The cross-section for e + e − → hadrons in the vicinity of the Z boson peak has been measured with the ALEPH detector at the CERN Large Electron Positron collider, LEP. Measurements of the Z mass, M z = (91.174±0.070) GeV, the Z width Γ z =(2.68±0.15) GeV, and of the peak hadronic cross-section, σ had peak =(29.3±1.2) nb, are presented. With the constraints of the standard electroweak model, the number of light neutrino species is found to be N v =3.27±0.30. this results rules out of the possibility of a fourth type of light neutrino at 98% CL.
Determination of the Number of Light Neutrino Species
DECAMP D;DESCHIZEAUX B;LEES JP;MINARD MN;CRESPO JM;DELFINO M;FERNANDEZ E;MARTINEZ M;MIQUEL R;MIR ML;ORTEU S;PACHECO A;PERLAS JA;TUBAU E;CATANESI MG;DEPALMA M;FARILLA A;IASELLI G;MAGGI G;MASTROGIACOMO A;NATALI S;NUZZO S;RANIERI A;RASO G;ROMANO F;RUGGIERI F;SELVAGGI G;SILVESTRIS L;TEMPESTA P;ZITO G;CHEN Y;HUANG D;LIN J;RUAN T;WANG T;WU W;XIE Y;XU D;XU R;ZHANG J;ZHAO W;ALBRECHT H;BIRD F;BLUCHER E;CHARITY T;DREVERMANN H;GARRIDO L;GRAB C;HAGELBERG R;HAYWOOD S;JOST B;KASEMANN M;KELLNER G;KNOBLOCH J;LACOURT A;LEHRAUS I;LOHSE T;LUKE D;MARCHIORO A;MATO P;MAY J;MERTENS V;MINTEN A;MIOTTO A;PALAZZI P;PEPEALTARELLI M;RANJARD F;RICHSTEIN J;ROTH A;ROTHBERG J;ROTSCHEIDT H;VONRUDEN W;SCHLATTER D;STDENIS R;TAKASHIMA M;TALBY M;TAUREG H;TEJESSY W;WACHSMUTH H;WHEELER S;WIEDENMANN W;WITZELING W;WOTSCHACK J;AJALTOUNI Z;BARDADINOTWINOWSKA M;FALVARD A;GAY P;HENRARD P;JOUSSET J;MICHEL B;MONTRET JC;PALLIN D;PERRET P;PRAT J;PRORIOL J;PRULHIERE F;BERTELSEN H;HANSEN F;HANSEN JR;HANSEN JD;HANSEN PH;LINDAHL A;MADSEN B;MOLLERUD R;NILSSON BS;PETERSEN G;SIMOPOULOU E;VAYAKI A;BADIER J;BERNARD D;BLONDEL A;BONNEAUD G;BOUROTTE J;BRAEMS F;BRIENT JC;CIOCCI MA;FOUQUE G;GUIRLET R;MINE P;ROUGE A;RUMPF M;VIDEAU H;VIDEAU I;ZWIERSKI D;CANDLIN DJ;CONTI A;PARRINI G;CORDEN M;GEORGIOPOULOS C;GOLDMAN JH;IKEDA M;LEVINTHAL D;LANNUTTI J;MERMIKIDES M;SAWYER L;ANTONELLI A;BALDINI R;BENCIVENNI G;BOLOGNA G;BOSSI F;CAMPANA P;CAPON G;CHIARELLA V;DENINNO G;DETTORREPIAZZOLI B;FELICI G;LAURELLI P;MANNOCCHI G;MURTAS F;MURTAS GP;NICOLETTI G;PICCHI P;ZOGRAFOU P;ALTOON B;BOYLE O;FLAVELL AJ;HALLEY AW;TENHAVE I;HEARNS JA;HUGHES IS;LYNCH JG;MARTIN DJ;ONEILL R;RAINE C;SCARR JM;SMITH K;THOMPSON AS;BRANDL B;BRAUN O;GEIGES R;GEWENIGER C;HANKE P;HEPP V;KLUGE EE;MAUMARY Y;PANTER M;PUTZER A;RENSCH B;STAHL A;TITTEL K;WUNSCH M;BARBER GJ;BELK AT;BEUSELINCK R;BINNIE DM;CAMERON W;CATTANEO M;DORNAN PJ;DUGEAY S;FORTY RW;GENTRY DN;HASSARD JF;MILLER DG;PRICE DR;SEDGBEER JK;TOMALIN IR;TAYLOR G;GIRTLER P;KUHN D;RUDOLPH G;BRODBECK TJ;BOWDERY C;FINCH AJ;FOSTER F;HUGHES G;KEEMER NR;NUTTALL M;ROWLINGSON