Evidence for Three New Charged Bosons of Masses 1929, 2195 and 2382 MeV and Narrow Widths

Chikovani, G.E. ; Kienzle, W. ; Maglich, B.C. ;
Phys.Lett. 22 (1966) 233-236, 1966.
Inspire Record 50973 DOI 10.17182/hepdata.29841

Three new bosons, referred to as S, T and U, have been observed in the reaction π - + p → p + X - using the missing-mass spectrometer; their masses are 1929, 2195 and 2382 MeV, respectively. Their physical widths are equal to our experimental resolution and compatible with zero-width, with the upper limits: Γ ≤ 35, ≤ 13 and ≤ 30 MeV, respectively. They are produced with the differential cross section d σ/d t between 20 and 40 microbarn per (GeV/ c ) 2 at an average t = 0.3 (GeV/ c ) 2 .

1 data table

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5-GeV - 16-GeV SINGLE pi+ PHOTOPRODUCTION FROM HYDROGEN

Boyarski, A. ; Bulos, F. ; Busza, W. ; et al.
Phys.Rev.Lett. 20 (1968) 300-303, 1968.
Inspire Record 51151 DOI 10.17182/hepdata.21730

The differential cross sections for single-π+ photoproduction from hydrogen have been measured over a range of momentum transfers from -2×10−4 to -2 (GeV/c)2, and photon energies from 5 to 16 GeV. The differential cross section increases by roughly a factor of 2 as the magnitude of the square of the momentum transfer decreases from 0.02 (GeV/c)2. The cross section falls approximately as exp(−3|t|) at large momentum transfers, with a similar momentum-transfer dependence of the cross section at all photon energies studied.

4 data tables

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K+-Meson Production in p-p Collisions at 2.5-3.0 GeV

Hogan, W.J. ; Piroue, P.A. ; Smith, A.J.S. ;
Phys.Rev. 166 (1968) 1472-1481, 1968.
Inspire Record 54415 DOI 10.17182/hepdata.26524

Differential cross sections as a function of momentum are presented for the production of K+ mesons in p−p collisions at incident proton energies of 2.54, 2.88, and 3.03 GeV. The measurements were made at 20°, 30°, and 40° relative to the direction of the internal proton beam of the Princeton-Pennsylvania accelerator. At 2.54 GeV, the results follow closely the predictions from phase space (with 60% K+ΣN and 40% K+Λp in the final state). At 2.88 and 3.03 GeV, however, there is a definite disagreement with phase space. The data are compared to the predictions of three models: (1) a model based on the assumption that K's are produced via p+p→K++X+, where X+ is a B=2, S=−1 resonance which decays into a nucleon+hyperon; (2) the isobar model; and (3) the one-pion-exchange model. Model (1) is found to be inconclusive, model (2) is inadequate, and model (3) is partly successful in predicting total cross sections, but not in interpreting the detailed experimental observations.

7 data tables

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PHOTOPRODUCTION OF pi- delta++ (1236) FROM HYDROGEN FROM 5-GeV TO 16-GeV

Boyarski, A. ; Diebold, Robert E. ; Ecklund, Stanley D. ; et al.
Phys.Rev.Lett. 22 (1969) 148-151, 1969.
Inspire Record 52692 DOI 10.17182/hepdata.21668

The cross section for γp→π−Δ++(1236), measured at 5, 8, 11, and 16 GeV from nearzero momentum transfer to -1 GeV2 (-2 GeV2 at 16 GeV), rises from small t to a maximum near −t=mπ2, then falls as e12t out to −t≈0.2 GeV2, after which it becomes roughly equal in slope and magnitude to the single π+ photoproduction cross section (e3t). At fixed t, the cross section varies as k−2, where k is the laboratory photon energy. The results do not agree well with the simple vector-dominance model.

4 data tables
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RATIO OF pi- TO pi+ PHOTOPRODUCTION FROM DEUTERIUM AT 8-GeV AND 16-GeV

Boyarski, A. ; Diebold, Robert E. ; Ecklund, Stanley D. ; et al.
Phys.Rev.Lett. 21 (1968) 1767-1769, 1968.
Inspire Record 52651 DOI 10.17182/hepdata.21722

We have studied the ratio R=[dσ(γd→π−pp)dt][dσ(γd→π+nn)dt]−1 at 8 and 16 GeV for momentum transfers |t| from about 0.001 to 1.3 GeV2. R is close to unity for |t|<mπ2, but falls very rapidly with increasing |t|, passing through ½ near |t|=0.1 GeV2 and having a minium value of about 13 near |t|=0.4 GeV2; it slowly increases at larger momentum transfers. These results are similar to those obtained in other laboratories at 3.4 and 5 GeV. This implies considerable interference between the isoscalar and isovector photon amplitudes.

