I present a measurement of the CP violating asymmetry in D0 → π+π- decays using approximately 215,000 decays reconstructed in about 5.94 fb-1 of CDF data. We use the strong D*+ → D0 π+ decay ("D* tag") to identify the flavor of the charmed meson at production time and exploit CP-conserving strong c c-bar pair-production in p p-bar collisions. Higher statistic samples of Cabibbo-favored D0 →K- π+ decays with and without D*tag are used to highly suppress systematic uncertainties due to detector effects. The result, at the per mil level, is the world's most precise measurement to date.
SlidesRadiative Phi decays to scalars a_0, f_0, sigma and to pseudoscalars η and η' have been studied by the KLOE experiment at the DAFNE Phi factory. The decays of scalars to pi pi and eta pi have been analyzed according different theoretical models to infer information on their internal structure (q-qbar or four-quark states, or KK molecules). Precise measurements of the radiative Phi decays to eta and eta' allow to estimate the η/η' mixing angle. The impact of these measurements on the issue of the gluonium fraction inside the etaprime is discussed..
SlidesResults on two-particle angular correlations for charged particles emitted in proton-proton collisions at center of mass energies of 0.9, 2.36 and 7 TeV over a broad range of pseudorapidity (η) and azimuthal angle (φ) are presented using data collected with the CMS detector at the LHC. Short-range correlations in Δη, which are studied in minimum bias events, are characterized using a simple independent cluster parameterization in order to quantify their strength (cluster size) and their extent in η (cluster decay width). Long-range azimuthal correlations are studied more differentially as a function of charged particle multiplicity and particle transverse momentum using a 980 nb-1 data set at 7 TeV. In high multiplicity events, a pronounced structure emerges in the two-dimensional correlation function for particles in intermediate pT’s of 1-3 GeV/c, 2.0< |Δη|<4.8 and Δφ≈0. This is the first observation of such a ridge-like feature in two-particle correlation functions in pp or p-pbar collisions
The B0s mixing phase βs is a key probe of physics beyond the standard model (SM). The first Tevatron measurements hinted at a ~2σ departure from the SM expectations. We present a new analysis using B0s → J/ψ φ decays reconstructed in 5.2 fb-1 of data collected by CDF detector, where tightened bounds on the mixing phase are obtained along with an improved measurement of the decay-width difference ΔΓs and of B0s.
SlidesThe HARP-CDP group analyzed hadroproduction data recorded by the HARP detector at the CERN-PS. Objects of study are (i) double-differential inclusive cross-sections of proton and pion production on nuclei ranging from beryllium to lead that permit, inter alia, interesting comparisons between nuclei with different atomic number; and (ii) comparisons of the data with predictions of the FLUKA and the Geant4 programs. A further focus of interest is pion production by a 1.5 GeV/c proton beam, with a view to cross-checking the calculation of the electron-antineutrino background in the LSND experiment. Until now, a 3.8 sigma excess of electron-antineutrinos, claimed by LSND and known as "LSND anomaly", has been interpreted as evidence of muon-antineutrino to electron-antineutrino oscillations which in turn has led to the suggestion of "sterile" neutrinos. We report on an independent calculation of LSND's electron-antineutrino background, using HARP-CDP data, and taking into account pion production by neutrons which had been ignored in LSND's calculations. LSND's claim of a 3.8 sigma excess cannot be upheld.
SlidesAt the Paul Scherrer Institute, Switzerland, we have recently measured the 2S − 2P transition frequency (Lamb shift) in muonic hydrogen (μp) with 20 ppm precision by means of laser spectroscopy. From this measurement we have determined the rms charge radius of the proton. The new proton radius value rp = 084184(67)fm is 10 times more precise than previously obtained. However, it disagrees by 5 standard deviations from the current CODATA value and 3 standard deviations from e-p scattering results. The origin of this discrepancy is not yet known. It may come from theory of the muonic hydrogen energy levels (used to deduce the new value), or from problems in hydrogen spectroscopy experiments or hydrogen energy level theory (both used to deduce the CODATA value), or from new physics. Experimental setup, measurements and results will be presented. Additionally the key issues regarding the observed discrepancy will be discussed. The discrepancy simply raises new questions in the muonic sector, in bound-state QED and around the proton, holding the potential for new insights.
SlidesThe MiniBooNE neutrino oscillation search experiment at Fermilab has recently completed the analysis of anti-neutrino data it has collected in Fermilab's booster neutrino beam. With 5.66x10**20 protons on target in anti-neutrino mode the experiment is now becoming sensitive the the excess numubar-nuebar signal observed by LSND. This presentation will discuss the MiniBooNE data, its interpretation, and its implications to the neutrino community.
Slideshe GammeV laser experiments will be described which have already produced results for a search for low mass axion-like scalar and pseudoscalar particles. A modification of the design of the apparatus has allowed for a search for a chameleon particle - a possible particle candidate for dark energy. New results from GammeV-CHASE, a new dedicated CHameleon Afterglow Search Experiment, will be presented. Future work at Fermilab in this area includes R&D towards a much more sensitive axion-like particle search as well as a new initiative to test for the holographic nature of space time.
SlidesA precise understanding of jets at the D0 Experiment in RunII of the Tevatron has allowed for a plethora of measurements that tests perturbative QCD in several different ways. I will review recent cross section measurements of jets and vector boson + jets final states. These processes make up the overwhelming backgrounds to many New Physics searches. They are therefore critical backgrounds to measure precisely in order to make discoveries at the Tevatron or LHC.
SlidesWe measure the charge asymmetry A of like-sign dimuon events in 6.1 fb-1 of pp collisions recorded with the D0 detector at a center-of-mass energy √s = 1.96 TeV at the Fermilab Tevatron collider. From A, we extract the like-sign dimuon charge asymmetry in semileptonic b-hadron decays: Absl = -0.00957 ± 0.00251 (stat) ± 0.00146 (syst). This result differs by 3.2 standard deviations from the standard model prediction Absl(SM) = (-2.3+0.5 -0.6) x 10-4 and provides first evidence of anomalous CP-violation in the mixing of neutral B mesons.
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