Debenham, N.C.
Pion-Proton Scattering
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PI- P ELASTIC SCATTERING IN THE REGION OF THE X0 (957.6) THRESHOLD

Moissidis, P.G. ; Sarma, H.N.K. ; Carr, J. ; et al.
Nuovo Cim.A 75 (1983) 123-162, 1983.
Inspire Record 196214 DOI 10.17182/hepdata.8694

We present results from a high-momentum-resolution measurement of the π-p elastic differential and total cross-sections-at values of cos θ* between — 0.60 and 0.85 in the centre-of-mass system and at incident-beam momenta between 1.34GeV/c and 1.49 GeV/c—close to the X0 production threshold. There is no significant enhancement near the X0 production threshold. However, a small effect of ~ 3 standard deviations is present, having mass 1898.8 MeV and width ~5MeV, and appearing at an incident-pion momentum of 1435 MeV/c. In addition, a narrow ~ 5-standard-deviation effect atEc.m.= 1876 MeV appeared at an incident-pion momentum of 1389 MeV/c.

10 data tables
Table 1

No description provided.

Table 2

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Table 3

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Inclusive Production of $\pi^0$, $\K^0$(s), $\Lambda^0$, and Anti-lambda0 in 100-{GeV}/c, 200-{GeV}/c and 360-{GeV}/c $\pi^- p$ Interactions

Biswas, N.N. ; Higgins, P.D. ; Bishop, J.M. ; et al.
Nucl.Phys.B 167 (1980) 41-60, 1980.
Inspire Record 8802 DOI 10.17182/hepdata.34519

Inclusive cross sections for π 0 , K s 0 , Λ 0 and Λ 0 production in 100, 200 and 360 GeV /c π − p interactions are presented and compared with data at other energies. Invariant cross sections for γ, K s 0 , Λ 0 and Λ 0 production are presented in terms of Feynman x , the rapidity y , and transverse momentum squared, p T 2 . A comparison of the observed γ spectrum is made with the spectra computed assuming that the π 0 momentum distribution is identical to that of the observed π + or π − .

4 data tables
Table 1

No description provided.

Table 2

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Table 3

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ELASTIC SCATTERING AND OMEGA MESON PRODUCTION NEAR THE THRESHOLD OF PI- P ---> OMEGA N

Karami, H. ; Carr, J. ; Debenham, N.C. ; et al.
Nucl.Phys.B 154 (1979) 503-518, 1979.
Inspire Record 146573 DOI 10.17182/hepdata.34745

Measurements are reported of the differential cross section for the reaction π − +p→ ω +n from threshold to a final-state c.m. momentum P ∗ of 200 MeV /c . The previously reported fall in total cross section σ/P ∗ below about 100 MeV/ c is again seen. The differential cross section remains close to isotropic over the entire range. A paralle experiment on the variation in the elastic differential cross section across the threshold shows evidence of this threshold. The elastic data cover a range of incident moments from 1010 to 1180 MeV/ c in steps of 5 MeV/ c .

4 data tables
Table 1

CROSS SECTION DEPENDENCE ON FINAL STATE CENTRE OF MASS MOMENTUM.

Table 2

ANGULAR DISTRIBUTIONS ARE ALMOST ISOTROPIC.

Table 3

LEGENDRE POLYNOMIAL COEFFICIENTS NORMALIZED SUCH THAT SIG = 4*PI*LEG(L=0).

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CUSP IN PI- P ELASTIC SCATTERING AT THE ETA THRESHOLD

Sarma, H.N.K. ; Binnie, D.M. ; Carr, J. ; et al.
Nucl.Phys.B 161 (1979) 1-13, 1979.
Inspire Record 147683 DOI 10.17182/hepdata.34612

We present results from a high momentum resolution measurement of the π − p elastic differential cross section near the η production threshold. By analysing the cusp discontinuity in the elastic cross section we deduce the non-spin-flip elastic amplitude and compare it with solutions from phase-shift analyses.

601 data tables
Table 1

No description provided.

Table 2

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Table 3

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Elastic Scattering of pi-, K-, and anti-p from Hydrogen at 8-GeV/c and 16-GeV/c

Russ, J.S. ; Birnbaum, D. ; Edelstein, R.M. ; et al.
Phys.Rev.D 15 (1977) 3139-3154, 1977.
Inspire Record 124704 DOI 10.17182/hepdata.24650

In a single-arm spectrometer experiment, high-precision measurements of dσdt for π−p, K−p, and p¯p elastic scattering have been made at 8 and 16 GeV/c. The π−p data show rich structure at 8 GeV/c, indicative of strong non-Pomeron contributions, while the 16-GeV/c data are much smoother. For −t≳1 (GeV/c)2 there is a strong s dependence while there is very little for −t<1 (GeV/c)2. For p¯p scattering the forward region is smoothly diffractive for −t<0.4 (GeV/c)2 and shows antishrinkage. The exponential slope parameter b is measured to be 12.36 ± 0.04 (GeV/c)−2 at 8 GeV/c and 11.40 ± 0.04 (GeV/c)−2 at 16 GeV/c. The structure near −t=0.6 (GeV/c)2 seen at lower energies is still obvious at 16 GeV/c. The K−p data show some structure at 8 GeV/c, but can be represented adequately by a quadratic exponential form. At 16 GeV/c the K−p angular distribution shows antishrinkage and lies above the 8-GeV/c cross section for 0.11<−t<0.8 (GeV/c)2.

