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

Observation of Scaling Violations in Scaled Momentum Distributions at HERA

Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of $x$ and $Q^2$ using the ZEUS detector. The evolution of the scaled momentum, $x_p$, with $Q^2,$ in the range 10 to 1280 $GeV^2$, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of $Q^2$.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde

The factorizable amplitude in B0→π+π−B^0 \to \pi^+ \pi^-

Using the measured spectrum shape for $B \to \pi \ell \nu$, the rate for $B^+ \to \pi^+ \pi^0$, information on the Cabibbo-Kobayashi-Maskawa (CKM) matrix element $|V_{ub}|$, and theoretical inputs from factorization and lattice gauge theory, we obtain an improved estimate of the ``tree'' contribution to $B^0 \to \pi^+ \pi^-$. We find the branching ratio \b(B^0 \to \pi^+ \pi^-)|_{\rm tree} = (5.25^{+1.67}_{-0.50}) \times 10^{-6}, to be compared with the experimental value \b(B^0 \to \pi^+ \pi^-) = (4.55 \pm 0.44) \times 10^{-6}. The fit implies $|V_{ub}| = (3.62 \pm 0.34) \times 10^{-3}$. Implications for tree-penguin interference in $B^0 \to \pi^+ \pi^-$ and for other charmless $B$ decays are discussed.Comment: 11 pages, LaTeX, 3 figures, to be submitted to Phys. Rev.

Experimental Results in Heavy Flavor Physics

The interplay of experiment and theory is explored in the context of current data on b and c decay. Measurements of |Vcb| and |Vub| are extracted from existing data. Conservative estimates give |Vcb|=(42.4 +/- 1.2{exp} +/- 2.3{thy})x10^{-3} and |Vub|=(3.90 +/- 0.16{exp} +/- 0.53{thy})x10^{-3}. Using these values along with data on Bd, Bs mixing and CP violation in the K_{Long} system, the allowed region of the CKM parameters rho and eta is derived. Tests of factorization in two-body hadronic B decays to one heavy and one light meson are shown and compared with modern theories which are also used to see if there is new physics in two-body B decays to light mesons. The two new narrow D_{sJ} states, discovered by BaBar and CLEO, respectively, are interpreted in light of the observation of these states in B decays by Belle.Comment: Plenary talk at International Europhysics Conference on High Energy Physics EPS (July 17th-23rd 2003) in Aachen, Germany, 16 pages, 37 figures. Fixed Table 5 caption on Oct. 18 and errors on Nov. 5, 200

Radiation hardness qualification of PbWO_4 scintillation crystals for the CMS Electromagnetic Calorimeter

Ensuring the radiation hardness of PbWO_4 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