150 articles – 1931 Notices  [english version]
 HAL : in2p3-00578789, version 1
 arXiv : 1103.2482
 Code Bibliographique ADS : 2011PhRvL.106s1801A
 Physical Review Letters 106 (2011) 191801
 Search for Production of Heavy Particles Decaying to Top Quarks and Invisible Particles in pp̅ Collisions at √s=1.96 TeV
 CDF Collaboration(s)
 (05/2011)
 We present a search for a new particle $T'$ decaying to top quark via $T^{\prime} \rightarrow t + X$, where $X$ is an invisible particle. In a data sample with 4.8 fb$^{-1}$ of integrated luminosity collected by the CDF II detector at Fermilab in $p\bar{p}$ collisions with $\sqrt{s}=1.96$ TeV, we search for pair production of $T'$ in the lepton+jets channel, $p\bar{p} \rightarrow t\bar{t} +X+X \rightarrow \ell\nu b q q' b + X +X$. We interpret our results primarily in terms of a model where $T'$ are exotic fourth generation quarks and $X$ are dark matter particles. Current direct and indirect bounds on such exotic quarks restrict their masses to be between 300 and 600 GeV$/c^2$, the dark matter particle mass being anywhere below $m_{T^{\prime}}$. The data are consistent with standard model expectations, and we set 95% confidence level limits on the generic production of $T'\bar{T'} \rightarrow t\bar{t}+X+X$. We apply these limits to the dark matter model and exclude the fourth generation exotic quarks $T'$ at 95% confidence level up to $m_{T'}=360$ GeV$/c^{2}$ for $m_X\le 100$ GeV$/c^2$.
 équipe(s) de recherche : APC - AHE
 Thème(s) : Physique/Physique des Hautes Energies - ExpériencePlanète et Univers/Astrophysique/Phénomènes cosmiques de haute energiePhysique/Astrophysique/Phénomènes cosmiques de haute energie
 Lien vers le texte intégral : http://fr.arXiv.org/abs/1103.2482
 in2p3-00578789, version 1 http://hal.in2p3.fr/in2p3-00578789 oai:hal.in2p3.fr:in2p3-00578789 Contributeur : Swarna Bassava <> Soumis le : Mardi 22 Mars 2011, 11:54:16 Dernière modification le : Dimanche 7 Octobre 2012, 00:33:23