BS;SLOAN T;SNOW SW;BARCZEWSKI T;BAUERDICK LAT;KLEINKNECHT K;POLLMANN D;RENK B;ROEHN S;SANDER HG;SCHMELLING M;STEEG F;ALBANESE JP;AUBERT JJ;BENCHOUK C;BONISSENT A;ETIENNE F;NACASCH R;PAYRE P;PIETRZYK B;QIAN Z;BLUM W;CATTANEO P;COMIN M;DEHNING B;COWAN G;DIETL H;FERNANDEZBOSMAN M;HAUFF D;JAHN A;LANGE E;LUTJENS G;LUTZ G;MANNER W;MOSER HG;PAN Y;RICHTER R;SCHWARZ A;SETTLES R;STIEGLER U;STIERLIN U;STIMPFL G;THOMAS J;WALTERMANN G;BOUCROT J;CALLOT O;CORDIER A;DAVIER M;DEBOUARD G;GANIS G;GRIVAZ JF;HEUSSE P;JANOT P;JOURNE V;KIM DW;LEFRANCOIS J;LLOYDOWEN D;LUTZ AM;MAROTTE P;VEILLET JJ;AMENDOLIA SR;BAGLIESI G;BATIGNANI G;BOSISIO L;BOTTIGLI U;BRADASCHIA C;FERRANTE I;FIDECARO F;FOA L;FOCARDI E;FORTI F;GIASSI A;GIORGI MA;LIGABUE, FRANCO;LUSIANI, AlbertoMembro del Collaboration Group
;MANNELLI EB;MARROCCHESI PS;MESSINEO A;PALLA F;SANGUINETTI G;SCAPELLATO S;STEINBERGER J;TENCHINI R;TONELLI G;TRIGGIANI G;CARTER JM;GREEN MG;MCKEMEY AK;MARCH PV;MEDCALF T;SAICH MR;STRONG J;THOMAS RM;WILDISH T;BOTTERILL DR;CLIFFT RW;EDGECOCK TR;EDWARDS M;FISHER SM;HILL DL;JONES TJ;MCPHERSON G;MORRISSEY M;NORTON PR;SALMON DP;TAPPERN GJ;THOMPSON JC;HARVEY J;BLOCHDEVAUX B;COLAS P;KLOPFENSTEIN C;LANCON E;LOCCI E;LOUCATOS S;MIRABITO L;MONNIER E;PEREZ P;PERRIER F;PIGNARD B;RANDER J;RENARDY JF;ROUSSARIE A;SCHULLER JP;TURLAY R;ASHMAN JG;BOOTH CN;COMBLEY F;DINSDALE M;MARTIN J;PARKER D;THOMPSON LF;BRANDT S;BURKHARDT H;GRUPEN C;MEINHARD H;NEUGEBAUER E;SCHAFER U;SEYWERD H;STUPPERICH K;GOBBO B;LIELLO F;MILOTTI E;RAGUSA F;ROLANDI, LUIGI;BELLANTONI L;BOUDREAU JF;CINABRO D;CONWAY JS;COWEN DF;FENG Z;HARTON JL;HILGART J;JARED RC;JOHNSON RP;LECLAIRE BW;PAN YB;PARKER T;PATER JR;SAADI Y;SHARMA V;WEAR JA;WEBER FV;WU SL;XUE ST;ZOBERNIG G;RI Perrier Frederic/A 5953 2011 Stahl Achim/E 8846 2011 S.t. Denis Richard/C 8997 2012 Ferrante Isidoro/F 1017 2012
1989
Abstract
The cross-section for e + e − → hadrons in the vicinity of the Z boson peak has been measured with the ALEPH detector at the CERN Large Electron Positron collider, LEP. Measurements of the Z mass, M z = (91.174±0.070) GeV, the Z width Γ z =(2.68±0.15) GeV, and of the peak hadronic cross-section, σ had peak =(29.3±1.2) nb, are presented. With the constraints of the standard electroweak model, the number of light neutrino species is found to be N v =3.27±0.30. this results rules out of the possibility of a fourth type of light neutrino at 98% CL.| File | Dimensione | Formato | |
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Determination-light-neutrino.pdf
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https://hdl.handle.net/11384/1735
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