CP Violation: Recent Results from BABAR

We review recent time-dependent measurements in the B meson sector based on data collected between 1999 and 2002 by the BABAR detector, which correspond to approximately 88 million BB pairs.Comment: 8 pages - talk given on behalf of the BABAR Collaboration at the 38th Rencontres De Moriond On Electroweak Interactions And Unified Theories, 15-22 Mar 2003, Les Arcs, Franc

CP violation in the B meson system: recent experimental results

Recent experimental results on CP violation in the study of B meson decays are reviewed. The emphasis is put on the recent measurements of the CP parameter sin2beta by the BABAR and BELLE experiments at asymmetric B factories, which establish for the first time CP violation in the B meson system

CP Asymmetries of B→ϕKB \to \phi K and B→η(′)KB \to \eta^{(\prime)} K Decays Using a Global Fit in QCD Factorization

We analyze the CP asymmetries of $B\to \phi K$ and $B\to \eta^{(\prime)} K$ modes in the QCD improved factorization framework. For our calculation we use the phenomenological parameters predetermined from the global fit for the available $B\to PP$ and $VP$ modes (without the quark-level subprocess $b\to s\bar s s$). We show that the large negative $\sin (2\phi_1)_{\phi K_s}$ and the large branching ratio for $B^{\pm}\to \eta' K^{\pm}$ can be simultaneously explained in the context of supersymmetry (SUSY). The R-parity conserving SUGRA models are used and their parameter space is constrained with the observed dark matter relic density along with other experimental constraints. The R-parity violating SUSY models are also used to show that they can provide solutions. We calculate the CP asymmetries for different $B^{\pm (0)} \to \phi K^{\pm (0)}$ and $B^{\pm (0)} \to \eta^{(')} K^{\pm (0)}$ modes and show that the SUSY model predictions are consistent with the available experimental data.Comment: 13 pages, No figure; Some references adde

Flavor and CP violating Z exchange and the rate asymmetry in B --> phi K_S

Recent measurements of time dependent CP asymmetry in B --> phi K_S, if confirmed, would indicate a new source of CP violation. We examine flavor violating tree-level Z currents in models with extra down-type quark singlets that arise naturally in string compactified gauge groups like E_6. We evaluate the new operators at the scale mu = m_b in NLO, and using QCD improved factorization to describe B --> phi K_S, find the allowed range of parameters for rho and psi, the magnitude and phase of the flavor violating parameter U_{bs}. This allowed range does satisfy the constraint from flavor changing process b --> s l+ l- . However, further improvement in measurement of these rates could severely constrain the model.Comment: 15 pages, Latex, 2 postscript figures. Sections 2 and 3 are reordered. More references are added. Version to be published in PL

Gauge Theories and the Standard Model

This chapter, Chaps. 3 and 4 present a self-contained introduction to the Standard Model of fundamental interactions, which describes in the unified framework of gauge quantum field theories all of the fundamental forces of nature but gravity: the strong, weak, and electromagnetic interactions. This set of chapters thus provides both an introduction to the Standard Model, and to quantum field theory at an intermediate level. The union of the three chapters can be taken as a masters\u2019 level course reference, and it requires as a prerequisite an elementary knowledge of quantum field theory, at the level of many introductory textbooks, such as Vol. 1 of Aitchison-Hey, or, at a somewhat more advanced level, Maggiore. The treatment is subdivided into three parts, each corresponding to an individual chapter, with more advanced field theory topics introduced along the way as needed. Specifically, this chapter presents the general structure of the Standard Model, its field content, and symmetry structure. This involves an introduction to non-abelian gauge theories both at the classical and quantum level. Also, it involves a discussion of spontaneous symmetry breaking and the Higgs mechanism, that play a crucial role in the architecture of the Standard Model, and their interplay with the quantization of gauge theories. Chapter 3 then presents the electroweak sector of the Standard Model. This requires introducing the concepts of CP violation and mixing, and of radiative corrections. Finally, Chap. 4 presents the strong sector of the theory, which requires a more detailed treatment of renormalization and the renormalization group

Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up

Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated

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

Measurement of D-s(+) and D-s(*+) production in B meson decays and from continuum e(+)e(-) annihilation at √s=10.6 GeV

This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APSNew measurements of Ds+ and Ds*+ meson production rates from B decays and from qq̅ continuum events near the Υ(4S) resonance are presented. Using 20.8 fb-1 of data on the Υ(4S) resonance and 2.6 fb-1 off-resonance, we find the inclusive branching fractions B(B⃗Ds+X)=(10.93±0.19±0.58±2.73)% and B(B⃗Ds*+X)=(7.9±0.8±0.7±2.0)%, where the first error is statistical, the second is systematic, and the third is due to the Ds+→φπ+ branching fraction uncertainty. The production cross sections σ(e+e-→Ds+X)×B(Ds+→φπ+)=7.55±0.20±0.34pb and σ(e+e-→Ds*±X)×B(Ds+→φπ+)=5.8±0.7±0.5pb are measured at center-of-mass energies about 40 MeV below the Υ(4S) mass. The branching fractions ΣB(B⃗Ds(*)+D(*))=(5.07±0.14±0.30±1.27)% and ΣB(B⃗Ds*+D(*))=(4.1±0.2±0.4±1.0)% are determined from the Ds(*)+ momentum spectra. The mass difference m(Ds+)-m(D+)=98.4±0.1±0.3MeV/c2 is also measured.This work was supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the Swiss NSF, A. P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation

A search for the decay modes B+/- to h+/- tau l

We present a search for the lepton flavor violating decay modes B+/- to h+/- tau l (h= K,pi; l= e,mu) using the BaBar data sample, which corresponds to 472 million BBbar pairs. The search uses events where one B meson is fully reconstructed in one of several hadronic final states. Using the momenta of the reconstructed B, h, and l candidates, we are able to fully determine the tau four-momentum. The resulting tau candidate mass is our main discriminant against combinatorial background. We see no evidence for B+/- to h+/- tau l decays and set a 90% confidence level upper limit on each branching fraction at the level of a few times 10^-5.Comment: 15 pages, 7 figures, submitted to Phys. Rev.