Bose-Einstein correlations in the hadronic decays of the Z0^0

none544Bose-Einstein correlations between pairs of like-sign charged particles produced in e+e- annihilations near the Z0 peak have been studied using data taken with the DELPHI detector at LEP. An enhancement is found in the production of pairs of identical pions of similar momenta, with respect to a reference sample. Under the hypothesis that the pions are emitted by a spherically symmetrical source with gaussian density, the data indicate a radius of the source of r = 0.62 +/- 0.04(stat.) +/- 0.20(syst.) fm. The large systematic uncertainty reflects the sensitivity of r to the choice of the reference sample.noneP. ABREU;W. ADAM;T. ADYE;E. AGASI;G. D. ALEKSEEV;P. ALLEN;S. ALMEHED;S. J. ALVSVAAG;U. AMALDI;E. G. ANASSONTZIS;A. ANDREAZZA;P. ANTILOGUS;W. D. APEL;R. J. APSIMON;B. ASMAN;J. E. AUGUSTIN;A. AUGUSTINUS;P. BAILLON;P. BAMBADE;F. BARAO;R. BARATE;G. BARBIELLINI;D. Y. BARDIN;A. BARONCELLI;O. BARRING;J. A. BARRIO;W. BARTL;M. J. BATES;M. BATTAGLIA;M. BAUBILLIER;K. H. BECKS;C. J. BEESTON;M. BEGALLI;P. BEILLIERE;Y. BELOKOPYTOV;P. BELTRAN;D. BENEDIC;M. BERGGREN;D. BERTRAND;F. BIANCHI;M. S. BILENKY;P. BILLOIR;J. BJARNE;D. BLOCH;S. BLYTH;V. BOCCI;P. N. BOGOLUBOV;T. BOLOGNESE;M. BONESINI;W. BONIVENTO;P. S. L.;P. BORGEAUD;G. BORISOV;H. BORNER;C. BOSIO;B. BOSTJANCIC;S. BOSWORTH;O. BOTNER;B. BOUQUET;C. BOURDARIOS;T. J. V.;M. BOZZO;S. BRAIBANT;P. BRANCHINI;K. D. BRAND;R. A. BRENNER;H. BRIAND;C. BRICMAN;R. C. A.;N. BRUMMER;J. M. BRUNET;L. BUGGE;T. BURAN;H. BURMEISTER;J. A. M.;M. CACCIA;M. CALVI;A. J. C.;T. CAMPORESI;V. CANALE;F. CAO;F. CARENA;L. CARROLL;C. CASO;E. CASTELLI;M. V. C.;A. CATTAI;F. R. CAVALLO;L. CERRITO;V. CHABAUD;A. CHAN;M. CHAPKIN;P. CHARPENTIER;L. CHAUSSARD;J. CHAUVEAU;P. CHECCHIA;G. A. CHELKOV;L. CHEVALIER;P. CHLIAPNIKOV;V. CHOROWICZ;J. T. M.;R. CIRIO;M. P. CLARA;P. COLLINS;J. L. CONTRERAS;R. CONTRI;E. CORTINA;G. COSME;F. COUCHOT;H. B. CRAWLEY;D. CRENNELL;G. CROSETTI;M. CROZON;J. C. MAESTRO;S. CZELLAR;S. DAGORET;E. DAHLJENSEN;B. DALMAGNE;M. DAM;G. DAMGAARD;G. DARBO;E. DAUBIE;A. DAUM;P. D. DAUNCEY;M. DAVENPORT;P. DAVID;W. DASILVA;C. DEFOIX;D. DELIKARIS;B. A. DELLARICCIA;S. DELORME;P. DELPIERRE;N. DEMARIA;A. DEANGELIS;M. DEBEER;H. DEBOECK;W. DEBOER;C. DECLERCQ;M. D. M.;N. DEGROOT;C. DELAVAISSIERE;B. DELOTTO;A. DEMIN;H. DIJKSTRA;L. DICIACCIO;F. DJAMA;J. DOLBEAU;M. DONSZELMANN;K. DOROBA;M. DRACOS;J. DREES;M. DRIS;Y. DUFOUR;L. O. EEK;P. A. M.;R. EHRET;T. EKELOF;G. EKSPONG;A. E. PEISERT;J. P. ENGEL;D. FASSOULIOTIS;T. A. FEARNLEY;M. FEINDT;M. F. ALONSO;A. FERRER;T. A. FILIPPAS;A. FIRESTONE;H. FOETH;E. FOKITIS;F. FONTANELLI;K. A. J.;B. FRANEK;P. FRENKIEL;D. C. FRIES;A. G. FRODESEN;R. FRUHWIRTH;F. FULDAQUENZER;K. FURNIVAL;H. FURSTENAU;J. FUSTER;G. GALEAZZI;D. GAMBA;C. GARCIA;J. GARCIA;C. GASPAR;U. GASPARINI;P. GAVILLET;E. N. GAZIS;J. P. GERBER;P. GIACOMELLI;R. GOKIELI;V. M. GOLOVATYUK;J. J. G.;A. GOOBAR;G. GOPAL;M. GORSKI;V. GRACCO;A. GRANT;F. GRARD;E. GRAZIANI;G. GROSDIDIER;E. GROSS;P. GROSSEWIESMANN;B. GROSSETETE;J. GUY;U. HAEDINGER;F. HAHN;M. HAHN;S. HAIDER;Z. HAJDUK;A. HAKANSSON;A. HALLGREN;K. HAMACHER;G. H. DEMONCHENAULT;W. HAO;F. J. HARRIS;T. HENKES;J. J. HERNANDEZ;P. HERQUET;H. HERR;T. L. HESSING;I. HIETANEN;C. O. HIGGINS;E. HIGON;H. J. HILKE;S. D. HODGSON;T. HOFMOKL;R. HOLMES;S. O. HOLMGREN;D. HOLTHUIZEN;P. F. HONORE;J. E. HOOPER;M. HOULDEN;J. HRUBEC;P. O. HULTH;K. HULTQVIST;P. IOANNOU;D. ISENHOWER;P. S. IVERSEN;J. N. JACKSON;P. JALOCHA;G. JARLSKOG;P. JARRY;B. JEANMARIE;E. K. JOHANSSON;D. JOHNSON;M. JONKER;L. JONSSON;P. JUILLOT;G. KALKANIS;G. KALMUS;F. KAPUSTA;M. KARLSSON;E. KARVELAS;S. KATSANEVAS;E. C. KATSOUFIS;R. KERANEN;J. KESTEMAN;B. A. KHOMENKO;N. N. KHOVANSKI;B. KING;N. J. KJAER;H. KLEIN;W. KLEMPT;A. KLOVNING;P. KLUIT;J. H. KOEHNE;B. KOENE;P. KOKKINIAS;M. KOPF;K. KORCYL;A. V. KORYTOV;V. KOSTIOUKHINE;C. KOURKOUMELIS;O. KOUZNETSOV;P. H. KRAMER;J. KROLIKOWSKI;I. KRONKVIST;J. KRSTIC;U. KRUENERMARQUIS;W. KRUPINSKI;K. KULKA;K. KURVINEN;C. LACASTA;C. LAMBROPOULOS;J. W. LAMSA;L. LANCERI;V. LAPIN;J. P. LAUGIER;R. LAUHAKANGAS;G. LEDER;F. LEDROIT;R. LEITNER;Y. LEMOIGNE;J. LEMONNE;G. LENZEN;V. LEPELTIER;A. LETESSIERSELVON;J. M. LEVY;E. LIEB;D. LIKO;E. LILLETHUN;J. LINDGREN;R. LINDNER;A. LIPNIACKA;I. LIPPI;B. LOERSTAD;M. LOKAJICEK;J. G. LOKEN;A. LOPEZFERNANDEZ;M. A. L.;M. LOS;D. LOUKAS;J. J. LOZANO;P. LUTZ;L. LYONS;G. MAEHLUM;J. MAILLARD;A. MALTEZOS;F. MANDL;J. MARCO;M. MARGONI;J. C. MARIN;A. MARKOU;T. MARON;S. MARTI;L. MATHIS;F. MATORRAS;C. MATTEUZZI;G. MATTHIAE;M. MAZZUCATO;M. MCCUBBIN;R. MCKAY;R. MCNULTY;G. MEOLA;C. MERONI;W. T. MEYER;M. MICHELOTTO;I. MIKULEC;W. A. MITAROFF;G. V. MITSELMAKHER;U. MJOERNMARK;T. MOA;R. MOELLER;K. MOENIG;M. R. MONGE;P. MORETTINI;H. MUELLER;W. J. MURRAY;B. MURYN;G. MYATT;F. NARAGHI;F. L. NAVARRIA;P. NEGRI;B. S. NIELSEN;B. NIJJHAR;V. NIKOLAENKO;P. E. S.;P. NISS;V. OBRAZTSOV;A. G. OLSHEVSKI;R. ORAVA;A. OSTANKOV;K. OSTERBERG;A. OURAOU;M. PAGANONI;R. PAIN;H. PALKA;T. D. PAPADOPOULOU;L. PAPE;A. PASSERI;M. PEGORARO;J. PENNANEN;V. PEREVOZCHIKOV;M. PERNICKA;A. PERROTTA;A. PETROLINI;T. E. PETTERSEN;F. PIERRE;M. PIMENTA;O. PINGOT;M. E. POL;G. POLOK;P. POROPAT;P. PRIVITERA;A. PULLIA;D. RADOJICIC;S. RAGAZZI;P. N. RATOFF;A. L. READ;N. G. REDAELLI;M. REGLER;D. REID;P. B. RENTON;L. K. RESVANIS;F. RICHARD;M. RICHARDSON;J. RIDKY;G. RINAUDO;I. RODITI;A. ROMERO;I. RONCAGLIOLO;P. RONCHESE;C. RONNQVIST;E. I. ROSENBERG;S. ROSSI;U. ROSSI;E. ROSSO;P. ROUDEAU;T. ROVELLI;W. RUCKSTUHL;V. RUHLMANN;A. RUIZ;K. RYBICKI;H. SAARIKKO;Y. SACQUIN;G. SAJOT;J. SALT;J. SANCHEZ;M. SANNINO;S. SCHAEL;H. SCHNEIDER;M. A. E.;G. SCIOLLA;F. SCURI;A. M. SEGAR;R. SEKULIN;M. SESSA;G. SETTE;R. SEUFERT;R. C. SHELLARD;I. SICCAMA;P. SIEGRIST;S. SIMONETTI;F. SIMONETTO;A. N. SISAKIAN;T. B. SKAALI;G. SKJEVLING;G. SMADJA;N. SMIRNOV;G. R. SMITH;R. SOSNOWSKI;T. S. SPASSOFF;E. SPIRITI;S. SQUARCIA;H. STAECK;C. STANESCU;S. STAPNES;G. STAVROPOULOS;F. STICHELBAUT;A. STOCCHI;J. STRAUSS;J. STRAVER;R. STRUB;M. SZCZEKOWSKI;M. SZEPTYCKA;P. SZYMANSKI;T. TABARELLI;S. TAVERNIER;O. TCHIKILEV;G. E. THEODOSIOU;A. TILQUIN;J. TIMMERMANS;V. G. TIMOFEEV;L. G. TKATCHEV;T. TODOROV;D. Z. TOET;O. TOKER;A. TOMARADZE;E. TORASSA;L. TORTORA;M. T. TRAINOR;D. TREILLE;U. TREVISAN;W. TRISCHUK;G. TRISTRAM;C. TRONCON;A. TSIROU;E. N. TSYGANOV;M. TURALA;M. L. TURLUER;T. TUUVA;I. A. TYAPKIN;M. TYNDEL;S. TZAMARIAS;S. UEBERSCHAER;O. ULLALAND;V. UVAROV;G. VALENTI;E. VALLAZZA;J. A. V.;C. VANDERVELDE;G. W. VANAPELDOORN;P. VANDAM;W. K. VANDONINCK;J. VARELA;P. VAZ;G. VEGNI;L. VENTURA;W. VENUS;F. VERBEURE;L. S. VERTOGRADOV;D. VILANOVA;L. VITALE;E. VLASOV;S. VLASSOPOULOS;A. S. VODOPYANOV;M. VOLLMER;S. VOLPONI;G. VOULGARIS;M. VOUTILAINEN;V. VRBA;H. WAHLEN;C. WALCK;F. WALDNER;M. WAYNE;A. WEHR;M. WEIERSTALL;P. WEILHAMMER;J. WERNER;A. M. WETHERELL;J. H. WICKENS;J. WIKNE;G. R. WILKINSON;W. S. C.;M. WINTER;D. WORMALD;G. WORMSER;K. WOSCHNAGG;N. YAMDAGNI;P. YEPES;A. ZAITSEV;A. ZALEWSKA;P. ZALEWSKI;D. ZAVRTANIK;E. ZEVGOLATAKOS;G. ZHANG;N. I. ZIMIN;M. ZITO;R. ZITOUN;R. ZUBERI;R. Z. FUNCHAL;G. ZUMERLE;J. ZUNIGAP., Abreu; W., Adam; T., Adye; E., Agasi; G. D., Alekseev; P., Allen; S., Almehed; S. J., Alvsvaag; U., Amaldi; E. G., Anassontzis; A., Andreazza; P., Antilogus; W. D., Apel; R. J., Apsimon; B., Asman; J. E., Augustin; A., Augustinus; P., Baillon; P., Bambade; F., Barao; R., Barate; G., Barbiellini; D. Y., Bardin; A., Baroncelli; O., Barring; J. A., Barrio; W., Bartl; M. J., Bates; M., Battaglia; M., Baubillier; K. H., Becks; C. J., Beeston; M., Begalli; P., Beilliere; Y., Belokopytov; P., Beltran; D., Benedic; M., Berggren; D., Bertrand; F., Bianchi; M. S., Bilenky; P., Billoir; J., Bjarne; D., Bloch; S., Blyth; V., Bocci; P. N., Bogolubov; T., Bolognese; M., Bonesini; W., Bonivento; P. S., L.; P., Borgeaud; G., Borisov; H., Borner; C., Bosio; B., Bostjancic; S., Bosworth; O., Botner; B., Bouquet; C., Bourdarios; T. J., V.; M., Bozzo; S., Braibant; P., Branchini; K. D., Brand; R. A., Brenner; H., Briand; C., Bricman; R. C., A.; N., Brummer; J. M., Brunet; L., Bugge; T., Buran; H., Burmeister; J. A., M.; M., Caccia; M., Calvi; A. J., C.; T., Camporesi; V., Canale; F., Cao; F., Carena; L., Carroll; C., Caso; E., Castelli; M. V., C.; A., Cattai; F. R., Cavallo; L., Cerrito; V., Chabaud; A., Chan; M., Chapkin; P., Charpentier; L., Chaussard; J., Chauveau; P., Checchia; G. A., Chelkov; L., Chevalier; P., Chliapnikov; V., Chorowicz; J. T., M.; R., Cirio; M. P., Clara; P., Collins; J. L., Contreras; R., Contri; E., Cortina; G., Cosme; F., Couchot; H. B., Crawley; D., Crennell; G., Crosetti; M., Crozon; J. C., Maestro; S., Czellar; S., Dagoret; E., Dahljensen; B., Dalmagne; M., Dam; G., Damgaard; G., Darbo; E., Daubie; A., Daum; P. D., Dauncey; M., Davenport; P., David; W., Dasilva; C., Defoix; D., Delikaris; B. A., Dellariccia; S., Delorme; P., Delpierre; N., Demaria; A., Deangelis; M., Debeer; H., Deboeck; W., Deboer; C., Declercq; M. D., M.; N., Degroot; C., Delavaissiere; B., Delotto; A., Demin; H., Dijkstra; L., Diciaccio; F., Djama; J., Dolbeau; M., Donszelmann; K., Doroba; M., Dracos; J., Drees; M., Dris; Y., Dufour; L. O., Eek; P. A., M.; R., Ehret; T., Ekelof; G., Ekspong; A. E., Peisert; J. P., Engel; D., Fassouliotis; T. A., Fearnley; M., Feindt; M. F., Alonso; A., Ferrer; T. A., Filippas; A., Firestone; H., Foeth; E., Fokitis; F., Fontanelli; K. A., J.; B., Franek; P., Frenkiel; D. C., Fries; A. G., Frodesen; R., Fruhwirth; F., Fuldaquenzer; K., Furnival; H., Furstenau; J., Fuster; G., Galeazzi; D., Gamba; C., Garcia; J., Garcia; C., Gaspar; Gasparini, Ugo; P., Gavillet; E. N., Gazis; J. P., Gerber; P., Giacomelli; R., Gokieli; V. M., Golovatyuk; J. J., G.; A., Goobar; G., Gopal; M., Gorski; V., Gracco; A., Grant; F., Grard; E., Graziani; G., Grosdidier; E., Gross; P., Grossewiesmann; B., Grossetete; J., Guy; U., Haedinger; F., Hahn; M., Hahn; S., Haider; Z., Hajduk; A., Hakansson; A., Hallgren; K., Hamacher; G. H., Demonchenault; W., Hao; F. J., Harris; T., Henkes; J. J., Hernandez; P., Herquet; H., Herr; T. L., Hessing; I., Hietanen; C. O., Higgins; E., Higon; H. J., Hilke; S. D., Hodgson; T., Hofmokl; R., Holmes; S. O., Holmgren; D., Holthuizen; P. F., Honore; J. E., Hooper; M., Houlden; J., Hrubec; P. O., Hulth; K., Hultqvist; P., Ioannou; D., Isenhower; P. S., Iversen; J. N., Jackson; P., Jalocha; G., Jarlskog; P., Jarry; B., Jeanmarie; E. K., Johansson; D., Johnson; M., Jonker; L., Jonsson; P., Juillot; G., Kalkanis; G., Kalmus; F., Kapusta; M., Karlsson; E., Karvelas; S., Katsanevas; E. C., Katsoufis; R., Keranen; J., Kesteman; B. A., Khomenko; N. N., Khovanski; B., King; N. J., Kjaer; H., Klein; W., Klempt; A., Klovning; P., Kluit; J. H., Koehne; B., Koene; P., Kokkinias; M., Kopf; K., Korcyl; A. V., Korytov; V., Kostioukhine; C., Kourkoumelis; O., Kouznetsov; P. H., Kramer; J., Krolikowski; I., Kronkvist