B. Alvarez Gonzalezv

Publications (3)0 Total impact

• Article: Measurement of the Bs Lifetime in Fully and Partially Reconstructed Bs -> Ds- (phi pi-)X Decays in pbar-p Collisions at sqrt(s) = 1.96 TeV

  T. Aaltonen, B. Alvarez Gonzalezv, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, J A Appel, A Apresyan, [......], K Yorita, T. Yoshidaj, G. B. Yu, I Yu, S S Yu, J. C. Yun, A Zanetti, Y Zeng, S. Zucchelliz, M Corbo
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  ABSTRACT: We present a measurement of the Bs lifetime in fully and partially reconstructed Bs -> Ds(phi pi)X decays in 1.3 fb-1 of pbar-p collisions at sqrt(s) = 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron. We measure tau(Bs) = 1.518 +/- 0.041 (stat.) +/- 0.027 (syst.) ps. The ratio of this result and the world average B0 lifetime yields tau(Bs)/tau(B0) = 0.99 +/-0.03, which is in agreement with recent theoretical predictions.
• Article: Search for Production of Heavy Particles Decaying to Top Quarks and Invisible Particles in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

  T. Aaltonen, B. Alvarez Gonzalezv, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, J A Appel, A Apresyan, [......], J Yoh, K Yorita, T. Yoshidaj, G. B. Yu, I Yu, S S Yu, J. C. Yun, A Zanetti, Y Zeng, S. Zucchelliz
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  ABSTRACT: 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$/c^2$.
• Article: Search for the Higgs boson in the all-hadronic final state using the CDF II detector

  T. Aaltonen, B. Alvarez Gonzalezv, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, J A Appel, A Apresyan, [......], J Yoh, K Yorita, T. Yoshidaj, G. B. Yu, I Yu, S S Yu, J. C. Yun, A Zanetti, Y Zeng, S. Zucchelliz
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  ABSTRACT: We report on a search for the production of the Higgs boson decaying to two bottom quarks accompanied by two additional quarks. The data sample used corresponds to an integrated luminosity of approximately 4 fb${-1}$ of $p\bar{p}$ collisions at \surd s = 1.96 TeV recorded by the CDF II experiment. This search includes twice the data of the previous published result, uses new analysis techniques to distinguish jets originating from light flavor quarks and those from gluon radiation, and adds sensitivity to a Higgs boson produced by vector boson fusion. We find no evidence of the Higgs boson and place limits on the Higgs boson production cross-section for Higgs boson masses between 100 GeV/c$^{2}$ and 150 GeV/c$^{2}$ at 95% confidence level. For a Higgs boson mass of 120 GeV/c$^{2}$ the observed (expected) limit is 10.5 (20.0) times the predicted Standard Model cross-section.