HEPData Search

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Scalar-Transverse Separation of Electroproduced K+ Lambda and K+ Sigma0 Final States

Bebek, C.J. ; Browman, A. ; Brown, C.N. ; et al.

Phys.Rev.D 15 (1977) 3082, 1977.

Inspire Record 4932 DOI 10.17182/hepdata.24615

We present evidence for a large scalar contribution to the cross section for the reaction ep→eK+Λ. No evidence for a scalar contribution is found for the reaction ep→eK+Σ0. This is reminiscent of the results for the π+n and π+Δ0 final states.

2 data tables

Table 1

AVERAGED OVER PHI. FOR LOW EPSILON, SOME DEUTERIUM DATA ARE INCLUDED. INCLUDING EARLIER MEASUREMENTS AT HIGH EPSILON.

Table 2

AVERAGED OVER PHI. INCLUDING EARLIER MEASUREMENTS AT HIGHER EPSILON.

Omega-Meson Production by Virtual Photons

Joos, P. ; Ladage, A. ; Meyer, H. ; et al.

Nucl.Phys.B 122 (1977) 365-382, 1977.

Inspire Record 118808 DOI 10.17182/hepdata.35453

Qausi-elastic ω production by ep scattering in the kinematic region 0.3. < Q 2 < 1.4 GeV 2 and 1.7 < W < 2.8 GeV was studied using a streamer chamber at DESY. The production angular distribution for γ V p → ω p has a strong non-peripheral component for W < 2 GeV. The ω production cross section falls by a factor of 4 as W changes from 1.7 to 2.8 GeV. In contrast the cross section for ω production with | t | < 0.5 GeV 2 is W independent between 1.7 and 2.8 GeV and for W > 2.0 GeV consistent in both W and Q 2 dependence with the predictions of a model based on one-pion exchange and diffraction.

5 data tables

Table 1

FOR ALL T-VALUES. THE GAMMA* P TOTAL CROSS SECTION WAS TAKEN FROM A FIT TO THE DATA OF S. STEIN ET AL., PR D12, 1884 (1975). 'PPD'.

Table 2

'PPD'. PERIPHERAL OMEGA PRODUCTION.

Table 3

No description provided.

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Differential Cross-Sections of the Neutral Pion Photoproduction from Hydrogen in the Energy Range Between 400-MeV and 950-MeV

Yoshioka, M. ; Noda, A. ; Daigo, M. ; et al.

INS-281, 1977.

Inspire Record 118722 DOI 10.17182/hepdata.40545

None

28 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Phi Production in pi- p Collisions Near Threshold

Courant, H. ; Makdisi, Y.I. ; Marshak, M.L. ; et al.

Phys.Rev.D 16 (1977) 1-6, 1977.

Inspire Record 125080 DOI 10.17182/hepdata.24607

Using a secondary pion beam from the Argonne Zero Gradient Synchrotron we have studied the process π−p→φn in the region of the cross-section enhancement near kinematic threshold. For incident momenta between 1.6 and 2 GeV/c, we have determined production and decay angular distributions and extrapolated total cross sections from a sample of about 160 φ's above background. The production and decay distributions are consistent with isotropy over this entire incident-momentum range. The extrapolated total cross section varies between 19 and 25 μb.

2 data tables

Table 1

Axis error includes +- 16/16 contribution (RES-DEF(RES=PHI,BACK=CORRECTED)).

Table 2

Axis error includes +- 16/16 contribution (RES-DEF(RES=PHI,BACK=CORRECTED)).

Scalar Transverse Separation for Single pi+ Electroproduction

Bebek, C.J. ; Browman, A. ; Brown, C.N. ; et al.

Phys.Rev.Lett. 37 (1976) 1326, 1976.

Inspire Record 110318 DOI 10.17182/hepdata.21075

We report measurements of the exclusive electroproduction reaction e+p→e+π++n for pions produced near 0° in the virtual-photon-proton center-of-mass system with values of ε in the range 0.35<ε<0.45. Combination with data taken at ε near 1 allows us to separate the contributions from transversely polarized and scalar photons in the range 1.2 GeV2<Q2<3.3 GeV2.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

Differential Cross-Sections for the pi0 Photoproduction at Theta (CM) = 90-Degrees and K (Lab) = 380-MeV-820-MeV

Jung, M. ; Kattein, J. ; Leu, P. ; et al.

BONN-HE-76-15, 1976.

