Session B11: Charm and Bottom Quarks

First evidence of prompt J/$\psi $ production in association with a W boson and measurement of prompt J/$\psi +$W cross-section with 4.7 fb$-$1 of data at $\surd $s$=$ 7 TeV at the Large Hadron Collider

The process pp $\to $W$+$/- J/$\psi $ provides a powerful probe of the production mechanism of charmonium in hadronic collisions. Using the full 2011 ATLAS dataset corresponding to an integrated luminosity of 4.7 fb$-$1, we have observed the first evidence of the production of W$+$/- $+$ prompt J/$\psi $ events in proton-proton collisions in the W $+$ J/$\psi \to $ $\mu +$/- $\mu +\mu -$ channel, and measured the differential cross-section for this process.   

Charmonium Hybrids from QCD Sum-Rules

Over the past decade or so, over a dozen new charmonium-like resonances have been discovered. Many of these particles, collectively dubbed the XYZ resonances, do not fit neatly into conventional quarkonium assignments. Not surprisingly, this has fueled a great deal of speculation that some of the resonances may lie outside of the quark model. Hybrids, hadrons admitting explicit quark and gluon degrees of freedom, represent one such possibility. We use QCD Laplace sum-rules to predict ground state masses of charmonium hybrids and comment on potential phenomenological implications.   

Evidence of Narrow Structure in the J/$\psi \phi$ Mass Spectrum in Exclusive $B^{+} \rightarrow J/\psi \phi K^{+}$ decay at CMS

Analysis of heavy quarkonium states provides an effective method to test QCD predictions. Recent studies on these mesons show that there are states which have decay modes similar to charmonium, but are difficult to put in a charmonium system. Observation of Y(4140) at CDF detector inspired to search for the same structure at CMS detector. In this analysis we report the observation of two structures in the $J/\psi \phi$ mass spectrum of exclusive $B^{+} \rightarrow J/\psi \phi K^{+}$ decays, where $J/\psi \rightarrow \mu^{-} \mu^{+}$ and $\phi \rightarrow K^{+} K^{-}$. The analysis was conducted on pp collision data at $\sqrt s$ = 7 TeV using 5.2 $fb^{-1}$ of integrated luminosity collected with CMS detector at Large Hadron Collider. Interpretation of structures as $J/\psi \phi$ resonances with S-wave relativistic Breit-Wigner shape over phase-space non-resonant component resulted in significance of 5$\sigma$ for the first structure and evidence for the second structure. Fitted masses of structures are $M_{1} = 4148.2 \pm 2.0(stat) \pm 4.6(syst)$ MeV and $M_{2} = 4316.7 \pm 3.0(stat) \pm 7.3(syst)$ MeV.   

$B^0_s$ lifetime measurement from the decay $B^0_s \rightarrow J/\psi f_0(980)$

The $B^0_s$ meson is in general a superposition of CP-even and CP-odd states, which are expected to have different lifetimes. The decay $B^0_s \rightarrow J/\psi f_0(980)$ must be a pure CP-odd (orbital angular momentum $L=1$) state due to conservation of angular momentum. Measurement of the $B^0_s$ lifetime from this decay should therefore yield information on the CP-odd $B^0_s$ lifetime. We report on the $B^0_s \rightarrow J/\psi f_0(980)$ lifetime measurement using the full Run II dataset collected by the D0 detector at the Fermilab Tevatron collider.   

Search for the rare decay $B^0_s \to \mu^+ \mu^-$ at D0

The decay $B^0_s \to \mu^+ \mu^-$ is heavily suppressed in the standard model, but many scenarios for physics beyond the standard model predict large enhancements in this process. We report an updated search for this decay using data collected by the D0 detector at the Fermilab Tevatron collider. We use the full Run II data set, corresponding to approximately 10.5 fb$^{-1}$ of integrated luminosity in $p \bar{p}$ collisions at $\sqrt{s}$=1.96 TeV.   

Measurement of forward-backward asymmetry and other properties of B decays to K*ll

We present a study of B decays to $K^{(*)}$~and two leptons ($e$,$\mu$) in the full Belle $\Upsilon (4s)$ data set ($771 \times 10^6~B\bar{B}$~pairs). The flavor-changing neutral current process responsible for this decay, $b \rightarrow sl^{+}l^{-}$, proceeds via electro-weak penguin diagrams in the Standard Model. However, this process may be sensitive to new physics due to contributions from Beyond the Standard Model particles in these diagrams. We report the differential branching fraction, isospin asymmetry, $K^{*}$~polarization, and forward-backward asymmetry ($A_{FB}$) as a function of $q^2 = M_{ll}^{2}c^2$.   

Precision measurement of the D0 mass

We report a high precision measurement of the $D^0$ mass using $D^{*+} \rightarrow D^0 \pi^+, D^0 \rightarrow K^- K^- K^+ \pi^+$ decays in data collected by the B{\small{A}}B{\small{AR}} detector; the low Q-value of this decay gives us a strong control over the background and good resolution, in addition to minimizing systematic uncertainties. With a statistical uncertainty on the order of 50 keV and a total systematic uncertainty of approximately the same magnitude, which is dominated by the charged kaon mass uncertainty, our measurement will be more precise than the current world average, $1864.86 \pm 0.13$ MeV.