reaction $\gamma \gamma \to \pi^+ \pi^- \pi^+ \pi^-$

The PLUTO collaboration Berger, Christoph ; Genzel, H. ; Lackas, W. ; et al.
Z.Phys.C 38 (1988) 521, 1988.
Inspire Record 252632 DOI 10.17182/hepdata.1916

We have measured the cross section of four charged pion production in photon-photon interactions in the invariant mass range 1.0≦Wγγ≦3.2 GeV and up toQ2=16 GeV2. For 1.2 GeV≦Wγγ≦1.7 GeV the process is dominated by ρ0ρ0 production with a rapid rise in cross section around 1.2 GeV, well below the nominal ρ0ρ0 threshold. The observed distributions in the two particle masses and in the production and decay angles are well described by an incoherent sum of the phase-space subprocesses γγ →ρ0ρ0, →ρ0π+π−, and →π+π−π+π−. A spin-parity analysis of the ρ0ρ0 system showsJP=2+ to dominate, although 0+ is also possible forWγγ≦1.4 GeV. Negative partity states are excluded.

4 data tables match query

No description provided.

No description provided.

No description provided.

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Study of the Reaction $e^+ e^- \to K^+ K^-$ in the Energy Range 1350 $\le \sqrt{s} \le$ 2400-{MeV}

The DM2 collaboration Bisello, D. ; Busetto, G. ; Castro, A. ; et al.
Z.Phys.C 39 (1988) 13, 1988.
Inspire Record 262690 DOI 10.17182/hepdata.15622

Thee+e−→K+K− cross section has been measured from about 750 events in the energy interval\(1350 \leqq \sqrt s\leqq 2400 MeV\) with the DM2 detector at DCI. TheK± form factor |FF±| cannot be explained by the ρ, ω, ϕ and ρ′(1600). An additional resonant amplitude at 1650 MeV has to be added as suggested by a previous experiment.

1 data table match query

No description provided.


Radiative pi0 photoproduction on protons in the Delta+(1232) region

Schumann, S. ; Boillat, B. ; Downie, E.J. ; et al.
Eur.Phys.J.A 43 (2010) 269-282, 2010.
Inspire Record 843314 DOI 10.17182/hepdata.54377

The reaction gamma p -> p pi0 gamma' has been measured with the Crystal Ball / TAPS detectors using the energy-tagged photon beam at the electron accelerator facility MAMI-B. Energy and angular differential cross sections for the emitted photon gamma' and angular differential cross sections for the pi0 have been determined with high statistics in the energy range of the Delta+(1232) resonance. Cross sections and the ratio of the cross section to the non-radiative process gamma p -> p pi0 are compared to theoretical reaction models, having the anomalous magnetic moment kappa_Delta+ as free parameter. As the shape of the experimental distributions is not reproduced in detail by the model calculations, currently no extraction of kappa_Delta+ is feasible.

2 data tables match query

Total cross section for the background reaction GAMMA P --> P PI0.

Total cross section for the background reaction GAMMA P --> P PI0 PI0.