Inspire Record 111677 DOI 10.17182/hepdata.50235

None

1 data table

Table 1

No description provided.

Rho Production by Virtual Photons

Joos, P. ; Ladage, A. ; Meyer, H. ; et al.

Nucl.Phys.B 113 (1976) 53-92, 1976.

Inspire Record 108749 DOI 10.17182/hepdata.35708

The reaction γ V p → p π + π − was studied in the W , Q 2 region 1.3–2.8 GeV, 0.3–1.4 GeV 2 using the streamer chamber at DESY. A detailed analysis of rho production via γ V p→ ϱ 0 p is presented. Near threshold rho production has peripheral and non-peripheral contributions of comparable magnitude. At higher energies ( W > 2 GeV) the peripheral component is dominant. The Q 2 dependence of σ ( γ V p→ ϱ 0 p) follows that of the rho propagator as predicted by VDM. The slope of d σ /d t at 〈 Q 2 〉 = 0.4 and 0.8 GeV 2 is within errors equal to its value at Q 2 = 0. The overall shape of the ϱ 0 is t dependent as in photoproduction, but is independent of Q 2 . The decay angular distribution shows that longitudinal rhos dominate in the threshold region. At higher energies transverse rhos are dominant. Rho production by transverse photons proceeds almost exclusively by natural parity exchange, σ T N ⩾ (0.83 ± 0.06) σ T for 2.2 < W < 2.8 GeV. The s -channel helicity-flip amplitudes are small compared to non-flip amplitudes. The ratio R = σ L / σ T was determined assuming s -channel helicity conservation. We find R = ξ 2 Q 2 / M ϱ 2 with ξ 2 ≈ 0.4 for 〈 W 〉 = 2.45 GeV. Interference between rho production amplitudes from longitudinal and transverse photons is observed. With increasing energy the phase between the two amplitudes decreases. The observed features of rho electroproduction are consistent with a dominantly diffractive production mechanism for W > 2 GeV.

10 data tables

Table 1

DIPION CHANNEL CROSS SECTION.

Table 2

THE TOTAL CROSS SECTION WAS OBTAINED BY THE AUTHORS FROM A FIT TO THE SINGLE ARM DATA OF S. STEIN ET AL., PR D12, 1884 (1975).

Table 3

No description provided.

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Photoproduction of Charged pi Mesons from Hydrogen and Deuterium in the Energy Range Between 250-MeV and 790-MeV

Fujii, T. ; Kondo, T. ; Takasaki, F. ; et al.

Nucl.Phys.B 120 (1977) 395-422, 1977.

Inspire Record 108476 DOI 10.17182/hepdata.8405

The differential cross sections for γ p→ π + n from hydrogen and the π − π + ratios from deuterium were measured at nine c.m. angles between 30° and 150° for laboratory photon energies between 260 and 800 MeV. A magnetic spectrometer with three layers of scintillation hodoscope was used to detect charged π mesons. The cross section for γ n→ π − p was obtained as a product of d σ d Ω (γ p →π + n ) and the π − π + ratio. The overall features in the cross sections of the two reactions, γ p→ π + n and γ n→ π − p, and in the ratios, π − π + , agree with predictions by Moorhouse, Oberlack and Rosenfeld, and Metcalf and Walker. An investigation of the possible existence of an isotensor current was made and a negative result was found. In detailed balance comparison with the new results on the inverse reaction π − p→ γ n, no apparent violation of time-reversal invariance was observed.

112 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Observation of a DIP-Bump Structure in Differential Cross-Section for anti-p + p --> anti-N + n in the 700-MeV/c to 760-MeV/c Momentum Range

Bogdanski, M. ; Emura, T. ; Ganguli, S.N. ; et al.

Phys.Lett.B 62 (1976) 117-120, 1976.

Inspire Record 109019 DOI 10.17182/hepdata.27664

Based on a sample of about 3500 events, we have measured the total and differential cross sections of p p → n n in the 700–760 MeV/ c incident momentum region. It is found that σ CE = 10.7 ± 0.2 mb at the average momentum of 730 MeV/ c . The differential angular distribution is characterised by a sharp peak and a dip in the forward direction followed by a secondary maximum. The position of the dip corresponds to | t | ≈ m π 2 . These results are compared with the predictions of the model of Bryan-Phillips. On the other hand, this dip-bump structure can be well understood on a simple picture involving a π exchange and a constant background (for | t | ≲ 3 m π 2 ).

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.