; J., Krstic; U., Kruenermarquis; W., Krupinski; K., Kulka; K., Kurvinen; C., Lacasta; C., Lambropoulos; J. W., Lamsa; L., Lanceri; V., Lapin; J. P., Laugier; R., Lauhakangas; G., Leder; F., Ledroit; R., Leitner; Y., Lemoigne; J., Lemonne; G., Lenzen; V., Lepeltier; A., Letessierselvon; J. M., Levy; E., Lieb; D., Liko; E., Lillethun; J., Lindgren; R., Lindner; A., Lipniacka; I., Lippi; B., Loerstad; M., Lokajicek; J. G., Loken; A., Lopezfernandez; M. A., L.; M., Los; D., Loukas; J. J., Lozano; P., Lutz; L., Lyons; G., Maehlum; J., Maillard; A., Maltezos; F., Mandl; J., Marco; Margoni, Martino; J. C., Marin; A., Markou; T., Maron; S., Marti; L., Mathis; F., Matorras; C., Matteuzzi; G., Matthiae; M., Mazzucato; M., Mccubbin; R., Mckay; R., Mcnulty; G., Meola; C., Meroni; W. T., Meyer; M., Michelotto; I., Mikulec; W. A., Mitaroff; G. V., Mitselmakher; U., Mjoernmark; T., Moa; R., Moeller; K., Moenig; M. R., Monge; P., Morettini; H., Mueller; W. J., Murray; B., Muryn; G., Myatt; F., Naraghi; F. L., Navarria; P., Negri; B. S., Nielsen; B., Nijjhar; V., Nikolaenko; P. E., S.; P., Niss; V., Obraztsov; A. G., Olshevski; R., Orava; A., Ostankov; K., Osterberg; A., Ouraou; M., Paganoni; R., Pain; H., Palka; T. D., Papadopoulou; L., Pape; A., Passeri; M., Pegoraro; J., Pennanen; V., Perevozchikov; M., Pernicka; A., Perrotta; A., Petrolini; T. E., Pettersen; F., Pierre; M., Pimenta; O., Pingot; M. E., Pol; G., Polok; P., Poropat; P., Privitera; A., Pullia; D., Radojicic; S., Ragazzi; P. N., Ratoff; A. L., Read; N. G., Redaelli; M., Regler; D., Reid; P. B., Renton; L. K., Resvanis; F., Richard; M., Richardson; J., Ridky; G., Rinaudo; I., Roditi; A., Romero; I., Roncagliolo; Ronchese, Paolo; C., Ronnqvist; E. I., Rosenberg; S., Rossi; U., Rossi; E., Rosso; P., Roudeau; T., Rovelli; W., Ruckstuhl; V., Ruhlmann; A., Ruiz; K., Rybicki; H., Saarikko; Y., Sacquin; G., Sajot; J., Salt; J., Sanchez; M., Sannino; S., Schael; H., Schneider; M. A., E.; G., Sciolla; F., Scuri; A. M., Segar; R., Sekulin; M., Sessa; G., Sette; R., Seufert; R. C., Shellard; I., Siccama; P., Siegrist; S., Simonetti; Simonetto, Franco; A. N., Sisakian; T. B., Skaali; G., Skjevling; G., Smadja; N., Smirnov; G. R., Smith; R., Sosnowski; T. S., Spassoff; E., Spiriti; S., Squarcia; H., Staeck; C., Stanescu; S., Stapnes; G., Stavropoulos; F., Stichelbaut; A., Stocchi; J., Strauss; J., Straver; R., Strub; M., Szczekowski; M., Szeptycka; P., Szymanski; T., Tabarelli; S., Tavernier; O., Tchikilev; G. E., Theodosiou; A., Tilquin; J., Timmermans; V. G., Timofeev; L. G., Tkatchev; T., Todorov; D. Z., Toet; O., Toker; A., Tomaradze; E., Torassa; L., Tortora; M. T., Trainor; D., Treille; U., Trevisan; W., Trischuk; G., Tristram; C., Troncon; A., Tsirou; E. N., Tsyganov; M., Turala; M. L., Turluer; T., Tuuva; I. A., Tyapkin; M., Tyndel; S., Tzamarias; S., Ueberschaer; O., Ullaland; V., Uvarov; G., Valenti; E., Vallazza; J. A., V.; C., Vandervelde; G. W., Vanapeldoorn; P., Vandam; W. K., Vandoninck; J., Varela; P., Vaz; G., Vegni; L., Ventura; W., Venus; F., Verbeure; L. S., Vertogradov; D., Vilanova; L., Vitale; E., Vlasov; S., Vlassopoulos; A. S., Vodopyanov; M., Vollmer; S., Volponi; G., Voulgaris; M., Voutilainen; V., Vrba; H., Wahlen; C., Walck; F., Waldner; M., Wayne; A., Wehr; M., Weierstall; P., Weilhammer; J., Werner; A. M., Wetherell; J. H., Wickens; J., Wikne; G. R., Wilkinson; W. S., C.; M., Winter; D., Wormald; G., Wormser; K., Woschnagg; N., Yamdagni; P., Yepes; A., Zaitsev; A., Zalewska; P., Zalewski; D., Zavrtanik; E., Zevgolatakos; G., Zhang; N. I., Zimin; M., Zito; R., Zitoun; R., Zuberi; R. Z., Funchal; Zumerle, Gianni; J., Zunig

Charged particle multiplicity distributions for fixed number of jets in Z0 hadronic decays

The multiplicity distributions of charged particles in full phase space and in restricted rapidity intervals for events with a fixed number of jets measured by the DELPHI detector are presented. The data are well reproduced by the Lund Parton Shower model and can also be well described by fitted negative binomial distributions. The properties of these distributions in terms of the clan model are discussed. In symmetric 3-jet events the candidate gluon jet is found not to be significantly different in average multiplicity than the mean of the other two jets, thus supporting previous results of the HRS and OPAL experiments. Similar results hold for events generated according to the LUND PS and to the HERWIG models, when the jets are defined by the JADE jet finding algorithm. The method seems to be insensitive for measuring the color charge ratio between gluons and quarks. © 1992 Springer-Verlag.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Production characteristics of K-0 and light meson resonances in hadronic decays of the Z(0)

An analysis of inclusive production of KO and the meson resonances K*(+/-)(892), rho(0)(770), f(0)(975) and f(2)(1270) in hadronic decays of the Z(0) is presented, based on about 973,000 multihadronic events collected by the DELPHI detector at LEP during 1991 and 1992. Overall multiplicities have been determined as 1.962 +/- 0.060 K-0 mesons, 0.712 +/- 0.067 K*(+/-)(892) and 1.21 +/- 0.15 rho(0)(770) per hadronic Z(0) decay. The average multiplicities of f(0)(975) for scaled momentum, x(p) = p/p(beam), in the range 0.05 less than or equal to x(p) less than or equal to 0.6 and of f(2)(1270) for 0.05 