We present a measurement of the ratio of the tt-bar production cross section via gluon-gluon fusion to the total tt-bar production cross section in p anti-p collisions at s**(1/2) =1.96 TeV at the Tevatron. Using a data sample with an integrated luminosity of 955 pb-1 recorded by the CDF II detector at Fermilab, we select events based on the tt-bar decay to lepton+jets. Using an artificial neural network technique we discriminate between tt-bar events produced via qq-bar annihilation and gg fusion, and find G_f =sigma(gg --> tt-bar)/sigma(p anti-p --> tt-bar) < 0.33 at the 68% confidence level. This result is combined with a previous measurement to obtain the most stringent measurement of this quantity by CDF to date, G_f 0.070.15_-0.07.
Measurement of the Fraction of tt-bar Production via Gluon-Gluon Fusion in p anti-p Collisions at s**(1/2) =1.96 TeV / A. Castro; M. Deninno; P. Mazzanti; N. Moggi; F. Rimondi; F. Semeria; S. Zucchelli. - In: PHYSICAL REVIEW D, PARTICLES, FIELDS, GRAVITATION, AND COSMOLOGY. - ISSN 1550-7998. - STAMPA. - 79:(2009), pp. 031101-1-031101-8. [10.1103/PhysRevD.79.031101]
Measurement of the Fraction of tt-bar Production via Gluon-Gluon Fusion in p anti-p Collisions at s**(1/2) =1.96 TeV
CASTRO, ANDREA;DENINNO, MARIA MADDALENA;MOGGI, NICCOLO';RIMONDI, FRANCO;ZUCCHELLI, STEFANO
2009
Abstract
We present a measurement of the ratio of the tt-bar production cross section via gluon-gluon fusion to the total tt-bar production cross section in p anti-p collisions at s**(1/2) =1.96 TeV at the Tevatron. Using a data sample with an integrated luminosity of 955 pb-1 recorded by the CDF II detector at Fermilab, we select events based on the tt-bar decay to lepton+jets. Using an artificial neural network technique we discriminate between tt-bar events produced via qq-bar annihilation and gg fusion, and find G_f =sigma(gg --> tt-bar)/sigma(p anti-p --> tt-bar) < 0.33 at the 68% confidence level. This result is combined with a previous measurement to obtain the most stringent measurement of this quantity by CDF to date, G_f 0.070.15_-0.07.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.