Aihara, H.
[1.0, 2.0]
Max results
Sort by Reverse order

Showing 10 of 331 results

Date

Search for Narrow Peaks in Inclusive $\pi^0$ Spectra From $\bar{p} p$ Annihilation at Rest

The Fukui-Tokyo-KEK-Kyoto Sangyo-Osaka-Tokyo Metropolitan collaboration Chiba, M. ; Doi, K. ; Fujitani, T. ; et al.
Phys.Lett.B 202 (1988) 447-452, 1988.
Inspire Record 252965 DOI 10.17182/hepdata.38510

By using modularized NaI(Tl) detectors, we carried out a high statistics measurement of inclusive π 0 spectra from p p annihilation at rest. We did not observe any narrow π 0 peaks arising from baryonium production, p p →π 0 B . The σ upper limit of the yield varied between 10 −2 and 10 −4 depending on the mass and oncharge multiplicity. Three narrow peaks at 2 σ levels were seen at approximately the same masses as in the previous measurement of p p → γ B .We also derived the yield of p p annihilation into π 0 M for M = ø , η ′, ω , ϱ 0 , η and π 0 .

1 data table
Table 1

No description provided.


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.

12 data tables
Table 1

Fractions of subprocesses from 3-parameter fit to the no-tag data.

Table 2

Fractions of subprocesses from 2-parameter fit to the no-tag data in limited energy range. The Q=1R contribution is set equal to zero.

Table 3

Fractions of subprocesses from 3-parameter fit to the single-tag data.

More…

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
Table 1

Data read from graph.


Determination of the Real Part of the Isospin Even Forward Scattering Amplitude of Pion Nucleon Scattering at 55-{MeV} as a Test of Low-energy Quantum Chromodynamics

Wiedner, U. ; Goring, K. ; Jaki, J. ; et al.
Phys.Rev.Lett. 58 (1987) 648-650, 1987.
Inspire Record 246624 DOI 10.17182/hepdata.20153

The real part of the isospin-even forward-scattering amplitude of pion-nucleon scattering has been determined at a pion energy of Tπ=55 MeV by measurement of the elastic scattering of positive and negative pions on protons within the Coulomb-nuclear interference region. The value confirms the prediction of the Karlsruhe-Helsinki phase-shift analysis for that energy. These phases have been used to determine the σ term of pion-nucleon scattering by means of dispersion relations, resulting in a value for σ which is in contradiction with chiral perturbation theory of QCD.

1 data table
Table 1

PI- P cross sections normalised to the Coulomb cross section taken from the Karlesruhe-Helsinki phase shift analysis (R. Koch, E. Pietarinen (NP A336(80)331).


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.

2 data tables
Table 1

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

Table 2

Data read from graph.. Additional overall systematic error 25%.. The Q**2 approx 0 datum is deduced from the earlier TASSO paper, Brandelik et al, Phys. Lett. 97B(1980)448, (<a href=http://durpdg.dur.ac.uk/scripts/reacsearch.csh/TESTREAC/red+1151> RED = 1151 </a>) on rho0 rho0 production.


rivet Analysis
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
Table 1

Data read off a graph.


rivet Analysis
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.

5 data tables
Table 1

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

Table 2

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

Table 3

Data read from graph.. Additional overall systematic error 20% not included.. The Q**2 dependence is normalized to unity for the bin centred on Q**2 = 0.

More…

Vector Meson Production in the Final State $K^+ K^- \pi^+ \pi^-$ Photon-photon Collisions

The TASSO collaboration Althoff, M. ; Braunschweig, W. ; Gerhards, R. ; et al.
Z.Phys.C 32 (1986) 11, 1986.
Inspire Record 228250 DOI 10.17182/hepdata.15846

Vector meson production is studied in the reaction γγ→K+K−π+π−. A clear Φ(1020) signal is seen in theK+K− mass distribution and aK*0 (890) signal is visible in theK±π∓ one. Both do not seem to be strongly correlated with quasi two body final states. Cross sections for the processes γγ→K+K−π+π−, γγ→Φπ+π−, γγ→K+0K±π∓ and upper limits for the production of Φp, ΦΦ andK*0\(\overline {K^{ * 0} } \) are given as function of the invariant γγ mass.

5 data tables
Table 1

No description provided.

Table 2

First data point is sum of (K* K PI) and (K* AK*).

Table 3

Non resonant phase space.

More…

Measurement of the $\bar{p} p \to \bar{n} n$ Cross-section at Low $\bar{p}$ Momenta

Bruckner, W. ; Dobbeling, H. ; Guttner, F. ; et al.
Phys.Lett.B 169 (1986) 302-308, 1986.
Inspire Record 219986 DOI 10.17182/hepdata.30264

First measurements of the differential cross section are presented for p ̄ p → n ̄ n at LEAR in the momentum range between 180 and 600 MeV/ c . The differential cross sections show a forward peaking followed by a smooth drop-off. No indication of the “bump-dip” structure reported at higher momenta has been observed. The angle-integrated charge-exchange cross sections are determined down to E n ̄ n cm = 6.6 MeV .

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Anti-proton - Proton Elastic Cross-sections in the Momentum Range Between 180-{MeV}/$c$ and 600-{MeV}/$c$

Bruckner, W. ; Dobbeling, H. ; Guttner, F. ; et al.
Phys.Lett.B 166 (1986) 113-118, 1986.
Inspire Record 217928 DOI 10.17182/hepdata.30308

Differential cross sections for p̄p elastic scattering have been measured in the full angular range for the p̄ momenta between 180 and 600 MeV/ c . It is found that s- and p-wave scattering is dominant below 300 MeV/ c . The s-wave component in the total cross section is 40–60% below 300 MeV/ c , in contrast to the NN scattering where it is about 90%. The s-, p- and d-wave scattering amplitudes are derived.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.