less than or equal to x(p) less than or equal to 1.0 are 0.098 +/- 0.016 and 0.170 +/- 0.043 respectively. The f(0)(975) and rho(0)(770) x(p)-spectra have p similar shapes. The f(2)(1270)/rho(0)(770) ratio increases with x(p). The average multiplicities and the differential cross sections are compared with the JETSET Parton Shower model. The model with default parameters fails to reproduce the experimental K-0 momentum spectrum at low momentum, describes the K*(+/-)(892) and rho(0)(770) x(p)-spectrum shapes, but significantly overestimates their production rates

FIRST EVIDENCE OF HARD SCATTERING PROCESSES IN SINGLE TAGGED GAMMA-GAMMA-COLLISIONS

For the first time, multihadronic production from single tagged γγ collisions has been studied, where one of the scattered leptons was tagged at very low virtual photon absolute mass squared (〈Q2〉 = 0.06 (GeV/c2)2). Data collected during 1991 and 1992 in the DELPHI experiment at LEP are shown to agree well with predictions which included the non-perturbative vector meson dominance model in which the interacting photons are assumed to have converted into a vector meson (ρ{variant}, ω or π), a quark-parton model which describes direct photon interactions and a QCD-based model which considers the photon to have quark and gluon structure functions. Five different parametrizations of these structure functions were used and the predictions compared with the data. This study confirms recent results from no-tag experiments in requiring a QCD-based component to successfully describe the data, indicating that the photon has a significant partonic content. © 1995

Measurement of the forward-backward asymmetry of e(+)e(-)-]Z-]B(B)over-bar using prompt leptons and a lifetime tag

The forward-backward asymmetry of the process e(+)e(-) --> Z --> b ($) over bar b has been measured using events collected ee by the DELPHI experiment during the 1991 and 1992 LEP runs. This data sample corresponded to 884 000 hadronic Z decays at a centre-of-mass energy root s similar to M(Z). The tagging of b-quark events was performed using two approaches; the first was based on the semileptonic decay channels b --> X + mu and b --> X + e, the second used a lifetime tag with jet-charge reconstruction. The results of these two methods were combined to give A(FB)(b ($) over bar b) = 0.107 +/- 0.011(stat. + syst. + mixing). With the semileptonic sample, the forward-backward asymmetry of the process e(+)e(-) --> Z --> c ($) over bar c was also measured to be A(FB)(c ($) over bar c) = 0.083 +/- 0.022(stat.) +/- 0.016(syst.). The effective value of the Weinberg mixing angle derived from these measurements was sin(2) theta(eff)(lep) = 0.2294 +/- 0.0021