$\newcommand{\ttbar}{t \bar{t}} \newcommand{\ttbar}{t \bar{t}} \newcommand{\ppbar}{p \bar{p}} \newcommand{\met}{E\kern-0.50em\raise0.10ex\hbox{/}_{T}} \newcommand{\PWprime}{\textit{W'}} \newcommand{\PW}{\textit{W}} \newcommand{\tb}{\textit{tb}} \newcommand{\wptb}{\PWprime \rightarrow \tb} \newcommand{\wplnu}{\PWprime \rightarrow \ell\nu} \newcommand{\wptbxsbr}{\sigma_{\PWprime}\times\mathcal{B}(\wptb)} \newcommand{\mwp}{M_{\PWprime}} \newcommand{\invfb}{\text{fb}^{-1}} \newcommand{\gevcsq}{\text{GeV}/c^2} \newcommand{\gwp}{g_{\PWprime}} \newcommand{\gsm}{g_{\text{SM}}}$

Search for Resonances Decaying to a Top and a Bottom Quark in $\ppbar$ Collisions at $\sqrt{s}$ = 1.96 TeV

F. Anza, G. Bellettini, L. Bianchi, D. Bortoletto, M. Cremonesi, T. Junk, Y.K. Kim, Q. Liu, F. Margaroli

[Contact the authors]

Abstract

We present a search for a charged massive resonances decaying to $\tb$ in the full data set of proton-antiproton collisions at fixme recorded by the CDF II detector at the Tevatron, correspondind to an integrated luminosity of 9.5 $\invfb$. No significant excess above SM prediction is found. We place 95% C.L. mass-dependent upper limits on the heavy charged boson production cross section times branching ratio to $\tb$, using as benchmark model a $\wptb$ with left-right symmetric couplings. Assuming a $\PWprime$ boson with SM-like couplings and allowed (forbidden) decay to leptons, we exclude $\wptb$ for $\PWprime$ boson masses below 860 (880) $\gevcsq$. Relaxing the hypothesis on SM-like couplings, we exclude $\PWprime$ boson coupling strength values as a function of $\PWprime$ boson mass above 10% SM coupling strength for $\mwp$ = 300 $\gevcsq$. The constraints obtained with the present analysis are the most stringent for charged resonance masses below approximately 550 $\gevcsq$ decaying to a top and a bottom quark.

Documentation

CDF Public Note 11110.

Figures

A high-resolution version of each figure can be obtained by clicking on the thumbnails.


1


s-channel diagram for $\PWprime$ production and decay to $\tb$.


2


Numbers of predicted and observed two-jet zero-lepton events in the 1T, TL, and TT subsamples. The uncertainties on the predicted numbers of events are due to the theoretical-cross- section uncertainties and the uncertainties on signal and background modeling. Expected number of events for one choice of $\PWprime$ mass and $\wptbxsbr$ is also shown.


3


Numbers of predicted and observed two-jet one-lepton events in the 1T, TL, and TT subsamples.


4


Numbers of predicted and observed three-jet zero-lepton events in the 1T, TL, and TT subsamples.


5


Numbers of predicted and observed three-jet one-lepton events in the 1T, TL, and TT subsamples.


6a--f

(a) (b)
(c) (d)
(e) (f)
Predicted and observed final discriminant distributions in the no-lepton signal region, for (a) 1T two-jet, (b) 1T three-jet, (c) TL two-jet, (d) TL three-jet, (e) TT two-jet and (f) TT three-jet event subsamples.


7a--f

(a) (b)
(c) (d)
(e) (f)
Predicted and observed final discriminant distributions in the lepton signal region, for (a) 1T two-jet, (b) 1T three-jet, (c) TL two-jet, (d) TL three-jet, (e) TT two-jet and (f) TT three-jet event subsamples.


8


Observed and expected 95% C.L upper limits on $\wptbxsbr$ as a function of $\mwp$, with $\pm1\sigma$ and $\pm2\sigma$ confidence intervals and theoretical predictions for a right-handed $\PWprime$ boson with SM-like couplings in cases where the leptonic decay mode $\wplnu$ is forbidden (dashed line). The CDF limits are compared with limits from the lates $\PWprime$ searches from ATLAS, CMS and D0.


9


Observed and expected 95% C.L upper limits on the coupling strenght of a right-handed $\PWprime$ boson compared to the SM $\PW$ boson coupling $\gwp / \gsm$, as a function of $\mwp$, in cases where the leptonic decay mode $\wplnu$ is forbidden. The region above each line is excluded.


Last updated: 2015-04-29 by L. Bianchi. HTML is generated automatically from the GFM source.