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We report final measurements of direct $mathit{CP}$--violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using the complete $sqrt{s}=1.96$ TeV p roton-antiproton collisions data set, corresponding to 9.3 fb$^{-1}$ of integrated luminosity, we measure $mathcal{A}(Lambda^0_b rightarrow ppi^{-}) = +0.06 pm 0.07mathrm{(stat)} pm 0.03mathrm{(syst)}$ and $mathcal{A}(Lambda^0_b rightarrow pK^{-}) = -0.10 pm 0.08mathrm{(stat)} pm 0.04mathrm{(syst)}$, compatible with no asymmetry. In addition we measure the $mathit{CP}$--violating asymmetries in $B^0_s rightarrow K^{-}pi^{+}$ and $B^0 rightarrow K^{+}pi^{-}$ decays to be $mathcal{A}(B^0_s rightarrow K^{-}pi^{+}) = +0.22 pm 0.07mathrm{stat)} pm 0.02mathrm{(syst)}$ and $mathcal{A}(B^0 rightarrow K^{+}pi^{-}) = -0.083pm 0.013 mathrm{(stat)} pm 0.004mathrm{(syst)}$, respectively, which are significantly different from zero and consistent with current world averages.
I report some recent results on direct CP violation measurements in hadronic decays collected by the upgraded Collider Detector (CDF II) at the Fermilab Tevatron: CP-violating asymmetries in the two-body non-leptonic charmless decays of $b$-hadrons, the first reconstruction in hadron collisions of the suppressed decays $B^- to D(to K^+pi^-)K^-$ and $B^- to D(to K^+pi^-)pi^-$, and the measurement of TP asymmetries in the $B^{0}_{s} to phi phi$ decays.
Charm physics has played all along a central role in particle physics, however the level of attention on it has tremendously increased in the last years because of the observation of fast $D^0-bar{D}^0$ flavour oscillations and because of very recent observed hints of CP violation. While in the past these would have been unambiguously interpreted as signs of New Physics, the revisitation of theoretical expectations, prompted by the latest experimental measurements, makes the picture not clear. This brief review covers the current status of CP-violating measurements in the $D^0-bar{D}^0$ system, both on the experimental and theoretical side.
The CDF experiment at the Tevatron $pbar{p}$ collider established that extensive and detailed exploration of the $b$--quark dynamics is possible in hadron collisions, with results competitive and supplementary to those from $e^+e^-$ colliders. This p rovides a rich, and highly rewarding program that has currently reached full maturity. In the following I report some recent results on hadronic decays: the evidence for the charmless annihilation decay mode $B^0_s to pi^+pi^-$, and the first reconstruction in hadron collisions of the suppressed decays $B^- to D(to K^+pi^-)K^-$ and $B^- to D(to K^+pi^-)pi^-$.
99 - CDF Collaboration 2011
We search for annihilation decay modes of neutral $b$ mesons into pairs of charmless charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 6 fb$^{-1}$ of integrated luminosity, we obtain th e first evidence for the $B^0_s to pi^+pi^-$ decay, with a significance of $3.7sigma$, and a measured branching ratio $mathcal{B}(B^0_s to pi^+pi^-)= (0.57 pm 0.15 (stat) pm 0.10 (syst))times 10^{-6}$. A search for the $B^0 to K^+K^-$ mode in the same sample yields a significance of $2.0sigma$, and a central value estimate $mathcal{B}(B^0 to K^+K^-)= (0.23 pm 0.10 (stat) pm 0.10 (syst))times 10^{-6}$.
The CDF and DO experiments at the Tevatron $pbar{p}$ collider established that extensive and detailed exploration of the $b$--quark dynamics is possible in hadron collisions, with results competitive and supplementary to those from $e^+e^-$ colliders . This provides a rich, and highly rewarding program that is currently reaching full maturity. I report a few recent world-leading results on rare decays, CP-violation in $B^0_s$ mixing, $bto s$ penguin decays, and charm physics.
We report a measurement of the CP violating asymmetry in $D^0topi^+pi^-$ decays using approximately 215,000 decays reconstructed in about $5.94$ fb$^{-1}$ of CDF data. We use the strong $D^{star +}to D^0pi^+$ decay ($D^{star}$ tag) to identify the flavor of the charmed meson at production time and exploit CP-conserving strong $cbar{c}$ pair-production in $pbar{p}$ collisions. Higher statistic samples of Cabibbo-favored $D^0to K^-pi^+$ decays with and without $D^{star}$ tag are used to highly suppress systematic uncertainties due to detector effects. The result, $Acp(D^0 to pi^{+}pi^{-}) = bigl[0.22pm0.24statpm0.11systbigr]%$, is the worlds most precise measurement to date and it is fully consistent with no CP violation.
102 - Michael J. Morello 2010
We search for new charmless decays of neutral $b$--hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb$^{-1}$ of integrated luminosity, we report the first observ ation of the BsKpi decay, with a significance of $8.2sigma$, and measure $BR(BsKpi) = (5.0 pm 0.7stat pm 0.8syst)times 10^{-6}$. We also report the first observation of charmless $b$--baryon decays in the channels Lbppi and LbpK with significances of $6.0sigma$ and $11.5sigma$ respectively, and we measure $BR(Lbppi) = (3.5 pm 0.6stat pm 0.9syst)times 10^{-6}$ and $BR(LbpK) = (5.6 pm 0.8stat pm 1.5syst)times 10^{-6}$. No evidence is found for the decays BdKK and Bspipi, and we set an improved upper limit $BR(Bspipi) < 1.2times 10^{-6}$ at the 90% confidence level. All quoted branching fractions are measured using $BR(BdKpi)$ as a reference.
Processes involving flavor changing neutral currents (FCNC) provide excellent signatures with which to search for evidence of new physics. They have very small branching fractions in the Standard Model since they are highly suppressed by Glashow-Ilio poulos-Maiani (GIM) mechanism. They occur only through higher order diagrams, and new particles contributions can provide a significant enhancements, which would be an uniquevocal signs of physics beyond the Standard Model. In this paper we present the most recent measurements on FCNC processes performed by CDF and D0 Collaborations, while last section is devote to the charm physics at CDF.
The Fermilab Tevatron offers unique opportunities to perform measurements of the heavier b-hadrons that are not accessible at the Y(4S) resonance. In this summary, we describe most important heavy flavor results from DO and CDF collaborations and we discuss prospects for future measurements, that could reveal New Physics before the start-up of the Large Hadron Collider (LHC).
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