7 data tables
Table 1

No description provided.

Table 2

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Table 3

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Study of omega Production Near Threshold in the Reaction pi- p --> omega n

Keyne, J. ; Binnie, D.M. ; Carr, J. ; et al.
Phys.Rev.D 14 (1976) 28-41, 1976.
Inspire Record 115718 DOI 10.17182/hepdata.24698

We have investigated ω production in the reaction π−p→ωn very close to threshold. The dependence of the mass, width, branching ratio, and cross section upon the final-state c.m. momentum, P*, were studied. The mass and width were independent of P* with values of 782.4 ± 0.5 and 10.22 ± 0.43 MeV, respectively. The branching ratio Γ(ω→π0γ)Γ(ω→π+π−π0) was also constant, having a value of 0.084 ± 0.013. An upper limit of 0.18 was set on the branching ratio Γ(ω→π0π0γ)Γ(ω→π0γ). We observed a rapid fall in the cross section below P*=100 MeV/c. This could not be explained in terms of S-wave production alone, but could be fitted by a resonant P wave plus a noninterfering S wave.

1 data table
Table 1

CROSS SECTION DEPENDENCE ON FINAL STATE CENTRE OF MASS MOMENTUM. TABULATED VALUES TAKEN FROM TABLE 1 OF H. KARAMI ET AL., NP B154, 503 (1979).


Backward pi- p Reactions Between 0.6-GeV/c and 1-GeV/c

Debenham, N.C. ; Binnie, D.M. ; Camilleri, L. ; et al.
Phys.Rev.D 12 (1975) 2545-2556, 1975.
Inspire Record 104820 DOI 10.17182/hepdata.24845

Measurements are reported of the differential cross section for the reaction π−p→π−p,π0n,andηn at three angles close to 180° and for incident momenta in the range 0.6 to 1.0 GeV/c. The three measurements were made simultaneously at 1% intervals of beam momentum. The data on elastic scattering resolve a discrepancy between two earlier experiments. They also show clearly the effect of the opening of the ηn channel. The charge-exchange data show that I-spin bounds are not violated in the kinematic region covered. The ηn data can be adequately described with known s-channel resonances. No evidence for narrow N*'s is seen in any channel.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Search for neutral mesons near 1 gev/c-squared

Binnie, D.M. ; Camilleri, L. ; Carr, J. ; et al.
Phys.Rev.Lett. 32 (1974) 392-395, 1974.
Inspire Record 94572 DOI 10.17182/hepdata.21308

In a study of the missing-mass spectrum near 1 GeV in the reaction π−+p→MM+n at three incident momenta near 2 GeV, we find no evidence for the recently reported narrow neutral mesons at 940, 963, and 1033 MeV.

1 data table
Table 1

No description provided.


Study of narrow mesons near their thresholds

Binnie, D.M. ; Camilleri, L. ; Debenham, N.C. ; et al.
Phys.Rev.D 8 (1973) 2789-2813, 1973.
Inspire Record 93328 DOI 10.17182/hepdata.47579

A novel form of mass spectrometer has been used to measure the masses, widths, and cross sections of the η, ω, X0(958), and φ mesons near their respective thresholds in the reaction π−+p→missingmass+n. The incident momentum is varied in small steps through the threshold while neutrons of a given momentum are detected near zero degrees. The lower limit of the c.m. momentum P* at which measurements have been made ranges from about 50 MeV/c at the φ to about 30 MeV/c at the η. A somewhat low value for the ω mass, 782.3 ± 0.6 MeV, is found. The width of the X0 is < 1.9 MeV (95% confidence level). All four mesons show evidence of S-wave production, with values of σP* of 21.2 ± 1.8, 0.35 ± 0.03, and 0.29 ± 0.06 μb/(MeV/c) for the η, X0, and φ, respectively. A rapid rise in the ω cross section appears to be modified by a final-state interaction. The effect of this rise can probably be seen in some S11 pion-nucleon phase-shift solutions. Evidence is also presented of a sudden drop in the π+π− mass spectrum just above the threshold for the production of a K+K− pair. The paper includes a comprehensive discussion of the method and of the details of the spectrometer.

1 data table
Table 1

CROSS SECTIONS NEAR THRESHOLD.


Direct evidence for the s* meson near the k anti-k threshold

Binnie, D.M. ; Carr, J. ; Debenham, N.C. ; et al.
Phys.Rev.Lett. 31 (1973) 1534-1537, 1973.
Inspire Record 94702 DOI 10.17182/hepdata.48037

We report observation of the S* meson in the reaction π−+p→S*+n. The S* decays into ππ and KK and is seen most clearly in the 2π0 channel. A fit to the data gives a sheet-II pole at 987±7−i(24±7) MeV and a relative coupling gS→KKgS→ππ of 3.8 ± 1.0.

1 data table
Table 1

AT AROUND K+ K- THRESHOLD.


A resolution study of backward $\pi^- p$ reactions between 0.6 and 1.0 GeV/c

Debenham, Nicholas Charles ;
PhD Thesis, Imperial Coll., London, 1973.
Inspire Record 1499121 DOI 10.17182/hepdata.75616

None

312 data tables
Table 1

No description provided.

Table 2

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Table 3

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