Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter

This is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2010 IOPEnsuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered

Search for the W-exchange decays B0 --> Ds(*)- Ds(*)+

We report a search for the decays $B^{0} \to D_{s}^{-} D_{s}^{+}$, $B^{0} \to D_{s}^{*-} D_{s}^{+}$, $B^{0} \to D_{s}^{*-} D_{s}^{*+}$ in a sample of 232 million $\Upsilon(4S)$ decays to \BBb ~pairs collected with the \babar detector at the PEP-II asymmetric-energy $e^+ e^-$ storage ring. We find no significant signal and set upper bounds for the branching fractions: ${\cal B}(B^{0} \to D_{s}^{-} D_{s}^{+}) < 1.0 \times 10^{-4}, {\cal B}(B^{0} \to D_{s}^{*-} D_{s}^{+}) < 1.3 \times 10^{-4}$ and ${\cal B}(B^{0} \to D_{s}^{*-} D_{s}^{*+}) < 2.4 \times 10^{-4}$ at 90% confidence level.Comment: 8 pages, 2 figures, submitted to PRD-R

Measurement of the B+ --> p pbar K+ Branching Fraction and Study of the Decay Dynamics

With a sample of 232x10^6 Upsilon(4S) --> BBbar events collected with the BaBar detector, we study the decay B+ --> p pbar K+ excluding charmonium decays to ppbar. We measure a branching fraction Br(B+ --> p pbar K+)=(6.7+/-0.5+/-0.4)x10^{-6}. An enhancement at low ppbar mass is observed and the Dalitz plot asymmetry suggests dominance of the penguin amplitude in this B decay. We search for a pentaquark candidate Theta*++ decaying into pK+ in the mass range 1.43 to 2.00 GeV/c2 and set limits on Br(B+ --> Theta*++pbar)xBr(Theta*++ --> pK+) at the 10^{-7} level.Comment: 8 pages, 7 postscript figures, submitted to Phys. Rev. D (Rapid Communications

Measurement of the branching fraction ratios and CP asymmetries in B-→ D0 CP K-decays

We present a preliminary study of $B^- \to D^0_{CP} \pi^-$ and $B^- \to D^0_{CP} K^-$ decays, with the $D^0_{CP}$ reconstructed in the CP-odd eigenstates $K_s \pi^0$, $K_s \omega$, in the CP-even eigenstates $K^+ K^-$, $\pi^+ \pi^-$, and in the (non-CP) flavor eigenstate $K^\mp \pi^\pm$. Using a sample of about 382 million Y(4S) decays into BBbar pairs, collected with the BABAR detector operating at the PEP-II asymmetric-energy B Factory at SLAC, we measure the ratios of the branching fractions R_CP+- and the direct CP asymmetries A_CP+-. The results are: R_CP- = 0.81 \pm 0.10 (stat) \pm 0.05 (syst) R_CP+ = 1.07 \pm 0.10 (stat) \pm 0.04 (syst) A_CP- = -0.19 \pm 0.12 (stat) \pm 0.02 (syst) A_CP+ = 0.35 \pm 0.09 (stat) \pm 0.05 (syst

Search for the decay B0→a1±ρ

DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF and DFG (Germany), INFN (Italy), FOM (The Netherlands), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from CONACyT (Mexico), Marie Curie EIF (European Union), the A. P. Sloan Foundation, the Research Corporation, and the Alexander von Humboldt Foundation

Measurement of branching fractions and charge asymmetries in B decays to an eta meson and a K-* meson

We present measurements of branching fractions and charge asymmetries for the decays B ->eta K-*, where K-* indicates a spin 0, 1, or 2 K pi system. The data sample corresponds to 344x10(6) B (B) over bar pairs collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at SLAC. We measure the branching fractions (in units of 10(-6)): B(B-0 ->eta K-*0(892))=16.5 +/- 1.1 +/- 0.8, B(B+->eta K*+(892))=18.9 +/- 1.8 +/- 1.3, B(B-0 ->eta(K pi)(0)(*0))=11.0 +/- 1.6 +/- 1.5, B(B+->eta(K pi)(0)(*+))=18.2 +/- 2.6 +/- 2.6, B(B-0 ->eta K-2(*0)(1430))=9.6 +/- 1.8 +/- 1.1, and B(B+->eta K-2(*+)(1430))=9.1 +/- 2.7 +/- 1.4. We also determine the charge asymmetries for all decay modes

Depuzzling B→KπB \to K\pi: constraints on the Unitarity Triangle from BB, Bs→ππB_s \to \pi\pi, KπK\pi, KKKK decays in the SU(3)SU(3) limit

Talk given at "Rencontres de Moriond 2006, Electroweak" by Julie Malclès based on work in collaboration with Jérôme Charles and José OcarizConstraining CKM parameters from charmless hadronic B decays requires methods for addressing the hadronic uncertainties. A complete technique is presented, using relations between amplitudes in the B, Bs -> pipi, Kpi, KK system obtained in the exact SU(3) symmetry limit, without having to neglect annihilation/exchange topologies. Naive SU(3)-breaking effects in the decay amplitudes are taken into account, through the inclusion of pi and K decay constants in the normalisations and conservative theoretical errors. Already with the limited set of observables currently available, significant constraints on the CKM parameters are obtained. Also, subsets of observables are shown to bring non trivial constraints on the CKM angles alpha and beta, in agreement with analytical solutions that we derive. Finally, the future physics potential of this method is estimated, in light of the increased precision of measurements from the current B-factories, and the inclusion of several new observables from Bs decays expected to be provided by the LHC experiments