Search for anomalous couplings in the $Wtb$ vertex from the measurement of double differential angular decay rates of single top quarks produced in the $t$-channel with the ATLAS detector
2019
Online
academicJournal
Zugriff:
The electroweak production and subsequent decay of single top quarks is determined by the properties of the $Wtb$ vertex. This vertex can be described by the complex parameters of an effective Lagrangian. An analysis of angular distributions of the decay products of single top quarks produced in the $t$-channel constrains these parameters simultaneously. The analysis described in this paper uses 4.6 fb$^{-1}$ of proton-proton collision data at $\sqrt{s}$ = 7 TeV collected with the ATLAS detector at the LHC.Two parameters are measured simultaneously in this analysis. The fraction $f_1$ of decays containing transversely polarised $W$ bosons is measured to be $0.37 \pm 0.07$ (stat.$\oplus$syst.). The phase $\delta_{-}$ between amplitudes for transversely and longitudinally polarised $W$ bosons recoiling against left-handed $b$-quarks is measured to be $-0.14\pi \pm 0.036\pi$ (stat.$\oplus$syst.).The correlation in the measurement of these parameters is $0.15$. These values result in two-dimensional limits at the 95% confidence level on the ratio of the complex coupling parameters $g_\mathrm{R}$ and $V_\mathrm{L}$, yielding Re [$g_\mathrm{R}/V_\mathrm{L}$] $\in [-0.36,0.10]$ and Im [$g_\mathrm{R}/V_\mathrm{L}$] $\in [-0.17,0.23]$ with a correlation of 0.11. The results are in good agreement with the predictions of the Standard Model. ; Peer Reviewed
Titel: |
Search for anomalous couplings in the $Wtb$ vertex from the measurement of double differential angular decay rates of single top quarks produced in the $t$-channel with the ATLAS detector
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Autor/in / Beteiligte Person: | ATLAS collaboration (2866 authors) ; Aguilar-Saavedra, Juan Antonio ; Amor Dos Santos, Susana Patricia ; Anjos, Nuno ; Araque, Juan Pedro ; Cantrill, Robert ; Carvalho, João ; Castro, Nuno Filipe ; Conde Muiño, Patricia ; Da Cunha Sargedas De Sousa, Mario Jose ; Fiolhais, Miguel ; Galhardo, Bruno ; Gomes, Agostinho ; Gonçalo, Ricardo ; Jorge, Pedro ; Lopes, Lourenco ; Machado Miguens, Joana ; Maio, Amélia ; Maneira, José ; Onofre, António ; Palma, Alberto ; Pedro, Rute ; Pina, João Antonio ; Santos, Helena ; Saraiva, João ; Silva, José ; Tavares Delgado, Ademar ; Veloso, Filipe ; Wolters, Helmut |
Link: | |
Veröffentlichung: | 2019 |
Medientyp: | academicJournal |
DOI: | 10.1007/JHEP04(2016)023 |
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