OBSERVATION OF ANOMALOUS PRODUCTION OF MUON PAIRS IN e+ e- ANNIHILATION INTO FOUR LEPTON FINAL STATES

The AMY collaboration Ho, Y.H. ; Kurihara, Y. ; Omori, T. ; et al.
Phys.Lett.B 244 (1990) 573-579, 1990.
Inspire Record 294829 DOI 10.17182/hepdata.51362

We report results of a study of four-lepton final states produced in e + e − collisions at center-of-mass energies from 50 to 61.4 GeV using the AMY detector at the TRISTAN collider. For the cases where two or three charged tracks are produced at large angles relative to the beam direction, the cross sections agree with QED. However, we observe an excess of e + e − → e + e − μ + μ − events with four tracks at wide angles and with dimuon mass less than 1.0 GeV / c 2 .

1 data table

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Multiplicity, Momentum and Angular Characteristics of $\pi^-$ Mesons for $p$ C, $d$ C, $\alpha$ C and C C Interactions at 4.2-{GeV}/$c$ Per Nucleon

The Alma Ata-Baku-Belgrade-Bucharest-Dubna-Kishinev-Leipzig- Moscow-Prague-Samarkand-Sofiya-Tashkent-Tbilisi-Ulan Bator-Varna collaboration Agakishiev, G.N. ; Akhababian, N. ; Armutliisky, D. ; et al.
Z.Phys.C 27 (1985) 177, 1984.
Inspire Record 203342 DOI 10.17182/hepdata.1999

Light ion collisions with carbon target at 4.2 GeV/c/N are studied. Pion multiplicity distributions, momentum and angular spectra are analysed. These data are described in terms of models assuming independent interactions of nucleons from the projectile nucleus with the target.

18 data tables

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$\gamma$ and $\pi^0$ Production in $\bar{p} p$ Interactions at 22.4-{GeV}/$c$

The Dubna-Alma Ata-Helsinki-Moscow-Prague-Tbilisi collaboration Batyunya, B.V. ; Boguslavsky, I.V. ; Gramenitsky, I.M. ; et al.
Sov.J.Nucl.Phys. 32 (1980) 684, 1980.
Inspire Record 154051 DOI 10.17182/hepdata.18075

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17 data tables

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On the role of rescattering in the production of particles with large transverse momentum in pi- A interactions at 38-GeV/c.

The RISK collaboration Akhobadze, K.G. ; Bannikov, A.V. ; Boos, E.G. ; et al.
Sov.J.Nucl.Phys. 52 (1990) 662-665, 1990.
Inspire Record 299247 DOI 10.17182/hepdata.17239

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6 data tables

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PT(P=3,NAME=OUT)**2 - MEAN SQUARE OF THE PROJECTION OF THE ASSOCIATED PARTICLE TRANSVERSE MOMENTUM ONTO THE NORMAL TO THE TRIGGER PARTICLE PRODUCTION PLANE.

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Jet Production and Fragmentation in e+ e- Annihilation at 12-GeV to 43-GeV

The TASSO collaboration Althoff, M. ; Braunschweig, W. ; Kirschfink, F.J. ; et al.
Z.Phys.C 22 (1984) 307-340, 1984.
Inspire Record 195333 DOI 10.17182/hepdata.16272