2 data tables

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PHOTOPRODUCTION OF K+ LAMBDA AND K+ SIGMA0 FROM HYDROGEN FROM 5-GeV to 16-Gev

Boyarski, A. ; Bulos, F. ; Busza, W. ; et al.
Phys.Rev.Lett. 22 (1969) 1131-1133, 1969.
Inspire Record 54849 DOI 10.17182/hepdata.3394

Cross sections for the reactions γp→K+Λ and γp→K+Σ0 have been measured at squared four-momentum transfer (−t) from 0.005 to 2 GeV2, at photon energies 5, 8, 11, and 16 GeV. For −t>0.2 GeV2 each of the K+ cross sections is about ⅓ of the π+n photoproduction cross section, having nearly the same energy and momentum-transfer dependence. The K+ cross sections fall off at small |t|, however, in contrast to the sharp forward spike seen in π+n; this leads to a disagreement with an SU(3) prediction for −t<0.1 GeV2. The ratio of K+Σ0 to K+Λ cross sections is typically between 0.5 and 1.0.

9 data tables
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SINGLE pi+- AND K+ PHOTOPRODUCTION FROM COMPLEX NUCLEI AT 8-GeV AND 16-GeV

Boyarski, A. ; Diebold, Robert E. ; Ecklund, Stanley D. ; et al.
Phys.Rev.Lett. 23 (1969) 1343-1346, 1969.
Inspire Record 54879 DOI 10.17182/hepdata.21641

The reactions γA→π±A* have been studied at four-momentum transfers −t<~0.5 GeV2 for seven elements ranging from hydrogen to lead. Exclusion-principle suppression is clearly visible at small-momentum transfer. Neither the A dependence nor the energy dependence of the cross sections agrees with the predictions of the vector-dominance model. The ratio of π−π+ production requires equal spatial distributions for the protons and neutrons in nuclei. Some K+ data are also presented.

16 data tables

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PHOTOPRODUCTION OF K+ HYPERON FROM HYDROGEN AND DEUTERIUM AT 11-GeV

Boyarski, A. ; Diebold, Robert E. ; Ecklund, Stanley D. ; et al.
Phys.Lett.B 34 (1971) 547-550, 1971.
Inspire Record 60853 DOI 10.17182/hepdata.5801

Using an 11-GeV bremsstrahlung beam and the SLAC 20-GeV spectrometer, we have measured K + missing mass spectra from hydrogen and deuterium at five angles with momentum transfer squared ranging from 0.025 to 0.46 GeV 2 . Steps in the spectra as a function of missing mass were found corresponding to production of Λ , Σ , Σ 1385 + Λ 1405 and Λ 1520 . The ratio Σ − and Σ 0 production is not consistent with pure isotopic spin 1 2 in the t -channel for the reaction γ N→K + Σ . The cross sections for γ N → K + Σ 1385 compared with γ N→ πΔ violate an SU(3) prediction.

4 data tables

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Pi+ p elastic scattering data between 1820- and 2090-mev center-of-mass energy

Kalmus, G.E. ; Michael, W. ; Birge, R.W. ; et al.
Phys.Rev.D 4 (1971) 676-683, 1971.
Inspire Record 67772 DOI 10.17182/hepdata.3686

Total and differential elastic cross-section data are presented at eight incident π+ momenta: 1.28, 1.34, 1.40, 1.43, 1.55, 1.68, 1.77, and 1.84 GeVc. These data were obtained from a hydrogen-bubble-chamber exposure at the Bevatron, and contain more than 65 000 events. This represents more than 1½ times the world's data hitherto available in this energy region.

9 data tables

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Additional data in the reaction pi+ p ---> sigma+ k+ at 1.28 and 1.41 gev/c and a test of charge independence in the center-of-mass energy range 1.820 to 2.090 gev

Kalmus, G.E. ; Borreani, G. ; Louie, J. ;
Phys.Rev.D 4 (1971) 916-918, 1971.
Inspire Record 67769 DOI 10.17182/hepdata.23075

Data at two additional π+ momenta (1.28 and 1.41 GeVc) in the reaction π+p→Σ+K+ are presented. Charge independence is tested over the c.m. energy range 1.820 to 2.090 GeV; we used our data for the Σ+K+ channel and published data for the π−p→Σ0K0 and Σ−K+ channels.

2 data tables

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