We present the general properties of jets produced bye+e− annihilation. Their production and fragmentation characteristics have been studied with charged particles for c.m. energies between 12 and 43 GeV. In this energy rangee+e− annihilation into hadrons is dominated by pair production of the five quarksu, d, s, c andb. In addition, hard gluon bremsstrahlung effects which are invisible at low energies become prominent at the high energies. The observed multiplicity distributions deviate from a Poisson distribution. The multiplicity distributions for the overall event as well as for each event hemisphere satisfy KNO scaling to within ∼20%. The distributions ofxp=2p/W are presented; scale breaking is observed at the level of 25%. The quantityxpdδ/dxp is compared with multigluon emission calculations which predict a Gaussian distribution in terms of ln(1/x). The observed energy dependence of the maximum of the distributions is in qualitative agreement with the calculations. Particle production is analysed with respect to the jet axis and longitudinal and transverse momentum spectra are presented. The angular distribution of the jet axis strongly supports the idea of predominant spin 1/2 quark pair production. The particle distributions with respect to the event plane show clearly the growing importance of planar events with increasing c.m. energies. They also exclude the presence of heavy quark production,e+e−→Q\(\bar Q\) for quark masses up to 5<mQ<20.3 GeV (|eQ|=2/3) and 7<mQ<19 GeV (|eQ|=1/3). The comparison of 1/σtotdδ/dpT measured at 14, 22 and 34 GeV suggests that hard gluon bremsstrahlung contributes mainly to transverse momenta larger than 0.5 GeV/c. The rapidity distribution forW≧22 GeV shows an enhancement away fromy=0 which corresponds to an increase in yield of 10–15% compared to the centre region (y=0). The enhancement probably results from heavy quark production and gluon bremsstrahlung. The particle flux around the jet axis shows with increasing c.m. energy a rapidly growing number of particles collimated around the jet axis, while at large angles to the jet axis almost noW dependence is observed. For fixed longitudinal momentump‖ approximate “fan invariance” is seen: The shape of the angular distribution around the jet axis is almost independent ofW. The collimation depends strongly onp‖. For smallp‖,p‖<0.2 GeV/c, isotropy is observed. With increasingp‖ the particles tend to be emitted closer and closer to the jet axis.

14 data tables

R VALUES BELOW 32.5 GEV ARE IDENTICAL TO THOSE GIVEN IN BRANDELIK ET AL., PL 113B, 499 (1982).

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CHARGED PARTICLE MULTIPLICITY DISTRIBUTIONS.

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Comparative Characteristics of Central and Noncentral C C Interactions at 4.2-{GeV} Per Nucleon

Agakishiev, G.N. ; Backovic, S. ; Boldea, V. ; et al.
Sov.J.Nucl.Phys. 51 (1990) 481-485, 1990.
Inspire Record 285507 DOI 10.17182/hepdata.17258

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5 data tables

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P - IS PROTON-PARTICIPANTS, ITS NUMBER WAS DEFINED AS FOLLOWS: N(P)=N+ - N - N(S,P) - N(S,T), WHERE N+ , N- - NUMBER OF MULT(CHARGED) PARTICLES WITH Z=+1 AND Z=-1, N(S,P), N(S,T) - NUMBER OF STRIPPING PARTICLES WITH Z=1 FROM PROJECTILE (P>3 GEV, THETA<4 DEG) AND TARGET (P<0.3 GEV FOR PROTONS).

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The Reaction d (polarized) p ---> He-3 pi0 near threshold

Nikulin, V.N. ; Boudard, A. ; Clajus, M. ; et al.
Phys.Rev.C 54 (1996) 1732-1740, 1996.
Inspire Record 421018 DOI 10.17182/hepdata.25833

Angular distributions for the differential cross section and three deuteron analyzing powers iT11, T20, and T22 of the reaction d→p→3Heπ0 have been measured over the whole angular domain at 20 energies close to threshold (0.03<Tπc.m.<10.2 MeV). The differential cross section and tensor analyzing power T20 both show strong variation in energy and angle due to interference between S- and P-wave pion production, whereas iT11 and T22 remain consistent with zero over the whole experimental range. All the data at different energies and angles fall on universal curves when plotted as functions of the single variable pπcosΘ, evaluated in the c.m. The broad features of the results are in line with theoretical expectations. © 1996 The American Physical Society.

1 data table

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Inclusive spectra of pi- mesons with cumulative number n(c) > 0.35 produced in d C, He C, and C C interactions at 4.2-GeV/c per nucleon.

Baatar, Ts. ; Batsaikhan, Ts. ; Ivanovskaya, I.A. ; et al.
Sov.J.Nucl.Phys. 53 (1991) 292-296, 1991.
Inspire Record 295859 DOI 10.17182/hepdata.38726

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2 data tables

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THE STUDY OF p C INTERACTIONS AT p (p) = 10-GeV/c WITH THE EMISSION OF CUMULATIVE DEUTERONS

Armutliisky, D. ; Kopylova, D.K. ; Lyubimov, V.B. ; et al.
Sov.J.Nucl.Phys. 48 (1988) 294, 1988.
Inspire Record 250949 DOI 10.17182/hepdata.38920

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8 data tables

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ALL NEGATIVE PARTICLES WAS CONSIDERED AS PI-.

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